Advanced Glycated End-Products Affect HIF-Transcriptional Activity in Renal Cells
Advanced Glycated End-Products Affect HIF-Transcriptional Activity in Renal Cells
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DOI：
10.1210/me.2013-1036
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发表时间：
2013-11-01
影响因子：
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通讯作者：
Wolf, Gunter
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文献类型：
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作者：
Bondeva, Tzvetanka;Heinzig, Juliane;Wolf, Gunter
晚期糖化终末产物(AGEs)是AGEs受体的配体，在糖尿病疾病中增加。MAPK组织者1(Morg1)可能通过其结合伙伴Pro-羟基酶结构域(PhD-3)在低氧诱导因子-1α(HIF-1α)和HIF-2α转录激活中发挥作用。本研究的目的是分析AGEs对不同类型肾细胞Morg1表达的影响及其与PHD3活性和HIF转录活性的相关性。糖化牛血清白蛋白(AGE-BSA)显著上调小鼠肾小球系膜细胞Morg1mRNA水平，下调小鼠近端肾小管细胞和分化足细胞Morg1mRNA水平。当细胞与α-AGE抗体受体预先孵育时，这些效应是可逆的。与未糖化的对照-BSA相比，AGE-BSA处理导致Morg1细胞分布的重新定位。对PHD3活性的分析表明，加入AGE-BSA后，小鼠肾小球系膜细胞的PHD3酶活性升高，而小鼠近端肾小管细胞和足细胞的PHD3酶活性受到抑制。AGE-BSA处理对HIF转录活性也有影响。报告基因分析和EMSA分析表明，AGEs在非缺氧条件下以细胞类型特异性的方式调节HIF转录活性。在近端肾小管细胞中，AGE-BSA刺激主要增加HIF-1α转录活性，少量增加HIF-2α转录活性。我们还检测到Morg1杂合(HZ)安慰剂组小鼠肾脏中HIF-1α和HIF-2α蛋白的表达高于Morg1野生型(WT)安慰剂组小鼠，并且Morg1 HZ链脲佐菌素治疗组小鼠的HIF-1α蛋白表达显著高于WT链脲佐菌素治疗组小鼠。对Morg1、HZ(+/-)和WT小鼠分离的系膜细胞的分析表明，在只有一个Morg1等位基因的细胞中，PHD3活性受到抑制，HIF转录活性增加。这些发现对于更好地理解糖尿病肾病的分子机制具有重要意义。
Advanced glycated end-products (AGEs) are ligands of the receptor for AGEs and increase in diabetic disease. MAPK organizer 1 (Morg1) via its binding partner prolyl-hydroxylase domain (PHD)-3 presumably plays a role in the regulation of hypoxia-inducible factor (HIF)-1 alpha and HIF-2 alpha transcriptional activation. The purpose of this study was to analyze the influence of AGEs on Morg1 expression and its correlation to PHD3 activity and HIF-transcriptional activity in various renal cell types. The addition of glycated BSA (AGE-BSA) significantly up-regulated Morg1 mRNA levels in murine mesangial cells and down-regulated it in murine proximal tubular cells and differentiated podocytes. These effects were reversible when the cells were preincubated with a receptor for alpha-AGE antibody. AGE-BSA treatment induced a relocalization of the Morg1 cellular distribution compared with nonglycated control-BSA. Analysis of PHD3 activity demonstrated an elevated PHD3 enzymatic activity in murine mesangial cells but an inhibition in murine proximal tubular cells and podocytes after the addition of AGE-BSA. HIF-transcriptional activity was also affected by AGE-BSA treatment. Reporter gene assays and EMSAs showed that AGEs regulate HIF-transcriptional activity under nonhypoxic conditions in a cell type-specific manner. In proximal tubular cells, AGE-BSA stimulation elevated mainly HIF-1 alpha transcriptional activity and to a lesser extent HIF-2 alpha. We also detected an increased expression of the HIF-1 alpha and the HIF-2 alpha proteins in kidneys from Morg1 heterozygous (HZ) placebo mice compared with the Morg1 wild-type (WT) placebo-treated mice, and the HIF-1 alpha protein expression in the Morg1 HZ streptozotocin-treated mice was significantly higher than the WT streptozotocin-treated mice. Analysis of isolated mesangial cells from Morg1 HZ (+/-) and WT mice showed an inhibited PHD3 activity and an increased HIF-transcriptional activity in cells with only one Morg1 allele. These findings are important for a better understanding of the molecular mechanisms of diabetic nephropathy.