Browsing by Author "Hall, Gentzon"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Open Access JAK inhibitor blocks COVID-19 cytokine-induced JAK/STAT/APOL1 signaling in glomerular cells and podocytopathy in human kidney organoids.(JCI insight, 2022-06) Nystrom, Sarah E; Li, Guojie; Datta, Somenath; Soldano, Karen L; Silas, Daniel; Weins, Astrid; Hall, Gentzon; Thomas, David B; Olabisi, Opeyemi ACOVID-19 infection causes collapse of glomerular capillaries and loss of podocytes, culminating in a severe kidney disease called COVID-19-associated nephropathy (COVAN). The underlying mechanism of COVAN is unknown. We hypothesized that cytokines induced by COVID-19 trigger expression of pathogenic APOL1 via JAK/STAT signaling, resulting in podocyte loss and COVAN phenotype. Here, based on 9 biopsy-proven COVAN cases, we demonstrated for the first time, to the best of our knowledge, that APOL1 protein was abundantly expressed in podocytes and glomerular endothelial cells (GECs) of COVAN kidneys but not in controls. Moreover, a majority of patients with COVAN carried 2 APOL1 risk alleles. We show that recombinant cytokines induced by SARS-CoV-2 acted synergistically to drive APOL1 expression through the JAK/STAT pathway in primary human podocytes, GECs, and kidney micro-organoids derived from a carrier of 2 APOL1 risk alleles, but expression was blocked by a JAK1/2 inhibitor, baricitinib. We demonstrate that cytokine-induced JAK/STAT/APOL1 signaling reduced the viability of kidney organoid podocytes but was rescued by baricitinib. Together, our results support the conclusion that COVID-19-induced cytokines are sufficient to drive COVAN-associated podocytopathy via JAK/STAT/APOL1 signaling and that JAK inhibitors could block this pathogenic process. These findings suggest JAK inhibitors may have therapeutic benefits for managing cytokine-induced, APOL1-mediated podocytopathy.Item Open Access Rare hereditary COL4A3/COL4A4 variants may be mistaken for familial focal segmental glomerulosclerosis.(Kidney Int, 2014-12) Malone, Andrew F; Phelan, Paul J; Hall, Gentzon; Cetincelik, Umran; Homstad, Alison; Alonso, Andrea S; Jiang, Ruiji; Lindsey, Thomas B; Wu, Guanghong; Sparks, Matthew A; Smith, Stephen R; Webb, Nicholas JA; Kalra, Philip A; Adeyemo, Adebowale A; Shaw, Andrey S; Conlon, Peter J; Jennette, J Charles; Howell, David N; Winn, Michelle P; Gbadegesin, Rasheed AFocal segmental glomerulosclerosis (FSGS) is a histological lesion with many causes, including inherited genetic defects, with significant proteinuria being the predominant clinical finding at presentation. Mutations in COL4A3 and COL4A4 are known to cause Alport syndrome (AS), thin basement membrane nephropathy, and to result in pathognomonic glomerular basement membrane (GBM) findings. Secondary FSGS is known to develop in classic AS at later stages of the disease. Here, we present seven families with rare or novel variants in COL4A3 or COL4A4 (six with single and one with two heterozygous variants) from a cohort of 70 families with a diagnosis of hereditary FSGS. The predominant clinical finding at diagnosis was proteinuria associated with hematuria. In all seven families, there were individuals with nephrotic-range proteinuria with histologic features of FSGS by light microscopy. In one family, electron microscopy showed thin GBM, but four other families had variable findings inconsistent with classical Alport nephritis. There was no recurrence of disease after kidney transplantation. Families with COL4A3 and COL4A4 variants that segregated with disease represent 10% of our cohort. Thus, COL4A3 and COL4A4 variants should be considered in the interpretation of next-generation sequencing data from such patients. Furthermore, this study illustrates the power of molecular genetic diagnostics in the clarification of renal phenotypes.Item Open Access Variability in phenotype induced by the podocin variant R229Q plus a single pathogenic mutation.(Clin Kidney J, 2015-10) Phelan, Paul J; Hall, Gentzon; Wigfall, Delbert; Foreman, John; Nagaraj, Shashi; Malone, Andrew F; Winn, Michelle P; Howell, David N; Gbadegesin, RasheedBACKGROUND: Mutations in podocin (NPHS2) are the most common cause of childhood onset autosomal recessive steroid-resistant nephrotic syndrome (SRNS). The disease is characterized by early-onset proteinuria, resistance to immunosuppressive therapy and rapid progression to end-stage renal disease. Compound heterozygous changes involving the podocin variant R229Q combined with another pathogenic mutation have been associated with a mild phenotype with disease onset often in adulthood. METHODS: We screened 19 families with early-onset SRNS for mutations in NPHS2 and WT1 and identified four disease-causing mutations (three in NPHS2 and one in WT1) prior to planned whole-exome sequencing. RESULTS: We describe two families with three individuals presenting in childhood who are compound heterozygous for R229Q and one other pathogenic NPHS2 mutation, either L327F or A297V. One child presented at age 4 years (A297V plus R229Q) and the other two at age 13 (L327F plus R229Q), one with steadily deteriorating renal function. CONCLUSIONS: These cases highlight the phenotypic variability associated with the NPHS2 R229Q variant plus pathogenic mutation. Individuals may present with early aggressive disease.