Antigen-presenting dendritic cells in atherosclerosis

Apolipoprotein B-containing lipoproteins in atherogenesis

Apolipoprotein B (apoB) is the main structural protein of LDLs, triglyceride-rich lipoproteins and lipoprotein(a), and is crucial for their formation, metabolism and atherogenic properties. In this Review, we present insights into the role of apoB-containing lipoproteins in atherogenesis, with an emphasis on the mechanisms leading to plaque initiation and growth. LDL, the most abundant cholesterol-rich lipoprotein in plasma, is causally linked to atherosclerosis. LDL enters the artery wall by transcytosis and, in vulnerable regions, is retained in the subendothelial space by binding to proteoglycans via specific sites on apoB. A maladaptive response ensues. This response involves modification of LDL particles, which promotes LDL retention and the release of bioactive lipid products that trigger inflammatory responses in vascular cells, as well as adaptive immune responses. Resident and recruited macrophages take up modified LDL, leading to foam cell formation and ultimately cell death due to inadequate cellular lipid handling. Accumulation of dead cells and cholesterol crystallization are hallmarks of the necrotic core of atherosclerotic plaques. Other apoB-containing lipoproteins, although less abundant, have substantially greater atherogenicity per particle than LDL. These lipoproteins probably contribute to atherogenesis in a similar way to LDL but might also induce additional pathogenic mechanisms. Several targets for intervention to reduce the rate of atherosclerotic lesion initiation and progression have now been identified, including lowering plasma lipoprotein levels and modulating the maladaptive responses in the artery wall.

Investigating the landscape of immune-related genes and immunophenotypes in atherosclerosis: A bioinformatics Mendelian randomization study

BACKGROUND

Atherosclerosis, a leading cause of cardiovascular disease, is characterized by intricate interactions among lipid metabolism, inflammation, and immune response. Investigating immune-related genetic factors and immune cell infiltration in atherosclerotic tissues may provide insights into potential therapeutic targets.

METHODS

We analyzed transcriptomic data from atherosclerotic and normal tissues to identify differentially expressed genes (DEGs). Functional enrichment was performed using KEGG and GO pathway analyses, and immune-related DEGs were identified by intersecting DEGs with immune-related gene sets. Mendelian randomization (MR) was utilized to examine the causal relationship between immune-related DEGs and atherosclerosis. Immune cell infiltration was evaluated using Cibersort, MCP-counter, and xCell. Again, MR was performed to assess the causal effects of 731 immunophenotypes on atherosclerosis.

RESULTS

A total of 428 DEGs were identified between atherosclerotic and normal tissues, of which 112 were immune-related. Immune cell infiltration analysis highlighted significant differences, particularly in CD8 T cells and B cells. MR analysis demonstrated a significant causal relationship between HLA-DR on dendritic cells (OR [95%CI] =1.04[1.02-1.06], p = 1.03e-5) and coronary atherosclerosis. Furthermore, HLA-DR on myeloid dendritic cells (OR [95%CI] =1.12[1.07-1.17], p = 3.13e-06) and CD8 on CD8+ T cells (OR [95%CI] =1.12[1.05-1.18], p = 2.00e-04) were causally linked to atherosclerosis (excluding cerebral, coronary, and PAD).

CONCLUSION

Our findings highlight the crucial involvement of immune-related DEGs and specific immune cell types in the development of atherosclerosis. These results suggest that targeting immune pathways, particularly HLA DR on dendritic cells and CD8 on CD8+ T cells, may offer promising therapeutic strategies for atherosclerosis.

Resveratrol promotes cholesterol efflux from dendritic cells and controls costimulation and T-cell activation in high-fat and lipopolysaccharide-driven atherosclerotic mice

Cholesterol aggregation in dendritic cells (DCs) triggers an inflammatory response and accelerates the development of atherosclerosis (AS). Resveratrol (RES), a natural compound with anti-inflammatory and cholesterol metabolism regulatory properties, has been shown to influence the maturation and inflammatory functions of DCs. However, its relationship with cholesterol metabolism remains unclear. This study aimed to explore the roles of RES in cholesterol metabolism and inflammatory behaviors of DCs in the context of AS. We analyzed the effect of RES on cholesterol efflux from ApoE-/- bone marrow-derived dendritic cells (BMDCs) using qRT-PCR, Western blot, and cholesterol efflux assays; identified the inflammatory status of RES-treated BMDCs and co-cultured T cells using flow cytometry and ELISA; confirmed the effect of RES on blood lipids, atherosclerotic lesions, cholesterol metabolism, and inflammatory response in high-fat diet and lipopolysaccharide-treated ApoE-/- mice; and explored the potential targets of RES in regulating inflammatory behavior via molecular docking. The results revealed that RES promotes cholesterol efflux, increases the expression of efflux transporter ABCA1, and decreases liver X receptor alpha (LXRα) expression in response to a decrease in intracellular cholesterol in ApoE-/- BMDCs. RES also reduced MHC-II+ cells and downregulated costimulatory molecule CD80 in BMDCs with decreased IL-6 and increased IL-2 production, and suppressed T-cell activation and modulates IL-22 and IL-10 secretion via BMDCs. Furthermore, we confirmed that RES relieves arterial lesions and regulates blood lipids in ApoE-/- mice. RES demonstrated ABCA1 upregulation and LXRα downregulation effects in the aorta and regulated costimulation molecules and Th17/Treg cytokines in the spleen. Furthermore, RES showed multiple hydrogen bonding and low binding energy with ABCA1, suggesting that ABCA1 is a potential target of RES to modulate the inflammatory properties of BMDCs. Our study demonstrated that RES regulates cholesterol efflux and inflammatory behavior in BMDCs, contributing to the control of AS progression and offering new insights for managing inflammatory diseases.

RBC-hitchhiking PLGA nanoparticles loading β-glucan as a delivery system to enhance in vitro and in vivo immune responses in mice

Red blood cells (RBCs) naturally trap some bacterial pathogens in the circulation and kill them by oxidative stress. Following neutralization, the bacteria are presented to antigen-presenting cells in the spleen by the RBCs. This ability of RBCs has been harnessed to develop a system where they play a crucial role in enhancing the immune response, offering a novel approach to enhance the body's immunity. In this work, a conjugate, G-OVA, was formed by connecting β-glucan and OVA through a disulfide bond. Poly (lactic-co-glycolic acid) (PLGA) was then employed to encapsulate G-OVA, yielding G-OVA-PLGA. Finally, the nanoparticles were adsorbed onto RBCs to develop G-OVA-PLGA@RBC. The results demonstrated that the delivery of nanoparticles by RBCs enhanced the antibody response to antigens both in vitro and in vivo. The objective of this study was to investigate the increased immune activity of G-OVA-PLGA nanoparticles facilitated by RBCs transportation and to elucidate some of its underlying mechanisms. These findings are anticipated to contribute valuable insights for the development of efficient and safe immune enhancers.

CCL22 Induces the Polarization of Immature Dendritic Cells into Tolerogenic Dendritic Cells in Radiation-Induced Lung Injury through the CCR4-Dectin2-PLC-γ2-NFATC2-Nr4a2-PD-L1 Signaling Pathway

Recruitment of immune cells to the injury site plays a pivotal role in the pathology of radiation-associated diseases. In this study, we investigated the impact of the chemokine CCL22 released from alveolar type II epithelial (AT2) cells after irradiation on the recruitment and functional changes of dendritic cells (DCs) in the development of radiation-induced lung injury (RILI). By examining changes in CCL22 protein levels in lung tissue of C57BL/6N mice with RILI, we discovered that ionizing radiation increased CCL22 expression in irradiated alveolar AT2 cells, as did MLE-12 cells after irradiation. A transwell migration assay revealed that CCL22 promoted the migration of CCR4-positive DCs to the injury site, which explained the migration of pulmonary CCR4-positive DCs in RILI mice in vivo. Coculture experiments demonstrated that, consistent with the response of regulatory T cells in the lung tissue of RILI mice, exogenous CCL22-induced DCs promoted regulatory T cell proliferation. Mechanistically, we demonstrated that Dectin2 and Nr4a2 are key targets in the CCL22 signaling pathway, which was confirmed in pulmonary DCs of RILI mice. As a result, CCL22 upregulated the expression of PD-L1, IL-6, and IL-10 in DCs. Consequently, we identified a mechanism in which CCL22 induced DC tolerance through the CCR4-Dectin2-PLC-γ2-NFATC2-Nr4a2-PD-L1 pathway. Collectively, these findings demonstrated that ionizing radiation stimulates the expression of CCL22 in AT2 cells to recruit DCs to the injury site and further polarizes them into a tolerant subgroup of CCL22 DCs to regulate lung immunity, ultimately providing potential therapeutic targets for DC-mediated RILI.

Identification of Endoplasmic Reticulum Stress-Related Biomarkers in Coronary Artery Disease

Coronary artery disease (CAD) is caused by atherosclerotic lesions in the coronary vessels. Endoplasmic reticulum stress (ERS) acts in cardiovascular disease, and its role in CAD is not clear. A total of 13 differentially expressed ERS-related genes (DEERSRGs) in CAD were identified. Functional enrichment analysis demonstrated the DEERSRGs were mainly enriched in endoplasmic reticulum (ER)-related pathways. Then, eight genes (RCN2, HRC, DERL2, RNF183, CRH, TMED2, PPP1R15A, and IL1A) were authenticated as ERS-related biomarkers in CAD by least absolute shrinkage and selection operator (LASSO). The receiver operating characteristic (ROC) analysis showed that the LASSO logistic model constructed based on biomarkers had a better diagnostic effect, which was confirmed by the ANN and GSE23561 datasets. Also, ROC results showed that seven of the eight biomarkers had better diagnostic effects. The nomogram model had good predictive power, and biomarkers were mostly enriched in pathways associated with CAD. The biomarkers were significantly associated with 10 immune cells, and RCN2, DERL2, TMED2, and RNF183 were negatively correlated with most chemokines. Eight biomarkers had significant correlations with both immunoinhibitors and immunostimulators. In addition, eight biomarkers were significantly different in both CAD and control samples, CRH and HRC were upregulated in CAD. The quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed that RCN2, HRC, DERL2, CRH, and IL1A were consistent with the bioinformatics analysis. RCN2, HRC, DERL2, RNF183, CRH, TMED2, PPP1R15A, and IL1A were identified as biomarkers of CAD. Functional enrichment analysis and immunoassays for biomarkers provide new ideas for the treatment of CAD.

The mitochondria-targeted antioxidant MitoQ ameliorates inorganic arsenic-induced DCs/Th1/Th2/Th17/Treg differentiation partially by activating PINK1-mediated mitophagy in murine liver

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.

Regulation of vascular remodeling by immune microenvironment after the establishment of autologous arteriovenous fistula in ESRD patients

Autogenous arteriovenous fistula (AVF) is the preferred dialysis access for receiving hemodialysis treatment in end-stage renal disease patients. After AVF is established, vascular remodeling occurs in order to adapt to hemodynamic changes. Uremia toxins, surgical injury, blood flow changes and other factors can induce inflammatory response, immune microenvironment changes, and play an important role in the maintenance of AVF vascular remodeling. This process involves the infiltration of pro-inflammatory and anti-inflammatory immune cells and the secretion of cytokines. Pro-inflammatory and anti-inflammatory immune cells include neutrophil (NEUT), dendritic cell (DC), T lymphocyte, macrophage (Mφ), etc. This article reviews the latest research progress and focuses on the role of immune microenvironment changes in vascular remodeling of AVF, in order to provide a new theoretical basis for the prevention and treatment of AVF failure.

Caught in action: how MSCs modulate atherosclerotic plaque

Atherosclerosis (AS) is a medical condition marked by the stiffening and constriction of the arteries. This is caused by the accumulation of plaque, a substance made up of fat, cholesterol, calcium, and other elements present in the blood. Over time, this plaque solidifies and constricts the arteries, restricting the circulation of oxygen-rich blood to the organs and other body parts. The onset and progression of AS involve a continuous inflammatory response, including the infiltration of inflammatory cells, foam cells derived from monocytes/macrophages, and inflammatory cytokines and chemokines. Mesenchymal stromal cells (MSCs), a type of multipotent stem cells originating from various body tissues, have recently been demonstrated to have a protective and regulatory role in diseases involving inflammation. Consequently, the transplantation of MSCs is being proposed as a novel therapeutic strategy for atherosclerosis treatment. This mini-review intends to provide a summary of the regulatory effects of MSCs at the plaque site to lay the groundwork for therapeutic interventions.

Identification of a non-canonical chemokine-receptor pathway suppressing regulatory T cells to drive atherosclerosis

CCL17 is produced by conventional dendritic cells (cDCs), signals through CCR4 on regulatory T cells (Tregs), and drives atherosclerosis by suppressing Treg functions through yet undefined mechanisms. Here we show that cDCs from CCL17-deficient mice display a pro-tolerogenic phenotype and transcriptome that is not phenocopied in mice lacking its cognate receptor CCR4. In the plasma of CCL17-deficient mice, CCL3 was the only decreased cytokine/chemokine. We found that CCL17 signaled through CCR8 as an alternate high-affinity receptor, which induced CCL3 expression and suppressed Treg functions in the absence of CCR4. Genetic ablation of CCL3 and CCR8 in CD4+ T cells reduced CCL3 secretion, boosted FoxP3+ Treg numbers, and limited atherosclerosis. Conversely, CCL3 administration exacerbated atherosclerosis and restrained Treg differentiation. In symptomatic versus asymptomatic human carotid atheroma, CCL3 expression was increased, while FoxP3 expression was reduced. Together, we identified a non-canonical chemokine pathway whereby CCL17 interacts with CCR8 to yield a CCL3-dependent suppression of atheroprotective Tregs.

LncRNA/CircRNA-miRNA-mRNA Axis in Atherosclerotic Inflammation: Research Progress

Atherosclerosis is characterized by chronic inflammation of the arterial wall. However, the exact mechanism underlying atherosclerosis-related inflammation has not been fully elucidated. To gain insight into the mechanisms underlying the inflammatory process that leads to atherosclerosis, there is need to identify novel molecular markers. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-protein-coding RNAs (lncRNAs) and circular RNAs (circRNAs) have gained prominence in recent years. LncRNAs/circRNAs act as competing endogenous RNAs (ceRNAs) that bind to miRNAs via microRNA response elements (MREs), thereby inhibiting the silencing of miRNA target mRNAs. Inflammatory mediators and inflammatory signaling pathways are closely regulated by ceRNA regulatory networks in atherosclerosis. In this review, we discuss the role of LncRNA/CircRNA-miRNA-mRNA axis in atherosclerotic inflammation and how it can be targeted for early clinical detection and treatment.

Role of neutrophil extracellular trap and immune infiltration in atherosclerotic plaque instability: Novel insight from bioinformatics analysis and machine learning

The instability of atherosclerotic plaques increases the risk of acute coronary syndrome. Neutrophil extracellular traps (NETs), mesh-like complexes consisting of extracellular DNA adorned with various protein substances, have been recently discovered to play an essential role in atherosclerotic plaque formation and development. This study aimed to investigate novel diagnostic biomarkers that can identify unstable plaques for early distinction and prevention of plaque erosion or disruption. Differential expression analysis was used to identify the differentially expressed NET-related genes, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed. We filtered the characteristic genes using machine learning and estimated diagnostic efficacy using receiver operating characteristic curves. Immune infiltration was detected using single-sample gene set enrichment analysis and the biological signaling pathways involved in characteristic genes utilizing gene set enrichment analysis were explored. Finally, miRNAs- and transcription factors-target genes networks were established. We identified 8 differentially expressed NET-related genes primarily involved in immune-related pathways. Four were identified as capable of distinguishing unstable plaques. More immune cells infiltrated unstable plaques than stable plaques, and these cells were predominantly positively related to characteristic genes. These 4 diagnostic genes are involved in immune responses and the modulation of smooth muscle contractility. Several miRNAs and transcription factors were predicted as upstream regulatory factors, providing further information on the identification and prevention of atherosclerotic plaques rupture. We identified several promising NET-related genes (AQP9, C5AR1, FPR3, and SIGLEC9) and immune cell subsets that may identify unstable atherosclerotic plaques at an early stage and prevent various complications of plaque disruption.

Natural Monoterpenes as Potential Therapeutic Agents against Atherosclerosis

Traditional herbal medicines based on natural products play a pivotal role in preventing and managing atherosclerotic diseases, which are among the leading causes of death globally. Monoterpenes are a large class of naturally occurring compounds commonly found in many aromatic and medicinal plants. Emerging evidence has shown that monoterpenes have many biological properties, including cardioprotective effects. Remarkably, an increasing number of studies have demonstrated the therapeutic potential of natural monoterpenes to protect against the pathogenesis of atherosclerosis. These findings shed light on developing novel effective antiatherogenic drugs from these compounds. Herein, we provide an overview of natural monoterpenes' effects on atherogenesis and the underlying mechanisms. Monoterpenes have pleiotropic and multitargeted pharmacological properties by interacting with various cell types and intracellular molecular pathways involved in atherogenesis. These properties confer remarkable advantages in managing atherosclerosis, which has been recognized as a multifaceted vascular disease. We also discuss limitations in the potential clinical application of monoterpenes as therapeutic agents against atherosclerosis. We propose perspectives to give new insights into future preclinical research and clinical practice regarding natural monoterpenes.

Pathophysiology of Inflammatory Bowel Disease: Innate Immune System

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation with no exact known cause. Intestinal innate immunity is enacted by neutrophils, monocytes, macrophages, and dendritic cells (DCs), and innate lymphoid cells and NK cells, characterized by their capacity to produce a rapid and nonspecific reaction as a first-line response. Innate immune cells (IIC) defend against pathogens and excessive entry of intestinal microorganisms, while preserving immune tolerance to resident intestinal microbiota. Changes to this equilibrium are linked to intestinal inflammation in the gut and IBD. IICs mediate host defense responses, inflammation, and tissue healing by producing cytokines and chemokines, activating the complement cascade and phagocytosis, or presenting antigens to activate the adaptive immune response. IICs exert important functions that promote or ameliorate the cellular and molecular mechanisms that underlie and sustain IBD. A comprehensive understanding of the mechanisms underlying these clinical manifestations will be important for developing therapies targeting the innate immune system in IBD patients. This review examines the complex roles of and interactions among IICs, and their interactions with other immune and non-immune cells in homeostasis and pathological conditions.

Advances in immunotherapy modalities for atherosclerosis

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. Atherosclerosis is the pathological basis of atherosclerotic cardiovascular disease (ASCVD). Atherosclerosis is now understood to be a long-term immune-mediated inflammatory condition brought on by a complicated chain of factors, including endothelial dysfunction, lipid deposits in the artery wall, and monocyte-derived macrophage infiltration, in which both innate immunity and adaptive immunity play an indispensable role. Recent studies have shown that atherosclerosis can be alleviated by inducing a protective immune response through certain auto-antigens or exogenous antigens. Some clinical trials have also demonstrated that atherosclerotic is associated with the presence of immune cells and immune factors in the body. Therefore, immunotherapy is expected to be a new preventive and curative measure for atherosclerosis. In this review, we provide a summary overview of recent progress in the research of immune mechanisms of atherosclerosis and targeted therapeutic pathways.

Identification of diagnostic biomarkers and therapeutic targets in peripheral immune landscape from coronary artery disease

Background

Peripheral biomarkers are increasingly vital non-invasive methods for monitoring coronary artery disease (CAD) progression. Their superiority in early detection, prognosis evaluation and classified diagnosis is becoming irreplaceable. Nevertheless, they are still less explored. This study aimed to determine and validate the diagnostic and therapeutic values of differentially expressed immune-related genes (DE-IRGs) in CAD.

Methods

We downloaded clinical information and RNA sequence data from the GEO database. We used R software, GO, KEGG and Cytoscape to analyze and visualize the data. A LASSO method was conducted to identify key genes for diagnostic model construction. The ssGSEA analysis was used to investigate the differential immune cell infiltration. Besides, we constructed CAD mouse model (low-density lipoprotein receptor deficient mice with high fat diet) to discover the correlation between the screened genes and severe CAD progress. We further uncovered the role of IL13RA1 might play in atherosclerosis.

Results

A total of 762 differential genes were identified between the peripheral blood of 218 controls and 199 CAD patients, which were significantly associated with infection, immune response and neural activity. 58 DE-IRGs were obtained by overlapping the differentially expressed genes(DEGs) and immune-related genes downloaded from ImmpDb database. Through LASSO regression, CCR9, CER1, CSF2, IL13RA1, INSL5, MBL2, MMP9, MSR1, NTS, TNFRSF19, CXCL2, HTR3C, IL1A, and NR4A2 were distinguished as peripheral biomarkers of CAD with eligible diagnostic capabilities in the training set (AUC = 0.968) and test set (AUC = 0.859). The ssGSEA analysis showed that the peripheral immune cells had characteristic distribution in CAD and also close relationship with specific DE-IRGs. RT-qPCR test showed that CCR9, CSF2, IL13RA1, and NTS had a significant correlation with LDLR^−/− mice. IL13RA1 knocked down in RAW264.7 cell lines decreased SCARB1 and ox-LDL-stimulated CD36 mRNA expression, TGF-β, VEGF-C and α-SMA protein levels and increased the production of IL-6, with downregulation of JAK1/STAT3 signal pathway.

Conclusions

We constructed a diagnostic model of advanced-stage CAD based on the screened 14 DE-IRGs. We verified 4 genes of them to have a strong correlation with CAD, and IL13RA1 might participate in the inflammation, fibrosis, and cholesterol efflux process of atherosclerosis by regulating JAK1/STAT3 pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03614-1.

The influence of phytochemicals on cell heterogeneity in chronic inflammation-associated diseases: the prospects of single cell sequencing

Chronic inflammation-associated diseases include, but is not limited to cardiovascular disease, cancer, obesity, diabetes, etc. Cell heterogeneity is a prerequisite for understanding the physiological and pathological development of cell metabolism, and its response to external stimuli. Recently, dietary habits based on phytochemicals became increasingly recognized to play a pivotal role in chronic inflammation. Phytochemicals can relieve chronic inflammation by regulating inflammatory cell differentiation and immune cell response, but the influence of phytochemicals on cell heterogeneity from in vitro and ex vivo studies cannot simulate the complexity of cell differentiation in vivo due to the differences in cell lines and extracellular environment. Therefore, there is no consensus on the regulation mechanism of phytochemicals on chronic diseases based on cell heterogeneity. The purpose of this review is to summarize cell heterogeneity in common chronic inflammation-associated diseases and trace the effects of phytochemicals on cell differentiation in chronic diseases development. More importantly, by discussing the problems and challenges which hinder the study of cell heterogeneity in recent nutritional assessment experiments, we propose new prospects based on the drawbacks of existing research to optimize the research on the regulation mechanism of phytochemicals on chronic diseases. The need to explore precise measurements of cell heterogeneity is a key pillar in understanding the influence of phytochemicals on certain diseases. In the future, deeper understanding of cell-to-cell variation and the impact of food components and their metabolites on cell function by single-cell genomics and epigenomics with the focus on individual differences will open new avenues for the next generation of health care.

Innate and Adaptive Immune Cells Associates with Arteriovenous Fistula Maturation and Failure

Creation of arteriovenous fistula (AVF) causes local injury resulting in immune response of the body and infiltration of immune cells. Acute inflammation is favorable to control inflammation and proceed AVF towards maturation while chronic inflammation in AVF lead to AVF maturation failure. Chronic inflammation in AVF is due to chronic infiltration of immune cells and secretion of inflammatory cytokines. A balance between pro-inflammatory and anti-inflammatory response is must for AVF maturation and an overwhelmed proinflammatory infiltrate endue chronic inflammation and AVF failure. Since immune cell infiltration plays a critical role in maturation and failure of AVF, it is important to investigate the role of immune cells as well as their density in early and late phase of AVF maturation. The role of inflammation has been discussed in the literature and this review article focuses on the role of pro- and anti-inflammatory immune cells including macrophages, dendritic cells, T-cells, and T-regulatory cells in AVF maturation and maturation failure.

Mmu_circ_0000271 regulated the growth of ox-LDL-stimulated mouse vascular smooth muscle cells via sponging miR-5123

BACKGROUND

Atherosclerosis (AS) is a complex inflammatory disease of the arterial wall. Mmu_circ_0000271 was found to be aberrantly expressed in AS, but its function and mechanism in AS have not been reported.

OBJECTIVE

This study investigated the role of mmu_circ_0000271 in AS.

METHODS

Mmu_circ_0000271 were identified using UCSC website, RNase R treatment, and nuclear‑cytoplasmic extraction. And mouse vascular smooth muscle cells (VSMCs) were used to establish the AS cell model by treating oxidized low-density lipoprotein (ox-LDL, 50 μg/ml). Next, the expression of circ_0000271 in VSMCs was determined by quantitative real-time PCR. The effect of overexpressed or silenced circ_0000271 on ox-LDL-treated VSMCs viability, angiogenesis and invasion were detected by MTT, tube formation and transwell assays. The proteins expressions of proliferative and migratory markers were measured by western blot. After the target relationship predication between circ_0000271 and miR-5123, these experiments were performed again to evaluate the effect of miR-5123 inhibitor on AS model cells.

RESULTS

Mmu_circ_0000271 was stably and highly expressed in ox-LDL-treated VSMCs, and its expression was enriched in the cell cytoplasm. Circ_0000271 overexpression further promoted the ox-LDL-induced viability, angiogenesis and invasion, as well as the proliferation- and migration-related proteins in VSMCs, whereas circ_0000271 knockdown had the opposite effect. Moreover, circ_0000271 was found to target miR-5123 and circ_0000271 overexpression suppressed its expression. And miR-5123 inhibitor was capable of reversing the effect of shcirc_0000271 on AS model cells.

CONCLUSION

Mmu_circ_0000271 regulated ox-LDL-induced VSMC proliferation and migration through bind to miR-5123, and it could serve as a potential biomarker for AS.

The Role of Gut Microbiota in the Immunopathology of Atherosclerosis: focus on immune cells

Gut microbiota (GM) play important roles in multiple organ function, homeostasis and several diseases. More recently, increasing evidences have suggested that the compositional and functional alterations of GM play a crucial role in the accumulation of foam cells and the formation of atherosclerotic plaque in atherosclerosis. In particular, the effects of bacterial components and metabolites on innate and adaptive immune cells have been explored as the underlying mechanisms. Understanding the effects of GM and metabolites on immunoregulation are important for clinical therapy for atherosclerosis. Herein, we summarize the potential role of the GM (such as bacterial components lipopolysaccharide and peptidoglycan) and GM-derived metabolites (such as short-chain fatty acids, trimethylamine N-oxide and bile acids) in the immunopathology of atherosclerosis. Based on that, we further discuss the anti-atherosclerotic effects of GM-directed dietary bioactive factors such as dietary fibers, dietary polyphenols and probiotics. Because of drug-induced adverse events in anti-inflammatory therapies, personalized dietary interventions would be potential therapies for atherosclerosis, and the interactions between GM-derived products and immune cells should be studied further.

Neutrophil Extracellular Traps in Atherosclerosis and Thrombosis

Despite effective therapeutic and preventive strategies, atherosclerosis and its complications still represent a substantial health burden. Leukocytes and inflammatory mechanisms are increasingly recognized as drivers of atherosclerosis. Neutrophil granulocytes within the circulation were recently shown to undergo neutrophil extracellular trap (NET) formation, linking innate immunity with acute complications of atherosclerosis. In this chapter, we summarize mechanisms of NET formation, evidence for their involvement in atherosclerosis and thrombosis, and potential therapeutic regimens specifically targeting NET components.

Immunosuppressive effects of dimethyl fumarate on dendritic cell maturation and migration: a potent protector for coronary heart disease

Dendritic cells (DCs), as a bridge between innate and adaptive immunity, play key roles in atherogenesis, particularly in plaque rupture, the underlying pathophysiologic cause of myocardial infarction. Targeting DC functions, including maturation and migration to atherosclerotic plaques, may be a novel therapeutic approach to atherosclerotic disease. Dimethyl fumarate (DMF), an agent consisting of a combination of fumaric acid esters, in current study were found to be able to suppress DC maturation by reducing the expression of costimulatory molecules and MHC class II and by blocking cytokine secretion. In addition, DMF efficiently inhibited the migration of activated DCs in vitro and in vivo by reducing the expression of chemokine receptor 7 (CCR7). Additionally, DMF efficiently inhibited the expression of the costimulatory molecule CD86, as well as the chemokine receptor CCR7 and the C-X-C motif chemokine receptor 4 (CXCR4), in healthy donor-derived purified DCs that had been stimulated by ST-segment elevation myocardial infarction (STEMI) patient serum. This study points to the potent therapeutic value of DMF for protecting against cardiovascular disease by suppressing DC functions.

Immune system and atherosclerosis: Hostile or friendly relationship

Coronary artery disease has remained a major health challenge despite enormous progress in prevention, diagnosis, and treatment strategies. Formation of atherosclerotic plaque is a chronic process that is developmentally influenced by intrinsic and extrinsic determinants. Inflammation triggers atherosclerosis, and the fundamental element of inflammation is the immune system. The immune system involves in the atherosclerosis process by a variety of immune cells and a cocktail of mediators. It is believed that almost all main components of this system possess a profound contribution to the atherosclerosis. However, they play contradictory roles, either protective or progressive, in different stages of atherosclerosis progression. It is evident that monocytes are the first immune cells appeared in the atherosclerotic lesion. With the plaque growth, other types of the immune cells such as mast cells, and T lymphocytes are gradually involved. Each cell releases several cytokines which cause the recruitment of other immune cells to the lesion site. This is followed by affecting the expression of other cytokines as well as altering certain signaling pathways. All in all, a mix of intertwined interactions determine the final outcome in terms of mild or severe manifestations, either clinical or subclinical. Therefore, it is of utmost importance to precisely understand the kind and degree of contribution which is made by each immune component in order to stop the growing burden of cardiovascular morbidity and mortality. In this review, we present a comprehensive appraisal on the role of immune cells in the atherosclerosis initiation and development.

Dendritic Cell-Targeted Therapies to Treat Neurological Disorders

Dendritic cells (DCs) are the immune system's highly specialized antigen-presenting cells. When DCs are sluggish and mature, self-antigen presentation results in tolerance; however, when pathogen-associated molecular patterns stimulate mature DCs, antigen presentation results in the development of antigen-specific immunity. DCs have been identified in various vital organs of mammals (e.g., the skin, heart, lungs, intestines, and spleen), but the brain has long been thought to be devoid of DCs in the absence of neuroinflammation. However, neuroinflammation is becoming more recognized as a factor in a variety of brain illnesses. DCs are present in the brain parenchyma in trace amounts under healthy circumstances, but their numbers rise during neuroinflammation. New therapeutics are being developed that can reduce dendritic cell immunogenicity by inhibiting pro-inflammatory cytokine production and T cell co-stimulatory pathways. Additionally, innovative ways of regulating dendritic cell growth and differentiation and harnessing their tolerogenic capability are being explored. Herein, we described the function of dendritic cells in neurological disorders and discussed the potential for future therapeutic techniques that target dendritic cells and dendritic cell-related targets in the treatment of neurological disorders.

An insight on the future therapeutic application potential of Stevia rebaudiana Bertoni for atherosclerosis and cardiovascular diseases

Stevia rebaudiana Bertoni is a native plant to Paraguay. The extracts have been used as a famous sweetening agent, and the bioactive components derived from stevia possess a broad spectrum of therapeutical potential for various illnesses. Among its medicinal benefits are anti-hypertensive, anti-tumorigenic, anti-diabetic, and anti-hyperlipidemia. Statins (3-hydro-3-methylglutaryl-coenzyme A reductase inhibitor) are a class of drugs used to treat atherosclerosis. Statins are explicitly targeting the HMG-CoA reductase, an enzyme in the rate-limiting step of cholesterol biosynthesis. Despite being widely used in regulating plasma cholesterol levels, the adverse effects of the drug are a significant concern among clinicians and patients. Hence, steviol glycosides derived from stevia have been proposed as an alternative in replacing statins. Diterpene glycosides from stevia, such as stevioside and rebaudioside A have been evaluated for their efficacy in alleviating cholesterol levels. These glycosides are a potential candidate in treating and preventing atherosclerosis provoked by circulating lipid retention in the sub-endothelial lining of the artery. The present review is an effort to integrate the pathogenesis of atherosclerosis, involvement of lipid droplets biogenesis and its associated proteins in atherogenesis, current approaches to treat atherosclerosis, and pharmacological potential of stevia in treating the disease.

Vascular Inflammation in Cardiovascular Disease: Is Immune System Protective or Bystander?

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. Chronic atherosclerosis induced vascular inflammation and perturbation of lipid metabolism is believed to be a major cause of CVD. Interplay of innate and adaptive Immune system has been interwined with various risk factors associated with the initiation and progression of atherosclerosis in CVD. A large body of evidence indicates a correlation between immunity and atherosclerosis. Retention of plasma lipoproteins in arterial subendothelial wall triggers the T helper type 1 (Th1) cells and monocyte-derived macrophages to form atherosclerotic plaques. In the present review, we will discuss the pathogenesis of CVD in relation to atherosclerosis with a particular focus on pro-atherogenic role of immune cells. Recent findings have also suggested anti-atherogenic roles of different B cell subsets. Therapeutic approaches to target atherosclerosis risk factors have reduced the mortality, but a need exists for the novel therapies to treat arterial vascular inflammation. These insights into the immune pathogenesis of atherosclerosis can lead to new targeted therapeutics to abate cardiovascular mortality and morbidity.

Mechanisms underlying the therapeutic potential of mesenchymal stem cells in atherosclerosis

Atherosclerosis is a chronic inflammatory condition resulting in the formation of fibrofatty plaques within the intimal layer of arterial walls. The identification of resident stem cells in the vascular wall has led to significant investigation into their contributions to health and disease, as well as their therapeutic potential. Of these, mesenchymal stem cells (MSCs) are the most widely studied in human clinical trials, which have demonstrated a modulatory role in vascular physiology and disease. This review highlights the most recent knowledge surrounding the cell biology of MSCs, including their origin, identification markers and differentiation potential. The limitations concerning the implementation of MSC therapy are considered and novel solutions to overcome these are proposed.

Beyond Self-Recycling: Cell-Specific Role of Autophagy in Atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial vessel wall and underlies the development of cardiovascular diseases, such as myocardial infarction and ischemic stroke. As such, atherosclerosis stands as the leading cause of death and disability worldwide and intensive scientific efforts are made to investigate its complex pathophysiology, which involves the deregulation of crucial intracellular pathways and intricate interactions between diverse cell types. A growing body of evidence, including in vitro and in vivo studies involving cell-specific deletion of autophagy-related genes (ATGs), has unveiled the mechanistic relevance of cell-specific (endothelial, smooth-muscle, and myeloid cells) defective autophagy in the processes of atherogenesis. In this review, we underscore the recent insights on autophagy's cell-type-dependent role in atherosclerosis development and progression, featuring the relevance of canonical catabolic functions and emerging noncanonical mechanisms, and highlighting the potential therapeutic implications for prevention and treatment of atherosclerosis and its complications.

Inflammatory Markers Related to Innate and Adaptive Immunity in Atherosclerosis: Implications for Disease Prediction and Prospective Therapeutics

Several lines of evidence have linked a dysregulated inflammatory setting to the pathogenesis of atherosclerosis, which is a form of chronic vascular inflammation. Various inflammatory biomarkers have been associated with inflammation and are recognized as potential tools to monitor the progression of atherosclerosis. A well-studied inflammatory marker in the context of cardiovascular diseases is C-reactive protein (CRP) or, more accurately, highly sensitive-CRP (hs-CRP), which has been established as an inflammatory biomarker for atherosclerotic events. In addition, a growing body of investigations has attempted to disclose the potential of inflammatory cytokines, enzymes, and genetic polymorphisms related to innate and adaptive immunity as biomarkers for predicting the development of atherosclerosis. In this review article, we clarify both traditional and novel inflammatory biomarkers related to components of the innate and adaptive immune system that may mirror the progression or phases of atherosclerotic inflammation/lesions. Furthermore, the contribution of the inflammatory biomarkers in developing potential therapeutics against atherosclerotic treatment will be discussed.

Urolithin A ameliorates experimental autoimmune encephalomyelitis by targeting aryl hydrocarbon receptor

Background

Urolithin A (URA) is an intestinal microbiota metabolic product from ellagitannin-containing foods with multiple biological activities. However, its role in autoimmune diseases is largely unknown. Here, for first time, we demonstrate the therapeutic effect of URA in an experimental autoimmune encephalomyelitis (EAE) animal model.

Methods

Therapeutic effect was evaluated via an active and passive EAE animal model in vivo. The function of URA on bone marrow-derived dendritic cells (BM-DCs), T cells, and microglia were tested in vitro.

Findings

Oral URA (25 mg/kg/d) suppressed disease progression at prevention, induction, and effector phases of preclinical EAE. Histological evaluation showed that significantly fewer inflammatory cells, decreased demyelination, lower numbers of M1-type microglia and activated DCs, as well as reduced infiltrating Th1/Th17 cells were present in the central nervous system (CNS) of the URA-treated group. URA treatment at 25 μM inhibited the activation of BM-DCs in vitro, restrained Th17 cell differentiation in T cell polarization conditions, and in a DC-CD4⁺ T cell co-culture system. Moreover, we confirmed URA inhibited pathogenicity of Th17 cells in adoptive EAE. Mechanism of URA action was directly targeting Aryl Hydrocarbon Receptor (AhR) and modulating the signaling pathways.

Interpretation

Collectively, our study offers new evidence that URA, as a human microbial metabolite, is valuable to use as a prospective therapeutic candidate for autoimmune diseases.

Functional Role of B Cells in Atherosclerosis

Atherosclerosis is a lipid-driven inflammatory disease of blood vessels, and both innate and adaptive immune responses are involved in its development. The impact of B cells on atherosclerosis has been demonstrated in numerous studies and B cells have been found in close proximity to atherosclerotic plaques in humans and mice. B cells exert both atheroprotective and pro-atherogenic functions, which have been associated with their B cell subset attribution. While B1 cells and marginal zone B cells are considered to protect against atherosclerosis, follicular B cells and innate response activator B cells have been shown to promote atherosclerosis. In this review, we shed light on the role of B cells from a different, functional perspective and focus on the three major B cell functions: antibody production, antigen presentation/T cell interaction, and the release of cytokines. All of these functions have the potential to affect atherosclerosis by multiple ways and are dependent on the cellular milieu and the activation status of the B cell. Moreover, we discuss B cell receptor signaling and the mechanism of B cell activation under atherosclerosis-prone conditions. By summarizing current knowledge of B cells in and beyond atherosclerosis, we are pointing out open questions and enabling new perspectives.

Lamin A/C and the Immune System: One Intermediate Filament, Many Faces

Nuclear envelope lamin A/C proteins are a major component of the mammalian nuclear lamina, a dense fibrous protein meshwork located in the nuclear interior. Lamin A/C proteins regulate nuclear mechanics and structure and control cellular signaling, gene transcription, epigenetic regulation, cell cycle progression, cell differentiation, and cell migration. The immune system is composed of the innate and adaptive branches. Innate immunity is mediated by myeloid cells such as neutrophils, macrophages, and dendritic cells. These cells produce a rapid and nonspecific response through phagocytosis, cytokine production, and complement activation, as well as activating adaptive immunity. Specific adaptive immunity is activated by antigen presentation by antigen presenting cells (APCs) and the cytokine microenvironment, and is mainly mediated by the cellular functions of T cells and the production of antibodies by B cells. Unlike most cell types, immune cells regulate their lamin A/C protein expression relatively rapidly to exert their functions, with expression increasing in macrophages, reducing in neutrophils, and increasing transiently in T cells. In this review, we discuss and summarize studies that have addressed the role played by lamin A/C in the functions of innate and adaptive immune cells in the context of human inflammatory and autoimmune diseases, pathogen infections, and cancer.

MALAT1 overexpression attenuates AS by inhibiting ox-LDL-stimulated dendritic cell maturation via miR-155-5p/NFIA axis

MALAT1 is associated with dendritic cells (DCs) maturation in Atherosclerosis (AS). This article aims to demystify the role of MALAT1 in AS. We separated immature DCs (iDCs) from healthy volunteers or ApoE-/- mice. And iDCs were treated with oxidized low density lipoprotein (ox-LDL) to induce DCs maturation. We found that ox-LDL promoted the levels of DCs maturation markers including CD83, CD86, IL-12 and IL-6. MALAT1 and NFIA were down-regulated, whereas miR-155-5p was up-regulated in the ox-LDL-treated iDCs. Furthermore, DCs maturation was notably suppressed by MALAT1 overexpression, NFIA overexpression or miR-155-5p knockdown. Moreover, MALAT1 functioned as a competing endogenous RNA to repress miR-155-5p, which controlled its down-stream target, NFIA. In addition, MALAT1 overexpression inhibited ox-LDL-stimulated DCs maturation by regulating miR-155-5p/NFIA axis. In AS mice, MALAT1 overexpression attenuated ox-LDL-stimulated DCs maturation and reduced atherosclerotic plaque area. In summary, our study demonstrates that MALAT1 overexpression attenuates AS by inhibiting ox-LDL-stimulated DCs maturation via miR-155-5p/NFIA axis. Thus, MALAT1/miR-155-5p/NFIA axis can potentially be used in the treatment of AS.

Potential genes and pathways along with immune cells infiltration in the progression of atherosclerosis identified via microarray gene expression dataset re-analysis

OBJECTIVE

Atherosclerosis is a chronic inflammatory process characterized by the accumulation and formation of lipid-rich plaques within the layers of the arterial wall. Although numerous studies have reported the underlying pathogenesis, no data-based studies have been conducted to analyze the potential genes and immune cells infiltration in the different stages of atherosclerosis via bioinformatics analysis.

METHODS

In this study, we downloaded GSE100927 and GSE28829 from NCBI-GEO database. Gene ontology and pathway enrichment were performed via the DAVID database. The protein interaction network was constructed via STRING. Enriched hub genes were analyzed by the Cytoscape software. The evaluation of the infiltrating immune cells in the dataset samples was performed by the CIBERSORT algorithm.

RESULTS

We identified 114 common upregulated differentially expressed genes and 22 common downregulated differentially expressed genes. (adjust p value < 0.01 and log FC ≥ 1). A cluster of 10 genes including CYBA, SLC11A1, FCER1G, ITGAM, ITGB2, CD53, ITGAX, VAMP8, CLEC5A, and CD300A were found to be significant. Through the deconvolution algorithm CIBERSORT, we analyzed the significant alteration of immune cells infiltration in the progression of atherosclerosis with the threshold of the Wilcoxon test at p value <0.05.

CONCLUSIONS

These results may reveal the underlying correlations between genes and immune cells in atherosclerosis, which enable us to investigate the novel insights for the development of treatments and drugs.

Proteomic analyses reveal that Orf virus induces the activation and maturation of mouse bone marrow-derived dendritic cells

Orf virus (ORFV) is known for its immunostimulatory capacities and has been utilized as an efficient viral vector vaccine in non-permissive host species. Murine bone marrow-derived dendritic cells (BMDCs) are able to react with ORFV. In this study, we aimed to identify pivotal differentially expressed proteins involved in the process of DCs' differentiation in response to ORFV. Our findings showed that ORFV activates the maturation and differentiation of DCs. We further identified and validated seven differentially expressed proteins following ORFV stimulation. With functions in biological processes such as stimulus response, DCs maturation, antigen presentation and Th1 cell activation. Western blot analyses validated the respective changes in protein expression. The huge number of differentially expressed proteins identified in this study will be valuable for elucidating the mechanisms underlying ORFV-induced immunomodulation of murine BMDCs.

Recent discoveries in dendritic cell tolerance-inducing pharmacological molecules

Dendritic cells (DCs) represent one of the most important biological tools for cellular immunotherapy purposes. There are an increasing number of phase I and II studies, where regulatory or tolerogenic DCs (TolDCs) are utilized as negative vaccines, with the aim of inducing tolerogenic outcomes in patients with various autoimmune or chronic-inflammatory diseases, as well as in transplant settings. The induction of tolerogenic properties in DCs can be achieved by altering their activation state toward expression of immunosuppressive elements and/or by achieving resistance to maturation, which leads to insufficient co-stimulatory signal delivery and inability to efficiently present antigens. In the past, one of the most efficient ways to induce DC tolerance has been the application of selected pharmacological agents which actively induce a tolerogenic transcription program or inhibit major pro-inflammatory transcription factors such as Nf-κB. Important examples include immunosuppressants such as different corticosteroids, vitamin D₃, rapamycin and others. The quality of TolDCs induced by different approaches is becoming a vital issue and recent evidence suggests substantial heterogeneity between variously-generated TolDCs as evidenced by their transcriptomic profile and function. The possibility of various "flavors" of TolDCs encourages future research in discovery of Tol-DC inducing agents to enrich various ways of DC manipulation. This would enable a broader range of tools to manipulate DC toward specific characteristics desirable in different disease settings. In recent years, several novel small molecules have been identified with the capacity to promote DC tolerogenic characteristics. In this review, we will present and discuss these novel findings and also highlight novel understandings of tolerogenic mechanisms by which DC tolerogenicity is induced by already established agents.

Getting to the Heart of the Matter: The Role of Regulatory T-Cells (Tregs) in Cardiovascular Disease (CVD) and Atherosclerosis

Cardiovascular diseases (CVD) are the leading cause of mortality worldwide. Atherosclerosis is directly associated with CVD and is characterized by slow progressing inflammation which results in the deposition and accumulation of lipids beneath the endothelial layer in conductance and resistance arteries. Both chronic inflammation and disease progression have been associated with several risk factors, including but not limited to smoking, obesity, diabetes, genetic predisposition, hyperlipidemia, and hypertension. Currently, despite increasing incidence and significant expense on the healthcare system in both western and developing countries, there is no curative therapy for atherosclerosis. Instead patients rely on surgical intervention to avoid or revert vessel occlusion, and pharmacological management of the aforementioned risk factors. However, neither of these approaches completely resolve the underlying inflammatory environment which perpetuates the disease, nor do they result in plaque regression. As such, immunomodulation could provide a novel therapeutic option for atherosclerosis; shifting the balance from proatherogenic to athero-protective. Indeed, regulatory T-cells (Tregs), which constitute 5-10% of all CD4⁺ T lymphocytes in the peripheral blood, have been shown to be athero-protective and could function as new targets in both CVD and atherosclerosis. This review aims to give a comprehensive overview about the roles of Tregs in CVD, focusing on atherosclerosis.

Dioscin attenuates oxLDL uptake and the inflammatory reaction of dendritic cells under high glucose conditions by blocking p38 MAPK

Dioscin has been shown to affect the regulation of metabolic diseases, including diabetes; however, the mechanism of action is still unclear. Under high glucose (HG) conditions, the expression of scavenger receptors and the uptake of oxidized low‑density lipoprotein (oxLDL) are upregulated in dendritic cells (DCs), which are critical steps in atherogenesis and inflammation. In this study, the focus was on the impact of dioscin on the function of DCs. Immature DCs were cultured with: 5.5 mM glucose medium (control group); 30 mM glucose medium (HG group); HG + 10 mM dioscin; HG + 20 mM dioscin; HG + 30 mM dioscin; and HG + 40 mM dioscin. For subsequent experiments, 30 mM dioscin was used as the experimental concentration. Dichlorodihydrofluorescein fluorescence was used to measure the intracellular production of reactive oxygen species (ROS) in DCs. The expression levels of the scavenger receptors, including class A scavenger receptors (SR‑A), CD36 and lectin‑like oxidized low‑density lipoprotein receptor‑1 (LOX‑1) were determined via quantitative PCR. The protein expression of p38 mitogen‑activated protein kinase (MAPK) was determined by western blotting. Furthermore, ELISA was used to detect the levels of interleukin (IL)‑6, IL‑10 and IL‑12. Finally, DCs were incubated with diOlistic (Dil)‑labeled oxLDL, and flow cytometry analysis was used to investigate the Dil‑oxLDL‑incorporated fraction. The incubation of DCs with dioscin inhibited the induction of ROS production, in a dose‑dependent manner, under HG conditions. The upregulation of SR‑A, CD36 and LOX‑1 genes was partially abolished by dioscin, which also partially reversed p38 MAPK protein upregulation. Furthermore, increased secretion of IL‑6 and IL‑12, and decreased secretion of IL‑10 in DCs, induced by HG, was also reversed by dioscin. To conclude, dioscin could attenuate the production of ROS, inflammatory cytokine secretion and oxLDL uptake by DCs in HG conditions by preventing the expression of scavenger receptors and p38 MAPK, thus playing a positive role in preventing atherogenesis.

Immunobiology of Atherosclerosis: A Complex Net of Interactions

Cardiovascular disease is the leading cause of mortality worldwide, and atherosclerosis the principal factor underlying cardiovascular events. Atherosclerosis is a chronic inflammatory disease characterized by endothelial dysfunction, intimal lipid deposition, smooth muscle cell proliferation, cell apoptosis and necrosis, and local and systemic inflammation, involving key contributions to from innate and adaptive immunity. The balance between proatherogenic inflammatory and atheroprotective anti-inflammatory responses is modulated by a complex network of interactions among vascular components and immune cells, including monocytes, macrophages, dendritic cells, and T, B, and foam cells; these interactions modulate the further progression and stability of the atherosclerotic lesion. In this review, we take a global perspective on existing knowledge about the pathogenesis of immune responses in the atherosclerotic microenvironment and the interplay between the major innate and adaptive immune factors in atherosclerosis. Studies such as this are the basis for the development of new therapies against atherosclerosis.

The atherogenic role of immune cells in familial hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipoprotein metabolism that mainly occurs due to mutations in the low-density lipoprotein receptor gene and is characterized by increased levels of low-density lipoprotein cholesterol, leading to accelerated atherogenesis and premature coronary heart disease. Both innate and adaptive immune responses, which mainly include monocytes, macrophages, neutrophils, T lymphocytes, and B lymphocytes, have been shown to play a key role for the initiation and progression of atherogenesis in the general population. In FH patients, these immune cells have been suggested to play specific pro-atherosclerotic activities, from the initial leukocyte recruitment to plaque rupture. In fact, the accumulation of cholesterol crystals and oxLDL in the vessels in FH patients is particularly high, with consequent abnormal mobilization of immune cells and secretion of various pro-inflammatory and chemokines. In addition, cholesterol accumulation in immune cells is exaggerated with chronic exposure to relevant pro-atherosclerotic triggers. The topics considered in this review may provide a more specific focus on the immune system alterations in FH and open new insights toward immune cells as potential therapeutic targets in FH.

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

Supplemental Digital Content is available in the text.

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.

CD39 identifies a microenvironment-specific anti-inflammatory CD8+ T-cell population in atherosclerotic lesions

BACKGROUND AND AIMS

CD8⁺ T-cells have been attributed both atherogenic and atheroprotective properties, but analysis of CD8⁺ T-cells has mostly been restricted to the circulation and secondary lymphoid organs. The atherosclerotic lesion, however, is a complex microenvironment containing a plethora of inflammatory signals, which may affect CD8⁺ T-cell activation. Here, we address how this environment affects the functionality of CD8⁺ T-cells.

METHODS AND RESULTS

We compared the cytokine production of CD8⁺ T-cells derived from spleens and enzymatically digested aortas of apoE^-/- mice with advanced atherosclerosis by flow cytometry. Aortic CD8⁺ T-cells produced decreased amounts of IFN-γ and TNF-α compared to their systemic counterparts. The observed dysfunctional phenotype of the lesion-derived CD8⁺ T-cells was not associated with classical exhaustion markers, but with increased expression of the ectonucleotidase CD39. Indeed, pharmacological inhibition of CD39 in apoE^-/- mice partly restored cytokine production by CD8⁺ T-cells. Using a bone-marrow transplantation approach, we show that TCR signaling is required to induce CD39 expression on CD8⁺ T-cells in atherosclerotic lesions. Importantly, analysis of human endarterectomy samples showed a strong microenvironment specific upregulation of CD39 on CD8⁺ T-cells in the plaques of human patients compared to matched blood samples.

CONCLUSIONS

Our results suggest that the continuous TCR signaling in the atherosclerotic environment in the vessel wall induces an immune regulatory CD8⁺ T-cell phenotype that is associated with decreased cytokine production through increased CD39 expression in both a murine atherosclerotic model and in atherosclerosis patients. This provides a new understanding of immune regulation by CD8⁺ T-cells in atherosclerosis.

Interactions between dyslipidemia and the immune system and their relevance as putative therapeutic targets in atherosclerosis

Cardiovascular disease (CVD) continues to be a leading cause of death worldwide with atherosclerosis being the major underlying pathology. The interplay between lipids and immune cells is believed to be a driving force in the chronic inflammation of the arterial wall during atherogenesis. Atherosclerosis is initiated as lipid particles accumulate and become trapped in vessel walls. The subsequent immune response, involving both adaptive and immune cells, progresses plaque development, which may be exacerbated under dyslipidemic conditions. Broad evidence, especially from animal models, clearly demonstrates the effect of lipids on immune cells from their development in the bone marrow to their phenotypic switching in circulation. Interestingly, recent research has also shown a long-lasting epigenetic signature from lipids on immune cells. Traditionally, cardiovascular therapies have approached atherosclerosis through lipid-lowering medications because, until recently, anti-inflammatory therapies have been largely unsuccessful in clinical trials. However, the recent Canakinumab Antiinflammatory Thrombosis Outcomes Study (CANTOS) provided pivotal support of the inflammatory hypothesis of atherosclerosis in man spurring on anti-inflammatory strategies to treat atherosclerosis. In this review, we describe the interactions between lipids and immune cells along with their specific outcomes as well as discuss their future perspective as potential cardiovascular targets.