培养的牛视网膜毛细血管周细胞中的肌动蛋白：形态与功能的相关性

Actin in cultured bovine retinal capillary pericytes: morphological and functional correlation.

作者信息

Chan L S, Li W Y, Khatami M, Rockey J H

出版信息

Exp Eye Res. 1986 Jul;43(1):41-54. doi: 10.1016/s0014-4835(86)80044-6.

Abstract

Actin in cultured bovine retinal capillary pericytes was identified and partially characterized biochemically. The filamentous actin was localized in bovine retinal capillary pericytes using a fluorescent mushroom toxin (nitrobenzoxadiazole-phallacidin) specific for actin. One-dimensional SDS-polyacrylamide-gel electrophoresis of urea-extracted proteins from bovine retinal capillary pericytes revealed a 46,000 MW protein band corresponding to an actin standard, which comprised 7.3% of the total urea-soluble proteins. Actin-activated skeletal muscle myosin Mg2+-ATPase assay, using [gamma-32P]-ATP as substrate, demonstrated functional actin in bovine retinal capillary pericyte extracts after DEAE-cellulose anion-exchange chromatography. The actin-containing protein fractions were eluted at ionic strengths between 0.25 and 0.35 M KCl. The presence of functional actin in pericytes indicated the ability to generate contractile force. This contraction-generating ability may allow pericytes to regulate microvessel caliber and to maintain the integrity of the capillary wall. A lack of this function when pericytes are preferentially lost in diabetic retinal microangiopathy could destabilize the microvessel wall and predispose the capillary to further pathologic changes.

摘要

对培养的牛视网膜毛细血管周细胞中的肌动蛋白进行了鉴定，并对其进行了部分生化特性分析。使用对肌动蛋白具有特异性的荧光蘑菇毒素（硝基苯并恶二唑 - 鬼笔环肽）将丝状肌动蛋白定位在牛视网膜毛细血管周细胞中。对牛视网膜毛细血管周细胞经尿素提取的蛋白质进行一维SDS - 聚丙烯酰胺凝胶电泳，显示出一条与肌动蛋白标准品相对应的46,000 MW蛋白带，其占总尿素可溶性蛋白的7.3%。以[γ-32P] - ATP为底物进行肌动蛋白激活的骨骼肌肌球蛋白Mg2 + - ATP酶测定，结果表明，经DEAE - 纤维素阴离子交换色谱分离后，牛视网膜毛细血管周细胞提取物中存在功能性肌动蛋白。含肌动蛋白的蛋白组分在0.25至0.35 M KCl的离子强度下被洗脱。周细胞中存在功能性肌动蛋白表明其具有产生收缩力的能力。这种产生收缩的能力可能使周细胞能够调节微血管口径并维持毛细血管壁的完整性。当周细胞在糖尿病视网膜微血管病变中优先丢失时，这种功能的缺失可能会使微血管壁不稳定，并使毛细血管易于发生进一步的病理变化。