| Co-Investigator(Kenkyū-buntansha) |
TOGUCHIDA Junya Kyoto University, Research Center for Biomedical Engineering, Professor, 生体医療工学研究センター, 助教授 (40273502)
NAKAMURA Takashi Kyoto University, Faculty of Medicine, Department of Orthop.Surg., Professor, 医学研究科, 教授 (10201675)
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| Research Abstract |
From a clinical aspect of joint reconstruction, we have investigated how to repair the joint surface. One of the methods to repair the joint is tissue engineering using cultured chondrocytes which has developed markedly.To repair the joint using cultured chondrocytes, important problem is character of chondrocyte, especially their phenotype as articuler chondrocytes. In other words, it is desirable that the used chondrocytes never ossifies. Considering these character of chondrocytes, we investigated signal transmission of TGF-beta superfamily in chondrocytes. In the present study we examined the effect of phorbol, 12-myristate, 13-acetate (PMA), a potent and specific protein kinase C(PKC) activator and Staurosporine, a potent nonselective PKC inhibitor, on the differentiation of sternal chondrocytes from 13-day-old chick embryo, and whether PKC functions as a mediator of their effects. Sulfated proteoglycan (PG) and type I and type II collagen were used as markers of differentiation. PKC expression was assayd by immunoblotting. PMA inhibited chondrogenesis dose-dependently (1-50 ng/ml), and its effects were possibly mediated by the translocation of PKC from the cytozol to the membrane. Staurosporine enhanced chondrogenesis (1-80nM) and caused the depletion of total PKC in a dose-dependent fashion. A synergistic stimulation of PG synthesis by N-monomethyl, L-arginine (NMA), a specific inhibitor of nitric oxide synthase (NOS), in response to Staurosporine (4 and 80 nM), with a corresponding suppression of NO synthesis, has been observed. The effect PMA on PG synthesis was not modulated by NMA.We suggest that NO may no be involved in the inhibition of chick sternal chondrocyte differentiation by PMA,but that Staurosporine may promote chondrogenic differentiation at least in part through a NO-dependent mechanism
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