The Emerging Role of miR-200 Family in Cardiovascular Diseases.

Abstract

Recent studies have shown that reactive oxygen species increase the expression of miR-200 family (miR-200); however, little is known about this micro-RNA family in the cardiovascular system. In this Viewpoint, we provide evidence suggesting that miR-200 may be important in conditions that affect the heart and blood vessels. Oxidative stress plays a major role in cardiovascular physiopathology and some common conditions including aging, diabetes mellitus, atherosclerosis, and reperfusion injury induce reactive oxygen species (ROS). In 2011, it was first published that endothelial and skeletal muscle cells exposed to oxidative stress, in vitro and in vivo, exhibit a marked increase in miR-2001. Subsequently, ROS ability to induce miR-200 has been confirmed in many cell types. Furthermore, hypoxia enhances miR-429, an miR-200 member, and miR-429 targets HIF-1α (hypoxia-inducible factor-1α) and decreases its expression. Most miR-200 studies have been in the cancer field: miR-200 modulates epithelial–mesenchymal transition by targeting the transcription factors ZEB1 and ZEB2 (Zinc-finger E-box binding homeobox 1 and 2) and circulating miR-200 may represent clinically useful cancer biomarkers. In contrast, the role of miR-200 in CV diseases is still poorly investigated. MiRNAs are short (21–22 nucleotides) noncoding RNAs: their seed sequence (nucleotides 2–8 from the 5′ end) targets specific mRNAs and via this mechanism they inhibit translation and also may modulate mRNA stability. The miR-200 family is composed of 5 members clustered and expressed as 2 separate polycistronic pri-miRNA transcripts: in humans, miR-200c and miR-141 are on chromosome 12; miR-200a, miR-200b, and miR-429 are on chromosome 1. They are also identified by different seed sequences: subgroup I comprises miR-141 and miR-200a; subgroup II includes miR-200b, miR-200c, and miR-429. Because each miRNA can target numerous mRNAs and the 2 miR-200 subgroups have different seed sequences, the functional impact of miR-200 can be profound. The Figure shows the major miR-200c–activated …