The Function and Molecular Mechanism of miR-136 in Osteoarthritis

Abstract：Objective To detect the expression of miR-136 in cartilage of osteoarthritis,and investigate the function and molecular mechanism of miR-136 in chondrocyte. Methods 36 paired cartilage tissues and matched normal cartilage tissues from traumatic amputees were obtained from knee osteoarthritic of patients. Quantitative RT-PCR was applied to detect the ex-pression level of miR-136 in cartilage tissues. miR-136 mimics was transient transfected in order to explore proliferation and apoptosis of chondrocyte. Bioinformatic analysis and dual luciferase reporter assay were used to predict and verify the target gene of miR-136 in chondrocyte.Results The expression level of miR-136 was significantly lower expressed in cartilage of os-teoarthritis compared with normal cartilage tissues(P = 0. 02). Exogenous over-expression of miR-136 could significantly inhib-it chondrocyte proliferation and increased CASP3 and BAX expression,but decreased BCL-2 expression. BCL-2 was the target gene of miR-136 in chondrocyte. miR-136 could repress BCL-2 expression via binding to complimentary sequences in its mR-NA 3'-untranslated regions(UTRs). Conclusion miR-136 is significantly down-regulated in cartilage of osteoarthritis,over-expression of miR-136 can significantly inhibit chondrocyte proliferation and induced apoptosis. BCL-2 is a directly target gene of miR-136 in chondrocyte,miR-136 might involve in the occurrence of osteoarthritis by suppressing BCL-2.