Nakai K, Ito C, Yumura W, Horita S, Nihei H, Sugino N, Nagai R
Department of Clinical Pathology, Iwate Medical University, Morioka, Japan.
Nihon Jinzo Gakkai Shi. 1995 Aug;37(8):428-35.
Contraction of the pre- and postglomerular arteries play an important role in the regulation of glomerular blood flow. Mesangial cells may also be involved in the mechanism of this regulation, but it has not been clarified yet whether or not mesangial cells and vascular smooth muscles show an identical phenotype, especially in terms of their contractile proteins. In this study, in order to elucidate any difference in the cellular phenotypes between mesangial cells and renal vascular smooth muscles, we investigated the localization of myosin heavy chain isoforms using a monoclonal antibody against SM1 and SM2. Both SM1 and SM2 are specific to smooth muscles. SM1 is specifically expressed in smooth muscles from early development and SM2 appears after birth. In normal renal tissues, SM1 and SM2 were expressed only in the smooth muscle cells of the arterioles and small arteries. However, glomerular cells, including mesangial cells, were not stained with either anti-SM1 antibody or anti-SM2 antibody. Localization of SM1 and SM-2 was similar to that of alpha-smooth muscle actin (SM alpha-actin). Staining for SM-1 was not observed in the mesangial areas of renal tissues with glomerular disease. These results clearly indicate that mesangial cells have a different phenotype from that of vascular smooth muscle cells in terms of their contractile proteins.
肾小球前动脉和后动脉的收缩在肾小球血流调节中起重要作用。系膜细胞可能也参与了这种调节机制，但系膜细胞和血管平滑肌是否表现出相同的表型，尤其是在其收缩蛋白方面，尚未明确。在本研究中，为了阐明系膜细胞和肾血管平滑肌之间细胞表型的差异，我们使用抗SM1和SM2的单克隆抗体研究了肌球蛋白重链同工型的定位。SM1和SM2均为平滑肌特异性。SM1在发育早期即在平滑肌中特异性表达，而SM2在出生后出现。在正常肾组织中，SM1和SM2仅在小动脉和小动脉的平滑肌细胞中表达。然而，包括系膜细胞在内的肾小球细胞均未被抗SM1抗体或抗SM2抗体染色。SM1和SM-2的定位与α-平滑肌肌动蛋白（SMα-肌动蛋白）相似。在患有肾小球疾病的肾组织系膜区未观察到SM-1染色。这些结果清楚地表明，就收缩蛋白而言，系膜细胞具有与血管平滑肌细胞不同的表型。
