1
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Kovalik ME, Dacanay MA, Crowley SD, Hall G. Swollen Feet: Considering the Paradoxical Roles of Interleukins in Nephrotic Syndrome. Biomedicines 2024; 12:738. [PMID: 38672094 PMCID: PMC11048099 DOI: 10.3390/biomedicines12040738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/11/2024] [Accepted: 03/15/2024] [Indexed: 04/28/2024] Open
Abstract
Interleukins are a family of 40 bioactive peptides that act through cell surface receptors to induce a variety of intracellular responses. While interleukins are most commonly associated with destructive, pro-inflammatory signaling in cells, some also play a role in promoting cellular resilience and survival. This review will highlight recent evidence of the cytoprotective actions of the interleukin 1 receptor (IL-1R)- and common gamma chain receptor (IL-Rγc)-signaling cytokines in nephrotic syndrome (NS). NS results from the injury or loss of glomerular visceral epithelial cells (i.e., podocytes). Although the causes of podocyte dysfunction vary, it is clear that pro-inflammatory cytokines play a significant role in regulating the propagation, duration and severity of disease. Pro-inflammatory cytokines signaling through IL-1R and IL-Rγc have been shown to exert anti-apoptotic effects in podocytes through the phosphoinositol-3-kinase (PI-3K)/AKT pathway, highlighting the potential utility of IL-1R- and IL-Rγc-signaling interleukins for the treatment of podocytopathy in NS. The paradoxical role of interleukins as drivers and mitigators of podocyte injury is complex and ill-defined. Emerging evidence of the cytoprotective role of some interleukins in NS highlights the urgent need for a nuanced understanding of their pro-survival benefits and reveals their potential as podocyte-sparing therapeutics for NS.
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Affiliation(s)
- Maria E. Kovalik
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
| | - Monique A. Dacanay
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
| | - Steven D. Crowley
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
| | - Gentzon Hall
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
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2
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Hall G, Lin J. Outscoring Current Classification Systems for Nephrotic Syndrome. Am J Kidney Dis 2022; 79:783-784. [PMID: 35153081 DOI: 10.1053/j.ajkd.2021.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/19/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Gentzon Hall
- Division of Nephrology, Department of Internal Medicine, Duke University School of Medicine, Durham, North Carolina; Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
| | - Jennie Lin
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.
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3
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Development of Biomarkers and Molecular Therapy Based on Inflammatory Genes in Diabetic Nephropathy. Int J Mol Sci 2021; 22:ijms22189985. [PMID: 34576149 PMCID: PMC8465809 DOI: 10.3390/ijms22189985] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 02/06/2023] Open
Abstract
Diabetic Nephropathy (DN) is a debilitating consequence of both Type 1 and Type 2 diabetes affecting the kidney and renal tubules leading to End Stage Renal Disease (ESRD). As diabetes is a world epidemic and almost half of diabetic patients develop DN in their lifetime, a large group of people is affected. Due to the complex nature of the disease, current diagnosis and treatment are not adequate to halt disease progression or provide an effective cure. DN is now considered a manifestation of inflammation where inflammatory molecules regulate most of the renal physiology. Recent advances in genetics and genomic technology have identified numerous susceptibility genes that are associated with DN, many of which have inflammatory functions. Based on their role in DN, we will discuss the current aspects of developing biomarkers and molecular therapy for advancing precision medicine.
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4
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Trionfini P, Ciampi O, Todeschini M, Ascanelli C, Longaretti L, Perico L, Remuzzi G, Benigni A, Tomasoni S. CRISPR-Cas9-Mediated Correction of the G189R-PAX2 Mutation in Induced Pluripotent Stem Cells from a Patient with Focal Segmental Glomerulosclerosis. CRISPR J 2020; 2:108-120. [PMID: 30998089 DOI: 10.1089/crispr.2018.0048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is defined by focal (involving few glomeruli) and segmental sclerosis of the glomerular tuft that manifests with nephrotic syndrome. Mutations in genes involved in the maintenance of structure and function of podocytes have been found in a minority of these patients. A family with adult-onset autosomal dominant FSGS was recently found to carry a new germline missense heterozygous mutation (p.G189R) in the octapeptide domain of the transcription factor PAX2. Here, we efficiently corrected this point mutation in patient-derived induced pluripotent stem cells (iPSCs) by means of CRISPR-Cas9-based homology-directed repair. The iPSC lines were differentiated into podocytes, which were tested for their motility. Editing the PAX2 p.G189R mutation restored podocyte motility, which was altered in podocytes derived from patient iPSCs.
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Affiliation(s)
- Piera Trionfini
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Osele Ciampi
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Marta Todeschini
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Camilla Ascanelli
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Lorena Longaretti
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Luca Perico
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Giuseppe Remuzzi
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy.,2 L. Sacco' Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Ariela Benigni
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
| | - Susanna Tomasoni
- 1 Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy; University of Milan, Milan, Italy
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5
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Wang L, Chang JH, Buckley AF, Spurney RF. Knockout of TRPC6 promotes insulin resistance and exacerbates glomerular injury in Akita mice. Kidney Int 2020; 95:321-332. [PMID: 30665571 DOI: 10.1016/j.kint.2018.09.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/22/2018] [Accepted: 09/27/2018] [Indexed: 12/17/2022]
Abstract
Gain-of-function mutations in TRPC6 cause familial focal segmental glomerulosclerosis, and TRPC6 is upregulated in glomerular diseases including diabetic kidney disease. We studied the effect of systemic TRPC6 knockout in the Akita model of type 1 diabetes. Knockout of TRPC6 inhibited albuminuria in Akita mice at 12 and 16 weeks of age, but this difference disappeared by 20 weeks. Knockout of TRPC6 also reduced tubular injury in Akita mice; however, mesangial expansion was significantly increased. Hyperglycemia and blood pressure were similar between TRPC6 knockout and wild-type Akita mice, but knockout mice were more insulin resistant. In cultured podocytes, knockout of TRPC6 inhibited expression of the calcium/calcineurin responsive gene insulin receptor substrate 2 and decreased insulin responsiveness. Insulin resistance is reported to promote diabetic kidney disease independent of blood glucose levels. While the mechanisms are not fully understood, insulin activates both Akt2 and ERK, which inhibits apoptosis signal regulated kinase 1 (ASK1)-p38-induced apoptosis. In cultured podocytes, hyperglycemia stimulated p38 signaling and induced apoptosis, which was reduced by insulin and ASK1 inhibition and enhanced by Akt or ERK inhibition. Glomerular p38 signaling was increased in TRPC6 knockout Akita mice and was associated with enhanced expression of the p38 gene target cyclooxygenase 2. These data suggest that knockout of TRPC6 in Akita mice promotes insulin resistance and exacerbates glomerular disease independent of hyperglycemia.
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Affiliation(s)
- Liming Wang
- Division of Nephrology, Department of Medicine, Duke University Health System, Durham, North Carolina, USA
| | - Jae-Hyung Chang
- Division of Nephrology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Anne F Buckley
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, USA
| | - Robert F Spurney
- Division of Nephrology, Department of Medicine, Duke University Health System, Durham, North Carolina, USA; Durham VA Medical Center, Durham, North Carolina, USA.
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6
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Reynolds BC, Oswald RJA. Diagnostic and Management Challenges in Congenital Nephrotic Syndrome. PEDIATRIC HEALTH MEDICINE AND THERAPEUTICS 2019; 10:157-167. [PMID: 31908565 PMCID: PMC6930517 DOI: 10.2147/phmt.s193684] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/05/2019] [Indexed: 12/21/2022]
Abstract
Congenital Nephrotic Syndrome (CNS) is defined as nephrotic range proteinuria, hypoalbuminaemia and edema in the first three months of life. CNS is most commonly genetic in cause, with international variance in the incidence of causative mutations. Initially defined by the histopathological appearance, increasingly sophisticated and accessible genetic analyses now provide a body of evidence to suggest that there is a disparity between the histological appearance, the genotype of individuals and the severity of the clinical disease. Through the evolution of management approaches CNS has changed from being an invariably fatal condition to one with appreciable ongoing morbidity and mortality but comparably good outcomes to other causes of paediatric end-stage renal disease, especially following transplantation. This review briefly summarises the more commonly recognised genetic mutations leading to CNS, addresses common management decisions, and concludes with potential therapies for the future.
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7
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Bensimhon AR, Williams AE, Gbadegesin RA. Treatment of steroid-resistant nephrotic syndrome in the genomic era. Pediatr Nephrol 2019; 34:2279-2293. [PMID: 30280213 PMCID: PMC6445770 DOI: 10.1007/s00467-018-4093-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 12/25/2022]
Abstract
The pathogenesis of steroid-resistant nephrotic syndrome (SRNS) is not completely known. Recent advances in genomics have elucidated some of the molecular mechanisms and pathophysiology of the disease. More than 50 monogenic causes of SRNS have been identified; however, these genes are responsible for only a small fraction of SRNS in outbred populations. There are currently no guidelines for genetic testing in SRNS, but evidence from the literature suggests that testing should be guided by the genetic architecture of the disease in the population. Notably, most genetic forms of SRNS do not respond to current immunosuppressive therapies; however, a small subset of patients with monogenic SRNS will achieve partial or complete remission with specific immunomodulatory agents, presumably due to non-immunosuppressive effects of these agents. We suggest a pragmatic approach to the therapy of genetic SRNS, as there is no evidence-based algorithm for the management of the disease.
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Affiliation(s)
- Adam R. Bensimhon
- Department of Pediatrics, Division of Nephrology, Duke University Medical Center, Durham, NC 27710, USA
| | - Anna E. Williams
- Department of Pediatrics, Division of Nephrology, Duke University Medical Center, Durham, NC 27710, USA
| | - Rasheed A. Gbadegesin
- Department of Pediatrics, Division of Nephrology, Duke University Medical Center, Durham, NC 27710, USA,Department of Medicine, Division of Nephrology, Duke University Medical Center, Durham, NC 27710, USA,Duke Molecular Physiology Institute, Durham, NC, USA
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8
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Anigilaje EA, Olutola A. Prospects of genetic testing for steroid-resistant nephrotic syndrome in Nigerian children: a narrative review of challenges and opportunities. Int J Nephrol Renovasc Dis 2019; 12:119-136. [PMID: 31190951 PMCID: PMC6512787 DOI: 10.2147/ijnrd.s193874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prevalence of childhood steroid-resistant nephrotic syndrome (SRNS) ranges from 35% to 92%. This steroid resistance among Nigerian children also reflects underlying renal histopathology, revealing a rare minimal-change disease and a varying burden of membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis (FSGS). FSGS tends to progress to end-stage kidney disease, which requires dialysis and/or renal transplantation. While knowledge of the molecular basis of NS is evolving, recent data support the role of mutant genes that otherwise maintain the structural and functional composition of the glomerular filtration barrier to account for many monogenic forms of FSGS. With the advent of next-generation sequencing, >39 genes are currently associated with SRNS, and the number is likely to increase in the near future. Monogenic FSGS is primarily resistant to steroids, and this foreknowledge obviates the need for steroids, other immunosuppressive therapy, and renal biopsy. Therefore, a multidisciplinary collaboration among cell biologists, molecular physiologists, geneticists, and clinicians holds prospects of fine-tuning the management of SRNS caused by known mutant genes. This article describes the genetics of NS/SRNS in childhood and also gives a narrative review of the challenges and opportunities for molecular testing among children with SRNS in Nigeria. For these children to benefit from genetic diagnosis, Nigeria must aspire to have and develop the manpower and infrastructure required for medical genetics and genomic medicine, leveraging on her existing experiences in genomic medicine. Concerted efforts can be put in place to increase the number of enrollees in Nigeria’s National Health Insurance Scheme (NHIS). The scope of the NHIS can be expanded to cater for the expensive bill of genetic testing within or outside the structure of the National Renal Care Policy proposed by Nigerian nephrologists.
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Affiliation(s)
- Emmanuel Ademola Anigilaje
- Nephrology Unit, Department of Paediatrics, Faculty of Clinical Sciences, College of Health Sciences, University of Abuja, Abuja, Nigeria,
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9
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Hall G, Lane BM, Khan K, Pediaditakis I, Xiao J, Wu G, Wang L, Kovalik ME, Chryst-Stangl M, Davis EE, Spurney RF, Gbadegesin RA. The Human FSGS-Causing ANLN R431C Mutation Induces Dysregulated PI3K/AKT/mTOR/Rac1 Signaling in Podocytes. J Am Soc Nephrol 2018; 29:2110-2122. [PMID: 30002222 PMCID: PMC6065096 DOI: 10.1681/asn.2017121338] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/31/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND We previously reported that mutations in the anillin (ANLN) gene cause familial forms of FSGS. ANLN is an F-actin binding protein that modulates podocyte cell motility and interacts with the phosphoinositide 3-kinase (PI3K) pathway through the slit diaphragm adaptor protein CD2-associated protein (CD2AP). However, it is unclear how the ANLN mutations cause the FSGS phenotype. We hypothesized that the R431C mutation exerts its pathogenic effects by uncoupling ANLN from CD2AP. METHODS We conducted in vivo complementation assays in zebrafish to determine the effect of the previously identified missense ANLN variants, ANLNR431C and ANLNG618C during development. We also performed in vitro functional assays using human podocyte cell lines stably expressing wild-type ANLN (ANLNWT ) or ANLNR431C . RESULTS Experiments in anln-deficient zebrafish embryos showed a loss-of-function effect for each ANLN variant. In human podocyte lines, expression of ANLNR431C increased cell migration, proliferation, and apoptosis. Biochemical characterization of ANLNR431C -expressing podocytes revealed hyperactivation of the PI3K/AKT/mTOR/p70S6K/Rac1 signaling axis and activation of mTOR-driven endoplasmic reticulum stress in ANLNR431C -expressing podocytes. Inhibition of mTOR, GSK-3β, Rac1, or calcineurin ameliorated the effects of ANLNR431C . Additionally, inhibition of the calcineurin/NFAT pathway reduced the expression of endogenous ANLN and mTOR. CONCLUSIONS The ANLNR431C mutation causes multiple derangements in podocyte function through hyperactivation of PI3K/AKT/mTOR/p70S6K/Rac1 signaling. Our findings suggest that the benefits of calcineurin inhibition in FSGS may be due, in part, to the suppression of ANLN and mTOR. Moreover, these studies illustrate that rational therapeutic targets for familial FSGS can be identified through biochemical characterization of dysregulated podocyte phenotypes.
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Affiliation(s)
- Gentzon Hall
- Departments of Pediatrics and
- Duke Molecular Physiology Institute, Durham, North Carolina; and
- Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Brandon M Lane
- Departments of Pediatrics and
- Duke Molecular Physiology Institute, Durham, North Carolina; and
| | - Kamal Khan
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina
| | - Igor Pediaditakis
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina
| | - Jianqiu Xiao
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina
| | - Guanghong Wu
- Departments of Pediatrics and
- Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Liming Wang
- Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Maria E Kovalik
- Departments of Pediatrics and
- Duke Molecular Physiology Institute, Durham, North Carolina; and
- Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Megan Chryst-Stangl
- Departments of Pediatrics and
- Duke Molecular Physiology Institute, Durham, North Carolina; and
| | - Erica E Davis
- Departments of Pediatrics and
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina
| | - Robert F Spurney
- Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Rasheed A Gbadegesin
- Departments of Pediatrics and
- Duke Molecular Physiology Institute, Durham, North Carolina; and
- Medicine, Duke University School of Medicine, Durham, North Carolina
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10
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Varner JD, Chryst-Stangl M, Esezobor CI, Solarin A, Wu G, Lane B, Hall G, Abeyagunawardena A, Matory A, Hunley TE, Lin JJ, Howell D, Gbadegesin R. Genetic Testing for Steroid-Resistant-Nephrotic Syndrome in an Outbred Population. Front Pediatr 2018; 6:307. [PMID: 30406062 PMCID: PMC6204400 DOI: 10.3389/fped.2018.00307] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/01/2018] [Indexed: 12/12/2022] Open
Abstract
Background: Steroid-resistant nephrotic syndrome (SRNS) is a leading cause of end-stage kidney disease in children and young adults. Despite advances in genomic science that have led to the discovery of >50 monogenic causes of SRNS, there are no clear guidelines for genetic testing in clinical practice. Methods: Using high throughput sequencing, we evaluated 492 individuals from 181 families for mutations in 40 known SRNS genes. Causative mutations were defined as missense, truncating, and obligatory splice site variants with a minor allele frequency <1% in controls. Non-synonymous variants were considered pathogenic if determined to be deleterious by at least two in silico models. We further evaluated for differences in age at disease onset, family history of SRNS or chronic kidney disease, race, sex, renal biopsy findings, and extra-renal manifestations in subgroups with and without disease causing variants. Results: We identified causative variants in 40 of 181 families (22.1%) with SRNS. Variants in INF2, COL4A3, and WT1 were the most common, accounting for over half of all causative variants. Causative variants were identified in 34 of 86 families (39.5%) with familial disease and 6 of 95 individuals (6.3%) with sporadic disease (χ2 p < 0.00001). Family history was the only significant clinical predictor of genetic SRNS. Conclusion: We identified causative mutations in almost 40% of all families with hereditary SRNS and 6% of individuals with sporadic disease, making family history the single most important clinical predictors of monogenic SRNS. We recommend genetic testing in all patients with SRNS and a positive family history, but only selective testing in those with sporadic disease.
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Affiliation(s)
- Jennifer D Varner
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
| | - Megan Chryst-Stangl
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
| | | | - Adaobi Solarin
- Department of Pediatrics, Lagos State University Teaching Hospital, Ikeja, Nigeria
| | - Guanghong Wu
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
| | - Brandon Lane
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
| | - Gentzon Hall
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
| | | | - Ayo Matory
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States
| | - Tracy E Hunley
- Division of Nephrology, Department of Pediatrics, Vanderbilt University, Nashville, TN, United States
| | - Jen Jar Lin
- Department of Pediatrics, Wake Forest Baptist Medical Center, Winston Salem, NC, United States
| | - David Howell
- Department of Pathology, Duke University Medical Center, Durham, NC, United States
| | - Rasheed Gbadegesin
- Division of Nephrology, Departments of Pediatrics and Medicine, Duke University Medical Center, Durham, NC, United States.,Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
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11
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Zhang H, Wang F, Liu X, Zhong X, Yao Y, Xiao H. Steroid-resistant nephrotic syndrome caused by co-inheritance of mutations at NPHS1 and ADCK4 genes in two Chinese siblings. Intractable Rare Dis Res 2017; 6:299-303. [PMID: 29259860 PMCID: PMC5735285 DOI: 10.5582/irdr.2017.01037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Hereditary nephrotic syndrome often presents with steroid-resistance and onset within the first year of life. Mutations in genes highly expressed in podocytes have been found in two thirds of these patients, especially NPHS1 and NPHS2 among at least 29 genetic causes that have been discovered. We reported two siblings with steroid-resistant nephrotic syndrome caused by co-inheritance of mutations at NPHS1 (c.1339G>A, p.E447K) and ACDK4 (c.748G>C, p.D250H) genes. The siblings presented with steroid-resistant nephrotic syndrome and pathological lesions of focal segmental glomerulosclerosis (FSGS), while the elder sister also developed hypertension, renal failure and cardiac dysfunction.
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Affiliation(s)
- Hongwen Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Fang Wang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Xiaoyu Liu
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Xuhui Zhong
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Yong Yao
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Huijie Xiao
- Department of Pediatric, Peking University First Hospital, Beijing, China
- Address correspondence to: Dr. Huijie Xiao, Department of Pediatric, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China. E-mail:
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12
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13
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Hall G, Routh JC, Gbadegesin RA. Urinary Anomalies in 22q11.2 Deletion (DiGeorge syndrome): From Copy Number Variations to Single-Gene Determinants of Phenotype. Am J Kidney Dis 2017; 70:8-10. [PMID: 28456345 DOI: 10.1053/j.ajkd.2017.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 03/06/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Gentzon Hall
- Duke University School of Medicine and Duke University Medical Center, Durham, North Carolina
| | - Jonathan C Routh
- Duke University School of Medicine and Duke University Medical Center, Durham, North Carolina
| | - Rasheed A Gbadegesin
- Duke University School of Medicine and Duke University Medical Center, Durham, North Carolina.
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14
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Crawford BD, Gillies CE, Robertson CC, Kretzler M, Otto EA, Vega-Warner V, Sampson MG. Evaluating Mendelian nephrotic syndrome genes for evidence for risk alleles or oligogenicity that explain heritability. Pediatr Nephrol 2017; 32:467-476. [PMID: 27766458 PMCID: PMC5483602 DOI: 10.1007/s00467-016-3513-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/25/2016] [Accepted: 08/29/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND More than 30 genes can harbor rare exonic variants sufficient to cause nephrotic syndrome (NS), and the number of genes implicated in monogenic NS continues to grow. However, outside the first year of life, the majority of affected patients, particularly in ancestrally mixed populations, do not have a known monogenic form of NS. Even in those children classified with a monogenic form of NS, there is phenotypic heterogeneity. Thus, we have only discovered a fraction of the heritability of NS-the underlying genetic factors contributing to phenotypic variation. Part of the "missing heritability" for NS has been posited to be explained by patients harboring coding variants across one or more previously implicated NS genes, insufficient to cause NS in a classical Mendelian manner, but that nonetheless have a sufficient impact on protein function to cause disease. However, systematic evaluation in patients with NS for rare or low-frequency risk alleles within single genes, or in combination across genes ("oligogenicity"), has not been reported. To determine whether, compared with a reference population, patients with NS have either a significantly increased burden of protein-altering variants ("risk-alleles"), or a unique combination of them ("oligogenicity"), in a set of 21 genes implicated in Mendelian forms of NS. METHODS In 303 patients with NS enrolled in the Nephrotic Syndrome Study Network (NEPTUNE), we performed targeted amplification paired with next-generation sequencing of 21 genes implicated in monogenic NS. We created a high-quality variant call set and compared it with a variant call set of the same genes in a reference population composed of 2,535 individuals from phase 3 of the 1000 Genomes Project. We created both a "stringent" and a "relaxed" pathogenicity-filtering pipeline, applied them to both cohorts, and computed the burden of variants in the entire gene set per cohort, the burden of variants in the entire gene set per individual, the burden of variants within a single gene per cohort, and unique combinations of variants across two or more genes per cohort. RESULTS With few exceptions when using the relaxed filter, and which are likely the result of confounding by population stratification, NS patients did not have a significantly increased burden of variants in Mendelian NS genes in comparison to a reference cohort, nor was there any evidence for oligogenicity. This was true when using both the relaxed and the stringent variant pathogenicity filter. CONCLUSION In our study, there were no significant differences in the burden or particular combinations of low-frequency or rare protein-altering variants in a previously implicated Mendelian NS genes cohort between North American patients with NS and a reference population. Studies in larger independent cohorts or meta-analyses are needed to assess the generalizability of our discoveries and also address whether there is in fact small but significant enrichment of risk alleles or oligogenicity in NS cases that was undetectable with this current sample size. It is still possible that rare protein-altering variants in these genes, insufficient to cause Mendelian disease, still contribute to NS as risk alleles and/or via oligogenicity. However, we suggest that more accurate bioinformatic analyses and the incorporation of functional assays would be necessary to identify bona fide instances of this form of genetic architecture as a contributor to the heritability of NS.
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Affiliation(s)
- Brendan D Crawford
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Christopher E Gillies
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Catherine C Robertson
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Matthias Kretzler
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Edgar A Otto
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Virginia Vega-Warner
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Matthew G Sampson
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA.
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Becherucci F, Mazzinghi B, Provenzano A, Murer L, Giglio S, Romagnani P. Lessons from genetics: is it time to revise the therapeutic approach to children with steroid-resistant nephrotic syndrome? J Nephrol 2016; 29:543-50. [DOI: 10.1007/s40620-016-0315-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/29/2016] [Indexed: 11/30/2022]
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16
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Teoh CW, Robinson LA, Noone D. Perspectives on edema in childhood nephrotic syndrome. Am J Physiol Renal Physiol 2015; 309:F575-82. [PMID: 26290369 DOI: 10.1152/ajprenal.00229.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/11/2015] [Indexed: 12/21/2022] Open
Abstract
There have been two major theories surrounding the development of edema in nephrotic syndrome (NS), namely, the under- and overfill hypotheses. Edema is one of the cardinal features of NS and remains one of the principal reasons for admission of children to the hospital. Recently, the discovery that proteases in the glomerular filtrate of patients with NS are activating the epithelial sodium channel (ENaC), resulting in intrarenal salt retention and thereby contributing to edema, might suggest that targeting ENaC with amiloride might be a suitable strategy to manage the edema of NS. Other potential agents, particularly urearetics and aquaretics, might also prove useful in NS. Recent evidence also suggests that there may be other areas involved in salt storage, especially the skin, and it will be intriguing to study the implications of this in NS.
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Affiliation(s)
- Chia Wei Teoh
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lisa A Robinson
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Damien Noone
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada
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