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Krüger A, Fabrizius A, Mikkelsen B, Siebert U, Folkow LP, Burmester T. Transcriptome analysis reveals a high aerobic capacity in the whale brain. Comp Biochem Physiol A Mol Integr Physiol 2019; 240:110593. [PMID: 31676411 DOI: 10.1016/j.cbpa.2019.110593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/30/2019] [Accepted: 10/22/2019] [Indexed: 01/04/2023]
Abstract
The brain of diving mammals is repeatedly exposed to low oxygen conditions (hypoxia) that would have caused severe damage to most terrestrial mammals. Some whales may dive for >2 h with their brain remaining active. Many of the physiological adaptations of whales to diving have been investigated, but little is known about the molecular mechanisms that enable their brain to survive sometimes prolonged periods of hypoxia. Here, we have used an RNA-Seq approach to compare the mRNA levels in the brains of whales with those of cattle, which serves as a terrestrial relative. We sequenced the transcriptomes of the brains from cattle (Bos taurus), killer whale (Orcinus orca), and long-finned pilot whale (Globicephala melas). Further, the brain transcriptomes of cattle, minke whale (Balaenoptera acutorostrata) and bowhead whale (Balaena mysticetus), which were available in the databases, were included. We found a high expression of genes related to oxidative phosphorylation and the respiratory electron chain in the whale brains. In the visual cortex of whales, transcripts related to the detoxification of reactive oxygen species were more highly expressed than in the visual cortex of cattle. These findings indicate a high oxidative capacity in the whale brain that might help to maintain aerobic metabolism in periods of reduced oxygen availability during dives.
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Affiliation(s)
- Alena Krüger
- Institute of Zoology, University of Hamburg, Germany.
| | | | | | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, D-25761 Büsum, Germany.
| | - Lars P Folkow
- University of Tromsø - The Arctic University of Norway, NO-9037 Tromsø, Norway.
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Batu ED, Koşukcu C, Taşkıran E, Sahin S, Akman S, Sözeri B, Ünsal E, Bilginer Y, Kasapcopur O, Alikaşifoğlu M, Ozen S. Whole Exome Sequencing in Early-onset Systemic Lupus Erythematosus. J Rheumatol 2018; 45:1671-1679. [PMID: 30008451 DOI: 10.3899/jrheum.171358] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2018] [Indexed: 12/16/2022]
Abstract
Objective.Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder. Early-onset, familial, and/or syndromic SLE may reveal monogenic pathologies. The aim of this study was to examine genetic associations in patients with early-onset or familial SLE.Methods.We enrolled 7 SLE cases (from different families) with disease onset ≤ 5 years of age and family history consistent with an autosomal recessive inheritance. Whole exome sequencing (WES) was performed in 6 index cases. Suspected variants were confirmed by Sanger sequencing. We did not perform WES in 1 patient who had features similar to the first 3 cases; only the exons of C1QA, C1QB, and C1QC were screened with Sanger sequencing.Results.We demonstrated 2 novel and 3 previously reported variants in genes associated with SLE: a homozygous non-sense alteration (c.622C>T/p.Gln208Ter) in C1QA in 2 patients; homozygous non-sense alteration (c.79C>T/p.Gln27Ter) in C1QC in 1 (novel variant); homozygous missense alteration (c.100G>A/p.Gly34Arg) in C1QC in 1; homozygous missense alteration (c.1945G>C/p.Ala649Pro) in C1S in 1 (novel variant); and homozygous frameshift alteration (c.289_290delAC/p.Thr97Ilefs*2) in DNASE1L3 in 1 patient. Further, in 1 patient, we determined a strong candidate variant in HDAC7 (histone decetylase 7).Conclusion.Five patients had homozygous alterations in genes coding early complement proteins. This may lead to decreased clearance of apoptotic bodies. One patient had DNASE1L3 variant, which functions in the clearance of self-antigens. In 1 patient, we determined a novel gene that may be important in SLE pathogenesis. We suggest that monogenic causes/associations should be sought in early-onset and/or familial SLE.
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Complement and Immunoglobulin Biology Leading to Clinical Translation. Hematology 2018. [DOI: 10.1016/b978-0-323-35762-3.00024-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Early Complement Component Deficiency in a Single-Centre Cohort of Pediatric Onset Lupus. J Clin Immunol 2015; 35:777-85. [PMID: 26563161 DOI: 10.1007/s10875-015-0212-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/05/2015] [Indexed: 11/26/2022]
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Beurskens FJ, van Schaarenburg RA, Trouw LA. C1q, antibodies and anti-C1q autoantibodies. Mol Immunol 2015; 68:6-13. [PMID: 26032012 DOI: 10.1016/j.molimm.2015.05.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/04/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022]
Abstract
The complement system has long been known for its role in combating infections. More recently the complement system is becoming increasingly appreciated for its role in processes that range from waste transport, immune tolerance and shaping of the adaptive immune response. Antibodies represent the humoral part of the adaptive immune response and the complement system interacts with antibodies in several ways. Activated complement fragments impact on the production of antibodies, the complement system gets activated by antibodies and complement proteins can be the target of (auto)antibodies. In this review, written to celebrate the contributions of Prof. Dr. M.R. Daha to the field of immunology and especially complement, we will focus on C1q and its various interactions with antibodies. We will specifically focus on the mechanisms by which C1q will interact with monomeric IgG versus polymerized IgG and fluid-phase IgM versus solid-phase IgM. In addition in this review we will discuss in detail how C1q itself is targeted by autoantibodies and how these autoantibodies are currently considered to play a role in human disease.
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Affiliation(s)
| | | | - Leendert A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
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Liphaus BL, Umetsu N, Jesus AA, Bando SY, Silva CA, Carneiro-Sampaio M. Molecular characterization of the complement C1q, C2 and C4 genes in Brazilian patients with juvenile systemic lupus erythematosus. Clinics (Sao Paulo) 2015; 70:220-7. [PMID: 26017655 PMCID: PMC4449463 DOI: 10.6061/clinics/2015(03)12] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 01/05/2015] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE To perform a molecular characterization of the C1q, C2 and C4 genes in patients with juvenile systemic lupus erythematosus. METHODS Patient 1 (P1) had undetectable C1q, patient 2 (P2) and patient 3 (P3) had decreased C2 and patient 4 (P4) had decreased C4 levels. All exons and non-coding regions of the C1q and C2 genes were sequenced. Mononuclear cells were cultured and stimulated with interferon gamma to evaluate C1q, C2 and C4 mRNA expression by quantitative real-time polymerase chain reaction. RESULTS C1q sequencing revealed heterozygous silent mutations in the A (c.276 A>G Gly) and C (c.126 C>T Pro) chains, as well as a homozygous single-base change in the 3' non-coding region of the B chain (c*78 A>G). C1qA mRNA expression without interferon was decreased compared with that of healthy controls (p<0.05) and was decreased after stimulation compared with that of non-treated cells. C1qB mRNA expression was decreased compared with that of controls and did not change with stimulation. C1qC mRNA expression was increased compared with that of controls and was even higher after stimulation. P2 and P3 had Type I C2 deficiency (heterozygous 28 bp deletion at exon 6). The C2 mRNA expression in P3 was 23 times lower compared with that of controls and did not change after stimulation. The C4B mRNA expression of P4 was decreased compared with that of controls and increased after stimulation. CONCLUSIONS Silent mutations and single-base changes in the 3' non-coding regions may modify mRNA transcription and C1q production. Type I C2 deficiency should be evaluated in JSLE patients with decreased C2 serum levels. Further studies are needed to clarify the role of decreased C4B mRNA expression in JSLE pathogenesis.
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Affiliation(s)
- Bernadete L Liphaus
- Laboratório de Investigação Médica 36, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Natalia Umetsu
- Laboratório de Investigação Médica 36, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Adriana A Jesus
- Unidade de Reumatologia, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Silvia Y Bando
- Laboratório de Investigação Médica 36, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Clovis A Silva
- Unidade de Reumatologia, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Magda Carneiro-Sampaio
- Laboratório de Investigação Médica 36, Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
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van Schaarenburg RA, Daha NA, Schonkeren JJM, Nivine Levarht EW, van Gijlswijk-Janssen DJ, Kurreeman FAS, Roos A, van Kooten C, Koelman CA, Ernst-Kruis MR, Toes REM, Huizinga TWJ, Lankester AC, Trouw LA. Identification of a novel non-coding mutation in C1qB in a Dutch child with C1q deficiency associated with recurrent infections. Immunobiology 2014; 220:422-7. [PMID: 25454803 DOI: 10.1016/j.imbio.2014.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 10/06/2014] [Accepted: 10/12/2014] [Indexed: 11/18/2022]
Abstract
INTRODUCTION C1q deficiency is a rare genetic disorder that is strongly associated with development of systemic lupus erythematosus (SLE). Several mutations in the coding regions of the C1q genes have been described that result in stop-codons or other genetic abnormalities ultimately leading to C1q deficiency. Here we report on a Dutch boy suffering from recurrent infections with a complete C1q deficiency, without any SLE symptoms. METHODS The presence of C1q in serum was assessed using ELISA and hemolytic assay. By western blot we examined the different C1q chains in cell lysates. We identified the mutation using deep-sequencing. By qPCR we studied the mRNA expression of C1qA, C1qB and C1qC in the PBMCs of the patient. RESULTS Deep-sequencing revealed a homozygous mutation in the non-coding region of C1qB in the patient, whereas both parents were heterozygous. The mutation is located two nucleotides before the splice site of the second exon. In-silico analyses predict a complete abrogation of this natural splice site. Analyses of in vitro cultured cells from the patient revealed a lack of production of C1q and intracellular absence of C1qB in the presence of C1qA and C1qC peptides. Quantitative PCR analysis revealed total absence of C1qB mRNA, a reduced level of C1qA mRNA and normal levels of C1qC mRNA. CONCLUSION In this study we report a new mutation in the non-coding region of C1qB that is associated with C1q deficiency.
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Affiliation(s)
| | - Nina A Daha
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Joris J M Schonkeren
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - E W Nivine Levarht
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Fina A S Kurreeman
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Anja Roos
- Department of Clinical Chemistry, Leiden University Medical Center, Leiden, The Netherlands; Department of Medical Microbiology and Immunology, St Antonius Hospital, Nieuwegein, The Netherlands
| | - Cees van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Rene E M Toes
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tom W J Huizinga
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Arjan C Lankester
- Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Leendert A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
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Genetics of SLE: functional relevance for monocytes/macrophages in disease. Clin Dev Immunol 2012; 2012:582352. [PMID: 23227085 PMCID: PMC3511832 DOI: 10.1155/2012/582352] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 08/24/2012] [Accepted: 09/25/2012] [Indexed: 01/13/2023]
Abstract
Genetic studies in the last 5 years have greatly facilitated our understanding of how the dysregulation of diverse components of the innate immune system contributes to pathophysiology of SLE. A role for macrophages in the pathogenesis of SLE was first proposed as early as the 1980s following the discovery that SLE macrophages were defective in their ability to clear apoptotic cell debris, thus prolonging exposure of potential autoantigens to the adaptive immune response. More recently, there is an emerging appreciation of the contribution both monocytes and macrophages play in orchestrating immune responses with perturbations in their activation or regulation leading to immune dysregulation. This paper will focus on understanding the relevance of genes identified as being associated with innate immune function of monocytes and macrophages and development of SLE, particularly with respect to their role in (1) immune complex (IC) recognition and clearance, (2) nucleic acid recognition via toll-like receptors (TLRs) and downstream signalling, and (3) interferon signalling. Particular attention will be paid to the functional consequences these genetic associations have for disease susceptibility or pathogenesis.
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Foltyn Zadura A, Zipfel PF, Bokarewa MI, Sturfelt G, Jönsen A, Nilsson SC, Hillarp A, Saxne T, Trouw LA, Blom AM. Factor H autoantibodies and deletion of Complement Factor H-Related protein-1 in rheumatic diseases in comparison to atypical hemolytic uremic syndrome. Arthritis Res Ther 2012; 14:R185. [PMID: 22894814 PMCID: PMC3580581 DOI: 10.1186/ar4016] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 08/15/2012] [Indexed: 12/18/2022] Open
Abstract
Introduction Complement activation is involved in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and atypical hemolytic uremic syndrome (aHUS). Autoantibodies to complement inhibitor factor H (FH), particularly in association with deletions of the gene coding for FH-related protein 1 (CFHR1), are associated with aHUS. Methods Autoantibodies against FH, factor I (FI) and C4b-binding protein (C4BP) were measured by ELISA, while CFHR1 homozygous deletion was determined with Western blotting of sera. Epitopes for FH autoantibodies were mapped using recombinant fragments of FH. Results FH autoantibodies were detected in SLE (6.7%, n = 60, RA patients (16.5%, n = 97 in the Swedish cohort and 9.2%, n = 217 in the Dutch cohort) and thrombosis patients positive for the lupus anticoagulants (LA+) test (9.4%, n = 64) compared with aHUS patients (11.7%, n = 103). In the control groups (n = 354), an average of 4% of individuals were positive for FH autoantibodies. The frequencies observed in both RA cohorts and LA+ patients were statistically significantly higher than in controls. We also found that an average of 15.2% of the FH-autoantibody positive individuals in all studied disease groups had homozygous deficiency of CFHR1 compared with 3.8% of the FH autoantibody negative patients. The levels of FH autoantibodies varied in individual patients over time. FH autoantibodies found in LA+, SLE and RA were directed against several epitopes across FH in contrast to those found in aHUS, which bound mainly to the C-terminus. Autoantibodies against FI and C4BP were detected in some patients and controls but they were not associated with any of the diseases analyzed in this study. Conclusions Autoantibodies against FH are not specific for aHUS but are present at a significant frequency in rheumatic diseases where they could be involved in pathophysiological mechanisms.
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Lumry WR, Li HH, Levy RJ, Potter PC, Farkas H, Moldovan D, Riedl M, Li H, Craig T, Bloom BJ, Reshef A. Randomized placebo-controlled trial of the bradykinin B₂ receptor antagonist icatibant for the treatment of acute attacks of hereditary angioedema: the FAST-3 trial. Ann Allergy Asthma Immunol 2011; 107:529-37. [PMID: 22123383 DOI: 10.1016/j.anai.2011.08.015] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/09/2011] [Accepted: 08/30/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND The For Angioedema Subcutaneous Treatment (FAST)-3 study was a phase III, randomized, double-blind, placebo-controlled study of icatibant (bradykinin B(2) receptor antagonist) in subjects with hereditary angioedema (HAE) resulting from C1-INH deficiency or dysfunction (type I/II). OBJECTIVE To investigate icatibant efficacy and safety in subjects with acute HAE attacks. METHODS Subjects with moderate to very severe cutaneous or abdominal symptoms received icatibant (n = 43) or placebo (n = 45). Five subjects with laryngeal (mild-to-moderate) first attacks received icatibant (n = 3) or placebo (n = 2), and 5 subjects with severe laryngeal first attacks received open-label icatibant. RESULTS Cutaneous or abdominal attacks: icatibant significantly reduced median times (vs placebo) to 50% or more reduction in symptom severity (2.0 vs 19.8 hours; P < .001, primary endpoint), onset of primary symptom relief (1.5 vs 18.5 hours; P < .001, key secondary endpoint), or almost complete symptom relief (8.0 vs 36.0 hours; P = .012) and provided a shorter time to initial symptom relief (0.8 vs 3.5 hours; P < .001). For laryngeal attacks, median time to 50% or more reduction in symptom severity was 2.5 hours (icatibant) and 3.2 hours (placebo). No icatibant-treated subject required rescue medication before symptom relief occurred. The incidence of adverse events (AEs) was similar in icatibant- and placebo-treated subjects (41% and 52%, respectively). All icatibant-treated subjects experienced injection site reactions, but none reported clinically relevant changes in safety parameters or serious AEs. CONCLUSIONS FAST-3 demonstrated that icatibant was effective and generally well tolerated in subjects with acute HAE attacks. TRIAL REGISTRATION Clinicaltrials.gov Identifier: NCT00912093.
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Affiliation(s)
- William R Lumry
- Allergy and Asthma Research Associates Research Center, Dallas, Texas 75081, USA.
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Genetic risk factors of systemic lupus erythematosus in the Malaysian population: a minireview. Clin Dev Immunol 2011; 2012:963730. [PMID: 21941582 PMCID: PMC3176625 DOI: 10.1155/2012/963730] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 07/20/2011] [Indexed: 12/27/2022]
Abstract
SLE is an autoimmune disease that is not uncommon in Malaysia. In contrast to Malays and Indians, the Chinese seem to be most affected. SLE is characterized by deficiency of body's immune response that leads to production of autoantibodies and failure of immune complex clearance. This minireview attempts to summarize the association of several candidate genes with risk for SLE in the Malaysian population and discuss the genetic heterogeneity that exists locally in Asians and in comparison with SLE in Caucasians. Several groups of researchers have been actively investigating genes that are associated with SLE susceptibility in the Malaysian population by screening possible reported candidate genes across the SLE patients and healthy controls. These candidate genes include MHC genes and genes encoding complement components, TNF, FcγR, T-cell receptors, and interleukins. However, most of the polymorphisms investigated in these genes did not show significant associations with susceptibility to SLE in the Malaysian scenario, except for those occurring in MHC genes and genes coding for TNF-α, IL-1β, IL-1RN, and IL-6.
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Molecular basis of hereditary C1q deficiency--revisited: identification of several novel disease-causing mutations. Genes Immun 2011; 12:626-34. [PMID: 21654842 DOI: 10.1038/gene.2011.39] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
C1q is the central pattern-recognition molecule in the classical pathway of the complement system and is known to have a key role in the crossroads between adaptive and innate immunity. Hereditary C1q deficiency is a rare genetic condition strongly associated with systemic lupus erythematosus and increased susceptibility to bacterial infections. However, the clinical symptoms may vary. For long, the molecular basis of C1q deficiency was ascribed to only six different mutations. In the present report, we describe five new patients with C1q deficiency, present the 12 causative mutations described till now and review the clinical spectrum of symptoms found in patients with C1q deficiency. With the results presented here, confirmed C1q deficiency is reported in 64 patients from at least 38 families.
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Skattum L, van Deuren M, van der Poll T, Truedsson L. Complement deficiency states and associated infections. Mol Immunol 2011; 48:1643-55. [PMID: 21624663 DOI: 10.1016/j.molimm.2011.05.001] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 04/29/2011] [Accepted: 05/02/2011] [Indexed: 10/18/2022]
Abstract
A major function of the immune system is to protect the host from microbial infections. The complement system plays important roles in both the innate and the adaptive immune defense and also acts as a bridge between these arms of immunity. This is obvious from complement deficiencies which in varying degree, depending on which factor is missing, are associated with increased infection susceptibility and also increased risk for other, mainly autoimmune diseases. Genetically determined deficiencies are described for almost all complement proteins but the consequences show a wide variation. Here the genetic defects and molecular abnormalities in complement deficient persons, related clinically relevant infections and the options for prevention and therapy are reviewed. The roles of complement in host defense against common infections are also discussed.
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Affiliation(s)
- Lillemor Skattum
- Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
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Tsirogianni A, Pipi E, Soufleros K. Relevance of anti-C1q autoantibodies to lupus nephritis. Ann N Y Acad Sci 2009; 1173:243-51. [PMID: 19758158 DOI: 10.1111/j.1749-6632.2009.04750.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The first component of the classical pathway of the complement system (C1q) is considered to have a crucial role in the clearance of immune complexes (ICs) as well as in the removal of waste material originating from apoptotic cells. A prolonged exposure of C1q epitopes to the immune system could eventually lead to an autoimmune response against itself. Although autoantibodies against C1q are found in several diseases, their clinical interest originates from their strong association to active lupus nephritis (LN). Several studies indicate that anti-C1q autoantibodies could serve as a reliable serologic marker in the assessment of LN activity compared to other immunological tests. Additionally, it was suggested that anti-C1q autoantibodies could play a role in LN pathogenesis. Their potential pathogenic actions likely depend on genetic background, titers, Ig classes and subclasses, and specific epitopes of anti-C1q autoantibodies as well as C1q availability and allocation. It is still unclear which different types of anti-C1q autoantibodies dominate in each case and if their upregulation is pathogenic, an epiphenomenon of aberrant tissue damage, or compensatory to an uncontrolled immune response.
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Affiliation(s)
- Alexandra Tsirogianni
- Department of Immunology-Histocompatibility, Evangelismos General Hospital, Athens, Greece.
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Racila E, Link BK, Weng WK, Witzig TE, Ansell S, Maurer MJ, Huang J, Dahle C, Halwani A, Levy R, Weiner GJ. A polymorphism in the complement component C1qA correlates with prolonged response following rituximab therapy of follicular lymphoma. Clin Cancer Res 2008; 14:6697-703. [PMID: 18927313 DOI: 10.1158/1078-0432.ccr-08-0745] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Complement may play a role in the clinical response to rituximab and other monoclonal antibody-based therapies of cancer. The purpose of this study was to explore the relationship between the C1qA([276]) polymorphism and the clinical response to rituximab in patients with follicular lymphoma. EXPERIMENTAL DESIGN Genotyping for C1qA([276A/G]) was done in 133 subjects with follicular lymphoma treated with single-agent rituximab, and correlation with clinical response was done using Cox regression analysis. RESULTS Prolonged remission was observed among subjects that responded clinically to rituximab therapy and were carriers of the A allele compared with homozygous G subjects. Homozygous G subjects had a time to progression of 282 days, whereas A-allele carriers had a time to progression of 708 days [hazard ratio, (HR), 2.5; 95% confidence interval (95% CI), 2.0-3.1; P = 0.02]. Among subjects who achieved complete remission, homozygous G subjects had a time to progression of 250 days, whereas A-allele carriers had a time to progression of 1,118 days (HR, 4.5; 95% CI, 4.1-4.8, P = 0.04). The difference persisted after controlling for CD32 and CD16 polymorphisms. In patients who responded to rituximab used as first-line agent, a linear trend was observed among the C1qA([276]) genotypes, with homozygous A subjects achieving complete response at a higher rate compared with heterozygous or homozygous G subjects. CONCLUSIONS Our findings indicate that polymorphisms in the C1qA gene may affect the clinical response and duration of response to rituximab therapy of follicular lymphoma. These results could have direct implications on designing antibodies with improved efficiency and enhance our understanding of the role of complement in monoclonal antibody therapy.
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Affiliation(s)
- Emilian Racila
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA.
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Pickering MC, Macor P, Fish J, Durigutto P, Bossi F, Petry F, Botto M, Tedesco F. Complement C1q and C8 deficiency in an individual with recurrent bacterial meningitis and adult-onset systemic lupus erythematosus-like illness. Rheumatology (Oxford) 2008; 47:1588-9. [DOI: 10.1093/rheumatology/ken289] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Chew CH, Chua KH, Lian LH, Puah SM, Tan SY. PCR-RFLP genotyping of C1q mutations and single nucleotide polymorphisms in Malaysian patients with systemic lupus erythematosus. Hum Biol 2008; 80:83-93. [PMID: 18505047 DOI: 10.3378/1534-6617(2008)80[83:pgocma]2.0.co;2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Five types of known mutations within the C1q gene [located at C1qA-Gln186 (C >T), C1qB-Gly15 (G >A), C1qB-Arg150 (C >T), C1qC-Gly6 (G >A), and C1qC-Arg41 (C >T)] and two SNPs located at C1qA-Gly70 (G/A) and C1qC-Pro14 (T/C) were screened in a multiracial Malaysian population. One hundred thirty patients with systemic lupus erythematosus (SLE) and 130 matched healthy control subjects were genotyped using PCR-RFLP methods. We found no occurrence of the five types of mutations in either the homozygous or heterozygous form among the 260 samples studied. Statistical analysis also revealed that there were no significant associations observed in the genotype distributions and allele frequencies among the patients with SLE and healthy control subjects with both C1qA-Gly70 (G/A) and C1qC-Pro14 (T/C) SNPs. Overall, C1q deficiency was not proven as a primary causative genetic predisposition factor for SLE in the Malaysian population.
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Affiliation(s)
- C H Chew
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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18
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Vogt B, Führnrohr B, Müller R, Sheriff A. CRP and the disposal of dying cells: consequences for systemic lupus erythematosus and rheumatoid arthritis. Autoimmunity 2007; 40:295-8. [PMID: 17516213 DOI: 10.1080/08916930701358925] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
C reactive protein (CRP) levels directly correlate with the disease activity of many inflammatory diseases, e.g. sepsis, infection, and various autoimmunopathies such as rheumatoid arthritis (RA). In contrast, insufficient CRP levels are implicated in the development of systemic lupus erythematosus (SLE). This article reports on the level-depended effects of CRP in various diseases. In detail we show that increased and decreased levels of CRP, as demonstrated in patients with RA and SLE, respectively can contribute to disease progression.
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Affiliation(s)
- Birgit Vogt
- Department of Biotechnology, University of Applied Science, Berlin, Germany
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19
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C1q deficiency in an Inuit family: Identification of a new class of C1q disease-causing mutations. Clin Immunol 2007; 124:33-40. [DOI: 10.1016/j.clim.2007.03.547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 03/26/2007] [Accepted: 03/28/2007] [Indexed: 11/22/2022]
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20
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Petry F, Loos M. Common silent mutations in all types of hereditary complement C1q deficiencies. Immunogenetics 2005; 57:566-71. [PMID: 16086173 DOI: 10.1007/s00251-005-0023-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 07/08/2005] [Indexed: 10/25/2022]
Abstract
Hereditary complete deficiency of complement component C1q is a rare genetic disorder that is associated with severe recurrent infections and a high prevalence of lupus-erythematosus-like symptoms. In the past, several single nucleotide polymorphisms have been identified in all three genes coding for the C1q A, B, and C chains. These point mutations which either lead to termination codons, frameshift, or amino acid exchanges were thought to be responsible for these defects as no other nonsense or missense mutations were found. As a result of the aberrations, either a nonfunctional C1q antigen is present or no C1q protein is detectable in the patients' sera. Screening 46 individuals from seven families with different forms of C1q deficiencies identified a homologous silent mutation at position Gly70 (GGG > GGA) of the C1q A gene of all 11 C1q-deficient patients. A high number of family members that were heterozygous for the coding mutations carried the silent mutation in the homozygous (18%) or heterozygous (36%) state. In addition to the Gly70 mutation in the A gene, another homozygous silent mutation (C gene at position Pro14, CCT >CCC) was detected in all C1q-deficient patients.
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Affiliation(s)
- Franz Petry
- Institute of Medical Microbiology and Hygiene, Johannes Gutenberg-University Mainz, Germany.
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21
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Cunninghame Graham DS, Vyse TJ. The candidate gene approach: have murine models informed the study of human SLE? Clin Exp Immunol 2004; 137:1-7. [PMID: 15196236 PMCID: PMC1809082 DOI: 10.1111/j.1365-2249.2004.02525.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Genome wide linkage studies in human SLE have identified seven highly significant loci linked to SLE, and more than 20 other loci showing suggestive linkage to disease. However, pin-pointing the susceptibility alleles in candidate genes within these linkage regions is challenging, due the genetic heterogeneity, racial differences and environmental influences on disease aetiology. Utilization of murine models of spontaneous lupus nephritis provide a complementary approach, which may then identify candidate genes for analysis in human cases. This review highlights the utility of cross-species approach to identify and characterize the effect of given candidate genes in lupus. The examples described in this review demonstrate the importance of bringing together both genetic and functional information in human and mouse studies.
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Affiliation(s)
- D S Cunninghame Graham
- Rheumatology Section, Imperial College Faculty of Medicine, Hammersmith Hospital, London, UK.
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22
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Sheriff A, Gaipl US, Voll RE, Kalden JR, Herrmann M. Apoptosis and systemic lupus erythematosus. Rheum Dis Clin North Am 2004; 30:505-27, viii-ix. [PMID: 15261339 DOI: 10.1016/j.rdc.2004.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Reduced clearance of dying cells by macrophages or increased apoptosis provokes accumulation of cellular fragments in various tissues. This process seems to induce the uptake of autoantigens from apoptotic nuclei or chromatin by dendritic cells (DCs). Then, the DCs present altered self-epitopes to naive T cells. Thus, autoreactive T cells are activated accidentally and may now provide T-cell help for B cells that present peptides processed from secondary necrotic/late apoptotic prey. Impaired phagocytic removal of early apoptotic cells may cause accumulation of secondary necrotic cells and debris in the germinal centers of secondary lymph organs. The latter bind complement and can, therefore, be trapped on the surfaces of follicular DCs (FDCs). B cells may get in contact with intracellular autoantigens that had been released during late stages of apoptotic cell death and are immobilized by FDCs. Consecutively, B cells that had, for example, gained specificity for nuclear auto-antigens during random somatic mutations can receive a short-term survival signal. After migration into the mantle zone, these autoreactive B cells may finally be activated by autoreactive CD4+ T helper cells. B cells then differentiate into memory or plasma cells. The plasma cells produce those pathogenic nuclear autoantibodies. Many defects are known with respect to the clearance of apoptotic cells and cell material, especially that of nuclear origin. Reflecting on the plethora of defects of clearance of apoptotic material already demonstrated in systemic lupus erythematosus, it is reasonable to argue that, for many patients, failure of clearance is at the heart of their disease.
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Affiliation(s)
- Ahmed Sheriff
- Institute for Clinical Immunology and Rheumatology, Medical Department III, University of Erlangen-Nüremberg, Glueckstrasse 4a, 91054 Erlangen, Germany
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23
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Wen L, Atkinson JP, Giclas PC. Clinical and laboratory evaluation of complement deficiency. J Allergy Clin Immunol 2004; 113:585-93; quiz 594. [PMID: 15100659 DOI: 10.1016/j.jaci.2004.02.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The complement system provides innate defense against microbial pathogens and is a "complement" to humoral (antibody-mediated) immunity. Consisting of plasma and membrane proteins, this proinflammatory system works in part by a cascade involving limited proteolysis whereby one component activates the next, resulting in a dramatic amplification. The overall goal is deposition of complement fragments on pathologic targets for the purposes of opsonization, lysis, and liberation of peptides that promote the inflammatory response. Deficiencies of complement components predispose to infections and autoimmune syndromes. Even though total deficiency of a complement component is rare, patients presenting with certain bacterial infections and autoimmune syndromes, especially SLE, have a much greater incidence of deficiency. This review will summarize the clinical manifestations and pathophysiology of congenital and acquired complement deficiency diseases. We will also present an algorithm for laboratory diagnosis of complement deficiency and discuss current and future therapeutic options.
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Affiliation(s)
- Leana Wen
- Washington University School of Medicine, St Louis, Missouri, USA
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24
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Castellano G, Woltman AM, Nauta AJ, Roos A, Trouw LA, Seelen MA, Schena FP, Daha MR, van Kooten C. Maturation of dendritic cells abrogates C1q production in vivo and in vitro. Blood 2004; 103:3813-20. [PMID: 14726389 DOI: 10.1182/blood-2003-09-3046] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells (DCs) and complement are essential components of the innate immune system. Immature DCs (immDCs) and mature DCs (mDCs) can migrate to lymphoid areas inducing, respectively, tolerance and immune responses. Primary deficiency of complement component C1q (C1q) leads to autoimmunity, suggesting a role in the maintenance of tolerance. In the present study, we investigated the production of C1q by immDCs, mDCs, and macrophages. We demonstrated that monocyte-derived and CD34(+)-derived interstitial DCs are a rich source of C1q. C1q produced by immDCs is functionally active in complement activation and binding to apoptotic cells. The production of C1q is completely down-regulated upon DC maturation in vitro. Moreover, we found that DC differentiation in the presence of interferon-alpha (IFN-alpha) accelerated DC maturation and strongly impaired overall C1q production. Finally, we demonstrated the presence, in significant numbers, of DC-SIGN(+)/C1q(+) cells in T-cell areas of tonsils, next to DC-LAMP(+) mDCs lacking C1q. We conclude from these results that immDC, a cell with tolerogenic properties, is a rich source of active C1q in vitro and in vivo, which is down-regulated on maturation. Therefore, immDCs may be considered an additional source of C1q in humans.
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Affiliation(s)
- Giuseppe Castellano
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
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25
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Abstract
Genetic deficiencies of nearly all of the 30 complement system proteins have been recognized clinically. In many instances, the molecular basis for the deficiency has been elucidated. As a byproduct of these studies, we now have new insights into the pathophysiologic role of complement studies in several acquired diseases. New targets for drug development are among the practical outcomes of work on complement genetics.
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Affiliation(s)
- Harvey R Colten
- Translational Research in the Faculties of Health Sciences and Medicine, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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26
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Miura-Shimura Y, Nakamura K, Ohtsuji M, Tomita H, Jiang Y, Abe M, Zhang D, Hamano Y, Tsuda H, Hashimoto H, Nishimura H, Taki S, Shirai T, Hirose S. C1q regulatory region polymorphism down-regulating murine c1q protein levels with linkage to lupus nephritis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:1334-9. [PMID: 12133956 DOI: 10.4049/jimmunol.169.3.1334] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Much of the pathology of systemic lupus erythematosus (SLE) is caused by deposition of immune complexes (ICs) into various tissues, including renal glomeruli. Because clearance of ICs depends largely on early complement component C1q, homozygous C1q deficiency is a strong genetic risk factor in SLE, although it is rare in SLE patients overall. In this work we addressed the issue of whether genetic polymorphisms affecting C1q levels may predispose to SLE, using the (NZB x NZW)F(1) model. C1q genes are composed of three genes, C1qa, C1qc, and C1qb, arranged in this order, and each gene consists of two exons separated by one intron. Sequence analysis of the C1q gene in New Zealand Black (NZB), New Zealand White (NZW), and BALB/c mice showed no polymorphisms in exons and introns of three genes. However, Southern blot analysis revealed unique insertion polymorphism of a total of approximately 3.5 kb in the C1qa upstream region of NZB mice. C1q levels in sera and culture supernatants of LPS-stimulated peritoneal macrophages and C1q messages in spleen cells were all lower in disease-free young NZB and (NZB x NZW)F(1) mice than in age-matched non-autoimmune NZW and BALB/c mice. Quantitative trait loci analysis using (NZB x NZW)F(1) x NZW backcrosses showed that NZB microsatellites in the vicinity of the C1q allele on chromosome 4 were significantly linked to low serum C1q levels and the development of nephritis. These data imply that not only C1q deficiency but also regulatory region polymorphisms down-regulating C1q levels may confer the risk for lupus nephritis by reducing IC clearance and thus promoting IC deposition in glomeruli.
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Affiliation(s)
- Yuko Miura-Shimura
- Department of Pathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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27
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Ogden CA, deCathelineau A, Hoffmann PR, Bratton D, Ghebrehiwet B, Fadok VA, Henson PM. C1q and mannose binding lectin engagement of cell surface calreticulin and CD91 initiates macropinocytosis and uptake of apoptotic cells. THE JOURNAL OF EXPERIMENTAL MEDICINE 2001. [PMID: 11560994 DOI: 10.1084/jem194.6.781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Removal of apoptotic cells is essential for maintenance of tissue homeostasis, organogenesis, remodeling, development, and maintenance of the immune system, protection against neoplasia, and resolution of inflammation. The mechanisms of this removal involve recognition of the apoptotic cell surface and initiation of phagocytic uptake into a variety of cell types. Here we provide evidence that C1q and mannose binding lectin (MBL), a member of the collectin family of proteins, bind to apoptotic cells and stimulate ingestion of these by ligation on the phagocyte surface of the multifunctional protein, calreticulin (also known as the cC1qR), which in turn is bound to the endocytic receptor protein CD91, also known as the alpha-2-macroglobulin receptor. Use of these proteins provides another example of apoptotic cell clearance mediated by pattern recognition molecules of the innate immune system. Ingestion of the apoptotic cells through calreticulin/CD91 stimulation is further shown to involve the process of macropinocytosis, implicated as a primitive and relatively nonselective uptake mechanism for C1q- and MBL-enhanced engulfment of whole, intact apoptotic cells, as well as cell debris and foreign organisms to which these molecules may bind.
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Affiliation(s)
- C A Ogden
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA
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28
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Ogden CA, deCathelineau A, Hoffmann PR, Bratton D, Ghebrehiwet B, Fadok VA, Henson PM. C1q and mannose binding lectin engagement of cell surface calreticulin and CD91 initiates macropinocytosis and uptake of apoptotic cells. J Exp Med 2001; 194:781-95. [PMID: 11560994 PMCID: PMC2195958 DOI: 10.1084/jem.194.6.781] [Citation(s) in RCA: 845] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2000] [Accepted: 07/23/2001] [Indexed: 12/11/2022] Open
Abstract
Removal of apoptotic cells is essential for maintenance of tissue homeostasis, organogenesis, remodeling, development, and maintenance of the immune system, protection against neoplasia, and resolution of inflammation. The mechanisms of this removal involve recognition of the apoptotic cell surface and initiation of phagocytic uptake into a variety of cell types. Here we provide evidence that C1q and mannose binding lectin (MBL), a member of the collectin family of proteins, bind to apoptotic cells and stimulate ingestion of these by ligation on the phagocyte surface of the multifunctional protein, calreticulin (also known as the cC1qR), which in turn is bound to the endocytic receptor protein CD91, also known as the alpha-2-macroglobulin receptor. Use of these proteins provides another example of apoptotic cell clearance mediated by pattern recognition molecules of the innate immune system. Ingestion of the apoptotic cells through calreticulin/CD91 stimulation is further shown to involve the process of macropinocytosis, implicated as a primitive and relatively nonselective uptake mechanism for C1q- and MBL-enhanced engulfment of whole, intact apoptotic cells, as well as cell debris and foreign organisms to which these molecules may bind.
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Affiliation(s)
- Carol Anne Ogden
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Aimee deCathelineau
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Peter R. Hoffmann
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Donna Bratton
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Berhane Ghebrehiwet
- Department of Medicine, Health Sciences Center, State University of New York, Stony Brook, Stony Brook, NY 11794
| | - Valerie A. Fadok
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
| | - Peter M. Henson
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
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29
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Herrmann M, Voll RE, Kalden JR. Etiopathogenesis of systemic lupus erythematosus. IMMUNOLOGY TODAY 2000; 21:424-6. [PMID: 10953093 DOI: 10.1016/s0167-5699(00)01675-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- M Herrmann
- Institute for Clinical Immunology and Rheumatology, Medical Department III, University Erlangen-Nuremberg, Kran-kenhausstrasse 12, 91054 Erlangen, Germany.
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30
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Abstract
We report a case of systemic lupus erythematosus associated with C1q deficiency. Our patient presented at the age of 6 years with cutaneous lupus. She later developed Raynaud's phenomenon, non-scarring alopecia, oral ulceration and grand mal seizures due to cerebral vasculitis. Complement C3 and C4 levels were consistently normal during flares of her lupus and haemolytic activity of her complement was absent, suggesting a deficiency of an early component of the complement cascade. No C1q could be detected.
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Affiliation(s)
- N M Stone
- Department of Dermatology, Department of Immunology, Oxford Radcliffe Hospital, Old Road, Headington, Oxford OX3 7LJ, U.K
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31
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Berkel AI, Birben E, Oner C, Oner R, Loos M, Petry F. Molecular, genetic and epidemiologic studies on selective complete C1q deficiency in Turkey. Immunobiology 2000; 201:347-55. [PMID: 10776791 DOI: 10.1016/s0171-2985(00)80089-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective complete C1q deficiencies (SCDC1q) of the complement component C1q are rare genetic disorders with high prevalence of lupus-erythematosus-like symptoms and recurrent infections. Among the 41 published cases from 23 families, 10 derive from 6 Turkish families. One particular mutation leading to a stop codon in the C1q A gene was first identified in members of a Gypsy family from the Slovac Republic. Later the same mutation has been found in all cases in four SCDC1q families from Turkey suggesting that one particular defective allele may be present in the populations of Southeastern Europe and Turkey. This study was undertaken to investigate the frequency of C-->T mutation in exon II of C1qA gene in Turkish population by using allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Among the 1544 patients from 15 pediatric departments and an additional 89 SLE patients of various ages no C1qA gene mutation was found. There were 43 heterozygous and 4 homozygous mutations in 161 family members or relatives investigated from the 4 families known with SCDC1q. Among the 223 inhabitants who were nonrelative to the 3 SCDC1q families living in the same village were screened for mutation and one heterozygous individual was observed. Although this mutant allele appears to be at a low prevalence in the population tested, individuals with recurrent infections or symptoms of lupus erythematosus-like syndrome should be tested for this mutation to rule out this type of C1q deficiency.
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Affiliation(s)
- A I Berkel
- Dept. of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
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32
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Hiepe F, Pfüller B, Wolbart K, Bruns A, Leinenbach HP, Hepper M, Schössler W, Otto V. C1q: a multifunctional ligand for a new immunoadsorption treatment. THERAPEUTIC APHERESIS : OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR APHERESIS AND THE JAPANESE SOCIETY FOR APHERESIS 1999; 3:246-51. [PMID: 10427623 DOI: 10.1111/j.1091-6660.1999.t01-2-.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
C1q is a highly conserved protein with multiple functions involved in innate and adaptive immunity. It plays an important role in the activation of the classical pathway of the complement system to mediate the scavenging of infectious agents, apoptotic products, and immune complexes by the mononuclear phagocyte system (MPS). Exhibiting this function, C1q is able to bind various molecules (complexed IgG, IgM, fibrinogen, fibronectin, lipopolysaccharides, DNA, C-reactive protein [CRP], and viral proteins). Moreover, the collagen-like region of C1q is a target of autoantibodies. Immune complexes and anti-C1q autoantibodies are known to be involved in the pathogenesis of autoimmune diseases. Therefore, C1q is a promising candidate to extract waste material from the circulation. Following the development of the C1q immunoadsorbent, 8 patients with systemic lupus erythematosus (SLE) were treated in a first clinical trial. These preliminary results indicate that C1q immunoadsorption is a safe, compatible, and effective treatment for these patients.
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Affiliation(s)
- F Hiepe
- Department of Internal Medicine (Rheumatology and Clinical Immunology), University Hospital Charité, Humboldt-University, Berlin, Germany.
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