Abstract 21: A Natural Repertoire of T Cells Recognizing ApoB-100 is Generated Early in Life and is Progressively Depleted During Atherosclerotic Disease

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Dennis Wolf ◽  
Teresa Gerhardt ◽  
Jacqueline Miller ◽  
Sara McArdle ◽  
Takayuki Kimura ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Nodes ◽  
Mhc Class Ii ◽  
T Regulatory Cells ◽  
Low Density Lipoprotein ◽  
Large Body ◽  
Density Lipoprotein ◽  
Western Diet ◽  
Chow Diet ◽  
Progressive Loss

Background: A large body of evidence implicates a role for T cell driven auto-immunity in atherosclerosis. T cells in the atherosclerotic plaque specifically respond to auto-antigens, including ApoB-100, the main protein in low-density lipoprotein (LDL). However, existence, function, and location of auto-reactive T cells in mice have not been demonstrated. Methods and Results: We have previously identified several peptides derived from mouse ApoB-100 that bind with high affinity to the I-A b MHC class II molecule of C57BL/6 mice. Immunization with these peptides conferred atheroprotection. We designed a novel fluorochrome-labeled P6:I-A b multimer to detect T cells specifically recognizing this complex by flow cytometry. Surprisingly, we detected small numbers of P6:I-A b+ CD4 + T cells in young C57Bl/6 mice that reside in peripheral lymph nodes, indicating the existence of a small natural repertoire of P6:I-A b auto-reactive T cells. This repertoire of T cells was increased in atherosclerosis-prone A poe -/- and Ldlr -/- mice and showed signs of previous antigen-exposure in 4 week old animals. T cells recognizing P6:I-A b were undetectable directly after birth, but expanded rapidly within the first 28 days in lymph nodes. The majority of P6:I-A b+ T cells expressed the defining transcription factors of T H 1, T-bet, T H 17, ROR-gamma T, or of T-regulatory cells, FoxP3. Feeding of Apoe -/- mice with a western diet induced a further skew towards the T H 1 and T H 17 lineage, but also resulted in a progressive loss of antigen-specific cells over time. In Apoe -/- mice fed with a western diet for 1 year, but not in Apoe -/- mice fed with a standard chow diet, auto-reactive T cells disappeared. Mechanistically, we found enhanced expression of exhaustion markers like ICOS-1 or PD-1 in antigen-specific T cells likely due to persisting antigen-exposure in this model. Conclusion: Our findings indicate that T cells specifically recognizing a peptide derived from ApoB-100 do not expand during the natural course of disease, but instead exist in atherosclerosis-prone animals in early life. Chronic exposure to antigen induces a progressive loss of auto-reactive T cells.

Abstract 44: Failure of Protective Autoimmunity in Mouse and Human Atherosclerosis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Dennis Wolf ◽  
Teresa Gerhardt ◽  
Nathaly Anto Michel ◽  
Bjarke Hansen ◽  
Alessandro Sette ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Nodes ◽  
Mhc Class Ii ◽  
T Regulatory Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
T Cell Response ◽  
Regulatory Cells ◽  
Protective Autoimmunity

Background: In atherosclerosis, CD4 + T helper cells recognize auto-antigens including ApoB, the main protein in low-density lipoprotein (LDL). However, atherosclerosis-specific, auto-reactive CD4 + T cells have not been detected in vivo , and their function is unknown. Methods and Results: We have previously identified peptides derived from mouse ApoB that bind with high affinity to the MHC class II molecule of C57BL/6 mice (I-A b ). We designed and validated a new multimer of a recombinant MHC-II molecule fused to one ApoB auto-epitopes, P6 (TGAYSNASSTESASY, P6:I-A b ), that enabled detection of low-affinity, P6-reactive CD4 + T cells. Using this P6:I-A b multimer, we identified ApoB-reactive CD4 + T cells in healthy, young C57BL/6 mice that were predominately differentiated T-regulatory cells (T regs ) and expressed IL-10, a known atheroprotective cytokine. This population was detectable in lymph nodes and already showed a memory phenotype in young animals without atherosclerosis. In Apoe -/- mice, adoptively transferred ApoB P6-specific T regs accumulated in the aorta and draining lymph nodes and gave rise to pathogenic T H 1 and T H 17 cells. This phenotypic switch was caused by enhanced plasticity of antigen-specific T regs as evidenced by multiple clusters of intermediate T reg -T eff phenotypes in single cell RNA sequencing of 4485 antigen-specific CD4 + T cells. In the plaque, many T cells were ex-T regs as identified by a FoxP3 lineage tracker mouse, suggesting that atherosclerosis-specific CD4 + T cells lost their regulatory capacity. Vaccination with P6 maintained a protective phenotype in antigen-specific T regs and protected from atherosclerosis. In humans, ApoB-specific CD4 + T cells from atherosclerotic patients showed the same cytokine patterns found in mouse CD4 + T cells, suggesting that autoimmunity to ApoB is protective first, but later gives rise to a pathogenic CD4 + T cell response that aggravates atherosclerosis. Conclusion: Protective T-regulatory cells recognizing peptide antigens of ApoB exist in naïve mice, protect against atherosclerosis, but convert into pathogenic T H 1 and -17 cells during the natural course of disease in mice and humans. These results call for immunomodulatory therapies to maintain protective autoimmunity.

scholarly journals Inhibition of T cell response to native low-density lipoprotein reduces atherosclerosis

2010 ◽  
Vol 207 (5) ◽  
pp. 1081-1093 ◽  
Author(s):  
Andreas Hermansson ◽  
Daniel F.J. Ketelhuth ◽  
Daniela Strodthoff ◽  
Marion Wurm ◽  
Emil M. Hansson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
T Cell Responses ◽  
Class Ii ◽  
Low Density ◽  
Cell Responses ◽  
Ldl Particles

Immune responses to oxidized low-density lipoprotein (oxLDL) are proposed to be important in atherosclerosis. To identify the mechanisms of recognition that govern T cell responses to LDL particles, we generated T cell hybridomas from human ApoB100 transgenic (huB100tg) mice that were immunized with human oxLDL. Surprisingly, none of the hybridomas responded to oxidized LDL, only to native LDL and the purified LDL apolipoprotein ApoB100. However, sera from immunized mice contained IgG antibodies to oxLDL, suggesting that T cell responses to native ApoB100 help B cells making antibodies to oxLDL. ApoB100 responding CD4+ T cell hybridomas were MHC class II–restricted and expressed a single T cell receptor (TCR) variable (V) β chain, TRBV31, with different Vα chains. Immunization of huB100tgxLdlr−/− mice with a TRBV31-derived peptide induced anti-TRBV31 antibodies that blocked T cell recognition of ApoB100. This treatment significantly reduced atherosclerosis by 65%, with a concomitant reduction of macrophage infiltration and MHC class II expression in lesions. In conclusion, CD4+ T cells recognize epitopes on native ApoB100 protein, this response is associated with a limited set of clonotypic TCRs, and blocking TCR-dependent antigen recognition by these T cells protects against atherosclerosis.

scholarly journals Autoimmune Regulator (AIRE) Deficiency Does Not Affect Atherosclerosis and CD4 T Cell Immune Tolerance to Apolipoprotein B

2022 ◽  
Vol 8 ◽  
Author(s):  
Felix Sebastian Nettersheim ◽  
Simon Braumann ◽  
Kouji Kobiyama ◽  
Marco Orecchioni ◽  
Melanie Vassallo ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Tolerance ◽  
Low Density Lipoprotein ◽  
Adaptive Immune Response ◽  
Density Lipoprotein ◽  
Chow Diet ◽  
Structural Protein ◽  
Autoimmune Regulator ◽  
And Gender ◽  
Underlying Mechanisms

Atherosclerosis is a chronic, lipid-driven disease of medium sized arteries which causes myocardial infarction and stroke. Recently, an adaptive immune response against the plaque-associated autoantigen Apolipoprotein B100 (ApoB), the structural protein component of low-density lipoprotein, has been implicated in atherogenesis. In healthy individuals, CD4+ T cells responding to ApoB mainly comprised regulatory T cells, which confer immune tolerance and atheroprotection. Mice and patients with atherosclerosis harbor increased numbers of proatherogenic ApoB-reactive T-helper cell subsets. Given the lack of therapies targeting proatherogenic immunity, clarification of the underlying mechanisms is of high clinical relevance. T cells develop in the thymus, where strong autoreactive T cells are eliminated in the process of negative selection. Herein, we investigated whether the transcription factor autoimmune regulator (AIRE), which controls expression of numerous tissue-restricted self-antigens in the thymus, is involved in mediating tolerance to ApoB and whether Aire deficiency might contribute to atherogenesis. Mice deficient for Aire were crossbred to apolipoprotein E-deficient mice to obtain atherosclerosis-prone Aire−/−Apoe−/− mice, which were fed a regular chow diet (CD) or western-type diet (WD). CD4+ T cells responding to the ApoB peptide p6 were analyzed by flow cytometry. We demonstrate that Aire deficiency influences neither generation nor activation of ApoB-reactive T cells and has only minor and overall inconsistent impacts on their phenotype. Furthermore, we show that atherosclerotic plaque size is not affected in Aire−/−Apoe−/− compared to Aire+/+Apoe−/−, irrespective of diet and gender. In conclusion, our data suggests that AIRE is not involved in regulating thymic expression of ApoB or atherosclerosis. Alternative mechanisms how ApoB-reactive CD4 T cells are selected in the thymus will have to be investigated.

scholarly journals Platelet CD36 signaling through ERK5 promotes caspase-dependent procoagulant activity and fibrin deposition in vivo

2018 ◽  
Vol 2 (21) ◽  
pp. 2848-2861 ◽  
Author(s):  
Moua Yang ◽  
Andaleb Kholmukhamedov ◽  
Marie L. Schulte ◽  
Brian C. Cooley ◽  
Na’il O. Scoggins ◽  
...  
Keyword(s):  
Platelet Reactivity ◽  
Low Density Lipoprotein ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Signaling Molecules ◽  
Chow Diet ◽  
Glycoprotein Vi ◽  
Platelet Signaling ◽  
Clinically Significant

Abstract Dyslipidemia is a risk factor for clinically significant thrombotic events. In this condition, scavenger receptor CD36 potentiates platelet reactivity through recognition of circulating oxidized lipids. CD36 promotes thrombosis by activating redox-sensitive signaling molecules, such as the MAPK extracellular signal-regulated kinase 5 (ERK5). However, the events downstream of platelet ERK5 are not clear. In this study, we report that oxidized low-density lipoprotein (oxLDL) promotes exposure of procoagulant phosphatidylserine (PSer) on platelet surfaces. Studies using pharmacologic inhibitors indicate that oxLDL-CD36 interaction–induced PSer exposure requires apoptotic caspases in addition to the downstream CD36-signaling molecules Src kinases, hydrogen peroxide, and ERK5. Caspases promote PSer exposure and, subsequently, recruitment of the prothrombinase complex, resulting in the generation of fibrin from the activation of thrombin. Caspase activity was observed when platelets were stimulated with oxLDL. This was prevented by inhibiting CD36 and ERK5. Furthermore, oxLDL potentiates convulxin/glycoprotein VI–mediated fibrin formation by platelets, which was prevented when CD36, ERK5, and caspases were inhibited. Using 2 in vivo arterial thrombosis models in apoE-null hyperlipidemic mice demonstrated enhanced arterial fibrin accumulation upon vessel injury. Importantly, absence of ERK5 in platelets or mice lacking CD36 displayed decreased fibrin accumulation in high-fat diet–fed conditions comparable to that seen in chow diet–fed animals. These findings suggest that platelet signaling through CD36 and ERK5 induces a procoagulant phenotype in the hyperlipidemic environment by enhancing caspase-mediated PSer exposure.

Abstract 566: MicroRNA-146a Deficiency Prevents PCSK9 Gain-of-Function Mutation-induced Hypercholesterolemia in Mice

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Shayan Mohammadmoradi ◽  
Aida Javidan ◽  
Weihua Jiang ◽  
Jessica Moorleghen ◽  
Venkateswaran Subramanian
Keyword(s):  
Plasma Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Western Diet ◽  
Size Exclusion ◽  
Gel Chromatography ◽  
Low Density ◽  
Distribution Analysis ◽  
Gain Of Function ◽  
Ldl Particles

Background and Objective: Mimetic mediated activation of microRNA 146a (miR-146a) reduces atherosclerosis via suppression of nuclear factor-κB-driven inflammation in mice. The purpose of this study was to determine whether miR-146a influences plasma cholesterol in hypercholesterolemic mice. Methods and Results: To induce hypercholesterolemia, female C57BL/6 miR-146a WT (n=8) and miR-146a KO (n=8) mice were injected intraperitoneally with an adeno-associated viral vector (AAV) expressing the proprotein convertase subtilisin/kexin type 9 (PSCK9 D377Y) gain-of-function mutant at a dose of 3 x 10 10 genomic copies/mouse. After infection, mice were fed a Western diet (21% wt/wt milk fat; 0.15% wt/wt cholesterol) for sixteen weeks, and plasma PCSK9 and total cholesterol concentrations were monitored monthly using an enzymatic assay. Plasma PCSK9 concentrations were profoundly increased 4 weeks post injection (Baseline: WT - 179 ± 12 vs KO - 207 ± 12; Week 4: WT - 1700 ± 148 vs KO - 2689 ± 305 ng/ml) and remained significantly high during 16 weeks (WT - 882 ± 142 vs KO - 718 ± 109 ng/ml; p<0.05 vs baseline) of Western diet feeding. Consistent with increased plasma PCSK9 concentrations, plasma cholesterol concentrations were increased in both groups of mice. Interestingly, miR-146a KO group mice showed less significant increase in plasma cholesterol compared to WT group (Baseline: WT - 88 ± 3 vs KO - 83 ± 3; Week 4: WT - 328 ± 25 vs KO - 195 ± 18 mg/dl) irrespective of the comparable plasma PCSK9 concentrations. Also, lipoprotein distribution analysis with size exclusion gel chromatography revealed that miR-146a KO mice showed a strong reduction in high density lipoprotein (HDL) particles while very low density lipoprotein (VLDL) and low density lipoprotein (LDL) particles were not affected. Conclusion: Our findings suggests that miR146a plays a critical role in the regulation of HDL particles in PCSK9 gain-of-function mutant-induced hypercholesterolemia in mice. Future studies will identify gene targets influenced by miR-146a in regulating HDL-cholesterol in hypercholesterolemic mice.

Western diet in the perinatal period promotes dysautonomia in the offspring of adult rats

2016 ◽  
Vol 8 (2) ◽  
pp. 216-225 ◽  
Author(s):  
R. Vidal-Santos ◽  
F. N. Macedo ◽  
M. N. S. Santana ◽  
V. U. De Melo ◽  
J. L. de Brito Alves ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Systolic Arterial Pressure ◽  
Perinatal Period ◽  
Western Diet ◽  
Control Group ◽  
Standard Diet ◽  
Adult Rats ◽  
Male Wistar Rats ◽  
The Impact

The present study investigated the impact of a western diet during gestation and lactation on the anthropometry, serum biochemical, blood pressure and cardiovascular autonomic control on the offspring. Male Wistar rats were divided into two groups according to their mother’s diet received: control group (C: 18% calories of lipids) and westernized group (W: 32% calories of lipids). After weaning both groups received standard diet. On the 60th day of life, blood samples were collected for the analysis of fasting glucose and lipidogram. Cardiovascular parameters were measured on the same period. Autonomic nervous system modulation was evaluated by spectrum analysis of heart rate (HR) and systolic arterial pressure (SAP). The W increased glycemia (123±2v. 155±2 mg/dl), low-density lipoprotein (15±1v. 31±2 mg/dl), triglycerides (49±1v. 85±2 mg/dl), total cholesterol (75±2v. 86±2 mg/dl), and decreased high-density lipoprotein (50±4v. 38±3 mg/dl), as well as increased body mass (209±4v. 229±6 g) than C. Furthermore, the W showed higher SAP (130±4v. 157±2 mmHg), HR (357±10v. 428±14 bpm), sympathetic modulation to vessels (2.3±0.56v. 6±0.84 mmHg2) and LF/HF ratio (0.15±0.01v. 0.7±0.2) than C. These findings suggest that a western diet during pregnancy and lactation leads to overweight associated with autonomic misbalance and hypertension in adulthood.

scholarly journals Oxidized low-density lipoproteins induce tissue factor expression in T-lymphocytes via activation of lectin-like oxidized low-density lipoprotein receptor-1

2019 ◽  
Vol 116 (6) ◽  
pp. 1125-1135 ◽  
Author(s):  
Giovanni Cimmino ◽  
Plinio Cirillo ◽  
Stefano Conte ◽  
Grazia Pellegrino ◽  
Giusi Barra ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Ros Generation ◽  
Low Density ◽  
Dependent Manner ◽  
Cd8 Cells ◽  
Human Carotid

Abstract Aims T-lymphocytes plays an important role in the pathophysiology of acute coronary syndromes. T-cell activation in vitro by pro-inflammatory cytokines may lead to functional tissue factor (TF) expression, indicating a possible contribution of immunity to thrombosis. Oxidized low-density lipoproteins (oxLDLs) are found abundantly in atherosclerotic plaques. We aimed at evaluating the effects of oxLDLs on TF expression in T cells and the role of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). Methods and results CD3+ cells were isolated from healthy volunteers. Gene, protein, and surface expression of TF, as well as of LOX-1, were assessed at different time-points after oxLDL stimulation. To determine whether oxLDL-induced TF was LOX-1 dependent, T cells were pre-incubated with an LOX-1 inhibiting peptide (L-RBP) or with an anti-LOX-1 blocking antibody. To exclude that TF expression was mediated by reactive oxygen species (ROS) generation, oxLDL-stimulated T cells were pre-incubated with superoxide dismutase + catalase or with 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), an intracellular free radical scavenger. Finally, to determine if the observed findings in vitro may have a biological relevance, the presence of CD3+/TF+/LOX-1+ cells was evaluated by immunofluorescence in human carotid atherosclerotic lesions. oxLDLs induced functionally active TF expression in T cells in a dose- and time-dependent manner, independently on ROS generation. No effect was observed in native LDL-treated T cells. LOX-1 expression was also induced by oxLDLs in a time- and dose-dependent manner. Pre-incubation with L-RBP or anti-LOX-1 antibody almost completely inhibited oxLDL-mediated TF expression. Interestingly, human carotid plaques showed significant infiltration of CD3+ cells (mainly CD8+ cells), some of which were positive for both TF and LOX-1. Conclusion oxLDLs induce functional TF expression in T-lymphocytes in vitro via interaction of oxLDLs with LOX-1. Human carotid atherosclerotic plaques contain CD3+/CD8+cells that express both TF and LOX-1, indicating that also in patients these mechanisms may play an important role.

scholarly journals Adaptive Immune Responses in Human Atherosclerosis

2020 ◽  
Vol 21 (23) ◽  
pp. 9322
Author(s):  
Silvia Lee ◽  
Benjamin Bartlett ◽  
Girish Dwivedi
Keyword(s):  
T Cells ◽  
Low Density Lipoprotein ◽  
Clinical Manifestations ◽  
Density Lipoprotein ◽  
Chronic Inflammatory Disease ◽  
Th2 Cells ◽  
Low Density ◽  
Heat Shock Protein 60 ◽  
Atherosclerosis Progression ◽  
Human Atherosclerosis

Atherosclerosis is a chronic inflammatory disease that is initiated by the deposition and accumulation of low-density lipoproteins in the artery wall. In this review, we will discuss the role of T- and B-cells in human plaques at different stages of atherosclerosis and the utility of profiling circulating immune cells to monitor atherosclerosis progression. Evidence supports a proatherogenic role for intraplaque T helper type 1 (Th1) cells, CD4+CD28null T-cells, and natural killer T-cells, whereas Th2 cells and regulatory T-cells (Treg) have an atheroprotective role. Several studies indicate that intraplaque T-cells are activated upon recognition of endogenous antigens including heat shock protein 60 and oxidized low-density lipoprotein, but antigens derived from pathogens can also trigger T-cell proliferation and cytokine production. Future studies are needed to assess whether circulating cellular biomarkers can improve identification of vulnerable lesions so that effective intervention can be implemented before clinical manifestations are apparent.

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