Icariin inhibits the expression of IL-1β, IL-6 and TNF-α induced by OGD/R through the IRE1/XBP1s pathway in microglia

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.

The immunomodulatory mechanism of acupuncture treatment for ischemic stroke: research progress, prospects, and future direction

Ischemic stroke (IS) is one of the leading causes of death and disability. Complicated mechanisms are involved in the pathogenesis of IS. Immunomodulatory mechanisms are crucial to IS. Acupuncture is a traditional non-drug treatment that has been extensively used to treat IS. The exploration of neuroimmune modulation will broaden the understanding of the mechanisms underlying acupuncture treatment. This review summarizes the immune response of immune cells, immune cytokines, and immune organs after an IS. The immunomodulatory mechanisms of acupuncture treatment on the central nervous system and peripheral immunity, as well as the factors that influence the effects of acupuncture treatment, were summarized. We suggest prospects and future directions for research on immunomodulatory mechanisms of acupuncture treatment for IS based on current progress, and we hope that these will provide inspiration for researchers. Additionally, acupuncture has shown favorable outcomes in the treatment of immune-based nervous system diseases, generating new directions for research on possible targets and treatments for immune-based nervous system diseases.

Preventive noninvasive vagal nerve stimulation reduces insufficient sleep-induced depression by improving the autonomic nervous system

BACKGROUND

Depression is closely linked to an imbalance in the autonomic nervous system (ANS). However, the role of this imbalance in mediating the effects of sleep deprivation (SD) and vagus nerve stimulation (VNS) on emotional well-being is not fully understood.

METHODS

A population-based analysis was conducted to explore the relationship between sleep duration, depression scores, and heart rate variability (HRV). Additionally, the chronic SD mouse model was established to assess the impact of preventive transcutaneous auricular VNS (taVNS) on pathological and behavioral changes.

RESULTS

Our study found a significant link between sleep duration, depression severity, and HRV. Shorter sleep duration was associated with higher depression scores and lower RMSSD (a measure of HRV). In our rat model, insufficient sleep consistently impaired HRV. This effect was mitigated by taVNS, accompanied by corresponding changes in levels of IL-1β and IL-6, astrocyte and microglia activation, and tail suspension times.

CONCLUSIONS

Using VNS as a preventive treatment for depression-risk individuals with insufficient sleep shows promise. It not only broadens the potential applications of VNS but also sheds light on its mechanism-particularly its role in enhancing vagal nerve function and balancing the ANS, as evidenced by HRV measurements.

Therapeutic strategies targeting the NLRP3‑mediated inflammatory response and pyroptosis in cerebral ischemia/reperfusion injury (Review)

Ischemic stroke poses a major threat to human health. Therefore, the molecular mechanisms of cerebral ischemia/reperfusion injury (CIRI) need to be further clarified, and the associated treatment approaches require exploration. The NOD‑like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome serves an important role in causing CIRI, and its activation exacerbates the underlying injury. Activation of the NLRP3 inflammasome triggers the maturation and production of the inflammatory molecules IL‑1β and IL‑18, as well as gasdermin‑D‑mediated pyroptosis and CIRI damage. Thus, the NLRP3 inflammasome may be a viable target for the treatment of CIRI. In the present review, the mechanisms of the NLRP3 inflammasome in the intense inflammatory response and pyroptosis induced by CIRI are discussed, and the therapeutic strategies that target the NLRP3‑mediated inflammatory response and pyroptosis in CIRI are summarized. At present, certain drugs have already been studied, highlighting future therapeutic perspectives.

Activation of Notch-1 signaling pathway in macrophages to secrete PD-L1 and regulate cytotoxicity of CAR-T cells in diffuse large B-cell lymphoma

OBJECTIVE

To investigate the mechanism of action of the Notch-1/IRE1/XBP1s signaling pathway in diffuse large B-cell lymphoma (DLBCL).

METHODS

The expressions of relevant proteins were detected by Western blotting. The effect of myeloid-specific knockout of Notch-1 on lymphoma progression was observed by mouse tumor transplantation and imaging. The apoptosis of chimeric antigen receptor T-cell therapy (CAR-T) cells were detected by flow cytometry, and the proliferation of CAR-T cells was detected by wound healing assay and cell counting kit-8 (CCK8) assay.

RESULTS

Lymphoma cells mediated the Notch-1 signaling pathway in bone marrow-derived macrophages and promoted the activation of STAT3 and STAT6 in bone marrow-derived macrophages. Myeloid-specific knockout of Notch-1 could inhibit the progression of lymphoma. Lymphoma cells enhanced the expression of p-PERK, p-IRE1α, ATF6, IL-6, IL-4, p-AKT, CD9, CD63 and PD-L1 in bone marrow-derived macrophages by mediating the Notch-1 signaling pathway. Knockout of Notch-1 in macrophages alleviated, to some extent, the suppression of killing activity of CAR-T cells, while activation of Notch-1 in macrophages inhibited proliferation and promoted apoptosis of CAR-T cells. The PD-L1 antibody significantly restored the cytotoxicity and proliferation of CAR-T cells, and inhibited their apoptosis.

CONCLUSION

Activation of the Notch-1/IRE1/XBP1s signaling pathway in myeloid macrophages promotes the secretion of IL-6 and IL-4 as well as PD-L1, thereby inhibiting the activity and proliferation of CAR-T cells and promoting their apoptosis.

[Sulforaphane reverses Aβ fiber-mediated M1 type microglia polarization and neuroinflammation-mediated necroptosis of neural stem cells by downregulating the MAPK/NF-κB signaling pathways]

OBJECTIVE

To explore the effects of sulforaphane (SFN) and Aβ25-35 fibers (fAβ25-35) on M1/M2 polarization of BV-2 cells and neuroinflammation-mediated programmed necrosis of neural stem cells.

METHODS

BV-2 cells treated with different concentrations of fAβ25-35 and SFN were examined for changes in cell viability using the CCK-8 kit. The effect of fAβ25-35 alone or in combination with SFN or SB203580 on expressions of IL-6 and TNF-α mRNA and proteins were assessed in BV-2 cells using RT-qPCR and ELISA. CD16/32 and CD206 in the treated cells were analyzed with flow cytometry, and the cellular expressions of p-p38 and p-p65 protein were detected with Western blotting. C17.2 cells co-cultured with BV-2 cells for 24 h were examined for p-mlkl protein expression using Western blotting.

RESULTS

fAβ25-35 at the concentration of 6.25 μmol/L significantly increased the viability of BV-2 cells (P < 0.01) whereas fAβ25-35 beyond 50 μmol/L decreased the cell viability (P < 0.0001). Treatment of BV-2 cells with SFN below 10 μmol/L for 24 h did not significant affect the cell viability (P > 0.05). BV-2 cells treated with fAβ25-35 alone, as compared with the cells in the other 3 groups, showed significantly increased IL-6 and TNF-α mRNA and protein expressions (P < 0.001), enhanced CD16/32 expression (P < 0.05), lowered CD206 expression (P < 0.01), and increased protein expressions of p-p38 and p- p65 (P < 0.01). C17.2 cells co-cultured with BV-2 cells treated with fAβ25-35, compared with the combined treatments, showed a significant reduction in the protein expression of p-mlkl (P < 0.05).

CONCLUSION

SFN reverses M1 type microglia polarization and neuroinflammation-mediated programmed necrosis of neural stem cells by downregulating the MAPK/NF-κB signaling pathway in Aβ25-35-activated BV-2 cells.

Anti-inflammatory effects of icariin in the acute and chronic phases of the mouse pilocarpine model of epilepsy

Neuroinflammation mediated by microglia made a significant contribution in the pathophysiology of epilepsy. Icariin (ICA), a bioactive ingredient isolated from Epimedium, has been shown to present both antioxidant and anti-inflammatory properties. This study was to explore the potential therapeutic effects of icariin on mouse pilocarpine model of epilepsy and its underlying mechanisms in vivo and in vitro. To this end, we firstly measured the serum concentrations of the proinflammatory cytokines IL-1β and IL-6 from patients with temporal lobe epilepsy and found that patients with a higher seizure frequency showed correspondingly higher inflammatory reaction. Mouse pharmacokinetic study, transmembrane transportation assay, and cell viability assay collectively demonstrated that ICA was able to cross the blood-brain barrier and has good biocompatibility. The acute and chronic epilepsy models were next established in a pilocarpine mouse model of acquired epilepsy. Icariin has been identified that it could cross the blood-brain barrier and enter the hippocampus to exhibit therapeutic effects. ICA treatment dramatically promoted microglial polarization to the M2 phenotype in epilepsy mice both in the acute and chronic phases. Reduced release of M1-associated proinflammatory factors, such as IL-1β and IL-6, corroborates the altered glial cell polarization. Furthermore, ICA alleviated seizure intensity and mortality in acute phase epileptic mice. Models in the chronic group also showed improved general condition, cognition ability, and memory function after ICA treatment. Taken together, our research strongly suggested that icariin has the potential to treat epilepsy via inhibiting neuroinflammation by promoting microglial polarization to the M2 phenotype.

TSG-6 alleviates cerebral ischemia/reperfusion injury and blood-brain barrier disruption by suppressing ER stress-mediated inflammation

Tumor necrosis factor-stimulated gene-6 (TSG-6) exhibits promising neuroprotective activity, but how it influences cerebral ischemia/reperfusion (CIR) injury remains to be established. Here, the impact of TSG-6 on the CIR-induced disturbance in the blood-brain barrier (BBB) and associated neurological degeneration was assessed, and the related molecular processes were explored. In this study, TSG-6 markedly reduced CIR-mediated increases in neurological deficit scores, decreased infarct volume, and protected against the apoptotic death of neurons in MCAO/R model rats. Similarly, TSG-6 pretreatment protected cultured neurons against OGD/R-associated neuronal death. TSG-6 also restored BBB integrity, suppressing PERK-eIF2α and IRE1α-TRAF2 pathway activation in CIR model systems, thereby inhibiting NF-κB, TNF-α, IL-1β, and IL-6. The further use of specific inhibitors of ER stress, 4-phenyl butyric acid (4-PBA), PERK (GSK2656157), and IRE1α (STF083010) demonstrated the ability of ER stress to drive inflammatory activity in the context of CIR injury i the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways. Consistently, the activation of ER stress using tunicamycin resulted in reversing the beneficial effects of TSG-6 on CIR-associated BBB disruption and neurological damage in vitro and in vivo. Treatment with TSG-6 can protect against CIR injury via the inhibition of ER stress-related inflammatory activity induced through the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways.

Anti-Inflammatory Effects of Flavonoids in Common Neurological Disorders Associated with Aging

Aging reduces homeostasis and contributes to increasing the risk of brain diseases and death. Some of the principal characteristics are chronic and low-grade inflammation, a general increase in the secretion of proinflammatory cytokines, and inflammatory markers. Aging-related diseases include focal ischemic stroke and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Flavonoids are the most common class of polyphenols and are abundantly found in plant-based foods and beverages. A small group of individual flavonoid molecules (e.g., quercetin, epigallocatechin-3-gallate, and myricetin) has been used to explore the anti-inflammatory effect in vitro studies and in animal models of focal ischemic stroke and AD and PD, and the results show that these molecules reduce the activated neuroglia and several proinflammatory cytokines, and also, inactivate inflammation and inflammasome-related transcription factors. However, the evidence from human studies has been limited. In this review article, we highlight the evidence that individual natural molecules can modulate neuroinflammation in diverse studies from in vitro to animal models to clinical studies of focal ischemic stroke and AD and PD, and we discuss future areas of research that can help researchers to develop new therapeutic agents.

Treatment of Ischemic Stroke With Wenyang Huayu Formula: Network Pharmacology Analysis and Experimental Validation

Context: Wenyang Huayu formula (WYHYF) is a prescription useful for treating stroke. Objective: To evaluate the mechanism of WYHYF in the treatment of ischemic stroke. Materials and methods: Network pharmacology analysis was performed to identify the chemical components and potential targets of WYHYF related to cerebral ischemia-reperfusion. The Cytoscape software and STRING database were used to draw a “drug component target disease” and protein interaction network diagram, respectively. Metascape database was used for gene enrichment analysis, and Autodock vina software was used for molecular docking to determine the pathways and targets of WYHYF. Finally, the pathways and targets were verified in vivo in rats. Results: We identified 277 drug targets and 3777 disease targets of WYHYF. Enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes pathways yielded 222 entries. The results of molecular docking showed that the core components and core proteins had a good binding ability. Validation analysis in the animal model indicated that stigmasterol, C-homoerythrin, luteolin, and other components in WYHYF influence the effects of the Toll-like receptor 4(TLR4)/NF-κB signal pathway on IL-6, IL-1β, and tumor necrosis factor-alpha-α and exert neuroprotective effects, relieve reperfusion injury, and inhibit apoptosis and inflammation. Discussion and conclusions: WYHYF affects ischemic stroke through the interactions of multiple components, targets, and pathways. The mechanism may involve the TLR4/NF-κB signal pathway to inhibit apoptosis, reduce inflammation, and promote angiogenesis.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Molecular Mechanism Underlying Role of the XBP1s in Cardiovascular Diseases

Spliced X-box binding protein-1 (XBP1s) is a protein that belongs to the cAMP-response element-binding (CREB)/activating transcription factor (ATF) b-ZIP family with a basic-region leucine zipper (bZIP). There is mounting evidence to suggest that XBP1s performs a critical function in a range of different cardiovascular diseases (CVDs), indicating that it is necessary to gain a comprehensive knowledge of the processes involved in XBP1s in various disorders to make progress in research and clinical therapy. In this research, we provide a summary of the functions that XBP1s performs in the onset and advancement of CVDs such as atherosclerosis, hypertension, cardiac hypertrophy, and heart failure. Furthermore, we discuss XBP1s as a novel therapeutic target for CVDs.

Icariin-loaded hydrogel with concurrent chondrogenesis and anti-inflammatory properties for promoting cartilage regeneration in a large animal model

Currently, an effective repair method that can promote satisfactory cartilage regeneration is unavailable for cartilage damages owing to inevitable inflammatory erosion. Cartilage tissue engineering has revealed considerable treatment options for cartilage damages. Icariin (ICA) is a flavonoid component of Epimedii folium with both chondrogenic and anti-inflammatory properties. In this study, we prepared an ICA/CTS hydrogel by loading ICA into chitosan (CTS) hydrogel to impart chondrogenesis and anti-inflammatory properties to the ICA/CTS hydrogel. In vitro results revealed that ICA showed sustained release kinetics from the ICA/CTS hydrogel. In addition, compared to the CTS hydrogel, the ICA/CTS hydrogel exhibited a favorable in vitro anti-inflammatory effect upon incubation with lipopolysaccharide pre-induced RAW264.7 macrophages, as indicated by the suppression of inflammatory-related cytokines (IL-6 and TNF-α). Additionally, when co-cultured with chondrocytes in vitro, the ICA/CTS hydrogel showed good cytocompatibility, accelerated chondrocyte proliferation, and enhanced chondrogenesis compared to the CTS hydrogel. Moreover, the in vitro engineered cartilage from the chondrocyte-loaded ICA/CTS hydrogel achieved stable cartilage regeneration when subcutaneously implanted in a goat model. Finally, the addition of ICA endowed the ICA/CTS hydrogel with a potent anti-inflammatory effect compared to what was observed in the CTS hydrogel, as confirmed by the attenuated IL-1β, IL-6, TNF-α, and TUNEL expression. The prepared ICA/CTS hydrogel offered an effective method of delivery for chondrogenic and anti-inflammatory agents and served as a useful platform for cartilage regeneration in an immunocompetent large animal model.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

NLRP3 Inflammasome Activation: A Therapeutic Target for Cerebral Ischemia–Reperfusion Injury

Millions of patients are suffering from ischemic stroke, it is urgent to figure out the pathogenesis of cerebral ischemia–reperfusion (I/R) injury in order to find an effective cure. After I/R injury, pro-inflammatory cytokines especially interleukin-1β (IL-1β) upregulates in ischemic brain cells, such as microglia and neuron. To ameliorate the inflammation after cerebral I/R injury, nucleotide-binding oligomerization domain (NOD), leucine-rich repeat (LRR), and pyrin domain-containing protein 3 (NLRP3) inflammasome is well-investigated. NLRP3 inflammasomes are complicated protein complexes that are activated by endogenous and exogenous danger signals to participate in the inflammatory response. The assembly and activation of the NLRP3 inflammasome lead to the caspase-1-dependent release of pro-inflammatory cytokines, such as interleukin (IL)-1β and IL-18. Furthermore, pyroptosis is a pro-inflammatory cell death that occurs in a dependent manner on NLRP3 inflammasomes after cerebral I/R injury. In this review, we summarized the assembly and activation of NLRP3 inflammasome; moreover, we also concluded the pivotal role of NLRP3 inflammasome and inhibitors, targeting the NLRP3 inflammasome in cerebral I/R injury.

Cerebral Glucose Metabolism and Potential Effects on Endoplasmic Reticulum Stress in Stroke

Ischemic stroke is an extremely common pathology with strikingly high morbidity and mortality rates. The endoplasmic reticulum (ER) is the primary organelle responsible for conducting protein synthesis and trafficking as well as preserving intracellular Ca2⁺ homeostasis. Mounting evidence shows that ER stress contributes to stroke pathophysiology. Moreover, insufficient circulation to the brain after stroke causes suppression of ATP production. Glucose metabolism disorder is an important pathological process after stroke. Here, we discuss the relationship between ER stress and stroke and treatment and intervention of ER stress after stroke. We also discuss the role of glucose metabolism, particularly glycolysis and gluconeogenesis, post-stroke. Based on recent studies, we speculate about the potential relationship and crosstalk between glucose metabolism and ER stress. In conclusion, we describe ER stress, glycolysis, and gluconeogenesis in the context of stroke and explore how the interplay between ER stress and glucose metabolism contributes to the pathophysiology of stroke.