sRAGE inhibits myocardial ischemia/reperfusion injuries via regulating Treg cells.

BACKGROUND: Regulatory T cells (Tregs) have been documented to accumulate in damaged myocardial tissue, where they play a pivotal role in attenuating excessive inflammatory responses during myocardial ischemia/reperfusion (I/R) injury. Concurrently, soluble receptor for advanced glycation end-products (sRAGE) has been demonstrated to alleviate myocardial I/R injury by suppressing inflammation, suggesting a potential involvement of Tregs in the inhibitory effects of sRAGE on myocardial I/R injury. METHODS: I/R surgery or glucose deprivation/reoxygenation was employed to explore myocardial injury and the related mechanisms by using cardiomyocyte-specific sRAGE knock-in mice or cultured cardiomyocytes. Potential molecular mechanisms were analyzed via western blotting, immunohistochemistry, and flow cytometric analysis. RESULTS: The findings revealed that sRAGE overexpression significantly increased the numbers of Tregs. Depletion of Tregs abrogated the protective effects of sRAGE against I/R-induced cardiac dysfunction, myocardial fibrosis, and inflammatory response in cardiac-specific sRAGE transgenic mice. Mechanistically, sRAGE was found to enhance the expression of programmed cell death ligand 1 (PD-L1) and its upstream JAK2/STAT3 signaling axis, thereby facilitating CD4+ T cells differentiation into Tregs within myocardial tissue during I/R. CONCLUSIONS: The study demonstrated that sRAGE protected against myocardial I/R injury by modulating the differentiation of Tregs through upregulation of the JAK2/STAT3-PD-L1 signaling pathway.