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Lucas A, Wyatt CM. HIV at 40: kidney disease in HIV treatment, prevention, and cure. Kidney Int 2022; 102:740-749. [PMID: 35850290 PMCID: PMC9509437 DOI: 10.1016/j.kint.2022.06.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/06/2022] [Accepted: 06/03/2022] [Indexed: 10/17/2022]
Abstract
Four decades after the first cases of HIV were reported, kidney disease remains an important comorbidity in people with HIV (PWH). Both HIV-associated nephropathy and immune complex kidney disease were recognized as complications of HIV infection in the early years before treatment was available. Although the introduction of effective antiretroviral therapy in the late 1990s resulted in dramatic improvements in survival and health in PWH, several commonly used antiretroviral agents have been associated with kidney injury. HIV infection and treatment may also promote the progression of comorbid chronic kidney disease due to traditional risk factors such as diabetes, and HIV is one of the strongest "second hits" for the high-risk APOL1 genotype. Unique considerations in the management of chronic kidney disease in PWH are largely related to the need for lifelong antiretroviral therapy, with potential for toxicity, drug-drug interactions, and polypharmacy. PWH who develop progressive chronic kidney disease are candidates for all modalities of kidney replacement therapy, including kidney transplantation, and at some centers, PWH may be candidates to serve as donors for recipients with HIV. Transplantation of kidney allografts from donors with HIV also offers a unique opportunity to study viral dynamics in the kidney, with implications for kidney health and for research toward HIV cure. In addition, HIV-transgenic animal models have provided important insights into kidney disease pathogenesis beyond HIV, and experience with HIV and HIV-related kidney disease has provided important lessons for future pandemics.
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Affiliation(s)
- Anika Lucas
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Christina M Wyatt
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina, USA.
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Steers NJ, Gupta Y, D’Agati VD, Lim TY, DeMaria N, Mo A, Liang J, Stevens KO, Ahram DF, Lam WY, Gagea M, Nagarajan L, Sanna-Cherchi S, Gharavi AG. GWAS in Mice Maps Susceptibility to HIV-Associated Nephropathy to the Ssbp2 Locus. J Am Soc Nephrol 2022; 33:108-120. [PMID: 34893534 PMCID: PMC8763192 DOI: 10.1681/asn.2021040543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/27/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND To gain insight into the pathogenesis of collapsing glomerulopathy, a rare form of FSGS that often arises in the setting of viral infections, we performed a genome-wide association study (GWAS) among inbred mouse strains using a murine model of HIV-1 associated nephropathy (HIVAN). METHODS We first generated F1 hybrids between HIV-1 transgenic mice on the FVB/NJ background and 20 inbred laboratory strains. Analysis of histology, BUN, and urinary NGAL demonstrated marked phenotypic variation among the transgenic F1 hybrids, providing strong evidence for host genetic factors in the predisposition to nephropathy. A GWAS in 365 transgenic F1 hybrids generated from these 20 inbred strains was performed. RESULTS We identified a genome-wide significant locus on chromosome 13-C3 and multiple additional suggestive loci. Crossannotation of the Chr. 13 locus, including single-cell transcriptomic analysis of wildtype and HIV-1 transgenic mouse kidneys, nominated Ssbp2 as the most likely candidate gene. Ssbp2 is highly expressed in podocytes, encodes a transcriptional cofactor that interacts with LDB1 and LMX1B, which are both previously implicated in FSGS. Consistent with these data, older Ssbp2 null mice spontaneously develop glomerulosclerosis, tubular casts, interstitial fibrosis, and inflammation, similar to the HIVAN mouse model. CONCLUSIONS These findings demonstrate the utility of GWAS in mice to uncover host genetic factors for rare kidney traits and suggest Ssbp2 as susceptibility gene for HIVAN, potentially acting via the LDB1-LMX1B transcriptional network.
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Affiliation(s)
- Nicholas J. Steers
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Yask Gupta
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Vivette D. D’Agati
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York
| | - Tze Y. Lim
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Natalia DeMaria
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Anna Mo
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Judy Liang
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Kelsey O. Stevens
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Dina F. Ahram
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Wan Yee Lam
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Mihai Gagea
- Department of Veterinary Medicine and Surgery, University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Lalitha Nagarajan
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Simone Sanna-Cherchi
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Ali G. Gharavi
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
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Lack of APOL1 in proximal tubules of normal human kidneys and proteinuric APOL1 transgenic mouse kidneys. PLoS One 2021; 16:e0253197. [PMID: 34138902 PMCID: PMC8211208 DOI: 10.1371/journal.pone.0253197] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/30/2021] [Indexed: 11/19/2022] Open
Abstract
The mechanism of pathogenesis associated with APOL1 polymorphisms and risk for non-diabetic chronic kidney disease (CKD) is not fully understood. Prior studies have minimized a causal role for the circulating APOL1 protein, thus efforts to understand kidney pathogenesis have focused on APOL1 expressed in renal cells. Of the kidney cells reported to express APOL1, the proximal tubule expression patterns are inconsistent in published reports, and whether APOL1 is synthesized by the proximal tubule or possibly APOL1 protein in the blood is filtered and reabsorbed by the proximal tubule remains unclear. Using both protein and mRNA in situ methods, the kidney expression pattern of APOL1 was examined in normal human and APOL1 bacterial artificial chromosome transgenic mice with and without proteinuria. APOL1 protein and mRNA was detected in podocytes and endothelial cells, but not in tubular epithelia. In the setting of proteinuria, plasma APOL1 protein did not appear to be filtered or reabsorbed by the proximal tubule. A side-by-side examination of commercial antibodies used in prior studies suggest the original reports of APOL1 in proximal tubules likely reflects antibody non-specificity. As such, APOL1 expression in podocytes and endothelia should remain the focus for mechanistic studies in the APOL1-mediated kidney diseases.
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Bruggeman LA, Wu Z, Luo L, Madhavan S, Drawz PE, Thomas DB, Barisoni L, O'Toole JF, Sedor JR. APOL1-G0 protects podocytes in a mouse model of HIV-associated nephropathy. PLoS One 2019; 14:e0224408. [PMID: 31661509 PMCID: PMC6818796 DOI: 10.1371/journal.pone.0224408] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/11/2019] [Indexed: 11/21/2022] Open
Abstract
African polymorphisms in the gene for Apolipoprotein L1 (APOL1) confer a survival advantage against lethal trypanosomiasis but also an increased risk for several chronic kidney diseases (CKD) including HIV-associated nephropathy (HIVAN). APOL1 is expressed in renal cells, however, the pathogenic events that lead to renal cell damage and kidney disease are not fully understood. The podocyte function of APOL1-G0 versus APOL1-G2 in the setting of a known disease stressor was assessed using transgenic mouse models. Transgene expression, survival, renal pathology and function, and podocyte density were assessed in an intercross of a mouse model of HIVAN (Tg26) with two mouse models that express either APOL1-G0 or APOL1-G2 in podocytes. Mice that expressed HIV genes developed heavy proteinuria and glomerulosclerosis, and had significant losses in podocyte numbers and reductions in podocyte densities. Mice that co-expressed APOL1-G0 and HIV had preserved podocyte numbers and densities, with fewer morphologic manifestations typical of HIVAN pathology. Podocyte losses and pathology in mice co-expressing APOL1-G2 and HIV were not significantly different from mice expressing only HIV. Podocyte hypertrophy, a known compensatory event to stress, was increased in the mice co-expressing HIV and APOL1-G0, but absent in the mice co-expressing HIV and APOL1-G2. Mortality and renal function tests were not significantly different between groups. APOL1-G0 expressed in podocytes may have a protective function against podocyte loss or injury when exposed to an environmental stressor. This was absent with APOL1-G2 expression, suggesting APOL1-G2 may have lost this protective function.
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Affiliation(s)
- Leslie A. Bruggeman
- Departments of Inflammation & Immunity and Nephrology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| | - Zhenzhen Wu
- Departments of Inflammation & Immunity and Nephrology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Liping Luo
- Departments of Inflammation & Immunity and Nephrology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Sethu Madhavan
- Department of Medicine, Ohio State University, Columbus, Ohio, United States of America
| | - Paul E. Drawz
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - David B. Thomas
- Departments of Pathology, University of Miami, Miami, Florida, United States of America
| | - Laura Barisoni
- Departments of Pathology and Medicine, Duke University, Durham, North Carolina, United States of America
| | - John F. O'Toole
- Departments of Inflammation & Immunity and Nephrology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - John R. Sedor
- Departments of Inflammation & Immunity and Nephrology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
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Papeta N, Patel A, D’Agati VD, Gharavi AG. Refinement of the HIVAN1 Susceptibility Locus on Chr. 3A1-A3 via Generation of Sub-Congenic Strains. PLoS One 2016; 11:e0163860. [PMID: 27736906 PMCID: PMC5063463 DOI: 10.1371/journal.pone.0163860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/15/2016] [Indexed: 01/19/2023] Open
Abstract
HIV-1 transgenic mice on the FVB/NJ background (TgFVB) represent a validated model of HIV-associated nephropathy (HIVAN). A major susceptibility locus, HIVAN1, was previously mapped to chromosome 3A1-A3 in a cross between TgFVB and CAST/EiJ (CAST) strains, and introgression of a 51.9 Mb segment encompassing HIVAN1 from CAST into TgFVB resulted in accelerated development of nephropathy. We generated three sub-congenic strains carrying CAST alleles in the proximal or distal regions of the HIVAN1 locus (Sub-II, 3.02–38.93 Mb; Sub-III, 38.45–55.1 Mb and Sub-IV, 47.7–55.1 Mb, build 38). At 5–10 weeks of age, histologic injury and proteinuria did not differ between HIV-1 transgenic Sub-II and TgFVB mice. In contrast, HIV-1 transgenic Sub-III and Sub-IV mice displayed up to 4.4 fold more histopathologic injury and 6-fold more albuminuria compared to TgFVB mice, similar in severity to the full-length congenic mice. The Sub-IV segment defines a maximal 7.4 Mb interval for HIVAN1, and encodes 31 protein coding genes: 15 genes have missense variants differentiating CAST from FVB, and 14 genes show differential renal expression. Of these, Frem1, Foxo1, and Setd7 have been implicated in the pathogenesis of nephropathy. HIVAN1 congenic kidneys are histologically normal without the HIV-1 transgene, yet their global transcriptome is enriched for molecular signatures of apoptosis, adenoviral infection, as well as genes repressed by histone H3 lysine 27 trimethylation, a histone modification associated with HIV-1 life cycle. These data refine HIVAN1to 7.4 Mb and identify latent molecular derangements that may predispose to nephropathy upon exposure to HIV-1.
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Affiliation(s)
- Natalia Papeta
- Department of Medicine, Columbia University, New York, New York, United States of America
| | - Ami Patel
- Department of Medicine, Columbia University, New York, New York, United States of America
| | - Vivette D. D’Agati
- Department of Pathology, Columbia University, New York, New York, United States of America
| | - Ali G. Gharavi
- Department of Medicine, Columbia University, New York, New York, United States of America
- * E-mail:
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Berry RL, Ozdemir DD, Aronow B, Lindström NO, Dudnakova T, Thornburn A, Perry P, Baldock R, Armit C, Joshi A, Jeanpierre C, Shan J, Vainio S, Baily J, Brownstein D, Davies J, Hastie ND, Hohenstein P. Deducing the stage of origin of Wilms' tumours from a developmental series of Wt1-mutant mice. Dis Model Mech 2015; 8:903-17. [PMID: 26035382 PMCID: PMC4527280 DOI: 10.1242/dmm.018523] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 05/07/2015] [Indexed: 12/28/2022] Open
Abstract
Wilms' tumours, paediatric kidney cancers, are the archetypal example of tumours caused through the disruption of normal development. The genetically best-defined subgroup of Wilms' tumours is the group caused by biallelic loss of the WT1 tumour suppressor gene. Here, we describe a developmental series of mouse models with conditional loss of Wt1 in different stages of nephron development before and after the mesenchymal-to-epithelial transition (MET). We demonstrate that Wt1 is essential for normal development at all kidney developmental stages under study. Comparison of genome-wide expression data from the mutant mouse models with human tumour material of mutant or wild-type WT1 datasets identified the stage of origin of human WT1-mutant tumours, and emphasizes fundamental differences between the two human tumour groups due to different developmental stages of origin. Summary: The comparison of different nephron-specific Wt1-knockout mouse models identifies the stage of origin of human WT1-mutant Wilms' tumours.
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Affiliation(s)
- Rachel L Berry
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Derya D Ozdemir
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK
| | - Bruce Aronow
- Department of Biomedical Informatics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Nils O Lindström
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK
| | - Tatiana Dudnakova
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Anna Thornburn
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Paul Perry
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Richard Baldock
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Chris Armit
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Anagha Joshi
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK
| | - Cécile Jeanpierre
- INSERM, UMR 1163, Laboratory of Inherited Kidney Diseases, Paris 75015, France Paris Descartes - Sorbonne Paris Cité University, Imagine Institute, Paris 75015, France
| | - Jingdong Shan
- Biocenter Oulu, InfoTech Oulu, Faculty of Biochemistry and Molecular Medicine, Aapistie 5A, University of Oulu, PO Box 5000, Oulu 90014, Finland
| | - Seppo Vainio
- Biocenter Oulu, InfoTech Oulu, Faculty of Biochemistry and Molecular Medicine, Aapistie 5A, University of Oulu, PO Box 5000, Oulu 90014, Finland
| | - James Baily
- Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - David Brownstein
- Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Jamie Davies
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH8 9XD, UK
| | - Nicholas D Hastie
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Peter Hohenstein
- MRC Human Genetics Unit, MRC Institute for Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK
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Advances in the pathogenesis of HIV-associated kidney diseases. Kidney Int 2014; 86:266-74. [PMID: 24827777 DOI: 10.1038/ki.2014.167] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/03/2014] [Accepted: 02/06/2014] [Indexed: 12/17/2022]
Abstract
Despite improved outcomes among persons living with HIV who are treated with antiretroviral therapy, they remain at increased risk for acute and chronic kidney diseases. Moreover, since HIV can infect renal epithelial cells, the kidney might serve as a viral reservoir that would need to be eradicated when attempting to achieve full virologic cure. In recent years, much progress has been made in elucidating the mechanism by which HIV infects renal epithelial cells and the viral and host factors that promote development of kidney disease. Polymorphisms in APOL1 confer markedly increased risk of HIV-associated nephropathy; however, the mechanism by which ApoL1 variants may promote kidney disease remains unclear. HIV-positive persons are at increased risk of acute kidney injury, which may be a result of a high burden of subclinical kidney disease and/or viral factors and frequent exposure to nephrotoxins. Despite the beneficial effect of antiretroviral therapy in preventing and treating HIVAN, and possibly other forms of kidney disease in persons living with HIV, some of these medications, including tenofovir, indinavir, and atazanavir can induce acute and/or chronic kidney injury via mitochondrial toxicity or intratubular crystallization. Further research is needed to better understand factors that contribute to acute and chronic kidney injury in HIV-positive patients and to develop more effective strategies to prevent and treat kidney disease in this vulnerable population.
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Laouari D, Burtin M, Phelep A, Bienaime F, Noel LH, Lee DC, Legendre C, Friedlander G, Pontoglio M, Terzi F. A transcriptional network underlies susceptibility to kidney disease progression. EMBO Mol Med 2012; 4:825-39. [PMID: 22711280 PMCID: PMC3494079 DOI: 10.1002/emmm.201101127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 05/02/2012] [Accepted: 05/07/2012] [Indexed: 01/28/2023] Open
Abstract
The molecular networks that control the progression of chronic kidney diseases (CKD) are poorly defined. We have recently shown that the susceptibility to development of renal lesions after nephron reduction is controlled by a locus on mouse chromosome 6 and requires epidermal growth factor receptor (EGFR) activation. Here, we identified microphthalmia-associated transcription factor A (MITF-A), a bHLH-Zip transcription factor, as a modifier of CKD progression. Sequence analysis revealed a strain-specific mutation in the 5' UTR that decreases MITF-A protein synthesis in lesion-prone friend virus B NIH (FVB/N) mice. More importantly, we dissected the molecular pathway by which MITF-A modulates CKD progression. MITF-A interacts with histone deacetylases to repress the transcription of TGF-α, a ligand of EGFR, and antagonizes transactivation by its related partner, transcription factor E3 (TFE3). Consistent with the key role of this network in CKD, Tgfa gene inactivation protected FVB/N mice from renal deterioration after nephron reduction. These data are relevant to human CKD, as we found that the TFE3/MITF-A ratio was increased in patients with damaged kidneys. Our study uncovers a novel transcriptional network and unveils novel potential prognostic and therapeutic targets for preventing human CKD progression.
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Affiliation(s)
- Denise Laouari
- INSERM U845, Centre de Recherche "Croissance et Signalisation", Université Paris Descartes, Sorbonne Paris Cité, Hôpital Necker Enfants Malades, Paris, France
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Bostrom MA, Kao WHL, Li M, Abboud HE, Adler SG, Iyengar SK, Kimmel PL, Hanson RL, Nicholas SB, Rasooly RS, Sedor JR, Coresh J, Kohn OF, Leehey DJ, Thornley-Brown D, Bottinger EP, Lipkowitz MS, Meoni LA, Klag MJ, Lu L, Hicks PJ, Langefeld CD, Parekh RS, Bowden DW, Freedman BI. Genetic association and gene-gene interaction analyses in African American dialysis patients with nondiabetic nephropathy. Am J Kidney Dis 2011; 59:210-21. [PMID: 22119407 DOI: 10.1053/j.ajkd.2011.09.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 09/16/2011] [Indexed: 11/11/2022]
Abstract
BACKGROUND African Americans have increased susceptibility to nondiabetic nephropathy relative to European Americans. STUDY DESIGN Follow-up of a pooled genome-wide association study (GWAS) in African American dialysis patients with nondiabetic nephropathy; novel gene-gene interaction analyses. SETTING & PARTICIPANTS Wake Forest sample: 962 African American nondiabetic nephropathy cases, 931 non-nephropathy controls. Replication sample: 668 Family Investigation of Nephropathy and Diabetes (FIND) African American nondiabetic nephropathy cases, 804 non-nephropathy controls. PREDICTORS Individual genotyping of top 1,420 pooled GWAS-associated single-nucleotide polymorphisms (SNPs) and 54 SNPs in 6 nephropathy susceptibility genes. OUTCOMES APOL1 genetic association and additional candidate susceptibility loci interacting with or independently from APOL1. RESULTS The strongest GWAS associations included 2 noncoding APOL1 SNPs, rs2239785 (OR, 0.33; dominant; P = 5.9 × 10(-24)) and rs136148 (OR, 0.54; additive; P = 1.1 × 10(-7)) with replication in FIND (P = 5.0 × 10(-21) and 1.9 × 10(-05), respectively). rs2239785 remained associated significantly after controlling for the APOL1 G1 and G2 coding variants. Additional top hits included a CFH SNP (OR from meta-analysis in the 3,367 African American cases and controls, 0.81; additive; P = 6.8 × 10(-4)). The 1,420 SNPs were tested for interaction with APOL1 G1 and G2 variants. Several interactive SNPs were detected; the most significant was rs16854341 in the podocin gene (NPHS2; P = 0.0001). LIMITATIONS Nonpooled GWASs have not been performed in African American patients with nondiabetic nephropathy. CONCLUSIONS This follow-up of a pooled GWAS provides additional and independent evidence that APOL1 variants contribute to nondiabetic nephropathy in African Americans and identified additional associated and interactive nondiabetic nephropathy susceptibility genes.
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