Dual functions of microRNA-17 in maintaining cartilage homeostasis and protection against osteoarthritis

Damaged hyaline cartilage has no capacity for self-healing, making osteoarthritis (OA) difficult-to-treat. Cartilage destruction is central to OA patho-etiology and is mediated by matrix degrading enzymes. Here we report decreased expression of miR-17 in osteoarthritic chondrocytes and its deficiency contributes to OA progression. Supplementation of exogenous miR-17 or its endogenous induction by growth differentiation factor 5, effectively prevented OA by simultaneously targeting pathological catabolic factors including matrix metallopeptidase-3/13 (MMP3/13), aggrecanase-2 (ADAMTS5), and nitric oxide synthase-2 (NOS2). Single-cell RNA sequencing of hyaline cartilage revealed two distinct superficial chondrocyte populations (C1/C2). C1 expressed physiological catabolic factors including MMP2, and C2 carries synovial features, together with C3 in the middle zone. MiR-17 is highly expressed in both superficial and middle chondrocytes under physiological conditions, and maintains the physiological catabolic and anabolic balance potentially by restricting HIF-1 alpha signaling. Together, this study identified dual functions of miR-17 in maintaining cartilage homeostasis and prevention of OA. Osteoarthritic (OA) is characterized by progressive destruction of joint cartilage. Here, the authors show that microRNA-17 plays a dual role in maintaining cartilage homeostasis and in the prevention of osteoarthritis, by targeting hypoxia-inducible factor-1 alpha as well as multiple matrix-degrading enzymes.

Automated summary

This study identifies the dual functions of miR-17 in maintaining cartilage homeostasis and preventing osteoarthritis by targeting hypoxia-inducible factor-1 alpha and multiple matrix-degrading enzymes.