Longxuetongluo capsule alleviates lipopolysaccharide-induced neuroinflammation by regulating multiple signaling pathways in BV2 microglia cells

Loureirin B protects against cerebral ischemia/reperfusion injury through modulating M1/M2 microglial polarization via STAT6 / NF-kappaB signaling pathway

The latest research indicates that modulating microglial polarization from M1 to M2 phenotype may be a coping therapy for ischemic stroke. The present study thereby evaluated the effects of loureirin B (LB), a monomer compound extracted from Sanguis Draconis flavones (SDF), on cerebral ischemic injury and the potential mechanisms. The middle cerebral artery occlusion (MCAO) model was established in male Sprague-Dawley rats to induce cerebral ischemia/reperfusion (I/R) injury in vivo, and BV2 cells were exposed to oxygen-glucose deprivation and reintroduction (OGD/R) to mimic cerebral I/R injury in vitro. The results showed that LB significantly reduced infarct volume, neurological deficits and neurobehavioral deficits, apparently improved histopathological changes and neuronal loss in cortex and hippocampus of MCAO/R rats, markedly decreased the proportion of M1 microglia cells and the level of pro-inflammatory cytokines, and increased the proportion of M2 microglia and the level of anti-inflammatory cytokines both in vivo and in vitro. In addition, LB evidently improved the p-STAT6 expression and reduced the NF-κB (p-p65) expression after cerebral I/R injury in vivo and in vitro. IL-4 (a STAT6 agonist) exhibited a similar impact to that of LB, while AS1517499 (a STAT6 inhibitor) significantly reversed the effect of LB on BV-2 cells after OGD/R. These findings point to the protection of LB against cerebral I/R injury by modulating M1/M2 polarization of microglia via the STAT6/NF-κB signaling pathway, hence LB may be a viable treatment option for ischemic stroke.

The pivotal role of JAK/STAT and IRS/PI3K signaling pathways in neurodegenerative diseases: Mechanistic approaches to polyphenols and alkaloids

BACKGROUND

Neurodegenerative diseases (NDDs) are characterized by progressive neuronal dysfunctionality which results in disability and human life-threatening events. In recent decades, NDDs are on the rise. Besides, conventional drugs have not shown potential effectiveness to attenuate the complications of NDDs. So, exploring novel therapeutic agents is an urgent need to combat such disorders. Accordingly, growing evidence indicates that polyphenols and alkaloids are promising natural candidates, possessing several beneficial pharmacological effects against diseases. Considering the complex pathophysiological mechanisms behind NDDs, Janus kinase (JAK), insulin receptor substrate (IRS), phosphoinositide 3-kinase (PI3K), and signal transducer and activator of transcription (STAT) seem to play critical roles during neurodegeneration/neuroregeneration. In this line, modulation of the JAK/STAT and IRS/PI3K signaling pathways and their interconnected mediators by polyphenols/alkaloids could play pivotal roles in combating NDDs, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), stroke, aging, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), depression and other neurological disorders.

PURPOSE

Thus, the present study aimed to investigate the neuroprotective roles of polyphenols/alkaloids as multi-target natural products against NDDs which are critically passing through the modulation of the JAK/STAT and IRS/PI3K signaling pathways.

STUDY DESIGN AND METHODS

A systematic and comprehensive review was performed to highlight the modulatory roles of polyphenols and alkaloids on the JAK/STAT and IRS/PI3K signaling pathways in NDDs, according to the PRISMA guideline, using scholarly electronic databases, including Scopus, PubMed, ScienceDirect, and associated reference lists.

RESULTS

In the present study 141 articles were included from a total of 1267 results. The results showed that phenolic compounds such as curcumin, epigallocatechin-3-gallate, and quercetin, and alkaloids such as berberine could be introduced as new strategies in combating NDDs through JAK/STAT and IRS/PI3K signaling pathways. This is the first systematic review that reveals the correlation between the JAK/STAT and IRS/PI3K axis which is targeted by phytochemicals in NDDs. Hence, this review highlighted promising insights into the neuroprotective potential of polyphenols and alkaloids through the JAK/STAT and IRS/PI3K signaling pathway and interconnected mediators toward neuroprotection.

CONCLUSION

Amongst natural products, phenolic compounds and alkaloids are multi-targeting agents with the most antioxidants and anti-inflammatory effects possessing the potential of combating NDDs with high efficacy and lower toxicity. However, additional reports are needed to prove the efficacy and possible side effects of natural products.

Pivotal regulatory roles of traditional Chinese medicine in ischemic stroke via inhibition of NLRP3 inflammasome

ETHNOPHARMACOLOGICAL RELEVANCE

Many studies have demonstrated the powerful neuroprotection abilities of multiple traditional Chinese medicines (TCMs) against NLRP3 inflammasome-mediated ischemic cerebral injury. These TCMs may be in the form of TCM prescriptions, Chinese herbal medicines and their extracts, and TCM monomers.

AIM OF THE STUDY

This review aimed to analyze and summarize the existing knowledge on the assembly and activation of the NLRP3 inflammasome and its role in the pathogenesis of ischemic stroke (IS). We also summarized the mechanism of action of the various TCMs on the NLRP3 inflammasome, which may provide new insights for the management of IS.

MATERIALS AND METHODS

We reviewed recently published articles by setting the keywords "NLRP3 inflammasome" and "traditional Chinese medicines" along with "ischemic stroke"; "NLRP3 inflammasome" and "ischemic stroke" along with "natural products" and so on in Pubmed and GeenMedical.

RESULTS

According to recent studies, 16 TCM prescriptions (officially authorized products and clinically effective TCM prescriptions), 7 Chinese herbal extracts, and 29 TCM monomers show protective effects against IS through anti-inflammatory, anti-oxidative stress, anti-apoptotic, and anti-mitochondrial autophagy effects.

CONCLUSIONS

In this review, we analyzed studies on the involvement of NLRP3 in IS therapy. Further, we comprehensively and systematically summarized the current knowledge to provide a reference for the further application of TCMs in the treatment of IS.

Detecting Key Functional Components Group and Speculating the Potential Mechanism of Xiao-Xu-Ming Decoction in Treating Stroke

Stroke is a cerebrovascular event with cerebral blood flow interruption which is caused by occlusion or bursting of cerebral vessels. At present, the main methods in treating stroke are surgical treatment, statins, and recombinant tissue-type plasminogen activator (rt-PA). Relatively, traditional Chinese medicine (TCM) has widely been used at clinical level in China and some countries in Asia. Xiao-Xu-Ming decoction (XXMD) is a classical and widely used prescription in treating stroke in China. However, the material basis of effect and the action principle of XXMD are still not clear. To solve this issue, we designed a new system pharmacology strategy that combined targets of XXMD and the pathogenetic genes of stroke to construct a functional response space (FRS). The effective proteins from this space were determined by using a novel node importance calculation method, and then the key functional components group (KFCG) that could mediate the effective proteins was selected based on the dynamic programming strategy. The results showed that enriched pathways of effective proteins selected from FRS could cover 99.10% of enriched pathways of reference targets, which were defined by overlapping of component targets and pathogenetic genes. Targets of optimized KFCG with 56 components can be enriched into 166 pathways that covered 80.43% of 138 pathways of 1,012 pathogenetic genes. A component potential effect score (PES) calculation model was constructed to calculate the comprehensive effective score of components in the components-targets-pathways (C-T-P) network of KFCGs, and showed that ferulic acid, zingerone, and vanillic acid had the highest PESs. Prediction and docking simulations show that these components can affect stroke synergistically through genes such as MEK, NFκB, and PI3K in PI3K-Akt, cAMP, and MAPK cascade signals. Finally, ferulic acid, zingerone, and vanillic acid were tested to be protective for PC12 cells and HT22 cells in increasing cell viabilities after oxygen and glucose deprivation (OGD). Our proposed strategy could improve the accuracy on decoding KFCGs of XXMD and provide a methodologic reference for the optimization, mechanism analysis, and secondary development of the formula in TCM.

Longxuetongluo Capsule protects against cerebral ischemia/reperfusion injury through endoplasmic reticulum stress and MAPK-mediated mechanisms

Introduction

Longxuetongluo Capsule (LTC) is wildly applied to treat ischemic stroke in clinical practice in China. However, the pharmacological mechanism of LTC on ischemic stroke is still unstated.

Objective

Our research was designed to study the protective effect of LTC against cerebral ischemia–reperfusion (I/R) injury and reveal the underlying mechanism both in vivo and in vitro.

Methods

PC12 cells treated with glucose deprivation/reperfusion (OGD/R) were used to simulate in vitro ischemia/reperfusion (I/R) injury. The cell viability, apoptosis rate, and protein expressions of PC12 cells were evaluated. In vivo validation of the protective effect of LTC was carried out by middle cerebral artery occlusion (MCAO)/reperfusion treatment, and the underlying mechanism of its anti-apoptosis ability was further revealed by immunohistochemistry staining and Western blotting.

Results

In the current study, we observed that LTC effectively inhibited oxygen-glucose deprivation/reperfusion (OGD/R) induced apoptosis of PC12 cells through suppressing the cleavage of poly ADP-ribose polymerase (PARP), caspase-3, and caspase-9. Further investigation revealed that OGD/R insult remarkably triggered the endoplasmic reticulum stress responses (ER stress) to induce PC12 cell apoptosis. LTC treatment alleviated OGD/R induced ER stress by inhibiting the activation of protein kinase RNA (PKR)-like ER kinase (PERK)/eukaryotic translation initiation factor 2 (eIF2α) and inositol requiring enzyme 1 (IRE1)/tumor necrosis factor receptor-associated factor 2 (TRAF2) pathways. Additionally, LTC also restrained the OGD/R-induced PC12 cell apoptosis by reversing the activated mitogen-activated protein kinase (MAPK) through IRE1/TRAF2 pathway. Animal studies demonstrated LTC significantly restricted the infarct region induced by middle cerebral artery occlusion (MCAO)/reperfusion, the activation of ER stress and apoptosis of neuronal cells had also been suppressed by LTC in the penumbra region.

Conclusion

LTC protects the cerebral neuronal cell against ischemia/reperfusion injury through ER stress and MAPK-mediated mechanisms.

Inhibition of Long Noncoding RNA SNHG15 Ameliorates Hypoxia/Ischemia-Induced Neuronal Damage by Regulating miR-302a-3p/STAT1/NF-κB Axis

PURPOSE

Ischemic brain injury results in high mortality and serious neurologic morbidity. Here, we explored the role of SNHG15 in modulating neuronal damage and microglial inflammation after ischemia stroke.

MATERIALS AND METHODS

The hypoxia/ischemia models were induced by middle cerebral artery occlusion in mice and oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Quantitative real-time PCR (qRT-PCR) and Western blot were conducted to determine the levels of SNHG15, miR-302a-3p, and STAT1/NF-κB. Moreover, gain- or loss-of functional assays of SNHG15 and miR-302a-3p were conducted. MTT assay was used to evaluate the viability of HT22 cells, and the apoptotic level was determined by flow cytometry. Furthermore, enzyme-linked immunosorbent assay was performed to detect oxidative stress and inflammatory mediators in the ischemia cortex and OGD/R-treated BV2 microglia.

RESULTS

The SNHG15 and STAT1/NF-κB pathways were both distinctly up-regulated, while miR-302a-3p was notably down-regulated in the ischemia cortex. Additionally, overexpressing SNHG15 dramatically enhanced OGD/R-mediated neuronal apoptosis as well as the expression of oxidative stress and inflammation factors from microglia. In contrast, knocking down SNHG15 or overexpressing miR-302a-3p relieved OGD/R-mediated neuronal apoptosis and microglial activation. Moreover, the rescue experiment testified that overexpressing miR-302a-3p also attenuated SNHG15 up-regulation-induced effects. In terms of the mechanisms, SNHG15 sponged miR-302a-3p and activated STAT1/NF-κB as a competitive endogenous RNA, while miR-302a-3p targeted STAT1 and negatively regulated the STAT1/NF-κB pathway.

CONCLUSION

SNHG15 was up-regulated in the hypoxia/ischemia mouse or cell model. The inhibition of SNHG15 ameliorates ischemia/hypoxia-induced neuronal damage and microglial inflammation by regulating the miR-302a-3p/STAT1/NF-κB pathway.

A Network Pharmacology-Based Analysis of the Protective Mechanism of Miao Medicine Xuemaitong Capsule Against Secondary Brain Damage in the Ischemic Area Surrounding Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating disease with the high mortality. The poor outcome of ICH is partially due to a combination of various secondary insults, including in the ischemic area. Xuemaitong capsule (XMT), a kind of traditional Chinese medicine, has been applied to clinic practice. The purpose of this study is to explore the mechanism of XMT in alleviating secondary damage in the ischemic area after ICH. We screened XMT target, compound components, and ICH-related targets using network pharmacology, cluster analysis, and enrichment analysis. We found that the tumor necrosis factor (TNF) signaling pathway might be the key signaling pathway for XMT treatment of ICH. An ICH rat model was established, as demonstrated by poor neurologic score. In the ICH rats, Western blot analysis and immunofluorescence indicated the upregulated expression of TNF receptor 1 (TNFR1), mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and caspase-3 (CASP3). Importantly, administration of XMT alleviated inflammation, edema, and increased perfusion in the ischemic area, whereas the expression of TNFR1, MAPK, NF-κB, and CASP3 was decreased. Furthermore, Fluoro-Jade B and terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling staining revealed that XMT application also inhibited apoptosis and degradation of ischemic area neurons. In conclusion, this evidence elucidates that XMT alleviates neuron apoptosis, ischemic area inflammation, edema, and perfusion through the TNFR1-mediated CASP3/NF-κB/MAPK axis. SIGNIFICANCE STATEMENT: Tumor necrosis factor (TNF) is the key signaling pathway of Xuemaitong (XMT) to intervention during intracerebral hemorrhage. Fourteen key targets [intercellular adhesion molecule 1, interleukin (IL) 6, TNF, C-C motif chemokine ligand 2, prostaglandin-endoperoxide synthase 2, v-rel reticuloendotheliosis viral oncogene homolog A, matrix metalloproteinase 9, endothelin-1 (EDN1), mitogen-activated protein kinase (MAPK) 1, fos proto-oncogene protein, caspase-3 (CASP3), jun proto-oncogene, IL1B, MAPK8] are retrieved from the data base. XMT can inhibit neuron apoptosis in the ischemic area via regulating TNF receptor 1 (TNFR1)/CASP3. XMT alleviates inflammation and edema through regulating TNFR1/nuclear factor-κB and TNFR1/MAPK signaling pathways. XMT alleviates hypoperfusion in the cerebral ischemic area through mediating TNFR1/MAPK/EDN1.

Forsythoside B attenuates memory impairment and neuroinflammation via inhibition on NF-κB signaling in Alzheimer's disease

Background

Neuroinflammation is a principal element in Alzheimer’s disease (AD) pathogenesis, so anti-inflammation may be a promising therapeutic strategy. Forsythoside B (FTS•B), a phenylethanoid glycoside isolated from Forsythiae fructus, has been reported to exert anti-inflammatory effects. However, no studies have reported whether the anti-inflammatory properties of FTS•B have a neuroprotective effect in AD. In the present study, these effects of FTS•B were investigated using amyloid precursor protein/presenilin 1 (APP/PS1) mice, BV-2 cells, and HT22 cells.

Methods

APP/PS1 mice were administered FTS•B intragastrically for 36 days. Behavioral tests were then carried out to examine cognitive functions, including the Morris water maze, Y maze, and open field experiment. Immunohistochemistry was used to analyze the deposition of amyloid-beta (Aβ), the phosphorylation of tau protein, and the levels of 4-hydroxynonenal, glial fibrillary acidic protein, and ionized calcium-binding adapter molecule 1 in the hippocampus. Proteins that showed marked changes in levels related to neuroinflammation were identified using proteomics and verified using enzyme-linked immunosorbent assay and western blot. BV-2 and HT22 cells were also used to confirm the anti-neuroinflammatory effects of FTS•B.

Results

In APP/PS1 mice, FTS•B counteracted cognitive decline, ameliorated the deposition of Aβ and the phosphorylation of tau protein, and attenuated the activation of microglia and astrocytes in the cortex and hippocampus. FTS•B affected vital signaling, particularly by decreasing the activation of JNK-interacting protein 3/C-Jun NH2-terminal kinase and suppressing WD-repeat and FYVE-domain-containing protein 1/toll-like receptor 3 (WDFY1/TLR3), further suppressing the activation of nuclear factor-κB (NF-κB) signaling. In BV-2 and HT22 cells, FTS•B prevented lipopolysaccharide-induced neuroinflammation and reduced the microglia-mediated neurotoxicity.

Conclusions

FTS•B effectively counteracted cognitive decline by regulating neuroinflammation via NF-κB signaling in APP/PS1 mice, providing preliminary experimental evidence that FTS•B is a promising therapeutic agent in AD treatment.

Activation of Nrf2 by Natural Bioactive Compounds: A Promising Approach for Stroke?

Stroke represents one of the main causes of disability and death worldwide. The pathological subtypes of stroke are ischemic stroke, the most frequent, and hemorrhagic stroke. Nrf2 is a transcription factor that regulates redox homeostasis. In stress conditions, Nrf2 translocates inside the nucleus and induces the transcription of enzymes involved in counteracting oxidative stress, endobiotic and xenobiotic metabolism, regulators of inflammation, and others. Different natural compounds, including food and plant-derived components, were shown to be able to activate Nrf2, mediating an antioxidant response. Some of these compounds were tested in stroke experimental models showing several beneficial actions. In this review, we focused on the studies that evidenced the positive effects of natural bioactive compounds in stroke experimental models through the activation of Nrf2 pathway. Interestingly, different natural compounds can activate Nrf2 through multiple pathways, inducing a strong antioxidant response associated with the beneficial effects against stroke. According to several studies, the combination of different bioactive compounds can lead to a better neuroprotection. In conclusion, natural bioactive compounds may represent new therapeutic strategies against stroke.