LncRNA CTBP1-AS2 is upregulated in osteoarthritis and increases the methylation of miR-130a gene to inhibit chondrocyte proliferation.

LncRNA CTBP1-AS2 has been reported to be involved in type 2 diabetes and cardiomyocyte hypertrophy, while its roles in other human diseases are unknown. Our preliminary deep sequencing analysis showed altered expression of CTBP1-AS2 in osteoarthritis (OA). In addition, CTBP1-AS2 was inversely correlated with miR-130a. This study was therefore carried out to investigate the interactions between CTBP1-AS2 and miR-130a in OA. Synovial fluid was collected from 62 OA patients and 62 healthy controls. RT-qPCR was performed to determine the expression levels of CTBP1-AS2 and miR-130a in synovial fluid. Cell transfections were performed to investigate the interactions between CTBP1-AS2 and miR-130a. Methylation-specific PCR (MSP) was performed to assess the effects of CTBP1-AS2 on the methylation of miR-130a. Cell counting Kit-8 (CCK-8) assay was performed to evaluate the roles of CTBP1-AS2 and miR-130a in regulating proliferation of chondrocytes. The results showed that CTBP1-AS2 was upregulated in OA and inversely correlated with miR-130a. In chondrocytes of OA patients, overexpression of CTBP1-AS2 led to increased methylation of miR-130a gene and downregulated expression of miR-130a, while overexpression of miR-130a did not affect the expression of CTBP1-AS2. In contrast, no interaction between CTBP1-AS2 and miR-130a was observed in chondrocytes from healthy adults. Analysis of chondrocyte proliferation showed that overexpression of miR-130a led to increased proliferation rate of chondrocytes extracted from OA patients. Overexpression of CTBP1-AS2 led to decreased proliferation rate of chondrocytes and reversed the effects of overexpressing miR-130a. Therefore, CTBP1-AS2 is upregulated in OA and may increase the methylation of miR-130a gene to inhibit chondrocyte proliferation. Key Points • CTBP1-AS2 is overexpressed in OA and may downregulate miR-130a through methylation to suppress the proliferation of chondrocytes. • The interaction between CTBP1-AS2 and miR-130a is indirect and mediated by certain pathological mediators.