Mesenchymal stem cells (MSCs) have demonstrated potent immunomodulatory properties that have shown promise in the treatment of autoimmune diseases, including rheumatoid arthritis (RA). However, the inherent heterogeneity of MSCs triggered conflicting therapeutic outcomes, raising safety concerns and limiting their clinical application. This study aimed to investigate the potential of extracellular vesicles derived from human gingival mesenchymal stem cells (GMSC-EVs) as a therapeutic strategy for RA. Through in vivo experiments using an experimental RA model, our results demonstrate that GMSC-EVs selectively homed to inflamed joints and recovered Treg and Th17 cell balance, resulting in the reduction of arthritis progression. Our investigations also uncovered miR-148a-3p as a critical contributor to the Treg/Th17 balance modulation via IKKB/NF-κB signaling orchestrated by GMSC-EVs, which was subsequently validated in a model of human xenograft versus host disease (xGvHD). Furthermore, we successfully developed a humanized animal model by utilizing synovial fibroblasts obtained from patients with RA (RASFs). We found that GMSC-EVs impeded the invasiveness of RASFs and minimized cartilage destruction, indicating their potential therapeutic efficacy in the context of patients with RA. Overall, the unique characteristics — including reduced immunogenicity, simplified administration, and inherent ability to target inflamed tissues — position GMSC-EVs as a viable alternative for RA and other autoimmune diseases.

T follicular helper (Tfh) cells represent an important subset of CD4 ⁺ T cells that is crucial to the maturation and differentiation of B cells and the production of high-affinity antibodies. Because B cell activating–factor (BAFF), a vital B cell survival factor, is also crucial to B cell maturation and differentiation, we assessed the effects of BAFF on Tfh cell development and function. We demonstrated that deficiency of BAFF, but not of APRIL, markedly inhibited Tfh cell development, germinal center (GC) formation, and antigen-specific antibody production. The promoting effect of BAFF on Tfh cell development was dependent on expression of BR3 on T cells, and its promoting effect on GC formation was dependent on expression of BR3 on both T cells and B cells. BAFF directly promoted expression of the Tfh cell–characteristic genes via NF-κB signaling. This effect did need BR3 expression. Thus, BAFF not only has direct effects on B cells, but it also has direct effects on Tfh cell differentiation via engagement of BR3, which collectively promoted GC formation and production of high-affinity antibodies. This dual effect of BAFF on B cells and Tfh cells may help explain the clinical utility of BAFF antagonists in the management of certain autoimmune diseases.

Cardiac endogenous senescence will gradually change and aggravate with age. Recent research showed that 17β-estradiol (17β-E2), an estrogen with numerous biological activities including the prevention of vascular senescence. However, how 17β-E2 against cardiac aging is still unknown. This work addressed the underlying mechanism with regard to Beclin1 and autophagy activity to better understand the anti-senescent effect of 17β-E2 on a well-established animal model of cardiac aging. The findings demonstrated that cardiac aging mice treated with 17β-E2 had substantially improved heart function. By RNA-sequencing and Gene Set Enrichment Analysis (GSEA) analysis, the autophagy signaling pathway was further enriched in the myocardial tissue of cardiac aging mice treated with 17β-E2, and we also discovered that 17β-E2 obviously suppress the methylation of Beclin1 promoter region, which mediate the activation of autophagy signal. Overall, our data showed that 17β-E2's anti-senescent effect on cardiac aging mice was mediated by the crucial suppression of methylation in the Beclin1 promoter area and subsequent activation of the autophagy signal, which may present a possible therapeutic approach to prevent cardiac aging.