The dual function of microglial polarization and its treatment targets in ischemic stroke

Suppressing TLR4 alleviates cerebral injury in heatstroke rats through the modulation of microglial polarization

OBJECTIVE

This study aims to explore the neuroprotective effects of inhibiting TLR4 on brain damage resulting from heatstroke (HS) and to clarify the underlying molecular mechanisms involved.

METHODS

In this study, we successfully established a HS rat model. The TLR4 antagonist TAK-242 was administered to evaluate its impact on neurological dysfunction, brain edema, learning and memory deficits, and histopathological alterations in the hippocampus.

RESULTS

The inhibition of TLR4 using TAK-242 led to a significant reduction in neurological dysfunction and brain edema in rats subjected to HS. Additionally, TAK-242 improved learning and memory impairments associated with HS and alleviated histopathological changes observed in the hippocampus. The treatment also resulted in a decrease in CD68-positive microglia and reduced expression levels of iNOS and TNF-α, while increasing CD206-positive cells and the expression of Arg-1 and IL-10. Furthermore, TAK-242 effectively reversed the elevated protein levels of TLR4, MyD88, and NF-κB induced by HS.

CONCLUSION

These findings indicate that TLR4 inhibition through TAK-242 may be a promising therapeutic strategy for neuroprotection in HS by modulating microglial polarization.

ClC-3-depedent polarization of microglia protects against cerebral ischemic injury in mice

Polarization of microglia has attracted great attention in ischemic stroke. Emerging evidence suggests that chloride channel 3 (ClC-3) is involved in inflammatory responses and stroke. However, the link between ClC-3 and polarization of microglia in ischemic stroke remains unclear. Herein, we found both cerebral ischemia and oxygen-glucose deprivation (OGD) induced a significant upregulation of ClC-3 in microglia. While knockdown of ClC-3 markedly increased nuclear factor kappa B (NF-κB) and CD86, and decreased CD206 in BV-2 cells under OGD conditions, facilitating them to shift into a M1-like phenotype. Furthermore, ClC-3 knockout significantly aggravated infarct volume and neurological deficits, accompanied by increased activated microglia in the peri-infarct area 1 day after cerebral ischemia. By contrast, ClC-3 overexpression obviously suppressed nuclear translocation of NF-κB, decreased OGD-induced elevated mRNA levels of TNF-α, IL-1β and IL-10, and enhanced M2-like markers (Arg1, CD206, and TREM2) in microglia, leading to alleviated infarct volume and neurological deficits. While ClC-3 overexpression could not reverse a transformation from M1-like phenotype to M2-like polarization in presence of lipopolysaccharide (LPS) and interferon gamma (IFNγ) treatment for 24 h. Collectively, our findings indicate that ClC-3-dependent polarization of microglia is critically important for protecting against cerebral ischemia injury, suggesting ClC-3 is a promising therapeutic target for ischemic stroke.

Neuroprotective mechanisms of microglia in ischemic stroke: a review focused on mitochondria

Stroke encompasses a range of cerebrovascular disorders characterized by high morbidity, disability, and mortality, with ischemic stroke being the predominant type. This condition imposes significant socio-economic and healthcare burdens, and therapeutic options are currently limited. Microglia, the brain's resident immune cells, are rapidly activated following stroke-induced injury and play a pivotal role in the pathogenesis of neuroinflammation and ischemic tissues. Mitochondria participates in and influences the pathological processes of ischemic stroke, including oxidative stress, modulation of microglia phenotype, and axonal regenerative function, and is an essential and often overlooked target in the clinical management of stroke. This paper reviews recent advancements in research on microglia in ischemic stroke, specifically focusing on the contribution of the mitochondria, providing a reference for selecting therapeutic targets and guiding future research directions.

Development and in vitro evaluation of biomimetic injectable hydrogels from decellularized human nerves for central nervous system regeneration

Injuries to the central nervous system (CNS) often lead to persistent inflammation and limited regeneration. This study developed a clinically relevant injectable hydrogel derived from decellularized human peripheral nerves, with mechanical properties biomimicking native CNS tissue. Using a modified Hudson method, human sciatic nerves were decellularized, effectively removing immunogenic cellular debris while retaining the extracellular matrix. Two delipidation solvents, dichloromethane: ethanol (2:1 v/v) and n-hexane: isopropanol (3:1 v/v), were evaluated, with the former achieving optimal lipid removal and better digestion. The resulting solution was crosslinked with genipin, forming an injectable hydrogel (iHPN) that gelled within 12 min at 37 °C and exhibited mechanical stiffness of approximately 400 Pa. Human astrocytes, human microglial cell clone 3 (HMC3), and mouse RAW 264.7 macrophages were cultured individually within iHPN, with lipopolysaccharide (LPS) added to mimic CNS inflammation following injury. Compared to LPS-activated cells on tissue culture plates (TCP), astrocytes within iHPN maintained a quiescent state, as evidenced by reduced GFAP expression and IL-1β secretion. RAW 264.7 and HMC3 cells in iHPN displayed an anti-inflammatory phenotype, as shown by increased CD206 and decreased CD86/CD68 expression, along with higher IL-4 and lower TNF-α/IL-1β secretion. Human SH-SY5Y neuroblastoma cells exhibited higher viability and improved neuronal differentiation in iHPN compared to TCP. Human brain neurons had higher neuronal differentiation within iHPN compared to TCP or collagen hydrogels. Overall, iHPN is a novel injectable hydrogel that has potential for minimally invasive CNS applications, such as a carrier for cell or drug delivery and/or a biomaterial to support axonal growth.

Long Noncoding RNA ISA1 Protects Against Ischemic Brain Damage by Promoting the Transformation of Microglia Toward Anti-inflammatory Phenotype via the SOCS3/JAK2/STAT3 Pathway

The shift of microglia towards an anti-inflammatory phenotype has been shown to decrease neuroinflammation, improve neurological function, and is considered a potential therapeutic approach for stroke. Abnormal expression of multiple long noncoding RNA (LncRNA) has been discovered to be crucially related to the pathogenesis progress of ischemic brain injury. Here we concentrated on a novel LncRNA NR_037961.1, which we named ischemic stroke associated LncRNA1 (LncRNA ISA1). The expression of LncRNA ISA1 was notably decreased in brain tissue of middle cerebral artery occlusion (MCAO) mice. Overexpression of LncRNA ISA1 decreases cerebral infarction and brain edema, and improves cerebral blood flow and neurological outcome, promoting recovery of MCAO mice. Additionally, the neuroprotective effects that LncRNA ISA1 plays on MCAO mice are mediated by encouraging the transformation of microglia toward anti-inflammatory phenotype and alleviating neuroinflammation. LncRNA ISA1 facilitates the phenotypic transformation of microglia, closely linked to its promotion of SOCS3 expression and subsequent inhibition of the JAK2/STAT3 signaling pathway. Furthermore, downregulation of SOCS3 eliminated the effects of LncRNA ISA1 on transformation of microglia to anti-inflammatory phenotype. Our results indicate that LncRNA ISA1 promotes the anti-inflammatory polarization of microglia via regulation of the SOCS3/JAK2/STAT3 signaling pathway, and contributes to its neuroprotective effects in ischemic stroke.

Quercetin alleviates neonatal hypoxic-ischaemic brain injury by rebalancing microglial M1/M2 polarization through silent information regulator 1/ high mobility group box-1 signalling

Neonatal hypoxic-ischaemic encephalopathy (HIE) remains one of the major causes of neonatal death and long-term neurological disability. Due to its complex pathogenesis, there are still many challenges in its treatment. In our previous studies, we found that quercetin can alleviate neurological dysfunction after hypoxic-ischaemic brain injury (HIBI) in neonatal mice. As demonstrated through in vitro experiments, quercetin can inhibit the activation of the TLR4/MyD88/NF-κB signalling pathway and the inflammatory response in the microglial cell line BV2 after oxygen-glucose deprivation. However, the in-depth mechanism still needs to be further elucidated. In the present study, 7 day-old neonatal ICR mice or BV2 cells were treated with quercetin with or without the SIRT1 inhibitor EX527 via neurobehavioural, histopathological and molecular methods. In vivo experiments have shown that quercetin can significantly improve the performance of HI mice in behavioural tests, such as the Morris water maze, rotarod test and pole climbing test, and reduce HI insult-induced structural brain damage, cell apoptosis and hippocampal neuron loss. Quercetin also inhibited the immunofluorescence intensity of the microglial M1 marker CD16 + 32 and significantly downregulated the expression of the M1-related proteins iNOS, IL-1β and TNF-α. Moreover, quercetin increased the immunofluorescence intensity of the microglial M2 marker CD206 and significantly increased the expression of the M2-related proteins Arg-1 and IL-10. In addition, quercetin limits the nucleocytoplasmic translocation and release of microglial HMGB1 and further suppresses the activation of the downstream TLR4/MyD88/NF-κB signalling pathway. The above effects of quercetin are partially weakened by pretreatment with EX527. Similar results were found in in vitro experiments, and the mechanism further revealed that the rebalancing effect of quercetin on microglial polarization is achieved through the SIRT1-mediated reduction in HMGB1 acetylation levels. This study provides new and complementary insights into the neuroprotective effects of quercetin and a new direction for the treatment of neonatal HIE.

Esketamine at a Clinical Dose Attenuates Cerebral Ischemia/Reperfusion Injury by Inhibiting AKT Signaling Pathway to Facilitate Microglia M2 Polarization and Autophagy

Purpose

This study aimed to assess the protective effect of a clinical dose esketamine on cerebral ischemia/reperfusion (I/R) injury and to reveal the potential mechanisms associated with microglial polarization and autophagy.

Methods

Experimental cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult rats and simulated by oxygen-glucose deprivation (OGD) in BV-2 microglial cells. Neurological and sensorimotor function, cerebral infarct volume, histopathological changes, mitochondrial morphological changes, and apoptosis of ischemic brain tissues were assessed in the presence or absence of esketamine and the autophagy inducer rapamycin. The expression of biomarkers related to microglial M1 and M2 phenotypes in the ischemic brain tissues was determined by immunofluorescence staining and RT-qPCR, and the expression of proteins associated with autophagy and the AKT signaling pathway in the ischemic brain tissues was assayed by Western blotting.

Results

Esketamine alone and esketamine combined with rapamycin alleviated neurological impairment, improved sensorimotor function, decreased cerebral infarct volume, and mitigated tissue injury in the MCAO rats. Importantly, esketamine promoted microglial phenotypic transition from M1 to M2 in both the MCAO rats and the OGD-treated BV-2 microglia, induced autophagy, and inactivated AKT signaling. Furthermore, the effects of esketamine were enhanced by addition of autophagy inducer rapamycin.

Conclusion

Esketamine at a clinical dose attenuates cerebral I/R injury by inhibiting AKT signaling pathway to facilitate microglial M2 polarization and autophagy. Furthermore, esketamine combined autophagy inducer can provide an improved protection against cerebral I/R injury. Thus, this study provides new insights into the neuroprotective mechanisms of esketamine and the potential therapeutic strategies of cerebral I/R injury.

Polymer-Formulated Nerve Growth Factor Shows Effective Therapeutic Efficacy for Cerebral Microinfarcts

Cerebral microinfarcts represent the most prevalent form of ischemic brain injury in the elderly, particularly among those suffering from dementia, Alzheimer's disease, and vascular risk factors. Despite their commonality, effective treatments have remained elusive. Herein, a novel treatment utilizing a polymer-formulated nerve growth factor capable of crossing the blood-brain barrier is reported, which effectively reduced oxidative stress and neuronal apoptosis, reshaped microglia polarization at infarct sites, and decreased the overall microinfarct burden, leading to notable improvements in behavioral and cognitive functions in a mouse model. This work provides a promising new avenue for the treatment of cerebral microinfarcts and other neurodegenerative diseases.

Advancements in the mechanisms of Naotai formula in treating stroke: A multi-target strategy

Stroke represents a significant global health challenge, characterized by high incidence, mortality, disability, and recurrence rates, leading to substantial socioeconomic burdens. Despite advancements in acute management and prevention, effective post-stroke recovery strategies remain limited. Naotai Formula (NTF), a traditional Chinese medicine compound, has garnered attention for its potential in stroke treatment, encompassing both ischemic and hemorrhagic types. This review synthesizes recent advancements in basic and clinical research on NTF, focusing on its mechanisms of action in stroke therapy. The formula's multifaceted effects include promoting neuronal regeneration, combating oxidative stress, regulating lipid metabolism, and modulating iron homeostasis. Through a multi-target approach, NTF addresses the complex pathophysiology of stroke, suggesting a promising complementary strategy for stroke recovery. Despite promising findings, further research is required to elucidate its active components, potential side effects, and optimized therapeutic protocols. The integration of traditional Chinese medicine, like NTF, with conventional treatments may enhance stroke management strategies, urging the need for high-quality clinical trials and evidence-based guidelines.

The Multifaceted Nature of Macrophages in Cardiovascular Disease

As the leading cause of mortality worldwide, cardiovascular disease (CVD) represents a variety of heart diseases and vascular disorders, including atherosclerosis, aneurysm, ischemic injury in the heart and brain, arrythmias, and heart failure. Macrophages, a diverse population of immune cells that can promote or suppress inflammation, have been increasingly recognized as a key regulator in various processes in both healthy and disease states. In healthy conditions, these cells promote the proper clearance of cellular debris, dead and dying cells, and provide a strong innate immune barrier to foreign pathogens. However, macrophages can play a detrimental role in the progression of disease as well, particularly those inflammatory in nature. This review will focus on the current knowledge regarding the role of macrophages in cardiovascular diseases.

Role of microglia in stroke

Microglia play key roles in the post-ischemic inflammatory response and damaged tissue removal reacting rapidly to the disturbances caused by ischemia and working to restore the lost homeostasis. However, the modified environment, encompassing ionic imbalances, disruption of crucial neuron-microglia interactions, spreading depolarization, and generation of danger signals from necrotic neurons, induce morphological and phenotypic shifts in microglia. This leads them to adopt a proinflammatory profile and heighten their phagocytic activity. From day three post-ischemia, macrophages infiltrate the necrotic core while microglia amass at the periphery. Further, inflammation prompts a metabolic shift favoring glycolysis, the pentose-phosphate shunt, and lipid synthesis. These shifts, combined with phagocytic lipid intake, drive lipid droplet biogenesis, fuel anabolism, and enable microglia proliferation. Proliferating microglia release trophic factors contributing to protection and repair. However, some microglia accumulate lipids persistently and transform into dysfunctional and potentially harmful foam cells. Studies also showed microglia that either display impaired apoptotic cell clearance, or eliminate synapses, viable neurons, or endothelial cells. Yet, it will be essential to elucidate the viability of engulfed cells, the features of the local environment, the extent of tissue damage, and the temporal sequence. Ischemia provides a rich variety of region- and injury-dependent stimuli for microglia, evolving with time and generating distinct microglia phenotypes including those exhibiting proinflammatory or dysfunctional traits and others showing pro-repair features. Accurate profiling of microglia phenotypes, alongside with a more precise understanding of the associated post-ischemic tissue conditions, is a necessary step to serve as the potential foundation for focused interventions in human stroke.

Brain microvascular endothelial cell-derived exosomes transmitting circ_0000495 promote microglial M1-polarization and endothelial cell injury under hypoxia condition

Human brain microvascular endothelial cells (HBMVECs) and microglia play critical roles in regulating cerebral homeostasis during ischemic stroke. However, the role of HBMVECs-derived exosomes in microglia polarization after stroke remains unknown. We isolated exosomes (Exos) from oxygen glucose deprivation (OGD)-exposed HBMVECs, before added them into microglia. Microglia polarization markers were tested using RT-qPCR or flow cytometry. Inflammatory cytokines were measured with ELISA. Endothelial cell damage was assessed by cell viability, apoptosis, apoptosis-related proteins, oxidative stress, and angiogenic activity using CCK-8, flow cytometry, western blot, ELISA, and endothelial tube formation assay, respectively. We also established middle cerebral artery occlusion (MCAO) mice model to examine the function of circ_0000495 on stroke in vivo. Our study found that HBMVECs-Exos reduced M2 markers (IL-10, CD163, and CD206), increased M1 markers (TNF-α, IL-1β, and IL-12), CD86-positive cells, and inflammatory cytokines (TNF-α and IL-1β), indicating the promotion of microglial M1-polarization. Microglial M1-polarization induced by HBMVECs-Exos reduced viability and promoted apoptosis and oxidative stress, revealing the aggravation of endothelial cell damage. However, circ_0000495 silencing inhibited HBMVECs-Exos-induced alterations. Mechanistically, circ_0000495 adsorbed miR-579-3p to upregulate toll-like receptor 4 (TLR4) in microglia; miR-579-3p suppressed HBMVECs-Exos-induced alterations via declining TLR4; furthermore, Yin Yang 1 (YY1) transcriptionally activated circ_0000495 in HBMVECs. Importantly, circ_0000495 aggravated ischemic brain injury in vivo via activating TLR4/nuclear factor-κB (NF-κB) pathway. Collectively, OGD-treated HBMVECs-Exos transmitted circ_0000495 to regulate miR-579-3p/TLR4/NF-κB axis in microglia, thereby facilitating microglial M1-polarization and endothelial cell damage.

Recent Advances in Chemically Engineered Nanostructures Impact on Ischemic Stroke Treatment

Stroke is a serious public health problem that raises expenses for society and causes long-term impairment and death. However, due to restricted blood-brain barrier (BBB) penetration, there are few treatment alternatives for treating stroke. Recanalization techniques, neuroprotective medications, and recovery techniques are all forms of treatment. The ischemic stroke treatment window is too narrow for logical and efficient therapy, and detection is possible only in advanced stages. BBB integrity disruption, neurotoxicity, and the brief half-life of therapeutic thrombolytics are the key molecular pathogenic causes of ischemic stroke. Existing neuroprotective drugs' inability to promote the recovery of ischemic brain tissue after a stroke is another factor that contributes to the disease's progression, chronic nature, and severity. A possible approach to getting around these medication restrictions and boosting the effectiveness of therapies is nanotechnology. In order to get around these drug-related restrictions and boost the effectiveness of therapies for neurological conditions such as stroke, nanotechnology has emerged as a viable option. These problems might be avoided by using nanoparticle-based methods to create a thrombolytic medication that is safe to use after the tissue plasminogen activator (tPA) treatment window has passed. The idea of using biomimetic nanoparticles in the future for the treatment of ischemic stroke through immunotherapy and stem cell therapy is highlighted, along with recent advancements in the study of nanomaterials for ischemic stroke diagnostics and treatment.

The role of microglial activation on ischemic stroke: Modulation by fibroblast growth factors

Stroke is one of the devastating clinical conditions that causes death and permanent disability. Its occurrence causes the reduction of oxygen and glucose supply, resulting in events such as inflammatory response, oxidative stress, and apoptosis in the brain. Microglia are brain-resident immune cells in the central nervous system (CNS) that exert diverse roles and respond to pathological process after an ischemic insult. The discovery of fibroblast growth factors (FGFs) in mammals, resulted to the findings that they can treat experimental models of stroke in animals effectively. FGFs function as homeostatic factors that control cells and hormones involved in metabolism, and they also regulate the secretion of proinflammatory (M1) and anti-inflammatory (M2) cytokines after stroke. In this review, we outline current evidence of microglia activation in experimental models of stroke focusing on its ability to exacerbate damage or repair tissue. Also, our review sheds light on the pharmacological actions of FGFs on multiple targets to regulate microglial modulation and highlighted their theoretical molecular mechanisms to provide possible therapeutic targets, as well as their limitations for the treatment of stroke. DATA AVAILABILITY: Not applicable.

Role of Crosstalk between Glial Cells and Immune Cells in Blood-Brain Barrier Damage and Protection after Acute Ischemic Stroke

Blood-brain barrier (BBB) damage is the main pathological basis for acute ischemic stroke (AIS)-induced cerebral vasogenic edema and hemorrhagic transformation (HT). Glial cells, including microglia, astrocytes, and oligodendrocyte precursor cells (OPCs)/oligodendrocytes (OLs) play critical roles in BBB damage and protection. Recent evidence indicates that immune cells also have an important role in BBB damage, vasogenic edema and HT. Therefore, regulating the crosstalk between glial cells and immune cells would hold the promise to alleviate AIS-induced BBB damage. In this review, we first introduce the roles of glia cells, pericytes, and crosstalk between glial cells in the damage and protection of BBB after AIS, emphasizing the polarization, inflammatory response and crosstalk between microglia, astrocytes, and other glia cells. We then describe the role of glial cell-derived exosomes in the damage and protection of BBB after AIS. Next, we specifically discuss the crosstalk between glial cells and immune cells after AIS. Finally, we propose that glial cells could be a potential target for alleviating BBB damage after AIS and we discuss some molecular targets and potential strategies to alleviate BBB damage by regulating glial cells after AIS.

Histopathological lesions induced by stroke in the encephalon

Strokes are conditions with a high degree of morbidity and mortality worldwide. These conditions profoundly affect the quality of life of patients; in addition to physical disabilities, patients present various mental disorders, such as mood disorders, anxiety, depression, behavioral disorders, fatigue, etc. Microscopic lesions of the brain parenchyma explain the clinical symptoms and correlate with the severity of the stroke. Our study consisted of the histopathological (HP) and immunohistochemical analysis of brain fragments, collected from 23 patients, with a clinical and imagistic diagnosis of stroke, who died during hospital admission. The microscopic analysis showed that both neurons and glial cells are affected in the ischemic focus. Neuronal death in the ischemic focus was mostly caused by cell necrosis and only about 10% by apoptosis. Regarding vascular lesions, it was observed that the most frequent HP lesion of intracerebral arterioles was arteriosclerosis. The lumen of the arterioles was reduced, and the vascular endothelium had a discontinuous aspect, which indicates a change in the blood-brain barrier. Sometimes the arteriole lumen was completely obstructed, with fibrinoid necrosis in the internal and middle tunic, or with the proliferation of fibroblasts and the formation of young intraluminal connective tissue. Intraparenchymal blood capillaries in the ischemic area showed endothelium discontinuities, lumen collapse, and sometimes massive perivascular edema. As for neuroinflammation, the presence of numerous neutrophils, lymphocytes, plasma cells and macrophages was found in the ischemic focus, forming a complex and inhomogeneous cellular mixture. Of the inflammatory cells present in the ischemic focus and in the ischemic penumbra area, the most numerous were the macrophages. The HP analysis showed that neuroinflammation is very complex and different in intensity from one patient to another, most likely due to associated comorbidities, age, treatment administered until death, etc.

Inosine attenuates post-stroke neuroinflammation by modulating inflammasome mediated microglial activation and polarization

To date, various agents and molecules have been developed to treat post-stroke neuroinflammation; however, none of them are clinically successful. Post-stroke neuroinflammation is primarily attributed to microglial polarization as the generation of inflammasome complexes shifts microglia to their M1 phenotype and regulate the downstream cascade. Inosine, an adenosine derivative reported to maintain cellular energy homeostasis in stressed condition. Although, the exact mechanism is still unexplored, various studies have reported that it can stimulate axonal sprouting in different neurodegenerative diseases. Hence, our present study aims to decipher the molecular mechanism of inosine mediated neuroprotection by modulating inflammasome signaling towards altered microglial polarization in ischemic stroke. Inosine was administered intraperitoneally to male Sprague Dawley rats at 1 h post ischemic stroke and were further evaluated for neurodeficit score, motor coordination and long-term neuroprotection. Brains were harvested for infarct size estimation, biochemical assays and molecular studies. Inosine administration at 1 h post ischemic stroke decreased infarct size, neurodeficit score, and improved motor co-ordination. Normalization of biochemical parameters were achieved in the treatment groups. Microglial polarization towards its anti-inflammatory phenotype and modulation of inflammation were evident by relevant gene and protein expression studies. The outcome provides preliminary evidence of inosine mediated alleviation of post-stroke neuroinflammation via modulation of microglial polarization towards its anti-inflammatory form through regulating the inflammasome activation.

BRG1 alleviates microglial activation by promoting the KEAP1-NRF2/HO-1 signaling pathway and minimizing oxidative damage in cerebral ischemia-reperfusion

BRG1 is a key factor in the process of apoptosis and oxidative damage; however, its role in the pathophysiology of ischemic stroke is unclear. Here, we discovered that during middle cerebral artery occlusion (MCAO) reperfusion in mice, microglia were significantly activated in the cerebral cortex of the infarct area, and BRG1 expression was increased in the mouse MCAO/R model, peaking at 4 days. In microglia subjected to OGD/R, BRG1 expression increased and peaked at 12 h after reoxygenation. After ischemic stroke, in vitro changing the expression of BRG1 expression levels greatly altered the activation of microglia and the production of antioxidant and pro-oxidant proteins. Knocking down BRG1 expression levels in vitro increased the inflammatory response, promoted microglial activation, and decreased the expression of the NRF2/HO-1 signaling pathway after ischemic stroke. In contrast, overexpression of BRG1 dramatically reduced the expression of NRF2/HO-1 signaling pathway and microglial activation. Our research reveals that BRG1 reduces postischemic oxidative damage via the KEAP1-NRF2/HO-1 signaling pathway, protecting against brain ischemia/reperfusion injury. Using BRG1 as a pharmaceutical target to inhibit inflammatory responses to reduce oxidative damage may be a unique way to explore techniques for the treatment of ischemic stroke and other cerebrovascular illnesses.

Integrative Analysis of Single-Cell and Bulk Sequencing Data Depicting the Expression and Function of P2ry12 in Microglia Post Ischemia-Reperfusion Injury

P2ry12 is a microglial marker gene. Recently, increasing evidence has demonstrated that its expression levels can vary in response to different CNS disorders and can affect microglial functions, such as polarization, plasticity, and migration. However, the expression and function of P2ry12 in microglia during ischemia-reperfusion injury (IRI) remain unclear. Here, we developed a computational method to obtain microglia-specific P2ry12 genes (MSPGs) using sequencing data associated with IRI. We evaluated the change in comprehensive expression levels of MSPGs during IRI and compared it to the expression of P2ry12 to determine similarity. Subsequently, the MSPGs were used to explore the P2ry12 functions in microglia through bioinformatics. Moreover, several animal experiments were also conducted to confirm the reliability of the results. The expression of P2ry12 was observed to decrease gradually within 24 h post injury. In response, microglia with reduced P2ry12 expression showed an increase in the expression of one receptor-encoding gene (Flt1) and three ligand-encoding genes (Nampt, Igf1, and Cxcl2). Furthermore, double-labeling immunofluorescence staining revealed that inhibition of P2ry12 blocked microglial migration towards vessels during IRI. Overall, we employ a combined computational and experimental approach to successfully explore P2ry12 expression and function in microglia during IRI.

Gentamycin Rationally Repositioned to Inhibit miR-34a Ameliorates Oxidative Injury to PC12 Cells

Ischemic stroke accompanies oxidative stress and cell death in the cerebral tissue. The microRNA miR-34a plays a pivotal role in this molecular pathology. This study presents the rational repositioning of aminoglycosidic antibiotics as miR-34a antagonists in order to assess their efficiency in protecting the PC12 stroke model cells from oxidative stress occurring under cerebral ischemic conditions. A library of 29 amino-sugar compounds were screened against anticipated structural models of miR-34a through molecular docking. MiR-ligand interactions were mechanistically studied by molecular dynamics simulations and free-energy calculations. Cultured PC12 cells were treated by H₂O₂ alone or in combination with gentamycin and neomycin as selected drugs. Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) and annexin V-FITC/propidium iodate (PI) double staining assays, respectively. The expression levels of key factors involved in cell proliferation, oxidative stress, and apoptosis in treated PC12 cells were measured through a quantitative real-time polymerase chain reaction and flow cytometric annexin V-FITC/PI double staining assays. A stable and energetically favorable binding was observed for miR-34a with gentamycin and neomycin. Gentamycin pretreatments followed by H₂O₂ oxidative injury led to increased cell viability and protected PC12 cells against H₂O₂-induced apoptotic events. This study will help in further understanding how the suppression of miR-34a in neural tissue affects the cell viability upon stroke.