Interleukin-1 receptor accessory protein blockade limits the development of atherosclerosis and reduces plaque inflammation

The interleukin-1 receptor accessory protein (IL1RAP) is a co-receptor required for signalling through the IL-1, IL-33, and IL-36 receptors. Using a novel anti-IL1RAP-blocking antibody, we investigated the role of IL1RAP in atherosclerosis.Single-cell RNA sequencing data from human atherosclerotic plaques revealed the expression of IL1RAP and several IL1RAP-related cytokines and receptors, including IL1B and IL33. Histological analysis showed the presence of IL1RAP in both the plaque and adventitia, and flow cytometry of murine atherosclerotic aortas revealed IL1RAP expression on plaque leucocytes, including neutrophils and macrophages. High-cholesterol diet fed apolipoprotein E-deficient (Apoe-/-) mice were treated with a novel non-depleting IL1RAP-blocking antibody or isotype control for the last 6 weeks of diet. IL1RAP blockade in mice resulted in a 20% reduction in subvalvular plaque size and limited the accumulation of neutrophils and monocytes/macrophages in plaques and of T cells in adventitia, compared with control mice. Indicative of reduced plaque inflammation, the expression of several genes related to leucocyte recruitment, including Cxcl1 and Cxcl2, was reduced in brachiocephalic arteries of anti-IL1RAP-treated mice, and the expression of these chemokines in human plaques was mainly restricted to CD68+ myeloid cells. Furthermore, in vitro studies demonstrated that IL-1, IL-33, and IL-36 induced CXCL1 release from both macrophages and fibroblasts, which could be mitigated by IL1RAP blockade.Limiting IL1RAP-dependent cytokine signalling pathways in atherosclerotic mice reduces plaque burden and plaque inflammation, potentially by limiting plaque chemokine production.Biopharmaceutic

A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

Identification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined (T1D+T2D) GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 diabetic subjects (and 18,582 DKD cases). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, p=4.5×10-8) associated with 'microalbuminuria' in European T2D cases. However, no replication of this signal was observed in Asian subjects with T2D, or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously-reported DKD signals, except for those at UMOD and PRKAG2, both associated with 'EGFR'. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk-variant discovery for DKD.</p

Activation of immune responses against the basement membrane component collagen type IV does not affect the development of atherosclerosis in ApoE-deficient mice

AbstractOxidation of low-density lipoprotein (LDL) in the arterial extracellular matrix results in malondialdehyde (MDA)-modifications of surrounding matrix proteins. We have recently demonstrated an association between high levels of autoantibodies against MDA-modified collagen type IV and risk for development of myocardial infarction. Collagen type IV is an important component of the endothelial basement membrane and influences smooth muscle cell function. We hypothesized that immune responses against collagen type IV could contribute to vascular injury affecting the development of atherosclerosis. To investigate this possibility, we induced an antibody-response against collagen type IV in apolipoprotein E (Apo E)-deficient mice. Female ApoE−/− mice on C57BL/6 background were immunized with α1α2 type IV collagen chain peptides linked to the immune-enhancer PADRE, PADRE alone or PBS at 12 weeks of age with three subsequent booster injections before the mice were killed at 23 weeks of age. Immunization of PADRE alone induced autoantibodies against PADRE, increased IL-4 secretion from splenocytes and reduced SMC content in the subvalvular plaques. Immunization with peptides of α1α2 type IV collagen chains induced a strong IgG1antibody response against collagen type IV peptides without affecting the distribution of T cell populations, plasma cytokine or lipid levels. There were no differences in atherosclerotic plaque development between collagen α1α2(IV)-PADRE immunized mice and control mice. Our findings demonstrate that the presence of antibodies against the basement membrane component collagen type IV does not affect atherosclerosis development in ApoE−/− mice. This suggests that the association between autoantibodies against collagen type IV and risk for myocardial infarction found in humans does not reflect a pathogenic role of these autoantibodies.</jats:p

S100A9 blockade ameliorates cardiac dysfunction and reduces myocardial immune infiltration in experimental autoimmune myocarditis

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Swedish Heart and Lung Foundation and Swedish Research Council Background/Introduction Autoimmune myocarditis is characterized by non-ischemic inflammatory heart injury, leading to myocardial damage and impaired cardiac function. S100A9 is an inflammatory alarmin present in large amounts in neutrophils. The role of S100A9 as a potential treatment target in myocarditis has not been fully explored. Aim We sought to investigate the impact of S100A9 blockade in experimental autoimmune myocarditis and assess the effects of treatment on cardiac function and immune infiltration. Methods BALB/C mice were immunized with αMHC peptide emulsified in Complete Freunds Adjuvant at day 0 and day 7 to induce the disease. The water-soluble small-molecule S100A9 blocker ABR-238901 was given continuously in drinking water starting on day 7. Echocardiography was performed weekly from day 21 to day 42 (n=11/group). For flow cytometry analysis, mice were sacrificed at day 21 (n=10/group). Results S100A9 blockade improved left ventricular ejection fraction [52.33% vs 44.87% on day 42 (p&amp;lt;0.001)]. Cardiac output was significantly improved on day 21 (12.69 vs 11.05 mL/min, p&amp;lt;0.05). We found a significant reduction of inflammatory cardiac infiltrates at day 21, characterized by reduced number of macrophages (p&amp;lt;0.05), neutrophils (p&amp;lt;0.01) and CD4+ T cells (p&amp;lt;0.05). The cardiac draining lymph nodes contained fewer dendritic cells (p&amp;lt;0.01), T cells (p&amp;lt;0.05), as well as reduced numbers of inflammatory CD4+ cells producing IL-17 (p&amp;lt;0.05). Conclusion Therapeutic S100A9 blockade inhibits inflammatory cardiac infiltration and improves cardiac function in experimental autoimmune myocarditis. Our findings highlight the important role of S100A9 in the pathogenesis of myocarditis and identify S100A9 blockade as a possible novel therapeutic avenue. </jats:sec

Activation of immune responses against the basement membrane component collagen type IV does not affect the development of atherosclerosis in ApoE-deficient mice

Oxidation of low-density lipoprotein (LDL) in the arterial extracellular matrix results in malondialdehyde (MDA)-modifications of surrounding matrix proteins. We have recently demonstrated an association between high levels of autoantibodies against MDA-modified collagen type IV and risk for development of myocardial infarction. Collagen type IV is an important component of the endothelial basement membrane and influences smooth muscle cell function. We hypothesized that immune responses against collagen type IV could contribute to vascular injury affecting the development of atherosclerosis. To investigate this possibility, we induced an antibody-response against collagen type IV in apolipoprotein E (Apo E)-deficient mice. Female ApoE −/− mice on C57BL/6 background were immunized with α1α2 type IV collagen chain peptides linked to the immune-enhancer PADRE, PADRE alone or PBS at 12 weeks of age with three subsequent booster injections before the mice were killed at 23 weeks of age. Immunization of PADRE alone induced autoantibodies against PADRE, increased IL-4 secretion from splenocytes and reduced SMC content in the subvalvular plaques. Immunization with peptides of α1α2 type IV collagen chains induced a strong IgG1antibody response against collagen type IV peptides without affecting the distribution of T cell populations, plasma cytokine or lipid levels. There were no differences in atherosclerotic plaque development between collagen α1α2(IV)-PADRE immunized mice and control mice. Our findings demonstrate that the presence of antibodies against the basement membrane component collagen type IV does not affect atherosclerosis development in ApoE −/− mice. This suggests that the association between autoantibodies against collagen type IV and risk for myocardial infarction found in humans does not reflect a pathogenic role of these autoantibodies

High levels of IgM against methylglyoxal-modified apolipoprotein B100 are associated with less coronary artery calcification in patients with type 2 diabetes

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; 136.8 +/- 4.4 vs. 101.6 +/- 7.4 arbitrary units (AU), P &lt;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 &lt;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.</p

Expansion of CD25+ Innate Lymphoid Cells Reduces Atherosclerosis

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