MicroRNA-92a-3p regulates the expression of cartilage-specific genes by directly targeting histone deacetylase 2 in chondrogenesis and degradation.

Increased activity of histone deacetylase 2 (HDAC2) has been found in patients with osteoarthritis (OA) and cartilage matrix degradation and has been shown to mediate the repression of cartilage-specific gene expression in human chondrocytes. We aimed to determine whether microRNA-92a-3p (miR-92a-3p) regulates cartilage-specific gene expression via targeted HDAC2 in chondrogenesis and degradation. miR-92a-3p expression was assessed in vitro in a human mesenchymal stem cells (hMSCs) model of chondrogenesis and in normal and OA primary human chondrocytes (PHCs), and in normal and OA human cartilage by in situ hybridization. hMSCs and PHCs were transfected with miR-92a-3p or its antisense inhibitor (anti-miR-92a-3p), respectively. PHCs were transfected with miR-92a-3p or anti-miR-92a-3p for 24 h before chromatin immunoprecipitation (ChIP) assay was performed with anti-ac-H3 antibody. Direct interaction between miR-92a-3p and its putative binding site in the 3'-untranslated region (3'-UTR) of HDAC2 mRNA was confirmed by luciferase reporter assay. miR-92a-3p expression was elevated in chondrogenic and hypertrophic hMSC, while reduced in OA cartilage compared with normal cartilage. The overexpression of miR-92a-3p suppressed the activity of a reporter construct containing the 3'-UTR and inhibited HDAC2 expression in both hMSCs and PHCs, while treatment with anti-miR-92a-3p enhanced HDAC2 expression. ChIP assays showed that miR-92a-3p enhances H3 acetylation on aggrecan (ACAN), cartilage oligomeric protein (COMP) and Col2a1 promoter, and also promotes relative cartilage matrix expression. Our results suggest that miR-92a-3p regulates cartilage development and homeostasis, which directly targets HDAC2, indicating histone hyperacetylation plays an important role in increased expression of cartilage matrix.

Mao G ，Zhang Z ，Huang Z ，Chen W ，Huang G ，Meng F ，Zhang Z ，Kang Y ... -  《-》

MicroRNA-193b-3p regulates chondrogenesis and chondrocyte metabolism by targeting HDAC3.

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 ... -  《Theranostics》

Exosomes derived from miR-92a-3p-overexpressing human mesenchymal stem cells enhance chondrogenesis and suppress cartilage degradation via targeting WNT5A.

Mao G ，Zhang Z ，Hu S ，Zhang Z ，Chang Z ，Huang Z ，Liao W ，Kang Y ... -  《Stem Cell Research & Therapy》

MicroRNA-92a-3p Regulates Aggrecanase-1 and Aggrecanase-2 Expression in Chondrogenesis and IL-1β-Induced Catabolism in Human Articular Chondrocytes.

Aggrecanase-1 (ADAMTS-4) and aggrecanase-2 (ADAMTS-5) are secreted enzymes belonging to the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family that play significant roles in the progression of osteoarthritis (OA). Here, we aimed to determine whether the expression of ADAMTS-4/5 in chondrogenesis and inflammation is regulated by microRNA-92a-3p (miR-92a-3p). MiR-92a-3p and ADAMTS-4/5 expressions were determined by quantitative polymerase chain reaction (qPCR). To investigate the repressive effect of miR-92a-3p on ADAMTS-4/5 expression, chondrogenic human mesenchymal stem cells (hMSCs) and human chondrocytes were transfected with mature miR-92a-3p or an antisense inhibitor (anti-miR-92a-3p), respectively. ADAMTS-4/5 protein production was quantified by enzyme-linked immunosorbent assay (ELISA), and miR-92a-3p involvement in IL-1β-mediated catabolic effects was examined by immunoblotting. The roles of activated MAP kinases (MAPK) and nuclear factor (NF)-κB were evaluated by using specific inhibitors. Interaction between miR-92a-3p and its putative binding site in the 3'-untranslated region (3'-UTR) of ADAMTS-4/5 mRNA was confirmed by luciferase reporter assay. miR-92a-3p expression was elevated in chondrogenic hMSCs, with significantly lower expression in OA cartilage than in normal cartilage. Stimulation with IL-1β significantly reduced miR-92a-3p expression in primary human chondrocytes (PHCs). Transfection of chondrocytes with miR-92a-3p downregulated IL-1β-induced ADAMTS-4/5 expression, and the activity of a reporter construct containing the 3'-UTR of human ADAMTS-4/5 mRNA. MiR-92a-3p expression was suppressed upon IL-1β-induced activation of MAPK and NF-κB in chondrocytes. MiR-92a-3p is an important regulator of ADAMTS-4/5 in human chondrocytes and may contribute to the development of OA.

Mao G ，Wu P ，Zhang Z ，Zhang Z ，Liao W ，Li Y ，Kang Y ... -  《-》

MicroRNA-455-3p modulates cartilage development and degeneration through modification of histone H3 acetylation.

Histone acetylation regulated by class I histone deacetylases (HDACs) plays a pivotal role in matrix-specific gene transcription and cartilage development. While we previously demonstrated that microRNA (miR)-455-3p is upregulated during chondrogenesis and can enhance early chondrogenesis, the mechanism underlying this process remains largely unclear. In this study, we characterized the effect of miR-455-3p on histone H3 acetylation and its role during cartilage development and degeneration. We observed that miR-455-3p was highly expressed in proliferating and pre-hypertrophic chondrocytes, while HDAC2 and HDAC8 were primarily expressed in hypertrophic chondrocytes. Meanwhile, miR-455-3p suppressed the activity of reporter constructs containing the 3'-untranslated regions of HDAC2/8, inhibited HDAC2/8 expression and promoted histone H3 acetylation at the collagen 2 (COL2A1) promoter in human SW1353 chondrocyte-like cells. Treatment with the HDAC inhibitor trichostatin A (TSA) resulted in increased expression of cartilage-specific genes and promoted glycosaminoglycan deposition. Moreover, TSA inhibited matrix metalloproteinase 13 (Mmp13) expression and promoted nuclear translocation of SOX9 in interleukin-1-treated primary mouse chondrocytes. Lastly, knockdown of HDAC2/3/8 increased SRY (sex-determining region Y)-box 9 (SOX9) and decreased Runt-related transcription factor 2 (RUNX2) expression. Taken together, these findings suggest that miR-455-3p plays a critical role during chondrogenesis by directly targeting HDAC2/8 and promoting histone H3 acetylation, which raises possibilities of using miR-455-3p to influence chondrogenesis and cartilage degeneration.

Chen W ，Chen L ，Zhang Z ，Meng F ，Huang G ，Sheng P ，Zhang Z ，Liao W ... -  《-》