Control systems for the formation and deletion of desmosomal cell-cell contacts in response to extracellular stimuli in keratinocytes

本研究的目的是阐明控制细胞-细胞接触(桥粒)形成和缺失的机制，以及细胞-细胞接触的结构和功能异常引起的大疱性疾病和异常角化的细胞发病机制。自Henning(1982)报道以来，人们已经知道，在低钙(0.1 mm)培养的表皮角质形成细胞不形成桥粒，也不分化，但当钙水平提高到正常水平(1-2 mm)时，桥粒的形成和分化就开始了。然而，人们对这种现象的生化机制知之甚少。此外，已知12-0-二十四碳醇基佛波醇-13-乙酸酯(Tpa)是一种与蛋白激酶C(C…)特异结合并激活的蛋白激酶C，是一种强有力的表皮角质形成细胞分化调节剂。在这方面，我们研究了肌醇磷脂(Ipl)转化和C激酶是否参与了钙诱导的cell-c Kiratincell的形成在低钙生长的细胞中接触更多的细胞。因此，在加钙30秒后，二酰甘油(DG)、磷脂酸和三磷酸肌醇的含量增加，而在加钙15分钟后，已知的由DG引起的C激酶的激活也被显示出来。这些结果提示，细胞内钙离子浓度的增加可能是通过激活IPL-周转和C-激酶来实现的。这项研究在第12届日本皮肤病研究学会年会上发表，并提交给J.Invest。另一方面，在低钙培养液中加入TPA(10 ng/ml)，15分钟后，膜组分中的C-激酶活性降低(C-kenase的转位)，形成桥粒，膜组分中的C-激酶被激活。然而，在加入TPA后24小时，发现总C激酶活性降低(下调)，桥粒减少。此外，添加C激酶抑制剂H7导致正常钙生长细胞中桥粒的数量减少。这些结果可能表明C激酶与角质形成细胞中细胞-细胞接触的控制系统有关。天疱疮抗体在钙诱导的角质形成细胞中细胞-细胞接触形成的影响已在《皮肤病学调查》89；169,1987中报道。研究了单纯性大疱性表皮松解症患者角蛋白中间丝(KIF)的异常组织，并将结果提交给J.调查皮肤科。这些结果促使我们开始对KIF和细胞-细胞接触控制系统进行分子研究。较少

The purpose of the present study is to clarify the mechanism for controlling the formation and deletion of cell-cell contacts (desmosomes), and cellular pathogenesis of bullous diseases and sbnormal keratinization caused by structural and functional abnormality of cell-cell contacts.It has been known since Henning's report (1982) that epidermal keratinocytes cultured in low calcium(0.1mM) do not form desmosome and do not differentiate, but upon raising calcium to the normal level (1 to 2 mM) desmosome formation and differentiation are initiated. However, little is known about the biochemical mechanism for this phenomenon. Besides this, it has been known that 12-0-tetra decanolylphorobol-13-acetate (TPA), which specifically binds to and activates protein kinase C (C kinase), acts as a potent modulator of differentiation in epidermal kiratinocytes.In this respect, we studied whether inositol phospholipids (IPL) turnover and C kinase are involved in the calcium-induced formation of cell-c … More ell contacts in low-calcium grown cells. Consequently, an increase in diacylglcerol(DG), phosphatidic acid and inositol-trisphosphate were shown 30 seconds after calcium addition, and an activation of C kinase which was known to be coused by DG, was also revealed 15 min after calcium addition. These results suggest that an increase in eztracellular calcium concentration may be mediated by an activation of IPL-turnover and C kinase. This was reported at 12th Annual Meeting of Japanese Society for Investigative Dermatology and submitted to J. Invest. Dermato.On the other hand, when TPA (10 ng/ml) was added to the low-calcium medium, the formation of desmosomal contacts and activation of C kinase in membrane fractions with a reduction of its activity in cytosol (trsnslocation of C kenase)were induced at 15 min after TPA addition. However, 24h after TPA addition, the reduction of total C kinase activity (down regulation) and a decrease in desmosomes were found. Furthermore, the addition of a C kinase inhibitor, H7, caused the reduction of the number of desmosomes in normal-calcium grown cells. These results may suggest that C kinase has some important relevance to the control systems of cell-cell contacts in keratinocytes.Effects of pemphigus antibody on the calcium-induced formation of cell-cell contacts in keratinocytes were reported in J. Investigative Dermatology, 89; 169, 1987. Abnormal organization of keratin intermediate filaments (KIF) in epidermolysis bullosa simplex was studied and the results were submitted to J. Investigative Dermatology. These resluts prompt us to start the mollecular studies on KIF and cell-cell contacts controlling systems. Less