No abstract

Cardiovascular disease (CVD) is the leading cause of mortality in the world, with most CVD-related deaths resulting from myocardial infarction or stroke. The main underlying cause of thrombosis and cardiovascular events is atherosclerosis, an inflammatory disease that can remain asymptomatic for long periods. There is an urgent need for therapeutic and diagnostic options in this area. Atherosclerotic plaques contain autoantibodies 1,2 , and there is a connection between atherosclerosis and autoimmunity 3 . However, the immunogenic trigger and the effects of the autoantibody response during atherosclerosis are not well understood [3][4][5] . Here we performed high-throughput single-cell analysis of the atherosclerosis-associated antibody repertoire. Antibody gene sequencing of more than 1,700 B cells from atherogenic Ldlr −/− and control mice identified 56 antibodies expressed by in-vivo-expanded clones of B lymphocytes in the context of atherosclerosis. One-third of the expanded antibodies were reactive against atherosclerotic plaques, indicating that various antigens in the lesion can trigger antibody responses. Deep proteomics analysis identified ALDH4A1, a mitochondrial dehydrogenase involved in proline metabolism, as a target antigen of one of these autoantibodies, A12. ALDH4A1 distribution is altered during atherosclerosis, and circulating ALDH4A1 is increased in mice and humans with atherosclerosis, supporting the potential use of ALDH4A1 as a disease biomarker. Infusion of A12 antibodies into Ldlr −/− mice delayed plaque formation and reduced circulating free cholesterol and LDL, suggesting that anti-ALDH4A1 antibodies can protect against atherosclerosis progression and might have therapeutic potential in CVD.Atherosclerosis is a chronic inflammatory disease that leads to the formation of atheroma plaques in the arteries and is the main underlying cause of thrombosis, ischaemic heart disease and stroke 6 . The inflammatory reaction during atherosclerosis is believed to be triggered by the retention and subsequent oxidation (ox) of low-density lipoprotein (LDL) in the vessel sub-endothelium space 7 . In addition, the adaptive arm of the immune response is known to be critical during atherosclerosis [8][9][10] . Antibodies were first detected in atheroma plaques decades ago, and both protective and pathogenic functions have been attributed to B cells and the antibody immune response during atherosclerosis development 3,[11][12][13][14][15][16] . However, knowledge about the underlying antigenic triggers of this response and their effects on atherosclerosis 3 remains limited, as most studies have focused on oxidation-specific neoepitopes (OSEs) such as those contained in oxLDL [17][18][19][20][21][22] . Here, we performed an unbiased, high-throughput single-cell study of the antibody repertoire associated with atherosclerosis and identified an antibody-antigen pair with strong diagnostic and therapeutic potential.To study the antibody immune response associated with atherosclerosis, we made use of Ldlr −/− mi...

In the version of the article originally published, in the top immunoblot (loading control) in Figure 5f, the right half was incorrectly a mirror-image duplication of the left half. The correct immunoblot from a replicate experiment is now presented (along with the corresponding bottom immunoblot). In the version of this article initially published online, the identification of dermal and epidermal γδ T cells in the legend for Figure 3f was reversed; a label was missing above the far left column of Figure 4c; and the red and blue lines were switched in the keys for the far right plots in Figure 6i. The legend for Figure 3f should read "...identified by high expression (top right; epidermal) or low expression (bottom right; dermal) of the γδ TCR. " The far left column in Figure 4c should include the label "CD69-KO" above. The correct keys for Figure 6i are as follows: blue line, FIZC (37 °C), and red line, FICZ + BCH (37 °C); and blue line, CD69-KO (37 °C), and red line, WT (37 °C).

The composition and physical properties of the extracellular matrix (ECM) critically influence tumor progression, but the molecular mechanisms underlying ECM layering are poorly understood. Tumor–stroma interaction critically depends on cell communication mediated by exosomes, small vesicles generated within multivesicular bodies (MVBs). We show that caveolin-1 (Cav1) centrally regulates exosome biogenesis and exosomal protein cargo sorting through the control of cholesterol content at the endosomal compartment/MVBs. Quantitative proteomics profiling revealed that Cav1 is required for exosomal sorting of ECM protein cargo subsets, including Tenascin-C (TnC), and for fibroblast-derived exosomes to efficiently deposit ECM and promote tumor invasion. Cav1-driven exosomal ECM deposition not only promotes local stromal remodeling but also the generation of distant ECM-enriched stromal niches in vivo. Cav1 acts as a cholesterol rheostat in MVBs, determining sorting of ECM components into specific exosome pools and thus ECM deposition. This supports a model by which Cav1 is a central regulatory hub for tumor–stroma interactions through a novel exosome-dependent ECM deposition mechanism.

BackgroundCardiac steatosis and apoptosis are key processes in diabetic cardiomyopathy, but the underlying mechanisms have not been elucidated, leading to a lack of effective therapy. The mineralocorticoid receptor blocker, eplerenone, has demonstrated anti-fibrotic actions in the diabetic heart. However, its effects on the fatty-acid accumulation and apoptotic responses have not been revealed.MethodsNon-hypertensive Zucker Diabetic Fatty (ZDF) rats received eplerenone (25 mg/kg) or vehicle. Zucker Lean (ZL) rats were used as control (n = 10, each group). After 16 weeks, cardiac structure and function was examined, and plasma and hearts were isolated for biochemical and histological approaches. Cultured cardiomyocytes were used for in vitro assays to determine the direct effects of eplerenone on high fatty acid and high glucose exposed cells.ResultsIn contrast to ZL, ZDF rats exhibited hyperglycemia, hyperlipidemia, insulin-resistance, cardiac steatosis and diastolic dysfunction. The ZDF myocardium also showed increased mitochondrial oxidation and apoptosis. Importantly, eplerenone mitigated these events without altering hyperglycemia. In cultured cardiomyocytes, high-concentrations of palmitate stimulated the fatty-acid uptake (in detriment of glucose assimilation), accumulation of lipid metabolites, mitochondrial dysfunction, and apoptosis. Interestingly, fatty-acid uptake, ceramides formation and apoptosis were also significantly ameliorated by eplerenone.ConclusionsBy blocking mineralocorticoid receptors, eplerenone may attenuate cardiac steatosis and apoptosis, and subsequent remodelling and diastolic dysfunction in obese/type-II diabetic rats.