受体megalin和cubilin介导白蛋白吸收的免疫组织化学研究

Immunofluoresent Evidence for the Uptake of Albumin Involving Megalin and Cubilin in Cultured Renal Proximal Tubule Cells

目的及方法 采用免疫荧光双标记技术对培养的opossum肾 (OK)细胞膜受体megalin和cubilin的表达及其与荧光标记的白蛋白摄取的关系进行研究。结果 不同荧光标记的受体megalin及cubilin同时表达在相同的OK细胞上 ,分布主要局限在细胞膜 ,而且形式相似。被摄取的荧光标记的白蛋白点状分布在OK细胞内。此外 ,有受体megalin和cubilin表达的细胞就有白蛋白的摄取 ;反之 ,既不表达受体megalin和cubilin的细胞 ,也没有白蛋白的摄取。结论 这种白蛋白的摄取与受体megalin和cubilin表达的特征提示 ,两种大分子糖蛋白受体megalin和cubilin与白蛋白的摄取有密切相关性 ,很可能在肾小管重吸收白蛋白中起到相互作用。

Objective and methods Using double labeled immunofluoresence microscopy we examined the colocalization of two giant glycoprotein receptors,megalin and cubilin,in cultured proximal tubule cells of opossum kidney(OK),and analyzed the relationship between uptake of albumin and expression of megalin or cubilin.Results An immunofluoresence microscope turned out the immunoreaction for megalin and cubilin was mainly located at the surface of OK cells,and they were identified in the same cells and with the same labeling pattern.Furthermore,the colocalization of fluorescence labeled albumin,megalin and cubilin were showed by a punctate labeling,representing endocytosed albumin in the cells that were also peripherally labeled for either megalin or cubilin.Conclusion The expression of megalin and cubilin and their correlation with uptake of albumin suggest that both megalin and cubilin might be involved in uptake of albumin.