Vaccination to modulate atherosclerosis

Atheroprotective Aspects of Heat Shock Proteins

Atherosclerosis is a major global health problem. Being a harbinger of a large number of cardiovascular diseases, it ultimately leads to morbidity and mortality. At the same time, effective measures for the prevention and treatment of atherosclerosis have not been developed, to date. All available therapeutic options have a number of limitations. To understand the mechanisms behind the triggering and development of atherosclerosis, a deeper understanding of molecular interactions is needed. Heat shock proteins are important for the normal functioning of cells, actively helping cells adapt to gradual changes in the environment and survive in deadly conditions. Moreover, multiple HSP families play various roles in the progression of cardiovascular disorders. Some heat shock proteins have been shown to have antiatherosclerotic effects, while the role of others remains unclear. In this review, we considered certain aspects of the antiatherosclerotic activity of a number of heat shock proteins.

Acute Coronary Syndrome: Disparities of Pathophysiology and Mortality with and without Peripheral Artery Disease

There are a number of devastating complications associated with peripheral artery disease, including limb amputations and acute limb ischemia. Despite the overlap, atherosclerotic diseases have distinct causes that need to be differentiated and managed appropriately. In coronary atherosclerosis, thrombosis is often precipitated by rupture or erosion of fibrous caps around atheromatous plaques, which leads to acute coronary syndrome. Regardless of the extent of atherosclerosis, peripheral artery disease manifests itself as thrombosis. Two-thirds of patients with acute limb ischemia have thrombi associated with insignificant atherosclerosis. A local thrombogenic or remotely embolic basis of critical limb ischemia may be explained by obliterative thrombi in peripheral arteries of patients without coronary artery-like lesions. Studies showed that thrombosis of the above-knee arteries was more commonly due to calcified nodules, which are the least common cause of luminal thrombosis associated with acute coronary events in patients with acute coronary syndrome. Cardiovascular mortality was higher in peripheral artery disease without myocardial infarction/stroke than in myocardial infarction/stroke without peripheral artery disease. The aim of this paper is to gather published data regarding the disparities of acute coronary syndrome with and without peripheral artery disease in terms of pathophysiology and mortality.

Lipoprotein(a) and Its Autoantibodies in Association with Calcific Aortic Valve Stenosis

Aortic valve stenosis is the most common valvular heart disease in the Western world. Lipoprotein(a) (Lp(a)) is an independent risk factor of coronary heart disease (CHD) and calcific aortic valve stenosis (CAVS). The aim of this study was to assess the role of Lp(a) and its autoantibodies [autoAbs] in CAVS in patients with and without CHD. We included 250 patients (mean age 69 ± 3 years, males 42%) and divided them into three groups. There were two groups of patients with CAVS depending on the presence (group 1) or absence of CHD (group 2). The control group included the patients without CHD or CAVS. According to logistic regression analysis, levels of Lp(a), IgM autoAbs to oxidized Lp(a) (oxLp(a)), and age were independent predictors of CAVS. A concomitant increase in Lp(a) level (≥30 mg/dL) and a decrease in IgM autoAbs concentration (<9.9 lab. Units) are associated with CAVS with an odds ratio (OR) of 6.4, p < 0.01, and with CAVS and CHD with an OR of 17.3, p < 0.001. IgM autoantibodies to oxLp(a) are associated with calcific aortic valve stenosis regardless of Lp(a) concentration and other risk factors. Higher Lp(a) and lower IgM autoantibodies to oxLp(a) levels are associated with a much higher risk of calcific aortic valve stenosis.

Crosstalk between dendritic cells and T lymphocytes during atherogenesis: Focus on antigen presentation and break of tolerance

Atherosclerosis is a chronic disease resulting from an impaired lipid and immune homeostasis, where the interaction between innate and adaptive immune cells leads to the promotion of atherosclerosis-associated immune-inflammatory response. Emerging evidence has suggested that this response presents similarities to the reactivity of effector immune cells toward self-epitopes, often as a consequence of a break of tolerance. In this context, dendritic cells, a heterogeneous population of antigen presenting cells, play a key role in instructing effector T cells to react against foreign antigens and T regulatory cells to maintain tolerance against self-antigens and/or to patrol for self-reactive effector T cells. Alterations in this delicate balance appears to contribute to atherogenesis. The aim of this review is to discuss different DC subsets, and their role in atherosclerosis as well as in T cell polarization. Moreover, we will discuss how loss of T cell tolerogenic phenotype participates to the immune-inflammatory response associated to atherosclerosis and how a better understanding of these mechanisms might result in designing immunomodulatory therapies targeting DC-T cell crosstalk for the treatment of atherosclerosis-related inflammation.

Association of immunoglobulin G N-glycosylation with carotid atherosclerotic plaque phenotypes and actual clinical cardiovascular events: a study protocol for a longitudinal prospective cohort study

INTRODUCTION

Immune-inflammatory response plays a key role in the pathogenesis of atherosclerosis. IgG N-glycosylation is reported to be associated with the 10-year atherosclerotic cardiovascular disease risk score and subclinical atherosclerosis. However, the relationship of IgG glycosylation with actual clinical cardiovascular disease (CVD) events and plaque phenotypes has rarely been investigated. Therefore, this study aims to understand whether IgG glycosylation traits are correlated with actual clinical CVD events and plaque phenotypes.

METHODS AND ANALYSIS

Designed to verify the efficacy of IgG glycosylation as a risk for CVD events and screen potential biomarkers of CVD to prevent atherosclerosis occurrence, this longitudinal prospective cohort study will be conducted at the First Affiliated Hospital of Shantou University Medical College, China. In total, 2720 participants routinely examined by carotid ultrasound will be divided into different groups according to plaque phenotype characteristics. Ultra-performance liquid chromatography will be performed to separate and detect IgG N-glycans in serum collected at baseline and at the end of the first, second and third years. The primary outcome is the actual clinical CVD composite events, including non-fatal myocardial infarction, death due to coronary heart disease, and fatal or non-fatal stroke.

ETHICS AND DISSEMINATION

The Clinical Ethics Committee of the First Affiliated Hospital of Shantou University Medical College approved this study (number: B-2021-127). Findings of this study will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100048740.

Circulating Autoantibodies Recognizing Immunodominant Epitopes From Human Apolipoprotein B Associate With Cardiometabolic Risk Factors, but Not With Atherosclerotic Disease

Rationale

Atherosclerosis is a chronic inflammatory disease of large arteries that involves an autoimmune response with autoreactive T cells and auto-antibodies recognizing Apolipoprotein B (ApoB), the core protein of low-density lipoprotein (LDL). Here, we aimed to establish a clinical association between circulating human ApoB auto-antibodies with atherosclerosis and its clinical risk factors using a novel assay to detect auto-antibodies against a pool of highly immunogenic ApoB-peptides.

Methods and Results

To detect polyclonal IgM- and IgG-antibodies recognizing ApoB, we developed a chemiluminescent sandwich ELISA with 30 ApoB peptides selected by an in silico assay for a high binding affinity to MHC-II, which cover more than 80% of known MHC-II variants in a Caucasian population. This pre-selection of immunogenic self-peptides accounted for the high variability of human MHC-II, which is fundamental to allow T cell dependent generation of IgG antibodies. We quantified levels of ApoB-autoantibodies in a clinical cohort of 307 patients that underwent coronary angiography. Plasma anti-ApoB IgG and IgM concentrations showed no differences across healthy individuals (n = 67), patients with coronary artery disease (n = 179), and patients with an acute coronary syndrome (n = 61). However, plasma levels of anti-ApoB IgG, which are considered pro-inflammatory, were significantly increased in patients with obesity (p = 0.044) and arterial hypertension (p < 0.0001). In addition, patients diagnosed with the metabolic syndrome showed significantly elevated Anti-ApoB IgG (p = 0.002). Even when normalized for total plasma IgG, anti-ApoB IgG remained highly upregulated in hypertensive patients (p < 0.0001). We observed no association with triglycerides, total cholesterol, VLDL, or LDL plasma levels. However, total and normalized anti-ApoB IgG levels negatively correlated with HDL. In contrast, total and normalized anti-ApoB IgM, that have been suggested as anti-inflammatory, were significantly lower in diabetic patients (p = 0.012) and in patients with the metabolic syndrome (p = 0.005).

Conclusion

Using a novel ELISA method to detect auto-antibodies against ApoB in humans, we show that anti-ApoB IgG associate with cardiovascular risk factors but not with the clinical appearance of atherosclerosis, suggesting that humoral immune responses against ApoB are shaped by cardiovascular risk factors but not disease status itself. This novel tool will be helpful to develop immune-based risk stratification for clinical atherosclerosis in the future.

Redox regulation of age-associated defects in generation and maintenance of T cell self-tolerance and immunity to foreign antigens

Thymic atrophy reduces naive T cell production and contributes to increased susceptibility to viral infection with age. Expression of tissue-restricted antigen (TRA) genes also declines with age and has been thought to increase autoimmune disease susceptibility. We find that diminished expression of a model TRA gene in aged thymic stromal cells correlates with impaired clonal deletion of cognate T cells recognizing an autoantigen involved in atherosclerosis. Clonal deletion in the polyclonal thymocyte population is also perturbed. Distinct age-associated defects in the generation of antigen-specific T cells include a conspicuous decline in generation of T cells recognizing an immunodominant influenza epitope. Increased catalase activity delays thymic atrophy, and here, we show that it mitigates declining production of influenza-specific T cells and their frequency in lung after infection, but does not reverse declines in TRA expression or efficient negative selection. These results reveal important considerations for strategies to restore thymic function.

Anti-inflammatory Strategies in Atherosclerosis

Atherosclerotic vascular disease and its related complications are the major cause of mortality in Western societies. Atherosclerosis is a chronic inflammatory disease of the arterial wall triggered by traditional and nontraditional risk factors and mediated by inflammatory and immune responses. Recent clinical trials provided compelling evidence corroborating that atherosclerosis is an inflammatory disease and demonstrated efficacy of anti-inflammatory interventions in reducing cardiovascular events and mortality. Traditional risk factors drive vascular inflammation, further justifying the instrumental role of intensified risk factor management in attenuating and preventing atherosclerotic disease and complications. Promising therapeutic approaches specifically related to inhibition of inflammation span traditional anti-inflammatory drugs, specific immunomodulation, and development of vaccination against atherosclerotic disease. Here, we review the inflammatory component in atherogenesis, the available evidence from clinical trials evaluating efficacy of therapeutic anti-inflammatory interventions in patients with high cardiovascular risk, and discuss potential future targets for anti-inflammatory or immune modulatory treatment in atherosclerotic cardiovascular disease.

Modulating Autoimmunity against LDL: Development of a Vaccine against Atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall that leads to the build-up of occluding atherosclerotic plaques. Its clinical sequelae, myocardial infarction and stroke, represent the most frequent causes of death worldwide. Atherosclerosis is a multifactorial pathology that involves traditional risk factors and chronic low-grade inflammation in the atherosclerotic plaque and systemically. This process is accompanied by a strong autoimmune response that involves autoreactive T cells in lymph nodes and atherosclerotic plaques, as well as autoantibodies that recognize low-density lipoprotein (LDL) and its main protein component apolipoprotein B (ApoB). In the past 60 years, numerous preclinical observations have suggested that immunomodulatory vaccination with LDL, ApoB, or its peptides has the potential to specifically dampen autoimmunity, enhance tolerance to atherosclerosis-specific antigens, and protect from experimental atherosclerosis in mouse models. Here, we summarize and discuss mechanisms, challenges, and therapeutic opportunities of immunomodulatory vaccination and other strategies to enhance protective immunity in atherosclerosis.

The potential targets in immunotherapy of atherosclerosis

Cardiovascular disease is the most common cause of death, which has the highest mortality rate worldwide. Although a diverse range of inflammatory diseases can affect the cardiovascular system, however, heart failure and stroke occur due to atherosclerosis. Atherosclerosis is a chronic autoinflammatory disease of small to large vessels in which different immune mediators are involved in lipid plaque formation and inflammatory vascular remodeling process. A better understanding of the pathophysiology of atherosclerosis may lead to uncovering immunomodulatory therapies. Despite present diagnostic and therapeutic methods, the lack of immunotherapy in the prevention and treatment of atherosclerosis is perceptible. In this review, we will discuss the promising immunological-based therapeutics and novel preventive approaches for atherosclerosis. This study could provide new insights into a better perception of targeted therapeutic pathways and biological therapies.

Identification of potential genes associated with immune cell infiltration in atherosclerosis

BACKGROUND

This study aimed to analyze the potential genes associated with immune cell infiltration in atherosclerosis (AS).

METHODS

Gene expression profile data (GSE57691) of human arterial tissue samples were downloaded, and differentially expressed RNAs (DERNAs; long-noncoding RNA [lncRNAs], microRNAs [miRNAs], and messenger RNAs [mRNAs]) in AS vs. control groups were selected. Based on genome-wide expression levels, the proportion of infiltrating immune cells in each sample was assessed. Genes associated with immune infiltration were selected, and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Finally, a competing endogenous RNA (ceRNA) network was constructed, and the genes in the network were subjected to functional analyses.

RESULTS

A total of 1749 DERNAs meeting the thresholds were screened, including 1673 DEmRNAs, 63 DElncRNAs, and 13 DEmiRNAs. The proportions of B cells, CD4+ T cells, and CD8+ T cells were significantly different between the two groups. In total, 341 immune-associated genes such as HBB, FCN1, IL1B, CXCL8, RPS27A, CCN3, CTSZ, and SERPINA3 were obtained that were enriched in 70 significantly related GO biological processes (such as immune response) and 15 KEGG pathways (such as chemokine signaling pathway). A ceRNA network, including 33 lncRNAs, 11 miRNAs, and 216 mRNAs, was established.

CONCLUSION

Genes such as FCN1, IL1B, and SERPINA3 may be involved in immune cell infiltration and may play important roles in AS progression via ceRNA regulation.

CD8+ T Cells in Atherosclerosis

Atherosclerotic lesions are populated by cells of the innate and adaptive immune system, including CD8⁺ T cells. The CD8⁺ T cell infiltrate has recently been characterized in mouse and human atherosclerosis and revealed activated, cytotoxic, and possibly dysfunctional and exhausted cell phenotypes. In mouse models of atherosclerosis, antibody-mediated depletion of CD8⁺ T cells ameliorates atherosclerosis. CD8⁺ T cells control monopoiesis and macrophage accumulation in early atherosclerosis. In addition, CD8⁺ T cells exert cytotoxic functions in atherosclerotic plaques and contribute to macrophage cell death and necrotic core formation. CD8⁺ T cell activation may be antigen-specific, and epitopes of atherosclerosis-relevant antigens may be targets of CD8⁺ T cells and their cytotoxic activity. CD8⁺ T cell functions are tightly controlled by costimulatory and coinhibitory immune checkpoints. Subsets of regulatory CD25⁺CD8⁺ T cells with immunosuppressive functions can inhibit atherosclerosis. Importantly, local cytotoxic CD8⁺ T cell responses may trigger endothelial damage and plaque erosion in acute coronary syndromes. Understanding the complex role of CD8⁺ T cells in atherosclerosis may pave the way for defining novel treatment approaches in atherosclerosis. In this review article, we discuss these aspects, highlighting the emerging and critical role of CD8⁺ T cells in atherosclerosis.

Pathogenic Autoimmunity in Atherosclerosis Evolves From Initially Protective Apolipoprotein B100-Reactive CD4+ T-Regulatory Cells

BACKGROUND

Throughout the inflammatory response that accompanies atherosclerosis, autoreactive CD4⁺ T-helper cells accumulate in the atherosclerotic plaque. Apolipoprotein B₁₀₀ (apoB), the core protein of low-density lipoprotein, is an autoantigen that drives the generation of pathogenic T-helper type 1 (T_H1) cells with proinflammatory cytokine secretion. Clinical data suggest the existence of apoB-specific CD4⁺ T cells with an atheroprotective, regulatory T cell (T_reg) phenotype in healthy individuals. Yet, the function of apoB-reactive T_regs and their relationship with pathogenic T_H1 cells remain unknown.

METHODS

To interrogate the function of autoreactive CD4⁺ T cells in atherosclerosis, we used a novel tetramer of major histocompatibility complex II to track T cells reactive to the mouse self-peptide apo B_978-993 (apoB⁺) at the single-cell level.

RESULTS

We found that apoB⁺ T cells build an oligoclonal population in lymph nodes of healthy mice that exhibit a T_reg-like transcriptome, although only 21% of all apoB⁺ T cells expressed the T_reg transcription factor FoxP3 (Forkhead Box P3) protein as detected by flow cytometry. In single-cell RNA sequencing, apoB⁺ T cells formed several clusters with mixed T_H signatures that suggested overlapping multilineage phenotypes with pro- and anti-inflammatory transcripts of T_H1, T helper cell type 2 (T_H2), and T helper cell type 17 (T_H17), and of follicular-helper T cells. ApoB⁺ T cells were increased in mice and humans with atherosclerosis and progressively converted into pathogenic T_H1/T_H17-like cells with proinflammatory properties and only a residual T_reg transcriptome. Plaque T cells that expanded during progression of atherosclerosis consistently showed a mixed T_H1/T_H17 phenotype in single-cell RNA sequencing. In addition, we observed a loss of FoxP3 in a fraction of apoB⁺ T_regs in lineage tracing of hyperlipidemic Apoe^-/- mice. In adoptive transfer experiments, converting apoB⁺ T_regs failed to protect from atherosclerosis.

CONCLUSIONS

Our results demonstrate an unexpected mixed phenotype of apoB-reactive autoimmune T cells in atherosclerosis and suggest an initially protective autoimmune response against apoB with a progressive derangement in clinical disease. These findings identify apoB autoreactive T_regs as a novel cellular target in atherosclerosis.

Lymphatic Capillaries in Aging

The lymphatic system is responsible for fluid drainage from almost every organ in the body. It sustains tissue homeostasis and is also a central part of the immune system. With the discovery of cell-specific markers and transgenic mouse models, it has become possible to gain some insight into the developmental and functional roles of lymphatic endothelial cells (LECs). Only recently, a more direct regulatory role has been assigned to LECs in their functions in immunity responses and chronic diseases. Here, we discuss the changes occurring in aged lymphatic system and the role of lymphatic capillaries in some age-related diseases and experimental animal models.

A new strategy for the treatment of atherothrombosis - inhibition of inflammation

Improvement in the prognosis of patients at risk of atherothrombotic events is based on three pillars - slowing down the process of atherogenesis (i.e. the development of atherosclerotic plaque), stabilizing the current atherosclerotic plaque, and reducing the risk of thrombotic occlusion in cases with unstable atherosclerotic plaque. The current prophylaxis has so far taken into consideration the adjustment of several risk factors, including dyslipidemia, arterial hypertension, smoking, and diabetes through lifestyle changes or pharmacological therapies. An essential part of prophylaxis is the anti-thrombotic strategy, especially anti-platelet therapy. Recently, a new pathway has been developed, based on reducing the activity of the inflammatory process with NLRP3 inflammasome, specifically a monoclonal antibody against interleukin 1beta (canakinumab). The efficacy and safety of this treatment, in secondary prevention, were documented in the CANTOS study. Other therapeutic procedures, including suppression of the inflammatory component of atherogenesis, are at the stage of clinical assessment.

Thymic stromal lymphopoietin is a key cytokine for the immunomodulation of atherogenesis with Freund's adjuvant

Adaptive immune responses regulate the development of atherosclerosis, with a detrimental effect of type 1 but a protective role of type 2 immune responses. Immunization of Apolipoprotein E‐deficient (ApoE^−/−) mice with Freund's adjuvant inhibits the development of atherosclerosis. However, the underlying mechanisms are not fully understood. Thymic stromal lymphopoietin (TSLP) is an IL7‐like cytokine with essential impact on type 2 immune responses (Th2). Thymic stromal lymphopoietin is strongly expressed in epithelial cells of the skin, but also in various immune cells following appropriate stimulation. In this study, we investigated whether TSLP may be crucial for the anti‐atherogenic effect of Freund's adjuvant. Subcutaneous injection of complete Freund's adjuvant (CFA) rapidly led to the expression of TSLP and IL1β at the site of injection. In male mice, CFA‐induced TSLP occurred in immigrated monocytes—and not epithelial cells—and was dependent on NLRP3 inflammasome activation and IL1β‐signalling. In females, CFA‐induced TSLP was independent of IL1β and upon ovariectomy. CFA/OVA led to a more pronounced imbalance of the T cell response in TSLPR^−/− mice, with increased INFγ/IL4 ratio compared with wild‐type controls. To test whether TSLP contributes to the anti‐atherogenic effects of Freund's adjuvant, we treated ApoE^−/− and ApoE^−/−/TSLPR^−/− mice with either CFA/IFA or PBS. ApoE^−/− mice showed less atherogenesis upon CFA/IFA compared with PBS injections. ApoE^−/−/TSLPR^−/− mice had no attenuation of atherogenesis upon CFA/IFA treatment. Freund's adjuvant executes significant immune‐modulating effects via TSLP induction. TSLP‐TSLPR signalling is critical for CFA/IFA‐mediated attenuation of atherosclerosis.

Germinal Center-Derived Antibodies Promote Atherosclerosis Plaque Size and Stability

BACKGROUND

Atherosclerosis progression is modulated by interactions with the adaptive immune system. Humoral immunity can help protect against atherosclerosis formation; however, the existence, origin, and function of putative atherogenic antibodies are controversial. How such atherosclerosis-promoting antibodies could affect the specific composition and stability of plaques, as well as the vasculature generally, remains unknown.

METHODS

We addressed the overall contribution of antibodies to atherosclerosis plaque formation, composition, and stability in vivo (1) with mice that displayed a general loss of antibodies, (2) with mice that had selectively ablated germinal center-derived IgG production, or (3) through interruption of T-B-cell interactions and further studied the effects of antibody deficiency on the aorta by transcriptomics.

RESULTS

Here, we demonstrate that atherosclerosis-prone mice with attenuated plasma cell function manifest reduced plaque burden, indicating that antibodies promote atherosclerotic lesion size. However, the composition of the plaque was altered in antibody-deficient mice, with an increase in lipid content and decreases in smooth muscle cells and macrophages, resulting in an experimentally validated vulnerable plaque phenotype. Furthermore, IgG antibodies enhanced smooth muscle cell proliferation in vitro in an Fc receptor-dependent manner, and antibody-deficient mice had decreased neointimal hyperplasia formation in vivo. These IgG antibodies were shown to be derived from germinal centers, and mice genetically deficient for germinal center formation had strongly reduced atherosclerosis plaque formation. mRNA sequencing of aortas revealed that antibodies are required for the sufficient expression of multiple signal-induced and growth-promoting transcription factors and that aortas undergo large-scale metabolic reprograming in their absence. Using an elastase model, we demonstrated that absence of IgG results in an increased severity of aneurysm formation.

CONCLUSIONS

We propose that germinal center-derived IgG antibodies promote the size and stability of atherosclerosis plaques, through promoting arterial smooth muscle cell proliferation and maintaining the molecular identity of the aorta. These results could have implications for therapies that target B cells or B-T-cell interactions because the loss of humoral immunity leads to a smaller but less stable plaque phenotype.

[Development of therapeutic vaccine for life style-related diseases]

In the 18^th century, Edward Jenner proposed the vaccine for smallpox as a first vaccine therapy based on the legend that a vaccinia prevents the infection with smallpox. Recently, the therapeutic target of vaccine will expand from infectious diseases to various diseases, such as amyloid β or tau vaccine for Alzheimer's disease. We are now going to develop a therapeutic vaccine to lifestyle-related diseases (i.e. high blood pressure), and aim to realize a novel therapy which will be injected once or twice per year from a daily medication. For this purpose, the appropriate choice of an antigen, carrier and adjuvants should be required to activate hormonal immunity by the vaccine, leading to efficient antibody production without toxicity, because the therapeutic target of our vaccine is an endogenous protein (i.e. hormone). The clinical advantage of this therapeutic vaccine is to improve the medical adherence and drug management because the multiple drug users are increased in particular old patients, so called polypharmacy. If the vaccine will take place of a part of medicine in future, it may give us a novel therapeutic option with several social benefits.

Immunity and Inflammation in Atherosclerosis

There is now overwhelming experimental and clinical evidence that atherosclerosis is a chronic inflammatory disease. Lessons from genome-wide association studies, advanced in vivo imaging techniques, transgenic lineage tracing mice, and clinical interventional studies have shown that both innate and adaptive immune mechanisms can accelerate or curb atherosclerosis. Here, we summarize and discuss the pathogenesis of atherosclerosis with a focus on adaptive immunity. We discuss some limitations of animal models and the need for models that are tailored to better translate to human atherosclerosis and ultimately progress in prevention and treatment.

Macrophages in Atherosclerosis Regression

Macrophages play a central role in the development of atherosclerotic cardiovascular disease (ASCVD), which encompasses coronary artery disease, peripheral artery disease, cerebrovascular disease, and aortic atherosclerosis. In each vascular bed, macrophages contribute to the maintenance of the local inflammatory response, propagate plaque development, and promote thrombosis. These central roles, coupled with their plasticity, makes macrophages attractive therapeutic targets in stemming the development of and stabilizing existing atherosclerosis. In the context of ASCVD, classically activated M1 macrophages initiate and sustain inflammation, and alternatively activated M2 macrophages resolve inflammation. However, this classification is now considered an oversimplification, and a greater understanding of plaque macrophage physiology in ASCVD is required to aid in the development of therapeutics to promote ASCVD regression. Reviewed herein are the macrophage phenotypes and molecular regulators characteristic of ASCVD regression, and the current murine models of ASCVD regression.

Serum Anti-Apo B Antibody Level as Residual CVD Marker in DM Patients under Statin Treatment

AIM

In the pathogenesis of atherosclerosis, autoantibodies have two-facedness of progression and protection. Previous reports have indicated that low autoantibody levels against apolipoprotein B-100 (apo B-100) could increase the risk of atherosclerotic cardiovascular diseases (CVD) in healthy subjects. In this study, we investigated the relationship between circulating anti-apo B-100 autoantibodies and the clinical parameters in Japanese diabetic patients with or without CVD.

METHODS

We measured the serum levels of anti-apo B-100 autoantibodies against native and malondialdehyde (MDA)-modified p45 or p210 epitopes, as well as anti-apo E autoantibodies, using enzyme-linked immunosorbent assay.

RESULTS

In patients with CVD, the circulating levels of IgG against native p45, MDA-modified p45, and MDA-modified p210 (IgG_N-45, IgG_MDA-45, and IgG_MDA-210) were significantly lower than those in patients without CVD, whereas no difference was observed in anti-apo E autoantibody levels. In addition, IgM_N-45, IgM_MDA-45, and IgG_MDA-45 were negatively correlated with LDL-C levels, whereas IgG_N-45 and IgG_N-210 were positively correlated with HbA1c levels. No correlation was observed between autoantibody levels and diabetic microangiopathy. In the statin-treated subgroup, IgG_MDA-45 and IgG_MDA-210 were significantly lower in patients with CVD than in those without CVD.

CONCLUSION

Measurement of serum anti-apo B-100 autoantibodies can be useful for the evaluation of CVD risk in patients with diabetes receiving statin treatment.

The Significance of Oxidized Low-Density Lipoprotein in Body Fluids as a Marker Related to Diseased Conditions

Oxidatively modified low-density lipoprotein (oxLDL) is known to be involved in various diseases, including cardiovascular diseases. The presence of oxLDL in the human circulatory system and in atherosclerotic lesions has been demonstrated using monoclonal antibodies. Studies have shown the significance of circulating oxLDL in various systemic diseases, including acute myocardial infarction and diabetic mellitus. Several different enzyme-linked immunosorbent assay (ELISA) procedures to measure oxLDL were utilized. Evidence has been accumulating that reveals changes in oxLDL levels under certain pathological conditions. Since oxLDL concentration tends to correlate with low-density lipoprotein (LDL)-cholesterol, the ratio of ox-LDL and LDL rather than oxLDL concentration alone has also been focused. In addition to circulating plasma, LDL and oxLDL are found in gingival crevicular fluid (GCF), where the ratio of oxLDL to LDL in GCF is much higher than in plasma. LDL and oxLDL levels in GCF show an increase in diabetic patients and periodontal patients, suggesting that GCF might be useful in examining systemic conditions. GCF oxLDL increased when the teeth were affected by periodontitis. It is likely that oxLDL levels in plasma and GCF could reflect oxidative stress and transfer efficacy in the circulatory system.

Cytokine Circuits in Cardiovascular Disease

Arterial inflammation is a hallmark of atherosclerosis, and appropriate management of this inflammation represents a major unmet therapeutic need for cardiovascular disease patients. Here, we review the diverse contributions of immune cells to atherosclerosis, the mechanisms of immune cell activation in this context, and the cytokine circuits that underlie disease progression. We discuss the recent application of these insights in the form of immunotherapy to treat cardiovascular disease and highlight how studies on the cardiovascular co-morbidity that arises in autoimmunity might reveal additional roles for cytokines in atherosclerosis. Currently, data point to interleukin-1β (IL-1β), tumor necrosis factor (TNF), and IL-17 as cytokines that, at least in some settings, are effective targets to reduce cardiovascular disease progression.

[Immunity and inflammation in atherosclerosis]

There is now overwhelming experimental and clinical evidence that arteriosclerosis is a chronic inflammatory disease. Lessons learned from genome-wide association studies, advanced in vivo imaging techniques, transgenic lineage tracing mice models and clinical interventional studies have shown that both innate and adaptive immune mechanisms can accelerate or curb arteriosclerosis. This article summarizes and discusses the pathogenesis of arteriosclerosis with a focus on the role of the adaptive immune system. Some limitations of animal models are discussed and the need for models that are tailored to better translate to human atherosclerosis and ultimately progress in prevention and treatment are emphasized.

Anticytokine Agents: Targeting Interleukin Signaling Pathways for the Treatment of Atherothrombosis

The recognition that atherosclerosis is a complex chronic inflammatory disorder mediated through both adaptive and innate immunity has led to the hypothesis that anticytokine therapies targeting specific IL (interleukin) signaling pathways could serve as powerful adjuncts to lipid lowering in the prevention and treatment of cardiovascular disease. Cytokines involved in human atherosclerosis can be broadly classified as proinflammatory and proatherogenic (such as IL-1, IL-6, and TNF [tumor necrosis factor]) or as anti-inflammatory and antiatherogenic (such as IL-10 and IL-1rA). The recent CANTOS (Canakinumab Anti-Inflammatory Thrombosis Outcomes Study) has shown that specific targeting of IL-1β can significantly reduce cardiovascular event rates without lipid or blood pressure lowering. In CANTOS, the magnitude of benefit of this cytokine-targeted approach to atherosclerosis treatment was associated to the magnitude of reduction of the central signaling cytokine IL-6 and the downstream clinical biomarker high-sensitivity CRP (C-reactive protein). By contrast, in the recent CIRT (Cardiovascular Inflammation Reduction Trial), low-dose methotrexate neither reduced IL-1β, IL-6, or high-sensitivity CRP nor lowered cardiovascular event rates. Taken together, these 2 contemporary trials provide proof of principle that focused cytokine inhibition, not broad-spectrum anti-inflammatory therapy, is likely to be crucial for atheroprotection. This review provides an overview of cytokines in atherosclerosis, the potential benefits and risks associated with targeted anticytokine therapies, and a look to the future of clinical practices addressing residual inflammatory risk.

The many faces of CD8+ T cells in atherosclerosis

PURPOSE OF REVIEW

Atherosclerosis and the clinical consequence of cardiovascular disease remain the leading cause of death worldwide. Both an increase in cholesterol levels, as well as immune responses drive the pathogenesis of this disease. Although much is known about the role of many immune cell subsets in atherogenesis, research into the role of CD8 T cells is limited.

RECENT FINDINGS

Both atheroprotective and atherogenic functions of CD8 T cells have been reported. On the one hand, the inflammatory cytokines produced by CD8 T cells exacerbate inflammatory responses, and the cytotoxic activity of these cells toward lesion-stabilizing cells such as endothelial cells drives the progression and instability of atherosclerotic lesions. On the other hand, cytotoxic activity toward antigen presenting cells and the presence of regulatory CD8 T-cell subsets dampen immunity and can limit atherosclerosis.

SUMMARY

Here we review the different roles of CD8 T cells in atherosclerosis and discuss possible treatment strategies targeting these cells to reduce atherosclerotic lesion burden.

Recent Advances in the Development of Vaccines for Diabetes, Hypertension, and Atherosclerosis

Vaccines are commonly used in the prevention of infectious diseases. The basic principle of vaccination is to use specific antigens, endogenous or exogenous to stimulate immunity against the specific antigens or cells producing them. Autoantigen or oligo vaccination has been used for disease animal models. More recently humanized monoclonal antibodies have been successfully used for the treatment of neoplastic disorders or familial hypercholesterolemia. Humanized monoclonal antibody therapy needs repeated injection, and the therapy is expensive. Therapeutic vaccination can lead to persistent immunized or immune tolerant against the therapeutic molecule(s) or site. However, immunization against those endogenous substances may also elicit persistent autoimmune reaction or destruction that do harm to health. Therefore, rigorous studies are needed before any clinical application. In this review, we briefly reviewed vaccines used in protection against common metabolic diseases including atherosclerosis, hypertension, and diabetes mellitus.

A clinically applicable adjuvant for an atherosclerosis vaccine in mice

Vaccination with MHC-II-restricted peptides from Apolipoprotein B (ApoB) with complete and incomplete Freund's adjuvant (CFA/IFA) is known to protect mice from atherosclerosis. This vaccination induces antigen-specific IgG1 and IgG2c antibody responses and a robust CD4 T cell response in lymph nodes. However, CFA/IFA cannot be used in humans. To find a clinically applicable adjuvant, we tested the effect of vaccinating Apoe-deficient mice with ApoB peptide P6 (TGAYSNASSTESASY). In a broad screening experiment, Addavax, a squalene-based oil-in-water adjuvant similar to MF59, was the only adjuvant that showed similar efficacy as CFA/IFA. This was confirmed in a confirmation experiment for both the aortic arch and whole aorta analyzed by en face analysis after atherosclerotic lesion staining. Mechanistically, restimulated peritoneal cells from mice immunized with P6 in Addavax released significant amounts of IL-10. Unlike P6 in CFA/IFA, vaccination with P6 in Addavax did not induce any detectable IgG1 or IgG2c antibodies to P6. These data suggest that squalene-based adjuvants such as MF59 are good candidate adjuvants for developing a clinically effective atherosclerosis vaccine.

Heat shock proteins and cardiovascular disease

The development of stress drives a host of biological responses that include the overproduction of a family of proteins named heat shock proteins (HSPs), because they were initially studied after heat exposure. HSPs are evolutionarily preserved proteins with a high degree of interspecies homology. HSPs are intracellular proteins that also have extracellular expression. The primary role of HSPs is to protect cell function by preventing irreversible protein damage and facilitating molecular traffic through intracellular pathways. However, in addition to their chaperone role, HSPs are immunodominant molecules that stimulate natural as well as disease-related immune reactivity. The latter may be a consequence of molecular mimicry, generating cross-reactivity between human HSPs and the HSPs of infectious agents. Autoimmune reactivity driven by HSPs could also be the result of enhancement of the immune response to peptides generated during cellular injury and of their role in the delivery of peptides to the major histocompatibility complex in antigen-presenting cells. In humans, HSPs have been found to participate in the pathogenesis of a large number of diseases. This review is focused on the role of HSPs in atherosclerosis and essential hypertension.

Assessment of Carrot Callus as Biofactories of an Atherosclerosis Oral Vaccine Prototype

Atherosclerosis is a pathology leading to cardiovascular diseases with high epidemiologic impact; thus, new therapies are required to fight this global health issue. Immunotherapy is a feasible approach to treat atherosclerosis and given that genetically engineered plants are attractive hosts for vaccine development; we previously proved that the plant cell is able to synthesize a chimeric protein called CTB:p210:CETPe, which is composed of the cholera toxin B subunit (CTB) as immunogenic carrier and target epitopes from the cholesteryl ester transfer protein (CETP_461-476) and apolipoprotein B100 (p210). Since CTB:p210:CETPe was expressed in tobacco at sufficient levels to evoke humoral responses in mice, its expression in carrot was explored in the present study looking to develop a vaccine in a safe host amenable for oral delivery; avoiding the purification requirement. Carrot cell lines expressing CTB:p210:CETPe were developed, showing accumulation levels up to 6.1 µg/g dry weight. An immunoblot analysis revealed that the carrot-made protein is antigenic and an oral mice immunization scheme led to evidence on the immunogenic activity of this protein; revealing its capability of inducing serum IgG responses against p210 and CETP epitopes. This study represents a step forward in the development of an attractive oral low-cost vaccine to treat atherosclerosis.

Atherosclerosis and autoimmunity: a growing relationship

Atherosclerosis is regarded as one of the leading causes of mortality and morbidity in the world. Nowadays, it seems that atherosclerosis cannot be defined merely through the Framingham traditional risk factors and that autoimmunity settings exert a remarkable role in its mechanobiology. Individuals with autoimmune disorders show enhanced occurrence of cardiovascular complications and subclinical atherosclerosis. The mechanisms underlying the atherosclerosis in disorders like rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid syndrome, systemic sclerosis and Sjögren's syndrome, seem to be the classical risk factors. However, chronic inflammatory processes and abnormal immune function may also be involved in atherosclerosis development. Autoantigens, autoantibodies, infectious agents and pro-inflammatory mediators exert a role in that process. Being armed with the mechanisms underlying autoimmunity in the etiopathogenesis of atherosclerosis in rheumatic autoimmune disorders and the shared etiologic pathway may result in substantial developing therapeutics for these patients.

Oxidative Stress Induces HSP90 Upregulation on the Surface of Primary Human Endothelial Cells: Role of the Antioxidant 7,8-Dihydroxy-4-methylcoumarin in Preventing HSP90 Exposure to the Immune System

We have previously demonstrated that human heat shock protein 90 (HSP90), an intracellular self protein, is the target of cellular and humoral autoimmune responses in patients with carotid atherosclerosis. In this study, we evaluated in vitro whether oxidative stress, a feature of atherosclerotic plaque, alters HSP90 expression in endothelial cells, thus inducing surface localization of this molecule and whether the antioxidant compound 7,8-dihydroxy-4-methylcoumarin (7,8-DHMC) is able to prevent oxidative stress-induced alterations of HSP90 localization. By the use of flow cytometry, immunofluorescence, enzyme-linked immunosorbent assay, and semiquantitative reverse-transcription polymerase chain reaction, we demonstrated that exposure of human umbilical vein endothelial cells (HUVEC) to the prooxidant compound H₂O₂ upregulated HSP90 surface expression and reduced its secretion without altering HSP90 gene expression and intracytoplasmic protein levels. Pretreatment of HUVEC with 7,8-DHMC prevented H₂O₂-induced alterations of HSP90 cellular distribution and secretion. Our results suggest that the strong oxidative conditions of atherosclerotic plaques promote the upregulation of HSP90 surface expression on endothelial cells, thus rendering the protein a possible target of autoimmune reactions. The antioxidant 7,8-DHMC, by preventing oxidative-stress-triggered HSP90 surface upregulation, may be useful to counteract possible autoreactive reactions to HSP90.

Alternative RNA splicing in the endothelium mediated in part by Rbfox2 regulates the arterial response to low flow

Low and disturbed blood flow drives the progression of arterial diseases including atherosclerosis and aneurysms. The endothelial response to flow and its interactions with recruited platelets and leukocytes determine disease progression. Here, we report widespread changes in alternative splicing of pre-mRNA in the flow-activated murine arterial endothelium in vivo. Alternative splicing was suppressed by depletion of platelets and macrophages recruited to the arterial endothelium under low and disturbed flow. Binding motifs for the Rbfox-family are enriched adjacent to many of the regulated exons. Endothelial deletion of Rbfox2, the only family member expressed in arterial endothelium, suppresses a subset of the changes in transcription and RNA splicing induced by low flow. Our data reveal an alternative splicing program activated by Rbfox2 in the endothelium on recruitment of platelets and macrophages and demonstrate its relevance in transcriptional responses during flow-driven vascular inflammation.

Heat Shock Proteins in Vascular Diabetic Complications: Review and Future Perspective

Heat shock proteins (HSPs) are a large family of proteins highly conserved throughout evolution because of their unique cytoprotective properties. Besides assisting protein refolding and regulating proteostasis under stressful conditions, HSPs also play an important role in protecting cells from oxidative stress, inflammation, and apoptosis. Therefore, HSPs are crucial in counteracting the deleterious effects of hyperglycemia in target organs of diabetes vascular complications. Changes in HSP expression have been demonstrated in diabetic complications and functionally related to hyperglycemia-induced cell injury. Moreover, associations between diabetic complications and altered circulating levels of both HSPs and anti-HSPs have been shown in clinical studies. HSPs thus represent an exciting therapeutic opportunity and might also be valuable as clinical biomarkers. However, this field of research is still in its infancy and further studies in both experimental diabetes and humans are required to gain a full understanding of HSP relevance. In this review, we summarize current knowledge and discuss future perspective.

Elevated sodium leads to the increased expression of HSP60 and induces apoptosis in HUVECs

Atherosclerosis is the leading cause of death in the world. We have previously shown that expression of heat shock protein 60 (HSP60) on the surface of endothelial cells is the main cause of initiating the disease as it acts as a T cell auto-antigen and can be triggered by classical atherosclerosis risk factors, such as infection (e.g. Chlamydia pneumoniae), chemical stress (smoking, oxygen radicals, drugs), physical insult (heat, shear blood flow) and inflammation (inflammatory cytokines, lipopolysaccharide, oxidized low density lipoprotein, advanced glycation end products). In the present study, we show that increasing levels of sodium chloride can also induce an increase in intracellular and surface expression of HSP60 protein in human umbilical vein endothelial cells. In addition, we found that elevated sodium induces apoptosis.

Targeting inflammation to reduce cardiovascular disease risk: a realistic clinical prospect?

Data from basic science experiments is overwhelmingly supportive of the causal role of immune-inflammatory response(s) at the core of atherosclerosis, and therefore, the theoretical potential to manipulate the inflammatory response to prevent cardiovascular events. However, extrapolation to humans requires care and we still lack definitive evidence to show that interfering in immune-inflammatory processes may safely lessen clinical atherosclerosis. In this review, we discuss key therapeutic targets in the treatment of vascular inflammation, placing basic research in a wider clinical perspective, as well as identifying outstanding questions.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Atheroprotective vaccination with MHC-II-restricted ApoB peptides induces peritoneal IL-10-producing CD4 T cells

Although immunization with major histocompatibility complex (MHC) class II-restricted apolipoprotein B (ApoB) peptides has been shown to be atheroprotective, the mechanism is unclear. Here, we investigated CD4⁺ T cell populations in immunized atherosclerotic mice. Peptides (16-mers) from mouse ApoB, the core protein of low-density lipoprotein (LDL), were screened for binding to I-A^b by computer prediction and confirmed by radiolabeled peptide competition. Three new peptides, P101 (FGKQGFFPDSVNKALY, 5.5 nM IC₅₀), P102 (TLYALSHAVNSYFDVD, 6.8 nM), and P103 (LYYKEDKTSLSASAAS, 95 nM), were tested in an atherosclerosis model (Apoe^-/- mice on Western diet). Immunization with each of the three peptides (1 time in complete Freund's adjuvant subcuntaneously and 4 time in incomplete Freund's adjuvant intraperitoneally) but not with adjuvant alone showed significantly reduced atherosclerotic plaques in the aortic root by serial sections and in the whole aorta by en face staining. There were no differences in body weight, LDL cholesterol, or triglycerides. Peritoneal leukocytes from ApoB peptide-immunized mice, but not control mice, secreted significant amounts of IL-10 (150 pg/ml). Flow cytometry showed that peptide immunization induced IL-10 in 10% of peritoneal CD4⁺ T cells, some of which also expressed chemokine (C-C motif) receptor 5 (CCR5). Vaccination with ApoB peptides expanded peritoneal FoxP3⁺ regulatory CD4⁺ T cells and more than tripled the number of CCR5⁺FoxP3⁺ cells. Similar trends were also seen in the draining mediastinal lymph nodes but not in the nondraining inguinal lymph nodes. We conclude that vaccination with MHC class II-restricted autologous ApoB peptides induces regulatory T cells (Tregs) and IL-10, suggesting a plausible mechanism for atheroprotection.NEW & NOTEWORTHY Vaccination against apolipoprotein B (ApoB), the protein of LDL, attracts attention as a novel approach to prevent atherosclerosis. We discovered major histocompatibility complex class II-restricted ApoB peptides, which reduce atherosclerosis and induce IL-10-producing CD4⁺ T cells and chemokine (C-C motif) receptor 5 expression on regulatory T cells, suggesting that immunization with ApoB peptides inhibits atherosclerosis by inducing anti-inflammatory cytokines.

Protective and pathogenic roles of CD8+ T cells in atherosclerosis

Although infiltration of CD8⁺ T cells in human atherosclerotic lesions has been described 30 years ago, the role of these cells in lesion development has long remained enigmatic. While experimental models hinted at their pro-atherogenic role based on circumstantial evidence, genetic mouse models of cytotoxic CD8⁺ T cell-specific immune deficiency suggested no crucial role of these cells in lesion development. However, in recent years, more refined models of adoptive cell transfer, disruption of specific immune regulatory pathways or monoclonal antibody-mediated cell depletion have proposed both atheroprotective and pro-atherogenic functions for CD8⁺ T cells in atherosclerosis. In particular, MHC class I-restricted CD8⁺ T cell responses may protect from atherosclerosis, and Qa-1 restricted regulatory CD8⁺ T cells have been defined. In addition, regulatory CD8⁺CD25⁺ T cells possess atheroprotective properties. However, CD8⁺ T cells can also promote monopoiesis in hyperlipidemia, and exert prototypical cytotoxic functions to promote vascular inflammation and macrophage accumulation leading to atherosclerotic lesion development. Here, we review these findings, mostly from experimental studies that reveal a previously unrecognized complexity and important role of CD8⁺ T cells in atherosclerosis.

Triglyceride Treatment in the Age of Cholesterol Reduction

Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.

2015 Russell Ross Memorial Lecture in Vascular Biology: Protective Autoimmunity in Atherosclerosis

Atherosclerosis is an inflammatory disease of the arterial wall. It is accompanied by an autoimmune response against apolipoprotein B-100, the core protein of low-density lipoprotein, which manifests as CD4 T cell and antibody responses. To assess the role of the autoimmune response in atherosclerosis, the nature of the CD4 T cell response against apolipoprotein B-100 was studied with and without vaccination with major histocompatibility complex-II-restricted apolipoprotein B-100 peptides. The immunologic basis of autoimmunity in atherosclerosis is discussed in the framework of theories of adaptive immunity. Older vaccination approaches are also discussed. Vaccinating Apoe(-/-) mice with major histocompatibility complex-II-restricted apolipoprotein B-100 peptides reduces atheroma burden in the aorta by ≈40%. The protective mechanism likely includes secretion of interleukin-10. Protective autoimmunity limits atherosclerosis in mice and suggests potential for developing preventative and therapeutic vaccines for humans.

A potent multivalent vaccine for modulation of immune system in atherosclerosis: an in silico approach

Purpose

Atherosclerosis is classically defined as an immune-mediated disease characterized by accumulation of low-density lipoprotein cholesterol over intima in medium sized and large arteries. Recent studies have demonstrated that both innate and adaptive immune responses are involved in atherosclerosis. In addition, experimental and human models have recognized many autoantigens in pathophysiology of this disease. Oxidized low-density lipoproteins, β2 glycoprotein I (β-2-GPI), and heat shock protein 60 (HSP60) are the best studied of them which can represent promising approach to design worthwhile vaccines for modulation of atherosclerosis.

Materials and Methods

In silico approaches are the best tools for design and evaluation of the vaccines before initiating the experimental study. In this study, we identified immunogenic epitopes of HSP60, ApoB-100, and β-2-GPI as major antigens to construct a chimeric protein through bioinformatics tools. Additionally, we have evaluated physico-chemical properties, structures, stability, MHC binding properties, humoral and cellular immune responses, and allergenicity of this chimeric protein by means of bioinformatics tools and servers.

Results

Validation results indicated that 89.1% residues locate in favorite or additional allowed region of Ramachandran plot. Also, based on Ramachandran plot analysis this protein could be classified as a stable fusion protein. In addition, the epitopes in the chimeric protein had strong potential to induce both the B-cell and T-cell mediated immune responses.

Conclusion

Our results supported that this chimeric vaccine could be effectively utilized as a multivalent vaccine for prevention and modulation of atherosclerosis.

An apolipoprotein B100 mimotope prevents obesity in mice

Immunization with an ApoB100 mimotope prevents high-fat-diet-induced obesity in mice. Antibody titres parallel the weight decrements. In vitro data implicate increased lipolysis and reduced lipoprotein uptake by adipocytes, as well as increased uptake and metabolism of native lipoprotein by macrophages.

Although apolipoprotein B100 (ApoB100) plays a key role in peripheral fat deposition, it is not considered a suitable therapeutic target in obesity. In the present study we describe a novel ApoB100 mimotope, peptide pB1, and the use of pB1-based vaccine-like formulations (BVFs) against high-fat diet (HFD)-induced obesity. In HFD- compared with chow-fed adolescent mice, BVFs reduced the 3-month body-weight gains attributable to increased dietary fat by 44–65%, and prevented mesenteric fat accumulation and liver steatosis. The body-weight reductions paralleled the titres of pB1-reactive immunoglobulin G (IgG) antibodies, and pB1-reactive antibodies specifically recognized native ApoB100 and a synthetic peptide from the C-terminal half of ApoB100. In cultured 3T3L1 adipocytes, anti-pB1 antibodies increased lipolysis and inhibited low-density lipoprotein (LDL) uptake. In cultured RAW 264.7 macrophages, the same antibodies enhanced LDL uptake (without causing foam cell formation). These findings make ApoB100 a promising target for an immunization strategy against HFD-induced obesity.

Beyond vascular inflammation--recent advances in understanding atherosclerosis

Atherosclerosis is the most life-threatening pathology worldwide. Its major clinical complications, stroke, myocardial infarction, and heart failure, are on the rise in many regions of the world--despite considerable progress in understanding cause, progression, and consequences of atherosclerosis. Originally perceived as a lipid-storage disease of the arterial wall (Die cellularpathologie in ihrer begründung auf physiologische und pathologische gewebelehre. August Hirschwald Verlag Berlin, [1871]), atherosclerosis was recognized as a chronic inflammatory disease in 1986 (New Engl J Med 314:488-500, 1986). The presence of lymphocytes in atherosclerotic lesions suggested autoimmune processes in the vessel wall (Clin Exp Immunol 64:261-268, 1986). Since the advent of suitable mouse models of atherosclerosis (Science 258:468-471, 1992; Cell 71:343-353, 1992; J Clin Invest 92:883-893, 1993) and the development of flow cytometry to define the cellular infiltrate in atherosclerotic lesions (J Exp Med 203:1273-1282, 2006), the origin, lineage, phenotype, and function of distinct inflammatory cells that trigger or inhibit the inflammatory response in the atherosclerotic plaque have been studied. Multiphoton microscopy recently enabled direct visualization of antigen-specific interactions between T cells and antigen-presenting cells in the vessel wall (J Clin Invest 122:3114-3126, 2012). Vascular immunology is now emerging as a new field, providing evidence for protective as well as damaging autoimmune responses (Int Immunol 25:615-622, 2013). Manipulating inflammation and autoimmunity both hold promise for new therapeutic strategies in cardiovascular disease. Ongoing work (J Clin Invest 123:27-36, 2013; Front Immunol 2013; Semin Immunol 31:95-101, 2009) suggests that it may be possible to develop antigen-specific immunomodulatory prevention and therapy-a vaccine against atherosclerosis.