Single-cell RNA sequencing reveals that dexmedetomidine mediates the regulation of mitochondrial fusion in cardiac fibroblasts through the Serpine1-mediated STAT3/Notch-1 pathway to alleviate doxorubicin- and trastuzumab-induced myocardial fibrosis

Background Myocardial fibrosis is the most direct pathological consequence of cardiotoxicity induced by doxorubicin (Dox) and trastuzumab (Tzb). Therefore, it is crucial to explore strategies for preventing and controlling Dox- and Tzb-induced myocardial fibrosis. This study aimed to examine the role of dexmedetomidine (Dex) in alleviating Dox- and Tzb-induced myocardial fibrosis through single-cell sequencing and to elucidate the underlying regulatory mechanisms of Dex.LE: Title: Please check the edit to the article title.Single-cell RNA sequencing reveals that dexmedetomidine mediates the regulation of mitochondrial fusion in cardiac fibroblasts through the Serpine1-mediated STAT3/Notch-1 pathway to alleviate doxorubicin- and trastuzumab-induced myocardial fibrosis Methods A Dox- and Tzb-induced myocardial fibrosis model was established to explore the therapeutic effects of Dex on myocardial fibrosis. Echocardiography, hemodynamic testing, and histopathological examination were performed to assess cardiac function and myocardial fibrosis. Bioinformatics analyses were conducted on the single-cell sequencing dataset. Hub genes showing differential expression after Dex treatment were primarily identified through differential expression analysis, mouse core gene set scoring, single-cell transcriptome-weighted gene co-expression network analysis (WGCNA), and cell–cell communication analysis. The mechanism underlying Dex’s role in alleviating myocardial fibrosis was investigated in cardiac fibroblasts (CFs) via immunofluorescence staining, quantitative real-time polymerase chain reaction, Western blotting, Cell Counting Kit-8, and wound healing assays. Results Dex effectively alleviated Dox- and Tzb-induced myocardial fibrosis in animal experiments, and 888 differentially expressed genes were identified after single-cell transcriptome sequencing of myocardial tissues. Serpin Family E Member 1 (Serpine1) was ultimately identified though WGCNA as a hub gene. Dex inhibited the differentiation, migration, and mitochondrial fusion of CFs while promoting Serpine1 expression. Inhibition of Serpine1 expression led to enhanced CF differentiation and migration, exacerbated mitochondrial fusion, and regulated the signal transducer and activator of transcription 3 (STAT3)/Notch-1 pathway. Following inhibition of Serpine1 expression, treatment with DAPT, an inhibitor of the Notch pathway, and colivelin, an agonist of STAT3, suppressed CF differentiation and migration and attenuated mitochondrial fusion. Conclusion Dex inhibits mitochondrial fusion by promoting Serpine1 expression, which regulates the STAT3/Notch-1 pathway, thereby inhibiting CF differentiation and ultimately alleviating Dox- and Tzb-induced myocardial fibrosis.