The precise patterning of the developing skeletal framework relies on the appropriate control of chondrogenesis, a multistep process during which mesenchymal cells differentiate into chondrocytes. Articular cartilage destruction is a central factor in the pathogenesis of joint diseases, including osteoarthritis (OA) and rheumatoid arthritis (RA). Research on the molecular mechanisms of chondrogenesis is of developmental biological interest and has the potential to lead to novel approaches in tissue engineering and novel arthritis treatments. MicroRNAs (miRNAs) are a family of ~22-nucleotide (nt) noncoding RNAs that regulate gene expression by posttranscriptional mechanisms. To date, chondrocyte specific miRNAs, their upstream molecular signals, and target genes are largely unknown. In our preliminary experiments, we performed microarray profiling of miRNA expression in chondrocytes and miR-140 expression in cartilage development during embryogenesis and adult cartilage chondrocytes. These studies demonstrated that miR-140 has the most cartilage specific expression pattern. Cartilage specific Sox9 null mice did not express miR-140 and the potential Sox9 binding region close to pre-miR-140 was associated with Sox9 by ChIP assay and EMSA, suggesting that Sox9 is a key regulator of miR-140 gene expression. miR-140 expression was down-regulated in osteoarthritic cartilage compared with normal cartilage and by IL-1? stimulation of chondrocytes. miR-140 null mice showed earlier onset of osteoarthritic changes in knee joint at 6 months. Microarray and bioinformatics analysis revealed a set of possible miR-140 target genes in chondrocytes, including ADAMTS-5, which is a key tissue-degrading enzyme in osteoarthritis. These observations support the hypothesis that miR-140 is a novel regulator of cartilage development and homeostasis and those changes in its expression and function play an important role in diseases affecting articular cartilage, such as osteoarthritis. We propose the following specific aims:
Aim 1 : Investigate the transcriptional regulation of miR-140 expression by Sox9 in mesenchymal stem cells and chondrocytes.
Aim 2 : Examine the role of miR-140 in chondrogenesis and cartilage development.
Aim 3 : Determine the expression and function of miR-140 in osteoarthritis.
Aim 4 : Identify novel target genes of miR-140 in chondrocytes and mesenchymal stem cells. The proposed studies have the potential to reveal important new regulatory pathways that control cartilage development and homeostasis and open new insight on disease mechanisms and therapeutic interventions.
Despite substantial recent progress in understanding OA pathogenesis, disease-modifying therapies for the most prevalent joint disease are not available. Examining the role of miR-140 in MSC and chondrocytes may provide new insight into cartilage cell biology as well as a basis for novel approaches in tissue engineering and therapeutic strategies for osteoarthritis.
|Miyata, Kohei; Miyata, Tomoko; Nakabayashi, Kazuhiko et al. (2015) DNA methylation analysis of human myoblasts during in vitro myogenic differentiation: de novo methylation of promoters of muscle-related genes and its involvement in transcriptional down-regulation. Hum Mol Genet 24:410-23|
|Alvarez-Garcia, Oscar; Rogers, Nicole H; Smith, Roy G et al. (2014) Palmitate has proapoptotic and proinflammatory effects on articular cartilage and synergizes with interleukin-1. Arthritis Rheumatol 66:1779-88|
|Onizuka, Naoko; Ito, Yoshiaki; Inagawa, Masayo et al. (2014) The Mohawk homeobox transcription factor regulates the differentiation of tendons and volar plates. J Orthop Sci 19:172-80|
|Akasaki, Y; Hasegawa, A; Saito, M et al. (2014) Dysregulated FOXO transcription factors in articular cartilage in aging and osteoarthritis. Osteoarthritis Cartilage 22:162-70|
|Yoshitaka, Teruhito; Kawai, Akira; Miyaki, Shigeru et al. (2013) Analysis of microRNAs expressions in chondrosarcoma. J Orthop Res 31:1992-8|
|Nakahara, Hiroyuki; Hasegawa, Akihiko; Otabe, Koji et al. (2013) Transcription factor Mohawk and the pathogenesis of human anterior cruciate ligament degradation. Arthritis Rheum 65:2081-9|
|Matsukawa, Tetsuya; Sakai, Tadahiro; Yonezawa, Tomo et al. (2013) MicroRNA-125b regulates the expression of aggrecanase-1 (ADAMTS-4) in human osteoarthritic chondrocytes. Arthritis Res Ther 15:R28|
|Watanabe, Takashi; Oyama, Toshinao; Asada, Maki et al. (2013) MAML1 enhances the transcriptional activity of Runx2 and plays a role in bone development. PLoS Genet 9:e1003132|
|Asada, Maki; Rauch, Alexander; Shimizu, Hirohito et al. (2011) DNA binding-dependent glucocorticoid receptor activity promotes adipogenesis via Kruppel-like factor 15 gene expression. Lab Invest 91:203-15|
|Otsuki, Shuhei; Grogan, Shawn P; Miyaki, Shigeru et al. (2010) Tissue neogenesis and STRO-1 expression in immature and mature articular cartilage. J Orthop Res 28:96-102|
Showing the most recent 10 out of 21 publications