Objectives Arterial wall inflammation and remodelling are the characteristic features of Takayasu’s arteritis (TAK). It has been proposed that vascular smooth muscle cells (VSMCs) are the main targeted cells of inflammatory damage and participate in arterial remodelling in TAK. Whether VSMCs are actively involved in arterial wall inflammation has not been elucidated. Studies have shown that cellular senescence in tissue is closely related to local inflammation persistence. We aimed to investigate whether VSMCs senescence contributes to vascular inflammation and the prosenescent factors in TAK. Methods VSMCs senescence and senescence-associated secretory phenotype were detected by histological examination, bulk RNA-Seq and single-cell RNA-seq conducted on vascular surgery samples of TAK patients. The key prosenescent factors and the downstream signalling pathway were investigated in a series of in vitro and ex vivo experiments. Results Histological findings, primary cell culture and transcriptomic analyses demonstrated that VSMCs of TAK patients had the features of premature senescence and contributed substantially to vascular inflammation by upregulating the expression of senescence-associated inflammatory cytokines. IL-6 was found to be the critical cytokine that drove VSMCs senescence and senescence-associated mitochondrial dysfunction in TAK. Mechanistically, IL-6-induced non-canonical mitochondrial localisation of phosphorylated STAT3 (Tyr705) prevented mitofusin 2 (MFN2) from proteasomal degradation, and subsequently promoted senescence-associated mitochondrial dysfunction and VSMCs senescence. Mitochondrial STAT3 or MFN2 inhibition ameliorated VSMCs senescence in ex vivo cultured arteries of TAK patients. Conclusions VSMCs present features of cellular senescence and are actively involved in vascular inflammation in TAK. Vascular IL-6-mitochondrial STAT3-MFN2 signalling is an important driver of VSMCs senescence.

Atherosclerosis is a chronic, progressive vascular disease. The relationship between CASP1 gene expression and atherosclerosis remains unclear. The atherosclerosis dataset GSE132651 and GSE202625 profiles were downloaded from gene expression omnibus. Differentially expressed genes (DEGs) were screened. The construction and analysis of protein–protein interaction network, functional enrichment analysis, gene set enrichment analysis, and Comparative Toxicogenomics Database analysis were performed. Gene expression heatmap was drawn. TargetScan was used to screen miRNAs that regulate central DEG. 47 DEGs were identified. According to gene ontology analysis, they were mainly enriched in the regulation of stimulus response, response to organic matter, extracellular region, extracellular region, and the same protein binding. Kyoto Encyclopedia of Gene and Genome analysis results showed that the target cells were mainly enriched in the PI3K-Akt signaling pathway, Ras signaling pathway, and PPAR signaling pathway. In the enrichment project of Metascape, vascular development, regulation of body fluid levels, and positive regulation of cell motility can be seen in the gene ontology enrichment project. Eleven core genes (CASP1, NLRP3, MRC1, IRS1, PPARG, APOE, IL13, FGF2, CCR2, ICAM1, HIF1A) were obtained. IRS1, PPARG, APOE, FGF2, CCR2, and HIF1A genes are identified as core genes. Gene expression heatmap showed that CASP1 was highly expressed in atherosclerosis samples and low expressed in normal samples. NLRP3, MRC1, IRS1, PPARG, APOE, IL13, FGF2, CCR2, ICAM1, HIF1A were low expressed in atherosclerosis samples. CTD analysis showed that 5 genes (CASP1, NLRP3, CCR2, ICAM1, HIF1A) were found to be associated with pneumonia, inflammation, cardiac enlargement, and tumor invasiveness. CASP1 gene is highly expressed in atherosclerosis. The higher the CASP1 gene, the worse the prognosis.

Our previous work identified several differentially expressed miRNAs (DEmiRNAs) in plasma exosomes from Takayasu’s arteritis (TAK) patients. This study aimed to validate these findings and explore the correlation between DEmiRNAs and clinical parameters in untreated TAK. Plasma exosomes were isolated from 30 untreated TAK patients and 20 healthy controls. qPCR was used to quantify miR-34a-5p, miR-143-3p, miR-22-3p, miR-200c-3p, and miR-21-5p expression. Correlations between miRNA levels, clinical data, inflammation markers, and T helper cell frequencies were analyzed. The target genes of validated DEmiRNAs were identified using mirDIP, and pathway enrichment analysis was performed using GO/KEGG. The effect of validated DEmiRNAs on the MAPK pathway and proliferation in human aortic endothelial cells (HAECs) was investigated in vitro. Only miR-200c-3p expression was validated as significantly downregulated in plasma exosomes from untreated TAK patients. Lower miR-200c-3p levels correlated negatively with ITAS-2010 scores and were associated with relapsed disease. MiR-200c-3p levels also negatively correlated with circulating Th17.1 cell frequencies. In vitro, the TAK exosome treatment activated ERK1/2 and JNK pathways and promoted HAEC proliferation, which was inhibited by the miR-200c-3p mimic. The pathway enrichment analysis showed that the MAPK pathway may be involved. This study confirms the reduced miR-200c-3p expression in plasma exosomes from TAK patients, suggesting its potential as a biomarker for vascular inflammation. MiR-200c-3p may exert protective effects in TAK by suppressing MAPK pathway activation and EC proliferation.

Objective: Although Takayasu arteritis (TAK) is not a prototypical autoantibody‐mediated disease, accumulating evidence suggests that B cells are involved. This study aimed to investigate the pathway of B cell activation and its contributions to TAK pathogenesis. Methods: Histologic analysis of paravascular lymph nodes and affected arteries was conducted to investigate B cell activation pathways in TAK. Bulk RNA‐seq, single‐cell RNA‐seq (scRNA‐seq), flow cytometry, and in vitro experiments were performed to characterize the composition, transcriptomic features, and functional profiles of B cells. The numeric and phenotypic alterations induced by tumor necrosis factor (TNF) and JAK inhibition were assessed both in vitro and in four patients with TAK. Results: Histologic (n = 5), flow cytometric (n = 125), and bulk RNA‐seq (n = 12) analyses indicated the presence of extrafollicular response and up‐regulated age‐associated B cell (ABC) production in TAK, along with cross‐data set transcriptomic differences between B cells from patients with TAK and systemic lupus erythematosus (SLE). Cross‐data set scRNA‐seq analysis and in vitro experiments (n = 5) demonstrated that ABC differentiation in TAK was largely uncoupled from antibody‐secreting cell (ASC) generation, unlike that in SLE. Functional experiments showed that ABCs exhibited proinflammatory properties, including proinflammatory cytokine production, and that CD11c ⁺ B cells, which contain the ABC compartment, promoted Th17 cell differentiation (n = 6). In vitro, tofacitinib was more effective than adalimumab at reducing ABC proportions and attenuating their proinflammatory phenotype (n = 15), consistent with trends in the exploratory clinical follow‐up (n = 4). Conclusion: ABCs promote inflammation through proinflammatory functions independent of ASC differentiation in TAK. JAK inhibition exerts distinct suppressive effects on ABCs compared with anti‐TNF therapy. image