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Reily C, Moldoveanu Z, Pramparo T, Hall S, Huang ZQ, Rice T, Novak L, Komers R, Jenkinson CP, Novak J. Sparsentan ameliorates glomerular hypercellularity and inflammatory-gene networks induced by IgA1-IgG immune complexes in a mouse model of IgA nephropathy. Am J Physiol Renal Physiol 2024; 326:F862-F875. [PMID: 38511222 DOI: 10.1152/ajprenal.00253.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 02/07/2024] [Accepted: 03/02/2024] [Indexed: 03/22/2024] Open
Abstract
IgA nephropathy (IgAN) is characterized by glomerular deposition of immune complexes (ICs) consisting of IgA1 with O-glycans deficient in galactose (Gd-IgA1) and Gd-IgA1-specific IgG autoantibodies. These ICs induce kidney injury, and in the absence of disease-specific therapy, up to 40% of patients with IgAN progress to kidney failure. IgA1 with its clustered O-glycans is unique to humans, which hampered development of small-animal models of IgAN. Here, we used a model wherein engineered ICs (EICs) formed from human Gd-IgA1 and recombinant human IgG autoantibody are injected into nude mice to induce glomerular injury mimicking human IgAN. In this model, we assessed the protective effects of sparsentan, a single-molecule dual endothelin angiotensin receptor antagonist (DEARA) versus vehicle on EIC-induced glomerular proliferation and dysregulation of gene expression in the kidney. Oral administration of sparsentan (60 or 120 mg/kg daily) to mice intravenously injected with EIC attenuated the EIC-induced glomerular hypercellularity. Furthermore, analysis of changes in the whole kidney transcriptome revealed that key inflammatory and proliferative biological genes and pathways that are upregulated in this EIC model of IgAN were markedly reduced by sparsentan, including complement genes, integrin components, members of the mitogen-activated protein kinase family, and Fc receptor elements. Partial overlap between mouse and human differentially expressed genes in IgAN further supported the translational aspect of the immune and inflammatory components from our transcriptional findings. In conclusion, our data indicate that in the mouse model of IgAN, sparsentan targets immune and inflammatory processes leading to protection from mesangial hypercellularity.NEW & NOTEWORTHY The mechanisms by which deposited IgA1 immune complexes cause kidney injury during early phases of IgA nephropathy are poorly understood. We used an animal model we recently developed that involves IgA1-IgG immune complex injections and determined pathways related to the induced mesangioproliferative changes. Treatment with sparsentan, a dual inhibitor of endothelin type A and angiotensin II type 1 receptors, ameliorated the induced mesangioproliferative changes and the associated alterations in the expression of inflammatory genes and networks.
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Affiliation(s)
- Colin Reily
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Zina Moldoveanu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Tiziano Pramparo
- Travere Therapeutics Incorporated, San Diego, California, United States
| | - Stacy Hall
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Zhi-Qiang Huang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Terri Rice
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Lea Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Radko Komers
- Travere Therapeutics Incorporated, San Diego, California, United States
| | - Celia P Jenkinson
- Travere Therapeutics Incorporated, San Diego, California, United States
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States
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2
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Dybiec J, Frąk W, Kućmierz J, Tokarek J, Wojtasińska A, Młynarska E, Rysz J, Franczyk B. Liquid Biopsy: A New Avenue for the Diagnosis of Kidney Disease: Diabetic Kidney Disease, Renal Cancer, and IgA Nephropathy. Genes (Basel) 2024; 15:78. [PMID: 38254967 PMCID: PMC10815875 DOI: 10.3390/genes15010078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
Kidney diseases are some of the most common healthcare problems. As the population of elderly individuals with concurrent health conditions continues to rise, there will be a heightened occurrence of these diseases. Due to the renal condition being one of the longevity predictors, early diagnosis of kidney dysfunction plays a crucial role. Currently, prevalent diagnostic tools include laboratory tests and kidney tissue biopsies. New technologies, particularly liquid biopsy and new detection biomarkers, hold promise for diagnosing kidney disorders. The aim of this review is to present modern diagnostic methods for kidney diseases. The paper focuses on the advances in diagnosing three common renal disorders: diabetic kidney disease, renal cancer, and immunoglobulin A nephropathy. We highlight the significance of liquid biopsy and epigenetic changes, such as DNA methylation, microRNA, piRNAs, and lncRNAs expression, or single-cell transcriptome sequencing in the assessment of kidney diseases. This review underscores the importance of early diagnosis for the effective management of kidney diseases and investigates liquid biopsy as a promising approach.
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Affiliation(s)
- Jill Dybiec
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Weronika Frąk
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Joanna Kućmierz
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Julita Tokarek
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Armanda Wojtasińska
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Ewelina Młynarska
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Jacek Rysz
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Beata Franczyk
- Department of Nephrocardiology, Medical University of Lodz, ul. Zeromskiego 113, 90-549 Lodz, Poland
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3
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Stamellou E, Seikrit C, Tang SCW, Boor P, Tesař V, Floege J, Barratt J, Kramann R. IgA nephropathy. Nat Rev Dis Primers 2023; 9:67. [PMID: 38036542 DOI: 10.1038/s41572-023-00476-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/26/2023] [Indexed: 12/02/2023]
Abstract
IgA nephropathy (IgAN), the most prevalent primary glomerulonephritis worldwide, carries a considerable lifetime risk of kidney failure. Clinical manifestations of IgAN vary from asymptomatic with microscopic or intermittent macroscopic haematuria and stable kidney function to rapidly progressive glomerulonephritis. IgAN has been proposed to develop through a 'four-hit' process, commencing with overproduction and increased systemic presence of poorly O-glycosylated galactose-deficient IgA1 (Gd-IgA1), followed by recognition of Gd-IgA1 by antiglycan autoantibodies, aggregation of Gd-IgA1 and formation of polymeric IgA1 immune complexes and, lastly, deposition of these immune complexes in the glomerular mesangium, leading to kidney inflammation and scarring. IgAN can only be diagnosed by kidney biopsy. Extensive, optimized supportive care is the mainstay of therapy for patients with IgAN. For those at high risk of disease progression, the 2021 KDIGO Clinical Practice Guideline suggests considering a 6-month course of systemic corticosteroid therapy; however, the efficacy of systemic steroid treatment is under debate and serious adverse effects are common. Advances in understanding the pathophysiology of IgAN have led to clinical trials of novel targeted therapies with acceptable safety profiles, including SGLT2 inhibitors, endothelin receptor blockers, targeted-release budesonide, B cell proliferation and differentiation inhibitors, as well as blockade of complement components.
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Affiliation(s)
- Eleni Stamellou
- Department of Nephrology, School of Medicine, University of Ioannina, Ioannina, Greece
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Claudia Seikrit
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Sydney C W Tang
- Division of Nephrology, Department of Medicine, University of Hong Kong, Hong Kong, China
| | - Peter Boor
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
- Department of Pathology, RWTH Aachen University, Aachen, Germany
| | - Vladimir Tesař
- Department of Nephrology, 1st Faculty of Medicine and General University Hospital, Charles University, Prague, Czech Republic
| | - Jürgen Floege
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Rafael Kramann
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany.
- Department of Internal Medicine, Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, Netherlands.
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Rajasekaran A, Green TJ, Renfrow MB, Julian BA, Novak J, Rizk DV. Current Understanding of Complement Proteins as Therapeutic Targets for the Treatment of Immunoglobulin A Nephropathy. Drugs 2023; 83:1475-1499. [PMID: 37747686 PMCID: PMC10807511 DOI: 10.1007/s40265-023-01940-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a frequent cause of kidney failure. Currently, the diagnosis necessitates a kidney biopsy, with routine immunofluorescence microscopy revealing IgA as the dominant or co-dominant immunoglobulin in the glomerular immuno-deposits, often with IgG and sometimes IgM or both. Complement protein C3 is observed in most cases. IgAN leads to kidney failure in 20-40% of patients within 20 years of diagnosis and reduces average life expectancy by about 10 years. There is increasing clinical, biochemical, and genetic evidence that the complement system plays a paramount role in the pathogenesis of IgAN. The presence of C3 in the kidney immuno-deposits differentiates the diagnosis of IgAN from subclinical glomerular mesangial IgA deposition. Markers of complement activation via the lectin and alternative pathways in kidney-biopsy specimens are associated with disease activity and are predictive of poor outcome. Levels of select complement proteins in the circulation have also been assessed in patients with IgAN and found to be of prognostic value. Ongoing genetic studies have identified at least 30 loci associated with IgAN. Genes within some of these loci encode complement-system regulating proteins that can interact with immune complexes. The growing appreciation for the central role of complement components in IgAN pathogenesis highlighted these pathways as potential treatment targets and sparked great interest in pharmacological agents targeting the complement cascade for the treatment of IgAN, as evidenced by the plethora of ongoing clinical trials.
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Affiliation(s)
- Arun Rajasekaran
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Todd J Green
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Bruce A Julian
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dana V Rizk
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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5
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Liu Y, Gong Y, Xu G. The role of mononuclear phagocyte system in IgA nephropathy: pathogenesis and prognosis. Front Immunol 2023; 14:1192941. [PMID: 37529043 PMCID: PMC10390225 DOI: 10.3389/fimmu.2023.1192941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/12/2023] [Indexed: 08/03/2023] Open
Abstract
Although the "multiple hits" theory is a widely accepted pathogenesis in IgA nephropathy (IgAN), increasing evidence suggests that the mononuclear/macrophage system plays important roles in the progression of IgAN; however, the exact mechanism is unclear. In the present study, we explored 1,067 patients in 15 studies and found that the number of macrophages per glomerulus was positively related with the degree of hematuria, and the macrophages in the glomeruli were mainly related to mesangial proliferation (M) in renal biopsy. In the tubulointerstitium, macrophages were significantly paralleled to tubulointerstitial α-SMA and NF-kB expression, tubulointerstitial lesion, tubule atrophy/interstitial fibrosis (T), and segmental glomerulosclerosis (S). In the glomeruli and tubulointerstitium, M1 accounted for 85.41% in the M classification according to the Oxford MEST-C, while in the blood, M1 accounted for 100%, and the patients with low CD89+ monocyte mean fluorescence intensity displayed more severe pathological characteristics (S1 and T1-2) and clinical symptoms. M1 (CD80+) macrophages were associated with proinflammation in the acute phase; however, M2 (CD163+) macrophages participated in tissue repair and remodeling, which correlated with chronic inflammation. In the glomeruli, M2 macrophages activated glomerular matrix expansion by secreting cytokines such as IL-10 and tumor necrosis factor-β (TGF-β), and M0 (CD68+) macrophages stimulated glomerular hypercellularity. In the tubulointerstitium, M2 macrophages played pivotal roles in renal fibrosis and sclerosis. It is assumed that macrophages acted as antigen-presenting cells to activate T cells and released diverse cytokines to stimulate an inflammatory response. Macrophages infiltrating glomeruli destroy the integrity of podocytes through the mesangio-podocytic-tubular crosstalk as well as the injury of the tubule.
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Affiliation(s)
- Yiwen Liu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, Nanchang, Jiangxi, China
| | - Yan Gong
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Gaosi Xu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
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6
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Tamura H. IgA nephropathy associated with Crohn's disease. World J Methodol 2023; 13:67-78. [PMID: 37456980 PMCID: PMC10348078 DOI: 10.5662/wjm.v13.i3.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/16/2023] [Accepted: 05/12/2023] [Indexed: 06/20/2023] Open
Abstract
The relationship between IgA nephropathy (IgAN) and Crohn’s disease was reported. IgAN is the most common primary glomerulonephritis and one of the leading causes of chronic kidney disease and end-stage renal failure, and up to 50% of cases progressed to end-stage renal disease within 25 years after IgAN diagnosis. However, specific and effective therapeutic strategies are still lacking. In this review, we discuss the possibility of the mechanism involved in IgAN associated with Crohn’s disease based on the findings of basic and clinical studies. Although the etiology of IgAN associated with Crohn’s disease is not permanent and various factors are thought to be involved, the stabilization of the disease condition of Crohn’s disease is believed to help treat IgAN.
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Affiliation(s)
- Hiroshi Tamura
- Department of Pediatrics, Kumamoto University, Kumamoto 8608556, Japan
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7
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Barratt J, Lafayette RA, Zhang H, Tesar V, Rovin BH, Tumlin JA, Reich HN, Floege J. IgA Nephropathy: the Lectin Pathway and Implications for Targeted Therapy. Kidney Int 2023:S0085-2538(23)00395-2. [PMID: 37263354 DOI: 10.1016/j.kint.2023.04.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/30/2023] [Accepted: 04/14/2023] [Indexed: 06/03/2023]
Abstract
Many patients with IgA nephropathy (IgAN) progress to end-stage kidney disease even with optimal supportive care. An improved understanding of the pathophysiology of IgAN in recent years has led to the investigation of targeted therapies with acceptable tolerability that may address the underlying causes of IgAN or the pathogenesis of kidney injury. The complement system - particularly the lectin and alternative pathways of complement - have emerged as key mediators of kidney injury in IgAN and possible targets for investigational therapy. This review will focus on the lectin pathway. Examination of kidney biopsies has consistently shown glomerular deposition of mannan-binding lectin (one of six pattern-recognition molecules that activate the lectin pathway) together with IgA1 in up to 50% of patients with IgAN. Glomerular deposition of pattern-recognition molecules for the lectin pathway is associated with more severe glomerular damage and more severe proteinuria and hematuria. Emerging research suggests that the lectin pathway may also contribute to tubulointerstitial fibrosis in IgAN, and that collectin-11 is a key mediator of this association. This review summarizes the growing scientific and clinical evidence supporting the role of the lectin pathway in IgAN and examines the possible therapeutic role of lectin pathway inhibition for these patients.
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Affiliation(s)
| | | | - Hong Zhang
- Peking University Institute of Nephrology, Beijing, China
| | - Vladimir Tesar
- Charles University and General University Hospital, Prague, Czech Republic
| | - Brad H Rovin
- The Ohio State University Wexner Medical Center, Columbus OH, USA
| | | | - Heather N Reich
- University of Toronto and University Health Network, Toronto ON, Canada
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8
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Mucha K, Pac M, Pączek L. Omics are Getting Us Closer to Understanding IgA Nephropathy. Arch Immunol Ther Exp (Warsz) 2023; 71:12. [PMID: 37060455 PMCID: PMC10105675 DOI: 10.1007/s00005-023-00677-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 03/02/2023] [Indexed: 04/16/2023]
Abstract
During the last decade, thanks to omics technologies, new light has been shed on the pathogenesis of many diseases. Genomics, epigenomics, transcriptomics, and proteomics have helped to provide a better understanding of the origin and heterogeneity of several diseases. However, the risk factors for most autoimmune diseases remain unknown. The successes and pitfalls of omics have also been observed in nephrology, including immunoglobulin A nephropathy (IgAN), the most common form of glomerulonephritis and a principal cause of end-stage renal disease worldwide. Unfortunately, the immense progress in basic research has not yet been followed by the satisfactory development of a targeted treatment. Although, most omics studies describe changes in the immune system, there is still insufficient data to apply their results in the constantly evolving multi-hit pathogenesis model and thus do to provide a complete picture of the disease. Here, we describe recent findings regarding the pathophysiology of IgAN and link omics studies with immune system dysregulation. This review provides insights into specific IgAN markers, which may lead to the identification of potential targets for personalised treatment in the future.
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Affiliation(s)
- Krzysztof Mucha
- Department of Immunology, Transplantology and Internal Diseases, Medical University of Warsaw, Warsaw, Poland.
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
| | - Michał Pac
- Department of Immunology, Transplantology and Internal Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Leszek Pączek
- Department of Immunology, Transplantology and Internal Diseases, Medical University of Warsaw, Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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9
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The significance of galactose-deficient immunoglobulin A1 staining in kidney diseases with IgA deposition. Int Urol Nephrol 2023:10.1007/s11255-023-03512-5. [PMID: 36849627 DOI: 10.1007/s11255-023-03512-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 01/09/2023] [Indexed: 03/01/2023]
Abstract
BACKGROUND This study investigated the significance of galactose-deficient immunoglobulin A1 staining in kidney diseases with IgA deposition. METHODS A total of 120 patients with IgA-dominant deposition in kidney tissues were enrolled and divided into four groups: primary IgA nephropathy (PIgAN), secondary IgA nephropathy (SIgAN), monotypic IgA nephropathy (MIgAN), and IgA variant monoclonal gammopathy of renal significance (IgA-MGRS). KM55 (the antibody of galactose-deficient immunoglobulin A1), IgA subtypes, and complement pathway factors (properdin, C4d, and C1q) were detected through immunofluorescence or immunohistochemistry analysis. RESULTS KM55 and IgA double staining showed colocalization within glomeruli in all cases except for IgA-MGRS, which showed negative or weak staining of KM55 but strong staining of IgA. The PIgAN group showed the highest intensity of KM55 and KM55/IgA ratio, while these values in the IgA-MGRS group were the lowest (P < 0.01). A KM55/IgA quantified ratio of 0.78 was the optimal cut-off value to distinguish PIgAN from SIgAN, whereas a cut-off value of 0.21 was optimal to distinguish between MIgAN and IgA-MGRS. The clinicopathological characteristics showed significant differences as the groups were divided by diseases with optimal cut-off values, and these differences corresponded to the pathogenesis of each disease entity. CONCLUSIONS PIgAN, SIgAN, and MIgAN are caused by the deposition of abnormally glycosylated IgA1 whereas IgA-MGRS is not. The KM55/IgA quantified ratio is valuable in distinguishing PIgAN from SIgAN, as well as MIgAN from IgA-MGRS.
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10
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Si M, Li L, Fang M, Ye Z, Zhang XC, Yang W, Nie L, Yu X. Anomalous kinetics of galactose-deficient IgA incurring nephropathy revealed by cross-scale optical imaging. Kidney Int 2023; 103:320-330. [PMID: 36341730 DOI: 10.1016/j.kint.2022.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/06/2022]
Abstract
IgA nephropathy (IgAN) is the most common glomerulonephritis, characterized by the presence of predominant IgA deposits in the mesangium. Deposition of pathogenic IgA in kidney tissue is a fundamental initiating process that has not been fully studied. Here, we employed optical imaging to directly visualize kidney deposition of IgA with optimized spatial and temporal resolution in BALB/c nude mice. Real-time fluorescence imaging revealed that IgA isolated from patients with IgAN preferentially accumulated in the kidneys, compared with IgA purified from healthy individuals. There was no difference in the distribution of either IgA preparation by the liver. Photoacoustic computed tomography dynamically demonstrated and quantified the enhanced retention of pathological IgA in the kidney cortex. Photoacoustic microscopy tracked IgA deposition in the glomeruli with a resolution down to three microns in a mouse model. Notably, longitudinal fluorescent imaging revealed that galactose-deficient IgA (Gd-IgA), which was elevated in the circulation of patients with IgAN, persisted in the kidney for longer than two weeks, and stable deposition of Gd-IgA induced kidney impairment, including albuminuria and mesangial proliferation. Thus, our study highlights that the aberrant kidney depositional kinetics of Gd-IgA is involved in the pathogenesis of IgAN. Hence, cross-scale optical imaging has potential applications in assessing immune-mediated kidney diseases and uncovering underlying mechanisms of disease.
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Affiliation(s)
- Meijun Si
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Lanqing Li
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Mengting Fang
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhiming Ye
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xu-Chao Zhang
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wei Yang
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Liming Nie
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xueqing Yu
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
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11
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Mestecky J, Julian BA, Raska M. IgA Nephropathy: Pleiotropic impact of Epstein-Barr virus infection on immunopathogenesis and racial incidence of the disease. Front Immunol 2023; 14:1085922. [PMID: 36865536 PMCID: PMC9973316 DOI: 10.3389/fimmu.2023.1085922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/25/2023] [Indexed: 02/09/2023] Open
Abstract
IgA nephropathy (IgAN) is an autoimmune disease in which poorly galactosylated IgA1 is the antigen recognized by naturally occurring anti-glycan antibodies, leading to formation of nephritogenic circulating immune complexes. Incidence of IgAN displays geographical and racial disparity: common in Europe, North America, Australia, and east Asia, uncommon in African Americans, many Asian and South American countries, Australian Aborigines, and rare in central Africa. In analyses of sera and cells from White IgAN patients, healthy controls, and African Americans, IgAN patients exhibited substantial enrichment for IgA-expressing B cells infected with Epstein-Barr virus (EBV), leading to enhanced production of poorly galactosylated IgA1. Disparities in incidence of IgAN may reflect a previously disregarded difference in the maturation of the IgA system as related to the timing of EBV infection. Compared with populations with higher incidences of IgAN, African Americans, African Blacks, and Australian Aborigines are more frequently infected with EBV during the first 1-2 years of life at the time of naturally occurring IgA deficiency when IgA cells are less numerous than in late childhood or adolescence. Therefore, in very young children EBV enters "non-IgA" cells. Ensuing immune responses prevent infection of IgA B cells during later exposure to EBV at older ages. Our data implicate EBV-infected cells as the source of poorly galactosylated IgA1 in circulating immune complexes and glomerular deposits in patients with IgAN. Thus, temporal differences in EBV primo-infection as related to naturally delayed maturation of the IgA system may contribute to geographic and racial variations in incidence of IgAN.
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Affiliation(s)
- Jiri Mestecky
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Laboratory of Cellular and Molecular Immunology Institute of Microbiology, Czech Academy of Sciences, Prague, Czechia.,Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bruce A Julian
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Milan Raska
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czechia
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12
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Ohyama Y, Yamaguchi H, Ogata S, Chiurlia S, Cox SN, Kouri NM, Stangou MJ, Nakajima K, Hayashi H, Inaguma D, Hasegawa M, Yuzawa Y, Tsuboi N, Renfrow MB, Novak J, Papagianni AA, Schena FP, Takahashi K. Racial heterogeneity of IgA1 hinge-region O-glycoforms in patients with IgA nephropathy. iScience 2022; 25:105223. [PMID: 36277451 PMCID: PMC9583103 DOI: 10.1016/j.isci.2022.105223] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/22/2022] [Accepted: 09/23/2022] [Indexed: 11/23/2022] Open
Abstract
Galactose (Gal)-deficient IgA1 (Gd-IgA1) is involved in IgA nephropathy (IgAN) pathogenesis. To reflect racial differences in clinical characteristics, we assessed disease- and race-specific heterogeneity in the O-glycosylation of the IgA1 hinge region (HR). We determined serum Gd-IgA1 levels in Caucasians (healthy controls [HCs], n = 31; IgAN patients, n = 63) and Asians (HCs, n = 20; IgAN patients, n = 60) and analyzed profiles of serum IgA1 HR O-glycoforms. Elevated serum Gd-IgA1 levels and reduced number of Gal residues per HR were observed in Caucasians. Reduced number of N-acetylgalactosamine (GalNAc) residues per HR and elevated relative abundance of IgA1 with three HR O-glycans were common features in IgAN patients; these features were associated with elevated blood pressure and reduced renal function. We speculate that the mechanisms underlying the reduced GalNAc content in IgA1 HR may be relevant to IgAN pathogenesis.
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Affiliation(s)
- Yukako Ohyama
- Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Hisateru Yamaguchi
- Department of Nursing, Yokkaichi Nursing and Medical Care University, Yokkaichi, Mie 512-8045, Japan
| | - Soshiro Ogata
- Preventive Medicine and Epidemiology, National Cerebral and Cardiovascular Center, Suita, Osaka 564-8565, Japan
| | - Samantha Chiurlia
- University of Bari and Schena Foundation, Valenzano, Bari 70010, Italy
| | - Sharon N. Cox
- University of Bari and Schena Foundation, Valenzano, Bari 70010, Italy
| | - Nikoletta-Maria Kouri
- Department of Nephrology, Aristotle University of Thessaloniki, Thessaloniki, 54642, Greece
| | - Maria J. Stangou
- Department of Nephrology, Aristotle University of Thessaloniki, Thessaloniki, 54642, Greece
| | - Kazuki Nakajima
- Institute for Glyco-core Research, Gifu University, Gifu, Gifu 501-1193, Japan
| | - Hiroki Hayashi
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Daijo Inaguma
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Midori Hasegawa
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Yukio Yuzawa
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Naotake Tsuboi
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Matthew B. Renfrow
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jan Novak
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | | | - Kazuo Takahashi
- Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
- Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
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13
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Harraka P, Wightman T, Akom S, Sandhu K, Colville D, Catran A, Langsford D, Pianta T, Barit D, Ierino F, Skene A, Mack H, Savige J. Increased retinal drusen in IgA glomerulonephritis are further evidence for complement activation in disease pathogenesis. Sci Rep 2022; 12:18301. [PMID: 36316518 PMCID: PMC9622730 DOI: 10.1038/s41598-022-21386-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 09/27/2022] [Indexed: 12/31/2022] Open
Abstract
Drusen are retinal deposits comprising cell debris, immune material and complement that are characteristic of macular degeneration but also found in glomerulonephritis. This was a pilot cross-sectional study to determine how often drusen occurred in IgA glomerulonephritis and their clinical significance. Study participants underwent non-mydriatic retinal photography, and their deidentified retinal images were examined for drusen by two trained graders, who compared central drusen counts, counts ≥ 10 and drusen size with those of matched controls. The cohort comprised 122 individuals with IgA glomerulonephritis including 89 males (73%), 49 individuals (40%) of East Asian or Southern European ancestry, with an overall median age of 54 years (34-64), and median disease duration of 9 years (4-17). Thirty-nine (33%) had an eGFR < 60 ml/min/1.73 m2 and 72 had previously reached kidney failure (61%). Overall mean drusen counts were higher in IgA glomerulonephritis (9 ± 27) than controls (2 ± 7, p < 0.001). Central counts ≥ 10 were also more common (OR = 3.31 (1.42-7.73, p = 0.006), and were associated with longer disease duration (p = 0.03) but not kidney failure (p = 0.31). Larger drusen were associated with more mesangial IgA staining (p = 0.004). Increased drusen counts were also present in IgA glomerulonephritis secondary to Crohn's disease but not with Henoch-Schonlein purpura. The finding of retinal drusen in IgA glomerulonephritis is consistent with complement activation and represents a model for better understanding glomerular immune deposition and a supporting argument for treatment with anti-complement therapies.
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Affiliation(s)
- P. Harraka
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Tony Wightman
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Sarah Akom
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Kieran Sandhu
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Deb Colville
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Andrew Catran
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - David Langsford
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Timothy Pianta
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - David Barit
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Frank Ierino
- grid.1008.90000 0001 2179 088XDepartment of Nephrology, Austin Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Alison Skene
- grid.1008.90000 0001 2179 088XDepartment of Pathology, Austin Health, The University of Melbourne, Parkville, VIC 3050 Australia
| | - Heather Mack
- grid.410670.40000 0004 0625 8539The University of Melbourne Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002 Australia
| | - Judy Savige
- grid.1008.90000 0001 2179 088XDepartment of Medicine, Northern Health, The University of Melbourne, Parkville, VIC 3050 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medicine, Melbourne Health, The University of Melbourne, Parkville, VIC 3050 Australia
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14
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Matsumoto Y, Aryal RP, Heimburg-Molinaro J, Park SS, Wever WJ, Lehoux S, Stavenhagen K, van Wijk JAE, Van Die I, Chapman AB, Chaikof EL, Cummings RD. Identification and characterization of circulating immune complexes in IgA nephropathy. SCIENCE ADVANCES 2022; 8:eabm8783. [PMID: 36306365 PMCID: PMC9616497 DOI: 10.1126/sciadv.abm8783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 09/12/2022] [Indexed: 05/14/2023]
Abstract
The underlying pathology of immunoglobulin A (IgA) nephropathy (IgAN), the most common glomerulonephritis worldwide, is driven by the deposition of immune complexes containing galactose-deficient IgA1 [Tn(+)IgA1] in the glomerular mesangium. Here, we report that novel anti-Tn circulating immune complexes (anti-Tn CICs) contain predominantly IgM, representing large macromolecular complexes of ~1.2 megadaltons to several megadalton sizes together with Tn(+)IgA1 and some IgG. These complexes are significantly elevated in sera of patients with IgAN, which contains higher levels of complement C3, compared to healthy individuals. Anti-Tn CICs are bioactive and induce specific proliferation of human renal mesangial cells. We found that these anti-Tn CICs can be dissociated with small glycomimetic compounds, which mimic the Tn antigen of Tn(+)IgA1, releasing IgA1 from anti-Tn CICs. This glycomimetic compound can also significantly inhibit the proliferative activity of anti-Tn CICs of patients with IgAN. These findings could enhance both the diagnosis of IgAN and its treatment, as specific drug treatments are now unavailable.
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Affiliation(s)
- Yasuyuki Matsumoto
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Rajindra P. Aryal
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jamie Heimburg-Molinaro
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Simon S. Park
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Walter J. Wever
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Kathrin Stavenhagen
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Joanna A. E. van Wijk
- Department of Pediatric Nephrology, Amsterdam University Medical Centre, location VUmc, Amsterdam, Netherlands
| | - Irma Van Die
- Department of Molecular Cell Biology and Immunology, Amsterdam University Medical Centre, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Arlene B. Chapman
- Department of Medicine, Section of Nephrology, University of Chicago School of Medicine, Chicago, IL, USA
| | - Elliot L. Chaikof
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Richard D. Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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15
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Zhu X, Shen X, Lin B, Fang J, Jin J, He Q. Liuwei Dihuang Pills Inhibit Podocyte Injury and Alleviate IgA Nephropathy by Directly Altering Mesangial Cell-Derived Exosome Function and Secretion. Front Pharmacol 2022; 13:889008. [PMID: 35899112 PMCID: PMC9309816 DOI: 10.3389/fphar.2022.889008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/16/2022] [Indexed: 11/29/2022] Open
Abstract
Background: Immunoglobulin A nephropathy (IgAN) is the most common glomerular disease worldwide. Its pathological features include IgA immune complex deposition, accompanied by mesangial cell proliferation and mesangial matrix expansion. This study was conducted to investigate the effects of Liuwei Dihuang pills (LWDHW) on IgAN in mice and human podocytes, as well as to determine their underlying mechanisms of action. Methods: For in vitro experiments, podocytes were exposed to the human mesangial cell culture medium supernatant of glomerular cells treated with aggregated IgA1 (aIgA1) and LWDHW-containing serum. Cell viability and the proportion of positive cells were evaluated using CCK-8 and flow apoptosis kits, respectively. The cells were collected for western blot analysis. Twenty-four mice with IgAN induced by oral bovine serum albumin administration combined with tail vein injection of staphylococcal enterotoxin B were randomly divided into four groups of six mice each: untreated model group, model + LWDHW group, model + rapamycin group, and model + LWDHW + rapamycin group. The normal control group contained six mice. The red blood cell count in the urine, urine protein, blood urea nitrogen, serum creatinine, and IgA deposition were determined, and TUNEL and western blotting were performed in the mouse kidney tissues. Results:In vitro experiments showed that LWDHW promoted autophagy by regulating the PI3K/Akt/mTOR signalling pathway and improved the damage to podocytes caused by the aIgA1-treated mesangial cell supernatant. This study demonstrates the effectiveness of LWDHW for treating IgAN. In the animal experiments, LWDHW significantly reduced the urine red blood cell count, serum creatinine and urea nitrogen contents, and 24 h urinary protein function and improved IgA deposition in the kidney tissues, glomerular volume, glomerular cell proliferation and polysaccharide deposition, and glomerular cell apoptosis. The pills also reversed the changes in the LC3II/I ratio and p62 content in the kidney tissues. The combination of LWDHW and rapamycin showed stronger inhibitory effects compared to those of LWDHW or rapamycin alone. Conclusion: LWDHW may improve regulation of the PI3K-Akt-mTOR pathway and inhibit autophagy in podocytes, as well as alleviate IgA nephropathy by directly altering mesangial cell exosomes.
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Affiliation(s)
- Xiaodong Zhu
- Bengbu Medical College, Bengbu, China
- Urology and Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, China
| | - Xiaogang Shen
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Bo Lin
- Urology and Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, China
| | - Jiaxi Fang
- Urology and Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, China
| | - Juan Jin
- Urology and Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, China
- *Correspondence: Juan Jin, ; Qiang He,
| | - Qiang He
- Urology and Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, China
- *Correspondence: Juan Jin, ; Qiang He,
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16
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Crohn's disease may promote inflammation in IgA nephropathy: a case-control study of patients undergoing kidney biopsy. Virchows Arch 2022; 481:553-563. [PMID: 35809093 PMCID: PMC9534821 DOI: 10.1007/s00428-022-03373-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 06/06/2022] [Accepted: 06/24/2022] [Indexed: 11/02/2022]
Abstract
Intestinal immunity has been closely associated with the pathogenesis and progression of renal diseases, a relationship known as the "gut-kidney axis." To determine the association between immunoglobulin A nephropathy (IgAN) and Crohn's disease (CD), a clinico-pathological study was performed on patients who had IgAN with CD (CD-IgAN) and without CD (NOS-IgAN). We enrolled 29 patients diagnosed with IgAN via renal biopsy at the Tokyo Yamate Medical Center from 2009 to 2017. The patients were divided into CD-IgAN (n = 18) and NOS-IgAN (n = 11) and evaluated for clinical and pathological findings. IgA subclasses and galactose-deficient IgA1 (Gd-IgA1) were examined via immunohistochemistry using formalin-fixed paraffin-embedded sections from renal biopsy. Our results showed no significant difference in the extent of mesangial IgA subclasses or Gd-IgA1 deposition according to the presence or absence of CD. Pathologically, however, those with CD-IgAN had remarkably higher percentage of global glomerulosclerosis and extent of interstitial fibrosis and tubular atrophy (IF/TA) compared to those with NOS-IgAN. Moreover, the extent of macrophage infiltration in the glomerulus and interstitium was significantly higher in CD-IgAN than in NOS-IgAN. Clinically, the CD-IgAN group had significantly worse responsiveness to steroid treatment compared to the NOS-IgAN group. In conclusion, the similar immunological characteristics of deposited IgA molecules in the glomeruli between the CD-IgAN and NOS-IgAN groups might suggest their etiological similarity. However, a renal pathology showing advanced glomerular and tubulointerstitial sclerosis accompanying increased macrophage infiltration and highly resistant clinical features in patients with CD-IgAN suggests that some pathophysiological factors in CD, including abnormal intestinal immunity, may promote and activate the inflammatory process in IgAN via undetermined mechanisms.
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17
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Person T, King RG, Rizk DV, Novak J, Green TJ, Reily C. Cytokines and Production of Aberrantly O-Glycosylated IgA1, the Main Autoantigen in IgA Nephropathy. J Interferon Cytokine Res 2022; 42:301-315. [PMID: 35793525 PMCID: PMC9536348 DOI: 10.1089/jir.2022.0039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/16/2022] [Indexed: 01/09/2023] Open
Abstract
Immunoglobulin A (IgA) nephropathy is the most common primary glomerulonephritis worldwide, with no disease-specific treatment and up to 40% of patients progressing to kidney failure. IgA nephropathy (IgAN), characterized by IgA1-containing immunodeposits in the glomeruli, is considered to be an autoimmune disease in which the kidneys are injured as innocent bystanders. Glomerular immunodeposits are thought to originate from the circulating immune complexes that contain aberrantly O-glycosylated IgA1, the main autoantigen in IgAN, bound by IgG autoantibodies. A common clinical manifestation associated with IgAN includes synpharyngitic hematuria at disease onset or during disease activity. This observation suggests a connection of disease pathogenesis with an activated mucosal immune system of the upper-respiratory and/or gastrointestinal tract and IgA1 glycosylation. In fact, some cytokines can enhance production of aberrantly O-glycosylated IgA1. This process involves abnormal cytokine signaling in IgA1-producing cells from patients with IgAN. In this article, we present our view of pathogenesis of IgAN and review how some cytokines can contribute to the disease process by enhancing production of aberrantly glycosylated IgA1. We also review current clinical trials of IgAN based on cytokine-targeting therapeutic approaches.
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Affiliation(s)
- Taylor Person
- Department of Microbiology and Birmingham, Alabama, USA
| | - R. Glenn King
- Department of Microbiology and Birmingham, Alabama, USA
| | - Dana V. Rizk
- Department of Medicine University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jan Novak
- Department of Microbiology and Birmingham, Alabama, USA
| | - Todd J. Green
- Department of Microbiology and Birmingham, Alabama, USA
| | - Colin Reily
- Department of Microbiology and Birmingham, Alabama, USA
- Department of Medicine University of Alabama at Birmingham, Birmingham, Alabama, USA
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18
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Vattepu R, Sneed SL, Anthony RM. Sialylation as an Important Regulator of Antibody Function. Front Immunol 2022; 13:818736. [PMID: 35464485 PMCID: PMC9021442 DOI: 10.3389/fimmu.2022.818736] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/17/2022] [Indexed: 12/14/2022] Open
Abstract
Antibodies play a critical role in linking the adaptive immune response to the innate immune system. In humans, antibodies are categorized into five classes, IgG, IgM, IgA, IgE, and IgD, based on constant region sequence, structure, and tropism. In serum, IgG is the most abundant antibody, comprising 75% of antibodies in circulation, followed by IgA at 15%, IgM at 10%, and IgD and IgE are the least abundant. All human antibody classes are post-translationally modified by sugars. The resulting glycans take on many divergent structures and can be attached in an N-linked or O-linked manner, and are distinct by antibody class, and by position on each antibody. Many of these glycan structures on antibodies are capped by sialic acid. It is well established that the composition of the N-linked glycans on IgG exert a profound influence on its effector functions. However, recent studies have described the influence of glycans, particularly sialic acid for other antibody classes. Here, we discuss the role of glycosylation, with a focus on terminal sialylation, in the biology and function across all antibody classes. Sialylation has been shown to influence not only IgG, but IgE, IgM, and IgA biology, making it an important and unappreciated regulator of antibody function.
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Affiliation(s)
- Ravi Vattepu
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sunny Lyn Sneed
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Robert M Anthony
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
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19
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Zachova K, Jemelkova J, Kosztyu P, Ohyama Y, Takahashi K, Zadrazil J, Orsag J, Matousovic K, Galuszkova D, Petejova N, Mestecky J, Raska M. Galactose-Deficient IgA1 B cells in the Circulation of IgA Nephropathy Patients Carry Preferentially Lambda Light Chains and Mucosal Homing Receptors. J Am Soc Nephrol 2022; 33:908-917. [PMID: 35115327 PMCID: PMC9063893 DOI: 10.1681/asn.2021081086] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Background: Immunoglobulin A nephropathy (IgAN) primary glomerulonephritis is characterized by the deposition of circulating immune complexes (CIC) composed of polymeric (p)IgA1 molecules with altered O-glycans (Gd-IgA1) and anti-glycan antibodies in the kidney mesangium. The mesangial IgA deposits and serum IgA1 contain predominantly lambda (λ) light (L) chain, but the nature and origin of such IgA remains enigmatic Methods: We analyzed λ L chain expression in peripheral blood B cells of 30 IgAN patients, 30 healthy controls (HC), and 18 membranous nephropathy patients selected as disease controls (Non-IgAN). Results: In comparison to HC and Non-IgAN, in peripheral blood surface/membrane bound (mb)-Gd-IgA1+ cells from IgAN patients express predominantly λ L chain. In contrast, total mb-IgA+, mb-IgG+, and mb-IgM+ cells were preferentially positive for kappa (κ) L chain, in all analyzed groups. Although minor in comparison to κ L chain, λ L chain subsets of mb-IgG+, mb-IgM,+ and mb-IgA+ cells were significantly enriched in IgAN in comparison to Non-IgAN and/or HC. In contrast to HC, the peripheral blood of IgAN patients was enriched for λ+ mb-Gd-IgA1,+ CCR10,+ and CCR9+ cells, which preferentially home to the upper respiratory and digestive tract, respectively. Furthermore, we observed that mb-Gd-IgA1+ cell populations comprise more CD138+ cells and plasmablasts (CD38+) in comparison to total mb-IgA+ cells. Conclusions: Peripheral blood of IgAN patients is enriched for migratory λ+ mb-GdIgA1+ B cells, with the potential to home to mucosal sites where Gd-IgA1 could be produced during local respiratory or digestive tract infections.
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Affiliation(s)
- Katerina Zachova
- K Zachova, Department of Immunology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jana Jemelkova
- J Jemelkova, Department of Immunology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Petr Kosztyu
- P Kosztyu, Department of Immunology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Yukako Ohyama
- Y Ohyama, Department of Biomedical Molecular Sciences, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Kazuo Takahashi
- K Takahashi, Department of Biomedical Molecular Sciences, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Josef Zadrazil
- J Zadrazil, Department of Internal Medicine III Nephrology, Rheumatology and Endocrinology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jiri Orsag
- J Orsag, Department of Internal Medicine III Nephrology, Rheumatology and Endocrinology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Karel Matousovic
- K Matousovic, Department of Medicine, Charles University Second Faculty of Medicine, Praha, Czech Republic
| | - Dana Galuszkova
- D Galuszkova, Department of Transfusion Medicine, University Hospital Olomouc, Olomouc, Czech Republic
| | - Nadezda Petejova
- N Petejova, Department of Internal Medicine III Nephrology, Rheumatology and Endocrinology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jiri Mestecky
- J Mestecky, Departments of Microbiology and Medicine, The University of Alabama at Birmingham, Birmingham, United States
| | - Milan Raska
- M Raska, Department of Immunology, Palacky University Olomouc, Olomouc, Czech Republic
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20
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Zeng H, Wang L, Li J, Luo S, Han Q, Su F, Wei J, Wei X, Wu J, Li B, Huang J, Tang P, Cao C, Zhou Y, Yang Q. Single-cell RNA-sequencing reveals distinct immune cell subsets and signaling pathways in IgA nephropathy. Cell Biosci 2021; 11:203. [PMID: 34895340 PMCID: PMC8665497 DOI: 10.1186/s13578-021-00706-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/31/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most common primary glomerulonephritis globally. Increasing evidence suggests the importance of host immunity in the development of IgAN, but its dynamics during the early stage of IgAN are still largely unclear. RESULTS Here we successfully resolved the early transcriptomic changes in immune cells of IgAN by conducting single-cell RNA-sequencing (scRNA-seq) with peripheral blood mononuclear cells. The differentially expressed genes (DEGs) between control and IgAN were predominantly enriched in NK cell-mediated cytotoxicity and cell killing pathways. Interestingly, we discovered that the number and cytotoxicity of NK cells are significantly reduced in IgAN patients, where both the number and marker genes of NK cells were negatively associated with the clinical parameters, including the levels of urine protein creatinine ratio (UPCR), serum galactose-deficient IgA1 and IgA. A distinctive B cell subset, which had suppressed NFκB signaling was predominantly in IgAN and positively associated with disease progression. Moreover, the DEGs of B cells were enriched in different viral infection pathways. Classical monocytes also significantly changed in IgAN and a monocyte subset expressing interferon-induced genes was positively associated with the clinical severity of IgAN. Finally, we identified vast dynamics in intercellular communications in IgAN. CONCLUSIONS We dissected the immune landscape of IgAN at the single-cell resolution, which provides new insights in developing novel biomarkers and immunotherapy against glomerulonephritis.
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Affiliation(s)
- Honghui Zeng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Le Wang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Jiajia Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Siweier Luo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Qianqian Han
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Fang Su
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Jing Wei
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Xiaona Wei
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Jianping Wu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Bin Li
- Clinical Trials Unit, The First Affiliated Hospital of Sun Yat-Sen University, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Jingang Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - Patrick Tang
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Chunwei Cao
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
| | - Yiming Zhou
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
- Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
| | - Qiongqiong Yang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
- Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
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21
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Pathogenesis of IgA Nephropathy: Current Understanding and Implications for Development of Disease-Specific Treatment. J Clin Med 2021; 10:jcm10194501. [PMID: 34640530 PMCID: PMC8509647 DOI: 10.3390/jcm10194501] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 12/20/2022] Open
Abstract
IgA nephropathy, initially described in 1968 as a kidney disease with glomerular “intercapillary deposits of IgA-IgG”, has no disease-specific treatment and is a common cause of kidney failure. Clinical observations and laboratory analyses suggest that IgA nephropathy is an autoimmune disease wherein the kidneys are damaged as innocent bystanders due to deposition of IgA1-IgG immune complexes from the circulation. A multi-hit hypothesis for the pathogenesis of IgA nephropathy describes four sequential steps in disease development. Specifically, patients with IgA nephropathy have elevated circulating levels of IgA1 with some O-glycans deficient in galactose (galactose-deficient IgA1) and these IgA1 glycoforms are recognized as autoantigens by unique IgG autoantibodies, resulting in formation of circulating immune complexes, some of which deposit in glomeruli and activate mesangial cells to induce kidney injury. This proposed mechanism is supported by observations that (i) glomerular immunodeposits in patients with IgA nephropathy are enriched for galactose-deficient IgA1 glycoforms and the corresponding IgG autoantibodies; (ii) circulatory levels of galactose-deficient IgA1 and IgG autoantibodies predict disease progression; and (iii) pathogenic potential of galactose-deficient IgA1 and IgG autoantibodies was demonstrated in vivo. Thus, a better understanding of the structure–function of these immunoglobulins as autoantibodies and autoantigens will enable development of disease-specific treatments.
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22
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Seikrit C, Pabst O. The immune landscape of IgA induction in the gut. Semin Immunopathol 2021; 43:627-637. [PMID: 34379174 PMCID: PMC8551147 DOI: 10.1007/s00281-021-00879-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/09/2021] [Indexed: 12/14/2022]
Abstract
Antibodies are key elements of protective immunity. In the mucosal immune system in particular, secretory immunoglobulin A (SIgA), the most abundantly produced antibody isotype, protects against infections, shields the mucosal surface from toxins and environmental factors, and regulates immune homeostasis and a peaceful coexistence with our microbiota. However, the dark side of IgA biology promotes the formation of immune complexes and provokes pathologies, e.g., IgA nephropathy (IgAN). The precise mechanisms of how IgA responses become deregulated and pathogenic in IgAN remain unresolved. Yet, as the field of microbiota research moved into the limelight, our basic understanding of IgA biology has been taking a leap forward. Here, we discuss the structure of IgA, the anatomical and cellular foundation of mucosal antibody responses, and current concepts of how we envision the interaction of SIgA and the microbiota. We center on key concepts in the field while taking account of both historic findings and exciting new observations to provide a comprehensive groundwork for the understanding of IgA biology from the perspective of a mucosal immunologist.
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Affiliation(s)
- Claudia Seikrit
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Oliver Pabst
- Institute of Molecular Medicine, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
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23
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Ohyama Y, Renfrow MB, Novak J, Takahashi K. Aberrantly Glycosylated IgA1 in IgA Nephropathy: What We Know and What We Don't Know. J Clin Med 2021; 10:jcm10163467. [PMID: 34441764 PMCID: PMC8396900 DOI: 10.3390/jcm10163467] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022] Open
Abstract
IgA nephropathy (IgAN), the most common primary glomerular disease worldwide, is characterized by glomerular deposition of IgA1-containing immune complexes. The IgA1 hinge region (HR) has up to six clustered O-glycans consisting of Ser/Thr-linked N-acetylgalactosamine usually with β1,3-linked galactose and variable sialylation. Circulating levels of IgA1 with abnormally O-glycosylated HR, termed galactose-deficient IgA1 (Gd-IgA1), are increased in patients with IgAN. Current evidence suggests that IgAN is induced by multiple sequential pathogenic steps, and production of aberrantly glycosylated IgA1 is considered the initial step. Thus, the mechanisms of biosynthesis of aberrantly glycosylated IgA1 and the involvement of aberrant glycoforms of IgA1 in disease development have been studied. Furthermore, Gd-IgA1 represents an attractive biomarker for IgAN, and its clinical significance is still being evaluated. To elucidate the pathogenesis of IgAN, it is important to deconvolute the biosynthetic origins of Gd-IgA1 and characterize the pathogenic IgA1 HR O-glycoform(s), including the glycan structures and their sites of attachment. These efforts will likely lead to development of new biomarkers. Here, we review the IgA1 HR O-glycosylation in general and the role of aberrantly glycosylated IgA1 in the pathogenesis of IgAN in particular.
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Affiliation(s)
- Yukako Ohyama
- Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan;
| | - Matthew B. Renfrow
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.B.R.); (J.N.)
| | - Jan Novak
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.B.R.); (J.N.)
| | - Kazuo Takahashi
- Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan;
- Correspondence: ; Tel.: +81-(562)-93-2430; Fax: +81-(562)-93-1830
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24
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Kim HW, Park JT, Joo YS, Kang SC, Lee JY, Lee S, Chang TI, Kang EW, Ryu DR, Yoo TH, Chin HJ, Kang SW, Han SH. Systolic blood pressure and chronic kidney disease progression in patients with primary glomerular disease. J Nephrol 2021; 34:1057-1067. [PMID: 33555575 DOI: 10.1007/s40620-020-00930-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Many current guidelines on optimal target blood pressure (BP) for chronic kidney disease (CKD) patients are largely based on studies in diabetic and hypertensive patients. However, there have been few studies in patients with glomerular diseases. METHODS We retrospectively studied the longitudinal association between BP and CKD progression in 1,066 biopsy-proven patients diagnosed with primary glomerular diseases, including IgA nephropathy, membranous nephropathy (MN), and focal segmental glomerulosclerosis (FSGS), between 2005 and 2017. The main predictor was time-updated systolic blood pressure (SBP) at every clinic visit. The primary outcome was a composite one including ≥ 50% decrease in estimated glomerular filtration rate (eGFR) from the baseline, and end-stage kidney disease (ESKD). RESULTS During 5009 person-years of follow-up, the primary outcome occurred in 157 (14.7%) patients. In time-varying Cox model, the adjusted hazard ratios (HRs) (95% confidence interval (CI)) for the primary outcome were 1.48 (0.96-2.29), 2.07 (1.22-3.52), and 2.53 (1.13-5.65) for SBP of 120-129, 130-139, and ≥ 140 mmHg, respectively, compared with SBP < 120 mmHg. This association was particularly evident in patients with elevated proteinuria. However, there was no association between baseline SBP and adverse kidney outcomes. Finally, prediction models failed to show the improvement of predictive performance of SBP compared with that of remission status. Moreover, patients with remission and less controlled SBP had better kidney outcomes than those with non-remission and well-controlled SBP. CONCLUSION Among patients with glomerular disease, higher time-updated SBP was significantly associated with higher risk of CKD progression. However, the clinical significance of blood pressure was less powerful than remission status.
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Affiliation(s)
- Hyung Woo Kim
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Jung Tak Park
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Young Su Joo
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
- Division of Nephrology, Department of Internal Medicine, Myongji Hospital, Goyang, South Korea
| | - Shin Chan Kang
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Jee Young Lee
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Sangmi Lee
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Tae Ik Chang
- Department of Internal Medicine, National Health Insurance Corporation Medical Center, Ilsan Hospital, Goyang si, South Korea
| | - Ea Wha Kang
- Department of Internal Medicine, National Health Insurance Corporation Medical Center, Ilsan Hospital, Goyang si, South Korea
| | - Dong-Ryeol Ryu
- Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, South Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Ho Jun Chin
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Shin-Wook Kang
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Seung Hyeok Han
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea.
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25
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Hansen AL, Reily C, Novak J, Renfrow MB. Immunoglobulin A Glycosylation and Its Role in Disease. EXPERIENTIA SUPPLEMENTUM (2012) 2021; 112:433-477. [PMID: 34687019 DOI: 10.1007/978-3-030-76912-3_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Human IgA is comprised of two subclasses, IgA1 and IgA2. Monomeric IgA (mIgA), polymeric IgA (pIgA), and secretory IgA (SIgA) are the main molecular forms of IgA. The production of IgA rivals all other immunoglobulin isotypes. The large quantities of IgA reflect the fundamental roles it plays in immune defense, protecting vulnerable mucosal surfaces against invading pathogens. SIgA dominates mucosal surfaces, whereas IgA in circulation is predominately monomeric. All forms of IgA are glycosylated, and the glycans significantly influence its various roles, including antigen binding and the antibody effector functions, mediated by the Fab and Fc portions, respectively. In contrast to its protective role, the aberrant glycosylation of IgA1 has been implicated in the pathogenesis of autoimmune diseases, such as IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). Furthermore, detailed characterization of IgA glycosylation, including its diverse range of heterogeneity, is of emerging interest. We provide an overview of the glycosylation observed for each subclass and molecular form of IgA as well as the range of heterogeneity for each site of glycosylation. In many ways, the role of IgA glycosylation is in its early stages of being elucidated. This chapter provides an overview of the current knowledge and research directions.
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Affiliation(s)
- Alyssa L Hansen
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Colin Reily
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA.
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26
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Stewart TJ, Takahashi K, Xu N, Prakash A, Brown R, Raska M, Renfrow MB, Novak J. Quantitative assessment of successive carbohydrate additions to the clustered O-glycosylation sites of IgA1 by glycosyltransferases. Glycobiology 2020; 31:540-556. [PMID: 33295603 DOI: 10.1093/glycob/cwaa111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 11/12/2022] Open
Abstract
Mucin-type O-glycosylation occurs on many proteins that transit the Golgi apparatus. These glycans impact structure and function of many proteins and have important roles in cellular biosynthetic processes, signaling and differentiation. Although recent technological advances have enhanced our ability to profile glycosylation of glycoproteins, limitations in the understanding of the biosynthesis of these glycan structures remain. Some of these limitations stem from the difficulty to track the biosynthetic process of mucin-type O-glycosylation, especially when glycans occur in dense clusters in repeat regions of proteins, such as the mucins or immunoglobulin A1 (IgA1). Here, we describe a series of nano-liquid chromatography (LC)-mass spectrometry (MS) analyses that demonstrate the range of glycosyltransferase enzymatic activities involved in the biosynthesis of clustered O-glycans on IgA1. By utilizing nano-LC-MS relative quantitation of in vitro reaction products, our results provide unique insights into the biosynthesis of clustered IgA1 O-glycans. We have developed a workflow to determine glycoform-specific apparent rates of a human UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltrasnfersase (GalNAc-T EC 2.4.1.41) and demonstrated how pre-existing glycans affect subsequent activity of glycosyltransferases, such as core 1 galactosyltransferase and α2,3- and α2,6-specific sialyltransferases, in successive additions in the biosynthesis of clustered O-glycans. In the context of IgA1, these results have potential to provide insight into the molecular mechanisms implicated in the pathogenesis of IgA nephropathy, an autoimmune renal disease involving aberrant IgA1 O-glycosylation. In a broader sense, these methods and workflows are applicable to the studies of the concerted and competing functions of other glycosyltransferases that initiate and extend mucin-type core 1 clustered O-glycosylation.
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Affiliation(s)
- Tyler J Stewart
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, BBRB 761A, Birmingham, AL 35294, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 720 20th Street South, KAUL 524, Birmingham, AL 35294, USA
| | - Kazuo Takahashi
- Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake, Aichi, Toyoake 470-1192, Japan.,Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, BBRB 761A, Birmingham, AL 35294, USA
| | - Nuo Xu
- Department of Management, Information Systems & Quantitative Methods, 710 13th Street South, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Amol Prakash
- Optys Tech Corporation, Shrewsbury, MA 01545, USA
| | - Rhubell Brown
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, BBRB 761A, Birmingham, AL 35294, USA
| | - Milan Raska
- Department of Immunology, Palacky University and University Hospital, Hnevotinska 3, Olomouc 775 15, Czech Republic
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 720 20th Street South, KAUL 524, Birmingham, AL 35294, USA
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, BBRB 761A, Birmingham, AL 35294, USA
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27
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Emerging Modes of Treatment of IgA Nephropathy. Int J Mol Sci 2020; 21:ijms21239064. [PMID: 33260613 PMCID: PMC7730306 DOI: 10.3390/ijms21239064] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/12/2022] Open
Abstract
IgA nephropathy is the most common primary glomerulonephritis with potentially serious outcome leading to end stage renal disease in 30 to 50% of patients within 20 to 30 years. Renal biopsy, which might be associated with risks of complications (bleeding and others), still remains the only reliable diagnostic tool for IgA nephropathy. Therefore, the search for non-invasive diagnostic and prognostic markers for detection of subclinical types of IgA nephropathy, evaluation of disease activity, and assessment of treatment effectiveness, is of utmost importance. In this review, we summarize treatment options for patients with IgA nephropathy including the drugs currently under evaluation in randomized control trials. An early initiation of immunosupressive regimens in patients with IgA nephropathy at risk of progression should result in the slowing down of the progression of renal function to end stage renal disease.
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28
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Zhang X, Zeng J, Tong Y, Zhang L, Lu X, Zhu S, Li Z. CDR3 sequences in IgA nephropathy are shorter and exhibit reduced diversity. FEBS Open Bio 2020; 10:2702-2711. [PMID: 33067920 PMCID: PMC7714077 DOI: 10.1002/2211-5463.13006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/20/2020] [Accepted: 10/15/2020] [Indexed: 11/10/2022] Open
Abstract
Immunoglobulin (Ig) A nephropathy (IgAN) is the most common glomerulonephritis, which is characterized by the deposition of IgA antibody in the glomerulus. Systematic dissection of immune composition may contribute to a better understanding of the alternations in the immune system in IgAN. To this end, here we applied immune repertoire sequencing technology for parallel analysis of the complementary determining region 3 (CDR3) of all B cell receptors, including all five antibody subtypes (IgA, IgG, IgM, IgE and IgD), in 13 patients with IgAN and 7 healthy individuals. A significant decrease in CDR3 length was observed in the IgAN group. In particular, the JH6 family was significantly increased in IgAN. Amino acid usage was also altered in IgAN. Shannon, Simpson, Gini and Diversity 50 indices also revealed significant differences in the diversity of IgG, IgM and IgA antibodies as compared with controls. The proportions of IgA and IgG were increased, whereas IgM was decreased in IgAN. Moreover, a greater number of CDR3 sequences was shared between patients with IgAN. These findings suggest that the BCR immune repertoire is dramatically altered in IgAN, as characterized by shortened CDR3 length, as well as decreased overall diversity of CDR3.
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Affiliation(s)
- Xi Zhang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.,Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Jianming Zeng
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Yin Tong
- Cancer Informatics and System Biology Lab, The University of Hong Kong, Hong Kong, China
| | - Li Zhang
- MD Anderson Cancer Center, Houston, TX, USA
| | - Xibin Lu
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Shenglang Zhu
- Department of Nephrology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| | - Zhoufang Li
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
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29
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Ohyama Y, Nakajima K, Renfrow MB, Novak J, Takahashi K. Mass spectrometry for the identification and analysis of highly complex glycosylation of therapeutic or pathogenic proteins. Expert Rev Proteomics 2020; 17:275-296. [PMID: 32406805 DOI: 10.1080/14789450.2020.1769479] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Protein glycosylation influences characteristics such as folding, stability, protein interactions, and solubility. Therefore, glycan moieties of therapeutic proteins and proteins that are likely associated with disease pathogenesis should be analyzed in-depth, including glycan heterogeneity and modification sites. Recent advances in analytical methods and instrumentation have enabled comprehensive characterization of highly complex glycosylated proteins. AREA COVERED The following aspects should be considered when analyzing glycosylated proteins: sample preparation, chromatographic separation, mass spectrometry (MS) and fragmentation methods, and bioinformatics, such as software solutions for data analyses. Notably, analysis of glycoproteins with heavily sialylated glycans or multiple glycosylation sites requires special considerations. Here, we discuss recent methodological advances in MS that provide detailed characterization of heterogeneous glycoproteins. EXPERT OPINION As characterization of complex glycosylated proteins is still analytically challenging, the function or pathophysiological significance of these proteins is not fully understood. To reproducibly produce desired forms of therapeutic glycoproteins or to fully elucidate disease-specific patterns of protein glycosylation, a highly reproducible and robust analytical platform(s) should be established. In addition to advances in MS instrumentation, optimization of analytical and bioinformatics methods and utilization of glycoprotein/glycopeptide standards is desirable. Ultimately, we envision that an automated high-throughput MS analysis will provide additional power to clinical studies and precision medicine.
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Affiliation(s)
- Yukako Ohyama
- Department of Nephrology, Fujita Health University School of Medicine , Toyoake, Japan.,Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine , Toyoake, Japan
| | - Kazuki Nakajima
- Center for Research Promotion and Support, Fujita Health University , Toyoake, Japan
| | - Matthew B Renfrow
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
| | - Jan Novak
- Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
| | - Kazuo Takahashi
- Department of Nephrology, Fujita Health University School of Medicine , Toyoake, Japan.,Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine , Toyoake, Japan.,Departments of Biochemistry and Molecular Genetics and Microbiology, University of Alabama at Birmingham , Birmingham, AL, USA
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Analysis of O-glycoforms of the IgA1 hinge region by sequential deglycosylation. Sci Rep 2020; 10:671. [PMID: 31959827 PMCID: PMC6971281 DOI: 10.1038/s41598-020-57510-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022] Open
Abstract
A common renal disease, immunoglobulin A (IgA) nephropathy (IgAN), is associated with glomerular deposition of IgA1-containing immune complexes. IgA1 hinge region (HR) has up to six clustered O-glycans consisting of Ser/Thr-linked N-acetylgalactosamine with β1,3-linked galactose and variable sialylation. IgA1 glycoforms with some galactose-deficient (Gd) HR O-glycans play a key role in IgAN pathogenesis. The clustered and variable O-glycans make the IgA1 glycomic analysis challenging and better approaches are needed. Here, we report a comprehensive analytical workflow for IgA1 HR O-glycoform analysis. We combined an automated quantitative analysis of the HR O-glycopeptide profiles with sequential deglycosylation to remove all but Gd O-glycans from the HR. The workflow was tested using serum IgA1 from healthy subjects. Twelve variants of glycopeptides corresponding to the HR with three to six O-glycans were detected; nine glycopeptides carried up to three Gd O-glycans. Sites with Gd O-glycans were unambiguously identified by electron-transfer/higher-energy collision dissociation tandem mass spectrometry. Extracted ion chromatograms of isomeric glycoforms enabled quantitative assignment of Gd sites. The most frequent Gd site was T236, followed by S230, T233, T228, and S232. The new workflow for quantitative profiling of IgA1 HR O-glycoforms with site-specific resolution will enable identification of pathogenic IgA1 HR O-glycoforms in IgAN.
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IgA subclasses have different effector functions associated with distinct glycosylation profiles. Nat Commun 2020; 11:120. [PMID: 31913287 PMCID: PMC6949214 DOI: 10.1038/s41467-019-13992-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 12/09/2019] [Indexed: 12/17/2022] Open
Abstract
Monomeric serum immunoglobulin A (IgA) can contribute to the development of various autoimmune diseases, but the regulation of serum IgA effector functions is not well defined. Here, we show that the two IgA subclasses (IgA1 and IgA2) differ in their effect on immune cells due to distinct binding and signaling properties. Whereas IgA2 acts pro-inflammatory on neutrophils and macrophages, IgA1 does not have pronounced effects. Moreover, IgA1 and IgA2 have different glycosylation profiles, with IgA1 possessing more sialic acid than IgA2. Removal of sialic acid increases the pro-inflammatory capacity of IgA1, making it comparable to IgA2. Of note, disease-specific autoantibodies in patients with rheumatoid arthritis display a shift toward the pro-inflammatory IgA2 subclass, which is associated with higher disease activity. Taken together, these data demonstrate that IgA effector functions depend on subclass and glycosylation, and that disturbances in subclass balance are associated with autoimmune disease. Immunoglobulin A (IgA) has two subclasses, IgA1 and IgA2, but differential effects on inflammation are unclear. Here the authors show that IgA2, when compared with IgA1, has stronger pro-inflammatory functions associated with changed glycosylation and higher disease scores in patients with rheumatoid arthritis.
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Alvarado AS, Andeen NK, Brodsky S, Hinton A, Nadasdy T, Alpers CE, Blosser C, Najafian B, Rovin BH. Location of glomerular immune deposits, not codeposition of immunoglobulin G, influences definitive renal outcomes in immunoglobulin A nephropathy. Nephrol Dial Transplant 2019; 33:1168-1175. [PMID: 28992348 DOI: 10.1093/ndt/gfx238] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 06/13/2017] [Indexed: 12/25/2022] Open
Abstract
Background It has been suggested that the prognosis of immunoglobulin (IgA) nephropathy (IgAN) is adversely affected if there is codeposition of IgG in the glomeruli or if immune deposits are present in the glomerular capillary walls. We sought to understand how these variables affect clinical outcome. Methods A total of 80 IgAN biopsies were retrospectively divided into groups: (i) IgA without IgG deposition versus IgA + IgG and (ii) immune deposits restricted to the mesangium versus mesangium and peripheral capillary walls (PCWs). The association of these groups with the composite primary outcome of renal replacement therapy, renal transplant, death or doubling of serum creatinine (SCr) concentration was determined. The change in estimated glomerular filtration rate (eGFR) was also assessed. Covariates examined were age, sex, race, SCr and proteinuria level at biopsy and at follow-up, duration of follow-up, treatment, Oxford score and presence of crescents. Results IgG codeposition showed a trend toward endocapillary hypercellularity (P = 0.082); there were no other baseline differences between the IgA (n = 55) and IgA + IgG (n = 25) groups. At a median follow-up time of 29 months, the combined primary outcome was reached in 24 patients, 16 with IgA and 8 with IgA + IgG (P = 0.82). Patients with immune deposits in the PCWs (n = 21) presented with higher baseline proteinuria than those with deposits limited to the mesangium (n = 59; P = 0.025), were more likely to have crescents/segmental glomerular necrosis on biopsy (P = 0.047) and were more likely to reach the combined primary outcome (P = 0.026). Biopsies with crescents/segmental glomerular necrosis were associated with endocapillary hypercellularity (P < 0.001). Conclusions In this multicenter IgAN cohort, IgG co-deposition and the location of glomerular immune deposits in the PCWs were both associated with greater histologic activity on renal biopsy, but only the location of glomerular immune deposits in the PCWs was associated with a significantly increased risk for end-stage renal disease, transplant, death and/or doubling of SCr.
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Affiliation(s)
- Anthony S Alvarado
- Department of Medicine, Division of Nephrology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Nicole K Andeen
- Department of Pathology, University of Washington Medical Center, Seattle WA, USA
| | - Sergey Brodsky
- Department of Pathology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Alice Hinton
- Division of Biostatistics, College of Public Health, Ohio State University, Columbus, OH, USA
| | - Tibor Nadasdy
- Department of Pathology, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Charles E Alpers
- Department of Pathology, University of Washington Medical Center, Seattle WA, USA
| | - Christopher Blosser
- Department of Medicine, Nephrology Division, University of Washington Medical Center, Seattle, WA, USA
| | - Behzad Najafian
- Department of Pathology, University of Washington Medical Center, Seattle WA, USA
| | - Brad H Rovin
- Department of Medicine, Division of Nephrology, Ohio State University Wexner Medical Center, Columbus, OH, USA
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Zhang X, Xie X, Shi S, Liu L, Lv J, Zhang H. Plasma galactose-deficient immunoglobulin A1 and loss of kidney function in patients with immunoglobulin A vasculitis nephritis. Nephrol Dial Transplant 2019; 35:2117-2123. [PMID: 31377786 DOI: 10.1093/ndt/gfz151] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 06/18/2019] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Immunoglobulin A (IgA) vasculitis nephritis (IgAV-N) is the most common secondary IgA nephropathy (IgAN). Many studies have demonstrated that galactose-deficient IgA1 (Gd-IgA1) in the IgA1 hinge region is associated with the development and also progression of primary IgAN. In this study, we aimed to evaluate the roles of Gd-IgA1 in kidney disease progression in a large Chinese cohort of IgAV-N patients.
Methods
This cohort study enrolled 112 patients with IgAV-N, 15 patients with IgA vasculitis (IgAV) without kidney involvement and 108 patients with IgAN. Plasma IgA1 and Gd-IgA1 levels at kidney biopsy were measured by enzyme-linked immunosorbent assay. The primary endpoint was a 30% decline in estimated glomerular filtration rate or end-stage renal disease or death.
Results
The levels of Gd-IgA1 in IgAV-N and IgAN patients were higher than in healthy controls (mean ± SD, 302.86 ± 54.93 U/mL versus 303.16 ± 59.43 U/mL versus 281.30 ± 43.74 U/mL, respectively; P = 0.047), as well as compared with those with IgAV without kidney involvement (272.65 ± 53.14 U/mL; P = 0.036). After adjusting clinical data, higher levels of Gd-IgA1 were found to be independently associated with a greater risk for kidney failure [hazard ratio (HR) = 1.703 per 1 SD, 95% confidence interval (CI) 1.233–2.352; P = 0.001]. Compared with the first Gd-IgA1 quartile group (as reference), the fourth Gd-IgA1 quartile group retained a predictive value for poor renal outcome (HR = 3.740, 95% CI 1.204–11.619; P = 0.023).
Conclusions
These data indicate that Gd-IgA1 levels were similarly elevated in adult patients with IgAN and those with IgAV-N. Moreover, increased Gd-IgA1 levels were associated with both the development and progression of IgAV-N, as observed in IgAN.
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Affiliation(s)
- Xue Zhang
- Renal Division, 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
| | - Xinfang Xie
- Renal Division, 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
| | - Sufang Shi
- Renal Division, 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
| | - Lijun Liu
- Renal Division, 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
| | - Jicheng Lv
- Renal Division, 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, 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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Nakazawa S, Imamura R, Kawamura M, Kato T, Abe T, Iwatani H, Yamanaka K, Uemura M, Kishikawa H, Nishimura K, Tajiri M, Wada Y, Nonomura N. Evaluation of IgA1 O-glycosylation in Henoch-Schönlein Purpura Nephritis Using Mass Spectrometry. Transplant Proc 2019; 51:1481-1487. [DOI: 10.1016/j.transproceed.2019.01.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023]
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Abstract
IgA nephropathy (IgAN) represents a genetically complex multifactorial trait. Its prevalence and clinical features vary geographically, and the disease has a range of clinical presentations that suggest multiple subtypes. Although familial aggregation of IgAN has been reported and prior linkage studies have highlighted significant locus heterogeneity, specific genetic variants underlying familial IgAN have not yet been defined. Population-based genome-wide association studies (GWAS) have discovered nearly 20 IgAN risk loci, providing novel insights into disease epidemiology and molecular mechanisms, shifting old paradigms of the disease pathogenesis. Follow-up fine-mapping studies have identified specific causal variants, and genotype-phenotype correlation studies have begun to delineate clinical consequences of GWAS risk alleles. The association between IgAN and galactose-deficient IgA1 (Gd-IgA1), a validated serum biomarker of IgAN, presented another avenue for genetic discovery because elevated serum levels of Gd-IgA1 are highly heritable. Recent GWAS for serum Gd-IgA1 levels provided novel insights into genetic regulation of this trait, but the genetic link between Gd-IgA1 and IgAN has not yet been established. In this review, we discuss these developments in the broader context of modern genetic approaches to complex traits, and provide our perspective on the critical challenges that need to be addressed to advance the field.
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Affiliation(s)
- Y Dana Neugut
- Division of Nephrology, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Krzysztof Kiryluk
- Division of Nephrology, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY.
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Ouyang Y, Zhu L, Shi M, Yu S, Jin Y, Wang Z, Ma J, Yang M, Zhang X, Pan X, Ren H, Wang W, Zhang H, Xie J, Chen N. A Rare Genetic Defect of MBL2 Increased the Risk for Progression of IgA Nephropathy. Front Immunol 2019; 10:537. [PMID: 30967869 PMCID: PMC6438956 DOI: 10.3389/fimmu.2019.00537] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/27/2019] [Indexed: 12/23/2022] Open
Abstract
The aim of this study was to investigate the association between lectin pathway-related genetic variations and progression in IgA nephropathy. Biopsy-proven IgAN patients with eGFR ≥15 ml/min/1.73 m2 at baseline and a minimum follow-up of 12-months were enrolled. A total of 1,007 patients and 121 healthy controls were enrolled from two Chinese renal centers. The discovery cohort consisted of 606 patients, and the validation cohort consisted of 401 patients. First, promoters, all exons and their boundary regions of MBL2 and FCN2 were sequenced in 50 patients, and then 37 variations were identified. Of these variations, 7 expression-associated variations were selected and genotyped in the whole discovery cohort. We found that rs1800450 in MBL2 and rs7851696 in FCN2 were associated with an increased risk for ESRD as well as serum MBL or L-ficolin levels. However, only rs1800450 was successively validated for its association with ESRD (HR, 15.91; 3.27-77.34; P = 0.001) in the fully adjusted model in the validation cohort. In addition, 2.7% of patients, and 2.5% of healthy controls carried rs1800450-AA. IgAN patients with rs1800450-AA lacked expression of MBL in both serum and renal tissue and had more severe tubulointerstitial damage. Furthermore, a combined effect of rs1800450-AA with a previously reported clinical risk score was observed in which patients with both a high clinical risk score (≥1%) and rs1800450-AA had a strikingly increased 10-years ESRD risk by 37.1-fold (7.17 to 192.13-fold). In summary, IgAN patients carrying MBL2 rs1800450-AA have a high risk for renal function deterioration, probably due to inactivation of the complement MBL pathway.
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Affiliation(s)
- Yan Ouyang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
| | - Manman Shi
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuwen Yu
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuanmeng Jin
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhaohui Wang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Ma
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meng Yang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoyan Zhang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoxia Pan
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hong Ren
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiming Wang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
| | - Jingyuan Xie
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nan Chen
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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37
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Rizk DV, Maillard N, Julian BA, Knoppova B, Green TJ, Novak J, Wyatt RJ. The Emerging Role of Complement Proteins as a Target for Therapy of IgA Nephropathy. Front Immunol 2019; 10:504. [PMID: 30941137 PMCID: PMC6433978 DOI: 10.3389/fimmu.2019.00504] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/25/2019] [Indexed: 12/28/2022] Open
Abstract
IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and a common cause of end-stage renal disease. Evaluation of a kidney biopsy is necessary for diagnosis, with routine immunofluorescence microscopy revealing dominant or co-dominant IgA immunodeposits usually with complement C3 and sometimes IgG and/or IgM. IgA nephropathy reduces life expectancy by more than 10 years and leads to kidney failure in 20–40% of patients within 20 years of diagnosis. There is accumulating clinical, genetic, and biochemical evidence that complement plays an important role in the pathogenesis of IgA nephropathy. The presence of C3 differentiates the diagnosis of IgA nephropathy from the subclinical deposition of glomerular IgA. Markers for the activation of the alternative and mannan-binding lectin (MBL) pathways in renal-biopsy specimens are associated with disease activity and portend a worse renal outcome. Complement proteins in the circulation have also been evaluated in IgA nephropathy and found to be of prognostic value. Recently, genetic studies have identified IgA nephropathy-associated loci. Within these loci are genes encoding products involved in complement regulation and interaction with immune complexes. Put together, these data identify the complement cascade as a rational treatment target for this chronic kidney disease. Recent case reports on the successful use of humanized anti-C5 monoclonal antibody eculizumab are consistent with this hypothesis, but a better understanding of the role of complement in IgA nephropathy is needed to guide future therapeutic interventions.
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Affiliation(s)
- Dana V Rizk
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Nicolas Maillard
- Department of Nephrology, Dialysis, Transplantation, CHU de Saint-Etienne, GIMAP, EA3064, Université Jean Monnet, COMUE Université de Lyon, Rhône-Alpes, France
| | - Bruce A Julian
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Barbora Knoppova
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czechia
| | - Todd J Green
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Robert J Wyatt
- Department of Pediatrics, University of Tennessee Health Sciences Center, Memphis, TN, United States
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38
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Lomax-Browne HJ, Robertson C, Antonopoulos A, Leathem AJC, Haslam SM, Dell A, Dwek MV. Serum IgA1 shows increased levels of α2,6-linked sialic acid in breast cancer. Interface Focus 2019; 9:20180079. [PMID: 30842877 DOI: 10.1098/rsfs.2018.0079] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2019] [Indexed: 12/12/2022] Open
Abstract
The lectin Helix pomatia agglutinin (HPA) recognizes altered glycosylation in solid cancers and the identification of HPA binding partners in tumour tissue and serum is an important aim. Among the many HPA binding proteins, IgA1 has been reported to be the most abundant in liver metastases. In this study, the glycosylation of IgA1 was evaluated using serum samples from patients with breast cancer (BCa) and the utility of IgA1 glycosylation as a biomarker was assessed. Detailed mass spectrometric structural analysis showed an increase in disialo-biantennary N-linked glycans on IgA1 from BCa patients (p < 0.0001: non-core fucosylated; p = 0.0345: core fucosylated) and increased asialo-Thomsen-Friedenreich antigen (TF) and disialo-TF antigens in the O-linked glycan preparations from IgA1 of cancer patients compared with healthy control individuals. An increase in Sambucus nigra binding was observed, suggestive of increased α2,6-linked sialic acid on IgA1 in BCa. Logistic regression analysis showed HPA binding to IgA1 and tumour size to be significant independent predictors of distant metastases (χ 2 13.359; n = 114; p = 0.020) with positive and negative predictive values of 65.7% and 64.6%, respectively. Immunohistochemical analysis of tumour tissue samples showed IgA1 to be detectable in BCa tissue. This report provides a detailed analysis of serum IgA1 glycosylation in BCa and illustrates the potential utility of IgA1 glycosylation as a biomarker for BCa prognostication.
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Affiliation(s)
- Hannah J Lomax-Browne
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Claire Robertson
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Aristotelis Antonopoulos
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Anthony J C Leathem
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
| | - Stuart M Haslam
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Anne Dell
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Miriam V Dwek
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK
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Yamasaki K, Suzuki H, Yasutake J, Yamazaki Y, Suzuki Y. Galactose-Deficient IgA1-Specific Antibody Recognizes GalNAc-Modified Unique Epitope on Hinge Region of IgA1. Monoclon Antib Immunodiagn Immunother 2018; 37:252-256. [PMID: 30570353 PMCID: PMC6338562 DOI: 10.1089/mab.2018.0041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Galactose-deficient IgA1 (Gd-IgA1) that exposes GalNAc or sialylated GalNAc has been shown to be associated with disease activity of IgA nephropathy (IgAN). In a previous report, we established an enzyme-linked immunosorbent assay that measures human Gd-IgA1 using a specific monoclonal antibody KM55 (KM55 mAb), and showed that patients with IgAN contain a higher level of serum Gd-IgA1 than other types of renal diseases. Recently, we also found that the KM55 mAb specifically recognized the glomerular-deposited Gd-IgA1 in renal biopsy. In this study, we aimed to analyze the epitope of KM55 mAb using synthesized peptides corresponding to the hinge region of IgA1 with GalNAc moiety on putative glycosylated Ser/Thr residues, which are Thr225, Thr228, Ser230, Ser232, and Thr236. Binding analysis to single GalNAc-modified hinge region peptide of IgA1 showed that Thr225 with GalNAc is required for recognition of KM55. PST(GalNAC)PP motif was required for KM55 mAb to recognize hinge region peptide of IgA1 which is shown by binding assay with deletion peptide. This result was confirmed by binding of KM55 mAb against peptide with GalNAc at Thr233, which resulted in containing another PST(GalNAC)PP motif. Taken together, we concluded that the epitope of Gd-IgA1-specific KM55 mAb is PST(GalNAc)PP motif.
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Affiliation(s)
- Kohei Yamasaki
- 1 Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan.,2 Nephrology R&D Unit, Kyowa Hakko Kirin Co., Ltd., Tokyo, Japan
| | - Hitoshi Suzuki
- 1 Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Junichi Yasutake
- 2 Nephrology R&D Unit, Kyowa Hakko Kirin Co., Ltd., Tokyo, Japan
| | - Yuji Yamazaki
- 2 Nephrology R&D Unit, Kyowa Hakko Kirin Co., Ltd., Tokyo, Japan
| | - Yusuke Suzuki
- 1 Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
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40
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Nakazawa S, Imamura R, Kawamura M, Kato T, Abe T, Namba T, Iwatani H, Yamanaka K, Uemura M, Kishikawa H, Nishimura K, Oka K, Tajiri M, Wada Y, Nonomura N. Difference in IgA1 O-glycosylation between IgA deposition donors and IgA nephropathy recipients. Biochem Biophys Res Commun 2018; 508:1106-1112. [PMID: 30553446 DOI: 10.1016/j.bbrc.2018.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 12/03/2018] [Indexed: 01/18/2023]
Abstract
IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis, and disease recurrence often occurs after transplantation. On the other hands, Asymptomatic IgA deposition (IgAD) is occasionally observed in donated kidney. It is recognized that IgAD does not progress to IgAN, but the mechanism has not demonstrated yet. In IgAN, aberrant IgA1 O-glycan structure in the hinge region (HR) of serum IgA is suggested as one of the most convincing key mediators. However, little is known about IgA1 O-glycan structure in IgAD patients. Herein, we investigated the prevalence of IgAD in living renal transplant donors in our cohort. IgAD was observed in 21(13.0%) among 161 renal transplant donors and have statistically significant blood relationship with IgAN recipients (28.6% in relatives vs. 9.8% in non-relatives, respectively; p = 0.0073). Next, we evaluated the IgA1 O-glycan structure of serum IgA from IgAN recipients (n = 26), IgAD donors (n = 17), and non-IgAD helthy donors (n = 27) using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The numbers of GalNAc and Gal and the Gal/GalNAc ratio in the HR of the IgAN recipients had significantly lower comparing to the IgAD and non-IgAD healthy donors. The decreased Gal/GalNAc ratio in IgAN recipients means the increased ratio of galactose-deficient IgA1. To the best of our knowledge, this is the first report to compare the O-glycan structures in IgAN recipients and IgAD donors using MALDI-TOF MS. We concluded that IgAD was more common in IgAN related donors. Overall, decreased GalNAc and Gal contents in HR could play a material pathogenic role in IgAN.
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Affiliation(s)
- Shigeaki Nakazawa
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ryoichi Imamura
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Masataka Kawamura
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taigo Kato
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Toyofumi Abe
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoko Namba
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hirotsugu Iwatani
- Department of Nephrology, National Hospital Organization, Osaka National Hospital, 2-1-14 Chuo-ku, Osaka, Osaka, 540-0006, Japan
| | - Kazuaki Yamanaka
- Department of Urology, Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya, Hyogo, 662-0918, Japan
| | - Motohide Uemura
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hidefumi Kishikawa
- Department of Urology, Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya, Hyogo, 662-0918, Japan
| | - Kenji Nishimura
- Department of Urology, Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya, Hyogo, 662-0918, Japan
| | - Kazumasa Oka
- Department of Pathology, Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya, Hyogo, 662-0918, Japan
| | - Michiko Tajiri
- Osaka Women's and Children's Hospital, Japan, 840 Murodo-cho, Izumi, Osaka, 594-1101, Japan
| | - Yoshinao Wada
- Osaka Women's and Children's Hospital, Japan, 840 Murodo-cho, Izumi, Osaka, 594-1101, Japan
| | - Norio Nonomura
- Department of Urology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Abstract
IgA nephropathy, the most common primary glomerulonephritis in the world and a frequent cause of end-stage renal disease, is characterized by typical mesangial deposits of IgA1, as described by Berger and Hinglaise in 1968. Since then, it has been discovered that aberrant IgA1 O-glycosylation is involved in disease pathogenesis. Progress in glycomic, genomic, clinical, analytical, and biochemical studies has shown autoimmune features of IgA nephropathy. The autoimmune character of the disease is explained by a multihit pathogenesis model, wherein overproduction of aberrantly glycosylated IgA1, galactose-deficient in some O-glycans, by IgA1-secreting cells leads to increased levels of circulatory galactose-deficient IgA1. These glycoforms induce production of autoantibodies that subsequently bind hinge-region of galactose-deficient IgA1 molecules, resulting in the formation of nephritogenic immune complexes. Some of these complexes deposit in the kidney, activate mesangial cells, and incite glomerular injury. Thus, galactose-deficient IgA1 is central to the disease process. In this article, we review studies concerning IgA1 O-glycosylation that have contributed to the current understanding of the role of IgA1 in the pathogenesis of IgA nephropathy.
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Affiliation(s)
- Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL..
| | - Jonathan Barratt
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Bruce A Julian
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL.; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL
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Wu MY, Chen CS, Yiang GT, Cheng PW, Chen YL, Chiu HC, Liu KH, Lee WC, Li CJ. The Emerging Role of Pathogenesis of IgA Nephropathy. J Clin Med 2018; 7:jcm7080225. [PMID: 30127305 PMCID: PMC6112037 DOI: 10.3390/jcm7080225] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 08/12/2018] [Accepted: 08/16/2018] [Indexed: 12/20/2022] Open
Abstract
IgA nephropathy is an autoimmune disease induced by fthe ormation of galactose-deficient IgA1 and anti-glycans autoantibody. A multi-hit hypothesis was promoted to explain full expression of IgA nephropathy. The deposition of immune complex resulted in activation of the complement, increasing oxidative stress, promoting inflammatory cascade, and inducing cell apoptosis via mesangio-podocytic-tubular crosstalk. The interlinked signaling pathways of immune-complex-mediated inflammation can offer a novel target for therapeutic approaches. Treatments of IgA nephropathy are also summarized in our review article. In this article, we provide an overview of the recent basic and clinical studies in cell molecular regulation of IgAN for further treatment interventions.
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Affiliation(s)
- Meng-Yu Wu
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Chien-Sheng Chen
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Giou-Teng Yiang
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Pei-Wen Cheng
- Yuh-Ing Junior College of Health Care & Management, Kaohsiung 807, Taiwan.
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Yu-Long Chen
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Hsiao-Chen Chiu
- Department of Obstetrics and Gynecology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan.
- Department of Obstetrics and Gynecology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Kuan-Hung Liu
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine National Cheng Kung University, Tainan 704, Taiwan.
| | - Wen-Chin Lee
- Division of Nephrology, Department of Internal Medicine, Chang Bing Show Chwan Memorial Hospital, Changhua 505, Taiwan.
| | - Chia-Jung Li
- Research Assistant Center, Show Chwan Memorial Hospital, Changhua 500, Taiwan.
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Reily C, Rizk DV, Julian BA, Novak J. Assay for galactose-deficient IgA1 enables mechanistic studies with primary cells from IgA nephropathy patients. Biotechniques 2018; 65:71-77. [PMID: 30091383 PMCID: PMC6152805 DOI: 10.2144/btn-2018-0042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/19/2018] [Indexed: 11/23/2022] Open
Abstract
AIMS IgA nephropathy, the most common primary glomerulonephritis worldwide, is characterized by glomerular deposition of galactose-deficient IgA1 and elevated serum levels of this IgA1 glycoform. Current ELISA methods lack sensitivity to assess galactose deficiency using small amounts of IgA1, which limits studies in primary cells due to modest IgA1 production in isolated peripheral-blood lymphocytes. METHODS Lectin from Helix pomatia was conjugated to biotin or acridinium ester and used in ELISA to detect galactose deficiency of IgA1 using small amounts of IgA1. RESULTS Lectin conjugated to acridinium had an approximately a log-fold increased sensitivity compared with biotin-labeled lectin. CONCLUSIONS The new method of using lectin from Helix pomatia conjugated to acridinium increased assay sensitivity, allowing future mechanistic studies with cultured primary cells.
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Affiliation(s)
- Colin Reily
- University of Alabama at Birmingham, Department of Medicine, Birmingham, AL, USA
| | - Dana V Rizk
- University of Alabama at Birmingham, Department of Medicine, Birmingham, AL, USA
| | - Bruce A Julian
- University of Alabama at Birmingham, Department of Medicine, Birmingham, AL, USA
- University of Alabama at Birmingham, Department of Microbiology, Birmingham, AL, USA
| | - Jan Novak
- University of Alabama at Birmingham, Department of Microbiology, Birmingham, AL, USA
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44
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Suzuki H. Biomarkers for IgA nephropathy on the basis of multi-hit pathogenesis. Clin Exp Nephrol 2018; 23:26-31. [PMID: 29740706 PMCID: PMC6344607 DOI: 10.1007/s10157-018-1582-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/26/2018] [Indexed: 01/06/2023]
Abstract
IgA nephropathy (IgAN) is the most prevalent glomerular disease worldwide and is associated with a poor prognosis. Development of curative treatment strategies and approaches for early diagnosis is necessary. Renal biopsy is the gold standard for the diagnosis and assessment of disease activity. However, reliable biomarkers are needed for the noninvasive diagnosis of this disease and to more fully delineate the risk of progression. With regard to the pathogenesis of IgAN, the multi-hit hypothesis, including production of galactose-deficient IgA1 (Gd-IgA1; Hit 1), IgG or IgA autoantibodies that recognize Gd-IgA1 (Hit 2), and their subsequent immune complexes formation (Hit 3) and glomerular deposition (Hit 4), has been widely supported by many studies. Although the prognostic values of several biomarkers have been discussed, we recently developed a highly sensitive and specific diagnostic method by measuring serum levels of Gd-IgA1 and Gd-IgA1-containing immune complexes. In addition, urinary Gd-IgA1 may represent a disease-specific biomarker for IgAN. We also confirmed that there is a significant correlation between serum levels of these effector molecules and disease activity, suggesting that each can be considered a practical surrogate marker of therapeutic response. Thus, these disease-oriented specific serum and urine biomarkers may be useful for screening of potential IgAN with isolated hematuria, earlier diagnosis, disease activity, and eventually, response to treatment. In this review, we discuss these concepts, with a focus on potential clinical applications of these biomarkers.
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Affiliation(s)
- Hitoshi Suzuki
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan.
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45
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Yeo SC, Cheung CK, Barratt J. New insights into the pathogenesis of IgA nephropathy. Pediatr Nephrol 2018; 33:763-777. [PMID: 28624979 PMCID: PMC5861174 DOI: 10.1007/s00467-017-3699-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 11/29/2022]
Abstract
IgA nephropathy is the most common form of glomerulonephritis in many parts of the world and remains an important cause of end-stage renal disease. Current evidence suggests that IgA nephropathy is not due to a single pathogenic insult, but rather the result of multiple sequential pathogenic "hits". An abnormally increased level of circulating poorly O-galactosylated IgA1 and the production of O-glycan-specific antibodies leads to the formation of IgA1-containing immune complexes, and their subsequent mesangial deposition results in inflammation and glomerular injury. While this general framework has formed the foundation of our current understanding of the pathogenesis of IgA nephropathy, much work is ongoing to try to precisely define the genetic, epigenetic, immunological, and molecular basis of IgA nephropathy. In particular, the precise origin of poorly O-galactosylated IgA1 and the inciting factors for the production of O-glycan-specific antibodies continue to be intensely evaluated. The mechanisms responsible for mesangial IgA1 deposition and subsequent renal injury also remain incompletely understood. In this review, we summarize the current understanding of the key steps involved in the pathogenesis of IgA nephropathy. It is hoped that further advances in our understanding of this common glomerulonephritis will lead to novel diagnostic and prognostic biomarkers, and targeted therapies to ameliorate disease progression.
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Affiliation(s)
- See Cheng Yeo
- Department of Renal Medicine, Tan Tock Seng Hospital, Singapore, Singapore
| | - Chee Kay Cheung
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, UK
- The John Walls Renal Unit, Leicester General Hospital, Leicester, UK
| | - Jonathan Barratt
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, UK.
- The John Walls Renal Unit, Leicester General Hospital, Leicester, UK.
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46
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López-Mejías R, Castañeda S, Genre F, Remuzgo-Martínez S, Carmona FD, Llorca J, Blanco R, Martín J, González-Gay MA. Genetics of immunoglobulin-A vasculitis (Henoch-Schönlein purpura): An updated review. Autoimmun Rev 2018; 17:301-315. [DOI: 10.1016/j.autrev.2017.11.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 11/16/2017] [Indexed: 12/12/2022]
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47
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Deng H, Ma J, Jing Z, Deng Z, Liang Y, A L, Liu Y, Qiu X, Wang Y. Expression of immunoglobulin A in human mesangial cells and its effects on cell apoptosis and adhesion. Mol Med Rep 2018; 17:5272-5282. [PMID: 29393471 PMCID: PMC5865995 DOI: 10.3892/mmr.2018.8544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 01/30/2018] [Indexed: 12/27/2022] Open
Abstract
IgA nephropathy (IgAN) is characterized by predominant IgA deposition in the glomerular mesangium. It has been considered that the deposited IgA is synthesized by B cells, although recent reports have suggested the implication of other cell types. Therefore, the present study investigated whether glomerular mesangial cells could produce IgA by themselves. Semi‑quantitative reverse transcription-polymerase chain reaction, and immunostaining analysis revealed that the IgA protein and gene transcripts were expressed in primary human renal mesangial cells (HRMCs). Furthermore, the IgA heavy chain (α1 and α2) and the light chain (κ and λ) were localized in the cytoplasm or were located on the cell membranes of human mesangial cells (HMCs). Mass spectrometry results indicated that Ig α1 and Ig α2 were secreted in the culture media of HMCs. The transcripts of Ig α, Ig κ and Ig λ constant regions were detected. The predominant rearrangement pattern of the variable region of Ig κ, was Vκ3‑20*01/Jκ1*01 in HMCs and Vκ1‑12*01/Jκ4*01 in HRMCs. In addition, knockdown of Ig α1 expression by small interfering RNA (siRNA) inhibited cell adhesion and promoted apoptosis. Our findings demonstrate that HMCs can express IgA, and that this expression is associated with cell functions, which may contribute to the deposition of IgA in patients with IgAN.
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Affiliation(s)
- Hui Deng
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Junfan Ma
- Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing 100191, P.R. China
| | - Ziyang Jing
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Zhenling Deng
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Yaoxian Liang
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Lata A
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Yang Liu
- Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing 100191, P.R. China
| | - Xiaoyan Qiu
- Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing 100191, P.R. China
| | - Yue Wang
- Department of Nephrology, Peking University Third Hospital, Beijing 100191, P.R. China
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48
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Serial Galactose-Deficient IgA1 Levels in Children with IgA Nephropathy and Healthy Controls. Int J Nephrol 2017; 2017:8210641. [PMID: 29333295 PMCID: PMC5733148 DOI: 10.1155/2017/8210641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 10/19/2017] [Accepted: 10/29/2017] [Indexed: 12/02/2022] Open
Abstract
Galactose-deficient IgA1 (Gd-IgA1) is a key pathogenic factor for IgA nephropathy (IgAN) and a potential biomarker for the disease. This study examined serial serum Gd-IgA1 levels over 1 year in 13 children with IgAN and 40 healthy children, to determine whether or not serum Gd-IgA1 levels changed over time. Subjects were younger than 18 years of age. Follow-up measurements were scheduled 6 and/or 12 months later. Analysis of variance and regression models for repeated measures were used to estimate group and time effects. Serum Gd-IgA1 level was higher in initial samples for IgAN patients compared to those of healthy children (P < 0.0001). Serum Gd-IgA1 levels did not change over time for healthy controls but increased for IgAN patients (P = 0.001). Serum Gd-IgA1 level was elevated for 9 children with IgAN at study entry and remained elevated. Two of the 4 IgAN patients with initially normal Gd-IgA1 levels had a subsequent elevated level. The persistent elevation of the serum Gd-IgA1 level in children with IgAN enhances its utility as a potential diagnostic test for IgAN.
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49
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Heineke MH, Ballering AV, Jamin A, Ben Mkaddem S, Monteiro RC, Van Egmond M. New insights in the pathogenesis of immunoglobulin A vasculitis (Henoch-Schönlein purpura). Autoimmun Rev 2017; 16:1246-1253. [PMID: 29037908 DOI: 10.1016/j.autrev.2017.10.009] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 08/29/2017] [Indexed: 12/16/2022]
Abstract
Immunoglobulin A vasculitis (IgAV), also referred to as Henoch-Schönlein purpura, is the most common form of childhood vasculitis. The pathogenesis of IgAV is still largely unknown. The disease is characterized by IgA1-immune deposits, complement factors and neutrophil infiltration, which is accompanied with vascular inflammation. Incidence of IgAV is twice as high during fall and winter, suggesting an environmental trigger associated to climate. Symptoms can resolve without intervention, but some patients develop glomerulonephritis with features similar to IgA nephropathy that include hematuria, proteinuria and IgA deposition in the glomerulus. Ultimately, this can lead to end-stage renal disease. In IgA nephropathy immune complexes containing galactose-deficient (Gd-)IgA1 are found and thought to play a role in pathogenesis. Although Gd-IgA1 complexes are also present in patients with IgAV with nephritis, their role in IgAV is disputed. Alternatively, it has been proposed that in IgAV IgA1 antibodies are generated against endothelial cells. We anticipate that such IgA complexes can activate neutrophils via the IgA Fc receptor FcαRI (CD89), thereby inducing neutrophil migration and activation, which ultimately causes tissue damage in IgAV. In this Review, we discuss the putative role of IgA, IgA receptors, neutrophils and other factors such as infections, genetics and the complement system in the pathogenesis of IgA vasculitis.
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Affiliation(s)
- Marieke H Heineke
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, De Boelelaan 1109, 1081 HZ Amsterdam, The Netherlands; Amsterdam Infection & Immunity Institute, Amsterdam, The Netherlands
| | - Aranka V Ballering
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, De Boelelaan 1109, 1081 HZ Amsterdam, The Netherlands; Amsterdam Infection & Immunity Institute, Amsterdam, The Netherlands
| | - Agnès Jamin
- National French Institute of Health and Medical Research (INSERM) U1149, Centre de Recherche Sur l'Inflammation, 16 Rue Henri Huchard, Paris 75018, France; National French Center of Scientific Research (CNRS) ERL8252, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 16 Rue Henri Huchard, Paris 75018, France; Laboratory of Inflamex Excellency, Faculty of Medicine, Xavier Bichat Site, Paris, France
| | - Sanae Ben Mkaddem
- National French Institute of Health and Medical Research (INSERM) U1149, Centre de Recherche Sur l'Inflammation, 16 Rue Henri Huchard, Paris 75018, France; National French Center of Scientific Research (CNRS) ERL8252, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 16 Rue Henri Huchard, Paris 75018, France; Laboratory of Inflamex Excellency, Faculty of Medicine, Xavier Bichat Site, Paris, France
| | - Renato C Monteiro
- National French Institute of Health and Medical Research (INSERM) U1149, Centre de Recherche Sur l'Inflammation, 16 Rue Henri Huchard, Paris 75018, France; National French Center of Scientific Research (CNRS) ERL8252, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 16 Rue Henri Huchard, Paris 75018, France; Laboratory of Inflamex Excellency, Faculty of Medicine, Xavier Bichat Site, Paris, France
| | - Marjolein Van Egmond
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, De Boelelaan 1109, 1081 HZ Amsterdam, The Netherlands; Amsterdam Infection & Immunity Institute, Amsterdam, The Netherlands; Department of Surgery, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
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50
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Krochmal M, Cisek K, Filip S, Markoska K, Orange C, Zoidakis J, Gakiopoulou C, Spasovski G, Mischak H, Delles C, Vlahou A, Jankowski J. Identification of novel molecular signatures of IgA nephropathy through an integrative -omics analysis. Sci Rep 2017; 7:9091. [PMID: 28831120 PMCID: PMC5567309 DOI: 10.1038/s41598-017-09393-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/26/2017] [Indexed: 12/19/2022] Open
Abstract
IgA nephropathy (IgAN) is the most prevalent among primary glomerular diseases worldwide. Although our understanding of IgAN has advanced significantly, its underlying biology and potential drug targets are still unexplored. We investigated a combinatorial approach for the analysis of IgAN-relevant -omics data, aiming at identification of novel molecular signatures of the disease. Nine published urinary proteomics datasets were collected and the reported differentially expressed proteins in IgAN vs. healthy controls were integrated into known biological pathways. Proteins participating in these pathways were subjected to multi-step assessment, including investigation of IgAN transcriptomics datasets (Nephroseq database), their reported protein-protein interactions (STRING database), kidney tissue expression (Human Protein Atlas) and literature mining. Through this process, from an initial dataset of 232 proteins significantly associated with IgAN, 20 pathways were predicted, yielding 657 proteins for further analysis. Step-wise evaluation highlighted 20 proteins of possibly high relevance to IgAN and/or kidney disease. Experimental validation of 3 predicted relevant proteins, adenylyl cyclase-associated protein 1 (CAP1), SHC-transforming protein 1 (SHC1) and prolylcarboxypeptidase (PRCP) was performed by immunostaining of human kidney sections. Collectively, this study presents an integrative procedure for -omics data exploitation, giving rise to biologically relevant results.
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Affiliation(s)
- Magdalena Krochmal
- Biomedical Research Foundation Academy of Athens, Center of Basic Research, Athens, Greece
- RWTH Aachen University Hospital, Institute for Molecular Cardiovascular Research, Aachen, Germany
| | | | - Szymon Filip
- Biomedical Research Foundation Academy of Athens, Center of Basic Research, Athens, Greece
| | - Katerina Markoska
- Department of Nephrology, Medical Faculty, University of Skopje, Skopje, Macedonia
| | - Clare Orange
- Department of Pathology, School of Medicine, University of Glasgow, Glasgow, UK
| | - Jerome Zoidakis
- Biomedical Research Foundation Academy of Athens, Center of Basic Research, Athens, Greece
| | - Chara Gakiopoulou
- Pathology Department, National and Kapodistrian University of Athens, Athens, Greece
| | - Goce Spasovski
- Department of Nephrology, Medical Faculty, University of Skopje, Skopje, Macedonia
| | - Harald Mischak
- Mosaiques Diagnostics GmbH, Hannover, Germany
- University of Glasgow, Institute of Cardiovascular and Medical Sciences, Glasgow, UK
| | - Christian Delles
- Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK
| | - Antonia Vlahou
- Biomedical Research Foundation Academy of Athens, Center of Basic Research, Athens, Greece.
| | - Joachim Jankowski
- RWTH Aachen University Hospital, Institute for Molecular Cardiovascular Research, Aachen, Germany.
- University of Maastricht, CARIM School for Cardiovascular Diseases, Maastricht, Netherlands.
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