Long non-coding RNAs in vascular biology and disease.

The advent of deep sequencing technologies recently unraveled the complexity of the human genome: Although almost entirely transcribed, only a very minor part of our genome actually accounts for protein coding exons and most is considered non-coding. Among the non-coding transcripts, long non-coding RNAs (lncRNAs) constitute a rather heterogeneous group of linear as well as circular RNAs (circRNAs). LncRNAs act via multiple mechanisms and several lncRNAs were shown to be involved in vascular development, growth and remodeling. For example, the lncRNAs PUNISHER, MALAT1, MEG3, and GATA6-AS regulate vessel formation in vivo, whereas lincRNA-p21 controls smooth muscle cell function and neointima formation. For several other lncRNAs (e.g. SENCR, SMILR, and HypERlnc) functional roles in smooth muscle cells/pericytes have been described in vitro. Less information is available with respect to the function of circRNAs. Here most studies report on expression profiles but some circRNAs (e.g. cANRIL or cZNF292) may also play critical roles in smooth muscle or endothelial cells in vitro. This review summarizes the current knowledge of lncRNA and circRNA functions in vascular biology and disease and discusses their potential use as biomarkers.