TREM2 protects from atherosclerosis by limiting necrotic core formation.

Atherosclerosis is a chronic disease of the vascular wall driven by lipid accumulation and inflammation in the intimal layer of arteries, and its main complications, myocardial infarction and stroke, are the leading cause of mortality worldwide [1], [2]. Recent studies have identified Triggering receptor expressed on myeloid cells 2 (TREM2), a lipid-sensing receptor regulating myeloid cell functions [3], to be highly expressed in macrophage foam cells in experimental and human atherosclerosis [4]. However, the role of TREM2 in atherosclerosis is not fully known.

Marginal zone B cells produce 'natural' atheroprotective IgM antibodies in a T cell-dependent manner.

Aims: The adaptive immune response plays an important role in atherosclerosis. In response to a high-fat/high-cholesterol (HF/HC) diet, marginal zone B (MZB) cells activate an atheroprotective programme by regulating the differentiation and accumulation of 'poorly differentiated' T follicular helper (Tfh) cells. On the other hand, Tfh cells activate the germinal centre response, which promotes atherosclerosis through the production of class-switched high-affinity antibodies.

Cell-autonomous regulation of complement C3 by factor H limits macrophage efferocytosis and exacerbates atherosclerosis.

Complement factor H (CFH) negatively regulates consumption of complement component 3 (C3), thereby restricting complement activation. Genetic variants in CFH predispose to chronic inflammatory disease. Here, we examined the impact of CFH on atherosclerosis development.

High immunoglobulin-M levels to oxidation-specific epitopes are associated with lower risk of acute myocardial infarction.

Immunoglobulin M (IgM) autoantibodies to oxidation-specific epitopes (OSEs) can be present at birth and protect against atherosclerosis in experimental models. This study sought to determine whether high titers of IgM titers to OSE (IgM OSE) are associated with a lower risk of acute myocardial infarction (AMI) in humans. IgM to malondialdehyde (MDA)-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and a peptide mimotope of MDA were measured within 24 h of first AMI in 4,559 patients and 4,617 age- and sex-matched controls in the Pakistan Risk of Myocardial Infarction Study.

Increasing test specificity without impairing sensitivity: lessons learned from SARS-CoV-2 serology.

Background: Serological tests are widely used in various medical disciplines for diagnostic and monitoring purposes. Unfortunately, the sensitivity and specificity of test systems are often poor, leaving room for false-positive and false-negative results. However, conventional methods were used to increase specificity and decrease sensitivity and vice versa.

Association of Lipoproteins with Neutrophil Extracellular Traps in Patients with Abdominal Aortic Aneurysm.

Neutrophil extracellular traps (NETs) are DNA-protein structures released by neutrophils in response to various stimuli, including oxidized, low-density lipoprotein (oxLDL). Accumulating evidence suggests a role for NETs in the pathogenesis of abdominal aortic aneurysm (AAA). In this study, we investigated the potential association of lipoprotein particles and NETs in AAA in comparison to non-AAA control groups.

APRIL limits atherosclerosis by binding to heparan sulfate proteoglycans.

Atherosclerotic cardiovascular disease causes heart attacks and strokes, which are the leading causes of mortality worldwide. The formation of atherosclerotic plaques is initiated when low-density lipoproteins bind to heparan-sulfate proteoglycans (HSPGs) and become trapped in the subendothelial space of large and medium size arteries, which leads to chronic inflammation and remodelling of the artery wall. A proliferation-inducing ligand (APRIL) is a cytokine that binds to HSPGs, but the physiology of this interaction is largely unknown.

SIRPα on Mouse B1 Cells Restricts Lymphoid Tissue Migration and Natural Antibody Production.

The inhibitory immunoreceptor SIRPα is expressed on myeloid and neuronal cells and interacts with the broadly expressed CD47. CD47-SIRPα interactions form an innate immune checkpoint and its targeting has shown promising results in cancer patients. Here, we report expression of SIRPα on B1 lymphocytes, a subpopulation of murine B cells responsible for the production of natural antibodies.

The Effect of a 13-Valent Conjugate Pneumococcal Vaccine on Circulating Antibodies Against Oxidized LDL and Phosphorylcholine in Man, A Randomized Placebo-Controlled Clinical Trial.

In mice vaccination with results in an increase in anti-oxLDL IgM antibodies due to mimicry of anti-phosphorylcholine (present in the cell wall of ) and anti-oxLDL IgM. In this study we investigated the human translation of this molecular mimicry by vaccination against using the Prevenar-13 vaccine. Twenty-four healthy male volunteers were vaccinated with Prevenar-13, either three times, twice or once in a double-blind, placebo-controlled, randomized single center clinical study.

Impaired Autophagy in CD11b Dendritic Cells Expands CD4 Regulatory T Cells and Limits Atherosclerosis in Mice.

Rationale: Atherosclerosis is a chronic inflammatory disease. Recent studies have shown that dysfunctional autophagy in endothelial cells, smooth muscle cells, and macrophages, plays a detrimental role during atherogenesis, leading to the suggestion that autophagy-stimulating approaches may provide benefit.

Objective: Dendritic cells (DCs) are at the crossroad of innate and adaptive immune responses and profoundly modulate the development of atherosclerosis.

Complement Factor H Modulates Splenic B Cell Development and Limits Autoantibody Production.

Complement factor H (CFH) has a pivotal role in regulating alternative complement activation through its ability to inhibit the cleavage of the central complement component C3, which links innate and humoral immunity. However, insights into the role of CFH in B cell biology are limited. Here, we demonstrate that deficiency of CFH in mice leads to altered splenic B cell development characterized by the accumulation of marginal zone (MZ) B cells.

B Cell-Activating Factor Neutralization Aggravates Atherosclerosis.

Background: Atherosclerotic cardiovascular disease (heart attacks and strokes) is the major cause of death globally and is caused by the buildup of a plaque in the arterial wall. Genomic data showed that the B cell-activating factor (BAFF) receptor pathway, which is specifically essential for the survival of conventional B lymphocytes (B-2 cells), is a key driver of coronary heart disease. Deletion or antibody-mediated blockade of BAFF receptor ablates B-2 cells and decreases experimental atherosclerosis.

Deletion of IRF8 (Interferon Regulatory Factor 8)-Dependent Dendritic Cells Abrogates Proatherogenic Adaptive Immunity.

Rationale: Despite an established role for adaptive immune responses in atherosclerosis, the contribution of dendritic cells (DCs) and their various subsets is still poorly understood.

Objective: Here, we address the role of IRF8 (interferon regulatory factor 8)-dependent DCs (lymphoid CD8α and their developmentally related nonlymphoid CD103 DCs) in the induction of proatherogenic immune responses during high fat feeding.

Methods And Results: Using a fate-mapping technique to track DCs originating from a DNGR1 (dendritic cell natural killer lectin group receptor 1) precursor ( mice), we first show that YFPCD11cMHCII (major histocompatibility complex class II) DCs are present in the atherosclerotic aorta of low-density lipoprotein receptor-deficient () mice and are CD11bCD103IRF8.

Increased Plasma IgE Accelerate Atherosclerosis in Secreted IgM Deficiency.

Rationale: Deficiency of secreted IgM (sIgM) accelerates atherosclerosis in Ldlrmice. Several atheroprotective effects of increased levels of IgM antibodies have been suggested, including preventing inflammation induced by oxidized low-density lipoprotein and promoting apoptotic cell clearance. However, the mechanisms by which the lack of sIgM promotes lesion formation remain unknown.

Low levels of IgM antibodies recognizing oxidation-specific epitopes are associated with human non-alcoholic fatty liver disease.

Background: Lipid oxidation of membrane phospholipids is accompanied by the formation of oxidation-specific epitopes (OSE). These epitopes are recognized by specific antibodies and represent danger-associated molecular patterns that are generated during chronic inflammatory processes. In a murine model for hepatic inflammation during non-alcoholic fatty liver disease (NAFLD), increased antibody levels targeting OSE were found to be protective.

Sialic Acid-Binding Immunoglobulin-like Lectin G Promotes Atherosclerosis and Liver Inflammation by Suppressing the Protective Functions of B-1 Cells.

Atherosclerosis is initiated and sustained by hypercholesterolemia, which results in the generation of oxidized LDL (OxLDL) and other metabolic byproducts that trigger inflammation. Specific immune responses have been shown to modulate the inflammatory response during atherogenesis. The sialic acid-binding immunoglobulin-like lectin G (Siglec-G) is a negative regulator of the functions of several immune cells, including myeloid cells and B-1 cells.

Monocyte subset distribution in patients with stable atherosclerosis and elevated levels of lipoprotein(a).

Background: Lipoprotein(a) (Lp(a)) is a proatherogenic plasma lipoprotein currently established as an independent risk factor for the development of atherosclerotic disease and as a predictor for acute thrombotic complications. In addition, Lp(a) is the major carrier of proinflammatory oxidized phospholipids (OxPL). Today, atherosclerosis is considered to be an inflammatory disease of the vessel wall in which monocytes and monocyte-derived macrophages are crucially involved.

Avemar, a nontoxic fermented wheat germ extract, attenuates the growth of sensitive and 5-FdUrd/Ara-C cross-resistant H9 human lymphoma cells through induction of apoptosis.

Avemar (MSC) is a nontoxic fermented wheat germ extract, which has been shown to significantly improve the survival rate in patients suffering from various malignancies. We investigated its effects in sensitive and 5-FdUrd/Ara-C cross-resistant H9 human lymphoma cells. After 48 and 72 h of incubation, Avemar inhibited the growth of sensitive H9 cells with IC50 values of 290 and 200 microg/ml, whereas the growth of 5-FdUrd/Ara-C cross-resistant H9 cells was attenuated with IC50 values of 180 and 145 microg/ml, respectively.

Antitumor effects of KITC, a new resveratrol derivative, in AsPC-1 and BxPC-3 human pancreatic carcinoma cells.

Pancreatic cancer is a very aggressive malignant disease due to lack of early diagnosis and chemotherapeutic resistance of the tumor cells. There is distinct evidence that food derived polyphenols possess chemopreventive effects in the development of several cancers including pancreatic carcinoma. Resveratrol is one of those phenolic compounds found in grape skins and other fruits with known anticancer activity.

Biochemical effects of piceatannol in human HL-60 promyelocytic leukemia cells--synergism with Ara-C.

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene; PCA) is a naturally occurring metabolite of resveratrol (3,4',5-trihydroxy-trans-stilbene; RV). In this study, we identified additional biochemical targets of PCA in human HL-60 promyelocytic leukemia cells. Incubation with PCA led to a significant proportion of apoptotic cells and caused an arrest in the G2-M phase of the cell cycle.

N-hydroxy-N'-(3,4,5-trimethoxyphenyl)-3,4,5-trimethoxy-benzamidine, a novel resveratrol analog, inhibits ribonucleotide reductase in HL-60 human promyelocytic leukemia cells: synergistic antitumor activity with arabinofuranosylcytosine.

Resveratrol (3,4',5,-trihydroxystilbene, RV), an ingredient of wine, exhibits a broad spectrum of antiproliferative effects against human cancer cells. In order to develop a derivative with comparable effects, we modified the molecule by introducing additional methoxyl groups. The resulting novel RV analog, N-hydroxy-N'-(3,4,5-trimethoxyphenyl)-3,4,5-trimethoxybenzamidine (KITC), was investigated in HL-60 human promyelocytic leukemia cells.