Theranostics 2018; 8(10):2862-2883. doi:10.7150/thno.23547
MicroRNA-193b-3p regulates chondrogenesis and chondrocyte metabolism by targeting HDAC3
Department of Joint Surgery, First Affiliated Hospital of SunYat-sen University, Guangzhou, Guangdong 510080, China
#Co-first authors: These authors contributed equally to this work.
Histone deacetylase 3 (HDAC3) plays a pivotal role in the repression of cartilage-specific gene expression in human chondrocytes. The aim of this study was to determine whether microRNA-193b-3p (miR-193b-3p) regulates the expression of HDAC3 during chondrogenesis and chondrocyte metabolism.
Methods: miR-193b-3p expression was assessed in a human mesenchymal stem cell (hMSC) model of chondrogenesis, in interleukin-1β (IL-1β)-treated primary human chondrocytes (PHCs), and in non-degraded and degraded cartilage. hMSCs and PHCs were transfected with miR-193b-3p or its antisense inhibitor. A direct interaction between miR-193b-3p and its putative binding site in the 3′-untranslated region (3′-UTR) of HDAC3 mRNA was confirmed by performing luciferase reporter assays. Chondrocytes were transfected with miR-193b-3p before performing a chromatin immunoprecipitation assay with an anti-acetylated histone H3 antibody. To investigate miR-193b-3p-transfected PHCs in vivo, they were seeded in tricalcium phosphate-collagen-hyaluronate (TCP-COL-HA) scaffolds, which were then implanted in nude mice. In addition, plasma exosomal miR-193b-3p in samples from normal controls and patients with osteoarthritis (OA) were measured.
Results: miR-193b-3p expression was elevated in chondrogenic and hypertrophic hMSCs, while expression was significantly reduced in degraded cartilage compared to non-degraded cartilage. In addition, miR-193b-3p suppressed the activity of reporter constructs containing the 3′-UTR of HDAC3, inhibited HDAC3 expression, and promoted histone H3 acetylation in the COL2A1, AGGRECAN, COMP, and SOX9 promoters. Treatment with the HDAC inhibitor trichostatin A (TSA) increased cartilage-specific gene expression and enhanced hMSCs chondrogenesis. TSA also increased AGGRECAN expression and decreased MMP13 expression in IL-1β-treated PHCs. Further, 8 weeks after implanting PHC-seeded TCP-COL-HA scaffolds subcutaneously in nude mice, we found that miR-193b overexpression strongly enhanced in vivo cartilage formation compared to that found under control conditions. We also found that patients with OA had lower plasma exosomal miR-193b levels than control subjects.
Conclusions: These findings indicate that miR-193b-3p directly targets HDAC3, promotes H3 acetylation, and regulates hMSC chondrogenesis and metabolism in PHCs.
Keywords: microRNA-193b-3p, HDAC3, histone acetylation, chondrogenesis, cartilage
Meng F, Li Z, Zhang Z, Yang Z, Kang Y, Zhao X, Long D, Hu S, Gu M, He S, Wu P, Chang Z, He A, Liao W. MicroRNA-193b-3p regulates chondrogenesis and chondrocyte metabolism by targeting HDAC3. Theranostics 2018; 8(10):2862-2883. doi:10.7150/thno.23547. Available from http://www.thno.org/v08p2862.htm