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1.
Proc Natl Acad Sci U S A ; 117(18): 9942-9951, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32321835

RESUMO

Genetic variants within complement factor H (CFH), a major alternative complement pathway regulator, are associated with the development of age-related macular degeneration (AMD) and other complementopathies. This is explained with the reduced binding of CFH or its splice variant factor H-like protein 1 (FHL-1) to self-ligands or altered self-ligands (e.g., malondialdehyde [MDA]-modified molecules) involved in homeostasis, thereby causing impaired complement regulation. Considering the critical role of CFH in inhibiting alternative pathway activation on MDA-modified surfaces, we performed an unbiased genome-wide search for genetic variants that modify the ability of plasma CFH to bind MDA in 1,830 individuals and characterized the mechanistic basis and the functional consequences of this. In a cohort of healthy individuals, we identified rs1061170 in CFH and the deletion of CFHR3 and CFHR1 as dominant genetic variants that modify CFH/FHL-1 binding to MDA. We further demonstrated that FHR1 and FHR3 compete with CFH for binding to MDA-epitopes and that FHR1 displays the highest affinity toward MDA-epitopes compared to CFH and FHR3. Moreover, FHR1 bound to MDA-rich areas on necrotic cells and prevented CFH from mediating its cofactor activity on MDA-modified surfaces, resulting in enhanced complement activation. These findings provide a mechanistic explanation as to why the deletion of CFHR3 and CFHR1 is protective in AMD and highlight the importance of genetic variants within the CFH/CFHR3/CFHR1 locus in the recognition of altered-self in tissue homeostasis.


Assuntos
Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Degeneração Macular/genética , Idoso , Fator H do Complemento/genética , Epitopos/genética , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Degeneração Macular/patologia , Masculino , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Ligação Proteica
2.
J Am Soc Nephrol ; 30(12): 2449-2463, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31575699

RESUMO

BACKGROUND: Atypical hemolytic uremic syndrome (HUS) is associated with high recurrence rates after kidney transplant, with devastating outcomes. In late 2011, experts in France recommended the use of highly individualized complement blockade-based prophylaxis with eculizumab to prevent post-transplant atypical HUS recurrence throughout the country. METHODS: To evaluate this strategy's effect on kidney transplant prognosis, we conducted a retrospective multicenter study from a large French nationwide registry, enrolling all adult patients with atypical HUS who had undergone complement analysis and a kidney transplant since January 1, 2007. To assess how atypical HUS epidemiology in France in the eculizumab era evolved, we undertook a population-based cohort study that included all adult patients with atypical HUS (n=397) between 2007 and 2016. RESULTS: The first study included 126 kidney transplants performed in 116 patients, 58.7% and 34.1% of which were considered to be at a high and moderate risk of atypical HUS recurrence, respectively. Eculizumab prophylaxis was used in 52 kidney transplants, including 39 at high risk of recurrence. Atypical HUS recurred after 43 (34.1%) of the transplants; in four cases, patients had received eculizumab prophylaxis and in 39 cases they did not. Use of prophylactic eculizumab was independently associated with a significantly reduced risk of recurrence and with significantly longer graft survival. In the second, population-based cohort study, the proportion of transplant recipients among patients with ESKD and atypical HUS sharply increased between 2012 and 2016, from 46.2% to 72.3%, and showed a close correlation with increasing eculizumab use among the transplant recipients. CONCLUSIONS: Results from this observational study are consistent with benefit from eculizumab prophylaxis based on pretransplant risk stratification and support the need for a rigorous randomized trial.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Síndrome Hemolítico-Urêmica Atípica/tratamento farmacológico , Inativadores do Complemento/uso terapêutico , Transplante de Rim , Adulto , Síndrome Hemolítico-Urêmica Atípica/epidemiologia , Síndrome Hemolítico-Urêmica Atípica/genética , Síndrome Hemolítico-Urêmica Atípica/cirurgia , Proteínas Inativadoras do Complemento C3b/genética , Proteínas do Sistema Complemento/análise , Feminino , França , Sobrevivência de Enxerto/efeitos dos fármacos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Proteínas Mutantes Quiméricas/genética , Cuidados Pré-Operatórios , Modelos de Riscos Proporcionais , Recidiva , Sistema de Registros , Estudos Retrospectivos , Prevenção Secundária
3.
Mol Med Rep ; 20(4): 3642-3648, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31485643

RESUMO

There is increasing evidence that human complement factor H­related protein 1 (CFHR1) plays a crucial role in the development of malignant diseases. However, few studies have identified the roles of CFHR1 in the occurrence and prognosis of lung adenocarcinoma (LADC). In the present study, comprehensive bioinformatic analyses of data obtained from the Oncomine platform, UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA) demonstrated that CFHR1 expression is significantly reduced in both LADC tissues and cancer cells. The patients presenting with downregulation of CFHR1 had significantly lower overall survival (OS) and post progression survival (PPS) times. Through analysis of the datasets from Gene Expression Omnibus database, we found that the compound actinomycin D promoted CFHR1 expression, further displaying the cytotoxic effect in the LADC cell line A549. In addition, the expression level of CFHR1 in the cisplatin­resistant LADC cell line CDDP­R (derived from H460) was also significantly reduced. Our research demonstrated that low levels of CFHR1 are specifically found in LADC samples, and CFHR1 could serve as a potential therapeutic target for this subset of lung cancers. Determination of the detailed roles of CFHR1 in LADC biology could provide insightful information for further investigations.


Assuntos
Adenocarcinoma de Pulmão/genética , Proteínas Inativadoras do Complemento C3b/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/genética , Células A549 , Adenocarcinoma de Pulmão/diagnóstico , Regulação para Baixo , Feminino , Redes Reguladoras de Genes , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Prognóstico
4.
J Clin Immunol ; 39(3): 336-345, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30945073

RESUMO

A homozygous 83-kb deletion encompassing the genes for complement factor-H-related proteins 1 and 3 (FHR 1, FHR3) is known as a risk factor for some immune inflammatory disorders. However, the functional relevance of this FHR1/3 deletion is relatively unexplored. Globally, healthy populations of all ethnic groups tested show an 8-10% prevalence of homozygosity for this deletion polymorphism. We have begun to compare the peripheral leucocyte phenotype and functionality between FHR1/3-/- and FHR1/3+/+ healthy adult individuals. We report that the two groups show significant differences in their peripheral blood innate leucocyte subset composition, although the adaptive immune subsets are similar between them. Specifically, FHR1/3-/- individuals show higher frequencies of patrolling monocytes and lower frequencies of classical monocytes than FHR1/3+/+ individuals. Similarly, FHR1/3-/- individuals show higher frequencies of plasmacytoid dendritic cells (pDCs) and lower frequencies of myeloid DCs (mDCs) than FHR1/3+/+ individuals. Notably, classical monocytes specifically showed cell-surface-associated factor H (FH), and cells from the FHR1/3-/- group had somewhat higher surface-associated FH levels than those from FHR1/3+/+ individuals. FHR1/3-/- monocytes also showed elevated secretion of TNF-α, IL-1ß, and IL-10 in response to TLR7/8 or TLR4 ligands. Similarly, FHR1/3-/- mDCs and pDCs showed modest but evident hyper-responsiveness to TLR ligands. Our findings, that the FHR1/3-/- genotype is associated with significant alterations of both the relative prominence and the functioning of monocyte and DC subsets, may be relevant in understanding the mechanism underlying the association of the genotype with immune inflammatory disorders.


Assuntos
Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Genótipo , Doenças do Sistema Imunitário/genética , Inflamação/genética , Leucócitos Mononucleares/fisiologia , Deleção de Sequência/genética , Adulto , Células Cultivadas , Citocinas , Feminino , Homozigoto , Humanos , Imunidade Celular , Masculino , Pessoa de Meia-Idade , Fenótipo , Adulto Jovem
5.
Nephron ; 142(3): 264-270, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30889567

RESUMO

A 6-month-old boy presented with acute renal failure, thrombocytopenia, and severe non-immune hemolytic anemia. Infection by Shiga-like toxin-producing Escherichia coli and other causes of microangiopathic hemolysis were ruled out, leading to a diagnosis of atypical hemolytic uremic syndrome (aHUS). Neither pathogenic variants in HUS-associated genes nor anti-factor H antibodies were identified. Copy number variation analysis uncovered 4 copies of complement factor H related genes, CFHR1-CFHR4, conceivably leading to higher than normal levels of the corresponding proteins. However, this abnormality was also found in the healthy relatives, neither explaining the disease nor the excessive complement deposition on endothelial cells detected by an ex-vivo test. Whole-exome sequencing revealed a pathogenic homozygous variant in GRHPR encoding the glyoxylate and hydroxypyruvate reductase. Recessive GRHPR mutations cause primary hyperoxaluria type 2 (PH2). The presence of renal calculi in the patient and elevated oxalate levels in the urine were consistent with the genetic diagnosis of PH2. We hypothesize that, in this patient, hyperoxaluria caused by the GRHPR genetic defect triggered endothelial perturbation and complement activation, which was amplified by impaired factor H regulatory activity due to the increased -CFHR1-CFHR4 copy numbers, resulting in aHUS.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/etiologia , Hiperoxalúria Primária/complicações , Oxirredutases do Álcool/genética , Apolipoproteínas/genética , Ativação do Complemento , Proteínas Inativadoras do Complemento C3b/genética , Humanos , Hiperoxalúria Primária/genética , Lactente , Masculino , Sequenciamento Completo do Exoma
7.
Am J Med Sci ; 356(5): 492-498, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30177262

RESUMO

Thrombotic microangiopathy (TMA) may result from a variety of clinical conditions, including thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome and complement-mediated hemolytic uremic syndrome. Thrombocytopenic purpura is diagnosed when ADAMTS13 is <10%, while a diagnosis of Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome is made with the evidence of infection by Shiga toxin-producing Escherichia coli. Diagnosis of complement-mediated hemolytic uremic syndrome is not dependent on a specific laboratory test and is a diagnosis of exclusion. TMA is a rare disease and finding individuals that have more than 1 concurrent etiology leading to TMA is even more rare. Here we describe the presentation and management of an individual with CFHR1 deletion-associated TMA also found to have a positive stool Shiga toxin. We discuss the significance of Shiga toxin in serving as a trigger for development of TMA in an individual predisposed to development of TMA due to presence of a homozygous deletion in CFHR1.


Assuntos
Sequência de Bases/efeitos dos fármacos , Proteínas Inativadoras do Complemento C3b/genética , Deleção de Sequência/efeitos dos fármacos , Toxina Shiga/efeitos adversos , Microangiopatias Trombóticas/genética , Adulto , Proteínas Inativadoras do Complemento C3b/metabolismo , Feminino , Homozigoto , Humanos , Microangiopatias Trombóticas/microbiologia
8.
PLoS One ; 13(8): e0200739, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30071029

RESUMO

Sphingolipids are bioactive molecules associated with oxidative stress, inflammation, and neurodegenerative diseases, but poorly studied in the context of age-related macular degeneration (AMD), a prevalent sight-threatening disease of the ageing retina. Here, we found higher serum levels of hexosylceramide (HexCer) d18:1/16:0 in patients with choroidal neovascularization (CNV) and geographic atrophy (GA), two manifestations of late stage AMD, and higher ceramide (Cer) d18:1/16:0 levels in GA patients. A sensitivity analysis of genetic variants known to be associated with late stage AMD showed that rs1061170 (p.Y402H) in the complement factor H (CFH) gene influences the association of Cer d18:1/16:0 with GA. To understand the possible influence of this genetic variant on ceramide levels, we established a cell-based assay to test the modulation of genes in the ceramide metabolism by factor H-like protein 1 (FHL-1), an alternative splicing variant of CFH that also harbors the 402 residue. We first showed that malondialdehyde-acetaldehyde adducts, an oxidation product commonly found in AMD retinas, induces an increase in ceramide levels in WERI-Rb1 cells in accordance with an increased expression of ceramide synthesis genes. Then, we observed that cells exposed to the non-risk FHL-1:Y402, but not the risk associated variant FHL-1:H402 or full-length CFH, downregulated ceramide synthase 2 and ceramide glucosyltransferase gene expression. Together, our findings show that serum ceramide and hexosylceramide species are altered in AMD patients and that ceramide levels may be influenced by AMD associated risk variants.


Assuntos
Ceramidas/sangue , Degeneração Macular/diagnóstico , Esfingomielinas/sangue , Idoso , Idoso de 80 Anos ou mais , Linhagem Celular , Ceramidas/metabolismo , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/genética , Proteínas Inativadoras do Complemento C3b/genética , Fator H do Complemento/genética , Regulação para Baixo , Variação Genética , Glucosiltransferases/genética , Humanos , Degeneração Macular/genética , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Isoformas de Proteínas/genética , Fatores de Risco , Esfingosina N-Aciltransferase/genética , Proteínas Supressoras de Tumor/genética
9.
Pediatr Nephrol ; 33(8): 1437-1442, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29728803

RESUMO

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is caused by the abundance of uncleaved ultralarge von Willebrand factor multimers (ULvWF) due to acquired (autoantibody-mediated) or congenital vWF protease ADAMTS13 deficiency. Current treatment recommendations include plasma exchange therapy and immunosuppression for the acquired form and (fresh) frozen plasma for congenital TTP. CASE-DIAGNOSIS/TREATMENT: A previously healthy, 3-year-old boy presented with acute microangiopathic hemolytic anemia, thrombocytopenia, erythrocyturia and mild proteinuria, but normal renal function, and elevated circulating sC5b-9 levels indicating complement activation. He was diagnosed with atypical hemolytic uremic syndrome and treated with a single dose of eculizumab, followed by prompt resolution of all hematological parameters. However, undetectably low plasma ADAMTS13 activity in the pre-treatment sample, associated with inhibitory ADAMTS13 antibodies, subsequently changed the diagnosis to acquired TTP. vWF protease activity normalized within 15 months without further treatment, and the patient remained in long-term clinical and laboratory remission. Extensive laboratory workup revealed a homozygous deletion of CFHR3/1 negative for anti-CFH antibodies, but no mutations of ADAMTS13, (other) alternative pathway of complement regulators or coagulation factors. CONCLUSIONS: This case, together with a previous report of a boy with congenital TTP (Pecoraro et al. Am J Kidney Dis 66:1067, 2015), strengthens evolving in-vitro and ex-vivo evidence that ULvWF interferes with complement regulation and contributes to the TTP phenotype. Comprehensive, prospective complement studies in patients with TTP may lead to a better pathophysiological understanding and novel treatment approaches for acquired or congenital forms.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Inativadores do Complemento/uso terapêutico , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Anticorpos Monoclonais Humanizados/farmacologia , Proteínas Sanguíneas/imunologia , Pré-Escolar , Ativação do Complemento/efeitos dos fármacos , Ativação do Complemento/imunologia , Inativadores do Complemento/farmacologia , Humanos , Masculino , Marrocos , Púrpura Trombocitopênica Trombótica/sangue , Púrpura Trombocitopênica Trombótica/diagnóstico , Púrpura Trombocitopênica Trombótica/imunologia , Resultado do Tratamento
10.
Dev Comp Immunol ; 84: 241-249, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29496498

RESUMO

Complement is a complex innate immune surveillance system, playing a key role in host homeostasis, inflammation, and in the defense against pathogens. Complement regulators are crucial to prevent the injudicious production of these mediators and potential injury to self tissues. Here, we identified the complement factor H (CFH) and its related gene 2 (CFHR2) homologs from large yellow croaker (Larimichthys crocea), named LcCfh and LcCfhr2, respectively. The deduced LcCfh and LcCfhr2 proteins shared significant structural similarities and identified codes for a polypeptide consisting of various numbers of highly conserved SCR domains. LcCfh, LcCfhr1 and LcCfhr2 genes were detected in all examined tissues with predominantly expressions in liver, spleen and kidney, and their expressions all increased upon Vibrio alginolyticus challenge. In vitro assays showed that recombinant LcCfh was likely to act as a cofactor of CFI and played a negative regulation role in complement system, when recombinant LcCfhr2 seemed to play mechanisms independent of the activity of CFH. Both recombinant LcCfh and LcCfhr2 took participate in inflammatory reaction despite of the inequal ability to mediate pro-inflammation response. These data provide a new insight into the functional activities of teleost complement system.


Assuntos
Proteínas Inativadoras do Complemento C3b/metabolismo , Fator H do Complemento/metabolismo , Proteínas de Peixes/metabolismo , Inflamação/metabolismo , Fígado/fisiologia , Perciformes/imunologia , Vibrioses/metabolismo , Vibrio alginolyticus/imunologia , Animais , Clonagem Molecular , Ativação do Complemento , Proteínas Inativadoras do Complemento C3b/genética , Fator H do Complemento/genética , Proteínas de Peixes/genética , Imunidade Inata
11.
JCI Insight ; 3(6)2018 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-29563339

RESUMO

BACKGROUND: HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome is a severe variant of hypertensive disorders of pregnancy affecting approximately 1% of all pregnancies, and has significant maternal and fetal morbidity. Previously, we showed that upregulation of the alternative pathway of complement (APC) plays a role in HELLP syndrome. We hypothesize that HELLP syndrome follows a 2-hit disease model similar to atypical hemolytic uremic syndrome (aHUS), requiring both genetic susceptibility and an environmental risk factor. Our objective was to perform a comparative analysis of the frequency of APC activation and germline mutations in affected women and to create a predictive model for identifying HELLP syndrome. METHODS: Pregnant women with HELLP syndrome, and healthy controls after 23 weeks of gestation were recruited, along with aHUS and thrombotic thrombocytopenic purpura participants. We performed a functional assay, the mHam, and targeted genetic sequencing in all groups. RESULTS: Significantly more participants with rare germline mutations in APC genes were present in the HELLP cohort compared with controls (46% versus 8%, P = 0.01). In addition, significantly more HELLP participants were positive for the mHam when compared with controls (62% versus 16%, P = 0.009). Testing positive for both a germline mutation and the mHam was highly predictive for the diagnosis of HELLP syndrome. CONCLUSION: HELLP syndrome is characterized by both activation of the APC and frequent germline mutations in APC genes. Similar to aHUS, treatment via complement inhibition to mitigate maternal and fetal morbidity and mortality may be possible. FUNDING: National Heart Lung and Blood Institute grants T32HL007525 and R01HL133113.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/complicações , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa , Síndrome HELLP/etiologia , Síndrome HELLP/genética , Adolescente , Adulto , Idoso , Análise de Variância , Proteínas Sanguíneas/genética , Estudos de Casos e Controles , Proteínas Inativadoras do Complemento C3b/genética , Proteínas Inativadoras do Complemento/genética , Feminino , Síndrome HELLP/metabolismo , Humanos , Pessoa de Meia-Idade , Gravidez , Estudos Prospectivos , Púrpura Trombocitopênica Trombótica/complicações , Fatores de Risco , Adulto Jovem
12.
BMJ Case Rep ; 20182018 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-29440240

RESUMO

A 17-year-old girl presented with fever, myalgia, vomiting for 1 month and oliguria and dyspnoea for 4 days. She was tachycardic,hypertensive, with pedal oedema and decreased breath sounds. She had high serum creatinine (3 mg/dL), anaemia, thrombocytopenia, leucocytosis and eosinophilia with schistocytes. Lactate dehydrogenase, transaminases were high , with low haptoglobin and high ferritin (5269 ng/mL). Complement C3/C4 and fibrinogen were normal. Urinalysis showed large blood and protein and stool studies were negative. Her ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) was normal. Kidney biopsy showed acute interstitial nephritis (AIN) in addition to thrombotic angiopathy. The differentials - haemolytic uraemic syndrome (HUS), thrombotic thrombocytopenia (TTP) and haemophagocytic lymphohistiocytosis (HLH) were ruled out. Her genetic testing was abnormal for large CFHR1-CFHR3 homozygous deletion and heterozygous missense variant in exon 2 of DGKE making the diagnosis of atypical HUS. She received eculizumab and was discharged on oral steroids for AIN and biweekly eculizumab infusions with excellent recovery.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/complicações , Síndrome Hemolítico-Urêmica Atípica/diagnóstico , Febre/etiologia , Mialgia/etiologia , Adolescente , Anticorpos Monoclonais Humanizados/uso terapêutico , Síndrome Hemolítico-Urêmica Atípica/tratamento farmacológico , Síndrome Hemolítico-Urêmica Atípica/genética , Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Feminino , Deleção de Genes , Humanos , Imunossupressores/uso terapêutico , Resultado do Tratamento , Urinálise
13.
J Am Soc Nephrol ; 29(4): 1141-1153, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29335241

RESUMO

The complement system is essential for host defense, but uncontrolled complement system activation leads to severe, mostly renal pathologies, such as atypical hemolytic uremic syndrome or C3 glomerulopathy. Here, we investigated a novel combinational approach to modulate complement activation by targeting C3 and the terminal pathway simultaneously. The synthetic fusion protein MFHR1 links the regulatory domains of complement factor H (FH) with the C5 convertase/C5b-9 inhibitory fragment of the FH-related protein 1. In vitro, MFHR1 showed cofactor and decay acceleration activity and inhibited C5 convertase activation and C5b-9 assembly, which prevented C3b deposition and reduced C3a/C5a and C5b-9 generation. Furthermore, this fusion protein showed the ability to escape deregulation by FH-related proteins and form multimeric complexes with increased inhibitory activity. In addition to substantially inhibiting alternative and classic pathway activation, MFHR1 blocked hemolysis mediated by serum from a patient with aHUS expressing truncated FH. In FH-/- mice, MFHR1 administration augmented serum C3 levels, reduced abnormal glomerular C3 deposition, and ameliorated C3 glomerulopathy. Taking the unique design of MFHR1 into account, we suggest that the combination of proximal and terminal cascade inhibition together with the ability to form multimeric complexes explain the strong inhibitory capacity of MFHR1, which offers a novel basis for complement therapeutics.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/sangue , Proteínas Sanguíneas/deficiência , Proteínas Inativadoras do Complemento C3b/genética , Inativadores do Complemento/farmacologia , Terapia de Alvo Molecular , Proteínas Recombinantes de Fusão/farmacologia , Animais , Síndrome Hemolítico-Urêmica Atípica/genética , Síndrome Hemolítico-Urêmica Atípica/imunologia , Complemento C3/metabolismo , Convertases de Complemento C3-C5/antagonistas & inibidores , Convertases de Complemento C3-C5/metabolismo , Complemento C3b/antagonistas & inibidores , Proteínas Inativadoras do Complemento C3b/deficiência , Complemento C5/metabolismo , Fator H do Complemento/genética , Inativadores do Complemento/isolamento & purificação , Inativadores do Complemento/uso terapêutico , Complexo de Ataque à Membrana do Sistema Complemento/biossíntese , Via Alternativa do Complemento , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Glomérulos Renais/química , Glomérulos Renais/patologia , Camundongos , Camundongos Knockout , Domínios Proteicos , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/uso terapêutico
14.
Kidney Int ; 93(2): 450-459, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28911789

RESUMO

Pregnancy-associated atypical hemolytic uremic syndrome (aHUS) refers to the thrombotic microangiopathy resulting from uncontrolled complement activation during pregnancy or the postpartum period. Pregnancy-associated aHUS is a devastating disease for which there is a limited clinical understanding and treatment experience. Here we report a retrospective study to analyze the clinical and prognostic data of 22 cases of pregnancy-associated aHUS from the Spanish aHUS Registry under different treatments. Sixteen patients presented during the first pregnancy and as many as nine patients required hemodialysis at diagnosis. Identification of inherited complement abnormalities explained nine of the 22 cases, with CFH mutations and CFH to CFHR1 gene conversion events being the most prevalent genetic alterations associated with this disorder (66%). In thirteen of the cases, pregnancy complications were sufficient to trigger a thrombotic microangiopathy in the absence of genetic or acquired complement alterations. The postpartum period was the time with highest risk to develop the disease and the group shows an association of cesarean section with pregnancy-associated aHUS. Seventeen patients underwent plasma treatments with a positive renal response in only three cases. In contrast, ten patients received eculizumab with an excellent renal response in all, independent of carrying or not inherited complement abnormalities. Although the cohort is relatively small, the data suggest that pregnancy-associated aHUS is not different from other types of aHUS and suggest the efficacy of eculizumab treatment over plasma therapies. This study may be useful to improve prognosis in this group of aHUS patients.


Assuntos
Síndrome Hemolítico-Urêmica Atípica , Complicações na Gravidez , Microangiopatias Trombóticas , Adulto , Anticorpos Monoclonais Humanizados/uso terapêutico , Síndrome Hemolítico-Urêmica Atípica/epidemiologia , Síndrome Hemolítico-Urêmica Atípica/genética , Síndrome Hemolítico-Urêmica Atípica/imunologia , Síndrome Hemolítico-Urêmica Atípica/terapia , Cesárea , Ativação do Complemento , Proteínas Inativadoras do Complemento C3b/genética , Fator H do Complemento/genética , Feminino , Conversão Gênica , Humanos , Imunossupressores/uso terapêutico , Mutação , Paridade , Troca Plasmática , Período Pós-Parto , Gravidez , Complicações na Gravidez/epidemiologia , Complicações na Gravidez/genética , Complicações na Gravidez/imunologia , Complicações na Gravidez/terapia , Sistema de Registros , Diálise Renal , Estudos Retrospectivos , Fatores de Risco , Espanha/epidemiologia , Microangiopatias Trombóticas/epidemiologia , Microangiopatias Trombóticas/genética , Microangiopatias Trombóticas/imunologia , Microangiopatias Trombóticas/terapia , Resultado do Tratamento
15.
J Immunol ; 200(1): 316-326, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29187587

RESUMO

Factor H (FH) is a key alternative pathway regulator that controls complement activation both in the fluid phase and on specific cell surfaces, thus allowing the innate immune response to discriminate between self and foreign pathogens. However, the interrelationships between FH and a group of closely related molecules, designated the FH-related (FHR) proteins, are currently not well understood. Whereas some studies have suggested that human FHR proteins possess complement regulatory abilities, recent studies have shown that FHR proteins are potent deregulators. Furthermore, the roles of the FHR proteins have not been explored in any in vivo models of inflammatory disease. In this study, we report the cloning and expression of recombinant mouse FH and three FHR proteins (FHR proteins A-C). Results from functional assays show that FHR-A and FHR-B proteins antagonize the protective function of FH in sheep erythrocyte hemolytic assays and increase cell-surface C3b deposition on a mouse kidney proximal tubular cell line (TEC) and a human retinal pigment epithelial cell line (ARPE-19). We also report apparent KD values for the binding interaction of mouse C3d with mouse FH (3.85 µM), FHR-A (136 nM), FHR-B (546 nM), and FHR-C (1.04 µM), which directly correlate with results from functional assays. Collectively, our work suggests that similar to their human counterparts, a subset of mouse FHR proteins have an important modulatory role in complement activation. Further work is warranted to define the in vivo context-dependent roles of these proteins and determine whether FHR proteins are suitable therapeutic targets for the treatment of complement-driven diseases.


Assuntos
Proteínas Inativadoras do Complemento C3b/genética , Fator H do Complemento/metabolismo , Via Alternativa do Complemento , Rim/fisiologia , Epitélio Pigmentado da Retina/fisiologia , Animais , Linhagem Celular , Clonagem Molecular , Proteínas Inativadoras do Complemento C3b/metabolismo , Hemólise , Humanos , Imunidade Inata , Imunomodulação , Camundongos , Receptores de Complemento/metabolismo , Tolerância a Antígenos Próprios
16.
J Pediatr Hematol Oncol ; 40(8): e544-e546, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-28991129

RESUMO

Complement system dysregulation, such as complement Factor H (CFH) autoantibodies and deletions in CFH-related (CFHR) genes 3 and 1, might cause transplant-associated thrombotic microangiopathy (TA-TMA). The use of eculizumab, a terminal complement inhibitor, could be a targeted therapy for TA-TMA. We report a 1-year-old girl who developed TA-TMA, just after autologous peripheral blood stem cell transplantation in neuroblastoma therapy. Eculizumab improved TA-TMA. Investigation for the complement alternative pathway showed a heterozygous CFHR3-CFHR1 gene deletion, which is involved in complement activation. The patient might develop TA-TMA as a result of complement regulatory gene mutation.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Deleção de Genes , Neuroblastoma , Transplante de Células-Tronco/efeitos adversos , Microangiopatias Trombóticas , Autoenxertos , Feminino , Heterozigoto , Humanos , Lactente , Neuroblastoma/genética , Neuroblastoma/terapia , Microangiopatias Trombóticas/tratamento farmacológico , Microangiopatias Trombóticas/etiologia , Microangiopatias Trombóticas/genética
17.
J Am Soc Nephrol ; 29(1): 240-249, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28993505

RESUMO

Atypical hemolytic uremic syndrome (aHUS), a rare form of thrombotic microangiopathy caused by complement pathogenic variants, mainly affects the kidney microvasculature. A retrospective genetic analysis in our aHUS cohort (n=513) using multiple ligation probe amplification uncovered nine unrelated patients carrying a genetic abnormality in the complement factor H related 1 gene (CFHR1) that originates by recurrent gene conversion events between the CFH and CFHR1 genes. The novel CFHR1 mutants encode an FHR-1 protein with two amino acid substitutions, L290S and A296V, converting the FHR-1 C terminus into that of factor H (FH). Next-generation massive-parallel DNA sequencing (NGS) analysis did not detect these genetic abnormalities. In addition to the CFHR1 mutant, six patients carried the previously uncharacterized CFH-411T variant. In functional analyses, the mutant FHR-1 protein strongly competed the binding of FH to cell surfaces, impairing complement regulation, whereas the CFH-411T polymorphism lacked functional consequences. Carriers of the CFHR1 mutation presented with severe aHUS during adulthood; 57% of affected women in this cohort presented during the postpartum period. Analyses in patients and unaffected carriers showed that FH plasma levels determined by the nonmutated chromosome modulate disease penetrance. Crucially, in the activated endothelial (HMEC-1) cell assay, reduced FH plasma levels produced by the nonmutated chromosome correlated inversely with impairment of complement regulation, measured as C5b-9 deposition. Our data advance understanding of the genetic complexities underlying aHUS, illustrate the importance of performing functional analysis, and support the use of complementary assays to disclose genetic abnormalities not revealed by current NGS analysis.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/genética , Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Fator H do Complemento/genética , Conversão Gênica , Adulto , Ligação Competitiva , Linhagem Celular , Fator H do Complemento/metabolismo , Complexo de Ataque à Membrana do Sistema Complemento/metabolismo , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Penetrância , Estudos Retrospectivos , Análise de Sequência de DNA/métodos , Adulto Jovem
18.
J Am Soc Nephrol ; 29(2): 661-669, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29114042

RESUMO

Activation of complement through the alternative pathway has a key role in the pathogenesis of IgA nephropathy (IgAN). Large, international, genome-wide association studies have shown that deletion of complement factor H-related genes 1 and 3 (CFHR3,1Δ) is associated with a reduced risk of developing IgAN, although the prognostic value of these deletions in IgAN remains unknown. Here, we compared the renal outcomes of patients with IgAN according to their CFHR3,1Δ genotype. This retrospective, monocentric cohort study included 639 white patients with biopsy-proven IgAN since 1979 (mean age at diagnosis, 40.1 years; median follow-up, 132 months). We determined the number of CFHR3 and CFHR1 gene copies by quantitative PCR and collected clinical and biologic data by reviewing the patients' medical records. In all, 30.5% of the patients were heterozygous and 4% were homozygous for CFHR3,1Δ We did not detect an association between CFHR3,1Δ and age, eGFR, urinary protein excretion rate, or the presence of hypertension or hematuria at the time of diagnosis. The mean intensities of immune IgA, IgG, and C3 deposits were lower in the group with heterozygous or homozygous gene deletions than in those with no deletion. However, CFHR3,1Δ did not associate with progression to stage 3 CKD or renal death. In conclusion, the CFHR3,1Δ genotype did not associate with progression toward CKD stages 3 and 5 in our white population of patients with IgAN, although it did associate with a reduced level of glomerular immune deposits.


Assuntos
Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Mesângio Glomerular/metabolismo , Glomerulonefrite por IGA/genética , Glomerulonefrite por IGA/imunologia , Adulto , Idoso , Progressão da Doença , Grupo com Ancestrais do Continente Europeu , Feminino , Dosagem de Genes , Taxa de Filtração Glomerular , Glomerulonefrite por IGA/fisiopatologia , Heterozigoto , Homozigoto , Humanos , Imunoglobulina A/metabolismo , Imunoglobulina G/metabolismo , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Deleção de Sequência , Adulto Jovem
19.
Clin Rheumatol ; 36(12): 2859-2867, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28905254

RESUMO

The association of thrombotic microangiopathy (TMA) with systemic lupus erythematosus (SLE) has been described in 0.5 to 10% of cases, and patients present worse outcome. TMA is described as the association of microangiopathic hemolytic anemia, thrombocytopenia, and an organ injury, frequently the kidney. This study describes a successful case of use of eculizumab in a patient with SLE and TMA refractory to standard therapy, and provides a literature review. Case description and search in PubMed and MEDLINE using systemic lupus erythemathous and/or antiphospholipid syndrome (APS) and eculizumab retrieved 15 case reports. Eighteen-year-old female presented acute renal failure and TMA and was diagnosed with SLE. Steroids and IV cyclophosphamide were started together with plasma exchange. After 55 days, she still persisted with microangiopathic anemia, thrombocytopenia, and anuria, and eculizumab was introduced. She had rapid improvement in hematological parameters, and dialysis was discontinued 25 days after the first dose. Genetic analysis showed large heterozygous deletion encompassing the entire CFHR1 and CFHR3, a finding previously associated with patients presenting atypical hemolytic-uremic syndrome (aHUS). Twenty patients who received eculizumab with SLE and/or APS have been published to date: 11 were female and mean age at presentation was 31 years. Seven out of the 20 patients presented only SLE, 5 patients only APS and 8 patients both SLE and APS. Eighteen patients underwent plasma exchange, with a mean of 20 (4-120) sessions per patient. Thirteen patients received rituximab. Hematological response was evident in 100% and kidney recovery in 85% of patients. The terminal complement blockade with eculizumab is an optional treatment for patients with SLE and/or APS presenting TMA and refractory to current immunosuppression therapies. Genetic testing may help recognize patients with aHUS and SLE/APS and therefore help to determine length of treatment with eculizumab.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Microangiopatias Trombóticas/tratamento farmacológico , Adolescente , Proteínas Sanguíneas/genética , Proteínas Inativadoras do Complemento C3b/genética , Feminino , Humanos , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/genética , Deleção de Sequência , Microangiopatias Trombóticas/etiologia , Microangiopatias Trombóticas/genética , Resultado do Tratamento
20.
Kidney Int ; 92(4): 876-887, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28729035

RESUMO

The intrinsic similarity shared between the members of the complement factor H family, which comprises complement factor H and five complement factor H-related (CFHR) genes, leads to various recombination events. In turn these events lead to deletions of some genes or abnormal proteins, which are found in patients with atypical hemolytic uremic syndrome or C3 glomerulopathies. Here we describe a novel genetic rearrangement generated from a heterozygous deletion spanning 146 Kbp involving multiple CFHR genes leading to a CFHR1-R5 hybrid protein. This deletion was found in four family members presenting with a familial dominant glomerulopathy histologically classified as an overlap of dense deposit disease and C3 glomerulonephritis. Affected patients exhibited permanently low C3 and factor B levels and high amounts of activation fragments sC5b9 and Bb, indicating a systemic alternative pathway dysregulation. The abnormal protein, characterized by Western blot and immunoprecipitation, was shown to circulate in association with CFHR1 and CFHR2, attributable to its two N-terminal dimerization motifs. The presence of this protein is associated with a perturbation of Factor H activity on the C3 convertase decay. Thus, our study highlights the role of CFHRs in the physiopathology of C3 glomerulopathies and stresses the importance of screening CFHRs in all familial C3 glomerulopathies. Such hybrids described till now were always associated with familial forms.


Assuntos
Síndrome Hemolítico-Urêmica Atípica/genética , Complemento C3/análise , Proteínas Inativadoras do Complemento C3b/genética , Proteínas do Sistema Complemento/genética , Glomerulonefrite Membranoproliferativa/genética , Adulto , Síndrome Hemolítico-Urêmica Atípica/sangue , Síndrome Hemolítico-Urêmica Atípica/patologia , Síndrome Hemolítico-Urêmica Atípica/terapia , Criança , Convertases de Complemento C3-C5/metabolismo , Fator B do Complemento/análise , Fator H do Complemento/metabolismo , Via Alternativa do Complemento/genética , Feminino , Fusão Gênica , Rearranjo Gênico , Glomerulonefrite Membranoproliferativa/sangue , Glomerulonefrite Membranoproliferativa/patologia , Glomerulonefrite Membranoproliferativa/terapia , Humanos , Lactente , Rim/patologia , Masculino , Linhagem , Deleção de Sequência
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