The control mechanism of cell-cell junctions in normal and diseased Keratinocytes

本研究的目的是阐明细胞-细胞连接的形成和解体的控制机制，以及在病变细胞中。作为一个实验系统。我们使用Ca^<2+>诱导正常角质形成细胞和癌细胞系（djm - 1）形成细胞-细胞连接。在低Ca^<2+>培养基中生长的DJM-L细胞未形成细胞间连接；desmosomeKIF。当它们转移到正常（高）Ca^<2+>介质时。凋亡蛋白从细胞质溶胶到质膜的快速易位，形成桥粒，并几乎同时诱导180个kd-hesidesmosome蛋白重组。与这些形态反应相关的是，Ca^<2+>的移位导致了肌醇磷脂的分解，二酰基甘油和IP_3的形成。蛋白激酶C （PKC）激活。Ca^<2+>内流。tpa处理低Ca^<2+>生长的DJM-L细胞也引起与PKC激活相关的桥粒形成。其他pkc激活剂PDBU和DOG也能诱导桥粒形成。正常Ca^<2+>生长的细胞的治疗破坏了180kd -半粒酶蛋白的有组织分布，并似乎使该蛋白从细胞- ecm粘附位点分离。从这个结果可以推测，细胞对ECM的附着力可能会降低。这些结果表明，PKC激活在与角质形成细胞分化相关的细胞-细胞连接上调和细胞- ecm连接下调中起重要作用。单纯大疱性表皮溶解作为病变细胞进行了研究。在培养的角质细胞中。角蛋白辐射间丝聚集形成球状结构。这是国际上首次报道（1989年），表明该疾病具有角蛋白丝的内在异常。研究了pesphigus抗体对口腔粘膜角质形成细胞的影响，发现其对表皮角质形成细胞的影响不同。

The purpose of this study is to elucidate the control mechanisms of lthe formation and disintegration of cell-cell junctions and that in diseased cells. As an experimental system. we empployed Ca^<2+>-induced cell-cell junction formation using normal keratinocytes and a cancer cell line (DJM-l). DJM-L cells grown in low Ca^<2+> medium did not form cell-cell junctions ; desmosomeKIF. When they were shifted to normal (high) Ca^<2+> medium. a rapid translocation of desnoplakins from the cytosol to the plasma membrane to fors desmosomes and reorganization of 180 kd-hesidesmosome proteins were induced almost simultaneously. In correlation with these morphological responses, the Ca^<2+> shift caused a breakdown of inositol phospholipids, a formation of diacylglycerol and IP_3. protein kinase C (PKC) activation. and Ca^<2+> influx. TPA-treatment of low Ca^<2+>-grown DJM-L cells also caused desmosome formation in association with PKC activation. Treatment with other PKC-activating a gents PDBU and DOG also induced desmosome formation. TPAtreatment of normal Ca^<2+>-grown cells collapsed the organized distribution of the 180 kd-hemidesmosome protein and appeared to detach this protein from the cell-ECM adhering sites. From this result, it may be speculated, -that the attachment force of the cells to ECM may be reduced. These results suggest that PKC activation plays important roles in upregulation of cell-cell junctions and downregulation of cell-ECM junctions in association with differentiation of keratinocytes. As diseased cells, epidersolysis bullosa simplex was studied. In cultured keranocytes. keratin interradiate filaments were found io be aggregated ant to form a ball-like structure. This was the first report (1989) in the world, suggesting that this disease has an intrinsic abnoramlity in keratin filaments. The effects of pesphigus antibody on oral mucasal keratinocytes were studied and different effects from on epidernal keratinocytes were found.