Inflammation最新文献

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising immunomodulatory properties; however, strategies to enhance their therapeutic potential remain limited. Here, we employed CRISPR activation of the gene TSG-6 in MSCs to evaluate the impact of elevated TSG-6 on EV cargo and immunomodulatory function in an in vitro macrophage model. CRISPR-mediated gene activation was confirmed by RT-qPCR, demonstrating more than an 1800 fold increase in TSG-6 mRNA compared to controls. EVs were isolated from TSG-6 overexpressing MSCs and thoroughly characterized by nanoparticle tracking analysis, transmission electron microscopy, and Western blot, confirming their typical size distribution, morphology, and surface markers. Small RNA sequencing of these EVs revealed 15 differentially expressed miRNAs relative to EVs from control MSCs. When THP-1-derived macrophages were stimulated with LPS and treated with TSG-6-overexpressing MSC-EVs (Standard dosage: 1000 particle/cell, n = 11; Alternative dosages: 500, 1000, or 2000 particles/cell, n = 6), a marked reduction in pro-inflammatory cytokine gene expression (IL-1β, CCL2, CXCL10, and TNF-α) and secreted protein levels (CCL2, TNF-α, CXCL1, and MIP-3α) was observed. Taken together, these findings demonstrate that CRISPR-based TSG-6 activation reprograms MSC-EV miRNA cargo (as well as their protein cargo, as previously shown), which can boost their anti-inflammatory effects. These findings underscore the promise of CRISPR-activation as a novel platform for boosting the bioactive properties of MSC-EVs and enhancing immunotherapeutic efficacy.

This study aims to elucidate the mechanism by which Heat Shock Protein 60 (HSP60) mediates microglial pyroptosis in the context of early brain injury (EBI) following subarachnoid hemorrhage (SAH), and to investigate the effects of HSP60 inhibition on EBI after SAH. A mouse subarachnoid hemorrhage (SAH) model was established using prechiasmatic cistern blood injection. In vitro, microglia were stimulated with 25 µmol/L oxyhemoglobin (OxyHB) to simulate the SAH pathological environment. In vivo, mice received 100 mg/kg Mizoribine, while in vitro, 80 µmol/L Mizoribine was used to suppress SAH-induced HSP60 upregulation. Techniques including Western blotting, immunofluorescence, immunohistochemistry, transmission electron microscopy, ELISA, modified Garcia neurological scoring, beam walking, brain water content measurement, Morris water maze, TUNEL staining, and Nissl staining were employed to systematically investigate the role of HSP60 inhibition in neuroinflammation and microglial pyroptosis after SAH. Compared to the sham group, both in vivo and in vitro studies with blinded, random sampling of six groups demonstrated a significant increase in HSP60 expression post-SAH. In vivo, 100 mg/kg Mizoribine alleviated blood-brain barrier disruption, cerebral edema, neuronal apoptosis/necrosis, and improved neurological deficits and cognitive impairment. In vitro, 80 µmol/L Mizoribine markedly attenuated microglial activation and pyroptosis, downregulated pro-inflammatory cytokines, and mitigated neuroinflammation. The upregulation of HSP60 after SAH promotes NLRP3 inflammasome assembly by activating the TLR4/MyD88/NF-κB signaling pathway, thereby inducing microglial pyroptosis and exacerbating the progression of early brain injury. Inhibition of HSP60 represents a potential therapeutic strategy for ameliorating EBI after SAH.

Microglial pyroptosis-mediated neuroinflammation emerges as a critical pathogenic mechanism underlying sepsis-associated encephalopathy (SAE). Epigenetic modifications, especially histone acetylation states, exert fundamental regulatory effects on microglial pyroptosis. Among these, histone deacetylase 3 (HDAC3) has been identified as a central epigenetic regulator orchestrating these processes. This study investigates the functional role of HDAC3 in microglial pyroptosis and its underlying mechanisms contributing to SAE-related cognitive impairment. To explore this, male C57BL/6 mice subjected to cecal ligation and puncture (CLP) served as the SAE model. We employed RGFP966, a selective HDAC3 inhibitor, administered at 20 mg/kg/day via daily subcutaneous injections for 14 days starting 2 h prior to CLP surgery. To specifically examine HDAC3's role in microglia, we bilaterally injected recombinant adeno-associated virus (rAAV)-expressing rEGFP under the control of a DIO promoter into the hippocampus of Cx3cr1-Cre mice to achieve selective overexpression. Our data demonstrate that HDAC3 in microglia activates pyroptosis through the STING/NLRP3 pathway, exacerbating oxidative stress responses and impairing neural activity, ultimately leading to cognitive deficits in SAE. Furthermore, HDAC3 overexpression in microglia recapitulates these pathological changes, underscoring its central role in driving disease progression. Conversely, RGFP966 treatment effectively attenuates these abnormalities by suppressing HDAC3 expression and downstream inflammatory pathways. These findings highlight the therapeutic potential of targeting microglial HDAC3 to mitigate neuroinflammation and cognitive dysfunction in SAE, offering a novel direction for future clinical applications.

Hypothalamic inflammation plays a key pathophysiological mechanism linking chronic consumption of a high fat diet (HFD) to the development of obesity and associated metabolic complications. Pilot studies report that oral glutamine (Gln) supplementation might reduce waist circumference and improve metabolic and inflammatory status in obesity patients. Although Gln metabolism plays a key role in intercellular communication in the central nervous system, its potential beneficial effects remain unexplored in these contexts. Here, we aimed to evaluate how stress and glutamine supplementation can modulate the hypothalamic response to HFD in mice using a chronic-restraint stress (CRS) model, which mimics IBS symptoms. From week 12 to week 14, mice received or not Gln diluted in drinking water (2 g/kg/day) and were placed in restraint tubes (2 h/day) for the last four consecutive days of protocol. Male and female obese mice showed a difference in vulnerability to CRS-induced effects. Moreover, mice responded to Gln supplementation in a sex-dependent manner, especially in stress conditions. Hypothalamic pathways regulating energy homeostasis were more impacted in male mice, whereas factors involved in neuroinflammation were more affected in female mice. Gln supplementation led to an increase in Mc4r and Bdnf mRNA levels and GFAP expression in male mice, while upregulated Iba1 and Il6 mRNA levels as well as signs of microgliosis were observed in stressed females. In conclusion, mice with obesity showed sex-specific hypothalamic response to glutamine supplementation and stress. Further investigations should be done to decipher underlying mechanisms.

Background: Sclerostin regulates bone formation via Wnt/β-catenin signaling inhibition and contributes to intestinal epithelial homeostasis. Circulating sclerostin levels are reduced in axial spondyloarthritis (axSpA) and correlate with structural damage. LRP5, a receptor inhibited by sclerostin, also controls bone formation by regulating gut-derived serotonin synthesis, indicating a hormonal link between the intestine and bone. We hypothesized that gut dysbiosis-dependent downregulation of sclerostin alters intestinal serotonin production, contributing to disease-specific gut-bone signaling in axSpA.

Methods: We quantified sclerostin and the serotonin-synthesizing enzyme TPH1 by qRT-PCR, and assessed serotonin protein levels by immunohistochemistry in ileal biopsies from treatment-naïve axSpA patients (n = 25) and healthy controls (n = 20), alongside measurement of circulating serotonin in peripheral blood platelets. We evaluated TPH1 expression in BON-1 cells following sclerostin and WNT3a treatment. Findings were validated in HLA-B27 transgenic rats, SKG mice, and Sost⁻/⁻ mice. Serotonin receptor expression in spinal entheseal cells was analyzed by RT-PCR, and LPS-induced HTR2B modulation was examined.

Results: In healthy controls, sclerostin modulated TPH1 expression and serotonin synthesis in enterochromaffin cells. In axSpA patients, intestinal sclerostin downregulation coincided with increased numbers of serotonin-positive enterochromaffin cells and elevated platelet serotonin levels. Broad-spectrum antibiotics restored intestinal sclerostin expression and normalized serotonin production in HLA-B27 transgenic rats. Sost⁻/⁻ mice exhibited increased intestinal Tph1 expression, while SKG mice showed reduced sclerostin and elevated Tph1 following curdlan-induced colitis-an effect dependent on the presence of intestinal microbiota. Human spinal entheses expressed HTR1B, HTR2A, and HTR2B, with LPS selectively inducing HTR2B expression.

Conclusions: We identify a gut microbiota-dependent sclerostin-serotonin axis that regulates serotonin production and may contribute to gut-bone pathology in axSpA. These findings reveal novel mechanisms linking gut dysbiosis to bone disease and suggest potential therapeutic targets within the gut-bone-immune axis.

As a pivotal immune checkpoint molecule, programmed death-ligand 1 (PD-L1) is anchored primarily on the membrane surface of immune cells, where it exerts immunosuppressive effects, thereby facilitating tumor immune evasion. Macrophages, which serve as essential sentinels of the innate immune system, play dual regulatory roles in inflammatory pathologies, particularly during sepsis progression. While their secreted chemokines mediate inflammatory cell recruitment for pathogen clearance, excessive chemokine production can paradoxically induce organ damage and immune cell exhaustion, necessitating precise regulatory mechanisms. Conventional understanding suggests that PD-L1 on macrophages engages with programmed cell death protein 1 (PD-1) on T lymphocytes to suppress T-cell proliferation, cytokine secretion (e.g., IFN-γ and IL-2), and cytotoxic functions, thereby negatively modulating adaptive immunity. However, emerging evidence also suggests that PD-L1 has context-dependent proinflammatory functions. Given this context, we hypothesized that macrophage-intrinsic PD-L1 plays a poorly understood role in directly regulating chemokine production during sepsis. Our integrative analysis incorporating clinical database mining and RNA sequencing (RNA-seq) revealed a less defined proinflammatory property of PD-L1 under septic conditions-an ability to increase CCL8 and CXCL9 chemokine expression in inflammatory macrophages. Through combinatorial approaches, including immunoprecipitation‒mass spectrometry (IP‒MS), molecular docking, and site-directed mutagenesis, we preliminarily elucidated that PD-L1 likely governs the chemotactic mediators CCL8 and CXCL9 via the TLR4/TRAF6 signaling axis. These findings collectively establish the previously unappreciated regulatory capacity of macrophage-intrinsic PD-L1 in chemokine modulation during sepsis, potentially informing the development of innovative therapeutic strategies targeting immune dysregulation in critical care settings.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by persistent synovial inflammation, joint destruction, and systemic complications. Recent research has revealed the complex involvement of autophagy, a cellular degradation and recycling process, in the pathogenesis and progression of RA. This review provides a comprehensive analysis of autophagy's multifaceted roles across immune regulation, synovial hyperplasia, osteoclastogenesis, and antigen presentation. Particular attention is given to the dualistic nature of autophagy, which may exert both protective and pathogenic effects depending on the cellular context and disease stage. We explore key molecular pathways regulating autophagy, including the mTOR, AMPK, and ULK1 axes, and detail how these are modulated by cytokines and signaling molecules characteristic of the RA inflammatory milieu. Epigenetic and genetic factors, including polymorphisms in ATG and BECN1 genes, microRNA regulation, and histone modifications, are also examined for their impact on autophagic flux and immune dysregulation. The diagnostic potential of autophagy-related biomarkers is discussed through transcriptomic and bioinformatics studies that stratify RA subtypes and correlate autophagic activity with disease severity. Additionally, we review therapeutic strategies targeting autophagy, encompassing conventional DMARDs, biologics, small molecules, nanoparticles, and phytochemicals. While modulating autophagy shows clinical promise, challenges remain regarding safety, specificity, and long-term efficacy. The integration of high-throughput omics technologies with artificial intelligence presents new opportunities to refine diagnostic precision and develop personalized therapeutic interventions. This review underscores the necessity of further translational research to define context-specific roles of autophagy in RA and to harness its potential in advancing precision medicine.

Free fatty acids (FFA) and lipopolysaccharide (LPS) synergistically exacerbate metabolic inflammation, but the underlying mechanisms remain unclear. This study investigates how FFA and LPS cooperatively promote macrophage M1 polarization and insulin resistance (IR). In vivo models (HFD-fed and LPS-treated mice) and in vitro macrophage assays were employed. Flow cytometry, RNA-seq, m6A methylation analysis, and AAV-mediated gene modulation of FTO or CSF1 were used to dissect mechanisms. Metabolic phenotypes in mice were assessed via fasting blood glucose and HOMA-IR index. Combined FFA and LPS treatment synergistically increased M1 macrophage polarization and IR, correlating with elevated FTO expression. FTO upregulated by FFA/LPS reduced m6A modification of CSF1 mRNA, promoting its degradation via impaired IGF2BP2 binding. Depleting FTO or restoring CSF1 attenuated M1 polarization and improved insulin sensitivity in vivo. The FTO-m6A-CSF1 axis drives FFA/LPS-induced metabolic inflammation, offering therapeutic targets for IR.

Ischemic stroke triggers detrimental neuroinflammatory responses where astrocytes play a pivotal role. This study investigates whether Sirtuin 3 (SIRT3), a key cellular regulator, mitigates astrocyte-mediated neuroinflammation by modulating the cGAS-STING pathway. Using in vivo ischemic stroke models and in vitro astrocyte cultures subjected to ischemic-like injury, we demonstrate that SIRT3 expression is significantly suppressed post-injury, coinciding with pronounced activation of the cGAS-STING signaling cascade and elevated release of pro-inflammatory cytokines. Pharmacological activation of SIRT3 or its genetic overexpression effectively reduced cerebral damage, improved neurological outcomes, and suppressed cGAS-STING pathway activation. Conversely, targeted knockdown of cGAS or STING similarly attenuated inflammatory responses. Transcriptomic analysis revealed that SIRT3 overexpression alters genes associated with DNA sensing and innate immune pathways. These findings establish that SIRT3 alleviates post-stroke neuroinflammation in astrocytes by inhibiting the cGAS-STING pathway, highlighting SIRT3 as a promising therapeutic target for ischemic stroke treatment.

Indole-3-aldehyde (IAld), an indole derivative of tryptophan metabolized by microorganisms, has been observed to improve epithelial barriers in multiple chronic inflammatory diseases through the aryl hydrocarbon receptor (AhR). This study aimed to elucidate the role and underlying mechanism of IAld in preserving the gingival epithelium via AhR activation in periodontitis. An experimental mouse model of periodontitis was established to assess the anti-periodontitis effect of IAld by using micro-computed tomography (Micro-CT), hematoxylin-eosin staining, immunohistochemical staining and 16S rRNA amplicon sequencing. Subsequently, CCK-8 assays, FITC-FD4 flux measurements, western blotting, and immunofluorescence staining were performed to confirm the protective effect of IAld on P. gingivalis-treated human gingival epithelial cells (hGECs) in vitro. Finally, RNA sequencing, immunofluorescence and immunohistochemical staining were used to thoroughly explore the underlying mechanism. We observed that in periodontitis mice, IAld treatment inhibited alveolar bone loss and periodontal tissue inflammation; activated the AhR pathway; increased the expression levels of E-cadherin, Claudin1, Occludin and ZO-1; and reshaped the oral microbial composition. In vitro, P. gingivalis-stimulated hGECs treated with IAld exhibited decreased FITC-FD4 permeability and upregulated expression of CYP1A1, E-cadherin and Claudin1 compared to the P. gingivalis group. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses revealed downregulation of oxidative stress pathways and overexpression of the antioxidants NrF2 and Hmox1. In vitro, IAld treatment reduced reactive oxygen species (ROS) production and upregulated the expression of Nrf2 and HO-1. Overall, our study demonstrated that IAld improved the function and integrity of the gingival epithelial barrier via the AhR/Nrf2 signaling pathway, thus providing a potential strategy for periodontitis treatment.