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Arakawa S, Suzukawa M, Watanabe K, Kobayashi K, Matsui H, Nagai H, Nagase T, Ohta K. Secretory immunoglobulin A induces human lung fibroblasts to produce inflammatory cytokines and undergo activation. Clin Exp Immunol 2019; 195:287-301. [PMID: 30570135 DOI: 10.1111/cei.13253] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2018] [Indexed: 12/19/2022] Open
Abstract
Immunoglobulin (Ig)A is the most abundant immunoglobulin in humans, and in the airway mucosa secretory IgA (sIgA) plays a pivotal role in first-line defense against invading pathogens and antigens. IgA has been reported to also have pathogenic effects, including possible worsening of the prognosis of idiopathic pulmonary fibrosis (IPF). However, the precise effects of IgA on lung fibroblasts remain unclear, and we aimed to elucidate how IgA activates human lung fibroblasts. We found that sIgA, but not monomeric IgA (mIgA), induced interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1 and granulocyte-macrophage colony-stimulating factor (GM-CSF) production by normal human lung fibroblasts (NHLFs) at both the protein and mRNA levels. sIgA also promoted proliferation of NHLFs and collagen gel contraction comparable to with transforming growth factor (TGF)-β, which is involved in fibrogenesis in IPF. Also, Western blot analysis and real-time quantitative polymerase chain reaction (PCR) revealed that sIgA enhanced production of α-smooth muscle actin (α-SMA) and collagen type I (Col I) by NHLFs. Flow cytometry showed that NHLFs bound sIgA, and among the known IgA receptors, NHLFs significantly expressed CD71 (transferrin receptor). Transfection of siRNA targeting CD71 partially but significantly suppressed cytokine production by NHLFs co-cultured with sIgA. Our findings suggest that sIgA may promote human lung inflammation and fibrosis by enhancing production of inflammatory or fibrogenic cytokines as well as extracellular matrix, inducing fibroblast differentiation into myofibroblasts and promoting human lung fibroblast proliferation. sIgA's enhancement of cytokine production may be due partially to its binding to CD71 or the secretory component.
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Affiliation(s)
- S Arakawa
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan.,Department of Respiratory Medicine, University of Tokyo, Tokyo, Japan
| | - M Suzukawa
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - K Watanabe
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan.,Department of Respiratory Medicine, University of Tokyo, Tokyo, Japan
| | - K Kobayashi
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan.,Department of Respiratory Medicine, University of Tokyo, Tokyo, Japan
| | - H Matsui
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - H Nagai
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
| | - T Nagase
- Department of Respiratory Medicine, University of Tokyo, Tokyo, Japan
| | - K Ohta
- National Hospital Organization Tokyo National Hospital, Tokyo, Japan
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2
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Monteiro RC. Recent advances in the physiopathology of IgA nephropathy. Nephrol Ther 2018; 14 Suppl 1:S1-S8. [PMID: 29606255 DOI: 10.1016/j.nephro.2018.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/01/2018] [Indexed: 01/01/2023]
Abstract
Immunoglobulin A nephropathy or Berger's disease is the most common type of primary glomerulonephritis, which is characterized by IgA1-containing immune-deposits in the glomerular mesangium. Microscopic haematuria and proteinuria are the most common presentations. Mesangial cell proliferation with IgA deposition is found on renal biopsy. Mechanims of the disease implicate at least four key molecules have been implicated in immune complex formation: galactose-deficient IgA1, autoantibodies anti-galactose-deficient-IgA1, soluble CD89 (Fc receptor for IgA) and the CD71 mesangial IgA receptor (transferrin receptor). These factors associated with environmental factors (antigens, food and microbiota) are correlated with disease progression and recurrence after transplantation. This review exploits recent data on the role of these molecular players of the disease, which may improve future therapeutic management of immunoglobulin A nephropathy.
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Affiliation(s)
- Renato C Monteiro
- Inserm U1149 centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; CNRS ERL8252, 16, rue Henri-Huchard, 75018 Paris, France; Laboratoire d'excellence Inflamex, faculté de médecine Bichat, université Paris-Diderot, 16, rue Henri-Huchard, 75018 Paris, France; Service d'immunologie, DHU Fire, hôpital Bichat, 16, rue Henri-Huchard, 75018 Paris, France.
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3
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Jiang H, Liang L, Qin J, Lu Y, Li B, Wang Y, Lin C, Zhou Q, Feng S, Yip SH, Xu F, Lai EY, Wang J, Chen J. Functional networks of aging markers in the glomeruli of IgA nephropathy: a new therapeutic opportunity. Oncotarget 2018; 7:33616-26. [PMID: 27127888 PMCID: PMC5085107 DOI: 10.18632/oncotarget.9033] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 04/11/2016] [Indexed: 12/12/2022] Open
Abstract
IgA nephropathy(IgAN) is the most common primary glomerular disease in China. Primary infections always occur before IgAN. However, the pathology of IgAN is still unclear. Previously we found that LL37, a protein secreted by senescent cells, was specific for the progression of IgAN, and also played a role in the neutrophil function. So we hypothesized that the infiltration of neutrophils, inflammation factors, and aging markers, which were modulated by functional networks, induced the immune response and renal injury. RNA-Sequencing (RNA-seq) can be used to study the whole transcriptome and detect splicing variants that are expressed in a specific cell type or tissue. We separate glomerulus from the renal biopsy tissues. After RNA extraction, the sequences were analyzed with Illumina HiSeq 2000/2500. 381 genes with differential expression between the IgAN patients and the healthy controls were identified. Only PLAU, JUN, and FOS were related to DNA damage, telomere dysfunction-induced aging markers, neutrophil function and IgA nephropathy. The networks showed the possibility of these genes being connected. We conclude that DNA damage and telomere dysfunction could play important roles in IgA nephropathy. In addition, neutrophils are also important factors in this disease. The networks of these markers showed the mechanism pathways that are involved in the duration of the occurrence and progression of IgA nephropathy and might be a new therapeutic opportunity for disease treatment.
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Affiliation(s)
- Hong Jiang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Ludan Liang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Jing Qin
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China.,School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Yingying Lu
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Bingjue Li
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Yucheng Wang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Chuan Lin
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Qin Zhou
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Shi Feng
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
| | - Shun H Yip
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Feng Xu
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - En Yin Lai
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, P.R. China
| | - Junwen Wang
- Centre for Genomic Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jianghua Chen
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, P.R. China.,Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration Of Traditional Chinese Medicine Of China, Hangzhou, P.R. China.,Key Laboratory Of Multiple Organ Transplantation, Ministry Of Health, Key Laboratory Of Nephropathy, Zhejiang, P.R. China
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4
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Zhao YF, Zhu L, Liu LJ, Shi SF, Lv JC, Zhang H. Pathogenic role of glycan-specific IgG antibodies in IgA nephropathy. BMC Nephrol 2017; 18:301. [PMID: 28969604 PMCID: PMC5623975 DOI: 10.1186/s12882-017-0722-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/20/2017] [Indexed: 01/09/2023] Open
Abstract
Background Accumulating evidences proved the important roles of circulating IgA1-containing immune complexes (cIgA1) in IgA nephropathy (IgAN). Galactose-deficient IgA1 (Gd-IgA1) and glycan-specific IgG antibody have been identified as major components in cIgA1. Before, Gd-IgA1 was reported as a vital factor in IgAN, partly via of its pathogenic role to induce mesangial cells activation. However, we still lack direct evidences to clarify the biological effect of glycan-specific IgG antibody in IgAN. Methods In the present study, we enrolled 35 IgAN patients and 17 age- and sex-matched healthy controls. Using uniform aberrant glycosylated IgA1 molecules, and IgG from different individuals, we in vitro prepared IgG-ddIgA1 complexes, and compared the biological differences among these immune complexes regarding their proliferative and inflammatory effects on mesangial cells. Results IgG-ddIgA1 complexes from both patients with IgA nephropathy (IgAN-IgG-dd-IgA1) and healthy controls (HC-IgG-dd-IgA1) could induce the proliferation of mesangial cells and up-regulate expression of MCP-1, IL-6 and CXCL1. The levels of mesangial cells proliferation induced by IgAN-IgG-dd-IgA1 were significantly higher than those induced by HC-IgG-dd-IgA1 (1.10 ± 0.05 vs. 1.03 ± 0.03; p < 0.001). However, the levels of secreted MCP-1, IL-6 and CXCL1 from mesangial cells challenged by IgAN-IgG-dd-IgA1 and HC-IgG-dd-IgA1 were comparable. Conclusions We found that glycan-specific IgG antibodies derived from patients with IgAN had the biological effect to induce mesangial cells proliferation. Moreover, in the present study we also established a method for in vitro preparation of pathogenic IgG-ddIgA1 complexes, which could be applied in future studies exploring IgAN pathogenesis.
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Affiliation(s)
- Yan-Feng Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Peking University Institute of Nephrology, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China. .,Peking University Institute of Nephrology, Beijing, China. .,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China. .,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China. .,Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, No 8, Xishiku Street, Xicheng District, Beijing, 100034, China.
| | - Li-Jun Liu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Peking University Institute of Nephrology, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Su-Fang Shi
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Peking University Institute of Nephrology, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Ji-Cheng Lv
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Peking University Institute of Nephrology, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Peking University Institute of Nephrology, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
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5
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Molyneux K, Wimbury D, Pawluczyk I, Muto M, Bhachu J, Mertens PR, Feehally J, Barratt J. β1,4-galactosyltransferase 1 is a novel receptor for IgA in human mesangial cells. Kidney Int 2017; 92:1458-1468. [PMID: 28750925 DOI: 10.1016/j.kint.2017.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/23/2017] [Accepted: 05/11/2017] [Indexed: 12/29/2022]
Abstract
IgA nephropathy is characterized by mesangial deposition of IgA, mesangial cell proliferation, and extracellular matrix production. Mesangial cells bind IgA, but the identity of all potential receptors involved remains incomplete. The transferrin receptor (CD71) acts as a mesangial cell IgA receptor and its expression is upregulated in many forms of glomerulonephritis, including IgA nephropathy. CD71 is not expressed in healthy glomeruli and blocking CD71 does not completely abrogate mesangial cell IgA binding. Previously we showed that mesangial cells express a receptor that binds the Fc portion of IgA and now report that this receptor is an isoform of β-1,4-galactosyltransferase. A human mesangial cell cDNA library was screened for IgA binding proteins and β-1,4-galactosyltransferase identified. Cell surface expression of the long isoform of β-1,4-galactosyltransferase was shown by flow cytometry and confocal microscopy and confirmed by immunoblotting. Glomerular β-1,4-galactosyltransferase expression was increased in IgA nephropathy. IgA binding and IgA-induced mesangial cell phosphorylation of spleen tyrosine kinase and IL-6 synthesis were inhibited by a panel of β-1,4-galactosyltransferase-specific antibodies, suggesting IgA binds to the catalytic domain of β-1,4-galactosyltransferase. Thus, β-1,4-galactosyltransferase is a constitutively expressed mesangial cell IgA receptor with an important role in both mesangial IgA clearance and the initial response to IgA deposition.
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Affiliation(s)
- Karen Molyneux
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - David Wimbury
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Izabella Pawluczyk
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Masahiro Muto
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Jasraj Bhachu
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Peter R Mertens
- Department of Nephrology and Hypertension, Diabetes and Endocrinology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - John Feehally
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Jonathan Barratt
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.
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6
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Jhee JH, Kang HY, Wu M, Nam BY, Chang TI, Jung SY, Park S, Kim H, Yun HR, Kee YK, Yoon CY, Park JT, Yoo TH, Kang SW, Han SH. Circulating CD89-IgA complex does not predict deterioration of kidney function in Korean patients with IgA nephropathy. ACTA ACUST UNITED AC 2017; 56:75-85. [DOI: 10.1515/cclm-2017-0090] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/17/2017] [Indexed: 12/15/2022]
Abstract
Abstract
Background:
Soluble CD89 (sCD89)-IgA complex plays a key role in the pathogenesis of IgA nephropathy (IgAN). However, there is a lack of evidence supporting this complex as a good biomarker for disease progression. This study aimed to evaluate the usefulness of sCD89-IgA complex for risk stratification of IgAN.
Methods:
A total of 326 patients with biopsy-proven IgAN were included. sCD89-IgA complex was measured by sandwich-enzyme-linked immunosorbent assay. The study endpoints were a 30% decline in estimated glomerular filtration rate (eGFR).
Results:
sCD89-IgA complex levels were inversely and weakly associated with eGFR at the time of biopsy (r=−0.12, p=0.03). However, the significance between the two factors was lost in the multivariate linear regression after adjustment of clinical factors (β=0.35, p=0.75). In a multivariate Cox model, the highest (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.35–1.61; p=0.45) and middle (HR, 0.93; 95% CI, 0.46–1.89; p=0.84) tertiles of sCD89-IgA complex levels were not associated with an increased risk of developing a 30% decrease in eGFR. Furthermore, the decline rates in eGFR did not differ between groups and C-statistics revealed that the sCD89-IgA complex were not superior to clinical factors in predicting disease progression.
Conclusions:
This study found no association between sCD89-IgA complex levels and disease progression in IgAN. Although sCD89 can contribute to the formation of immune complexes, our findings suggest that the sCD89-IgA level is not a good predictor of adverse outcomes and has limited clinical utility as a biomarker for risk stratification in IgAN.
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Affiliation(s)
- Jong Hyun Jhee
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Hye-Young Kang
- Severance Biomedical Science Institute, Brain Korea 21 PLUS , Yonsei University , Seoul , Republic of Korea
| | - Meiyan Wu
- Severance Biomedical Science Institute, Brain Korea 21 PLUS , Yonsei University , Seoul , Republic of Korea
- Department of Nephrology , The First Hospital of Jilin University , Changchun , P.R. China
| | - Bo Young Nam
- Severance Biomedical Science Institute, Brain Korea 21 PLUS , Yonsei University , Seoul , Republic of Korea
| | - Tae-Ik Chang
- Department of Internal Medicine , National Health Insurance Service Medical Center, Ilsan Hospital , Gyeonggi-do , Republic of Korea
| | - Su-Young Jung
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Seohyun Park
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Hyoungnae Kim
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Hae-Ryong Yun
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Youn Kyung Kee
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Chang-Yun Yoon
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Jung Tak Park
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
| | - Shin-Wook Kang
- Department of Internal Medicine , College of Medicine, Institute of Kidney Disease Research , Yonsei University , Seoul , Republic of Korea
- Severance Biomedical Science Institute, Brain Korea 21 PLUS , Yonsei University , Seoul , Republic of Korea
| | - Seung Hyeok Han
- Department of Internal Medicine , Severance Hospital , Yonsei University College of Medicine , 50-1 Yonsei-ro, Seodaemun-gu , Seoul , 120-752, Korea
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7
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Knoppova B, Reily C, Maillard N, Rizk DV, Moldoveanu Z, Mestecky J, Raska M, Renfrow MB, Julian BA, Novak J. The Origin and Activities of IgA1-Containing Immune Complexes in IgA Nephropathy. Front Immunol 2016; 7:117. [PMID: 27148252 PMCID: PMC4828451 DOI: 10.3389/fimmu.2016.00117] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 03/15/2016] [Indexed: 12/12/2022] Open
Abstract
IgA nephropathy (IgAN) is the most common primary glomerulonephritis, frequently leading to end-stage renal disease, as there is no disease-specific therapy. IgAN is diagnosed from pathological assessment of a renal biopsy specimen based on predominant or codominant IgA-containing immunodeposits, usually with complement C3 co-deposits and with variable presence of IgG and/or IgM. The IgA in these renal deposits is galactose-deficient IgA1, with less than a full complement of galactose residues on the O-glycans in the hinge region of the heavy chains. Research from the past decade led to the definition of IgAN as an autoimmune disease with a multi-hit pathogenetic process with contributing genetic and environmental components. In this process, circulating galactose-deficient IgA1 (autoantigen) is bound by antiglycan IgG or IgA (autoantibodies) to form immune complexes. Some of these circulating complexes deposit in glomeruli, and thereby activate mesangial cells and induce renal injury through cellular proliferation and overproduction of extracellular matrix components and cytokines/chemokines. Glycosylation pathways associated with production of the autoantigen and the unique characteristics of the corresponding autoantibodies in patients with IgAN have been uncovered. Complement likely plays a significant role in the formation and the nephritogenic activities of these complexes. Complement activation is mediated through the alternative and lectin pathways and probably occurs systemically on IgA1-containing circulating immune complexes as well as locally in glomeruli. Incidence of IgAN varies greatly by geographical location; the disease is rare in central Africa but accounts for up to 40% of native-kidney biopsies in eastern Asia. Some of this variation may be explained by genetically determined influences on the pathogenesis of the disease. Genome-wide association studies to date have identified several loci associated with IgAN. Some of these loci are associated with the increased prevalence of IgAN, whereas others, such as deletion of complement factor H-related genes 1 and 3, are protective against the disease. Understanding the molecular mechanisms and genetic and biochemical factors involved in formation and activities of pathogenic IgA1-containing immune complexes will enable the development of future disease-specific therapies as well as identification of non-invasive disease-specific biomarkers.
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Affiliation(s)
- Barbora Knoppova
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czech Republic
| | - Colin Reily
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicolas Maillard
- Université Jean Monnet, Saint Etienne, France
- PRES Université de Lyon, Lyon, France
| | - Dana V. Rizk
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Zina Moldoveanu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jiri Mestecky
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Milan Raska
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czech Republic
| | - Matthew B. Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Bruce A. Julian
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
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8
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Abstract
Globally, IgA nephropathy (IgAN) is the most common primary glomerulonephritis that can progress to renal failure. The exact pathogenesis of IgAN is not well defined, but current biochemical and genetic data implicate overproduction of aberrantly glycosylated IgA1. These aberrant immunoglobulins are characterized by galactose deficiency of some hinge-region O-linked glycans. However, aberrant glycosylation alone is insufficient to induce renal injury: the participation of glycan-specific IgA and IgG autoantibodies that recognize the undergalactosylated IgA1 molecule is required. Glomerular deposits of immune complexes containing undergalactosylated IgA1 activate mesangial cells, leading to the local overproduction of cytokines, chemokines and complement. Emerging data indicate that mesangial-derived mediators that are released following mesangial deposition of IgA1 lead to podocyte and tubulointerstitial injury via humoral crosstalk. Patients can present with a range of signs and symptoms, from asymptomatic microscopic haematuria to macroscopic haematuria. The clinical progression varies, with 30-40% of patients reaching end-stage renal disease 20-30 years after the first clinical presentation. Currently, no IgAN-specific therapies are available and patients are managed with the aim of controlling blood pressure and maintaining renal function. However, new therapeutic approaches are being developed, building upon our ever-improving understanding of disease pathogenesis.
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Abstract
Since its first description in 1968, IgA nephropathy has remained the most common form of idiopathic glomerulonephritis leading to chronic kidney disease in developed countries. The exact pathogenesis of IgA nephropathy is still not well defined. Current data implicate an important genetic factor, especially in promoting the overproduction of an aberrant form of IgA1. The immunochemical aberrancy of IgA nephropathy is characterized by the undergalactosylation of O-glycans in the hinge region of IgA1. However, such aberrant glycosylation alone does not cause renal injury. The next stage of disease development requires the formation of glycan-specific IgG and IgA antibodies that recognize the undergalactosylated IgA1 molecule. These antibodies often have reactivity against antigens from extrinsic microorganisms and might arise from recurrent mucosal infection. B cells that respond to mucosal infections, particularly tonsillitis, might produce the nephritogenic IgA1 molecule. With increased immune-complex formation and decreased clearance owing to reduced uptake by the liver, IgA1 binds to the glomerular mesangium via an as yet unidentified receptor. Glomerular IgA1 deposits trigger the local production of cytokines and growth factors, leading to the activation of mesangial cells and the complement system. Emerging data suggest that mesangial-derived mediators following glomerular deposition of IgA1 lead to podocyte and tubulointerstitial injury via mesangio-podocytic-tubular crosstalk. This Review summarizes the latest findings in the pathogenesis of IgA nephropathy.
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Affiliation(s)
- Kar Neng Lai
- Nephrology Center, 10th floor, Li Shu Pui Block, Hong Kong Sanatorium and Hospital, 2 Village Road, Happy Valley, Hong Kong.
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10
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Kaneko Y, Otsuka T, Tsuchida Y, Gejyo F, Narita I. Integrin α1/β1 and α2/β1 as a receptor for IgA1 in human glomerular mesangial cells in IgA nephropathy. Int Immunol 2012; 24:219-32. [DOI: 10.1093/intimm/dxr125] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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11
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Floege J. The Pathogenesis of IgA Nephropathy: What Is New and How Does It Change Therapeutic Approaches? Am J Kidney Dis 2011; 58:992-1004. [DOI: 10.1053/j.ajkd.2011.05.033] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 05/26/2011] [Indexed: 02/07/2023]
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12
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Horton RE, Vidarsson G, Virji M, Williams NA, Heyderman RS. IgA1 antibodies specific for outer membrane protein PorA modulate the interaction between Neisseria meningitidis and the epithelium. Microb Pathog 2009; 46:253-60. [PMID: 19486642 DOI: 10.1016/j.micpath.2009.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Revised: 12/18/2008] [Accepted: 01/29/2009] [Indexed: 01/23/2023]
Abstract
Despite high carriage rates of Neisseria meningitidis, incidence of meningococcal disease remains low, partially due to development of natural immunity. We have previously demonstrated an inverse relationship between salivary anti-meningococcal IgA and disease incidence, but little is known about the contribution of IgA to immunity at mucosal surfaces. Here we show strong immunoreactivity by human salivary IgA against the meningococcal outer membrane porin, PorA. Monomeric anti-PorA IgA1 (humanized chimeric antibodies) but not IgG increased the association of unencapsulated serogroup B N. meningitidis (H44/76) with Chang (conjunctival) but not with either Detroit (pharyngeal) cells or with A549 (alveolar) epithelial cells. Association of encapsulated N. meningitidis was not increased. Epithelial binding of IgA was Fc fragment dependent and not inhibited by IgM. Together these data suggest the presence of a specific epithelial IgA receptor that could influence the effect of both naturally acquired and vaccine induced IgA antibodies at the epithelial surface.
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Affiliation(s)
- R E Horton
- Department of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol, UK.
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13
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Moura IC, Benhamou M, Launay P, Vrtovsnik F, Blank U, Monteiro RC. The glomerular response to IgA deposition in IgA nephropathy. Semin Nephrol 2008; 28:88-95. [PMID: 18222350 DOI: 10.1016/j.semnephrol.2007.10.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Compelling evidence points to a role for IgA receptors in the pathogenesis of IgA nephropathy. The soluble form of the type I IgA receptor (FcalphaRI or CD89) forms complexes with IgA that can be found in patients' serum and that initiate the disease in CD89 transgenic mice. A nonclassic IgA receptor, identified as the transferrin receptor (TfR), is highly expressed in patients' mesangium and colocalizes with IgA deposits. TfR preferentially binds polymeric IgA1 complexes, but not monomeric IgA1 or IgA2. The TfR-IgA1 interaction is dependent on carbohydrate moieties because hypoglycosylated IgA1 has superior binding to TfR than normally glycosylated IgA1. Polymeric IgA1 binding enhances mesangial cell TfR expression and results in cell proliferation and inflammatory and profibrogenic cytokine and chemokine production, suggesting a pivotal role in mesangial cell proliferation, matrix expansion, and recruitment of inflammatory cells. We propose that, as a second event, activation of the classic, FcRgamma-associated transmembrane FcalphaRI expressed on circulating myeloid leukocytes takes place. FcalphaRI/gamma2 cross-linking in human FcalphaRI transgenic animals promotes disease progression by enhancing leukocyte chemotaxis and cytokine production, and IgA immune complexes from IgA nephropathy patients induce FcalphaRI-dependent cell activation. This review therefore details the functional consequences of IgA/receptor interactions and discusses proposed mechanisms to explain the development and chronicity of the disease.
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14
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Gao YH, Xu LX, Zhang JJ, Zhang Y, Zhao MH, Wang HY. Differential binding characteristics of native monomeric and polymeric immunoglobulin A1 (IgA1) on human mesangial cells and the influence of in vitro deglycosylation of IgA1 molecules. Clin Exp Immunol 2007; 148:507-14. [PMID: 17386074 PMCID: PMC1941933 DOI: 10.1111/j.1365-2249.2007.03374.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Recent studies had demonstrated that serum and mesangial immunoglobulin A1 (IgA1) in patients with IgA nephropathy (IgAN) were polymeric and deglycosylated. The current study was to investigate the binding characteristics of monomeric and polymeric normal human IgA1 on mesangial cells and the influence of in vitro deglycosylation of IgA1 molecules. The normal human IgA1 was desialylated and degalactosylated with specific enzymes, respectively. The monomeric IgA1 (mIgA1) and polymeric IgA1 (pIgA1) were separated by Sephacryl S-300 chromatography. The binding capacities of the mIgA1 and pIgA1 to primary human mesangial cells (HMC) were evaluated by classical radioligand assay. Both the native mIgA1 and pIgA1 could bind to HMC in a dose-dependent and saturable manner. The maximal binding capacity of the native pIgA1 were significantly higher than that of the native mIgA1 (P < 0.05). However, the affinity of the native mIgA1 was almost 100 times higher than that of the native pIgA1. After deglycosylation, binding of the two deglycosylated mIgA1 to HMC could not be detected. However, the maximal binding capacities of the two deglycosylated pIgA1 to HMC were increased significantly compared with that of native pIgA1. The affinity of the two deglycosylated pIgA1 was similar to that of native pIgA1 (P > 0.05). The current study suggests differential binding characteristics of native monomeric and polymeric IgA1 on mesangial cells. Glycosylation of IgA1 molecules could significantly affect the binding of IgA1 on HMC.
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Affiliation(s)
- Y-H Gao
- Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
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15
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Yan Y, Xu LX, Zhang JJ, Zhang Y, Zhao MH. Self-aggregated deglycosylated IgA1 with or without IgG were associated with the development of IgA nephropathy. Clin Exp Immunol 2006; 144:17-24. [PMID: 16542360 PMCID: PMC1809625 DOI: 10.1111/j.1365-2249.2006.03026.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
IgA nephropathy (IgAN) is the most common primary glomerulonephritis, with various pathological phenotypes. Our previous study suggested that aberrant glycosylation of serum IgA1 was associated with different pathological phenotypes of IgAN, and substantial evidence indicated that deglycosylated IgA1 had an increased tendency to form macromolecules. The aim of the current study was to investigate the composition of IgA1-containing macromolecules in different pathological phenotypes of IgAN. Sera from 10 patients with mild mesangial proliferative IgAN (mIgAN), 10 with focal proliferative sclerosing IgAN (psIgAN) and 10 healthy blood donors were collected. The sera were applied and IgA1 binding proteins (IgA1-BP) were eluted from the columns immobilized with desialylated IgA1 (DesIgA1/Sepharose) or desialylated/degalactosylated IgA1 (DesDeGalIgA1/Sepharose), respectively. The amounts of IgA1 and IgG and the glycoform of IgA1 in the IgA1-BP were detected by enzyme-linked immunosorbent assays (ELISAs) and were compared between patients with different pathological phenotypes and normal controls. The amount of IgA1 in IgA1-BP eluted from both columns was significantly higher in patients with both pathological phenotypes of IgAN than in normal controls. In IgA1-BP eluted from DesDeGalIgA1/Sepharose, the desialylation of IgA1 was much more pronounced in patients with both pathological phenotypes of IgAN than in normal controls, while the degalactosylation of IgA1 was much more pronounced only in patients with psIgAN than in normal controls. Furthermore, the amount of IgG in IgA1-BP eluted from DesDeGalIgA1/Sepharose was significantly higher in patients with psIgAN than in normal controls. In patients with psIgAN, the amount of IgG eluted from DesDeGalIgA1/Sepharose was much greater than from DesIgA1/Sepharose. In conclusion, self-aggregated deglycosylated IgA1 with or without IgG were associated with the development of IgAN.
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Affiliation(s)
- Y Yan
- Institute of Renal Division, Peking University First Hospital, Beijing, China
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16
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Zhang JJ, Xu LX, Zhang Y, Zhao MH. Binding capacity of in vitro deglycosylated IgA1 to human mesangial cells. Clin Immunol 2006; 119:103-9. [PMID: 16442846 DOI: 10.1016/j.clim.2005.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 09/23/2005] [Accepted: 12/02/2005] [Indexed: 11/20/2022]
Abstract
IgA nephropathy (IgAN) is the most common glomerular disease and it is characterized by deposition of IgA1 molecules in mesangium. Recent studies had demonstrated that serum and mesangial IgA1 in IgAN were deglycosylated and IgA1 could bind to human mesangial cells (HMC) through a novel receptor. The aim of the current study is to investigate and compare the binding capacities of different in vitro deglycosylated IgA1 on human mesangial cells. Serum IgA1 was purified by jacalin affinity chromatography and then was desialylated (DesIgA1) and/or degalactosylated (Des/DeGalIgA1) with neuraminidase and/or beta-galactosidase. The efficacy of deglycosylations was assessed by Peanut agglutinin (PNA) and Vicia villosa (VV) lectin. The sizes of normal IgA1 and deglycosylated IgA1 were determined by Sephacryl S-300 chromatography and binding capacities to primary HMC were evaluated by radioligand binding assays. Normal IgA1 and deglycosylated IgA1 could bind to HMC in a dose-dependent, saturable manner. The maximal binding capacities and binding sites/cell of DesIgA1 and Des/DeGalIgA were significantly higher than that of normal IgA1. However, more aggregated IgA1 was found in DesIgA1 and Des/DeGalIgA1. Scatchard analysis revealed a similar Kd of normal IgA1 and deglycosylated IgA1. The current study suggested that the binding capacities of DesIgA1 and Des/DeGalIgA1 to HMC were significantly higher than that of normal IgA1, which at least in part was due to more macromolecular IgA1 in deglycoslated IgA1. However, there were no significant differences in the affinities of normal IgA1, DesIgA1 and Des/DeGalIgA1 with HMC. Deglycosylated IgA1 might play an important role in pathogenesis of IgAN.
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Affiliation(s)
- Jun-jun Zhang
- Renal Division and Institute of Nephrology, Peking University First Hospital, Beijing 100034, PR China
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17
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Demeule B, Gurny R, Arvinte T. Where disease pathogenesis meets protein formulation: Renal deposition of immunoglobulin aggregates. Eur J Pharm Biopharm 2006; 62:121-30. [PMID: 16221544 DOI: 10.1016/j.ejpb.2005.08.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 08/11/2005] [Indexed: 10/25/2022]
Abstract
Aggregation is one of the important issues encountered during the development of immunoglobulin-based drugs. The aim of the current review is to discuss the causes and consequences of immunoglobulin aggregation as well as the relevance of immunoglobulin aggregation to disease pathogenesis. Extracellular deposition of immunoglobulins, either monoclonal light chains or intact polyclonal antibodies, induces renal failure in various nephropathies. The aggregates can present fibrillar or amorphous structures. In this review, factors known to influence protein aggregation, such as the primary structure of the protein, local environment and glycosylation are assessed, as well as the subsequent altered clearance, fibril formation and toxicity. The role of the protein local environment is emphasized. Even if the local environment causes only minor perturbations in the protein structure, these perturbations might be sufficient to trigger aggregate formation. This fact underlines the importance of choosing appropriate formulations for protein drugs. If the formulation provides a slightly destabilizing environment to the protein, the long-term stability of the drug may be compromised by aggregate formation.
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Affiliation(s)
- Barthélemy Demeule
- School of Pharmaceutical Sciences, EPGL, University of Geneva, Switzerland
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18
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Yoo EM, Morrison SL. IgA: an immune glycoprotein. Clin Immunol 2005; 116:3-10. [PMID: 15925826 DOI: 10.1016/j.clim.2005.03.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 02/24/2005] [Accepted: 03/15/2005] [Indexed: 10/25/2022]
Abstract
IgA is a glycoprotein containing multiple N-linked carbohydrates as well as O-linked glycans in the case of IgA1. Because of the critical role it plays in providing protection at mucosal surfaces, IgA is an ideal candidate for use as a therapeutic or prophylactic agent. The presence or absence of carbohydrates, as well as their structure, has been found to influence effector functions and binding to specific IgA receptors. In addition, changes in IgA glycosylation are associated with immune pathology. A thorough understanding of the contributions of the glycans to IgA immune protection will aid in the design of clinically suitable antibodies.
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Affiliation(s)
- Esther M Yoo
- Department of Microbiology, Immunology and Molecular Genetics, University of California, 609 Charles E. Young Drive, Los Angeles, CA 90095, USA.
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19
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Moura IC, Arcos-Fajardo M, Gdoura A, Leroy V, Sadaka C, Mahlaoui N, Lepelletier Y, Vrtovsnik F, Haddad E, Benhamou M, Monteiro RC. Engagement of transferrin receptor by polymeric IgA1: evidence for a positive feedback loop involving increased receptor expression and mesangial cell proliferation in IgA nephropathy. J Am Soc Nephrol 2005; 16:2667-76. [PMID: 15987753 DOI: 10.1681/asn.2004111006] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
IgA nephropathy (IgAN), the most common primary glomerulonephritis in the world, is characterized by IgA immune complex-mediated mesangial cell proliferation. The transferrin receptor (TfR) was identified previously as an IgA1 receptor, and it was found that, in biopsies of patients with IgAN, TfR is overexpressed and co-localizes with IgA1 mesangial deposits. Here, it is shown that purified polymeric IgA1 (pIgA1) is a major inducer of TfR expression (three- to four-fold increase) in quiescent human mesangial cells (HMC). IgA-induced but not cytokine-induced HMC proliferation is dependent on TfR engagement as it is inhibited by both TfR1 and TfR2 ectodomains as well as by the anti-TfR mAb A24. It is dependent on the continued presence of IgA1 rather than on soluble factors released during IgA1-mediated activation. In addition, pIgA1-induced IL-6 and TGF-beta production from HMC was specifically inhibited by mAb A24, confirming that pIgA1 triggers a TfR-dependent HMC activation. Finally, upregulation of TfR expression induced by sera from patients with IgAN but not from healthy individuals was dependent on IgA. It is proposed that deposited pIgA1 or IgA1 immune complexes could initiate a process of auto-amplification involving hyperexpression of TfR, allowing increased IgA1 mesangial deposition. Altogether, these data unveil a functional cooperation between pIgA1 and TfR for IgA1 deposition and HMC proliferation and activation, features that are commonly implicated in the chronicity of mesangial injuries observed in IgAN and that could explain the recurrence of IgA1 deposits in the mesangium after renal transplantation.
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Affiliation(s)
- Ivan C Moura
- INSERM U699, Bichat Medical School, 75870 Paris, Cedex 18, France
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20
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Novak J, Tomana M, Matousovic K, Brown R, Hall S, Novak L, Julian BA, Wyatt RJ, Mestecky J. IgA1-containing immune complexes in IgA nephropathy differentially affect proliferation of mesangial cells. Kidney Int 2005; 67:504-13. [PMID: 15673298 DOI: 10.1111/j.1523-1755.2005.67107.x] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Sera of patients with IgA nephropathy (IgAN) contain circulating immune complexes (CIC) composed of galactose-deficient IgA1 complexed with antiglycan antibodies. The role of these CIC in the pathogenesis of IgAN is not known. METHODS We studied how proliferation of cultured mesangial cells (MC) is affected by CIC prepared from sera of IgAN patients and healthy control subjects using size-exclusion chromatography. CIC-containing fractions were added to serum-starved MC in culture, and cell proliferation was measured using (3)H-thymidine incorporation. The results were confirmed by staining MC using an antibody against proliferating cell nuclear antigen. RESULTS The incubation of starved MC with serum fractions with M(r) 800 to 900 kD, rich with galactose-deficient IgA1, stimulated proliferation, while fractions with smaller complexes were inhibitory. Furthermore, CIC-containing larger molecular mass fractions isolated from serum of an IgAN patient collected during an episode of macroscopic hematuria stimulated MC proliferation more than CIC obtained during a subsequent quiescent phase. To examine the role of IgA, we removed IgA1 from serum before fractionation. The resultant IgA1-depleted fractions were devoid of stimulatory IgA-CIC. Sera of IgAN patients were also fractionated after addition of desialylated galactose-deficient polymeric IgA1 to form additional immune complexes. Supplementation with a small quantity of this IgA1 increased cellular proliferation in assays using serum fractions of M(r)>/=800 to 900 kD; uncomplexed IgA1 did not affect MC proliferation significantly. In contrast, supplementation with a larger quantity of this IgA1 inhibited cellular proliferation in assays using serum fractions of M(r) 700 to 800 kD. CONCLUSION Overall, these findings suggest that CIC containing aberrantly glycosylated IgA1 affect proliferation of MC in vitro and, thus, likely play a role in the pathogenesis of IgAN.
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Affiliation(s)
- Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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21
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Abstract
Primary IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis, leading to progressive renal failure in almost one third of the patients. The disease is characterized by mesangial deposits of IgA. The pathogenesis of IgAN remains incompletely understood. The basic abnormality of this disorder lies within the IgA immune system rather than in the kidney. Elevated levels of IgA and IgA-containing complexes are found in sera of most patients with IgAN, but increased levels alone are not sufficient to develop IgAN. Therefore abnormal physicochemical properties of circulating IgA, such as size, charge, and glycosylation may play a role. This is supported by the presence of altered glycosylation of serum and mesangial IgA in patients with IgAN. Although the precise origin and nature of the mesangial IgA deposits are still uncertain, they contain at least in part macromolecular IgA, which may be derived from circulating IgA-containing complexes. Recently, novel insights have been obtained in the molecular composition of circulating high-molecular-weight IgA, which might include complexes with underglycosylated IgA1 and IgA-CD89 complexes. In this review various aspects of macromolecular IgA in relation to IgAN will be discussed.
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Affiliation(s)
- Paul J M van der Boog
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
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22
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Lai KN, Tang SCW, Guh JY, Chuang TD, Lam MF, Chan LYY, Tsang AWL, Leung JCK. Polymeric IgA1 from patients with IgA nephropathy upregulates transforming growth factor-beta synthesis and signal transduction in human mesangial cells via the renin-angiotensin system. J Am Soc Nephrol 2004; 14:3127-37. [PMID: 14638911 DOI: 10.1097/01.asn.0000095639.56212.bf] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The effects of polymeric IgA1 (pIgA1) and monomeric IgA1 (mIgA1) from patients with IgA nephropathy (IgAN) on the renin-angiotensin system (RAS) and TGF-beta synthesis were examined in cultured human mesangial cells (HMC). Both pIgA1 and mIgA1 induced renin gene expression in HMC, in a dose-dependent manner. Similar findings were observed for TGF-beta gene and protein expression. The values measured in HMC incubated with pIgA1 were significantly higher than those in HMC incubated with equivalent amounts of mIgA1. When similar experiments were performed with the addition of either captopril or losartan, there was a significant increase in the renin gene expression by HMC, whereas the synthesis of TGF-beta was markedly reduced. The TGF-beta signal transduction pathways in HMC were studied by measuring the receptor-regulated Smad proteins (Smad 2 and 3) and common-partner Smad proteins (Smad 4). pIgA1 from patients with IgAN upregulated Smad activity in HMC, and the activity observed in HMC that had been preincubated with pIgA1 was readily suppressed with optimal concentrations of captopril or losartan. The effects of pIgA1 on the RAS were further examined in HMC incubated with IgA isolated from 30 patients with IgAN, 30 healthy subjects, and disease control subjects with other diseases. pIgA1 induction of angiotensin II or TGF-beta synthesis in HMC was significantly greater with preparations from patients with IgAN, compared with healthy or disease control subjects. The findings support a pathogenetic role of pIgA1 in IgAN through upregulation of the RAS and TGF-beta, leading to chronic renal failure with renal fibrosis.
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Affiliation(s)
- Kar Neng Lai
- Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong.
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23
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Wang Y, Zhao MH, Zhang YK, Li XM, Wang HY. Binding capacity and pathophysiological effects of IgA1 from patients with IgA nephropathy on human glomerular mesangial cells. Clin Exp Immunol 2004; 136:168-75. [PMID: 15030528 PMCID: PMC1809001 DOI: 10.1111/j.1365-2249.2004.02408.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
IgA deposition in glomerular mesangium and the interaction with mesangial cells may well be the final common pathway to IgA nephropathy (IgAN). Altered hinge-region O-glycosylation of IgA1 from patients with IgAN may predispose to mesangial deposition and activation of the mesangial cell (MC) by IgA1, via a novel IgA1 receptor, and may be a key event in the pathogensis of IgAN. The aim of this study was to investigate the binding capacity and biological effects of IgA1, from both patients with IgAN and healthy controls, on human mesangial cells (HMC). Serum IgA1 was isolated with jacalin affinity chromatography, heated to aggregated form (aIgA1) and labelled with (125)I. Binding capacity of aIgA1 in vitro to cultured primary HMC was evaluated by a radioligand binding assay and the specificity of binding was determined by a competitive inhibition assay. Intracellular calcium release was studied by confocal analysis and phosphorylation of extracellular signal-regulated kinase (ERK) was determined by Western blot analysis. Change of cell cycles was demonstrated by flow cytometry and HMC proliferation was evaluated by direct cell count. Expression of TGF-beta mRNA and production of supernatant fibronectin were tested by RT-PCR and indirect competitive ELISA, respectively. aIgA1 from both the patients with IgAN and normal controls bound to HMC in a dose-dependent, saturable manner, and was saturated at approximately 500 pmoles per 0.5 ml of aIgA1. aIgA1 from patients with IgAN, however, bound to HMC at a higher speed and Scatchard analysis revealed a Kd of (8.89 +/- 2.1) x 10(-8)m versus (4.3 +/- 1.2) x 10(-7)m for aIgA1 from healthy controls (P = 0.026). The binding was specific because it was only inhibited by unlabelled Mono-IgA1 (mIgA1) and not by serum albumin or IgG. aIgA1 from patients with IgAN could induce release of intracellular calcium, phosphorylation of ERK, DNA synthesis, proliferation of HMC, expression of TGF-betamRNA and secretion of fibronectin in HMC in a similar time-dependent manner as aIgA1 from healthy controls, but the effects were much stronger and the durations were much longer (P < 0.05, respectively). We conclude that aIgA1 from patients with IgAN has a higher binding capacity to HMC and stronger biological effects than aIgA1 from healthy controls. This suggests that direct interaction between IgA1 and HMC and subsequential pathophysiological responses may play an important role in the pathogenesis for IgAN.
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Affiliation(s)
- Y Wang
- Renal Division & Institute of Nephrology, Peking University First Hospital, Beijing, China
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24
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Matsumura S, Van De Water J, Leung P, Odin JA, Yamamoto K, Gores GJ, Mostov K, Ansari AA, Coppel RL, Shiratori Y, Gershwin ME. Caspase induction by IgA antimitochondrial antibody: IgA-mediated biliary injury in primary biliary cirrhosis. Hepatology 2004; 39:1415-22. [PMID: 15122771 DOI: 10.1002/hep.20175] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Anti-mitochondrial antibodies (AMAs) have long been recognized as a serological hallmark of primary biliary cirrhosis (PBC). Although high titers of immunoglobulin (Ig)A AMAs are found in bile, saliva, and urine of patients, a pathogenic role for this antibody has remained elusive. Functional studies of this IgA in general have been impeded by low quantities of antibody and the inability to recover antigen-specific IgA in dimeric form. Using a newly defined synthetic group A. Streptococcus derived peptide, we purified large quantities of dimeric and monomeric IgA from patient sera. The purified IgA was incubated with Madine-Darby canine kidney (MDCK) cells transfected with the human polymeric Ig receptor (pIgR) and the cells studied by flow cytometric analysis for binding of carboxyfluorescein conjugated VAD-fmk peptide to activated caspase enzymes. A total of 87% of PBC patients that were anti-PDC-E2 positive had serum IgA that increased caspase activation in MDCK-pIgR+ cells compared to serum-derived IgA from controls with a maximum reaction 48 hours after addition of IgA. The titer of anti-PDC-E2 IgA among the PBC patients strongly correlated with caspase activation (cc = 0.88). Pre-absorption of the IgA using recombinant 2-oxo-acid dehydrogenase complex significantly diminished this activation. IgG from the same PBC patients did not induce caspase activation. These data suggest that during transcytosis through pIgR-positive cells, exposure to PDC-E2-specific dimeric IgA results in the initiation of caspase activation. In conclusion, we propose that due to an even greater concentration of dimeric IgA in biliary and mucosal secretions, constant transcytosis would render the exposed cells more susceptible to apoptosis resulting in subsequent bile duct damage.
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Affiliation(s)
- Shuji Matsumura
- Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis, Davis, CA 95616, USA
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25
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Abstract
Immunoglobulin A (IgA) nephropathy is an immune-complex-mediated glomerulonephritis characterized by the presence of immunoglobulin A deposits in mesangial and paramesangial regions. The patients with IgA nephropathy present with varying clinical symptoms (eg, microhematuria with preserved renal function or progressive deterioration of renal functions resulting in end-stage renal disease). The factors involved in the pathogenetic mechanisms of IgA nephropathy include (1). environmental factors, (2). genetic factors, (3). abnormality of the IgA1 molecule, and (4). various inflammatory mediators. The gene polymorphism studies for human leukocyte antigen (HLA), renin-angiotensin-aldosterone system, and selectin gene clusters, suggest a certain degree of genetic predisposition in patients for IgA nephropathy. Also, the genome-wide screening in familial IgA nephropathy showed linkage of IgA nephropathy to the 6q22-23 chromosome. Besides genetic influence in its pathogenesis, aberrant galactosylation in serum IgA and IgA1 eluted from kidneys with IgA nephropathy has been observed, and conceivably such abnormalities induce the expression of various cytokines, interleukin (IL)-6, platelet-derived growth factor (PDGF), tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta1 in the renal cells, which contributes to further glomerular injury. Despite an enormous amount of information available in the literature, further studies are needed to delineate the precise pathogenetic mechanisms involved in primary IgA nephropathy and also to facilitate the development of newer therapeutic interventions.
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Affiliation(s)
- Jun Wada
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
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26
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van der Boog PJM, De Fijter JW, Van Kooten C, Van Der Holst R, Van Seggelen A, Van Es LA, Daha MR. Complexes of IgA with FcalphaRI/CD89 are not specific for primary IgA nephropathy. Kidney Int 2003; 63:514-21. [PMID: 12631116 DOI: 10.1046/j.1523-1755.2003.00756.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The presence of IgA together with the myeloid IgA-receptor FcalphaRI/CD89 in the circulation of patients with IgA nephropathy (IgAN) has been suggested as a specific pathogenic factor for mesangial deposition. However, in a recent study we found these complexes also in serum samples from healthy subjects. To investigate whether these circulating complexes are specific for IgAN, the levels and characteristics of IgA-CD89 complexes were analyzed in patients with IgAN and healthy controls. METHODS Specific ELISAs with different poly- and monoclonal antibodies and a sensitive dot-blot method were used to measure IgA-CD89 levels in serum and purified IgA samples obtained from healthy volunteers (N = 30) and patients with IgAN (N = 35). Fractionated samples of purified IgA were used to compare the size characteristics of the IgA-CD89 complexes. RESULTS Almost all CD89 in serum of patients with IgAN and controls was associated with high molecular weight IgA. Quantitative analysis of IgA-CD89 complexes in purified IgA revealed no significant difference between patients with IgAN and controls. No correlation was found between levels of IgA-CD89 complexes and clinical parameters associated with progressive IgAN. CONCLUSIONS CD89 in the circulation is found mainly linked to high molecular weight IgA. The presence of these complexes is not specific for IgAN. Therefore, if IgA-CD89 complexes are involved in the pathogenesis of primary IgA nephropathy, additional factors are required to explain the IgA-CD89 complex-mediated renal inflammation.
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Affiliation(s)
- Paul J M van der Boog
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
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27
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Novak J, Vu HL, Novak L, Julian BA, Mestecky J, Tomana M. Interactions of human mesangial cells with IgA and IgA-containing immune complexes. Kidney Int 2002; 62:465-75. [PMID: 12110007 DOI: 10.1046/j.1523-1755.2002.00477.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is characterized by IgA1-containing immune complexes in mesangial deposits and in the circulation. The circulating immune complexes (CIC) are composed of galactose- (Gal) deficient IgA1 and IgG or IgA1 antibodies specific for the Gal-deficient IgA1; interactions of these CIC with mesangial cells (MC) were studied. METHODS Binding, internalization, and catabolic degradation of myeloma IgA1 protein as a standard control and the isolated CIC were studied using human MC, hepatoma cell line HepG2 expressing the asialoglycoprotein receptor (ASGP-R), and monocyte-like cell line U937 expressing the Fc(alpha)-R (CD89). Biochemical and molecular approaches were used to assess expression of CD89 and ASGP-R by MC. RESULTS At 4 degrees C, radiolabeled IgA1 bound to MC and HepG2 cells in a dose-dependent and saturable manner. The binding was inhibited by IgA-containing CIC or excess IgA1 or its Fc fragment but not by the Fab fragment of IgA1. At 37 degrees C, the cell-bound IgA1 was internalized and catabolized. In addition to IgA1, HepG2 cells also bound (in a Ca2+-dependent manner), internalized, and catabolized asialoorosomucoid (ASOR), other asialo-(AS)-glycoproteins, and secretory component (SC). The binding by MC appeared to be restricted to IgA1 or AS-IgA1 and was not Ca2+-dependent. Furthermore, MC and HepG2 cells internalized and catabolized IgA1-containing CIC. Using RT-PCR with ASGP-R- or CD89-specific primers, mRNAs of the two respective genes were not detected in MC. CONCLUSIONS The data showed that the ability of MC to bind IgA1 and IgA1-containing CIC in vitro was mediated by an IgA receptor that was different from CD89 or ASGP-R and had a higher affinity for IgA-CIC than for uncomplexed IgA.
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Affiliation(s)
- Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294,USA.
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28
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29
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LAI KN, LEUNG JCK. Pathogenic role of the IgA molecule in IgA nephropathy. Nephrology (Carlton) 2002. [DOI: 10.1111/j.1440-1797.2002.tb00516.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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McDonald KJ, Cameron AJM, Allen JM, Jardine AG. Expression of Fc alpha/mu receptor by human mesangial cells: a candidate receptor for immune complex deposition in IgA nephropathy. Biochem Biophys Res Commun 2002; 290:438-42. [PMID: 11779189 DOI: 10.1006/bbrc.2001.6218] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
IgA nephropathy is characterized by the deposition of IgA immune complexes in the glomerular mesangium, but the mechanisms responsible for this are not well understood. Human mesangial cells (HMCs) can bind IgA but do not express known IgA receptors. We show here that primary HMCs express mRNA for a novel receptor, the Fc alpha/mu receptor (Fcalpha/muR), and that receptor expression is upregulated by IL-1. We also detected mRNA for a novel receptor variant in HMCs that may encode a soluble form of the receptor. Fcalpha/muR was expressed in a heterologous system which showed that the receptor was approximately 58 kDa in weight and was only minimally N-glycosylated. As predicted from the characteristics of the murine homologue, the expressed human Fcalpha/muR was able to bind IgA and IgM, but not IgG. These results suggest that Fcalpha/muR may be the receptor responsible for mesangial IgA deposition in IgA nephropathy.
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Affiliation(s)
- Kenneth J McDonald
- Renal Unit, Western Infirmary, Dumbarton Road, Glasgow G11 6NT, Scotland, United Kingdom.
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31
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Novak J, Julian BA, Tomana M, Mesteck J. Progress in molecular and genetic studies of IgA nephropathy. J Clin Immunol 2001; 21:310-27. [PMID: 11720004 DOI: 10.1023/a:1012284402054] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Several new findings emerged recently from biochemical, genetic, and molecular studies of patients with IgA nephropathy. It appears that immunoglobulin A1-secreting cells of IgA nephropathy patients produce increased amounts of aberrantly glycosylated IgA1 in which the O-linked glycans in the hinge region are deficient in the content of galactose. The galactose-deficient IgA1 in the circulation is recognized by naturally occurring antibodies with anti-glycan specificity, and immune complexes are formed. These circulating immune complexes escape hepatic degradation and eventually are deposited in the kidney mesangium. Resident mesangial cells bind the IgA-containing immune complexes with the involvement of a novel IgA receptor and become activated. A familial form of IgA nephropathy has been linked to chromosome 6q22-23. Recent progress in molecular analyses of IgA nephropathy thus defines this disease as an autoimmune process with a novel IgA mesangial receptor and certain genetically determined traits.
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Affiliation(s)
- J Novak
- Department of Microbiology, University of Alabama at Birmingham, 35294, USA.
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32
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Pilette C, Ouadrhiri Y, Godding V, Vaerman JP, Sibille Y. Lung mucosal immunity: immunoglobulin-A revisited. Eur Respir J 2001; 18:571-88. [PMID: 11589357 DOI: 10.1183/09031936.01.00228801] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mucosal defence mechanisms are critical in preventing colonization of the respiratory tract by pathogens and penetration of antigens through the epithelial barrier. Recent research has now illustrated the active contribution of the respiratory epithelium to the exclusion of microbes and particles, but also to the control of the inflammatory and immune responses in the airways and in the alveoli. Epithelial cells also mediate the active transport of polymeric immunoglobulin-A from the lamina propria to the airway lumen through the polymeric immunoglobulin receptor. The role of IgA in the defence of mucosal surfaces has now expanded from a limited role of scavenger of exogenous material to a broader protective function with potential applications in immunotherapy. In addition, the recent identification of receptors for IgA on the surface of blood leukocytes and alveolar macrophages provides an additional mechanism of interaction between the cellular and humoral immune systems at the level of the respiratory tract.
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Affiliation(s)
- C Pilette
- Unit of Experimental Medicine, Christian de Duve Institute of Cellular Pathology, University of Louvain, Brussels, Belgium
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33
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Moura IC, Centelles MN, Arcos-Fajardo M, Malheiros DM, Collawn JF, Cooper MD, Monteiro RC. Identification of the transferrin receptor as a novel immunoglobulin (Ig)A1 receptor and its enhanced expression on mesangial cells in IgA nephropathy. J Exp Med 2001; 194:417-25. [PMID: 11514599 PMCID: PMC2193503 DOI: 10.1084/jem.194.4.417] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The biological functions of immunoglobulin (Ig)A antibodies depend primarily on their interaction with cell surface receptors. Four IgA receptors are presently characterized. The FcalphaRI (CD89) expressed by myeloid cells selectively binds IgA1 and IgA2 antibodies, whereas the poly-IgR, Fcalpha/muR, and asialoglycoprotein receptors bind other ligands in addition to IgA. IgA binding by mesangial cells, epithelial cells, and proliferating lymphocytes is also well documented, but the nature of the IgA receptors on these cells remains elusive. A monoclonal antibody (A24) is described here that specifically blocks IgA binding to epithelial and B lymphocyte cell lines. Both the A24 antibody and IgA1 myelomas bind a cell surface protein that is identified as the transferrin receptor (CD71). The transferrin receptor selectively binds IgA1 antibodies, monomeric better than polymeric forms, and the IgA1 binding is inhibitable by transferrin. Transferrin receptor expression is upregulated on cultured mesangial cells as well as on glomerular mesangial cells in patients with IgA nephropathy. The characterization of transferrin receptor as a novel IgA1 receptor on renal mesangial cells suggests its potential involvement in the pathogenesis of IgA nephropathy.
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Affiliation(s)
- Ivan C. Moura
- Institut National de la Santé et de la Recherche Médicale (INSERM) U25, Necker Hospital, Paris 75743 Cédex 15, France
| | - Miguel N. Centelles
- Institut National de la Santé et de la Recherche Médicale (INSERM) U25, Necker Hospital, Paris 75743 Cédex 15, France
| | - Michelle Arcos-Fajardo
- Institut National de la Santé et de la Recherche Médicale (INSERM) U25, Necker Hospital, Paris 75743 Cédex 15, France
| | - Denise M. Malheiros
- Division of Nephrology, University of São Paulo Medical School, São Paulo 01246, Brazil
| | - James F. Collawn
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Max D. Cooper
- The Howard Hughes Medical Institute, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Renato C. Monteiro
- Institut National de la Santé et de la Recherche Médicale (INSERM) U25, Necker Hospital, Paris 75743 Cédex 15, France
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34
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Davin JC, Ten Berge IJ, Weening JJ. What is the difference between IgA nephropathy and Henoch-Schönlein purpura nephritis? Kidney Int 2001; 59:823-34. [PMID: 11231337 DOI: 10.1046/j.1523-1755.2001.059003823.x] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) are considered to be related diseases since both can be encountered consecutively in the same patient, they have been described in twins, and bear identical pathological and biological abnormalities. Apart from the presence of extrarenal clinical signs found only in HSPN, other differences are noticed between the two diseases. The peak age ranges between 15 and 30 years for a diagnosis of IgAN, whereas HSPN is mainly seen in childhood. Nephritic and/or nephrotic syndromes are more often seen at presentation in HSPN. In contrast to IgAN, HSPN has been described in association with hypersensitivity. Endocapillary and extracapillary inflammations as well as fibrin deposits in the glomerulus are more frequent in HSPN. No major biological differences have been found between the two illnesses, except for a larger size of circulating IgA-containing complexes (IgA-CC) and a greater incidence of increased plasma IgE levels in HSPN. As tissue infiltration by leukocytes is a major feature of HSPN vasculitis, a possible role of a more potent activation of the latter cells by IgA-CC and/or circulating chemokines in HSPN should be considered. Further studies are required to elucidate this possible mechanism as well as the role of hypersensitivity in HSPN.
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Affiliation(s)
- J C Davin
- Department of Pediatrics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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35
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Leung JC, Tang SC, Lam MF, Chan TM, Lai KN. Charge-dependent binding of polymeric IgA1 to human mesangial cells in IgA nephropathy. Kidney Int 2001; 59:277-85. [PMID: 11135081 DOI: 10.1046/j.1523-1755.2001.00489.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is characterized by raised serum IgA1 and predominant mesangial IgA1 deposits of polymeric nature. The mechanism of polymeric IgA1 (pIgA1) deposition in the kidney mesangium is poorly understood in IgAN. It has been suggested that increased sialic acid content and anionic charge of the pIgA1 molecules may be operational in the IgA1 deposition in human mesangial cells (HMCs). The present study examined the binding of pIgA1 with different surface charges to HMCs. The binding characteristics of IgA1 to HMCs in the presence of polycation (poly-L-lysine) or polyanion (heparin) were also investigated. METHODS IgA1 was purified in sera from patients with IgAN and from healthy controls by jacalin affinity chromatography. IgA1 was further separated into pIgA1 and monomeric IgA1 (mIgA1) by fast protein liquid chromatography (FPLC). pIgA1 or mIgA1 with different net charges on their surface were resolved by ion exchange chromatography (IEC) with a Mono Q column. The binding characteristics of pIgA1 and mIgA1 to HMCs in the presence or absence of polycation or polyanion were examined by flow cytometry. RESULTS In patients with IgAN, the absolute amount of mIgA1 and pIgA1 is significantly higher than that of healthy controls (P < 0. 001). There was significant increase in binding of pIgA1 from patients with IgAN to HMC and cell lysate. pIgA1 that interacted strongly with the ion exchanger also bound more to HMCs when compared with IgA1 interacted weakly with the ion exchanger (P < 0. 001). The anionic charged pIgA1 from patients was significantly higher than that of healthy controls (P < 0.001). Preincubation with poly-L-lysine increased the binding of pIgA1 to HMCs. The binding of pIgA1 to HMCs was decreased by preincubation with heparin. CONCLUSIONS The binding of IgA to HMCs is charge dependent. Polymeric IgA with the highest net negative charge binds more to HMCs. Preincubation with polyanion decreased the binding of polymeric IgA to HMCs. These results suggest an important role for anionic charge in IgA1 deposition onto the kidney mesangial cells.
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Affiliation(s)
- J C Leung
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
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36
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TOMINO Y, TSUGE T. Role of cytokine mediators in the pathogenesis of IgA nephropathy. Int J Organ Transplant Med 2000. [DOI: 10.1016/s1561-5413(09)60039-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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37
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Launay P, Grossetête B, Arcos-Fajardo M, Gaudin E, Torres SP, Beaudoin L, Patey-Mariaud de Serre N, Lehuen A, Monteiro RC. Fcalpha receptor (CD89) mediates the development of immunoglobulin A (IgA) nephropathy (Berger's disease). Evidence for pathogenic soluble receptor-Iga complexes in patients and CD89 transgenic mice. J Exp Med 2000; 191:1999-2009. [PMID: 10839814 PMCID: PMC2213528 DOI: 10.1084/jem.191.11.1999] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The pathogenesis of immunoglobulin A (IgA) nephropathy (IgAN), the most prevalent form of glomerulonephritis worldwide, involves circulating macromolecular IgA1 complexes. However, the molecular mechanism(s) of the disease remain poorly understood. We report here the presence of circulating soluble FcalphaR (CD89)-IgA complexes in patients with IgAN. Soluble CD89 was identified as a glycoprotein with a 24-kD backbone that corresponds to the expected size of CD89 extracellular domains. To demonstrate their pathogenic role, we generated transgenic (Tg) mice expressing human CD89 on macrophage/monocytes, as no CD89 homologue is found in mice. These mice spontaneously developed massive mesangial IgA deposition, glomerular and interstitial macrophage infiltration, mesangial matrix expansion, hematuria, and mild proteinuria. The molecular mechanism was shown to involve soluble CD89 released after interaction with IgA. This release was independent of CD89 association with the FcRgamma chain. The disease was induced in recombination activating gene (RAG)2(-/-) mice by injection of serum from Tg mice, and in severe combined immunodeficiency (SCID)-Tg mice by injection of patients' IgA. Depletion of soluble CD89 from serum abolished this effect. These results reveal the key role of soluble CD89 in the pathogenesis of IgAN and provide an in vivo model that will be useful for developing new treatments.
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Affiliation(s)
- Pierre Launay
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Béatrice Grossetête
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Michelle Arcos-Fajardo
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Emmanuelle Gaudin
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Sonia P. Torres
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Lucie Beaudoin
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | | | - Agnès Lehuen
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
| | - Renato C. Monteiro
- Institut National de la Santé et de la Recherche Médicale U25, Necker Hospital, Paris 75743, France
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38
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Kitamura T, Garofalo RP, Kamijo A, Hammond DK, Oka JA, Caflisch CR, Shenoy M, Casola A, Weigel PH, Goldblum RM. Human intestinal epithelial cells express a novel receptor for IgA. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5029-34. [PMID: 10799857 DOI: 10.4049/jimmunol.164.10.5029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Binding and transport of polymeric Igs (pIgA and IgM) across epithelia is mediated by the polymeric Ig receptor (pIgR), which is expressed on the basolateral surface of secretory epithelial cells. Although an Fc receptor for IgA (FcalphaR) has been identified on myeloid cells and some cultured mesangial cells, the expression of an FcalphaR on epithelial cells has not been described. In this study, binding of IgA to a human epithelial line, HT-29/19A, with features of differentiated colonic epithelial cells, was examined. Radiolabeled monomeric IgA (mIgA) showed a dose-dependent, saturable, and cation-independent binding to confluent monolayers of HT-29/19A cells. Excess of unlabeled mIgA, but not IgG or IgM, competed for the mIgA binding, indicating that the binding was IgA isotype-specific and was not mediated by the pIgR. The lack of competition by asialoorosomucoid and the lack of requirement for divalent cations excluded the possibility that IgA binding to HT-29/19A cells was due to the asialoglycoprotein receptor or beta-1, 4-galactosyltransferase, previously described on HT-29 cells. Moreover, the FcalphaR (CD89) protein and message were undetectable in HT-29/19A cells. FACS analysis of IgA binding demonstrated two discrete populations of HT-29/19 cells, which bound different amounts of mIgA. IgA binding to other colon carcinoma cell lines was also demonstrated by FACS analysis, suggesting that an IgA receptor, distinct from the pIgR, asialoglycoprotein receptor, galactosyltransferase, and CD89 is constitutively expressed on cultured human enterocytes. The function of this novel IgA receptor in mucosal immunity remains to be elucidated.
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Affiliation(s)
- T Kitamura
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX 77555, USA
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39
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Barratt J, Greer MR, Pawluczyk IZ, Allen AC, Bailey EM, Buck KS, Feehally J. Identification of a novel Fcalpha receptor expressed by human mesangial cells. Kidney Int 2000; 57:1936-48. [PMID: 10792612 DOI: 10.1046/j.1523-1755.2000.00043.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is characterized by mesangial deposits of polymeric IgA (pIgA). The pathological consequences of IgA deposition are believed to center on direct interaction between IgA and the glomerular mesangial cell (MC). We have characterized a novel mesangial receptor that recognizes the Fc portion of IgA. METHODS Five primary MC cultures were evaluated for IgA binding by flow cytometry, and specificity of binding was determined by competitive inhibition. Relative affinities of the receptor for all IgA isoforms were also determined, and binding of pIgA1 was compared to monomer. The identified Fc receptor was then compared with CD89, hitherto the only other Fcalpha receptor reported. CD89 protein and mRNA expression were detected by conventional and intracellular flow cytometry, sequencing of reverse transcription-polymerase chain reaction (RT-PCR) products, and Northern blotting. RESULTS All MCs constitutively expressed a receptor that bound IgA in an Fcalpha-dependent fashion. The receptor recognized secretory and serum IgA1 and IgA2 equally, but pIgA bound with much greater affinity than monomer. At no time were we able to detect CD89 synthesis, although three novel CD89-related mRNA transcripts were identified by RT-PCR. CONCLUSIONS We have clearly demonstrated that MCs consistently express an FcalphaR distinct from the myeloid FcalphaR CD89. This novel receptor binds pIgA with high affinity and may therefore mediate the mesangial injury that follows IgA deposition in IgAN. While immunogenically distinct, the mesangial Fcalpha receptor may share some molecular homology with CD89, as mRNA transcripts with partial identity to CD89 were found in all five MC cultures.
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Affiliation(s)
- J Barratt
- Department of Nephrology, Leicester General Hospital, Leicester, England, United Kingdom.
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40
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Leung JCK, Tsang AWL, Chan DTM, Lai KN. Absence of CD89, polymeric immunoglobulin receptor, and asialoglycoprotein receptor on human mesangial cells. J Am Soc Nephrol 2000; 11:241-249. [PMID: 10665931 DOI: 10.1681/asn.v112241] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
IgA nephropathy (IgAN) is characterized by raised serum IgA and predominant mesangial IgA deposits of polymeric nature. The expression of IgA receptor molecules in white blood cells and glomerular mesangial cells has recently attracted much attention in relation to the uptake of IgA by these cells. This study investigates the expression of IgA Fc receptor (Fc alphaR1 or CD89), asialoglycoprotein receptor (ASGPR), and polymeric Ig receptor (pIgR) in cultured glomerular mesangial cells. Using a sensitive nested reverse transcription-PCR, mRNA encoding for Fc alphaR1, pIgR, or the H2 chain of ASGPR was not demonstrated on human mesangial cells. U937, HepG2, and HT29 cell lines, used as positive controls, strongly expressed the Fc alphaR1, ASGPR, and pIgR mRNA, respectively, under similar experimental conditions. Flow cytometry also demonstrated the presence of surface proteins for Fc alphaR1, ASGPR, and pIgR on the respective control cell lines but not on human mesangial cells. Expression of Fc alphaR1 mRNA on cultured U937 cells was upregulated by tumor necrosis factor-alpha. However, tumor necrosis factor-alpha, interleukin-1beta, or transforming growth factor-beta failed to induce the expression of Fc alphaR1 on human mesangial cells. Human serum IgA or secretory IgA bound to human mesangial cells, HepG2, or the U937 cell line in a dose-dependent manner. The binding of purified IgA to human mesangial cells was not blocked by preincubation with human IgG, IgM, orosomucoid, asialo-orosomucoid, anti-CD89 antibody (My43), or anti-secretory component antibody. The present study concluded that there was an absence of Fc alphaR1, ASGPR, or pIgR on human mesangial cells. These findings suggest that the predominant binding of human IgA to human mesangial cells is mediated by other mechanisms.
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MESH Headings
- Antibodies/pharmacology
- Antigens, CD/genetics
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Asialoglycoprotein Receptor
- Cell Line
- Cytokines/pharmacology
- Glomerular Mesangium/cytology
- Glomerular Mesangium/metabolism
- Humans
- Immunoglobulin A/metabolism
- Immunoglobulin A/pharmacology
- Immunoglobulin A, Secretory/pharmacology
- Immunoglobulin G/pharmacology
- RNA, Messenger/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Fc/genetics
- Receptors, Fc/immunology
- Receptors, Fc/metabolism
- Receptors, Polymeric Immunoglobulin/genetics
- Receptors, Polymeric Immunoglobulin/metabolism
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Affiliation(s)
- Joseph C K Leung
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
| | - Anita W L Tsang
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
| | - Daniel T M Chan
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
| | - Kar Neng Lai
- Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong
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41
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Montenegro V, Monteiro RC. Elevation of serum IgA in spondyloarthropathies and IgA nephropathy and its pathogenic role. Curr Opin Rheumatol 1999; 11:265-72. [PMID: 10411380 DOI: 10.1097/00002281-199907000-00007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ankylosing spondylitis and IgA nephropathy share some immunologic features, eg, elevated serum IgA and IgA-immune complex levels. These entities are frequently found as being associated. IgA and IgA immune complex catabolism involves asialoglycoprotein receptors and specific IgA Fc receptors (FcalphaR or CD89) on tissue and blood cells. Recent studies revealed impaired CD89 expression in both diseases. These abnormalities, which are associated with receptor saturation, might generate the increase in serum IgA and IgA immune complex levels by either altered recycling or failure of degradation. This article reviews the literature on IgA abnormalities and discusses the potential role of FcalphaR in IgA nephropathy and AS and the consequences of its similar defect in the two diseases.
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Affiliation(s)
- V Montenegro
- Division of Rheumatology, University of São Paulo, Brazil
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