MECHANISM OF THE ACTIVATION OF LATENT TGF-beta IN THE VASCULAR WALL

血管壁中潜在 TGF-β 的激活机制

基本信息

批准号：
06836015
负责人：
SATO Yasufumi
金额：
$ 1.28万
依托单位：
TOHOKU UNIVERSITY (1995)大分医科大学 (1994)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06836015/
关键词：
latent TGF-beta binding activation LAP smooth muscle cell u-PA u-PA receptor 合成ペプチド内皮細胞モノクローナル抗体 uPA uPA受容体

项目摘要

TGF-beta is one of the most important cytokines affecting the course of vascular diseases including atherosclerosis. Since TGF-beta is always secreted in a latent from, the activation of latent TGF-beta after secretion is the crucial step expressing its activity. The present investigator has previously found that latent TGF-beta is activated when endothelial cells (ECs) and smooth muscle cells (SMCs) are in contact. This activation requires u-PA-plasmin activities expressed on ECs and latent TGF-beta bound to SMCs. Since SMCs are not always in contact with ECs in the vascular wall, a mechanism for the activation of latent TGF-beta in homotypic SMCs needs to be elucidated.The present study revealed that SMCs expressed urokinase-type PA (u-PA) receptor on the cell surface. When exogenous u-PA was added to SMC cultures, u-PA bound to the receptor and expressed its activity on the cell surface. Under this condition, latent TGF-beta was efficiently activated. This effect of u-PA on the activatipn of latent TGF-beta was abrogated by the monoclonal antibody against latency-assosiated peptide (LAP) ; KM-704, which inhibits the binding of latent TGF-beta to SMCs. These results indicate that the simultaneous bindings of u-PA and latent TGF-beta generates active TGF-beta in homotypic SMCs. The binding property of lanent TGF-beta to SMCs was further characterized. The epitope of KM-704 was found to be located on the N-terminal region of LAP consisted with about 80 amino acids. There is not any known sequences for protein-protein interaction in this region. Thus, latent TGF-beta binds to SMC via a novel binding site to LAP.

TGF-β是影响包括动脉粥样硬化在内的血管疾病进程的最重要的细胞因子之一。由于TGF-beta总是从潜在分泌的，因此分泌后潜伏的TGF-beta的激活是表达其活性的关键步骤。本研究人员先前已经发现，当内皮细胞（ECS）和平滑肌细胞（SMC）接触时，潜在的TGF-β被激活。这种激活需要在ECS和与SMC结合的潜在TGF-beta上表达的U-PA-质蛋白活性。由于SMC并不总是与血管壁中的EC接触，因此需要阐明同型SMC中潜在TGF-β的机制。目前的研究表明，SMCS表达的尿激酶型PA（U-PA（U-PA）受体在细胞表面上。当将外源性U-PA添加到SMC培养物中时，U-PA与受体结合并表达其在细胞表面的活性。在这种情况下，潜在的TGF-β有效地激活了。 U-PA对潜在TGF-β活化症的这种影响被单克隆抗体对潜伏期相关的肽（LAP）废除。 KM-704，它抑制潜在TGF-β与SMC的结合。这些结果表明，U-PA和潜在TGF-BETA的同时结合在同型SMC中产生活性TGF-β。 LANENT TGF-BETA与SMC的结合特性得到了进一步的特征。发现KM-704的表位位于LAP的N末端区域，由约80个氨基酸组成。该区域中没有任何已知蛋白质蛋白相互作用的序列。因此，潜在的TGF-β通过新型结合位点与膝盖结合了SMC。