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Meyer BJ, Kunz N, Seki S, Higgins R, Ghosh A, Hupfer R, Baldrich A, Hirsiger JR, Jauch AJ, Burgener AV, Lötscher J, Aschwanden M, Dickenmann M, Stegert M, Berger CT, Daikeler T, Heijnen I, Navarini AA, Rudin C, Yamamoto H, Kemper C, Hess C, Recher M. Immunologic and Genetic Contributors to CD46-Dependent Immune Dysregulation. J Clin Immunol 2023; 43:1840-1856. [PMID: 37477760 PMCID: PMC10661731 DOI: 10.1007/s10875-023-01547-y] [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] [Received: 10/27/2022] [Accepted: 06/30/2023] [Indexed: 07/22/2023]
Abstract
Mutations in CD46 predispose to atypical hemolytic uremic syndrome (aHUS) with low penetrance. Factors driving immune-dysregulatory disease in individual mutation carriers have remained ill-understood. In addition to its role as a negative regulator of the complement system, CD46 modifies T cell-intrinsic metabolic adaptation and cytokine production. Comparative immunologic analysis of diseased vs. healthy CD46 mutation carriers has not been performed in detail yet. In this study, we comprehensively analyzed clinical, molecular, immune-phenotypic, cytokine secretion, immune-metabolic, and genetic profiles in healthy vs. diseased individuals carrying a rare, heterozygous CD46 mutation identified within a large single family. Five out of six studied individuals carried a CD46 gene splice-site mutation causing an in-frame deletion of 21 base pairs. One child suffered from aHUS and his paternal uncle manifested with adult-onset systemic lupus erythematosus (SLE). Three mutation carriers had no clinical evidence of CD46-related disease to date. CD4+ T cell-intrinsic CD46 expression was uniformly 50%-reduced but was comparable in diseased vs. healthy mutation carriers. Reconstitution experiments defined the 21-base pair-deleted CD46 variant as intracellularly-but not surface-expressed and haploinsufficient. Both healthy and diseased mutation carriers displayed reduced CD46-dependent T cell mitochondrial adaptation. Diseased mutation carriers had lower peripheral regulatory T cell (Treg) frequencies and carried potentially epistatic, private rare variants in other inborn errors of immunity (IEI)-associated proinflammatory genes, not found in healthy mutation carriers. In conclusion, low Treg and rare non-CD46 immune-gene variants may contribute to clinically manifest CD46 haploinsufficiency-associated immune-dysregulation.
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Affiliation(s)
- Benedikt J Meyer
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Natalia Kunz
- Immunobiology Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Complement and Inflammation Research Section, CIRS, DIR, NHLBI, NIH, Bethesda, USA
| | - Sayuri Seki
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Adhideb Ghosh
- Dermatology, University Hospital Basel, Basel, Switzerland
- Competence Center for Personalized Medicine, University of Zürich/Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Robin Hupfer
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Adrian Baldrich
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Julia R Hirsiger
- Translational Immunology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Annaïse J Jauch
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Anne-Valérie Burgener
- Immunobiology Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Jonas Lötscher
- Immunobiology Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Markus Aschwanden
- Department of Angiology, University Hospital Basel, Basel, Switzerland
| | - Michael Dickenmann
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - Mihaela Stegert
- Rheumatology Clinic, University Hospital Basel, Basel, Switzerland
| | - Christoph T Berger
- Translational Immunology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- University Center for Immunology, University Hospital Basel, Basel, Switzerland
| | - Thomas Daikeler
- Rheumatology Clinic, University Hospital Basel, Basel, Switzerland
- University Center for Immunology, University Hospital Basel, Basel, Switzerland
| | - Ingmar Heijnen
- Division Medical Immunology, Laboratory Medicine, University Hospital Basel, Basel, Switzerland
| | | | - Christoph Rudin
- University Children's Hospital, University of Basel, Basel, Switzerland
| | - Hiroyuki Yamamoto
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Claudia Kemper
- Complement and Inflammation Research Section, CIRS, DIR, NHLBI, NIH, Bethesda, USA
| | - Christoph Hess
- Immunobiology Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Mike Recher
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland.
- University Center for Immunology, University Hospital Basel, Basel, Switzerland.
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Rydberg V, Aradottir SS, Kristoffersson AC, Svitacheva N, Karpman D. Genetic investigation of Nordic patients with complement-mediated kidney diseases. Front Immunol 2023; 14:1254759. [PMID: 37744338 PMCID: PMC10513385 DOI: 10.3389/fimmu.2023.1254759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/21/2023] [Indexed: 09/26/2023] Open
Abstract
Background Complement activation in atypical hemolytic uremic syndrome (aHUS), C3 glomerulonephropathy (C3G) and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) may be associated with rare genetic variants. Here we describe gene variants in the Swedish and Norwegian populations. Methods Patients with these diagnoses (N=141) were referred for genetic screening. Sanger or next-generation sequencing were performed to identify genetic variants in 16 genes associated with these conditions. Nonsynonymous genetic variants are described when they have a minor allele frequency of <1% or were previously reported as being disease-associated. Results In patients with aHUS (n=94, one also had IC-MPGN) 68 different genetic variants or deletions were identified in 60 patients, of which 18 were novel. Thirty-two patients had more than one genetic variant. In patients with C3G (n=40) 29 genetic variants, deletions or duplications were identified in 15 patients, of which 9 were novel. Eight patients had more than one variant. In patients with IC-MPGN (n=7) five genetic variants were identified in five patients. Factor H variants were the most frequent in aHUS and C3 variants in C3G. Seventeen variants occurred in more than one condition. Conclusion Genetic screening of patients with aHUS, C3G and IC-MPGN is of paramount importance for diagnostics and treatment. In this study, we describe genetic assessment of Nordic patients in which 26 novel variants were found.
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Affiliation(s)
| | | | | | | | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
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Familial Atypical Hemolytic Uremic Syndrome with Positive p.S1191L (c.3572C>T) Mutation on the CFH Gene: A Single-center Experience. Balkan J Med Genet 2021; 24:81-88. [PMID: 34447663 PMCID: PMC8366473 DOI: 10.2478/bjmg-2021-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The atypical hemolytic uremic syndrome (aHUS) is characterized by thrombocytopenia, microangiopathic hemolytic anemia and acute kidney injury (AKI), which can exhibit a poor prognosis. Complement factor H (CFH) gene mutations play a key role in this disease, which may be sporadic or familial. We studied 13 people from the same family, investigated for gene mutations of the familial aHUS after a family member presented to our emergency clinic with the aHUS and reported a family history of chronic renal failure. The p.S1191L mutation on the CFH gene was heterozygous in six people from the patient’s family with the aHUS. One of these family members is our patient with acute kidney injury, and the other two are followed at the Nephrology Clinic, Medeniyat University, Goztepe Training and Research Hospital, Istanbul, Turkey, due to chronic renal failure. The other three family members showed no evidence of renal failure. The index case had a history of six sibling deaths; three died of chronic renal failure. Plasmapheresis and fresh frozen plasma treatment were administered to our patient. When the patient showed no response to this treatment, eculizumab (ECZ) therapy was started. The study demonstrated that thorough family history should be taken in patients with the aHUS. These patients may have the familial type of the disease, and they should be screened genetically. Eculizumab should be the first choice in the treatment with plasmapheresis. It should be kept in mind that the use of ECZ as prophylaxis in posttransplant therapy is extremely important for preventing rejection.
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Piras R, Iatropoulos P, Bresin E, Todeschini M, Gastoldi S, Valoti E, Alberti M, Mele C, Galbusera M, Cuccarolo P, Benigni A, Remuzzi G, Noris M. Molecular Studies and an ex vivo Complement Assay on Endothelium Highlight the Genetic Complexity of Atypical Hemolytic Uremic Syndrome: The Case of a Pedigree With a Null CD46 Variant. Front Med (Lausanne) 2020; 7:579418. [PMID: 33224962 PMCID: PMC7670076 DOI: 10.3389/fmed.2020.579418] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/30/2020] [Indexed: 12/22/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is an ultra-rare disease characterized by microangiopathic hemolysis, thrombocytopenia, and renal impairment and is associated with dysregulation of the alternative complement pathway on the microvascular endothelium. Outcomes have improved greatly with pharmacologic complement C5 blockade. Abnormalities in complement genes (CFH, CD46, CFI, CFB, C3, and THBD), CFH–CFHR genomic rearrangements, and anti-FH antibodies have been reported in 40–60% of cases. The penetrance of aHUS is incomplete in carriers of complement gene abnormalities; and multiple hits, including the CFH–H3 and CD46GGAAC risk haplotypes and the CFHR1*B risk allele, as well as environmental factors, contribute to disease development. Here, we investigated the determinants of penetrance of aHUS associated with CD46 genetic abnormalities. We studied 485 aHUS patients and found CD46 rare variants (RVs) in about 10%. The c.286+2T>G RV was the most prevalent (13/485) and was associated with <30% penetrance. We conducted an in-depth study of a large pedigree including a proband who is heterozygous for the c.286+2T>G RV who experienced a severe form of aHUS and developed end-stage renal failure. The father and paternal uncle with the same variant in homozygosity and six heterozygous relatives are unaffected. Flow cytometry analysis showed about 50% reduction of CD46 expression on blood mononuclear cells from the heterozygous proband and over 90% reduction in cells from the proband's unaffected homozygous father and aunt. Further genetic studies did not reveal RVs in known aHUS-associated genes or common genetic modifiers that segregated with the disease. Importantly, a specific ex vivo test showed excessive complement deposition on endothelial cells exposed to sera from the proband, and also from his mother and maternal uncle, who do not carry the c.286+2T>G RV, indicating that they share a circulating defect that results in complement dysregulation on the endothelium. These results highlight the complexity of the genetics of aHUS and indicate that CD46 deficiency may not be enough to induce aHUS. We hypothesize that the proband inherited from his mother a genetic abnormality in a complement circulating factor that has not been identified yet, which synergized with the CD46 RV in predisposing him to the aHUS phenotype.
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Affiliation(s)
- Rossella Piras
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Paraskevas Iatropoulos
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Elena Bresin
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marta Todeschini
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Sara Gastoldi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Elisabetta Valoti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marta Alberti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Caterina Mele
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Miriam Galbusera
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Paola Cuccarolo
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Ariela Benigni
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marina Noris
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò,' Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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Wu H, Mao Z, Tan Y, Jiang Y, Yu J, Song L, Wu S, Sun M, Zhu L, Yu X, Zhang L, Yu F, Zhao MH. Genetic and functional analysis of two missense mutations in CD46 predispose to postpartum atypical hemolytic uremic syndrome. Clin Chim Acta 2020; 503:61-69. [PMID: 31945341 DOI: 10.1016/j.cca.2020.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 01/05/2020] [Accepted: 01/12/2020] [Indexed: 11/28/2022]
Abstract
Pregnancy associated atypical hemolytic uremic syndrome (p-aHUS) is a disease with a triad of hemolytic anemia, thrombocytopenia and acute renal failure, which might be attributed to the uncontrolled complement activation. Herein, we sequenced a postpartum-aHUS patient and found the two missense variants of CD46, a novel mutation (c.403G > C, p.G135R) from her father and a once reported mutation (c.293C > T, p.T98I) without expressional and functional tests from her mother. The G135R mutation caused a significantly reduced membrane expression of CD46 in peripheral blood lymphocyte and renal cells. The T98I mutation caused a mild decrease membrane expression of CD46 in peripheral blood lymphocyte cells. Moreover, the expressed G135R protein was in precursor form, indicating that this mutant was retained intracellularly. The C3b binding ability of T98I mutant was slightly decreased while the C4b binding ability is not significantly changed. The cofactor ability of the two mutants for factor I in the degradation of C3b was demonstrated to be impaired. This study reported the first case of a four-generation postpartum-aHUS pedigree with isolated CD46 variants and the detailed disease progression, treatment, and prognosis provided more meaningful information for the understanding the disease.
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Affiliation(s)
- Hao Wu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China.
| | - Zhaomin Mao
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100034, PR China.
| | - Ying Tan
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China.
| | - Yanfang Jiang
- Genetic Diagnosis Center, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China
| | - Jinyu Yu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China
| | - Li Song
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China
| | - Shan Wu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China.
| | - Mindan Sun
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China
| | - Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China.
| | - Xiaojuan Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China
| | - Li Zhang
- Department of Nephrology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China.
| | - Feng Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China; Department of Nephrology, Peking University International Hospital, Beijing 102206, PR China.
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100034, PR China.
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Bagga A, Khandelwal P, Mishra K, Thergaonkar R, Vasudevan A, Sharma J, Patnaik SK, Sinha A, Sethi S, Hari P, Dragon-Durey MA. Hemolytic uremic syndrome in a developing country: Consensus guidelines. Pediatr Nephrol 2019; 34:1465-1482. [PMID: 30989342 DOI: 10.1007/s00467-019-04233-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/06/2019] [Accepted: 03/07/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country. METHODS Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017. RESULTS An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted. CONCLUSIONS Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.
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Affiliation(s)
- Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Kirtisudha Mishra
- Department of Pediatrics, Chacha Nehru Bal Chikitsalya, New Delhi, India
| | - Ranjeet Thergaonkar
- Department of Pediatrics, Indian Naval Hospital Ship, Kalyani, Visakhapatnam, India
| | - Anil Vasudevan
- Department of Pediatric Nephrology, St. Johns Medical College and Hospital, Bengaluru, India
| | - Jyoti Sharma
- Department of Pediatrics, KEM Hospital, Pune, India
| | - Saroj Kumar Patnaik
- Department of Pediatrics, Army Hospital Research & Referral, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Sidharth Sethi
- Department of Nephrology, Medanta Hospital, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Marie-Agnes Dragon-Durey
- Laboratory of Immunology, Hopital Europeen Georges Pompidou, INSERM UMRS 1138, Paris Descartes University, Paris, France
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Khandelwal P, Birla S, Bhatia D, Puraswani M, Saini H, Sinha A, Hari P, Sharma A, Bagga A. Mutations in membrane cofactor protein ( CD46) gene in Indian children with hemolytic uremic syndrome. Clin Kidney J 2017; 11:198-203. [PMID: 29644059 PMCID: PMC5888602 DOI: 10.1093/ckj/sfx078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 06/13/2017] [Indexed: 12/13/2022] Open
Abstract
Background Mutations in the CD46 gene account for an important proportion of patients with atypical hemolytic uremic syndrome (aHUS) who characteristically show multiple relapses, no response to plasma exchange and low recurrence risk in allograft. We screened for mutations in CD46 in patients with and without circulating anti-factor H (FH) antibodies-associated aHUS. Methods We estimated CD46 surface expression by flow cytometry and sequenced the CD46 gene in 23 and 56 patients with and without circulating anti-FH antibodies, respectively. Human Splicing Finder and PolyPhen2 were used for in silico prediction of pathogenicity. Results Two novel and three known (c.286 +2T > G, c.104G > A and c.565T > G) mutations in CD46 were found in nine (11.4%) patients; one patient had a variant of unknown significance and two patients presented during the first year of life. Novel intronic (c.1127 + 46C > G) and exonic (c.911C > T) mutations are proposed to activate cryptic splicing sites or alter protein conformation. Markedly reduced CD46 surface expression was found in homozygous states in five patients. Conclusion Patients with mutations in CD46 present at all ages, including the first year of life. Mutations in intron 2, (c.286 +2T > G) may be a potential hot spot in Indian children. Flow cytometry for CD46 expression is a satisfactory screening tool enabling early diagnosis.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Shweta Birla
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Divya Bhatia
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Himanshi Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Arundhati Sharma
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
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Rabelo K, Trugilho MRO, Costa SM, Pereira BAS, Moreira OC, Ferreira ATS, Carvalho PC, Perales J, Alves AMB. The effect of the dengue non-structural 1 protein expression over the HepG2 cell proteins in a proteomic approach. J Proteomics 2016; 152:339-354. [PMID: 27826075 DOI: 10.1016/j.jprot.2016.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 10/14/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023]
Abstract
Dengue is an important mosquito borne viral disease in the world. Dengue virus (DENV) encodes a polyprotein, which is cleaved in ten proteins, including the non-structural protein 1 (NS1). In this work, we analyzed the effect of NS1 expression in one hepatic cell line, HepG2, through a shotgun proteomic approach. Cells were transfected with pcENS1 plasmid, which encodes the DENV2 NS1 protein, or the controls pcDNA3 (negative control) and pMAXGFP (GFP, a protein unrelated to dengue). Expression of NS1 was detected by immunofluorescence, western blot and flow cytometry. We identified 14,138 peptides that mapped to 4,756 proteins in all analyzed conditions. We found 41 and 81 differentially abundant proteins when compared to cells transfected with plasmids pcDNA3 and pMAXGFP, respectively. Besides, 107 proteins were detected only in the presence of NS1. We identified clusters of proteins involved mainly in mRNA process and viral RNA replication. Down regulation expression of one protein (MARCKS), identified by the proteomic analysis, was also confirmed by real time PCR in HepG2 cells infected with DENV2. Identification of proteins modulated by the presence of NS1 may improve our understanding of its role in virus infection and pathogenesis, contributing to development of new therapies and vaccines. BIOLOGICAL SIGNIFICANCE Dengue is an important viral disease, with epidemics in tropical and subtropical regions of the world. The disease is complex, with different manifestations, in which the liver is normally affected. The NS1 is found in infected cells associated with plasma membrane and secreted into the circulation as a soluble multimer. This protein is essential for virus viability, although its function is not elucidated. Some reports indicate that the NS1 can be used as a protective antigen for the development of a dengue vaccine, while others suggest its involvement in viral pathogenesis. In this work, we report an in-depth comprehensive proteomic profiling resulting from the presence of NS1 in HepG2 cells. These results can contribute to a better understanding of the NS1 role during infection.
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Affiliation(s)
- Kíssila Rabelo
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Monique R O Trugilho
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Simone M Costa
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Bernardo A S Pereira
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Otacílio C Moreira
- Laboratory of Molecular Biology and Endemic Diseases, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - André T S Ferreira
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Paulo C Carvalho
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz, Paraná, Brazil
| | - Jonas Perales
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Ada M B Alves
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil.
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