MicroRNAs (miRNAs) play an essential role in articular cartilage development and growth. However, the exact mechanisms involved in this process remain unknown. In the present study, we investigated the biological functions of miR-27b during hypertrophic differentiation of rat articular chondrocytes. Based on in situ hybridization and immunohistochemistry, we report that miR-27b expression is reduced in the hypertrophic zone of articular cartilage, but expression of peroxisome proliferator-activated receptor. (Ppar gamma) is increased. Dual-luciferase reporter gene assay and Western blot analysis demonstrated that Ppar gamma 2 is a target of miR-27b. Overexpression of miR-27b inhibited expression of Ppar gamma 2, as well as type X collagen (Col10a1) and matrix metalloproteinase 13 (Mmp13), while significantly promoting the expression of Sex-determining Region-box 9 (Sox9) and type II collagen (Col2a1) at both the mRNA and protein levels. Rosiglitazone, a Ppar gamma agonist, suppressed Col2a1 expression, while promoting expression of runt-related transcription factor 2 (Runx2) and Col10a1 in a concentration-dependent manner. siRNA-mediated knockdown of Ppar gamma 2 caused an increase in protein levels of Col2a1. The present study demonstrates that miR-27b regulates chondrocyte hypertrophy in part by targetting Ppar gamma 2, and that miR-27b may have important therapeutic implications in cartilage diseases.
[1]Jilin Univ, Coll Basic Med Sci, Minist Educ, Key Lab Pathobiol, Changchun 130000, Jilin, Peoples R China.
[2]Jilin Univ, Sch Pharmaceut Sci, Dept Regenerat Med, Changchun 130000, Jilin, Peoples R China.
[3]Jilin Univ, Hosp 1, Dept Neurosurg, Changchun 130000, Jilin, Peoples R China.
[4]Jilin Univ, Clin Med Coll, Dept Clin Med, Changchun 130000, Jilin, Peoples R China.
[5]Jilin Univ, China Japan Union Hosp, Dept Dermatol, Changchun 130000, Jilin, Peoples R China.
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