Transcriptional profiling of a mouse model of Uromodulin Associated Kidney Disease (UAKD)

Uromodulin (UMOD) is a secreted glycoprotein exclusively expressed by the cells lining the thick ascending limb of the loop of henle and the early distal tubule of the kidney nephron. Mutations in UMOD that interfere with proper folding of the protein are responsible for a progressive form of interstitial fibrotic kidney disease that leads to end stage renal disease, referred to as Uromodulin Associated Kidney Disease (UAKD). To assess key transcriptional changes associated with the progression of UAKD, we generated a knock-in mouse model harboring the mouse equivalent of the human mutation C148W. We profiled both the whole kidney tissue, as well as the specific UMOD+ cell populations in mutant and wild type mice. Analysis of differentially expressed genes in whole tissue and UMOD+ cells revealed a strong TNF-signaling signature, as well as TRIB3 upregulation, which is a key mediator of the intrinsic ER-stress mediated cell death pathway. Uromodulin mutant and wild type littermate controls were aged to 6, 12, 24, and 30 weeks of age. Total RNA was isolated from whole kidney tissue and from isolated, Uromodulin positive cells at each timepoint.尿调蛋白（Uromodulin, UMOD）是一种分泌型糖蛋白，仅由肾单位亨利袢粗升支及肾早期远端小管的内衬细胞表达。可干扰该蛋白正确折叠的UMOD基因突变，会引发一种进展性间质性纤维化肾病，最终可导致终末期肾病，该疾病被称为尿调蛋白相关性肾病（Uromodulin Associated Kidney Disease, UAKD）。为评估与UAKD进展相关的关键转录变化，我们构建了携带人类C148W突变对应小鼠突变位点的敲入小鼠模型。我们对突变型与野生型小鼠的全肾组织，以及特异性UMOD阳性细胞群进行了表达谱分析。对全组织及UMOD阳性细胞中的差异表达基因进行分析后，我们发现了显著的肿瘤坏死因子（Tumor Necrosis Factor, TNF）信号通路特征，同时还观察到TRIB3表达上调——TRIB3是内源性内质网应激介导的细胞死亡通路的关键介质。我们将尿调蛋白突变小鼠及野生型同窝对照小鼠分别饲养至6、12、24及30周龄。在每个时间点，我们均从全肾组织以及分离得到的UMOD阳性细胞中提取了总RNA。