Emerging evidence indicates that long non-coding RNAs (lncRNAs) play a vital role in cardiovascular physiology and pathology. Although the lncRNA TUG1 is implicated in atherosclerosis, its function in calcific aortic valve disease (CAVD) remains unknown.

In this study, we found that TUG1 was highly expressed in human aortic valves and primary valve interstitial cells (VICs). Moreover, TUG1 knockdown induced inhibition of osteoblast differentiation in CAVD both in vitro and in vivo. Mechanistically, silencing of TUG1 increased the expression of miR-204-5p and subsequently inhibited Runx2 expression at the post-transcriptional level. Importantly, TUG1 directly interacted with miR-204-5p and downregulation of miR-204-5p efficiently reversed the suppression of Runx2 induced by TUG1 short hairpin RNA (shRNA). Thus, TUG1 positively regulated the expression of Runx2, through sponging miR-204-5p, and promoted osteogenic differentiation in CAVD.

All together, the evidence generated by our study elucidates the role of lncRNA TUG1 as a miRNA sponge in CAVD, and sheds new light on lncRNA-directed diagnostics and therapeutics in CAVD.