title: Cyclical compressive stress induces differentiation of rat primary mandibular condylar chondrocytes through phosphorylated myosin light chain II.
abstract: The role of myosin light chain II (MLC‑II) in cellular differentiation of rat mandibular condylar chondrocytes (MCCs) induced by cyclical uniaxial compressive stress (CUCS) remains unclear. In the current study, a four‑point bending system was used to apply CUCS to primary cultured MCCs from rats. It was identified that CUCS stimulated features of cellular differentiation including morphological alterations, cytoskeleton rearrangement and overproduction of proteoglycans. Furthermore, CUCS promoted runt‑related transcription factor‑2 (RUNX2) expression at mRNA (P<0.01) and protein levels (P<0.05) and elevated alkaline phosphatase (ALP) activity (P<0.01), which are both markers of osteogenic differentiation. Under conditions of stress, western blotting indicated that the ratio of phosphorylated MLC‑II to total MLC‑II was increased significantly (P<0.05). Silencing MLC‑II by RNA interference reduced ALP activity (P<0.01), and eliminated RUNX2 mRNA expression (P<0.01). Addition of the MLC kinase inhibitor, ML‑7, reduced the CUCS‑associated upregulation of RUNX2 expression (P<0.01) and ALP activity (P<0.01). The data indicated that CUCS promoted cellular differentiation of rat primary MCCs, and this was suggested to be via the phosphorylation of MLC‑II.
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Limin
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Mai
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Zhuli
authors.initials: Z
authors.lastname: Peng
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Kafung
authors.initials: K
authors.lastname: Yu
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Guanqi
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Stomatology, The Third Affiliated Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510630, P.R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Ai
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000235:genetics; D000818:Animals; D001381:Azepines / Q000008:administration & dosage; D024722:Cardiac Myosins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000096:biosynthesis* / Q000235:genetics; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008335:Mandibular Condyle / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D018994:Myosin Light Chains / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D009281:Naphthalenes / Q000008:administration & dosage; D010012:Osteogenesis / Q000235:genetics*; D010766:Phosphorylation; D011312:Pressure; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats
chemical_list: D001381:Azepines; D050659:Core Binding Factor Alpha 1 Subunit; D018994:Myosin Light Chains; D009281:Naphthalenes; D012333:RNA, Messenger; C493717:Runx2 protein, rat; C107184:myosin light chain 2; C070571:ML 7; D000469:Alkaline Phosphatase; D024722:Cardiac Myosins