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Birgersson PS, Chahal AS, Klau LJ, Holte HB, Arlov Ø, Aachmann FL. Structural characterization and immunomodulating assessment of ultra-purified water extracted fucoidans from Saccharina latissima, Alaria esculenta and Laminaria hyperborea. Carbohydr Polym 2024; 343:122448. [PMID: 39174088 DOI: 10.1016/j.carbpol.2024.122448] [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: 04/26/2024] [Revised: 06/19/2024] [Accepted: 06/27/2024] [Indexed: 08/24/2024]
Abstract
Fucoidans, a group of high molecular weight polysaccharides derived mainly from brown algae, are characterized by their high fucose content, degree of sulfation (DS), and intra- and interspecific structural variation. Fucoidans are increasingly recognized due to various reported bioactivities, potentially beneficial for human health. To unlock their potential use within biomedical applications, a better understanding of their structure-functional relationship is needed. To achieve this, systematic bioactivity studies based on well-defined, pure fucoidans, and the establishment of standardized, satisfactory purification protocols are required. We performed a comprehensive compositional and structural characterization of crude and ultra-purified fucoidans from three kelps: Saccharina latissima (SL), Alaria esculenta (AE) and Laminaria hyperborea (LH). Further, the complement-inhibiting activity of the purified fucoidans was assessed in a human whole blood model. The purification process led to fucoidans with higher DS and fucose and lower concentrations of other monosaccharides. Fucoidans from SL and LH resembles homofucans, while AE is a heterofucan rich in galactose with comparably lower DS. Fucoidans from SL and LH showed complement-inhibiting activity in blood and blood plasma, while no inhibition was observed for AE under the same conditions. The results emphasize the importance of high DS and possibly fucose content for fucoidans' bioactive properties.
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Affiliation(s)
- Paulina S Birgersson
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway.
| | - Aman S Chahal
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway.
| | - Leesa J Klau
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway; Department of Process Technology, SINTEF Industry, Forskningsveien 1, 0373 Oslo, Norway.
| | - Helle Bratsberg Holte
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway
| | - Øystein Arlov
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway.
| | - Finn L Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway.
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2
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Alkaff FF, Lammerts RGM, Daha MR, Berger SP, van den Born J. Apical tubular complement activation and the loss of kidney function in proteinuric kidney diseases. Clin Kidney J 2024; 17:sfae215. [PMID: 39135935 PMCID: PMC11318052 DOI: 10.1093/ckj/sfae215] [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: 03/07/2024] [Indexed: 08/15/2024] Open
Abstract
Many kidney diseases are associated with proteinuria. Since proteinuria is independently associated with kidney function loss, anti-proteinuric medication, often in combination with dietary salt restriction, comprises a major cornerstone in the prevention of progressive kidney failure. Nevertheless, complete remission of proteinuria is very difficult to achieve, and most patients with persistent proteinuria slowly progress toward kidney failure. It is well-recognized that proteinuria leads to kidney inflammation and fibrosis via various mechanisms. Among others, complement activation at the apical side of the proximal tubular epithelial cells is suggested to play a crucial role as a cause of progressive loss of kidney function. However, hitherto limited attention is given to the pathophysiological role of tubular complement activation relative to glomerular complement activation. This review aims to summarize the evidence for tubular epithelial complement activation in proteinuric kidney diseases in relation to loss of kidney function.
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Affiliation(s)
- Firas F Alkaff
- Division of Nephrology, Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Division of Pharmacology and Therapy, Department of Anatomy, Histology, and Pharmacology, Faculty of Medicine Universitas Airlangga, Surabaya, Indonesia
| | - Rosa G M Lammerts
- Transplantation Immunology, Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Mohamed R Daha
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Stefan P Berger
- Division of Nephrology, Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jacob van den Born
- Division of Nephrology, Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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3
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Campeiro JD, Dam WA, Hayashi MAF, van den Born J. Crotamine/siRNA Nanocomplexes for Functional Downregulation of Syndecan-1 in Renal Proximal Tubular Epithelial Cells. Pharmaceutics 2023; 15:1576. [PMID: 37376025 DOI: 10.3390/pharmaceutics15061576] [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: 01/31/2023] [Revised: 05/09/2023] [Accepted: 05/16/2023] [Indexed: 06/29/2023] Open
Abstract
Proteinuria drives progressive tubulointerstitial fibrosis in native and transplanted kidneys, mainly through the activation of proximal tubular epithelial cells (PTECs). During proteinuria, PTEC syndecan-1 functions as a docking platform for properdin-mediated alternative complement activation. Non-viral gene delivery vectors to target PTEC syndecan-1 could be useful to slow down alternative complement activation. In this work, we characterize a PTEC-specific non-viral delivery vector composed of the cell-penetrating peptide crotamine complexed with a syndecan-1 targeting siRNA. Cell biological characterization was performed in the human PTEC HK2 cell line, using confocal microscopy, qRT-PCR, and flow cytometry. PTEC targeting in vivo was carried out in healthy mice. Crotamine/siRNA nanocomplexes are positively charged, about 100 nm in size, resistant to nuclease degradation, and showed in vitro and in vivo specificity and internalization into PTECs. The efficient suppression of syndecan-1 expression in PTECs mediated by these nanocomplexes significantly reduced properdin binding (p < 0.001), as well as the subsequent complement activation by the alternative complement pathway (p < 0.001), as observed in either normal or activated tubular conditions. To conclude, crotamine/siRNA-mediated downregulation of PTEC syndecan-1 reduced the activation of the alternative complement pathway. Therefore, we suggest that the present strategy opens new venues for targeted proximal tubular gene therapy in renal diseases.
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Affiliation(s)
- Joana D'Arc Campeiro
- Department Nephrology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, De Brug, 4th Floor, AA53, 9713 GZ Groningen, The Netherlands
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Rua 3 de Maio 100, Ed. INFAR, 3rd Floor, São Paulo 04044-020, Brazil
| | - Wendy A Dam
- Department Nephrology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, De Brug, 4th Floor, AA53, 9713 GZ Groningen, The Netherlands
| | - Mirian A F Hayashi
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Rua 3 de Maio 100, Ed. INFAR, 3rd Floor, São Paulo 04044-020, Brazil
| | - Jacob van den Born
- Department Nephrology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, De Brug, 4th Floor, AA53, 9713 GZ Groningen, The Netherlands
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4
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Pisarenka S, Meyer NC, Xiao X, Goodfellow R, Nester CM, Zhang Y, Smith RJH. Modeling C3 glomerulopathies: C3 convertase regulation on an extracellular matrix surface. Front Immunol 2023; 13:1073802. [PMID: 36846022 PMCID: PMC9947773 DOI: 10.3389/fimmu.2022.1073802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023] Open
Abstract
Introduction C3 glomerulopathies (C3G) are ultra-rare complement-mediated diseases that lead to end-stage renal disease (ESRD) within 10 years of diagnosis in ~50% of patients. Overactivation of the alternative pathway (AP) of complement in the fluid phase and on the surface of the glomerular endothelial glycomatrix is the underlying cause of C3G. Although there are animal models for C3G that focus on genetic drivers of disease, in vivo studies of the impact of acquired drivers are not yet possible. Methods Here we present an in vitro model of AP activation and regulation on a glycomatrix surface. We use an extracellular matrix substitute (MaxGel) as a base upon which we reconstitute AP C3 convertase. We validated this method using properdin and Factor H (FH) and then assessed the effects of genetic and acquired drivers of C3G on C3 convertase. Results We show that C3 convertase readily forms on MaxGel and that this formation was positively regulated by properdin and negatively regulated by FH. Additionally, Factor B (FB) and FH mutants impaired complement regulation when compared to wild type counterparts. We also show the effects of C3 nephritic factors (C3Nefs) on convertase stability over time and provide evidence for a novel mechanism of C3Nef-mediated C3G pathogenesis. Discussion We conclude that this ECM-based model of C3G offers a replicable method by which to evaluate the variable activity of the complement system in C3G, thereby offering an improved understanding of the different factors driving this disease process.
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Affiliation(s)
- Sofiya Pisarenka
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
- Molecular Medicine Graduate Program, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Nicole C. Meyer
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Xue Xiao
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Renee Goodfellow
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Carla M. Nester
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Yuzhou Zhang
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Richard J. H. Smith
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
- Molecular Medicine Graduate Program, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
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5
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van Essen MF, Schlagwein N, van Gijlswijk-Janssen DJ, Ruben JM, van Kooten C. Properdin produced by dendritic cells contributes to the activation of T cells. Immunobiology 2022; 227:152246. [PMID: 35843030 DOI: 10.1016/j.imbio.2022.152246] [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: 12/21/2021] [Revised: 06/01/2022] [Accepted: 07/06/2022] [Indexed: 11/05/2022]
Abstract
The complement system does not only play an important role in the defence against microorganism and pathogens, but also contributes to the regulation of innate and adaptive immunity. Especially activation fragments C3a and C5a and complement activation at the interface of antigen presenting cell (APC) and T cell, were shown to have a role in T cell activation and proliferation. Whereas most complement factors are produced by the liver, properdin, a positive regulator of the C3 convertase, is mainly produced by myeloid cells. Here we show that properdin can be detected in myeloid cell infiltrate during human renal allograft rejection. In vitro, properdin is produced and secreted by human immature dendritic cells (iDCs), which is further increased by CD40-L-matured DCs (mDCs). Transfection with a specific properdin siRNA reduced properdin secretion by iDCs and mDCs, without affecting the expression of co-stimulatory markers CD80 and CD86. Co-culture of properdin siRNA-transfected iDCs and mDCs with human allogeneic T cells resulted in reduced T cell proliferation, especially under lower DC-T cell ratio's (1:30 and 1:90 ratio). In addition, T cell cytokines were altered, including a reduced TNF-α and IL-17 secretion by T cells co-cultured with properdin siRNA-transfected iDCs. Taken together, these results indicate a local role for properdin during the interaction of DCs and allogeneic T cells, contributing to the shaping of T cell proliferation and activation.
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Affiliation(s)
- Mieke F van Essen
- Div of Nephrology and Transplant Medicine, Dept. of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Nicole Schlagwein
- Div of Nephrology and Transplant Medicine, Dept. of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Jurjen M Ruben
- Div of Nephrology and Transplant Medicine, Dept. of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Cees van Kooten
- Div of Nephrology and Transplant Medicine, Dept. of Medicine, Leiden University Medical Center, Leiden, The Netherlands.
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- Div of Nephrology and Transplant Medicine, Dept. of Medicine, Leiden University Medical Center, Leiden, The Netherlands
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6
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Fakhouri F, Schwotzer N, Golshayan D, Frémeaux-Bacchi V. The Rational Use of Complement Inhibitors in Kidney Diseases. Kidney Int Rep 2022; 7:1165-1178. [PMID: 35685323 PMCID: PMC9171628 DOI: 10.1016/j.ekir.2022.02.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 12/14/2022] Open
Abstract
The development of complement inhibitors represented one of the major breakthroughs in clinical nephrology in the last decade. Complement inhibition has dramatically transformed the outcome of one of the most severe kidney diseases, the atypical hemolytic uremic syndrome (aHUS), a prototypic complement-mediated disorder. The availability of complement inhibitors has also opened new promising perspectives for the management of several other kidney diseases in which complement activation is involved to a variable extent. With the rapidly growing number of complement inhibitors tested in a rapidly increasing number of indications, a rational use of this innovative and expensive new therapeutic class has become crucial. The present review aims to summarize what we know, and what we still ignore, regarding complement activation and therapeutic inhibition in kidney diseases. It also provides some clues and elements of thoughts for a rational approach of complement modulation in kidney diseases.
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Affiliation(s)
- Fadi Fakhouri
- Service de Néphrologie et d'hypertension, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
| | - Nora Schwotzer
- Service de Néphrologie et d'hypertension, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
| | - Déla Golshayan
- Centre de Transplantation d'organes, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie, Paris University, Paris, France
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7
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Cortes C, Desler C, Mazzoli A, Chen JY, Ferreira VP. The role of properdin and Factor H in disease. Adv Immunol 2022; 153:1-90. [PMID: 35469595 DOI: 10.1016/bs.ai.2021.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.
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Affiliation(s)
- Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States.
| | - Caroline Desler
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Amanda Mazzoli
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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8
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Essen MF, Schlagwein N, den Hoven EM, Gijlswijk‐Janssen DJ, Lubbers R, den Bos RM, den Born J, Ruben JM, Trouw LA, Kooten C. Initial properdin binding contributes to alternative pathway activation at the surface of viable and necrotic cells. Eur J Immunol 2022; 52:597-608. [PMID: 35092629 PMCID: PMC9303752 DOI: 10.1002/eji.202149259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 12/01/2021] [Accepted: 01/10/2022] [Indexed: 11/16/2022]
Abstract
Properdin, the only known positive regulator of the complement system, stabilizes the C3 convertase, thereby increasing its half‐life. In contrast to most other complement factors, properdin is mainly produced extrahepatically by myeloid cells. Recent data suggest a role for properdin as a pattern recognition molecule. Here, we confirmed previous findings of properdin binding to different necrotic cells including Jurkat T cells. Binding can occur independent of C3, as demonstrated by HAP‐1 C3 KO cells, excluding a role for endogenous C3. In view of the cellular source of properdin, interaction with myeloid cells was examined. Properdin bound to the surface of viable monocyte‐derived pro‐ and anti‐inflammatory macrophages, but not to DCs. Binding was demonstrated for purified properdin as well as fractionated P2, P3, and P4 properdin oligomers. Binding contributed to local complement activation as determined by C3 and C5b‐9 deposition on the cell surfaces and seems a prerequisite for alternative pathway activation. Interaction of properdin with cell surfaces could be inhibited with the tick protein Salp20 and by different polysaccharides, depending on sulfation and chain length. These data identify properdin as a factor interacting with different cell surfaces, being either dead or alive, contributing to the local stimulation of complement activation.
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Affiliation(s)
- Mieke F. Essen
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
| | - Nicole Schlagwein
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
| | - Elisa M.P. den Hoven
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
| | - Daniëlle J. Gijlswijk‐Janssen
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
| | - Rosalie Lubbers
- Department of Rheumatology Leiden University Medical Center Leiden The Netherlands
| | - Ramon M. den Bos
- Crystal and Structural Chemistry Bijvoet Center for Biomolecular Research Department of Chemistry Faculty of Science Utrecht University Utrecht The Netherlands
| | - Jacob den Born
- Department of Nephrology University Medical Center Groningen Groningen The Netherlands
| | - Jurjen M. Ruben
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
| | - Leendert A. Trouw
- Department of Rheumatology Leiden University Medical Center Leiden The Netherlands
- Department of Immunology Leiden University Medical Center Leiden The Netherlands
| | - Cees Kooten
- Div. of Nephrology and Transplant Medicine Dept. of Medicine Leiden University Medical Center Leiden The Netherlands
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9
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Loeven MA, Maciej-Hulme ML, Yanginlar C, Hubers MC, Kellenbach E, de Graaf M, van Kuppevelt TH, Wetzels J, Rabelink TJ, Smith RJH, van der Vlag J. Selective Binding of Heparin/Heparan Sulfate Oligosaccharides to Factor H and Factor H-Related Proteins: Therapeutic Potential for C3 Glomerulopathies. Front Immunol 2021; 12:676662. [PMID: 34489931 PMCID: PMC8416517 DOI: 10.3389/fimmu.2021.676662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 08/02/2021] [Indexed: 11/26/2022] Open
Abstract
Complement dysregulation is characteristic of the renal diseases atypical hemolytic uremic syndrome (aHUS) and complement component 3 glomerulopathy (C3G). Complement regulatory protein Factor H (FH) inhibits complement activity, whereas FH-related proteins (FHRs) lack a complement regulatory domain. FH and FHRs compete for binding to host cell glycans, in particular heparan sulfates (HS). HS is a glycosaminoglycan with an immense structural variability, where distinct sulfation patterns mediate specific binding of proteins. Mutations in FH, FHRs, or an altered glomerular HS structure may disturb the FH : FHRs balance on glomerular endothelial cells, thereby leading to complement activation and the subsequent development of aHUS/C3G. In this study, we aimed to identify specific HS structures that could specifically compete off FHRs from HS glycocalyx (HSGlx), without interfering with FH binding. FH/FHR binding to human conditionally immortalized glomerular endothelial cells (ciGEnCs) and HSGlx purified from ciGEnC glycocalyx was assessed. HS modifications important for FH/FHR binding to HSGlx were analyzed using selectively desulfated heparins in competition with purified HSGlx. We further assessed effects of heparinoids on FHR1- and FHR5-mediated C3b deposition on ciGEnCs. In the presence of C3b, binding of FH, FHR1 and FHR5 to ciGEnCs was significantly increased, whereas binding of FHR2 was minimal. FHR1 and 5 competitively inhibited FH binding to HSGlx, leading to alternative pathway dysregulation. FHR1 and FHR5 binding was primarily mediated by N-sulfation while FH binding depended on N-, 2-O- and 6-O-sulfation. Addition of 2-O-desulfated heparin significantly reduced FHR1- and FHR5-mediated C3b deposition on ciGEnCs. We identify 2-O-desulfated heparin derivatives as potential therapeutics for C3G and other diseases with dysregulated complement.
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Affiliation(s)
- Markus A Loeven
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Marissa L Maciej-Hulme
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Cansu Yanginlar
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Melanie C Hubers
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Mark de Graaf
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jack Wetzels
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Ton J Rabelink
- Department of Nephrology and Einthoven Laboratory for Vascular Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Richard J H Smith
- Departments of Internal Medicine and Otolaryngology, Carver College of Medicine, Iowa City, IA, United States
| | - Johan van der Vlag
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
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10
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Shrestha P, Yazdani S, Vivès RR, El Masri R, Dam W, van de Sluis B, van den Born J. Proteinuria converts hepatic heparan sulfate to an effective proprotein convertase subtilisin kexin type 9 enzyme binding partner. Kidney Int 2021; 99:1369-1381. [PMID: 33609572 DOI: 10.1016/j.kint.2021.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 01/06/2021] [Accepted: 01/14/2021] [Indexed: 12/22/2022]
Abstract
Hepatic uptake of triglyceride-rich remnant lipoproteins is mediated by the low-density lipoprotein receptor, a low-density lipoprotein receptor related protein and the heparan sulfate proteoglycan, syndecan-1. Heparan sulfate proteoglycan also mediates low-density lipoprotein receptor degradation by a regulator of cholesterol homeostasis, proprotein convertase subtilisin kexin type 9 (PCSK9), thereby hampering triglyceride-rich remnant lipoproteins uptake. In this study, we investigated the effects of proteinuria on PCSK9, hepatic heparan sulfate proteoglycan and plasma triglyceride-rich remnant lipoproteins. Adriamycin-injected rats developed proteinuria, elevated triglycerides and total cholesterol (all significantly increased). Proteinuria associated with triglycerides and total cholesterol and serum PCSK9 (all significant associations) without loss of the low-density lipoprotein receptor as evidenced by immunofluorescence staining and western blotting. In proteinuric rats, PCSK9 accumulated in sinusoids, whereas in control rats PCSK9 was localized in the cytoplasm of hepatocytes. Molecular profiling revealed that the heparan sulfate side chains of heparan sulfate proteoglycan to be hypersulfated in proteinuric rats. Competition assays revealed sulfation to be a major determinant for PCSK9 binding. PCSK9 partly colocalized with hypersulfated heparan sulfate in proteinuric rats, but not in control rats. Hence, proteinuria induces hypersulfated hepatic heparan sulfate proteoglycans, increasing their affinity to PCSK9. This might impair hepatic triglyceride-rich remnant lipoproteins uptake, causing proteinuria-associated dyslipidemia. Thus, our study reveals PCSK9/heparan sulfate may be a novel target to control dyslipidemia.
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Affiliation(s)
- Pragyi Shrestha
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Saleh Yazdani
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium; Vlaams Institute of Biotechnology Leuven Center for Microbiology, Leuven, Belgium
| | - Romain R Vivès
- University Grenoble Alpes, Institute of Structural Biology (IBS), Atomic Energy and Alternative Energies Commission (CEA), French National Centre for Scientific Research (CNRS), Grenoble, France
| | - Rana El Masri
- University Grenoble Alpes, Institute of Structural Biology (IBS), Atomic Energy and Alternative Energies Commission (CEA), French National Centre for Scientific Research (CNRS), Grenoble, France
| | - Wendy Dam
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Bart van de Sluis
- Department of Pediatrics, Section Molecular Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Jacob van den Born
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
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11
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Zhang J, Song L, Pedersen DV, Li A, Lambris JD, Andersen GR, Mollnes TE, Ma YJ, Garred P. Soluble collectin-12 mediates C3-independent docking of properdin that activates the alternative pathway of complement. eLife 2020; 9:60908. [PMID: 32909942 PMCID: PMC7511233 DOI: 10.7554/elife.60908] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/09/2020] [Indexed: 01/11/2023] Open
Abstract
Properdin stabilizes the alternative C3 convertase (C3bBb), whereas its role as pattern-recognition molecule mediating complement activation is disputed for decades. Previously, we have found that soluble collectin-12 (sCL-12) synergizes complement alternative pathway (AP) activation. However, whether this observation is C3 dependent is unknown. By application of the C3-inhibitor Cp40, we found that properdin in normal human serum bound to Aspergillus fumigatus solely in a C3b-dependent manner. Cp40 also prevented properdin binding when properdin-depleted serum reconstituted with purified properdin was applied, in analogy with the findings achieved by C3-depleted serum. However, when opsonized with sCL-12, properdin bound in a C3-independent manner exclusively via its tetrameric structure and directed in situ C3bBb assembly. In conclusion, a prerequisite for properdin binding and in situ C3bBb assembly was the initial docking of sCL-12. This implies a new important function of properdin in host defense bridging pattern recognition and specific AP activation.
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Affiliation(s)
- Jie Zhang
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacy, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Lihong Song
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Pharmaceutical Science, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Anna Li
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacy, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Tom Eirik Mollnes
- Department of Immunology, Oslo University Hospital, and University of Oslo, Oslo, Norway.,Research Laboratory, Nordland Hospital, K. G. Jebsen TREC, University of Tromsø, Bodø, Norway.,Center of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ying Jie Ma
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Garred
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Lammerts RGM, Talsma DT, Dam WA, Daha MR, Seelen MAJ, Berger SP, van den Born J. Properdin Pattern Recognition on Proximal Tubular Cells Is Heparan Sulfate/Syndecan-1 but Not C3b Dependent and Can Be Blocked by Tick Protein Salp20. Front Immunol 2020; 11:1643. [PMID: 32849563 PMCID: PMC7426487 DOI: 10.3389/fimmu.2020.01643] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/19/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction: Proteinuria contributes to progression of renal damage, partly by complement activation on proximal tubular epithelial cells. By pattern recognition, properdin has shown to bind to heparan sulfate proteoglycans on tubular epithelium and can initiate the alternative complement pathway (AP). Properdin however, also binds to C3b(Bb) and properdin binding to tubular cells might be influenced by the presence of C3b(Bb) on tubular cells and/or by variability in properdin proteins in vitro. In this study we carefully evaluated the specificity of the properdin – heparan sulfate interaction and whether this interaction could be exploited in order to block alternative complement activation. Methods: Binding of various properdin preparations to proximal tubular epithelial cells (PTEC) and subsequent AP activation was determined in the presence or absence of C3 inhibitor Compstatin and properdin inhibitor Salp20. Heparan sulfate proteoglycan dependency of the pattern recognition of properdin was evaluated on PTEC knocked down for syndecan-1 by shRNA technology. Solid phase binding assays were used to evaluate the effectivity of heparin(oids) and recombinant Salp20 to block the pattern recognition of properdin. Results: Binding of serum-derived and recombinant properdin preparations to PTECs could be dose-dependently inhibited (P < 0.01) and competed off (P < 0.01) by recombinant Salp20 (IC50: ~125 ng/ml) but not by Compstatin. Subsequent properdin-mediated AP activation on PTECs could be inhibited by Compstatin (P < 0.01) and blocked by recombinant Salp20 (P < 0.05). Syndecan-1 deficiency in PTECs resulted in a ~75% reduction of properdin binding (P = 0.057). In solid-phase binding assays, properdin binding to C3b could be dose-dependently inhibited by recombinant Salp20> heparin(oid) > C3b. Discussion: In this study we showed that all properdin preparations recognize heparan sulfate/syndecan-1 on PTECs with and without Compstatin C3 blocking conditions. In contrast to Compstatin, recombinant Salp20 prevents heparan sulfate pattern recognition by properdin on PTECs. Both complement inhibitors prevented properdin-mediated C3 activation. Binding of properdin to C3b could also be blocked by heparin(oids) and recombinant Salp20. This work indicates that properdin serves as a docking station for AP activation on PTECs and a Salp20 analog or heparinoids may be viable inhibitors in properdin mediated AP activation.
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Affiliation(s)
- Rosa G M Lammerts
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Ditmer T Talsma
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Wendy A Dam
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Mohamed R Daha
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Marc A J Seelen
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Stefan P Berger
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jacob van den Born
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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13
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Talsma DT, Poppelaars F, Dam W, Meter-Arkema AH, Vivès RR, Gál P, Boons GJ, Chopra P, Naggi A, Seelen MA, Berger SP, Daha MR, Stegeman CA, van den Born J. MASP-2 Is a Heparin-Binding Protease; Identification of Blocking Oligosaccharides. Front Immunol 2020; 11:732. [PMID: 32425936 PMCID: PMC7212410 DOI: 10.3389/fimmu.2020.00732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 03/31/2020] [Indexed: 12/30/2022] Open
Abstract
It is well-known that heparin and other glycosaminoglycans (GAGs) inhibit complement activation. It is however not known whether fractionation and/or modification of GAGs might deliver pathway-specific inhibition of the complement system. Therefore, we evaluated a library of GAGs and their derivatives for their functional pathway specific complement inhibition, including the MASP-specific C4 deposition assay. Interaction of human MASP-2 with heparan sulfate/heparin was evaluated by surface plasmon resonance, ELISA and in renal tissue. In vitro pathway-specific complement assays showed that highly sulfated GAGs inhibited all three pathways of complement. Small heparin- and heparan sulfate-derived oligosaccharides were selective inhibitors of the lectin pathway (LP). These small oligosaccharides showed identical inhibition of the ficolin-3 mediated LP activation, failed to inhibit the binding of MBL to mannan, but inhibited C4 cleavage by MASPs. Hexa- and pentasulfated tetrasaccharides represent the smallest MASP inhibitors both in the functional LP assay as well in the MASP-mediated C4 assay. Surface plasmon resonance showed MASP-2 binding with heparin and heparan sulfate, revealing high Kon and Koff rates resulted in a Kd of ~2 μM and confirmed inhibition by heparin-derived tetrasaccharide. In renal tissue, MASP-2 partially colocalized with agrin and heparan sulfate, but not with activated C3, suggesting docking, storage, and potential inactivation of MASP-2 by heparan sulfate in basement membranes. Our data show that highly sulfated GAGs mediated inhibition of all three complement pathways, whereas short heparin- and heparan sulfate-derived oligosaccharides selectively blocked the lectin pathway via MASP-2 inhibition. Binding of MASP-2 to immobilized heparan sulfate/heparin and partial co-localization of agrin/heparan sulfate with MASP, but not C3b, might suggest that in vivo heparan sulfate proteoglycans act as a docking platform for MASP-2 and possibly prevent the lectin pathway from activation.
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Affiliation(s)
- Ditmer T Talsma
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Felix Poppelaars
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Wendy Dam
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Anita H Meter-Arkema
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | | | - Peter Gál
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Geert-Jan Boons
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Pradeep Chopra
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | | | - Marc A Seelen
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Stephan P Berger
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Mohamed R Daha
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Coen A Stegeman
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
| | - Jacob van den Born
- Department of Nephrology, University Medical Center Groningen, Groningen, Netherlands
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14
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Radanova M, Mihaylova G, Ivanova D, Daugan M, Lazarov V, Roumenina L, Vasilev V. Clinical and functional consequences of anti-properdin autoantibodies in patients with lupus nephritis. Clin Exp Immunol 2020; 201:135-144. [PMID: 32306375 DOI: 10.1111/cei.13443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/18/2022] Open
Abstract
Properdin is the only positive regulator of the complement system. In this study, we characterize the prevalence, functional consequences and disease associations of autoantibodies against properdin in a cohort of patients with autoimmune disease systemic lupus erythematosus (SLE) suffering from lupus nephritis (LN). We detected autoantibodies against properdin in plasma of 22·5% of the LN patients (16 of 71) by enzyme-linked immunosorbent assay (ELISA). The binding of these autoantibodies to properdin was dose-dependent and was validated by surface plasmon resonance. Higher levels of anti-properdin were related to high levels of anti-dsDNA and anti-nuclear antibodies and low concentrations of C3 and C4 in patients, and also with histological signs of LN activity and chronicity. The high negative predictive value (NPV) of anti-properdin and anti-dsDNA combination suggested that patients who are negative for both anti-properdin and anti-dsDNA will not have severe nephritis. Immunoglobulin G from anti-properdin-positive patients' plasma increased the C3b deposition on late apoptotic cells by flow cytometry. Nevertheless, these IgGs did not modify substantially the binding of properdin to C3b, the C3 convertase C3bBb and the pro-convertase C3bB, evaluated by surface plasmon resonance. In conclusion, anti-properdin autoantibodies exist in LN patients. They have weak but relevant functional consequences, which could have pathological significance.
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Affiliation(s)
- M Radanova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University of Varna, Varna, Bulgaria
| | - G Mihaylova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University of Varna, Varna, Bulgaria
| | - D Ivanova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University of Varna, Varna, Bulgaria
| | - M Daugan
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université de Paris, Paris, France
| | - V Lazarov
- Clinic of Nephrology, University Hospital "Tzaritza Yoanna, ISUL", Medical University of Sofia, Sofia, Bulgaria
| | - L Roumenina
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université de Paris, Paris, France
| | - V Vasilev
- Clinic of Nephrology, University Hospital "Tzaritza Yoanna, ISUL", Medical University of Sofia, Sofia, Bulgaria
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15
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van Essen MF, Ruben JM, de Vries APJ, van Kooten C. Role of properdin in complement-mediated kidney diseases. Nephrol Dial Transplant 2020; 34:742-750. [PMID: 30053164 DOI: 10.1093/ndt/gfy233] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Indexed: 12/15/2022] Open
Abstract
As part of the innate immune system, the complement system is an important mechanism in our first line of defence, but it can also contribute to the onset of various diseases. In renal diseases, the dysregulation of the complement system is often caused by mutations in-and autoantibodies directed against-members of the complement system, and contributes to disease onset and severity. As the only known positive regulator of the complement system, the role of properdin in complement-mediated diseases is largely unknown. In this review, we provide an overview of the detection of properdin in kidney biopsies and urine, serum or plasma samples from patients with complement-mediated renal diseases, such as immune complex-mediated glomerulonephritis and C3 glomerulopathy. Advances towards a better understanding of the role of properdin in (local) complement activation will provide insight into its potential role and offer opportunities to improve diagnosis and therapeutic interventions.
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Affiliation(s)
- Mieke F van Essen
- Division of Nephrology and Transplant Medicine, Department Of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Jurjen M Ruben
- Division of Nephrology and Transplant Medicine, Department Of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Aiko P J de Vries
- Division of Nephrology and Transplant Medicine, Department Of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Cees van Kooten
- Division of Nephrology and Transplant Medicine, Department Of Medicine, Leiden University Medical Center, Leiden, The Netherlands
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16
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Lammerts RGM, Eisenga MF, Alyami M, Daha MR, Seelen MA, Pol RA, van den Born J, Sanders JS, Bakker SJL, Berger SP. Urinary Properdin and sC5b-9 Are Independently Associated With Increased Risk for Graft Failure in Renal Transplant Recipients. Front Immunol 2019; 10:2511. [PMID: 31736953 PMCID: PMC6830301 DOI: 10.3389/fimmu.2019.02511] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 10/08/2019] [Indexed: 01/05/2023] Open
Abstract
The pathophysiology of late kidney-allograft failure remains complex and poorly understood. Activation of filtered or locally produced complement may contribute to the progression of renal failure through tubular C5b-9 formation. This study aimed to determine urinary properdin and sC5b-9 excretion and assess their association with long-term outcome in renal transplant recipients (RTR). Methods: We measured urinary properdin and soluble C5b-9 in a well-defined cross-sectional cohort of RTR. Urinary specimens were taken from a morning urine portion, and properdin and sC5b-9 were measured using an enzyme-linked-immunosorbent assay (ELISA). Cox proportional hazard regression analyses were used to investigate prospective associations with death-censored graft failure. Results: We included 639 stable RTR at a median [interquartile range] 5.3 (1.8-12.2) years after transplantation. Urinary properdin and sC5b-9 excretion were detectable in 161 (27%) and 102 (17%) RTR, respectively, with a median properdin level of 27.6 (8.6-68.1) ng/mL and a median sC5b-9 level of 5.1 (2.8-12.8) ng/mL. In multivariable-adjusted Cox regression analyses, including adjustment for proteinuria, urinary properdin (HR, 1.12; 95% CI 1.02-1.28; P = 0.008) and sC5b-9 excretion (HR, 1.34; 95% CI 1.10-1.63; P = 0.003) were associated with an increased risk of graft failure. If both urinary properdin and sC5b-9 were detectable, the risk of graft failure was further increased (HR, 3.12; 95% CI 1.69-5.77; P < 0.001). Conclusions: Our findings point toward a potential role for urinary complement activation in the pathogenesis of chronic allograft failure. Urinary properdin and sC5b-9 might be useful biomarkers for complement activation and chronic kidney allograft deterioration, suggesting a potential role for an alternative pathway blockade in RTR.
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Affiliation(s)
- Rosa G M Lammerts
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Michele F Eisenga
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Mohammed Alyami
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Mohamed R Daha
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Marc A Seelen
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Robert A Pol
- Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jacob van den Born
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jan-Stephan Sanders
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Stephan J L Bakker
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Stefan P Berger
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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17
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Han R, Hu S, Qin W, Shi J, Hou Q, Wang X, Xu X, Zhang M, Zeng C, Liu Z, Bao H. C3a and suPAR drive versican V1 expression in tubular cells of focal segmental glomerulosclerosis. JCI Insight 2019; 4:122912. [PMID: 30944246 DOI: 10.1172/jci.insight.122912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 02/14/2019] [Indexed: 12/13/2022] Open
Abstract
Chronic tubulointerstitial injury impacts the prognosis of focal segmental glomerulosclerosis (FSGS). We found that the level of versican V1 was increased in tubular cells of FSGS patients. Tubular cell-derived versican V1 induced proliferation and collagen synthesis by activating the CD44/Smad3 pathway in fibroblasts. Both urine C3a and suPAR were increased and bound to the tubular cells in FSGS patients. C3a promoted the transcription of versican by activating the AKT/β-catenin pathway. C3aR knockout decreased the expression of versican in Adriamycin-treated (ADR-treated) mice. On the other hand, suPAR bound to integrin β6 and activated Rac1, which bound to SRp40 at the 5' end of exon 7 in versican pre-mRNA. This binding inhibited the 3'-end splicing of intron 6 and the base-pair interactions between intron 6 and intron 8, leading to the formation of versican V1. Cotreatment with ADR and suPAR specifically increased the level of versican V1 in tubulointerstitial tissues and caused more obvious interstitial fibrosis in mice than treatment with only ADR. Altogether, our results show that C3a and suPAR drive versican V1 expression in tubular cells by promoting transcription and splicing, respectively, and the increases in tubular cell-derived versican V1 induce interstitial fibrosis by activating fibroblasts in FSGS.
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Affiliation(s)
- Runhong Han
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.,National Clinical Research Center of Kidney Diseases, Jinling Hospital, Southeast University School of Medicine, Nanjing, China
| | - Shuai Hu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Weisong Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jinsong Shi
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Qin Hou
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xia Wang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiaodong Xu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Minchao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Caihong Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.,National Clinical Research Center of Kidney Diseases, Jinling Hospital, Southeast University School of Medicine, Nanjing, China
| | - Hao Bao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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18
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Campeiro JD, Dam W, Monte GG, Porta LC, Oliveira LCGD, Nering MB, Viana GM, Carapeto FC, Oliveira EB, van den Born J, Hayashi MAF. Long term safety of targeted internalization of cell penetrating peptide crotamine into renal proximal tubular epithelial cells in vivo. Sci Rep 2019; 9:3312. [PMID: 30824773 PMCID: PMC6397221 DOI: 10.1038/s41598-019-39842-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/21/2019] [Indexed: 02/07/2023] Open
Abstract
Activated proximal tubular epithelial cells (PTECs) play a crucial role in progressive tubulo-interstitial fibrosis in native and transplanted kidneys. Targeting PTECs by non-viral delivery vectors might be useful to influence the expression of important genes and/or proteins in order to slow down renal function loss. However, no clinical therapies that specifically target PTECs are available at present. We earlier showed that a cationic cell penetrating peptide isolated from South American rattlesnake venom, named crotamine, recognizes cell surface heparan sulfate proteoglycans and accumulates in cells. In healthy mice, crotamine accumulates mainly in kidneys after intraperitoneal (ip) injection. Herein we demonstrate for the first time, the overall safety of acute or long-term treatment with daily ip administrated crotamine for kidneys functions. Accumulation of ip injected crotamine in the kidney brush border zone of PTECs, and its presence inside these cells were observed. In addition, significant lower in vitro crotamine binding, uptake and reporter gene transport and expression could be observed in syndecan-1 deficient HK-2 PTECs compared to wild-type cells, indicating that the absence of syndecan-1 impairs crotamine uptake into PTECs. Taken together, our present data show the safety of in vivo long-term treatment with crotamine, and its preferential uptake into PTECs, which are especially rich in HSPGs such as syndecan-1. In addition to the demonstrated in vitro gene delivery mediated by crotamine in HK-2 cells, the potential applicability of crotamine as prototypic non-viral (gene) delivery nanocarrier to modulate PTEC gene and/or protein expression was confirmed.
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Affiliation(s)
- Joana Darc Campeiro
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Wendy Dam
- Department Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gabriela Guilherme Monte
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Lucas Carvalho Porta
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | | | - Marcela Bego Nering
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Gustavo Monteiro Viana
- Departamento de Bioquímica, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Fernando Cintra Carapeto
- Departamento de Patologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Eduardo Brandt Oliveira
- Departamento de Bioquímica e Imunologia, Universidade de São Paulo (USP-FMRP), Ribeirão Preto, Brazil
| | - Jacob van den Born
- Department Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Mirian A F Hayashi
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil.
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19
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Han R, Hu S, Qin W, Shi J, Zeng C, Bao H, Liu Z. Upregulated long noncoding RNA LOC105375913 induces tubulointerstitial fibrosis in focal segmental glomerulosclerosis. Sci Rep 2019; 9:716. [PMID: 30679767 PMCID: PMC6345783 DOI: 10.1038/s41598-018-36902-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/24/2018] [Indexed: 01/17/2023] Open
Abstract
Tubulointerstitial fibrosis impacts renal prognosis of focal segmental glomerulosclerosis (FSGS). Based on transcriptomic analysis, we found that the level of LOC105375913 was increased in tubular cells of FSGS patients. C3a induced the expression of LOC105375913, which promoted the expression of fibronectin and collagen I in tubular cells. Silence of snail reversed the level of fibronectin and collagen I in cells overexpressing LOC105375913. MiR-27b was predicted and confirmed to regulate the expression of snail in tubular cells, and LOC105375913 contained the response element of miR-27b. The competitive binding between LOC105375913 and miR-27b increased the level of snail and promoted fibrogenesis in tubular cells. Upstream, p38 and XBP-1s regulated the expression of LOC105375913. Inhibition of p38 or silence of XBP-1s decreased the level of LOC105375913, and suppressed the expression of snail, fibronectin and collagen I in tubular cells treated with C3a. Overexpression of LOC105375913 decreased the level of miR-27b, increased the level of snail and caused tubulointerstitial fibrosis in mice. In conclusion, the activation of C3a/p38/XBP-1s pathway induces the expression of LOC105375913 in tubular cells, and LOC105375913 increases the level of snail and induces tubulointerstitial fibrosis through competitive binding of miR-27b in tubular cells of FSGS patients.
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Affiliation(s)
- Runhong Han
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China.,School of Medicine, Southeast University, Nanjing, 210009, China
| | - Shuai Hu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China
| | - Weisong Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China
| | - Jingsong Shi
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China
| | - Caihong Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China
| | - Hao Bao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China.
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, China.
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20
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Michels MAHM, Volokhina EB, van de Kar NCAJ, van den Heuvel LPWJ. The role of properdin in complement-mediated renal diseases: a new player in complement-inhibiting therapy? Pediatr Nephrol 2019; 34:1349-1367. [PMID: 30141176 PMCID: PMC6579773 DOI: 10.1007/s00467-018-4042-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 12/16/2022]
Abstract
Properdin is known as the only positive regulator of the complement system. Properdin promotes the activity of this defense system by stabilizing its key enzymatic complexes: the complement alternative pathway (AP) convertases. Besides, some studies have indicated a role for properdin as an initiator of complement activity. Though the AP is a powerful activation route of the complement system, it is also involved in a wide variety of autoimmune and inflammatory diseases, many of which affect the kidneys. The role of properdin in regulating complement in health and disease has not received as much appraisal as the many negative AP regulators, such as factor H. Historically, properdin deficiency has been strongly associated with an increased risk for meningococcal disease. Yet only recently had studies begun to link properdin to other complement-related diseases, including renal diseases. In the light of the upcoming complement-inhibiting therapies, it is interesting whether properdin can be a therapeutic target to attenuate AP-mediated injury. A full understanding of the basic concepts of properdin biology is therefore needed. Here, we first provide an overview of the function of properdin in health and disease. Then, we explore its potential as a therapeutic target for the AP-associated renal diseases C3 glomerulopathy, atypical hemolytic uremic syndrome, and proteinuria-induced tubulointerstitial injury. Considering current knowledge, properdin-inhibiting therapy seems promising in certain cases. However, knowing the complexity of properdin's role in renal pathologies in vivo, further research is required to clarify the exact potential of properdin-targeted therapy in complement-mediated renal diseases.
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Affiliation(s)
- Marloes A. H. M. Michels
- Radboud Institute for Molecular Life Sciences, Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands
| | - Elena B. Volokhina
- Radboud Institute for Molecular Life Sciences, Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands ,Department of Laboratory Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands
| | - Nicole C. A. J. van de Kar
- Radboud Institute for Molecular Life Sciences, Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands
| | - Lambertus P. W. J. van den Heuvel
- Radboud Institute for Molecular Life Sciences, Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands ,Department of Laboratory Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, PO Box 9101, 6525 GA Nijmegen, The Netherlands ,Department of Pediatrics/Pediatric Nephrology and Department of Development & Regeneration, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
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21
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O'Flynn J, Kotimaa J, Faber-Krol R, Koekkoek K, Klar-Mohamad N, Koudijs A, Schwaeble WJ, Stover C, Daha MR, van Kooten C. Properdin binds independent of complement activation in an in vivo model of anti-glomerular basement membrane disease. Kidney Int 2018; 94:1141-1150. [PMID: 30322716 DOI: 10.1016/j.kint.2018.06.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 05/31/2018] [Accepted: 06/28/2018] [Indexed: 12/31/2022]
Abstract
Properdin is the only known positive regulator of complement activation by stabilizing the alternative pathway convertase through C3 binding, thus prolonging its half-life. Recent in vitro studies suggest that properdin may act as a specific pattern recognition molecule. To better understand the role of properdin in vivo, we used an experimental model of acute anti-glomerular basement membrane disease with wild-type, C3- and properdin knockout mice. The model exhibited severe proteinuria, acute neutrophil infiltration and activation, classical and alternative pathway activation, and progressive glomerular deposition of properdin, C3 and C9. Although the acute renal injury was likely due to acute neutrophil activation, we found properdin deposition in C3-knockout mice that was not associated with IgG. Thus, properdin may deposit in injured tissues in vivo independent of its main ligand C3.
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Affiliation(s)
- Joseph O'Flynn
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Juha Kotimaa
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands; University of Helsinki, Faculty of Medicine, Department of Bacteriology and Immunology, Helsinki, Finland
| | - Ria Faber-Krol
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Karin Koekkoek
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Ngaisah Klar-Mohamad
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Angela Koudijs
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Wilhelm J Schwaeble
- University of Leicester, Department of Infection, Immunity and Inflammation, Leicester, UK
| | - Cordula Stover
- University of Leicester, Department of Infection, Immunity and Inflammation, Leicester, UK
| | - Mohamed R Daha
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Cees van Kooten
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands.
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22
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Chen JY, Cortes C, Ferreira VP. Properdin: A multifaceted molecule involved in inflammation and diseases. Mol Immunol 2018; 102:58-72. [PMID: 29954621 DOI: 10.1016/j.molimm.2018.05.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 01/17/2023]
Abstract
Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.
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Affiliation(s)
- Jin Y Chen
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
| | - Claudio Cortes
- Department of Biomedical Sciences, University of Oakland University School of Medicine, Rochester, MI, United States.
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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23
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Luo W, Olaru F, Miner JH, Beck LH, van der Vlag J, Thurman JM, Borza DB. Alternative Pathway Is Essential for Glomerular Complement Activation and Proteinuria in a Mouse Model of Membranous Nephropathy. Front Immunol 2018; 9:1433. [PMID: 29988342 PMCID: PMC6023961 DOI: 10.3389/fimmu.2018.01433] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/11/2018] [Indexed: 01/15/2023] Open
Abstract
Membranous nephropathy is an immune kidney disease caused by IgG antibodies that form glomerular subepithelial immune complexes. Proteinuria is mediated by complement activation, as a result of podocyte injury by C5b-9, but the role of specific complement pathways is not known. Autoantibodies-mediating primary membranous nephropathy are predominantly of IgG4 subclass, which cannot activate the classical pathway. Histologic evidence from kidney biopsies suggests that the lectin and the alternative pathways may be activated in membranous nephropathy, but the pathogenic relevance of these pathways remains unclear. In this study, we evaluated the role of the alternative pathway in a mouse model of membranous nephropathy. After inducing the formation of subepithelial immune complexes, we found similar glomerular IgG deposition in wild-type mice and in factor B-null mice, which lack a functional alternative pathway. Unlike wild-type mice, mice lacking factor B did not develop albuminuria nor exhibit glomerular deposition of C3c and C5b-9. Albuminuria was also reduced but not completely abolished in C5-deficient mice. Our results provide the first direct evidence that the alternative pathway is necessary for pathogenic complement activation by glomerular subepithelial immune complexes and is, therefore, a key mediator of proteinuria in experimental membranous nephropathy. This knowledge is important for the rational design of new therapies for membranous nephropathy.
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Affiliation(s)
- Wentian Luo
- Division of Nephrology, Department of Medicine, Vanderbilt Medical Center, Nashville, TN, United States.,Vanderbilt Center for Kidney Disease, Vanderbilt Division of Nephrology, Nashville, TN, United States
| | - Florina Olaru
- Division of Nephrology, Department of Medicine, Vanderbilt Medical Center, Nashville, TN, United States.,Division of Nephrology, Department of Medicine, Vanderbilt Medical Center, Nashville, TN, United States
| | - Jeffrey H Miner
- Renal Division, Washington University School of Medicine, St. Louis, MO, United States
| | - Laurence H Beck
- Division of Nephrology, Boston University Medical Center, Boston, MA, United States
| | - Johan van der Vlag
- Department of Nephrology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
| | - Dorin-Bogdan Borza
- Vanderbilt Center for Kidney Disease, Vanderbilt Division of Nephrology, Nashville, TN, United States.,Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN, United States
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24
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Membranous Nephropathy and Anti-Podocytes Antibodies: Implications for the Diagnostic Workup and Disease Management. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6281054. [PMID: 29511687 PMCID: PMC5817285 DOI: 10.1155/2018/6281054] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/31/2017] [Accepted: 10/15/2017] [Indexed: 12/11/2022]
Abstract
The discovery of circulating antibodies specific for native podocyte antigens has transformed the diagnostic workup and greatly improved management of idiopathic membranous nephropathy (iMN). In addition, their identification has clearly characterized iMN as a largely autoimmune disorder. Anti-PLA2R1 antibodies are detected in approximately 70% to 80% and anti-THSD7A antibodies in only 2% of adult patients with iMN. The presence of anti-THSD7A antibodies is associated with increased risk of malignancy. The assessment of PLA2R1 and THSD7A antigen expression in glomerular immune deposits has a better sensitivity than measurement of the corresponding autoantibodies. Therefore, in the presence of circulating anti-podocytes autoantibodies and/or enhanced expression of PLA2R1 and THSD7A antigens MN should be considered as primary MN (pMN). Anti-PLA2R1 or anti-THSD7A autoantibodies have been proposed as biomarkers of autoimmune disease activity and their blood levels should be regularly monitored in pMN to evaluate disease activity and predict outcomes. We propose a revised clinical workup flow for patients with MN that recommends assessment of kidney biopsy for PLA2R1 and THSD7A antigen expression, screening for circulating anti-podocytes antibodies, and assessment for secondary causes, especially cancer, in patients with THSD7A antibodies. Persistence of anti-podocyte antibodies for 6 months or their increase in association with nephrotic proteinuria should lead to the introduction of immunosuppressive therapies. Recent data have reported the efficacy and safety of new specific therapies targeting B cells (anti-CD20 antibodies, inhibitors of proteasome) in pMN which should lead to an update of currently outdated treatment guidelines.
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25
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Blatt AZ, Pathan S, Ferreira VP. Properdin: a tightly regulated critical inflammatory modulator. Immunol Rev 2017; 274:172-190. [PMID: 27782331 PMCID: PMC5096056 DOI: 10.1111/imr.12466] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complement alternative pathway is a powerful arm of the innate immune system that enhances diverse inflammatory responses in the human host. Key to the effects of the alternative pathway is properdin, a serum glycoprotein that can both initiate and positively regulate alternative pathway activity. Properdin is produced by many different leukocyte subsets and circulates as cyclic oligomers of monomeric subunits. While the formation of non‐physiological aggregates in purified properdin preparations and the presence of potential properdin inhibitors in serum have complicated studies of its function, properdin has, regardless, emerged as a key player in various inflammatory disease models. Here, we review basic properdin biology, emphasizing the major hurdles that have complicated the interpretation of results from properdin‐centered studies. In addition, we elaborate on an emerging role for properdin in thromboinflammation and discuss the potential utility of properdin inhibitors as long‐term therapeutic options to treat diseases marked by increased formation of platelet/granulocyte aggregates. Finally, we describe the interplay between properdin and the alternative pathway negative regulator, Factor H, and how aiming to understand these interactions can provide scientists with the most effective ways to manipulate alternative pathway activation in complex systems.
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Affiliation(s)
- Adam Z Blatt
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Sabina Pathan
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
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26
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Segarra-Medrano A, Carnicer-Caceres C, Valtierra-Carmeno N, Agraz-Pamplona I, Ramos-Terrades N, Jatem Escalante E, Ostos-Roldan E. Study of the variables associated with local complement activation in IgA nephropathy. Nefrologia 2017; 37:320-329. [PMID: 28495395 DOI: 10.1016/j.nefro.2016.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 11/13/2016] [Accepted: 11/17/2016] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVES 1. To identify the variables that are associated with urinary levels of properdin, MBL, C4d, and C5b-9 in patients with idiopathic IgA nephropathy. 2. To analyse whether urinary levels of MBL and/or C4d are useful for identifying the presence of mesangial deposits of C4d/MBL. PATIENTS AND METHOD A total of 96 patients with IgA nephropathy were studied. Demographic, clinical and biochemical variables were recorded at the time of diagnosis. Renal lesions were quantified using the Oxford classification. Immunohistochemical staining for MBL, MASP-2, properdin, C4d, and C5b-9 was performed in kidney biopsies, and in urine, the levels of properdin, MBL, C4d and C5b-9 were determined. RESULTS In multivariate analysis, the independent predictors of C4d and MBL levels in urine were the mesangial deposits of each protein and, to a lesser extent, the urinary protein excretion. The independent predictors of urinary levels of C5b-9 were MBL properdin and proteinuria. Urinary excretion of C4d had a sensitivity of 90% (95% CI: 58,7 to 99) and a specificity of 73% (95% CI: 54-87) for detecting mesangial C4d deposits, and the level of MBL had a sensitivity of 83.9% (95% CI: 62-95) and a specificity of 81.6% (95% CI: 65-92) for identifying mesangial deposits of MBL. CONCLUSION The main predictor of urinary concentration of C4d and MBL was the presence of their respective mesangial deposits. Urine MBL may contribute to complement activation in the tubular luz through the lectin pathway. Urinary levels of MBL and C4d could be sensitive and specific biomarkers for the identification of patients with mesangial deposits of MBL and C4d.
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Affiliation(s)
- Alfons Segarra-Medrano
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España.
| | - Clara Carnicer-Caceres
- Servicio de Bioquímica, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
| | - Naiara Valtierra-Carmeno
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
| | - Irene Agraz-Pamplona
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
| | - Natalia Ramos-Terrades
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
| | - Elías Jatem Escalante
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
| | - Elena Ostos-Roldan
- Servicio de Nefrología, Hospital Vall d'Hebron, Universidad Autónoma de Barcelona, Barcelona, España
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27
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Talsma DT, Daha MR, van den Born J. The bittersweet taste of tubulo-interstitial glycans. Nephrol Dial Transplant 2017; 32:611-619. [PMID: 28407128 DOI: 10.1093/ndt/gfw371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/13/2016] [Indexed: 01/06/2023] Open
Abstract
Recently, interesting work was published by Farrar et al. [1] showing the interaction of fucosylated glycoproteins on stressed tubular epithelial cells with collectin-11 leading to complement activation via the lectin route of complement. This elegant work stimulated us to evaluate the dark side (bittersweet taste) of tubulo-interstitial glycans in kidney tissue damage. As will be discussed, glycans not only initiate tubular complement activation but also orchestrate tubulo-interstitial leucocyte recruitment and growth factor responses. In this review we restrict ourselves to tubulo-interstitial damage mainly by proteinuria, ischaemia-reperfusion injury and transplantation, and we discuss the involvement of endothelial and tubular glycans in atypical and Escherichia coli-mediated haemolytic uraemic syndrome. As will be seen, fucosylated, mannosylated, galactosylated and sialylated oligosaccharide structures along with glycosaminoglycans comprise the most important glycans related to kidney injury pathways. Up to now, therapeutic interventions in these glycan-mediated injury pathways are underexplored and warrant further research.
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Affiliation(s)
- Ditmer T Talsma
- Department of Nephrology, University Medical Centre Groningen, Groningen, The Netherlands
| | - Mohamed R Daha
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands.,Department of Nephrology, Leiden University Medical Center, University of Leiden, Leiden, The Netherlands
| | - Jacob van den Born
- Department of Nephrology, University Medical Centre Groningen, Groningen, The Netherlands
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28
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Pedersen DV, Roumenina L, Jensen RK, Gadeberg TA, Marinozzi C, Picard C, Rybkine T, Thiel S, Sørensen UB, Stover C, Fremeaux-Bacchi V, Andersen GR. Functional and structural insight into properdin control of complement alternative pathway amplification. EMBO J 2017; 36:1084-1099. [PMID: 28264884 DOI: 10.15252/embj.201696173] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/16/2017] [Accepted: 01/31/2017] [Indexed: 12/22/2022] Open
Abstract
Properdin (FP) is an essential positive regulator of the complement alternative pathway (AP) providing stabilization of the C3 and C5 convertases, but its oligomeric nature challenges structural analysis. We describe here a novel FP deficiency (E244K) caused by a single point mutation which results in a very low level of AP activity. Recombinant FP E244K is monomeric, fails to support bacteriolysis, and binds weakly to C3 products. We compare this to a monomeric unit excised from oligomeric FP, which is also dysfunctional in bacteriolysis but binds the AP proconvertase, C3 convertase, C3 products and partially stabilizes the convertase. The crystal structure of such a FP-convertase complex suggests that the major contact between FP and the AP convertase is mediated by a single FP thrombospondin repeat and a small region in C3b. Small angle X-ray scattering indicates that FP E244K is trapped in a compact conformation preventing its oligomerization. Our studies demonstrate an essential role of FP oligomerization in vivo while our monomers enable detailed structural insight paving the way for novel modulators of complement.
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Affiliation(s)
- Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Lubka Roumenina
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Rasmus K Jensen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Trine Af Gadeberg
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Chiara Marinozzi
- Assistance Publique - Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
| | - Capucine Picard
- Centre d'études des déficits immunitaires, CHU Paris - Hôpital Necker-Enfants Malades, Paris, France
| | - Tania Rybkine
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Cordula Stover
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Veronique Fremeaux-Bacchi
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Sorbonne Paris Cité, Université Paris Descartes, Paris, France.,Assistance Publique - Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
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29
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Properdin binding to complement activating surfaces depends on initial C3b deposition. Proc Natl Acad Sci U S A 2017; 114:E534-E539. [PMID: 28069958 DOI: 10.1073/pnas.1612385114] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Two functions have been assigned to properdin; stabilization of the alternative convertase, C3bBb, is well accepted, whereas the role of properdin as pattern recognition molecule is controversial. The presence of nonphysiological aggregates in purified properdin preparations and experimental models that do not allow discrimination between the initial binding of properdin and binding secondary to C3b deposition is a critical factor contributing to this controversy. In previous work, by inhibiting C3, we showed that properdin binding to zymosan and Escherichia coli is not a primary event, but rather is solely dependent on initial C3 deposition. In the present study, we found that properdin in human serum bound dose-dependently to solid-phase myeloperoxidase. This binding was dependent on C3 activation, as demonstrated by the lack of binding in human serum with the C3-inhibitor compstatin Cp40, in C3-depleted human serum, or when purified properdin is applied in buffer. Similarly, binding of properdin to the surface of human umbilical vein endothelial cells or Neisseria meningitidis after incubation with human serum was completely C3-dependent, as detected by flow cytometry. Properdin, which lacks the structural homology shared by other complement pattern recognition molecules and has its major function in stabilizing the C3bBb convertase, was found to bind both exogenous and endogenous molecular patterns in a completely C3-dependent manner. We therefore challenge the view of properdin as a pattern recognition molecule, and argue that the experimental conditions used to test this hypothesis should be carefully considered, with emphasis on controlling initial C3 activation under physiological conditions.
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30
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Toward Noninvasive Diagnosis of IgA Nephropathy: A Pilot Urinary Metabolomic and Proteomic Study. DISEASE MARKERS 2016; 2016:3650909. [PMID: 27799660 PMCID: PMC5075301 DOI: 10.1155/2016/3650909] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/02/2016] [Accepted: 08/18/2016] [Indexed: 11/17/2022]
Abstract
IgA nephropathy is diagnosed by renal biopsy, an invasive procedure with a risk of significant complications. Noninvasive approaches are needed for possible diagnostic purposes and especially for monitoring disease activity or responses to treatment. In this pilot project, we assessed the utility of urine samples as source of biomarkers of IgA nephropathy. We used spot urine specimens from 19 healthy controls, 11 patients with IgA nephropathy, and 8 renal-disease controls collected on day of renal biopsy. Urine samples were analyzed using untargeted metabolomic and targeted proteomic analyses by several experimental techniques: liquid chromatography coupled with mass spectrometry, immunomagnetic isolation of target proteins coupled with quantitation by mass spectrometry, and protein arrays. No single individual biomarker completely differentiated the three groups. Therefore, we tested the utility of several markers combined in a panel. Discriminant analysis revealed that combination of seven markers, three metabolites (dodecanal, 8-hydroxyguanosine, and leukotriene C4), three proteins (α1-antitrypsin, IgA-uromodulin complex, and galactose-deficient IgA1), and heparan sulfate, differentiated patients with IgA nephropathy from patients with other renal diseases and healthy controls. Future studies are needed to validate these preliminary findings and to determine the power of these urinary markers for assessment of responses to therapy.
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31
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Borza DB. Glomerular basement membrane heparan sulfate in health and disease: A regulator of local complement activation. Matrix Biol 2016; 57-58:299-310. [PMID: 27609404 DOI: 10.1016/j.matbio.2016.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 12/26/2022]
Abstract
The glomerular basement membrane (GBM) is an essential component of the glomerular filtration barrier. Heparan sulfate proteoglycans such as agrin are major components of the GBM, along with α345(IV) collagen, laminin-521 and nidogen. A loss of GBM heparan sulfate chains is associated with proteinuria in several glomerular diseases and may contribute to the underlying pathology. As the major determinants of the anionic charge of the GBM, heparan sulfate chains have been thought to impart charge selectivity to the glomerular filtration, a view challenged by the negligible albuminuria in mice that lack heparan sulfate in the GBM. Recent studies provide increasing evidence that heparan sulfate chains modulate local complement activation by recruiting complement regulatory protein factor H, the major inhibitor of the alternative pathway in plasma. Factor H selectively inactivates C3b bound to surfaces bearing host-specific polyanions such as heparan sulfate, thus limiting complement activation on self surfaces such as the GBM, which are not protected by cell-bound complement regulators. We discuss mechanisms whereby the acquired loss of GBM heparan sulfate can impair the local regulation of the alternative pathway, exacerbating complement activation and glomerular injury in immune-mediated kidney diseases such as membranous nephropathy and lupus nephritis.
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Affiliation(s)
- Dorin-Bogdan Borza
- Department of Microbiology and Immunology, Meharry Medical College, 1005 Dr. D. B. Todd, Jr., Blvd., Nashville, TN 37208, USA.
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Mulloy B, Hogwood J, Gray E, Lever R, Page CP. Pharmacology of Heparin and Related Drugs. Pharmacol Rev 2016; 68:76-141. [PMID: 26672027 DOI: 10.1124/pr.115.011247] [Citation(s) in RCA: 227] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.
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Affiliation(s)
- Barbara Mulloy
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - John Hogwood
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Elaine Gray
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Rebecca Lever
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
| | - Clive P Page
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London, United Kingdom (B.M., C.P.P.); National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom (J.H., E.G.); and University College London School of Pharmacy, London, United Kingdom (R.L.)
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Rangan GK. C5b-9 does not mediate tubulointerstitial injury in experimental acute glomerular disease characterized by selective proteinuria. World J Nephrol 2016; 5:288-299. [PMID: 27152265 PMCID: PMC4848152 DOI: 10.5527/wjn.v5.i3.288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/14/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine whether complement membrane attack complex (C5b-9) has a pathogenic role in tubulointerstitial injury in a renal disease model characterized by acute highly selective proteinuria.
METHODS: Protein-overload nephropathy (PON) was induced in adult female Piebald-Viral-Glaxo rats with or without complement C6 deficiency (C6- and C6+) by daily intraperitoneal injections of bovine serum albumin (BSA, 2 g/d), and examined on days 2, 4 and 8.
RESULTS: Groups with PON developed equivalent levels of heavy proteinuria within 24 h of BSA injection. In C6+ rats with PON, the tubulointerstitial expression of C5b-9 was increased and localized predominantly to the basolateral surface of tubular epithelial cells (TECs), whereas it was undetectable in C6- animals. TEC proliferation (as assessed by the number of BrdU+ cells) increased by more than 50-fold in PON, peaking on day 2 and declining on days 4 to 8. There was a trend for a reduction in the number of BrdU+ TECs on day 4 in the C6- PON group (P = 0.10 compared to C6+) but not at any other time-point. Kidney enlargement, TEC apoptosis (TUNEL+ cells) and markers of tubular injury (tubule dilatation, loss of TEC height, protein cast formation) were not altered by C6 deficiency in PON. Interstitial monocyte (ED-1+ cell) accumulation was partially reduced in C6- animals with PON on day 4 (P = 0.01) but there was no change in myofibroblast accumulation.
CONCLUSION: These data suggest that C5b-9 does not mediate tubulointerstitial injury in acute glomerular diseases characterized by selective proteinuria.
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Borza DB. Alternative Pathway Dysregulation and the Conundrum of Complement Activation by IgG4 Immune Complexes in Membranous Nephropathy. Front Immunol 2016; 7:157. [PMID: 27199983 PMCID: PMC4842769 DOI: 10.3389/fimmu.2016.00157] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/11/2016] [Indexed: 11/13/2022] Open
Abstract
Membranous nephropathy (MN), a major cause of nephrotic syndrome, is a non-inflammatory immune kidney disease mediated by IgG antibodies that form glomerular subepithelial immune complexes. In primary MN, autoantibodies target proteins expressed on the podocyte surface, often phospholipase A2 receptor (PLA2R1). Pathology is driven by complement activation, leading to podocyte injury and proteinuria. This article overviews the mechanisms of complement activation and regulation in MN, addressing the paradox that anti-PLA2R1 and other antibodies causing primary MN are predominantly (but not exclusively) IgG4, an IgG subclass that does not fix complement. Besides immune complexes, alterations of the glomerular basement membrane (GBM) in MN may lead to impaired regulation of the alternative pathway (AP). The AP amplifies complement activation on surfaces insufficiently protected by complement regulatory proteins. Whereas podocytes are protected by cell-bound regulators, the GBM must recruit plasma factor H, which inhibits the AP on host surfaces carrying certain polyanions, such as heparan sulfate (HS) chains. Because HS chains present in the normal GBM are lost in MN, we posit that the local complement regulation by factor H may be impaired as a result. Thus, the loss of GBM HS in MN creates a micro-environment that promotes local amplification of complement activation, which in turn may be initiated via the classical or lectin pathways by subsets of IgG in immune complexes. A detailed understanding of the mechanisms of complement activation and dysregulation in MN is important for designing more effective therapies.
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Affiliation(s)
- Dorin-Bogdan Borza
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN, USA
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O'Flynn J, van der Pol P, Dixon KO, Prohászka Z, Daha MR, van Kooten C. Monomeric C-reactive protein inhibits renal cell-directed complement activation mediated by properdin. Am J Physiol Renal Physiol 2016; 310:F1308-16. [PMID: 26984957 DOI: 10.1152/ajprenal.00645.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/11/2016] [Indexed: 01/08/2023] Open
Abstract
Previous studies have shown that complement activation on renal tubular cells is involved in the induction of interstitial fibrosis and cellular injury. Evidence suggests that the tubular cell damage is initiated by the alternative pathway (AP) of complement with properdin having an instrumental role. Properdin is a positive regulator of the AP, which can bind necrotic cells as well as viable proximal tubular epithelial cells (PTECs), inducing complement activation. Various studies have indicated that in the circulation there is an unidentified inhibitor of properdin. We investigated the ability of C-reactive protein (CRP), both in its monomeric (mCRP) and pentameric (pCRP) form, to inhibit AP activation and injury in vitro on renal tubular cells by fluorescent microscopy, ELISA, and flow cytometry. We demonstrated that preincubation of properdin with normal human serum inhibits properdin binding to viable PTECs. We identified mCRP as a factor able to bind to properdin in solution, thereby inhibiting its binding to PTECs. In contrast, pCRP exhibited no such binding and inhibitory effect. Furthermore, mCRP was able to inhibit properdin-directed C3 and C5b-9 deposition on viable PTECs. The inhibitory ability of mCRP was not unique for viable cells but also demonstrated for binding to necrotic Jurkat cells, a target for properdin binding and complement activation. In summary, mCRP is an inhibitor of properdin in both binding to necrotic cells and viable renal cells, regulating complement activation on the cell surface. We propose that mCRP limits amplification of tissue injury by controlling properdin-directed complement activation by damaged tissue and cells.
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Affiliation(s)
- Joseph O'Flynn
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Pieter van der Pol
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Karen O Dixon
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Zoltán Prohászka
- Third Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Mohamed R Daha
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Cees van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; and
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36
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Review on complement analysis method and the roles of glycosaminoglycans in the complement system. Carbohydr Polym 2015; 134:590-7. [DOI: 10.1016/j.carbpol.2015.08.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 01/12/2023]
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Merle NS, Church SE, Fremeaux-Bacchi V, Roumenina LT. Complement System Part I - Molecular Mechanisms of Activation and Regulation. Front Immunol 2015; 6:262. [PMID: 26082779 PMCID: PMC4451739 DOI: 10.3389/fimmu.2015.00262] [Citation(s) in RCA: 1019] [Impact Index Per Article: 113.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure-function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors.
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Affiliation(s)
- Nicolas S Merle
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
| | - Sarah Elizabeth Church
- UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; UMR_S 1138, Cordeliers Research Center, Integrative Cancer Immunology Team, INSERM , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
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38
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Fearn A, Sheerin NS. Complement activation in progressive renal disease. World J Nephrol 2015; 4:31-40. [PMID: 25664245 PMCID: PMC4317626 DOI: 10.5527/wjn.v4.i1.31] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/14/2014] [Accepted: 12/10/2014] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) is common and the cause of significant morbidity and mortality. The replacement of functioning nephrons by fibrosis is characteristic of progressive disease. The pathways that lead to fibrosis are not fully understood, although chronic non-resolving inflammation in the kidney is likely to drive the fibrotic response that occurs. In patients with progressive CKD there is histological evidence of inflammation in the interstitium and strategies that reduce inflammation reduce renal injury in pre-clinical models of CKD. The complement system is an integral part of the innate immune system but also augments adaptive immune responses. Complement activation is known to occur in many diverse renal diseases, including glomerulonephritis, thrombotic microangiopathies and transplant rejection. In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease.
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39
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Langford-Smith A, Day AJ, Bishop PN, Clark SJ. Complementing the Sugar Code: Role of GAGs and Sialic Acid in Complement Regulation. Front Immunol 2015; 6:25. [PMID: 25699044 PMCID: PMC4313701 DOI: 10.3389/fimmu.2015.00025] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/12/2015] [Indexed: 01/15/2023] Open
Abstract
Sugar molecules play a vital role on both microbial and mammalian cells, where they are involved in cellular communication, govern microbial virulence, and modulate host immunity and inflammatory responses. The complement cascade, as part of a host's innate immune system, is a potent weapon against invading bacteria but has to be tightly regulated to prevent inappropriate attack and damage to host tissues. A number of complement regulators, such as factor H and properdin, interact with sugar molecules, such as glycosaminoglycans (GAGs) and sialic acid, on host and pathogen membranes and direct the appropriate complement response by either promoting the binding of complement activators or inhibitors. The binding of these complement regulators to sugar molecules can vary from location to location, due to their different specificities and because distinct structural and functional subpopulations of sugars are found in different human organs, such as the brain, kidney, and eye. This review will cover recent studies that have provided important new insights into the role of GAGs and sialic acid in complement regulation and how sugar recognition may be compromised in disease.
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Affiliation(s)
- Alex Langford-Smith
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester , Manchester , UK
| | - Paul N Bishop
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester , Manchester , UK ; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK ; Manchester Academic Health Science Centre, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK ; Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK
| | - Simon J Clark
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester , Manchester , UK ; Centre for Advanced Discovery and Experimental Therapeutics, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust , Manchester , UK
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40
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Zoja C, Abbate M, Remuzzi G. Progression of renal injury toward interstitial inflammation and glomerular sclerosis is dependent on abnormal protein filtration. Nephrol Dial Transplant 2014; 30:706-12. [PMID: 25087196 DOI: 10.1093/ndt/gfu261] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 11/14/2022] Open
Abstract
Chronic proteinuric renal diseases, independent from the type of the initial insult, have in common a loss of selectivity of the glomerular barrier to protein filtration. Glomerular sclerosis is the progressive lesion affecting the glomerular capillary wall, the primary site at which the protein filtration is abnormally enhanced by disease. Dysfunction of podocytes, that serve to maintain the intact barrier, is a central event in lesion development. However, glomerular injury is signalled to tubular and interstitial structures largely in advance of nephron destruction. Glomerular ultrafiltration of excessive amounts of plasma-derived proteins and associated factors incites tubulointerstitial damage and might amplify an inherent susceptibility of the kidney to become dysfunctional in several disease conditions. Thus, noxious substances in the proteinuric ultrafiltrate promote apoptotic responses and multiple changes in the phenotype of tubule cells with generation of inflammatory and fibrogenic mediators. The severity of tubular interstitial damage has long been recognized to be highly correlated to the degree of deterioration of renal failure even better than glomerular lesions. This review focuses on pathways of tubular injury and apoptosis that in turn promote nephron-by-nephron degeneration and interstitial fibrosis during proteinuria contributing to multifaceted processes of kidney scarring and function loss.
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Affiliation(s)
- Carlamaria Zoja
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Mauro Abbate
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Giuseppe Remuzzi
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy Unit of Nephrology and Dialysis, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy
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41
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Nagamachi S, Ohsawa I, Suzuki H, Sato N, Inoshita H, Hisada A, Honda D, Shimamoto M, Shimizu Y, Horikoshi S, Tomino Y. Properdin has an ascendancy over factor H regulation in complement-mediated renal tubular damage. BMC Nephrol 2014; 15:82. [PMID: 24885016 PMCID: PMC4037424 DOI: 10.1186/1471-2369-15-82] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 05/14/2014] [Indexed: 02/13/2023] Open
Abstract
Background Urinary (U)-complement components have been detected in patients with proteinuric renal diseases, and complement activation via the alternative pathway (AP) is believed to play a role in renal tubular damage. The present study aimed to examine the regulation of complement AP activation in patients with renal tubular damage by focusing on the balance between properdin (P) and factor H (fH). Methods In the in vivo studies, U concentrations of P, fH and membrane attack complex (MAC) were measured in patients with renal diseases using an enzyme-linked immunosorbent assay (ELISA), and their relationships with the clinical data were evaluated. In the in vitro studies, human proximal tubular epithelial cells (PTECs) were incubated with normal human serum (NHS), P-depleted serum (PDS), purified P and/or fH. Changes in cell morphology and phenotype were assessed by microscopy, real-time polymerase chain reaction (PCR), immunostaining and a cell viability assay. Results The U-P, fH and MAC concentrations were significantly higher in patients with renal disease than in normal controls and correlated with the U-protein and tubular damage markers. Furthermore, multivariate analysis revealed a relationship between P levels and tubular damage markers. There were no significant changes in morphology and mRNA expression in the AP components (P, fH, fB, C3, C5 and C9) after the addition of up to 25% NHS. Dose-dependent depositions of P or fH were observed after the addition of P or fH on PTECs. Depositions of P were not inhibited by fH in a mixture of a fixed concentration of P and a variable concentration of fH, and vice versa. Preincubation with the fixed concentration of P before the addition of NHS or PDS increased the depositions of P, C3 and MAC compared with incubation with intact NHS or intact PDS only; the depositions of C3 and MAC showed a serum-dependent trend. Preincubation with P before NHS addition significantly suppressed cell viability without causing morphological changes. Conclusions In the pathogenesis of renal tubular damage, P can directly bind to PTECs and may accelerate AP activation by surpassing fH regulation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Yasuhiko Tomino
- Division of Nephrology, Department of Internadl Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
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Olsen JG, Kragelund BB. Who climbs the tryptophan ladder? On the structure and function of the WSXWS motif in cytokine receptors and thrombospondin repeats. Cytokine Growth Factor Rev 2014; 25:337-41. [PMID: 24861947 DOI: 10.1016/j.cytogfr.2014.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 04/29/2014] [Indexed: 12/31/2022]
Abstract
For decades, a spectacular structural motif has been the focus of research in two families of animal membrane proteins: the hematopoietic cytokine type I receptors (HCR) and the thrombospondin repeat type 1 (TSR-1) domain containing proteins. Although these families include some of the best-studied and pharmaceutically most interesting human proteins, the function of the motif remains elusive. Here we show that the molecular details of the motifs are the same; that it has arisen through convergent evolution, and we argue that the same ligand binding function is maintained and suggest that the ligand can be found in the extracellular matrix (ECM). We term the motif the tryptophan ladder and suggest a function based on a comparative analysis.
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Affiliation(s)
- Johan G Olsen
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen, Denmark.
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43
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Clark SJ, Bishop PN, Day AJ. The proteoglycan glycomatrix: a sugar microenvironment essential for complement regulation. Front Immunol 2013; 4:412. [PMID: 24324472 PMCID: PMC3840399 DOI: 10.3389/fimmu.2013.00412] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023] Open
Affiliation(s)
- Simon J. Clark
- Centre for Hearing and Vision Research, Institute of Human Development, Faculty of Medicine and Human Sciences, University of Manchester, Manchester, UK
| | - Paul N. Bishop
- Centre for Hearing and Vision Research, Institute of Human Development, Faculty of Medicine and Human Sciences, University of Manchester, Manchester, UK
| | - Anthony J. Day
- Wellcome Trust Centre for Cell Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
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44
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Katta K, Boersema M, Adepu S, Rienstra H, Celie JW, Mencke R, Molema G, van Goor H, Berden JH, Navis G, Hillebrands JL, van den Born J. Renal Heparan Sulfate Proteoglycans Modulate Fibroblast Growth Factor 2 Signaling in Experimental Chronic Transplant Dysfunction. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:1571-1584. [DOI: 10.1016/j.ajpath.2013.07.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/08/2013] [Accepted: 07/31/2013] [Indexed: 12/15/2022]
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45
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The immune system and kidney disease: basic concepts and clinical implications. Nat Rev Immunol 2013; 13:738-53. [PMID: 24037418 DOI: 10.1038/nri3523] [Citation(s) in RCA: 457] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The kidneys are frequently targeted by pathogenic immune responses against renal autoantigens or by local manifestations of systemic autoimmunity. Recent studies in rodent models and humans have uncovered several underlying mechanisms that can be used to explain the previously enigmatic immunopathology of many kidney diseases. These mechanisms include kidney-specific damage-associated molecular patterns that cause sterile inflammation, the crosstalk between renal dendritic cells and T cells, the development of kidney-targeting autoantibodies and molecular mimicry with microbial pathogens. Conversely, kidney failure affects general immunity, causing intestinal barrier dysfunction, systemic inflammation and immunodeficiency that contribute to the morbidity and mortality of patients with kidney disease. In this Review, we summarize the recent findings regarding the interactions between the kidneys and the immune system.
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46
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Zaferani A, Talsma D, Richter MKS, Daha MR, Navis GJ, Seelen MA, van den Born J. Heparin/heparan sulphate interactions with complement--a possible target for reduction of renal function loss? Nephrol Dial Transplant 2013; 29:515-22. [PMID: 23880790 DOI: 10.1093/ndt/gft243] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Current management of end-stage renal failure is based on renal replacement therapy by dialysis or transplantation. Increased occurrence of renal failure in both native and transplanted kidneys indicates a need for novel therapies to stop or limit the progression of the disease. Acute kidney injury and proteinuria are major risk factors in the development of renal failure. In this regard, innate immunity plays an important role in the pathogenesis of renal diseases in both native and transplanted kidneys. The complement system is a major humoral part of innate defense. Next to the well-known complement activators, quite a number of the complement factors react with proteoglycans (PGs) both on cellular membranes and in the extracellular compartment. Therefore, these interactions might serve as targets for intervention. In this review, the current knowledge of interactions between PGs and complement is reviewed, and additionally the options for interference in the progression of renal disease are discussed.
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Affiliation(s)
- Azadeh Zaferani
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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47
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Lesher AM, Nilsson B, Song WC. Properdin in complement activation and tissue injury. Mol Immunol 2013; 56:191-8. [PMID: 23816404 DOI: 10.1016/j.molimm.2013.06.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/22/2013] [Indexed: 12/22/2022]
Abstract
The plasma protein properdin is the only known positive regulator of complement activation. Although regarded as an initiator of the alternative pathway of complement activation at the time of its discovery more than a half century ago, the role and mechanism of action of properdin in the complement cascade has undergone significant conceptual evolution since then. Despite the long history of research on properdin, however, new insight and unexpected findings on the role of properdin in complement activation, pathogen infection and host tissue injury are still being revealed by ongoing investigations. In this article, we provide a brief review on recent studies that shed new light on properdin biology, focusing on the following three topics: (1) its role as a pattern recognition molecule to direct and trigger complement activation, (2) its context-dependent requirement in complement activation on foreign and host cell surfaces, and (3) its involvement in alternative pathway complement-mediated immune disorders and considerations of properdin as a potential therapeutic target in human diseases.
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Affiliation(s)
- Allison M Lesher
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Saggu G, Cortes C, Emch HN, Ramirez G, Worth RG, Ferreira VP. Identification of a novel mode of complement activation on stimulated platelets mediated by properdin and C3(H2O). JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:6457-67. [PMID: 23677468 PMCID: PMC3784323 DOI: 10.4049/jimmunol.1300610] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Elevated numbers of activated platelets circulate in patients with chronic inflammatory diseases, including atherosclerosis and coronary disease. Activated platelets can activate the complement system. Although complement activation is essential for immune responses and removal of spent cells from circulation, it also contributes to inflammation and thrombosis, especially in patients with defective complement regulation. Proinflammatory activated leukocytes, which interact directly with platelets in response to vascular injury, are among the main sources of properdin, a positive regulator of the alternative pathway. The role of properdin in complement activation on stimulated platelets is unknown. Our data show that physiological forms of human properdin bind directly to human platelets after activation by strong agonists in the absence of C3, and bind nonproportionally to surface CD62P expression. Activation of the alternative pathway on activated platelets occurs when properdin is on the surface and recruits C3b or C3(H2O) to form C3b,Bb or a novel cell-bound C3 convertase [C3(H2O),Bb], which normally is present only in the fluid phase. Alternatively, properdin can be recruited by C3(H2O) on the platelet surface, promoting complement activation. Inhibition of factor H-mediated cell surface complement regulation significantly increases complement deposition on activated platelets with surface properdin. Finally, properdin released by activated neutrophils binds to activated platelets. Altogether, these data suggest novel molecular mechanisms for alternative pathway activation on stimulated platelets that may contribute to localization of inflammation at sites of vascular injury and thrombosis.
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Affiliation(s)
- Gurpanna Saggu
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Claudio Cortes
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
- Department of Molecular Sciences, Medical University of the Americas, Charlestown, Nevis, West Indies
| | - Heather N. Emch
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Galia Ramirez
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
- Department of Preventive Animal Medicine, Faculty of Veterinary Medicine, University of Chile, Santiago, Chile
| | - Randall G. Worth
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
| | - Viviana P. Ferreira
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH. 43614
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Novel roles of complement in renal diseases and their therapeutic consequences. Kidney Int 2013; 84:441-50. [PMID: 23615508 DOI: 10.1038/ki.2013.134] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/07/2013] [Accepted: 02/14/2013] [Indexed: 01/15/2023]
Abstract
The complement system functions as a part of the innate immune system. Inappropriate activation of the complement pathways has a deleterious effect on kidneys. Recent advances in complement research have provided new insights into the pathogenesis of glomerular and tubulointerstitial injury associated with complement activation. A new disease entity termed 'C3 glomerulopathy' has recently been proposed and is characterized by isolated C3 deposition in glomeruli without positive staining for immunoglobulins. Genetic and functional studies have demonstrated that several different mutations and disease variants, as well as the generation of autoantibodies, are potentially associated with its pathogenesis. The data from comprehensive analyses suggest that complement dysregulation can also be associated with hemolytic uremic syndrome and more common glomerular diseases, such as IgA nephropathy and diabetic kidney disease. In addition, animal studies utilizing genetically modified mice have begun to elucidate the molecular pathomechanisms associated with the complement system. From a diagnostic point of view, a noninvasive, MRI-based method for detecting C3 has recently been developed to serve as a novel tool for diagnosing complement-mediated kidney diseases. While novel therapeutic tools related to complement regulation are emerging, studies evaluating the precise roles of the complement system in kidney diseases will still be useful for developing new therapeutic approaches.
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Cortes C, Ohtola JA, Saggu G, Ferreira VP. Local release of properdin in the cellular microenvironment: role in pattern recognition and amplification of the alternative pathway of complement. Front Immunol 2013; 3:412. [PMID: 23335922 PMCID: PMC3547370 DOI: 10.3389/fimmu.2012.00412] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 12/18/2012] [Indexed: 12/24/2022] Open
Abstract
Properdin, the only positive regulatory protein of the complement system, acts as both a stabilizer of the alternative pathway (AP) convertases and as a selective pattern recognition molecule of certain microorganisms and host cells (i.e., apoptotic/necrotic cells) by serving as a platform for de novo C3b,Bb assembly. Properdin, a highly positively charged protein, normally exists as cyclic dimers (P(2)), trimers (P(3)), and tetramers (P(4)) of head-to-tail associations of monomeric 53 kDa subunits. While most complement proteins are produced mainly in the liver, properdin is synthesized primarily by various cell types, including neutrophils, monocytes, primary T cells, and shear-stressed endothelial cells resulting in properdin serum levels of 4-25 μg/ml. Multiple inflammatory agonists stimulate the release of properdin from stimulated leukocytes into the cellular microenvironment. Concentrated, focused increases in properdin levels may lead to stabilization and initiation of AP convertases, thus greatly amplifying the complement response to a local stimulus. This review highlights current knowledge related to these properties and discusses the implications of properdin production in a pro-inflammatory microenvironment.
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Affiliation(s)
- Claudio Cortes
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo Toledo, OH, USA ; Department Medical Immunology and Microbiology, Medical University of the Americas West Indies, Nevis
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