Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of chronic kidney disease. Here, we identified recessive mutations in the gene encoding the actin-binding protein advillin (AVIL) in 3 unrelated families with SRNS. While all AVIL mutations resulted in a marked loss of its actin-bundling ability, truncation of AVIL also disrupted colocalization with F-actin, thereby leading to impaired actin binding and severing. Additionally, AVIL colocalized and interacted with the phospholipase enzyme PLCE1 and with the ARP2/3 actin-modulating complex. Knockdown of AVIL in human podocytes reduced actin stress fibers at the cell periphery, prevented recruitment of PLCE1 to the ARP3-rich lamellipodia, blocked EGF-induced generation of diacylglycerol (DAG) by PLCE1, and attenuated the podocyte migration rate (PMR). These effects were reversed by overexpression of WT AVIL but not by overexpression of any of the 3 patient-derived AVIL mutants. The PMR was increased by overexpression of WT Avil or PLCE1, or by EGF stimulation; however, this increased PMR was ameliorated by inhibition of the ARP2/3 complex, indicating that ARP-dependent lamellipodia formation occurs downstream of AVIL and PLCE1 function. Together, these results delineate a comprehensive pathogenic axis of SRNS that integrates loss of AVIL function with alterations in the action of PLCE1, an established SRNS protein.

Background: Acute kidney injury (AKI) is a complication of coronavirus disease 2019 (COVID-19). The reported incidence of AKI, however, varies among studies. We aimed to evaluate the incidence of AKI and its association with mortality and morbidity in children infected with severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) who required hospital admission.Methods: This was a multicenter retrospective cohort study from three tertiary centers, which included children with confirmed COVID-19. All children were evaluated for AKI using the Kidney Disease Improving Global Outcomes (KDIGO) definition and staging.Results: Of 89 children included, 19 (21 %) developed AKI (52.6 % stage I). A high renal angina index score was correlated with severity of AKI. Also, multisystem inflammatory syndrome in children (MIS-C) was increased in children with AKI compared to those with normal kidney function (15 % vs. 1.5 %). Patients with AKI had significantly more pediatric intensive care admissions (PICU) (32 % vs. 2.8 %,p < 0.001) and mortality (42 % vs. 0 %,p < 0.001). However, AKI was not associated with prolonged hospitalization (58 % vs. 40 %,p = 0.163) or development of MIS-C (10.5 % vs. 1.4 %,p = 0.051). No patient in the AKI group required renal replacement therapy. Residual renal impairment at discharge occurred in 9 % of patients. This was significantly influenced by the presence of comorbidities, hypotension, hypoxia, heart failure, acute respiratory distress, hypernatremia, abnormal liver profile, high C-reactive protein, and positive blood culture.Conclusions: AKI occurred in one-fifth of children with SARS-CoV-2 infection requiring hospital admission, with one-third of those requiring PICU. AKI was associated with increased morbidity and mortality, and residual renal impairment at time of discharge.