RNA-seq analysis of glycosylation related gene expression in STZ-induced diabetic rat kidney inner medulla.
RNA-seq analysis of glycosylation related gene expression in STZ-induced diabetic rat kidney inner medulla.
复制标题
STZ诱导糖尿病大鼠肾内髓质糖基化相关基因表达的RNA-seq分析
DOI：
10.3389/fphys.2015.00274
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发表时间：
2015
影响因子：
4
通讯作者：
Chen G
中科院分区：
文献类型：
--
作者：
Qian X;Li X;Ilori TO;Klein JD;Hughey RP;Li CJ;Alli AA;Guo Z;Yu P;Song X;Chen G
UT-A1尿素转运蛋白对肾脏产生浓缩尿的能力至关重要。来自肾脏内髓质（IM）的天然UT-A1是一种高度糖基化的蛋白质，具有97和117 kDa的两种糖基化形式。在糖尿病中，UT-A1蛋白丰度，特别是117 kD同种型，显著增加，对应于灌注的IM集合管中增加的尿素渗透性，这在防止由糖尿引起的渗透性利尿中起重要作用。然而，聚糖碳水化合物结构的变化和聚糖相关酶如何调节肾脏尿素转运活性，特别是在糖尿病条件下，在很大程度上是未知的。在这项研究中，使用糖特异性结合凝集素，我们发现UT-A1的碳水化合物结构随着唾液酸，岩藻糖的增加而改变，并且在糖尿病条件下增加聚糖分支。这些变化伴随着UT-A1与半乳糖凝集素蛋白、β-半乳糖苷聚糖结合蛋白的结合改变。为了探讨糖链结构改变的分子基础，采用高灵敏度的下一代测序技术Illumina RNA-seq，对链脲佐菌素（STZ）诱导的糖尿病大鼠肾脏UT-A1糖基化过程中的相关基因进行了分析。基因差异表达分析结合定量PCR技术揭示了糖尿病状态下糖基化相关基因的表达发生了变化。这些基因包括糖基转移酶基因Mgat 4a、唾液酸化酶St 3gal 1和St 3gal 4以及聚糖结合蛋白半乳糖凝集素-3、半乳糖凝集素-5、半乳糖凝集素-8和半乳糖凝集素-9。相比之下，虽然在肾脏IM中高度表达，但糖基转移酶基因Mgat 1、Mgat 2和岩藻糖基转移酶Fut 8未显示出任何变化。结论：在糖尿病中，不仅UT-A1蛋白丰度增加，而且蛋白的聚糖结构也发生了显着变化。UT-A1蛋白变得高度唾液酸化、岩藻糖基化和分支化。因此，许多关键的糖基化相关基因在糖尿病条件下发生改变。这些基因的改变可能导致UT-A1聚糖结构的变化，从而调节肾脏尿素转运活性，减轻糖尿病中由糖尿引起的渗透性利尿。
The UT-A1 urea transporter is crucial to the kidney's ability to generate concentrated urine. Native UT-A1 from kidney inner medulla (IM) is a heavily glycosylated protein with two glycosylation forms of 97 and 117 kDa. In diabetes, UT-A1 protein abundance, particularly the 117 kD isoform, is significantly increased corresponding to an increased urea permeability in perfused IM collecting ducts, which plays an important role in preventing the osmotic diuresis caused by glucosuria. However, how the glycan carbohydrate structure change and the glycan related enzymes regulate kidney urea transport activity, particularly under diabetic condition, is largely unknown. In this study, using sugar-specific binding lectins, we found that the carbohydrate structure of UT-A1 is changed with increased amounts of sialic acid, fucose, and increased glycan branching under diabetic conditions. These changes were accompanied by altered UT-A1 association with the galectin proteins, β-galactoside glycan binding proteins. To explore the molecular basis of the alterations of glycan structures, the highly sensitive next generation sequencing (NGS) technology, Illumina RNA-seq, was employed to analyze genes involved in the process of UT-A1 glycosylation using streptozotocin (STZ)—induced diabetic rat kidney. Differential gene expression analysis combining with quantitative PCR revealed that expression of a number of important glycosylation related genes were changed under diabetic conditions. These genes include the glycosyltransferase genes Mgat4a, the sialylation enzymes St3gal1 and St3gal4 and glycan binding protein galectin-3, -5, -8, and -9. In contrast, although highly expressed in kidney IM, the glycosyltransferase genes Mgat1, Mgat2, and fucosyltransferase Fut8, did not show any changes. Conclusions: In diabetes, not only is UT-A1 protein abundance increased but the protein's glycan structure is also significantly changed. UT-A1 protein becomes highly sialylated, fucosylated and branched. Consistently, a number of crucial glycosylation related genes are changed under diabetic conditions. The alteration of these genes may contribute to changes in the UT-A1 glycan structure and therefore modulate kidney urea transport activity and alleviate osmotic diuresis caused by glucosuria in diabetes.