Santulli R J, Derian C K, Darrow A L, Tomko K A, Eckardt A J, Seiberg M, Scarborough R M, Andrade-Gordon P
R. W. Johnson Pharmaceutical Research Institute, Spring House, PA 19477, USA.
Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9151-5. doi: 10.1073/pnas.92.20.9151.
Thrombin receptor activation was explored in human epidermal keratinocytes and human dermal fibroblasts, cells that are actively involved in skin tissue repair. The effects of thrombin, trypsin, and the receptor agonist peptides SFLLRN and TFRIFD were assessed in inositolphospholipid hydrolysis and calcium mobilization studies. Thrombin and SFLLRN stimulated fibroblasts in both assays to a similar extent, whereas TFRIFD was less potent. Trypsin demonstrated weak efficacy in these assays in comparison with thrombin. Results in fibroblasts were consistent with human platelet thrombin receptor activation. Keratinocytes, however, exhibited a distinct profile, with trypsin being a far better activator of inositolphospholipid hydrolysis and calcium mobilization than thrombin. Furthermore, SFLLRN was more efficacious than thrombin, whereas no response was observed with TFRIFD. Since our data indicated that keratinocytes possess a trypsin-sensitive receptor, we addressed the possibility that these cells express the human homologue of the newly described murine protease-activated receptor, PAR-2 [Nystedt, S., Emilsson, K., Wahlestedt, C. & Sundelin, J. (1994) Proc. Natl. Acad. Sci. USA 91, 9208-9212]. PAR-2 is activated by nanomolar concentrations of trypsin and possesses the tethered ligand sequence SLIGRL. SLIGRL was found to be equipotent with SFLLRN in activating keratinocyte inositolphospholipid hydrolysis and calcium mobilization. Desensitization studies indicated that SFLLRN, SLIGRL, and trypsin activate a common receptor, PAR-2. Northern blot analyses detected a transcript of PAR-2 in total RNA from keratinocytes but not fibroblasts. Levels of thrombin receptor message were equivalent in the two cell types. Our results indicate that human keratinocytes possess PAR-2, suggesting a potential role for this receptor in tissue repair and/or skin-related disorders.
在人类表皮角质形成细胞和人类真皮成纤维细胞（这两种细胞都积极参与皮肤组织修复）中研究了凝血酶受体激活情况。在肌醇磷脂水解和钙动员研究中评估了凝血酶、胰蛋白酶以及受体激动剂肽SFLLRN和TFRIFD的作用。在这两种检测中，凝血酶和SFLLRN对成纤维细胞的刺激程度相似，而TFRIFD的效力较弱。与凝血酶相比，胰蛋白酶在这些检测中显示出较弱的效力。成纤维细胞中的结果与人类血小板凝血酶受体激活情况一致。然而，角质形成细胞表现出不同的特征，胰蛋白酶作为肌醇磷脂水解和钙动员的激活剂远比凝血酶有效。此外，SFLLRN比凝血酶更有效，而TFRIFD未观察到反应。由于我们的数据表明角质形成细胞拥有一种对胰蛋白酶敏感的受体，我们探讨了这些细胞表达新描述的小鼠蛋白酶激活受体PAR - 2的人类同源物的可能性[Nystedt, S., Emilsson, K., Wahlestedt, C. & Sundelin, J. (1994) Proc. Natl. Acad. Sci. USA 91, 9208 - 9212]。PAR - 2可被纳摩尔浓度的胰蛋白酶激活，并具有拴系配体序列SLIGRL。发现SLIGRL在激活角质形成细胞肌醇磷脂水解和钙动员方面与SFLLRN等效。脱敏研究表明，SFLLRN、SLIGRL和胰蛋白酶激活一种共同的受体PAR - 2。Northern印迹分析在角质形成细胞而非成纤维细胞的总RNA中检测到PAR - 2的转录本。两种细胞类型中凝血酶受体信息的水平相当。我们的结果表明人类角质形成细胞拥有PAR - 2，提示该受体在组织修复和/或皮肤相关疾病中可能发挥作用。
