Diabetes Advances Cardiomyocyte Senescence through miR-103a-3p/ Rnd3/STAT3 Signaling

BACKGROUNDRnd3, a small Rho-GTPase, is involved in various cardiovascular diseases, but its role in diabetes-induced cardiomyocyte senescence is unclear. This study aims to investigate the role of Rnd3 in cardiomyocyte senescence in diabetes cardiomyopathy (DCM). METHODSRnd3 expression was assessed in human tissue using qPCR, and its correlation with clinical parameters was analyzed. Rnd3 and Senescence-associated secretory phenotype (SASP)-related marker expression was determined in heart tissue from juvenile/mature mice and streptozotocin-induced diabetic Sprague-Dawley rats. H9C2 and AC16 cardiomyocytes were exposed to high glucose ([HG] =35 mmol/L D-glucose), and Rnd3 and SASP-related marker expression was examined. Rnd3 expression in H9C2 cells was disrupted using CRISPR/Cas9 technology, and cellular senescence of HG-treated H9C2 cells was evaluated. MicroRNA sequencing was conducted on AC16 cells to identify differentially expressed microRNAs regulated by HG. Among these microRNAs, miR-103a-3p was selected for further investigation in a clinical diabetes cohort and to examine its binding to Rnd3 3'UTR and its effect on cell senescence. Finally, the role of interaction of Rnd3 and STAT3 in cardiomyocyte senescence was investigated. RESULTSRnd3 mRNA levels were reduced in peripheral blood mononuclear cells in diabetic patients, which was negatively correlated to patients age but positively correlated to cardiac function. Older mice exhibited compromised cardiac function, increased SA-{beta}-gal-positive cells, and SASP marker levels versus younger mice. HG stimulation inhibited Rnd3 expression but enhanced cellular senescence. Rnd3 knockout resulted in greater cellular senescence on HG-insulted cardiomyocytes. miR-103a-3p was identified as a key HG-regulated microRNA that binds to Rnd3 3'UTR. AAV9 carrying miR-103a-3p sponges and Rnd3-overexpressing plasmids mitigated cellular senescence in diabetic rats. Interestingly, miR-103a-3p levels positively correlated with blood glucose concentrations. HG stimulation amplified phosphorylated STAT3(Tyr705) in H9C2 cells, which was intensified by Rnd3 knockout. Rnd3 binds with STAT3 in cytoplasm and promote proteasome-induced ubiquitination of STAT3. S3I-201 mitigated HG-activated STAT3 and cardiomyocyte senescence. CONCLUSIONDiabetes causes cardiomyocyte senescence through miR-103a-3p/Rnd3/STAT3 signaling, suggesting a potential treatment strategy for DCM.