Chibber R, Molinatti P A, Rosatto N, Lambourne B, Kohner E M
Department of Endocrinology, Diabetes and Metabolic Medicine, St. Thomas' Hospital, London, UK.
Diabetologia. 1997 Feb;40(2):156-64. doi: 10.1007/s001250050657.
The toxic effects of advanced glycation end products (AGEs) on bovine retinal capillary pericytes (BRP) and endothelial cells (BREC) were studied. AGE-modified bovine serum albumin (AGE-BSA) was toxic to BRP. At a concentration of 500 micrograms/ml it reduced the BRP number to 48 +/- 3% (p < 0.05) of untreated controls, as determined by cell counting with haemocytometer. AGE-BSA was also toxic to bovine aortic endothelial cells (BAEC) reducing cell number to 84 +/- 3.1% of untreated controls. Under similar conditions, low concentrations (62.5 micrograms/ml) of AGE-BSA were mitogenic to BREC increasing the cell proliferation to 156 +/- 11% (p < 0.05) above that of untreated controls. At a higher dose of 500 micrograms/ml AGE-BSA decreased the proliferation of BREC to 85 +/- 6% of untreated controls. Immunoblot analysis demonstrated that BRP and BREC express the p60 AGE-receptor. Retinal capillary bed from the human also stained positively for the p60 AGE-receptor. Addition of 0.25 micrograms/ml of p60 AGE-receptor antibody was able to block the effects of AGE-BSA on BRP and BREC. The level of binding of [125I]-labelled AGE-BSA to the cell surface was small but significant among the three cell types. There was also an increase in the internalized pool of radioligand in BRP and BREC but this was very much lower than in BAEC. In all the cell types the internalized pool of [125I]-labelled AGE-BSA was much larger than the amount associated with the cell surface. Degradation products were not detected in the media over the 24-h incubation of the cells with [125I]AGE-BSA. The binding of [125I]-labelled AGE-BSA to the cell surface was prevented by the addition of p60 AGE-receptor. These results suggest that the interaction of AGE-modified proteins with the membrane-bound AGE-receptor may play an important role in the pathogenesis of diabetic retinopathy.
研究了晚期糖基化终产物（AGEs）对牛视网膜毛细血管周细胞（BRP）和内皮细胞（BREC）的毒性作用。AGE修饰的牛血清白蛋白（AGE-BSA）对BRP具有毒性。通过血细胞计数器进行细胞计数测定，在浓度为500微克/毫升时，它将BRP数量减少至未处理对照的48±3%（p<0.05）。AGE-BSA对牛主动脉内皮细胞（BAEC）也有毒性，使细胞数量减少至未处理对照的84±3.1%。在类似条件下，低浓度（62.5微克/毫升）的AGE-BSA对BREC有促有丝分裂作用，使细胞增殖比未处理对照增加至156±11%（p<0.05）。在500微克/毫升的较高剂量下，AGE-BSA使BREC的增殖减少至未处理对照的85±6%。免疫印迹分析表明，BRP和BREC表达p60 AGE受体。来自人类的视网膜毛细血管床对p60 AGE受体也呈阳性染色。添加0.25微克/毫升的p60 AGE受体抗体能够阻断AGE-BSA对BRP和BREC的作用。[125I]标记的AGE-BSA与细胞表面的结合水平在三种细胞类型中虽小但显著。BRP和BREC中放射性配体的内化池也有所增加，但远低于BAEC。在所有细胞类型中，[125I]标记的AGE-BSA的内化池比与细胞表面相关的量要大得多。在细胞与[125I]AGE-BSA孵育24小时的培养基中未检测到降解产物。添加p60 AGE受体可阻止[125I]标记的AGE-BSA与细胞表面的结合。这些结果表明，AGE修饰的蛋白质与膜结合的AGE受体之间的相互作用可能在糖尿病视网膜病变的发病机制中起重要作用。
