Division of Nephrology, Zhongshan Hospital, Xiamen University, Xiamen, China.
Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
J Clin Invest. 2020 Oct 1;130(10):5523-5535. doi: 10.1172/JCI140155.
Using the Nephrotic Syndrome Study Network Consortium data set and other publicly available transcriptomic data sets, we identified retinoic acid receptor responder protein 1 (RARRES1) as a gene whose expression positively correlated with renal function decline in human glomerular disease. The glomerular expression of RARRES1, which is largely restricted to podocytes, increased in focal segmental glomerulosclerosis (FSGS) and diabetic kidney disease (DKD). TNF-α was a potent inducer of RARRES1 expression in cultured podocytes, and transcriptomic analysis showed the enrichment of cell death pathway genes with RARRES1 overexpression. The overexpression of RARRES1 indeed induced podocyte apoptosis in vitro. Notably, this effect was dependent on its cleavage in the extracellular domain, as the mutation of its cleavage site abolished the apoptotic effect. Mechanistically, the soluble RARRES1 was endocytosed and interacted with and inhibited RIO kinase 1 (RIOK1), resulting in p53 activation and podocyte apoptosis. In mice, podocyte-specific overexpression of RARRES1 resulted in marked glomerular injury and albuminuria, while the overexpression of RARRES1 cleavage mutant had no effect. Conversely, podocyte-specific knockdown of Rarres1 in mice ameliorated glomerular injury in the setting of adriamycin-induced nephropathy. Our study demonstrates an important role and the mechanism of RARRES1 in podocyte injury in glomerular disease.
利用肾病综合征研究网络联盟数据集和其他公开可用的转录组数据集,我们确定维甲酸受体应答蛋白 1 (RARRES1) 是一个基因,其表达与人类肾小球疾病肾功能下降呈正相关。RARRES1 的肾小球表达主要局限于足细胞,在局灶节段性肾小球硬化症 (FSGS) 和糖尿病肾病 (DKD) 中增加。TNF-α 是培养的足细胞中 RARRES1 表达的有效诱导剂,转录组分析显示细胞死亡途径基因与 RARRES1 过表达富集。RARRES1 的过表达确实在体外诱导了足细胞凋亡。值得注意的是,这种效应依赖于其在细胞外结构域的裂解,因为其裂解位点的突变消除了凋亡效应。在机制上,可溶性 RARRES1 被内吞,并与 RIOK1 相互作用并抑制 RIOK1,导致 p53 激活和足细胞凋亡。在小鼠中,足细胞特异性过表达 RARRES1 导致明显的肾小球损伤和白蛋白尿,而 RARRES1 裂解突变体的过表达则没有影响。相反,在阿霉素诱导的肾病小鼠中,足细胞特异性敲低 Rarres1 可改善肾小球损伤。我们的研究表明 RARRES1 在肾小球疾病中足细胞损伤中的重要作用和机制。