1. |
- Bosmans, Laura A., et al.
(author)
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Myeloid CD40 deficiency reduces atherosclerosis by impairing macrophages’ transition into a pro-inflammatory state
- 2023
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 119:5, s. 1146-1160
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Journal article (peer-reviewed)abstract
- Aims CD40 and its ligand, CD40L, play a critical role in driving atherosclerotic plaque development. Disrupted CD40-signalling reduces experimental atherosclerosis and induces a favourable stable plaque phenotype. We recently showed that small molecule-based inhibition of CD40-tumour necrosis factor receptor associated factor-6 interactions attenuates atherosclerosis in hyperlipidaemic mice via macrophage-driven mechanisms. The present study aims to detail the function of myeloid CD40 in atherosclerosis using myeloid-specific CD40-deficient mice. Method and Cd40flox/flox and LysM-cre Cd40flox/flox mice on an Apoe−/− background were generated (CD40wt and CD40mac−/− , respect-Results ively). Atherosclerotic lesion size, as well as plaque macrophage content, was reduced in CD40mac−/− compared to CD40wt mice, and their plaques displayed a reduction in necrotic core size. Transcriptomics analysis of the CD40mac−/− atherosclerotic aorta revealed downregulated pathways of immune pathways and inflammatory responses. Loss of CD40 in macrophages changed the representation of aortic macrophage subsets. Mass cytometry analysis revealed a higher content of a subset of alternative or resident-like CD206+CD209b− macrophages in the atherosclerotic aorta of CD40mac−/− compared to CD40wt mice. RNA-sequencing of bone marrow-derived macrophages of CD40mac−/− mice demonstrated upregulation of genes associated with alternatively activated macrophages (including Folr2, Thbs1, Sdc1, and Tns1). Conclusions We here show that absence of CD40 signalling in myeloid cells reduces atherosclerosis and limits systemic inflammation by preventing a shift in macrophage polarization towards pro-inflammatory states. Our study confirms the merit of macrophage-targeted inhibition of CD40 as a valuable therapeutic strategy to combat atherosclerosis.
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2. |
- Shami, Annelie, et al.
(author)
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Glucocorticoid-induced tumour necrosis factor receptor family-related protein (GITR) drives atherosclerosis in mice and is associated with an unstable plaque phenotype and cerebrovascular events in humans
- 2020
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In: European Heart Journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 41:31, s. 2938-2948
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Journal article (peer-reviewed)abstract
- AIMS: GITR-a co-stimulatory immune checkpoint protein-is known for both its activating and regulating effects on T-cells. As atherosclerosis bears features of chronic inflammation and autoimmunity, we investigated the relevance of GITR in cardiovascular disease (CVD). METHODS AND RESULTS: GITR expression was elevated in carotid endarterectomy specimens obtained from patients with cerebrovascular events (n = 100) compared to asymptomatic patients (n = 93) and correlated with parameters of plaque vulnerability, including plaque macrophage, lipid and glycophorin A content, and levels of interleukin (IL)-6, IL-12, and C-C-chemokine ligand 2. Soluble GITR levels were elevated in plasma from subjects with CVD compared to healthy controls. Plaque area in 28-week-old Gitr-/-Apoe-/- mice was reduced, and plaques had a favourable phenotype with less macrophages, a smaller necrotic core and a thicker fibrous cap. GITR deficiency did not affect the lymphoid population. RNA sequencing of Gitr-/-Apoe-/- and Apoe-/- monocytes and macrophages revealed altered pathways of cell migration, activation, and mitochondrial function. Indeed, Gitr-/-Apoe-/- monocytes displayed decreased integrin levels, reduced recruitment to endothelium, and produced less reactive oxygen species. Likewise, GITR-deficient macrophages produced less cytokines and had a reduced migratory capacity. CONCLUSION: Our data reveal a novel role for the immune checkpoint GITR in driving myeloid cell recruitment and activation in atherosclerosis, thereby inducing plaque growth and vulnerability. In humans, elevated GITR expression in carotid plaques is associated with a vulnerable plaque phenotype and adverse cerebrovascular events. GITR has the potential to become a novel therapeutic target in atherosclerosis as it reduces myeloid cell recruitment to the arterial wall and impedes atherosclerosis progression.
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3. |
- Strom, Asa C., et al.
(author)
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B regulatory cells are increased in hypercholesterolaemic mice and protect from lesion development via IL-10
- 2015
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In: Thrombosis and Haemostasis. - 0340-6245. ; 114:4, s. 835-847
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Journal article (peer-reviewed)abstract
- Whilst innate B1-B cells are atheroprotective, adaptive B2-B cells are considered pro-atherogenic. Different subsets of B regulatory cells (B-reg) have been described. In experimental arthritis and lupus-like disease, B-reg are contained within the CD21(hi)CD23(hi)CD24(hi) B cell pool The existence and role of B-reg in vascular disease is not known. We sought to investigate the existence, identity and location of B-reg in vascular disease. The representation of B2-B cell subsets in the spleens and lymph nodes (LNs) of Apolipoprotein E-/- (ApoE(-/-)) mice compared to controls was characterised by flow cytometry. Additionally, we utilised a model of neointima formation based on the placement of a perivascular collar around the carotid artery in ApoE(-/-) mice to ascertain whether B cells and B cell subsets confer protection against lesion development. Adoptive transfer of B cells was performed from wild type or genetically modified mice. We showed that CD21(hi)CD23(hi)CD24(hi) B cells are unexpectedly increased in the draining LNs of ApoE(-/-) mice. Adoptive transfer of LN-derived B2-B cells or purified CD21(hi)CD23(hi)CD24(hi) B cells to syngeneic mice reduced lesion size and inflammation without changing serum cholesterol levels. Follicular B2-B cells did not confer protection. IL-10 blockade or transfer of IL10-deficient B cells prevented LN-derived B cell-mediated protection. This is the first identification of a specific LN-derived B2-B-reg subset that confers IL-10 mediated protection from neointima formation. This may open the way for immune modulatory approaches in cardiovascular disease.
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4. |
- De Winther, Menno P.J., et al.
(author)
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Translational opportunities of single-cell biology in atherosclerosis
- 2023
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In: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 44:14, s. 1216-1230
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Research review (peer-reviewed)abstract
- The advent of single-cell biology opens a new chapter for understanding human biological processes and for diagnosing, monitoring, and treating disease. This revolution now reaches the field of cardiovascular disease (CVD). New technologies to interrogate CVD samples at single-cell resolution are allowing the identification of novel cell communities that are important in shaping disease development and direct towards new therapeutic strategies. These approaches have begun to revolutionize atherosclerosis pathology and redraw our understanding of disease development. This review discusses the state-of-the-art of single-cell analysis of atherosclerotic plaques, with a particular focus on human lesions, and presents the current resolution of cellular subpopulations and their heterogeneity and plasticity in relation to clinically relevant features. Opportunities and pitfalls of current technologies as well as the clinical impact of single-cell technologies in CVD patient care are highlighted, advocating for multidisciplinary and international collaborative efforts to join the cellular dots of CVD.
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5. |
- Dib, Lea, et al.
(author)
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Lipid-associated macrophages transition to an inflammatory state in human atherosclerosis, increasing the risk of cerebrovascular complications
- 2023
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In: Nature Cardiovascular Research. - 2731-0590. ; 2:7, s. 656-672
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Journal article (peer-reviewed)abstract
- The immune system is integral to cardiovascular health and disease. Targeting inflammation ameliorates adverse cardiovascular outcomes. Atherosclerosis, a major underlying cause of cardiovascular disease, is conceptualized as lipid-driven inflammation in which macrophages play a nonredundant role. However, evidence emerging so far from single-cell atlases suggests a dichotomy between lipid-associated and inflammatory macrophage states. Here, we present an inclusive reference atlas of human intraplaque immune cell communities. Combining single-cell RNA sequencing (scRNA-seq) of human surgical carotid endarterectomies in a discovery cohort with bulk RNA-seq and immunohistochemistry in a validation cohort (the Carotid Plaque Imaging Project), we reveal the existence of PLIN2hi/TREM1hi macrophages as a Toll-like receptor (TLR)-dependent inflammatory lipid-associated macrophage state linked to cerebrovascular events. Our study shifts the current paradigm of lipid-driven inflammation by providing biological evidence for a pathogenic macrophage transition to an inflammatory lipid-associated phenotype and for its targeting as a new treatment strategy for cardiovascular disease.
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6. |
- Edsfeldt, Andreas, et al.
(author)
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Interferon regulatory factor-5-dependent CD11c+ macrophages contribute to the formation of rupture-prone atherosclerotic plaques
- 2022
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In: European Heart Journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 43:19, s. 1864-1877
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Journal article (peer-reviewed)abstract
- AIMS: Inflammation is a key factor in atherosclerosis. The transcription factor interferon regulatory factor-5 (IRF5) drives macrophages towards a pro-inflammatory state. We investigated the role of IRF5 in human atherosclerosis and plaque stability.METHODS AND RESULTS: Bulk RNA sequencing from the Carotid Plaque Imaging Project biobank were used to mine associations between major macrophage associated genes and transcription factors and human symptomatic carotid disease. Immunohistochemistry, proximity extension assays, and Helios cytometry by time of flight (CyTOF) were used for validation. The effect of IRF5 deficiency on carotid plaque phenotype and rupture in ApoE-/- mice was studied in an inducible model of plaque rupture. Interferon regulatory factor-5 and ITGAX/CD11c were identified as the macrophage associated genes with the strongest associations with symptomatic carotid disease. Expression of IRF5 and ITGAX/CD11c correlated with the vulnerability index, pro-inflammatory plaque cytokine levels, necrotic core area, and with each other. Macrophages were the predominant CD11c-expressing immune cells in the plaque by CyTOF and immunohistochemistry. Interferon regulatory factor-5 immunopositive areas were predominantly found within CD11c+ areas with a predilection for the shoulder region, the area of the human plaque most prone to rupture. Accordingly, an inducible plaque rupture model of ApoE-/-Irf5-/- mice had significantly lower frequencies of carotid plaque ruptures, smaller necrotic cores, and less CD11c+ macrophages than their IRF5-competent counterparts.CONCLUSION: Using complementary evidence from data from human carotid endarterectomies and a murine model of inducible rupture of carotid artery plaque in IRF5-deficient mice, we demonstrate a mechanistic link between the pro-inflammatory transcription factor IRF5, macrophage phenotype, plaque inflammation, and its vulnerability to rupture.KEY QUESTION: The transcription factor interferon regulatory factor-5 (IRF5) is a master regulator of macrophage activation that has been shown to have a role in murine atherogenesis. Its role in human atherosclerosis and its complications is unknown.KEY FINDING: Interferon regulatory factor-5 is linked to plaque vulnerability and symptoms in human carotid endarterectomies. In a murine model of inducible carotid artery plaque rupture, IRF5 drives plaque rupture. Interferon regulatory factor-5 modulates macrophage phenotype and it colocalises with CD11c+ macrophages at the plaque shoulder.TAKE-HOME MESSAGE: We demonstrate a mechanistic link between the IRF5, plaque macrophages, and plaque vulnerability to rupture. Interferon regulatory factor-5 is a potential candidate therapeutic target in human atherosclerosis.
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7. |
- Forteza, Maria J., et al.
(author)
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Pyruvate dehydrogenase kinase regulates vascular inflammation in atherosclerosis and increases cardiovascular risk
- 2023
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 119:7, s. 1524-1536
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Journal article (peer-reviewed)abstract
- Recent studies have revealed a close connection between cellular metabolism and the chronic inflammatory process of atherosclerosis. While the link between systemic metabolism and atherosclerosis is well established, the implications of altered metabolism in the artery wall are less understood. Pyruvate dehydrogenase kinase (PDK)-dependent inhibition of pyruvate dehydrogenase (PDH) has been identified as a major metabolic step regulating inflammation. Whether the PDK/PDH axis plays a role in vascular inflammation and atherosclerotic cardiovascular disease remains unclear. Methods and results Gene profiling of human atherosclerotic plaques revealed a strong correlation between PDK1 and PDK4 transcript levels and the expression of pro-inflammatory and destabilizing genes. Remarkably, the PDK1 and PDK4 expression correlated with a more vulnerable plaque phenotype, and PDK1 expression was found to predict future major adverse cardiovascular events. Using the small-molecule PDK inhibitor dichloroacetate (DCA) that restores arterial PDH activity, we demonstrated that the PDK/PDH axis is a major immunometabolic pathway, regulating immune cell polarization, plaque development, and fibrous cap formation in Apoe−/− mice. Surprisingly, we discovered that DCA regulates succinate release and mitigates its GPR91-dependent signals promoting NLRP3 inflammasome activation and IL-1β secretion by macrophages in the plaque. Conclusions We have demonstrated for the first time that the PDK/PDH axis is associated with vascular inflammation in humans and particularly that the PDK1 isozyme is associated with more severe disease and could predict secondary cardiovascular events. Moreover, we demonstrate that targeting the PDK/PDH axis with DCA skews the immune system, inhibits vascular inflammation and atherogenesis, and promotes plaque stability features in Apoe−/− mice. These results point toward a promising treatment to combat atherosclerosis.
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8. |
- Masuda, Takahiro, et al.
(author)
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Specification of CNS macrophage subsets occurs postnatally in defined niches
- 2022
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In: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 604:7907, s. 740-
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Journal article (peer-reviewed)abstract
- All tissue-resident macrophages of the central nervous system (CNS)-including parenchymal microglia, as well as CNS-associated macrophages (CAMs(1)) such as meningeal and perivascular macrophages(2-)(7)-are part of the CNS endogenous innate immune system that acts as the first line of defence during infections or trauma(2,8-10). It has been suggested that microglia and all subsets of CAMs are derived from prenatal cellular sources in the yolk sac that were defined as early erythromyeloid progenitors(11-15). However, the precise ontogenetic relationships, the underlying transcriptional programs and the molecular signals that drive the development of distinct CAM subsets in situ are poorly understood. Here we show, using fate-mapping systems, single-cell profiling and cell-specific mutants, that only meningeal macrophages and microglia share a common prenatal progenitor. By contrast, perivascular macrophages originate from perinatal meningeal macrophages only after birth in an integrin-dependent manner. The establishment of perivascular macrophages critically requires the presence of arterial vascular smooth muscle cells. Together, our data reveal a precisely timed process in distinct anatomical niches for the establishment of macrophage subsets in the CNS.
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9. |
- Seneviratne, Anusha N., et al.
(author)
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Interferon Regulatory Factor 5 Controls Necrotic Core Formation in Atherosclerotic Lesions by Impairing Efferocytosis
- 2017
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In: Circulation. - 0009-7322. ; 136:5, s. 1140-1154
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Journal article (peer-reviewed)abstract
- BACKGROUND—: Myeloid cells are central to atherosclerotic lesion development and vulnerable plaque formation. Impaired ability of arterial phagocytes to uptake apoptotic cells (efferocytosis), promotes lesion growth and establishment of a necrotic core. The transcription factor Interferon Regulatory Factor (IRF)-5 is an important modulator of myeloid function and programming. We sought to investigate whether IRF5 affects the formation and phenotype of atherosclerotic lesions. METHODS—: We investigated the role of IRF5 in atherosclerosis in two complementary models. First, atherosclerotic lesion development in hyperlipidemic apolipoprotein E-deficient (ApoE) mice and ApoE mice with a genetic deletion of IRF5 (ApoEIrf5) was compared then lesion development was assessed in a model of shear stress modulated vulnerable plaque formation. RESULTS—: Both lesion size and necrotic core size were significantly reduced in ApoEIrf5 mice compared to IRF5 competent ApoE mice. Necrotic core size was also reduced in the model of shear stress modulated vulnerable plaque formation. A significant loss of CD11c macrophages was evident in ApoEIrf5 mice in the aorta, draining lymph nodes and in bone marrow cell cultures, indicating that IRF5 maintains CD11c macrophages in atherosclerosis. Moreover, we revealed that the CD11c gene is a direct target of IRF5 in macrophages. In the absence of IRF5, CD11c macrophages displayed a significant increase in expression of the efferocytosis regulating integrin-β3 and its ligand milk fat globule-EGF factor 8 protein (Mfge8) and enhanced efferocytosis in vitro and in situ. CONCLUSIONS—: IRF5 is detrimental in atherosclerosis by promoting the maintenance of pro-inflammatory CD11c+ macrophages within lesions and controlling the expansion of the necrotic core by impairing efferocytosis.Circulation is published on behalf of the American Heart Association, Inc., by Wolters Kluwer Health, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited.
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10. |
- Szatmari, Peter, et al.
(author)
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Mapping autism risk loci using genetic linkage and chromosomal rearrangements.
- 2007
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:3, s. 319-328
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Journal article (peer-reviewed)abstract
- Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
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