Current Status and Strategy of microRNA Research for Cartilage Development and Osteoarthritis Pathogenesis.

MicroRNAs (miRNAs), which are small (~21 nucleotides) non-coding RNAs, are important players in endochondral ossification, articular cartilage homeostasis, and arthritis pathogenesis. Comprehensive and genetic analyses of cartilage-specific or cartilage-related miRNAs have provided new information on cartilage development, homeostasis, and related diseases. State-of-the-art combinatorial approaches, including transcription-activator like effector nuclease (TALEN)/clustered regularly interspaced short palindromic repeats (CRISPR) technique for targeting miRNAs and high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation for identifying target messenger RNAs, should be used to determine complex miRNA networks and miRNA-dependent cartilage regulation. Use of advanced drug delivery systems involving cartilage-specific miRNAs will accelerate the application of these new findings in arthritis therapy.