Janus Kinase Inhibition Ameliorates Ischemic Stroke Injury and Neuroinflammation Through Reducing NLRP3 Inflammasome Activation via JAK2/STAT3 Pathway Inhibition

Gastrodin against oxidative stress-inflammation crosstalk via inhibiting mtDNA/TLR9 and JAK2/STAT3 signaling to ameliorate ischemic stroke injury

The pathway of Janus-activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) (termed as JAK2/STAT3) plays an active role in stroke-related inflammation induced by ischemic stress. Gastrodin, the primary compound in Gastrodia elata Bl, has been identified for its notable neuroprotective effects and demonstrated to ameliorate cerebral ischemia-reperfusion but its exact mechanisms governing this defense are still unclear. This study aims to investigate whether gastrodin can regulate mitochondrial function via the JAK2/STAT3 pathway to limit cerebral ischemia-reperfusion. In vivo, gastrodin significantly reduced infarct volume, improved neurobiological function, attenuated neuronal apoptosis, oxidative stress, mitochondrial impairment, mtDNA leakage, and inflammatory responses. At the cellular level, gastrodin administration rescued OGD/R-induced cell apoptosis, oxidative stress, and mitochondrial dysfunction. Mechanistically, gastrodin notably suppressed Toll-like receptor 9 (TLR9) expression, important for the recognition of disrupted endogenous DNA to produce inflammatory reactions. Furthermore, gastrodin mitigated inflammation by inhibiting JAK2/STAT3 signaling, influencing inflammatory factors to aggravate inflammation. Notably, the effects of gastrodin were abolished by Coumermycin A1 (C-A1), a JAK2 agonist, validating the role of JAK2/STAT3 signaling. In summary, gastrodin enhances the protective effect against mitochondrial damage in ischemic stroke by inhibiting JAK2/STAT3 signaling. Gastrodin is a possible therapy for cerebral ischemia.

Jiao-tai-wan and its effective component-coptisine alleviate cognitive impairment in db/db mice through the JAK2/STAT3 signaling pathway

BACKGROUND

Cognitive impairment (CI) is now well-accepted as a complication and comorbidity of diabetes mellitus (DM), becoming a serious medical and social problem. Jiao-tai-wan (JTW), one of noted traditional Chinese medicine (TCM), showed dual therapeutic effects on DM and CI. Nevertheless, the potential mechanism is unclear.

PURPOSE

This study sought to investigate the mechanism how JTW protected against DM and CI and screen the active component in JTW.

METHODS

Db/db mice were used as mouse models. Mice were treated by gavage with 0.9 % saline (0.1 mL/10g/d), low dose of JTW (2.4 g/kg/d) or high dose of JTW (4.8 g/kg/d) for 8 weeks separately. To access the effects of JTW, the levels of OGTT, HOMA-IR, blood lipids, inflammatory cytokines in serum and hippocampus were measured, behavioral tests were conducted, and histopathological changes were observed. The mechanism exploration was performed via network pharmacology, RT-qPCR, western blot, and immunofluorescence staining (IF). The impact and mechanism of coptisine in vitro were investigated using BV2 cells induced by LPS as cellular models. In vitro experiments were conducted in two parts. The first part comprised four groups: Control group, LPS group, LPS+LCOP group and LPS+HCOP group. The second part consisted of four groups: Control group, LPS group, LPS+HCOP group, and LPS+ Fed group. The western blot and RT-qPCR methods were used to examine the changes in biomarkers of the JAK2/STAT3 signaling pathways in BV2 cells.

RESULTS

The results demonstrated that JTW could improve OGTT and HOMA-IR, reduce the serum levels of LDL-C, HDL-C, TG, and TC, restore neuronal dysfunction and synaptic plasticity, and decrease the deposition of Aβ in the hippocampus. The findings from ELISA, IF, and RT-qPCR revealed that JTW could alleviate microglial activation and inflammatory status in vivo and coptisine could play the same role in vitro. Moreover, the changes of the JAK2/STAT3 signaling pathway in LPS-induced BV2 cells or hippocampus of db/db mice were distinctly reversed by coptisine or JTW, respectively.

CONCLUSION

Our study suggested that JTW and its effective component coptisine could alleviate diabetes mellitus-related cognitive impairment, closely linked to the JAK2/STAT3 signaling pathway.

NLRP3 blockade by MCC950 suppressed osteoclastogenesis via NF-κB/c-FOS/NFATc1 signal pathway and alleviated bone loss in diabetes mellitus

Obesity and type 2 diabetes mellitus (T2DM) are linked to osteoporosis development, with obesity being a significant risk factor for T2DM. T2DM patients with obesity exhibit a higher fracture rate and often have a poor prognosis post-fracture. To address the urgent need for understanding the mechanisms of diabetic osteoporosis (DOP), research is ongoing to explore how obesity and T2DM impact bone metabolism. The NLRP3 inflammasome has been implicated in the pathogenesis of osteoporosis, and MCC950, an NLRP3 inflammasome inhibitor, has shown promise in various diseases but its role in osteoporosis remains unexplored. In this study, BMMs and BMSCs were isolated and cultured to investigate the effects of MCC950 on bone metabolism, and DOP model was used to evaluate the efficacy of MCC950 in vivo. The study demonstrated that MCC950 treatment inhibited osteoclast differentiation, reduced bone resorption capacity in BMMs without suppression for osteoblast differentiation from BMSCs. Additionally, MCC950 suppressed the activation of the NF-κB signaling pathway and downregulated key factors associated with osteoclast differentiation. Additionally, MCC950 alleviated bone loss in DOP mouse. These findings suggest that MCC950, by targeting the NLRP3 inflammasome, may have a protective role in preventing osteoporosis induced by T2DM with obesity. The study highlights the potential therapeutic implications of MCC950 in managing diabetic osteoporosis and calls for further research to explore its clinical application in high-risk patient populations.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Unraveling the protein post-translational modification landscape: Neuroinflammation and neuronal death after stroke

The impact of stroke on global health is profound, with both high mortality and morbidity rates. This condition can result from cerebral ischemia, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH). The pathophysiology of stroke involves secondary damage and irreversible loss of neuronal function. Post-translational modifications (PTMs) have been recognized as crucial regulatory mechanisms in ischemic and hemorrhagic stroke-induced brain injury. These PTMs include phosphorylation, glycosylation, ubiquitination, SUMOylation, acetylation, and succinylation. This comprehensive review delves into recent research on the PTMs landscape associated with neuroinflammation and neuronal death specific to cerebral ischemia, ICH, and SAH. This review aims to explain the role of PTMs in regulating pathologic mechanisms and present critical techniques and proteomic strategies for identifying PTMs. This knowledge helps us comprehend the underlying mechanisms of stroke injury and repair processes, leading to the development of innovative treatment strategies. Importantly, this review underscores the significance of exploring PTMs to understand the pathophysiology of stroke.

Apelin-13-Loaded Macrophage Membrane-Encapsulated Nanoparticles for Targeted Ischemic Stroke Therapy via Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Purpose

Ischemic stroke is a refractory disease wherein the reperfusion injury caused by sudden restoration of blood supply is the main cause of increased mortality and disability. However, current therapeutic strategies for the inflammatory response induced by cerebral ischemia-reperfusion (I/R) injury are unsatisfactory. This study aimed to develop a functional nanoparticle (MM/ANPs) comprising apelin-13 (APNs) encapsulated in macrophage membranes (MM) modified with distearoyl phosphatidylethanolamine-polyethylene glycol-RVG29 (DSPE-PEG-RVG29) to achieve targeted therapy against ischemic stroke.

Methods

MM were extracted from RAW264.7. PLGA was dissolved in dichloromethane, while Apelin-13 was dissolved in water, and CY5.5 was dissolved in dichloromethane. The precipitate was washed twice with ultrapure water and then resuspended in 10 mL to obtain an aqueous solution of PLGA nanoparticles. Subsequently, the cell membrane was evenly dispersed homogeneously and mixed with PLGA-COOH at a mass ratio of 1:1 for the hybrid ultrasound. DSPE-PEG-RVG29 was added and incubated for 1 h to obtain MM/ANPs.

Results

In this study, we developed a functional nanoparticle delivery system (MM/ANPs) that utilizes macrophage membranes coated with DSPE-PEG-RVG29 peptide to efficiently deliver Apelin-13 to inflammatory areas using ischemic stroke therapy. MM/ANPs effectively cross the blood-brain barrier and selectively accumulate in ischemic and inflamed areas. In a mouse I/R injury model, these nanoparticles significantly improved neurological scores and reduced infarct volume. Apelin-13 is gradually released from the MM/ANPs, inhibiting NLRP3 inflammasome assembly by enhancing sirtuin 3 (SIRT3) activity, which suppresses the inflammatory response and pyroptosis. The positive regulation of SIRT3 further inhibits the NLRP3-mediated inflammation, showing the clinical potential of these nanoparticles for ischemic stroke treatment. The biocompatibility and safety of MM/ANPs were confirmed through in vitro cytotoxicity tests, blood-brain barrier permeability tests, biosafety evaluations, and blood compatibility studies.

Conclusion

MM/ANPs offer a highly promising approach to achieve ischemic stroke-targeted therapy inhibiting NLRP3 inflammasome-mediated pyroptosis.

Endothelin-1-Induced Persistent Ischemia in a Chicken Embryo Model

Current ischemic models strive to replicate ischemia-mediated injury. However, they face challenges such as inadequate reproducibility, difficulties in translating rodent findings to humans, and ethical, financial, and practical constraints that limit the accuracy of extensive research. This study introduces a novel approach to inducing persistent ischemia in 3-day-old chicken embryos using endothelin-1. The protocol targets the right vitelline arteries, validated with Doppler blood flow imaging and molecular biology experiments. This innovative approach facilitates the exploration of oxidative stress, inflammatory responses, cellular death, and potential drug screening suitability utilizing a 3-day-old chicken embryo. Key features • This model enables the evaluation and investigation of the pathology related to persistent ischemia • This model allows for the assessment of parameters like oxidative stress, inflammation, and cellular death • This model enables quantification of molecular changes at the nucleic acid and protein levels • This model allows for the efficient screening of drugs and their targets Graphical overview.

The positive role of transforming growth factor-β1 in ischemic stroke

Ischemic stroke is one of the most disabling and fatal diseases around the world. The damaged brain tissues will undergo excessive autophagy, vascular endothelial cells injury, blood-brain barrier (BBB) impairment and neuroinflammation after ischemic stroke. However, there is no unified viewpoint on the underlying mechanism of brain damage. Transforming growth factor-β1 (TGF-β1), as a multi-functional cytokine, plays a crucial role in the intricate pathological processes and helps maintain the physiological homeostasis of brain tissues through various signaling pathways after ischemic stroke. In this review, we summarize the protective role of TGF-β1 in autophagic flux, BBB, vascular remodeling, neuroinflammation and other aspects after ischemic stroke. Based on the review, we believe that TGF-β1 could serve as a key target for treating ischemic stroke.

AD16 attenuates neuroinflammation induced by cerebral ischemia through down-regulating astrocytes A1 polarization

A1 polarization of astrocytes mediated prolonged inflammation contributing to brain injury in ischemic stroke. We have previously shown that AD16 protects against neonatal hypoxic-ischemic brain damage in vivo and oxygen-glucose deprivation in vitro. More recently, AD16 has demonstrated safety, tolerability, and favorable pharmacokinetics in a randomized controlled phase I trial. In this study, we utilized a rat model of transient middle cerebral artery occlusion (tMCAO) to explore whether the anti-inflammatory compound AD16 protects against ischemic brain injury by regulating A1 polarization and its underlying mechanisms. Our results showed that AD16 treatment significantly reduced the brain infarcted volume and improved neurological function in tMCAO rats. GO analysis results show that differential genes among the Sham, tMCAO and AD16 treatment groups are involved in the regulation of cytokine and inflammatory response. KEGG enrichment pathways analysis mainly enriched in cytokine-cytokine receptor interaction, viral protein interaction with cytokine-cytokine receptor, TNF, chemokine, NF-κB and IL-17 signaling pathway. Furthermore, AD16 treatment decreased the permeability of the blood-brain barrier and suppressed neuroinflammation. AD16 treatment also significantly reduced the polarization of A1 and inhibited NF-κB and JAK2/STAT3 signaling pathways. This study demonstrates that AD16 protects against brain injury in ischemic stroke by reducing A1 polarization to suppress neuroinflammation through downregulating NF-κB and JAK2/STAT3 signaling. Our findings uncover a potential molecular mechanism for AD16 and suggest that AD16 holds promising therapeutic potential against cerebral ischemia.

Isoquercitrin alleviates OGD/R-induced oxidative stress and impaired mitochondrial biogenesis in SH-SY5Y cells via the NRF1/TFAM pathway

Isoquercitrin (ISO) is a traditional Chinese medicine extract, that has been found to possess potent neuroprotective properties. However, its precise role in the context of ischemic stroke (IS) remains to be fully elucidated. We constructed an in vitro model of IS induced by OGD/R in SH-SY5Y cells. Cell viability, the levels of oxidative stress-related indicators (8-OHDG, MDA, SOD, GSH, and GSH-Px), ROS, and mitochondrial membrane potential were measured by using detection kits. The protein levels of GPX1, SOD, Cytc were measured. The mRNA levels of mitochondrial biogenesis-related indicators (Cytb, CO1, ND2, ND5, and ND6), and mtDNA copy number were measured by RT-qPCR. ATP levels were measured. Molecular docking between ISO and NRF1, and Co-IP assay for NRF1 and TFAM interaction were performed. Expression of NRF1 and TFAM was evaluated. ISO treatment reversed the detrimental effects of OGD/R on cell viability, attenuated the elevation of oxidative stress markers, restored antioxidant levels, and alleviated the impairment of mitochondrial biogenesis in SH-SY5Y cells. ISO interacted with NRF1 and increased its expression along with TFAM. Silencing NRF1 reversed the protective effects of ISO, suggesting its involvement in mediating the neuroprotective effects of ISO. ISO alleviates oxidative stress and mitochondrial biogenesis damage induced by OGD/R in SH-SY5Y cells by upregulating the NRF1/TFAM pathway.

Ginsenoside RD prevents acute liver injury in mice by inhibiting STAT3-mediated NLRP3/GSDMD activation

We investigated the role and mechanism of ginsenoside RD (GRD) in acute liver injury. Network pharmacology was used to analyze the correlations among GRD-liver injury-pyroptosis targets. A mouse model of acute liver injury was established by lipopolysaccharide + d-galactose（LPS + d/Gal). After pretreatment with GRD, the changes in mouse liver function were detected. The histopathological changes were assayed by hematoxylin and eosin and Masson staining, the tissue expressions of inflammatory cytokines were detected by enzyme-linked immunosorbent assay, and the protein expressions were assayed by immunohistochemical staining and Western blotting. Meanwhile, mechanism research was conducted using STAT3-knockout transgenic mice and STAT3-IN13, a STAT3 inhibitor. GRD inhibited liver injury, mitigated tissue inflammation, and suppressed STAT3-mediated pyroptosis in mice. After applying STAT3-knockout mouse model or STAT3-IN13, GRD did not further inhibit the liver injury. GRD can resist liver injury by inhibiting the STAT3-mediated pyroptosis, which is one of the hepatoprotective mechanisms of GRD.

Pharmacologic activation of activating transcription factor 6 contributes to neuronal survival after spinal cord injury in mice

The impact of primary and secondary injuries of spinal cord injury (SCI) results in the demise of numerous neurons, and there is still no efficacious pharmacological intervention for it. Recently, studies have shown that endoplasmic reticulum stress (ERS) plays a pivotal role in recovery of neurological function after spinal cord injury. As a process to cope with intracellular accumulation of misfolded and unfolded proteins which triggers ERS, the unfolded protein response (UPR) plays an important role in maintaining protein homeostasis. And, a recently disclosed small molecule AA147, which selectively activates activating transcription factor 6 (ATF6), has shown promising pharmacological effects in several disease models. Thus, it seems feasible to protect the neurons after spinal cord injury by modulating UPR. In this study, primary neurons were isolated from E17-19 C57BL/6J mouse embryos and we observed that AA147 effectively promoted the survival of neurons and alleviated neuronal apoptosis after oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. This was evident through a decrease in the proportion of PI-positive and TUNEL-positive cells, an increase in BCL-2 expression, and a decrease in the expression of BAX and C-caspase3. In in-vivo experiments, these findings were corroborated by TUNEL staining and immunohistochemistry. It was also found that AA147 enhanced three arms of the unfolded protein response with reduced CHOP expression. Besides, AA147 mitigated the accumulation of ROS in neurons probably by upregulating catalase expression. Furthermore, spinal cord injury models of C57BL/6J mice were established and behavioral experiments revealed that AA147 facilitated the recovery of motor function following SCI. Thus, pharmacologic activation of ATF6 represents a promise therapeutic approach to ameliorate the prognosis of SCI.

Research progress on the mechanism of action and clinical application of remote ischemic post-conditioning for acute ischemic stroke

Remote ischemic post-conditioning (RIPostC) can reduce cerebral ischemia reperfusion injury (IRI) by inducing endogenous protective effects, the distal limb ischemia post-treatment and in situ ischemia post-treatment were classified according to the site of intervention. And in the process of clinical application distal limb ischemia post-treatment is more widely used and more conducive to clinical translation. Therefore, in this paper, we review the mechanism of action and clinical application of RIPostC in cerebral ischemia, hoping to provide reference help for future experimental directions and clinical translation.

miR-3529-3p/ABCA1 axis regulates smooth muscle cell homeostasis by enhancing inflammation via JAK2/STAT3 pathway

Background

Thoracic Aortic Dissection (TAD) is a life-threatening disease without effective drug treatments. The disruption of HASMCs homeostasis is one direct histopathologic alteration in TAD pathological process. Several miRNAs have been shown abnormally expressed in TAD and to regulate HASMCs homeostasis. The primary goal of this study is to identify the miRNAs and the specific mechanisms that lead to HASMCs homeostasis disruption.

Methods

Bulk miRNA sequencing was performed to explore the aberrantly expressed miRNA profile in TAD, and differentially expressed miRNAs were verified with qRT-PCR. To explore the role of the key miRNAs (miR-3529) in HASMCs homeostasis, we overexpressed this miRNA with lentivirus in HASMCs. Integrative transcriptomics and metabolomics analysis were used to uncover the functional roles of this miRNA in regulating HASMCs homeostasis. Further, the target gene of miR-3529 was predicted by bioinformatics and verified through a dual-luciferase reporter assay.

Results

Bulk miRNA sequencing showed miR-3529 was elevated in TAD tissues and confirmed by qRT-PCR. Further experimental assay revealed miR-3529 upregulation induced HASMCs homeostasis disruption, accompanied by reducing contractile markers and increasing pro-inflammatory cytokines. Integrative transcriptomics and metabolomics analysis showed that miR-3529 overexpression altered the metabolic profile of HASMC, particularly lipid metabolism. ABCA1 was found to be a direct target of miR-3529. Mechanistically, the miR-3529/ABCA1 axis disrupted HASMCs homeostasis through the JAK2/STAT3 signaling pathway.

Conclusions

miR-3529 is elevated in TAD patients and disrupts HASMCs homeostasis by reprogramming metabolism through the JAK2/STAT3 signaling pathway. These findings favor a role for miR-3529 as a novel target for TAD therapy.

MCC950 as a promising candidate for blocking NLRP3 inflammasome activation: A review of preclinical research and future directions

The NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome is a key component of the innate immune system that triggers inflammation and pyroptosis and contributes to the development of several diseases. Therefore, blocking the activation of the NLRP3 inflammasome has therapeutic potential for the treatment of these diseases. MCC950, a selective small molecule inhibitor, has emerged as a promising candidate for blocking NLRP3 inflammasome activation. Ongoing research is focused on elucidating the specific targets of MCC950 as well as assessfing its metabolism and safety profile. This review discusses the diseases that have been studied in relation to MCC950, with a focus on stroke, Alzheimer's disease, liver injury, atherosclerosis, diabetes mellitus, and sepsis, using bibliometric analysis. It then summarizes the potential pharmacological targets of MCC950 and discusses its toxicity. Furthermore, it traces the progression from preclinical to clinical research for the treatment of these diseases. Overall, this review provides a solid foundation for the clinical therapeutic potential of MCC950 and offers insights for future research and therapeutic approaches.

Fisetin Promotes Functional Recovery after Spinal Cord Injury by Inhibiting Microglia/Macrophage M1 Polarization and JAK2/STAT3 Signaling Pathway

Spinal cord injury (SCI) is one of the most serious health problems, with no effective therapy. Recent studies indicate that Fisetin, a natural polyphenolic flavonoid, exhibits multiple functions, such as life-prolonging, antioxidant, antitumor, and neuroprotection. However, the restorative effects of Fisetin on SCI and the underlying mechanism are still unclear. In the present study, we found that Fisetin reduced LPS-induced apoptosis and oxidative damage in PC12 cells and reversed LPS-induced M1 polarization in BV2 cells. Additionally, Fisetin safely and effectively promoted the motor function recovery of SCI mice by attenuating neurological damage and promoting neurogenesis at the lesion. Moreover, Fisetin administration inhibited glial scar formation, modulated microglia/macrophage polarization, and reduced neuroinflammation. Network pharmacology, RNA-seq, and molecular biology revealed that Fisetin inhibited the activation of the JAK2/STAT3 signaling pathway. Notably, Colivelin TFA, an activator of JAK2/STAT3 signaling, attenuated Fis-mediated neuroinflammation inhibition and therapeutic effects on SCI mice. Collectively, Fisetin promotes functional recovery after SCI by inhibiting microglia/macrophage M1 polarization and the JAK2/STAT3 signaling pathway. Thus, Fisetin may be a promising therapeutic drug for the treatment of SCI.

Testis-Specific Protein, Y-Encoded-Like 2 Activates JAK2/STAT3 Pathway in Hypothalamic Paraventricular Nucleus to Sustain Hypertension

BACKGROUND

In the hypothalamic paraventricular nucleus (PVN) of spontaneously hypertensive rats (SHRs), the expression of the testis-specific protein, Y-encoded-like 2 (TSPYL2) and the phosphorylation level of Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) are higher comparing with the normotensive Wistar Kyoto rats (WKY). But how they are involved in hypertension remains unclear. TSPYL2 may interact with JAK2/STAT3 in PVN to sustain high blood pressure during hypertension.

METHODS

Knockdown of TSPYL2 via adeno-associated virus (AAV) carrying shRNA was conducted through bilateral microinjection into the PVN of SHR and WKY rats. JAK2/STAT3 inhibition was achieved by intraperitoneally or PVN injection of AG490 into the SHRs. Blood pressure (BP), plasma norepinephrine (NE), PVN inflammatory response, and PVN oxidative stress were measured.

RESULTS

TSPYL2 knock-down in the PVN of SHRs but not WKYs led to reduced BP and plasma NE, deactivation of JAK2/STAT3, decreased expression of pro-inflammatory cytokine IL-1β, and increased expression of anti-inflammatory cytokine IL-10 in the PVN. Meanwhile, AG490 administrated in both ways reduced the BP in the SHRs and deactivated JAK2/STAT3 but failed to change the expression of TSPYL2 in PVN. AG490 also downregulated expression of IL-1β and upregulated expression of IL-10. Both knockdown of TSPYL2 and inhibition of JAK2/STAT3 can reduce the oxidative stress in the PVN of SHRs.

CONCLUSION

JAK2/STAT3 is regulated by TSPYL2 in the PVN of SHRs, and PVN TSPYL2/JAK2/STAT3 is essential for maintaining high BP in hypertensive rats, making it a potential therapeutic target for hypertension.

Blueberry extract for the treatment of ischaemic stroke through regulating the gut microbiota and kynurenine metabolism

Although the gut microbiota and kynurenine (KYN) metabolism have significant protective effects against ischaemic stroke (IS), the exact mechanism has yet to be fully elucidated. Combined serum metabolomics and 16S rRNA gene sequencing were used to reveal the differences between the gut microbiota and metabolites in rats treated with or without blueberry extract. Faecal microbiota transplantation (FMT) was employed to validate the protective role of the gut microbiota in IS. Furthermore, the interaction between Prevotella and IS was also confirmed in patients. Rats with IS experienced neurological impairments accompanied by an impaired intestinal barrier and disturbed intestinal flora, which further contributed to heightened inflammatory responses. Furthermore, Prevotella played a critical role in IS pathophysiology, and a positive correlation between Prevotella and KYN was detected. The role of KYN metabolism in IS was further demonstrated by the finding that IDO was significantly upregulated and that the use of the IDO inhibitor, attenuated KYN metabolic pathway activity and ameliorated neurological damage in rats with IS. Prevotella intervention also significantly improved stroke symptoms and decreasing KYN levels in rats with IS. FMT showed that the beneficial effects of blueberry extract on IS involve gut bacteria, especially Prevotella, which were confirmed by microbiological analyses conducted on IS patients. Moreover, blueberry extract led to significant changes in kynurenic acid levels and tryptophan and IDO levels through interactions with Prevotella. Our study demonstrates for the first time that blueberry extract could modulate "intestinal microecology-KYN metabolism" to improve IS.

Vascular Aging in Ischemic Stroke

Cellular senescence, a permanent halt in cell division due to stress, spurs functional and structural changes, contributing to vascular aging characterized by endothelial dysfunction and vascular remodeling. This process raises the risk of ischemic stroke (IS) in older individuals, with its mechanisms still not completely understood despite ongoing research efforts. In this review, we have analyzed the impact of vascular aging on increasing susceptibility and exacerbating the pathology of IS. We have emphasized the detrimental effects of endothelial dysfunction and vascular remodeling influenced by oxidative stress and inflammatory response on vascular aging and IS. Our goal is to aid the understanding of vascular aging and IS pathogenesis, particularly benefiting older adults with high risk of IS.

Effect of IL-9 neutralising antibody on pyroptosis via SGK1/NF-κB/NLRP3/GSDMD in allergic rhinitis mice

Allergic rhinitis is a common non-infectious inflammatory disease that affects approximately 15 % of people worldwide and has a complex and unclear aetiology. In recent years, pyroptosis has been found to play a role in the development of allergic rhinitis. IL-9, pyroptosis, serum and glucocorticoid-induced protein kinase 1 (SGK1), NOD-like receptor 3 (NLRP3), and nuclear factor kappa B (NF-κB) have been shown to influence each other. Herein, we aimed to explore the role of IL-9 neutralising antibody in pyroptosis involving IL-9, SGK1, NF-κB, and NLRP3 in allergic rhinitis. We observed a decrease in cytokines involved in pyroptosis and gasdermin D (GSDMD) compared with those in mice with allergic rhinitis. Further, phosphorylation of NF-κB/p65 decreased compared with that in mice with allergic rhinitis; NLRP3 and ASC also decreased, although the levels were higher than those in controls. SGK1 levels decreased compared with that in mice with allergic rhinitis and increased after using IL-9 neutralising antibodies, thus demonstrating its negative regulatory effects. The IL-9 neutralising antibody reduced the inflammatory and pyroptosis responses via SGK1 and NF-κB/NLRP3/GSDMD pathway. Our research results indicate that IL-9 regulates allergic rhinitis via the influence of SGK1 and NF-κB/NLRP3/GSDMD signalling pathway, providing new insights for developing novel drugs to treat allergic rhinitis.

Huanglian Jiedu decoction alleviates ischemia-induced cerebral injury in rats by mitigating NET formation and activiting GABAergic synapses

Huanglian Jiedu decoction (HLJD) has been used to treat ischemic stroke in clinic. However, the detailed protective mechanisms of HLJD on ischemic stroke have yet to be elucidated. The aim of this study is to elucidate the underlying pharmacological mechanisms of HLJD based on the inhibition of neuroinflammation and the amelioration of nerve cell damage. A middle cerebral artery occlusion reperfusion (MCAO/R) model was established in rats and received HLJD treatment. Effects of HLJD on neurological function was assessed based on Bederson's score, postural reflex test and asymmetry score. 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining, Hematein and eosin (HE) and Nissl staining were used to observe the pathological changes in brain. Then, transcriptomics was used to screen the differential genes in brain tissue in MCAO/R model rats following HLJD intervention. Subsequently, the effects of HLJD on neutrophil extracellular trap (NET) formation-related neuroinflammation, gamma-aminobutyric acid (GABA)ergic synapse activation, nerve cell damage and proliferation were validated using immunofluorescence, western blot and enzyme-linked immunosorbent assay (ELISA). Our results showed that HLJD intervention reduced the Bederson's score, postural reflex test score and asymmetry score in MCAO/R model rats. Pathological staining indicated that HLJD treatment decreased the cerebral infarction area, mitigated neuronal damage and increased the numbers of Nissl bodies. Transcriptomics suggested that HLJD affected 435 genes in MCAO/R rats. Among them, several genes involving in NET formation and GABAergic synapses pathways were dysregulated. Subsequent experimental validation showed that HLJD reduced the MPO+CitH3+ positive expression area, reduced the protein expression of PAD4, p-P38/P38, p-ERK/ERK and decreased the levels of IL-1β, IL-6 and TNF-α, reversed the increase of Iba1+TLR4+, Iba1+p65+ and Iba1+NLRP3+ positive expression area in brain. Moreover, HLJD increased GABA levels, elevated the protein expression of GABRG1 and GAT3, decreased the TUNEL positive expression area and increased the Ki67 positive expression area in brain. HLJD intervention exerts a multifaceted positive impact on ischemia-induced cerebral injury in MCAO/R rats. This intervention effectively inhibits neuroinflammation by mitigating NET formation, and concurrently improves nerve cell damage and fosters nerve cell proliferation through activating GABAergic synapses.

Elabela ameliorates neuronal pyroptosis and mitochondrial fission via APJ/ZBP1 signaling in ischemic stroke

Pyroptosis signifies a significant form of programmed neuronal demise subsequent to ischemic stroke. In our prior investigations, we demonstrated that the Elabela (ELA)-Apelin receptor (APJ) axis alleviated neuronal death by improving collateral circulation and mitigating ferroptosis in a murine model of middle cerebral artery occlusion (MCAO). However, the connection between ELA and neuronal pyroptosis remains further elucidation. Here, we observed an upregulation of ELA and APJ expression in both murine brain specimens and cultured HT-22 hippocampal neurons exposed to experimental ischemic stroke. ELA administration markedly diminished the infarct size in comparison to controls. ELA treatment ameliorated neurological deficits and anxiety-like symptoms in mice with stroke, concurrently inhibiting pyroptosis and mitochondria fission in neurons. Conversely, ELA knockdown yielded the opposite effects. Utilizing RNA-sequencing analysis, we identified a candidate for pyroptosis priming, Z-DNA-binding protein 1 (ZBP1), which was suppressed in ELA-treated HT-22 neurons during oxygen-glucose deprivation/reperfusion (OGD/R). Subsequent co-immunoprecipitation analyses demonstrated the binding between APJ and ZBP1. Specifically, APJ suppressed ZBP1 to inhibit NLRP3 inflammasome activation and dynamin-related protein 1-mediated mitochondrial fission in neurons. In summary, our findings suggest that ELA functions as a stroke-induced signal limiting neuronal pyroptosis and mitochondrial fission via APJ/ZBP1 signaling, thereby underscoring ELA as a potential therapeutic target for ischemic stroke treatment.

Targeting NLRP3 Inflammasomes: A Trojan Horse Strategy for Intervention in Neurological Disorders

Recently, a growing focus has been on identifying critical mechanisms in neurological diseases that trigger a cascade of events, making it easier to target them effectively. One such mechanism is the inflammasome, an essential component of the immune response system that plays a crucial role in disease progression. The NLRP3 (nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3) inflammasome is a subcellular multiprotein complex that is widely expressed in the central nervous system (CNS) and can be activated by a variety of external and internal stimuli. When activated, the NLRP3 inflammasome triggers the production of proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) and facilitates rapid cell death by assembling the inflammasome. These cytokines initiate inflammatory responses through various downstream signaling pathways, leading to damage to neurons. Therefore, the NLRP3 inflammasome is considered a significant contributor to the development of neuroinflammation. To counter the damage caused by NLRP3 inflammasome activation, researchers have investigated various interventions such as small molecules, antibodies, and cellular and gene therapy to regulate inflammasome activity. For instance, recent studies indicate that substances like micro-RNAs (e.g., miR-29c and mR-190) and drugs such as melatonin can reduce neuronal damage and suppress neuroinflammation through NLRP3. Furthermore, the transplantation of bone marrow mesenchymal stem cells resulted in a significant reduction in the levels of pyroptosis-related proteins NLRP3, caspase-1, IL-1β, and IL-18. However, it would benefit future research to have an in-depth review of the pharmacological and biological interventions targeting inflammasome activity. Therefore, our review of current evidence demonstrates that targeting NLRP3 inflammasomes could be a pivotal approach for intervention in neurological disorders.

Long-Term Alcohol Exposure Aggravates Ischemic Stroke-Induced Damage by Promoting Pericyte NLRP3 Inflammasome Activation via Pre-Activating the TLR4/NF-κB Pathway in Rats

Background

Ischemic stroke (IS) is one of the leading causes of death and disability in the world, and alcohol consumption has been gaining attention as an independent risk factor for IS. Blood-brain barrier (BBB) dysfunction and neuroinflammation are the core of cerebral ischemia/reperfusion (I/R) injury, and pericytes play a crucial role in the structure and function. This study is to explore the effects of long-term alcohol consumption on IS and the potential mechanisms of pericytes.

Methods

Rat models of long-term alcohol intake followed by transient middle cerebral artery occlusion stroke (EtOH+tMCAO) and cell models of oxygen-glucose deprivation/reoxygenation (OGD/R) with alcohol pre-treatment were constructed.

Results

Worsened infarct volume, neurological scores, and BBB disruption were observed in the EtOH+tMCAO group compared with the tMCAO group, and immunofluorescence staining showed increased pericytes NLPR3 inflammasome activation at the ischemic penumbra. In vitro, pericyte mortality and LDH release elevated pre-treated by alcohol after OGD/R, and amplified expression of NLRP3 inflammasome was detected by Western blotting and qPCR. Alcohol pre-treatment activated the TLR4/NF-κB pathway, and transfecting pericytes with TLR4-small interfering RNA (siRNA) to block TLR4 signaling markedly restrained NLRP3 inflammasome over-activation. Injecting TAK-242 in rats alleviated neurological impairment caused by alcohol.

Conclusion

Long-term alcohol pre-treatment aggravated ischemic stroke-induced brain damage by activating NLRP3 inflammasome via TLR4/NF-κB signaling pathway in the pericytes.

Ghrelin/GHSR System in Depressive Disorder: Pathologic Roles and Therapeutic Implications

Depression is the most common chronic mental illness and is characterized by low mood, insomnia, and affective disorders. However, its pathologic mechanisms remain unclear. Numerous studies have suggested that the ghrelin/GHSR system may be involved in the pathophysiologic process of depression. Ghrelin plays a dual role in experimental animals, increasing depressed behavior and decreasing anxiety. By combining several neuropeptides and traditional neurotransmitter systems to construct neural networks, this hormone modifies signals connected to depression. The present review focuses on the role of ghrelin in neuritogenesis, astrocyte protection, inflammatory factor production, and endocrine disruption in depression. Furthermore, ghrelin/GHSR can activate multiple signaling pathways, including cAMP/CREB/BDNF, PI3K/Akt, Jak2/STAT3, and p38-MAPK, to produce antidepressant effects, given which it is expected to become a potential therapeutic target for the treatment of depression.

A novel p55PIK signaling peptide inhibitor alleviates neuroinflammation via the STAT3/NF-kB signaling pathway in experimental stroke

BACKGROUND

Ischemic stroke remains the predominant contributor to mortality and disability globally. Microglia undergo rapid activation and initiate inflammatory cascade reactions by phenotypic polarization, participating in the regulation of inflammatory injury and tissue repair post-ischemic stroke. Regulating microglia-mediated neuroinflammation is a promising therapeutic strategy for ischemic stroke. Previously, we designed and synthesized a novel p55PIK inhibitor, TAT-N15 polypeptide, which presents inhibitive activity on NF-κB signaling-mediated inflammation in acute conjunctivitis and allergic rhinitis. The present study aimed to explore the therapeutic effect and mechanism of TAT-N15 on ischemia stroke.

METHODS

The mouse model of transient cerebral ischemia was made using the intraluminal filament method. After being treated with daily intraperitoneal injections of TAT-N15 (10 mg/kg) for 7 d, the neurological outcomes and the cerebral infarction volume were evaluated. Histopathology of the ischemia cerebral hemisphere was observed by H&E and Nissl staining. Neuronal survival, astrogliosis, and co-labeling of CD86/Iba1 and CD206/Iba1 were detected by immunofluorescence. The cell apoptosis was estimated by TUNEL staining. The expression levels of apoptosis-associated proteins, proinflammatory cytokines, protein markers of M1 and M2 microglia, and the phosphorylation of NF-κB and STAT3 proteins in the ischemic penumbra were detected by Western blot.

RESULTS

TAT-N15 treatment significantly decreased the infarct volume and alleviated neurological functional impairment, neuronal injury, and neuron apoptosis. Meanwhile, TAT-N15 treatment restrained the activation of microglia and astrocytes as well as the protein expression of proinflammatory cytokine in ischemic penumbra. Additionally, the administration of TAT-N15 treatment resulted in a significant reduction in the density of M1 phenotype microglia while concurrently increasing the density of M2 phenotype microglia within the ischemic penumbra. Finally, mechanical analysis unveiled that TAT-N15 exerted a substantial inhibitory effect on the protein expression of phosphorylated STAT3 and NF-κB.

CONCLUSION

TAT-N15 may inhibit neuroinflammation via regulating microglia activation and polarization through the STAT3/NF-κB pathway, which exhibits the neuroprotection effect in ischemic stroke.

Combining metabolomics and network pharmacology to investigate the protective effect of Jiawei Xinglou Chengqi Granules in ischemic stroke

Jiawei Xinglou Chengqi Granule (JXCG) is an effective herbal medicine for the treatment of ischemic stroke (IS). JXCG has been shown to effectively ameliorate cerebral ischemic symptoms in clinical practice, but the underlying mechanisms are unclear. In this study, we investigated the mechanisms of action of JXCG in the treatment of IS by combining metabolomics with network pharmacology. The chemical composition of JXCG was analyzed using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Ultra-high performance liquid chromatography-tandem time-of-flight mass spectrometry (UHPLC-Q-TOF MS) untargeted metabolomics were used to identify differential metabolites within metabolic pathways. Network pharmacology was applied to mine potential targets of JXCG in the treatment of IS. The identified key targets were validated by constructing an integrated network of metabolomics and network pharmacology and by molecular docking using Cytoscape. The effect of JXCG on IS was evaluated in vivo, and the predicted targets and pathways of JXCG in IS therapy were assessed using immunoblotting. Combining metabolomics and network pharmacology, we identified the therapeutic targets of JXCG for IS. Notably, JXCG lessened neuronal damage and reduced cerebral infarct size in rats with IS. Western blot analysis showed that JXCG upregulated PRKCH and downregulated PRKCE and PRKCQ proteins. Our combined network pharmacology and metabolomics findings showed that JXCG may have therapeutic potential in the treatment of IS by targeting multiple factors and pathways.

FOXP3 gene is associated with susceptibility to ischemic stroke in the Chinese population

AIM

Immunoinflammatory response plays an important role in the pathophysiological process of ischemic stroke (IS). Forkhead box P3 (FOXP3) is a master regulator for immune cells. Polymorphisms of FOXP3 gene might contribute to the susceptibility of IS. This study aimed to explore the association between FOXP3 gene polymorphisms (rs3761548 and rs2232365) and IS susceptibility in the Chinese Han population.

METHODS

Polymerase chain reaction and Sanger sequencing were used to detect the genotype of FOXP3 gene rs3761548 and rs2232365 polymorphisms.

RESULTS

Smoking, diabetes mellitus (DM), and HBP histories, higher TG and HDL-C levels were more frequently observed in IS patients than in controls. In comparison with rs3761548 GG genotype, GT genotype (OR = 1.573, 95 %CI = 1.030-2.402; adjusted: OR = 1.736, 95 %CI = 1.070-2.817) and GT + TT vs. GG model (OR = 1.581, 95 %CI = 1.0449-2.382; adjusted: OR = 1.720, 95 %CI = 1.074-2.755) of rs3761548 polymorphism was significantly correlated with elevated ischemic stroke susceptibility both at prior and after adjusted by smoking, HBP, DM, TG and HDL-C. Recessive model of rs2232365 polymorphism could elevate the susceptibility of ischemic stroke (OR = 11.962, 95 %CI = 1.144-3.3363; adjusted: OR = 1.876, 95 %CI = 1.016-3.463). Besides, rs3761548 dominant model (OR = 2.757, 95 %CI = 1.379-5.552; adjusted: OR = 2.601, 95 %CI = 1.268-5.336) and rs2232365 recessive model (OR = 3.103, 95 %CI = 1.463-6.583; adjusted: OR = 3.545, 95 %CI = 1.600-7.855) were related to the severity of ischemic stroke.

CONCLUSION

FOXP3 gene rs3761548 and rs2232365 polymorphisms were risk factors for susceptibility and severity of IS.

[2, 6-dimethoxy-1, 4-benzoquinone alleviates septic shock in mice by inhibiting NLRP3 inflammasome activation]

OBJECTIVE

To investigate the mechanism of 2, 6-dimethoxy-1, 4-benzoquinone (DMQ), an active ingredients in fermented wheat germ extract, for inhibiting NLRP3 inflammasome activation and alleviating septic shock in mice.

METHODS

Cultured murine bone marrow-derived macrophages (BMDM) stimulated with lipopolysaccharide (LPS) were treated with DMQ, followed by treatment with Nigericin, ATP, and MSU for activating the canonical NLRP3 inflammasome; the noncanonical NLRP3 inflammasome was activated by intracellular transfection of LPS, and AIM2 inflammasome was activated using Poly A: T.In human monocytic THP-1 cells, the effect of Nigericin on inflammasome activation products was examined using Western blotting and ELISA.Co-immunoprecipitation was performed to explore the mechanism of DMQ-induced blocking of NLRP3 inflammasome activation.In a male C57BL/6J mouse model of LPS-induced septic shock treated with 20 and 40 mg/kg DMQ, the levels of IL-1β and TNF-α in the serum and peritoneal lavage fluid were determined using ELISA, and the survival time of the mice within 36 h was observed.

RESULTS

Treatment with DMQ effectively inhibited LPS-induced activation of canonical NLRP3 inflammasome in mouse BMDM and human THP-1 cells and also inhibited non-canonical NLRP3 inflammasome activation in mouse BMDM, but produced no significant effect on AIM2 inflammasome activation.DMQ significantly blocked the binding between ASC and NLRP3.In the mouse models of septic shock, DMQ treatment significantly reduced the levels of IL-1β in the serum and peritoneal fluid and obviously prolonged survival time of the mice.

CONCLUSION

DMQ can effectively block ASC-NLRP3 interaction to inhibit NLRP3 inflammasome activation and alleviate LPSinduced septic shock in mice.

Network analysis of microbiome and metabolome to explore the mechanism of raw rhubarb in the protection against ischemic stroke via microbiota-gut-brain axis

Ischemic stroke (IS) has attracted worldwide attention due to the high mortality and disability rate. Raw rhubarb (RR) is a traditional medicinal plant and whole-food that has been used in China for its various pharmacological activities, such as antioxidant and anti-inflammatory properties. Recent pharmacological research has shown the role of RR against IS, but its mechanism of action remains unclear, particularly in the context of the brain-gut axis. To address this gap in knowledge, the present study was conducted in the middle cerebral artery occlusion/reperfusion (MCAO/R) model with the aim of investigating the effects of RR on regulating the intestinal microbiota barrier and metabolism and thereby reducing inflammatory response so as to improve the IS. The results showed that pre-treatment of RR attenuated cerebral infarct area and inflammation response in MCAO rats. Furthermore, RR also improved intestinal barrier function, including the integrity and permeability of the intestinal barrier. Additionally, RR intervention significantly attenuated gut microbiota dysbiosis caused by ischemic stroke, especially the increased Firmicutes. Notably, the pseudo-germ-free (PGF) rats further demonstrated that the anti-stroke effect of RR might rely on intestinal microbiota. In addition, the UPLC/Q-Orbitrap-MS-Based metabolomics revealed the disrupted metabolic profiles caused by MCAO/R, and a total of 11 differential metabolites were modulated by RR administration, especially bile acids. Further correlation analysis and network pharmacology analysis also demonstrated a strong association between specific bacteria, such as Firmicutes and bile acids. In conclusion, our work demonstrated that RR could effectively ameliorate ischemic stroke by modulating the microbiota and metabolic disorders.

Reynosin protects neuronal cells from microglial neuroinflammation by suppressing NLRP3 inflammasome activation mediated by NADPH oxidase

Neuroinflammation, mediated by the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing-3 (NLRP3) inflammasome, is a significant contributor to the pathogenesis of neurodegenerative diseases (NDDs). Reynosin, a natural sesquiterpene lactone (SL), exhibits a broad spectrum of pharmacological effects, suggesting its potential therapeutic value. However, the effects and mechanism of reynosin on neuroinflammation remain elusive. The current study explores the effects and mechanisms of reynosin on neuroinflammation using mice and BV-2 microglial cells treated with lipopolysaccharide (LPS). Our findings reveal that reynosin effectively reduces microglial inflammation in vitro, as demonstrated by decreased CD11b expression and lowered interleukin-1 beta (IL-1β) and interleukin-18 (IL-18) mRNA and protein levels. Correspondingly, in vivo, results showed a reduction in the number of Iba-1 positive cells and alleviation of morphological alterations, alongside decreased expressions of IL-1β and IL-18. Further analysis indicates that reynosin inhibits NLRP3 inflammasome activation, evidenced by reduced transcription of NLRP3 and caspase-1, diminished NLRP3 protein expression, inhibited apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization, and decreased caspase-1 self-cleavage. Additionally, reynosin curtailed the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, demonstrated by reduced NADP+ and NADPH levels, downregulation of gp91phox mRNA, protein expression, suppression of p47phox expression and translocation to the membrane. Moreover, reynosin exhibited a neuroprotective effect against microglial inflammation in vivo and in vitro. These collective findings underscore reynosin's capacity to mitigate microglial inflammation by inhibiting the NLRP3 inflammasome, thus highlighting its potential as a therapeutic agent for managing neuroinflammation.

Icariin inhibits apoptosis in OGD-induced neurons by regulating M2 pyruvate kinase

Background

Ischaemic stroke can lead to many complications, but treatment options are limited. Icariin is a traditional Chinese medicine with reported neuroprotective effects against ischaemic cerebral injury; however, the underlying mechanisms by which icariin ameliorates cell apoptosis require further study.

Purpose

This study aimed to investigate the therapeutic potential of icariin after ischaemic stroke and the underlying molecular mechanisms.

Methods

N2a neuronal cells were used to create an in vitro oxygen-glucose deprivation (OGD) model. The effects of icariin on OGD cells were assessed using the CCK-8 kit to detect the survival of cells and based on the concentration, apoptosis markers, inflammation markers, and M2 pyruvate kinase isoenzyme (PKM2) expression were detected using western blotting, RT-qPCR, and flow cytometry. To investigate the underlying molecular mechanisms, we used the PKM2 agonist TEPP-46 and detected apoptosis-related proteins.

Results

We demonstrated that icariin alleviated OGD-induced apoptosis in vitro. The expression levels of the apoptosis marker proteins caspase-3 and Bax were upregulated and Bcl-2 was downregulated. Furthermore, icariin reduced inflammation and downregulated the expression of PKM2. Moreover, activation of the PKM2 by pretreatment with the PKM2 agonist TEPP-46 enhanced the effects on OGD induced cell apoptosis in vitro.

Conclusion

This study elucidated the underlying mechanism of PKM2 in OGD-induced cell apoptosis and highlighted the potential of icariin in the treatment of ischaemic stroke.

Effect of Oxygen-Glucose Deprivation of Microglia-Derived Exosomes on Hippocampal Neurons: A Study on miR-124 and Inflammatory Cytokines

Stroke is a cerebrovascular disease that threatens human health. Developing safe and effective drugs and finding therapeutic targets has become an urgent scientific problem. The aim of this study was to investigate the effect of oxygen-glucose deprivation of the microglia-derived exosome on hippocampal neurons and its relationship to miR-124 in the exosome. We incubated hippocampal neurons with exosomes secreted by oxygen-glucose deprivation/ reoxygenation (OGD/R) microglia. The levels of glutamic acid (GLU) and gamma-aminobutyric acid (GABA) in the culture supernatant were detected by ELISA. CCK-8 was used to measure neuronal survival rates. The mRNA levels of TNF-α and IL-6 were detected by RT-qPCR to evaluate the effect of exosomes on neurons. RT-qPCR was then used to detect miR-124 in microglia and their secreted exosomes. Finally, potential targets of miR-124 were analyzed through database retrieval, gene detection with dual luciferase reporters, and western blotting experiments. The results showed that the contents of GLU, TNF-α and IL-6 mRNA increased in the supernatant of cultured hippocampal neurons, the content of GABA decreased, and the survival rate of neurons decreased. Oxygen-glucose deprivation increases miR-124 levels in microglia and their released exosomes. miR-124 acts as a target gene on cytokine signaling suppressor molecule 1(SOCS1), while miR-124 inhibitors reduce the expression of TNF-α and IL-6 mRNA in neurons. These results suggest that oxygen- and glucose-deprived microglia regulate inflammatory cytokines leading to reduced neuronal survival, which may be achieved by miR-124 using SOCS1 as a potential target.

Targeting pyroptosis to treat ischemic stroke: From molecular pathways to treatment strategy

Ischemic stroke is the primary reason for human disability and death, but the available treatment options are limited. Hence, it is imperative to explore novel and efficient therapies. In recent years, pyroptosis (a pro-inflammatory cell death characterized by inflammation) has emerged as an important pathological mechanism in ischemic stroke that can cause cell death through plasma membrane rupture and release of inflammatory cytokines. Pyroptosis is closely associated with inflammation, which exacerbates the inflammatory response in ischemic stroke. The level of inflammasomes, GSDMD, Caspases, and inflammatory factors is increased after ischemic stroke, exacerbating brain injury by mediating pyroptosis. Hence, inhibition of pyroptosis can be a therapeutic strategy for ischemic stroke. In this review, we have summarized the relationship between pyroptosis and ischemic stroke, as well as a series of treatments to attenuate pyroptosis, intending to provide insights for new therapeutic targets on ischemic stroke.

Activation of Inflammasomes and Relevant Modulators for the Treatment of Microglia-mediated Neuroinflammation in Ischemic Stroke

As the brain's resident immune patrol, microglia mediate endogenous immune responses to central nervous system injury in ischemic stroke, thereby eliciting either neuroprotective or neurotoxic effects. The association of microglia-mediated neuroinflammation with the progression of ischemic stroke is evident through diverse signaling pathways, notably involving inflammasomes. Within microglia, inflammasomes play a pivotal role in promoting the maturation of interleukin-1β (IL-1β) and interleukin-18 (IL-18), facilitating pyroptosis, and triggering immune infiltration, ultimately leading to neuronal cell dysfunction. Addressing the persistent and widespread inflammation holds promise as a breakthrough in enhancing the treatment of ischemic stroke.

Trigeminal nerve electrical stimulation attenuates early traumatic brain injury through the TLR4/NF-κB/NLRP3 signaling pathway mediated by orexin-A/OX1R system

BACKGROUND

Traumatic brain injury (TBI) is a significant contributor to global mortality and disability, and emerging evidence indicates that trigeminal nerve electrical stimulation (TNS) is a promising therapeutic intervention for neurological impairment following TBI. However, the precise mechanisms underlying the neuroprotective effects of TNS in TBI are poorly understood. Thus, the objective of this study was to investigate the potential involvement of the orexin-A (OX-A)/orexin receptor 1 (OX1R) mediated TLR4/NF-κB/NLRP3 signaling pathway in the neuroprotective effects of TNS in rats with TBI.

METHODS

Sprague-Dawley rats were randomly assigned to four groups: sham, TBI, TBI+TNS+SB334867, and TBI+TNS. TBI was induced using a modified Feeney's method, and subsequent behavioral assessments were conducted to evaluate neurological function. The trigeminal nerve trunk was isolated, and TNS was administered following the establishment of the TBI model. The levels of neuroinflammation, brain tissue damage, and proteins associated with the OX1R/TLR4/NF-κB/NLRP3 signaling pathway were assessed using hematoxylin-eosin staining, Nissl staining, western blot analysis, quantitative real-time polymerase chain reaction, and immunofluorescence techniques.

RESULTS

The findings of our study indicate that TNS effectively mitigated tissue damage, reduced brain edema, and alleviated neurological deficits in rats with TBI. Furthermore, TNS demonstrated the ability to attenuate neuroinflammation levels and inhibit the expression of proteins associated with the TLR4/NF-κB/NLRP3 signaling pathway. However, it is important to note that the aforementioned effects of TNS were reversible upon intracerebroventricular injection of an OX1R antagonist.

CONCLUSION

TNS may prevent brain damage and relieve neurological deficits after a TBI by inhibiting inflammation, possibly via the TLR4/NF-κB/NLRP3 signaling pathway mediated by OX-A/OX1R.

Inhibition of STAT3 by S3I-201 suppress peritoneal fibroblast phenotype conversion and alleviate peritoneal fibrosis

Peritoneal fibrosis is a common pathological response to long-term peritoneal dialysis (PD) and a major cause for PD discontinuation. Understanding the cellular and molecular mechanisms underlying the induction and progression of peritoneal fibrosis is of great interest. In our study, in vitro study revealed that signal transducer and activator of transcription 3 (STAT3) is a key factor in fibroblast activation and extracellular matrix (ECM) synthesis. Furthermore, STAT3 induced by IL-6 trans-signalling pathway mediate the fibroblasts of the peritoneal stroma contributed to peritoneal fibrosis. Inhibition of STAT3 exerts an antifibrotic effect by attenuating fibroblast activation and ECM production with an in vitro co-culture model. Moreover, STAT3 plays an important role in the peritoneal fibrosis in an animal model of peritoneal fibrosis developed in mice. Blocking STAT3 can reduce the peritoneal morphological changes induced by chlorhexidine gluconate. In conclusion, our findings suggested STAT3 signalling played an important role in peritoneal fibrosis. Therefore, blocking STAT3 might become a potential treatment strategy in peritoneal fibrosis.

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

MG53/GMs/HA-Dex neural scaffold promotes the functional recovery of spinal cord injury by alleviating neuroinflammation

The adverse microenvironment, including neuroinflammation, hinders the recovery of spinal cord injury (SCI). Regulating microglial polarization to alleviate neuroinflammation at the injury site is an effective strategy for SCI recovery. MG53 protein exerts obvious repair ability on multiple tissues damage, but with short half-life. In this study, we composited an innovative MG53/GMs/HA-Dex neural scaffold using gelatin microspheres (GMs), hyaluronic acid (HA), and dextran (Dex) loaded with MG53 protein. This novel neural scaffold could respond to MMP-2/9 protein and stably release MG53 protein with good physicochemical properties and biocompatibility. In addition, it significantly improved the motor function of SCI mice, suppressed M1 polarization of microglia and neuroinflammation, and promoted neurogenesis and axon regeneration. Further mechanistic experiments demonstrated that MG53/GMs/HA-Dex hydrogel inhibited the JAK2/STAT3 signaling pathway. Thus, this MG53/GMs/HA-Dex neural scaffold promotes the functional recovery of SCI mice by alleviating neuroinflammation, which provides a new intervention strategy for the neural regeneration and functional repair of SCI.

Dysregulated SYVN1 promotes CAV1 protein ubiquitination and accentuates ischemic stroke

BACKGROUND

Stroke is a major cause of death and severe disability, and there remains a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke (IS) to protect the brain against damage before and during recanalization. Caveolin-1 (CAV1), an integrated protein that is located at the caveolar membrane, has been reported to exert neuroprotective effects during IS. Nevertheless, the mechanism remains largely unknown. Here, we explored the upstream modifiers of CAV1 in IS.

METHODS

E3 ubiquitin ligases of CAV1 that are differentially expressed in IS were screened using multiple databases. The transcription factor responsible for the dysregulation of E3 ubiquitin-protein ligase synoviolin (SYVN1) in IS was predicted and verified. Genetic manipulations by lentiviral vectors were applied to investigate the effects of double-strand-break repair protein rad21 homolog (RAD21), SYVN1, and CAV1 in a middle cerebral artery occlusion (MCAO) mouse model and mouse HT22 hippocampal neurons induced by oxygen-glucose deprivation (OGD).

RESULTS

SYVN1 was highly expressed in mice with MCAO, and knockdown of SYVN1 alleviated IS injury in mice, as evidenced by limited infarction volume, the lower water content in the brain, and repressed apoptosis and inflammatory response. RAD21 inhibited the transcription of SYVN1, thereby reducing the ubiquitination modification of CAV1. Overexpression of RAD21 elicited a neuroprotective role as well in mice with MCAO and HT22 induced with OGD, which was overturned by SYVN1.

CONCLUSION

Transcriptional repression of SYVN1 by RAD21 alleviates IS in mice by reducing ubiquitination modification of CAV1.

Integrating Bulk RNA and Single-Cell Sequencing Data Unveils Efferocytosis Patterns and ceRNA Network in Ischemic Stroke

Excessive inflammatory response following ischemic stroke (IS) injury is a key factor affecting the functional recovery of patients. The efferocytic clearance of apoptotic cells within ischemic brain tissue is a critical mechanism for mitigating inflammation, presenting a promising avenue for the treatment of ischemic stroke. However, the cellular and molecular mechanisms underlying efferocytosis in the brain after IS and its impact on brain injury and recovery are poorly understood. This study explored the roles of inflammation and efferocytosis in IS with bioinformatics. Three Gene Expression Omnibus Series (GSE) (GSE137482-3 m, GSE137482-18 m, and GSE30655) were obtained from NCBI (National Center for Biotechnology Information) and GEO (Gene Expression Omnibus). Differentially expressed genes (DEGs) were processed for GSEA (Gene Set Enrichment Analysis), GO (Gene Ontology Functional Enrichment Analysis), and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses. Efferocytosis-related genes were identified from the existing literature, following which the relationship between Differentially Expressed Genes (DEGs) and efferocytosis-related genes was examined. The single-cell dataset GSE174574 was employed to investigate the distinct expression profiles of efferocytosis-related genes. The identified hub genes were verified using the dataset of human brain and peripheral blood sample datasets GSE56267 and GSE122709. The dataset GSE215212 was used to predict competing endogenous RNA (ceRNA) network, and GSE231431 was applied to verify the expression of differential miRNAs. At last, the middle cerebral artery (MCAO) model was established to validate the efferocytosis process and the expression of hub genes. DEGs in two datasets were significantly enriched in pathways involved in inflammatory response and immunoregulation. Based on the least absolute shrinkage and selection operator (LASSO) analyses, we identified hub efferocytosis-related genes (Abca1, C1qc, Ptx3, Irf5, and Pros1) and key transcription factors (Stat5). The scRNA-seq analysis showed that these hub genes were mainly expressed in microglia and macrophages which are the main cells with efferocytosis function in the brain. We then identified miR-125b-5p as a therapeutic target of IS based on the ceRNA network. Finally, we validated the phagocytosis and clearance of dead cells by efferocytosis and the expression of hub gene Abca1 in MCAO mice models.

Investigating the Mechanistic of Danhong Injection in Brain Damage Caused by Cardiac I/R Injury via Bioinformatics, Computer Simulation, and Experimental Validation

OBJECTIVE

Cardiac ischemia-reperfusion (I/R) injury has negative effects on the brain and can even lead to the occurrence of ischemic stroke. Clinical evidence shows that Danhong injection (DHI) protects the heart and brain following ischemic events. This study investigated the mechanisms and key active compounds underlying the therapeutic effect of DHI against brain damage induced by cardiac I/R injury.

METHODS

The gene expression omnibus database provided GSE66360 and GSE22255 data sets. The R programming language was used to identify the common differentially expressed genes (cDEGs). Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed, and protein-protein interaction network was constructed. Active compounds of DHI were collected from the Traditional Chinese Medicine Systems Pharmacology database. Molecular docking and molecular dynamics simulations were performed. The MMPBSA method was used to calculate the binding-free energy. The pkCSM server and DruLiTo software were used for Absorption, Distribution, metabolism, excretion, and toxicity (ADMET) analysis and drug-likeness analysis. Finally, in vitro experiments were conducted to validate the results.

RESULTS

A total of 27 cDEGs had been identified. The PPI and enrichment results indicated that TNF-α was considered to be the core target. A total of 80 active compounds were retrieved. The molecular docking results indicated that tanshinone I (TSI), tanshinone IIA (TSIIA), and hydroxyl safflower yellow A (HSYA) were selected as core active compounds. Molecular dynamics verification revealed that the conformations were relatively stable without significant fluctuations. MMPBSA analysis revealed that the binding energies of TSI, TSIIA, and HSYA with TNF-α were -36.01, -21.71, and -14.80 kcal/mol, respectively. LEU57 residue of TNF-α has the highest contribution. TSI and TSIIA passed both the ADMET analysis and drug-likeness screening, whereas HSYA did not. Experimental verification confirmed that DHI and TSIIA reduced the expression of TNF-α, NLRP3, and IL-1β in the injured H9C2 and rat brain microvascular endothelial cells.

CONCLUSION

TNF-α can be considered to be a key target for BD-CI/R. TSIIA in DHI exerts a significant inhibitory effect on the inflammatory damage of BD-CI/R, providing new insights for future drug development.

[Upregulating KLF11 ameliorates intestinal inflammation in mice with 2, 4, 6-trinitrobenesulfonic acid-induced colitis by inhibiting the JAK2/STAT3 signaling pathway]

OBJECTIVE

To investigate the expression level of Kruppel-like transcription factor family member KLF11 in intestinal mucosal tissues of Crohn's disease (CD) and its regulatory effect on intestinal inflammation in CD-like colitis.

METHODS

We examined KLF11 expression levels in diseased and normal colon mucosal tissues from 12 CD patients and 12 patients with colorectal cancer using immunofluorescence staining. KLF11 expression was also detected in the colon mucosal tissues of a mouse model of 2, 4, 6-trinitrobenesulfonic acid (TNBS)-induced colitis. A recombinant adenoviral vector was used to upregulate KLF11 expression in the mouse models and the changes in intestinal inflammation was observed. A Caco-2 cell model with stable KLF11 overexpression was constructed by lentiviral infection. The effect of KLF11 overexpression on expressions of JAK2/STAT3 signaling pathway proteins was investigated using immunoblotting in both the mouse and cell models. The mouse models were treated with coumermycin A1, a JAK2/STAT3 signaling pathway agonist, and the changes in intestinal inflammatory responses were observed.

RESULTS

The expression level of KLF11 was significantly lowered in both the clinical specimens of diseased colon mucosal tissues and the colon tissues of mice with TNBS-induced colitis (P < 0.05). Adenovirus-mediated upregulation of KLF11 significantly improved intestinal inflammation and reduced the expression levels of inflammatory factors in the intestinal mucosa of the colitis mouse models (P < 0.05). Overexpression of KLF11 significantly inhibited the expression levels of p-JAK2 and p-STAT3 in intestinal mucosal tissues of the mouse models and in Caco-2 cells (P < 0.05). Treatment with coumermycin A1 obviously inhibited the effect of KLF11 upregulation for improving colitis and significantly increased the expression levels of inflammatory factors in the intestinal mucosa of the mouse models (P < 0.05).

CONCLUSION

KLF11 is downregulated in the intestinal mucosa in CD, and upregulation of KLF11 can improve intestinal inflammation and reduce the production of inflammatory factors probably by inhibiting the JAK2/STAT3 signaling pathway.

FDA compound library screening Baicalin upregulates TREM2 for the treatment of cerebral ischemia-reperfusion injury

Acute ischemic stroke (AIS) is a leading cause of global incidence and mortality rates. Oxidative stress and inflammation are key factors in the pathogenesis of AIS neuroinjury. Therefore, it is necessary to develop drugs that target neuroinflammation and oxidative stress in AIS. The Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), primarily expressed on microglial cell membranes, plays a critical role in reducing inflammation and oxidative stress in AIS. In this study, we employed a high-throughput screening (HTS) strategy to evaluate 2625 compounds from the (Food and Drug Administration) FDA library in vitro to identify compounds that upregulate the TREM2 receptor on microglia. Through this screening, we identified Baicalin as a potential drug for AIS treatment. Baicalin, a flavonoid compound extracted and isolated from the root of Scutellaria baicalensis, demonstrated promising results. Next, we established an in vivo mouse model of cerebral ischemia-reperfusion injury (MCAO/R) and an in vitro microglia cell of oxygen-glucose deprivation reperfusion (OGD/R) to investigate the role of Baicalin in inflammation injury, oxidative stress, and neuronal apoptosis. Our results showed that baicalin effectively inhibited microglia activation, reactive oxygen species (ROS) production, and inflammatory responses in vitro. Additionally, baicalin suppressed neuronal cell apoptosis. In the in vivo experiments, baicalin not only improved neurological functional deficits and reduced infarct volume but also inhibited microglia activation and inflammatory responses. Overall, our findings demonstrate the efficacy of Baicalin in treating MCAO/R by upregulating TREM2 to reduce inflammatory responses and inhibit neuronal apoptosis.

Enriched Environment Inhibits Neurotoxic Reactive Astrocytes via JAK2-STAT3 to Promote Glutamatergic Synaptogenesis and Cognitive Improvement in Chronic Cerebral Hypoperfusion Rats

Chronic cerebral hypoperfusion (CCH) is a primary contributor to cognitive decline in the elderly. Enriched environment (EE) is proved to improve cognitive function. However, mechanisms involved remain unclear. The purpose of the study was exploring the mechanisms of EE in alleviating cognitive deficit in rats with CCH. To create a rat model of CCH, 2-vessel occlusion (2-VO) surgery was performed. All rats lived in standard or enriched environments for 4 weeks. Cognitive function was assessed using the novel object recognition test and Morris water maze test. The protein levels of glutamatergic synapses, neurotoxic reactive astrocytes, reactive microglia, and JAK2-STAT3 signaling pathway were measured using Western blot. The mRNA levels of synaptic regulatory factors, C1q, TNF-α, and IL-1α were identified using quantitative PCR. Immunofluorescence was used to detect glutamatergic synapses, neurotoxic reactive astrocytes, and reactive microglia, as well as the expression of p-STAT3 in astrocytes in the hippocampus. The results demonstrated that the EE mitigated cognitive impairment in rats with CCH and enhanced glutamatergic synaptogenesis. EE also inhibited the activation of neurotoxic reactive astrocytes. Moreover, EE downregulated microglial activation, levels of C1q, TNF-α and IL-1α and phosphorylation of JAK2 and STAT3. Our results suggest that inhibition of neurotoxic reactive astrocytes may be one of the mechanisms by which EE promotes glutamatergic synaptogenesis and improves cognitive function in rats with CCH. The downregulation of reactive microglia and JAK2-STAT3 signaling pathway may be involved in this process.

Mitochondria-associated endoplasmic reticulum membranes tethering protein VAPB-PTPIP51 protects against ischemic stroke through inhibiting the activation of autophagy

AIMS

Mitochondria-associated endoplasmic reticulum membranes (MAMs) serve as a crucial bridge connecting the endoplasmic reticulum (ER) and mitochondria within cells. Vesicle-associated membrane protein-associated protein B (VAPB) and protein tyrosine phosphatase interacting protein 51 (PTPIP51) are responsible for the formation and stability of MAMs, which have been implicated in the pathogenesis of various diseases. However, the role of MAMs in ischemic stroke (IS) remains unclear. We aimed to investigate the role of MAMs tethering protein VAPB-PTPIP51 in experimental cerebral ischemia.

METHODS

We simulated cerebral ischemia-reperfusion injury (CIRI) by using a mouse middle cerebral artery occlusion (MCAO) model.

RESULTS

We observed a decrease in VAPB-PTPIP51 expression in the brain tissue. Our findings suggested compromised MAMs after MCAO, as a decreased mitochondria-ER contact (MERC) coverage and an increased distance were observed through the transmission electron microscope (TEM). Upon VAPB or PTPIP51 knockdown, the damage to MAMs was exacerbated, accompanied by excessive autophagy activation and increased reactive oxygen species (ROS) production, resulting in an enlarged infarct area and exacerbated neurological deficits. Notably, we observed that this damage was concomitant with the inhibition of the PI3K/AKT/mTOR pathway and was successfully mitigated by the treatment with the PI3K activator.

CONCLUSIONS

Our findings suggest that the downregulation of VAPB-PTPIP51 expression after IS mediates structural damage to MAMs. This may exacerbate CIRI by inhibiting the PI3K pathway and activating autophagy, thus providing new therapeutic targets for IS.

Sustained release of vascular endothelial growth factor A and basic fibroblast growth factor from nanofiber membranes reduces oxygen/glucose deprivation-induced injury to neurovascular units

Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor (VEGFA/bFGF) expression in the penumbra of cerebral ischemia can increase vascular volume, reduce lesion volume, and enhance neural cell proliferation and differentiation, thereby exerting neuroprotective effects. However, the beneficial effects of endogenous VEGFA/bFGF are limited as their expression is only transiently increased. In this study, we generated multilayered nanofiber membranes loaded with VEGFA/bFGF using layer-by-layer self-assembly and electrospinning techniques. We found that a membrane containing 10 layers had an ideal ultrastructure and could efficiently and stably release growth factors for more than 1 month. This 10-layered nanofiber membrane promoted brain microvascular endothelial cell tube formation and proliferation, inhibited neuronal apoptosis, upregulated the expression of tight junction proteins, and improved the viability of various cellular components of neurovascular units under conditions of oxygen/glucose deprivation. Furthermore, this nanofiber membrane decreased the expression of Janus kinase-2/signal transducer and activator of transcription-3 (JAK2/STAT3), Bax/Bcl-2, and cleaved caspase-3. Therefore, this nanofiber membrane exhibits a neuroprotective effect on oxygen/glucose-deprived neurovascular units by inhibiting the JAK2/STAT3 pathway.

Circular RNA PTP4A2 regulates microglial polarization through STAT3 to promote neuroinflammation in ischemic stroke

OBJECTIVE

Microglial polarization plays a critical role in neuroinflammation and may be a potential therapeutic target for ischemic stroke. This study was to explore the role and underlying molecular mechanism of Circular RNA PTP4A2 (circPTP4A2) in microglial polarization after ischemic stroke.

METHODS

C57BL/6J mice underwent transient middle cerebral artery occlusion (tMCAO), while primary mouse microglia and BV2 microglial cells experienced oxygen glucose deprivation/reperfusion (OGD/R) to mimic ischemic conditions. CircPTP4A2 shRNA lentivirus and Colivelin were used to knock down circPTP4A2 and upregulate signal transducer and activator of transcription 3 (STAT3) phosphorylation, respectively. Microglial polarization was assessed using immunofluorescence staining and Western blot. RNA pull-down and RNA binding protein immunoprecipitation (RIP) were applied to detect the binding between circPTP4A2 and STAT3.

RESULTS

The levels of circPTP4A2 were significantly increased in plasma and peri-infarct cortex in tMCAO mice. CircPTP4A2 knockdown reduced infarct volume, increased cortical cerebral blood flow (CBF), and attenuated neurological deficits. It also decreased pro-inflammatory factors levels in peri-infarct cortex and plasma, and increased anti-inflammatory factors concentrations 24 h post-stroke. In addition, circPTP4A2 knockdown suppressed M1 microglial polarization and promoted M2 microglial polarization in both tMCAO mice and OGD/R-induced BV2 microglial cells. Moreover, circPTP4A2 knockdown inhibited the phosphorylation of STAT3 induced by oxygen-glucose deprivation. In contrast, increased phosphorylation of STAT3 partly counteracted the effects of circPTP4A2 knockdown. RNA pull-down and RIP assays further certified the binding between circPTP4A2 and STAT3.

CONCLUSION

These results revealed regulatory mechanisms of circPTP4A2 that stimulated neuroinflammation by driving STAT3-dependent microglial polarization in ischemic brain injury. CircPTP4A2 knockdown reduced cerebral ischemic injury and promoted microglial M2 polarization, which could be a novel therapeutic target for ischemic stroke.

Resveratrol ameliorates glioblastoma inflammatory response by reducing NLRP3 inflammasome activation through inhibition of the JAK2/STAT3 pathway

OBJECTIVES

The aim of this study was to investigate the anti-tumor effect of resveratrol (RSV) on glioblastoma (GBM) and its specific mechanism in improving the inflammatory response of the tumor microenvironment. The tumor microenvironment of GBM is highly neuroinflammatory, inducing tumor immunosuppression. Therefore, ameliorating the inflammatory response is an important focus for anti-tumor research.

METHODS

The anti-tumor effect of RSV on GBM was demonstrated through in vitro cellular assays, including CCK-8, EdU, PI staining, Transwell, wound healing assay, and flow cytometry. Potential mechanisms of RSV's anti-GBM effects were identified through network pharmacological analysis. In addition, the relationship of RSV with the JAK2/STAT3 signaling pathway and the inflammasome NLRP3 was verified using Western blot.

RESULTS

RSV significantly inhibited cell viability in GBM cell lines LN-229 and U87-MG. Furthermore, it inhibited the proliferation and invasive migration ability of GBM cells, while promoting apoptosis. Network pharmacological analysis revealed a close association between the anti-GBM effects of RSV and the JAK/STAT signaling pathway, as well as inflammatory responses. Western blot analysis confirmed that RSV inhibited the over-activation of the inflammasome NLRP3 through the JAK2/STAT3 signaling pathway. Partial reversal of RSV's inhibition of inflammasome NLRP3 was observed with the addition of the JAK/STAT agonist RO8191.

CONCLUSIONS

In vitro, RSV can exert anti-tumor effects on GBM and improve the inflammatory response in the GBM microenvironment by inhibiting the activation of the JAK2/STAT3 signaling pathway. These findings provide new insights into potential therapeutic targets for GBM.

Lifibrate attenuates blood-brain barrier damage following ischemic stroke via the MLCK/p-MLC/ZO-1 axis

Dysfunction of tight junction proteins-associated damage to the blood-brain barrier (BBB) plays an important role in the pathogenesis of ischemic stroke. Lifibrate, an inhibitor of cholinephosphotransferase (CPT), has been used as an agent for serum lipid lowering. However, the protective effects of Lifibrate in ischemic stroke and the underlying mechanism have not been clearly elucidated. Here, we employed an in vivo mice model of MCAO and an OGD/R model in vitro. In the mice models, neurological deficit scores and infarct volume were assessed. Evans Blue solution was used to detect the BBB permeability. The TEER was examined to determine brain endothelial monolayer permeability. Here, we found that Lifibrate improved neurological dysfunction in stroke. Additionally, increased BBB permeability during stroke was significantly ameliorated by Lifibrate. Correspondingly, the reduced expression of the tight junction protein ZO-1 was restored by Lifibrate at both the mRNA and protein levels. Using an in vitro model, we found that Lifibrate ameliorated OGD/R-induced injury in human bEnd.3 brain microvascular endothelial cells by increasing cell viability but reducing the release of LDH. Importantly, Lifibrate suppressed the increase in endothelial monolayer permeability and the reduction in TEER induced by OGD/R via the rescue of ZO-1 expression. Mechanistically, Lifibrate blocked activation of the MLCK/ p-MLC signaling pathway in OGD/R-stimulated bEnd.3 cells. In contrast, overexpression of MLCK abolished the protective effects of Lifibrate in endothelial monolayer permeability, TEER, as well as the expression of ZO-1. Our results provide a basis for further investigation into the neuroprotective mechanism of Lifibrate during stroke.