| 1. |
- Autio, Anu, et al.
(författare)
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SIRPα - CD47 axis regulates dendritic cell-T cell interactions and TCR activation during T cell priming in spleen
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:4 April
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Tidskriftsartikel (refereegranskat)abstract
- The SIRPα-CD47 axis plays an important role in T cell recruitment to sites of immune reaction and inflammation but its role in T cell antigen priming is incompletely understood. Employing OTII TCR transgenic mice bred to Cd47-/- (Cd47KO) or SKI mice, a knock-in transgenic animal expressing non-signaling cytoplasmic-truncated SIRPα, we investigated how the SIRPα-CD47 axis contributes to antigen priming. Here we show that adoptive transfer of Cd47KO or SKI Ova-specific CD4+ T cells (OTII) into Cd47KO and SKI recipients, followed by Ova immunization, elicited reduced T cell division and proliferation indices, increased apoptosis, and reduced expansion compared to transfer into WT mice. We confirmed prior reports that splenic T cell zone, CD4+ conventional dendritic cells (cDCs) and CD4+ T cell numbers were reduced in Cd47KO and SKI mice. We report that in vitro derived DCs from Cd47KO and SKI mice exhibited impaired migration in vivo and exhibited reduced CD11c+ DC proximity to OTII T cells in T cell zones after Ag immunization, which correlates with reduced TCR activation in transferred OTII T cells. These findings suggest that reduced numbers of CD4+ cDCs and their impaired migration contributes to reduced T cell-DC proximity in splenic T cell zone and reduced T cell TCR activation, cell division and proliferation, and indirectly increased T cell apoptosis.
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| 2. |
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| 3. |
- Dunér, Pontus, et al.
(författare)
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Immune responses against aldehyde-modified laminin accelerate atherosclerosis in Apoe(-/-) mice.
- 2010
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Ingår i: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 212:2, s. 457-465
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: LDL oxidation in the vascular wall is associated with aldehyde modification of surrounding extracellular matrix proteins that may target autoimmune responses against vascular tissues. Here we investigated the possible influence of immunity against a malondialdehyde (MDA)-modified form of the basement membrane protein laminin on atherosclerosis. METHODS AND RESULTS: IgM and IgG autoantibodies were present in human plasma and a prospective clinical study demonstrated that individuals who later suffered from acute cardiovascular events had lower levels of MDA-laminin antibodies compared to those in the control group. Immunohistochemical analysis of atherosclerotic plaques from Apoe(-/-) mice demonstrated co-localization between laminin and MDA epitopes, however MDA-laminin IgG was absent in mouse plasma. To determine the effect of MDA-laminin immunity, Apoe(-/-) mice were immunized with MDA-laminin. Analysis of circulating leukocytes at 12 weeks demonstrated increased T-cell activation, expansion of Th17 cells and a lower fraction of regulatory T cells (Tregs) in mice immunized with MDA-laminin. At 25 weeks, aortic atherosclerosis was increased by more than 60% in mice immunized with MDA-laminin, together with increased levels of MDA-laminin IgG1 and MDA-laminin-specific T-cells expressing IL-2, IL-4 and IL-6 in the spleen. CONCLUSION: The clinical observations suggest that immune responses against MDA-laminin may be involved in the development of cardiovascular disease in humans. Furthermore, observations in mice provide evidence for the presence of aldehyde-modified laminin in atherosclerotic lesions and demonstrate that induction of an immune response against these structures is associated with activation of Th17 cells, reduced fraction of Tregs and a more aggressive development of atherosclerosis.
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| 4. |
- Engelbertsen, Daniel
(författare)
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Adaptive Immunity in Cardiovascular Disease
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis, thickening of the major arteries, is a chronic disease leading to cardiovascular disease (CVD) such as myocardial infarction (MI) and stroke, both affecting millions worldwide. T-cells and antibodies have been implicated in atherosclerosis. This thesis contains studies on CD4+ helper subsets and studies on antibodies against methylglyoxal-modified apolipoprotein B100 (MGO-ApoB100). In the prospective Malmö Diet and Cancer cohort we studied the relation of T helper 1 (Th1) and T helper 2 (Th2) cells to future cardiovacular events. We found that baseline-levels of Th2 cells, but not Th1 cells, were inversely associated with intima-media thickness in the cohort and future coronary events in women. In another cohort, the SUMMIT cohort, we found that type 2 diabetes patients with concomitant CVD were characterized by elevated levels of pro-inflammatory CD4+ T effector memory cells. Using a novel technique (the matrigel) for determining the immune responses in vivo, Th2 responses against human ApoB100 was characterized. In another study, genetic deletion of the signaling protein myeloid differentiation protein 88 (MyD88) in CD4+ T cells was found to reduce atherosclerosis. This reduction was associated with decreased production of the pro-inflammatory cytokine IL-17. In two separate studies, IgM antibodies against MGO-ApoB or MGO-ApoB-peptides were observed to be associated with reduced CVD. The mechanism mediating this protection against CVD remains to be clarified. This thesis presents and discusses aspects of immunity, which are interesting targets for pharmaceutical intervention. Various components of adaptive immunity may be useful as biomarkers for determining patients with increased risk of developing CVD.
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| 5. |
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| 6. |
- Engelbertsen, Daniel, et al.
(författare)
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High levels of IgM against methylglyoxal-modified apolipoprotein B100 is associated with less coronary artery calcification in patients with type 2 diabetes.
- 2012
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 271:1, s. 82-89
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Advanced glycation end products (AGE) have been implicated in diabetic vascular complications through activation of pro-inflammatory genes. AGE-modified proteins are also targeted by the immune system resulting in the generation of AGE-specific autoantibodies, but the association of these immune responses with diabetic vasculopathy remains to be fully elucidated. The aim of this study was to determine whether antibodies against apolipoprotein B100 modified by methylglyoxal (MGO-apoB100) are associated with coronary atherosclerosis in patients with type 2 diabetes. Methods. We measured antibodies against MGO-apoB100 in plasma from 497 type 2 diabetic patients without clinical signs of cardiovascular disease. Severity of coronary disease was assessed as coronary artery calcium (CAC) imaging. Immunoglobulin (Ig)M and IgG levels recognizing MGO-apoB100 were determined by enzyme-linked immunosorbent assay. Results. Anti-MGO-apoB100 IgM antibody levels were higher in subjects with a low to moderate CAC score (≤400 Agatston units) than in subjects with a high score (>400 Agatston units; 136.8 ± 4.4 vs. 101.6 ± 7.4 arbitrary units (AU), P < 0.0001) and in subjects demonstrating no progression of CAC during 30 months of follow-up (136.4 ± 5.7 vs. 113.9 ± 6.2 AU in subjects with progression, P < 0.0001). Subjects with a family history of premature myocardial infarction had lower levels of anti-MGO-apoB100 IgM. Female subjects had higher levels of anti-MGO-apoB100 antibodies and lower CAC than men. Accordingly, high levels of IgM against MGO-apoB100 are associated with less severe and a lower risk of progression of coronary disease in subjects with type 2 diabetes. Conclusions. Although conclusions regarding causal relationships based on epidemiological observations need to be made with caution, our findings suggest the possibility that anti-MGO-apoB100 IgM may be protective in diabetic vasculopathy.
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| 7. |
- Engelbertsen, Daniel, et al.
(författare)
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IL-1R and MyD88 signalling in CD4+ T cells promote Th17 immunity and atherosclerosis
- 2018
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 114:1, s. 180-187
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Tidskriftsartikel (refereegranskat)abstract
- The role of CD4+ T cells in atherosclerosis has been shown to be dependent on cytokine cues that regulate lineage commitment into mature T helper sub-sets. In this study, we tested the roles of IL-1R1 and MyD88 signalling in CD4+ T cells in atherosclerosis. Methods and results We transferred apoe-/-myd88\+/\+ or apoe-/-myd88-/- CD4+ T cells to T-A nd B-cell-deficient rag1-/-apoe-/- mice fed high fat diet. Mice given apoe-/-myd88-/- CD4+ T cells exhibited reduced atherosclerosis compared with mice given apoe-/-myd88\+/\+ CD4+ T cells. CD4+ T cells from apoe-/-myd88-/- produced less IL-17 but similar levels of IFN-c. Treatment of human CD4+ T cells with a MyD88 inhibitor inhibited IL-17 secretion in vitro. Transfer of il1r1-/- CD4+ T cells recapitulated the phenotype seen by transfer of myd88-/- CD4+ T cells with reduced lesion development and a reduction in Th17 and IL-17 production compared with wild type CD4+ T cell recipients. Relative collagen content of lesions was reduced in mice receiving il1r1-/- CD4+ T cells. Conclusion We demonstrate that both IL1R and MyD88 signalling in CD4+ T cells promote Th17 immunity, plaque growth and may regulate plaque collagen levels.
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| 8. |
- Engelbertsen, Daniel, et al.
(författare)
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IL-23R deficiency does not impact atherosclerotic plaque development in mice
- 2018
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Ingår i: Journal of the American Heart Association. - 2047-9980. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- Background--Interleukin-23 (IL-23) has been implicated in inflammatory and autoimmune diseases by skewing CD4+ T helper cells towards a pathogenic Th17 phenotype. In this study we investigated the presence of IL-23 receptor (IL-23R)-expressing cells in the atherosclerotic aorta and evaluated the effect of IL-23R deficiency on atherosclerosis development in mice. Methods and Results--We used heterozygous Ldlr-/-Il23reGFP/WT knock-in mice to identify IL-23R-expressing cells by flow cytometry and homozygous Ldlr-/-Il23reGFP/eGFP (Ldlr-/- Il23r-/-) mice to investigate the effect of lack of IL-23R in atherosclerosis. We demonstrate the presence of relatively rare IL-23R-expressing cells in lymphoid tissue and aorta (≈0.1-1% IL23R+ cells of all CD45+ leukocytes). After 10 weeks on a high-fat diet, production of IL-17, but not interferon-c, by CD4+ T cells and other lymphocytes was reduced in Ldlr-/- Il23r-/- compared with Ldlr-/-controls. However, Ldlr-/- and Ldlr-/-Il23r-/- mice had equivalent amounts of aortic sinus and descending aorta lesions. Adoptive transfer of IL-23R-deficient CD4+ T cells to lymphopenic Ldlr-/-Rag1-/- resulted in dramatically reduced IL-17-producing T cells but did not reduce atherosclerosis, compared with transfer of IL-23R-sufficient CD4+ T cells. Conclusions--These data demonstrate that loss of IL-23R does not affect development of experimental atherosclerosis in LDLrdeficient mice, despite a role for IL-23 in differentiation of IL-17-producing T cells.
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| 9. |
- Engelbertsen, Daniel, et al.
(författare)
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Increased Inflammation in Atherosclerotic Lesions of Diabetic Akita-LDLr(-/-) Mice Compared to Nondiabetic LDLr(-/-) Mice.
- 2012
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Ingår i: Experimental Diabetes Research. - : Hindawi Limited. - 1687-5214 .- 1687-5303. ; 2012:Nov.,28
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Tidskriftsartikel (refereegranskat)abstract
- Background. Diabetes is associated with increased cardiovascular disease, but the underlying cellular and molecular mechanisms are poorly understood. One proposed mechanism is that diabetes aggravates atherosclerosis by enhancing plaque inflammation. The Akita mouse has recently been adopted as a relevant model for microvascular complications of diabetes. Here we investigate the development of atherosclerosis and inflammation in vessels of Akita mice on LDLr(-/-) background. Methods and Results. Akita-LDLr(-/-) and LDLr(-/-) mice were fed high-fat diet from 6 to 24 weeks of age. Blood glucose levels were higher in both male and female Akita-LDLr(-/-) mice (137% and 70%, resp.). Male Akita-LDLr(-/-) mice had markedly increased plasma cholesterol and triglyceride levels, a three-fold increase in atherosclerosis, and enhanced accumulation of macrophages and T-cells in plaques. In contrast, female Akita-LDLr(-/-) mice demonstrated a modest 29% increase in plasma cholesterol and no significant increase in triglycerides, atherosclerosis, or inflammatory cells in lesions. Male Akita-LDLr(-/-) mice had increased levels of plasma IL-1β compared to nondiabetic mice, whereas no such difference was seen between female diabetic and nondiabetic mice. Conclusion. Akita-LDLr(-/-) mice display considerable gender differences in the development of diabetic atherosclerosis. In addition, the increased atherosclerosis in male Akita-LDLr(-/-) mice is associated with an increase in inflammatory cells in lesions.
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| 10. |
- Engelbertsen, Daniel, et al.
(författare)
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Increased lymphocyte activation and atherosclerosis in CD47-deficient mice
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- CD47, also known as integrin-associated protein (IAP), is a transmembrane protein with multiple biological functions including regulation of efferocytosis and leukocyte trafficking. In this study we investigated the effect of CD47-deficiency on atherosclerosis using a model of adeno-associated virus (AAV)-induced hypercholesterolemia. We observed increased plaque formation in CD47 null mice compared to wild-type controls. Loss of CD47 caused activation of dendritic cells, T cells and natural killer (NK) cells, indicating an important role for CD47 in regulating immunity. In particular, Cd47 deficiency increased the proportion of IFN-γ producing CD90+ NK cells. Treatment with depleting anti-NK1.1 monoclonal antibody (mAb), but not depleting anti-CD4/CD8 mAbs, equalized atherosclerotic burden, suggesting NK cells were involved in the enhanced disease in Cd47 deficient mice. Additional studies revealed that levels of CD90+ and IFN-γ+ NK cells were expanded in atherosclerotic aorta and that CD90+ NK cells produce more IFN-γ than CD90- NK cells. Finally, we demonstrate that anti-CD47 (MIAP410) causes splenomegaly and activation of DCs and T cells, without affecting NK cell activation. In summary, we demonstrate that loss of CD47 causes increased lymphocyte activation that results in increased atherosclerosis.
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