question: Does MicroRNA-21 (miR-21) contribute to cardiovascular disease?
answer: MicroRNA-21 (miR-21) is a highly expressed microRNA (miRNA) in cardiovascular system. Recent studies have revealed that its expression is deregulated in heart and vasculature under cardiovascular disease conditions such as proliferative vascular disease, cardiac hypertrophy and heart failure, and ischemic heart disease. miR-21 is found to play important roles in vascular smooth muscle cell proliferation and apoptosis, cardiac cell growth and death, and cardiac fibroblast functions. Accordingly, miR-21 is proven to be involved in the pathogenesis of the above-mentioned cardiovascular diseases as demonstrated by both loss-of-function and gain-of-function approaches