Li Hongyan, Liu Fang, Kuang Hanzhe, Teng Hua, Chen Siyi, Zeng Sijing, Zhou Qimin, Li Zhaokai, Liang Desheng, Li Zhuo, Wu Lingqian
Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics & Hunan Key Laboratory of Animal Models for Human Disease, School of Life Sciences, Central South University, Changsha 410000, China.
Biology (Basel). 2022 Sep 25;11(10):1397. doi: 10.3390/biology11101397.
(1) Background: Galloway-Mowat syndrome (GAMOS) is a rare genetic disease, classically characterized by a combination of various neurological symptoms and nephrotic syndrome. WDR73 is the pathogenic gene responsible for GAMOS1. However, the pathological and molecular mechanisms of GAMOS1, especially nephrotic syndrome caused by WDR73 deficiency, remain unknown. (2) Methods and Results: In this study, we first observed remarkable cellular morphological changes including impaired cell adhesion, decreased pseudopodia, and G2/M phase arrest in WDR73 knockout (KO) HEK 293 cells. The differentially expressed genes in WDR73 KO cells were enriched in the focal adhesion (FA) pathway. Additionally, PIP4K2C, a phospholipid kinase also involved in the FA pathway, was subsequently validated to interact with WDR73 via protein microarray and GST pulldown. WDR73 regulates PIP4K2C protein stability through the autophagy-lysosomal pathway. The stability of PIP4K2C was significantly disrupted by WDR73 KO, leading to a remarkable reduction in PIP2 and thus weakening the FA formation. In addition, we found that podocyte-specific conditional knockout (Wdr73 CKO) mice showed high levels of albuminuria and podocyte foot process injury in the ADR-induced model. FA formation was impaired in primary podocytes derived from Wdr73 CKO mice. (3) Conclusions: Since FA has been well known for its critical roles in maintaining podocyte structures and function, our study indicated that nephrotic syndrome in GAMOS1 is associated with disruption of FA caused by WDR73 deficiency.
(1) 背景：加洛韦 - 莫瓦特综合征（GAMOS）是一种罕见的遗传性疾病，典型特征为多种神经症状和肾病综合征的组合。WDR73是导致GAMOS1的致病基因。然而，GAMOS1的病理和分子机制，尤其是由WDR73缺乏引起的肾病综合征，仍不清楚。(2) 方法与结果：在本研究中，我们首先观察到WDR73基因敲除（KO）的HEK 293细胞出现显著的细胞形态变化，包括细胞黏附受损、伪足减少和G2/M期阻滞。WDR73 KO细胞中差异表达的基因在粘着斑（FA）途径中富集。此外，随后通过蛋白质微阵列和GST下拉实验验证了同样参与FA途径的磷脂激酶PIP4K2C与WDR73相互作用。WDR73通过自噬 - 溶酶体途径调节PIP4K2C蛋白稳定性。WDR73基因敲除显著破坏了PIP4K2C的稳定性，导致PIP2显著减少，从而削弱了粘着斑的形成。此外，我们发现足细胞特异性条件性敲除（Wdr73 CKO）小鼠在阿霉素诱导的模型中表现出高水平蛋白尿和足细胞足突损伤。源自Wdr73 CKO小鼠的原代足细胞中粘着斑形成受损。(3) 结论：由于粘着斑在维持足细胞结构和功能中的关键作用已广为人知，我们的研究表明GAMOS1中的肾病综合征与WDR73缺乏导致的粘着斑破坏有关。
