Shelterin Dysfunction Promotes CD4+ T Cell Senescence in Behçet's Disease.

OBJECTIVES:To investigate the potential role of shelterin dysfunction in naïve CD4+ T cells in the pathogenesis of Behçet's disease (BD). METHODS:Naïve CD4+ T cells were isolated from 40 BD patients and 40 sex- and age-matched healthy controls (HC). Senescent profiles, shelterin subunits expression, telomere length, telomerase activity, and critical DNA damage response (DDR) was evaluated. TRF2 silencing was conducted for further validation. RESULTS:Compared to HC, BD patients had significantly decreased naïve CD4+ T cells, increased cell apoptosis, senescence, and productions of TNF-α and IFN-γ upon activation. Notably, BD naïve CD4+ T cells had shortened telomere, impaired telomerase activity, and expressed lower levels of shelterin subunits TRF2, TIN2, and RAP1. Furthermore, BD naïve CD4+ T cells exhibited significantly increased DDR, evidenced by elevated phosphorylated ataxia telangiectasia (AT) mutated (pATM), pp53, and p21. Finally, TRF2-silencing markedly upregulated DDR, apoptosis, and proinflammatory cytokines production in HC naïve CD4+ T cells. CONCLUSION:Our study demonstrated that TRF2 deficiency in BD naïve CD4+ T cells promoted cell apoptosis and senescence, leading to proinflammatory cytokines overproduction. Therefore, restoring TRF2 might be a promising therapeutic strategy for BD.