Most children with medulloblastoma (MB) achieve remission, but some face very aggressive metastatic tumors. Their dismal outcome highlights the critical need to advance therapeutic approaches that benefit such high-risk patients. Minnelide, a clinically relevant analog of the natural product triptolide, has oncostatic activity in both preclinical and early clinical settings. Despite its efficacy and tolerable toxicity, this compound has not been evaluated in MB. Utilizing a bioinformatic data set that integrates cellular drug response data with gene expression, we predicted that Group 3 (G3) MB, which has a poor 5-year survival, would be sensitive to triptolide/Minnelide. We subsequently showed that both triptolide and Minnelide attenuate the viability of G3 MB cells ex vivo. Transcriptomic analyses identified MYC signaling, a pathologically relevant driver of G3 MB, as a downstream target of this class of drugs. We validated this MYC dependency in G3 MB cells and showed that triptolide exerts its efficacy by reducing both MYC transcription and MYC protein stability. Importantly, Minnelide acted on MYC to reduce tumor growth and leptomeningeal spread, which resulted in improved survival of G3 MB animal models. Moreover, Minnelide improved the efficacy of adjuvant chemotherapy, further highlighting its potential for the treatment of MYC-driven G3 MB.
Jezabel Rodriguez-Blanco, April D. Salvador, Robert K. Suter, Marzena Swiderska-Syn, Isabel Palomo-Caturla, Valentin Kliebe, Pritika Shahani, Kendell Peterson, Maria Turos-Cabal, Megan E. Vieira, Daniel T. Wynn, Ashley J. Howell, Fan Yang, Yuguang Ban, Heather J. McCrea, Frederique Zindy, Etienne Danis, Rajeev Vibhakar, Anna Jermakowicz, Vanesa Martin, Christopher C. Coss, Brent T. Harris, Aguirre de Cubas, X. Steven Chen, Thibaut Barnoud, Martine F. Roussel, Nagi G. Ayad, David J. Robbins
The identification of genes that confer either extension of life span or accelerate age-related decline was a step forward in understanding the mechanisms of aging and revealed that it is partially controlled by genetics and transcriptional programs. Here, we discovered that the human DNA sequence C16ORF70 encodes a protein, named MYTHO (macroautophagy and youth optimizer), which controls life span and health span. MYTHO protein is conserved from Caenorhabditis elegans to humans and its mRNA was upregulated in aged mice and elderly people. Deletion of the orthologous myt-1 gene in C. elegans dramatically shortened life span and decreased animal survival upon exposure to oxidative stress. Mechanistically, MYTHO is required for autophagy likely because it acts as a scaffold that binds WIPI2 and BCAS3 to recruit and assemble the conjugation system at the phagophore, the nascent autophagosome. We conclude that MYTHO is a transcriptionally regulated initiator of autophagy that is central in promoting stress resistance and healthy aging.
Anais Franco-Romero, Valeria Morbidoni, Giulia Milan, Roberta Sartori, Jesper Wulff, Vanina Romanello, Andrea Armani, Leonardo Salviati, Maria Conte, Stefano Salvioli, Claudio Franceschi, Viviana Buonomo, Casey O. Swoboda, Paolo Grumati, Luca Pannone, Simone Martinelli, Harold B.J. Jefferies, Ivan Dikic, Jennifer van der Laan, Filipe Cabreiro, Douglas P. Millay, Sharon A. Tooze, Eva Trevisson, Marco Sandri
Cerebral arteriovenous malformations (AVMs) are the most common vascular malformations worldwide and the leading cause of hemorrhagic strokes that may result in crippling neurological deficits. Here, using recently generated mouse models, we uncovered that cerebral endothelial cells (ECs) acquired mesenchymal markers and caused vascular malformations. Interestingly, we found that limiting endothelial histone deacetylase 2 (HDAC2) prevented cerebral ECs from undergoing mesenchymal differentiation and reduced cerebral AVMs. We found that endothelial expression of HDAC2 and enhancer of zeste homolog 1 (EZH1) was altered in cerebral AVMs. These alterations changed the abundance of H4K8ac and H3K27me in the genes regulating endothelial and mesenchymal differentiation, which caused the ECs to acquire mesenchymal characteristics and form AVMs. This investigation demonstrated that the induction of HDAC2 altered specific histone modifications, which resulted in mesenchymal characteristics in the ECs and cerebral AVMs. The results provide insight into the epigenetic impact on AVMs.
Yan Zhao, Xiuju Wu, Yang Yang, Li Zhang, Xinjiang Cai, Sydney Chen, Abigail Vera, Jaden Ji, Kristina I. Boström, Yucheng Yao
Neutrophil hyperactivity and neutrophil extracellular trap release (NETosis) appear to play important roles in the pathogenesis of the thromboinflammatory autoimmune disease known as antiphospholipid syndrome (APS). The understanding of neutrophil metabolism has advanced tremendously in the past decade, and accumulating evidence suggests that a variety of metabolic pathways guide neutrophil activities in health and disease. Our previous work characterizing the transcriptome of APS neutrophils revealed that genes related to glycolysis, glycogenolysis, and the pentose phosphate pathway (PPP) were significantly upregulated. Here, we found that neutrophils from patients with APS used glycolysis more avidly than neutrophils from people in the healthy control group, especially when the neutrophils were from patients with APS with a history of microvascular disease. In vitro, inhibiting either glycolysis or the PPP tempered phorbol myristate acetate– and APS IgG–induced NETosis, but not NETosis triggered by a calcium ionophore. In mice, inhibiting either glycolysis or the PPP reduced neutrophil reactive oxygen species production and suppressed APS IgG–induced NETosis ex vivo. When APS-associated thrombosis was evaluated in mice, inhibiting either glycolysis or the PPP markedly suppressed thrombosis and circulating NET remnants. In summary, these data identify a potential role for restraining neutrophil glucose flux in the treatment of APS.
Ajay Tambralli, Alyssa Harbaugh, Somanathapura K. NaveenKumar, Megan D. Radyk, Christine E. Rysenga, Kaitlyn Sabb, Julia M. Hurley, Gautam J. Sule, Srilakshmi Yalavarthi, Shanea K. Estes, Claire K. Hoy, Tristin Smith, Cyrus Sarosh, Jacqueline A. Madison, Jordan K. Schaefer, Suman L. Sood, Yu Zuo, Amr H. Sawalha, Costas A. Lyssiotis, Jason S. Knight
Viral vectors are being used for the treatment of cancer. Yet, their efficacy varies among tumors and their use poses challenges in immunosuppressed patients, underscoring the need for alternatives. We report striking antitumoral effects by a nonlytic viral vector based on attenuated lymphocytic choriomeningitis virus (r3LCMV). We show in multiple tumor models that injection of tumor-bearing mice with this vector results in improved tumor control and survival. Importantly, r3LCMV improved tumor control in immunodeficient Rag1–/– mice and MyD88–/– mice, suggesting that multiple pathways contributed to the antitumoral effects. The antitumoral effects of r3LCMV were also observed when this vector was administered several weeks before tumor challenges, suggesting the induction of trained immunity. Single-cell RNA sequencing analyses, antibody blockade experiments, and knockout models revealed a critical role for host-intrinsic IFN-I in the antitumoral efficacy of r3LCMV vectors. Collectively, these data demonstrate potent antitumoral effects by r3LCMV vectors and unveil multiple mechanisms underlying their antitumoral efficacy.
Young Rock Chung, Bakare Awakoaiye, Tanushree Dangi, Nahid Irani, Slim Fourati, Pablo Penaloza-MacMaster
Proliferative glomerulonephritis is a severe condition that often leads to kidney failure. There is a significant lack of effective treatment for these disorders. Here, following the identification of a somatic PIK3CA gain-of-function mutation in podocytes of a patient, we demonstrate using multiple genetically engineered mouse models, single-cell RNA sequencing, and spatial transcriptomics the crucial role played by this pathway for proliferative glomerulonephritis development by promoting podocyte proliferation, dedifferentiation, and inflammation. Additionally, we show that alpelisib, a PI3Kα inhibitor, improves glomerular lesions and kidney function in different mouse models of proliferative glomerulonephritis and lupus nephritis by targeting podocytes. Surprisingly, we determined that pharmacological inhibition of PI3Kα affects B and T lymphocyte populations in lupus nephritis mouse models, with a decrease in the production of proinflammatory cytokines, autoantibodies, and glomerular complement deposition, which are all characteristic features of PI3Kδ inhibition, the primary PI3K isoform expressed in lymphocytes. Importantly, PI3Kα inhibition does not impact lymphocyte function under normal conditions. These findings were then confirmed in human lymphocytes isolated from patients with active lupus nephritis. In conclusion, we demonstrate the major role played by PI3Kα in proliferative glomerulonephritis and show that in this condition, alpelisib acts on both podocytes and the immune system.
Junna Yamaguchi, Pierre Isnard, Noémie Robil, Pierre de la Grange, Clément Hoguin, Alain Schmitt, Aurélie Hummel, Jérôme Megret, Nicolas Goudin, Marine Luka, Mickaël M. Ménager, Cécile Masson, Mohammed Zarhrate, Christine Bôle-Feysot, Michalina Janiszewska, Kornelia Polyak, Julien Dairou, Sara Baldassari, Stéphanie Baulac, Christine Broissand, Christophe Legendre, Fabiola Terzi, Guillaume Canaud
Leigh syndrome is the most common inherited mitochondrial disease in children and is often fatal within the first few years of life. In 2020, mutations in the gene encoding sulfide:quinone oxidoreductase (SQOR), a mitochondrial protein, were identified as a cause of Leigh syndrome. Here, we report that mice with a mutation in the gene encoding SQOR (SqorΔN/ΔN mice), which prevented SQOR from entering mitochondria, had clinical and pathological manifestations of Leigh syndrome. SqorΔN/ΔN mice had increased blood lactate levels that were associated with markedly decreased complex IV activity and increased hydrogen sulfide (H2S) levels. Because H2S is produced by both gut microbiota and host tissue, we tested whether metronidazole (a broad-spectrum antibiotic) or a sulfur-restricted diet rescues SqorΔN/ΔN mice from developing Leigh syndrome. Daily treatment with metronidazole alleviated increased H2S levels, normalized complex IV activity and blood lactate levels, and prolonged the survival of SqorΔN/ΔN mice. Similarly, a sulfur-restricted diet normalized blood lactate levels and inhibited the development of Leigh syndrome. Taken together, these observations suggest that mitochondrial SQOR is essential to prevent systemic accumulation of H2S. Metronidazole administration and a sulfur-restricted diet may be therapeutic approaches to treatment of patients with Leigh syndrome caused by mutations in SQOR.
Eiki Kanemaru, Kakeru Shimoda, Eizo Marutani, Masanobu Morita, Maria Miranda, Yusuke Miyazaki, Claire Sinow, Rohit Sharma, Fangcong Dong, Donald B. Bloch, Takaaki Akaike, Fumito Ichinose
It is unknown which posttranscriptional regulatory mechanisms are required for oncogenic competence. Here, we show that the LIN28 family of RNA-binding proteins (RBPs), which facilitate posttranscriptional RNA metabolism within ribonucleoprotein networks, is essential for the initiation of diverse oncotypes of hepatocellular carcinoma (HCC). In HCC models driven by NRASG12V/Tp53, CTNNB1/YAP/Tp53, or AKT/Tp53, mice without Lin28a and Lin28b were markedly impaired in cancer initiation. We biochemically defined an oncofetal regulon of 15 factors connected to LIN28 through direct mRNA and protein interactions. Interestingly, all were RBPs and only 1 of 15 was a Let-7 target. Polysome profiling and reporter assays showed that LIN28B directly increased the translation of 8 of these 15 RBPs. As expected, overexpression of LIN28B and IGFBP1-3 was able to genetically rescue cancer initiation. Using this platform to probe components downstream of LIN28, we found that 8 target RBPs were able to restore NRASG12V/Tp53 cancer formation in Lin28a/Lin28b-deficient mice. Furthermore, these LIN28B targets promote cancer initiation through an increase in protein synthesis. LIN28B, central to an RNP regulon that increases translation of RBPs, is important for tumor initiation in the liver.
Meng-Hsiung Hsieh, Yonglong Wei, Lin Li, Liem H. Nguyen, Yu-Hsuan Lin, Jung M. Yong, Xuxu Sun, Xun Wang, Xin Luo, Sarah K. Knutson, Christina Bracken, George Q. Daley, John T. Powers, Hao Zhu
The surface receptor CD8α is present on 20%–80% of human (but not mouse) NK cells, yet its function on NK cells remains poorly understood. CD8α expression on donor NK cells was associated with a lack of therapeutic responses in patients with leukemia in prior studies, thus, we hypothesized that CD8α may affect critical NK cell functions. Here, we discovered that CD8α– NK cells had improved control of leukemia in xenograft models compared with CD8α+ NK cells, likely due to an enhanced capacity for proliferation. Unexpectedly, we found that CD8α expression was induced on approximately 30% of previously CD8α– NK cells following IL-15 stimulation. These induced CD8α+ (iCD8α+) NK cells had the greatest proliferation, responses to IL-15 signaling, and metabolic activity compared with those that sustained existing CD8α expression (sustained CD8α+) or those that remained CD8α– (persistent CD8α–). These iCD8α+ cells originated from an IL-15Rβhi NK cell population, with CD8α expression dependent on the transcription factor RUNX3. Moreover, CD8A CRISPR/Cas9 deletion resulted in enhanced responses through the activating receptor NKp30, possibly by modulating KIR inhibitory function. Thus, CD8α status identified human NK cell capacity for IL-15–induced proliferation and metabolism in a time-dependent fashion, and its presence had a suppressive effect on NK cell–activating receptors.
Celia C. Cubitt, Pamela Wong, Hannah K. Dorando, Jennifer A. Foltz, Jennifer Tran, Lynne Marsala, Nancy D. Marin, Mark Foster, Timothy Schappe, Hijab Fatima, Michelle Becker-Hapak, Alice Y. Zhou, Kimberly Hwang, Miriam T. Jacobs, David A. Russler-Germain, Emily M. Mace, Melissa M. Berrien-Elliott, Jacqueline E. Payton, Todd A. Fehniger
Reproduction is safeguarded by multiple, often cooperative, regulatory networks. Kisspeptin signaling, via KISS1R, plays a fundamental role in reproductive control, primarily by regulation of hypothalamic GnRH neurons. We disclose herein a pathway for direct kisspeptin actions in astrocytes that contributes to central reproductive modulation. Protein-protein interaction and ontology analyses of hypothalamic proteomic profiles after kisspeptin stimulation revealed that glial/astrocyte markers are regulated by kisspeptin in mice. This glial-kisspeptin pathway was validated by the demonstrated expression of Kiss1r in mouse astrocytes in vivo and astrocyte cultures from humans, rats, and mice, where kisspeptin activated canonical intracellular signaling-pathways. Cellular coexpression of Kiss1r with the astrocyte markers GFAP and S100-β occurred in different brain regions, with higher percentage in Kiss1- and GnRH-enriched areas. Conditional ablation of Kiss1r in GFAP-positive cells in the G-KiR-KO mouse altered gene expression of key factors in PGE2 synthesis in astrocytes and perturbed astrocyte-GnRH neuronal appositions, as well as LH responses to kisspeptin and LH pulsatility, as surrogate marker of GnRH secretion. G-KiR-KO mice also displayed changes in reproductive responses to metabolic stress induced by high-fat diet, affecting female pubertal onset, estrous cyclicity, and LH-secretory profiles. Our data unveil a nonneuronal pathway for kisspeptin actions in astrocytes, which cooperates in fine-tuning the reproductive axis and its responses to metabolic stress.
Encarnacion Torres, Giuliana Pellegrino, Melissa Granados-Rodríguez, Antonio C. Fuentes-Fayos, Inmaculada Velasco, Adrian Coutteau-Robles, Amandine Legrand, Marya Shanabrough, Cecilia Perdices-Lopez, Silvia Leon, Shel H. Yeo, Stephen M. Manchishi, Maria J. Sánchez-Tapia, Victor M. Navarro, Rafael Pineda, Juan Roa, Frederick Naftolin, Jesús Argente, Raúl M. Luque, Julie A. Chowen, Tamas L. Horvath, Vincent Prevot, Ariane Sharif, William H. Colledge, Manuel Tena-Sempere, Antonio Romero-Ruiz
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