MicroRNAs in chondrogenesis, articular cartilage, and osteoarthritis: implications for tissue engineering.

Coordinated actions of various regulators, including morphogens are required for chondrogenesis and maintenance of articular cartilage function. Bone morphogenetic proteins, and related signaling molecules and transcription factors form a complex regulatory network. MicroRNAs (miRNAs) are noncoding small RNAs that negatively regulate the expression of downstream targets by repressing the translation or inducing the cleavage of messenger RNAs (mRNAs). Increasing evidence indicates that miRNAs are an integral part of the regulatory network in chondrocyte differentiation and cartilage function. The aim of this article is to review the progress in miRNA expression and target genes in cartilage differentiation, homeostasis, and in the pathobiology of osteoarthritis. The recent progress in miRNAs in cartilage has implications for tissue engineering.