Inhibition of TLR4 Signaling by Isorhapontigenin Targeting of the AHR Alleviates Cerebral Ischemia/Reperfusion Injury

Isorhapontigenin suppresses inflammation, proliferation and aggressiveness of rheumatoid arthritis fibroblast-like synoviocytes by targeting farnesyl diphosphate synthase

BACKGROUND

Isorhapontigenin (ISO) has been reported to exhibit various therapeutic effects including anti-inflammation and anti-cancer. However, it is still unclear whether ISO has therapeutic efficacy on rheumatoid arthritis (RA). This study aimed to determine the effects of ISO on regulating functions of RA fibroblast-like synoviocytes (FLS) and further to explore the underlying mechanisms.

METHODS

Cell viability was assessed by CCK8 kit, cell apoptosis was measured using Annexin V-APC/PI assay and cell proliferation was evaluated with EdU assay. The cell scratch assay, Transwell assay, and pseudopodia formation assay were applied to detect the migration and invasion of RA FLS. Proinflammatory cytokines and MMPs mRNA expression was analyzed using RT-qPCR, while protein expression was examined by western blotting assay. Furthermore, RNA sequencing was employed to identify the potential downstream targets of ISO. Collagen-induced arthritis (CIA) mice were constructed to investigate the vivo efficacy of ISO.

RESULTS

ISO (12.5, 25, and 50 μΜ) showed inhibition of TNF-α-induced IL-6, IL-8, and MMP-3 expression, as well as proliferation, migration and invasion of RA FLS. However, it did not affect viability or apoptosis. Moreover, there were no significant difference in the efficacy on the proliferation, migration and invasion among ISO, methotrexate and dexamethasone. Mechanistically, farnesyl diphosphate synthase (FDPS) was identified as the novel target of ISO in RA FLS through RNA sequencing and Reactome enrichment analysis. FDPS expression was upregulated in FLS and synovial tissues from RA patients compared to healthy controls. Furthermore, both ISO treatment and FDPS knockdown were found to reduce TNF-α-induced activation of the AKT and ERK1/2 pathways. Interestingly, ISO treatment ameliorated synovial inflammation and joint destruction, and decreased synovial FDPS expression in CIA mice.

CONCLUSION

ISO treatment may attenuate the pathological behaviours of RA FLS by targeting FDPS-mediated phosphorylation of AKT and ERK1/2 pathways. Our data suggest that ISO might be a novel potential agent for RA treatment.

Identification of novel inflammatory response-related biomarkers in patients with ischemic stroke based on WGCNA and machine learning

BACKGROUND

Ischemic stroke (IS) is one of the most common causes of disability in adults worldwide. This study aimed to identify key genes related to the inflammatory response to provide insights into the mechanisms and management of IS.

METHODS

Transcriptomic data for IS were downloaded from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were used to identify inflammation-related genes (IRGs) associated with IS. Hub IRGs were screened using Lasso, SVM-RFE, and random forest algorithms, and a nomogram diagnostic model was constructed. The diagnostic performance of the model was assessed using receiver operating characteristic (ROC) curves and calibration plots. Additionally, immune cell infiltration and potential small molecule drugs targeting IRGs were analyzed. The expression of IRG was verified by qRT-PCR in healthy controls and IS patients.

RESULTS

Nine differentially expressed IRGs were identified in IS, including NMUR1, AHR, CD68, OSM, CDKN1A, RGS1, BTG2, ATP2C1, and TLR3. Machine learning algorithms selected three hub IRGs (AHR, OSM, and NMUR1). A diagnostic model based on these three genes showed excellent diagnostic performance for IS, with an area under the curve (AUC) greater than 0.9 in both the training and validation sets. Immune infiltration analysis revealed higher levels of neutrophils and activated CD4 + T cells, and lower levels of CD8 + T cells, activated NK cells, and naive B cells in IS patients. The hub IRGs exhibited significant correlations with immune cell infiltration. Furthermore, small molecule drugs targeting hub IRGs were identified, including chrysin, piperine, genistein, and resveratrol, which have potential therapeutic effects for IS. qRT-PCR evaluation demonstrated that the levels of blood biomarkers (AHR, OSM, and NMUR1) in IS patients could serve as distinguishing indicators between IS patients and healthy controls (P < 0.05).

CONCLUSION

This study confirmed the significant impact of IRGs on the progression of IS and provided new diagnostic and therapeutic targets for personalized treatment of IS.

Binding of ligands to the aryl hydrocarbon receptor: An overview of methods

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, which plays numerous and pivotal roles in human physiology and pathophysiology. Therefore, pharmacotherapeutic targeting of the AhR is a highly pertinent issue. The identification of new AhR ligands and the characterization of the interactions between the AhR ligands and AhR protein requires appropriate methodology. In spite the AhR is monomeric intracellular soluble receptor, the full-length human AhR protein has not been crystallized so far, and its isolation in a form applicable in the binding assays is highly challenging. Recent advances, including crystallization of AhR fragments, recombinant protein technologies, and cryogenic electron microscopy, allowed for exploitation of diverse experimental techniques for studying interactions between ligands and the AhR. In the current paper, we review existing AhR ligand binding assays, including their description, applicability and limitations.

Gnetupendin A protects against ischemic stroke through activating the PI3K/AKT/mTOR-dependent autophagy pathway

BACKGROUND

Autophagy has been recently emerged as a prominent factor in the pathogenesis of ischemic stroke (IS) and is increasingly being considered as a potential therapeutic target for IS. Gnetum parvifolium has been identified as a potential therapeutic agent for inflammatory diseases such as rheumatism and traumatic injuries. However, the pharmacological effects of Gnetupindin A (GA), a stilbene compound isolated from Gnetum parvifolium, have not been fully elucidated until now.

OBJECTIVE

Here we identified the therapeutic potential of GA for IS, deeply exploring the possible mechanisms related to its regulation of autophagy.

METHODS

The mouse model of middle cerebral artery occlusion-reperfusion (MCAO/R) and the oxygen-glucose deprivation reperfusion (OGD/R)-exposed cells served as models to study the protection of GA against IS. The adeno-associated virus (AAV) encoding shAtg5, in conjunction with autophagy inhibitor 3-Methyladenine (3-MA) were utilized to explore the role of GA in regulating autophagy following IS. Molecular docking, CETSA, and DARTS were used to identify the specific therapeutic target of GA. PI3K inhibitor LY294002 was employed to test the participation of PI3K in GA-mediated autophagy and neuroprotective effects following IS.

RESULTS

Our findings revealed that treatment with GA significantly alleviated the brain infract volume, edema, improved neurological deficits and attenuated apoptosis. Mechanistically, we found that GA promoted autophagic flow both in vivo and in vitro after IS. Notably, neural-targeted knockdown of Atg5 abolished the neuroprotective effects mediated by GA. Inhibition of autophagy using 3-MA blocked the attenuation on apoptosis induced by GA. Moreover, molecular docking, CETSA, and DARTS analysis demonstrated that GA specifically targeted PI3K and further inhibited the activation of PI3K/AKT/mTOR signaling pathway. LY294002, which inhibits PI3K, reversed GA-induced autophagy and neuroprotective effects on OGD/R-treated cells.

CONCLUSION

We demonstrated, for the first time, that GA protects against IS through promoting the PI3K/AKT/mTOR-dependent autophagy pathway. Our findings provide a novel mechanistic insight into the anti-IS effect of GA in regulating autophagy.

Investigation of the molecular mechanisms underlying the anti-inflammatory and antitumour effects of isorhapontigenin: Insights from in vitro and in vivo studies

Isorhapontigenin (ISO), a naturally-occurring stilbene derivative, has garnered significant attention due to its potent anticancer and anti-inflammatory properties. This review synthesizes current knowledge regarding the mechanisms of action, efficacy, and potential therapeutic applications of Isorhapontigenin acquired in vitro and in vivo. It systematically analyzes its effects on various cancer cell lines, tumor models, and inflammatory conditions, examining its impact on cell proliferation, apoptosis, metastasis, and inflammatory mediators. In vitro studies reveal that Isorhapontigenin induces cell cycle arrest, promotes apoptosis, and inhibits cancer cell migration through modulation of key signaling pathways, including EGFR-PI3K-Akt and NF-κB. It also demonstrates potent antioxidant and anti-inflammatory effects by enhancing Nrf2 signaling and suppressing pro-inflammatory cytokine production. These findings are corroborated by in vivo studies confirming its ability to inhibit tumor growth in xenograft models and attenuate inflammatory responses in various disease models. Notably, Isorhapontigenin exhibits superior pharmacokinetic profiles then resveratrol, with higher oral bioavailability. Isorhapontigenin demonstrates multi-target actions, including epigenetic modulation through microRNA regulation, which highlight its potential as a versatile therapeutic agent. This review also identifies current limitations in Isorhapontigenin research that require further investigation. Overall, Isorhapontigenin offers promise as a multi-faceted compound for the treatment of cancer, inflammatory diseases, and metabolic disorders, providing a solid foundation for future research and potential clinical applications.

A quinolinyl resveratrol derivative alleviates acute ischemic stroke injury by promoting mitophagy for neuroprotection via targeting CK2α'

Ischemic stroke (IS) is a serious threat to human health. The naturally derived small molecule (E)-5-(2-(quinolin-4-yl) ethenyl) benzene-1,3-diol (RV01) is a quinolinyl analog of resveratrol with great potential in the treatment of IS. The aim of this study was to investigate the potential mechanisms and targets for the protective effect of the RV01 on IS. The mouse middle cerebral artery occlusion and reperfusion (MCAO/R) and oxygen-glucose deprivation and reperfusion (OGD/R) models were employed to evaluate the effects of RV01 on ischemic injury and neuroprotection. RV01 was found to significantly increase the survival of SH-SY5Y cells and prevent OGD/R-induced apoptosis in SH-SY5Y cells. Furthermore, RV01 reduced oxidative stress and mitochondrial damage by promoting mitophagy in OGD/R-exposed SH-SY5Y cells. Knockdown of CK2α' abolished the RV01-mediated promotion on mitophagy and alleviation on mitochondrial damage as well as neuronal injury after OGD/R. These results were further confirmed by molecular docking, drug affinity responsive target stability and cellular thermal shift assay analysis. Importantly, in vivo study showed that treatment with the CK2α' inhibitor CX-4945 abolished the RV01-mediated alleviation of cerebral infarct volume, brain edema, cerebral blood flow and neurological deficit in MCAO/R mice. These data suggest that RV01 effectively reduces damage caused by acute ischemic stroke by promoting mitophagy through its interaction with CK2α'. These findings offer valuable insights into the underlying mechanisms through which RV01 exerts its therapeutic effects on IS.

Structurally diverse stilbenes from Gnetum parvifolium and their anti-neuroinflammatory activities

Phytochemical investigation on the aerial parts of Gnetum parvifolium led to the isolation of 15 new and eight known structurally diverse stilbenes. The isolated compounds comprised (E)- or (Z)-stilbene (1-6, 15-20), dihydrostilbene (21), phenylbenzofuran (7, 8, 22), benzylated stilbene (9-11), benzylated stilbene dimer (12), and nitrogen-containing stilbene (13a, 13b, 14) types. The structures of the new compounds (1-12, 13a, 13b, 14) were established through spectroscopic analyses and experimental and calculated ECD data. Compound 12 is the first stilbene dimer connected through a benzyl group. In the anti-neuroinflammatory activity assay, compounds 4, 5, 9-11, 13b, and 16-21 displayed significant inhibitory effects against LPS-induced NO release in BV-2 microglial cells, with IC50 values of 0.35-16.1 μM. Compound 10 had the most potent activity (IC50 = 0.35 μM), and the further research indicated that it could decrease the mRNA levels of iNOS, IL-1β, IL-6, and TNF-α in a dose-dependent manner.

HuR deficiency abrogated the enhanced NLRP3 signaling in experimental ischemic stroke

Human antigen R (HuR) is a universally expressed RNA-binding protein that plays an essential role in governing the fate of mRNA transcripts. Accumulating evidence indicated that HuR is involved in the development and functions of several cell types. However, its role in cerebral ischemia/reperfusion injury (CIRI) remains unclear. In this study, we found that HuR was significantly upregulated after CIRI. Moreover, we found that silencing HuR could inhibit the inflammatory response of microglia and reduce the damage to neurons caused by oxygen-glucose deprivation/reperfusion treatment. In vivo, we found that microglial HuR deficiency significantly ameliorated CIRI and reduced NLRP3-mediated inflammasome activation. Mechanistically, we found that HuR could regulate NLRP3 mRNA stability by binding to the AU-rich element (ARE) region within the 3' untranslated region (UTR) of NLRP3 mRNA. In addition, we found that the upregulation of HuR was dependent on the upregulation of NADPH oxidase-mediated ROS accumulation. Collectively, our studies revealed that HuR could regulate NLRP3 expression and that HuR deficiency abrogated the enhanced NLRP3 signaling in experimental ischemic stroke. Targeting HuR may be a novel therapeutic strategy for cerebral ischemic stroke treatment.