Cell Death In Brain Research Articles

Gap Junctions and Hemichannels Composed of Connexins and Pannexins Mediate the Secondary Brain Injury Following Intracerebral Hemorrhage.

Simple SummaryIntracerebral hemorrhage (ICH) is a leading medical problem without effective treatment options. The poor prognosis is attributed to the primary brain injury of the mechanical compression caused by hematoma, and secondary brain injury (SBI) that includes inflammation, glutamate excitotoxicity, oxidative stress and disruption of the blood brain barrier (BBB). Evidences suggests that gap junctions and hemichannels composed of connexins and pannexins regulate the inflammation and excitotoxicity insult in the pathological process of central nervous system disease, such as cerebral ischemia and neurodegeneration disease. In this manuscript, we discuss the fact that connexins- and pannexins-based channels could be involved in secondary brain injury of ICH, particularly through mediating inflammation, oxidative stress, BBB disruption and cell death. The details provided in this manuscript may help develop potential targets for therapeutic intervention of ICH.Intracerebral hemorrhage (ICH) is a devastating disease with high mortality and morbidity; the mortality rate ranges from 40% at 1 month to 54% at 1 year; only 12–39% achieve good outcomes and functional independence. ICH affects nearly 2 million patients worldwide annually. In ICH development, the blood leakage from ruptured vessels generates sequelae of secondary brain injury (SBI). This mechanism involves activated astrocytes and microglia, generation of reactive oxygen species (ROS), the release of reactive nitrogen species (RNS), and disrupted blood brain barrier (BBB). In addition, inflammatory cytokines and chemokines, heme compounds, and products of hematoma are accumulated in the extracellular spaces, thereby resulting in the death of brain cells. Recent evidence indicates that connexins regulate microglial activation and their phenotypic transformation. Moreover, communications between neurons and glia via gap junctions have crucial roles in neuroinflammation and cell death. A growing body of evidence suggests that, in addition to gap junctions, hemichannels (composed of connexins and pannexins) play a key role in ICH pathogenesis. However, the precise connection between connexin and pannexin channels and ICH remains to be resolved. This review discusses the pathological roles of gap junctions and hemichannels in SBI following ICH, with the intent of discovering effective therapeutic options of strategies to treat ICH.

Potential Neurogenesis and Neuroprotective Effects of Epigallocatechin-3-gallate (EGCG) in Green Tea (Camellia sinensis) Through Microglia M2 Induction Process and NLRP3 Inhibition as an Innovation for Ischemic Stroke Adjuvant Therapy: A Review

Stroke is a condition that results from the obstruction or rupture of blood arteries in the brain, cutting off blood flow to the brain and causing the death of brain cells. Stroke is divided into two types based on the cause: ischemic stroke and hemorrhagic stroke. Ischemic stroke is the most common kind of stroke, accounting for around 87% of all strokes. The high occurrence of ischemic stroke has a wide-ranging influence on society. Because ischemic stroke still has a high prevalence and limited treatment options, a therapeutic breakthrough that can assist reduce mortality and morbidity from stroke, particularly ischemic stroke, is needed. Consuming green tea (Camellia sinensis), which has neurogenetic and neuroprotective benefits, is one of the advances that can be used. This literature was compiled through online searches using Pubmed, Sciencedirect, NIH NCBI, and Google Scholar instruments. It is known that green tea with the active ingredient Epigallocatechin-3-gallate (EGCG) has the potential to induce neurogenesis in ischemic conditions by inducing microglia to polarize to M2 and can inhibit pro-inflammatory mediators through inhibition of NOD-like Receptor Protein-3 (NLRP3) so that the pyroptosis process will also be inhibited, in this way EGCG also has the potential to become an ingredient that provides a neuroprotective effect. These two major processes will aid in the recovery of ischemic stroke patients.

Gut microbiota-mediated ferroptosis contributes to mercury exposure-induced brain injury in common carp.

Mercury is a heavy metal, which causes irreversible toxicity to fish and is found in aquatic environments around the world. The purpose of this study was to investigate the relative mechanism of mercury exposure on brain injury in common carp. The results showed that mercury exposure could induce brain injury and memory loss in common carp. Meanwhile, mercury exposure could induce neuronal ferroptosis. The ferroptosis inhibitor ferrostatin-1 attenuated mercury-induced brain injury. However, in an in vitro study, mercury did not induce ferroptosis, and ferrostatin-1 did not attenuate mercury-induced common carp brain cell death. Therefore, we speculated that mercury exposure-induced ferroptosis might occur through other pathways. Studies have shown that the gut microbiota contributes to the pathological process of heavy metal-induced injury. Therefore, we detected the effects of mercury exposure on the gut microbiota composition. The results showed that the composition and diversity of the gut microbiota were affected by mercury chloride. Surprisingly, we found that the abundance of Aeromonas, one of the most important pathogenic bacteria of fish, increased significantly. Subsequently, we isolated Aeromonas hydrophila from mercury-exposed carp and these bacteria could lead to brain injury and ferroptosis in common carp. These results suggested that mercury exposure-induced brain injury partly by increasing intestinal A. hydrophila, which led to ferroptosis in common carp.

L6H21 protects against cognitive impairment and brain pathologies via toll-like receptor 4-myeloid differentiation factor 2 signalling in prediabetic rats.

Chronic high-fat diet (HFD) intake instigates prediabetes and brain pathologies, which include cognitive decline and neuroinflammation. The myeloid differentiation factor 2 (MD-2)/toll-like receptor 4 (TLR4) complex plays a pivotal role in neuroinflammation. The MD-2 inhibitor (L6H21) reduces systemic inflammation and metabolic disturbances in HFD-induced prediabetes. However, the potential role of L6H21, and its comparison with metformin, on brain pathologies in HFD-induced prediabetes has never been investigated. Male Wistar rats were given either a normal diet (ND) (n = 8) or a HFD (n = 104) for 16 weeks. At the 13th week, ND-fed rats were given a vehicle, whereas HFD-fed rats were randomly divided into 13 subgroups. Each subgroup was given vehicle, L6H21 (three doses) or metformin (300-mg·kg-1 ·day-1 ) for 1, 2 or 4 weeks. Metabolic parameters, cognitive function, brain mitochondrial function, brain TLR4-MD-2 signalling, microglial morphology, brain oxidative stress, brain cell death and dendritic spine density were investigated. HFD-fed rats developed prediabetes, neuroinflammation, brain pathologies and cognitive impairment. All doses of L6H21 and metformin given to HFD-fed rats at 2 and 4 weeks attenuated metabolic disturbance. In rats, L6H21 and metformin restored cognition and attenuated brain pathologies dose and time-dependently. These results indicate a neuroprotective role of MD-2 inhibitor in a model of prediabetes.

Assessment of genetic modulators in cerebrospinal fluid levels of YKL‐40, and C‐reactive protein: An association with Alzheimer disease

AbstractBackgroundAlzheimer's disease (AD) is one of the most complex progressive neurological diseases that cause memory loss and cognitive deterioration owing to the death of brain cells. Some potential biomarkers have been discovered in cerebrospinal fluid (CSF) which could help in the prediction of AD. These biomarkers are either associated with amyloid pathology or tau pathology. But some of the biomarkers are also associated with neuro‐Inflammation, which is the third potential event associated with AD pathogenesis[i]. The levels of YKL‐40 and C‐Reactive Protein(CRP) in CSF are the biomarkers, which are found to be associated with AD[ii]. In this study, we are investigating more about the roles of these biomarkers in AD pathogenesis.MethodThe analysis was performed on the DELCODE dataset (n=311). The findings were validated in ADNI(n=277) and requested the independent cohort ACE (n=543) to contribute to our study in meta‐analysis. The Z‐score is produced and utilized as a phenotype with sex, age, 3 Principal Component Analysis, and diagnosis as covariates in linear regression. Furtheron, we used DELCODE, ADNI, and ACE summary statistics to run random and fixed‐effect models for the meta‐analysis.ResultFollowing the study, we discovered the genetic variants of YKL‐40, and CRP with genome‐wide significant P‐values (5 x 10‐8) and evidence of connection in all datasets. In these biomarkers, however, including diagnosis as a covariate plays important role. All of the biomarkers' lambda values indicate that there is no inflation in the analysis(λ = 1.0). There was no discernible difference in age or gender. According to the meta‐analysis the genome‐wide significant loci linked with YKL‐40 appear to be in the region of chr1 and chr3; and for CRP in chr6 and chr19.ConclusionOur findings imply that the important SNPs linked to these biomarkers are found in protein‐coding areas and are connected with inflammation. In the CSF of people with AD, levels of YKL40, and CRP are higher than in healthy people. Innate immune responses and neuro‐inflammatory signaling pathways are both affected by these proteins. Taken together, these findings emphasize the importance of comprehending the complexities of AD.

Modulation of gene expression on a transcriptome-wide level following human neural stem cell transplantation in aged mouse stroke brains

IntroductionNeural stem cell (NSC) transplantation offers great potential for treating ischemic stroke. Clinically, ischemia followed by reperfusion results in robust cerebrovascular injury that upregulates proinflammatory factors, disrupts neurovascular units, and causes brain cell death. NSCs possess multiple actions that can be exploited for reducing the severity of neurovascular injury. Our previous studies in young adult mice showed that human NSC transplantation during the subacute stage diminishes stroke pathophysiology and improves behavioral outcome. MethodsWe employed a well-established and commonly used stroke model, middle cerebral artery occlusion with subsequent reperfusion (MCAO/R). Here, we assessed the outcomes of hNSC transplantation 48 h post-MCAO (24 h post-transplant) in aged mouse brains in response to stroke because aging is a crucial risk factor for cerebral ischemia. Next, we tested whether administration of the integrin α5β1 inhibitor, ATN-161, prior to hNSC transplantation further affects stoke outcome as compared with NSCs alone. RNA sequencing (RNA-seq) was used to assess the impact of hNSC transplantation on differentially expressed genes (DEGs) on a transcriptome-wide level. ResultsHere, we report that hNSC-engrafted brains with or without ATN-161 showed significantly reduced infarct size, and attenuated the induction of proinflammatory factors and matrix metalloproteases. RNA-seq analysis revealed DEGs and molecular pathways by which hNSCs induce a beneficial post-stroke outcome in aged stroke brains. 811 genes were differentially expressed (651 downregulated and 160 upregulated) in hNSC-engrafted stroke brains. Functional pathway analysis identified enriched and depleted pathways in hNSC-engrafted aged mouse stroke brains. Depletion of pathways following hNSC-engraftment included signaling involving neuroinflammation, acute phase response, leukocyte extravasation, and phagosome formation. On the other hand, enrichment of pathways in hNSC-engrafted brains was associated with PPAR signaling, LXR/RXR activation, and inhibition of matrix metalloproteases. Hierarchical cluster analysis of DEGs in hNSC-engrafted brains indicate decreased expression of genes encoding TNF receptors, proinflammatory factors, apoptosis factors, adhesion and leukocyte extravasation, and Toll-like receptors. ConclusionsOur study is the first to show global transcripts differentially expressed following hNSC transplantation in the subacute phase of stroke in aged mice. The outcome of our transcriptome study would be useful to develop new therapies ameliorating early-stage stroke injury.

Alzheimer’s drug candidate has mixed results

The small South San Francisco firm Cortexyme has an interesting theory about Alzheimer’s disease. The firm was founded based on evidence that a bacterium called Porphyromonas gingivalis —best known for causing gingivitis—infects brain cells, eats them from the inside out, and leaves a wake of destruction and inflammation that contributes to brain cell death and memory loss. Now the company has its first results from a large clinical trial. It tested a drug candidate called atuzaginstat, which inhibits gingipains, protein-chomping enzymes made by P. gingivalis that have been found in the brains of people who died from Alzheimer’s disease. The Phase 2/3 trial looked at 643 people with mild to moderate Alzheimer’s disease. The drug did not significantly slow their cognitive or functional decline. Within a day of announcing the results, Cortexyme saw its stock fall by 75%. But the company isn’t giving up on the drug. About one-third of

Decoding the Transcriptional Response to Ischemic Stroke in Obese and Non-obese Mice Brain.

Ischemic Stroke (IS) is a serious cerebrovascular disease, which leads to irreversible damage or death of brain cells. Effective control of stroke risk factors can effectively reduce the incidence of IS. However, there was an "obesity paradox" about the relationship between obesity and the prognosis of IS, in which obesity would not bring worse outcomes than non-obese IS patients. Herein, we aimed to investigate the transcriptional response to IS in obese and nonobese mice brain via RNA-Seq technology. The datasets of obese and non-obese mice with/without IS were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between Control and Obesity (DEGsObesity) and between Obesity and Obese-Stroke (DEGsObese-Stroke) were identified. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and Protein-Protein Interaction (PPI) network analysis were performed to predict the function of DEGs. 28 and 109 DEGs were screened in DEGsObesity and DEGsObese-Stroke, respectively. Significantly, in the top 10 key-genes of DEGsObese-Stroke (Tnf, Lgals3, Serpinb2, Ly6c2, Chil3, Clec4e, Mmp3, Mefv, Spn, Tlr8), Tnf and Mefv were involved in the NOD-like receptor signaling pathway, which was consistent with KEGG pathway enrichment results. And Chil3, as a mononuclear cell marker, was significantly elevated in Obese-Stroke compared with Stroke, suggesting mononuclear cell, rather than other peripheral immune cells, infiltrated into the brain of Obese-stroke. Hence, we concluded that obesity could affect the brain microenvironment at the transcriptome level and Stroke after obesity could lead to more changes in NOD-like receptor signaling pathway and monocyte infiltration, compared with non-obese Stroke.

Hypoxia Tolerant Species: The Wisdom of Nature Translated into Targets for Stroke Therapy.

Human neurons rapidly die after ischemia and current therapies for stroke management are limited to restoration of blood flow to prevent further brain damage. Thrombolytics and mechanical thrombectomy are the available reperfusion treatments, but most of the patients remain untreated. Neuroprotective therapies focused on treating the pathogenic cascade of the disease have widely failed. However, many animal species demonstrate that neurons can survive the lack of oxygen for extended periods of time. Here, we reviewed the physiological and molecular pathways inherent to tolerant species that have been described to contribute to hypoxia tolerance. Among them, Foxo3 and Eif5A were reported to mediate anoxic survival in Drosophila and Caenorhabditis elegans, respectively, and those results were confirmed in experimental models of stroke. In humans however, the multiple mechanisms involved in brain cell death after a stroke causes translation difficulties to arise making necessary a timely and coordinated control of the pathological changes. We propose here that, if we were able to plagiarize such natural hypoxia tolerance through drugs combined in a pharmacological cocktail it would open new therapeutic opportunities for stroke and likely, for other hypoxic conditions.

Histone Deacetylases and Their Isoform-Specific Inhibitors in Ischemic Stroke.

Cerebral ischemia is the second leading cause of death in the world and multimodal stroke therapy is needed. The ischemic stroke generally reduces the gene expression due to suppression of acetylation of histones H3 and H4. Histone deacetylases inhibitors have been shown to be effective in protecting the brain from ischemic damage. Histone deacetylases inhibitors induce neurogenesis and angiogenesis in damaged brain areas promoting functional recovery after cerebral ischemia. However, the role of different histone deacetylases isoforms in the survival and death of brain cells after stroke is still controversial. This review aims to analyze the data on the neuroprotective activity of nonspecific and selective histone deacetylase inhibitors in ischemic stroke.

Postmortem mitochondrial membrane permeability transition assessment of apoptotic cell death in brain and liver of insulin resistant, ovariectomised rats.

The adverse alterations in mitochondrial functions can affect neuronal function negatively, as they play a crucial role in neuronal plasticity and death. Direct measurements of mitochondrial activity, including membrane potential and ATP production, are not easily achieved in post-mortem brain and liver samples because most organ functions cease to work after death; in fact, with increasing post-mortem intervals (PMI), the brain and liver tissues deteriorate rapidly. Standard procedures of mitochondria isolation, protein determination expressed as BSA equivalent, and spectrophotometric assessment of pore opening at 540 nm were employed. Our results showed that (a) intact mitochondria may be isolated from rat brain and liver of these rats after storage in animal body (in situ) at −20 °C for 7 days (168 h, post-mortem), (b) some population of these mitochondria can still take up exogenous Ca2+ and (c) they can still resist osmotically induced large amplitude swelling in a suitable buffer. The need for mitochondrial purity, structural integrity and abundance for functional studies are common hindrances that can encumber mitochondrial research. Therefore, this study is significant to have shown that PMI up to 7 days did not extensively, diminish MMPT pore status in normal and diabetic, ovariectomised rats. This can be relevant for forensic data mining.

Inhibition of Methamphetamine-Induced Cytotoxicity in the U87-Cell Line by Atorvastatin-Conjugated Carbon Nanotubes.

In biological systems, carbon nanotubes can enhance the biological effects of drugs and reduce their side effects. Methamphetamine (METH) is a stimulant drug that induces cell death in various cell types, primarily neural cells. On the other hand, specific doses of atorvastatin (ATO) can stimulate cell growth and inhibit cell death in different cell lines. This study aimed to investigate the improvement effect of ATO@single-walled carbon nanotube (SWCNT) on METH-induced cell cytotoxicity in the U87 glioblastoma cell line. In this study, cells were cultured in 10mM of METH during the cell treatment with 0-10nM of ATO and ATO@SWCNT. The conjugated drugs to SWCNT as Van der Waals were detected using field emission scanning electron microscopy, Fourier transform-infrared spectroscopy, and other analyses. Then, the in vitro proliferating of ATO@SWCNT was explored against glioblastoma cells compared to pure ATO. This examine was performed using methyl thiazole tetrazolium approach, terminal deoxynucleotidyl transferase deoxy uridine-triphosphate nick end labeling assay, caspase-3 method, lactate dehydrogenase assay, and RH-123 assay with 10mM METH. The results obtained from transmission electron microscopy analysis showed the average size of 50nm for ATO@SWCNT. This study indicated that U87 cells, which were exposed to METH and suffered cell death, were severely reduced in the presence of ATO, especially ATO@SWCNT (for its anti-apoptotic effect), but they survived. This study suggests that ATO, which was primarily used to reduce blood lipids, can significantly reduce brain cell death. The findings of this study indicate that by using SWCNT, more drugs can reach the target cells. This method reduces the total amount of required medication and shows a more beneficial therapeutic effect.

Evaluation of the Neuroprotective Effect of Magnesium-Bis-(2-Aminoethanesulfonic)-Butanedioate in Simulated Ischemic Stroke in Rats.

Sudden loss of blood flow to an area of the brain causes ischemic stroke, which leads to the loss of nerve function in the brain. The brain tissue leads to the death of brain cells in less than a few minutes due to the lack of oxygen and nutrients. This study aimed to evaluate the effectiveness of pharmacological correction of the consequences of ischemic stroke with a new derivative of taurine magnesium-bis-(2-aminoethanesulfonic)-butanedioate under laboratory code LKHT 3-17 in rats. The ischemic stroke was simulated by electrocoagulation of the right middle cerebral artery. The assessment of lethality, neurological status, locomotor, exploratory behavior, and morphological pattern of the brain damage was carried out on the 1st, 3rd, and 7th day after the pathology simulation. Neurological deficit was determined by the McGrow stroke index scale. The locomotor and exploratory behavior was evaluated using the Acti-track software and hardware complex. When assessing the morphological changes in the brain, attention was paid to two criteria, including the average thickness of the brain cortex and the number of neurons without degenerative changes. The substances were administered 60 minutes before the start of surgery. The animals were divided into an intact group (n=20); ischemic stroke simulation group without pharmacological correction (n=50); a group with correction of the ischemic stroke with taurine at the dose of 50 mg/kg (n=50); and a group with correction of ischemic stroke with magnesium-bis-(2-aminoethanesulfonic)-butadioate (LKHT 3-17) at the dose of 150 mg/kg (n=50).LHT 3-17 (150 mg/kg) and taurine (50 mg/kg) reduced lethality by 1.55 and 1.47 times, respectively, on the 7th day after stroke, compared to the control group (P<0.05). In parallel, an effective correction of neurological deficit was found for LKHT 3-17 and taurine to 4.0±0.8 and 7.6±0.9, respectively, on the 3rd day in contrast to the control of 8.1±0.8 points. The locomotor and exploratory behavior was most significantly different on the 1st and 7th days and was accompanied by a significant increase in the speed of movement under the influence of LKHT3-17 to 20 and 20 conventional units, compared to the control of 7 and 5 cu. On the 1st day, the thickness of the cortex was 1877.3±43.3 µm in the control group, and 1531.8±39.1 µm in the LKHT 3-17 group. The number of neurons without neurodegenerative changes prevailed in the group administered with LHT 3-17 (19.3±4.3), and the lowest number was observed in the group without pharmacological correction of the pathology (14.3±3.7).LKHT 3-17 at a dose of 150 mg/kg is more effective than taurine 50 mg/kg in protecting nerve activity in experimental ischemic stroke and reducing lethality, minimizing nerve defects, reducing volume, accelerating the process of tissue repair, helping stroke, and activating the regenerative processes.

Na+/K+-ATPase activity is regionally regulated by acute hypoxia in naked mole-rat brain

Matching ATP supply and demand is key to neuronal hypoxia-tolerance and failure to achieve this balance leads to excitotoxic cell death in most adult mammalian brains. Ion pumping is the most energy-demanding process in the brain and some hypoxia-tolerant vertebrates coordinately down-regulate ion movement across neuronal membranes to reduce the workload of energy-expensive ion pumps, and particularly the Na+/K+-ATPase. Naked mole-rats are among the most hypoxia-tolerant mammals and achieve a hypometabolic state while maintaining brain [ATP] during severe hypoxia; however, whether ionic homeostasis is plastic in naked mole-rat brain is unknown. To examine this question, we exposed animals to 4 h of normoxia or moderate or severe hypoxia (11 or 3% O2, respectively) and measured changes in brain Na+/K+-ATPase activity. We found that 1) whole body metabolic rate decreased ∼25 and 75% in moderate and severe hypoxia, respectively, and 2) Na+/K+-ATPase activity decreased ∼50% in forebrain but increased 2-fold in cerebellum and was unchanged in brainstem. These results indicate that naked mole-rats acutely modulate brain energy demand in a region-specific manner to prioritize energy usage by the cerebellum. This may support exploration, navigation, and escape behaviours, while also enabling ATP savings when encountering hypoxia in nature.

Human Milk Oligosaccharide 2'-Fucosyllactose Induces Neuroprotection from Intracerebral Hemorrhage Stroke.

Intracerebral hemorrhage (ICH) occurs when brain blood vessels rupture, causing inflammation and cell death. 2-Fucosyllactose (2FL), a human milk oligosaccharide, has potent antiapoptotic and anti-inflammatory effects. The purpose of this study was to examine the protective effect of 2FL in cellular and rodent models of ICH. Hemin was added to a primary rat cortical neuronal and BV2 microglia coculture to simulate ICH in vitro. IBA1 and MAP2 immunoreactivities were used to determine inflammation and neuronal survival. Hemin significantly increased IBA1, while it reduced MAP2 immunoreactivity. 2FL significantly antagonized both responses. The protective effect of 2FL was next examined in a rat ICH model. Intracerebral administration of type VII collagenase reduced open-field locomotor activity. Early post-treatment with 2FL significantly improved locomotor activity. Brain tissues were collected for immunohistochemistry and qRT-PCR analysis. 2FL reduced IBA1 and CD4 immunoreactivity in the lesioned striatum. 2FL downregulated the expression of ER stress markers (PERK and CHOP), while it upregulated M2 macrophage markers (CD206 and TGFβ) in the lesioned brain. Taken together, our data support that 2FL has a neuroprotective effect against ICH through the inhibition of neuroinflammation and ER stress. 2FL may have clinical implications for the treatment of ICH.

Phenothiazine Inhibits Neuroinflammation and Inflammasome Activation Independent of Hypothermia After Ischemic Stroke.

A depressive or hibernation-like effect of chlorpromazine and promethazine (C + P) on brain activity was reported to induce neuroprotection, with or without induced-hypothermia. However, the underlying mechanisms remain unclear. The current study evaluated the pharmacological function of C + P on the inhibition of neuroinflammatory response and inflammasome activation after ischemia/reperfusion. A total of 72 adult male Sprague-Dawley rats were subjected to 2h middle cerebral artery occlusion (MCAO) followed by 6 or 24h reperfusion. At the onset of reperfusion, rats received C + P (8mg/kg) with temperature control. Brain cell death was detected by measuring CD68 and myeloperoxidase (MPO) levels. Inflammasome activation was measured by mRNA levels of NLRP3, IL-1β, and TXNIP, and protein quantities of NLRP3, IL-1β, TXNIP, cleaved-Caspase-1, and IL-18. Activation of JAK2/STAT3 pathway was detected by the phosphorylation of STAT3 (p-STAT3) and JAK2 (p-JAK2), and the co-localization of p-STAT3 and NLRP3. Activation of the p38 pathway was assessed with the protein levels of p-p38/p38. The mRNA and protein levels of HIF-1α, FoxO1, and p-FoxO1, and the co-localization of p-STAT3 with HIF-1α or FoxO1 were quantitated. As expected, C + P significantly reduced cell death and attenuated the neuroinflammatory response as determined by reduced CD68 and MPO. C + P decreased ischemia-induced inflammasome activation, shown by reduced mRNA and protein expressions of NLRP3, IL-1β, TXNIP, cleaved-Caspase-1, and IL-18. Phosphorylation of JAK2/STAT3 and p38 pathways and the co-localization of p-STAT3 with NLRP3 were also inhibited by C + P. Furthermore, mRNA levels of HIF-1α and FoxO1 were decreased in the C + P group. While C + P inhibited HIF-1α protein expression, it increased FoxO1 phosphorylation, which promoted the exclusion of FoxO1 from the nucleus and inhibited FoxO1 activity. At the same time, C + P reduced the co-localization of p-STAT3 with HIF-1α or FoxO1. In conclusion, C + P treatment conferred neuroprotection in stroke by suppressing neuroinflammation and NLRP3 inflammasome activation. The present study suggests that JAK2/STAT3/p38/HIF-1α/FoxO1 are vital regulators and potential targets for efficacious therapy following ischemic stroke.

Blockage of Fc Gamma Receptors Alleviates Neuronal and Microglial Toxicity Induced by Palmitic Acid.

Palmitic acid (PA) promotes brain pathologies including Alzheimer's disease (AD)-related proteins, neuroinflammation, and microglial activation. The activation of neurons and microglia via their Fc gamma receptors (FcγRs) results in producing inflammatory cytokines. To investigate the expression of FcγRs, FcγR signaling proteins, AD-related proteins, proinflammatory cytokines, and cell viability of neurons and microglia in association with PA exposure as well as the effects of FcγR blockade on these parameters in response to PA. 200 and 400μM PA-conjugated BSA were applied to SH-SY5Y and HMC3 cells for 24 h. For FcγR blockage experiment, both cells were exposed to FcγR blocker before receiving of 200 and 400μM of PA-conjugated BSA for 24 h. PA significantly increased AD-related proteins, including Aβ and BACE1, as well as increasing TNFα, IL-1β, and IL-6 in SH-SY5Y and HMC3 cells. However, the p-Tau/Tau ratio was only increased in SH-SY5Y cells. These results were associated with an increase in FcγRs activation and a decrease in cell viability in both cell types. FcγRs blockage diminished the activation of FcγR in SH-SY5Y and HMC3 cells. Interestingly, blocking FcγRs before PA exposure reduced the increment of AD-related proteins, proinflammatory cytokines caused by PA. FcγRs blocking also inhibits cell death for 23%of SH-SY5Y cells and 64%of HMC3 cells, respectively. These findings suggest that PA is a risk factor for AD via the increased AD-related pathologies, inflammation, FcγRs activation, and brain cell death, while FcγR blockage can alleviate these effects.

Advance Directives and Research Advance Directives

Advance Directives and Research Advance Directives

The Role of Post-Translational Acetylation and Deacetylation of Signaling Proteins and Transcription Factors after Cerebral Ischemia: Facts and Hypotheses

Histone deacetylase (HDAC) and histone acetyltransferase (HAT) regulate transcription and the most important functions of cells by acetylating/deacetylating histones and non-histone proteins. These proteins are involved in cell survival and death, replication, DNA repair, the cell cycle, and cell responses to stress and aging. HDAC/HAT balance in cells affects gene expression and cell signaling. There are very few studies on the effects of stroke on non-histone protein acetylation/deacetylation in brain cells. HDAC inhibitors have been shown to be effective in protecting the brain from ischemic damage. However, the role of different HDAC isoforms in the survival and death of brain cells after stroke is still controversial. HAT/HDAC activity depends on the acetylation site and the acetylation/deacetylation of the main proteins (c-Myc, E2F1, p53, ERK1/2, Akt) considered in this review, that are involved in the regulation of cell fate decisions. Our review aims to analyze the possible role of the acetylation/deacetylation of transcription factors and signaling proteins involved in the regulation of survival and death in cerebral ischemia.

Neuroprotective effects of theobromine in transient global cerebral ischemia-reperfusion rat model

Transient global cerebral ischemia (tGCI) is a cerebrovascular disorder characterized by a brief decline in blood flow, neurological deficits, and is often predictive of stroke. Theobromine (TBR) is consumed worldwide in chocolates, tea, and cocoa products. TBR is a natural stimulant and vasoactive alkaloid that may protect against ischemic injury. In this study, neuroprotective potential of theobromine (TBR) was evaluated in 2-vessel occlusion transient global cerebral ischemia-reperfusion (tGCI/R) rat model. Rats were treated with TBR (50, 100 mg/kg, p.o.) for 7 successive days, and subjected to bilateral common carotid artery occlusion (20 min) or sham surgery after last dose of TBR. Severe neurological deficits accompanied by brain infarction, blood-brain barrier abnormalities, and oedema were noted in rats subjected to tGCI/R, and these effects were prevented by TBR. TBR protected against lipid peroxidation and enhanced glutathione level in brain against tGCI/R. TBR pre-treatment for 7 days prevented tGCI/R induced cell death (lactate dehydrogenase, caspase-3), vascular injury (MMP-9), and inflammation (TNF-α, NFκB) in rat whole brain. TBR protected against glutamate excitotoxicity and GABAergic decline in the brain of rats against tGCI/R injury. Findings of this study showed that TBR can alleviate chances of stroke by preventing acute episodes of cerebral ischemia.