MicroRNA-320 regulates matrix metalloproteinase-13 expression in chondrogenesis and interleukin-1β-induced chondrocyte responses

Background/Aims: Osteoarthritis (OA) is one of the most common chronic degenerative diseases. Many studies have demonstrated the role of microRNAs (miRNAs) in OA; however, the role of miR-302b in OA remains elusive. The aim of this study was to identify the role of miR-302b in LPS-induced injury in chondrocytes. Methods: Human OA chondrocytes (C28/12 cell line) were transfected with miR-302b inhibitor and miR-302b mimic to investigate the effects of miR-302b expression on chondrocyte apoptosis and inflammation, and to identify the miR-302b target proteins. Results: LPS treatment of chondrocytes significantly reduced cell viability and increased apoptotic rate. LPS treatment also increased the expression of inflammatory cytokines compared to control. miR-302b was up-regulated in LPS-induced chondrocytes. miR-302b was either suppressed or overexpressed in LPS-induced chondrocytes by transient transfection. miR-302b mimic transfection accelerated the effects of LPS on cell viability, apoptosis and inflammation. Of contrast, miR-302b inhibition represented a reverse effect. Dual luciferase activity demonstrated that Smad3 is a direct target for miR-302b and its expression was negatively regulated by miR-302b. In addition, miR-302b inhibition suppressed inflammation in LPS treated chondrocytes by up-regulating Smad3 expression. Moreover, LPS induced down-regulation of Notch and mTOR signaling pathway-related protein expressions, and miR-302b inhibition increased the expressions of Notch and mTOR signaling pathway-related proteins. We further found that miR-302b negatively regulated Notch2 levels through direct targeting its 3’UTR. Conclusions: These results suggest that miR-302b suppression may function as a protector in suppressing the inflammation during the development and progression of OA by up-regulating the target Smad3 expression.

Section: Discussionmentioning

confidence: 99%

Knockdown MiR-302b Alleviates LPS-Induced Injury by Targeting Smad3 in C28/I2 Chondrocytic Cells

Wang

Jin

et al. 2018

“…Immunohistochemical analysis was performed as described previously [32]. Formalin-fixed and paraffin-embedded cartilage specimens were sectioned and stained with Safranin O for histological evaluation.…”

Section: Immunohistochemical Analysismentioning

confidence: 99%

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

Mao¹,

Zhang²,

Zhang³

et al. 2017

Background/Aims: 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). Methods: 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 miR92a-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. Results: 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.

“…In recent years, miRNAs have gained increasing importance due to their regulation of the expression of various genes, including cartilage-specific genes [15][16][17]20]. miR-320c specifically has been shown to promote embryonic development in mice [29] and regulate hBMSC adipocytic differentiation by directly targeting RUNX2 [30].…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies have shown that miR-320c is an important regulator of inflammation [17][18][19]. We previously found that miR-320 regulates IL-1β-induced catabolic effects in ATDC5 cells and directly targets and inhibits MMP13 [17].…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

CDK6 and miR-320c Co-Regulate Chondrocyte Catabolism Through NF-κB Signaling Pathways

Sun¹,

Huang²,

Chang³

et al. 2018

Background/Aims: Cyclin-dependent kinase 6 (CDK6) regulates inflammatory response and cell differentiation. This study sought to determine whether CDK6 and miR-320c co-regulate chondrogenesis and inflammation. Methods: Utilizing quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC), CDK6 and miR-320c expression were assessed in a micromass culture of human bone mesenchymal stem cells that underwent chondrogenesis in vitro as well as in chondrocytes from E16.5 mouse forelimbs. Normal chondrocytes were transfected with miR-320c mimic, miR-320c inhibitor, or CDK6-siRNA. Luciferase reporter assay results confirmed that miR-320c directly targets CDK6 by interacting with the 3′-untranslated region (3′-UTR) of its mRNA. qRT-PCR, Western blotting, and Cell Counting Kit-8 were subsequently used to evaluate the effects of miR-320c overexpression and CDK6 inhibition on inflammatory factor expression, as well as to investigate the effects of NF-kB and MAPK signaling pathway activation on IL-1β-induced chondrocyte inflammation. Results: Our results show that miR-320c expression increased during the middle stage and decreased during the late stage of hBMSC chondrogenic differentiation. In contrast, CDK6 expression decreased during the middle stage and increased during the late stage of hBMSC chondrogenic differentiation. Moreover, CDK6 expression increased in severe OA cartilage and in hypertrophic chondrocytes of mouse forelimbs at E16.5. Results of the luciferase reporter assay showed that miR-320c modulated CDK6 expression by binding to the 3′-UTR of its mRNA. miR-320c overexpression and CDK6 inhibition repressed IL-1β-induced expression of inflammatory factors and regulated the NF-kB signaling pathway. Conclusion: CDK6 and miR-320c co-regulate hBMSC chondrogenesis and IL-1β-induced chondrocyte inflammation through the NF-kB signaling pathway, suggesting that miR-320c and CDK6 inhibitors can be used to repress catabolism in human chondrocytes.