The Regulatory Role of microRNA-21 in Coronary Microcirculation in Metabolic Syndrome

Coronary vasculature is essential to supply oxygen and nutrients to the heart and maintain normal cardiac function. Obstruction of large vessels of coronaries (atherosclerosis) is well studied, but coronary microvascular dysfunction (CMD), which is associated with diabetic cardiomyopathy, Takotsubo cardiomyopathy, Ischemia with the non-obstructive coronary artery (INOCA), and HFpEF, is understudied. CMD is characterized by impaired endothelial-dependent vasodilation, but detailed mechanisms have yet to be elucidated. The anti-fibrotic role of microRNA-21 (miR-21) is reported in the HFrEF induced by ischemia/reperfusion or pressure overload, but how miR-21 regulates CMD is not entirely understood. Our recent study shows miR-21 ablation ameliorated impaired vasodilation in isolated coronaries of mice fed on high fat and high sugar (HFHS) diet. In this study, we examined the coronary flow reserve (CFR), the relationship between myocardial blood flow (MBF) and cardiac work (doppler) under hyperemia, cardiac function (echocardiography and exercise exertion test), fibrosis and gene expression of miR-21 knockout and wild-type (WT) mice fed on chow or HFHS diet. Our preliminary data show that MBF and CFR were decreased, cardiac index, stroke volume, and running distance were reduced, and the E/E’ ratio was increased in WT mice fed on the HFHS diet compared to the WT mice fed on the chow diet. The perivascular fibrosis was increased in the WT mice fed on the HFHS diet compared to WT mice on the chow diet. The ablation of miR-21 reversed all these changes in the mice treated with HFHS, suggesting miR-21 deficiency ameliorated CMD in metabolic syndrome. Moreover, we used endothelial-specific miR-21 knockout to study the endothelial miR-21 function. Interestingly, the endothelial mi-R21 KO phenocopied the global knockouts, suggesting the benefit of miR-21 deficiency to coronary microvascular function in metabolic syndrome is from endothelial cells. The study provides the potential therapeutic strategy to target vascular endothelial cells with miR-21 antagomir for CMD in metabolic syndromes. AHA 970663,1R56HL165207,1 R01 HL165207-01A1 to LY and 1 F31 HL156726-01A1 to CJ. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.