Dent disease 1 (DD1) is a rare X-linked renal proximal tubulopathy characterized by low molecular weight proteinuria (LMWP) and variable degree of hypercalciuria, nephrocalcinosis and/or nephrolithiasis with progression to chronic kidney disease (CKD). Although loss-of-function mutations in the gene CLCN5 encoding the electrogenic Cl-/H+ antiporter ClC-5, which impair endocytic uptake in proximal tubule cells, cause the disease, there is poor genotype-phenotype correlation and their contribution to proximal tubule dysfunction remains unclear. Here, in order to discover the mechanisms leading to proximal tubule dysfunction due to ClC-5 loss-of-function, we have generated and characterized new human cellular models of DD1 by silencing CLCN5 and introducing the ClC-5 pathogenic mutants V523del, E527D and I524K into the human proximal tubule-derived cell line RPTEC/TERT1. Depletion of CLCN5 or expression of mutant ClC-5 impairs albumin endocytosis, increases substrate adhesion and decreases collective migration, which correlates with a less differentiated epithelial phenotype. Interestingly, although all conditions compromised the endocytic capacity in a similar way, their impact on gene expression profiles was different. Our DNA microarray studies show that ClC-5 silencing or mutant re-introduction alter pathways related to nephron development, anion homeostasis, organic acid transport, extracellular matrix organization and cell migration, compared to control cells. Cells carrying the V523del ClC-5 mutation show the largest differences in gene expression vs WT cells, which is in agreement with the more aggressive clinical phenotype observed in some DD1 patients. Overall, this work emphasizes the use of human proximal tubule derived cell models to identify the molecular processes underlying ClC-5 deficiency.

中文翻译：

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全球基因表达分析揭示了在新型Dent Disease 1细胞模型中ClC-5功能丧失的分子过程

齿病1（DD1）是一种罕见的X连锁性肾近端肾小管病，其特征在于低分子量蛋白尿（LMWP）和不同程度的高钙尿，肾钙化和/或肾结石病，并发展为慢性肾脏病（CKD）。尽管编码致病性Cl- / H +反向转运蛋白ClC-5的基因CLCN5的功能丧失突变会损害近端小管细胞的内吞摄取，但会导致这种疾病，但基因型与表型的相关性较差，并且它们对近端小管功能障碍的影响还不清楚。在这里，为了发现由于ClC-5功能丧失导致近端肾小管功能障碍的机制，我们通过沉默CLCN5并引入ClC-5致病性突变体V523del，生成并表征了DD1的新人类细胞模型，E527D和I524K进入人近端小管衍生细胞系RPTEC / TERT1。CLCN5的耗竭或突变体ClC-5的表达损害白蛋白内吞，增加底物粘附并减少集体迁移，这与分化程度较低的上皮表型相关。有趣的是，尽管所有条件都以相似的方式损害了内吞能力，但它们对基因表达谱的影响却不同。我们的DNA微阵列研究表明，与对照细胞相比，ClC-5沉默或突变体的重新引入改变了与肾单位发育，阴离子稳态，有机酸转运，细胞外基质组织和细胞迁移有关的途径。与WT细胞相比，带有V523del ClC-5突变的细胞在基因表达上显示出最大的差异，这与在某些DD1患者中观察到的更具攻击性的临床表型一致。总的来说，这项工作强调使用人类近端肾小管衍生的细胞模型来识别ClC-5缺乏症的分子过程。