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

本研究旨在阐明细胞-细胞接触（桥粒）形成和缺失的调控机制，以及细胞-细胞接触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的报告（1982）以来，人们已经知道，在低钙（0.1mM）条件下培养的表皮角质形成细胞不形成桥粒，也不分化，但当钙升高到正常水平（1 ~ 2mm）时，桥粒形成和分化开始。然而，对这一现象的生化机制知之甚少。此外，已知12-0-四癸醇-13-乙酸酯（TPA）特异性结合并激活蛋白激酶C （C激酶），是表皮角化细胞分化的有效调节剂。在这方面，我们研究了肌醇磷脂（IPL）的转换和C激酶是否参与钙诱导的细胞C - C的形成。因此，在加钙30秒后，二酰基甘油（DG）、磷脂酸和肌醇-三磷酸增加，并且在加钙15分钟后，已知由DG引起的C激酶活化也被发现。这些结果表明，细胞外钙浓度的增加可能是由ipl -营业额和C激酶的激活介导的。该研究结果在第12届日本皮肤病研究学会年会上发表，并提交给J. Invest。Dermato。另一方面，当TPA （10 ng/ml）添加到低钙培养基中时，TPA添加15 min后可诱导桥粒接触的形成和膜组分C激酶的激活，并降低其在细胞质中的活性（C激酶的转运）。然而，添加TPA 24h后，发现总C激酶活性降低（下调），桥粒减少。此外，C激酶抑制剂H7的加入导致正常钙生长细胞中桥粒数量的减少。这些结果可能表明C激酶与角化细胞中细胞间接触的控制系统有一些重要的相关性。天疱疮抗体对钙诱导的角化细胞细胞接触形成的影响[j] .皮肤病学调查，1989；169年,1987年。本文研究了单纯大疱性表皮松解症中角蛋白中间丝（KIF）的异常组织，结果发表在《皮肤病学研究》杂志上。这些结果促使我们开始对KIF和细胞-细胞接触控制系统的分子研究。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