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Xu J, Chen L, Pang S, Zhang Q, Deng S, Zhu J, Chen X, Langford PR, Huang Q, Zhou R, Li L. HylS', a fragment of truncated hyaluronidase of Streptococcus suis, contributes to immune evasion by interaction with host complement factor C3b. Virulence 2024; 15:2306691. [PMID: 38251716 PMCID: PMC10854370 DOI: 10.1080/21505594.2024.2306691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Pathogenic bacteria have evolved many strategies to evade surveillance and attack by complements. Streptococcus suis is an important zoonotic pathogen that infects humans and pigs. Hyaluronidase (HylA) has been reported to be a potential virulence factor of S. suis. However, in this study, it was discovered that the genomic region encoding HylA of the virulent S. suis strain SC19 and other ST1 strains was truncated into four fragments when aligned with a strain containing intact HylA and possessing hyaluronidase activity. As a result, SC19 had no hyaluronidase activity, but one truncated HylA fragment, designated as HylS,' directly interacted with complement C3b, as confirmed by western ligand blotting, pull-down, and ELISA assays. The deposition of C3b and membrane attack complex (MAC) formation on the surface of a HylS'-deleted mutant (ΔhylS') was significantly increased compared to wild-type SC19. In human sera and whole blood, ΔhylS' survival was significantly reduced compared to that in SC19. The resistance of ΔhylS' to macrophages and human polymorphonuclear neutrophil PMNs also decreased. In a mouse infection model, ΔhylS' showed reduced lethality and lower bacterial load in the organs compared to that of SC19. We conclude that the truncated hyaluronidase HylS' fragment contributes to complement evasion and the pathogenesis of S. suis.
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Affiliation(s)
- Jiajia Xu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Long Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Siqi Pang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Qiuhong Zhang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Simin Deng
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Jiaqi Zhu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Xiabing Chen
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, Hubei, China
| | - Paul R Langford
- Section of Paediatric Infectious Disease, Imperial College London, St Mary’s Campus, London, UK
| | - Qi Huang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
- International Research Center for Animal Disease, Ministry of Science and Technology of the People’s Republic of China, Wuhan, Hubei, China
| | - Rui Zhou
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
- International Research Center for Animal Disease, Ministry of Science and Technology of the People’s Republic of China, Wuhan, Hubei, China
| | - Lu Li
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
- International Research Center for Animal Disease, Ministry of Science and Technology of the People’s Republic of China, Wuhan, Hubei, China
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2
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Nguyen H, Podolnikova NP, Ugarova TP, Wang X. α MI-domain of integrin Mac-1 binds the cytokine pleiotrophin using multiple mechanisms. Structure 2024; 32:1184-1196.e4. [PMID: 38729161 PMCID: PMC11316656 DOI: 10.1016/j.str.2024.04.013] [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: 01/24/2024] [Revised: 03/21/2024] [Accepted: 04/15/2024] [Indexed: 05/12/2024]
Abstract
The integrin Mac-1 (αMβ2, CD11b/CD18, CR3) is an adhesion receptor expressed on macrophages and neutrophils. Mac-1 is also a promiscuous integrin that binds a diverse set of ligands through its αMI-domain. However, the binding mechanism of most ligands remains unclear. We have characterized the interaction of αMI-domain with the cytokine pleiotrophin (PTN), a protein known to bind αMI-domain and induce Mac-1-mediated cell adhesion and migration. Our data show that PTN's N-terminal domain binds a unique site near the N- and C-termini of the αMI-domain using a metal-independent mechanism. However, a stronger interaction is achieved when an acidic amino acid in a zwitterionic motif in PTN's C-terminal domain chelates the divalent cation in the metal ion-dependent adhesion site of active αMI-domain. These results indicate that αMI-domain can bind ligands using multiple mechanisms and that the active αMI-domain has a preference for motifs containing both positively and negatively charged amino acids.
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Affiliation(s)
- Hoa Nguyen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281, USA
| | | | - Tatiana P Ugarova
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Xu Wang
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281, USA.
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3
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Cook AD, Carrington M, Higgins MK. Molecular mechanism of complement inhibition by the trypanosome receptor ISG65. eLife 2024; 12:RP88960. [PMID: 38655765 PMCID: PMC11042801 DOI: 10.7554/elife.88960] [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] [Indexed: 04/26/2024] Open
Abstract
African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade.
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Affiliation(s)
- Alexander D Cook
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of OxfordOxfordUnited Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of CambridgeCambridgeUnited Kingdom
| | - Matthew K Higgins
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of OxfordOxfordUnited Kingdom
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4
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El Mahdaoui S, Hansen MM, von Essen MR, Hvalkof VH, Holm Hansen R, Mahler MR, Jennum P, Sellebjerg F, Romme Christensen J. CD11c + B cells in relapsing-remitting multiple sclerosis and effects of anti-CD20 therapy. Ann Clin Transl Neurol 2024; 11:926-937. [PMID: 38332555 PMCID: PMC11021659 DOI: 10.1002/acn3.52009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 02/10/2024] Open
Abstract
OBJECTIVES B cells are important in the pathogenesis of multiple sclerosis. It is yet unknown which subsets may be involved, but atypical B cells have been proposed as mediators of autoimmunity. In this study, we investigated differences in B-cell subsets between controls and patients with untreated and anti-CD20-treated multiple sclerosis. METHODS We recruited 155 participants for an exploratory cohort comprising peripheral blood and cerebrospinal fluid, and a validation cohort comprising peripheral blood. Flow cytometry was used to characterize B-cell phenotypes and effector functions of CD11c+ atypical B cells. RESULTS There were no differences in circulating B cells between controls and untreated multiple sclerosis. As expected, anti-CD20-treated patients had a markedly lower B-cell count. Of B cells remaining after treatment, we observed higher proportions of CD11c+ B cells and plasmablasts. CD11c+ B cells were expanded in cerebrospinal fluid compared to peripheral blood in controls and untreated multiple sclerosis. Surprisingly, the proportion of CD11c+ cerebrospinal fluid B cells was higher in controls and after anti-CD20 therapy than in untreated multiple sclerosis. Apart from the presence of plasmablasts, the cerebrospinal fluid B-cell composition after anti-CD20 therapy resembled that of controls. CD11c+ B cells demonstrated a high potential for both proinflammatory and regulatory cytokine production. INTERPRETATION The study demonstrates that CD11c+ B cells and plasmablasts are less efficiently depleted by anti-CD20 therapy, and that CD11c+ B cells comprise a phenotypically and functionally distinct, albeit heterogenous, B-cell subset with the capacity of exerting both proinflammatory and regulatory functions.
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Affiliation(s)
- Sahla El Mahdaoui
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Marie Mathilde Hansen
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Marina Rode von Essen
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Victoria Hyslop Hvalkof
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Rikke Holm Hansen
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Mie Reith Mahler
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
| | - Poul Jennum
- Department of NeurologyDanish Center for Sleep Medicine, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
- Department of Clinical MedicineUniversity of CopenhagenCopenhagen2200Denmark
| | - Finn Sellebjerg
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
- Department of Clinical MedicineUniversity of CopenhagenCopenhagen2200Denmark
| | - Jeppe Romme Christensen
- Department of NeurologyDanish Multiple Sclerosis Center, Copenhagen University Hospital – RigshospitaletGlostrup2600Denmark
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Bendapudi PK, Nazeen S, Ryu J, Söylemez O, Robbins A, Rouaisnel B, O’Neil JK, Pokhriyal R, Yang M, Colling M, Pasko B, Bouzinier M, Tomczak L, Collier L, Barrios D, Ram S, Toth-Petroczy A, Krier J, Fieg E, Dzik WH, Hudspeth JC, Pozdnyakova O, Nardi V, Knight J, Maas R, Sunyaev S, Losman JA. Low-frequency inherited complement receptor variants are associated with purpura fulminans. Blood 2024; 143:1032-1044. [PMID: 38096369 PMCID: PMC10950473 DOI: 10.1182/blood.2023021231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 11/15/2023] [Indexed: 03/16/2024] Open
Abstract
ABSTRACT Extreme disease phenotypes can provide key insights into the pathophysiology of common conditions, but studying such cases is challenging due to their rarity and the limited statistical power of existing methods. Herein, we used a novel approach to pathway-based mutational burden testing, the rare variant trend test (RVTT), to investigate genetic risk factors for an extreme form of sepsis-induced coagulopathy, infectious purpura fulminans (PF). In addition to prospective patient sample collection, we electronically screened over 10.4 million medical records from 4 large hospital systems and identified historical cases of PF for which archived specimens were available to perform germline whole-exome sequencing. We found a significantly increased burden of low-frequency, putatively function-altering variants in the complement system in patients with PF compared with unselected patients with sepsis (P = .01). A multivariable logistic regression analysis found that the number of complement system variants per patient was independently associated with PF after controlling for age, sex, and disease acuity (P = .01). Functional characterization of PF-associated variants in the immunomodulatory complement receptors CR3 and CR4 revealed that they result in partial or complete loss of anti-inflammatory CR3 function and/or gain of proinflammatory CR4 function. Taken together, these findings suggest that inherited defects in CR3 and CR4 predispose to the maladaptive hyperinflammation that characterizes severe sepsis with coagulopathy.
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Affiliation(s)
- Pavan K. Bendapudi
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
- Division of Hematology and Blood Transfusion Service, Massachusetts General Hospital, Boston, MA
- Harvard Medical School, Boston, MA
| | - Sumaiya Nazeen
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Justine Ryu
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
- Harvard Medical School, Boston, MA
| | - Onuralp Söylemez
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Alissa Robbins
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Betty Rouaisnel
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Jillian K. O’Neil
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Ruchika Pokhriyal
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Moua Yang
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
- Harvard Medical School, Boston, MA
| | - Meaghan Colling
- Division of Hematology and Blood Transfusion Service, Massachusetts General Hospital, Boston, MA
- Harvard Medical School, Boston, MA
| | - Bryce Pasko
- Department of Pathology, University of Colorado School of Medicine, Aurora, CO
| | - Michael Bouzinier
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Lindsay Tomczak
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
| | - Lindsay Collier
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
| | - David Barrios
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA
- Harvard Medical School, Boston, MA
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA
| | - Agnes Toth-Petroczy
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Joel Krier
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Elizabeth Fieg
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Walter H. Dzik
- Division of Hematology and Blood Transfusion Service, Massachusetts General Hospital, Boston, MA
- Harvard Medical School, Boston, MA
| | - James C. Hudspeth
- Department of Medicine, Boston Medical Center, Boston, MA
- Boston University School of Medicine, Boston, MA
| | - Olga Pozdnyakova
- Harvard Medical School, Boston, MA
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA
| | - Valentina Nardi
- Harvard Medical School, Boston, MA
- Department of Pathology, Massachusetts General Hospital, Boston, MA
| | - James Knight
- Yale Center for Genome Analysis, Yale University, New Haven, CT
| | - Richard Maas
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Shamil Sunyaev
- Harvard Medical School, Boston, MA
- Division of Genomic Medicine, Brigham and Women’s Hospital, Boston, MA
| | - Julie-Aurore Losman
- Harvard Medical School, Boston, MA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women’s Hospital, Boston, MA
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Juul-Madsen K, Parbo P, Ismail R, Ovesen PL, Schmidt V, Madsen LS, Thyrsted J, Gierl S, Breum M, Larsen A, Andersen MN, Romero-Ramos M, Holm CK, Andersen GR, Zhao H, Schuck P, Nygaard JV, Sutherland DS, Eskildsen SF, Willnow TE, Brooks DJ, Vorup-Jensen T. Amyloid-β aggregates activate peripheral monocytes in mild cognitive impairment. Nat Commun 2024; 15:1224. [PMID: 38336934 PMCID: PMC10858199 DOI: 10.1038/s41467-024-45627-y] [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: 12/21/2022] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
The peripheral immune system is important in neurodegenerative diseases, both in protecting and inflaming the brain, but the underlying mechanisms remain elusive. Alzheimer's Disease is commonly preceded by a prodromal period. Here, we report the presence of large Aβ aggregates in plasma from patients with mild cognitive impairment (n = 38). The aggregates are associated with low level Alzheimer's Disease-like brain pathology as observed by 11C-PiB PET and 18F-FTP PET and lowered CD18-rich monocytes. We characterize complement receptor 4 as a strong binder of amyloids and show Aβ aggregates are preferentially phagocytosed and stimulate lysosomal activity through this receptor in stem cell-derived microglia. KIM127 integrin activation in monocytes promotes size selective phagocytosis of Aβ. Hydrodynamic calculations suggest Aβ aggregates associate with vessel walls of the cortical capillaries. In turn, we hypothesize aggregates may provide an adhesion substrate for recruiting CD18-rich monocytes into the cortex. Our results support a role for complement receptor 4 in regulating amyloid homeostasis.
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Affiliation(s)
- Kristian Juul-Madsen
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
- Max-Delbrueck-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Peter Parbo
- Department of Nuclear Medicine, Odense University Hospital, J. B. Winsløws Vej 4, DK-5000, Odense C, Denmark
| | - Rola Ismail
- Department of Nuclear medicine and PET, Vejle Hospital, Beriderbakken 4, DK-7100, Vejle, Denmark
| | - Peter L Ovesen
- Max-Delbrueck-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Vanessa Schmidt
- Max-Delbrueck-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Lasse S Madsen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 11, DK-8200, Aarhus N, Denmark
- Center of Functionally Integrative Neuroscience, Aarhus University and Aarhus University Hospital, Building 1710, Universitetsbyen 3, DK-8200, Aarhus C, Denmark
| | - Jacob Thyrsted
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
| | - Sarah Gierl
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
| | - Mihaela Breum
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
| | - Agnete Larsen
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
| | - Morten N Andersen
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 11, DK-8200, Aarhus N, Denmark
- Department of Hematology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
| | - Marina Romero-Ramos
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
- NEURODIN AU IDEAS Center, Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8200, Aarhus C, Denmark
| | - Christian K Holm
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Huaying Zhao
- Laboratory of Dynamics and Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, Building 31, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Peter Schuck
- Laboratory of Dynamics and Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, Building 31, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Jens V Nygaard
- Department of Biological and Chemical Engineering, Aarhus University, Gustav Wieds vej 10 D, DK-8200, Aarhus C, Denmark
| | - Duncan S Sutherland
- Interdisiciplinary Nanoscience Center, Aarhus University, The iNANO House, Gustav Wieds Vej 14, DK-8200, Aarhus C, Denmark
- Center for Cellular Signal Patterns, Aarhus University, The iNANO House, Gustav Wieds Vej 14, DK-8200, Aarhus C, Denmark
| | - Simon F Eskildsen
- Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 11, DK-8200, Aarhus N, Denmark
- Center of Functionally Integrative Neuroscience, Aarhus University and Aarhus University Hospital, Building 1710, Universitetsbyen 3, DK-8200, Aarhus C, Denmark
| | - Thomas E Willnow
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark
- Max-Delbrueck-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - David J Brooks
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200, Aarhus N, Denmark
- Department of Brain Sciences, Imperial College London, Burlington Danes, The Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
- Institute of Translational and Clinical Research, University of Newcastle, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Thomas Vorup-Jensen
- Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8000, Aarhus C, Denmark.
- NEURODIN AU IDEAS Center, Department of Biomedicine, Aarhus University, The Skou Building, Høegh-Guldbergs Gade 10, DK-8200, Aarhus C, Denmark.
- Interdisiciplinary Nanoscience Center, Aarhus University, The iNANO House, Gustav Wieds Vej 14, DK-8200, Aarhus C, Denmark.
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Nguyen H, Podolnikova NP, Ugarova TP, Wang X. α MI-domain of Integrin Mac-1 Binds the Cytokine Pleiotrophin Using Multiple Mechanisms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.578455. [PMID: 38352421 PMCID: PMC10862807 DOI: 10.1101/2024.02.01.578455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The integrin Mac-1 (αMβ2, CD11b/CD18, CR3) is an important adhesion receptor expressed on macrophages and neutrophils. Mac-1 is also the most promiscuous member of the integrin family that binds a diverse set of ligands through its αMI-domain. However, the binding mechanism of most ligands is not clear. We have determined the interaction of αMI-domain with the cytokine pleiotrophin (PTN), a cationic protein known to bind αMI-domain and induce Mac-1-mediated cell adhesion and migration. Our data show that PTN's N-terminal domain binds a unique site near the N- and C-termini of the αMI-domain using a metal-independent mechanism. However, stronger interaction is achieved when an acidic amino acid in a zwitterionic motif in PTN's C-terminal domain chelates the divalent cation in the metal ion-dependent adhesion site of the active αMI-domain. These results indicate that αMI-domain can bind ligands using multiple mechanisms, and suggest that active αMI-domain prefers acidic amino acids in zwitterionic motifs.
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Affiliation(s)
- Hoa Nguyen
- School of Molecular Sciences, Arizona State University, Tempe, Arizona
| | | | | | - Xu Wang
- School of Molecular Sciences, Arizona State University, Tempe, Arizona
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8
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Klaus T, Hieber C, Bros M, Grabbe S. Integrins in Health and Disease-Suitable Targets for Treatment? Cells 2024; 13:212. [PMID: 38334604 PMCID: PMC10854705 DOI: 10.3390/cells13030212] [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: 12/27/2023] [Revised: 01/13/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
Integrin receptors are heterodimeric surface receptors that play multiple roles regarding cell-cell communication, signaling, and migration. The four members of the β2 integrin subfamily are composed of an alternative α (CD11a-d) subunit, which determines the specific receptor properties, and a constant β (CD18) subunit. This review aims to present insight into the multiple immunological roles of integrin receptors, with a focus on β2 integrins that are specifically expressed by leukocytes. The pathophysiological role of β2 integrins is confirmed by the drastic phenotype of patients suffering from leukocyte adhesion deficiencies, most often resulting in severe recurrent infections and, at the same time, a predisposition for autoimmune diseases. So far, studies on the role of β2 integrins in vivo employed mice with a constitutive knockout of all β2 integrins or either family member, respectively, which complicated the differentiation between the direct and indirect effects of β2 integrin deficiency for distinct cell types. The recent generation and characterization of transgenic mice with a cell-type-specific knockdown of β2 integrins by our group has enabled the dissection of cell-specific roles of β2 integrins. Further, integrin receptors have been recognized as target receptors for the treatment of inflammatory diseases as well as tumor therapy. However, whereas both agonistic and antagonistic agents yielded beneficial effects in animal models, the success of clinical trials was limited in most cases and was associated with unwanted side effects. This unfavorable outcome is most probably related to the systemic effects of the used compounds on all leukocytes, thereby emphasizing the need to develop formulations that target distinct types of leukocytes to modulate β2 integrin activity for therapeutic applications.
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Affiliation(s)
| | | | | | - Stephan Grabbe
- Department of Dermatology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstraße 1, 55131 Mainz, Germany; (T.K.); (C.H.); (M.B.)
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9
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Heurich M, McCluskey G. Complement and coagulation crosstalk - Factor H in the spotlight. Immunobiology 2023; 228:152707. [PMID: 37633063 DOI: 10.1016/j.imbio.2023.152707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/02/2023] [Accepted: 07/10/2023] [Indexed: 08/28/2023]
Abstract
The immune complement and the coagulation systems are blood-based proteolytic cascades that are activated by pathway-specific triggers, based on protein-protein interactions and enzymatic cleavage reactions. Activation of these systems is finely balanced and controlled through specific regulatory mechanisms. The complement and coagulation systems are generally viewed as distinct, but have common evolutionary origins, and several interactions between these homologous systems have been reported. This complement and coagulation crosstalk can affect activation, amplification and regulatory functions in both systems. In this review, we summarize the literature on coagulation factors contributing to complement alternative pathway activation and regulation and highlight molecular interactions of the complement alternative pathway regulator factor H with several coagulation factors. We propose a mechanism where factor H interactions with coagulation factors may contribute to both complement and coagulation activation and regulation within the haemostatic system and fibrin clot microenvironment and introduce the emerging role of factor H as a modulator of coagulation. Finally, we discuss the potential impact of these protein interactions in diseases associated with factor H dysregulation or deficiency as well as evidence of coagulation dysfunction.
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Affiliation(s)
- Meike Heurich
- School of Pharmacy and Pharmaceutical Sciences, College of Biomedical and Life Sciences, Cardiff University, United Kingdom.
| | - Geneviève McCluskey
- Université Paris-Saclay, INSERM, Hémostase, Inflammation, Thrombose HITH U1176, 94276 Le Kremlin-Bicêtre, France
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10
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Kareem S, Jacob A, Mathew J, Quigg RJ, Alexander JJ. Complement: Functions, location and implications. Immunology 2023; 170:180-192. [PMID: 37222083 PMCID: PMC10524990 DOI: 10.1111/imm.13663] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 05/09/2023] [Indexed: 05/25/2023] Open
Abstract
The complement system, an arm of the innate immune system plays a critical role in both health and disease. The complement system is highly complex with dual possibilities, helping or hurting the host, depending on the location and local microenvironment. The traditionally known functions of complement include surveillance, pathogen recognition, immune complex trafficking, processing and pathogen elimination. The noncanonical functions of the complement system include their roles in development, differentiation, local homeostasis and other cellular functions. Complement proteins are present in both, the plasma and on the membranes. Complement activation occurs both extra- and intracellularly, which leads to considerable pleiotropy in their activity. In order to design more desirable and effective therapies, it is important to understand the different functions of complement, and its location-based and tissue-specific responses. This manuscript will provide a brief overview into the complex nature of the complement cascade, outlining some of their complement-independent functions, their effects at different locale, and their implication in disease settings.
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Affiliation(s)
- Samer Kareem
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - Alexander Jacob
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - John Mathew
- Department of Rheumatology, Christian Medical College, Vellore, India
| | - Richard J Quigg
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - Jessy J Alexander
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
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11
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Santos-López J, de la Paz K, Fernández FJ, Vega MC. Structural biology of complement receptors. Front Immunol 2023; 14:1239146. [PMID: 37753090 PMCID: PMC10518620 DOI: 10.3389/fimmu.2023.1239146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023] Open
Abstract
The complement system plays crucial roles in a wide breadth of immune and inflammatory processes and is frequently cited as an etiological or aggravating factor in many human diseases, from asthma to cancer. Complement receptors encompass at least eight proteins from four structural classes, orchestrating complement-mediated humoral and cellular effector responses and coordinating the complex cross-talk between innate and adaptive immunity. The progressive increase in understanding of the structural features of the main complement factors, activated proteolytic fragments, and their assemblies have spurred a renewed interest in deciphering their receptor complexes. In this review, we describe what is currently known about the structural biology of the complement receptors and their complexes with natural agonists and pharmacological antagonists. We highlight the fundamental concepts and the gray areas where issues and problems have been identified, including current research gaps. We seek to offer guidance into the structural biology of the complement system as structural information underlies fundamental and therapeutic research endeavors. Finally, we also indicate what we believe are potential developments in the field.
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Affiliation(s)
- Jorge Santos-López
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Karla de la Paz
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Research & Development, Abvance Biotech SL, Madrid, Spain
| | | | - M. Cristina Vega
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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12
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Tan Y, Huang J, Li D, Zou C, Liu D, Qin B. Single-cell RNA sequencing in dissecting microenvironment of age-related macular degeneration: Challenges and perspectives. Ageing Res Rev 2023; 90:102030. [PMID: 37549871 DOI: 10.1016/j.arr.2023.102030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 04/29/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in individuals over the age of 50 years, yet its etiology and pathogenesis largely remain uncovered. Single-cell RNA sequencing (scRNA-seq) technologies are recently developed and have a number of advantages over conventional bulk RNA sequencing techniques in uncovering the heterogeneity of complex microenvironments containing numerous cell types and cell communications during various biological processes. In this review, we summarize the latest discovered cellular components and regulatory mechanisms during AMD development revealed by scRNA-seq. In addition, we discuss the main challenges and future directions in exploring the pathophysiology of AMD equipped with single-cell technologies. Our review underscores the importance of multimodal single-cell platforms (such as single-cell spatiotemporal multi-omics and single-cell exosome omics) as new approaches for basic and clinical AMD research in identifying biomarker, characterizing cellular responses to drug treatment and environmental stimulation.
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Affiliation(s)
- Yao Tan
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Jianguo Huang
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Deshuang Li
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Chang Zou
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; School of Life and Health Sciences, The Chinese University of Kong Hong, Shenzhen 518000, Guangdong, China.
| | - Dongcheng Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China.
| | - Bo Qin
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; Aier School of Ophthalmology, Central South University, Changsha, China.
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13
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Lorentzen J, Olesen HG, Hansen AG, Thiel S, Birkelund S, Andersen CBF, Andersen GR. Trypanosoma brucei Invariant Surface gp65 Inhibits the Alternative Pathway of Complement by Accelerating C3b Degradation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:862-873. [PMID: 37466368 DOI: 10.4049/jimmunol.2300128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 06/30/2023] [Indexed: 07/20/2023]
Abstract
Trypanosomes are known to activate the complement system on their surface, but they control the cascade in a manner such that the cascade does not progress into the terminal pathway. It was recently reported that the invariant surface glycoprotein ISG65 from Trypanosoma brucei interacts reversibly with complement C3 and its degradation products, but the molecular mechanism by which ISG65 interferes with complement activation remains unknown. In this study, we show that ISG65 does not interfere directly with the assembly or activity of the two C3 convertases. However, ISG65 acts as a potent inhibitor of C3 deposition through the alternative pathway in human and murine serum. Degradation assays demonstrate that ISG65 stimulates the C3b to iC3b converting activity of complement factor I in the presence of the cofactors factor H or complement receptor 1. A structure-based model suggests that ISG65 promotes a C3b conformation susceptible to degradation or directly bridges factor I and C3b without contact with the cofactor. In addition, ISG65 is observed to form a stable ternary complex with the ligand binding domain of complement receptor 3 and iC3b. Our data suggest that ISG65 supports trypanosome complement evasion by accelerating the conversion of C3b to iC3b through a unique mechanism.
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Affiliation(s)
- Josefine Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Heidi G Olesen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | | | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Svend Birkelund
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | | | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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14
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Zhou L, Wu X, Qin S, Shi J, Yu C, Xu Z, Tian G, Zhu W, Qin J. Cell-liposome delivery system based on neuroinflammation to target the amygdala for ameliorating depressive-like behaviors. Int J Pharm 2023; 637:122724. [PMID: 36958607 DOI: 10.1016/j.ijpharm.2023.122724] [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: 09/13/2022] [Revised: 01/29/2023] [Accepted: 02/10/2023] [Indexed: 03/25/2023]
Abstract
Depression is a serious psychiatric disorder with unsatisfactory outcomes due to difficulties in delivering therapeutic molecules from the periphery to the brain. Neuroinflammation plays a key role in neurobiology and the treatment of depression. Neutrophils can cross the blood-brain barrier (BBB) and infiltrate key brain regions related to the pathophysiology of depression during neuroinflammation. N-Acetyl Pro-Gly-Pro (PGP) peptides efficiently bind to CXCR2 receptors on the surface of neutrophils. The neuropeptide oxytocin demonstrated antidepressant properties in preclinical and clinical studies, but its inability to penetrate the BBB hampers its therapeutic applications. In this study, we established a novel drug delivery system based on neutrophil infiltration in key brain regions during neuroinflammation. PGP was used to modify oxytocin-loaded liposomes (PGP-OTL) as the target ligand. Systematic administration of PGP-OTL exhibited enhanced antidepressant properties resulting from elevated oxytocin concentrations, especially in the amygdala, a crucial depression-implicated brain region. Enhanced antidepressant effects of PGP-OTL, similar to the ones caused by central oxytocin infusion, were observed in behavioral measurement including forced swim and tail suspension tests. Our study demonstrated that PGP-OTL can "hitchhike" neutrophils and enhance delivery of therapeutics into the brain, thus providing the means for developing novel cell-liposome-based drug delivery strategies for depression therapy.
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Affiliation(s)
- Liping Zhou
- Department of Pharmaceutics, School of Pharmacy, Fudan University & Key Laboratory of Smart Drug Delivery, Ministry of Education, Shanghai 201203, China
| | - Xiao Wu
- National Institute on Drug Dependence & Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Sijie Qin
- Department of Pharmaceutics, School of Pharmacy, Fudan University & Key Laboratory of Smart Drug Delivery, Ministry of Education, Shanghai 201203, China
| | - Jing Shi
- Department of Pharmaceutics, School of Pharmacy, Fudan University & Key Laboratory of Smart Drug Delivery, Ministry of Education, Shanghai 201203, China
| | - Chunfeng Yu
- Department of Pharmaceutics, School of Pharmacy, Heilongjiang University of Chinese Medicine
| | - Zhaowei Xu
- Precision Medicine Research Center, School of Pharmacy, Binzhou Medical University, Yantai, Shandong Province 264003, China
| | - Geng Tian
- Precision Medicine Research Center, School of Pharmacy, Binzhou Medical University, Yantai, Shandong Province 264003, China.
| | - Weili Zhu
- National Institute on Drug Dependence & Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China.
| | - Jing Qin
- Department of Pharmaceutics, School of Pharmacy, Fudan University & Key Laboratory of Smart Drug Delivery, Ministry of Education, Shanghai 201203, China.
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15
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Tvaroška I, Kozmon S, Kóňa J. Molecular Modeling Insights into the Structure and Behavior of Integrins: A Review. Cells 2023; 12:cells12020324. [PMID: 36672259 PMCID: PMC9856412 DOI: 10.3390/cells12020324] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Integrins are heterodimeric glycoproteins crucial to the physiology and pathology of many biological functions. As adhesion molecules, they mediate immune cell trafficking, migration, and immunological synapse formation during inflammation and cancer. The recognition of the vital roles of integrins in various diseases revealed their therapeutic potential. Despite the great effort in the last thirty years, up to now, only seven integrin-based drugs have entered the market. Recent progress in deciphering integrin functions, signaling, and interactions with ligands, along with advancement in rational drug design strategies, provide an opportunity to exploit their therapeutic potential and discover novel agents. This review will discuss the molecular modeling methods used in determining integrins' dynamic properties and in providing information toward understanding their properties and function at the atomic level. Then, we will survey the relevant contributions and the current understanding of integrin structure, activation, the binding of essential ligands, and the role of molecular modeling methods in the rational design of antagonists. We will emphasize the role played by molecular modeling methods in progress in these areas and the designing of integrin antagonists.
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Affiliation(s)
- Igor Tvaroška
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravska cesta 9, 845 38 Bratislava, Slovakia
- Correspondence:
| | - Stanislav Kozmon
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravska cesta 9, 845 38 Bratislava, Slovakia
- Medical Vision o. z., Záhradnícka 4837/55, 821 08 Bratislava, Slovakia
| | - Juraj Kóňa
- Institute of Chemistry, Slovak Academy of Sciences, Dúbravska cesta 9, 845 38 Bratislava, Slovakia
- Medical Vision o. z., Záhradnícka 4837/55, 821 08 Bratislava, Slovakia
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16
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Boero E, Gorham RD, Francis EA, Brand J, Teng LH, Doorduijn DJ, Ruyken M, Muts RM, Lehmann C, Verschoor A, van Kessel KPM, Heinrich V, Rooijakkers SHM. Purified complement C3b triggers phagocytosis and activation of human neutrophils via complement receptor 1. Sci Rep 2023; 13:274. [PMID: 36609665 PMCID: PMC9822988 DOI: 10.1038/s41598-022-27279-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/29/2022] [Indexed: 01/07/2023] Open
Abstract
The complement system provides vital immune protection against infectious agents by labeling them with complement fragments that enhance phagocytosis by immune cells. Many details of complement-mediated phagocytosis remain elusive, partly because it is difficult to study the role of individual complement proteins on target surfaces. Here, we employ serum-free methods to couple purified complement C3b onto E. coli bacteria and beads and then expose human neutrophils to these C3b-coated targets. We examine the neutrophil response using a combination of flow cytometry, confocal microscopy, luminometry, single-live-cell/single-target manipulation, and dynamic analysis of neutrophil spreading on opsonin-coated surfaces. We show that purified C3b can potently trigger phagocytosis and killing of bacterial cells via Complement receptor 1. Comparison of neutrophil phagocytosis of C3b- versus antibody-coated beads with single-bead/single-target analysis exposes a similar cell morphology during engulfment. However, bulk phagocytosis assays of C3b-beads combined with DNA-based quenching reveal that these are poorly internalized compared to their IgG1 counterparts. Similarly, neutrophils spread slower on C3b-coated compared to IgG-coated surfaces. These observations support the requirement of multiple stimulations for efficient C3b-mediated uptake. Together, our results establish the existence of a direct pathway of phagocytic uptake of C3b-coated targets and present methodologies to study this process.
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Affiliation(s)
- Elena Boero
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands ,grid.425088.3GSK, 53100 Siena, Italy
| | - Ronald D. Gorham
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands ,grid.417555.70000 0000 8814 392XSanofi, Waltham, MA 02451 USA
| | - Emmet A. Francis
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Jonathan Brand
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Lay Heng Teng
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Dennis J. Doorduijn
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Maartje Ruyken
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Remy M. Muts
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Christian Lehmann
- grid.5330.50000 0001 2107 3311Laboratory of Dendritic Cell Biology, Department of Dermatology, University Hospital of Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91052 Erlangen, Germany
| | - Admar Verschoor
- grid.15474.330000 0004 0477 2438Department of Otorhinolaryngology, Technische Universität München and Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Kok P. M. van Kessel
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Volkmar Heinrich
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Suzan H. M. Rooijakkers
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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17
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Carroll JB, Hamidi S, Gabriele ML. Microglial heterogeneity and complement component 3 elimination within emerging multisensory midbrain compartments during an early critical period. Front Neurosci 2023; 16:1072667. [PMID: 36685243 PMCID: PMC9846048 DOI: 10.3389/fnins.2022.1072667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/09/2022] [Indexed: 01/05/2023] Open
Abstract
The lateral cortex of the inferior colliculus (LCIC) is a midbrain shell region that receives multimodal inputs that target discrete zones of its compartmental (modular-matrix) framework. This arrangement emerges perinatally in mice (postnatal day, P0-P12) as somatosensory and auditory inputs segregate into their respective modular and matrix terminal patterns. Microglial cells (MGCs) perform a variety of critical functions in the developing brain, among them identifying areas of active circuit assembly and selectively pruning exuberant or underutilized connections. Recent evidence in other brain structures suggest considerable MGC heterogeneity across the lifespan, particularly during established developmental critical periods. The present study examines the potential involvement of classical complement cascade signaling (C3-CR3/CD11b) in refining early multisensory networks, and identifies several microglial subsets exhibiting distinct molecular signatures within the nascent LCIC. Immunostaining was performed in GAD67-green fluorescent protein (GFP) and CX3CR1-GFP mice throughout and after the defined LCIC critical period. GAD labeling highlights the emerging LCIC modularity, while CX3CR1 labeling depicts MGCs expressing the fractalkine receptor. C3 expression is widespread throughout the LCIC neuropil early on, prior to its conspicuous absence from modular zones at P8, and more global disappearance following critical period closure. CD11b-expressing microglia while homogeneously distributed at birth, are biased to modular fields at P8 and then the surrounding matrix by P12. Temporal and spatial matching of the disappearance of C3 by LCIC compartment (i.e., modules then matrix) with CD11b-positive MGC occupancy implicates complement signaling in the selective refinement of early LCIC connectivity. Multiple-labeling studies for a variety of established MGC markers (CD11b, CX3CR1, Iba1, TMEM119) indicate significant MGC heterogeneity in the LCIC as its compartments and segregated multisensory maps emerge. Marker colocalization was the exception rather than the rule, suggesting that unique MGC subpopulations exist in the LCIC and perhaps serve distinct developmental roles. Potential mechanisms whereby microglia sculpt early multisensory LCIC maps and how such activity/inactivity may underlie certain neurodevelopmental conditions, including autism spectrum disorder and schizophrenia, are discussed.
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Affiliation(s)
| | | | - Mark L. Gabriele
- Department of Biology, James Madison University, Harrisonburg, VA, United States
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18
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Schmidt CQ, Smith RJH. Protein therapeutics and their lessons: Expect the unexpected when inhibiting the multi-protein cascade of the complement system. Immunol Rev 2023; 313:376-401. [PMID: 36398537 PMCID: PMC9852015 DOI: 10.1111/imr.13164] [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] [Indexed: 11/19/2022]
Abstract
Over a century after the discovery of the complement system, the first complement therapeutic was approved for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). It was a long-acting monoclonal antibody (aka 5G1-1, 5G1.1, h5G1.1, and now known as eculizumab) that targets C5, specifically preventing the generation of C5a, a potent anaphylatoxin, and C5b, the first step in the eventual formation of membrane attack complex. The enormous clinical and financial success of eculizumab across four diseases (PNH, atypical hemolytic uremic syndrome (aHUS), myasthenia gravis (MG), and anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD)) has fueled a surge in complement therapeutics, especially targeting diseases with an underlying complement pathophysiology for which anti-C5 therapy is ineffective. Intensive research has also uncovered challenges that arise from C5 blockade. For example, PNH patients can still face extravascular hemolysis or pharmacodynamic breakthrough of complement suppression during complement-amplifying conditions. These "side" effects of a stoichiometric inhibitor like eculizumab were unexpected and are incompatible with some of our accepted knowledge of the complement cascade. And they are not unique to C5 inhibition. Indeed, "exceptions" to the rules of complement biology abound and have led to unprecedented and surprising insights. In this review, we will describe initial, present and future aspects of protein inhibitors of the complement cascade, highlighting unexpected findings that are redefining some of the mechanistic foundations upon which the complement cascade is organized.
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Affiliation(s)
- Christoph Q. Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Richard J. H. Smith
- Departments of Internal Medicine and Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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19
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Nguyen H, Jing T, Wang X. The Q163C/Q309C mutant of αMI-domain is an active variant suitable for NMR characterization. PLoS One 2023; 18:e0280778. [PMID: 36696377 PMCID: PMC9876370 DOI: 10.1371/journal.pone.0280778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
Integrin αMβ2 (Mac-1, CD11b/CD18, CR3) is an important adhesion receptor expressed on monocytes. Mac-1 is responsible for mediating cell migration, phagocytosis, degranulation as well as cell-cell fusion. It is also the most promiscuous integrin in terms of ligand specificity with over 100 ligands, most of which use the αMI-domain as their binding site. Despite the importance of αMI-domain in defining ligand interactions of Mac-1, structural studies of αMI-domain's interactions with ligands are lacking. In particular, solution NMR studies of αMI-domain's interaction with ligands have not been possible because the most commonly used active αMI-domain mutants (I316G and ΔK315) are not sufficiently stable and soluble to be used in solution NMR. The goal of this study is to identify an αMI-domain active mutant that's amenable to NMR characterization. By screening known activating mutations of αMI-domain, we determined that the Q163C/Q309C mutant, which converts the αMI-domain into its active form through the formation of an intramolecular disulfide bond, can be produced with a high yield and is more stable than other active mutants. In addition, the Q163C/Q309C mutant has better NMR spectral quality than other active mutants and its affinity for ligands is comparable to other active mutants. Analysis of the Co2+-induced pseudocontact shifts in the Q163C/Q309C mutant showed the structure of the mutant is consistent with the active conformation. Finally, we show that the minor fraction of the Q163C/Q309C mutant without the disulfide bond can be removed through the use of carboxymethyl sepharose chromatography. We think the availability of this mutant for NMR study will significantly enhance structural characterizations of αMI-domain-ligand interactions.
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Affiliation(s)
- Hoa Nguyen
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Tianwei Jing
- Biosensing Instrument Inc., Tempe, Arizona, United States of America
| | - Xu Wang
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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20
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Abbasi A, Rahbar Saadat T, Rahbar Saadat Y. Microbial exopolysaccharides-β-glucans-as promising postbiotic candidates in vaccine adjuvants. Int J Biol Macromol 2022; 223:346-361. [PMID: 36347372 DOI: 10.1016/j.ijbiomac.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/29/2022] [Accepted: 11/01/2022] [Indexed: 11/08/2022]
Abstract
The urgent task of creating new, enhanced adjuvants is closely related to our comprehension of their mechanisms of action. A few adjuvants have shown sufficient efficacy and low toxicity to be allowed for use in human vaccines, despite the fact that they have a long history and an important function. Adjuvants have long been used without a clear understanding of how precisely they augment the immune response. The rational production of stronger and safer adjuvants has been impeded by this lack of information, which necessitates more mechanistic research to support the development of vaccines. Carbohydrate structures-polygalactans, fructans, β-D-glucans, α-D-glucans, D-galactose, and D-glucose-are desirable candidates for the creation of vaccine adjuvants and immunomodulators because they serve important functions in nature and are often biocompatible, safe, and well tolerated. In this review, we have discussed recent advances in microbial-derived carbohydrate-based adjuvants, their immunostimulatory activity, and the implications of this for vaccine development, along with the critical view on the microbial sources, chemical composition, and biosynthetic pathways.
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Affiliation(s)
- Amin Abbasi
- Department of Food Science and Technology, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Yalda Rahbar Saadat
- Kidney Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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21
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Saez-Calveras N, Brewster AL, Stuve O. The validity of animal models to explore the pathogenic role of the complement system in multiple sclerosis: A review. Front Mol Neurosci 2022; 15:1017484. [PMID: 36311030 PMCID: PMC9606595 DOI: 10.3389/fnmol.2022.1017484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 09/26/2022] [Indexed: 11/26/2022] Open
Abstract
Animal models of multiple sclerosis (MS) have been extensively used to characterize the disease mechanisms in MS, as well as to identify potential pharmacologic targets for this condition. In recent years, the immune complement system has gained increased attention as an important effector in the pathogenesis of MS. Evidence from histological, serum, and CSF studies of patients supports an involvement of complement in both relapsing-remitting and progressive MS. In this review, we discuss the history and advances made on the use of MS animal models to profile the effects of the complement system in this condition. The first studies that explored the complement system in the context of MS used cobra venom factor (CVF) as a complement depleting agent in experimental autoimmune encephalomyelitis (EAE) Lewis rats. Since then, multiple mice and rat models of MS have revealed a role of C3 and the alternative complement cascade in the opsonization and phagocytosis of myelin by microglia and myeloid cells. Studies using viral vectors, genetic knockouts and pharmacologic complement inhibitors have also shown an effect of complement in synaptic loss. Antibody-mediated EAE models have revealed an involvement of the C1 complex and the classical complement as an effector of the humoral response in this disease. C1q itself may also be involved in modulating microglia activation and oligodendrocyte differentiation in these animals. In addition, animal and in vitro models have revealed that multiple complement factors may act as modulators of both the innate and adaptive immune responses. Finally, evidence gathered from mice models suggests that the membrane attack complex (MAC) may even exert protective roles in the chronic stages of EAE. Overall, this review summarizes the importance of MS animal models to better characterize the role of the complement system and guide future therapeutic approaches in this condition.
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Affiliation(s)
- Nil Saez-Calveras
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Neurology Section, Parkland Hospital, Dallas, TX, United States
| | - Amy L. Brewster
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, United States
| | - Olaf Stuve
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Neurology Section, VA North Texas Health Care System, Dallas, TX, United States
- Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
- *Correspondence: Olaf Stuve,
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22
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Lorentzen J, Pedersen DV, Gadeberg TAF, Andersen GR. Structure determination of an unstable macromolecular complex enabled by nanobody-peptide bridging. Protein Sci 2022; 31:e4432. [PMID: 36173177 PMCID: PMC9601772 DOI: 10.1002/pro.4432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/24/2022] [Indexed: 11/23/2022]
Abstract
Structure determination of macromolecular complexes is challenging if subunits can dissociate during crystallization or preparation of electron microscopy grids. We present an approach where a labile complex is stabilized by linking subunits though introduction of a peptide tag in one subunit that is recognized by a nanobody tethered to a second subunit. This allowed crystal structure determination at 3.9 Å resolution of the highly non‐globular 320 kDa proconvertase formed by complement components C3b, factor B, and properdin. Whereas the binding mode of properdin to C3b is preserved, an internal rearrangement occurs in the zymogen factor B von Willebrand domain type A domain compared to the proconvertase not bound to properdin. The structure emphasizes the role of two noncanonical loops in thrombospondin repeats 5 and 6 of properdin in augmenting the activity of the C3 convertase. We suggest that linking of subunits through peptide specific tethered nanobodies represents a simple alternative to approaches like affinity maturation and chemical cross‐linking for the stabilization of large macromolecular complexes. Besides applications for structural biology, nanobody bridging may become a new tool for biochemical analysis of unstable macromolecular complexes and in vitro selection of highly specific binders for such complexes. PDB Code(s): 7NOZ;
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Affiliation(s)
- Josefine Lorentzen
- Department of Molecular Biology and Genetics, Section for Protein ScienceAarhus UniversitetAarhusDenmark
| | | | - Trine Amalie Fogh Gadeberg
- Department of Molecular Biology and Genetics, Section for Protein ScienceAarhus UniversitetAarhusDenmark
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Section for Protein ScienceAarhus UniversitetAarhusDenmark
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23
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Heterotropic roles of divalent cations in the establishment of allostery and affinity maturation of integrin αXβ2. Cell Rep 2022; 40:111254. [PMID: 36001965 PMCID: PMC9440770 DOI: 10.1016/j.celrep.2022.111254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 05/23/2022] [Accepted: 08/02/2022] [Indexed: 11/21/2022] Open
Abstract
Allosteric activation and silencing of leukocyte β2-integrins transpire through cation-dependent structural changes, which mediate integrin biosynthesis and recycling, and are essential to designing leukocyte-specific drugs. Stepwise addition of Mg2+ reveals two mutually coupled events for the αXβ2 ligand-binding domain-the αX I-domain-corresponding to allostery establishment and affinity maturation. Electrostatic alterations in the Mg2+-binding site establish long-range couplings, leading to both pH- and Mg2+-occupancy-dependent biphasic stability change in the αX I-domain fold. The ligand-binding sensorgrams show composite affinity events for the αX I-domain accounting for the multiplicity of the αX I-domain conformational states existing in the solution. On cell surfaces, increasing Mg2+ concentration enhanced adhesiveness of αXβ2. This work highlights how intrinsically flexible pH- and cation-sensitive architecture endows a unique dynamic continuum to the αI-domain structure on the intact integrin, thereby revealing the importance of allostery establishment and affinity maturation in both extracellular and intracellular integrin events.
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24
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Schanzenbacher J, Köhl J, Karsten CM. Anaphylatoxins spark the flame in early autoimmunity. Front Immunol 2022; 13:958392. [PMID: 35958588 PMCID: PMC9358992 DOI: 10.3389/fimmu.2022.958392] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
The complement system (CS) is an ancient and highly conserved part of the innate immune system with important functions in immune defense. The multiple fragments bind to specific receptors on innate and adaptive immune cells, the activation of which translates the initial humoral innate immune response (IR) into cellular innate and adaptive immunity. Dysregulation of the CS has been associated with the development of several autoimmune disorders such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ANCA-associated vasculitis, and autoimmune bullous dermatoses (AIBDs), where complement drives the inflammatory response in the effector phase. The role of the CS in autoimmunity is complex. On the one hand, complement deficiencies were identified as risk factors to develop autoimmune disorders. On the other hand, activation of complement can drive autoimmune responses. The anaphylatoxins C3a and C5a are potent mediators and regulators of inflammation during the effector phase of autoimmunity through engagement of specific anaphylatoxin receptors, i.e., C3aR, C5aR1, and C5aR2 either on or in immune cells. In addition to their role in innate IRs, anaphylatoxins regulate humoral and cellular adaptive IRs including B-cell and T-cell activation, differentiation, and survival. They regulate B- and T-lymphocyte responses either directly or indirectly through the activation of anaphylatoxin receptors via dendritic cells that modulate lymphocyte function. Here, we will briefly review our current understanding of the complex roles of anaphylatoxins in the regulation of immunologic tolerance and the early events driving autoimmunity and the implications of such regulation for therapeutic approaches that target the CS.
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Affiliation(s)
- Jovan Schanzenbacher
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Childrens Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
- *Correspondence: Christian M. Karsten,
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25
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Jensen RK, Pedersen H, Lorentzen J, Laursen NS, Vorup-Jensen T, Andersen GR. Structural insights into the function-modulating effects of nanobody binding to the integrin receptor α Mβ 2. J Biol Chem 2022; 298:102168. [PMID: 35738398 PMCID: PMC9287160 DOI: 10.1016/j.jbc.2022.102168] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 01/12/2023] Open
Abstract
The integrin receptor αMβ2 mediates phagocytosis of complement-opsonized objects, adhesion to the extracellular matrix, and transendothelial migration of leukocytes. However, the mechanistic aspects of αMβ2 signaling upon ligand binding are unclear. Here, we present the first atomic structure of the human αMβ2 headpiece fragment in complex with the nanobody (Nb) hCD11bNb1 at a resolution of 3.2 Å. We show that the receptor headpiece adopts the closed conformation expected to exhibit low ligand affinity. The crystal structure indicates that in the R77H αM variant, associated with systemic lupus erythematosus, the modified allosteric relationship between ligand binding and integrin outside–inside signaling is due to subtle conformational effects transmitted over a distance of 40 Å. Furthermore, we found the Nb binds to the αI domain of the αM subunit in an Mg2+-independent manner with low nanomolar affinity. Biochemical and biophysical experiments with purified proteins demonstrated that the Nb acts as a competitive inhibitor through steric hindrance exerted on the thioester domain of complement component iC3b attempting to bind the αM subunit. Surprisingly, we show that the Nb stimulates the interaction of cell-bound αMβ2 with iC3b, suggesting that it may represent a novel high-affinity proteinaceous αMβ2-specific agonist. Taken together, our data suggest that the iC3b–αMβ2 complex may be more dynamic than predicted from the crystal structure of the core complex. We propose a model based on the conformational spectrum of the receptor to reconcile these observations regarding the functional consequences of hCD11bNb1 binding to αMβ2.
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Affiliation(s)
- Rasmus K Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Henrik Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Josefine Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
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26
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Zauhar R, Biber J, Jabri Y, Kim M, Hu J, Kaplan L, Pfaller AM, Schäfer N, Enzmann V, Schlötzer-Schrehardt U, Straub T, Hauck SM, Gamlin PD, McFerrin MB, Messinger J, Strang CE, Curcio CA, Dana N, Pauly D, Grosche A, Li M, Stambolian D. As in Real Estate, Location Matters: Cellular Expression of Complement Varies Between Macular and Peripheral Regions of the Retina and Supporting Tissues. Front Immunol 2022; 13:895519. [PMID: 35784369 PMCID: PMC9240314 DOI: 10.3389/fimmu.2022.895519] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/11/2022] [Indexed: 01/02/2023] Open
Abstract
The cellular events that dictate the initiation of the complement pathway in ocular degeneration, such as age-related macular degeneration (AMD), is poorly understood. Using gene expression analysis (single cell and bulk), mass spectrometry, and immunohistochemistry, we dissected the role of multiple retinal and choroidal cell types in determining the complement homeostasis. Our scRNA-seq data show that the cellular response to early AMD is more robust in the choroid, particularly in fibroblasts, pericytes and endothelial cells. In late AMD, complement changes were more prominent in the retina especially with the expression of the classical pathway initiators. Notably, we found a spatial preference for these differences. Overall, this study provides insights into the heterogeneity of cellular responses for complement expression and the cooperation of neighboring cells to complete the pathway in healthy and AMD eyes. Further, our findings provide new cellular targets for therapies directed at complement.
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Affiliation(s)
- Randy Zauhar
- Department of Chemistry and Biochemistry, The University of the Sciences in Philadelphia, Philadelphia, PA, United States
| | - Josef Biber
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Yassin Jabri
- Department of Ophthalmology, University Hospital Regensburg, Regensburg, Germany
| | - Mijin Kim
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Jian Hu
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Lew Kaplan
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Anna M. Pfaller
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Nicole Schäfer
- Department of Ophthalmology, University Hospital Regensburg, Regensburg, Germany
- Department of Orthopaedic Surgery, Experimental Orthopaedics, Centre for Medical Biotechnology (ZMB), University of Regensburg, Regensburg, Germany
| | - Volker Enzmann
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | | | - Tobias Straub
- Bioinformatics Unit, Biomedical Center, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Stefanie M. Hauck
- Metabolomics and Proteomics Core and Research Unit Protein Science, Helmholtz-Zentrum München, Neuherberg, Germany
| | - Paul D. Gamlin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Michael B. McFerrin
- Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jeffrey Messinger
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christianne E. Strang
- Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Nicholas Dana
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Diana Pauly
- Department of Ophthalmology, University Hospital Regensburg, Regensburg, Germany
- Experimental Ophthalmology, University of Marburg, Marburg, Germany
| | - Antje Grosche
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Mingyao Li
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Dwight Stambolian
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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27
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The crystal structure of iC3b-CR3 αI reveals a modular recognition of the main opsonin iC3b by the CR3 integrin receptor. Nat Commun 2022; 13:1955. [PMID: 35413960 PMCID: PMC9005620 DOI: 10.1038/s41467-022-29580-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 03/15/2022] [Indexed: 12/27/2022] Open
Abstract
Complement activation on cell surfaces leads to the massive deposition of C3b, iC3b, and C3dg, the main complement opsonins. Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we present the crystallographic structure of the complex between human iC3b and the von Willebrand A inserted domain of the α chain of CR3 (αI). The crystal contains two composite interfaces for CR3 αI, encompassing distinct sets of contiguous macroglobulin (MG) domains on the C3c moiety, MG1-MG2 and MG6-MG7 domains. These composite binding sites define two iC3b-CR3 αI complexes characterized by specific rearrangements of the two semi-independent modules, C3c moiety and TED domain. Furthermore, we show the structure of iC3b in a physiologically-relevant extended conformation. Based on previously available data and novel insights reported herein, we propose an integrative model that reconciles conflicting facts about iC3b structure and function and explains the molecular basis for iC3b selective recognition by CR3 on opsonized surfaces. Complement activation on foreign cell surfaces leads to the generation of complement opsonins, which activate complement receptor type 3 (CR3) and pathogen clearance by macrophages. Here, the authors reveal structural basis of the interaction between human opsonin iC3b and the von Willebrand A inserted domain of the α chain of CR3.
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28
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Anliker M, Drees D, Loacker L, Hafner S, Griesmacher A, Hoermann G, Fux V, Schennach H, Hörtnagl P, Dopler A, Schmidt S, Bellmann-Weiler R, Weiss G, Marx-Hofmann A, Körper S, Höchsmann B, Schrezenmeier H, Schmidt CQ. Upregulation of Checkpoint Ligand Programmed Death-Ligand 1 in Patients with Paroxysmal Nocturnal Hemoglobinuria Explained by Proximal Complement Activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:1248-1258. [PMID: 35173033 DOI: 10.4049/jimmunol.2100031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 12/17/2021] [Indexed: 12/12/2022]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hemolytic disease driven by impaired complement regulation. Mutations in genes encoding the enzymes that build the GPI anchors are causative, with somatic mutations in the PIG-A gene occurring most frequently. As a result, the important membrane-bound complement regulators CD55 and CD59 are missing on the affected hematopoietic stem cells and their progeny, rendering those cells vulnerable to complement attack. Immune escape mechanisms sparing affected PNH stem cells from removal are suspected in the PNH pathogenesis, but molecular mechanisms have not been elucidated. We hypothesized that exuberant complement activity in PNH results in enhanced immune checkpoint interactions, providing a molecular basis for the potential immune escape in PNH. In a series of PNH patients, we found increased expression levels of the checkpoint ligand programmed death-ligand 1 (PD-L1) on granulocytes and monocytes, as well as in the plasma of PNH patients. Mechanistically, we demonstrate that complement activation leading to the decoration of particles/cells with C3- and/or C4-opsonins increased PD-L1 expression on neutrophils and monocytes as shown for different in vitro models of classical or alternative pathway activation. We further establish in vitro that complement inhibition at the level of C3, but not C5, inhibits the alternative pathway-mediated upregulation of PD-L1 and show by means of soluble PD-L1 that this observation translates into the clinical situation when PNH patients are treated with either C3 or C5 inhibitors. Together, the presented data show that the checkpoint ligand PD-L1 is increased in PNH patients, which correlates with proximal complement activation.
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Affiliation(s)
- Markus Anliker
- Central Institute for Medical and Chemical Laboratory Diagnosis, University Hospital, Innsbruck, Austria
| | - Daniela Drees
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Lorin Loacker
- Central Institute for Medical and Chemical Laboratory Diagnosis, University Hospital, Innsbruck, Austria
| | - Susanne Hafner
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Andrea Griesmacher
- Central Institute for Medical and Chemical Laboratory Diagnosis, University Hospital, Innsbruck, Austria
| | - Gregor Hoermann
- Central Institute for Medical and Chemical Laboratory Diagnosis, University Hospital, Innsbruck, Austria.,MLL Munich Leukemia Laboratory, Munich, Germany
| | - Vilmos Fux
- Central Institute for Medical and Chemical Laboratory Diagnosis, University Hospital, Innsbruck, Austria
| | - Harald Schennach
- Central Institute of Blood Transfusion and Immunology, University Hospital Innsbruck, Innsbruck, Austria
| | - Paul Hörtnagl
- Central Institute of Blood Transfusion and Immunology, University Hospital Innsbruck, Innsbruck, Austria
| | - Arthur Dopler
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Stefan Schmidt
- Department of Internal Medicine V, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Rosa Bellmann-Weiler
- Department of Internal Medicine II, Innsbruck Medical University, Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Innsbruck Medical University, Innsbruck, Austria
| | - Astrid Marx-Hofmann
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Sixten Körper
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Britta Höchsmann
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Hubert Schrezenmeier
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany; .,Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden-Württemberg-Hessen and University Hospital of Ulm, Ulm, Germany
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany;
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29
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Ponnusamy N, Arumugam M. Interaction of Host Pattern Recognition Receptors (PRRs) with Mycobacterium Tuberculosis and Ayurvedic Management of Tuberculosis: A Systemic Approach. Infect Disord Drug Targets 2022; 22:e130921196420. [PMID: 34517809 DOI: 10.2174/1871526521666210913110834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/15/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), infects the lungs' alveolar surfaces through aerosol droplets. At this stage, the disease progression may have many consequences, determined primarily by the reactions of the human immune system. However, one approach will be to more actively integrate the immune system, especially the pattern recognition receptor (PRR) systems of the host, which notices pathogen-associated molecular patterns (PAMPs) of Mtb. Several types of PRRs are involved in the detection of Mtb, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), Dendritic cell (DC) -specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), Mannose receptor (MR), and NOD-like receptors (NLRs) related to inflammasome activation. In this study, we focus on reviewing the Mtb pathophysiology and interaction of host PPRs with Mtb as well as adverse drug effects of anti-tuberculosis drugs (ATDs) and systematic TB treatment via Ayurvedic medicine.
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Affiliation(s)
- Nirmaladevi Ponnusamy
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
| | - Mohanapriya Arumugam
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
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30
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Complement component C3: A structural perspective and potential therapeutic implications. Semin Immunol 2022; 59:101627. [PMID: 35760703 PMCID: PMC9842190 DOI: 10.1016/j.smim.2022.101627] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/03/2022] [Accepted: 06/09/2022] [Indexed: 01/18/2023]
Abstract
As the most abundant component of the complement system, C3 and its proteolytic derivatives serve essential roles in the function of all three complement pathways. Central to this is a network of protein-protein interactions made possible by the sequential proteolysis and far-reaching structural changes that accompany C3 activation. Beginning with the crystal structures of C3, C3b, and C3c nearly twenty years ago, the physical transformations underlying C3 function that had long been suspected were finally revealed. In the years that followed, a compendium of crystallographic information on C3 derivatives bound to various enzymes, regulators, receptors, and inhibitors generated new levels of insight into the structure and function of the C3 molecule. This Review provides a concise classification, summary, and interpretation of the more than 50 unique crystal structure determinations for human C3. It also highlights other salient features of C3 structure that were made possible through solution-based methods, including Hydrogen/Deuterium Exchange and Small Angle X-ray Scattering. At this pivotal time when the first C3-targeted therapeutics begin to see use in the clinic, some perspectives are also offered on how this continually growing body of structural information might be leveraged for future development of next-generation C3 inhibitors.
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31
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Raballah E, Anyona SB, Cheng Q, Munde EO, Hurwitz IF, Onyango C, Ndege C, Hengartner NW, Pacheco MA, Escalante AA, Lambert CG, Ouma C, Obama HCJT, Scheider KA, Seidenberg PD, McMahon BH, Perkins DJ. Complement component 3 mutations alter the longitudinal risk of pediatric malaria and severe malarial anemia. Exp Biol Med (Maywood) 2021; 247:672-682. [PMID: 34842470 DOI: 10.1177/15353702211056272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Severe malarial anemia (SMA) is a leading cause of childhood morbidity and mortality in holoendemic Plasmodium falciparum transmission regions. To gain enhanced understanding of predisposing factors for SMA, we explored the relationship between complement component 3 (C3) missense mutations [rs2230199 (2307C>G, Arg>Gly102) and rs11569534 (34420G>A, Gly>Asp1224)], malaria, and SMA in a cohort of children (n = 1617 children) over 36 months of follow-up. Variants were selected based on their ability to impart amino acid substitutions that can alter the structure and function of C3. The 2307C>G mutation results in a basic to a polar residue change (Arg to Gly) at position 102 (β-chain) in the macroglobulin-1 (MG1) domain, while 34420G>A elicits a polar to acidic residue change (Gly to Asp) at position 1224 (α-chain) in the thioester-containing domain. After adjusting for multiple comparisons, longitudinal analyses revealed that inheritance of the homozygous mutant (GG) at 2307 enhanced the risk of SMA (RR = 2.142, 95%CI: 1.229-3.735, P = 0.007). The haplotype containing both wild-type alleles (CG) decreased the incident risk ratio of both malaria (RR = 0.897, 95%CI: 0.828-0.972, P = 0.008) and SMA (RR = 0.617, 95%CI: 0.448-0.848, P = 0.003). Malaria incident risk ratio was also reduced in carriers of the GG (Gly102Gly1224) haplotype (RR = 0.941, 95%CI: 0.888-0.997, P = 0.040). Collectively, inheritance of the missense mutations in MG1 and thioester-containing domain influence the longitudinal risk of malaria and SMA in children exposed to intense Plasmodium falciparum transmission.
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Affiliation(s)
- Evans Raballah
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya.,Department of Medical Laboratory Sciences, 118970School of Public Health Biomedical Sciences and Technology, Masinde Muliro University of Science and Technology, 50100 Kakamega, Kenya
| | - Samuel B Anyona
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya.,Department of Medical Biochemistry, 118971School of Medicine, Maseno University, 40105 Maseno, Kenya
| | - Qiuying Cheng
- Center for Global Health, Department of Internal Medicine, 1104University of New Mexico, Albuquerque, 87131 NM, USA
| | - Elly O Munde
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya.,Department of Clinical Medicine, Kirinyaga University School of Health Sciences, Kerugoya 10300, Kenya
| | - Ivy-Foo Hurwitz
- Center for Global Health, Department of Internal Medicine, 1104University of New Mexico, Albuquerque, 87131 NM, USA
| | - Clinton Onyango
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya
| | - Caroline Ndege
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya
| | - Nicolas W Hengartner
- Theoretical Division, Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, 87544 NM, USA
| | - Maria Andreína Pacheco
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA 19122, USA
| | - Ananias A Escalante
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA 19122, USA
| | - Christophe G Lambert
- Center for Global Health, Department of Internal Medicine, 1104University of New Mexico, Albuquerque, 87131 NM, USA
| | - Collins Ouma
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya.,Department of Biomedical Sciences and Technology, 118971School of Public Health and Community Development, Maseno University, 40105 Maseno, Kenya
| | - Henri C Jr T Obama
- Department of Applied Computer and Biosciences, University of Applied Sciences Mittweida, Technikumplatz, Mittweida 09648, Germany
| | - Kristan A Scheider
- Department of Applied Computer and Biosciences, University of Applied Sciences Mittweida, Technikumplatz, Mittweida 09648, Germany
| | - Philip D Seidenberg
- Department of Emergency Medicine, 1104University of New Mexico, Albuquerque, NM 87131, USA
| | - Benjamin H McMahon
- Theoretical Division, Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, 87544 NM, USA
| | - Douglas J Perkins
- 1104University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya 40100, Kenya.,Center for Global Health, Department of Internal Medicine, 1104University of New Mexico, Albuquerque, 87131 NM, USA
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32
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Jin L, Han X, Zhang X, Zhao Z, Ulrich J, Syrovets T, Simmet T. Identification of Oleanolic Acid as Allosteric Agonist of Integrin α M by Combination of In Silico Modeling and In Vitro Analysis. Front Pharmacol 2021; 12:702529. [PMID: 34603018 PMCID: PMC8484648 DOI: 10.3389/fphar.2021.702529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/31/2021] [Indexed: 12/31/2022] Open
Abstract
Oleanolic acid is a widely distributed natural product, which possesses promising antitumor, antiviral, antihyperlipidemic, and anti-inflammatory activities. A heterodimeric complex formed by integrin αM (CD11b) and integrin β2 (CD18) is highly expressed on monocytes and macrophages. In the current study, we demonstrate that the I domain of αM (αM-I domain) might present a potential cellular target for oleanolic acid. In vitro data show that oleanolic acid induces clustering of αM on macrophages and reduces their non-directional migration. In accordance with experimental data, molecular docking revealed that oleanolic acid binds to the αM-I domain in its extended-open form, the dominant conformation found in αM clusters. Molecular dynamics simulation revealed that oleanolic acid can increase the flexibility of the α7 helix and promote its movement away from the N-terminus, indicating that oleanolic acid may facilitate the conversion of the αM-I domain from the extended-closed to the extended-open conformation. As demonstrated by metadynamics simulation, oleanolic acid can destabilize the local minimum of the αM-I domain in the open conformation partially through disturbance of the interactions between α1 and α7 helices. In summary, we demonstrate that oleanolic acid might function as an allosteric agonist inducing clustering of αM on macrophages by shifting the balance from the closed to the extended-open conformation. The molecular target identified in this study might hold potential for a purposeful use of oleanolic acid to modulate chronic inflammatory responses.
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Affiliation(s)
- Lu Jin
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany.,School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Xiaoyu Han
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Xinlei Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Zhimin Zhao
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Judith Ulrich
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Tatiana Syrovets
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Thomas Simmet
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
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33
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Characterization of DNA-protein complexes by nanoparticle tracking analysis and their association with systemic lupus erythematosus. Proc Natl Acad Sci U S A 2021; 118:2106647118. [PMID: 34301873 DOI: 10.1073/pnas.2106647118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nanotechnology enables investigations of single biomacromolecules, but technical challenges have limited the application in liquid biopsies, for example, blood plasma. Nonetheless, tools to characterize single molecular species in such samples represent a significant unmet need with the increasing appreciation of the physiological importance of protein structural changes at nanometer scale. Mannose-binding lectin (MBL) is an oligomeric plasma protein and part of the innate immune system through its ability to activate complement. MBL also serves a role as a scavenger for cellular debris, especially DNA. This may link functions of MBL with several inflammatory diseases in which cell-free DNA now appears to play a role, but mechanistic insight has been lacking. By making nanoparticle tracking analysis possible in human plasma, we now show that superoligomeric structures of MBL form nanoparticles with DNA. These oligomers correlate with disease activity in systemic lupus erythematosus patients. With the direct quantification of the hydrodynamic radius, calculations following the principles of Taylor dispersion in the blood stream connect the size of these complexes to endothelial inflammation, which is among the most important morbidities in lupus. Mechanistic insight from an animal model of lupus supported that DNA-stabilized superoligomers stimulate the formation of germinal center B cells and drive loss of immunological tolerance. The formation involves an inverse relationship between the concentration of MBL superoligomers and antibodies to double-stranded DNA. Our approach implicates the structure of DNA-protein nanoparticulates in the pathobiology of autoimmune diseases.
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Kim BJ, Mastellos DC, Li Y, Dunaief JL, Lambris JD. Targeting complement components C3 and C5 for the retina: Key concepts and lingering questions. Prog Retin Eye Res 2021; 83:100936. [PMID: 33321207 PMCID: PMC8197769 DOI: 10.1016/j.preteyeres.2020.100936] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/13/2022]
Abstract
Age-related macular degeneration (AMD) remains a major cause of legal blindness, and treatment for the geographic atrophy form of AMD is a significant unmet need. Dysregulation of the complement cascade is thought to be instrumental for AMD pathophysiology. In particular, C3 and C5 are pivotal components of the complement cascade and have become leading therapeutic targets for AMD. In this article, we discuss C3 and C5 in detail, including their roles in AMD, biochemical and structural aspects, locations of expression, and the functions of C3 and C5 fragments. Further, the article critically reviews developing therapeutics aimed at C3 and C5, underscoring the potential effects of broad inhibition of complement at the level of C3 versus more specific inhibition at C5. The relationships of complement biology to the inflammasome and microglia/macrophage activity are highlighted. Concepts of C3 and C5 biology will be emphasized, while we point out questions that need to be settled and directions for future investigations.
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Affiliation(s)
- Benjamin J Kim
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | | | - Yafeng Li
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joshua L Dunaief
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John D Lambris
- Department of Laboratory Medicine and Pathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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35
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Jensen RK, Bajic G, Sen M, Springer TA, Vorup-Jensen T, Andersen GR. Complement Receptor 3 Forms a Compact High-Affinity Complex with iC3b. THE JOURNAL OF IMMUNOLOGY 2021; 206:3032-3042. [PMID: 34117107 DOI: 10.4049/jimmunol.2001208] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Abstract
Complement receptor 3 (CR3, also known as Mac-1, integrin αMβ2, or CD11b/CD18) is expressed on a subset of myeloid and certain activated lymphoid cells. CR3 is essential for the phagocytosis of complement-opsonized particles such as pathogens and apoptotic or necrotic cells opsonized with the complement fragment iC3b and, to a lesser extent, C3dg. Although the interaction between the iC3b thioester domain and the ligand binding CR3 αM I-domain is structurally and functionally well characterized, the nature of additional CR3-iC3b interactions required for phagocytosis of complement-opsonized objects remains obscure. In this study, we analyzed the interaction between iC3b and the 150-kDa headpiece fragment of the CR3 ectodomain. Surface plasmon resonance experiments demonstrated a 30 nM affinity of the CR3 headpiece for iC3b compared with 515 nM for the iC3b thioester domain, whereas experiments monitoring binding of iC3b to CR3-expressing cells suggested an affinity of 50 nM for the CR3-iC3b interaction. Small angle x-ray scattering analysis revealed that iC3b adopts an extended but preferred conformation in solution. Upon interaction with CR3, iC3b rearranges to form a compact receptor-ligand complex. Overall, the data suggest that the iC3b-CR3 interaction is of high affinity and relies on minor contacts formed between CR3 and regions outside the iC3b thioester domain. Our results rationalize the more efficient phagocytosis elicited by iC3b than by C3dg and pave the way for the development of specific therapeutics for the treatment of inflammatory and neurodegenerative diseases that do not interfere with the recognition of noncomplement CR3 ligands.
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Affiliation(s)
- Rasmus K Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Goran Bajic
- Laboratory of Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA.,Department of Pediatrics, Harvard Medical School, Boston, MA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mehmet Sen
- Department of Biology and Biochemistry, University of Houston, Houston, TX
| | - Timothy A Springer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA; and
| | | | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark;
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36
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Lamers C, Plüss CJ, Ricklin D. The Promiscuous Profile of Complement Receptor 3 in Ligand Binding, Immune Modulation, and Pathophysiology. Front Immunol 2021; 12:662164. [PMID: 33995387 PMCID: PMC8118671 DOI: 10.3389/fimmu.2021.662164] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/12/2021] [Indexed: 12/19/2022] Open
Abstract
The β2-integrin receptor family has a broad spectrum of physiological functions ranging from leukocyte adhesion, cell migration, activation, and communication to the phagocytic uptake of cells and particles. Among the members of this family, complement receptor 3 (CR3; CD11b/CD18, Mac-1, αMβ2) is particularly promiscuous in its functional profile and ligand selectivity. There are close to 100 reported structurally unrelated ligands for CR3, and while many ligands appear to cluster at the αMI domain, molecular details about binding modes remain largely elusive. The versatility of CR3 is reflected in its functional portfolio, which includes prominent roles in the removal of invaders and cell debris, induction of tolerance and synaptic pruning, and involvement in the pathogenesis of numerous autoimmune and chronic inflammatory pathologies. While CR3 is an interesting therapeutic target for immune modulation due to these known pathophysiological associations, drug development efforts are limited by concerns of potential interference with host defense functions and, most importantly, an insufficient molecular understanding of the interplay between ligand binding and functional impact. Here, we provide a systematic summary of the various interaction partners of CR3 with a focus on binding mechanisms and functional implications. We also discuss the roles of CR3 as an immune receptor in health and disease, as an activation marker in research and diagnostics, and as a therapeutic target.
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Affiliation(s)
- Christina Lamers
- Molecular Pharmacy Unit, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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37
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Lokki AI, Teirilä L, Triebwasser M, Daly E, Bhattacharjee A, Uotila L, Llort Asens M, Kurki MI, Perola M, Auro K, Salmon JE, Daly M, Atkinson JP, Laivuori H, Fagerholm S, Meri S. Dysfunction of complement receptors CR3 (CD11b/18) and CR4 (CD11c/18) in pre-eclampsia: a genetic and functional study. BJOG 2021; 128:1282-1291. [PMID: 33539617 DOI: 10.1111/1471-0528.16660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To study genetic variants and their function within genes coding for complement receptors in pre-eclampsia. DESIGN A case-control study. SETTING Pre-eclampsia is a common vascular disease of pregnancy. The clearance of placenta-derived material is one of the functions of the complement system in pregnancy. POPULATION We genotyped 500 women with pre-eclamptic pregnancies and 190 pregnant women without pre-eclampsia, as controls, from the FINNPEC cohort, and 122 women with pre-eclamptic pregnancies and 1905 controls from the national FINRISK cohort. METHODS The functional consequences of genotypes discovered by targeted exomic sequencing were explored by analysing the binding of the main ligand iC3b to mutated CR3 or CR4, which were transiently expressed on the surface of COS-1 cells. MAIN OUTCOME MEASURES Allele frequencies were compared between pre-eclamptic pregnancies and controls in genetic studies. The functional consequences of selected variants were measured by binding assays. RESULTS The most significantly pre-eclampsia-linked CR3 variant M441K (P = 4.27E-4, OR = 1.401, 95% CI = 1.167-1.682) displayed a trend of increased adhesion to iC3b (P = 0.051). The CR4 variant A251T was found to enhance the adhesion of CR4 to iC3b, whereas W48R resulted in a decrease of the binding of CR4 to iC3b. CONCLUSIONS Results suggest that changes in complement-facilitated phagocytosis are associated with pre-eclampsia. Further studies are needed to ascertain whether aberrant CR3 and CR4 activity leads to altered pro- and anti-inflammatory cytokine responses in individuals carrying the associated variants, and the role of these receptors in pre-eclampsia pathogenesis. TWEETABLE ABSTRACT Genetic variants of complement receptors CR3 and CR4 have functional consequences that are associated with pre-eclampsia.
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Affiliation(s)
- A I Lokki
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Obstetrics and Gynecology, Faculty of Medicine and Health Technology, Tampere University Hospital, Tampere University, Tampere, Finland
| | - L Teirilä
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and immunology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - M Triebwasser
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - E Daly
- Hospital and Harvard Medical School, Boston, MA, USA
| | - A Bhattacharjee
- Herantis Pharma Plc, Espoo, Finland.,Neuroscience Center, HiLife, University of Helsinki, Helsinki, Finland
| | - L Uotila
- Research Services, University of Helsinki, Helsinki, Finland
| | - M Llort Asens
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - M I Kurki
- Neurosurgery of Neuro Center, Kuopio University Hospital, Finland.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - M Perola
- Department of Health, National Institute for Health and Welfare, Helsinki, Finland
| | - K Auro
- Department of Government Services, National Institute for Health and Welfare, Helsinki, Finland
| | - J E Salmon
- Hospital for Special Surgery-Weill Cornell Medicine, Department of Medicine, New York, NY, USA
| | - M Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA.,Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - J P Atkinson
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - H Laivuori
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Technology, Tampere University Hospital, Tampere University, Tampere, Finland.,Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - S Fagerholm
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - S Meri
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and immunology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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Sun Y, Xu B, Zhuge X, Tang F, Wang X, Gong Q, Chen R, Xue F, Dai J. Factor H Is Bound by Outer Membrane-Displayed Carbohydrate Metabolism Enzymes of Extraintestinal Pathogenic Escherichia coli and Contributes to Opsonophagocytosis Resistance in Bacteria. Front Cell Infect Microbiol 2021; 10:592906. [PMID: 33569353 PMCID: PMC7868385 DOI: 10.3389/fcimb.2020.592906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/11/2020] [Indexed: 01/15/2023] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) causes bloodstream infections in humans and animals. Complement escape is a prerequisite for bacteria to survive in the bloodstream. Factor H (FH) is an important regulatory protein of the complement system. In this study, ExPEC was found to bind FH from serum. However, the mechanisms of ExPEC binding to FH and then resistance to complement-mediated attacks remain unclear. Here, a method that combined desthiobiotin pull-down and liquid chromatography-tandem mass spectrometry was used to identify the FH-binding membrane proteins of ExPEC. Seven identified proteins, which all were carbohydrate metabolic enzymes (CMEs), including acetate kinase, fructose-bisphosphate aldolase, fumarate reductase flavoprotein subunit, L-lactate dehydrogenase, dihydrolipoamide dehydrogenase, phosphoenolpyruvate synthase, and pyruvate dehydrogenase, were verified to recruit FH from serum using GST pull-down and ELISA plate binding assay. The ELISA plate binding assay determined that these seven proteins bind to FH in a dose-dependent manner. Magnetic beads coupled with any one of seven proteins significantly reduced the FH recruitment of ExPEC (p < 0.05) Subsequently, immunofluorescence, colony blotting, and Western blotting targeting outer membrane proteins determined that these seven CMEs were located on the outer membrane of ExPEC. Furthermore, the FH recruitment levels and C3b deposition levels on bacteria were significantly increased and decreased in an FH-concentration-dependent manner, respectively (p < 0.05). The FH recruitment significantly enhanced the ability of ExPEC to resist the opsonophagocytosis of human macrophage THP-1 in an FH-concentration-dependent manner (p < 0.05), which revealed a new mechanism for ExPEC to escape complement-mediated killing. The identification of novel outer membrane-displayed CMEs which played a role in the FH recruitment contributes to the elucidation of the molecular mechanism of ExPEC pathogenicity.
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Affiliation(s)
- Yu Sun
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Bin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.,National Research Center of Veterinary Biologicals Engineering and Technology, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xiangkai Zhuge
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.,Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, China
| | - Fang Tang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Xuhang Wang
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Qianwen Gong
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Rui Chen
- Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Feng Xue
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Jianjun Dai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Laboratory of Animal Bacteriology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.,School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
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39
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Feng W, Nguyen H, Shen D, Deng H, Jiang Z, Podolnikova N, Ugarova T, Wang X. Structural Characterization of the Interaction between the α MI-Domain of the Integrin Mac-1 (α Mβ 2) and the Cytokine Pleiotrophin. Biochemistry 2021; 60:182-193. [PMID: 33427449 DOI: 10.1021/acs.biochem.0c00700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Integrin Mac-1 (αMβ2) is an adhesion receptor vital to many functions of myeloid leukocytes. It is also the most promiscuous member of the integrin family capable of recognizing a broad range of ligands. In particular, its ligand-binding αMI-domain is known to bind cationic proteins/peptides depleted in acidic residues. This contradicts the canonical ligand-binding mechanism of αI-domains, which requires an acidic amino acid in the ligand to coordinate the divalent cation within the metal ion-dependent adhesion site (MIDAS) of αI-domains. The lack of acidic amino acids in the αMI-domain-binding sequences suggests the existence of an as-yet uncharacterized interaction mechanism. In the present study, we analyzed interactions of the αMI-domain with a representative Mac-1 ligand, the cationic cytokine pleiotrophin (PTN). Through NMR chemical shift perturbation analysis, cross saturation, NOESY, and mutagenesis studies, we found the interaction between the αMI-domain and PTN is divalent cation-independent and mediated mostly by hydrophobic contacts between the N-terminal domain of PTN and residues in the α5-β5 loop of αMI-domain. The observation that increased ionic strength weakens the interaction between the proteins indicates electrostatic forces may also play a significant role in the binding. On the basis of the results from these experiments, we formulated a model of the interaction between the αMI-domain and PTN.
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40
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Choi J, Buyannemekh D, Nham SU. Moieties of Complement iC3b Recognized by the I-domain of Integrin αXβ2. Mol Cells 2020; 43:1023-1034. [PMID: 33372665 PMCID: PMC7772510 DOI: 10.14348/molcells.2020.0197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/17/2020] [Indexed: 11/27/2022] Open
Abstract
Complement fragment iC3b serves as a major opsonin for facilitating phagocytosis via its interaction with complement receptors CR3 and CR4, also known by their leukocyte integrin family names, αMβ2 and αXβ2, respectively. Although there is general agreement that iC3b binds to the αM and αX I-domains of the respective β2-integrins, much less is known regarding the regions of iC3b contributing to the αX I-domain binding. In this study, using recombinant αX I-domain, as well as recombinant fragments of iC3b as candidate binding partners, we have identified two distinct binding moieties of iC3b for the αX I-domain. They are the C3 convertase-generated N-terminal segment of the C3b α'- chain (α'NT) and the factor I cleavage-generated N-terminal segment in the CUBf region of α-chain. Additionally, we have found that the CUBf segment is a novel binding moiety of iC3b for the αM I-domain. The CUBf segment shows about a 2-fold higher binding activity than the α'NT for αX I-domain. We also have shown the involvement of crucial acidic residues on the iC3b side of the interface and basic residues on the I-domain side.
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Affiliation(s)
- Jeongsuk Choi
- Department of Biology, Kangwon National University, Chuncheon 2434, Korea
| | | | - Sang-Uk Nham
- Division of Science Education, Kangwon National University, Chuncheon 4341, Korea
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41
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Development of Fish Immunity and the Role of β-Glucan in Immune Responses. Molecules 2020; 25:molecules25225378. [PMID: 33213001 PMCID: PMC7698520 DOI: 10.3390/molecules25225378] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/21/2020] [Accepted: 11/04/2020] [Indexed: 02/06/2023] Open
Abstract
Administration of β-glucans through various routes, including immersion, dietary inclusion, or injection, have been found to stimulate various facets of immune responses, such as resistance to infections and resistance to environmental stress. β-Glucans used as an immunomodulatory food supplement have been found beneficial in eliciting immunity in commercial aquaculture. Despite extensive research involving more than 3000 published studies, knowledge of the receptors involved in recognition of β-glucans, their downstream signaling, and overall mechanisms of action is still lacking. The aim of this review is to summarize and discuss what is currently known about of the use of β-glucans in fish.
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42
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Sharma S, Bhatnagar R, Gaur D. Complement Evasion Strategies of Human Pathogenic Bacteria. Indian J Microbiol 2020; 60:283-296. [PMID: 32655196 PMCID: PMC7329968 DOI: 10.1007/s12088-020-00872-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 04/07/2020] [Indexed: 12/21/2022] Open
Abstract
Human pathogens need to overcome an elaborate network of host defense mechanisms in order to establish their infection, colonization, proliferation and eventual dissemination. The interaction of pathogens with different effector molecules of the immune system results in their neutralization and elimination from the host. The complement system is one such integral component of innate immunity that is critically involved in the early recognition and elimination of the pathogen. Hence, under this immune pressure, all virulent pathogens capable of inducing active infections have evolved immune evasive strategies that primarily target the complement system, which plays an essential and central role for host defense. Recent reports on several bacterial pathogens have elucidated the molecular mechanisms underlying complement evasion, inhibition of opsonic phagocytosis and cell lysis. This review aims to comprehensively summarize the recent findings on the various strategies adopted by pathogenic bacteria to escape complement-mediated clearance.
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Affiliation(s)
- Shikhar Sharma
- Laboratory of Malaria and Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067 India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Deepak Gaur
- Laboratory of Malaria and Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067 India
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43
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Zarantonello A, Presumey J, Simoni L, Yalcin E, Fox R, Hansen A, Olesen HG, Thiel S, Johnson MB, Stevens B, Laursen NS, Carroll MC, Andersen GR. An Ultrahigh-Affinity Complement C4b-Specific Nanobody Inhibits In Vivo Assembly of the Classical Pathway Proconvertase. THE JOURNAL OF IMMUNOLOGY 2020; 205:1678-1694. [PMID: 32769120 DOI: 10.4049/jimmunol.2000528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/09/2020] [Indexed: 01/07/2023]
Abstract
The classical and lectin pathways of the complement system are important for the elimination of pathogens and apoptotic cells and stimulation of the adaptive immune system. Upon activation of these pathways, complement component C4 is proteolytically cleaved, and the major product C4b is deposited on the activator, enabling assembly of a C3 convertase and downstream alternative pathway amplification. Although excessive activation of the lectin and classical pathways contributes to multiple autoimmune and inflammatory diseases and overexpression of a C4 isoform has recently been linked to schizophrenia, a C4 inhibitor and structural characterization of the convertase formed by C4b is lacking. In this study, we present the nanobody hC4Nb8 that binds with picomolar affinity to human C4b and potently inhibits in vitro complement C3 deposition through the classical and lectin pathways in human serum and in mouse serum. The crystal structure of the C4b:hC4Nb8 complex and a three-dimensional reconstruction of the C4bC2 proconvertase obtained by electron microscopy together rationalize how hC4Nb8 prevents proconvertase assembly through recognition of a neoepitope exposed in C4b and reveals a unique C2 conformation compared with the alternative pathway proconvertase. On human induced pluripotent stem cell-derived neurons, the nanobody prevents C3 deposition through the classical pathway. Furthermore, hC4Nb8 inhibits the classical pathway-mediated immune complex delivery to follicular dendritic cells in vivo. The hC4Nb8 represents a novel ultrahigh-affinity inhibitor of the classical and lectin pathways of the complement cascade under both in vitro and in vivo conditions.
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Affiliation(s)
| | - Jessy Presumey
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Léa Simoni
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Esra Yalcin
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Rachel Fox
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Annette Hansen
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Heidi Gytz Olesen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Matthew B Johnson
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115
| | - Beth Stevens
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115.,Department of Neurology, Harvard Medical School, Boston, MA 02115.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115; and
| | - Nick Stub Laursen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Michael C Carroll
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115.,Department of Pediatrics, Harvard Medical School, Boston, MA 02115
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark;
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44
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Autotransporter-Mediated Display of Complement Receptor Ligands by Gram-Negative Bacteria Increases Antibody Responses and Limits Disease Severity. Pathogens 2020; 9:pathogens9050375. [PMID: 32422907 PMCID: PMC7281241 DOI: 10.3390/pathogens9050375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/06/2020] [Accepted: 05/11/2020] [Indexed: 12/13/2022] Open
Abstract
The targeting of immunogens/vaccines to specific immune cells is a promising approach for amplifying immune responses in the absence of exogenous adjuvants. However, the targeting approaches reported thus far require novel, labor-intensive reagents for each vaccine and have primarily been shown as proof-of-concept with isolated proteins and/or inactivated bacteria. We have engineered a plasmid-based, complement receptor-targeting platform that is readily applicable to live forms of multiple gram-negative bacteria, including, but not limited to, Escherichia coli, Klebsiella pneumoniae, and Francisella tularensis. Using F. tularensis as a model, we find that targeted bacteria show increased binding and uptake by macrophages, which coincides with increased p38 and p65 phosphorylation. Mice vaccinated with targeted bacteria produce higher titers of specific antibody that recognizes a greater diversity of bacterial antigens. Following challenge with homologous or heterologous isolates, these mice exhibited less weight loss and/or accelerated weight recovery as compared to counterparts vaccinated with non-targeted immunogens. Collectively, these findings provide proof-of-concept for plasmid-based, complement receptor-targeting of live gram-negative bacteria.
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45
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Structural basis of the leukocyte integrin Mac-1 I-domain interactions with the platelet glycoprotein Ib. Blood Adv 2020; 3:1450-1459. [PMID: 31053572 DOI: 10.1182/bloodadvances.2018027011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/10/2019] [Indexed: 12/14/2022] Open
Abstract
Cell-surface receptor interactions between leukocyte integrin macrophage-1 antigen (Mac-1, also known as CR3, αMβ2, CD11b/CD18) and platelet glycoprotein Ibα (GPIbα) are critical to vascular inflammation. To define the key residues at the binding interface, we used nuclear magnetic resonance (NMR) to assign the spectra of the mouse Mac-1 I-domain and mapped the residues contacting the mouse GPIbα N-terminal domain (GPIbαN) to the locality of the integrin metal ion-dependant adhesion site (MIDAS) surface. We next determined the crystal structures of the mouse GPIbαN and Mac-1 I-domain to 2 Å and 2.5 Å resolution, respectively. The mouse Mac-1 I-domain crystal structure reveals an active conformation that is stabilized by a crystal contact from the α7-helix with a glutamate side chain completing the octahedral coordination sphere of the MIDAS Mg2+ ion. The amino acid sequence of the α7-helix and disposition of the glutamic acid matches the C-terminal capping region α-helix of GPIbα effectively acting as a ligand mimetic. Using these crystal structures in combination with NMR measurements and docking analysis, we developed a model whereby an acidic residue from the GPIbα leucine-rich repeat (LRR) capping α-helix coordinates directly to the Mac-1 MIDAS Mg2+ ion. The Mac-1:GPIbαN complex involves additional interactions consolidated by an elongated pocket flanking the GPIbαN LRR capping α-helix. The GPIbαN α-helix has an HxxxE motif, which is equivalent by homology to RxxxD from the human GPIbαN. Subsequent mutagenesis of residues at this interface, coupled with surface plasmon resonance studies, confirmed the importance of GPIbαN residues H218, E222, and the Mac-1 MIDAS residue T209 to formation of the complex.
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46
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Pedersen H, Jensen RK, Hansen AG, Gadeberg TAF, Thiel S, Laursen NS, Andersen GR. A C3-specific nanobody that blocks all three activation pathways in the human and murine complement system. J Biol Chem 2020; 295:8746-8758. [PMID: 32376685 DOI: 10.1074/jbc.ra119.012339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
The complement system is a tightly controlled proteolytic cascade in the innate immune system, which tags intruding pathogens and dying host cells for clearance. An essential protein in this process is complement component C3. Uncontrolled complement activation has been implicated in several human diseases and disorders and has spurred the development of therapeutic approaches that modulate the complement system. Here, using purified proteins and several biochemical assays and surface plasmon resonance, we report that our nanobody, hC3Nb2, inhibits C3 deposition by all complement pathways. We observe that the hC3Nb2 nanobody binds human native C3 and its degradation products with low nanomolar affinity and does not interfere with the endogenous regulation of C3b deposition mediated by Factors H and I. Using negative stain EM analysis and functional assays, we demonstrate that hC3Nb2 inhibits the substrate-convertase interaction by binding to the MG3 and MG4 domains of C3 and C3b. Furthermore, we notice that hC3Nb2 is cross-reactive and inhibits the lectin and alternative pathway in murine serum. We conclude that hC3Nb2 is a potent, general, and versatile inhibitor of the human and murine complement cascades. Its cross-reactivity suggests that this nanobody may be valuable for analysis of complement activation within animal models of both acute and chronic diseases.
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Affiliation(s)
- Henrik Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Rasmus K Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Trine A F Gadeberg
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Nick S Laursen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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47
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Torres-Gomez A, Cabañas C, Lafuente EM. Phagocytic Integrins: Activation and Signaling. Front Immunol 2020; 11:738. [PMID: 32425937 PMCID: PMC7203660 DOI: 10.3389/fimmu.2020.00738] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/31/2020] [Indexed: 01/06/2023] Open
Abstract
Phagocytic integrins are endowed with the ability to engulf and dispose of particles of different natures. Evolutionarily conserved from worms to humans, they are involved in pathogen elimination and apoptotic and tumoral cell clearance. Research in the field of integrin-mediated phagocytosis has shed light on the molecular events controlling integrin activation and their effector functions. However, there are still some aspects of the regulation of the phagocytic process that need to be clarified. Here, we have revised the molecular events controlling phagocytic integrin activation and the downstream signaling driving particle engulfment, and we have focused particularly on αMβ2/CR3, αXβ2/CR4, and a brief mention of αVβ5/αVβ3integrins.
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Affiliation(s)
- Alvaro Torres-Gomez
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Carlos Cabañas
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain.,Severo Ochoa Center for Molecular Biology (CSIC-UAM), Madrid, Spain
| | - Esther M Lafuente
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain
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48
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Zheng Y, Leftheris K. Insights into Protein–Ligand Interactions in Integrin Complexes: Advances in Structure Determinations. J Med Chem 2020; 63:5675-5696. [DOI: 10.1021/acs.jmedchem.9b01869] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Yajun Zheng
- Pliant Therapeutics, South San Francisco, California 94080, United States
| | - Katerina Leftheris
- Pliant Therapeutics, South San Francisco, California 94080, United States
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49
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Juul-Madsen K, Qvist P, Bendtsen KL, Langkilde AE, Vestergaard B, Howard KA, Dehesa-Etxebeste M, Paludan SR, Andersen GR, Jensen PH, Otzen DE, Romero-Ramos M, Vorup-Jensen T. Size-Selective Phagocytic Clearance of Fibrillar α-Synuclein through Conformational Activation of Complement Receptor 4. THE JOURNAL OF IMMUNOLOGY 2020; 204:1345-1361. [PMID: 31969389 DOI: 10.4049/jimmunol.1900494] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/18/2019] [Indexed: 12/19/2022]
Abstract
Aggregation of α-synuclein (αSN) is an important histological feature of Parkinson disease. Recent studies showed that the release of misfolded αSN from human and rodent neurons is relevant to the progression and spread of αSN pathology. Little is known, however, about the mechanisms responsible for clearance of extracellular αSN. This study found that human complement receptor (CR) 4 selectively bound fibrillar αSN, but not monomeric species. αSN is an abundant protein in the CNS, which potentially could overwhelm clearance of cytotoxic αSN species. The selectivity of CR4 toward binding fibrillar αSN consequently adds an important αSN receptor function for maintenance of brain homeostasis. Based on the recently solved structures of αSN fibrils and the known ligand preference of CR4, we hypothesize that the parallel monomer stacking in fibrillar αSN creates a known danger-associated molecular pattern of stretches of anionic side chains strongly bound by CR4. Conformational change in the receptor regulated tightly clearance of fibrillar αSN by human monocytes. The induced change coupled concomitantly with phagolysosome formation. Data mining of the brain transcriptome in Parkinson disease patients supported CR4 as an active αSN clearance mechanism in this disease. Our results associate an important part of the innate immune system, namely complement receptors, with the central molecular mechanisms of CNS protein aggregation in neurodegenerative disorders.
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Affiliation(s)
- Kristian Juul-Madsen
- Biophysical Immunology Laboratory, Aarhus University, DK-8000 Aarhus C, Denmark.,Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Per Qvist
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus University, DK-8000 Aarhus C, Denmark.,iSEQ, Centre for Integrative Sequencing, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Kirstine L Bendtsen
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Annette E Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Bente Vestergaard
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
| | - Kenneth A Howard
- Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Martxel Dehesa-Etxebeste
- Neuroscience Area, Biodonostia Research Institute, 20014 Donostia, San Sebastian, Spain.,CIBERNED, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Poul Henning Jensen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,DANDRITE-Danish Research Institute of Translational Neuroscience, Aarhus University, DK-8000 Aarhus C, Denmark; and
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Marina Romero-Ramos
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,DANDRITE-Danish Research Institute of Translational Neuroscience, Aarhus University, DK-8000 Aarhus C, Denmark; and.,NEURODIN AU IDEAS Center, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Thomas Vorup-Jensen
- Biophysical Immunology Laboratory, Aarhus University, DK-8000 Aarhus C, Denmark; .,Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark.,NEURODIN AU IDEAS Center, Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
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50
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Molecular mechanism of leukocidin GH-integrin CD11b/CD18 recognition and species specificity. Proc Natl Acad Sci U S A 2019; 117:317-327. [PMID: 31852826 PMCID: PMC6955338 DOI: 10.1073/pnas.1913690116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Staphylococcus aureus is one of the most virulent bacterial pathogens and, in particular, has the richest repertoire of cytotoxins: A single bacterium can secrete 6 different β-barrel pore-forming toxins, with different cell type and species specificities. Each toxin engages specific receptors on target cells, but the role the receptor plays in the pore-formation process is poorly understood. Here, we determine the crystal structures of a very potent S. aureus leukocidin (LukGH) in complex with its receptor (CD11b) from a sensitive (human) and an insensitive (murine) host, and track the receptor involvement in different steps on the pore-formation pathway. These results advance the knowledge of receptor-mediated leukocidin pore formation and open ways for antileukocidin and anti-S. aureus approaches. Host–pathogen interactions are central to understanding microbial pathogenesis. The staphylococcal pore-forming cytotoxins hijack important immune molecules but little is known about the underlying molecular mechanisms of cytotoxin–receptor interaction and host specificity. Here we report the structures of a staphylococcal pore-forming cytotoxin, leukocidin GH (LukGH), in complex with its receptor (the α-I domain of complement receptor 3, CD11b-I), both for the human and murine homologs. We observe 2 binding interfaces, on the LukG and the LukH protomers, and show that human CD11b-I induces LukGH oligomerization in solution. LukGH binds murine CD11b-I weakly and is inactive toward murine neutrophils. Using a LukGH variant engineered to bind mouse CD11b-I, we demonstrate that cytolytic activity does not only require binding but also receptor-dependent oligomerization. Our studies provide an unprecedented insight into bicomponent leukocidin–host receptor interaction, enabling the development of antitoxin approaches and improved animal models to explore these approaches.
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