Background Monocyte chemoattractant protein (CCL2/MCP-1) is a chemokine that attracts cells invo... more Background Monocyte chemoattractant protein (CCL2/MCP-1) is a chemokine that attracts cells involved in the immune/inflammatory response. As microglia are one of the main cell types sustaining inflammation in brain, we proposed here to analyze the direct effects of MCP-1 on cultured primary microglia. Methods Primary microglia and neuronal cultures were obtained from neonatal and embryonic Wistar rats, respectively. Microglia were incubated with
CX3CL1 is a chemokine for which neurons constitute its primary source within the brain. Besides a... more CX3CL1 is a chemokine for which neurons constitute its primary source within the brain. Besides acting as a chemokine, CX3CL1 regulates multiple processes and is known to inhibit microglial activation. Because of this, CX3CL1 is considered as a messenger used by neurons to communicate with microglia. Similarly, the neurotransmitter noradrenaline reduces microglial activation and production of neurotoxic agents. Based on this, the regulation of neuronal CX3CXL1 by noradrenaline was analyzed. In primary cortical neurons, noradrenaline induced the accumulation of CX3CL1 protein and mRNA. Noradrenaline also increased CX3CL1 in its soluble form despite the inhibition of the activity and synthesis of ADAM10 and ADAM17, the main proteases known to cleave CX3CL1 from the neuronal membrane. Noradrenaline-treated neurons displayed a higher degree of dendritic arborization and a characteristic accumulation of CX3CL1 in the dendritic bifurcation zones. The soluble CX3CL1 produced by neurons aft...
The pathophysiology of psychotic disorders is multifactorial, including alterations in the immune... more The pathophysiology of psychotic disorders is multifactorial, including alterations in the immune system caused by exogenous or endogenous factors. Epidemiological and experimental studies indicate that infections during the gestational period represent a risk factor to develop schizophrenia (SZ) along lifetime. Here, we tested the hypothesis that the antipsychotic paliperidone regulates immune-related brain effects in an experimental model of SZ. A well described prenatal immune activation model of SZ in mice by maternal injection of the viral mimetic poly(I:C) during pregnancy was used. Young-adult offspring animals (60PND) received paliperidone ip (0.05 mg/kg) for 21 consecutive days. One day after last injection, animals were submitted to a cognitive test and brain frontal cortex (FC) samples were obtained for biochemical determinations. The adults showed an activated innate immune receptor TLR-3 signaling pathway, oxidative/nitrosative stress and accumulation of pro-inflammator...
Patients with major depression who are otherwise medically healthy have activated inflammatory pa... more Patients with major depression who are otherwise medically healthy have activated inflammatory pathways in their organism. It has been described that depression is not only escorted by inflammation but also by induction of multiple oxidative/nitrosative stress pathways. Nevertheless, there are finely regulated mechanisms involved in preserving cells from damage, such as the antioxidant nuclear transcription factor Nrf2. We aim to explore in a depression-like model the Nrf2 pathway in the prefrontal cortex (PFC) and the hippocampus of rats and to analyze whether antidepressants affect the antioxidant activity of the Nrf2 pathway. Male Wistar rats were exposed to chronic mild stress (CMS) and some of them were treated with desipramine, escitalopram or duloxetine. We studied the expression of upstream and downstream elements of the Nrf2 pathway and the oxidative damage induced by the CMS. After CMS, there is an inhibition of upstream and downstream elements of the Nrf2 pathway in the P...
Advances in Experimental Medicine and Biology, 2014
Among all the chemokines known so far, chemokine (C-C motif) ligand 2 (CCL2) is probably the best... more Among all the chemokines known so far, chemokine (C-C motif) ligand 2 (CCL2) is probably the best characterized. This is mainly due to the therapeutic potential attributed to its regulation. The suppression of CCL2 function may reduce the attraction of immune cells to the sites of inflammation and therefore slow down the progression of inflammation and the tissue damage that may be associated to it. While this has proven to be right in diverse conditions, it has also been described to have deleterious consequences such as a dual effect that is also frequently observed in other endogenous defense systems. This review discusses current knowledge about CCL2 involvement in different neurodegenerative diseases as well as its anti-inflammatory and neuro-protective actions.
A number of findings suggest that inflammation plays a role in the pathophysiology of schizophren... more A number of findings suggest that inflammation plays a role in the pathophysiology of schizophrenia. Taking into account a physiological balance between pro- and anti-inflammatory mediators, we measured the plasma levels of cyclooxygenase-derived mediators and other key pro- and anti-inflammatory transcription factors in peripheral blood mononuclear cells (PBMC). Forty healthy subjects and 46 treated chronic schizophrenic patients with an acutely exacerbated condition who met DSM-IV criteria were included. COX by-products prostaglandin E2 (PGE2) and 15d-prostaglandin J2 (15d-PGJ2) plasma levels were measured by EIA. Peroxisome proliferator-activated receptor gamma (PPARγ) as well as nuclear factor kappaB (NFκB) activity in nuclear extracts from PBMC and expression of its inhibitory subunit IκBα in cytosolic extracts were determined using ELISA-based kits. Schizophrenic patients showed higher plasma levels of pro-inflammatory PGE2 than age-matched controls (p=0.043). On the contrary, levels of anti-inflammatory 15-d-PGJ2 were lower (p=0.004), correlating with a lower expression of its nuclear target, PPARγ in nuclear extracts from PBMC (p=0.001). Although no changes in NFκB activity were observed between patients and healthy controls, the expression of its inhibitory protein IκBα was lower in the patients compared to the controls (p=0.027). These findings suggest that schizophrenia is associated with a systemic imbalance in the plasma levels of pro-inflammatory/anti-inflammatory prostaglandins in favor of the former. Furthermore, the expression and activity of anti-inflammatory PPARγ are diminished in PBMC, which indicates a state of inflammation and blunted anti-inflammatory counterbalancing mechanisms at systemic level in these patients.
Background The innate immune response is the first line of defence against invading microorganism... more Background The innate immune response is the first line of defence against invading microorganisms and it is also activated in different neurologic/neurodegenerative pathological scenarios. As a result, the family of the innate immune toll-like receptors (TLRs) and, in particular, the genetic/pharmacological manipulation of the TLR-4 signalling pathway emerges as a potential therapeutic strategy. Growing evidence relates stress exposure with altered immune responses, but the precise role of TLR-4 remains partly unknown. Methods The present study aimed to elucidate whether the elements of the TLR-4 signalling pathway are activated after acute stress exposure in rat brain frontal cortex and its role in the regulation of the stress-induced neuroinflammatory response, by means of its pharmacological modulation with the intravenous administration of the TLR-4 specific inhibitor TAK-242. Considering that TLR-4 responds predominantly to lipopolysaccharide from gram-negative bacteria, we ch...
Stress exposure elicits neuroinflammation and oxidative damage in brain, and stress-related neuro... more Stress exposure elicits neuroinflammation and oxidative damage in brain, and stress-related neurological and neuropsychiatric diseases have been associated with cell damage and death. Mangiferin (MAG) is a polyphenolic compound abundant in the stem bark of Mangifera indica L. with antioxidant and anti-inflammatory properties in different experimental settings. In this study, the capacity of MAG to prevent neuroinflammation and brain oxidative damage induced by stress exposure was investigated. Young-adult male Wistar rats immobilized during 6 h were administered by oral gavage with increasing doses of MAG (15, 30, and 60 mg/Kg), respectively, 7 days before stress. Prior treatment with MAG prevented all of the following stress-induced effects: (1) increase in glucocorticoids (GCs) and interleukin-1β (IL-1β) plasma levels, (2) loss of redox balance and reduction in catalase brain levels, (3) increase in pro-inflammatory mediators, such as tumor necrosis factor alpha TNF-α and its receptor TNF-R1, nuclear factor-kappa B (NF-κB) and synthesis enzymes, such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), (4) increase in lipid peroxidation. These multifaceted protective effects suggest that MAG administration could be a new therapeutic strategy in neurological/neuropsychiatric pathologies in which hypothalamic/pituitary/adrenal (HPA) stress axis dysregulation, neuroinflammation, and oxidative damage take place in their pathophysiology.
Having previously observed that noradrenaline activation of β adrenergic receptors induces the sy... more Having previously observed that noradrenaline activation of β adrenergic receptors induces the synthesis of the chemokine monocyte chemoattractant protein (CCL2/MCP-1) in astrocytes, it is our interest to analyze the mechanisms involved in this process, particularly the possible effect of noradrenaline-modulating drugs. The treatment of primary rat astrocyte cultures with the noradrenaline transporter inhibitors desipramine or atomoxetine induced the expression and synthesis of CCL2/MCP-1 in these cells. This effect of both drugs in vitro suggests that CCL2/MCP-1 expression could also be modulated by some mechanism independent of the elevation of brain noradrenaline levels. This was confirmed by measuring a reduction in CCL2/MCP-1 production by the treatment with the α2 adrenergic receptor agonist clonidine. Accordingly, the blockade of α2 adrenergic receptors with yohimbine potentiated the production of MCP-1 stimulated by the activation of β receptors. While the activation of β adrenergic receptors and the subsequent elevation of cAMP levels seem to be the main pathway for noradrenaline to induce CCL2/MCP-1 in astrocytes, our data indicate that the α2 adrenergic receptors also regulate CCL2/MCP-1 expression working as inhibitory mediators.
The decline in brain noradrenaline levels is associated with the progression of certain neurodege... more The decline in brain noradrenaline levels is associated with the progression of certain neurodegenerative diseases. This seems to be due, at least in part, to the ability of noradrenaline to limit glial activation and to reduce the damage associated with it. Our previous studies of the mechanisms involved in this process indicate that noradrenaline induces the production of the chemokine CCL2 in astrocytes. While CCL2 can protect neurons against certain injuries, its overproduction has also proven to be harmful and to prevent noradrenaline neuroprotective effects. Therefore, in this study, we analyze if the modifications caused to astrocytes by an excessive production of CCL2 may alter their response to noradrenaline. Using primary cultures of rat cortical astrocytes, we observed that CCL2 enhances the production of beta 2 adrenergic receptors in these cells. While this potentiates noradrenaline signaling through cAMP, the activation of the transcription factor CREB is inhibited by ...
It has been known for many years that the endogenous neurotransmitter noradrenaline (NA) exerts a... more It has been known for many years that the endogenous neurotransmitter noradrenaline (NA) exerts anti-inflammatory and neuroprotective effects both in vitro and in vivo. In many cases the site of action of NA are beta-adrenergic receptors (βARs), causing an increase in intracellular levels of cAMP which initiates a broad cascade of events including suppression of inflammatory transcription factor activities, alterations in nuclear localization of proteins, and induction of patterns of gene expression mediated through activity of the CREB transcription factor. These changes lead not only to reduced inflammatory events, but also contribute to neuroprotective actions of NA by increasing expression of neurotrophic substances including BDNF, GDNF, and NGF. These properties have prompted studies to determine if treatments with drugs to raise CNS NA levels could provide benefit in various neurological conditions and diseases having an inflammatory component. Moreover, increasing evidence shows that disruptions in endogenous NA levels occurs in several diseases and conditions including Alzheimer's disease (AD), Parkinson's disease (PD), Down's syndrome, posttraumatic stress disorder (PTSD), and multiple sclerosis (MS), suggesting that damage to NA producing neurons is a common factor that contributes to the initiation or progression of neuropathology. Methods to increase NA levels, or to reduce damage to noradrenergic neurons, therefore represent potential preventative as well as therapeutic approaches to disease.
Background Monocyte chemoattractant protein (CCL2/MCP-1) is a chemokine that attracts cells invo... more Background Monocyte chemoattractant protein (CCL2/MCP-1) is a chemokine that attracts cells involved in the immune/inflammatory response. As microglia are one of the main cell types sustaining inflammation in brain, we proposed here to analyze the direct effects of MCP-1 on cultured primary microglia. Methods Primary microglia and neuronal cultures were obtained from neonatal and embryonic Wistar rats, respectively. Microglia were incubated with
CX3CL1 is a chemokine for which neurons constitute its primary source within the brain. Besides a... more CX3CL1 is a chemokine for which neurons constitute its primary source within the brain. Besides acting as a chemokine, CX3CL1 regulates multiple processes and is known to inhibit microglial activation. Because of this, CX3CL1 is considered as a messenger used by neurons to communicate with microglia. Similarly, the neurotransmitter noradrenaline reduces microglial activation and production of neurotoxic agents. Based on this, the regulation of neuronal CX3CXL1 by noradrenaline was analyzed. In primary cortical neurons, noradrenaline induced the accumulation of CX3CL1 protein and mRNA. Noradrenaline also increased CX3CL1 in its soluble form despite the inhibition of the activity and synthesis of ADAM10 and ADAM17, the main proteases known to cleave CX3CL1 from the neuronal membrane. Noradrenaline-treated neurons displayed a higher degree of dendritic arborization and a characteristic accumulation of CX3CL1 in the dendritic bifurcation zones. The soluble CX3CL1 produced by neurons aft...
The pathophysiology of psychotic disorders is multifactorial, including alterations in the immune... more The pathophysiology of psychotic disorders is multifactorial, including alterations in the immune system caused by exogenous or endogenous factors. Epidemiological and experimental studies indicate that infections during the gestational period represent a risk factor to develop schizophrenia (SZ) along lifetime. Here, we tested the hypothesis that the antipsychotic paliperidone regulates immune-related brain effects in an experimental model of SZ. A well described prenatal immune activation model of SZ in mice by maternal injection of the viral mimetic poly(I:C) during pregnancy was used. Young-adult offspring animals (60PND) received paliperidone ip (0.05 mg/kg) for 21 consecutive days. One day after last injection, animals were submitted to a cognitive test and brain frontal cortex (FC) samples were obtained for biochemical determinations. The adults showed an activated innate immune receptor TLR-3 signaling pathway, oxidative/nitrosative stress and accumulation of pro-inflammator...
Patients with major depression who are otherwise medically healthy have activated inflammatory pa... more Patients with major depression who are otherwise medically healthy have activated inflammatory pathways in their organism. It has been described that depression is not only escorted by inflammation but also by induction of multiple oxidative/nitrosative stress pathways. Nevertheless, there are finely regulated mechanisms involved in preserving cells from damage, such as the antioxidant nuclear transcription factor Nrf2. We aim to explore in a depression-like model the Nrf2 pathway in the prefrontal cortex (PFC) and the hippocampus of rats and to analyze whether antidepressants affect the antioxidant activity of the Nrf2 pathway. Male Wistar rats were exposed to chronic mild stress (CMS) and some of them were treated with desipramine, escitalopram or duloxetine. We studied the expression of upstream and downstream elements of the Nrf2 pathway and the oxidative damage induced by the CMS. After CMS, there is an inhibition of upstream and downstream elements of the Nrf2 pathway in the P...
Advances in Experimental Medicine and Biology, 2014
Among all the chemokines known so far, chemokine (C-C motif) ligand 2 (CCL2) is probably the best... more Among all the chemokines known so far, chemokine (C-C motif) ligand 2 (CCL2) is probably the best characterized. This is mainly due to the therapeutic potential attributed to its regulation. The suppression of CCL2 function may reduce the attraction of immune cells to the sites of inflammation and therefore slow down the progression of inflammation and the tissue damage that may be associated to it. While this has proven to be right in diverse conditions, it has also been described to have deleterious consequences such as a dual effect that is also frequently observed in other endogenous defense systems. This review discusses current knowledge about CCL2 involvement in different neurodegenerative diseases as well as its anti-inflammatory and neuro-protective actions.
A number of findings suggest that inflammation plays a role in the pathophysiology of schizophren... more A number of findings suggest that inflammation plays a role in the pathophysiology of schizophrenia. Taking into account a physiological balance between pro- and anti-inflammatory mediators, we measured the plasma levels of cyclooxygenase-derived mediators and other key pro- and anti-inflammatory transcription factors in peripheral blood mononuclear cells (PBMC). Forty healthy subjects and 46 treated chronic schizophrenic patients with an acutely exacerbated condition who met DSM-IV criteria were included. COX by-products prostaglandin E2 (PGE2) and 15d-prostaglandin J2 (15d-PGJ2) plasma levels were measured by EIA. Peroxisome proliferator-activated receptor gamma (PPARγ) as well as nuclear factor kappaB (NFκB) activity in nuclear extracts from PBMC and expression of its inhibitory subunit IκBα in cytosolic extracts were determined using ELISA-based kits. Schizophrenic patients showed higher plasma levels of pro-inflammatory PGE2 than age-matched controls (p=0.043). On the contrary, levels of anti-inflammatory 15-d-PGJ2 were lower (p=0.004), correlating with a lower expression of its nuclear target, PPARγ in nuclear extracts from PBMC (p=0.001). Although no changes in NFκB activity were observed between patients and healthy controls, the expression of its inhibitory protein IκBα was lower in the patients compared to the controls (p=0.027). These findings suggest that schizophrenia is associated with a systemic imbalance in the plasma levels of pro-inflammatory/anti-inflammatory prostaglandins in favor of the former. Furthermore, the expression and activity of anti-inflammatory PPARγ are diminished in PBMC, which indicates a state of inflammation and blunted anti-inflammatory counterbalancing mechanisms at systemic level in these patients.
Background The innate immune response is the first line of defence against invading microorganism... more Background The innate immune response is the first line of defence against invading microorganisms and it is also activated in different neurologic/neurodegenerative pathological scenarios. As a result, the family of the innate immune toll-like receptors (TLRs) and, in particular, the genetic/pharmacological manipulation of the TLR-4 signalling pathway emerges as a potential therapeutic strategy. Growing evidence relates stress exposure with altered immune responses, but the precise role of TLR-4 remains partly unknown. Methods The present study aimed to elucidate whether the elements of the TLR-4 signalling pathway are activated after acute stress exposure in rat brain frontal cortex and its role in the regulation of the stress-induced neuroinflammatory response, by means of its pharmacological modulation with the intravenous administration of the TLR-4 specific inhibitor TAK-242. Considering that TLR-4 responds predominantly to lipopolysaccharide from gram-negative bacteria, we ch...
Stress exposure elicits neuroinflammation and oxidative damage in brain, and stress-related neuro... more Stress exposure elicits neuroinflammation and oxidative damage in brain, and stress-related neurological and neuropsychiatric diseases have been associated with cell damage and death. Mangiferin (MAG) is a polyphenolic compound abundant in the stem bark of Mangifera indica L. with antioxidant and anti-inflammatory properties in different experimental settings. In this study, the capacity of MAG to prevent neuroinflammation and brain oxidative damage induced by stress exposure was investigated. Young-adult male Wistar rats immobilized during 6 h were administered by oral gavage with increasing doses of MAG (15, 30, and 60 mg/Kg), respectively, 7 days before stress. Prior treatment with MAG prevented all of the following stress-induced effects: (1) increase in glucocorticoids (GCs) and interleukin-1β (IL-1β) plasma levels, (2) loss of redox balance and reduction in catalase brain levels, (3) increase in pro-inflammatory mediators, such as tumor necrosis factor alpha TNF-α and its receptor TNF-R1, nuclear factor-kappa B (NF-κB) and synthesis enzymes, such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), (4) increase in lipid peroxidation. These multifaceted protective effects suggest that MAG administration could be a new therapeutic strategy in neurological/neuropsychiatric pathologies in which hypothalamic/pituitary/adrenal (HPA) stress axis dysregulation, neuroinflammation, and oxidative damage take place in their pathophysiology.
Having previously observed that noradrenaline activation of β adrenergic receptors induces the sy... more Having previously observed that noradrenaline activation of β adrenergic receptors induces the synthesis of the chemokine monocyte chemoattractant protein (CCL2/MCP-1) in astrocytes, it is our interest to analyze the mechanisms involved in this process, particularly the possible effect of noradrenaline-modulating drugs. The treatment of primary rat astrocyte cultures with the noradrenaline transporter inhibitors desipramine or atomoxetine induced the expression and synthesis of CCL2/MCP-1 in these cells. This effect of both drugs in vitro suggests that CCL2/MCP-1 expression could also be modulated by some mechanism independent of the elevation of brain noradrenaline levels. This was confirmed by measuring a reduction in CCL2/MCP-1 production by the treatment with the α2 adrenergic receptor agonist clonidine. Accordingly, the blockade of α2 adrenergic receptors with yohimbine potentiated the production of MCP-1 stimulated by the activation of β receptors. While the activation of β adrenergic receptors and the subsequent elevation of cAMP levels seem to be the main pathway for noradrenaline to induce CCL2/MCP-1 in astrocytes, our data indicate that the α2 adrenergic receptors also regulate CCL2/MCP-1 expression working as inhibitory mediators.
The decline in brain noradrenaline levels is associated with the progression of certain neurodege... more The decline in brain noradrenaline levels is associated with the progression of certain neurodegenerative diseases. This seems to be due, at least in part, to the ability of noradrenaline to limit glial activation and to reduce the damage associated with it. Our previous studies of the mechanisms involved in this process indicate that noradrenaline induces the production of the chemokine CCL2 in astrocytes. While CCL2 can protect neurons against certain injuries, its overproduction has also proven to be harmful and to prevent noradrenaline neuroprotective effects. Therefore, in this study, we analyze if the modifications caused to astrocytes by an excessive production of CCL2 may alter their response to noradrenaline. Using primary cultures of rat cortical astrocytes, we observed that CCL2 enhances the production of beta 2 adrenergic receptors in these cells. While this potentiates noradrenaline signaling through cAMP, the activation of the transcription factor CREB is inhibited by ...
It has been known for many years that the endogenous neurotransmitter noradrenaline (NA) exerts a... more It has been known for many years that the endogenous neurotransmitter noradrenaline (NA) exerts anti-inflammatory and neuroprotective effects both in vitro and in vivo. In many cases the site of action of NA are beta-adrenergic receptors (βARs), causing an increase in intracellular levels of cAMP which initiates a broad cascade of events including suppression of inflammatory transcription factor activities, alterations in nuclear localization of proteins, and induction of patterns of gene expression mediated through activity of the CREB transcription factor. These changes lead not only to reduced inflammatory events, but also contribute to neuroprotective actions of NA by increasing expression of neurotrophic substances including BDNF, GDNF, and NGF. These properties have prompted studies to determine if treatments with drugs to raise CNS NA levels could provide benefit in various neurological conditions and diseases having an inflammatory component. Moreover, increasing evidence shows that disruptions in endogenous NA levels occurs in several diseases and conditions including Alzheimer's disease (AD), Parkinson's disease (PD), Down's syndrome, posttraumatic stress disorder (PTSD), and multiple sclerosis (MS), suggesting that damage to NA producing neurons is a common factor that contributes to the initiation or progression of neuropathology. Methods to increase NA levels, or to reduce damage to noradrenergic neurons, therefore represent potential preventative as well as therapeutic approaches to disease.
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Papers by José Madrigal