Leukemia inhibitory factor receptor inhibition by EC359 reduces atherosclerotic stenosis grade in Ldlr mice.

Cytokines are involved in all stages of atherosclerosis, generally contributing to disease progression. Previously, members of the Interleukin (IL)-6 cytokine family, such as IL-6, oncostatin M, and cardiotrophin-1, have been extensively studied in atherosclerosis. However, the role of leukemia inhibitory factor (LIF), member of the IL-6 family, and its receptor (LIFR), remains to be further elucidated.

Sexual dimorphism in atherosclerotic plaques of aged Ldlr mice.

Background: Atherosclerosis, the main underlying pathology of cardiovascular disease, is a chronic inflammatory disease characterized by lipid accumulation and immune cell responses in the vascular wall, resulting in plaque formation. It is well-known that atherosclerosis prevalence and manifestation vary by sex. However, sexual dimorphism in the immune landscape of atherosclerotic plaques has up to date not been studied at high-resolution.

Immunoproteasomal Inhibition With ONX-0914 Attenuates Atherosclerosis and Reduces White Adipose Tissue Mass and Metabolic Syndrome in Mice.

Background: Atherosclerosis is the major underlying pathology of cardiovascular disease and is driven by dyslipidemia and inflammation. Inhibition of the immunoproteasome, a proteasome variant that is predominantly expressed by immune cells and plays an important role in antigen presentation, has been shown to have immunosuppressive effects.

Methods: We assessed the effect of ONX-0914, an inhibitor of the immunoproteasomal catalytic subunits LMP7 (proteasome subunit β5i/large multifunctional peptidase 7) and LMP2 (proteasome subunit β1i/large multifunctional peptidase 2), on atherosclerosis and metabolism in LDLr and APOE*3-Leiden.

Resident Memory T Cells in the Atherosclerotic Lesion Associate With Reduced Macrophage Content and Increased Lesion Stability.

Background: Tissue resident memory T (T) cells are a T-cell subset that resides at the site of prior antigen recognition to protect the body against reoccurring encounters. Besides their protective function, T cells have also been implicated in inflammatory disorders. T cells are characterized by the expression of CD69 and transcription factors Hobit (homolog of Blimp-1 [B lymphocyte-induced maturation protein 1] in T cells) and Blimp-1.

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

Aims: 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.

Methods And Results: 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.

Virus-Associated CD8 T-Cells Are Not Activated Through Antigen-Mediated Interaction Inside Atherosclerotic Lesions.

Introduction: Viral infections have been associated with the progression of atherosclerosis and CD8 T-cells directed against common viruses, such as influenza, Epstein-Barr virus, and cytomegalovirus, have been detected inside human atherosclerotic lesions. These virus-specific CD8 T-cells have been hypothesized to contribute to the development of atherosclerosis; however, whether they affect disease progression directly remains unclear. In this study, we aimed to characterize the activation status of virus-specific CD8 T-cells in the atherosclerotic lesion.

Single-cell profiling reveals age-associated immunity in atherosclerosis.

Aims: Aging is a dominant driver of atherosclerosis and induces a series of immunological alterations, called immunosenescence. Given the demographic shift towards elderly, elucidating the unknown impact of aging on the immunological landscape in atherosclerosis is highly relevant. While the young Western diet-fed Ldlr-deficient (Ldlr-/-) mouse is a widely used model to study atherosclerosis, it does not reflect the gradual plaque progression in the context of an aging immune system as occurs in humans.

Bruton's Tyrosine Kinase inhibition by Acalabrutinib does not affect early or advanced atherosclerotic plaque size and morphology in Ldlr mice.

Atherosclerosis is characterized by the accumulation of lipids and immune cells, including mast cells and B cells, in the arterial wall. Mast cells contribute to atherosclerotic plaque growth and destabilization upon active degranulation. The FcεRI-IgE pathway is the most prominent mast cell activation route.

Female gene networks are expressed in myofibroblast-like smooth muscle cells in vulnerable atherosclerotic plaques.

Women presenting with coronary artery disease (CAD) more often present with fibrous atherosclerotic plaques, which are currently understudied. Phenotypically modulated smooth muscle cells (SMCs) contribute to atherosclerosis in women. How these phenotypically modulated SMCs shape female versus male plaques is unknown.

Single-cell T cell receptor sequencing of paired human atherosclerotic plaques and blood reveals autoimmune-like features of expanded effector T cells.

Atherosclerosis is a lipid-driven chronic inflammatory disease; however, whether it can be classified as an autoimmune disease remains unclear. In this study, we applied single-cell T cell receptor seqencing (scTCR-seq) on human carotid artery plaques and matched peripheral blood mononuclear cell samples to assess the extent of TCR clonality and antigen-specific activation within the various T cell subsets. We observed the highest degree of plaque-specific clonal expansion in effector CD4 T cells, and these clonally expanded T cells expressed genes such as , and , indicative of recent TCR engagement, suggesting antigen-specific stimulation.

Blockade of the BLT1-LTB axis does not affect mast cell migration towards advanced atherosclerotic lesions in LDLr mice.

Mast cells have been associated with the progression and destabilization of advanced atherosclerotic plaques. Reducing intraplaque mast cell accumulation upon atherosclerosis progression could be a potent therapeutic strategy to limit plaque destabilization. Leukotriene B (LTB) has been reported to induce mast cell chemotaxis in vitro.

Intersecting single-cell transcriptomics and genome-wide association studies identifies crucial cell populations and candidate genes for atherosclerosis.

Aims: Genome-wide association studies (GWASs) have discovered hundreds of common genetic variants for atherosclerotic disease and cardiovascular risk factors. The translation of susceptibility loci into biological mechanisms and targets for drug discovery remains challenging. Intersecting genetic and gene expression data has led to the identification of candidate genes.

Microanatomy of the Human Atherosclerotic Plaque by Single-Cell Transcriptomics.

Rationale: Atherosclerotic lesions are known for their cellular heterogeneity, yet the molecular complexity within the cells of human plaques has not been fully assessed.

Objective: Using single-cell transcriptomics and chromatin accessibility, we gained a better understanding of the pathophysiology underlying human atherosclerosis.

Methods And Results: We performed single-cell RNA and single-cell ATAC sequencing on human carotid atherosclerotic plaques to define the cells at play and determine their transcriptomic and epigenomic characteristics.

VLDL/LDL serves as the primary source of cholesterol in the adrenal glucocorticoid response to food deprivation.

The contribution of individual lipoprotein species to the generation of the adrenal cholesterol pool used for the synthesis of anti-inflammatory glucocorticoid species remains unknown. Here we examined the impact of specific lowering of very low-density lipoprotein (VLDL) and low-density (LDL) levels on adrenal cholesterol and glucocorticoid homeostasis. Hereto, lethally-irradiated hypercholesterolemic apolipoprotein E (APOE) knockout mice received APOE-containing bone marrow from wild-type mice (n = 6) or APOE knockout control bone marrow (n = 10) and were subsequently fed a regular chow diet.

Increased lymphocyte activation and atherosclerosis in CD47-deficient mice.

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.

B- and T-lymphocyte attenuator stimulation protects against atherosclerosis by regulating follicular B cells.

Aims: The immune system is strongly involved in atherosclerosis and immune regulation generally leads to attenuated atherosclerosis. B- and T-lymphocyte attenuator (BTLA) is a novel co-receptor that negatively regulates the activation of B and T cells; however, there have been no reports of BTLA and its function in atherosclerosis or cardiovascular disease (CVD). We aimed to assess the dominant BTLA expressing leucocyte in CVD patients and to investigate whether BTLA has a functional role in experimental atherosclerosis.

Flow Cytometry-Based Characterization of Mast Cells in Human Atherosclerosis.

The presence of mast cells in human atherosclerotic plaques has been associated with adverse cardiovascular events. Mast cell activation, through the classical antigen sensitized-IgE binding to their characteristic Fcε-receptor, causes the release of their cytoplasmic granules. These granules are filled with neutral proteases such as tryptase, but also with histamine and pro-inflammatory mediators.

Elimination of adrenocortical apolipoprotein E production does not impact glucocorticoid output in wild-type mice.

Apolipoprotein E (APOE) deficient mice exhibit unexplained hypercorticosteronemia. Given that APOE is also produced locally within the adrenals, we evaluated the effect of adrenal-specific APOE deficiency on the glucocorticoid function. Hereto, one adrenal containing or lacking APOE was transplanted into adrenalectomized wild-type mice.

IL-23R Deficiency Does Not Impact Atherosclerotic Plaque Development in Mice.

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 knock-in mice to identify IL-23R-expressing cells by flow cytometry and homozygous ( ) mice to investigate the effect of lack of IL-23R in atherosclerosis.