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Cavalcante P, Mantegazza R, Antozzi C. Targeting autoimmune mechanisms by precision medicine in Myasthenia Gravis. Front Immunol 2024; 15:1404191. [PMID: 38903526 PMCID: PMC11187261 DOI: 10.3389/fimmu.2024.1404191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 05/24/2024] [Indexed: 06/22/2024] Open
Abstract
Myasthenia Gravis (MG) is a chronic disabling autoimmune disease caused by autoantibodies to the neuromuscular junction (NMJ), characterized clinically by fluctuating weakness and early fatigability of ocular, skeletal and bulbar muscles. Despite being commonly considered a prototypic autoimmune disorder, MG is a complex and heterogeneous condition, presenting with variable clinical phenotypes, likely due to distinct pathophysiological settings related with different immunoreactivities, symptoms' distribution, disease severity, age at onset, thymic histopathology and response to therapies. Current treatment of MG based on international consensus guidelines allows to effectively control symptoms, but most patients do not reach complete stable remission and require life-long immunosuppressive (IS) therapies. Moreover, a proportion of them is refractory to conventional IS treatment, highlighting the need for more specific and tailored strategies. Precision medicine is a new frontier of medicine that promises to greatly increase therapeutic success in several diseases, including autoimmune conditions. In MG, B cell activation, antibody recycling and NMJ damage by the complement system are crucial mechanisms, and their targeting by innovative biological drugs has been proven to be effective and safe in clinical trials. The switch from conventional IS to novel precision medicine approaches based on these drugs could prospectively and significantly improve MG care. In this review, we provide an overview of key immunopathogenetic processes underlying MG, and discuss on emerging biological drugs targeting them. We also discuss on future direction of research to address the need for patients' stratification in endotypes according with genetic and molecular biomarkers for successful clinical decision making within precision medicine workflow.
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Affiliation(s)
- Paola Cavalcante
- Neurology 4 – Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Renato Mantegazza
- Neurology 4 – Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Carlo Antozzi
- Neurology 4 – Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Immunotherapy and Apheresis Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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2
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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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3
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Pimenta-Lopes C, Sánchez-de-Diego C, Deber A, Egea-Cortés A, Valer JA, Alcalá A, Méndez-Lucas A, Esteve-Codina A, Rosa JL, Ventura F. Inhibition of C5AR1 impairs osteoclast mobilization and prevents bone loss. Mol Ther 2023; 31:2507-2523. [PMID: 37143324 PMCID: PMC10422003 DOI: 10.1016/j.ymthe.2023.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/22/2022] [Accepted: 04/28/2023] [Indexed: 05/06/2023] Open
Abstract
Age-related and chemotherapy-induced bone loss depends on cellular senescence and the cell secretory phenotype. However, the factors secreted in the senescent microenvironment that contribute to bone loss remain elusive. Here, we report a central role for the inflammatory alternative complement system in skeletal bone loss. Through transcriptomic analysis of bone samples, we identified complement factor D, a rate-limiting factor of the alternative pathway of complement, which is among the most responsive factors to chemotherapy or estrogen deficiency. We show that osteoblasts and osteocytes are major inducers of complement activation, while monocytes and osteoclasts are their primary targets. Genetic deletion of C5ar1, the receptor of the anaphylatoxin C5a, or treatment with a C5AR1 inhibitor reduced monocyte chemotaxis and osteoclast differentiation. Moreover, genetic deficiency or inhibition of C5AR1 partially prevented bone loss and osteoclastogenesis upon chemotherapy or ovariectomy. Altogether, these lines of evidence support the idea that inhibition of alternative complement pathways may have some therapeutic benefit in osteopenic disorders.
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Affiliation(s)
- Carolina Pimenta-Lopes
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Cristina Sánchez-de-Diego
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Alexandre Deber
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Andrea Egea-Cortés
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - José Antonio Valer
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Albert Alcalá
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Andrés Méndez-Lucas
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science & Technology, 08028 Barcelona, Spain; Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Jose Luis Rosa
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Francesc Ventura
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain.
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4
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Biomarkers and laboratory assessments for monitoring the treatment of patients with paroxysmal nocturnal hemoglobinuria: Differences between terminal and proximal complement inhibition. Blood Rev 2023; 59:101041. [PMID: 36732204 DOI: 10.1016/j.blre.2023.101041] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/15/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening, acquired disease in which blood cells lacking complement regulatory proteins are destroyed because of uncontrolled complement activity. Since 2007, terminal complement inhibitors have revolutionized the treatment of this disease. However, patients treated with these inhibitors can still experience anemia because of C3-mediated extravascular hemolysis and clinically relevant levels of breakthrough or residual intravascular hemolysis. Proximal complement inhibitors, which are only just beginning to emerge, have the potential to address this problem by targeting components of the pathway upstream of C5, thereby protecting patients against both intra- and extravascular hemolysis. In this review, we describe different biomarkers that can be used to monitor complement pathway blockade and discuss key laboratory assessments for evaluating treatment efficacy. We also consider how these assessments are affected by each class of inhibitor and highlight how evolving treatment goals may influence the relative importance of these assessments.
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5
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Brandwijk RJMGE, Michels MAHM, van Rossum M, de Nooijer AH, Nilsson PH, de Bruin WCC, Toonen EJM. Pitfalls in complement analysis: A systematic literature review of assessing complement activation. Front Immunol 2022; 13:1007102. [PMID: 36330514 PMCID: PMC9623276 DOI: 10.3389/fimmu.2022.1007102] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background The complement system is an essential component of our innate defense and plays a vital role in the pathogenesis of many diseases. Assessment of complement activation is critical in monitoring both disease progression and response to therapy. Complement analysis requires accurate and standardized sampling and assay procedures, which has proven to be challenging. Objective We performed a systematic analysis of the current methods used to assess complement components and reviewed whether the identified studies performed their complement measurements according to the recommended practice regarding pre-analytical sample handling and assay technique. Results are supplemented with own data regarding the assessment of key complement biomarkers to illustrate the importance of accurate sampling and measuring of complement components. Methods A literature search using the Pubmed/MEDLINE database was performed focusing on studies measuring the key complement components C3, C5 and/or their split products and/or the soluble variant of the terminal C5b-9 complement complex (sTCC) in human blood samples that were published between February 2017 and February 2022. The identified studies were reviewed whether they had used the correct sample type and techniques for their analyses. Results A total of 92 out of 376 studies were selected for full-text analysis. Forty-five studies (49%) were identified as using the correct sample type and techniques for their complement analyses, while 25 studies (27%) did not use the correct sample type or technique. For 22 studies (24%), it was not specified which sample type was used. Conclusion A substantial part of the reviewed studies did not use the appropriate sample type for assessing complement activation or did not mention which sample type was used. This deviation from the standardized procedure can lead to misinterpretation of complement biomarker levels and hampers proper comparison of complement measurements between studies. Therefore, this study underlines the necessity of general guidelines for accurate and standardized complement analysis
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Affiliation(s)
| | - Marloes A. H. M. Michels
- Radboud Institute for Molecular Life Sciences, Department of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, Nijmegen, Netherlands
| | - Mara van Rossum
- R&D Department, Hycult Biotechnology b.v., Uden, Netherlands
| | - Aline H. de Nooijer
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Per H. Nilsson
- Department of Immunology, University of Oslo and Oslo University Hospital Rikshospitalet, Oslo, Norway
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | | | - Erik J. M. Toonen
- R&D Department, Hycult Biotechnology b.v., Uden, Netherlands
- *Correspondence: Erik J. M. Toonen,
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Waheed W, Newman E, Aboukhatwa M, Moin M, Tandan R. Practical Management for Use of Eculizumab in the Treatment of Severe, Refractory, Non-Thymomatous, AChR + Generalized Myasthenia Gravis: A Systematic Review. Ther Clin Risk Manag 2022; 18:699-719. [PMID: 35855752 PMCID: PMC9288180 DOI: 10.2147/tcrm.s266031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022] Open
Abstract
Myasthenia gravis (MG) is a rare autoimmune disorder caused by specific autoantibodies at the neuromuscular junction. MG is classified by the antigen specificity of these antibodies. Acetylcholine receptor (AChR) antibodies are the most common type (74–88%), followed by anti-muscle specific kinase (MuSK) and other antibodies. While all these antibodies lead to neuromuscular transmission failure, the immuno-pathogenic mechanisms are distinct. Complement activation is a primary driver of AChR antibody-positive MG (AChR+ MG) pathogenesis. This leads to the formation of the membrane attack complex and destruction of AChR receptors and the postsynaptic membrane resulting in impaired neurotransmission and muscle weakness characteristic of MG. Broad-based immune-suppressants like corticosteroids are effective in controlling MG; however, their long-term use can be associated with significant adverse effects. Advances in translational research have led to the development of more directed therapeutic agents that are likely to alter the future of MG treatment. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and is approved for use in generalized MG. In this review, we discuss the pathophysiology of MG; the therapeutic efficacy and tolerability of eculizumab, as well as the practical guidelines for its use in MG; future studies exploring the role of eculizumab in different stages and subtypes of MG subtypes; the optimal duration of therapy and its discontinuation; the characterization of non-responder patients; and the use of biomarkers for monitoring therapy are highlighted. Based on the pathophysiologic mechanisms, emerging therapies and new therapeutic targets are also reviewed.
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Affiliation(s)
- Waqar Waheed
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
| | - Eric Newman
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
| | - Marwa Aboukhatwa
- Pharmacotherapy Department, University of Vermont Medical Center, Burlington, VT, USA
| | - Maryam Moin
- Department of Neurology, University of Illinois College of Medicine, Peoria, IL, USA
| | - Rup Tandan
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
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7
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Complement Activation Profile in Myasthenia Gravis Patients: Perspectives for Tailoring Anti-Complement Therapy. Biomedicines 2022; 10:biomedicines10061360. [PMID: 35740382 PMCID: PMC9220000 DOI: 10.3390/biomedicines10061360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 12/03/2022] Open
Abstract
The complement system plays a key role in myasthenia gravis (MG). Anti-complement drugs are emerging as effective therapies to treat anti-acetylcholine receptor (AChR) antibody-positive MG patients, though their usage is still limited by the high costs. Here, we searched for plasma complement proteins as indicators of complement activation status in AChR-MG patients, and potential biomarkers for tailoring anti-complement therapy in MG. Plasma was collected from AChR-MG and MuSK-MG patients, and healthy controls. Multiplex immunoassays and ELISA were used to quantify a panel of complement components (C1Q, C2, C3, C4, C5, Factor B, Factor H, MBL, and properdin) and activation products (C4b, C3b, C5a, and C5b-9), of classical, alternative and lectin pathways. C2 and C5 levels were significantly reduced, and C3, C3b, and C5a increased, in plasma of AChR-MG, but not MuSK-MG, patients compared to controls. This protein profile was indicative of complement activation. We obtained sensitivity and specificity performance results suggesting plasma C2, C3, C3b, and C5 as biomarkers for AChR-MG. Our findings reveal a plasma complement “C2, C3, C5, C3b, and C5a” profile associated with AChR-MG to be further investigated as a biomarker of complement activation status in AChR-MG patients, opening new perspectives for tailoring of anti-complement therapies to improve the disease treatment.
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8
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Frazer-Abel A, Kirschfink M, Prohászka Z. Expanding Horizons in Complement Analysis and Quality Control. Front Immunol 2021; 12:697313. [PMID: 34434189 PMCID: PMC8381195 DOI: 10.3389/fimmu.2021.697313] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/19/2021] [Indexed: 01/09/2023] Open
Abstract
Complement not only plays a key role in host microbial defense but also modulates the adaptive immune response through modification of T- and B-cell reactivity. Moreover, a normally functioning complement system participates in hematopoiesis, reproduction, lipid metabolism, and tissue regeneration. Because of its powerful inflammatory potential, multiple regulatory proteins are needed to prevent potential tissue damage. In clinical practice, dysregulation and overactivation of the complement system are major causes of a variety of inflammatory and autoimmune diseases ranging from nephropathies, age-related macular degeneration (AMD), and systemic lupus erythematosus (SLE) to graft rejection, sepsis, and multi-organ failure. The clinical importance is reflected by the recent development of multiple drugs targeting complement with a broad spectrum of indications. The recognition of the role of complement in diverse diseases and the advent of complement therapeutics has increased the number of laboratories and suppliers entering the field. This has highlighted the need for reliable complement testing. The relatively rapid expansion in complement testing has presented challenges for a previously niche field. This is exemplified by the issue of cross-reactivity of complement-directed antibodies and by the challenges of the poor stability of many of the complement analytes. The complex nature of complement testing and increasing clinical demand has been met in the last decade by efforts to improve the standardization among laboratories. Initiated by the IUIS/ICS Committee for the Standardization and Quality Assessment in Complement Measurements 14 rounds of external quality assessment since 2010 resulted in improvements in the consistency of testing across participating institutions, while extending the global reach of the efforts to more than 200 laboratories in 30 countries. Worldwide trends of assay availability, usage, and analytical performance are summarized based on the past years’ experiences. Progress in complement analysis has been facilitated by the quality assessment and standardization efforts that now allow complement testing to provide a comprehensive insight into deficiencies and the activation state of the system. This in turn enables clinicians to better define disease severity, evolution, and response to therapy.
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Affiliation(s)
| | | | - Zoltán Prohászka
- Department of Medicine and Hematology, Research Laboratory Semmelweis University, Budapest, Hungary
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9
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Abstract
The complement cascade is an evolutionary ancient innate immune defense system, playing a major role in the defense against infections. Its function in maintaining host homeostasis on activated cells has been emphasized by the crucial role of its overactivation in ever growing number of diseases, such as atypical hemolytic uremic syndrome (aHUS), autoimmune diseases as systemic lupus erythematosus (SLE), C3 glomerulopathies (C3GN), age-related macular degeneration (AMD), graft rejection, Alzheimer disease, and cancer, to name just a few. The last decade of research on complement has extended its implication in many pathological processes, offering new insights to potential therapeutic targets and asserting the necessity of reliable, sensitive, specific, accurate, and reproducible biomarkers to decipher complement role in pathology. We need to evaluate accurately which pathway or role should be targeted pharmacologically, and optimize treatment efficacy versus toxicity. This chapter is an introduction to the role of complement in human diseases and the use of complement-related biomarkers in the clinical practice. It is a part of a book intending to give reliable and standardized methods to evaluate complement according to nowadays needs and knowledge.
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10
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Zarantonello A, Pedersen H, Laursen NS, Andersen GR. Nanobodies Provide Insight into the Molecular Mechanisms of the Complement Cascade and Offer New Therapeutic Strategies. Biomolecules 2021; 11:biom11020298. [PMID: 33671302 PMCID: PMC7922070 DOI: 10.3390/biom11020298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 01/22/2023] Open
Abstract
The complement system is part of the innate immune response, where it provides immediate protection from infectious agents and plays a fundamental role in homeostasis. Complement dysregulation occurs in several diseases, where the tightly regulated proteolytic cascade turns offensive. Prominent examples are atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria and Alzheimer’s disease. Therapeutic intervention targeting complement activation may allow treatment of such debilitating diseases. In this review, we describe a panel of complement targeting nanobodies that allow modulation at different steps of the proteolytic cascade, from the activation of the C1 complex in the classical pathway to formation of the C5 convertase in the terminal pathway. Thorough structural and functional characterization has provided a deep mechanistic understanding of the mode of inhibition for each of the nanobodies. These complement specific nanobodies are novel powerful probes for basic research and offer new opportunities for in vivo complement modulation.
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Affiliation(s)
- Alessandra Zarantonello
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; (A.Z.); (H.P.)
| | - Henrik Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; (A.Z.); (H.P.)
| | - Nick S. Laursen
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark;
| | - Gregers R. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; (A.Z.); (H.P.)
- Correspondence: ; Tel.: +45-30256646
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11
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Koopman JJE, van Essen MF, Rennke HG, de Vries APJ, van Kooten C. Deposition of the Membrane Attack Complex in Healthy and Diseased Human Kidneys. Front Immunol 2021; 11:599974. [PMID: 33643288 PMCID: PMC7906018 DOI: 10.3389/fimmu.2020.599974] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.
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Affiliation(s)
- Jacob J E Koopman
- Division of Renal Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Mieke F van Essen
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Helmut G Rennke
- Division of Renal Pathology, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Aiko P J de Vries
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Cees van Kooten
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
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12
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Mantegazza R, Vanoli F, Frangiamore R, Cavalcante P. Complement Inhibition for the Treatment of Myasthenia Gravis. Immunotargets Ther 2020; 9:317-331. [PMID: 33365280 PMCID: PMC7751298 DOI: 10.2147/itt.s261414] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 12/02/2020] [Indexed: 12/11/2022] Open
Abstract
Generalized myasthenia gravis (gMG) is a rare autoimmune disorder affecting the neuromuscular junction (NMJ). Approximately 80-90% of patients display antibodies directed against the nicotinic acetylcholine receptor (AChR). A major drive of AChR antibody-positive MG pathology is represented by complement activation. The role of the complement cascade has been largely demonstrated in patients and in MG animal models. Complement activation at the NMJ leads to focal lysis of the post-synaptic membrane, disruption of the characteristic folds, and reduction of AChR. Given that the complement system works as an activation cascade, there are many potential targets that can be considered for therapeutic intervention. Preclinical studies have confirmed the efficacy of complement inhibition in ameliorating MG symptoms. Eculizumab, an antibody directed towards C5, has recently been approved for the treatment of AChR antibody-positive gMG. Other complement inhibitors, targeting C5 as well, are currently under phase III study. Complement inhibitors, however, may present prohibitive costs. Therefore, the identification of a subset of patients more or less prone to respond to such therapies would be beneficial. For such purpose, there is a critical need to identify possible biomarkers predictive of therapeutic response, a field not yet sufficiently explored in MG. This review aims to give an overview of the complement cascade involvement in MG, the evolution of complement-inhibiting therapies and possible biomarkers useful to tailor and monitor complement-directed therapies.
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Affiliation(s)
- Renato Mantegazza
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Fiammetta Vanoli
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Rita Frangiamore
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Paola Cavalcante
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Dalakas MC, Alexopoulos H, Spaeth PJ. Complement in neurological disorders and emerging complement-targeted therapeutics. Nat Rev Neurol 2020; 16:601-617. [PMID: 33005040 PMCID: PMC7528717 DOI: 10.1038/s41582-020-0400-0] [Citation(s) in RCA: 171] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 12/30/2022]
Abstract
The complement system consists of a network of plasma and membrane proteins that modulate tissue homeostasis and contribute to immune surveillance by interacting with the innate and adaptive immune systems. Dysregulation, impairment or inadvertent activation of complement components contribute to the pathogenesis of some autoimmune neurological disorders and could even contribute to neurodegenerative diseases. In this Review, we summarize current knowledge about the main functions of the complement pathways and the involvement of complement in neurological disorders. We describe the complex network of complement proteins that target muscle, the neuromuscular junction, peripheral nerves, the spinal cord or the brain and discuss the autoimmune mechanisms of complement-mediated myopathies, myasthenia, peripheral neuropathies, neuromyelitis and other CNS disorders. We also consider the emerging role of complement in some neurodegenerative diseases, such as Alzheimer disease, amyotrophic lateral sclerosis and even schizophrenia. Finally, we provide an overview of the latest complement-targeted immunotherapies including monoclonal antibodies, fusion proteins and peptidomimetics that have been approved, that are undergoing phase I–III clinical trials or that show promise for the treatment of neurological conditions that respond poorly to existing immunotherapies. In this Review, Dalakas et al. discuss the complement system, the role it plays in autoimmune neurological disease and neurodegenerative disease, and provide an overview of the latest therapeutics that target complement and that can be used for or have potential in neurological disorders. Complement has an important physiological role in host immune defences and tissue remodelling. The physiological role of complement extends to the regulation of synaptic development. Complement has a key pathophysiological role in autoimmune neurological diseases and mediates the actions of pathogenic autoantibodies, such as acetylcholine receptor antibodies and aquaporin 4 antibodies. For some autoimmune neurological diseases, such as myasthenia gravis and neuromyelitis optica spectrum disorders, approved complement-targeted treatments are now available. Complement also seems to be of pathogenic relevance in neurodegenerative diseases such as Alzheimer disease, in which innate immune-driven inflammation is receiving increasing attention. The field of complement-targeted therapeutics is rapidly expanding, with several FDA-approved agents and others currently in phase II and phase III clinical trials.
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Affiliation(s)
- Marinos C Dalakas
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA. .,Neuroimmunology Unit, Department of Pathophysiology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
| | - Harry Alexopoulos
- Neuroimmunology Unit, Department of Pathophysiology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Peter J Spaeth
- Institute of Pharmacology, University of Bern, Bern, Switzerland
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