miR-17~92 cluster inhibited meniscal calcification by targeting HIF-1α

Abstract Research background: The meniscus functions as a vital component in maintaining the homeostasis of joint biomechanics, and its pathological calcification leads to cartilage destruction. The cluster of miR-17~92 plays an important role in skeletal development. However, the impact of miR-17~92 on meniscal calcification remains unclear. Methods: To determine the function of miR-17~92 in meniscus, the expression of miR-17~92 in meniscus was deleted by crossing miR-17~92fl/fl mice with transgenic mice Col2-CreERT. Safranin-O, hematoxylin and eosin (H&E) and immunohistochemistry were used to determine the effects of miR-17~92 loss on meniscal calcification. In vitro, we explored the mechanism by knockdown or overexpression of miR-17~92 or hypoxia-inducible factor 1α (HIF-1α) in meniscal cells. Results: Our investigation revealed decreased expression of miR-17, miR-19b, and miR-92a in IL-1β-treated meniscal cells, which corresponded to a significant increase in the expression of calcification-related genes such as COL10A1, RUNX2, MMP13, and VEGFA, as well as a reduction in the expression of COL1A1 and COL2A1. Particularly, miR-17 exhibited a more pronounced inhibitory effect on calcification compared to the other two microRNAs. Furthermore, our findings demonstrated that IL-1β stimulation led to heightened expression of HIF-1α in meniscal cells. Subsequent experiments involving the administration of prolyl hydroxylase-2 (PHD2) inhibitor (IOX2) resulted in a significant increase in the expression of calcification genes, whereas the supplementation of miR-17 decreased HIF-1α expression and reversed these changes. Conversely, treatment with a HIF-1α inhibitor (PX-478) effectively suppressed the calcification phenotype and restored collagen expression. Conclusion: Our data suggests that miR-17 plays an essential role in suppressing meniscal calcification and maintaining the anabolic activities of meniscal cells through its targeting of HIF-1α, thereby underscoring miR-17 as a prospective therapeutic target for addressing meniscal calcification.