Novel splice variants of the receptor for advanced glycation end-products expressed in human vascular endothelial cells and pericytes, and their putative roles in diabetes-induced vascular injury
Novel splice variants of the receptor for advanced glycation end-products expressed in human vascular endothelial cells and pericytes, and their putative roles in diabetes-induced vascular injury
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DOI：
10.1042/bj20021371
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发表时间：
2003-03-15
影响因子：
4.1
通讯作者：
Yamamoto, H
中科院分区：
文献类型：
--
作者：
Yonekura, H;Yamamoto, Y;Yamamoto, H
已知晚期糖基化终产物（AGE）与AGE受体（AGEs）的结合使多种细胞功能恶化，并且与糖尿病血管并发症的发病机制有关。在本研究中，我们表明，小血管，内皮细胞（EC）和周细胞的细胞成分表达新的剪接变体的mRNA编码的亚型，缺乏N-末端V型免疫球蛋白样结构域（N-截短）或C-末端跨膜结构域（C-截短），以及已知的全长mRNA。三种变体的表达比例在EC和周细胞之间是不同的; C-截短形式的含量在EC中是最高的，而全长形式在周细胞中是最丰富的。COS-7细胞转染实验表明，这些变异的mRNA被翻译成蛋白质的推断; C-截短的cDNA被有效地分泌到培养基中，和N-截短的cDNA主要位于质膜上。在原代培养的人EC和周细胞中也检测到这三种亚型。此外，全长和C-截短形式的结合AGE共轭柱，而N-截短的结合没有。AGE诱导的细胞外信号相关激酶磷酸化和血管内皮生长因子在EC和EC的生长和索状结构的形成被完全废除由C-截短的β-内酰胺酶，表明这种内源性分泌受体（内源性分泌型β-内酰胺酶）对AGE具有细胞保护作用。这些结果可能有助于我们理解细胞对AGE反应的多样性和糖尿病血管并发症易感性的个体差异的分子基础。
The binding of advanced glycation end-products (AGE) to the receptor for AGE (RAGE) is known to deteriorate various cell functions and is implicated in the pathogenesis of diabetic vascular complications. In the present study, we show that the cellular constituents of small vessels, endothelial cells (EC) and pericytes express novel splice variants of RAGE mRNA coding for the isoforms that lack the N-terminal V-type immunoglobulin-like domain (N-truncated) or the C-terminal transmembrane domain (C-truncated), as well as the known full-length mRNA. The ratio of the expression of the three variants was different between EC and pericytes; the content of the C-truncated form was highest in EC, whereas the full-length form was the most abundant in pericytes. Transfection experiments with COS-7 cells demonstrated that those variant mRNAs were translated into proteins as deduced; C-truncated RAGE was efficiently secreted into the culture media, and N-truncated RAGE was located mainly on the plasma membrane. The three isoforms were also detected in primary cultured human EC and pericytes. Further, full-length and C-truncated forms of RAGE bound to an AGE-conjugated column, whereas N-truncated RAGE did not. The AGE induction of extracellular-signal-related kinase phosphorylation and vascular endothelial growth factor in EC and of the growth and cord-like structure formation of EC was abolished completely by C-truncated RAGE, indicating that this endogenous secretory receptor (endogenous secretory RAGE) is cytoprotective against AGE. The results may contribute to our understanding of the molecular basis for the diversity of cellular responses to AGE and for individual variations in the susceptibility to diabetic vascular complications.