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14 pages, 5168 KiB  
Article
Key Genes FECH and ALAS2 under Acute High-Altitude Exposure: A Gene Expression and Network Analysis Based on Expression Profile Data
by Yifan Zhao, Lingling Zhu, Dawei Shi, Jiayue Gao and Ming Fan
Genes 2024, 15(8), 1075; https://doi.org/10.3390/genes15081075 - 14 Aug 2024
Abstract
High-altitude acclimatization refers to the physiological adjustments and adaptation processes by which the human body gradually adapts to the hypoxic conditions of high altitudes after entering such environments. This study analyzed three mRNA expression profile datasets from the GEO database, focusing on 93 [...] Read more.
High-altitude acclimatization refers to the physiological adjustments and adaptation processes by which the human body gradually adapts to the hypoxic conditions of high altitudes after entering such environments. This study analyzed three mRNA expression profile datasets from the GEO database, focusing on 93 healthy residents from low altitudes (≤1400 m). Peripheral blood samples were collected for analysis on the third day after these individuals rapidly ascended to higher altitudes (3000–5300 m). The analysis identified significant differential expression in 382 genes, with 361 genes upregulated and 21 downregulated. Further, gene ontology (GO) annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that the top-ranked enriched pathways are upregulated, involving blood gas transport, erythrocyte development and differentiation, and heme biosynthetic process. Network analysis highlighted ten key genes, namely, SLC4A1, FECH, EPB42, SNCA, GATA1, KLF1, GYPB, ALAS2, DMTN, and GYPA. Analysis revealed that two of these key genes, FECH and ALAS2, play a critical role in the heme biosynthetic process, which is pivotal in the development and maturation of red blood cells. These findings provide new insights into the key gene mechanisms of high-altitude acclimatization and identify potential biomarkers and targets for personalized acclimatization strategies. Full article
(This article belongs to the Collection Feature Papers in Bioinformatics)
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Figure 1

Figure 1
<p>Summary of the overall workflow and related results of the gene expression analysis. This figure illustrates a comprehensive workflow starting with data selection from the GEO database, followed by visualization of DEGs. It progresses to functional enrichment analyses using GO and KEGG, identifying critical pathways like carbon dioxide transport and the heme biosynthetic process. Subsequent network analysis identifies three highly interconnected sub-networks and ten key genes, with their expression levels depicted in box plots. The Venn diagram highlights the overlap between the top 20 upregulated genes and the hub genes. Additionally, the expression of two pivotal genes, <span class="html-italic">FECH</span> and <span class="html-italic">ALAS2</span>, was validated using the GSE103927 dataset, showing significant upregulation and underscoring their roles in high-altitude acclimatization. *** denotes very significant (<span class="html-italic">p</span> &lt; 0.001), ** denotes significant (<span class="html-italic">p</span> &lt; 0.01), and * denotes moderately significant (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Differentially expressed genes in high-altitude conditions. Each point represents a gene, with the <span class="html-italic">x</span>-axis showing the log<sub>2</sub> fold change (log<sub>2</sub>(FC)) to indicate the magnitude of gene expression changes and the <span class="html-italic">y</span>-axis showing the negative log<sub>10</sub> transformation of the adjusted <span class="html-italic">p</span>-value (−log<sub>10</sub>(p.adj)), emphasizing the statistical significance of these changes. (<b>A</b>). Significant upregulation and downregulation thresholds are set at |log<sub>2</sub>(FC)| ≥ 1 and p.adj &lt; 0.05. A heatmap illustrates the patterns of gene expression across different samples, with the color scale representing the intensity of gene expression (<b>B</b>).</p>
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<p>Functional enrichment results of the gene expression data. The GO enrichment results for significant gene expression data under high-altitude conditions are divided into three main categories as follows: BP, CC, and MF. Each bar graph represents the enrichment level of a specific GO term, with the length of the bar indicating the fold enrichment, which represents the enrichment ratio compared to the expected random value. The depth of the color represents the logarithmic value of the <span class="html-italic">p</span>-value (<b>A</b>). The KEGG analysis results for significantly differentially expressed genes, displaying the fold enrichment of various KEGG pathways and their corresponding statistical significance (<span class="html-italic">p</span>-value), with the size of the dots representing the number of genes enriched in each pathway (<b>B</b>).</p>
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<p>Top 20 significantly upregulated and downregulated genes. <a href="#genes-15-01075-f004" class="html-fig">Figure 4</a> shows the top 20 significantly upregulated and downregulated genes, respectively. The top 20 genes with the smallest <span class="html-italic">p</span>-values were selected to represent their significance in upregulation and downregulation, which are sorted by log<sub>2</sub> (FC) values.</p>
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<p>Analysis of protein interaction networks and key molecular expressions. This network diagram is based on the GO and KEGG pathway analysis results under high-altitude conditions. The network analysis results for significant genes display the interaction patterns among significant genes within the cell. The nodes in the diagram represent individual genes, and the connections among nodes represent protein interactions identified through scientific literature and bioinformatics predictions (<b>A</b>). Highly interconnected sub-networks identified within the network. Each sub-network’s score indicates the connectivity density and the strength of interactions among the nodes in the network (<b>B</b>–<b>D</b>). The expression levels of key genes under different conditions (HA and SL) with asterisks indicating statistical significance as follows: *** denotes very significant (<span class="html-italic">p</span> &lt; 0.001), ** denotes significant (<span class="html-italic">p</span> &lt; 0.01), and * denotes moderately significant (<span class="html-italic">p</span> &lt; 0.05) (<b>E</b>). Venn diagram illustrating the common genes between key genes and the top 20 DEGs (<b>F</b>).</p>
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<p>Boxplots of <span class="html-italic">FECH</span> and <span class="html-italic">ALAS2</span> gene expression levels in plains and at high altitudes. Boxplot showing the expression level of the <span class="html-italic">FECH</span> gene in plains (SL) and high-altitude (HA) environments. The expression levels are generally higher in the HA group, indicated by a single asterisk (*), representing a <span class="html-italic">p</span>-value &lt; 0.05 (<b>A</b>). Boxplot displaying the expression level of the <span class="html-italic">ALAS2</span> gene in the same environments. There is a significant increase in expression levels in the HA group, as indicated by the asterisks (***), representing a <span class="html-italic">p</span>-value &lt; 0.001 (<b>B</b>).</p>
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14 pages, 2161 KiB  
Article
Brain Region-Specific Expression Levels of Synuclein Genes in an Acid Sphingomyelinase Knockout Mouse Model: Correlation with Depression-/Anxiety-Like Behavior and Locomotor Activity in the Absence of Genotypic Variation
by Razvan-Marius Brazdis, Iulia Zoicas, Johannes Kornhuber and Christiane Mühle
Int. J. Mol. Sci. 2024, 25(16), 8685; https://doi.org/10.3390/ijms25168685 - 9 Aug 2024
Viewed by 276
Abstract
Accumulating evidence suggests an involvement of sphingolipids, vital components of cell membranes and regulators of cellular processes, in the pathophysiology of both Parkinson’s disease and major depressive disorder, indicating a potential common pathway in these neuropsychiatric conditions. Based on this interaction of sphingolipids [...] Read more.
Accumulating evidence suggests an involvement of sphingolipids, vital components of cell membranes and regulators of cellular processes, in the pathophysiology of both Parkinson’s disease and major depressive disorder, indicating a potential common pathway in these neuropsychiatric conditions. Based on this interaction of sphingolipids and synuclein proteins, we explored the gene expression patterns of α-, β-, and γ-synuclein in a knockout mouse model deficient for acid sphingomyelinase (ASM), an enzyme catalyzing the hydrolysis of sphingomyelin to ceramide, and studied associations with behavioral parameters. Normalized Snca, Sncb, and Sncg gene expression was determined by quantitative PCR in twelve brain regions of sex-mixed homozygous (ASM−/−, n = 7) and heterozygous (ASM+/−, n = 7) ASM-deficient mice, along with wild-type controls (ASM+/+, n = 5). The expression of all three synuclein genes was brain region-specific but independent of ASM genotype, with β-synuclein showing overall higher levels and the least variation. Moreover, we discovered correlations of gene expression levels between brain regions and depression- and anxiety-like behavior and locomotor activity, such as a positive association between Snca mRNA levels and locomotion. Our results suggest that the analysis of synuclein genes could be valuable in identifying biomarkers and comprehending the common pathological mechanisms underlying various neuropsychiatric disorders. Full article
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Graphical abstract

Graphical abstract
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<p>Brain-specific variation of α, β-, and γ-synuclein gene expression in twelve regions with uniformity across the three acid sphingomyelinase (ASM) genotypes. (<b>a</b>) <span class="html-italic">Snca</span>, (<b>b</b>) <span class="html-italic">Sncb</span>, and (<b>c</b>) <span class="html-italic">Sncg</span> were expressed differently in twelve brain regions: frontal cortex (FC), dorsal striatum (DS), lateral septum (LS), ventral striatum (VS), amygdala (AM), dorsal hippocampus (DH), thalamus (TH), hypothalamus (HY), ventral hippocampus (VH), dorsal mesencephalon (DM), ventral mesencephalon (VM), and cerebellum (CE). No statistically significant differences were observed between homozygous ASM-deficient (ASM−/−, <span class="html-italic">n</span> = 7), heterozygous ASM-deficient (ASM+/−, <span class="html-italic">n</span> = 7), and wild-type (ASM+/+, <span class="html-italic">n</span> = 5) mice. Data represent individual data points with means as bars.</p>
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<p>Heat maps of Spearman correlation coefficient (ρ) between (<b>a</b>) <span class="html-italic">Snca</span>, (<b>b</b>) <span class="html-italic">Sncb</span>, and (<b>c</b>) <span class="html-italic">Sncg</span> expression in twelve brain regions, frontal cortex (FC), dorsal striatum (DS), lateral septum (LS), ventral striatum (VS), amygdala (AM), dorsal hippocampus (DH), thalamus (TH), hypothalamus (HY), ventral hippocampus (VH), dorsal mesencephalon (DM), ventral mesencephalon (VM), and cerebellum (CE), for the entire group of mice (total, <span class="html-italic">n</span> = 19). ρ index ranges from −1 to +1; blue indicates a positive correlation, and red a negative correlation (darker color indicates a stronger correlation); white (ρ = 0) represents no correlation. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01 for the significance level of the correlation.</p>
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<p>The behavioral phenotype of homozygous ASM knockout (ASM−/−, <span class="html-italic">n</span> = 7), heterozygous ASM-deficient (ASM+/−, <span class="html-italic">n</span> = 7), and wild-type (ASM+/+, <span class="html-italic">n</span> = 5) mice. (<b>a</b>) Percentage of immobility time, as an indicator of depression-like behavior, was assessed in the forced swim test; (<b>b</b>) Percentage of time spent in the open arms of the elevated plus-maze is an indicator of anxiety-like behavior; (<b>c</b>) The number of entries into the closed arm of the elevated plus-maze is an indicator of locomotor activity; (<b>a</b>,<b>b</b>) ASM−/− mice showed a reduced depression-like phenotype, but increased anxiety-like behavior compared with ASM+/+ mice. Locomotor activity was reduced in ASM−/− mice compared with ASM+/− mice. Data represent the means + SEM. * <span class="html-italic">p</span> &lt; 0.05.</p>
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<p>Heat maps of Spearman correlation coefficient (ρ) between (<b>a</b>) <span class="html-italic">Snca</span>, (<b>b</b>) <span class="html-italic">Sncb</span>, and (<b>c</b>) <span class="html-italic">Sncg</span> expression and depression-like behavior (D) expressed as percentage immobility in the forced swim test, anxiety-like behavior (A) indicated by the percentage of time spent in the open arms of the elevated plus-maze, and locomotor activity (L) assessed by the number of closed arm entries in the elevated plus-maze in twelve brain regions: frontal cortex (FC), dorsal striatum (DS), lateral septum (LS), ventral striatum (VS), amygdala (AM), dorsal hippocampus (DH), thalamus (TH), hypothalamus (HY), ventral hippocampus (VH), dorsal mesencephalon (DM), ventral mesencephalon (VM), and cerebellum (CE), for the entire group of mice [<span class="html-italic">n</span> = 19, male <span class="html-italic">n</span> = 8, female <span class="html-italic">n</span> = 11; wild-type (ASM+/+) <span class="html-italic">n</span> = 5, homozygous ASM-deficient (ASM−/−) <span class="html-italic">n</span> = 7 and heterozygous ASM-deficient (ASM+/−) <span class="html-italic">n</span> = 7]. ρ index ranges from −1 to +1; blue indicates a positive correlation, and red a negative correlation (darker color indicates a stronger correlation); white (ρ = 0) represents no correlation. * <span class="html-italic">p</span> &lt; 0.05 for the significance level of the correlation.</p>
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<p>Associations of synuclein expression data with behavioral measures: (<b>a</b>) Negative correlation of <span class="html-italic">Sncb</span> expression with depression-like behavior, expressed as percentage immobility in the forced swim test, in the ventral striatum (VS) of female (red, <span class="html-italic">n</span> = 8) and male (blue, <span class="html-italic">n</span> = 11) mice; (<b>b</b>) Positive correlation of <span class="html-italic">Snca</span> expression with percentage of time spent in the open arms of the elevated plus-maze, as an inverse indicator of anxiety-like behavior, in the amygdala (AM) of female (red) and male (blue) heterozygous ASM-deficient (ASM+/−, <span class="html-italic">n</span> = 7) mice; (<b>c</b>) Positive correlation of <span class="html-italic">Snca</span> expression with number of closed arm entries in the elevated plus-maze, as an indicator of locomotor activity, in the cerebellum (CE) of combined female homozygous ASM-deficient (ASM−/−, <span class="html-italic">n</span> = 1), heterozygous ASM-deficient (ASM+/−, <span class="html-italic">n</span> = 4), and wild-type (ASM+/+, <span class="html-italic">n</span> = 3) mice, (<b>d</b>) as well as in female ASM+/+ (<span class="html-italic">n</span> = 3) and male ASM+/+ (<span class="html-italic">n</span> = 2) mice. Linear regression line for the combined group with 95% confidence interval and statistics (Spearman correlation, <span class="html-italic">p</span> &lt; 0.05).</p>
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19 pages, 1921 KiB  
Review
Novel Therapeutic Horizons: SNCA Targeting in Parkinson’s Disease
by Alessio Maria Caramiello and Valentina Pirota
Biomolecules 2024, 14(8), 949; https://doi.org/10.3390/biom14080949 - 6 Aug 2024
Viewed by 466
Abstract
Alpha-synuclein (αSyn) aggregates are the primary component of Lewy bodies, which are pathological hallmarks of Parkinson’s disease (PD). The toxicity of αSyn seems to increase with its elevated expression during injury, suggesting that therapeutic approaches focused on reducing αSyn burden in neurons could [...] Read more.
Alpha-synuclein (αSyn) aggregates are the primary component of Lewy bodies, which are pathological hallmarks of Parkinson’s disease (PD). The toxicity of αSyn seems to increase with its elevated expression during injury, suggesting that therapeutic approaches focused on reducing αSyn burden in neurons could be beneficial. Additionally, studies have shown higher levels of SNCA mRNA in the midbrain tissues and substantia nigra dopaminergic neurons of sporadic PD post-mortem brains compared to controls. Therefore, the regulation of SNCA expression and inhibition of αSyn synthesis could play an important role in the pathogenesis of injury, resulting in an effective treatment approach for PD. In this context, we summarized the most recent and innovative strategies proposed that exploit the targeting of SNCA to regulate translation and efficiently knock down cytoplasmatic levels of αSyn. Significant progress has been made in developing antisense technologies for treating PD in recent years, with a focus on antisense oligonucleotides and short-interfering RNAs, which achieve high specificity towards the desired target. To provide a more exhaustive picture of this research field, we also reported less common but highly innovative strategies, including small molecules, designed to specifically bind 5′-untranslated regions and, targeting secondary nucleic acid structures present in the SNCA gene, whose formation can be modulated, acting as a transcription and translation control. To fully describe the efficiency of the reported strategies, the effect of αSyn reduction on cellular viability and dopamine homeostasis was also considered. Full article
(This article belongs to the Section Biomacromolecules: Nucleic Acids)
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Figure 1
<p>Common chemical modifications to improve classical ASO features.</p>
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<p>Chemical structure of AmNA and LNA phosphorothioate moieties.</p>
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<p>siRNA pathway: ribonuclease protein Dicer recognizes and cleaves DNA double-strand into small fragments (21–23 bp), known as siRNAs, which form the protein RISC complex. Then, siRNA binds the target sequence on mRNA, inducing its cleavage into small fragments (10–11 bp). This results in the suppression of mRNA translation.</p>
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<p>Chemical structures of ligands targeting 5′-UTR of <span class="html-italic">SNCA</span> mRNA.</p>
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<p>Schematic representation of (<b>A</b>) square-planar G-tetrad; (<b>B</b>) backbone of the intramolecular G-quadruplex structure; (<b>C</b>) G4 topologies: parallel-, antiparallel-, and hybrid-type G4 structures.</p>
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<p>Cartoon representing the three G4 motifs identified in the 5′-UTR mRNA region of the <span class="html-italic">SNCA</span> gene by Koukouraki et al. [<a href="#B78-biomolecules-14-00949" class="html-bibr">78</a>], together with all the G to A mutations tested (highlighted in yellow).</p>
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18 pages, 10701 KiB  
Article
The Aggregation of α-Synuclein in the Dorsomedial Striatum Significantly Impairs Cognitive Flexibility in Parkinson’s Disease Mice
by Jing Chen, Yifang Liu, Mingyu Su, Yaoyu Sun, Chenkai Liu, Sihan Sun, Ting Wang and Chuanxi Tang
Biomedicines 2024, 12(8), 1634; https://doi.org/10.3390/biomedicines12081634 - 23 Jul 2024
Viewed by 461
Abstract
This study focused on α-synuclein (α-syn) aggregation in the dorsomedial striatum (DMS) so as to investigate its role in the cognitive flexibility of Parkinson’s disease (PD). Here, we investigated the cognitive flexibility by assessing reversal learning abilities in MPTP-induced subacute [...] Read more.
This study focused on α-synuclein (α-syn) aggregation in the dorsomedial striatum (DMS) so as to investigate its role in the cognitive flexibility of Parkinson’s disease (PD). Here, we investigated the cognitive flexibility by assessing reversal learning abilities in MPTP-induced subacute PD model mice and in C57BL/6J mice with α-syn aggregation in the DMS induced by adenovirus (AAV-SNCA) injection, followed by an analysis of the target protein’s expression and distribution. PD mice exhibited impairments in reversal learning, positively correlated with the expression of phosphorylated α-syn in the DMS. Furthermore, the mice in the AAV-SNCA group exhibited reversal learning deficits and a reduction in acetylcholine levels, accompanied by protein alterations within the DMS. Notably, the administration of a muscarinic receptor 1 (M1R) agonist was able to alleviate the aforementioned phenomenon. These findings suggest that the impaired cognitive flexibility in PD may be attributed to the diminished activation of acetylcholine to M1R caused by α-syn aggregation. Full article
(This article belongs to the Section Neurobiology and Clinical Neuroscience)
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<p>Mode diagram of small animal touch screen system.</p>
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<p>MPTP subacute Parkinson’s disease (PD) model was established. (<b>A</b>) The timeline for experimental arrangement. (<b>B1</b>,<b>B2</b>) Rotarod test and (<b>C1</b>,<b>C2</b>) Open-field test results suggested that the mice of MPTP group exhibited motor disability (<span class="html-italic">n</span> = 15–16 mice, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. control group). (<b>D1</b>,<b>D2</b>) Western Blotting (WB) results for TH in substantia nigra, showed decreased expression in MPTP group (<span class="html-italic">n</span> = 3, *** <span class="html-italic">p</span> &lt; 0.001 vs. control group). (<b>E1</b>,<b>E2</b>) Immunofluorescence (IF) results showed that the distribution of TH+ positive neurons decreased in MPTP group (<span class="html-italic">n</span> = 5, *** <span class="html-italic">p</span> &lt; 0.001 vs. control group). Scale bar: 200 µm.</p>
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<p>The PD mice demonstrate impaired reversal learning abilities associated with the accumulation of alpha-synuclein (<math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn). (<b>A</b>) Behavioral paradigm diagram of the modified Morris water maze (MWM). (<b>B</b>) The latency target index (referring to the time taken by the mice to reach the plateau quadrant for the first time during testing) serves as an indicator of reversal learning performance; low index indicates poor reversal learning in the MPTP group ((training test − reversal test)/(training test + reversal test); <span class="html-italic">n</span> = 15–16 mice, ** <span class="html-italic">p</span> &lt; 0.01 vs. control group). The lower the index, the worse the ability in reversal learning. (<b>C</b>) Time spent in each quadrant by mice in the reversal learning phase showed that the MPTP group spent relatively more time in the original quadrant compared to the control group (<span class="html-italic">n</span> = 15–16 mice). (<b>D</b>,<b>E</b>) WB results for <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn and p-<math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn in the dorsomedial striatum, showed increased expression in the low-index (index ≤ 0.85) group (<span class="html-italic">n</span> = 3; * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01 vs. control group; # <span class="html-italic">p</span> &lt; 0.05 vs. high group (index &gt; 0.85)); while, the statistical difference in the levels of <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn between the Index high and Index low groups was not significant. (<b>F</b>) Pearson correlation analysis of p-<math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn expression and reverse learning index (<span class="html-italic">n</span> = 17 mice, r = −0.932, <span class="html-italic">p</span> &lt; 0.01).</p>
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<p>Reversal learning deficits were observed upon accumulation of <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn in the dorsomedial striatum. (<b>A</b>) Schematic diagram of cerebral stereotactic drug delivery, and AAV-SNCA spread region in the striatum visualized in green. (<b>B</b>,<b>C</b>) WB results for <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn and p-<math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn in the striatum showing increased expression in the AAV-SNCA group (<span class="html-italic">n</span> = 3, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-NC group). (<b>D</b>) IF results for striatal p-<math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn (scale bar: 200 μm). (<b>E1</b>,<b>E2</b>) Behavioral paradigm diagram of pairwise discrimination acquisition phases and reversal learning phases in the small animal touchscreen systems. (<b>F1</b>) Correctness per day for each group in the pairwise discrimination learning phase when 50% of the mice reach the criterion (&gt;80% correct on two consecutive days). (<b>F2</b>–<b>F4</b>) The number of errors corrected, learning sessions and time required to achieve the criterion in the pairwise discrimination learning phase. (<b>G1</b>) Correctness per day for each group in the reversal phase when 50% of the mice reach the criterion. (<b>G2</b>–<b>G4</b>) The number of errors corrected, learning sessions and time required to achieve the criterion in the reversal phase. (<span class="html-italic">n</span> = 6–7 mice, * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001 vs. AAV-NC group.</p>
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<p>The aggregation of <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn in the dorsomedial striatum inhibited acetylcholine (Ach) release from cholinergic interneurons (ChI). (<b>A</b>–<b>C</b>) WB results and statistical analysis of NR2D and Choline acetyl transferase (ChAT) in the dorsomedial striatum (<span class="html-italic">n</span> = 3, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-NC group); however, there was no statistically significant difference observed in the levels of ChAT between the AAV-NC group and the AAV-SNCA group. (<b>D</b>) ELISA results showed a decrease in ACh content in the dorsomedial striatum of mice in the AAV-SNCA group (<span class="html-italic">n</span> = 8, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-NC group). (<b>E</b>–<b>G</b>) WB results and statistical analysis of Snap25 and Syntaxin in the dorsomedial striatum (<span class="html-italic">n</span> = 3, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-NC group).</p>
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<p>The aggregation of <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn led to diminished activation on indirect pathway spiny projection neurons (iSPNs). (<b>A</b>–<b>C</b>) WB results and statistical analysis of c-Fos and M1R in the dorsomedial striatum. (<b>D</b>,<b>E</b>) The WB results were obtained for phosphorylated Erk (p-Erk), total Erk, and the ratio of p-Erk to Erk expression. (<b>F</b>,<b>G</b>) The WB results were obtained for phosphorylated AKT (p-AKT), total AKT, and the ratio of p-AKT to AKT expression. (<b>H</b>–<b>J</b>) WB results and statistical analysis of PSD 95 and CaMKII in the dorsomedial striatum. (<span class="html-italic">n</span> = 3, * <span class="html-italic">p</span> &lt; 0.05 vs. AAV-NC group).</p>
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<p>M1R activation mitigates the reversal learning deficits induced by <math display="inline"><semantics> <mi>α</mi> </semantics></math>-syn aggregation in mice. (<b>A</b>) Experimental flow chart of drug administration and small animal touchscreen systems. (<b>B</b>,<b>C</b>) Statistical analysis of the time required and the number of errors corrected to achieve the criterion in the pairwise discrimination learning phase (<span class="html-italic">n</span> = 12 mice). (<b>D</b>,<b>E</b>) Statistical analysis of the time required and the number of errors corrected to achieve the criterion in the first reversal learning phase (<span class="html-italic">n</span> = 12 mice, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-NC group). (<b>F</b>,<b>G</b>) Statistical analysis of the time required and the number of errors corrected to achieve the criterion in the second reversal learning phase (<span class="html-italic">n</span> = 6 mice, * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01 vs. AAV-SNCA + DMSO group); however, there was no significant difference between AAV-NC + DMSO and AAV-NC + VU0357017 groups. (<b>H</b>,<b>I</b>) Before and after intraperitoneal injection of M1R activator, statistical analysis of the time required and the number of errors corrected to achieve the criterion in the second reversal learning phase. A significant reduction in both the time required to achieve the criterion and the number of error corrections in the mice of the AAV-SNCA group were observed after intraperitoneal injection of U0357017 (** <span class="html-italic">p</span> &lt; 0.01), whereas such effects were conspicuously absent in the AAV-NC group. Additionally, no significant differences were observed in these parameters in the two groups (AAV-NC and AAV-SNCA groups) before and after intraperitoneal injection of DMSO.</p>
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<p>Summary diagram.</p>
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22 pages, 30049 KiB  
Article
Alpha-Synuclein Gene Alterations Modulate Tyrosine Hydroxylase in Human iPSC-Derived Neurons in a Parkinson’s Disease Animal Model
by Luis Daniel Bernal-Conde, Verónica Peña-Martínez, C. Alejandra Morato-Torres, Rodrigo Ramos-Acevedo, Óscar Arias-Carrión, Francisco J. Padilla-Godínez, Alexa Delgado-González, Marcela Palomero-Rivero, Omar Collazo-Navarrete, Luis O. Soto-Rojas, Margarita Gómez-Chavarín, Birgitt Schüle and Magdalena Guerra-Crespo
Life 2024, 14(6), 728; https://doi.org/10.3390/life14060728 - 5 Jun 2024
Viewed by 1157
Abstract
Parkinson’s disease (PD) caused by SNCA gene triplication (3XSNCA) leads to early onset, rapid progression, and often dementia. Understanding the impact of 3XSNCA and its absence is crucial. This study investigates the differentiation of human induced pluripotent stem cell (hiPSC)-derived [...] Read more.
Parkinson’s disease (PD) caused by SNCA gene triplication (3XSNCA) leads to early onset, rapid progression, and often dementia. Understanding the impact of 3XSNCA and its absence is crucial. This study investigates the differentiation of human induced pluripotent stem cell (hiPSC)-derived floor-plate progenitors into dopaminergic neurons. Three different genotypes were evaluated in this study: patient-derived hiPSCs with 3XSNCA, a gene-edited isogenic line with a frame-shift mutation on all SNCA alleles (SNCA 4KO), and a normal wild-type control. Our aim was to assess how the substantia nigra pars compacta (SNpc) microenvironment, damaged by 6-hydroxydopamine (6-OHDA), influences tyrosine hydroxylase-positive (Th+) neuron differentiation in these genetic variations. This study confirms successful in vitro differentiation into neuronal lineage in all cell lines. However, the SNCA 4KO line showed unusual LIM homeobox transcription factor 1 alpha (Lmx1a) extranuclear distribution. Crucially, both 3XSNCA and SNCA 4KO lines had reduced Th+ neuron expression, despite initial successful neuronal differentiation after two months post-transplantation. This indicates that while the SNpc environment supports early neuronal survival, SNCA gene alterations—either amplification or knock-out—negatively impact Th+ dopaminergic neuron maturation. These findings highlight SNCA’s critical role in PD and underscore the value of hiPSC models in studying neurodegenerative diseases. Full article
(This article belongs to the Section Animal Science)
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<p>Overview of experimental methods. (<b>A</b>) In vitro dopaminergic differentiation protocol applied to wild-type, 3X<span class="html-italic">SNCA</span>, and SNCA 4KO hiPSC lines. (<b>B</b>) Stereotaxic 6-OHDA injection into left SNpc and transplantation of 125,000 hiPSCs at floor-plate stage (fifth expansion passage). (<b>C</b>) Representative coronal section images: (<b>I</b>) Striatal nucleus denervation in the left hemisphere (lesion site) shown by reduced tyrosine hydroxylase (Th, red signal) in the striatum (white triangles) contrasted with physiological Th expression in the contralateral striatum (white arrows) (right hemisphere). Scale: 1000 µm. (<b>II</b>) Similar denervation in the ipsilateral SNpc (white triangles) vs. (<b>III</b>) physiological Th expression in the uninjured contralateral SNpc (white arrows) (right side). Scale: 250 µm. Abbreviations: FP—floor-plate progenitor; T—transplant.</p>
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<p>Doublecortin and β-III Tubulin expression in hiPSC-derived floor-plate progenitors. Representative images from wild-type (<b>A</b>–<b>D</b>), 3X<span class="html-italic">SNCA</span> (<b>E</b>–<b>H</b>), and <span class="html-italic">SNCA</span> 4KO (<b>I</b>–<b>L</b>) hiPSC lines at floor-plate progenitor stage corresponding to day 25 of differentiation. All lines show similar morphology and consistent expression of doublecortin (Dcx) (<b>A</b>,<b>E</b>,<b>I</b>) and β-III Tubulin (<b>B</b>,<b>F</b>,<b>J</b>), with comparable signaling patterns. Includes DAPI for nuclear staining. Scale bar: 15 µm. (<b>M</b>) Quantitative analysis of neuroblast (Dcx) and neuronal (β-III Tubulin) markers reveals a significant reduction in Dcx expression in the 3X<span class="html-italic">SNCA</span> line and a significant increase in β-III Tubulin expression in the <span class="html-italic">SNCA</span> 4KO line. Error bars indicate standard deviation. Abbreviations: Dcx (doublecortin), NS (not significant). * <span class="html-italic">p</span> &lt; 0.01.</p>
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<p>Lmx1a expression in hiPSC-derived floor-plate progenitors. Representative images from wild-type (<b>A</b>–<b>D</b>), 3X<span class="html-italic">SNCA</span> (<b>E</b>–<b>H</b>), and <span class="html-italic">SNCA</span> 4KO (<b>I</b>–<b>L</b>) hiPSC lines at floor-plate progenitor stage corresponding to day 25 of differentiation. Notably, wild-type (<b>B</b>) and 3X<span class="html-italic">SNCA</span> (<b>F</b>) lines demonstrate distinct Lmx1a signal patterns compared to <span class="html-italic">SNCA</span> 4KO (<b>J</b>). White arrowheads (<b>D</b>,<b>H</b>,<b>L</b>) indicate Lmx1a signals primarily near the axon hillock, contrasting with the dispersed nucleoplasm signals (white arrows, <b>D</b>,<b>H</b>,<b>L</b>). DAPI was used for nuclear staining. Scale bar: 15 µm. (<b>M</b>) Analysis of Lmx1a-positive cells shows a significant reduction in nuclear and extranuclear expression in the <span class="html-italic">SNCA</span> 4KO line compared to wild-type and 3X<span class="html-italic">SNCA</span> lines. Error bars indicate standard deviation. Abbreviations: Lmx1a (LIM homeobox transcription factor 1 alpha). * <span class="html-italic">p</span> &lt; 0.01.</p>
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<p>Tyrosine hydroxylase expression in hiPSC-derived floor-plate progenitors. Representative images from wild-type (<b>A</b>–<b>D</b>), 3X<span class="html-italic">SNCA</span> (<b>E</b>–<b>H</b>), and <span class="html-italic">SNCA</span> 4KO (<b>I</b>–<b>L</b>) hiPSC lines at floor-plate progenitor stage corresponding to day 25 of differentiation. Across these lines, a similar proportion of cells exhibit expression of the dopaminergic neuron marker tyrosine hydroxylase (Th) (<b>B</b>,<b>F</b>,<b>J</b>). DAPI was used for nuclear staining. Scale bar: 15 µm. (<b>M</b>) Quantitative analysis of dopaminergic (Th) marker reveals no significant differences in Th expression. Error bars indicate standard deviation. Abbreviations: Th (tyrosine hydroxylase), NS (not significant).</p>
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<p>Tyrosine hydroxylase/alpha-synuclein expression in hiPSC-derived floor-plate progenitors. Representative images from wild-type (<b>A</b>–<b>D</b>) and 3X<span class="html-italic">SNCA</span> (<b>E</b>–<b>H</b>) hiPSC lines at floor-plate progenitor stage corresponding to day 25 of differentiation. A lower α-synuclein (α-syn) concentration is noted in the wild-type line (<b>A</b>–<b>D</b>) compared to the 3X<span class="html-italic">SNCA</span> line (<b>E</b>–<b>H</b>). The <span class="html-italic">SNCA</span> 4KO line (<b>I</b>–<b>L</b>), in contrast, shows no α-syn signal. DAPI was used for nuclear staining. Scale bar: 15 µm. (<b>M</b>) Quantification of α-syn and α-syn/Th co-expression highlights significant variations, especially in the 3X<span class="html-italic">SNCA</span> line. Error bars indicate standard deviation. Abbreviations: Th (tyrosine hydroxylase), α-syn (α-synuclein), NS (not significant). * <span class="html-italic">p</span> &lt; 0.01.</p>
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<p>Survival of transplanted hiPSC-derived floor-plate progenitors at two months post-transplantation. Representative photomicrographs of wild-type (<b>A</b>,<b>D</b>), 3X<span class="html-italic">SNCA</span> (<b>B</b>,<b>E</b>), and <span class="html-italic">SNCA</span> 4KO (<b>C</b>,<b>F</b>) hiPSC lines under sham (<b>A</b>–<b>C</b>) and 6-OHDA-lesioned conditions (<b>D</b>–<b>F</b>). The images illustrate the survival of these cell lines in both SNpc conditions, assessed using the human cell marker STEM121 (green). DAPI (blue) was used for nuclear staining. Scale bar: 250 µm. (<b>G</b>) Percentage of rats with floor-plate surviving transplants at two months post-transplantation (mpt) and the number of rats grafted. The data show the % of rats out of the total transplanted (<span class="html-italic">n</span> = 39), showing graft survival via a positive STEM121 signal both in sham and 6-OHDA-lesioned SNpc. Cell survival was evaluated in at least three brain slides for each rat. Survival % (percentage of rats with graft survival), <span class="html-italic">n</span> (total number of transplanted rats).</p>
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<p>Post-transplant doublecortin and β-III tubulin expression in hiPSC-derived floor-plate progenitors<b>.</b> Representative images from wild-type (<b>A</b>–<b>H</b>), 3X<span class="html-italic">SNCA</span> (<b>I</b>–<b>P</b>), and <span class="html-italic">SNCA</span> 4KO (<b>Q</b>–<b>X</b>) hiPSC lines two months post-transplantation. All three lines exhibit positive staining for doublecortin (Dcx) (<b>A</b>,<b>E</b>,<b>I</b>,<b>M</b>,<b>Q</b>,<b>U</b>) and β-III Tubulin (<b>B</b>,<b>F</b>,<b>J</b>,<b>N</b>,<b>R</b>,<b>V</b>) in both sham and 6-OHDA models, suggesting ongoing neuronal maturation. DAPI was used for nuclear staining. Scale bar: 15 µm.</p>
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<p>Tyrosine hydroxylase expression in transplanted hiPSC-derived floor-plate progenitors at two months post-transplantation. Representative images of wild-type (<b>A</b>–<b>H</b>), 3X<span class="html-italic">SNCA</span> (<b>I</b>–<b>P</b>), and <span class="html-italic">SNCA</span> 4KO (<b>Q</b>–<b>X</b>) hiPSC lines. These images show Th expression in cells transplanted at the floor-plate phase, assessed two months post-transplantation, in the small regions where the Th signal was observed. The human cell marker STEM121 was utilized to identify human transplanted cells. Notably, a reduction in Th+ signal was observed in both 3X<span class="html-italic">SNCA</span> (<b>J</b>,<b>N</b>) and <span class="html-italic">SNCA</span> 4KO (<b>R</b>,<b>V</b>) lines. In orthogonal views (<b>D</b>,<b>H</b>,<b>L</b>,<b>P</b>,<b>T</b>,<b>X</b>), cross-sections emphasize regions of intense factor colocalization. Scale bar: 30 µm. Abbreviations: Th (tyrosine hydroxylase).</p>
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<p>Alpha-synuclein expression in transplanted hiPSC-derived floor-plate progenitors at two months post-transplantation. Representative images from wild-type (<b>A</b>–<b>H</b>), 3X<span class="html-italic">SNCA</span> (<b>I</b>–<b>P</b>), and <span class="html-italic">SNCA</span> 4KO (<b>Q</b>–<b>X</b>) hiPSC lines. These images depict α-syn expression in cells transplanted at the floor-plate phase, assessed two months post-transplantation. Notably, an increase in α-syn is seen in the 3X<span class="html-italic">SNCA</span> line (<b>J</b>,<b>L</b>,<b>N</b>,<b>P</b>), compared to the wild-type (<b>B</b>,<b>D</b>,<b>F</b>,<b>H</b>), while no expression is observed in the <span class="html-italic">SNCA</span> 4KO line (<b>R</b>,<b>T</b>,<b>V</b>,<b>X</b>). Scale bar: 15 µm. Abbreviations: α-syn (alpha-synuclein).</p>
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23 pages, 3678 KiB  
Article
Enhanced Wind Field Spatial Downscaling Method Using UNET Architecture and Dual Cross-Attention Mechanism
by Jieli Liu, Chunxiang Shi, Lingling Ge, Ruian Tie, Xiaojian Chen, Tao Zhou, Xiang Gu and Zhanfei Shen
Remote Sens. 2024, 16(11), 1867; https://doi.org/10.3390/rs16111867 - 23 May 2024
Cited by 1 | Viewed by 516
Abstract
Before 2008, China lacked high-coverage regional surface observation data, making it difficult for the China Meteorological Administration Land Data Assimilation System (CLDAS) to directly backtrack high-resolution, high-quality land assimilation products. To address this issue, this paper proposes a deep learning model named UNET_DCA, [...] Read more.
Before 2008, China lacked high-coverage regional surface observation data, making it difficult for the China Meteorological Administration Land Data Assimilation System (CLDAS) to directly backtrack high-resolution, high-quality land assimilation products. To address this issue, this paper proposes a deep learning model named UNET_DCA, based on the UNET architecture, which incorporates a Dual Cross-Attention module (DCA) for multiscale feature fusion by introducing Channel Cross-Attention (CCA) and Spatial Cross-Attention (SCA) mechanisms. This model focuses on the near-surface 10-m wind field and achieves spatial downscaling from 6.25 km to 1 km. We conducted training and validation using data from 2020–2021, tested with data from 2019, and performed ablation experiments to validate the effectiveness of each module. We compared the results with traditional bilinear interpolation methods and the SNCA-CLDASSD model. The experimental results show that the UNET-based model outperforms SNCA-CLDASSD, indicating that the UNET-based model captures richer information in wind field downscaling compared to SNCA-CLDASSD, which relies on sequentially stacked CNN convolution modules. UNET_CCA and UNET_SCA, incorporating cross-attention mechanisms, outperform UNET without attention mechanisms. Furthermore, UNET_DCA, incorporating both Channel Cross-Attention and Spatial Cross-Attention mechanisms, outperforms UNET_CCA and UNET_SCA, which only incorporate one attention mechanism. UNET_DCA performs best on the RMSE, MAE, and COR metrics (0.40 m/s, 0.28 m/s, 0.93), while UNET_DCA_ars, incorporating more auxiliary information, performs best on the PSNR and SSIM metrics (29.006, 0.880). Evaluation across different methods indicates that the optimal model performs best in valleys, followed by mountains, and worst in plains; it performs worse during the day and better at night; and as wind speed levels increase, accuracy decreases. Overall, among various downscaling methods, UNET_DCA and UNET_DCA_ars effectively reconstruct the spatial details of wind fields, providing a deeper exploration for the inversion of high-resolution historical meteorological grid data. Full article
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<p>The figure on the left (<b>a</b>) illustrates the spatial arrangement of national meteorological stations (marked by red stars) and regional meteorological stations (depicted as green dots) within the study area. On the right (<b>b</b>), the figure displays the distribution of ground elevation across the research area, segmented into 49 distinct zones. <a href="#remotesensing-16-01867-t001" class="html-table">Table 1</a> provides a breakdown of the terrain types corresponding to each of these areas.</p>
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<p>The first column displays statistical histograms for Mean Absolute Error (MAE) and Correlation (COR) of regional site data; the second column shows the violin plots of MAE and COR for regional site data before data cleansing; the third column presents the violin plots of MAE and COR for regional site data after data cleansing.</p>
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<p>The architecture diagram of the UNET_DCA network model.</p>
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<p>The structure diagram of the Dual Interlaced Attention Module (DCA) consists of two modules: (<b>a</b>) the Channel Interlaced Attention Module and (<b>b</b>) the Spatial Interlaced Attention Module.</p>
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<p>Box plots of wind speed RMSE, MAE, and COR metrics based on station data as the Ground Truth for the downscaling results of each method.</p>
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<p>Visual comparison of downscaling results of various methods at 12:00 UTC on 24 April 2019.</p>
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<p>Daily variations of RMSE, MAE, COR, PSNR, and SSIM between downscaling wind speed results of each method and CLDAS3.0.</p>
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<p>Seasonal variations of RMSE, MAE, COR, PSNR, and SSIM between each method’s downscaling wind speed results and CLDAS3.0.</p>
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<p>The first row presents diagrams illustrating the diurnal variation in the accuracy of wind speed grade calculations derived from each downscaling method, with (<b>a</b>–<b>d</b>) corresponding to the four wind speed categories, respectively. The second row depicts the seasonal variation in the correctness of wind speed grade estimations achieved by the various downscaling techniques, where (<b>e</b>–<b>h</b>) respectively match the four distinct wind speed classes.</p>
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14 pages, 6060 KiB  
Article
Ferroptosis Altered microRNAs Expression in HT-1080 Fibrosarcoma Cells Based on Small RNA Sequencing and Bioinformatics Analysis
by Qian Zhang, Qiwen Wang, Haoxuan Ding, Caihong Hu and Jie Feng
Nutrients 2024, 16(6), 873; https://doi.org/10.3390/nu16060873 - 17 Mar 2024
Cited by 1 | Viewed by 1591
Abstract
Iron is an essential trace element in the human body. However, excess iron is harmful and may cause ferroptosis. The expression and role of microRNAs (miRNAs) in ferroptosis remain largely unknown. A model of ferroptosis induced by ferric ammonium citrate in HT-1080 cells [...] Read more.
Iron is an essential trace element in the human body. However, excess iron is harmful and may cause ferroptosis. The expression and role of microRNAs (miRNAs) in ferroptosis remain largely unknown. A model of ferroptosis induced by ferric ammonium citrate in HT-1080 cells was established in this study. The miRNAs expression profiles of the control and iron groups were obtained using small RNA sequencing and verified using qRT-PCR. A total of 1346 known miRNAs and 80 novel miRNAs were identified, including 12 up-regulated differentially expressed miRNAs (DE-miRNAs) and 16 down-regulated DE-miRNAs. SP1 was the most important upstream transcription factor regulating DE-miRNAs. The downstream target genes of DE-miRNAs were predicted based on miRDB, TargetScan, and miRBase databases, and 403 common target genes were screened. GO annotation and KEGG analysis revealed that the target genes were mainly involved in various biological processes and regulatory pathways, especially the MAPK signaling pathway and PI3K-Akt signaling pathway. Afterwards, a target genes network was constructed using STRING and Cytoscape, and the hub genes were compared with the ferroptosis database (FerrDb V2) to discover the hub genes related to ferroptosis. EGFR, GSK3B, PARP1, VCP, and SNCA were screened out. Furthermore, a DE-miRNAs-target genes network was constructed to explore key DE-miRNAs. hsa-miR-200c-3p, hsa-miR-26b-5p, and hsa-miR-7-5p were filtered out. Comprehensive bioinformatics analysis of miRNAs and its upstream and downstream regulation in ferroptosis in HT-1080 cells using small RNA sequencing is helpful for understanding the role of miRNAs in iron overload-related diseases and ferroptosis-targeted therapy for cancer. Full article
(This article belongs to the Section Micronutrients and Human Health)
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<p>The mechanisms of iron and miRNAs regulating ferroptosis. Ferroptosis is an iron-dependent non-apoptotic form of cell death and is regulated by iron metabolism, lipid metabolism, glutathione-GPX4 pathway, glutamate/cystine transport, and other processes. miRNAs influence ferroptosis by regulating the above processes. Cys—cystine; Glu—glutamate; GPX4—glutathione peroxidase 4; GSH—glutathione; GSSG—glutathione disulfide; miRNAs—microRNAs; PUFAs—polyunsaturated fatty acids; ROS—reactive oxygen species; TF—transferrin; and TfR1—transferrin receptor 1. By Figdraw.</p>
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<p>Ferroptosis cell model establishment. (<b>A</b>) Cell viability of HT-1080 cells treated with ferric ammonium citrate (FAC) for 24 h using CCK-8 assay. (<b>B</b>–<b>F</b>) Morphology of HT-1080 cells treated with FAC under different concentrations (0, 2, 4, 6, and 8 mM) for 24 h, scale bar = 100 μm. Data are presented as mean ± SD (<span class="html-italic">n</span> = 6). <sup>a, b, c, d</sup> Values of the bars without a common letter differ significantly at <span class="html-italic">p</span> &lt; 0.05.</p>
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<p>Differentially expressed miRNAs (DE-miRNAs) between the control group (CO) and iron group (IO). (<b>A</b>) Volcano plot. Red color represents significantly up-regulated miRNAs, and green color represents significantly down-regulated miRNAs (<span class="html-italic">p</span> adj  &lt; 0.05). Blue color represents miRNAs with no significance. (<b>B</b>) Hierarchical clustering analysis of relatively high expression miRNAs (red) and relatively low expression miRNAs (blue).</p>
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<p>Validation of DE-miRNAs in HT-1080 cells between the control group (CO) and the iron group (IO) using qRT-PCR. (<b>A</b>–<b>D</b>) Up-regulated DE-miRNAs: miR-3529-3p (<b>A</b>), miR-425-5p (<b>B</b>), miR-26b-5p (<b>C</b>), and miR-22-3p (<b>D</b>). (<b>E</b>–<b>H</b>) Down-regulated DE-miRNAs: miR-518c-5p (<b>E</b>), miR-16-2-3p (<b>F</b>), miR-125b-1-3p (<b>G</b>), and miR-744-5p (<b>H</b>). Data are represented as the mean ± SD (<span class="html-italic">n</span> = 3), * <span class="html-italic">p</span>  &lt; 0.05, ** <span class="html-italic">p</span>  &lt; 0.01; ns, not significant.</p>
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<p>Predicted transcription factors (TFs) of DE-miRNAs. EGR1—early growth response 1; FOXO1—forkhead box O1; MEF2A—myocyte enhancer factor 2A; POU2F1—POU class 2 homeobox 1; RREB1—Ras-responsive element binding protein 1, SP1—Sp1 transcription factor; SP4—Sp4 transcription factor; TAL1—basic helix-loop-helix (bHLH) transcription factor 1; TCF3—transcription factor 3; and ZFP161—zinc finger protein 161.</p>
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<p>The Venn diagram of the predicted target genes using miRDB, TargetScan, and miRBase databases.</p>
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<p>Gene ontology (GO) enrichment analysis of target genes. (<b>A</b>) Bar plot. (<b>B</b>) Scatter plot. The diameter of a point represents the number of target genes enriched in a specific item, and the adjusted <span class="html-italic">p</span>-value represents the degree of enrichment.</p>
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<p>Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of target genes. (<b>A</b>) Bar plot. (<b>B</b>) Scatter plot. The diameter of a point represents the number of target genes enriched in a specific item, and the adjusted <span class="html-italic">p</span>-value represents the degree of enrichment.</p>
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<p>PPI network of hub genes. Red indicates a higher degree of nodes in the PPI network.</p>
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<p>Network of interaction between DE-miRNAs and target genes via Cytoscape. Red color represents up-regulated DE-miRNAs, green color represents down-regulated DE-miRNAs, and blue color represents target genes.</p>
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16 pages, 1600 KiB  
Article
Peripheral Upregulation of Parkinson’s Disease-Associated Genes Encoding α-Synuclein, β-Glucocerebrosidase, and Ceramide Glucosyltransferase in Major Depression
by Razvan-Marius Brazdis, Claudia von Zimmermann, Bernd Lenz, Johannes Kornhuber and Christiane Mühle
Int. J. Mol. Sci. 2024, 25(6), 3219; https://doi.org/10.3390/ijms25063219 - 12 Mar 2024
Viewed by 1158
Abstract
Due to the high comorbidity of Parkinson’s disease (PD) with major depressive disorder (MDD) and the involvement of sphingolipids in both conditions, we investigated the peripheral expression levels of three primarily PD-associated genes: α-synuclein (SNCA), lysosomal enzyme β-glucocerebrosidase (GBA1), [...] Read more.
Due to the high comorbidity of Parkinson’s disease (PD) with major depressive disorder (MDD) and the involvement of sphingolipids in both conditions, we investigated the peripheral expression levels of three primarily PD-associated genes: α-synuclein (SNCA), lysosomal enzyme β-glucocerebrosidase (GBA1), and UDP-glucose ceramide glucosyltransferase (UGCG) in a sex-balanced MDD cohort. Normalized gene expression was determined by quantitative PCR in patients suffering from MDD (unmedicated n = 63, medicated n = 66) and controls (remitted MDD n = 39, healthy subjects n = 61). We observed that expression levels of SNCA (p = 0.036), GBA1 (p = 0.014), and UGCG (p = 0.0002) were higher in currently depressed patients compared to controls and remitted patients, and expression of GBA1 and UGCG decreased in medicated patients during three weeks of therapy. Additionally, in subgroups, expression was positively correlated with the severity of depression and anxiety. Furthermore, we identified correlations between the gene expression levels and PD-related laboratory parameters. Our findings suggest that SNCA, GBA1, and UGCG analysis could be instrumental in the search for biomarkers of MDD and in understanding the overlapping pathological mechanisms underlying neuro-psychiatric diseases. Full article
(This article belongs to the Special Issue Molecular Research on Depression)
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<p>Peripheral gene expressions of <span class="html-italic">SNCA</span> (<b>a</b>), <span class="html-italic">GBA</span> (<b>b</b>), and <span class="html-italic">UGCG</span> (<b>c</b>) were significantly higher in patients with current MDE (combined unmedicated patients (PU) and medicated patients (PM)) at inclusion compared to unaffected individuals (combined remitted patients (PR) and healthy subjects (HC)). These levels remained for <span class="html-italic">SNCA</span> (<b>d</b>) but decreased between inclusion (T1) and follow-up (T2) after on average three weeks of treatment as usual for <span class="html-italic">GBA1</span> (<b>e</b>) and <span class="html-italic">UGCG</span> (<b>f</b>) in the group of initially medicated patients. Normalized gene expression relative to reference genes is shown on a logarithmic <span class="html-italic">y</span>-axis. The numbers of individuals are provided below the <span class="html-italic">x</span>-axis. <span class="html-italic">p</span>-values from Mann–Whitney U test (<b>a</b>–<b>c</b>) and Wilcoxon test for paired values (<b>d</b>–<b>f</b>). Box plots with median and interquartile range.</p>
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<p>Positive correlations between depression severity assessed by HAM-D (<b>a</b>–<b>c</b>), MADRS (<b>d</b>–<b>f</b>), and STAI trait (<b>g</b>–<b>i</b>) with peripheral gene expressions of <span class="html-italic">SNCA</span>, <span class="html-italic">GBA</span>, and <span class="html-italic">UGCG</span> in patients with remitted major depressive disorder (PR) separated in female (red dots) and male (blue dots) subgroups at inclusion. Linear regression line for the combined group with 95% confidence interval and statistics (Spearman correlation, in bold for <span class="html-italic">p</span> &lt; 0.05). Sex-stratified statistical data are in <a href="#ijms-25-03219-t003" class="html-table">Table 3</a>.</p>
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10 pages, 1252 KiB  
Article
A Cross-Sectional Study of Protein Changes Associated with Dementia in Non-Obese Weight Matched Women with and without Polycystic Ovary Syndrome
by Alexandra E. Butler, Abu Saleh Md Moin, Thozhukat Sathyapalan and Stephen L. Atkin
Int. J. Mol. Sci. 2024, 25(4), 2409; https://doi.org/10.3390/ijms25042409 - 18 Feb 2024
Viewed by 1583
Abstract
Dysregulated Alzheimer’s disease (AD)-associated protein expression is reported in polycystic ovary syndrome (PCOS), paralleling the expression reported in type 2 diabetes (T2D). We hypothesized, however, that these proteins would not differ between women with non-obese and non-insulin resistant PCOS compared to matched control [...] Read more.
Dysregulated Alzheimer’s disease (AD)-associated protein expression is reported in polycystic ovary syndrome (PCOS), paralleling the expression reported in type 2 diabetes (T2D). We hypothesized, however, that these proteins would not differ between women with non-obese and non-insulin resistant PCOS compared to matched control subjects. We measured plasma amyloid-related proteins levels (Amyloid-precursor protein (APP), alpha-synuclein (SNCA), amyloid P-component (APCS), Pappalysin (PAPPA), Microtubule-associated protein tau (MAPT), apolipoprotein E (apoE), apoE2, apoE3, apoE4, Serum amyloid A (SAA), Noggin (NOG) and apoA1) in weight and aged-matched non-obese PCOS (n = 24) and control (n = 24) women. Dementia-related proteins fibronectin (FN), FN1.3, FN1.4, Von Willebrand factor (VWF) and extracellular matrix protein 1 (ECM1) were also measured. Protein levels were determined by Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement. Only APCS differed between groups, being elevated in non-obese PCOS women (p = 0.03) relative to the non-obese control women. This differed markedly from the elevated APP, APCS, ApoE, FN, FN1.3, FN1.4 and VWF reported in obese women with PCOS. Non-obese, non-insulin resistant PCOS subjects have a lower AD-associated protein pattern risk profile versus obese insulin resistant PCOS women, and are not dissimilar to non-obese controls, indicating that lifestyle management to maintain optimal body weight could be beneficial to reduce the long-term AD-risk in women with PCOS. Full article
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<p>Demographic and biochemical correlations with plasma amyloid-related proteins levels in polycystic ovary syndrome (PCOS) and control subjects; amyloid P-component (APCS) and apolipoprotein E (apoE) with body mass index (BMI), insulin resistance (HOMA-IR) and testosterone in weight and aged-matched non-obese PCOS (<span class="html-italic">n</span> = 24) and control (<span class="html-italic">n</span> = 24) women. (<b>A</b>), positive correlation of APCS with BMI (<span class="html-italic">p</span> = 0.003); (<b>B</b>), positive correlation of ApoE with BMI (<span class="html-italic">p</span> = 0.02); (<b>C</b>), positive correlation of ApoE with HOMA-IR (<span class="html-italic">p</span> = 0.04); (<b>D</b>), negative correlation of APCS with testosterone (<span class="html-italic">p</span> = 0.02).</p>
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<p>Correlations of Alzheimer’s-related proteins with interleukin 6 (IL6) and heat shock proteins in polycystic ovary syndrome (PCOS) and control subjects. APP correlated positively with IL6 in PCOS (<span class="html-italic">p</span> = 0.04) (<b>A</b>); ApoE correlated negatively with IL6 in PCOS (<span class="html-italic">p</span> = 0.04) (<b>B</b>); in both PCOS (<span class="html-italic">p</span> = 0.0006) and control women (<span class="html-italic">p</span> = 0.04) APP corelated positively with heat shock protein 90 (HSP90AA1) (<b>C</b>); SNCA correlated positively with HSP90AA1 (<span class="html-italic">p</span> = 0.01) (<b>D</b>), APP correlated positively with heat shock protein 60 (HSPD1: <span class="html-italic">p</span> = 0.0006) (<b>E</b>); SNCA correlated positively with HSPD1 (<span class="html-italic">p</span> = 0.004) (<b>F</b>). Controls: black open circles; PCOS: blue squares.</p>
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20 pages, 973 KiB  
Review
Dementia with Lewy Bodies: Genomics, Transcriptomics, and Its Future with Data Science
by Thomas R. Goddard, Keeley J. Brookes, Riddhi Sharma, Armaghan Moemeni and Anto P. Rajkumar
Cells 2024, 13(3), 223; https://doi.org/10.3390/cells13030223 - 25 Jan 2024
Viewed by 1894
Abstract
Dementia with Lewy bodies (DLB) is a significant public health issue. It is the second most common neurodegenerative dementia and presents with severe neuropsychiatric symptoms. Genomic and transcriptomic analyses have provided some insight into disease pathology. Variants within SNCA, GBA, APOE [...] Read more.
Dementia with Lewy bodies (DLB) is a significant public health issue. It is the second most common neurodegenerative dementia and presents with severe neuropsychiatric symptoms. Genomic and transcriptomic analyses have provided some insight into disease pathology. Variants within SNCA, GBA, APOE, SNCB, and MAPT have been shown to be associated with DLB in repeated genomic studies. Transcriptomic analysis, conducted predominantly on candidate genes, has identified signatures of synuclein aggregation, protein degradation, amyloid deposition, neuroinflammation, mitochondrial dysfunction, and the upregulation of heat-shock proteins in DLB. Yet, the understanding of DLB molecular pathology is incomplete. This precipitates the current clinical position whereby there are no available disease-modifying treatments or blood-based diagnostic biomarkers. Data science methods have the potential to improve disease understanding, optimising therapeutic intervention and drug development, to reduce disease burden. Genomic prediction will facilitate the early identification of cases and the timely application of future disease-modifying treatments. Transcript-level analyses across the entire transcriptome and machine learning analysis of multi-omic data will uncover novel signatures that may provide clues to DLB pathology and improve drug development. This review will discuss the current genomic and transcriptomic understanding of DLB, highlight gaps in the literature, and describe data science methods that may advance the field. Full article
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<p>An overview of the dysfunctional pathways within DLB, both intracellular and extracellular, that have been identified by transcriptomic analysis. The gene expression changes of relevant genes and transcripts have been included to show how upregulation and downregulation may play into the dysfunction of each pathway. Green arrows within the transcriptomic changes indicate an increase in expression. Red arrows within the transcriptomic changes indicate a decrease in expression. Green arrows combined with red arrows indicate that expression can be upregulated or downregulated, depending on the brain region. Created with <a href="https://app.biorender.com" target="_blank">https://app.biorender.com</a> (accessed on 14 December 2023).</p>
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13 pages, 2765 KiB  
Article
A Cross-Sectional Study of Alzheimer-Related Proteins in Women with Polycystic Ovary Syndrome
by Alexandra E. Butler, Abu Saleh Md Moin, Thozhukat Sathyapalan and Stephen L. Atkin
Int. J. Mol. Sci. 2024, 25(2), 1158; https://doi.org/10.3390/ijms25021158 - 18 Jan 2024
Cited by 4 | Viewed by 1864
Abstract
Polycystic ovary syndrome (PCOS) is the most common endocrine condition in women of reproductive age, and several risk factors found in PCOS are associated with an increased risk of Alzheimer’s disease (AD). Proteins increased in AD have been reported to include fibronectin (FN) [...] Read more.
Polycystic ovary syndrome (PCOS) is the most common endocrine condition in women of reproductive age, and several risk factors found in PCOS are associated with an increased risk of Alzheimer’s disease (AD). Proteins increased in AD have been reported to include fibronectin (FN) fragments 3 and 4 (FN1.3 and FN1.4, respectively) and ApoE. We hypothesized that Alzheimer-related proteins would be dysregulated in PCOS because of associated insulin resistance and obesity. In this comparative cross-sectional analysis, aptamer-based SomaScan proteomic analysis for the detection of plasma Alzheimer-related proteins was undertaken in a PCOS biobank of 143 women with PCOS and 97 control women. Amyloid precursor protein (APP) (p < 0.05) and amyloid P-component (APCS) (p < 0.001) were elevated in PCOS, while alpha-synuclein (SNCA) (p < 0.05) was reduced in PCOS. Associations with protective heat shock proteins (HSPs) showed that SNCA positively correlated with HSP90 (p < 0.0001) and HSP60 (p < 0.0001) in both the PCOS and control women. Correlations with markers of inflammation showed that APCS correlated with interleukin 6 (IL6) (p = 0.04), while Apolipoprotein (Apo) E3 correlated with TNF-alpha (p = 0.02). FN, FN1.3, FN1.4 and ApoE were all elevated significantly (p < 0.05). An AD-associated protein pattern with elevated FN, FN1.3, FN1.4 and ApoE was found in PCOS, in addition to elevated APP and reduced SNCA, which was the same as reported for type 2 diabetes (T2D) with, additionally, an elevation in APCS. With the AD biomarker pattern in PCOS being very similar to that in T2D, where there is an association between AD and T2D, this suggests that larger prospective cohort studies are needed in women with PCOS to determine if there is a causal association with AD. Full article
(This article belongs to the Section Molecular Pathology, Diagnostics, and Therapeutics)
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<p>A schematic to illustrate the biology of amyloid-beta (Aβ)-induced neuronal death. The enzyme secretases act on amyloid-beta precursor protein (APP) to cleave the protein into three fragments. Sequential cleavage via β-secretases and γ-secretases produces the amyloid-beta (Aβ) peptide fragments. No Aβ is formed if the APP is cleaved by α-secretase. Aβ undergoes oligomerization with the help of Apolipoprotein E (ApoE). Aβ oligomers form senile (neuritic) plaque. Aβ oligomers, in association with ApoE and microtubule-associated protein tau (MAPT), form neurofibrillary tangles that eventually lead to neuron death. Aβ clearance from the brain is positively regulated by ApoE proteins (ApoE2, ApoE3) and negatively regulated by ApoE and ApoE4. Aβ degradation is also regulated by the serum amyloid P component (APCS). Upward green arrows indicate the Alzheimer-related proteins upregulated in PCOS (APP, APCS and ApoE); downward red arrows indicate the Alzheimer-related protein (SNCA) that is downregulated in PCOS.</p>
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<p>Alzheimer-related plasma protein levels in women with and without polycystic ovary syndrome (PCOS). APP (<span class="html-italic">p</span> &lt; 0.05) (<b>A</b>); APCS (<span class="html-italic">p</span> &lt; 0.001) (<b>B</b>); and ApoE (<span class="html-italic">p</span> &lt; 0.01) (<b>C</b>) were elevated in PCOS, while SNCA (<span class="html-italic">p</span> &lt; 0.05) (<b>D</b>) was reduced in PCOS. <sup>#</sup> <span class="html-italic">p</span> &lt; 0.05; * <span class="html-italic">p</span> &lt; 0.01; **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Correlations of Alzheimer-related proteins that differed between women with and without polycystic ovary syndrome (PCOS). SNCA correlated positively with HSP90AA1 (HSP90) (<b>A</b>) and HSPD1 (HSP60) (<b>B</b>) in both PCOS and control women (<span class="html-italic">p</span> &lt; 0.0001). APCS correlated positively with IL6 (<span class="html-italic">p</span> = 0.04) (<b>C</b>), and ApoE correlated positively with TNFa (<span class="html-italic">p</span> = 0.02) (<b>D</b>) only in women with PCOS. Controls: black open circles; PCOS: blue squares.</p>
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18 pages, 1208 KiB  
Article
Application of OpenArray Technology to Assess Changes in the Expression of Functionally Significant Genes in the Substantia Nigra of Mice in a Model of Parkinson’s Disease
by Dmitry Troshev, Anna Kolacheva, Ekaterina Pavlova, Victor Blokhin and Michael Ugrumov
Genes 2023, 14(12), 2202; https://doi.org/10.3390/genes14122202 - 12 Dec 2023
Viewed by 1705
Abstract
Studying the molecular mechanisms of the pathogenesis of Parkinson’s disease (PD) is critical to improve PD treatment. We used OpenArray technology to assess gene expression in the substantia nigra (SN) cells of mice in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD and in controls. [...] Read more.
Studying the molecular mechanisms of the pathogenesis of Parkinson’s disease (PD) is critical to improve PD treatment. We used OpenArray technology to assess gene expression in the substantia nigra (SN) cells of mice in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD and in controls. Among the 11 housekeeping genes tested, Rps27a was taken as the reference gene due to its most stable expression in normal and experimental conditions. From 101 genes encoding functionally significant proteins of nigrostriatal dopaminergic neurons, 57 highly expressed genes were selected to assess their expressions in the PD model and in the controls. The expressions of Th, Ddc, Maoa, Comt, Slc6a3, Slc18a2, Drd2, and Nr4a2 decreased in the experiment compared to the control, indicating decreases in the synthesis, degradation, and transport of dopamine and the impaired autoregulation of dopaminergic neurons. The expressions of Tubb3, Map2, Syn1, Syt1, Rab7, Sod1, Cib1, Gpx1, Psmd4, Ubb, Usp47, and Ctsb genes were also decreased in the MPTP-treated mice, indicating impairments of axonal and vesicular transport and abnormal functioning of the antioxidant and ubiquitin-proteasome systems in the SN. The detected decreases in the expressions of Snca, Nsf, Dnm1l, and Keap1 may serve to reduce pathological protein aggregation, increase dopamine release in the striatum, prevent mitophagy, and restore the redox status of SN cells. Full article
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<p>Concentrations of dopamine (DA) (<b>A</b>), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 3-methoxytyramine (3-MT) (<b>B</b>) in the striatum in a mouse model of Parkinson’s disease. The Shapiro–Wilk test was used to assess the normal distribution of the groups. Statistics indicate significance via the unpaired <span class="html-italic">t</span> -test (* <span class="html-italic">p</span> ≤ 0.05 compared with the control group). Data are presented as mean ± SEM; <span class="html-italic">n</span> = 8 for each group.</p>
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<p>Changes in the expressions of genes encoding dopamine-synthesizing enzymes (<span class="html-italic">Th</span> and <span class="html-italic">Ddc</span>), dopamine-degrading enzymes (<span class="html-italic">Maoa</span> and <span class="html-italic">Comt</span>), dopamine transporters (<span class="html-italic">Slc6a3</span> and <span class="html-italic">Slc18a2</span>), dopamine receptor (<span class="html-italic">Drd2</span>), and transcription factor Nurr1 (<span class="html-italic">Nr4a2</span>) in the substantia nigra in a mouse model of Parkinson’s disease. The Shapiro–Wilk test was used to assess the normal distribution of the groups. Statistics indicate significance by the unpaired <span class="html-italic">t</span>-test (* <span class="html-italic">p</span> ≤ 0.05 compared with the control group). Data are presented as mean ± SEM; <span class="html-italic">n</span> = 8 for each group.</p>
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<p>Changes in the expressions of genes for proteins associated with axonal transport (<span class="html-italic">Tubb3</span> and <span class="html-italic">Map2</span>) and the vesicular cycle (<span class="html-italic">Snca</span>, <span class="html-italic">Syn1</span>, <span class="html-italic">Syt1</span>, <span class="html-italic">Rab7</span>, <span class="html-italic">Nsf</span>, and <span class="html-italic">Dnm1l</span>) in the substantia nigra in a mouse model of Parkinson’s disease. The Shapiro–Wilk test was used to assess the normal distribution of the groups. Statistics indicate significance by the unpaired <span class="html-italic">t</span>-test (* <span class="html-italic">p</span> ≤ 0.05 compared with the control group). Data are presented as mean ± SEM. <span class="html-italic">n</span> = 8 for each group.</p>
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<p>Changes in the expressions of genes encoding proteins of the antioxidant system (<span class="html-italic">Sod1</span> and <span class="html-italic">Gpx1</span>), transcription factors (<span class="html-italic">Keap1</span>), calcium-binding proteins (<span class="html-italic">Calb1</span> and <span class="html-italic">Cib1</span>) and proteins of the ubiquitin-proteasome system (<span class="html-italic">Psmd4</span>, <span class="html-italic">Ubb</span>, <span class="html-italic">Usp47</span>, and <span class="html-italic">Ctsb</span>) in the substantia nigra in a mouse model of Parkinson’s disease. The Shapiro–Wilk test was used to assess the normal distribution of the groups. Statistics indicate significance using unpaired <span class="html-italic">t</span> test (* <span class="html-italic">p</span> ≤ 0.05 vs. control group). Data are presented as mean ± SEM; <span class="html-italic">n</span> = 8 for each group.</p>
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14 pages, 2281 KiB  
Article
Early Effects of Alpha-Synuclein Depletion by Pan-Neuronal Inactivation of Encoding Gene on Electroencephalogram Coherence between Different Brain Regions in Mice
by Vasily Vorobyov, Alexander Deev, Olga Morozova, Zoya Oganesyan, Anastasia M. Krayushkina, Tamara A. Ivanova and Kirill Chaprov
Biomedicines 2023, 11(12), 3282; https://doi.org/10.3390/biomedicines11123282 - 12 Dec 2023
Viewed by 1207
Abstract
Inactivation of the Snca gene in young mice by chronic injections of tamoxifen (TAM), a selective estrogen receptor modifier, has been shown to decrease the level of alpha-synuclein, a key peptide in the pathogenesis of Parkinson’s disease. In young mice, different time courses [...] Read more.
Inactivation of the Snca gene in young mice by chronic injections of tamoxifen (TAM), a selective estrogen receptor modifier, has been shown to decrease the level of alpha-synuclein, a key peptide in the pathogenesis of Parkinson’s disease. In young mice, different time courses of the effect were observed in different brain areas, meaning associated disturbances in the intracerebral relations, namely in brain function after TAM-induced synucleinopathy. Methods: We analyzed electroencephalogram (EEG) coherence (“functional connectivity”) between the cortex (MC), putamen (Pt), and dopamine-producing brain regions (ventral tegmental area, VTA, and substantia nigra, SN) in two groups of two-month-old male mice. We compared EEG coherences in the conditional knockout Sncaflox/flox mice with those in their genetic background (C57Bl6J) one, two, and three months after chronic (for five days) intraperitoneal injections of TAM or the vehicle (corn oil). The EEG coherences in the TAM-treated group were compared with those in the alpha-synuclein knockout mice. Results: A significant suppression of EEG coherence in the TAM-treated mice versus the vehicle group was observed in all inter-structural relations, with the exception of MC-VTA at one and three months and VTA-SN at two months after the injections. Suppressive changes in EEG coherence were observed in the alpha-synuclein knockout mice as well; the changes were similar to those in TAM-treated mice three months after treatment. Conclusion: our data demonstrate a combined time-dependent suppressive effect induced by TAM on intracerebral EEG coherence. Full article
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<p>Images of coronal sections of the mouse brain demonstrate coagulated tissues at the position of electrode tips (red dashed ellipses) in the ventral tegmental area (<b>A</b>) and substantia nigra (<b>B</b>). Dopaminergic neurons (green signal) were immunostained with antibodies against tyrosine hydroxylase, while DAPI-stained nuclei are denoted by blue signals. Scale bar is 500 μm.</p>
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<p>Representative patterns in 12 s fragments of baseline EEG in wakeful and behaviorally active 3-month-old mice intraperitoneally injected at the age of 2 months with the vehicle (corn oil, (<b>A</b>)) or tamoxifen (0.5 mmol/kg, (<b>B</b>)). EEGs were recorded from the motor cortex (MC), putamen (Pt), ventral tegmental area (VTA), and substantia nigra (SN). Time calibration is 1 s, amplitude calibration is 100 mkV.</p>
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<p>Inter-structural baseline EEG coherences in 3-month-old mice that were averaged for 10-min intervals one month after intraperitoneal injection of tamoxifen (TAM, 0.5 mmol/kg) or the vehicle (black and grey lines, respectively). MC, Pt, VTA, and SN are the motor cortex, putamen, ventral tegmental area, and substantia nigra (SN), respectively. Inter-structural coherence is denoted on the plates as MC-Pt (<b>A</b>); MC-VTA (<b>B</b>); MC-SN (<b>C</b>); Pt-VTA (<b>D</b>); Pt-SN (<b>E</b>), and VTA-SN (<b>F</b>). Ordinate is the average value of EEG coherence in each of the 1-hertz (Hz) bins within the analyzed 30-Hz frequency range denoted on abscissa. Five vertical lines separate “classical” EEG frequency bands (from left to right: delta 1, delta 2, theta, alpha, beta 1, and beta 2, respectively). Black and red dashed lines demonstrate maximal (1.0) and middle (0.5) coherence values, respectively.</p>
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<p>Inter-structural baseline EEG coherences that were averaged for 30 min 1, 2, and 3 months ((<b>A</b>), (<b>B</b>), and (<b>C</b>), respectively) after injection of tamoxifen (TAM, 0.5 mmol/kg) or the vehicle (grey and blue bars, respectively) in comparison with those in control and alpha-synuclein knockout mice ((<b>D</b>), blue and black bars, respectively). MC, Pt, VTA, and SN are the motor cortex, putamen, ventral tegmental area, and substantia nigra (SN), respectively. Inter-structural coherence is denoted on the plates as MC-Pt (<b>a</b>); MC-VTA (<b>b</b>); MC-SN (<b>c</b>); Pt-VTA (<b>d</b>); Pt-SN (<b>e</b>), and VTA-SN (<b>f</b>). Ordinate is the average value of EEG coherence in “classical” EEG frequency bands denoted on abscissa (from left to right: delta 1, delta 2, theta, alpha, beta 1, and beta 2, respectively). Black and red dashed lines demonstrate maximal (1.0) and middle (0.5) coherence values, respectively. Star symbols denote significant differences of coherence in EEG frequency bands between TAM- and vehicle-treated mice (<b>A</b>–<b>C</b>) and between alpha-synuclein knockout and control mice (<b>D</b>), where *, **, and *** denote <span class="html-italic">p</span> &lt; 0.05, <span class="html-italic">p</span> &lt; 0.01, and <span class="html-italic">p</span> &lt; 0.001, respectively. (The results of two-way ANOVA analysis of coherences in different frequency bands are seen in <a href="#app1-biomedicines-11-03282" class="html-app">Appendix A</a>).</p>
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<p>Dorsal striatum concentrations of (<b>A</b>) dopamine (DA), (<b>B</b>) its metabolites of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) presented as their relative ratios, and (<b>C</b>) 5-Hydroxytryptamine (5-HT, serotonin) one, two, and three months (abscissa) after TAM (grey bars) and one and three months after vehicle (open bars) injections. The normalized expression levels of mRNA for alpha-, beta-, and gamma- synucleins in the prefrontal cortex in different intervals after TAM injections are presented on (<b>D</b>), (<b>E</b>), and (<b>F</b>) plates, respectively. GAPDH gene expression was used as a reference value for normalization.</p>
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26 pages, 35876 KiB  
Article
The Construction and Validation of a Novel Ferroptosis-Related Gene Signature in Parkinson’s Disease
by Tingting Liu, Haojie Wu and Jianshe Wei
Int. J. Mol. Sci. 2023, 24(24), 17203; https://doi.org/10.3390/ijms242417203 - 6 Dec 2023
Cited by 2 | Viewed by 1935
Abstract
As a newly discovered regulated cell death mode, ferroptosis is associated with the development of Parkinson’s disease (PD) and has attracted much attention. Nonetheless, the relationship between ferroptosis and PD pathogenesis remains unclear. The GSE8397 dataset includes GPL96 and GPL97 platforms. The differential [...] Read more.
As a newly discovered regulated cell death mode, ferroptosis is associated with the development of Parkinson’s disease (PD) and has attracted much attention. Nonetheless, the relationship between ferroptosis and PD pathogenesis remains unclear. The GSE8397 dataset includes GPL96 and GPL97 platforms. The differential genes were analyzed by immune infiltration and Gene Set Enrichment Analysis (GSEA) (p < 0.05), and differential multiple |logFC| > 1 and weighted gene coexpression network analysis (WGCNA) were used to screen differential expression genes (DEGs). The intersection with 368 ferroptosis-related genes (FRGs) was conducted for gene ontology/Kyoto encyclopedia of gene and genome (GO/KEGG) enrichment analysis, gene expression analysis, correlation analysis, single-cell sequencing analysis, and prognosis analysis (area under the curve, AUC) and to predict relevant miRNAs and construct network diagrams using Cytoscape. The intersection genes of differentially expressed ferroptosis-related genes (DEFRGs) and mitochondrial dysfunction genes were validated in the substantia nigra of MPTP-induced PD mice models by Western blotting and immunohistochemistry, and the protein-binding pocket was predicted using the DoGSiteScorer database. According to the results, the estimated scores were positively correlated with the stromal scores or immune scores in the GPL96 and GPL97 platforms. In the GPL96 platform, the GSEA showed that differential genes were mainly involved in the GnRH signaling pathway, B cell receptor signaling pathway, inositol phosphate metabolism, etc. In the GPL97 platform, the GSEA showed that differential genes were mainly involved in the ubiquitin-mediated proteolysis, axon guidance, Wnt signaling pathway, MAPK signaling pathway, etc. We obtained 26 DEFRGs, including 12 up-regulated genes and 14 down-regulated genes, with good correlation. The area under the prognostic analysis curve (AUC > 0.700) showed a good prognostic ability. We found that they were enriched in different neuronal cells, oligodendrocytes, astrocytes, oligodendrocyte precursor cells, and microglial cells, and their expression scores were positively correlated, and selected genes with an AUC curve ≥0.9 were used to predict miRNA, including miR-214/761/3619-5p, miR-203, miR-204/204b/211, miR-128/128ab, miR-199ab-5p, etc. For the differentially expressed ferroptosis–mitochondrial dysfunction-related genes (DEF-MDRGs) (AR, ISCU, SNCA, and PDK4), in the substantia nigra of mice, compared with the Saline group, the expression of AR and ISCU was decreased (p < 0.05), and the expression of α-Syn and PDK4 was increased (p < 0.05) in the MPTP group. Therapeutic drugs that target SNCA include ABBV-0805, Prasinezumab, Cinpanemab, and Gardenin A. The results of this study suggest that cellular DEF-MDRGs might play an important role in PD. AR, ISCU, SNCA, and PDK4 have the potential to be specific biomarkers for the early diagnosis of PD. Full article
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<p>Gene chip data information. (<b>A</b>) PD sample information from the GPL96 platform in the GSE8397 dataset. (<b>B</b>) Sample information from the GPL96 platform in the GSE8397 dataset. (<b>C</b>) PCA and mean-variance trend in PD compared with the normal controls of GPL96 platform. The blue line is constant variance approximation. (<b>D</b>) PCA and mean-variance trend in PD compared with the normal controls of GPL97 platform. The blue line is constant variance approximation. (<b>E</b>) Volcano map of differential genes. Blue represents low expression and red represents high expression. <span class="html-italic">p</span>-value &lt; 0.05.</p>
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<p>Immune infiltration analysis and GSEA of differential genes. (<b>A</b>) Heatmap of immune infiltration analysis in the GPL96 platform. (<b>B</b>) Heatmap of immune infiltration analysis in the GPL97 platform. (<b>C</b>) The correlation between the estimated scores and the stromal scores or immune scores in the GPL96 platform. (<b>D</b>) The correlation between the estimated scores and the stromal scores or immune scores in the GPL97 platform. (<b>E</b>) Boxplot of differentially expressed immune cells in the GPL96 platform. (<b>F</b>) Boxplot of differentially expressed immune cells in the GPL97 platform. (<b>G</b>) GSEA enrichment analysis of the GPL96 platform. (<b>H</b>) GSEA enrichment analysis of the GPL97 platform. Compared with normal controls, * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>WGCNA analysis of GPL96 platform. (<b>A</b>) Cluster analysis of samples on GPL96 platform. (<b>B</b>) Scale independence and soft threshold of GPL96 platform, we chose power = 16. The ordinate represents the average connectivity number of all nodes, and most nodes have a low connectivity, so the lower the average connectivity number, the better. (<b>C</b>) Cluster analysis of genes on GPL96 platform. (<b>D</b>) Eight modules were obtained by gene clustering, and the correlation of the modules was analyzed. (<b>E</b>) Eigengene adjacency heatmap. (<b>F</b>) Relationship between gene traits and gene module members, the scatterplot of gene traits in brown module was positively correlated with gene module members. (<b>G</b>) PPI analysis of hub genes in the Brown module.</p>
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<p>Correlation analysis of differentially expressed genes and ferroptosis-related genes. (<b>A</b>) Venn diagram of DEGs and FRGs showed that there were 3 overlapping genes between GPL96 platform, GPL97 platform, and FRGs, GPL96 and FRGs intermingled 10 genes separately, and GPL97 and FRGs intermingled 3 genes separately. (<b>B</b>) In Venn diagram, 8 genes and 2 genes were overlapping between ferroptosis and GPL96 and GPL97 platform of WGCNA, respectively. (<b>C</b>) The gene is located on the chromosome. (<b>D</b>) DEFRGs in GPL96 platform gene expression in PD compared with normal controls. (<b>E</b>) DEFRGs in GPL97 platform gene expression in PD compared with normal controls. (<b>F</b>) Gene expression differences in the GPL96 and GPL97 platform of WGCNA. (<b>G</b>) Correlation of DEFRGs in GPL96 platform. (<b>H</b>) Correlation of DEFRGs in GPL97 platform. Red represents positive correlation, and blue represents negative correlation. The stronger the inter-gene correlation, the thicker the line segment.</p>
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<p>Differential gene analysis. (<b>A</b>) Gene heat map from GPL96 platform. (<b>B</b>) Gene heat map from GPL97 platform. Red represents high expression, and blue represents low expression. (<b>C</b>,<b>D</b>) Biological function and KEGG enrichment analysis, BP: GO:0060249: <span class="html-italic">HSPB1/LAMP2/PDK4/TF/TYRO3/YAP1</span>; GO:0071248: <span class="html-italic">MT1G/SNCA/TF/ALOX15/MAPK1</span>; GO:0071241: <span class="html-italic">MT1G/SNCA/TF/ALOX15/MAPK1</span>; CC: GO:0031092: <span class="html-italic">SNCA/CYB5R1</span>; GO:0005770: <span class="html-italic">LAMP2/TF/GFRA1/MAPK1</span>; GO:0031091: <span class="html-italic">SNCA/CYB5R1</span>; MF: GO:0008198: <span class="html-italic">SNCA/TF/CDO1/ISCU</span>; GO:0005506: <span class="html-italic">SNCA/TF/ALOX15/CDO1/ISCU</span>; GO:0051213: <span class="html-italic">ALOX15/KDM5A/CDO1</span>; KEGG: hsa04216: <span class="html-italic">CP/TF/ALOX15</span>; hsa05215: <span class="html-italic">GSK3B/MAPK1/AR</span>; hsa04550: <span class="html-italic">GSK3B/LIFR/MAPK1</span>.</p>
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<p>Diagnostic value of DEFRGs in (<b>A</b>) GPL96 platform, (<b>B</b>) GPL97 platform, and (<b>C</b>) combined gene analysis. ROC curves of <span class="html-italic">BEX1</span>, <span class="html-italic">CIRBP</span>, <span class="html-italic">CP</span>, <span class="html-italic">DNAJB6</span>, <span class="html-italic">GCH1</span>, <span class="html-italic">HSPB1</span>, <span class="html-italic">LAMP2</span>, <span class="html-italic">MT1G</span>, <span class="html-italic">TF</span>, <span class="html-italic">YTHDC2</span>, <span class="html-italic">GFRA1</span>, <span class="html-italic">GSK3B</span>, <span class="html-italic">LIFR</span>, <span class="html-italic">ADAM23</span>, <span class="html-italic">PDK4</span>, and <span class="html-italic">SNCA</span>.</p>
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<p>Single-cell sequencing analysis of DEFRGs. (<b>A</b>) Single-cell sequencing was used to analyze the expression of DEFRGs in the brain. (<b>B</b>) Expression Z-scores of DEFRGs in 44 cells in the brain.</p>
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<p>Coexpression network of diagnostic genes and target miRNAs. Red ellipses represent diagnostic genes, green quadrangles represent target miRNAs, pink triangle represent transcript regions, and blue quadrangles represent seed types.</p>
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<p>Validity verification of DEF-MDRGs. (<b>A</b>) Validation of DEF-MDRGs by Western blotting. (<b>B</b>) Statistical plots of AR, ISCU, SNCA, and PDK4. (<b>C</b>) Validation of DEF-MDRGs by immunohistochemistry. (<b>D</b>) Proportion of positive degree of differentially expressed ferroptosis–mitochondrial dysfunction-related proteins. Compared with the Saline group, * means <span class="html-italic">p</span> &lt; 0.05, ** means <span class="html-italic">p</span> &lt; 0.01, and *** means <span class="html-italic">p</span> &lt; 0.001, n = 3.</p>
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<p>Validation of <span class="html-italic">SNCA</span> expression level in GSE49036 dataset (<b>A</b>) sample information of GSE49036 dataset. (<b>B</b>) A total of 3803 genes overlapped between stage 5–6 and stage 0. (<b>C</b>) The pathological stage of α-Syn in 28 samples was divided into Braak α-Syn stage 0 (Control); Braak α-Syn stage 1–2 (incidental Lewy body disease); Braak α-Syn 3–4 and Braak α-Syn stages 5–6 (PD), Orange represents control, red represents Braak α-Syn stage 1–2, blue represents Braak α-Syn 3–4, green represents Braak α-Syn stages 5–6. (<b>D</b>) Compared with stage 0, the expression differences of α-Syn in the 5 SNCA gene samples were more significant with the aggravation of pathological process, especially in stage 5–6.</p>
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<p>Prediction of protein-binding pockets with higher drug-binding scores, including (<b>A</b>) PDK4-2zkj, (<b>B</b>) SNCA-1xq8, (<b>C</b>) ISCU-7c8m, and (<b>D</b>) AR-1r4i.</p>
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<p>The flow chart of this study. DEGs, differentially expressed genes; FRGs, ferroptosis-related genes; DEFRGs, differentially expressed ferroptosis-related genes; GSEA, gene set enrichment analysis; GO, gene ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; MDRGs, mitochondrial dysfunction-related genes; DEF-MDRGs, differentially expressed ferroptosis–mitochondrial dysfunction-related genes.</p>
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18 pages, 3984 KiB  
Review
Involvement of Mitochondria in Parkinson’s Disease
by Chi-Jing Choong and Hideki Mochizuki
Int. J. Mol. Sci. 2023, 24(23), 17027; https://doi.org/10.3390/ijms242317027 - 1 Dec 2023
Cited by 6 | Viewed by 2505
Abstract
Mitochondrial dysregulation, such as mitochondrial complex I deficiency, increased oxidative stress, perturbation of mitochondrial dynamics and mitophagy, has long been implicated in the pathogenesis of PD. Initiating from the observation that mitochondrial toxins cause PD-like symptoms and mitochondrial DNA mutations are associated with [...] Read more.
Mitochondrial dysregulation, such as mitochondrial complex I deficiency, increased oxidative stress, perturbation of mitochondrial dynamics and mitophagy, has long been implicated in the pathogenesis of PD. Initiating from the observation that mitochondrial toxins cause PD-like symptoms and mitochondrial DNA mutations are associated with increased risk of PD, many mutated genes linked to familial forms of PD, including PRKN, PINK1, DJ-1 and SNCA, have also been found to affect the mitochondrial features. Recent research has uncovered a much more complex involvement of mitochondria in PD. Disruption of mitochondrial quality control coupled with abnormal secretion of mitochondrial contents to dispose damaged organelles may play a role in the pathogenesis of PD. Furthermore, due to its bacterial ancestry, circulating mitochondrial DNAs can function as damage-associated molecular patterns eliciting inflammatory response. In this review, we summarize and discuss the connection between mitochondrial dysfunction and PD, highlighting the molecular triggers of the disease process, the intra- and extracellular roles of mitochondria in PD as well as the therapeutic potential of mitochondrial transplantation. Full article
(This article belongs to the Special Issue Recent Molecular Research of Parkinson's Disease)
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Figure 1

Figure 1
<p>Extracellular mitochondria in PD. (a) In rotenone-induced mitochondrial impairment and parkin-deficient models, damaged mitochondria were extruded from cells in free form or membrane-surrounded vesicles. (b) In a 6-OHDA rodent model of PD, dopaminergic neurons showed accumulation of damaged mitochondria in spheroid structures. These spheroids were penetrated by astrocytic processes, and the mitochondria were transferred to astrocytes and degraded through mitophagy. (c) Neurons can release damaged mitochondria to be internalized by adjacent astrocytes for clearance. On the contrary, astrocytes can release functional mitochondria that enter neurons. (d) In a mouse model of PD with dementia, oxidized mtDNA could be observed being released outside the neurons. Injection of damaged mtDNA into the wild-type mouse brain triggers PD-like pathology including dopaminergic neuronal loss, pSyn accumulation and astrogliosis in the lesioned site. Damaged mtDNA also spread neurodegeneration to distant brain regions. The figure was created with BioRender.com, accessed on 28 November 2023.</p>
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<p>Mitochondrial transfer in PD. Mitochondrial treatment via intravenous administration in experimental MPTP mouse model and intranasal delivery and injection into medial forebrain bundle in 6-OHDA rat model resulted in mitochondrial function recovery, improved neuronal survival and better behavioral outcomes. The figure was created with BioRender.com, accessed on 30 November 2023.</p>
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