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Tserga A, Saulnier-Blache JS, Palamaris K, Pouloudi D, Gakiopoulou H, Zoidakis J, Schanstra JP, Vlahou A, Makridakis M. Complement Cascade Proteins Correlate with Fibrosis and Inflammation in Early-Stage Type 1 Diabetic Kidney Disease in the Ins2Akita Mouse Model. Int J Mol Sci 2024; 25:1387. [PMID: 38338666 PMCID: PMC10855735 DOI: 10.3390/ijms25031387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 02/12/2024] Open
Abstract
Diabetic kidney disease (DKD) is characterized by histological changes including fibrosis and inflammation. Evidence supports that DKD is mediated by the innate immune system and more specifically by the complement system. Using Ins2Akita T1D diabetic mice, we studied the connection between the complement cascade, inflammation, and fibrosis in early DKD. Data were extracted from a previously published quantitative-mass-spectrometry-based proteomics analysis of kidney glomeruli of 2 (early DKD) and 4 months (moderately advanced DKD)-old Ins2Akita mice and their controls A Spearman rho correlation analysis of complement- versus inflammation- and fibrosis-related protein expression was performed. A cross-omics validation of the correlation analyses' results was performed using public-domain transcriptomics datasets (Nephroseq). Tissue sections from 43 patients with DKD were analyzed using immunofluorescence. Among the differentially expressed proteins, the complement cascade proteins C3, C4B, and IGHM were significantly increased in both early and later stages of DKD. Inflammation-related proteins were mainly upregulated in early DKD, and fibrotic proteins were induced in moderately advanced stages of DKD. The abundance of complement proteins with fibrosis- and inflammation-related proteins was mostly positively correlated in early stages of DKD. This was confirmed in seven additional human and mouse transcriptomics DKD datasets. Moreover, C3 and IGHM mRNA levels were found to be negatively correlated with the estimated glomerular filtration rate (range for C3 rs = -0.58 to -0.842 and range for IGHM rs = -0.6 to -0.74) in these datasets. Immunohistology of human kidney biopsies revealed that C3, C1q, and IGM proteins were induced in patients with DKD and were correlated with fibrosis and inflammation. Our study shows for the first time the potential activation of the complement cascade associated with inflammation-mediated kidney fibrosis in the Ins2Akita T1D mouse model. Our findings could provide new perspectives for the treatment of early DKD as well as support the use of Ins2Akita T1D in pre-clinical studies.
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Affiliation(s)
- Aggeliki Tserga
- Biomedical Research Foundation, Academy of Athens, Department of Biotechnology, Soranou Efessiou 4, 11527 Athens, Greece; (A.T.); (J.Z.); (A.V.)
| | - Jean Sébastien Saulnier-Blache
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR1297, Institute of Cardiovascular and Metabolic Disease, 31432 Toulouse, France; (J.S.S.-B.); (J.P.S.)
- Department of Biology, Université Toulouse III Paul-Sabatier, 31062 Toulouse, France
| | - Kostantinos Palamaris
- 1st Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 34400 Athens, Greece; (K.P.); (D.P.); (H.G.)
| | - Despoina Pouloudi
- 1st Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 34400 Athens, Greece; (K.P.); (D.P.); (H.G.)
| | - Harikleia Gakiopoulou
- 1st Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 34400 Athens, Greece; (K.P.); (D.P.); (H.G.)
| | - Jerome Zoidakis
- Biomedical Research Foundation, Academy of Athens, Department of Biotechnology, Soranou Efessiou 4, 11527 Athens, Greece; (A.T.); (J.Z.); (A.V.)
- Department of Biology, National and Kapodistrian University of Athens, 15701 Zografou, Greece
| | - Joost Peter Schanstra
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR1297, Institute of Cardiovascular and Metabolic Disease, 31432 Toulouse, France; (J.S.S.-B.); (J.P.S.)
- Department of Biology, Université Toulouse III Paul-Sabatier, 31062 Toulouse, France
| | - Antonia Vlahou
- Biomedical Research Foundation, Academy of Athens, Department of Biotechnology, Soranou Efessiou 4, 11527 Athens, Greece; (A.T.); (J.Z.); (A.V.)
| | - Manousos Makridakis
- Biomedical Research Foundation, Academy of Athens, Department of Biotechnology, Soranou Efessiou 4, 11527 Athens, Greece; (A.T.); (J.Z.); (A.V.)
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Koopman JJE, van Essen MF, Rennke HG, de Vries APJ, van Kooten C. Deposition of the Membrane Attack Complex in Healthy and Diseased Human Kidneys. Front Immunol 2021; 11:599974. [PMID: 33643288 PMCID: PMC7906018 DOI: 10.3389/fimmu.2020.599974] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.
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Affiliation(s)
- Jacob J E Koopman
- Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Mieke F van Essen
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Helmut G Rennke
- Division of Renal Pathology, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Aiko P J de Vries
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Cees van Kooten
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
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3
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Complement Activation in Progression of Chronic Kidney Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1165:423-441. [PMID: 31399977 DOI: 10.1007/978-981-13-8871-2_20] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chronic kidney disease (CKD) is a public health problem worldwide, with increasing incidence and prevalence. The mechanisms underlying the progression to end-stage renal disease (ESRD) is not fully understood. The complement system was traditionally regarded as an important part of innate immunity required for host protection against infection and for maintaining host hemostasis. However, compelling evidence from both clinical and experimental studies has strongly incriminated complement activation as a pivotal pathogenic mediator of the development of multiple renal diseases and progressive replacement of functioning nephrons by fibrosis. Both anaphylatoxins, i.e., C3a and C5a, and membrane attack complex (MAC) contribute to the damage that occurs during chronic renal progression through various mechanisms including direct proinflammatory and fibrogenic activity, chemotactic effect, activation of the renal renin-angiotensin system, and enhancement of T-cell immunity. Evolving understanding of the mechanisms of complement-mediated renal injury has led to the emergence of complement-targeting therapeutics. A variety of specific antibodies and inhibitors targeting complement components have shown efficacy in reducing disease in animal models. Moreover, building on these advances, targeting complement has gained encouraging success in treating patients with renal diseases such as atypical hemolytic uremic syndrome (aHUS). Nevertheless, it still requires a great deal of effort to develop inhibitors that can be applied to treat more patients effectively in routine clinical practice.
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van de Lest NA, Zandbergen M, Wolterbeek R, Kreutz R, Trouw LA, Dorresteijn EM, Bruijn JA, Bajema IM, Scharpfenecker M, Chua JS. Glomerular C4d deposition can precede the development of focal segmental glomerulosclerosis. Kidney Int 2019; 96:738-749. [PMID: 31327475 DOI: 10.1016/j.kint.2019.04.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/17/2019] [Accepted: 04/22/2019] [Indexed: 01/08/2023]
Abstract
Recent studies suggest that complement plays a role in the pathogenesis of focal segmental glomerulosclerosis (FSGS). Moreover, co-localization of IgM and C3 deposits with FSGS lesions has frequently been reported. Here, we investigated whether glomerular complement deposition precedes the development of FSGS and whether it represents local complement activation. Renal biopsies from 40 patients with primary FSGS, 84 patients with minimal change disease, and 10 healthy individuals were stained for C4d, C1q, and mannose-binding lectin. C4d deposits were also measured in renal allograft biopsies from 34 patients with native primary FSGS, 18 of whom subsequently developed recurrent FSGS. Lastly, we measured C4d deposits in the Munich Wistar Frömter rat model of FSGS. The prevalence of C4d-positive glomeruli was significantly higher among patients with FSGS (73%) compared to patients with minimal change disease (21%) and healthy individuals (10%). Moreover, segmental sclerosis was absent in 42% of C4d-positive glomeruli. Glomerular C1q was significantly more prevalent in FSGS compared to minimal change disease or healthy individuals, while mannose-binding lectin was infrequently observed. C4d deposition was significantly more prevalent in recurrent FSGS (72%) before the development of sclerotic lesions compared to control transplant samples (27%). Finally, at the onset of albuminuria but before the development of FSGS lesions, Munich Wistar Frömter rats had a significantly higher percentage of C4d-positive glomeruli (31%) compared to control rats (4%). Thus, glomerular C4d deposition can precede the development of FSGS, suggesting that complement activation may play a pathogenic role in the development of FSGS.
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Affiliation(s)
- Nina A van de Lest
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Malu Zandbergen
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ron Wolterbeek
- Medical Statistics, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, The Netherlands
| | - Reinhold Kreutz
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Klinische Pharmakologie und Toxikologie, Germany
| | - Leendert A Trouw
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Eiske M Dorresteijn
- Department of Pediatric Nephrology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Jan A Bruijn
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ingeborg M Bajema
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Jamie S Chua
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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Rizk DV, Maillard N, Julian BA, Knoppova B, Green TJ, Novak J, Wyatt RJ. The Emerging Role of Complement Proteins as a Target for Therapy of IgA Nephropathy. Front Immunol 2019; 10:504. [PMID: 30941137 PMCID: PMC6433978 DOI: 10.3389/fimmu.2019.00504] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/25/2019] [Indexed: 12/28/2022] Open
Abstract
IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and a common cause of end-stage renal disease. Evaluation of a kidney biopsy is necessary for diagnosis, with routine immunofluorescence microscopy revealing dominant or co-dominant IgA immunodeposits usually with complement C3 and sometimes IgG and/or IgM. IgA nephropathy reduces life expectancy by more than 10 years and leads to kidney failure in 20–40% of patients within 20 years of diagnosis. There is accumulating clinical, genetic, and biochemical evidence that complement plays an important role in the pathogenesis of IgA nephropathy. The presence of C3 differentiates the diagnosis of IgA nephropathy from the subclinical deposition of glomerular IgA. Markers for the activation of the alternative and mannan-binding lectin (MBL) pathways in renal-biopsy specimens are associated with disease activity and portend a worse renal outcome. Complement proteins in the circulation have also been evaluated in IgA nephropathy and found to be of prognostic value. Recently, genetic studies have identified IgA nephropathy-associated loci. Within these loci are genes encoding products involved in complement regulation and interaction with immune complexes. Put together, these data identify the complement cascade as a rational treatment target for this chronic kidney disease. Recent case reports on the successful use of humanized anti-C5 monoclonal antibody eculizumab are consistent with this hypothesis, but a better understanding of the role of complement in IgA nephropathy is needed to guide future therapeutic interventions.
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Affiliation(s)
- Dana V Rizk
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Nicolas Maillard
- Department of Nephrology, Dialysis, Transplantation, CHU de Saint-Etienne, GIMAP, EA3064, Université Jean Monnet, COMUE Université de Lyon, Rhône-Alpes, France
| | - Bruce A Julian
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Barbora Knoppova
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czechia
| | - Todd J Green
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Robert J Wyatt
- Department of Pediatrics, University of Tennessee Health Sciences Center, Memphis, TN, United States
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Wilson HR, Medjeral-Thomas NR, Gilmore AC, Trivedi P, Seyb K, Farzaneh-Far R, Gunnarsson I, Zickert A, Cairns TD, Lightstone L, Cook HT, Pickering MC. Glomerular membrane attack complex is not a reliable marker of ongoing C5 activation in lupus nephritis. Kidney Int 2019; 95:655-665. [PMID: 30655025 PMCID: PMC6389546 DOI: 10.1016/j.kint.2018.09.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 02/08/2023]
Abstract
Complement plays an important role in the pathogenesis of lupus nephritis (LN). With the emergence of therapeutic complement inhibition, there is a need to identify patients in whom complement-driven inflammation is a major cause of kidney injury in LN. Clinical and histopathological data were obtained retrospectively from 57 biopsies with class III, IV, and V LN. Biopsies were stained for complement components C9, C5b-9, C3c, and C3d and for the macrophage marker CD68. C9 and C5b-9 staining were highly correlated (r = 0.92 in the capillary wall). C5b-9 staining was detected in the mesangium and/or capillary wall of both active and chronic proliferative LN in all but one biopsy and in the capillary wall of class V LN in all biopsies. C5b-9 staining intensity in the tubular basement membrane correlated with markers of tubulointerstitial damage, and more intense capillary wall C5b-9 staining was significantly associated with nonresponse to conventional treatment. Glomerular C5b-9 staining intensity did not differ between active and chronic disease; in contrast, C3c and CD68 staining were associated with active disease. Evaluation of serial biopsies and comparison of staining in active and chronic LN demonstrated that C5b-9 staining persisted for months to years. These results suggest that C5b-9 staining is almost always present in LN, resolves slowly, and is not a reliable marker of ongoing glomerular C5 activation. This limits the utility of C5b-9 staining to identify patients who are most likely to benefit from C5 inhibition.
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Affiliation(s)
- Hannah R Wilson
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | | | - Alyssa C Gilmore
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - Pritesh Trivedi
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - Kathleen Seyb
- Ra Pharmaceuticals, Inc., Cambridge, Massachusetts, USA
| | | | - Iva Gunnarsson
- Division of Rheumatology, Department of Medicine, Karolinska Institutet and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Agneta Zickert
- Division of Rheumatology, Department of Medicine, Karolinska Institutet and Rheumatology, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas D Cairns
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - Liz Lightstone
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - H Terence Cook
- Centre for Inflammatory Disease, Imperial College London, London, UK.
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7
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Complement activation in patients with diabetic nephropathy. DIABETES & METABOLISM 2018; 45:248-253. [PMID: 29729954 DOI: 10.1016/j.diabet.2018.04.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/15/2018] [Accepted: 04/07/2018] [Indexed: 01/10/2023]
Abstract
AIM Emerging evidence has indicated a role of the complement system in the pathogenesis of diabetic nephropathy (DN), although the pathways of complement activation and their clinicopathological relevance in DN are as yet unclear. The present study aimed to investigate levels of various complement components in plasma and urine of DN patients, and their correlation with clinicopathological parameters. METHODS A total of 68 biopsy-proven DN patients with plasma samples were recruited, including 50 patients who also had urine samples available. Seven complement components (C1q, MBL, Bb, C4d, C3a, C5a, soluble C5b-9) were measured by enzyme-linked immunosorbent assay (Elisa), and any associations between their levels and clinicopathological parameters were then investigated. RESULTS In DN patients, plasma levels of C1q, MBL, Bb, C4d, C3a, C5a and sC5b-9 were significantly higher than in diabetes patients without renal involvement, as were also urinary levels except for C1q, which showed no significant differences between the two groups. Also, urinary levels of C3a and C5a were significantly correlated with serum creatinine, urinary protein and estimated glomerular filtration rate, whereas urinary sC5b-9 was significantly correlated with the latter two (and not serum creatinine). In addition, urinary levels of MBL, Bb and C4d were significantly correlated with urinary protein, while C3a, C4d and Bb significantly correlated with the classification of glomerular lesions in DN. CONCLUSION In DN patients, the complement system is activated and, of the three possible complement pathways, activation of the lectin and alternative pathways is associated with renal damage.
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Bus P, Chua JS, Klessens CQF, Zandbergen M, Wolterbeek R, van Kooten C, Trouw LA, Bruijn JA, Baelde HJ. Complement Activation in Patients With Diabetic Nephropathy. Kidney Int Rep 2017; 3:302-313. [PMID: 29725633 PMCID: PMC5932121 DOI: 10.1016/j.ekir.2017.10.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/09/2017] [Indexed: 12/13/2022] Open
Abstract
Introduction Complement activation plays a role in various organs in patients with diabetes. However, in diabetic nephropathy (DN), the role of complement activation is poorly understood. We examined the prevalence and clinical significance of complement deposits in the renal tissue of cases with type 1 and type 2 diabetes with and without DN. Methods We measured the prevalence of glomerular C4d, C1q, mannose-binding lectin (MBL), and C5b-9 deposits in 101 autopsied diabetic cases with DN, 59 autopsied diabetic cases without DN, and 41 autopsied cases without diabetes or kidney disease. The presence of complement deposits was scored by researchers who were blinded with respect to the clinical and histological data. Results C4d deposits were more prevalent in cases with DN than in cases without DN in both the glomeruli (46% vs. 26%) and the arterioles (28% vs. 12%). C1q deposits were also increased in the glomerular hili (77% vs. 55%) and arterioles (33% vs.14%), and were correlated with DN (P < 0.01). MBL deposits were only rarely observed. C5b-9 deposits were more prevalent in the cases with diabetes mellitus (DM) than in the cases without DM (69% vs. 32%; P < 0.001). Finally, glomerular C4d and C5b-9 deposits were correlated with the severity of DN (ρ = 0.341 and 0.259, respectively; P < 0.001). Conclusion Complement activation is correlated with both the presence and severity of DN, suggesting that the complement system is involved in the development of renal pathology in patients with diabetes and is a promising target for inhibiting and/or preventing DN in these patients.
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Affiliation(s)
- Pascal Bus
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jamie S Chua
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Céline Q F Klessens
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Malu Zandbergen
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ron Wolterbeek
- Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands
| | - Cees van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Leendert A Trouw
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Jan A Bruijn
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hans J Baelde
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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9
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Abstract
The development of type 1 and type 2 diabetes mellitus has a substantial negative impact on morbidity and mortality and is responsible for substantial individual and socioeconomic costs worldwide. One of the most serious consequences of diabetes mellitus is the development of diabetic angiopathy, which manifests clinically as microvascular and macrovascular complications. One microvascular complication, diabetic nephropathy, is the most common cause of end-stage renal disease in developed countries. Although several available therapeutic interventions can delay the onset and progression of diabetic nephropathy, morbidity associated with this disease remains high and new therapeutic approaches are needed. In addition, not all patients with diabetes mellitus will develop diabetic nephropathy and thus new biomarkers are needed to identify individuals who will develop this life-threatening disease. An increasing body of evidence points toward a role of the complement system in the pathogenesis of diabetic nephropathy. For example, circulating levels of mannose-binding lectin (MBL), a pattern recognition molecule of the innate immune system, have emerged as a robust biomarker for the development and progression of this disease, and evidence suggests that MBL, H-ficolin, complement component C3 and the membrane attack complex might contribute to renal injury in the hyperglycaemic mileu. New approaches to modulate the complement system might lead to the development of new agents to prevent or slow the progression of diabetic nephropathy.
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Affiliation(s)
- Allan Flyvbjerg
- Steno Diabetes Center Copenhagen, Capital Region of Denmark, Niels Steensens Vej 2, DK-2820 Gentofte, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
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10
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Rother RP, Mojcik CF, McCroskery EW. Inhibition of terminal complement: a novel therapeutic approach for the treatment of systemic lupus erythematosus. Lupus 2016; 13:328-34. [PMID: 15230287 DOI: 10.1191/0961203303lu1021oa] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The importance of the complement system in the pathophysiology of systemic lupus erythematosus (SLE) is clear although individual complement components play very different roles in the disease process. Early complement proteins are critical in the clearance of immune complexes and apoptotic bodies, and their absencepredisposesindividualsto SLE. Conversely, activationof terminalcomplement is associated with exacerbations of disease and damage to tissues and organs, particularly in lupus nephritis. Monoclonal antibodies that specifically inhibit terminal complement activation while preserving the critical functions of the early complement cascade have now been developed. These antibodies target the C5 complement protein, blocking its cleavage and the subsequent generation of potent proinflammatory molecules. Anti-C5 therapeutics have recently been investigated in an animal model of SLE and in a Phase I single dose study in humans. The results of these studiesand the multiple roles of complement in SLE are discussed.
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Affiliation(s)
- R P Rother
- Alexion Pharmaceuticals Inc., Chesire, CT 06410, USA
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11
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Rangan GK. C5b-9 does not mediate tubulointerstitial injury in experimental acute glomerular disease characterized by selective proteinuria. World J Nephrol 2016; 5:288-299. [PMID: 27152265 PMCID: PMC4848152 DOI: 10.5527/wjn.v5.i3.288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/14/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine whether complement membrane attack complex (C5b-9) has a pathogenic role in tubulointerstitial injury in a renal disease model characterized by acute highly selective proteinuria.
METHODS: Protein-overload nephropathy (PON) was induced in adult female Piebald-Viral-Glaxo rats with or without complement C6 deficiency (C6- and C6+) by daily intraperitoneal injections of bovine serum albumin (BSA, 2 g/d), and examined on days 2, 4 and 8.
RESULTS: Groups with PON developed equivalent levels of heavy proteinuria within 24 h of BSA injection. In C6+ rats with PON, the tubulointerstitial expression of C5b-9 was increased and localized predominantly to the basolateral surface of tubular epithelial cells (TECs), whereas it was undetectable in C6- animals. TEC proliferation (as assessed by the number of BrdU+ cells) increased by more than 50-fold in PON, peaking on day 2 and declining on days 4 to 8. There was a trend for a reduction in the number of BrdU+ TECs on day 4 in the C6- PON group (P = 0.10 compared to C6+) but not at any other time-point. Kidney enlargement, TEC apoptosis (TUNEL+ cells) and markers of tubular injury (tubule dilatation, loss of TEC height, protein cast formation) were not altered by C6 deficiency in PON. Interstitial monocyte (ED-1+ cell) accumulation was partially reduced in C6- animals with PON on day 4 (P = 0.01) but there was no change in myofibroblast accumulation.
CONCLUSION: These data suggest that C5b-9 does not mediate tubulointerstitial injury in acute glomerular diseases characterized by selective proteinuria.
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12
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Ghosh P, Sahoo R, Vaidya A, Chorev M, Halperin JA. Role of complement and complement regulatory proteins in the complications of diabetes. Endocr Rev 2015; 36:272-88. [PMID: 25859860 PMCID: PMC4446516 DOI: 10.1210/er.2014-1099] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
It is well established that the organ damage that complicates human diabetes is caused by prolonged hyperglycemia, but the cellular and molecular mechanisms by which high levels of glucose cause tissue damage in humans are still not fully understood. The prevalent hypothesis explaining the mechanisms that may underlie the pathogenesis of diabetes complications includes overproduction of reactive oxygen species, increased flux through the polyol pathway, overactivity of the hexosamine pathway causing intracellular formation of advanced glycation end products, and activation of protein kinase C isoforms. In addition, experimental and clinical evidence reported in past decades supports a strong link between the complement system, complement regulatory proteins, and the pathogenesis of diabetes complications. In this article, we summarize the body of evidence that supports a role for the complement system and complement regulatory proteins in the pathogenesis of diabetic vascular complications, with specific emphasis on the role of the membrane attack complex (MAC) and of CD59, an extracellular cell membrane-anchored inhibitor of MAC formation that is inactivated by nonenzymatic glycation. We discuss a pathogenic model of human diabetic complications in which a combination of CD59 inactivation by glycation and hyperglycemia-induced complement activation increases MAC deposition, activates pathways of intracellular signaling, and induces the release of proinflammatory, prothrombotic cytokines and growth factors. Combined, complement-dependent and complement-independent mechanisms induced by high glucose promote inflammation, proliferation, and thrombosis as characteristically seen in the target organs of diabetes complications.
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Affiliation(s)
- Pamela Ghosh
- Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Rupam Sahoo
- Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Anand Vaidya
- Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Michael Chorev
- Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Jose A Halperin
- Division of Hematology, Department of Medicine (P.G., R.S., M.C., J.A.H.), and Division of Endocrinology, Diabetes, and Hypertension (A.V.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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Urinary candidate biomarker discovery in a rat unilateral ureteral obstruction model. Sci Rep 2015; 5:9314. [PMID: 25791774 PMCID: PMC4366765 DOI: 10.1038/srep09314] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/26/2015] [Indexed: 12/12/2022] Open
Abstract
Urine has the potential to become a better source of biomarkers. Urinary proteins are affected by many factors; therefore, differentiating between the variables associated with any particular pathophysiological condition in clinical samples is challenging. To circumvent these problems, simpler systems, such as animal models, should be used to establish a direct relationship between disease progression and urine changes. In this study, a unilateral ureteral obstruction (UUO) model was used to observe tubular injury and the eventual development of renal fibrosis, as well as to identify differential urinary proteins in this process. Urine samples were collected from the residuary ureter linked to the kidney at 1 and 3 weeks after UUO. Five hundred proteins were identified and quantified by LC-MS/MS, out of which 7 and 19 significantly changed in the UUO 1- and 3-week groups, respectively, compared with the sham-operation group. Validation by western blot showed increased levels of Alpha-actinin-1 and Moesin in the UUO 1-week group, indicating that they may serve as candidate biomarkers of renal tubular injury, and significantly increased levels of Vimentin, Annexin A1 and Clusterin in the UUO 3-week group, indicating that they may serve as candidate biomarkers of interstitial fibrosis.
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Da'dara AA, Krautz-Peterson G. New insights into the reaction of Schistosoma mansoni cercaria to the human complement system. Parasitol Res 2014; 113:3685-96. [PMID: 25030119 PMCID: PMC4176527 DOI: 10.1007/s00436-014-4033-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/04/2014] [Indexed: 11/28/2022]
Abstract
Schistosomes are parasitic worms that have a complex life cycle. The larval stage cercaria, infectious to mammals, is described as highly susceptible to the complement system, largely due to the glycocalyx that covers the cercarial membrane. In an attempt to have a more complete understanding of cercaria reaction to the complement system, three different approaches were used. Live cercariae exposed to normal human serum (NHS) as source of complement factors were assessed for (i) membrane attack complex (MAC) deposition on the parasite surface, (ii) cercaria survival rate by Hoechst staining of parasite DNA, and (iii) transformation into schistosomula by detection of the glucose transporter protein 4 (SGTP4), a marker for new tegument formation. We found that 82-95% of cercariae directly exposed to NHS for 18 h were viable and retained their ability to shed the glycocalyx, suggesting minimal tegument damage. In contrast, inhibition of glycocalyx shedding using eserine caused significant MAC binding and parasite death. Culturing complement-exposed cercariae to measure long-term survival showed that more parasites died over time, reaching a survival rate of 18-31% by day 6 in culture. The reason for this slow death is unknown, but the surviving parasites were able to form a new tegument as shown by detection of SGTP4 on the parasite surface. Furthermore, we found that complement activation significantly damaged the acetabular gland ducts and lysed secretory vesicles released by transforming cercariae. These findings should contribute for future in vivo studies of the effects of the complement system in skin migrating cercariae.
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Affiliation(s)
- Akram A Da'dara
- Department of Infectious Diseases and Global Health, Tufts University Cummings School of Veterinary Medicine, 200 Westboro Rd, North Grafton, MA, 01536, USA
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Dalmasso AP. On the intersections of basic and applied research in xenotransplantation. Xenotransplantation 2012; 19:137-43. [PMID: 22702465 DOI: 10.1111/j.1399-3089.2012.00703.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
I am very grateful to the Council and members of the International Xenotransplantation Association for this Honorary Membership. In accepting this prestigious award, I pay tribute to my mentors Antonio Oriol i Anguera, Carlos Martinez, Robert A. Good, and Hans Müller-Eberhard for their guidance and friendship as I was beginning my travels in biomedical research. I also thank the many gifted collaborators, students, and technical personnel, as well as the agencies and taxpayers, who funded our research and made our scientific contributions possible. Here I briefly mention some of these contributions, including early work on the immunobiology of the thymus, my short incursion in the immunology of Chagas disease, and what have been the dominant themes of my career: the mechanisms of complement injury, the role of complement in pathophysiology, and induction of cytoprotection in the vascular endothelium. I emphasize our contributions on the role of complement as related to understanding and overcoming xenograft injury, a work that has been personally very rewarding. Now it is exciting to see that the field of xenotransplantation research is moving forward vigorously, a time of great optimism suggesting that many potential clinical applications of xenotransplantation will come to fruition in the near future.
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Affiliation(s)
- Agustin P Dalmasso
- Departments of Surgery and of Laboratory Medicine and Pathology, School of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
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Brown MA, Hatfield JK. Mast Cells are Important Modifiers of Autoimmune Disease: With so Much Evidence, Why is There Still Controversy? Front Immunol 2012; 3:147. [PMID: 22701454 PMCID: PMC3369183 DOI: 10.3389/fimmu.2012.00147] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/19/2012] [Indexed: 12/14/2022] Open
Abstract
There is abundant evidence that mast cells are active participants in events that mediate tissue damage in autoimmune disease. Disease-associated increases in mast cell numbers accompanied by mast cell degranulation and elaboration of numerous mast cell mediators at sites of inflammation are commonly observed in many human autoimmune diseases including multiple sclerosis, rheumatoid arthritis, and bullous pemphigoid. In animal models, treatment with mast cell stabilizing drugs or mast cell ablation can result in diminished disease. A variety of receptors including those engaged by antibody, complement, pathogens, and intrinsic danger signals are implicated in mast cell activation in disease. Similar to their role as first responders in infection settings, mast cells likely orchestrate early recruitment of immune cells, including neutrophils, to the sites of autoimmune destruction. This co-localization promotes cellular crosstalk and activation and results in the amplification of the local inflammatory response thereby promoting and sustaining tissue damage. Despite the evidence, there is still a debate regarding the relative role of mast cells in these processes. However, by definition, mast cells can only act as accessory cells to the self-reactive T and/or antibody driven autoimmune responses. Thus, when evaluating mast cell involvement using existing and somewhat imperfect animal models of disease, their importance is sometimes obscured. However, these potent immune cells are undoubtedly major contributors to autoimmunity and should be considered as important targets for therapeutic disease intervention.
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Affiliation(s)
- Melissa A Brown
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
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Caramori ML, Kim Y, Moore JH, Rich SS, Mychaleckyj JC, Kikyo N, Mauer M. Gene expression differences in skin fibroblasts in identical twins discordant for type 1 diabetes. Diabetes 2012; 61:739-44. [PMID: 22315306 PMCID: PMC3282806 DOI: 10.2337/db11-0617] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Clinical studies suggest metabolic memory to hyperglycemia. We tested whether diabetes leads to persistent systematic in vitro gene expression alterations in patients with type 1 diabetes (T1D) compared with their monozygotic, nondiabetic twins. Microarray gene expression was determined in skin fibroblasts (SFs) of five twin pairs cultured in high glucose (HG) for ∼6 weeks. The Exploratory Visual Analysis System tested group differences in gene expression levels within KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways. An overabundance of differentially expressed genes was found in eight pathways: arachidonic acid metabolism (P = 0.003849), transforming growth factor-β signaling (P = 0.009167), glutathione metabolism (P = 0.01281), glycosylphosphatidylinositol anchor (P = 0.01949), adherens junction (P = 0.03134), dorsal-ventral axis formation (P = 0.03695), proteasome (P = 0.04327), and complement and coagulation cascade (P = 0.04666). Several genes involved in epigenetic mechanisms were also differentially expressed. All differentially expressed pathways and all the epigenetically relevant differentially expressed genes have previously been related to HG in vitro or to diabetes and its complications in animal and human studies. However, this is the first in vitro study demonstrating diabetes-relevant gene expression differences between T1D-discordant identical twins. These SF gene expression differences, persistent despite the HG in vitro conditions, likely reflect "metabolic memory", and discordant identical twins thus represent an excellent model for studying diabetic epigenetic processes in humans.
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Affiliation(s)
- M Luiza Caramori
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
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18
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Advances in assay of complement function and activation. Adv Drug Deliv Rev 2011; 63:976-87. [PMID: 21664392 DOI: 10.1016/j.addr.2011.05.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Accepted: 05/26/2011] [Indexed: 12/12/2022]
Abstract
The main function of the complement system is pattern recognition of danger. Typical exogenous danger signals are pathogen associated molecular patterns inducing a protective inflammatory response. Other examples are exposure to foreign surfaces of biomedical materials including nanoparticles, which principally induce the same inflammatory response. If a surface is "foreign" to the host, it induces complement activation. Development of monoclonal antibodies to neoepitopes on complement activation products introduced an entirely new set of methods for assay of complement activation. Activation of complement by a surface occurs by impairment of the fine balance of the control system, e.g. by preferred binding of factor B at the expense of factor H. Sensitive methods to detect complement activation on surfaces and in the fluid phase are a prerequisite for investigation of the biocompatibility of artificial materials. This information can be used to develop new materials with enhanced biocompatibility. Here we review available methods to study human and animal complement function and activation in vitro and in vivo.
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Daha NA, Banda NK, Roos A, Beurskens FJ, Bakker JM, Daha MR, Trouw LA. Complement activation by (auto-) antibodies. Mol Immunol 2011; 48:1656-65. [DOI: 10.1016/j.molimm.2011.04.024] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/15/2011] [Accepted: 04/20/2011] [Indexed: 12/24/2022]
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Black SM, Schott ME, Batdorf BH, Benson BA, Rutherford MS, Levay-Young BK, Dalmasso AP. IL-4 induces protection of vascular endothelial cells against killing by complement and melittin through lipid biosynthesis. Eur J Immunol 2010; 40:803-12. [PMID: 20017192 DOI: 10.1002/eji.200939488] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have shown previously that cytokines IL-4 and IL-13 induce protection in porcine vascular endothelial cells (EC) against killing by the membrane attack complex (MAC) of human complement. This protection is intrinsic, not due to changes in complement regulatory proteins, and requires activation of Akt and sterol receptor element binding protein-1 (SREBP-1), which regulates fatty acid and phospholipid synthesis. Here we report that, compared to EC incubated in medium, IL-4-treated EC had a profound reduction in complement-mediated ATP loss and in killing assessed by vital dye uptake, but only a slight reduction in permeability disruption measured by calcein release. While controls exposed to complement lost mitochondrial membrane potential and subsequently died, protected EC maintained mitochondrial morphology and membrane potential, and remained alive. SREBP-1 and fatty acid synthase activation were required for protection and fatty acid and phospholipid synthesis, including cardiolipin, were increased after IL-4 stimulation, without increase in cholesterol content or cell proliferation. IL-4 also induced protection of EC from killing by the channel forming protein melittin, similar to protection observed for the MAC. We conclude that IL-4 induced activation of Akt/SREBP-1/lipid biosynthesis in EC, resulting in protection against MAC and melittin, in association with mitochondrial protection.
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Affiliation(s)
- Sylvester M Black
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, MN 55455, USA
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The membrane attack complex of complement drives the progression of atherosclerosis in apolipoprotein E knockout mice. Mol Immunol 2009; 47:1098-105. [PMID: 19959238 PMCID: PMC2862291 DOI: 10.1016/j.molimm.2009.10.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/26/2009] [Accepted: 10/29/2009] [Indexed: 11/22/2022]
Abstract
Aims To examine the roles of the membrane attack complex of complement and its sole membrane regulator, CD59, in atherosclerosis. Methods C6 (C6−/−) deficient and CD59a (Cd59a−/−) knockout mice were separately crossed onto the apolipoprotein E knockout (apoE−/−) background. The double knockout mice were fed high-fat diet in order to study the effects of absence of C6 or CD59a on the progression of atherosclerosis. Results C6 deficiency significantly reduced plaque area and disease severity. CD59a had the opposite effect in that deficiency was associated with a significant increase in plaque area, correlating with increased membrane attack complex (MAC) deposition in the plaque and increased smooth muscle cell proliferation in early plaques. Conclusions Our results demonstrate that the MAC contributes to the development of atherosclerosis, C6 deficiency being protective and CD59a deficiency exacerbating disease.
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Rose KL, Paixao-Cavalcante D, Fish J, Manderson AP, Malik TH, Bygrave AE, Lin T, Sacks SH, Walport MJ, Cook HT, Botto M, Pickering MC. Factor I is required for the development of membranoproliferative glomerulonephritis in factor H-deficient mice. J Clin Invest 2008; 118:608-18. [PMID: 18202746 PMCID: PMC2200299 DOI: 10.1172/jci32525] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 11/28/2007] [Indexed: 12/17/2022] Open
Abstract
The inflammatory kidney disease membranoproliferative glomerulonephritis type II (MPGN2) is associated with dysregulation of the alternative pathway of complement activation. MPGN2 is characterized by the presence of complement C3 along the glomerular basement membrane (GBM). Spontaneous activation of C3 through the alternative pathway is regulated by 2 plasma proteins, factor H and factor I. Deficiency of either of these regulators results in uncontrolled C3 activation, although the breakdown of activated C3 is dependent on factor I. Deficiency of factor H, but not factor I, is associated with MPGN2 in humans, pigs, and mice. To explain this discordance, mice with single or combined deficiencies of these factors were studied. MPGN2 did not develop in mice with combined factor H and I deficiency or in mice deficient in factor I alone. However, administration of a source of factor I to mice with combined factor H and factor I deficiency triggered both activated C3 fragments in plasma and GBM C3 deposition. Mouse renal transplant studies demonstrated that C3 deposited along the GBM was derived from plasma. Together, these findings provide what we believe to be the first evidence that factor I-mediated generation of activated C3 fragments in the circulation is a critical determinant for the development of MPGN2 associated with factor H deficiency.
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Affiliation(s)
- Kirsten L Rose
- Molecular Genetics and Rheumatology Section, Faculty of Medicine, Imperial College, Hammersmith Campus, London, United Kingdom
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Suzuki T, Horita S, Kadoya K, Mitsuiki K, Aita K, Harada A, Nitta K, Nagata M. C4d Immunohistochemistry in glomerulonephritis with different antibodies. Clin Exp Nephrol 2007; 11:287-291. [PMID: 18085389 DOI: 10.1007/s10157-007-0496-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2007] [Accepted: 07/29/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND The presence of C4d in the kidney is generally detected particularly for the diagnosis of antibody-mediated rejection in renal transplants. In frozen sections of immunofluorescence (IF) staining with anti-C4d monoclonal antibodies (mAbs), we noted intrinsic C4d deposition even in normal glomeruli though their pathogenic or an intrinsic role is unkown. An anti-C4d polyclonal antibody (C4dpAb), which is suitable for paraffin immunoperoxidase (IP) staining, is less used than mAbs, and it has demonstrated that intrinsic C4d is not evident. To establish a stable and reproducible procedure for C4d detection with the C4dpAb and to determine the staining characteristics of it, the present study aimed to test whether the method was comparable with IF with a mAb. METHODS We compared the C4dpAb with the mAb in adjacent sections of human diseased kidneys, and then compared IP with IF of C4dpAb. Two ways of antigen retrieval was examined for IP. RESULTS On comparing the two antibodies for glomerular staining with IF, we found that the pattern and intensity (C4dpAb showed intrinsic C4d with IF) were similar. In addition, C4dpAb staining with IP and IF demonstrated that the intrinsic staining in the normal glomerulus was mostly undetectable by IP, whereas IF showed distinct staining. Likewise, C4d deposition with IP in some cases was apparently weaker than that on IF, suggesting that this deposition is not intrinsic but indicates pathogenic complement activation. CONCLUSIONS The advantage of the C4dpAb for immunohistochemistry is of value for reconsidering the role of C4d in glomerular diseases.
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Affiliation(s)
- Taisei Suzuki
- Molecular Pathology, Biomolecular and Integrated Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Shigeru Horita
- Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
| | - Koji Kadoya
- The Pathology Department, Matsuyama Red Cross Hospital, Ehime, Japan
| | - Koji Mitsuiki
- The Kidney Center, Matsuyama Red Cross Hospital, Ehime, Japan
| | - Kumi Aita
- Molecular Pathology, Biomolecular and Integrated Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Atsumi Harada
- The Kidney Center, Matsuyama Red Cross Hospital, Ehime, Japan
| | - Kosaku Nitta
- Kidney Center, Tokyo Women's Medical University, Tokyo, Japan
| | - Michio Nagata
- Molecular Pathology, Biomolecular and Integrated Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki, 305-8575, Japan.
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Pickering MC, Warren J, Rose KL, Carlucci F, Wang Y, Walport MJ, Cook HT, Botto M. Prevention of C5 activation ameliorates spontaneous and experimental glomerulonephritis in factor H-deficient mice. Proc Natl Acad Sci U S A 2006; 103:9649-54. [PMID: 16769899 PMCID: PMC1476693 DOI: 10.1073/pnas.0601094103] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membranoproliferative glomerulonephritis (MPGN) type II (dense deposit disease) is an inflammatory renal disease characterized by electron-dense deposits and complement C3 on the glomerular basement membrane. There is no effective therapy. We investigated the role of C5 activation in a model of MPGN that develops spontaneously in complement factor H-deficient mice (Cfh(-/-)). At 12 months there was a significant reduction in mortality, glomerular cellularity, neutrophil numbers, and serum creatinine levels in Cfh(-/-) mice deficient in C5. Excessive glomerular neutrophil numbers, frequently seen in patients with MPGN during disease flares, were also observed in Cfh(-/-) mice after the administration of an antiglomerular basement membrane antibody. This exaggerated injurious phenotype was absent in Cfh(-/-) mice deficient in C5 but not in Cfh(-/-) mice deficient in C6, indicating a key role for C5 activation in the induction of renal lesions. Importantly, the renal injury was completely reversed in Cfh(-/-) mice pretreated with an anti-murine C5 antibody. These results demonstrate an important role for C5 in both spontaneous MPGN and experimentally induced nephritis in factor H-deficient mice and provide preliminary evidence that C5 inhibition therapy might be useful in human MPGN type II.
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Affiliation(s)
- M C Pickering
- Rheumatology Section and Department of Histopathology, Faculty of Medicine, Imperial College, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom.
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Bhakdi S, Tranum-Jensen J. Damage to mammalian cells by proteins that form transmembrane pores. Rev Physiol Biochem Pharmacol 2005; 107:147-223. [PMID: 3303271 DOI: 10.1007/bfb0027646] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Grehan JF, Levay-Young BK, Fogelson JL, François-Bongarçon V, Benson BA, Dalmasso AP. IL-4 and IL-13 induce protection of porcine endothelial cells from killing by human complement and from apoptosis through activation of a phosphatidylinositide 3-kinase/Akt pathway. THE JOURNAL OF IMMUNOLOGY 2005; 175:1903-10. [PMID: 16034134 DOI: 10.4049/jimmunol.175.3.1903] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vascular endothelial cells (EC) perform critical functions that require a balance of cell survival and cell death. EC death by apoptosis and EC activation and injury by the membrane attack complex of complement are important mechanisms in atherosclerosis and organ graft rejection. Although the effects of various cytokines on EC apoptosis have been studied, little is known about their effects on complement-mediated EC injury. Therefore, we studied the abilities of various cytokines to induce protection of porcine aortic EC against apoptosis and killing by human complement, a model of pig-to-human xenotransplantation. We found that porcine EC incubated with IL-4 or IL-13, but not with IL-10 or IL-11, became protected from killing by complement and apoptosis induced by TNF-alpha plus cycloheximide. Maximal protection required 10 ng/ml IL-4 or IL-13, developed progressively from 12 to 72 h of incubation, and lasted 48-72 h after cytokine removal. Protection from complement was not associated with reduced complement activation, C9 binding, or changes in CD59 expression. Inhibition of PI3K prevented development of protection; however, inhibition of p38 MAPK or p42/44 MAPK had no effect. IL-4 and IL-13 induced rapid phosphorylation of Akt. Although protection was inhibited by an Akt inhibitor and a dominant negative Akt mutant transduced into EC, it was induced by transduction of EC with the constitutively active Akt variant, myristylated Akt. We conclude that IL-4 and IL-13 can induce protection of porcine EC against killing by apoptosis and human complement through activation of the PI3K/Akt signaling pathway.
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Affiliation(s)
- John F Grehan
- Department of Surgery, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
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Rangan GK, Pippin JW, Coombes JD, Couser WG. C5b-9 does not mediate chronic tubulointerstitial disease in the absence of proteinuria. Kidney Int 2005; 67:492-503. [PMID: 15673297 DOI: 10.1111/j.1523-1755.2005.67106.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND In nephrotic glomerular diseases, the intratubular assembly of the membrane attack complex (C5b-9) is one of the principal mediators of chronic tubulointerstitial damage. Here, we examined whether C5b-9 has a pathogenic role in tubulointerstitial disease in the absence of proteinuria. METHODS Three pathophysiologically distinct models of nonproteinuric chronic tubulointerstitial disease were induced in Piebald-Viral-Glaxo (PVG) rats, with or without C6 deficiency (C6+ and C6): (1) unilateral ureteric obstruction (UUO, days 1, 3, 6, 14, and 21; N= 5-6/group); (2) cyclosporine (CsA) nephropathy (15 mg/kg SC daily with 0.05% sodium diet; day 14, 35 N= 9/group); and (3) streptozotocin (STZ)-induced diabetes (day 90, N= 8/group). RESULTS The peritubular deposition of C5b-9 increased in all three models. In UUO, the number of vimentin-positive tubules, interstitial volume expansion, and monocyte accumulation were similar in both the C6+ and C6- groups at all time points. There was a trend toward an earlier peak in myofibroblast accumulation in C6- rats with UUO (d3 vs. d6; P= 0.05), but this did not prevent fibrosis at later time points. In CsA nephropathy, cortical tubulointerstitial damage was also similar in both C6+ and C6- groups on day 14, despite equivalent CsA trough levels. Finally, in STZ-induced diabetes, rats did not develop proteinuria, and tubulointerstitial disease (distal tubule glycogen nephrosis, interstitial volume expansion, and tubular dilatation) was not altered by C6 deficiency. CONCLUSION These data suggest that, in contrast to proteinuric states, C5b-9 does not have a significant impact on the progression of tubulointerstitial damage in nonproteinuric chronic renal disease.
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Affiliation(s)
- Gopala K Rangan
- Division of Nephrology, University of Washington Medical Center, Seattle, Washington, USA.
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Cunningham PN, Quigg RJ. Contrasting roles of complement activation and its regulation in membranous nephropathy. J Am Soc Nephrol 2005; 16:1214-22. [PMID: 15800113 DOI: 10.1681/asn.2005010096] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The complement system is involved in defense against microorganisms, the processing of immune complexes and apoptotic debris, and the development of an appropriate immune response. Along with these physiologic effects, complement activation has the potential to result in tissue pathology. To limit this, various complement regulatory proteins (CRP) are present on host cells, including the glomerular podocyte. Experimental data from the Heymann nephritis (HN) rat model of human membranous nephropathy (MN) have shown that IgG antibodies in subepithelial immune deposits initiate complement activation and C5b-9-mediated damage of the overlying podocyte. Although IgG can activate the classical pathway, there also is evidence that alternative pathway activation occurs in MN, which could occur because of absent, dysfunctional, or inhibited podocyte CRP. Related to this are experimental data in HN showing the presence of antibodies that bind and inhibit podocyte CRP; although such antibodies have not been documented in human MN, a decrease in CR1 quantity on the podocyte has been observed. A s a result of a relative lack of CRP and the exposure of activating complement proteins to tubular cells, alternative complement pathway activation and C5b-9-mediated tubular injury can occur in MN and other proteinuric diseases. Overall, in a disease such as MN, the balance between complement regulation and activation is tipped toward its being activated. Therefore, a number of therapeutic approaches have been developed to counteract this, including recombinant forms of endogenous CRP and complement-inhibitory monoclonal antibodies. There is good reason to be optimistic that approaches to block complement activation will become viable therapy for human MN in the future.
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Affiliation(s)
- Patrick N Cunningham
- Section of Nephrology, The University of Chicago, AMB-S523, MC 5100, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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Affiliation(s)
- Leopoldo Raij
- Nephrology-Hypertension Division, Veterans Affairs Medical Center and University of Miami School of Medicine, Miami, Florida 33125, USA.
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Affiliation(s)
- Richard J Quigg
- Section of Nephrology, University of Chicago, Chicago, IL 60637, USA.
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Elliott MK, Jarmi T, Ruiz P, Xu Y, Holers VM, Gilkeson GS. Effects of complement factor D deficiency on the renal disease of MRL/lpr mice. Kidney Int 2004; 65:129-38. [PMID: 14675043 DOI: 10.1111/j.1523-1755.2004.00371.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The alternative complement pathway (AP) is activated in individuals with lupus nephritis and in murine models of systemic lupus erythematosus, including MRL/lpr mice. A previous study from our laboratory evaluated the development of renal disease in MRL/lpr mice genetically deficient in factor B (Bf-/-), a protein necessary for AP activation. MRL/lpr Bf-/- mice developed less renal disease and had improved survival; however, these mice were also a different major histocompatibility complex (MHC) haplotype (H-2b) than their wild-type littermates (H-2k) due to the gene for Bf being located in the MHC gene complex. We undertook the current study to determine if the decreased renal disease in MRL/lpr Bf-/- mice was due to the lack of AP activation or the H-2b haplotype by studying the effects of factor D (Df) deficiency, a critical protein for AP activation, on disease development in MRL/lpr mice. METHODS Df-deficient mice were backcrossed with MRL/lpr mice for four to nine generations. MRL/lpr H-2k Df-/-, Df+/-, and Df+/+ littermates were evaluated for disease development. Lack of AP activation in MRL/lpr Df-/- mice was determined by the zymosan assay. Serum creatinine levels were measured using a creatinine kit. Proteinuria and autoantibody levels were determined by enzyme-linked immunosorbent assay (ELISA). Sections from one kidney were stained with fluorescein isothiocyanate (FITC) alpha-murine C3 or alpha-murine IgG to detect C3 and IgG deposition. The remaining kidney was cut in half with one half fixed, sectioned, and stained with hematoxylin and eosin and periodic acid-Schiff (PAS) to evaluate pathology and another half fixed in glutaraldehyde and examined via electron microscopy. RESULTS MRL/lpr Df-/- mice had similar glomerular IgG deposition, proteinuria and autoantibody levels, as Df+/+ and Df+/- littermates. However, glomerular C3 deposition, serum creatinine levels, and pathologic renal disease were significantly reduced in Df-/- mice. Despite the lack of renal disease in Df-/- mice, life span was not impacted by factor D deficiency. CONCLUSION The absence of Df and AP activation is protective against the development of proliferative renal disease in MRL/lpr mice suggesting the similar effect of Bf deficiency in MRL/lpr mice was also due to the lack of AP activation.
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Affiliation(s)
- Margaret K Elliott
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Bao L, Haas M, Boackle SA, Kraus DM, Cunningham PN, Park P, Alexander JJ, Anderson RK, Culhane K, Holers VM, Quigg RJ. Transgenic expression of a soluble complement inhibitor protects against renal disease and promotes survival in MRL/lpr mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:3601-7. [PMID: 11907125 DOI: 10.4049/jimmunol.168.7.3601] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To investigate the role of complement in lupus nephritis, we used MRL/lpr mice and a transgene overexpressing a soluble complement regulator, soluble CR1-related gene/protein y (sCrry), both systemically and in kidney. Production of sCrry in sera led to significant complement inhibition in Crry-transgenic mice relative to littermate transgene negative controls. This complement inhibition with sCrry conferred a survival advantage to MRL/lpr mice. In a total of 154 animals, 42.5% transgene-negative animals had impaired renal function (blood urea nitrogen > 50 mg/dl) compared with 16.4% mice with the sCrry-producing transgene (p < 0.001). In those animals that died spontaneously, MRL/lpr mice with the sCrry-producing transgene did not die of renal failure, while those without the transgene did (blood urea nitrogen values of 46.6 +/- 9 and 122 +/- 29 mg/dl in transgene-positive and transgene-negative animals, respectively; p < 0.001). Albuminuria was reduced in those transgenic animals in which sCrry expression was maximally stimulated (urinary albumin/creatinine = 12.4 +/- 4.3 and 36.9 +/- 7.7 in transgene-positive and transgene-negative animals, respectively; p < 0.001). As expected in the setting of chronic complement inhibition, there was less C3 deposition in glomeruli of sCrry-producing transgenic mice compared with transgene-negative animals. In contrast, there was no effect on glomerular IgG deposition, levels of anti-dsDNA Ab and rheumatoid factor, or spleen weights between the two groups. Thus, long-term complement inhibition reduces renal disease in MRL/lpr mice, which translates into improved survival. MRL/lpr mice in which complement is inhibited still have spontaneous mortality, yet this is not from renal disease.
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Affiliation(s)
- Lihua Bao
- Department of Medicine, Section of Nephrology, University of Chicago, Chicago, IL 60637, USA
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Salerno CT, Kulick DM, Yeh CG, Guzman-Paz M, Higgins PJ, Benson BA, Park SJ, Shumway SJ, Bolman RM, Dalmasso AP. A soluble chimeric inhibitor of C3 and C5 convertases, complement activation blocker-2, prolongs graft survival in pig-to-rhesus monkey heart transplantation. Xenotransplantation 2002; 9:125-34. [PMID: 11897005 DOI: 10.1034/j.1399-3089.2002.1o042.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Complement plays a critical role in many pathologic processes and in xenograft rejection. Therefore, effective complement inhibitors are of great interest. In pig-to-primate organ transplantation, hyperacute rejection results from antibody deposition and complement activation. Complement activation blocker-2 (CAB-2), a recombinant soluble chimeric protein derived from human decay accelerating factor (DAF) and membrane cofactor protein, inhibits C3 and C5 convertases of both classical and alternative pathways. CAB-2 reduces complement-mediated tissue injury of a pig heart perfused ex vivo with human blood. Therefore, we studied the efficacy of CAB-2 when a pig heart is transplanted heterotopically into rhesus monkeys receiving no immunosuppression. Graft survival in three control monkeys was 1.26 +/- 0.2 h; it was markedly prolonged in eight monkeys that received CAB-2. Of the six monkeys that received a single dose of CAB-2 (15 mg/kg i.v.), four had graft survivals of 21, 95, 96, and 108 h, and two died at 7 to 11 h post-transplant with a beating graft, as a result of technical complications. The two monkeys given multiple doses of CAB-2 had graft survivals of 95 and 96 h. CAB-2 markedly inhibited complement activation, as shown by a strong reduction in generation of C3a and SC5b-9. At graft rejection, tissue deposition of iC3b, C4 and C9 was similar or slightly reduced from controls, and deposition of IgG, IgM, C1q and fibrin did not change. Thus, complement inhibition with CAB-2 abrogates hyperacute rejection of pig hearts transplanted into rhesus monkeys, but does not prevent delayed/acute vascular rejection. These studies demonstrate that the beneficial effects of complement inhibition on survival of a pig heart xenograft in rhesus monkeys are similar to those in other primate species and that CAB-2 may be useful in xenotransplantation and other complement-mediated conditions.
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Lau CL, Daggett WC, Yeatman MF, Chai P, Lin SS, Lodge AJ, Chen EP, Diamond LE, Byrne GW, Logan JS, Parker W, Platt JL, Davis RD. The role of antibodies in dysfunction of pig-to-baboon pulmonary transplants. J Thorac Cardiovasc Surg 2000; 120:29-38. [PMID: 10884652 DOI: 10.1067/mtc.2000.106841] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Pulmonary transplantation has become the preferred treatment for end-stage lung disease, but application of the procedure is limited because of a paucity of donors. One way to solve donor limitations is to use animal organs as a donor source or xenotransplantation. The current barrier to pulmonary xenotransplantation is the rapid failure of the pulmonary xenograft. Although antibodies are known to play a role in heart and kidney xenograft rejection, their involvement in lung dysfunction is less defined. This project was designed to define the role of antibodies in pulmonary graft rejection in a pig-to-baboon model. METHODS Orthotopic transgenic swine left lung transplants were performed in baboons depleted of antibodies by one of three techniques before transplantation: (1) ex vivo swine kidney perfusion, (2) total immunoglobulin-depleting column perfusion, and (3) ex vivo swine lung perfusion. Results were compared with those of transgenic swine lung transplants in unmodified baboons. RESULTS All three techniques of antibody removal resulted in depletion of xenoreactive antibodies. Only pretransplantation lung perfusion improved pulmonary xenograft function compared with lung transplantation in unmodified baboons. CONCLUSIONS The pathogenesis of pulmonary injury in a swine-to-primate transplant model is different from that in renal and cardiac xenografts. Depletion of antibodies alone does not have a beneficial effect and may actually be detrimental.
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Affiliation(s)
- C L Lau
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
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Kulick DM, Salerno CT, Dalmasso AP, Park SJ, Paz MG, Fodor WL, Bolman RM. Transgenic swine lungs expressing human CD59 are protected from injury in a pig-to-human model of xenotransplantation. J Thorac Cardiovasc Surg 2000; 119:690-9. [PMID: 10733757 DOI: 10.1016/s0022-5223(00)70003-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Pulmonary xenotransplantation is currently limited by hyperacute rejection mediated in part by xenoreactive natural antibody and complement. Transgenic swine organs that express the human complement regulatory protein CD59 have demonstrated improved survival in models of pig-to-primate xenotransplantation. OBJECTIVE The purpose of this study was to evaluate transgenic swine lungs that express the human complement regulatory protein CD59 in a model of pig-to-human xenotransplantation. METHODS Transgenic swine lungs (n = 5, experimental group) and outbred swine lungs (n = 6, control group) were perfused with fresh, whole human blood through a centrifugal pump on an ex vivo circuit. Functional data were collected throughout perfusion. Immunoglobulin and complement studies were performed on perfusate samples, and both histologic and immunofluorescent analyses were performed on tissue sections. RESULTS Mean lung survival for the experimental group was increased when compared with controls, 240 +/- 0 minutes versus 35.3 +/- 14.5 minutes, respectively, with a P value of less than.01. A decreased rise in pulmonary vascular resistance at 15 minutes was observed in the experimental group (343 +/- 87 mm Hg. L(-1). min(-1), in contrast to the control group (1579 +/- 722 mm Hg. L(-1). min(-1); P <.01). Pulmonary compliance at 15 minutes was improved for the experimental group versus control group (9.31 +/- 1.41 mL. cm(-2) H(2)O and 4.11 +/- 2.84 mL. cm(-2) H(2)O, respectively; P <.01). SC5b-9 generation in the plasma perfusate was delayed for the experimental group versus the control group. Immunofluorescent examination of tissue sections demonstrated equivalent deposition of immunoglobulin G, immunoglobulin M, C1q, and C3 in both groups, with reduced deposition of C9 in the experimental group. CONCLUSIONS Transgenic swine pulmonary xenografts that express the human complement regulatory protein CD59 demonstrated improved function and survival in an ex vivo model of pig-to-human xenotransplantation.
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Affiliation(s)
- D M Kulick
- Department of Surgery, University of Minnesota, Minneapolis 55455, USA.
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Sato T, Van Dixhoorn MG, Prins FA, Mooney A, Verhagen N, Muizert Y, Savill J, Van Es LA, Daha MR. The terminal sequence of complement plays an essential role in antibody-mediated renal cell apoptosis. J Am Soc Nephrol 1999; 10:1242-52. [PMID: 10361862 DOI: 10.1681/asn.v1061242] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mesangial cell (MC) injury is a characteristic feature in the early phase of Thy.1 nephritis. The present study investigates the contribution of complement to MC apoptosis in this experimental model of kidney disease in rats. Thy.1 nephritis was induced by injection of mouse anti-Thy.1 monoclonal antibody (ER4G). To assess the contribution of the terminal sequence of complement on apoptosis, the studies were performed in complement-sufficient PVG/c (PVG/c+) rats and in rats deficient in complement C6 (PVG/c-). Apoptosis was monitored by assessment of the number of condensed nuclei in kidney sections stained with periodic acid-Schiff (PAS) and by the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) method and expressed as number of apoptotic cells per 50 glomerular cross sections. In the PAS method, 1 h after intravenous injection of ER4G, PVG/c+ rats exhibited 160.9 +/- 49.5 apoptotic cells, whereas PVG/c- rats had only 3.2 +/- 1.4 apoptotic cells. Control rats exhibited 0.9 +/- 0.6 apoptotic cells. These findings were confirmed with the TUNEL method. In PVG/c- rats, a maximum number of 8.8 +/- 3.1 TUNEL-positive (TUNEL+) cells was found at 6 h followed by a decline thereafter. In PVG/c+ rats, apoptosis was associated with deposition of C6 and C5b-9. Restoration of the complement system of PVG/c- rats with purified human C6 resulted in an increase of apoptosis at 1 h after injection of ER4G from minimal numbers to 239.9 +/- 52.4 TUNEL+ cells. These studies appear to indicate for the first time that the terminal sequence of complement is involved in induction of apoptosis.
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Affiliation(s)
- T Sato
- Department of Nephrology, University Hospital Leiden, The Netherlands
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Lin SS, Weidner BC, Byrne GW, Diamond LE, Lawson JH, Hoopes CW, Daniels LJ, Daggett CW, Parker W, Harland RC, Davis RD, Bollinger RR, Logan JS, Platt JL. The role of antibodies in acute vascular rejection of pig-to-baboon cardiac transplants. J Clin Invest 1998; 101:1745-56. [PMID: 9541506 PMCID: PMC508757 DOI: 10.1172/jci2134] [Citation(s) in RCA: 239] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Long-term success in xenotransplantation is currently hampered by acute vascular rejection. The inciting cause of acute vascular rejection is not yet known; however, a variety of observations suggest that the humoral immune response of the recipient against the donor may be involved in the pathogenesis of this process. Using a pig-to-baboon heterotopic cardiac transplant model, we examined the role of antibodies in the development of acute vascular rejection. After transplantation into baboons, hearts from transgenic pigs expressing human decay-accelerating factor and CD59 underwent acute vascular rejection leading to graft failure within 5 d; the histology was characterized by endothelial injury and fibrin thrombi. Hearts from the transgenic pigs transplanted into baboons whose circulating antibodies were depleted using antiimmunoglobulin columns (Therasorb, Unterschleisshein, Germany) did not undergo acute vascular rejection in five of six cases. Biopsies from the xenotransplants in Ig-depleted baboons revealed little or no IgM or IgG, and no histologic evidence of acute vascular rejection in the five cases. Complement activity in the baboons was within the normal range during the period of xenograft survival. In one case, acute vascular rejection of a xenotransplant occurred in a baboon in which the level of antidonor antibody rose after Ig depletion was discontinued. This study provides evidence that antibodies play a significant role in the pathogenesis of acute vascular rejection, and suggests that acute vascular rejection might be prevented or treated by therapies aimed at the humoral immune response to porcine antigens.
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Affiliation(s)
- S S Lin
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Abstract
IgA nephropathy is one of the most common chronic glomerulonephritides worldwide. Since the first publication on IgA nephropathy, a number of clinical and pathological investigations have revealed that the clinical course of patients with IgA nephropathy is extremely diverse, with approximately 10-20% of the patients developing end-stage chronic renal failure. Glomerular changes similar to IgA nephropathy have also been observed in patients with Schoenlein-Henoch purpura, and with other diseases such as liver cirrhosis and chronic inflammatory diseases of the lung. The broad spectrum of clinical and pathological features of IgA nephropathy encompasses a syndrome which includes both primary and secondary IgA nephropathy. The common etiology and pathogenesis of primary and secondary IgA nephropathy appear to be closely related to immunological abnormalities in the production of IgA induced by antigenic stimulation of the common mucosal immune system. IgA is one of the most important humoral factors of the mucosal immune defense system and functions as an antibody against various extrinsic and intrinsic substances. This review describes the Arthus type of IgA immune complex deposition in the glomeruli which can result from persistent or repeated increases in circulating IgA immune complexes. The latter occurs as a consequence of overproduction of IgA antibodies and/or impairment in clearance of IgA immune complexes by the mononuclear phagocytic system. The present review also focuses on the biology of the IgA-mediated immune system and on the etiology, pathogenesis, and animal models of IgA nephropathy.
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Affiliation(s)
- Y Endo
- Department of Immunology, Toranomon Hospital, Okinaka Memorial Institute for Medical Research Tokyo, Japan
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Byrne GW, McCurry KR, Martin MJ, McClellan SM, Platt JL, Logan JS. Transgenic pigs expressing human CD59 and decay-accelerating factor produce an intrinsic barrier to complement-mediated damage. Transplantation 1997; 63:149-55. [PMID: 9000677 DOI: 10.1097/00007890-199701150-00027] [Citation(s) in RCA: 251] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We characterize a line of transgenic pigs that express the human complement-regulatory proteins human CD59 and human decay-accelerating factor. These genes, under the control of heterologous promoters, are expressed in a variety of organs, including the vasculature of the heart, kidney, and liver. We demonstrate that moderate levels of these gene products are sufficient to protect peripheral blood cells from human or baboon complement. Using pig to baboon heterotopic heart transplants, we show that expression of these proteins is sufficient to block the complement-mediated damage that is the hallmark of such xenografts, when nontransgenic organs are used. These results indicate that there is significant species specificity of intrinsic complement regulatory protein function. This specificity is evident in transgenic organs in which low levels of human CD59 and human decay-accelerating factor expression significantly effect the humoral immune response that causes xenograft rejection. This result suggests that transgenic organs with high levels of human complement-regulatory protein expression will be sufficient to alleviate the humoral immunological barriers that currently block the use of xenogeneic organs for human transplantation.
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Affiliation(s)
- G W Byrne
- Nextran, Princeton Forrestal Center, New Jersey 08540, USA
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Müller TF, Kraus M, Neumann C, Lange H. Detection of renal allograft rejection by complement components C5A and TCC in plasma and urine. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1997; 129:62-71. [PMID: 9011592 DOI: 10.1016/s0022-2143(97)90162-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Allograft rejection is associated with complement activation. Yet inconsistent results were obtained in evaluating plasma levels of complement factors or activation products as rejection markers. Therefore the human anaphylatoxin C5a and the soluble terminal complement complex (TCC) were measured by daily enzyme immunoassays on plasma (P) and urine (U) samples from 28 patients undergoing renal transplantation over a mean postoperative period of 25.8 days. The complement levels were evaluated longitudinally (cutoff of 100% increase on the previous day's level) during periods of rejection, stable graft function, acute tubular necrosis, and cytomegalovirus disease. Regarding the detection of 13 acute rejection episodes, U-C5a showed a diagnostic accuracy of 81% (sensitivity of 85%, specificity of 77%), P-C5a one of 62%, and P-TCC one of only 30%. The U-C5a increment (mean rise of 379%) preceded the clinical diagnosis of rejection by an average of 1.6 days. Cytomegalovirus diseases (n = 4) were associated with high P-C5a levels (mean increase of 251% by the time of the first detection of viral DNA). In contrast, resumption of kidney function after acute tubular necrosis (n = 10 periods) was heralded by marked peaks of U-C5a (x = 43.7 microg/l). U-TCC was not detected in any clinical setting. In conclusion, as opposed to P-TCC, U-TCC, and P-C5a, the anaphylatoxin C5a, measured daily in urine, might have potential as an early and reliable marker for acute renal allograft rejection.
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Affiliation(s)
- T F Müller
- Department of Nephrology, Philipps-University of Marburg, Germany
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Kroshus TJ, Bolman RM, Dalmasso AP. Selective IgM depletion prolongs organ survival in an ex vivo model of pig-to-human xenotransplantation. Transplantation 1996; 62:5-12. [PMID: 8693544 DOI: 10.1097/00007890-199607150-00002] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In the pig-to-primate model, xenograft hyperacute rejection (HAR) is mediated by antibody and complement. Previous studies have implicated xenoreactive IgM natural antibody (nAb) as the predominant immunoglobulin involved in HAR. To further evaluate the role of IgM, we selectively reduced IgM levels in human blood, without changing IgG and IgA levels, and then used this blood to perfuse porcine hearts ex vivo. Specific IgM depletion was accomplished with an immunoabsorption column containing sheep anti-human IgM (mu-chain specific) conjugated to Sepharose beads. Human blood was separated into plasma and cellular components. For control experiments, those components were unmodified and recombined in the perfusion system. For experiments with IgM reduced blood, the plasma was passed through the IgM column. Immunoabsorption resulted in approximately 90% reduction in xenoreactive IgM levels, as measured by ELISA. Porcine hearts perfused with unmodified human blood survived 25 +/- 5.6 min (n=5). Porcine hearts perfused with human blood containing reduced levels of IgM survived 229 +/- 45.2 min (n=4; P<0.01). Organ survival was negatively associated with xenoreactive IgM nAb levels measured immediately before perfusion (r=-0.83; P=0.01), and not with IgG nAb levels (r=-0.21; P=0.62). The ability of plasma from IgM-depleted blood to elicit complement activation, measured by iC3b binding to porcine aortic endothelial cells in vitro, was also strongly associated with IgM xenoreactive nAb levels (r=0.92; P<0.0001). Control hearts perfused with unmodified human blood showed typical widespread histologic features of HAR, while porcine hearts perfused with IgM-reduced blood demonstrated milder and less uniform changes. Immunopathological analysis of heart tissues obtained at the completion of each study showed similar deposition of IgG between groups but markedly less IgM, C3, C4, and C9 in the IgM reduction group. These results suggest that selective IgM reduction delays HAR with prolongation of survival and that xenoreactive IgM may be the predominant immunoglobulin involved in HAR in the pig-to-human combination.
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Affiliation(s)
- T J Kroshus
- Department of Surgery, University of Minnesota, Minneapolis, USA
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Nangaku M, Meek RL, Pippin J, Gordon KL, Morgan BP, Johnson RJ, Couser WG. Transfected CD59 protects mesangial cells from injury induced by antibody and complement. Kidney Int 1996; 50:257-66. [PMID: 8807596 DOI: 10.1038/ki.1996.310] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
CD59 is a complement regulatory protein on the glomerular cells that inhibits C5b-9 assembly and insertion. We employed an overexpression strategy to determine the functional significance of CD59 in mesangial cells. We made a CD59 expression vector tagged with FLAG utilizing site-directed mutagenesis and PCR, which allows transfected CD59 to be distinguished from the constitutively expressed protein. In stable clones, overexpressed CD59 was clearly detected immunocytochemically both by anti-FLAG and anti-CD59 antibody in a granular pattern. The overexpression of CD59 was also confirmed by Western blotting. To determine if overexpression of CD59 by mesangial cells protected these cells from C5b-9 attack, we performed complement-mediated cell lysis assays. CD59-transfected mesangial cells demonstrated marked resistance to complement-mediated cell lysis which was reversed in the presence of antibody to CD59. We also investigated the role of CD59 in protecting cells from the effects of membrane insertion of sublytic quantities of C5b-9. Overexpressed CD59 suppressed production of superoxide, one of the inflammatory mediators induced by sublytic C5b-9 attack. These results demonstrate directly that transfected CD59 functions as a potent protector of mesangial cells against both lytic and sublytic attack by C5b-9. CD59 may be an important regulator of complement-mediated disease in the glomerular mesangium.
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Affiliation(s)
- M Nangaku
- Division of Nephrology, University of Washington, Seattle, USA
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Niehans GA, Cherwitz DL, Staley NA, Knapp DJ, Dalmasso AP. Human carcinomas variably express the complement inhibitory proteins CD46 (membrane cofactor protein), CD55 (decay-accelerating factor), and CD59 (protectin). THE AMERICAN JOURNAL OF PATHOLOGY 1996; 149:129-42. [PMID: 8686736 PMCID: PMC1865231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Normal human tissues express membrane-associated complement inhibitory proteins that protect these tissues from damage by autologous complement. To determine whether neoplasms also express these proteins, we examined the distribution of the complement inhibitors decay-accelerating factor (DAF), CD59 (protectin), and membrane cofactor protein in frozen samples of human breast, colon, kidney, and lung carcinomas and in adjacent non-neoplastic tissues, using immunohistochemistry. All samples were also studied for deposition of C3 fragments and activated C5b-9. Differences between normal tissues and the corresponding neoplasms were often observed, with loss or gain of expression of one or more inhibitors. Ductal carcinomas of the breast showed the most variation in phenotype; some tumors expressed only one inhibitor while others expressed different combinations of two or three inhibitors. Colon carcinomas, by contrast, stained intensely for all inhibitors. Renal cell carcinomas had weak to moderate expression of one to three inhibitors, generally DAF and CD59, whereas non-small cell carcinomas of the lung usually expressed CD59 and membrane cofactor protein with variable DAF immunoreactivity. The two small cell carcinomas of the lung showed little or no staining for any inhibitor. Activated C5b-9 deposition was seen adjacent to tumor nests in a minority of carcinomas and showed no correlation with complement inhibitor expression. C3 fragment deposition was minimal. Our results demonstrate that most carcinomas, with the exception of small cell carcinomas of the lung, do express one or more complement inhibitors at a level likely to inhibit complement-mediated cellular damage. Unexpectedly, large quantities of DAF and CD59 were often observed in tumor stroma, with only limited deposition in normal connective tissue. This suggests that carcinomas may supplement the activity of membrane-associated complement inhibitors by release of soluble forms of DAF and CD59 into the surrounding extracellular matrix.
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Affiliation(s)
- G A Niehans
- Pathology and Laboratory Medicine Service, Minneapolis Veterans Affairs Medical Center, MN, USA
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Kroshus TJ, Bolman RM, Dalmasso AP, Rollins SA, Guilmette ER, Williams BL, Squinto SP, Fodor WL. Expression of human CD59 in transgenic pig organs enhances organ survival in an ex vivo xenogeneic perfusion model. Transplantation 1996; 61:1513-21. [PMID: 8633381 DOI: 10.1097/00007890-199605270-00018] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The serious shortage of available donor organs for patients with end stage organ failure who are in need of solid organ transplantation has led to a heightened interest in xenotransplantation. The major barrier to successful discordant xenotransplantation is hyperacute rejection. Hyperacute rejection results from the deposition of preformed antibodies that activate complement on the luminal surface of the vascular endothelium, leading to vessel occlusion and graft failure within minutes to hours. Endogenous membrane-associated complement inhibitors normally protect endothelial cells from autologous complement -- however, these molecules are species-restricted and therefore are ineffective at inhibiting activated xenogeneic complement. To address the pathogenesis of hyperacute rejection in the pig-to-human combination, F1 offspring were generated from a transgenic founder animal that was engineered to express the human terminal complement inhibitor hCD59. High-level cell surface expression of hCD59 was detected in the hearts and kidneys of these transgenic F1 animals, similar to expression levels in human kidney tissue. The hCD59 was expressed on both large vessel and capillary endothelium. Ex vivo perfusion experiments, using human blood as the perfusate, were performed with transgenic porcine hearts and kidneys to evaluate the ability of hCD59 to inhibit hyperacute rejection. These experiments demonstrated that transgenic organs expressing hCD69 resisted hyperacute rejection, as measured by increased organ function for both the hearts and the kidneys, as compared with control pig organs. Hearts from hCD59-expressing animals demonstrated a five-fold prolongation in function compared with controls, 109.8 +/- 20.7 min versus 21.2 +/- 2.9 min (P = 0.164). The hCD59-expressing kidneys also demonstrated significantly prolonged function at 157.8 +/- 27.0 min compared with 60.0 +/- 6.1 min for controls (P = 0.0174). Deposition of C9 neoantigen In the vasculature of porcine organs perfused with human blood was markedly reduced in organs expressing hCD59. These studies demonstrate that C5b-9 plays an important role in hyperacute rejection of a porcine organ perfused with human blood and suggest that donor pigs transgenic for hCD59 may be an integral component of successful clinical xenotransplantation.
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Affiliation(s)
- T J Kroshus
- Department of Surgery, University of Minnesota, Minneapolis, USA
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Diamond LE, McCurry KR, Martin MJ, McClellan SB, Oldham ER, Platt JL, Logan JS. Characterization of transgenic pigs expressing functionally active human CD59 on cardiac endothelium. Transplantation 1996; 61:1241-9. [PMID: 8610425 DOI: 10.1097/00007890-199604270-00021] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The critical shortage of human donor organs has generated interest in the potential for porcine to human xenotransplantation. The initial immunological barrier to xenotransplantation is hyperacute rejection, which is mediated by xenoreactive antibodies and complement, and results in rapid and irreversible tissue destruction. While endogenous complement regulatory proteins (CRPs) protect cells from injury caused by autologous complement, they are relatively species specific and most likely ineffectual in this setting. This has led to the hypothesis that expression of human CRPs in transgenic pigs may affect susceptibility to complement-mediated tissue injury in a porcine-to-human xenograft. Using specific lines of transgenic pigs that express low levels of human CD59, a CRP that acts at the terminal stage of the complement cascade, we present evidence that shows that the human CD59 protein inhibits membrane attack complex assembly and reduces tissue damage when the heart is transplanted to a baboon. Examination by immunohistochemistry of transgenic porcine hearts after transplantation revealed markedly reduced deposition of C5b and MAC, but a similar level of C3 deposition as compared with transplanted control hearts. This finding supports the concept that the species specific function of CRPs contributes to the humoral barrier to xenotransplantation and, given the low level of human CD59 protein expression in the porcine heart, argues that the human protein contributes a unique rather than an additive function in regulation of complement in a xenogeneic setting.
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Brandt J, Pippin J, Schulze M, Hänsch GM, Alpers CE, Johnson RJ, Gordon K, Couser WG. Role of the complement membrane attack complex (C5b-9) in mediating experimental mesangioproliferative glomerulonephritis. Kidney Int 1996; 49:335-43. [PMID: 8821815 DOI: 10.1038/ki.1996.50] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous studies have demonstrated that most pathologic changes in the antithymocyte serum (ATS) model of mesangioproliferative glomerulonephritis are complement-dependent. These include mesangiolysis, glomerular platelet infiltration, mesangial cell proliferation, mesangial cell production of growth factors and phenotypic change to express alpha-actin, glomerular macrophage infiltrate, mesangial matrix expansion, and proteinuria. The mechanism by which complement mediates these effects has not been defined. Because neutrophils do not participate in the ATS model, we hypothesized that the complement effects observed are consequent to glomerular cell insertion of the C5b-9 membrane attack complex of complement. This hypothesis was tested utilizing PVG rats which exhibit an absence of C6 inherited in an autosomal recessive pattern. C6 deficient (C-) PVG rat serum activated by zymosan produced normal amounts of C5a compared to normocomplementemic (C+) PVG rat controls but no C5b-9. When ATS was induced, C- PVG rats had a significant and marked reduction in mesangiolysis, platelet infiltration, mesangial cell proliferation, alpha-actin expression, macrophage infiltration, collagen IV deposition, and proteinuria compared to C+ controls. The reduction in each of these parameters was comparable to that achieved by systemic complement depletion of C+ PVG rats with cobra venom factor. These findings establish the role of C5b-9 in mediating each of the complement-dependent features of the ATS model and indicate that C5b-9 accounts for all of the complement-mediated effects observed. This study provides the first documentation of a functional role for C5b-9 in mediating a non-membranous inflammatory type of glomerular injury in vivo.
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Affiliation(s)
- J Brandt
- Department of Pediatrics, University of Washington, Seattle, USA
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Diamond LE, McCurry KR, Oldham ER, Tone M, Waldmann H, Platt JL, Logan JS. Human CD59 expressed in transgenic mouse hearts inhibits the activation of complement. Transpl Immunol 1995; 3:305-12. [PMID: 8665149 DOI: 10.1016/0966-3274(95)80016-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Porcine-to-human xenotransplantation offers a potential solution to the critical shortage of human organs. The major immunological barrier to xenotransplantation between these species is a rapid rejection process mediated by preformed natural antibodies and complement. Xenogeneic organ grafts are especially susceptible to complement mediated injury because complement regulatory proteins, which ordinarily protect cells from inadvertent injury during the activation of complement, function poorly in regulating activation of heterologous complement. Removal of xenoreactive antibodies or systemic inhibition of complement activity has been shown to prolong graft survival. As an alternative to the systemic inhibition of complement activity, we have established a model system using transgenic animals to test whether the expression of human membrane bound complement regulatory proteins on mouse endothelial cells can inhibit the activation of human complement. CD59, which acts at the terminal stage of complement activation by inhibiting the formation of the membrane attack complex, was used as a paradigm for this model. A CD59 construct containing the putative CD59 gene promoter linked to the CD59 coding region was used to demonstrate expression of the human CD59 protein in various tissues of transgenic mice, including endothelial cells in the heart. In addition, we show that the transgenic CD59 protein is biologically active as determined by the ability to inhibit the formation of membrane attack complex in transgenic mouse hearts perfused ex vivo with human plasma. These results demonstrate that expression of membrane bound complement regulatory proteins can achieve complement inhibition in a xenogeneic organ and suggest that this approach may be useful for successful xenotransplantation between discordant species.
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Affiliation(s)
- L E Diamond
- DNX Biotherapeutics Inc., Princeton, New Jersey 08540, USA
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Kon SP, Coupes B, Short CD, Solomon LR, Raftery MJ, Mallick NP, Brenchley PE. Urinary C5b-9 excretion and clinical course in idiopathic human membranous nephropathy. Kidney Int 1995; 48:1953-8. [PMID: 8587257 DOI: 10.1038/ki.1995.496] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recent reports suggested that the presence of terminal complement complex (C5b-9) in urine from patients with idiopathic membranous nephropathy (IMN) may indicate on-going immunological damage. This report documents the relationship between C5b-9 excretion and clinical outcome in 35 adult patients with biopsy-proven IMN and progressively declining renal function. There were two groups of patients. Group I received one of three treatment regimens: prednisolone alone, prednisolone and chlorambucil, or prednisolone and cyclophosphamide (N = 22). Group II received no immunosuppressive therapy (N = 17). Three of the 18 patients receiving immunosuppressive drugs had more than one treatment regimen as they experienced a clinical relapse during the study period; hence 22 treatments were available for analysis. Urine samples were collected regularly and urinary C5b-9 (uC5b-9) was determined by ELISA. Both groups were similar with respect to age, sex distribution, and the duration of follow-up. An improvement in proteinuria and creatinine clearance was noted in the immunosuppressed group. Thirty-five patients were excreting C5b-9 initially (18 from group I and 17 from group II); 17 patients continued to excrete C5b-9 at the end of the observation period. These 17 patients had a significantly worse clinical outcome when compared to the 18 patients whose C5b-9 excretion became negative, either spontaneously or with treatment (P < 0.005). These results indicate that continuing C5b-9 excretion is correlated with a poor clinical outcome. They also suggest that uC5b-9 is a dynamic marker of ongoing immunological injury, and therefore may be useful in the initial assessment and monitoring of patients with IMN and in identifying patients who may derive benefit from immunosuppressive therapy.
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Affiliation(s)
- S P Kon
- Department of Renal Medicine, Manchester Royal Infirmary, United Kingdom
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Magee JC, Collins BH, Harland RC, Lindman BJ, Bollinger RR, Frank MM, Platt JL. Immunoglobulin prevents complement-mediated hyperacute rejection in swine-to-primate xenotransplantation. J Clin Invest 1995; 96:2404-12. [PMID: 7593628 PMCID: PMC185892 DOI: 10.1172/jci118297] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Immunoglobulins regulate the complement system by activating complement on foreign surfaces and diverting reactive complement proteins away from autologous cell surfaces. Based on this model, we explored the ability of Ig to balance complement activation versus control in a pig-to-primate cardiac xenotransplantation model in which the binding of xenoreactive antibodies of the recipient to graft blood vessels and the activation of complement cause hyperacute rejection. Human IgG added to human serum caused a dose-dependent decrease in deposition of iC3b, cytotoxicity, and heparan sulfate release when the serum was incubated with porcine endothelial cells. This decrease was not caused by alteration in antibody binding or consumption of complement but presumably reflected decreased formation of C3 convertase on the endothelial cells. Infusion of purified human IgG into nonhuman primates prevented hyperacute rejection of porcine hearts transplanted into the primates. As expected, the transplants contained deposits of recipient Ig and C1q but not other complement components. The inhibition of complement on endothelial cell surfaces and in the xenotransplantation model supports the idea that IgG regulates the classical complement pathway and supports therapeutic use of that agent in humoral-mediated disease.
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Affiliation(s)
- J C Magee
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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