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Peterson SL, Krishnan A, Patel D, Khanehzar A, Lad A, Shaughnessy J, Ram S, Callanan D, Kunimoto D, Genead MA, Tolentino MJ. PolySialic Acid Nanoparticles Actuate Complement-Factor-H-Mediated Inhibition of the Alternative Complement Pathway: A Safer Potential Therapy for Age-Related Macular Degeneration. Pharmaceuticals (Basel) 2024; 17:517. [PMID: 38675477 PMCID: PMC11053938 DOI: 10.3390/ph17040517] [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: 03/06/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
The alternative pathway of the complement system is implicated in the etiology of age-related macular degeneration (AMD). Complement depletion with pegcetacoplan and avacincaptad pegol are FDA-approved treatments for geographic atrophy in AMD that, while effective, have clinically observed risks of choroidal neovascular (CNV) conversion, optic neuritis, and retinal vasculitis, leaving room for other equally efficacious but safer therapeutics, including Poly Sialic acid (PSA) nanoparticle (PolySia-NP)-actuated complement factor H (CFH) alternative pathway inhibition. Our previous paper demonstrated that PolySia-NP inhibits pro-inflammatory polarization and cytokine release. Here, we extend these findings by investigating the therapeutic potential of PolySia-NP to attenuate the alternative complement pathway. First, we show that PolySia-NP binds CFH and enhances affinity to C3b. Next, we demonstrate that PolySia-NP treatment of human serum suppresses alternative pathway hemolytic activity and C3b deposition. Further, we show that treating human macrophages with PolySia-NP is non-toxic and reduces markers of complement activity. Finally, we describe PolySia-NP-treatment-induced decreases in neovascularization and inflammatory response in a laser-induced CNV mouse model of neovascular AMD. In conclusion, PolySia-NP suppresses alternative pathway complement activity in human serum, human macrophage, and mouse CNV without increasing neovascularization.
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Affiliation(s)
- Sheri L. Peterson
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Anitha Krishnan
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Diyan Patel
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Ali Khanehzar
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Amit Lad
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA; (J.S.); (S.R.)
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA; (J.S.); (S.R.)
| | - David Callanan
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Derek Kunimoto
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Mohamed A. Genead
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Michael J. Tolentino
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
- Department of Ophthalmology, University of Central Florida School of Medicine, Orlando, FL 32827, USA
- Department of Ophthalmology, Orlando College of Osteopathic Medicine, Orlando, FL 34787, USA
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Scheim DE, Vottero P, Santin AD, Hirsh AG. Sialylated Glycan Bindings from SARS-CoV-2 Spike Protein to Blood and Endothelial Cells Govern the Severe Morbidities of COVID-19. Int J Mol Sci 2023; 24:17039. [PMID: 38069362 PMCID: PMC10871123 DOI: 10.3390/ijms242317039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Consistent with well-established biochemical properties of coronaviruses, sialylated glycan attachments between SARS-CoV-2 spike protein (SP) and host cells are key to the virus's pathology. SARS-CoV-2 SP attaches to and aggregates red blood cells (RBCs), as shown in many pre-clinical and clinical studies, causing pulmonary and extrapulmonary microthrombi and hypoxia in severe COVID-19 patients. SARS-CoV-2 SP attachments to the heavily sialylated surfaces of platelets (which, like RBCs, have no ACE2) and endothelial cells (having minimal ACE2) compound this vascular damage. Notably, experimentally induced RBC aggregation in vivo causes the same key morbidities as for severe COVID-19, including microvascular occlusion, blood clots, hypoxia and myocarditis. Key risk factors for COVID-19 morbidity, including older age, diabetes and obesity, are all characterized by markedly increased propensity to RBC clumping. For mammalian species, the degree of clinical susceptibility to COVID-19 correlates to RBC aggregability with p = 0.033. Notably, of the five human betacoronaviruses, the two common cold strains express an enzyme that releases glycan attachments, while the deadly SARS, SARS-CoV-2 and MERS do not, although viral loads for COVID-19 and the two common cold infections are similar. These biochemical insights also explain the previously puzzling clinical efficacy of certain generics against COVID-19 and may support the development of future therapeutic strategies for COVID-19 and long COVID patients.
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Affiliation(s)
- David E Scheim
- US Public Health Service, Commissioned Corps, Inactive Reserve, Blacksburg, VA 24060, USA
| | - Paola Vottero
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 1Z2, Canada
| | - Alessandro D Santin
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale School of Medicine, P.O. Box 208063, New Haven, CT 06520, USA
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3
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Bowen EE, Hurcombe JA, Barrington F, Keir LS, Farmer LK, Wherlock MD, Ortiz-Sandoval CG, Bruno V, Bohorquez-Hernandez A, Diatlov D, Rostam-Shirazi N, Wells S, Stewart M, Teboul L, Lay AC, Butler MJ, Pope RJP, Larkai EMS, Morgan BP, Moppett J, Satchell SC, Welsh GI, Walker PD, Licht C, Saleem MA, Coward RJM. Shiga toxin targets the podocyte causing hemolytic uremic syndrome through endothelial complement activation. MED 2023; 4:761-777.e8. [PMID: 37863058 DOI: 10.1016/j.medj.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 07/18/2023] [Accepted: 09/18/2023] [Indexed: 10/22/2023]
Abstract
BACKGROUND Shiga toxin (Stx)-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS) is the leading cause of acute kidney injury in children, with an associated mortality of up to 5%. The mechanisms underlying STEC-HUS and why the glomerular microvasculature is so susceptible to injury following systemic Stx infection are unclear. METHODS Transgenic mice were engineered to express the Stx receptor (Gb3) exclusively in their kidney podocytes (Pod-Gb3) and challenged with systemic Stx. Human glomerular cell models and kidney biopsies from patients with STEC-HUS were also studied. FINDINGS Stx-challenged Pod-Gb3 mice developed STEC-HUS. This was mediated by a reduction in podocyte vascular endothelial growth factor A (VEGF-A), which led to loss of glomerular endothelial cell (GEnC) glycocalyx, a reduction in GEnC inhibitory complement factor H binding, and local activation of the complement pathway. Early therapeutic inhibition of the terminal complement pathway with a C5 inhibitor rescued this podocyte-driven, Stx-induced HUS phenotype. CONCLUSIONS This study potentially explains why systemic Stx exposure targets the glomerulus and supports the early use of terminal complement pathway inhibition in this devastating disease. FUNDING This work was supported by the UK Medical Research Council (MRC) (grant nos. G0901987 and MR/K010492/1) and Kidney Research UK (grant nos. TF_007_20151127, RP42/2012, and SP/FSGS1/2013). The Mary Lyon Center is part of the MRC Harwell Institute and is funded by the MRC (A410).
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Affiliation(s)
- Emily E Bowen
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK; The Hospital for Sick Children, Toronto, ON MG5 1X8, Canada; University of Manchester, Manchester M13 9PT, UK.
| | - Jennifer A Hurcombe
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Fern Barrington
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Lindsay S Keir
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Louise K Farmer
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Matthew D Wherlock
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | | | | | | | - Daniel Diatlov
- The Hospital for Sick Children, Toronto, ON MG5 1X8, Canada
| | | | - Sara Wells
- MRC Harwell Institute, Mary Lyon Centre, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Michelle Stewart
- MRC Harwell Institute, Mary Lyon Centre, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Lydia Teboul
- MRC Harwell Institute, Mary Lyon Centre, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Abigail C Lay
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK; University of Manchester, Manchester M13 9PT, UK
| | - Matthew J Butler
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Robert J P Pope
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Eva M S Larkai
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - B Paul Morgan
- UK Dementia Research Institute Cardiff and Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff CF144XN. UK
| | - John Moppett
- Bristol Royal Hospital for Sick Children, Bristol BS2 8BJ, UK
| | - Simon C Satchell
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK
| | | | | | - Moin A Saleem
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK; Bristol Royal Hospital for Sick Children, Bristol BS2 8BJ, UK
| | - Richard J M Coward
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol BS1 3NY, UK; Bristol Royal Hospital for Sick Children, Bristol BS2 8BJ, UK.
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Wedekind H, Beimdiek J, Rossdam C, Kats E, Wittek V, Schumann L, Sörensen-Zender I, Fenske A, Weinhold B, Schmitt R, Tiede A, Büttner FFR, Münster-Kühnel A, Abeln M. The monosialoganglioside GM1a protects against complement attack. Cell Death Discov 2023; 9:395. [PMID: 37880236 PMCID: PMC10600102 DOI: 10.1038/s41420-023-01686-6] [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: 06/06/2023] [Revised: 09/29/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023] Open
Abstract
The complement system is a part of the innate immune system in the fluid phase and efficiently eliminates pathogens. However, its activation requires tight regulation on the host cell surface in order not to compromise cellular viability. Previously, we showed that loss of placental cell surface sialylation in mice in vivo leads to a maternal complement attack at the fetal-maternal interface, ultimately resulting in loss of pregnancy. To gain insight into the regulatory function of sialylation in complement activation, we here generated trophoblast stem cells (TSC) devoid of sialylation, which also revealed complement sensitivity and cell death in vitro. Glycolipid-analysis by multiplexed capillary gel electrophoresis coupled to laser-induced fluorescence detection (xCGE-LIF) allowed us to identify the monosialoganglioside GM1a as a key element of cell surface complement regulation. Exogenously administered GM1a integrated into the plasma membrane of trophoblasts, substantially increased binding of complement factor H (FH) and was sufficient to protect the cells from complement attack and cell death. GM1a treatment also rescued human endothelial cells and erythrocytes from complement attack in a concentration dependent manner. Furthermore, GM1a significantly reduced complement mediated hemolysis of erythrocytes from a patient with Paroxysmal nocturnal hemoglobinuria (PNH). This study demonstrates the complement regulatory potential of exogenously administered gangliosides and paves the way for sialoglycotherapeutics as a novel substance class for membrane-targeted complement regulators.
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Affiliation(s)
- Henri Wedekind
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Julia Beimdiek
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Charlotte Rossdam
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Elina Kats
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Vanessa Wittek
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Lisa Schumann
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Inga Sörensen-Zender
- Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | - Arno Fenske
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Birgit Weinhold
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Roland Schmitt
- Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany
| | - Andreas Tiede
- Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Falk F R Büttner
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Anja Münster-Kühnel
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
| | - Markus Abeln
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
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5
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Teoh CW, Riedl Khursigara M, Ortiz-Sandoval CG, Park JW, Li J, Bohorquez-Hernandez A, Bruno V, Bowen EE, Freeman SA, Robinson LA, Licht C. The loss of glycocalyx integrity impairs complement factor H binding and contributes to cyclosporine-induced endothelial cell injury. Front Med (Lausanne) 2023; 10:891513. [PMID: 36860338 PMCID: PMC9968885 DOI: 10.3389/fmed.2023.891513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 01/06/2023] [Indexed: 02/16/2023] Open
Abstract
Background Calcineurin inhibitors (CNIs) are associated with nephrotoxicity, endothelial cell dysfunction, and thrombotic microangiopathy (TMA). Evolving evidence suggests an important role for complement dysregulation in the pathogenesis of CNI-induced TMA. However, the exact mechanism(s) of CNI-induced TMA remain(s) unknown. Methods Using blood outgrowth endothelial cells (BOECs) from healthy donors, we evaluated the effects of cyclosporine on endothelial cell integrity. Specifically, we determined complement activation (C3c and C9) and regulation (CD46, CD55, CD59, and complement factor H [CFH] deposition) as these occurred on the endothelial cell surface membrane and glycocalyx. Results We found that exposing the endothelium to cyclosporine resulted in a dose- and time-dependent enhancement of complement deposition and cytotoxicity. We, therefore, employed flow cytometry, Western blotting/CFH cofactor assays, and immunofluorescence imaging to determine the expression of complement regulators and the functional activity and localization of CFH. Notably, while cyclosporine led to the upregulation of complement regulators CD46, CD55, and CD59 on the endothelial cell surface, it also diminished the endothelial cell glycocalyx through the shedding of heparan sulfate side chains. The weakened endothelial cell glycocalyx resulted in decreased CFH surface binding and surface cofactor activity. Conclusion Our findings confirm a role for complement in cyclosporine-induced endothelial injury and suggest that decreased glycocalyx density, induced by cyclosporine, is a mechanism that leads to complement alternative pathway dysregulation via decreased CFH surface binding and cofactor activity. This mechanism may apply to other secondary TMAs-in which a role for complement has so far not been recognized-and provide a potential therapeutic target and an important marker for patients on calcineurin inhibitors.
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Affiliation(s)
- Chia Wei Teoh
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada,Department of Paediatrics, University of Toronto, Toronto, ON, Canada,Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Magdalena Riedl Khursigara
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada,Department of Paediatrics, University of Toronto, Toronto, ON, Canada,Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Jee Woo Park
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jun Li
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Valentina Bruno
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada,Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada,Division of Paediatric Nephrology, Santobono-Pausilipon Children's Hospital, Naples, Italy
| | - Emily E. Bowen
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Spencer A. Freeman
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lisa A. Robinson
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada,Department of Paediatrics, University of Toronto, Toronto, ON, Canada,Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Christoph Licht
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada,Department of Paediatrics, University of Toronto, Toronto, ON, Canada,Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Science, University of Toronto, Toronto, ON, Canada,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada,*Correspondence: Christoph Licht ✉
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6
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Tolentino MJ, Tolentino AJ. Investigational drugs in clinical trials for macular degeneration. Expert Opin Investig Drugs 2022; 31:1067-1085. [PMID: 35962560 DOI: 10.1080/13543784.2022.2113375] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Intravitreal anti-vascular endothelial growth factor (VEGF) injections for exudative age-related macular degeneration (eAMD) are effective and safe but require frequent injections and have nonresponding patients. Geographic atrophy/dry AMD (gaAMD) remains an unmet medical need . New therapies are needed to address this leading cause of blindness in the increasing aged population. AREAS COVERED This paper reviews the pathogenesis of macular degeneration, current and failed therapeutics, therapies undergoing clinical trials and a rationale for why certain AMD therapies may succeed or fail . EXPERT OPINION VEGF- inhibitors reduce both vascular leakage and neovascularization. Experimental therapies that only address neovascularization or leakage will unlikely supplant anti-VEGF therapies. The most promising future therapies for eAMD, are those that target, more potently inhibit and have a more sustained effect on the VEGF pathway such as KSI-301, RGX-314, CLS-AX, EYEP-1901, OTX-TKI. GaAMD is a phenotype of phagocytic retinal cell loss. Inhibiting phagocytic activity of retinal microglial/macrophages at the border of GA and reducing complement derived activators of microglial/macrophage is the most promising strategy. Complement inhibitors (Pegcetacoplan and Avacincaptad pegol) will likely obtain FDA approval but will serve to pave the way for combined complement and direct phagocytic inhibitors such as AVD-104.
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Affiliation(s)
- Michael J Tolentino
- University of Central Florida, FL, USA.,Blue Ocean Clinical Research, Lakeland, FL, USA.,Aviceda Therapeutics, Cambridge, MA, USA
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7
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Shahraz A, Lin Y, Mbroh J, Winkler J, Liao H, Lackmann M, Bungartz A, Zipfel PF, Skerka C, Neumann H. Low molecular weight polysialic acid binds to properdin and reduces the activity of the alternative complement pathway. Sci Rep 2022; 12:5818. [PMID: 35388026 PMCID: PMC8987038 DOI: 10.1038/s41598-022-09407-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 03/21/2022] [Indexed: 11/09/2022] Open
Abstract
Sialic acids as the terminal caps of the cellular glycocalyx play an essential role in self-recognition and were shown to modulate complement processes via interaction between α2,3-linked sialic acids and complement factor H. Previously, it was suggested that low molecular weight α2,8-linked polysialic acid (polySia avDP20) interferes with complement activation, but the exact molecular mechanism is still unclear. Here, we show that soluble polySia avDP20 (molecular weight of ~ 6 kDa) reduced the binding of serum-derived alternative pathway complement activator properdin to the cell surface of lesioned Hepa-1c1c7 and PC-12 neuroblastoma cells. Furthermore, polySia avDP20 added to human serum blocked the alternative complement pathway triggered by plate-bound lipopolysaccharides. Interestingly, no inhibitory effect was observed with monosialic acid or oligosialic acid with a chain length of DP3 and DP5. In addition, polySia avDP20 directly bound properdin, but not complement factor H. These data show that soluble polySia avDP20 binds properdin and reduces the alternative complement pathway activity. Results strengthen the previously described concept of self-recognition of sialylation as check-point control of complement activation in innate immunity.
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Affiliation(s)
- Anahita Shahraz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Yuchen Lin
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Joshua Mbroh
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Jonas Winkler
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Huan Liao
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Marie Lackmann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Annemarie Bungartz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Infection Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
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8
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Xu Z, Xiang J, Luan X, Geng Z, Cao L. Novel compound heterozygous mutations in a GNE myopathy with congenital thrombocytopenia: A case report and literature review. Clin Case Rep 2022; 10:e05659. [PMID: 35414913 PMCID: PMC8978988 DOI: 10.1002/ccr3.5659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 12/28/2022] Open
Abstract
We reported a GNE myopathy with congenital thrombocytopenia on a young male patient. He presented with a 3-year history of lower distal extremity weakness initially affecting his legs. The weakness slowly progressed to lower proximal legs and upper arms last 6 months. Whole-exome sequencing revealed that the patient harbored two heterozygous gene mutations, including a novel insertion mutation c.*1037_*1038CACACACACACACACACACACA and c.C478T in exome 12 and 3 of the GNE gene (NM_001128227), respectively. The levels of serum sialic acid in this patient were considerably decreased. Muscle MRI imaging showed the anterior and medial parts of his quadriceps were heavily affected by this disease. Hematoxylin and eosin staining showed prominent rimmed vacuoles with a lack of inflammatory response in the atrophied muscle. We also undertook a review of the current literature, searching for reports in which the GNE gene mutation caused the thrombocytopenia with or without muscle weakness. This new gene mutation finding broadens the GNE disease genotype spectrum, and further investigation of the relationship between GNE gene mutations and the heterogeneity of its clinical manifestations is needed.
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Affiliation(s)
- Zhouwei Xu
- Department of NeurologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - Jingyan Xiang
- Department of NeurologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - Xinghua Luan
- Department of NeurologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - Zhi Geng
- Department of NeurologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
| | - Li Cao
- Department of NeurologyShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghaiChina
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9
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Kogan K, Haapasalo K, Kotila T, Moore R, Lappalainen P, Goldman A, Meri T. Mechanism of Borrelia immune evasion by FhbA-related proteins. PLoS Pathog 2022; 18:e1010338. [PMID: 35303742 PMCID: PMC8967061 DOI: 10.1371/journal.ppat.1010338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/30/2022] [Accepted: 02/03/2022] [Indexed: 11/18/2022] Open
Abstract
Immune evasion facilitates survival of Borrelia, leading to infections like relapsing fever and Lyme disease. Important mechanism for complement evasion is acquisition of the main host complement inhibitor, factor H (FH). By determining the 2.2 Å crystal structure of Factor H binding protein A (FhbA) from Borrelia hermsii in complex with FH domains 19–20, combined with extensive mutagenesis, we identified the structural mechanism by which B. hermsii utilizes FhbA in immune evasion. Moreover, structure-guided sequence database analysis identified a new family of FhbA-related immune evasion molecules from Lyme disease and relapsing fever Borrelia. Conserved FH-binding mechanism within the FhbA-family was verified by analysis of a novel FH-binding protein from B. duttonii. By sequence analysis, we were able to group FH-binding proteins of Borrelia into four distinct phyletic types and identified novel putative FH-binding proteins. The conserved FH-binding mechanism of the FhbA-related proteins could aid in developing new approaches to inhibit virulence and complement resistance in Borrelia. Relapsing fever and Lyme Disease are infectious diseases caused by borrelia bacteria. Relapsing fever occurs sporadically worldwide, whereas distribution of Lyme Disease is restricted to the Northern Hemisphere. Both infections are transmitted to humans by blood eating ticks or lice. These infections are often difficult to diagnose due to nonspecific symptoms. To be able to cause infection, borrelia must circumvent the human immune responses. Here we describe a mechanism, how borrelia bacteria protect themselves in the human host by utilizing host proteins. By using X-ray crystallography, we solved the structure of an outer membrane protein FhbA from a relapsing fever causing borreliae, Borrelia hermsii, in complex with human complement regulator factor H. FhbA has a unique alpha-helical fold that has not been reported earlier. The structure of the complex revealed how FhbA binds factor H in a very specific manner. Factor H bound to FhbA on the surface of borrelia protects bacteria from the complement system and lysis. Based on the structure, we performed structure-guided sequence database analysis, which suggests that similar proteins are present in all relapsing fever causing borrelia and possibly in some Lyme disease agents.
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Affiliation(s)
- Konstantin Kogan
- HiLife Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Tommi Kotila
- HiLife Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Robin Moore
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Pekka Lappalainen
- HiLife Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Adrian Goldman
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Taru Meri
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- * E-mail:
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10
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Scheim DE. A Deadly Embrace: Hemagglutination Mediated by SARS-CoV-2 Spike Protein at Its 22 N-Glycosylation Sites, Red Blood Cell Surface Sialoglycoproteins, and Antibody. Int J Mol Sci 2022; 23:2558. [PMID: 35269703 PMCID: PMC8910562 DOI: 10.3390/ijms23052558] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/11/2022] [Accepted: 02/18/2022] [Indexed: 02/06/2023] Open
Abstract
Rouleaux (stacked clumps) of red blood cells (RBCs) observed in the blood of COVID-19 patients in three studies call attention to the properties of several enveloped virus strains dating back to seminal findings of the 1940s. For COVID-19, key such properties are: (1) SARS-CoV-2 binds to RBCs in vitro and also in the blood of COVID-19 patients; (2) although ACE2 is its target for viral fusion and replication, SARS-CoV-2 initially attaches to sialic acid (SA) terminal moieties on host cell membranes via glycans on its spike protein; (3) certain enveloped viruses express hemagglutinin esterase (HE), an enzyme that releases these glycan-mediated bindings to host cells, which is expressed among betacoronaviruses in the common cold strains but not the virulent strains, SARS-CoV, SARS-CoV-2 and MERS. The arrangement and chemical composition of the glycans at the 22 N-glycosylation sites of SARS-CoV-2 spike protein and those at the sialoglycoprotein coating of RBCs allow exploration of specifics as to how virally induced RBC clumping may form. The in vitro and clinical testing of these possibilities can be sharpened by the incorporation of an existing anti-COVID-19 therapeutic that has been found in silico to competitively bind to multiple glycans on SARS-CoV-2 spike protein.
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Affiliation(s)
- David E Scheim
- US Public Health Service, Commissioned Officer, Inactive Reserve, Blacksburg, VA 24060, USA
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11
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Smolag KI, Fager Ferrari M, Zetterberg E, Leinoe E, Ek T, Blom AM, Rossing M, Martin M. Severe Congenital Thrombocytopenia Characterized by Decreased Platelet Sialylation and Moderate Complement Activation Caused by Novel Compound Heterozygous Variants in GNE. Front Immunol 2021; 12:777402. [PMID: 34858435 PMCID: PMC8630651 DOI: 10.3389/fimmu.2021.777402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/22/2021] [Indexed: 11/22/2022] Open
Abstract
Background Hereditary thrombocytopenias constitute a genetically heterogeneous cause of increased bleeding. We report a case of a 17-year-old boy suffering from severe macrothrombocytopenia throughout his life. Whole genome sequencing revealed the presence of two compound heterozygous variants in GNE encoding the enzyme UDP-N-acetyl-glucosamine-2-epimerase/N-acetylmannosamine kinase, crucial for sialic acid biosynthesis. Sialic acid is required for normal platelet life span, and biallelic variants in GNE have previously been associated with isolated macrothrombocytopenia. Furthermore, sialic acid constitutes a key ligand for complement factor H (FH), an important inhibitor of the complement system, protecting host cells from indiscriminate attack. Methods Sialic acid expression and FH binding to platelets and leukocytes was evaluated by flow cytometry. The binding of FH to erythrocytes was assessed indirectly by measuring the rate of complement mediated hemolysis. Complement activation was determined by measuring levels of C3bBbP (alternative pathway), C4d (classical/lectin pathway) and soluble terminal complement complex assays. Results The proband exhibited markedly decreased expression of sialic acid on platelets and leukocytes. Consequently, the binding of FH was strongly reduced and moderate activation of the alternative and classical/lectin complement pathways was observed, together with an increased rate of erythrocyte lysis. Conclusion We report two previously undescribed variants in GNE causing severe congenital macrothrombocytopenia in a compound heterozygous state, as a consequence of decreased platelet sialylation. The decreased sialylation of platelets, leukocytes and erythrocytes affects the binding of FH, leading to moderate complement activation and increased hemolysis.
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Affiliation(s)
- Karolina I Smolag
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Marcus Fager Ferrari
- Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Eva Zetterberg
- Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Eva Leinoe
- Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Torben Ek
- Children's Cancer Center, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Anna M Blom
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Maria Rossing
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Myriam Martin
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
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12
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Pitkänen HH, Jouppila A, Helin T, Dulipati V, Kotimaa J, Meri S, Kantele A, Jalkanen P, Julkunen I, Lassila R. COVID-19 adenovirus vaccine triggers antibodies against PF4 complexes to activate complement and platelets. Thromb Res 2021; 208:129-137. [PMID: 34768097 PMCID: PMC8571998 DOI: 10.1016/j.thromres.2021.10.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/14/2021] [Accepted: 10/28/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Vaccine-induced thrombotic thrombocytopenia (VITT) is a rare coagulation disorder reported after administration of COVID-19 adenovirus-vectored vaccines. VITT is mediated by anti-platelet factor 4 (PF4) antibodies activating platelets through the Fcγ-receptor II (FcγRII), and it is associated with strong fibrin turnover. The complement system is involved in several other immunothrombotic entities, but its impact on VITT is not established. OBJECTIVE To assess antibodies in interaction with the activation of platelets and complement triggered by VITT. METHODS Antibodies against adenovirus type 2 hexon protein, ChAdOx1 adenoviral vector-specific IgG and PF4 were analyzed by enzyme immunoassays from VITT patients (n = 5). The EDTA plasma samples of the patients and controls were used to measure both terminal complement complexes (TCC) by ELISA and aggregation of healthy donor platelets. We studied the effects of human immunoglobulin (IVIG) and glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa) on spontaneous and collagen-induced platelet aggregation supplemented with VITT plasma. RESULTS None of the patients had experienced a COVID-19 infection. Antibody analyses confirmed the immunogenicity of the adenovirus-vectored ChAdOx1 vaccine. Moreover, VITT plasma had anti-PF4 antibodies and elevated TCC levels as a sign of complement activation. In isolated healthy donor platelets, VITT patient plasma caused marked, spontaneous aggregation of platelets, which was abolished by eptifibatide and high-dose therapeutic IVIG. CONCLUSIONS Our findings suggest that VITT is triggered by antibodies against adenovirus vector and PF4-polyanion complexes which strongly co-activate complement and platelets. The spontaneous platelet aggregation was suppressed by IVIG or eptifibatide, indicating that besides FcγRII, also GPIIb/IIIa receptor exerts platelet procoagulant role in VITT.
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Affiliation(s)
- Hanna H. Pitkänen
- Helsinki University, Division of Anesthesiology, Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland,Clinical Research Institute Helsinki University Hospital, Helsinki, Finland
| | - Annukka Jouppila
- Clinical Research Institute Helsinki University Hospital, Helsinki, Finland
| | - Tuukka Helin
- HUSLAB, Clinical Chemistry, Helsinki University Hospital and University of Helsinki
| | - Vinaya Dulipati
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland
| | - Juha Kotimaa
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland,HUSLAB, Helsinki University Hospital, Finland
| | - Anu Kantele
- Meilahti Infectious Diseases and Vaccine Research Center, MeVac, Department of Infectious Diseases, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Pinja Jalkanen
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Ilkka Julkunen
- Institute of Biomedicine, University of Turku, Turku, Finland,Turku University Hospital, Clinical Microbiology, Turku, Finland
| | - Riitta Lassila
- Department of Hematology, Coagulation Disorders Unit, Helsinki University Hospital, Helsinki, Finland,Research Program in Systems Oncology, Faculty of Medicine, University of Helsinki, Finland,Finnish Institute for Health and Welfare, Helsinki, Finland,Corresponding author at: Coagulation Disorders Unit, Department of Hematology and Comprehensive Cancer Center, Laboratory Services, HUCH, PL 372, 00029 Helsinki, Finland
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13
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COVID-19 vaccines induce severe hemolysis in paroxysmal nocturnal hemoglobinuria. Blood 2021; 137:3670-3673. [PMID: 33945618 PMCID: PMC8099541 DOI: 10.1182/blood.2021011548] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/26/2021] [Indexed: 12/14/2022] Open
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14
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Lemaire M, Noone D, Lapeyraque AL, Licht C, Frémeaux-Bacchi V. Inherited Kidney Complement Diseases. Clin J Am Soc Nephrol 2021; 16:942-956. [PMID: 33536243 PMCID: PMC8216622 DOI: 10.2215/cjn.11830720] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the past 20 years, we have witnessed tremendous advances in our ability to diagnose and treat genetic diseases of the kidney caused by complement dysregulation. Staggering progress was realized toward a better understanding of the genetic underpinnings and pathophysiology of many forms of atypical hemolytic uremic syndrome (aHUS) and C3-dominant glomerulopathies that are driven by complement system abnormalities. Many of these seminal discoveries paved the way for the design and characterization of several innovative therapies, some of which have already radically improved patients' outcomes. This review offers a broad overview of the exciting developments that have occurred in the recent past, with a particular focus on single-gene (or Mendelian), complement-driven aHUS and C3-dominant glomerulopathies that should be of interest to both nephrologists and kidney researchers. The discussion is restricted to genes with robust associations with both aHUS and C3-dominant glomerulopathies (complement factor H, complement component 3, complement factor H-related proteins) or only aHUS (complement factor B, complement factor I, and membrane cofactor protein). Key questions and challenges are highlighted, along with potential avenues for future directions.
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Affiliation(s)
- Mathieu Lemaire
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada,Cell Biology Program, SickKids Research Institute, Toronto, Ontario, Canada,Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Damien Noone
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada,Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Anne-Laure Lapeyraque
- Division of Nephrology, Sainte-Justine University Hospital Center, Montreal, Quebec, Canada,Department of Pediatrics, Faculty of Medicine, University of Montréal, Québec, Canada
| | - Christoph Licht
- Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada,Cell Biology Program, SickKids Research Institute, Toronto, Ontario, Canada,Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Laboratory of Immunology, Paris, France
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15
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Åkesson A, Martin M, Blom AM, Rossing M, Gabrielaite M, Zetterberg E, Klintman J. Clinical characterization and identification of rare genetic variants in atypical hemolytic uremic syndrome: A Swedish retrospective observational study. Ther Apher Dial 2021; 25:988-1000. [PMID: 33609329 DOI: 10.1111/1744-9987.13634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/27/2021] [Accepted: 02/18/2021] [Indexed: 11/30/2022]
Abstract
Complement-mediated atypical hemolytic uremic syndrome (aHUS) is an ultra-rare renal disease primarily caused by genetic alterations in complement proteins. The genetic work-up required for confirmation of diagnosis is complicated and not always logistically accessible. The aim of the present study was to apply a diagnostic scheme compliant with the American College of Medical Genetics and Genomics guidelines to investigate the prevalence of complement-mediated aHUS among subjects formerly included in a retrospective cohort of clinically suspected aHUS. Clinical outcomes and genetic correlations to complement analyses were assessed. Subjects were investigated with medical record reviewing, inquiries, and laboratory analyses composed of whole genome sequencing; enzyme-linked immunosorbent assays for factor I, factor H, and factor H-specific antibodies; nephelometry for complement components three of four; flow cytometry for CD46 surface expression and immunoblotting for the presence of factor H-related protein 1. In total, 45% (n = 60/134) of the subjects were deceased at the time of study. Twenty of the eligible subjects consented to study participation. Based on genetic sequencing and clinical characteristics, six were categorized as definite/highly suspected complement-mediated aHUS, 10 as non-complement-mediated aHUS and four as having an HUS-like phenotype. In the complement-mediated aHUS group, two subjects had not received an aHUS diagnosis during the routine clinical management. Disease-contributing/likely disease-contributing genetic variants were identified in five subjects, including a novel missense variant in the complement factor H gene (c.3450A>G, p.I1150M). This study illustrates the risk for misdiagnosis in the management of patients with complement-mediated aHUS and the importance of a comprehensive assessment of both phenotype and genotype to reach a diagnosis.
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Affiliation(s)
- Alexander Åkesson
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
| | - Myriam Martin
- The Medical Protein Chemistry Research Group, Department of Translational Medicine, Lund University, Malmo, Sweden
| | - Anna M Blom
- The Medical Protein Chemistry Research Group, Department of Translational Medicine, Lund University, Malmo, Sweden
| | - Maria Rossing
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Migle Gabrielaite
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Eva Zetterberg
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
| | - Jenny Klintman
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
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16
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Hevey R, Pouw RB, Harris C, Ricklin D. Sweet turning bitter: Carbohydrate sensing of complement in host defence and disease. Br J Pharmacol 2020; 178:2802-2822. [PMID: 33140840 DOI: 10.1111/bph.15307] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 12/27/2022] Open
Abstract
The complement system plays a major role in threat recognition and in orchestrating responses to microbial intruders and accumulating debris. This immune surveillance is largely driven by lectins that sense carbohydrate signatures on foreign, diseased and healthy host cells and act as complement activators, regulators or receptors to shape appropriate immune responses. While carbohydrate sensing protects our bodies, misguided or impaired recognition can contribute to disease. Moreover, pathogenic microbes have evolved to evade complement by mimicking host signatures. While complement is recognized as a disease factor, we only slowly start to appreciate the role of carbohydrate interactions in the underlying processes. A better understanding of complement's sweet side will contribute to a better description of disease mechanisms and enhanced diagnostic and therapeutic options. This review introduces the key components in complement-mediated carbohydrate sensing, discusses their role in health and disease, and touches on the potential effects of carbohydrate-related disease intervention. LINKED ARTICLES: This article is part of a themed issue on Canonical and non-canonical functions of the complement system in health and disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.14/issuetoc.
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Affiliation(s)
- Rachel Hevey
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Claire Harris
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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17
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Liu W, Fu X, Liu YF, Su T, Peng J. Vorapaxar-modified polysulfone membrane with high hemocompatibility inhibits thrombosis. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111508. [PMID: 33255066 DOI: 10.1016/j.msec.2020.111508] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/30/2020] [Accepted: 09/09/2020] [Indexed: 12/19/2022]
Abstract
Hemodialysis therapy is intended for patients suffering from renal insufficiency, pancreatitis, and other serious diseases. Platelets are an important active ingredient in the thrombosis induced by hemodialysis membranes. So far, there are few studies of hemodialysis membranes focusing on the effects of protease-activated receptor 1 (PAR1) activation on the platelet membrane. Among various antithrombotic agents, vorapaxar is a novel PAR1 inhibitor with high efficacy. In this study, we constructed a vorapaxar-modified polysulfone (VMPSf) membrane using immersion-precipitation phase transformation methods and characterized the microstructure in terms of hydrophilicity and mechanical properties. The water contact angle of the VMPSf membrane was 22.45% lower than that of the PSf membrane. A focused determination of platelet morphology was obtained using scanning electron microscopy. Meanwhile, we evaluated the effects of a VMPSf membrane on platelet adhesion. We observed that the VMPSf membrane could reduce the number of adhered platelets without altering their spherical or elliptical shape. The PAR1 levels in VMPSf membranes were 7.4 MFI lower than those in PSf membranes, suggesting that this modified membrane can effectively inhibit platelet activation. Activated partial thromboplastin time (APTT, 5.3 s extension) and thrombin time (TT, 2.1 s extension) reflect good anticoagulant properties. Recalcification time (80.6 s extension) and fibrinogen adsorption (9.9 μg/cm2 reduction) were related to antithrombotic properties. To determine the biosafety of VMPSf membranes, we investigated antianaphylactic and anti-inflammatory properties in vitro and acute toxicity in vivo, it was obvious that C3a and C5a had decreased to 9.6 and 0.8 ng/mL, respectively. The results indicated that the VMPSf membrane has potential for clinical application.
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Affiliation(s)
- Wei Liu
- Department of Hematology, Xiangya Hemophilia Diagnosis and Treatment Center, Xiangya Hospital, Central South University, China
| | - Xiao Fu
- Department of Hematology, Xiangya Hemophilia Diagnosis and Treatment Center, Xiangya Hospital, Central South University, China.
| | - Yan-Feng Liu
- Department of Hematology, Xiangya Hemophilia Diagnosis and Treatment Center, Xiangya Hospital, Central South University, China
| | - Tao Su
- Department of Hematology, Xiangya Hemophilia Diagnosis and Treatment Center, Xiangya Hospital, Central South University, China
| | - Jie Peng
- Department of Hematology, Xiangya Hemophilia Diagnosis and Treatment Center, Xiangya Hospital, Central South University, China
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18
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Kaartinen K, Martola L, Aaltonen S, Meri S. Diagnostic Dilemma of Thrombotic Microangiopathy in Pregnancy. Kidney Int Rep 2020; 6:529-533. [PMID: 33615079 PMCID: PMC7879120 DOI: 10.1016/j.ekir.2020.10.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 10/27/2020] [Indexed: 01/10/2023] Open
Affiliation(s)
- Kati Kaartinen
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Leena Martola
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Sari Aaltonen
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
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19
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Direct activation of the alternative complement pathway by SARS-CoV-2 spike proteins is blocked by factor D inhibition. Blood 2020; 136:2080-2089. [PMID: 32877502 PMCID: PMC7596849 DOI: 10.1182/blood.2020008248] [Citation(s) in RCA: 249] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious respiratory virus that can lead to venous/arterial thrombosis, stroke, renal failure, myocardial infarction, thrombocytopenia, and other end-organ damage. Animal models demonstrating end-organ protection in C3-deficient mice and evidence of complement activation in humans have led to the hypothesis that SARS-CoV-2 triggers complement-mediated endothelial damage, but the mechanism is unclear. Here, we demonstrate that the SARS-CoV-2 spike protein (subunit 1 and 2), but not the N protein, directly activates the alternative pathway of complement (APC). Complement-dependent killing using the modified Ham test is blocked by either C5 or factor D inhibition. C3 fragments and C5b-9 are deposited on TF1PIGAnull target cells, and complement factor Bb is increased in the supernatant from spike protein–treated cells. C5 inhibition prevents the accumulation of C5b-9 on cells, but not C3c; however, factor D inhibition prevents both C3c and C5b-9 accumulation. Addition of factor H mitigates the complement attack. In conclusion, SARS-CoV-2 spike proteins convert nonactivator surfaces to activator surfaces by preventing the inactivation of the cell-surface APC convertase. APC activation may explain many of the clinical manifestations (microangiopathy, thrombocytopenia, renal injury, and thrombophilia) of COVID-19 that are also observed in other complement-driven diseases such as atypical hemolytic uremic syndrome and catastrophic antiphospholipid antibody syndrome. C5 inhibition prevents accumulation of C5b-9 in vitro but does not prevent upstream complement activation in response to SARS-CoV-2 spike proteins.
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20
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Yuan X, Yu J, Gerber G, Chaturvedi S, Cole M, Chen H, Metjian A, Sperati CJ, Braunstein EM, Brodsky RA. Ex vivo assays to detect complement activation in complementopathies. Clin Immunol 2020; 221:108616. [PMID: 33148511 DOI: 10.1016/j.clim.2020.108616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022]
Abstract
In complement-driven thrombotic microangiopathies, failure to regulate complement activation leads to end-organ damage. The modified Ham (mHam) test measures complement-mediated killing of a nucleated cell in vitro but lacks a confirmatory assay and reliable positive controls. We demonstrate that C5b-9 accumulation on the surface of TF1 PIGAnull cells correlates with cell killing in the mHam. We also show that Sialidase treatment of cells or addition of Shiga toxin 1 to human serum serve as a more reliable positive control for the mHam than cobra venom factor or lipopolysaccharide. Simultaneously performing the mHam and measuring C5b-9 accumulation either in GVB++ or GVB0 MgEGTA buffer with the addition of complement pathway specific inhibitors (anti-C5 antibody or a factor D inhibitor, ACH-145951) can be used to localize defects in complement regulation. As more targeted complement inhibitors become available, these assays may aid in the selection of personalized treatments for patients with complement-mediated diseases.
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Affiliation(s)
- Xuan Yuan
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jia Yu
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gloria Gerber
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Shruti Chaturvedi
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Michael Cole
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Hang Chen
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Ara Metjian
- Division of Hematology, Department of Medicine, Duke University, Durham, NC, USA
| | - C John Sperati
- Division of Nephrology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Evan M Braunstein
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Robert A Brodsky
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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21
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Dekkers G, Brouwer MC, Jeremiasse J, Kamp A, Biggs RM, van Mierlo G, Lauder S, Katti S, Kuijpers TW, Rispens T, Jongerius I. Unraveling the Effect of a Potentiating Anti-Factor H Antibody on Atypical Hemolytic Uremic Syndrome-Associated Factor H Variants. THE JOURNAL OF IMMUNOLOGY 2020; 205:1778-1786. [PMID: 32848031 DOI: 10.4049/jimmunol.2000368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
The complement system plays an important role in our innate immune system. Complement activation results in clearance of pathogens, immune complex, and apoptotic cells. The host is protected from complement-mediated damage by several complement regulators. Factor H (FH) is the most important fluid-phase regulator of the alternative pathway of the complement system. Heterozygous mutations in FH are associated with complement-related diseases such as atypical hemolytic uremic syndrome (aHUS) and age-related macular degeneration. We recently described an agonistic anti-FH mAb that can potentiate the regulatory function of FH. This Ab could serve as a potential new drug for aHUS patients and alternative to C5 blockade by eculizumab. However, it is unclear whether this Ab can potentiate FH mutant variants in addition to wild-type (WT) FH. In this study, the functionality and potential of the agonistic Ab in the context of pathogenic aHUS-related FH mutant proteins was investigated. The binding affinity of recombinant WT FH and the FH variants, W1183L, V1197A, R1210C, and G1194D to C3b was increased upon addition of the potentiating Ab and similarly, the decay-accelerating activity of all mutants is increased. The potentiating anti-FH Ab is able to restore the surface regulatory function of most of the tested FH mutants to WT FH levels on a human HAP-1 cell line and on sheep erythrocytes. In conclusion, our potentiating anti-FH is broadly active and able to enhance both WT FH function as well as most aHUS-associated FH variants tested in this study.
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Affiliation(s)
- Gillian Dekkers
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Mieke C Brouwer
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Jorn Jeremiasse
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Angela Kamp
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | | | - Gerard van Mierlo
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | | | | | - Taco W Kuijpers
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, 1105 AZ Amsterdam, the Netherlands; and.,Department of Blood Cell Research, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Ilse Jongerius
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands; .,Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, 1105 AZ Amsterdam, the Netherlands; and
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22
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Zhang L, Chen JY, Kerr C, Cobb BA, Maciejewski JP, Lin F. Reduced red blood cell surface level of Factor H as a mechanism underlying paroxysmal nocturnal hemoglobinuria. Leukemia 2020; 35:1176-1187. [PMID: 32814838 PMCID: PMC7892643 DOI: 10.1038/s41375-020-1008-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 11/09/2022]
Abstract
The absence of the cell-surface complement inhibitors CD55 and CD59 is considered the mechanism underlying the complement-mediated destruction of affected red blood cells (RBCs) in paroxysmal nocturnal hemoglobinuria (PNH) patients, but Factor H (FH), a fluid-phase complement inhibitor, has also been proposed to be involved. However, the status of FH on the PNH patient RBC surface is unclear and its precise role in PNH pathogenesis remains to be further defined. In this study, we identified significantly lower levels of surface-bound FH on the affected CD59- RBCs than on the unaffected CD59+ RBCs. Although this reduction in surface-bound FH on PNH RBCs was accompanied by decreased surface sialic acid levels, the enzymatic removal of sialic acids from these RBCs did not significantly affect the levels of surface-bound FH. We further observed higher surface levels of FH on the C3b/iC3b/C3dhigh RBCs than on C3b/iC3b/C3dlow RBCs within the affected PNH RBCs of patients treated with eculizumab. Finally, we determined that enhanced surface levels of FH on CD55/CD59-deficient RBCs from mice and PNH patients protected against complement-mediated hemolysis. Taken together, our results suggest that a reduced surface level of FH is another important mechanism underlying the pathogenesis of PNH.
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Affiliation(s)
- Lingjun Zhang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Cassandra Kerr
- Translational Hematology and Oncology Research Department, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
| | - Brian A Cobb
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Jaroslaw P Maciejewski
- Translational Hematology and Oncology Research Department, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
| | - Feng Lin
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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23
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Syed S, Viazmina L, Mager R, Meri S, Haapasalo K. Streptococci and the complement system: interplay during infection, inflammation and autoimmunity. FEBS Lett 2020; 594:2570-2585. [PMID: 32594520 DOI: 10.1002/1873-3468.13872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 11/09/2022]
Abstract
Streptococci are a broad group of Gram-positive bacteria. This genus includes various human pathogens causing significant morbidity and mortality. Two of the most important human pathogens are Streptococcus pneumoniae (pneumococcus) and Streptococcus pyogenes (group A streptococcus or GAS). Streptococcal pathogens have evolved to express virulence factors that enable them to evade complement-mediated attack. These include factor H-binding M (S. pyogenes) and pneumococcal surface protein C (PspC) (S. pneumoniae) proteins. In addition, S. pyogenes and S. pneumoniae express cytolysins (streptolysin and pneumolysin), which are able to destroy host cells. Sometimes, the interplay between streptococci, the complement, and antistreptococcal immunity may lead to an excessive inflammatory response or autoimmune disease. Understanding the fundamental role of the complement system in microbial clearance and the bacterial escape mechanisms is of paramount importance for understanding microbial virulence, in general, and, the conversion of commensals to pathogens, more specifically. Such insights may help to identify novel antibiotic and vaccine targets in bacterial pathogens to counter their growing resistance to commonly used antibiotics.
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Affiliation(s)
- Shahan Syed
- Department of Bacteriology and Immunology, University of Helsinki, Finland
| | - Larisa Viazmina
- Department of Bacteriology and Immunology, University of Helsinki, Finland
| | | | - Seppo Meri
- Department of Bacteriology and Immunology, University of Helsinki, Finland.,Humanitas University, Milano, Italy
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, University of Helsinki, Finland
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24
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Liao H, Klaus C, Neumann H. Control of Innate Immunity by Sialic Acids in the Nervous Tissue. Int J Mol Sci 2020; 21:ijms21155494. [PMID: 32752058 PMCID: PMC7432451 DOI: 10.3390/ijms21155494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Sialic acids (Sias) are the most abundant terminal sugar residues of glycoproteins and glycolipids on the surface of mammalian cells. The nervous tissue is the organ with the highest expression level of Sias. The ‘sialylation’ of glycoconjugates is performed via sialyltransferases, whereas ‘desialylation’ is done by sialidases or is a possible consequence of oxidative damage. Sialic acid residues on the neural cell surfaces inhibit complement and microglial activation, as well as phagocytosis of the underlying structures, via binding to (i) complement factor H (CFH) or (ii) sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors. In contrast, activated microglial cells show sialidase activity that desialylates both microglia and neurons, and further stimulates innate immunity via microglia and complement activation. The desialylation conveys neurons to become susceptible to phagocytosis, as well as triggers a microglial phagocytosis-associated oxidative burst and inflammation. Dysfunctions of the ‘Sia–SIGLEC’ and/or ‘Sia–complement’ axes often lead to neurological diseases. Thus, Sias on glycoconjugates of the intact glycocalyx and its desialylation are major regulators of neuroinflammation.
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Affiliation(s)
| | | | - Harald Neumann
- Correspondence: ; Tel.: +49-228-6885-500; Fax: +49-228-6885-501
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25
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Chen JY, Galwankar NS, Emch HN, Menon SS, Cortes C, Thurman JM, Merrill SA, Brodsky RA, Ferreira VP. Properdin Is a Key Player in Lysis of Red Blood Cells and Complement Activation on Endothelial Cells in Hemolytic Anemias Caused by Complement Dysregulation. Front Immunol 2020; 11:1460. [PMID: 32793201 PMCID: PMC7387411 DOI: 10.3389/fimmu.2020.01460] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 06/04/2020] [Indexed: 12/18/2022] Open
Abstract
The complement system alternative pathway (AP) can be activated excessively in inflammatory diseases, particularly when there is defective complement regulation. For instance, deficiency in complement regulators CD55 and CD59, leads to paroxysmal nocturnal hemoglobinuria (PNH), whereas Factor H mutations predispose to atypical hemolytic uremic syndrome (aHUS), both causing severe thrombohemolysis. Despite eculizumab being the treatment for these diseases, benefits vary considerably among patients. Understanding the molecular mechanisms involved in complement regulation is essential for developing new treatments. Properdin, the positive AP regulator, is essential for complement amplification by stabilizing enzymatic convertases. In this study, the role of properdin in red blood cell (RBC) lysis and endothelial cell opsonization in these AP-mediated diseases was addressed by developing in vitro assays using PNH patient RBCs and human primary endothelial cells, where the effects of inhibiting properdin, using novel monoclonal antibodies (MoAbs) that we generated and characterized, were compared to other complement inhibitors. In in vitro models of PNH, properdin inhibition prevented hemolysis of patient PNH type II and III RBCs more than inhibition of Factor B, C3, and C5 (>17-fold, or >81-fold, or >12-fold lower molar IC90 values, respectively). When tested in an in vitro aHUS hemolysis model, the anti-properdin MoAbs had 11-fold, and 86-fold lower molar IC90 values than inhibition of Factor B, or C3, respectively (P < 0.0001). When comparing target/inhibitor ratios in all hemolysis assays, inhibiting properdin was at least as efficient as the other complement inhibitors in most cases. In addition, using in vitro endothelial cell assays, the data indicate a critical novel role for properdin in promoting complement activation on human endothelial cells exposed to heme (a hemolysis by-product) and rH19-20 (to inhibit Factor H cell-surface protection), as occurs in aHUS. Inhibition of properdin or C3 in this system significantly reduced C3 fragment deposition by 75%. Altogether, the data indicate properdin is key in promoting RBC lysis and complement activation on human endothelial cells, contributing to the understanding of PNH and aHUS pathogenesis. Further studies to determine therapeutic values of inhibiting properdin in complement-mediated diseases, in particular those that are characterized by AP dysregulation, are warranted.
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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
| | - Neeti S Galwankar
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Heather N Emch
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Smrithi S Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Joshua M Thurman
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Samuel A Merrill
- Section of Hematology/Oncology, Department of Medicine, West Virginia University School of Medicine, Morgantown, WV, United States
| | - Robert A Brodsky
- Division of Hematology, Department of Medicine, John Hopkins University School of Medicine, Baltimore, MD, 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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26
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Puigdellívol M, Allendorf DH, Brown GC. Sialylation and Galectin-3 in Microglia-Mediated Neuroinflammation and Neurodegeneration. Front Cell Neurosci 2020; 14:162. [PMID: 32581723 PMCID: PMC7296093 DOI: 10.3389/fncel.2020.00162] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 05/15/2020] [Indexed: 12/31/2022] Open
Abstract
Microglia are brain macrophages that mediate neuroinflammation and contribute to and protect against neurodegeneration. The terminal sugar residue of all glycoproteins and glycolipids on the surface of mammalian cells is normally sialic acid, and addition of this negatively charged residue is known as “sialylation,” whereas removal by sialidases is known as “desialylation.” High sialylation of the neuronal cell surface inhibits microglial phagocytosis of such neurons, via: (i) activating sialic acid receptors (Siglecs) on microglia that inhibit phagocytosis and (ii) inhibiting binding of opsonins C1q, C3, and galectin-3. Microglial sialylation inhibits inflammatory activation of microglia via: (i) activating Siglec receptors CD22 and CD33 on microglia that inhibit phagocytosis and (ii) inhibiting Toll-like receptor 4 (TLR4), complement receptor 3 (CR3), and other microglial receptors. When activated, microglia release a sialidase activity that desialylates both microglia and neurons, activating the microglia and rendering the neurons susceptible to phagocytosis. Activated microglia also release galectin-3 (Gal-3), which: (i) further activates microglia via binding to TLR4 and TREM2, (ii) binds to desialylated neurons opsonizing them for phagocytosis via Mer tyrosine kinase, and (iii) promotes Aβ aggregation and toxicity in vivo. Gal-3 and desialylation may increase in a variety of brain pathologies. Thus, Gal-3 and sialidases are potential treatment targets to prevent neuroinflammation and neurodegeneration.
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Affiliation(s)
- Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - David H Allendorf
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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27
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Fujisawa M, Yasumoto A, Kato H, Sugawara Y, Yoshida Y, Yatomi Y, Nangaku M. The role of anti-complement factor H antibodies in the development of atypical haemolytic uremic syndrome: a possible contribution to abnormality of platelet function. Br J Haematol 2019; 189:182-186. [PMID: 31879952 DOI: 10.1111/bjh.16297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 10/06/2019] [Indexed: 12/01/2022]
Abstract
Atypical haemolytic uremic syndrome (aHUS) is associated with complement system abnormality, such as production of complement factor H (CFH) autoantibodies. The growing evidence indicates complement overactivation on platelets is intimately involved in aHUS pathogenesis, besides endothelial injury. We here showed plasma from patients with anti-CFH antibodies induced aggregation of washed platelets, while purified anti-CFH antibodies suppressed aggregation. This suggested anti-CFH antibody itself suppressed thrombosis, while other plasma factor including complement factors could overactivate the platelets, leading to aggregation, which augmented the notion the state of complement activation influenced by anti-CFH antibodies is important in the aggregation of platelets in aHUS.
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Affiliation(s)
- Madoka Fujisawa
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Atsushi Yasumoto
- Department of Clinical Laboratory Medicine, The University of Tokyo Hospital, Tokyo, Japan
| | - Hideki Kato
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Yuka Sugawara
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Yoko Yoshida
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory Medicine, The University of Tokyo Hospital, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
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28
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Haapasalo K, Meri S. Regulation of the Complement System by Pentraxins. Front Immunol 2019; 10:1750. [PMID: 31428091 PMCID: PMC6688104 DOI: 10.3389/fimmu.2019.01750] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/10/2019] [Indexed: 01/09/2023] Open
Abstract
The functions of pentraxins, like C-reactive protein (CRP), serum amyloid protein P (SAP) and pentraxin-3 (PTX3), are to coordinate spatially and temporally targeted clearance of injured tissue components, to protect against infections and to regulate related inflammation together with the complement system. For this, pentraxins have a dual relationship with the complement system. Initially, after a focused binding to their targets, e.g., exposed phospholipids or cholesterol in the injured tissue area, or microbial components, the pentraxins activate complement by binding its first component C1q. However, the emerging inflammation needs to be limited to the target area. Therefore, pentraxins inhibit complement at the C3b stage to prevent excessive damage. The complement inhibitory functions of pentraxins are based on their ability to interact with complement inhibitors C4bp or factor H (FH). C4bp binds to SAP, while FH binds to both CRP and PTX3. FH promotes opsonophagocytosis through inactivation of C3b to iC3b, and inhibits AP activity thus preventing formation of the C5a anaphylatoxin and the complement membrane attack complex (MAC). Monitoring CRP levels gives important clinical information about the extent of tissue damage and severity of infections. CRP is a valuable marker for distinguishing bacterial infections from viral infections. Disturbances in the functions and interactions of pentraxins and complement are also involved in a number of human diseases. This review will summarize what is currently known about the FH family proteins and pentraxins that interact with FH. Furthermore, we will discuss diseases, where interactions between these molecules may play a role.
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Affiliation(s)
- Karita Haapasalo
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Helsinki, Finland.,HUSLAB, Helsinki University Hospital, Helsinki, Finland.,Department of Biomedical Sciences, Humanitas University, Milan, Italy
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29
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Merrill SA, Brodsky RA, Lanzkron SM, Naik R. A case-control analysis of hyperhemolysis syndrome in adults and laboratory correlates of complement involvement. Transfusion 2019; 59:3129-3139. [PMID: 31292968 DOI: 10.1111/trf.15445] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/10/2019] [Accepted: 06/18/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hyperhemolysis syndrome (HS) is a poorly understood, severe hemolytic anemia provoked by transfusion. Both host and donor RBCs are destroyed in HS; thus, transfusion paradoxically worsens anemia. Risk factors and mechanism of HS are unknown. STUDY DESIGN AND METHODS A retrospective case-control analysis was performed on adults with HS. Patients with HS were matched 1:1 with matched, transfused controls, and HS risk factors were analyzed with multivariable logistic regression. HS samples were analyzed for complement deposition by flow cytometry, and an in vitro model of bystander hemolysis was developed. RESULTS Forty-one patients with 54 episodes of HS were identified in a 26-year period from 1992 to 2018. Of the HS episodes, only 18.5% were associated with a new alloantibody, and such patients were more tolerant of additional transfusion in the acute episode (p = 0.005). Thirteen percent of episodes were fatal, and HS recurred in 52.6%. Alloimmunization (odds ratio [OR], 17.3), non-B blood type (OR, 9.8), D antigen (OR, 9.1), and infection (OR, 5.5) were associated with HS on multivariable analysis. Hyperbilirubinemia was predictive of fatal HS (OR, 33.6). Increased complement was observed on RBCs during HS episodes, and the in vitro model of bystander hemolysis recapitulated complement decoration of sickled RBCs. CONCLUSIONS HS is associated with significant morbidity, mortality, and recurrence. Risk factors such as known alloimmunization, blood group, and infection predispose to HS. Bystander complement activation may drive HS. These factors may help physicians refine risk-benefit assessments for transfusion and guide further therapeutic development.
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Affiliation(s)
- Samuel A Merrill
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Robert A Brodsky
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Sophie M Lanzkron
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Rakhi Naik
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
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30
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Eriksson O, Mohlin C, Nilsson B, Ekdahl KN. The Human Platelet as an Innate Immune Cell: Interactions Between Activated Platelets and the Complement System. Front Immunol 2019; 10:1590. [PMID: 31354729 PMCID: PMC6635567 DOI: 10.3389/fimmu.2019.01590] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022] Open
Abstract
Platelets play an essential role in maintaining homeostasis in the circulatory system after an injury by forming a platelet thrombus, but they also occupy a central node in the intravascular innate immune system. This concept is supported by their extensive interactions with immune cells and the cascade systems of the blood. In this review we discuss the close relationship between platelets and the complement system and the role of these interactions during thromboinflammation. Platelets are protected from complement-mediated damage by soluble and membrane-expressed complement regulators, but they bind several complement components on their surfaces and trigger complement activation in the fluid phase. Furthermore, localized complement activation may enhance the procoagulant responses of platelets through the generation of procoagulant microparticles by insertion of sublytic amounts of C5b9 into the platelet membrane. We also highlight the role of post-translational protein modifications in regulating the complement system and the critical role of platelets in driving these reactions. In particular, modification of disulfide bonds by thiol isomerases and protein phosphorylation by extracellular kinases have emerged as important mechanisms to fine-tune complement activity in the platelet microenvironment. Lastly, we describe disorders with perturbed complement activation where part of the clinical presentation includes uncontrolled platelet activation that results in thrombocytopenia, and illustrate how complement-targeting drugs are alleviating the prothrombotic phenotype in these patients. Based on these clinical observations, we discuss the role of limited complement activation in enhancing platelet activation and consider how these drugs may provide opportunities for further dissecting the complex interactions between complement and platelets.
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Affiliation(s)
- Oskar Eriksson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Camilla Mohlin
- Linnaeus Center of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kristina N. Ekdahl
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
- Linnaeus Center of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
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31
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Syed S, Hakala P, Singh AK, Lapatto HAK, King SJ, Meri S, Jokiranta TS, Haapasalo K. Role of Pneumococcal NanA Neuraminidase Activity in Peripheral Blood. Front Cell Infect Microbiol 2019; 9:218. [PMID: 31297339 PMCID: PMC6608562 DOI: 10.3389/fcimb.2019.00218] [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] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/06/2019] [Indexed: 12/25/2022] Open
Abstract
The most frequent form of hemolytic-uremic syndrome (HUS) is associated with infections caused by Shiga-like toxin-producing Enterohaemorrhagic Escherichia coli (STEC). In rarer cases HUS can be triggered by Streptococcus pneumoniae. While production of Shiga-like toxins explains STEC-HUS, the mechanisms of pneumococcal HUS are less well-known. S. pneumoniae produces neuraminidases with activity against cell surface sialic acids that are critical for factor H-mediated complement regulation on cells and platelets. The aim of this study was to find out whether S. pneumoniae neuraminidase NanA could trigger complement activation and hemolysis in whole blood. We studied clinical S. pneumoniae isolates and two laboratory strains, a wild-type strain expressing NanA, and a NanA deletion mutant for their ability to remove sialic acids from various human cells and platelets. Red blood cell lysis and activation of complement was measured ex vivo by incubating whole blood with bacterial culture supernatants. We show here that NanA expressing S. pneumoniae strains and isolates are able to remove sialic acids from cells, and platelets. Removal of sialic acids by NanA increased complement activity in whole blood, while absence of NanA blocked complement triggering and hemolytic activity indicating that removal of sialic acids by NanA could potentially trigger pHUS.
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Affiliation(s)
- Shahan Syed
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Pipsa Hakala
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Anirudh K Singh
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Microbiology, Medical College, All India Institute of Medical Sciences, Bhopal, India
| | - Helena A K Lapatto
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Samantha J King
- Center for Microbial Pathogenesis, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, The Ohio State University, Columbus, OH, United States
| | - Seppo Meri
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - T Sakari Jokiranta
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.,SYNLAB Finland, Helsinki, Finland
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
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32
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Ueda Y, Miwa T, Ito D, Kim H, Sato S, Gullipalli D, Zhou L, Golla M, Song D, Dunaief JL, Palmer MB, Song WC. Differential contribution of C5aR and C5b-9 pathways to renal thrombic microangiopathy and macrovascular thrombosis in mice carrying an atypical hemolytic syndrome-related factor H mutation. Kidney Int 2019; 96:67-79. [PMID: 30910380 PMCID: PMC10084839 DOI: 10.1016/j.kint.2019.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 01/24/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a form of thrombotic microangiopathy (TMA) caused by dysregulated complement activation. Clinically, aHUS is effectively treated by an anti-C5 monoclonal antibody (mAb) but whether the disease is mediated by the C5a receptor (C5aR) or C5b-9 pathway, or both, is unknown. Here we address this in a factor H mutant mouse (FHR/R) which developed complement-mediated TMA as well as macrovascular thrombosis caused by an aHUS-related factor H point mutation (mouse W1206R, corresponding to human W1183R). C5 deficiency and anti-C5 mAb treatment blocked all disease manifestations in FHR/R mice. C5aR1 gene deficiency prevented macrovascular thrombosis in various organs but did not improve survival or reduce renal TMA. Conversely, C6 or C9 deficiency significantly improved survival and markedly diminished renal TMA but did not prevent macrovascular thrombosis. Interestingly, as they aged both FHR/R C6-/- and FHR/R C9-/- mice developed glomerular disease reminiscent of C3 glomerulonephritis. Thus, C5aR and C5b-9 pathways drove different aspects of disease in FHR/R mice with the C5aR pathway being responsible for macrovascular thrombosis and chronic inflammatory injury while the C5b-9 pathway caused renal TMA. Our data provide new understanding of the pathogenesis of complement-mediated TMA and macrovascular thrombosis in FHR/R mice and suggest that C5 blockade is more effective for the treatment of aHUS than selectively targeting the C5aR or C5b-9 pathway alone.
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Affiliation(s)
- Yoshiyasu Ueda
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Takashi Miwa
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daisuke Ito
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hangsoo Kim
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sayaka Sato
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Damodar Gullipalli
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lin Zhou
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Madhu Golla
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Delu Song
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joshua L Dunaief
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Matthew B Palmer
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wen-Chao Song
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Dopler A, Guntau L, Harder MJ, Palmer A, Höchsmann B, Schrezenmeier H, Simmet T, Huber-Lang M, Schmidt CQ. Self versus Nonself Discrimination by the Soluble Complement Regulators Factor H and FHL-1. THE JOURNAL OF IMMUNOLOGY 2019; 202:2082-2094. [DOI: 10.4049/jimmunol.1801545] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
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Schmidt CQ, Hipgrave Ederveen AL, Harder MJ, Wuhrer M, Stehle T, Blaum BS. Biophysical analysis of sialic acid recognition by the complement regulator Factor H. Glycobiology 2019; 28:765-773. [PMID: 29982679 PMCID: PMC6142864 DOI: 10.1093/glycob/cwy061] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 07/01/2018] [Indexed: 01/13/2023] Open
Abstract
Complement factor H (FH), an elongated and substantially glycosylated 20-domain protein, is a soluble regulator of the complement alternative pathway (AP). It contains several glycan binding sites which mediate recognition of α2-3-linked sialic acid (FH domain 20) and glycosaminoglycans (domains 6–8 and 19–20). FH also binds the complement C3-activation product C3b, a powerful opsonin and focal point for the formation of C3-convertases of the AP feedback loop. In freely circulating FH the C3b binding site in domains 19–20 is occluded, a phenomenon that is not fully understood and could be mediated by an intramolecular interaction between FH’s intrinsic sialylated glycosylation and its own sialic acid binding site. In order to assess this possibility, we characterized FH’s sialylation with respect to glycosidic linkage type and searched for further potential, not yet characterized sialic acid binding sites in FH and its seven-domain spanning splice variant and fellow complement regulator FH like-1 (FHL-1). We also probed FH binding to the sialic acid variant Neu5Gc which is not expressed in humans but on heterologous erythrocytes that restrict the human AP and in FH transgenic mice. We find that FH contains mostly α2-6-linked sialic acid, making an intramolecular interaction with its α2-3-sialic acid specific binding site and an associated self-lock mechanism unlikely, substantiate that there is only a single sialic acid binding site in FH and none in FHL-1, and demonstrate direct binding of FH to the nonhuman sialic acid Neu5Gc, supporting the use of FH transgenic mouse models for studies of complement-related diseases.
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Affiliation(s)
- Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Agnes L Hipgrave Ederveen
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef, Leiden, The Netherlands
| | - Markus J Harder
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef, Leiden, The Netherlands
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Bärbel S Blaum
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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Complement factor H family proteins in their non-canonical role as modulators of cellular functions. Semin Cell Dev Biol 2019; 85:122-131. [DOI: 10.1016/j.semcdb.2017.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/23/2017] [Accepted: 12/31/2017] [Indexed: 12/17/2022]
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36
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Abeln M, Albers I, Peters-Bernard U, Flächsig-Schulz K, Kats E, Kispert A, Tomlinson S, Gerardy-Schahn R, Münster-Kühnel A, Weinhold B. Sialic acid is a critical fetal defense against maternal complement attack. J Clin Invest 2018; 129:422-436. [PMID: 30382946 DOI: 10.1172/jci99945] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 10/30/2018] [Indexed: 02/06/2023] Open
Abstract
The negatively charged sugar sialic acid (Sia) occupies the outermost position in the bulk of cell surface glycans. Lack of sialylated glycans due to genetic ablation of the Sia-activating enzyme CMP-sialic acid synthase (CMAS) resulted in embryonic lethality around day 9.5 post coitum (E9.5) in mice. Developmental failure was caused by complement activation on trophoblasts in Cmas-/- implants and was accompanied by infiltration of maternal neutrophils at the fetal-maternal interface, intrauterine growth restriction, impaired placental development, and a thickened Reichert's membrane. This phenotype, which shared features with complement receptor 1-related protein Y (Crry) depletion, was rescued in E8.5 Cmas-/- mice upon injection of cobra venom factor, resulting in exhaustion of the maternal complement component C3. Here we show that Sia is dispensable for early development of the embryo proper but pivotal for fetal-maternal immune homeostasis during pregnancy, i.e., for protecting the allograft implant against attack by the maternal innate immune system. Finally, embryos devoid of cell surface sialylation suffered from malnutrition due to inadequate placentation as a secondary effect.
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Affiliation(s)
| | | | | | | | | | - Andreas Kispert
- Institut for Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Children's Research Institute, Medical University of South Carolina, Charleston, South Carolina, USA
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Nissilä E, Hakala P, Leskinen K, Roig A, Syed S, Van Kessel KPM, Metso J, De Haas CJC, Saavalainen P, Meri S, Chroni A, Van Strijp JAG, Öörni K, Jauhiainen M, Jokiranta TS, Haapasalo K. Complement Factor H and Apolipoprotein E Participate in Regulation of Inflammation in THP-1 Macrophages. Front Immunol 2018; 9:2701. [PMID: 30519244 PMCID: PMC6260146 DOI: 10.3389/fimmu.2018.02701] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/01/2018] [Indexed: 12/28/2022] Open
Abstract
The alternative pathway (AP) of complement is constantly active in plasma and can easily be activated on self surfaces and trigger local inflammation. Host cells are protected from AP attack by Factor H (FH), the main AP regulator in plasma. Although complement is known to play a role in atherosclerosis, the mechanisms of its contribution are not fully understood. Since FH via its domains 5-7 binds apoliporotein E (apoE) and macrophages produce apoE we examined how FH could be involved in the antiatherogenic effects of apoE. We used blood peripheral monocytes and THP-1 monocyte/macrophage cells which were also loaded with acetylated low-density lipoprotein (LDL) to form foam cells. Binding of FH and apoE on these cells was analyzed by flow cytometry. High-density lipoprotein (HDL)-mediated cholesterol efflux of activated THP-1 cells was measured and transcriptomes of THP-1 cells using mRNA sequencing were determined. We found that binding of FH to human blood monocytes and cholesterol-loaded THP-1 macrophages increased apoE binding to these cells. Preincubation of fluorescent cholesterol labeled THP-1 macrophages in the presence of FH increased cholesterol efflux and cholesterol-loaded macrophages displayed reduced transcription of proinflammatory/proatherogenic factors and increased transcription of anti-inflammatory/anti-atherogenic factors. Further incubation of THP-1 cells with serum reduced C3b/iC3b deposition. Overall, our data indicate that apoE and FH interact with monocytic cells in a concerted action and this interaction reduces complement activation and inflammation in the atherosclerotic lesions. By this way FH may participate in mediating the beneficial effects of apoE in suppressing atherosclerotic lesion progression.
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Affiliation(s)
- Eija Nissilä
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Pipsa Hakala
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Katarzyna Leskinen
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Angela Roig
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Shahan Syed
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | | | - Jari Metso
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Carla J. C. De Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Päivi Saavalainen
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Athens, Greece
| | | | | | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - T. Sakari Jokiranta
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
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38
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Yoshida Y, Kato H, Ikeda Y, Nangaku M. Pathogenesis of Atypical Hemolytic Uremic Syndrome. J Atheroscler Thromb 2018; 26:99-110. [PMID: 30393246 PMCID: PMC6365154 DOI: 10.5551/jat.rv17026] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a type of thrombotic microangiopathy (TMA) defined by thrombocytopenia, microangiopathic hemolytic anemia, and renal failure. aHUS is caused by uncontrolled complement activation in the alternative pathway (AP). A variety of genetic defects in complement-related factors or acquired autoantibodies to the complement regulators have been found in 50 to 60% of all cases. Recently, however, the classification and diagnosis of aHUS are becoming more complicated. One reason for this is that some factors, which have not been regarded as complement-related factors, have been reported as predisposing factors for phenotypic aHUS. Given that genotype is highly correlated with the phenotype of aHUS, careful analysis of underlying genetic abnormalities or acquired factors is needed to predict the prognosis or to decide an optimal treatment for the disease. Another reason is that complement dysregulation in the AP have also been found in a part of other types of TMA such as transplantation-related TMA and pregnancy-related complication. Based on these findings, it is now time to redefine aHUS according to the genetic or acquired background of abnormalities.Here, we review the pathogeneses and the corresponding phenotypes of aHUS and complement-related TMAs.
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Affiliation(s)
- Yoko Yoshida
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
| | - Hideki Kato
- Department of Prevention of Diabetes and Lifestyle-Related Diseases Graduate School of Medicine, the University of Tokyo
| | - Yoichiro Ikeda
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
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39
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Sánchez-Corral P, Pouw RB, López-Trascasa M, Józsi M. Self-Damage Caused by Dysregulation of the Complement Alternative Pathway: Relevance of the Factor H Protein Family. Front Immunol 2018; 9:1607. [PMID: 30050540 PMCID: PMC6052053 DOI: 10.3389/fimmu.2018.01607] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/28/2018] [Indexed: 12/13/2022] Open
Abstract
The alternative pathway is a continuously active surveillance arm of the complement system, and it can also enhance complement activation initiated by the classical and the lectin pathways. Various membrane-bound and plasma regulatory proteins control the activation of the potentially deleterious complement system. Among the regulators, the plasma glycoprotein factor H (FH) is the main inhibitor of the alternative pathway and its powerful amplification loop. FH belongs to a protein family that also includes FH-like protein 1 and five factor H-related (FHR-1 to FHR-5) proteins. Genetic variants and abnormal rearrangements involving the FH protein family have been linked to numerous systemic and organ-specific diseases, including age-related macular degeneration, and the renal pathologies atypical hemolytic uremic syndrome, C3 glomerulopathies, and IgA nephropathy. This review covers the known and recently emerged ligands and interactions of the human FH family proteins associated with disease and discuss the very recent experimental data that suggest FH-antagonistic and complement-activating functions for the FHR proteins.
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Affiliation(s)
- Pilar Sánchez-Corral
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain.,Department of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
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40
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Fu X, Ning JP. Synthesis and biocompatibility of an argatroban-modified polysulfone membrane that directly inhibits thrombosis. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:66. [PMID: 29744595 DOI: 10.1007/s10856-018-6054-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
Anticoagulation therapy plays a vital role in the prevention of blood clot formation during hemodialysis and hemofiltration, especially for critical care patients. Here, we synthesized a novel argatroban (Arg)-modified polysulfone (PSf) membrane for anticoagulation. Arg was grafted onto the PSF membrane via chemical modification to increase membrane hydrophilicity. Protein adsorption, coagulation, as well as activation of platelets and complement systems were greatly reduced on the Arg-modified PSf membrane. Thus, the recalcification time and the activated partial thrombin time (APTT) were increased after the modification. In comparison with the pristine PSf membrane, the Arg-modified PSf membrane showed better hemocompatibility and anticoagulation properties, indicating its potential for applications in hemodialysis and hemofiltration. Modification of the PSf membrane has been investigated in attempts to further enhance the anticoagulation properties of the hemodialysis membranes, including a heparin-modified PSf membrane. However, heparin can inhibit plasma-free thrombin, and cause the occurrence of heparin-induced thrombocytopenia (HIT), which increases the risk of bleeding during dialysis in critical care patients. To address this problem, we modified PSf membrane with as a novel direct thrombin inhibitors, argatroban (Arg). It can reversibly bind to thrombin, inhibiting not only the plasma-free thrombin in the blood, but also clot-bound thrombin.
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Affiliation(s)
- Xiao Fu
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Jian-Ping Ning
- Department of Nephropathy, Xiangya Hospital, Central South University, Changsha, 410008, China.
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41
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Koskinen AR, Cheng ZZ, Pickering MC, Kairemo K, Meri T, Cook HT, Meri S, Jokiranta TS. Distribution of exogenous complement factor H in mice in vivo. Scand J Immunol 2018; 88:e12671. [PMID: 29706017 DOI: 10.1111/sji.12671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/24/2018] [Indexed: 11/29/2022]
Abstract
Factor H is an important regulator of complement activation in plasma and on cell surfaces in both humans and mice. If FH function is compromised, inappropriate complement activation on self-surfaces can have disastrous effects as seen in the kidney diseases atypical haemolytic uremic syndrome (aHUS) and C3 glomerulopathy. As FH constructs have been proposed to be used in treatment for these diseases, we studied the distribution of exogenous FH fragments in mice. Full-length mFH, mFH1-5 and mFH18-20 fragments were radiolabelled, and their distribution was examined in WT, FH-/- and FH-/- C3-/- mice in vivo. Whole body scintigraphy revealed accumulation of radioactivity in the abdominal part of the mice, but also to the thyroid gland and urinary bladder. At organ level in WT mice, some full-length FH accumulated in internal organs, but most of it remained in the circulation. Both of the mFH fragments accumulated in the kidneys and were excreted in urine. For mFH1-5, urinary secretion is the likely cause for the accumulation. Concentration of mFH18-20 to kidneys was slower, and at tissue level, mFH18-20 was localized at the proximal tubuli in WT and FH-/- C3-/- mice. No C3-independent binding to glomeruli was detected. In conclusion, these results show that glomerular glycosaminoglycans and sialic acids alone do not collect FH in kidneys. Deposition of C3 fragments is also needed, which implies that in aHUS, the problem is in simultaneous recognition of C3 fragments and glycosaminoglycans or sialic acids by FH, not just the inability of FH to recognize glomerular endothelium as such.
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Affiliation(s)
- A R Koskinen
- Department of Bacteriology and Immunology and Research Programs Unit, Immunobiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - Z-Z Cheng
- Department of Bacteriology and Immunology and Research Programs Unit, Immunobiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - M C Pickering
- Center for Complement and Inflammation Research, Imperial College London, London, UK
| | - K Kairemo
- Department of Clinical Chemistry Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland
| | - T Meri
- Department of Bacteriology and Immunology and Research Programs Unit, Immunobiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - H T Cook
- Center for Complement and Inflammation Research, Imperial College London, London, UK
| | - S Meri
- Department of Bacteriology and Immunology and Research Programs Unit, Immunobiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - T S Jokiranta
- Department of Bacteriology and Immunology and Research Programs Unit, Immunobiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
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42
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Consequences of dysregulated complement regulators on red blood cells. Blood Rev 2018; 32:280-288. [PMID: 29397262 DOI: 10.1016/j.blre.2018.01.003] [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: 06/14/2017] [Revised: 12/07/2017] [Accepted: 01/25/2018] [Indexed: 02/07/2023]
Abstract
The complement system represents the first line of defense that is involved in the clearance of pathogens, dying cells and immune complexes via opsonization, induction of an inflammatory response and the formation of a lytic pore. Red blood cells (RBCs) are very important for the delivery of oxygen to tissues and are continuously in contact with complement proteins in the blood plasma. To prevent complement activation on RBCs, various complement regulatory proteins can be found in plasma and on the cell membrane. RBCs are special cells without a nucleus and having a slightly different make-up of complement regulators than nucleated cells, as membrane cofactor protein (MCP) is not expressed and complement receptor 1 (CR1) is highly expressed. Decreased expression and/or function of complement regulatory proteins may result in unwanted complement activation and accelerated removal of RBCs. This review describes complement regulation on RBCs and the consequences when this regulation is out of balance.
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43
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Antonioli AH, White J, Crawford F, Renner B, Marchbank KJ, Hannan JP, Thurman JM, Marrack P, Holers VM. Modulation of the Alternative Pathway of Complement by Murine Factor H-Related Proteins. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:316-326. [PMID: 29187587 PMCID: PMC5736413 DOI: 10.4049/jimmunol.1602017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 10/27/2017] [Indexed: 01/21/2023]
Abstract
Factor H (FH) is a key alternative pathway regulator that controls complement activation both in the fluid phase and on specific cell surfaces, thus allowing the innate immune response to discriminate between self and foreign pathogens. However, the interrelationships between FH and a group of closely related molecules, designated the FH-related (FHR) proteins, are currently not well understood. Whereas some studies have suggested that human FHR proteins possess complement regulatory abilities, recent studies have shown that FHR proteins are potent deregulators. Furthermore, the roles of the FHR proteins have not been explored in any in vivo models of inflammatory disease. In this study, we report the cloning and expression of recombinant mouse FH and three FHR proteins (FHR proteins A-C). Results from functional assays show that FHR-A and FHR-B proteins antagonize the protective function of FH in sheep erythrocyte hemolytic assays and increase cell-surface C3b deposition on a mouse kidney proximal tubular cell line (TEC) and a human retinal pigment epithelial cell line (ARPE-19). We also report apparent KD values for the binding interaction of mouse C3d with mouse FH (3.85 μM), FHR-A (136 nM), FHR-B (546 nM), and FHR-C (1.04 μM), which directly correlate with results from functional assays. Collectively, our work suggests that similar to their human counterparts, a subset of mouse FHR proteins have an important modulatory role in complement activation. Further work is warranted to define the in vivo context-dependent roles of these proteins and determine whether FHR proteins are suitable therapeutic targets for the treatment of complement-driven diseases.
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Affiliation(s)
| | - Janice White
- Howard Hughes Medical Institute, Denver, CO 80206
| | | | - Brandon Renner
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Kevin J Marchbank
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Jonathan P Hannan
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045
| | - Philippa Marrack
- Howard Hughes Medical Institute, Denver, CO 80206
- Department of Biomedical Research, National Jewish Health, Denver, CO 80206; and
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045
| | - V Michael Holers
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045;
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44
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Crystal structure of a tripartite complex between C3dg, C-terminal domains of factor H and OspE of Borrelia burgdorferi. PLoS One 2017; 12:e0188127. [PMID: 29190743 PMCID: PMC5708776 DOI: 10.1371/journal.pone.0188127] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/01/2017] [Indexed: 11/19/2022] Open
Abstract
Complement is an important part of innate immunity. The alternative pathway of complement is activated when the main opsonin, C3b coats non-protected surfaces leading to opsonisation, phagocytosis and cell lysis. The alternative pathway is tightly controlled to prevent autoactivation towards host cells. The main regulator of the alternative pathway is factor H (FH), a soluble glycoprotein that terminates complement activation in multiple ways. FH recognizes host cell surfaces via domains 19-20 (FH19-20). All microbes including Borrelia burgdorferi, the causative agent of Lyme borreliosis, must evade complement activation to allow the infectious agent to survive in its host. One major mechanism that Borrelia uses is to recruit FH from host. Several outer surface proteins (Osp) have been described to bind FH via the C-terminus, and OspE is one of them. Here we report the structure of the tripartite complex formed by OspE, FH19-20 and C3dg at 3.18 Å, showing that OspE and C3dg can bind simultaneously to FH19-20. This verifies that FH19-20 interacts via the "common microbial binding site" on domain 20 with OspE and simultaneously and independently via domain 19 with C3dg. The spatial organization of the tripartite complex explains how OspE on the bacterial surface binds FH19-20, leaving FH fully available to protect the bacteria against complement. Additionally, formation of tripartite complex between FH, microbial protein and C3dg might enable enhanced protection, particularly on those regions on the bacteria where previous complement activation led to deposition of C3d. This might be especially important for slow-growing bacteria that cause chronic disease like Borrelia burgdorferi.
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45
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Blatt AZ, Saggu G, Cortes C, Herbert AP, Kavanagh D, Ricklin D, Lambris JD, Ferreira VP. Factor H C-Terminal Domains Are Critical for Regulation of Platelet/Granulocyte Aggregate Formation. Front Immunol 2017; 8:1586. [PMID: 29218045 PMCID: PMC5703703 DOI: 10.3389/fimmu.2017.01586] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/03/2017] [Indexed: 11/16/2022] Open
Abstract
Platelet/granulocyte aggregates (PGAs) increase thromboinflammation in the vasculature, and PGA formation is tightly controlled by the complement alternative pathway (AP) negative regulator, Factor H (FH). Mutations in FH are associated with the prothrombotic disease atypical hemolytic uremic syndrome (aHUS), yet it is unknown whether increased PGA formation contributes to the thrombosis seen in patients with aHUS. Here, flow cytometry assays were used to evaluate the effects of aHUS-related mutations on FH regulation of PGA formation and characterize the mechanism. Utilizing recombinant fragments of FH spanning the entire length of the protein, we mapped the regions of FH most critical for limiting AP activity on the surface of isolated human platelets and neutrophils, as well as the regions most critical for regulating PGA formation in human whole blood stimulated with thrombin receptor-activating peptide (TRAP). FH domains 19–20 were the most critical for limiting AP activity on platelets, neutrophils, and at the platelet/granulocyte interface. The role of FH in PGA formation was attributed to its ability to regulate AP-mediated C5a generation. AHUS-related mutations in domains 19–20 caused differential effects on control of PGA formation and AP activity on platelets and neutrophils. Our data indicate FH C-terminal domains are key for regulating PGA formation, thus increased FH protection may have a beneficial impact on diseases characterized by increased PGA formation, such as cardiovascular disease. Additionally, aHUS-related mutations in domains 19–20 have varying effects on control of TRAP-mediated PGA formation, suggesting that some, but not all, aHUS-related mutations may cause increased PGA formation that contributes to excessive thrombosis in patients with aHUS.
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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, United States
| | - Gurpanna Saggu
- 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, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Andrew P Herbert
- The School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - David Kavanagh
- The National Renal Complement Therapeutics Centre, Newcastle upon Tyne, United Kingdom.,Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 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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46
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Bowen EE, Coward RJ. Advances in our understanding of the pathogenesis of hemolytic uremic syndromes. Am J Physiol Renal Physiol 2017; 314:F454-F461. [PMID: 29167171 DOI: 10.1152/ajprenal.00376.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hemolytic uremic syndrome (HUS) is major global health care issue as it is the leading cause of acute kidney injury in children. It is a triad of acute kidney injury, microangiopathic hemolytic anemia, and thrombocytopenia. In recent years, major advances in our understanding of complement-driven inherited rare forms of HUS have been achieved. However, in children 90% of cases of HUS are associated with a Shiga toxin-producing enteric pathogen. The precise pathological mechanisms in this setting are yet to be elucidated. The purpose of this review is to discuss advances in our understanding of the pathophysiology underlying HUS and identify the key questions yet to be answered by the scientific community.
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Affiliation(s)
- E E Bowen
- Academic Renal Unit, School of Clinical Sciences, University of Bristol , Bristol , United Kingdom
| | - R J Coward
- Academic Renal Unit, School of Clinical Sciences, University of Bristol , Bristol , United Kingdom
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47
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van Beek AE, Pouw RB, Brouwer MC, van Mierlo G, Geissler J, Ooijevaar-de Heer P, de Boer M, van Leeuwen K, Rispens T, Wouters D, Kuijpers TW. Factor H-Related (FHR)-1 and FHR-2 Form Homo- and Heterodimers, while FHR-5 Circulates Only As Homodimer in Human Plasma. Front Immunol 2017; 8:1328. [PMID: 29093712 PMCID: PMC5651247 DOI: 10.3389/fimmu.2017.01328] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 09/29/2017] [Indexed: 01/11/2023] Open
Abstract
The complement factor H-related (FHR) proteins are hypothesized to fine-tune the regulatory role of complement factor H (FH) in the alternative pathway of the complement system. Moreover, FHR-1, FHR-2, and FHR-5 have been proposed to be dimers, which further complicates accurate analysis. As FHRs are highly similar among themselves and toward FH, obtaining specific reagents for quantification of serum levels and functional analysis is challenging. In this study, we generated antibodies and developed ELISAs to measure FHR-1, FHR-2, and FHR-5 in serum. We used both recombinant and serum-derived proteins to show that four dimers occur in human circulation: homodimers of FHR-1, FHR-2, and FHR-5, as well as FHR-1/FHR-2 heterodimers. Heterodimers containing FHR-5 were not found. In individuals with homozygous CFHR1 deletions or compound heterozygous CFHR2 missense/nonsense mutations identified in this study, the respective FHR-1 and FHR-2 homo- and heterodimers were absent. Using FRET, we found that recombinant FHR dimers exchange monomers rapidly. This was confirmed ex vivo, using FHR-1- and FHR-2-deficient sera. Of all FHR dimers, FHR-5/5 homodimers demonstrated strong binding affinity toward heparin. Specific ELISAs demonstrated that serum levels of FHR-1/1, FHR-1/2, FHR-2/2, and FHR-5/5 dimers were low compared to FH, which circulates at a 10- to 200-fold molar excess. In summary, FHR-1, FHR-2, and FHR-5 homodimerize, with FHR-1 and FHR-2 forming heterodimers as well, and equilibrate quickly in plasma.
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Affiliation(s)
- Anna E van Beek
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Centre, Amsterdam, Netherlands
| | - Richard B Pouw
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Centre, Amsterdam, Netherlands
| | - Mieke C Brouwer
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Gerard van Mierlo
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Judy Geissler
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Pleuni Ooijevaar-de Heer
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Martin de Boer
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Karin van Leeuwen
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Diana Wouters
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Taco W Kuijpers
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory of the Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Centre, Amsterdam, Netherlands
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48
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Abstract
Adjunctive therapies have been proposed for use in at least 5 inflammation pathobiology phenotypes in pediatric sepsis-induced multiple organ failure. This article discusses host-pathogen interaction prototypes to facilitate understanding of the rationale for personalized therapy in these phenotypes. The article discusses the literature on adjunctive antiinflammatory and immune modulation therapies that, in addition to traditional organ support and infection source control, might be part of a personalized precision medicine approach to the reversal of each of these inflammatory pathobiology phenotypes.
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49
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Cserhalmi M, Csincsi ÁI, Mezei Z, Kopp A, Hebecker M, Uzonyi B, Józsi M. The Murine Factor H-Related Protein FHR-B Promotes Complement Activation. Front Immunol 2017; 8:1145. [PMID: 28974948 PMCID: PMC5610720 DOI: 10.3389/fimmu.2017.01145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/30/2017] [Indexed: 12/03/2022] Open
Abstract
Factor H-related (FHR) proteins consist of varying number of complement control protein domains that display various degrees of sequence identity to respective domains of the alternative pathway complement inhibitor factor H (FH). While such FHR proteins are described in several species, only human FHRs were functionally investigated. Their biological role is still poorly understood and in part controversial. Recent studies on some of the human FHRs strongly suggest a role for FHRs in enhancing complement activation via competing with FH for binding to certain ligands and surfaces. The aim of the current study was the functional characterization of a murine FHR, FHR-B. To this end, FHR-B was expressed in recombinant form. Recombinant FHR-B bound to human C3b and was able to compete with human FH for C3b binding. FHR-B supported the assembly of functionally active C3bBb alternative pathway C3 convertase via its interaction with C3b. This activity was confirmed by demonstrating C3 activation in murine serum. In addition, FHR-B bound to murine pentraxin 3 (PTX3), and this interaction resulted in murine C3 fragment deposition due to enhanced complement activation in mouse serum. FHR-B also induced C3 deposition on C-reactive protein, the extracellular matrix (ECM) extract Matrigel, and endothelial cell-derived ECM when exposed to mouse serum. Moreover, mouse C3 deposition was strongly enhanced on necrotic Jurkat T cells and the mouse B cell line A20 by FHR-B. FHR-B also induced lysis of sheep erythrocytes when incubated in mouse serum with FHR-B added in excess. Altogether, these data demonstrate that, similar to human FHR-1 and FHR-5, mouse FHR-B modulates complement activity by promoting complement activation via interaction with C3b and via competition with murine FH.
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Affiliation(s)
- Marcell Cserhalmi
- MTA-ELTE Lendület Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Ádám I Csincsi
- MTA-ELTE Lendület Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Zoltán Mezei
- MTA-ELTE Lendület Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Anne Kopp
- Junior Research Group for Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Mario Hebecker
- Junior Research Group for Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Barbara Uzonyi
- MTA-ELTE Immunology Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Mihály Józsi
- MTA-ELTE Lendület Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
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50
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Daigo K, Inforzato A, Barajon I, Garlanda C, Bottazzi B, Meri S, Mantovani A. Pentraxins in the activation and regulation of innate immunity. Immunol Rev 2017; 274:202-217. [PMID: 27782337 DOI: 10.1111/imr.12476] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Humoral fluid phase pattern recognition molecules (PRMs) are a key component of the activation and regulation of innate immunity. Humoral PRMs are diverse. We focused on the long pentraxin PTX3 as a paradigmatic example of fluid phase PRMs. PTX3 acts as a functional ancestor of antibodies and plays a non-redundant role in resistance against selected microbes in mouse and man and in the regulation of inflammation. This molecule interacts with complement components, thus modulating complement activation. In particular, PTX3 regulates complement-driven macrophage-mediated tumor progression, acting as an extrinsic oncosuppressor in preclinical models and selected human tumors. Evidence collected over the years suggests that PTX3 is a biomarker and potential therapeutic agent in humans, and pave the way to translation of this molecule into the clinic.
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Affiliation(s)
- Kenji Daigo
- Department of Inflammation and Immunology, Humanitas Clinical and Research Center, Rozzano (Milan), Italy
| | - Antonio Inforzato
- Department of Inflammation and Immunology, Humanitas Clinical and Research Center, Rozzano (Milan), Italy.,Department of Medical Biotechnologies and Translational Medicine, University of Milan, Italy
| | | | - Cecilia Garlanda
- Department of Inflammation and Immunology, Humanitas Clinical and Research Center, Rozzano (Milan), Italy
| | - Barbara Bottazzi
- Department of Inflammation and Immunology, Humanitas Clinical and Research Center, Rozzano (Milan), Italy
| | - Seppo Meri
- Immunobiology Research Program, Research Programs Unit, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki , Helsinki , Finland
| | - Alberto Mantovani
- Department of Inflammation and Immunology, Humanitas Clinical and Research Center, Rozzano (Milan), Italy.,Humanitas University, Rozzano, Italy
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