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Vorup-Jensen T, Jensen RK. Structural Immunology of Complement Receptors 3 and 4. Front Immunol 2018; 9:2716. [PMID: 30534123 PMCID: PMC6275225 DOI: 10.3389/fimmu.2018.02716] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 11/05/2018] [Indexed: 01/10/2023] Open
Abstract
Complement receptors (CR) 3 and 4 belong to the family of beta-2 (CD18) integrins. CR3 and CR4 are often co-expressed in the myeloid subsets of leukocytes, but they are also found in NK cells and activated T and B lymphocytes. The heterodimeric ectodomain undergoes considerable conformational change in order to switch the receptor from a structurally bent, ligand-binding in-active state into an extended, ligand-binding active state. CR3 binds the C3d fragment of C3 in a way permitting CR2 also to bind concomitantly. This enables a hand-over of complement-opsonized antigens from the cell surface of CR3-expressing macrophages to the CR2-expressing B lymphocytes, in consequence acting as an antigen presentation mechanism. As a more enigmatic part of their functions, both CR3 and CR4 bind several structurally unrelated proteins, engineered peptides, and glycosaminoglycans. No consensus motif in the proteinaceous ligands has been established. Yet, the experimental evidence clearly suggest that the ligands are primarily, if not entirely, recognized by a single site within the receptors, namely the metal-ion dependent adhesion site (MIDAS). Comparison of some recent identified ligands points to CR3 as inclined to bind positively charged species, while CR4, by contrast, binds strongly negative-charged species, in both cases with the critical involvement of deprotonated, acidic groups as ligands for the Mg2+ ion in the MIDAS. These properties place CR3 and CR4 firmly within the realm of modern molecular medicine in several ways. The expression of CR3 and CR4 in NK cells was recently demonstrated to enable complement-dependent cell cytotoxicity toward antibody-coated cancer cells as part of biological therapy, constituting a significant part of the efficacy of such treatment. With the flexible principles of ligand recognition, it is also possible to propose a response of CR3 and CR4 to existing medicines thereby opening a possibility of drug repurposing to influence the function of these receptors. Here, from advances in the structural and cellular immunology of CR3 and CR4, we review insights on their biochemistry and functions in the immune system.
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Affiliation(s)
- Thomas Vorup-Jensen
- Biophysical Immunology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
| | - Rasmus Kjeldsen Jensen
- Department of Molecular Biology and Genetics-Structural Biology, Aarhus University, Aarhus, Denmark
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Støy S, Sandahl TD, Hansen AL, Deleuran B, Vorup-Jensen T, Vilstrup H, Kragstrup TW. Decreased monocyte shedding of the migration inhibitor soluble CD18 in alcoholic hepatitis. Clin Transl Gastroenterol 2018; 9:160. [PMID: 29904132 PMCID: PMC6002386 DOI: 10.1038/s41424-018-0022-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/23/2018] [Accepted: 03/13/2018] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVES During alcoholic hepatitis (AH) monocytes traverse the vascular boundaries and massively invade the liver. In principle, tissue extravasation can be limited through shedding of CD18 integrins from leukocytes, including monocytes. The soluble (s) product sCD18 conceals adhesion receptors on the endothelium, which reduces monocyte extravasation. In AH, monocytes are dysfunctional, but whether this involves their self-generated anti-migration is unknown. Our aim was, therefore, to investigate monocyte CD18 dynamics in AH. METHODS We studied 50 AH patients and 20 healthy controls. We measured monocyte expression and conformational activation of CD18, plasma (P)-sCD18, stimulated in vitro CD18 shedding and P-sCD18 in a short-term chronic-binge mouse model. RESULTS AH-derived monocytes had a 30-60% higher expression of active CD18 receptors (p < 0.01), but the sCD18 concentration per monocyte was reduced in vivo by 30% and in vitro by 120% (p < 0.01). Ethanol reduced the in vitro shedding of CD18 in the patients only. TNFα increased sCD18 concentration per monocyte, but less so in the patients (p < 0.04). P-sCD18 per monocyte was inversely related to disease severity. In early alcoholic liver disease, P-sCD18 was decreased in the mouse model. CONCLUSIONS The monocyte CD18 integrins are highly activated in AH and the single monocyte shedding of CD18 was decreased favoring tissue extravasation. Alcohol in itself and altered monocyte responsiveness to TNFα may explain this lowered shedding. TRANSLATIONAL IMPACT The contribution of this mechanism to the excessive monocyte liver infiltration in AH should be further explored as it may serve as a potential therapeutic target to limit liver inflammation.
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Affiliation(s)
- Sidsel Støy
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
| | | | | | - Bent Deleuran
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Tue Wenzel Kragstrup
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
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Kragstrup TW, Juul-Madsen K, Christiansen SH, Zhang X, Krog J, Vorup-Jensen T, Kjaergaard AG. Altered levels of soluble CD18 may associate immune mechanisms with outcome in sepsis. Clin Exp Immunol 2017; 190:258-267. [PMID: 28714582 DOI: 10.1111/cei.13016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2017] [Indexed: 12/26/2022] Open
Abstract
The pathogenesis of sepsis involves a dual inflammatory response, with a hyperinflammatory phase followed by, or in combination with, a hypoinflammatory phase. The adhesion molecules lymphocyte function-associated antigen (LFA-1) (CD11a/CD18) and macrophage-1 (Mac-1) (CD11b/CD18) support leucocyte adhesion to intercellular adhesion molecules and phagocytosis through complement opsonization, both processes relevant to the immune response during sepsis. Here, we investigate the role of soluble (s)CD18 in sepsis with emphasis on sCD18 as a mechanistic biomarker of immune reactions and outcome of sepsis. sCD18 levels were measured in 15 septic and 15 critically ill non-septic patients. Fifteen healthy volunteers served as controls. CD18 shedding from human mononuclear cells was increased in vitro by several proinflammatory mediators relevant in sepsis. sCD18 inhibited cell adhesion to the complement fragment iC3b, which is a ligand for CD11b/CD18, also known as Mac-1 or complement receptor 3. Serum sCD18 levels in sepsis non-survivors displayed two distinct peaks permitting a partitioning into two groups, namely sCD18 'high' and sCD18 'low', with median levels of sCD18 at 2158 mU/ml [interquartile range (IQR) 2093-2811 mU/ml] and 488 mU/ml (IQR 360-617 mU/ml), respectively, at the day of intensive care unit admission. Serum sCD18 levels partitioned sepsis non-survivors into one group of 'high' sCD18 and low CRP and another group with 'low' sCD18 and high C-reactive protein. Together with the mechanistic data generated in vitro, we suggest the partitioning in sCD18 to reflect a compensatory anti-inflammatory response syndrome and hyperinflammation, respectively, manifested as part of sepsis.
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Affiliation(s)
- T W Kragstrup
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - K Juul-Madsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - X Zhang
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - J Krog
- Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.,Department of Anaesthesiology and Intensive Care, Randers Regional Hospital, Randers, Denmark
| | - T Vorup-Jensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - A G Kjaergaard
- Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark.,Department of Anaesthesiology and Intensive Care, Randers Regional Hospital, Randers, Denmark
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Kragstrup TW, Jalilian B, Keller KK, Zhang X, Laustsen JK, Stengaard-Pedersen K, Hetland ML, Hørslev-Petersen K, Junker P, Østergaard M, Hauge EM, Hvid M, Vorup-Jensen T, Deleuran B. Changes in Soluble CD18 in Murine Autoimmune Arthritis and Rheumatoid Arthritis Reflect Disease Establishment and Treatment Response. PLoS One 2016; 11:e0148486. [PMID: 26849368 PMCID: PMC4743942 DOI: 10.1371/journal.pone.0148486] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 01/19/2016] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION In rheumatoid arthritis (RA) immune activation and presence of autoantibodies may precede clinical onset of disease, and joint destruction can progress despite remission. However, the underlying temporal changes of such immune system abnormalities in the inflammatory response during treat-to-target strategies remain poorly understood. We have previously reported low levels of the soluble form of CD18 (sCD18) in plasma from patients with chronic RA and spondyloarthritis. Here, we study the changes of sCD18 before and during treatment of early RA and following arthritis induction in murine models of rheumatoid arthritis. METHODS The level of sCD18 was analyzed with a time-resolved immunoflourometric assay in 1) plasma from early treatment naïve RA patients during a treat-to-target strategy (the OPERA cohort), 2) plasma from chronic RA patients, 3) serum from SKG and CIA mice following arthritis induction, and 4) supernatants from synovial fluid mononuclear cells (SFMCs) and peripheral blood mononuclear cells (PBMCs) from 6 RA patients cultured with TNFα or adalimumab. RESULTS Plasma levels of sCD18 were decreased in chronic RA patients compared with early RA patients and in early RA patients compared with healthy controls. After 12 months of treatment the levels in early RA patients were similar to healthy controls. This normalization of plasma sCD18 levels was more pronounced in patients with very early disease who achieved an early ACR response. Plasma sCD18 levels were associated with radiographic progression. Correspondingly, the serum level of sCD18 was decreased in SKG mice 6 weeks after arthritis induction compared with healthy littermates. The sCD18 levels in both SKG and CIA mice exhibited a biphasic course after arthritis induction with an initial increase above baseline followed by a decline. Shedding of CD18 from RA SFMC and RA PBMC cultures was increased by TNFα and decreased by adalimumab. CONCLUSIONS The plasma sCD18 levels were altered in patients with RA, in mice with autoimmune arthritis and in cell cultures treated with TNFα and adalimumab. Decreased levels of plasma sCD18 could reflect autoimmunity in transition from early to chronic disease and normalization in response to treatment could reflect autoimmunity in remission.
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Affiliation(s)
- Tue Wenzel Kragstrup
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
- * E-mail:
| | - Babak Jalilian
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Xianwei Zhang
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Merete Lund Hetland
- Copenhagen Center for Arthritis Research, Rigshospitalet, Glostrup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Mikkel Østergaard
- Copenhagen Center for Arthritis Research, Rigshospitalet, Glostrup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Ellen-Margrethe Hauge
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Malene Hvid
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Bent Deleuran
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Bech R, Jalilian B, Agger R, Iversen L, Erlandsen M, Otkjaer K, Johansen C, Paludan SR, Rosenberg CA, Kragballe K, Vorup-Jensen T. Interleukin 20 regulates dendritic cell migration and expression of co-stimulatory molecules. MOLECULAR AND CELLULAR THERAPIES 2016; 4:1. [PMID: 26819710 PMCID: PMC4728801 DOI: 10.1186/s40591-016-0046-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/18/2016] [Indexed: 01/04/2023]
Abstract
Background Psoriasis is an inflammatory disease characterized by leukocyte skin infiltration. Interestingly, recent works suggest that the migration of dendritic cells (DCs) is abnormal in psoriatic skin. DCs have significant role in regulating the function of T lymphocytes, at least in part influenced by the local environment of cytokines. In psoriatic skin lesions the expression of IL-20 is highly up-regulated. It is unclear if this cytokine has any influence on DCs. Methods Here, we investigated the influence of IL-20 in monocyte-derived dendritic cell (MDDCs) in vitro. This work addressed IL-20 effects on DC maturation, receptor expression and signaling. By use of extra cellular matrix components mimicking the skin environment, we also studied the functional effects of IL-20 on the chemotactic migration of DCs. Based on the recent finding that CD18 integrin are shed during migration of myeloid leukocytes, the concentration of these adhesion molecules was measured in MDDCs culture supernatants post migration. Results Following stimulation with IL-20, immature human MDDCs enhanced the expression of the co-stimulatory molecule CD86, further enabling activation of the p38 MAPK, but not the STAT3, pathway. IL-20 increased the migration of MDDCs in a biphasic response narrowly controlled by the interleukin concentration. A concomitant change in the shedding of CD18 integrins suggested that these adhesion molecules play a role in the migration of the MDDCs through the extracellular matrix layer. Conclusion Taken together, our findings points to a possible, yet subtle, role of IL-20 in DCs migration. The biphasic response suggests that the aberrant IL-20 expression in psoriasis impedes DC migration, which could be a part of the processes that precipitates the dysregulated inflammatory response associated with this disease. Electronic supplementary material The online version of this article (doi:10.1186/s40591-016-0046-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rikke Bech
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Babak Jalilian
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ralf Agger
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Lars Iversen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Mogens Erlandsen
- Department of Public Health - Biostatistics, Aarhus University, Aarhus, Denmark
| | - Kristian Otkjaer
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Claus Johansen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Knud Kragballe
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Thomas Vorup-Jensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Interdisiplinary Nanoscience Center, Aarhus University, Aarhus, Denmark.,Biophysical Immunology Laboratory, Department of Biomedicine, Aarhus University, The Bartholin Building (1240), Wilhelm Meyers Allé 4, DK-8000 Aarhus C, Denmark
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Bech R, Jalilian B, Agger R, Iversen L, Erlandsen M, Otkjaer K, Johansen C, Paludan SR, Rosenberg CA, Kragballe K, Vorup-Jensen T. Interleukin 20 regulates dendritic cell migration and expression of co-stimulatory molecules. MOLECULAR AND CELLULAR THERAPIES 2016; 4:1. [PMID: 26819710 PMCID: PMC4728801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/18/2016] [Indexed: 11/21/2023]
Abstract
BACKGROUND Psoriasis is an inflammatory disease characterized by leukocyte skin infiltration. Interestingly, recent works suggest that the migration of dendritic cells (DCs) is abnormal in psoriatic skin. DCs have significant role in regulating the function of T lymphocytes, at least in part influenced by the local environment of cytokines. In psoriatic skin lesions the expression of IL-20 is highly up-regulated. It is unclear if this cytokine has any influence on DCs. METHODS Here, we investigated the influence of IL-20 in monocyte-derived dendritic cell (MDDCs) in vitro. This work addressed IL-20 effects on DC maturation, receptor expression and signaling. By use of extra cellular matrix components mimicking the skin environment, we also studied the functional effects of IL-20 on the chemotactic migration of DCs. Based on the recent finding that CD18 integrin are shed during migration of myeloid leukocytes, the concentration of these adhesion molecules was measured in MDDCs culture supernatants post migration. RESULTS Following stimulation with IL-20, immature human MDDCs enhanced the expression of the co-stimulatory molecule CD86, further enabling activation of the p38 MAPK, but not the STAT3, pathway. IL-20 increased the migration of MDDCs in a biphasic response narrowly controlled by the interleukin concentration. A concomitant change in the shedding of CD18 integrins suggested that these adhesion molecules play a role in the migration of the MDDCs through the extracellular matrix layer. CONCLUSION Taken together, our findings points to a possible, yet subtle, role of IL-20 in DCs migration. The biphasic response suggests that the aberrant IL-20 expression in psoriasis impedes DC migration, which could be a part of the processes that precipitates the dysregulated inflammatory response associated with this disease.
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Affiliation(s)
- Rikke Bech
- />Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
- />Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Babak Jalilian
- />Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ralf Agger
- />Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Lars Iversen
- />Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Mogens Erlandsen
- />Department of Public Health - Biostatistics, Aarhus University, Aarhus, Denmark
| | - Kristian Otkjaer
- />Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Claus Johansen
- />Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Knud Kragballe
- />Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Thomas Vorup-Jensen
- />Department of Biomedicine, Aarhus University, Aarhus, Denmark
- />Interdisiplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
- />Biophysical Immunology Laboratory, Department of Biomedicine, Aarhus University, The Bartholin Building (1240), Wilhelm Meyers Allé 4, DK-8000 Aarhus C, Denmark
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