CVB3 regulates Treg cell pyroptosis through the lncRNA XIST/miR-195-5p/caspase-1 molecular axis

Viral myocarditis (VMC) is characterized by severe cardiac inflammation and is a major cause of congestive heart failure and sudden cardiac death in healthy young people. The lncRNA XIST plays an important regulatory role in myocardial injury, but its role in VMC caused by coxsackievirus B3 (CVB3) infection is unclear. In this study, we evaluated the effects of the lncRNA XIST on a CVB3-induced VMC mouse model and on pyroptosis in CVB3-exposed Treg cells. The results showed that in CVB3-infected VMC and Treg cells, the expression level of the lncRNA XIST was increased, whereas miR-195-5p expression was decreased. In CVB3-induced VMC mice, inflammation was elevated, whereas the Treg/Th17 ratio was reduced. Knocking down the lncRNA XIST suppressed pyroptosis in Treg cells caused by CVB3 infection and inhibited VMC progression in vivo. Studies on downstream mechanisms have shown that the lncRNA XIST targets miR-195-5p, induces caspase-1 expression through the inhibition of miR-195-5p, promotes the expression of the inflammatory factors IL-1β and IL-18 associated with pyroptosis, inhibits the secretion of the anti-inflammatory factors IL-10 and TGF-β1, and ultimately promotes pyroptosis in Treg cells. In conclusion, knocking down the lncRNA XIST inhibits CVB3-induced pyroptosis of Treg cells and VMC progression in mice induced by CVB3 infection. These findings provide a potential theoretical basis for the treatment of VMC.