Apoptotic Neuronal Cell Death Research Articles

An increase in ER stress and unfolded protein response in iPSCs-derived neuronal cells from neuronopathic Gaucher disease patients

Gaucher disease (GD) is a lysosomal storage disorder caused by a mutation in the GBA1 gene, responsible for encoding the enzyme Glucocerebrosidase (GCase). Although neuronal death and neuroinflammation have been observed in the brains of individuals with neuronopathic Gaucher disease (nGD), the exact mechanism underlying neurodegeneration in nGD remains unclear. In this study, we used two induced pluripotent stem cells (iPSCs)-derived neuronal cell lines acquired from two type-3 GD patients (GD3-1 and GD3-2) to investigate the mechanisms underlying nGD by biochemical analyses. These iPSCs-derived neuronal cells from GD3-1 and GD3-2 exhibit an impairment in endoplasmic reticulum (ER) calcium homeostasis and an increase in unfolded protein response markers (BiP and CHOP), indicating the presence of ER stress in nGD. A significant increase in the BAX/BCL-2 ratio and an increase in Annexin V-positive cells demonstrate a notable increase in apoptotic cell death in GD iPSCs-derived neurons, suggesting downstream signaling after an increase in the unfolded protein response. Our study involves the establishment of iPSCs-derived neuronal models for GD and proposes a possible mechanism underlying nGD. This mechanism involves the activation of ER stress and the unfolded protein response, ultimately leading to apoptotic cell death in neurons.

Dynamics of Apoptotic and Necrotic Cell Death in Neurons and Glial Cells Sensorimotor Area Following Severe Traumatic Brain Injury (P3-14.018)

Dynamics of Apoptotic and Necrotic Cell Death in Neurons and Glial Cells Sensorimotor Area Following Severe Traumatic Brain Injury (P3-14.018)

Katepsin B İnhibitörü olan CA074'ün Serebral İskemi Modelinde Apoptoz ve Hücre Ölümü Üzerine Etkisi

Lysosomes and cathepsins, the most common hydrolytic enzymes in lysosomes, are available in the different models of cell death as necrosis and apoptosis. This study investigated the effect of cathepsin B-selective inhibitor CA-074 on apoptotic and necrotic neuronal cell death. Focal cerebral ischemia which has been formed by occlusion of the three-vessel consisting permanent middle cerebral artery occlusion and temporary bilateral common carotid artery occlusion for 60 minutes was selected as ischemia model. Two sets of rats were used in this study. The rats in the first set were used formeasurement of sulfhydryl groups in the lysosomal membrane, lysosomal integrity, cathepsins B and L activities and caspase-3 activity. The rats in the second set were used as histological study including "hematoxylin and eosin" for the detection of necrotic neuronal deathand "TUNEL" staining for the detection of apoptotic neuronal death. 4 mg/kg CA-074 was administered intravenouslyin the treatment group. CA-074 has substantially reduced levels of cathepsins B and L compared to ischemia and solvent groups (respectively, p<0.05 and p<0.01). Similarly, CA-074 has reduced increase in caspase-3 activity compared to ischemia and solvent groups (p<0.05). While the number of eosinophilic (necrotic) and apoptotic neurons has highly increased in post-ischemic cerebral tissue in middle cerebral artery feeding area (p<0.001), CA-074 could only reduce significantly the number of apoptotic neurons (p<0.05). CA-074 has reduced apoptotic neuronal death by inhibiting caspase and cathepsin activity. It may be useful that CA074 is used with other therapeutic drugs in stroke patients.

Molecular mechanisms underlying cyclophosphamide-induced cognitive impairment and strategies for neuroprotection in preclinical models.

Cyclophosphamide has drastically enhanced the expectancy and quality of life of cancer patients. However, it is accompanied by diverse neurological complications which are considered a dose-limiting adverse effect. Neurotoxicity caused by cyclophosphamide can manifest in numerous manners including anxiety, depression, motor dysfunction and cognitive deficits. This review article offers an overview on cyclophosphamide-induced neurotoxicity, providing a unified point of view on the possible underlying molecular mechanisms including oxidative brain damage, neuroinflammation, apoptotic neuronal cell death as well as disruption of the balance of brain neurotransmitters and neurotrophic factors. Besides, this review sheds light on the promising protective agents that have been investigated using preclinical animal models as well as their biological targets and protection mechanisms. Despite promising results in experimental models, none of these agents has been studied in clinical trials. Thus, there is lack of evidence to advocate the use of any neuroprotective agent in the clinical setting. Furthermore, none of the protective agents has been evaluated for its effect on the anticancer activity of cyclophosphamide in tumor-bearing animals. Therefore, there is a great necessity for adequate well-designed clinical studies for evaluation of the therapeutic values of these candidates. Conclusively, this review summarizes the molecular mechanisms accounting for cyclophosphamide-induced neurotoxicity together with the potential protective strategies seeking for downgrading this neurological complication, thus enhancing the quality of life and well-being of cancer patients treated with cyclophosphamide.

Eugenol alleviates neuronal damage via inhibiting inflammatory process against pilocarpine-induced status epilepticus.

Neuroinflammation is one of the most common pathological outcomes in various neurological diseases. A growing body of evidence suggests that neuroinflammation plays a pivotal role in the pathogenesis of epileptic seizures. Eugenol is the major phytoconstituent of essential oils extracted from several plants and possesses protective and anticonvulsant properties. However, it remains unclear whether eugenol exerts an anti-inflammatory effect to protect against severe neuronal damage induced by epileptic seizures. In this study, we investigated the anti-inflammatory action of eugenol in an experimental epilepsy model of pilocarpine-induced status epilepticus (SE). To examine the protective effect of eugenol via anti-inflammatory mechanisms, eugenol (200 mg/kg) was administrated daily for three days after pilocarpine-induced SE onset. The anti-inflammatory action of eugenol was evaluated by examining the expression of reactive gliosis, pro-inflammatory cytokines, nuclear factor-κB (NF-κB), and the nucleotide-binding domain leucine-rich repeat with a pyrin-domain containing 3 (NLRP3) inflammasome. Our results showed that eugenol reduced SE-induced apoptotic neuronal cell death, mitigated the activation of astrocytes and microglia, and attenuated the expression of interleukin-1β and tumor necrosis factor α in the hippocampus after SE onset. Furthermore, eugenol inhibited NF-κB activation and the formation of the NLRP3 inflammasome in the hippocampus after SE. These results suggest that eugenol is a potential phytoconstituent that suppresses the neuroinflammatory processes induced by epileptic seizures. Therefore, these findings provide evidence that eugenol has therapeutic potential for epileptic seizures.

Synthesis and neuroprotective effects of H2S-donor-peptide hybrids on hippocampal neuronal cells.

Hydrogen sulfide (H2S) has emerged as an endogenous signaling molecule that functions in many physiological and pathological processes of human cells in health and disease, including neuromodulation and neuroprotection, inflammation, angiogenesis, and vasorelaxation. The limited clinical applications of current H2S donors have led to the development of H2S donor hybrid compounds that combine current H2S donors with bioactive molecules. Finely tuned multi-targeting hybrid molecules have been shown to have complementary neuroprotective effects against reactive oxygen species (ROS)-induced oxidative stress. In this study, we developed hybrid molecules combining a dithiolethione-based slow-releasing H2S donor that exerts neuroprotective effects, with the tripeptides glycyl-L-histidyl-l-lysine (GHK) and L-alanyl-L-cystinyl-l-glutamine (ACQ), two natural products that exhibit powerful antioxidant effects. In particular, a hybrid combination of a dithiolethione-based slow-releasing H2S donor and ACQ exhibited significant neuroprotective effects against glutamate-induced oxidative damage in HT22 hippocampal neuronal cells. This hybrid remarkably suppressed Ca2+ accumulation and ROS production. Furthermore, it efficiently inhibited apoptotic neuronal cell death by blocking apoptosis-inducing factor release and its translocation to the nucleus. These results indicate that the hybrid efficiently inhibited apoptotic neuronal cell damage by complementary neuroprotective actions.

Sericin improves memory and sociability impairments evoked by transient global cerebral ischemia through suppression of hippocampal oxidative stress, inflammation, and apoptosis.

Sericin (Ser) is a natural neuroactive macromolecule with diverse pharmacological properties, and our previous findings have shown its neuroprotective potentials. This study aimed to investigate the therapeutic potential of Ser on cognitive dysfunction induced by transient global cerebral ischemia/reperfusion (tGI/R) and its mechanism of action. The tGI/R was induced in BALB/c mice by bilateral occlusion of the common carotid arteries for two 5 min followed by a 10-min reperfusion period. After 24 h, mice were treated with normal saline or different doses of Ser (100, 200, and 300 mg/kg) for 10 days. Cognitive performances were assessed using the Barnes maze and social interaction tasks. Oxidative stress markers including superoxide dismutase (SOD), glutathione peroxidase (GPx), total antioxidant capacity (TAC), and malondialdehyde (MDA) as well as pro-inflammatory cytokines (interleukin (IL)-6 and tumor necrosis factor-alpha) and anti-inflammatory cytokine (IL-10) were assessed in the hippocampus. Markers of apoptosis (pro- and cleaved caspase-9 and 3, Bax, and Bcl-2) were assessed by Western blotting. Besides, transferase-mediated dUTP nick end-labeling assay was used to detect apoptotic cell death. We show here that Ser administration improved tGI/R-induced cognitive deficits, enhanced the activity of SOD and GPx, increased TAC levels, while reduced MDA levels. Notably, Ser decreased neuronal apoptotic cell death in the hippocampal dentate gyrus (DG) region, accompanied by suppression of neuroinflammation, downregulation of pro-apoptotic proteins (caspase-9, caspases-3, and Bax), and upregulation of anti-apoptotic protein, Bcl-2. Taken together, Ser administration protected hippocampal neurons from apoptotic cell death by impeding oxidative stress and inflammatory responses and, in turn, improved cognitive function in the tGI/R mice.

Increase in membrane surface expression and phosphorylation of TRPC3 related to olfactory dysfunction in α-synuclein transgenic mice.

Olfactory impairment is an initial non‐motor symptom of Parkinson's disease that causes the deposition of aggregated α‐synuclein (α‐syn) in olfactory neurons. Transient receptor potential canonical (TRPC) channels are a diverse group of non‐selective Ca2+ entry channels involved in the progression or pathogenesis of PD via Ca2+ homeostatic regulation. However, the relationship between TRPC and α‐syn pathology in an olfactory system remains unclear. To address this issue, we assessed the olfactory function in α‐syn transgenic mice. In contrast with control mice, the transgenic mice exhibited impaired olfaction, TRPC3 activation and apoptotic neuronal cell death in the olfactory system. Similar results were observed in primary cultures of olfactory neurons, that is TRPC3 activation, increasing intracellular Ca2+ concentration and apoptotic cell death in the α‐syn‐overexpressed neurons. These changes were significantly attenuated by TRPC3 knockdown. Therefore, our findings suggest that TRPC3 activation and calcium dyshomeostasis play a key role in α‐syn‐induced olfactory dysfunction in mice.

Cortical thickness and hippocampal volume in adolescent children with obstructive sleep apnea.

Intermittent hypoxia and sleep fragmentation due to obstructive sleep apnea (OSA) may contribute to oxidative tissue damage and apoptotic neuronal cell death, inflammation, and intracellular edema in the brain. We examined whether OSA in overweight and obese adolescent children is associated with cortical thickness and hippocampal structure compared to overweight and obese controls and whether OSA severity is associated with measures of brain integrity. We calculated cortical thickness and hippocampal subfield volumes from T1-weighted images of 45 controls (age 15.43 ± 1.73 years, 21 male) and 53 adolescent children with OSA (age 15.26 ± 1.63 years, 32 male) to investigate the association of childhood OSA with the alteration of cortical structure and hippocampal subfield structural changes. In addition, we investigated the correlation between OSA severity and cortical thickness or hippocampal subfield volume using Pearson's correlation analysis. We found cortical thinning in the right superior parietal area of adolescent children with OSA (cluster size 32.29 mm2, cluster-wise corrected p-value = .030) that was negatively correlated with apnea-hypopnea index (AHI) (R=-0.27, p-value = .009) and arousal index (R=-0.25, p-value = .014). In addition, the volume of the right subiculum-head area of the hippocampus of adolescent children with OSA was larger than controls (0.19 ± 0.02 ml vs. 0.18 ± 0.02 ml, β = 13.79, false discovery rate corrected p-value = .044), and it was positively correlated with AHI (R = 0.23, p-value = .026) and arousal index (R = 0.31, p-value = .002). Our findings provide evidence for OSA-associated brain structure alterations in adolescent children prior to the onset of treatment that likely have important implications for timely intervention and continued monitoring of health outcomes.

Sodium para-aminosalicylic acid ameliorates lead-induced hippocampal neuronal apoptosis by suppressing the activation of the IP3R-Ca2+-ASK1-p38 signaling pathway

Lead (Pb) is a naturally occurring heavy metal, which can damage the brain and affect learning and memory. Sodium para-aminosalicylic acid (PAS-Na), a non-steroidal anti-inflammatory drug, can readily cross the blood-brain barrier. Our previous studies have found that PAS-Na alleviated Pb-induced hippocampal ultrastructural damage and neurodegeneration, but the mechanism has yet to be defined. Here, we investigated the molecular mechanisms that mediate Pb-induced apoptosis in hippocampal neurons, and the efficacy of PAS-Na in alleviating its effects. This work showed that juvenile developmental Pb exposure impaired rats cognitive ability by inducing apoptotic cell death in hippocampal neurons. Pb-induced neuronal apoptosis was accompanied by increased inositol 1,4,5-trisphosphate receptor (IP3R) expression and enhanced intracellular calcium [Ca2+]i levels, which resulted in increased phosphorylation of neuronal apoptosis signal-regulating kinase 1 (ASK1) and p38. Activation of ASK1 and p38 was blocked by IP3R inhibitor and a Ca2+ chelator. Importantly, PAS-Na treatment improved the Pb-induced effects on cognitive deficits in rats, concomitant with rescued neuronal apoptosis. In addition, PAS-Na reduced the expression of IP3R and the ensuing increase in intracellular Ca2+ and decreased the phosphorylation of ASK1 and p38 in Pb-exposed neurons. Taken together, this study demonstrates that the IP3R-Ca2+-ASK1-p38 signaling pathway mediates Pb-induced apoptosis in hippocampal neurons, and that PAS-Na, at a specific dose-range, ameliorates these changes. Collectively, this study sheds novel light on the cellular mechanisms that mediate PAS-Na efficacy, laying the groundwork for future research to examine the treatment potential of PAS-Na upon Pb poisoning.

Phenolic composition and neuroprotective effects of the ethyl-acetate fraction from Inonotus sanghuang against H2O2-induced apoptotic cell death of primary cortical neuronal cells.

The online version contains supplementary material available at 10.1007/s10068-022-01107-x.

NADPH oxidase-induced activation of transforming growth factor-beta-1 causes neuropathy by suppressing antioxidant signaling pathways in alcohol use disorder

Oxidative signaling and inflammatory cascades are the central mechanism in alcohol-induced brain injury, which result in glial activation, neuronal and myelin loss, neuronal apoptosis, and ultimately long-term neurological deficits. While transforming growth factor-beta1 (TGF-β1) has a significant role in inflammation and apoptosis in myriads of other pathophysiological conditions, the precise function of increased TGF-β1 in alcohol use disorder (AUD)-induced brain damage is unknown. In this study, our objective is to study ethanol-induced activation of TGF-β1 and associated mechanisms of neuroinflammation and apoptosis. Using a mouse model feeding with ethanol diet and an in vitro model in mouse cortical neuronal cultures, we explored the significance of TGF-β1 activation in the pathophysiology of AUD. Our study demonstrated that the activation of TGF-β1 in ethanol ingestion correlated with the induction of free radical generating enzyme NADPH oxidase (NOX). Further, using TGF-β type I receptor (TGF-βRI) inhibitor SB431542 and TGF-β antagonist Smad7, we established that the alcohol-induced activation of TGF-β1 impairs antioxidant signaling pathways and leads to neuroinflammation and apoptosis. Blocking of TGF-βRI or inhibition of TGF-β1 diminished TGF-β1-induced inflammation and apoptosis. Further, TGF-β1 activation increased the phosphorylation of R-Smads including Smad2 and Smad3 proteins. Using various biochemical analyses and genetic approaches, we demonstrated the up-regulation of pro-inflammatory cytokines IL-1β and TNF-α and apoptotic cell death in neurons. In conclusion, this study significantly extends our understanding of the pathophysiology of AUD and provides a unique insight for developing various therapeutic interventions by activating antioxidant signaling pathways for the treatment of AUD-induced neurological complications.

Reactive microglia and mitochondrial unfolded protein response following ventriculomegaly and behavior defects in kaolin-induced hydrocephalus

Ventriculomegaly induced by the abnormal accumulation of cerebrospinal fluid (CSF) leads to hydrocephalus, which is accompanied by neuroinflammation and mitochondrial oxidative stress. The mitochondrial stress activates mitochondrial unfolded protein response (UPRmt), which is essential for mitochondrial protein homeostasis. However, the association of inflammatory response and UPRmt in the pathogenesis of hydrocephalus is still unclear. To assess their relevance in the pathogenesis of hydrocephalus, we established a kaolin-induced hydrocephalus model in 8-week-old male C57BL/6J mice and evaluated it over time. We found that kaolin-injected mice showed prominent ventricular dilation, motor behavior defects at the 3-day, followed by the activation of microglia and UPRmt in the motor cortex at the 5-day. In addition, PARP-1/NF-κB signaling and apoptotic cell death appeared at the 5-day. Taken together, our findings demonstrate that activation of microglia and UPRmt occurs after hydrocephalic ventricular expansion and behavioral abnormal-ities which could be lead to apoptotic neuronal cell death, providing a new perspective on the pathogenic mechanism of hydrocephalus.

Iron-induced cellular in vitro neurotoxic responses in rat C6 cell line.

Iron is an essential metal critical for normal cellular and biochemical function and it is used as a cofactor in many vital biological pathways within the brain. However, accumulation of excess iron in brain is commonly associated with several neurodegenerative and neurotoxic adverse effects. Chronic exposure of iron leads to an increased risk for several neurodegenerative diseases. The exact mechanism of iron-induced neurotoxicity is still unclear. Therefore, our study aimed to investigate the mechanism of neurotoxic and neurodegenerative effects through in vitro exposure of ferrous sulphate in rat C6 cell line. The findings of our study have indicated that ferrous sulphate exposure may lead to induction of molecular markers of neuronal inflammation, apoptotic neuronal cell death, amyloid-beta and hyperphosphorylated tau levels. This study provides a basic mechanistic understanding of signaling pathway and biomarkers involved during iron-induced neurotoxicity.

Irisin ameliorates neuroinflammation and neuronal apoptosis through integrin \u03b1V\u03b25/AMPK signaling pathway after intracerebral hemorrhage in mice

BackgroundNeuroinflammation is a crucial factor in the development of secondary brain injury after intracerebral hemorrhage (ICH). Irisin is a newly identified myokine that confers strong neuroprotective effects in experimental ischemic stroke. However, whether this myokine can exert neuroprotection effects after ICH remains unknown. This study aimed to investigate the impact of irisin treatment on neuroinflammation and neuronal apoptosis and the underlying mechanism involving integrin αVβ5/AMPK pathway after ICH.MethodsTwo hundred and eighty-five adult (8-week-old) male C57BL/6 mice were randomly assigned to sham and ICH surgery groups. ICH was induced via intrastriatal injection of autologous blood. Irisin was administered intranasally at 30 min after ICH. To elucidate the underlying mechanism, cilengitide (a selective integrin αVβ5 inhibitor) and dorsomorphin (a selective phosphorylated AMPK inhibitor) were administered before irisin treatment. The short- and long-term neurobehavior tests, brain edema, quantitative-PCR, western blotting, Fluoro-Jade C, TUNEL, and immunofluorescence staining were performed to assess the neurofunctional outcome at the level of molecular, cell, histology, and function.ResultsEndogenous irisin and its receptor, integrin αVβ5, were increased, peaked at 24 h after ICH. irisin post-treatment improved both short- and long-term neurological functions, reduced brain edema after ICH. Interestingly, integrin αVβ5 was mainly located in the microglia after ICH, and irisin post-treatment inhibited microglia/macrophage pro-inflammatory polarization and promoted anti-inflammatory polarization. Moreover, irisin treatment inhibited neutrophil infiltration and suppressed neuronal apoptotic cell death in perihematomal areas after ICH. Mechanistically, irisin post-treatment significantly increased the expression of integrin αVβ5, p-AMPK and Bcl-2, and decreased the expression of IL-1β, TNF-α, MPO, and Bax following ICH. The neuroprotective effects of irisin were abolished by both integrin αVβ5 inhibitor cilengitide and AMPK inhibitor dorsomorphin.ConclusionsThis study demonstrated that irisin post-treatment ameliorated neurological deficits, reduced brain edema, and ameliorated neuroinflammation and neuronal apoptosis, at least in part, through the integrin αVβ5/AMPK signaling pathway after ICH. Thus, irisin post-treatment may provide a promising therapeutic approach for the early management of ICH.

NOX2-derived hydrogen peroxide impedes the AMPK/Akt-mTOR signaling pathway contributing to cell death in neuronal cells

Oxidative stress is closely related to the pathogenesis of Parkinson's disease (PD), a typical neurodegenerative disease. NADPH oxidase 2 (NOX2) is involved in hydrogen peroxide (H2O2) generation. Recently, we have reported that treatment with H2O2 and PD toxins, including 6-hydroxydopamine (6-OHDA), 1-Methyl-4-phenylpyridin-1-ium (MPP+) and rotenone, induces neuronal apoptosis by inhibiting the mTOR pathway. Here, we show that treatment with 6-OHDA, MPP+ or rotenone induced H2O2 generation by upregulating the levels of NOX2 and its regulatory proteins (p22phox, p40phox, p47phox, p67phox, and Rac1), leading to apoptotic cell death in PC12 cells and primary neurons. Inhibition of NOX2 with apocynin or diphenyleneiodonium, or knockdown of NOX2 powerfully attenuated PD toxins-evoked NOX2 and H2O2, thereby hindering activation of AMPK, inhibition of Akt/mTOR, and induction of apoptosis in neuronal cells. Pretreatment with catalase, a H2O2-scavenging enzyme, blocked the effects of PD toxins on NOX2-dependent H2O2 production, AMPK/Akt/mTOR signaling and apoptosis in the cells. Similar effects were also seen in the cells pretreated with Mito-TEMPO, a mitochondria-selective superoxide scavenger, implying a mitochondrial H2O2-dependent mechanism involved. Further research revealed that ectopic expression of constitutively active Akt or dominant negative AMPKα, or inhibition of AMPK with compound C suppressed PD toxins-induced expression of NOX2 and its regulatory proteins, as well as consequential H2O2 production and apoptosis in the cells. Taken together, these results indicate that certain PD toxins can impede the AMPK/Akt-mTOR signaling pathway leading to neuronal apoptosis by eliciting NOX2-derived H2O2 production. Our findings suggest that neuronal loss in PD may be prevented by regulating the NOX2, AMPK/Akt-mTOR signaling and/or applying antioxidants to ameliorate oxidative stress.

Loss of TAF8 causes TFIID dysfunction and p53-mediated apoptotic neuronal cell death.

Mutations in genes encoding general transcription factors cause neurological disorders. Despite clinical prominence, the consequences of defects in the basal transcription machinery during brain development are unclear. We found that loss of the TATA-box binding protein-associated factor TAF8, a component of the general transcription factor TFIID, in the developing central nervous system affected the expression of many, but notably not all genes. Taf8 deletion caused apoptosis, unexpectedly restricted to forebrain regions. Nuclear levels of the transcription factor p53 were elevated in the absence of TAF8, as were the mRNAs of the pro-apoptotic p53 target genes Noxa, Puma and Bax. The cell death in Taf8 forebrain regions was completely rescued by additional loss of p53, but Taf8 and p53 brains failed to initiate a neuronal expression program. Taf8 deletion caused aberrant transcription of promoter regions and splicing anomalies. We propose that TAF8 supports the directionality of transcription and co-transcriptional splicing, and that failure of these processes causes p53-induced apoptosis of neuronal cells in the developing mouse embryo.

Suppression of Transient Receptor Potential Melastatin 7 by Carvacrol Protects against Injured Spinal Cord by Inhibiting Blood-Spinal Cord Barrier Disruption.

When the blood-spinal cord barrier (BSCB) is disrupted after a spinal cord injury (SCI), several pathophysiological cascades occur, including inflammation and apoptotic cell death of neurons and oligodendrocytes, resulting in permanent neurological deficits. Transient receptor potential melastatin 7 (TRPM7) is involved in the pathological processes in many neuronal diseases, including traumatic brain injury, amyotrophic lateral sclerosis, parkinsonism dementia, and Alzheimer's disease. Further, carvacrol (CAR), a TRPM7 inhibitor, is known to protect against SCI by reducing oxidative stress and inhibiting the endothelial nitric oxide synthase pathway. However, the functions of TRPM7 in the regulation of BSCB homeostasis after SCI have not been examined. Here, we demonstrated that TRPM7, a calcium-mediated non-selective divalent cation channel, plays a critical role after SCI in rats. Rats were contused at T9 and given CAR (50 mg/kg) intraperitoneally immediately and 12 h after SCI, and then given the same dose once a day for 7 days. TRPM7 was found to be up-regulated after SCI in both in vitro and in vivo studies, and it was expressed in blood vessels alongside neurons and oligodendrocytes. Additionally, CAR treatment suppressed BSCB disruption by inhibiting the loss of tight junction (TJ) proteins and preserved TJ integrity. CAR also reduced apoptotic cell death and improved functional recovery after SCI by preventing BSCB disruption caused by blood infiltration and inflammatory responses. Based on these findings, we propose that blocking the TRPM7 channel can inhibit the destruction of the BSCB and it is a potential target in therapeutic drug development for use in SCI.

The involvement of TRPM2 on the MPP+-induced oxidative neurotoxicity and apoptosis in hippocampal neurons from neonatal mice: protective role of resveratrol

ABSTRACT Parkinson’s disease (PD) is an age-related chronic neurodegenerative disease. Although PD is known to be a result of damage to hippocampal neurons, its molecular mechanism has yet to be completely clarified. The neurodegeneration in hippocampal neurons has been suggested to include excessive production of reactive oxygen species (ROS). Mitochondrial dysfunction and disruption of intracellular Ca2+ homeostasis play the most important role in the increase in ROS production for the cells. Remarkably, it is stated in the literature that especially the change of Ca2+ homeostasis triggers neuronal degeneration. TRPM2 is a unique calcium-permeable nonselective cation channel, and densest in the numberless neuronal population. The current study aims to elucidate the effect of antioxidant resveratrol (Resv) on TRPM2-mediated oxidative stress (OS) induced by 1-methyl-4-phenylpyridinium (MPP) exposure in the primary mouse hippocampal neurons. The neurons were divided into four groups as Control, Resv , MPP, and MPP+ Resv. In the current results, the activation of TRPM2 was observed in primary hippocampal neurons with MPP incubation. TRPM2 channel expression levels in the MPP group increased in hippocampal neurons after MPP exposure. In addition, intracellular free Ca2+ concentration and TRPM2 channel currents were highest in MPP groups, although they were decreased by the Resv treatment. In addition, mitochondrial membrane depolarization, ROS, caspase-3, caspase-9, and apoptosis values induced by MPP decreased with resveratrol treatment. In conclusion, in our study, we observed that the dysregulation of OS-induced TRPM2 channel activation in hippocampal neurons exposed to MPP caused apoptotic cell death in neurons, while the use of resveratrol had a protective effect by reducing OS resources in the environment.

Neuroprotective Effect of Glatiramer Acetate on Neurofilament Light Chain Leakage and Glutamate Excess in an Animal Model of Multiple Sclerosis.

Axonal and neuronal pathologies are a central constituent of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), induced by the myelin oligodendrocyte glycoprotein (MOG) 35–55 peptide. In this study, we investigated neurodegenerative manifestations in chronic MOG 35–55 induced EAE and the effect of glatiramer acetate (GA) treatment on these manifestations. We report that the neuronal loss seen in this model is not attributed to apoptotic neuronal cell death. In EAE-affected mice, axonal damage prevails from the early disease phase, as revealed by analysis of neurofilament light (NFL) leakage into the sera along the disease duration, as well as by immunohistological examination. Elevation of interstitial glutamate concentrations measured in the cerebrospinal fluid (CSF) implies that glutamate excess plays a role in the damage processes inflicted by this disease. GA applied as a therapeutic regimen to mice with apparent clinical symptoms significantly reduces the pathological manifestations, namely apoptotic cell death, NFL leakage, histological tissue damage, and glutamate excess, thus corroborating the neuroprotective consequences of this treatment.