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Itoku A, Isaac J, Wilson S, Reidy K, Kaskel F. APOL1 Nephropathy Risk Variants Through the Life Course: A Review. Am J Kidney Dis 2024; 84:102-110. [PMID: 38341125 DOI: 10.1053/j.ajkd.2023.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/26/2023] [Accepted: 12/05/2023] [Indexed: 02/12/2024]
Abstract
Two variant alleles of the gene apolipoprotein L1 (APOL1), known as risk variants (RVs), are a major contributor to kidney disease burden in those of African descent. The APOL1 protein contributes to innate immunity and may protect against Trypanosoma, HIV, Salmonella, and leishmaniasis. However, the effects of carrying 1 or more RVs contribute to a variety of disease processes starting as early as in utero and can be exacerbated by other factors (or "second hits"). Indeed, these genetic variations interact with environmental exposures, infections, and systemic disease to modify health outcomes across the life span. This review focuses on APOL1-associated diseases through the life-course perspective and discusses how early exposure to second hits can impact long-term outcomes. APOL1-related kidney disease typically presents in adolescents to young adults, and individuals harboring RVs are more likely to progress to kidney failure than are those with kidney disease who lack APOL-1 RVs. Ongoing research is aimed at elucidating the association of APOL1 RV effects with adverse donor and recipient kidney transplant outcomes. Unfortunately, there is currently no established treatment for APOL1-associated nephropathy. Long-term research is needed to evaluate the risk and protective factors associated with APOL1 RVs at different stages of life.
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Affiliation(s)
- Ai Itoku
- Division of Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, New York
| | - Jaya Isaac
- Division of Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, New York
| | - Scott Wilson
- Albert Einstein College of Medicine, Bronx, New York.
| | - Kimberly Reidy
- Division of Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, New York
| | - Frederick Kaskel
- Division of Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, New York
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Pell J, Nagata S, Menon MC. Nonpodocyte Roles of APOL1 Variants: An Evolving Paradigm. KIDNEY360 2023; 4:e1325-e1331. [PMID: 37461136 PMCID: PMC10550003 DOI: 10.34067/kid.0000000000000216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023]
Abstract
Since the seminal discovery of the trypanolytic, exonic variants in apolipoprotein L1 (APOL1) and their association with kidney disease in individuals of recent African ancestry, a wide body of research has emerged offering key insights into the mechanisms of disease. Importantly, the podocyte has become a focal point for our understanding of how risk genotype leads to disease, with activation of putative signaling pathways within the podocyte identified as playing a causal role in podocytopathy, FSGS, and progressive renal failure. However, the complete mechanism of genotype-to-phenotype progression remains incompletely understood in APOL1-risk individuals. An emerging body of evidence reports more than podocyte-intrinsic expression of APOL1 risk variants is needed for disease to manifest. This article reviews the seminal data and reports which placed the podocyte at the center of our understanding of APOL1-FSGS, as well as the evident shortcomings of this podocentric paradigm. We examine existing evidence for environmental and genetic factors that may influence disease, drawing from both clinical data and APOL1's fundamental role as an immune response gene. We also review the current body of data for APOL1's impact on nonpodocyte cells, including endothelial cells, the placenta, and immune cells in both a transplant and native setting. Finally, we discuss the implications of these emerging data and how the paradigm of disease might evolve as a result.
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Affiliation(s)
- John Pell
- Department of Medicine , Yale University, New Haven , Connecticut
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3
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Chung CP, Karakoc G, Dickson A, Liu G, Gamboa JL, Mosley JD, Cox NJ, Kawai VK. APOL1 and the risk of adverse renal outcomes in patients of African ancestry with systemic lupus erythematosus. Lupus 2023; 32:763-770. [PMID: 37105192 DOI: 10.1177/09612033231172660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
BACKGROUND Systemic lupus erythematosus (SLE) disproportionately affects individuals of African ancestry (AA) compared to European ancestry (EA). In the general population, high risk (HR) variants in the apolipoprotein L1 (APOL1) gene increase the risk of renal and hypertensive disorders in individuals of AA. Since SLE is characterized by an interferon signature and APOL1 expression is driven by interferon, we examined the hypothesis that APOL1 HR genotypes predominantly drive higher rates of renal and hypertensive-related comorbidities observed in SLE patients of AA versus those of EA. METHODS We performed a retrospective cohort study in patients with SLE of EA and AA using a genetic biobank linked to de-identified electronic health records. APOL1 HR genotypes were defined as G1/G1, G2/G2, or G1/G2 and low risk (LR) genotypes as 1 or 0 copies of the G1 and G2 alleles. To identify renal and hypertensive-related disorders that differed in prevalence by ancestry, we used a phenome-wide association approach. We then used logistic regression to compare the prevalence of renal and hypertensive-related disorders in EA and AA patients, both including and excluding patients with the APOL1 HR genotype. In a sensitivity analysis, we examined the association of end stage renal disease secondary to lupus nephritis (LN-related ESRD) with ancestry and the APOL1 genotype. RESULTS We studied 784 patients with SLE; 195 (24.9%) were of AA, of whom 27 (13.8%) had APOL1 HR genotypes. Eighteen renal and hypertensive-related phenotypes were more common in AA than EA patients (p-value ≤ 1.4E-4). All phenotypes remained significantly different after exclusion of patients with APOL1 HR genotypes, and most point odds ratios (ORs) decreased only slightly. Even among ORs with the greatest decrease, risk for AA patients without the APOL1 HR genotype remained significantly elevated compared to EA patients. In the sensitivity analysis, LN-related ESRD was more prevalent in SLE patients of AA versus EA and AA patients with the APOL1 HR genotype versus LR (p-value < .05 for both). CONCLUSION The higher prevalence of renal and hypertensive disorders in SLE patients of AA compared to those of EA is not fully explained by the presence of APOL1 high risk variants.
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Affiliation(s)
- Cecilia P Chung
- Division of Rheumatology and Immunology, Department of Medicine Vanderbilt University Medical Center, Nashville, TN, USA
- Tennessee Valley Healthcare System - Nashville Campus, Nashville, TN, USA
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Rheumatology, University of Miami, Miami, FL, USA
- Miami VA Healthcare System, Miami, FL, USA
| | - Gul Karakoc
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alyson Dickson
- Division of Rheumatology and Immunology, Department of Medicine Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ge Liu
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jorge L Gamboa
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan D Mosley
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nancy J Cox
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Vivian K Kawai
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
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Blazer A, Qian Y, Schlegel MP, Algasas H, Buyon JP, Cadwell K, Cammer M, Heffron SP, Liang FX, Mehta-Lee S, Niewold T, Rasmussen SE, Clancy RM. APOL1 variant-expressing endothelial cells exhibit autophagic dysfunction and mitochondrial stress. Front Genet 2022; 13:769936. [PMID: 36238153 PMCID: PMC9551299 DOI: 10.3389/fgene.2022.769936] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 08/16/2022] [Indexed: 12/09/2022] Open
Abstract
Polymorphisms in the Apolipoprotein L1 (APOL1) gene are common in ancestrally African populations, and associate with kidney injury and cardiovascular disease. These risk variants (RV) provide an advantage in resisting Trypanosoma brucei, the causal agent of African trypanosomiasis, and are largely absent from non-African genomes. Clinical associations between the APOL1 high risk genotype (HRG) and disease are stronger in those with comorbid infectious or immune disease. To understand the interaction between cytokine exposure and APOL1 cytotoxicity, we established human umbilical vein endothelial cell (HUVEC) cultures representing each APOL1 genotype. Untreated HUVECs were compared to IFNɣ-exposed; and APOL1 expression, mitochondrial function, lysosome integrity, and autophagic flux were measured. IFNɣ increased median APOL1 expression across all genotypes 22.1 (8.3 to 29.8) fold (p=0.02). Compared to zero risk variant-carrying HUVECs (0RV), HUVECs carrying 2 risk variant copies (2RV) showed both depressed baseline and maximum mitochondrial oxygen consumption (p<0.01), and impaired mitochondrial networking on MitoTracker assays. These cells also demonstrated a contracted lysosomal compartment, and an accumulation of autophagosomes suggesting a defect in autophagic flux. Upon blocking autophagy with non-selective lysosome inhibitor, hydroxychloroquine, autophagosome accumulation between 0RV HUVECs and untreated 2RV HUVECs was similar, implicating lysosomal dysfunction in the HRG-associated autophagy defect. Compared to 0RV and 2RV HUVECs, HUVECs carrying 1 risk variant copy (1RV) demonstrated intermediate mitochondrial respiration and autophagic flux phenotypes, which were exacerbated with IFNɣ exposure. Taken together, our data reveal that IFNɣ induces APOL1 expression, and that each additional RV associates with mitochondrial dysfunction and autophagy inhibition. IFNɣ amplifies this phenotype even in 1RV HUVECs, representing the first description of APOL1 pathobiology in variant heterozygous cell cultures.
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Affiliation(s)
- Ashira Blazer
- Division of Rheumatology, Department of Medicine, Hospital for Special Surgery, New York, NY, United States
| | - Yingzhi Qian
- Division of Biostatistics, Department of Population Health, New York University School of Medicine, New York, NY, United States
| | - Martin Paul Schlegel
- Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY, United States
| | - Huda Algasas
- Division of Rheumatology, Department of Medicine, Hospital for Special Surgery, New York, NY, United States
| | - Jill P. Buyon
- Division of Rheumatology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, United States
| | - Ken Cadwell
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Michael Cammer
- DART Microscopy Laboratory, New York University Grossman School of Medicine, New York University School of Medicine, New York, NY, United States
| | - Sean P. Heffron
- Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY, United States
| | - Feng-Xia Liang
- DART Microscopy Laboratory, New York University Grossman School of Medicine, New York University School of Medicine, New York, NY, United States
| | - Shilpi Mehta-Lee
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, United States
| | - Timothy Niewold
- Division of Rheumatology, Department of Medicine, Hospital for Special Surgery, New York, NY, United States
| | - Sara E. Rasmussen
- Division of Rheumatology, Department of Medicine, Hospital for Special Surgery, New York, NY, United States
| | - Robert M. Clancy
- Division of Rheumatology, Department of Medicine, New York University Grossman School of Medicine, New York, NY, United States
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Ilori T, Watanabe A, Ng KH, Solarin A, Sinha A, Gbadegesin R. Genetics of Chronic Kidney Disease in Low-Resource Settings. Semin Nephrol 2022; 42:151314. [PMID: 36801667 PMCID: PMC10272019 DOI: 10.1016/j.semnephrol.2023.151314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Advances in kidney genomics in the past 20 years has opened the door for more precise diagnosis of kidney disease and identification of new and specific therapeutic agents. Despite these advances, an imbalance exists between low-resource and affluent regions of the world. Individuals of European ancestry from the United States, United Kingdom, and Iceland account for 16% of the world's population, but represent more than 80% of all genome-wide association studies. South Asia, Southeast Asia, Latin America, and Africa together account for 57% of the world population but less than 5% of genome-wide association studies. Implications of this difference include limitations in new variant discovery, inaccurate interpretation of the effect of genetic variants in non-European populations, and unequal access to genomic testing and novel therapies in resource-poor regions. It also further introduces ethical, legal, and social pitfalls, and ultimately may propagate global health inequities. Ongoing efforts to reduce the imbalance in low-resource regions include funding and capacity building, population-based genome sequencing, population-based genome registries, and genetic research networks. More funding, training, and capacity building for infrastructure and expertise is needed in resource-poor regions. Focusing on this will ensure multiple-fold returns on investments in genomic research and technology.
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Affiliation(s)
- Titilayo Ilori
- Division of Nephrology, Boston University School of Medicine, Boston, MA
| | - Andreia Watanabe
- Division of Molecular Medicine, Department of Pediatrics, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Kar-Hui Ng
- Department of Pediatrics, Yong Loo Lin School of Medicine, Singapore
| | - Adaobi Solarin
- Department of Pediatrics and Child Health, Lagos State University College of Medicine, Ikeja, Lagos, Nigeria
| | - Aditi Sinha
- Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Rasheed Gbadegesin
- Division of Nephrology, Department of Pediatrics, Duke University School of Medicine, Durham, NC.
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Arora S, Rovin BH. Expert Perspective: An Approach to Refractory Lupus Nephritis. Arthritis Rheumatol 2022; 74:915-926. [PMID: 35166048 DOI: 10.1002/art.42092] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/24/2022] [Accepted: 02/09/2022] [Indexed: 11/06/2022]
Affiliation(s)
| | - Brad H Rovin
- The Ohio State University Wexner Medical Center, Columbus, OH
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Muehlig AK, Gies S, Huber TB, Braun F. Collapsing Focal Segmental Glomerulosclerosis in Viral Infections. Front Immunol 2022; 12:800074. [PMID: 35095882 PMCID: PMC8792967 DOI: 10.3389/fimmu.2021.800074] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/20/2021] [Indexed: 01/10/2023] Open
Abstract
Collapsing glomerulopathy represents a special variant of the proteinuric kidney disease focal segmental glomerulosclerosis (FSGS). Histologically, the collapsing form of FSGS (cFSGS) is characterized by segmental or global condensation and obliteration of glomerular capillaries, the appearance of hyperplastic and hypertrophic podocytes and severe tubulointerstitial damage. Clinically, cFSGS patients present with acute kidney injury, nephrotic-range proteinuria and are at a high risk of rapid progression to irreversible kidney failure. cFSGS can be attributed to numerous etiologies, namely, viral infections like HIV, cytomegalovirus, Epstein-Barr-Virus, and parvovirus B19 and also drugs and severe ischemia. Risk variants of the APOL1 gene, predominantly found in people of African descent, increase the risk of developing cFSGS. Patients infected with the new Corona-Virus SARS-CoV-2 display an increased rate of acute kidney injury (AKI) in severe cases of COVID-19. Besides hemodynamic instability, cytokine mediated injury and direct viral entry and infection of renal epithelial cells contributing to AKI, there are emerging reports of cFSGS associated with SARS-CoV-2 infection in patients of mainly African ethnicity. The pathogenesis of cFSGS is proposed to be linked with direct viral infection of podocytes, as described for HIV-associated glomerulopathy. Nevertheless, there is growing evidence that the systemic inflammatory cascade, activated in acute viral infections like COVID-19, is a major contributor to the impairment of basic cellular functions in podocytes. This mini review will summarize the current knowledge on cFSGS associated with viral infections with a special focus on the influence of systemic immune responses and potential mechanisms propagating the development of cFSGS.
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Affiliation(s)
- Anne K Muehlig
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sydney Gies
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabian Braun
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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The Pathogenesis, Molecular Mechanisms, and Therapeutic Potential of the Interferon Pathway in Systemic Lupus Erythematosus and Other Autoimmune Diseases. Int J Mol Sci 2021; 22:ijms222011286. [PMID: 34681945 PMCID: PMC8540355 DOI: 10.3390/ijms222011286] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 12/11/2022] Open
Abstract
Therapeutic success in treating patients with systemic lupus erythematosus (SLE) is limited by the multivariate disease etiology, multi-organ presentation, systemic involvement, and complex immunopathogenesis. Agents targeting B-cell differentiation and survival are not efficacious for all patients, indicating a need to target other inflammatory mediators. One such target is the type I interferon pathway. Type I interferons upregulate interferon gene signatures and mediate critical antiviral responses. Dysregulated type I interferon signaling is detectable in many patients with SLE and other autoimmune diseases, and the extent of this dysregulation is associated with disease severity, making type I interferons therapeutically tangible targets. The recent approval of the type I interferon-blocking antibody, anifrolumab, by the US Food and Drug Administration for the treatment of patients with SLE demonstrates the value of targeting this pathway. Nevertheless, the interferon pathway has pleiotropic biology, with multiple cellular targets and signaling components that are incompletely understood. Deconvoluting the complexity of the type I interferon pathway and its intersection with lupus disease pathology will be valuable for further development of targeted SLE therapeutics. This review summarizes the immune mediators of the interferon pathway, its association with disease pathogenesis, and therapeutic modalities targeting the dysregulated interferon pathway.
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Zhang Z, Sun Z, Fu J, Lin Q, Banu K, Chauhan K, Planoutene M, Wei C, Salem F, Yi Z, Liu R, Cravedi P, Cheng H, Hao K, O'Connell PJ, Ishibe S, Zhang W, Coca SG, Gibson IW, Colvin RB, He JC, Heeger PS, Murphy BT, Menon MC. Recipient APOL1 risk alleles associate with death-censored renal allograft survival and rejection episodes. J Clin Invest 2021; 131:e146643. [PMID: 34499625 DOI: 10.1172/jci146643] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 09/01/2021] [Indexed: 11/17/2022] Open
Abstract
Apolipoprotein L1 (APOL1) risk-alleles in donor kidneys associate with graft loss but whether recipient risk-allele expression impacts transplant outcomes is unclear. To test whether recipient APOL1 risk-alleles independently correlate with transplant outcomes, we analyzed genome-wide SNP genotyping data of donors and recipients from two kidney transplant cohorts, Genomics of Chronic Allograft Rejection (GOCAR) and Clinical Trials in Organ Transplantation (CTOT1/17). We estimated genetic ancestry (quantified as proportion of African ancestry or pAFR) by ADMIXTURE and correlated APOL1 genotypes and pAFR with outcomes. In the GOCAR discovery set, we observed that the number of recipient APOL1 G1/G2 alleles (R-nAPOL1) associated with increased risk of death-censored allograft loss (DCAL), independent of ancestry (HR = 2.14; P = 0.006), and within the subgroup of African American and Hispanic (AA/H) recipients (HR = 2.36; P = 0.003). R-nAPOL1 also associated with increased risk of any T cell-mediated rejection (TCMR) event. These associations were validated in CTOT1/17. Ex vivo studies of peripheral blood mononuclear cells revealed unanticipated high APOL1 expression in activated CD4+/CD8+ T cells and natural killer cells. We detected enriched immune response gene pathways in risk-allele carriers vs. non-carriers on the kidney transplant waitlist and among healthy controls. Our findings demonstrate an immunomodulatory role for recipient APOL1 risk-alleles associating with TCMR and DCAL. This finding has broader implications for immune mediated injury to native kidneys.
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Affiliation(s)
- Zhongyang Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Zeguo Sun
- Division of Nephrology, Department of Medicine, Icahn school of Medicine at Mount Sinai, New York, United States of America
| | - Jia Fu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Qisheng Lin
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Khadija Banu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Kinsuk Chauhan
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Marina Planoutene
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Chengguo Wei
- Division of Nephrology, Department of Medicine, Icahn school of Medicine at Mount Sinai, New York, United States of America
| | - Fadi Salem
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Zhengzi Yi
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Ruijie Liu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Paolo Cravedi
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Haoxiang Cheng
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Ke Hao
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Philip J O'Connell
- Centre for Transplant and Renal Research, Westmead Millennium Institute for Medical Research, Sydney University, Westmead, Australia
| | - Shuta Ishibe
- Department of Medicine, Yale University School of Medicine, New Haven, United States of America
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn school of Medicine at Mount Sinai, New York, United States of America
| | - Steven G Coca
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Ian W Gibson
- Department of Pathology, University of Manitoba, Winnipeg, Canada
| | - Robert B Colvin
- Department of Pathology, Massachusetts General Hospital, Boston, United States of America
| | - John C He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Peter S Heeger
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Barbara T Murphy
- Division of Nephrology, Department of Medicine, Icahn school of Medicine at Mount Sinai, New York, United States of America
| | - Madhav C Menon
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, United States of America
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Watanabe A, Guaragna MS, Belangero VMS, Casimiro FMS, Pesquero JB, de Santis Feltran L, Palma LMP, Varela P, de Menezes Neves PDM, Lerario AM, de Souza ML, de Mello MP, de Brito Lutaif ACG, Ferrari CR, Sampson MG, Onuchic LF, Nogueira PCK. APOL1 in an ethnically diverse pediatric population with nephrotic syndrome: implications in focal segmental glomerulosclerosis and other diagnoses. Pediatr Nephrol 2021; 36:2327-2336. [PMID: 33585978 DOI: 10.1007/s00467-021-04960-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/25/2020] [Accepted: 01/20/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND APOL1 high-risk genotypes (HRG) are associated with increased risk of kidney disease in individuals of African ancestry. We analyzed the effects of APOL1 risk variants on an ethnically diverse Brazilian pediatric nephrotic syndrome (NS) cohort. METHODS Multicenter study including 318 NS patients, categorized as progressors to advanced CKD [estimated glomerular filtration rate (eGFR)] < 30 mL/min/1.73 m2] and slow/non-progressors (eGFR > 30 mL/min/1.73 m2 through the study). We employed Cox regression with progression time as the outcome and APOL1 genotype as the independent variable. We tested this association in the entire cohort and three subgroups; (1) focal segmental glomerulosclerosis (FSGS), (2) steroid-resistant NS (SRNS), and (3) those who underwent kidney biopsy. RESULTS Nineteen patients (6%) had an HRG. Of these, 47% were self-reported White. Patients with HRG manifested NS at older ages and presented higher frequencies of FSGS and SRNS. HRG patients progressed to advanced CKD more often than low-risk-genotype (LRG) children in the whole NS cohort (p = 0.001) and the three subgroups. In SRNS and biopsied patients, a single risk variant was associated with trends of higher CKD progression risk. CONCLUSIONS Novel discoveries include a substantial prevalence of HRG among patients self-reported White, worse kidney outcomes in HRG versus LRG children in the FSGS subgroup, and a trend of higher CKD progression risk associated with a single risk variant in the SRNS cohort. These findings suggest APOL1-associated NS extends beyond patients self-reported non-White, the HRG effect is independent of FSGS, and a single risk variant may have a detrimental impact in children with NS.
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Affiliation(s)
- Andreia Watanabe
- Department of Pediatrics, University of São Paulo School of Medicine, São Paulo, Brazil
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Mara Sanches Guaragna
- Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, Brazil
| | | | - Fernanda Maria Serafim Casimiro
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | - João Bosco Pesquero
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | | | | | - Patrícia Varela
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | - Precil Diego Miranda de Menezes Neves
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil
- Division of Nephrology, University of São Paulo School of Medicine, São Paulo, Brazil
| | | | - Marcela Lopes de Souza
- Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, Brazil
| | | | | | | | - Matthew Gordon Sampson
- Division of Pediatric Nephrology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Broad Institute, Cambridge, MA, USA
| | - Luiz Fernando Onuchic
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil.
- Division of Nephrology, University of São Paulo School of Medicine, São Paulo, Brazil.
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Blazer A, Dey ID, Nwaukoni J, Reynolds M, Ankrah F, Algasas H, Ahmed T, Divers J. Apolipoprotein L1 risk genotypes in Ghanaian patients with systemic lupus erythematosus: a prospective cohort study. Lupus Sci Med 2021; 8:8/1/e000460. [PMID: 33461980 PMCID: PMC7816898 DOI: 10.1136/lupus-2020-000460] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/13/2020] [Accepted: 12/23/2020] [Indexed: 01/13/2023]
Abstract
Objective Two apolipoprotein L1 (APOL1) risk variants (RV) are enriched in sub-Saharan African populations due to conferred resistance to Trypanosoma brucei. These variants associate with adverse renal outcomes by multiple causes including SLE. Despite emerging reports that SLE is common in Ghana, where APOL1 variant allelic frequencies are high, the regional contribution to SLE outcomes has not been described. Accordingly, this prospective longitudinal cohort study tested the associations between APOL1 high-risk genotypes and kidney outcomes, organ damage accrual and death in 100 Ghanaian patients with SLE. Methods This was a prospective cohort study of 100 SLE outpatients who sought care at Korle bu Teaching Hospital in Accra, Ghana. Adult patients who met 4 American College of Rheumatology criteria for SLE were genotyped for APOL1 and followed longitudinally for SLE activity as measured by the Safety of Estrogens in Lupus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) hybrid and organ injury as measured by the Systemic Lupus International Collaborating Clinics Damage Index (SDI) at baseline and every 6 months for 1 year. Outcomes of interest were kidney function, SDI and case fatality. Results Assuming a recessive inheritance, the APOL1 high-risk genotype (2RV) associated with end-stage renal disease (ESRD) at an OR of 14 (p=0.008). These patients accrued more SDI points particularly in renal and neurological domains. The SDI was 81.3% higher in 2RV patients compared with 0RV or 1RV patients despite no difference in SLE activity (p=0.01). After a 12-month period of observation, 3/12 (25%) of the 2RV patients died compared with 2/88 (2.3%) of the 0RV or 1RV carriers (OR=13.6, p=0.01). Deaths were due to end-stage kidney disease and heart failure. Conclusion APOL1 RVs were heritable risk factors for morbidity and mortality in this Ghanaian SLE cohort. Despite no appreciable differences in SLE activity, APOL1 high-risk patients exhibited progressive renal disease, organ damage accrual and a 13-fold higher case fatality.
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Affiliation(s)
- Ashira Blazer
- Department of Medicine, Division of Rheumatology, NYU Langone Health, New York, New York, USA
| | - Ida Dzifa Dey
- Department of Medicine, Division of Rheumatology, University of Ghana, Legon, Greater Accra, Ghana
| | - Janet Nwaukoni
- Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, USA
| | | | - Festus Ankrah
- Internal Medicine, University of Ghana, Legon, Greater Accra, Ghana
| | | | - Tasneem Ahmed
- Department of Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Jasmin Divers
- Department of Biostatistics, Division of Health Sciences Research, NYU Winthrop Hospital, Mineola, New York, USA
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Affiliation(s)
- Linda T Hiraki
- Pediatrics and Epidemiology, Dalla Lana School of Public Health, University of Toronto, and Clinician Scientist, Division of Rheumatology, and Scientist, Child Health Evaluative Sciences and Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Datta S, Kataria R, Zhang JY, Moore S, Petitpas K, Mohamed A, Zahler N, Pollak MR, Olabisi OA. Kidney Disease-Associated APOL1 Variants Have Dose-Dependent, Dominant Toxic Gain-of-Function. J Am Soc Nephrol 2020; 31:2083-2096. [PMID: 32675303 PMCID: PMC7461666 DOI: 10.1681/asn.2020010079] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/12/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Two coding renal risk variants (RRVs) of the APOL1 gene (G1 and G2) are associated with large increases in CKD rates among populations of recent African descent, but the underlying molecular mechanisms are unknown. Mammalian cell culture models are widely used to study cytotoxicity of RRVs, but results have been contradictory. It remains unclear whether cytotoxicity is RRV-dependent or driven solely by variant-independent overexpression. It is also unknown whether expression of the reference APOL1 allele, the wild-type G0, could prevent cytotoxicity of RRVs. METHODS We generated tetracycline-inducible APOL1 expression in human embryonic kidney HEK293 cells and examined the effects of increased expression of APOL1 (G0, G1, G2, G0G0, G0G1, or G0G2) on known cytotoxicity phenotypes, including reduced viability, increased swelling, potassium loss, aberrant protein phosphorylation, and dysregulated energy metabolism. Furthermore, whole-genome transcriptome analysis examined deregulated canonical pathways. RESULTS At moderate expression, RRVs but not G0 caused cytotoxicity in a dose-dependent manner that coexpression of G0 did not reduce. RRVs also have dominant effects on canonical pathways relevant for the cellular stress response. CONCLUSIONS In HEK293 cells, RRVs exhibit a dominant toxic gain-of-function phenotype that worsens with increasing expression. These observations suggest that high steady-state levels of RRVs may underlie cellular injury in APOL1 nephropathy, and that interventions that reduce RRV expression in kidney compartments may mitigate APOL1 nephropathy.
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Affiliation(s)
- Somenath Datta
- Division of Nephrology and Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Rama Kataria
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Jia-Yue Zhang
- Harvard Medical School, Boston, Massachusetts
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Savannah Moore
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Kaitlyn Petitpas
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Adam Mohamed
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | | | - Martin R Pollak
- Harvard Medical School, Boston, Massachusetts
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Opeyemi A Olabisi
- Division of Nephrology and Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
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