Abstract

Background and aims Low-grade chronic inflammation was reported to serve as a distinctive pathophysiologic feature of coronary artery disease (CAD), the leading cause of death around the world. Herein, the current study aimed to explore whether and how microRNA-34c-5p (miR-34c-5p), a miRNA enriched in extracellular vesicles (EVs) originated from the activated platelet (PLT-EVs), affects the inflammation of human coronary artery endothelial cells (HCAECs). Methods and results HCAECs were established as an in vitro cell model using oxidized low-density lipoprotein (ox-LDL). miR-34c-5p, an abundant miRNA in PLT-EVs, can be transferred to HCAECs and target PODXL by binding to its 3′UTR. Gain- and loss-of-function experiments of miR-34c-5p and podocalyxin (PODXL) were performed in ox-LDL-induced HCAECs. Subsequently, HCAECs were subjected to co-culture with PLT-EVs, followed by detection of the expression patterns of key pro-inflammatory factors. Either miR-34c-5p mimic or PLT-EVs harboring miR-34c-5p attenuated the ox-LDL-evoked inflammation in HCAECs by suppressing interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α). By blocking the P38 MAPK signaling pathway , miR-34c-5p-mediated depletion of PODXL contributed to protection against ox-LDL-induced inflammation. In vitro findings were further validated by findings observed in ApoE knock-out mice. Additionally, miR-34c-5p in PLT-EVs showed an athero-protective role in the murine model. Conclusion Altogether, our findings highlighted that miR-34c-5p in PLT-EVs could alleviate inflammation response in HCAECs by targeting PODXL and inactivation of the P38 MAPK signaling pathway.