TY - JOUR AB - Malocclusion caused by abnormal jaw development or muscle overuse during mastication results in abnormal mechanical stress to the tissues surrounding the temporomandibular joint (TMJ). Excessive mechanical stress against soft and hard tissues around the TMJ is involved in the pathogenesis of inflammatory diseases, including osteoarthritis (OA). OA-related fibrosis is a possible cause of joint stiffness in OA. However, cellular and molecular mechanisms underlying fibrosis around the TMJ remain to be clarified. Here, we established a cell line of fibroblast‑like synoviocytes (FLSs) derived from the mouse TMJ. Then, we examined whether the Rho‑associated coiled‑coil forming kinase (ROCK)/actin/myocardin-related transcription factor (MRTF) gene regulatory axis positively regulates the myofibroblast (MF) differentiation status of FLSs. We found that i) FLSs extensively expressed the MF markers α‑smooth muscle actin (α‑SMA) and type I collagen; and ii) an inhibitor against the actin‑polymerizing agent ROCK, Y‑27632; iii) an actin-depolymerizing agent cytochalasin B; iv) an inhibitor of the MRTF/serum response factor‑regulated transcription, CCG‑100602, clearly suppressed the mRNA levels of α‑SMA and type I collagen in FLSs; and v) an MF differentiation attenuator fibroblast growth factor‑1 suppressed filamentous actin formation and clearly suppressed the mRNA levels of α-SMA and type I collagen in FLSs. These results strongly suggest that the ROCK/actin/MRTF axis promotes the fibrogenic activity of synoviocytes around the TMJ. Our findings partially clarify the molecular mechanisms underlying the emergence of TMJ‑OA and may aid in identifying drug targets for treating this condition at the molecular level. AD - Division of Cellular Biosignal Sciences, Department of Biochemistry, Iwate Medical University, Iwate 028‑3694, Japan Division of Orthodontics, Department of Developmental Oral Health Science, Iwate Medical University, Iwate 020‑8505, Japan AU - Yokota,Seiji AU - Chosa,Naoyuki AU - Kyakumoto,Seiko AU - Kimura,Hitomichi AU - Ibi,Miho AU - Kamo,Masaharu AU - Satoh,Kazuro AU - Ishisaki,Akira DA - 2017/04/01 DO - 10.3892/ijmm.2017.2896 EP - 808 IS - 4 JO - Int J Mol Med KW - actin myocardin‑related transcription factor fibro-blast‑like synoviocytes temporomandibular joint myofibroblast differentiation PY - 2017 SN - 1107-3756 1791-244X SP - 799 ST - ROCK/actin/MRTF signaling promotes the fibrogenic phenotype of fibroblast-like synoviocytes derived from the temporomandibular joint T2 - International Journal of Molecular Medicine TI - ROCK/actin/MRTF signaling promotes the fibrogenic phenotype of fibroblast-like synoviocytes derived from the temporomandibular joint UR - https://doi.org/10.3892/ijmm.2017.2896 VL - 39 ER -