TLR4 /NF-ĸB and JAK2/STAT3 signaling pathways: Cellular signaling pathways targeted by cell-conditioned medium therapy in protection against ischemic stroke

The protective effects of gallic acid and SGK1 inhibitor on cardiac damage and genes involved in Ca2+ homeostasis in an isolated heart model of ischemia/reperfusion injury in rat

Serum and glucocorticoid-induced kinase 1 (SGK1) is an enzyme that may play a vital role in myocardial ischemia/reperfusion (I/R) injury. This enzyme may affect sarcoplasmic reticulum Ca2+ ATPase (SERCA2), ryanodine receptor (RyR2) and sodium/calcium exchanger (NCX1) during myocardial ischemia/reperfusion injury. The objective of this investigation was to analyze the effects of the combination of GSK650394 (SGK1 inhibitor) and gallic acid on the calcium ions regulation, inflammation, and cardiac dysfunction resulting from ischemia/reperfusion (I/R) injury in the heart. Sixty male Wistar rats were randomly divided into six groups, pretreated with gallic acid or vehicle for 10 days. Then the heart was isolated and exposed to I/R. In the SGK1 inhibitor groups, GSK650394 was infused 5 min before ischemia induction. After that, Ca2+ homeostasis, inflammatory factors, cardiac function, antioxidant activity, and myocardial damage were evaluated. The findings suggested that the use of two drugs in combination therapy produced more significant improvements in left ventricular end diastolic pressure, left ventricular systolic pressure, RR-interval, ST-elevation, inflammation factors, and antioxidant enzymes activity as compared to the use of each drug. Despite this, there was a significant decrease observed in heart marker enzymes (including lactate dehydrogenase (LDH), troponin-I (cTn-I), creatine kinase-MB (CK-MB) and creatine phosphokinase (CPK) when compared to the ischemic group. Additionally, the expression of RyR2, NCX1, and SERCA2 genes showed a noteworthy increase as compared to the ischemic group. The findings of this study propose that using both of these agents on myocardial I/R injury could have superior advantages compared to using only one of them.

Velvet antler polypeptide (VAP) protects against cerebral ischemic injury through NF-κB signaling pathway in vitro

OBJECTIVE

Velvet antler polypeptide (VAP) has been shown to play important roles in the immune and nervous systems. The purpose of this study was to investigate the protective effects of VAP on cerebral ischemic injury with the involvement of NF-κB signaling pathway in vitro.

MATERIALS AND METHODS

PC-12 cells stimulated by oxygen-glucose deprivation/reperfusion (OGD/R) was used to mimic cerebral ischemic injury in vitro. The levels of ROS, SOD, and intracellular concentrations of Ca2+ were measured by the relevant kits. Meanwhile, the expressions of inflammatory cytokines (IL-6, IL-1β, and TNF-α) were determined by ELISA kit assay. In addition, MTT, EdU, and flow cytometry assays were used to measure the cell proliferation and apoptosis. Besides which, the related proteins of NF-κB signaling pathway were measured by western blotting assay.

RESULTS

VAP alleviated cerebral ischemic injury by reducing OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells in a time dependent manner. Mechanistically, VAP inhibited the levels of p-p65 and p-IkB-α in a time dependent manner, which was induced by OGD/R operation. Moreover, NF-κB agonist diprovocim overturned the suppression effects of VAP on OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells.

CONCLUSIONS

The results demonstrate that VAP may alleviate cerebral ischemic injury by suppressing the activation of NF-κB signaling pathway.

Bioinformatics analysis and experimental validation revealed that Paeoniflorigenone effectively mitigates cerebral ischemic stroke by suppressing oxidative stress and inflammation

Inflammation and oxidative stress are becoming more recognized as risk factors for ischemic stroke. Paeoniflorigenone (PA) has diverse pharmacological effects that include anti-inflammatory and antioxidant properties. However, the specific mechanisms by which PA affects cerebral ischemic stroke have not been studied. Our objective was to investigate the potential targets and mechanisms of PA in preventing cerebral ischemic stroke. We obtained the potential targets of PA from the SwissTargetPrediction, Super-PRED, and SEA Search Server databases. The GSE97537 dataset was utilized to identify gene targets related to ischemic stroke. The overlapping targets were imported into the STRING database to construct a protein-protein interaction network, and enrichment analyses were conducted using R software. Rats were pretreated with PA for three weeks before undergoing MCAO and reperfusion. H&E staining, ELISA, and qRT-PCR analyses were then performed to explore the potential mechanisms of PA. In the study, we identified 439 potential targets for PA and 1206 potential targets for ischemic stroke. Out of these, there were 71 common targets, which were found to be primarily associated with pathways related to oxidative stress and inflammation. The results from animal experiments showed that PA was able to improve nerve function and reduce inflammatory cytokines and oxidative stress in the MCAO-induced ischemic stroke model. Additionally, the expression of core genes in the MCAO + HPA group was significantly lower compared to the MCAO group. Our study revealed that the potential mechanisms by which PA prevents ischemic stroke involve oxidative stress and inflammation. These findings provide important theoretical guidance for the clinical use of PA in preventing and managing ischemic stroke.

Human amniotic mesenchymal stem cell-conditioned medium inhibited LPS-induced cell injury and inflammation by modulating CD14/TLR4-mediated signaling pathway in monocytes

Human amniotic mesenchymal stem cells (hAMSCs) have attracted considerable attention as a promising regenerative therapy. Many studies reported that the conditioned medium of hAMSCs (AM-CM) exerted anti-inflammatory and immunomodulatory functions, while its underlying mechanism is poorly understood. In this study, we first confirmed that AM-CM (25%, 50%, 100%) was optimal for anti-inflammation at 24 h. Lipopolysaccharide (LPS)-induced alteration of cell morphology, the decrease of cell proliferation, and the upregulation of cell apoptosis were significantly reversed in AM-CM-treated THP-1 cells. 25% and 50% AM-CM significantly decreased LPS-induced intracellular reactive oxygen species (ROS) production and proinflammatory cytokines secretion. Mechanistically, we found that AM-CM treatment suppressed LPS-induced activation of MAPK and NF-κB pathways by inhibiting CD14/TLR4 in THP-1 cells. Meanwhile, activation of NLRP3 inflammasome was also dose-dependently attenuated by AM-CM treatment. Thus, AM-CM may exert positive influences on the inflammation microenvironment and provide a novel strategy for improving tissue regeneration.

Tongqiao Huoxue decoction alleviates neurological impairment following ischemic stroke via the PTGS2/NF-kappa B axis

Traditional Chinese medicine has emerged as promising targets for ischemic stroke (IS) therapy, yet the mechanism remains elusive. The current study was performed with an aim to investigate the action and mechanism of Tongqiao Huoxue decoction (TQHXD) affecting the neurological impairment secondary to IS based on network pharmacology. Based on network pharmacology and bioinformatics analysis, target genes and pathways involved in the treatment of TQHXD against IS were predicted. Serum containing TQHXD was prepared through blood collection from C57BL/6 mice after intragastric administration of TQHXD. The main results exhibited that Prostaglandin-endoperoxide synthase 2 (PTGS2) exhibited an abundance in IS and enrichment in the NF-kappa B signaling pathway, holding the potential as targets related to TQHXD treatment for IS. TQHXD was found to rescue cell viability, inhibit apoptosis, and alleviate inflammation under oxygen and glucose deprivation and reoxygenation (OGD/R) exposure. Furthermore, our in vivo experiment validated the protective function of TQHXD in ischemic brain damage stimulated by middle cerebral artery occlusion (MCAO). This protective action of TQHXD could be attenuated by overexpressing nuclear factor (NF)-kappa B, which was dependent on PTGS2. Collectively, TQHXD was demonstrated to ameliorate IS-induced neurological impairment by blocking the NF-kappa B signaling pathway and down-regulating PTGS2.

Exosomal ZEB1 Derived from Neural Stem Cells Reduces Inflammation Injury in OGD/R-Treated Microglia via the GPR30-TLR4-NF-κB Axis

Ischemic stroke (IS) is the most common type of stroke and the second leading cause of death overall. Neural stem cells play protective roles in IS, but the underlying mechanism remains to be determined. Neural stem cells (NSC) were obtained from the fetal brain tissue of C57BL/6J mice. NSC-derived exosomes (NSC-Exos) were identified in the conditioned medium. Internalization of NSC-Exos was analyzed by fluorescence microscopy. In vitro microglia ischemic stroke injury model was induced using oxygen glucose deprivation/re-oxygenation (OGD/R) method. Cell viability and inflammation were analyzed by MTT, qPCR, ELISA and Western blotting assay. Interaction between ZEB1 and the promoter of GPR30 was verified by luciferase assay and chromatin immunoprecipitation. NSC-Exos prevented OGD/R-mediated inhibition of cell survival and the production of inflammatory cytokines in microglia cells. NSC-Exos increased ZEB1 expression in OGD/R-treated microglia. Down-regulation of ZEB1 expression in NSC-Exos abolished NSC-Exos' protective effects on OGD/R-treated microglia. ZEB1 bound to the promoter region of GPR30 and promoted its expression. Inhibiting GPR30 reversed NSC-Exos effects on cell viability and inflammation injury in OGD/R-treated microglia. Our study demonstrated that NSC exerted cytoprotective roles through release of exosomal ZEB1,which transcriptionally upregulated GPR30 expression, resulting in a reduction in TLR4/NF-κB pathway-induced inflammation. These findings shed light on NSC-Exos' cytoprotective mechanism and highlighted its potential application in the treatment of IS.

Storax Protected Primary Cortical Neurons from Oxygen-Glucose Deprivation/Reoxygenation Injury via Inhibiting the TLR4/TRAF6/NF-κB Signaling Pathway

Storax is a traditional Chinese herb that is widely applied in stroke treatment. However, its neuroprotective effects and mechanisms are yet to be fully elucidated. This study aimed to elucidate the neuroprotective effects and underlying mechanisms of storax on oxygen-glucose deprivation/reoxygenation (OGD/R) in injured cortical neurons. The cortical neurons of Wistar rats were primarily cultured in vitro. TheTUNELmethod and CM-H2DCFDA probe were used to detect cell apoptosis and reactive oxygen species (ROS) expression. Enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot were used to detect the expression of inflammatory cytokines and proteins of the TLR4/TRAF6/NF-κB signaling pathway. Immunofluorescence was used to measure NF-κB nuclear translocation. Transfection of TLR4 siRNA was used to detect the potential anti-inflammatory mechanisms of storax. The present results have shown that storax protected primary cortical neurons from OGD/R-induced injury by suppressing ROS generation and cell apoptosis; alleviating HMGB-1, TNF-α, IL-1β, and ICAM-1 expression; and promoting IL-10 expression. In addition, storax inhibited the activation of TLR4, TRAF6, IκBα, IKKβ, and NF-κBp65 caused by OGD/R. It is suggested that storax prevents OGD/R-induced primary cortical neuron injury by inhibiting the TLR4/TRAF6/NF-κB signaling pathway.

Potential Anti-Inflammatory Effects of a New Lyophilized Formulation of the Conditioned Medium Derived from Periodontal Ligament Stem Cells

The mesenchymal stem cells’ (MSCs) secretome includes the bioactive molecules released in the conditioned medium (CM), such as soluble proteins, free nucleic acids, lipids and extracellular vesicles. The secretome is known to mediate some of the beneficial properties related to MSCs, such as anti-inflammatory, anti-apoptotic and regenerative capacities. In this work, we aim to evaluate the anti-inflammatory potential of a new lyophilized formulation of CM derived from human periodontal ligament stem cells (hPDLSCs). With this aim, we treat hPDLSCs with lipopolysaccharide (LPS) and test the anti-inflammatory potential of lyophilized CM (LYO) through the evaluation of wound closure, transcriptomic and immunofluorescence analysis. LPS treatment increased the expression of TLR4 and of genes involved in its signaling and in p38 and NF-κB activation, also increasing the expression of cytokines and chemokines. Interestingly, LYO downregulated the expression of genes involved in Toll-like receptor 4 (TLR-4), nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and p38 signaling. As a consequence, the genes encoding for cytokines and chemokines were also downregulated. Immunofluorescence acquisitions confirmed the downregulation of TLR-4 and NF-κB with the LYO treatment. Moreover, the LYO treatment also increased hPDLSCs’ migration. LYO was demonstrated to contain transforming growth factor (TGF)-β3 and vascular endothelial growth factor (VEGF). These results suggest that LYO represents an efficacious formulation with anti-inflammatory potential and highlights lyophilization as a valid method to produce stable formulations of MSCs’ secretome.

Apelin-13 attenuates injury following ischemic stroke by targeting matrix metalloproteinases (MMP), endothelin- B receptor, occludin/claudin-5 and oxidative stress

Oxidative stress, an adverse consequence of brain ischemia-reperfusion injury (IRI), activates matrix metalloproteinase enzymes which cause to destruction of extracellular matrix and tight junction proteins. Oxidative stress during stroke increases serum endothelin-1 and endothelin B receptor (ETBR) expression. Apelin-13, an endogenous peptide, is expressed in numerous tissues that regulate diverse physiological and pathological processes. This study aimed to investigate the effect of intravenous (IV) injection of apelin-13 on cerebral vasogenic edema due to brain IRI. Animals were divided into sham, ischemia, and treat groups. IRI model was induced by middle cerebral artery occlusion (MCAO) for 60 min followed by 23 h reperfusion. Apelin-13 was injected into the tail vein 5 min before reperfusion. Neurological defects were evaluated with longa test. Brain water content and BBB permeability were assessed according to cerebral dry-wet weight and brain Evans blue extraction. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) were measured using the colorimetric method. Expression of occludin and claudin-5, matrix metalloproteinase- 2 and 9 (MMP-2 & 9) and, ETBR were evaluated using Western blot. Brain IRI was associated with BBB breakdowns and vasogenic edema. Apelin-13 significantly reduced BBB permeability and vasogenic edema. Apelin-13 significantly attenuated IRI-related oxidative stress. Apelin-13 decreased expression of mmp-2, 9 and ETBR, prevented from decrement of occludin and claudin-5 expersion, which protected BBB integrity and reduced vasogenic edema. In conclusion, our results have suggested that an IV injection of apelin-13 could somehow reduce vasogenic edema via targeting oxidative stress and ETBR expression.