Long non-coding RNA PVT1, a molecular sponge for miR-149, contributes aberrant metabolic dysfunction and inflammation in IL-1β-simulated osteoarthritic chondrocytes

Osteoarthritis (OA), a common form of degenerative joint disease, is typified by inflammatory response and the loss of cartilage matrix. Long non-coding RNAs (lncRNAs) are emerging as a new player in gene regulation and exert critical roles in diverse physiologic and pathogenic processes including OA. The lncRNA plasmacytoma variant translocation 1 (PVT1) has been implicated in cancer, diabetes and septic acute kidney injury. Recent research confirmed the elevation of PVT1 in patients with OA. However, its role in the development of OA remains poorly elucidated. In the present study, high expression of PVT1 was observed in cartilage of OA patients and IL-1 beta-stimulated chondrocytes. Moreover, cessation of PVT1 expression dramatically reversed the inhibition of IL-1 beta on collagen II and aggrecan expression, but suppressed IL-1 beta-induced elevation of matrix metalloproteinases (MMPs), including MMP-3, MMP-9 and MMP-13. Simultaneously, PVT1 inhibition also antagonized the production of inflammatory cytokines upon IL-1 beta stimulation, including prostaglandin E2 (PGE2), NO, IL-6, IL-8 and TNF-alpha. Further molecular mechanism analysis identified PVT1 as an endogenous sponge RNA that could directly bind to miR-149 and repress its expression and activity. More importantly, miR-149 inhibition reversed the protective roles of PVT1 cessation in attenuating IL-1 beta-evoked matrix aberrant catabolism and inflammation. Together, this research confirms that lowering PVT1 expression may ameliorate the progression of OA by alleviating cartilage imbalance toward catabolism and inflammatory response, thus supporting a promising therapeutic strategy against OA.