Statins induce the accumulation of regulatory T cells in atherosclerotic plaque

Statin prevents cancer development in chronic inflammation by blocking interleukin 33 expression

Chronic inflammation is a major cause of cancer worldwide. Interleukin 33 (IL-33) is a critical initiator of cancer-prone chronic inflammation; however, its induction mechanism by environmental causes of chronic inflammation is unknown. Herein, we demonstrate that Toll-like receptor (TLR)3/4-TBK1-IRF3 pathway activation links environmental insults to IL-33 induction in the skin and pancreas inflammation. An FDA-approved drug library screen identifies pitavastatin to effectively suppress IL-33 expression by blocking TBK1 membrane recruitment/activation through the mevalonate pathway inhibition. Accordingly, pitavastatin prevents chronic pancreatitis and its cancer sequela in an IL-33-dependent manner. The IRF3-IL-33 axis is highly active in chronic pancreatitis and its associated pancreatic cancer in humans. Interestingly, pitavastatin use correlates with a significantly reduced risk of chronic pancreatitis and pancreatic cancer in patients. Our findings demonstrate that blocking the TBK1-IRF3-IL-33 signaling axis suppresses cancer-prone chronic inflammation. Statins present a safe and effective prophylactic strategy to prevent chronic inflammation and its cancer sequela.

Chloroquine Alleviates Atherosclerosis by Modulating Regulatory T Cells Through the ATM/AMPK/mTOR Signaling Pathway in ApoE -/- Mice

BACKGROUND

Clinical observation suggests the atheroprotective effect of chloroquine and its derivatives, while its mechanism remains unclear. This study aimed to observe the protective effect of chloroquine against atherosclerosis and explore the underlying mechanism.

METHODS

Ataxia telangiectasia mutated (ATM) wild-type or haploinsufficient apolipoprotein-E-knockout (ATM+/+ApoE-/- or ATM+/-ApoE-/-) mice were treated with different dosages of chloroquine. Anti-CD25 antibody was used to deplete natural Tregs in ATM+/+ApoE-/- mice. The atherosclerotic burden in different groups of mice was comprehensively evaluated by H&E staining and Masson staining. The effect of chloroquine on the regulatory T cells (Tregs) was assessed in vivo and in vitro by flow cytometry and immunohistochemical staining. The expression of related proteins was detected by real-time polymerase chain reaction and western blotting.

RESULTS

In ATM+/+ApoE-/- mice, chloroquine alleviated atherosclerotic lesions, stabilized the plaque, and increased Treg counts in the atherosclerotic lesions and spleens. However, in ATM haploinsufficient mice (ATM+/-ApoE-/-), chloroquine no longer prevented atherosclerosis or impacted Treg counts. Abolishing Treg cells using an anti-CD25 antibody in vivo abrogated the atheroprotective effect of chloroquine. In vitro, chloroquine promoted the differentiation of Tregs from naïve T cells, which was accompanied by enhanced ATM/AMP-activated protein kinase (AMPK) activity and reduced downstream mammalian target of rapamycin (mTOR) activity.

DISCUSSION

These findings suggest that chloroquine ameliorates atherosclerosis and stabilizes plaque by modulating Tregs differentiation through the regulation of the ATM/AMPK/mTOR pathway.

Complex Interplay Between Metabolism and CD4+ T-Cell Activation, Differentiation, and Function: a Novel Perspective for Atherosclerosis Immunotherapy

Atherosclerosis is a complex pathological process that results from the chronic inflammatory reaction of the blood vessel wall and involves various immune cells and cytokines. An imbalance in the proportion and function of the effector CD4⁺ T-cell (Teff) and regulatory T-cell (Treg) subsets is an important cause of the occurrence and development of atherosclerotic plaques. Teff cells depend on glycolytic metabolism and glutamine catabolic metabolism for energy, while Treg cells mainly rely on fatty acid oxidation (FAO), which is crucial for determining the fate of CD4⁺ T cells during differentiation and maintaining their respective immune functions. Here, we review recent research achievements in the field of immunometabolism related to CD4⁺ T cells, focusing on the cellular metabolic pathways and metabolic reprogramming involved in the activation, proliferation, and differentiation of CD4⁺ T cells. Subsequently, we discuss the important roles of mTOR and AMPK signaling in regulating CD4⁺ T-cell differentiation. Finally, we evaluated the links between CD4⁺ T-cell metabolism and atherosclerosis, highlighting the potential of targeted modulation of CD4⁺ T-cell metabolism in the prevention and treatment of atherosclerosis in the future.

New Concepts on the Pathophysiology of Acute Coronary Syndrome

Acute coronary syndrome (ACS) is the most severe form of ischemic heart disease. Although it is caused by atherosclerotic plaque thrombosis or nonatherosclerotic causes, its pathophysiological mechanism of ACS is not fully understood, and its concept is constantly updated and developed. At present, the main pathophysiological mechanisms include plaque rupture, plaque erosion, calcified nodules (CN) and non-atherosclerotic causes such as coronary vasospasm and myocardial bridging (MB). These mechanisms may overlap and coexist in some ACS patients. Therefore, the pathophysiological mechanism of ACS is complex, and is of great significance for the diagnosis and treatment of ACS. This review will discuss the pathophysiological mechanisms of ACS to provide new thoughts on the pathogenesis, diagnosis and treatment of ACS.

Interleukin-23 receptor signaling impairs the stability and function of colonic regulatory T cells

The cytokine interleukin-23 (IL-23) is involved in the pathogenesis of inflammatory and autoimmune conditions including inflammatory bowel disease (IBD). IL23R is enriched in intestinal Tregs, yet whether IL-23 modulates intestinal Tregs remains unknown. Here, investigating IL-23R signaling in Tregs specifically, we show that colonic Tregs highly express Il23r compared with Tregs from other compartments and their frequency is reduced upon IL-23 administration and impairs Treg suppressive function. Similarly, colonic Treg frequency is increased in mice lacking Il23r specifically in Tregs and exhibits a competitive advantage over IL-23R-sufficient Tregs during inflammation. Finally, IL-23 antagonizes liver X receptor pathway, cellular cholesterol transporter Abca1, and increases Treg apoptosis. Our results show that IL-23R signaling regulates intestinal Tregs by increasing cell turnover, antagonizing suppression, and decreasing cholesterol efflux. These results suggest that IL-23 negatively regulates Tregs in the intestine with potential implications for promoting chronic inflammation in patients with IBD.

The mechanism and treatment of targeted anti-tumour drugs induced cardiotoxicity

As the intensive anti-tumour therapy and combination of multiple anti-tumour drugs, cardiotoxicity events caused by anti-tumour drugs have also increased significantly, and the incidence of cardiotoxicity also increased with survival time. Different types of anti-tumour drugs could cause all kinds of cardiotoxicity which increase the difficulties in treatment and even live threatening. In this review, we concentrated in the targeted anti-tumour drugs such as human epidermal growth factor receptor-2 (HER2) inhibitors, tyrosine kinase inhibitors (TKIs), immune checkpoint inhibitors (ICIs), and proteasome inhibitors (Pls). The molecular mechanism of how these drugs induce cardiotoxicity is introduced which includes several signal pathways. These drugs induced cardiotoxicity involved heart failure, hypertension, atherosis and thrombosis, QT interval prolongation, and myocarditis. Some of the cardiotoxicity could be moderate and reversible but others could have happened severely.The aim of this review is to summarise the targeted anti-tumour drugs induced cardiotoxicity and treatment strategies.

Statin prevents cancer development in chronic inflammation by blocking interleukin 33 expression

Chronic inflammation is a major cause of cancer worldwide. Interleukin 33 (IL-33) is a critical initiator of cancer-prone chronic inflammation; however, its induction mechanism by the environmental causes of chronic inflammation is unknown. Herein, we demonstrate that Toll-like receptor (TLR)3/4-TBK1-IRF3 pathway activation links environmental insults to IL-33 induction in the skin and pancreas. FDA-approved drug library screen identified pitavastatin as an effective IL-33 inhibitor by blocking TBK1 membrane recruitment/activation through the mevalonate pathway inhibition. Accordingly, pitavastatin prevented chronic pancreatitis and its cancer sequela in an IL-33-dependent manner. IRF3-IL-33 axis was highly active in chronic pancreatitis and its associated pancreatic cancer in humans. Interestingly, pitavastatin use correlated with a significantly reduced risk of chronic pancreatitis and pancreatic cancer in patients. Our findings demonstrate that blocking the TBK1-IRF3 signaling pathway suppresses IL-33 expression and cancer-prone chronic inflammation. Statins present a safe and effective therapeutic strategy to prevent chronic inflammation and its cancer sequela.

The effects of statins on the function and differentiation of blood cells

Statins are inhibitors of β-hydroxy β-methylglutaryl-CoA (HMG-CoA) reductase (HMGCR). They are used in patients with cardiovascular risk and/or suffering with cardiovascular disease. In addition to their efficient lipid-lowering effects, statins exhibit independent so called pleiotropic effects potentially affecting several immune response properties including immune cell activation, migration, cytokine generation, immune metabolism, and survival. Statins also regulate innate and acquired immunity. The focus of this review is to highlight the role of statins in modulating the function and differentiation of various blood cells. Given the proposed wider application of these medicines and their potentially important advantages in treatment of inflammatory and autoimmune disorders, more studies are needed with special focus on the molecular targets of statins included in regulating the immune response.

Statin therapy protects against abdominal aortic aneurysms by inducing the accumulation of regulatory T cells in ApoE-/- mice

CD4⁺CD25⁺ regulatory T cells (Tregs) have been shown to protect against abdominal aortic aneurysm (AAA) progression. Statins have immunomodulatory properties, and their effect on AAA partly depends on immune-related mechanisms. In this study, we aimed to explore whether there is an association between statins and Tregs in AAA progression. Sixty ApoE^-/- mice were randomly divided into four groups (n = 15 per group): A, saline group; B, control group; C, simvastatin group (intragastric administration of simvastatin); and D, PC61 group (simvastatin combined with an intraperitoneal injection of 100 μg CD25-depleting antibody PC61). After 2 weeks of simvastatin treatment, the mice received a continuous subcutaneous infusion of angiotensin II (Ang II; B, C, and D groups) or saline (A group) for 28 days. Simvastatin therapy for 6 weeks significantly decreased the incidence and severity of AAA and inhibited the apoptosis of smooth muscle cells and generation of reactive oxygen species, which was partly abolished after the injection of PC61 antibody. Importantly, simvastatin increased the number of Tregs and the levels of Treg-associated cytokines (TGF-β and IL-10) and decreased the level of IL-17 both in aortic tissues and serum. Interestingly, simvastatin attenuated Ang II-induced gut microbial dysbiosis, which might be associated with the accumulation of Tregs. In conclusion, simvastatin therapy prevented the development of AAA induced by Ang II in ApoE^-/- mice, which might be partly due to the induction of Treg accumulation. In addition, simvastatin regulated gut microbial dysbiosis, which might also be associated with Treg generation.

The cholesterol pathway: impact on immunity and cancer

Cholesterol is a multifaceted metabolite that is known to modulate processes in cancer, atherosclerosis, and autoimmunity. A common denominator between these diseases appears to be the immune system, in which many cholesterol-associated metabolites impact both adaptive and innate immunity. Many cancers display altered cholesterol metabolism, and recent studies demonstrate that manipulating systemic cholesterol metabolism may be useful in improving immunotherapy responses. However, cholesterol can have both proinflammatory and anti-inflammatory roles in mammals, acting via multiple immune cell types, and depending on context. Gaining mechanistic insights into various cholesterol-related metabolites can improve our understanding of their functions and extensive effects on the immune system, and ideally will inform the design of future therapeutic strategies against cancer and/or other pathologies.

Effects of Low-Dose Atorvastatin on the Peripheral Blood Mononuclear Cell Secretion of Angiogenic Factors in Type 2 Diabetes

The aim of this study was to investigate the influence of statins on the secretion of angiogenesis mediators by the peripheral blood mononuclear cells (PBMCs) derived from patients suffering from type 2 diabetes. The study group comprised 30 participants and included: 10 statin-treated patients with diabetes, 10 statin-free diabetic subjects, and 10 statin-free non-diabetic individuals. PBMCs isolated from the blood were cultured in vitro in standard conditions and in an environment mimicking hyperglycemia. Culture supernatants were evaluated for VEGF, MCP-1, Il-10, and Il-12 by flow cytometry using commercial BD^TM. Cytometric Bead Array tests. The secretion of VEGF, MCP-1 and Il-12 by PBMCs, cultured both in standard and hyperglycemic conditions, was significantly lower in the statin-treated patients with type 2 diabetes in comparison with the statin-free diabetic patients. Conversely, the secretion of Il-10 was higher in the statin-treated than in the statin-free diabetic patients. VEGF, MCP-1 and Il-12 levels in PBMCs supernatants from the glucose-containing medium were higher than those from the standard medium in each of the diabetic groups. The results of the study suggest that statins in low doses exhibit an antiangiogenic activity, reducing the secretion of potent proangiogenic factors, such as VEGF and MCP-1, and increasing the secretion of antiangiogenic Il-10 by PBMCs, also under hyperglycemic conditions characteristic for type 2 diabetes.

The role of lipid metabolism in shaping the expansion and the function of regulatory T cells

Metabolic inflammation, defined as a chronic low-grade inflammation, is implicated in numerous metabolic diseases. In recent years, the role of regulatory T cells (Tregs) as key controllers of metabolic inflammation has emerged, but our comprehension on how different metabolic pathways influence Treg functions needs a deeper understanding. Here we focus on how circulating and intracellular lipid metabolism, in particular cholesterol metabolism, regulates Treg homeostasis, expansion, and functions. Cholesterol is carried through the bloodstream by circulating lipoproteins (chylomicrons, very low-density lipoproteins, low-density lipoproteins). Tregs are equipped with a wide array of metabolic sensors able to perceive and respond to changes in the lipid environment through the activation of different intracellular pathways thus conferring to these cells a crucial metabolic and functional plasticity. Nevertheless, altered cholesterol transport, as observed in genetic dyslipidemias and atherosclerosis, impairs Treg proliferation and function through defective cellular metabolism. The intracellular pathway devoted to the cholesterol synthesis is the mevalonate pathway and several studies have shown that this pathway is essential for Treg stability and suppressive activity. High cholesterol concentrations in the extracellular environment may induce massive accumulation of cholesterol inside the cell thus impairing nutrients sensors and inhibiting the mevalonate pathway. This review summarizes the current knowledge regarding the role of circulating and cellular cholesterol metabolism in the regulation of Treg metabolism and functions. In particular, we will discuss how different pathological conditions affecting cholesterol transport may affect cellular metabolism in Tregs.

Atorvastatin restores imbalance of cluster of differentiation 4 (CD4)+ T cells in immune thrombocytopenia in vivo and in vitro

Immune thrombocytopenia (ITP) is an autoimmune haemorrhagic disease, in which the overactivation of T cells is crucial in the pathogenesis. Atorvastatin (AT), a lipid-lowering medicine, has shown promising immunomodulatory effects in certain inflammatory conditions. However, the immunoregulatory role of AT in ITP remains elusive. To investigate the effect of AT in the treatment of ITP, cluster of differentiation 4 (CD4)⁺ T cells were isolated from patients with ITP and cultured with different dosages of AT. We found that AT significantly inhibited cell proliferation, led to cell cycle arrest, induced apoptosis, and repressed the activation of CD4⁺ T cells in vitro. ITP murine models were then established, and results showed that AT treatment led to faster recovery of the platelet count to normal and exhibited comparable immunomodulatory function. Furthermore, we found the phosphorylation of mammalian target of rapamycin (mTOR), protein kinase B (AKT) and extracellular signal-regulated kinase (ERK), as well as activation of rat sarcoma virus (RAS) were all reduced dramatically after AT treatment in vitro. In conclusion, our present study demonstrated that AT could reinstate the functions of CD4⁺ T cells by inhibiting the excessive activation, proliferation, and survival of CD4⁺ T cells in ITP via the RAS/mitogen-activated protein kinase kinase (MEK)/ERK and the mTOR/phosphatidylinositol-3 kinase (PI3K)/AKT pathway. Therefore, we propose that AT could be used as a potential therapeutic option for ITP by restoring the over-activated cellular immunity.

Regulatory T Cells: A New Target of Chinese Medicine in Treatment of Atherosclerosis

Inflammation and immune disorders are integral to the occurrence and progression of atherosclerosis (AS). With the role of regulatory T cells (Tregs) in immune regulation attracting attention, it has been widely accepted that Treg decrease and dysfunction are involved in AS pathogenesis. Chinese medicine (CM) has the advantages of being dual-directional, multi-targeted, and having minimal side effects in immune regulation. The anti-atherosclerosis effects of CM via Treg modulation have been revealed in clinical and animal studies. Therefore, this article reviews existing research on Tregs, the relationship between Tregs and AS, and the progress of CM for treating and prevention of atherosclerotic cardio-cerebrovascular diseases by regulating Tregs. Although the underlying mechanisms remain to be elucidated, CM treatment targeting Treg cells might provide a promising and novel future approach for prevention and treatment of AS.

Atherosclerosis: immunopathogenesis and strategies for immunotherapy

Atherosclerosis, a chronic inflammatory condition in which atheroma accumulates within the intima of the arterial wall, is a life-threatening manifestation of cardiovascular disease, due to atheroma rupture, chronic luminal narrowing and thrombosis. Current knowledge of the role of a protective immune response in atherosclerotic lesions has provided promising opportunities to develop new immunotherapeutic strategies. In particular, Tregs exert an atheroprotective role by releasing anti-inflammatory cytokines (IL-10/TGF-β) and suppressing autoreactive T lymphocytes. In vivo animal experiments have shown that this can be achieved by developing vaccines that stimulate immunological tolerance to atheroma antigens. Here, we present an overview of the current knowledge of the proatherogenic immune response, and we discuss the strategies currently used as immunoregulatory therapy.

Immunity in Atherosclerosis: Focusing on T and B Cells

Atherosclerosis is the major cause of the development of cardiovascular disease, which, in turn, is one of the leading causes of mortality worldwide. From the point of view of pathogenesis, atherosclerosis is an extremely complex disease. A huge variety of processes, such as violation of mitophagy, oxidative stress, damage to the endothelium, and others, are involved in atherogenesis; however, the main components of atherogenesis are considered to be inflammation and alterations of lipid metabolism. In this review, we want to focus on inflammation, and more specifically on the cellular elements of adaptive immunity, T and B cells. It is known that various T cells are widely represented directly in atherosclerotic plaques, while B cells can be found, for example, in the adventitia layer. Of course, such widespread and well-studied cells have attracted attention as potential therapeutic targets for the treatment of atherosclerosis. Various approaches have been developed and tested for their efficacy.

Simvastatin Reduces Protection and Intestinal T Cell Responses Induced by a Norovirus P Particle Vaccine in Gnotobiotic Pigs

Noroviruses (NoVs) are a leading cause of acute gastroenteritis worldwide. P particles are a potential vaccine candidate against NoV. Simvastatin is a cholesterol-reducing drug that is known to increase NoV infectivity. In this study, we examined simvastatin’s effects on P particle-induced protective efficacy and T-cell immunogenicity using the gnotobiotic pig model of human NoV infection and diarrhea. Pigs were intranasally inoculated with three doses (100 µg/dose) of GII.4/VA387-derived P particles together with monophosphoryl lipid A and chitosan adjuvants. Simvastatin-fed pigs received 8 mg/day orally for 11 days prior to challenge. A subset of pigs was orally challenged with 10 ID₅₀ of a NoV GII.4/2006b variant at post-inoculation day (PID) 28 and monitored for 7 days post-challenge. Intestinal and systemic T cell responses were determined pre- and postchallenge. Simvastatin abolished the P particle’s protection and significantly increased diarrhea severity after NoV infection. Simvastatin decreased proliferation of virus-specific and non-specific CD8 T cells in duodenum and virus-specific CD4 and CD8 T cells in spleen and significantly reduced numbers of intestinal mononuclear cells in vaccinated pigs. Furthermore, simvastatin significantly decreased numbers of duodenal CD4+IFN-γ+, CD8+IFN-γ+ and regulatory T cells and total duodenal activated CD4+ and CD8+ T cells in vaccinated pigs pre-challenge at PID 28. Following challenge, simvastatin prevented the IFN-γ+ T cell response in spleen of vaccinated pigs. These results indicate that simvastatin abolished P particle vaccine-induced partial protection through, at least in part, impairing T cell immunity. The findings have specific implications for the development of preventive and therapeutic strategies against NoV gastroenteritis, especially for the elderly population who takes statin-type drugs.

Antiretroviral therapy-treated HIV-infected adults with coronary artery disease are characterized by a distinctive regulatory T-cell signature

BACKGROUND

Despite the success of antiretroviral therapy (ART) to control viral replication, people living with HIV (PWH) have high levels of chronic systemic inflammation and immune dysregulation which drives accelerated co-morbidities including coronary artery disease (CAD). Regulatory T cells (Tregs) and ectonucleotidases CD39/CD73 are known to be athero-protective via their immunosuppressive and anti-inflammatory functions.

DESIGN

We assessed the dynamics of Treg subsets in ART-treated PWH with or without CAD vs. HIV-uninfected individuals.

METHODS

Blood specimens were obtained from 142 participants including ART-treated HIV-infected adults with (n = 43) or without CAD (n = 41), as well as HIV-uninfected controls with (n = 31) or without CAD (n = 27). CAD was determined by the presence of atherosclerotic features on computed tomography angiography of the coronary arteries performed on all study participants. Treg subsets frequencies were assessed by flow cytometry.

RESULTS

Regardless of statin treatment or ART regimen, HIV+CAD+ individuals had the highest total Treg frequencies and increased thymic generation and output of Tregs (Helios/CD31 expression), while athero-protective CD39+/CD73+ Tregs were significantly depleted in this group. Tregs from PWH had higher expression of CCR6/CXCR3 than uninfected individuals regardless of CAD, while in HIV+CAD+ individuals Tregs expressed the highest levels of CCR4, which limits their maintenance. The lowest levels of CD4+ and CD8+ T-cell immune activation has been observed in HIV+CAD+ within study groups.

CONCLUSION

ART-treated PWH with diagnosed CAD are characterized by profound alterations in populations of anti-inflammatory and athero-protective Treg subsets. These changes may contribute to atherosclerotic plaque formation and progression during chronic HIV infection in the ART era.

Heart Failure With Targeted Cancer Therapies: Mechanisms and Cardioprotection

Oncology has seen growing use of newly developed targeted therapies. Although this has resulted in dramatic improvements in progression-free and overall survival, challenges in the management of toxicities related to longer-term treatment of these therapies have also become evident. Although a targeted approach often exploits the differences between cancer cells and noncancer cells, overlap in signaling pathways necessary for the maintenance of function and survival in multiple cell types has resulted in systemic toxicities. In particular, cardiovascular toxicities are of important concern. In this review, we highlight several targeted therapies commonly used across a variety of cancer types, including HER2 (human epidermal growth factor receptor 2)+ targeted therapies, tyrosine kinase inhibitors, immune checkpoint inhibitors, proteasome inhibitors, androgen deprivation therapies, and MEK (mitogen-activated protein kinase kinase)/BRAF (v-raf murine sarcoma viral oncogene homolog B) inhibitors. We present the oncological indications, heart failure incidence, hypothesized mechanisms of cardiotoxicity, and potential mechanistic rationale for specific cardioprotective strategies.

Proinflammatory protein signatures in cryptogenic and large artery atherosclerosis stroke

Objectives

The cause of ischemic stroke remains unknown, cryptogenic, in 25% of young and middle‐aged patients. We hypothesized that if atherosclerosis is prominent in cryptogenic stroke, it would have a similar proinflammatory protein signature as large artery atherosclerosis (LAA) stroke.

Materials & Methods

Blood was collected in the acute phase and after 3 months from cryptogenic (n = 162) and LAA (n = 73) stroke patients aged 18–69 years and once from age‐matched controls (n = 235). Cryptogenic stroke was divided into Framingham Risk Score (FRS) quartiles to compare low and high risk of atherosclerosis. Plasma concentrations of 25 proteins were analyzed using a Luminex multiplex assay. The discriminating properties were assessed with discriminant analysis and C‐statistics.

Results

We identified proteins that separated cryptogenic and LAA stroke from controls (area under the curves, AUCs ≥ 0.85). For both subtypes, RANTES, IL‐4, and IFN‐γ contributed the most at both time points. These associations were independent of risk factors of atherosclerosis. We also identified proteins that separated cryptogenic strokes in the lowest quartile of FRS from those in the highest, and from LAA stroke (AUCs ≥ 0.76), and here eotaxin and MCP‐1 contributed the most.

Conclusions

The protein signature separating cases from controls was different from the signature separating cryptogenic stroke with low risk of atherosclerosis from those with high risk and from LAA stroke. This suggests that increased RANTES, IL‐4, and IFN‐γ in stroke may not be primarily related to atherosclerosis, whereas increased eotaxin and MCP‐1 in cryptogenic stroke may be markers of occult atherosclerosis as the underlying cause.

Pitavastatin ameliorates autoimmune neuroinflammation by regulating the Treg/Th17 cell balance through inhibition of mevalonate metabolism

While Treg cells are responsible for self-tolerance and immune homeostasis, pathogenic autoreactive Th17 cells produce pro-inflammatory cytokines that lead to tissue damage associated with autoimmunity, as observed in multiple sclerosis. Therefore, the immunological balance between Th17 and Treg cells may represent a promising option for immune therapy. Statin drugs are used to treat dyslipidemia; however, besides their effects on preventing cardiovascular diseases, statins also have anti-inflammatory effects. Here, we investigated the role of pitavastatin on experimental autoimmune encephalomyelitis (EAE) and the differentiation of Treg and Th17 cells. EAE was induced by immunizing C57BL/6 mice with MOG35-55. EAE severity was determined by analyzing the clinical score and inflammatory parameters in the spinal cord. Naive CD4 T cells were cultured under Treg and Th17-skewing conditions in vitro in the presence of pitavastatin. We found that pitavastatin decreased EAE development, which was accompanied by a reduction of all parameters investigated. Pitavastatin also reduced the expression of IBA1 and pSTAT3 (Y705 and S727) in the spinal cords of EAE mice. Interestingly, the reduction of Th17 cell frequency in the draining lymph nodes of EAE mice treated with pitavastatin was followed by an increase of Treg cells. Indeed, pitavastatin directly affects T cell differentiation in vitro by decreasing Th17 and increasing Treg cell differentiation. Mechanistically, pitavastatin effects are dependent on mevalonate synthesis. Thus, our data show the potential anti-inflammatory effect of pitavastatin on the pathogenesis of the experimental neuroinflammation by modulating the Th17/Treg axis.

Adaptive Immune Responses in 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⁺CD28^null 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.

Delicate Role of PD-L1/PD-1 Axis in Blood Vessel Inflammatory Diseases: Current Insight and Future Significance

Immune checkpoint molecules are the antigen-independent generator of secondary signals that aid in maintaining the homeostasis of the immune system. The programmed death ligand-1 (PD-L1)/PD-1 axis is one among the most extensively studied immune-inhibitory checkpoint molecules, which delivers a negative signal for T cell activation by binding to the PD-1 receptor. The general attributes of PD-L1's immune-suppressive qualities and novel mechanisms on the barrier functions of vascular endothelium to regulate blood vessel-related inflammatory diseases are concisely reviewed. Though targeting the PD-1/PD-L1 axis has received immense recognition-the Nobel Prize in clinical oncology was awarded in the year 2018 for this discovery-the use of therapeutic modulating strategies for the PD-L1/PD-1 pathway in chronic inflammatory blood vessel diseases is still limited to experimental models. However, studies using clinical specimens that support the role of PD-1 and PD-L1 in patients with underlying atherosclerosis are also detailed. Of note, delicate balances in the expression levels of PD-L1 that are needed to preserve T cell immunity and to curtail acute as well as chronic infections in underlying blood vessel diseases are discussed. A significant link exists between altered lipid and glucose metabolism in different cells and the expression of PD-1/PD-L1 molecules, and its possible implications on vascular inflammation are justified. This review summarizes the most recent insights concerning the role of the PD-L1/PD-1 axis in vascular inflammation and, in addition, provides an overview exploring the novel therapeutic approaches and challenges of manipulating these immune checkpoint proteins, PD-1 and PD-L1, for suppressing blood vessel inflammation.

T-Cell Hyperactivation and Paralysis in Severe COVID-19 Infection Revealed by Single-Cell Analysis

Severe COVID-19 patients show various immunological abnormalities including T-cell reduction and cytokine release syndrome, which can be fatal and is a major concern of the pandemic. However, it is poorly understood how T-cell dysregulation can contribute to the pathogenesis of severe COVID-19. Here we show single cell-level mechanisms for T-cell dysregulation in severe COVID-19, demonstrating new pathogenetic mechanisms of T-cell activation and differentiation underlying severe COVID-19. By in silico sorting CD4+ T-cells from a single cell RNA-seq dataset, we found that CD4+ T-cells were highly activated and showed unique differentiation pathways in the lung of severe COVID-19 patients. Notably, those T-cells in severe COVID-19 patients highly expressed immunoregulatory receptors and CD25, whilst repressing the expression of FOXP3. Furthermore, we show that CD25⁺ hyperactivated T-cells differentiate into multiple helper T-cell lineages, showing multifaceted effector T-cells with Th1 and Th2 characteristics. Lastly, we show that CD25-expressing hyperactivated T-cells produce the protease Furin, which facilitates the viral entry of SARS-CoV-2. Collectively, CD4⁺ T-cells from severe COVID-19 patients are hyperactivated and FOXP3-mediated negative feedback mechanisms are impaired in the lung, which may promote immunopathology. Therefore, our study proposes a new model of T-cell hyperactivation and paralysis that drives immunopathology in severe COVID-19.

Medical Treatment Can Unintentionally Alter the Regulatory T-Cell Compartment in Patients with Widespread Pathophysiologic Conditions

Regulatory T cells (Tregs) are non-redundant mediators of immune tolerance that are critical to prevent autoimmune disease and promote an anti-inflammatory tissue environment. Many individuals experience chronic diseases and physiologic changes associated with aging requiring long-term medication. Unfortunately, adverse effects accompany every pharmacologic intervention and may affect overall outcomes. We focus on medications typically prescribed during the treatment of prevalent chronic diseases and disorders, including cardiovascular disease, autoimmune disease, and menopausal symptoms, that affect >200 million individuals in the United States. Increasing studies continue to report that treatment of patients with estrogen, metformin, statins, vitamin D, and tumor necrosis factor blockers are unintentionally modulating the Treg compartment. Effects of these medications likely comprise direct and/or indirect interaction with Tregs via other immune and parenchymal populations. Differing and sometimes opposing effects on the Treg compartment have been observed using the same medication. The length of treatment, dosing regimen and stage of disease, patient age, ethnicity, and sex may account for such findings and determine the specific signaling pathways affected by the medication. Enhancing the Treg compartment can skew the patient's immune system toward an anti-inflammatory phenotype and therefore could provide unanticipated benefit. Currently, multiple medicines prescribed to large numbers of patients influence the Treg compartment; however, how such effects affect their disease outcome and long-term health remains unclear.

Impact of Cholesterol Metabolism in Immune Cell Function and Atherosclerosis

Cholesterol, the most important sterol in mammals, helps maintain plasma membrane fluidity and is a precursor of bile acids, oxysterols, and steroid hormones. Cholesterol in the body is obtained from the diet or can be de novo synthetized. Cholesterol homeostasis is mainly regulated by the liver, where cholesterol is packed in lipoproteins for transport through a tightly regulated process. Changes in circulating lipoprotein cholesterol levels lead to atherosclerosis development, which is initiated by an accumulation of modified lipoproteins in the subendothelial space; this induces significant changes in immune cell differentiation and function. Beyond lesions, cholesterol levels also play important roles in immune cells such as monocyte priming, neutrophil activation, hematopoietic stem cell mobilization, and enhanced T cell production. In addition, changes in cholesterol intracellular metabolic enzymes or transporters in immune cells affect their signaling and phenotype differentiation, which can impact on atherosclerosis development. In this review, we describe the main regulatory pathways and mechanisms of cholesterol metabolism and how these affect immune cell generation, proliferation, activation, and signaling in the context of atherosclerosis.

Statins reduce vascular inflammation in atherogenesis: A review of underlying molecular mechanisms

Chronic inflammation enhances the detrimental role of dyslipidaemia during atherogenesis. Statins are among the most effective anti-atherosclerotic medications, being able to impact on both cardiovascular morbidity and mortality. Although these molecules have been first described as lipid-lowering medications, several lines of evidence suggest additional benefits through their "pleiotropic" anti-atherosclerotic activities. Specifically, statins can modulate vascular atherosclerotic inflammation by directly improving functions of endothelial cells, vascular smooth muscle cells, platelets, and immune cells. Here, we discuss basic and clinical evidence to provide an update on the molecular mechanisms underlying the protective anti-inflammatory role of statins in atherogenesis.

Intensive statin treatment ameliorate the Th17/Treg functional imbalance in patients with non-ST elevation acute coronary syndrome underwent percutaneous coronary intervention

Background

Inflammation plays important roles in the pathogenesis of acute coronary syndrome (ACS). Statins exert positive effects on the plaque stabilization through anti‐inflammation, however, the detailed mechanism is still under investigation.

Hypothesis

Studies suggest that the Th17/Treg functional imbalance takes key part in the plaque destabilization and the onset of ACS. We hypothesized that intensive statin therapy could ameliorate the Th17/Treg imbalance in patients with ACS.

Methods

Sixty‐six patients with non‐ST elevation acute coronary syndrome (NSTE‐ACS) were randomized to conventional group and intensive group. Peripheral blood samples were collected on admission and after atorvastatin treatment. The frequencies of circulating Th17 cells and Treg cells, the levels of cytokines associated with Th17 cells (IL‐17, IL‐6 and IL‐23) and associated with Treg cells (IL‐10 and TGF‐β1) were measured through flow cytometry and ELISA assay respectively.

Results

One week after therapy, the frequencies of circulating Th17 cells of both the groups decreased and the frequencies of circulating Treg cells increased significantly, compared with the basal levels. Furthermore, the decreased frequencies of circulating Th17 cells and the increased frequencies of circulating Treg cells in the intensive group were significantly higher than those in the conventional group. In consistence, the decreased accumulation of IL‐17, IL‐6 and IL‐23 (cytokines relevant to Th17 cells) and the increased accumulation of IL‐10 and TGF‐β1 in peripheral blood were displayed in both groups. The changes are more significant in the intensive group.

Conclusion

Intensive statins therapy could ameliorate the Th17 and Treg functional imbalance in patients with ACS.

Regulatory T cells: Possible mediators for the anti-inflammatory action of statins

Statins beside their main effect on reducing the progression of cardiovascular disease through pharmacological inhibition of the endogenous cholesterol synthesis, have additional pleiotropic effects including antiinflammatory effects mediated through the induction of suppressor regulatory T cells (Tregs). Statin-induced expansion of Tregs reduces chronic inflammation and may have beneficial effects in autoimmune diseases. However, statins could represent a double-edged sword in immunomodulation. Drugs that act by increasing the concentration of Tregs could enhance the risk of cancers, particularly in the elderly and may have adverse effects in neurodegenerative disorders and infectious diseases. In the present paper, we review the experimental studies that evaluate the effects of statins on Treg cells in autoimmune and inflammatory diseases and we discuss potential therapeutic applications of statins in this setting.

[Preprocedural high - sensitivity C-reactive protein (hsCRP) decrease during intensive atorvastatin therapy: the presumable impact on atherosclerosis progression after coronary stenting]

Proinflammatory status is the risk factor for coronary atherosclerosis progression after coronary stenting (CS). Intensive statin treatment is associated with hsCRP concentration decline.

AIM

to evaluate prognostic significance of preprocedural hsCRP level reduction with intensive statin regimen for coronary atherosclerosis progression during one year after CS.

MATERIALS AND METHODS

We enrolled 102 patients with stable angina who were on list for scheduled CS. Group I (n=37) patients received atorvastatin 80 mg for 7 days before and 3 months after CS with further dose adjustment according to LDL; group II (n=65) patients received atorvastatin 20-40 mg/day for LDL goal achievement. HsCRP level was assessed at baseline, before CS and after 1, 3, 6 and 12 months. Coronary atherosclerosis progression was defined as new ≥50% stenosis or ≥30% increase of ≥20% pre - existing stenosis according to coronary angiography (CA) 1 year after CS.

RESULTS

Baseline concentration of hsCRP was comparable: 0.21 (0.13; 0.38) vs. 0.20 (0.1; 0.44) mg/dl in groups I and II, respectively (p>0.05). In group I significant hsCRP level decrease to 0.14 (0.07; 0.32) mg/dl (p.

The Effect of Statins on the Functionality of CD4+CD25+FOXP3+ Regulatory T-cells in Acute Coronary Syndrome: A Systematic Review and Meta-analysis of Randomised Controlled Trials in Asian Populations

Acute coronary syndrome (ACS) is characterised by increased effector cells and decreased regulatory T-cells (Tregs). Statins have been shown to be clinically beneficial in ACS patients. This effect could be mediated via the induction of Tregs in ACS patients. The aim of this systemic review and meta-analysis was to evaluate whether statin therapy enhances the frequency of Tregs determined by CD4+CD25+FOXP3+ in this subset of patients. A comprehensive search of PubMed and Embase was performed. Studies were restricted to randomised controlled trials that quantified CD4+CD25+FOXP3+ cell frequency by flow cytometric analysis before and after statin treatment in adults diagnosed with ACS. A minimum of at least two of the conventional markers to identify Tregs was compulsory. Four randomised controlled trials studies (439 participants) were included, all with low-to-moderate risk of bias. Pooled data showed a significant increase in Treg frequency after statin therapy in ACS patients. A further meta-regression and subgroup analysis also showed a negative dose-related effect, and a statin type-related effect (rosuvastatin versus atorvastatin), respectively. The results confirmed that statins positively alter the frequency of Tregs, which may indicate a potential mechanism of their therapeutic effect. However, there was a risk of information bias due to the markers used to identify Tregs, which was not fully explored, therefore, further randomised controlled trials should utilise markers of Tregs, such as the FOXP3 locus (Treg-specific demethylated region), for identification.

Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation

Atherosclerosis is a chronic vascular inflammatory disease associated to oxidative stress and endothelial dysfunction. Oxidation of low-density lipoprotein (LDL) cholesterol is one of the key factors for the development of atherosclerosis. Nonoxidized LDL have a low affinity for macrophages, so they are not themselves a risk factor. However, lowering LDL levels is a common clinical practice to reduce oxidation and the risk of major events in patients with cardiovascular diseases (CVD). Atherosclerosis starts with dysfunctional changes in the endothelium induced by disturbed shear stress which can lead to endothelial and platelet activation, adhesion of monocytes on the activated endothelium, and differentiation into proinflammatory macrophages, which increase the uptake of oxidized LDL (oxLDL) and turn into foam cells, exacerbating the inflammatory signalling. The atherosclerotic process is accelerated by a myriad of factors, such as the release of inflammatory chemokines and cytokines, the generation of reactive oxygen species (ROS), growth factors, and the proliferation of vascular smooth muscle cells. Inflammation and immunity are key factors for the development and complications of atherosclerosis, and therefore, the whole atherosclerotic process is a target for diagnosis and treatment. In this review, we focus on early stages of the disease and we address both biomarkers and therapeutic approaches currently available and under research.

Elevated circulating effector memory T cells but similar levels of regulatory T cells in patients with type 2 diabetes mellitus and cardiovascular disease

Type 2 diabetes mellitus is associated with an elevated risk of cardiovascular disease, but the mechanism through which diabetes contributes to cardiovascular disease development remains incompletely understood. In this study, we compared the association of circulating regulatory T cells, naïve T cells, effector memory T cells or central memory T cells with cardiovascular disease in patients with and without type 2 diabetes mellitus. Percentage of circulating T cell subsets was analysed by flow cytometry in type 2 diabetes mellitus subjects with and without prevalent cardiovascular disease as well as in non-diabetic subjects with and without prevalent cardiovascular disease from the Malmö SUMMIT cohort. Subjects with type 2 diabetes mellitus had elevated percentages of effector memory T cells (CD4⁺CD45RO⁺CD62L^-; 21.8% ± 11.2% vs 17.0% ± 9.2% in non-type 2 diabetes mellitus, p < 0.01) and central memory T cells (CD4⁺CD45RO⁺CD62L⁺; 38.0% ± 10.7% vs 36.0% ± 9.5% in non-type 2 diabetes mellitus, p < 0.01). In contrast, the frequency of naïve T cells was reduced (CD4⁺CD45RO^-CD62L⁺, 35.0% ± 16.5% vs 42.9% ± 14.4% in non-type 2 diabetes mellitus, p < 0.001). The proportion of effector memory T cells was increased in type 2 diabetes mellitus subjects with cardiovascular disease as compared to those without (26.4% ± 11.5% vs 18.4% ± 10.2%, p < 0.05), while no difference in regulatory T cells was observed between these two patient groups. This study identifies effector memory T cells as a potential cellular biomarker for cardiovascular disease among subjects with type 2 diabetes mellitus, suggesting a state of exacerbated immune activation in type 2 diabetes mellitus patients with cardiovascular disease.

Antioxidative Property and Molecular Mechanisms Underlying Geniposide-Mediated Therapeutic Effects in Diabetes Mellitus and Cardiovascular Disease

Geniposide, an iridoid glucoside, is a major component in the fruit of Gardenia jasminoides Ellis (Gardenia fruits). Geniposide has been experimentally proved to possess multiple pharmacological actions involving antioxidative stress, anti-inflammatory, antiapoptosis, antiangiogenesis, antiendoplasmic reticulum stress (ERS), etc. In vitro and in vivo studies have further identified the value of geniposide in a spectrum of preclinical models of diabetes mellitus (DM) and cardiovascular disorders. The antioxidative property of geniposide should be attributed to the result of either the inhibition of numerous pathological processes or the activation of various proteins associated with cell survival or a combination of both. In this review, we will summarize the available knowledge on the antioxidative property and protective effects of geniposide in DM and cardiovascular disease in the literature and discuss antioxidant mechanisms as well as its potential applications in clinic.

High concentrations of atorvastatin reduce in-vitro function of conventional T and regulatory T cells

Regulatory T cells (T_regs ) modulate the magnitude of immune responses and possess therapeutic potential in an array of immune diseases. Statins reduce the activation and proliferation of conventional T cells (T_cons ), and they seem to up-regulate the frequency and function of T_regs . However, there is a lack of simultaneous evaluation of the in-vitro effect of statins on the functional profile of T_regs versus T_cons . Herein, magnetically purified T_cons and T_regs were stimulated with CD3/CD28/interleukin (IL)-2 in the presence of atorvastatin (ATV) at 1 or 10 µM. The suppressive function of T_regs , the expression of markers associated with T_reg function, activation levels, cytokine production and calcium flux in both subpopulations were assessed by flow cytometry. ATV had no cytotoxic effect on T cells at the concentrations used. Interestingly, 10 µM ATV hampered the suppressive capacity of T_regs . Moreover, this higher concentration reduced the expression of forkhead box protein 3 (FoxP3), cytotoxic T lymphocyte antigen (CTLA-4) and programmed death 1 (PD-1). In T_cons , ATV at 10 µM decreased PD-1 and CD45RO expression. The expression of CD25, CD69, CD95, CD38, CD62L, CCR7 and perforin was not affected in both subpopulations or at any ATV concentrations. Remarkably, 10 µM ATV increased the percentage of tumour necrosis factor (TNF)-α-producing T_regs . Although there was a reduction of calcium flux in T_cons and T_regs , it was only significant in 10 µM ATV-treated T_cons . These results suggested that 10 µM ATV affects the cellular functions of both populations; however, this concentration particularly affected several aspects of T_reg biology: its suppressive function, cytokine production and expression of T_reg -specific markers.

Differential gene expression in human tissue resident regulatory T cells from lung, colon, and blood

As we learn more about how immune responses occur in situ, it is becoming clear that each organ/tissue is characterized with its own anatomy and microenvironment which may affect and even determine the outcome of the immune responses. With emerging data from animal studies showing that regulatory T cells infiltrating non-lymphoid tissues exhibit unique phenotypes and transcriptional signatures and display functions beyond their well-established suppressive roles, there is an urgent need to explore the function of tissue Treg cells in humans. Here we characterized the transcriptome of Treg residing at the human mucosal tissue obtained from the normal area of cancer resections and their peripheral blood counterparts, identifying human lung and colon tissue Treg signature genes and their upstream regulators. Pathway analysis highlighted potential differences in the cross-talk between tissue Treg cells and other non-immune tissue-specific cell types. For example, genes associated with wnt pathway were differentially regulated in lung Treg cells compared to blood or colon indicating a potential role for lung Treg cells in epithelium repair and regeneration. Moreover, we identified several non-coding RNAs specifically expressed by tissue-resident Tregs. These results provide a comprehensive view of lung and colon tissue Treg transcriptional landscape.

Immunomodulatory effect of statins on Regulatory T Lymphocytes in human colorectal cancer is determined by the stage of disease

Colorectal cancer (CRC) is a public health problem worldwide and in Jordan. Statins are cholesterol lowering agents. Beyond their effects, statins use has been reported to reduced risk of several malignances, including CRC. This study aimed to assess the effect of statins on CRC by studying cellular infiltration of Regulatory T Lymphocytes (Tregs) into CRC tissues and their effect on Transforming growth factor beta 1 (TGF-β₁) level and on angiogenesis. Fourty seven specimens (25 statins users vs. 22 non-users) were used. Immunohistochemistry was performed to study Tregs infiltration using their marker, fork head transcription factor, and angiogenesis using CD31 as a marker. TGF-β₁ levels were measured using ELISA. Results revealed that statins use was associated with more Tregs infiltration, less angiogenesis but no difference in TGF-β₁ content in tumor tissue. When results were further stratified according to stage of disease, more Tregs infiltration was significantly noticed in advanced disease but not in early disease. In addition, more angiogenesis inhibition was noticed in early disease but not in advanced disease. Same stage-dependence wasn’t noticed with TGF-β₁ expression. In early disease, reduction of angiogenesis mediated by statins might lead to reduction of tumor aggressiveness. On the other hand, Tregs infiltration into tumor mediated by statins might reduce cancer aggressiveness in advanced disease. These results suggest that statins might be used in the treatment of CRC.

Lipid-driven immunometabolic responses in atherosclerosis

PURPOSE OF REVIEW

Atherosclerosis is a chronic inflammatory disease in which subendothelial infiltration of lipoproteins leads to inflamed lesions in arteries. Despite improvements in secondary prevention, most cardiovascular events cannot be avoided with current therapies. This review focuses on novel mechanistic insights on lipid-driven immune activation, which could pave the way for new anti-inflammatory treatments for atherosclerosis.

RECENT FINDINGS

Immunometabolic interactions can shape the immune response. Within atherosclerotic plaques, macrophages and T cells are the dominant immune cell populations. Using multiple mechanisms, lipoprotein-derived components activate both the innate and adaptive immune systems. Cholesterol crystals and apolipoprotein B-peptides have been shown to activate macrophages and T cells, respectively. Lipoproteins are also important modulators of regulatory T cells that can hamper vascular inflammation. In the liver, T cells can influence hepatic inflammation and lipoprotein metabolism. Hence, there is an intricate crosstalk between the immune system and lipoprotein metabolism.

SUMMARY

Novel treatments are needed to prevent clinical manifestations of atherosclerosis. Improved understanding of lipid-driven immunometabolic responses is likely to reveal new therapeutic targets.

Immunotropic Effects and Proposed Mechanism of Action for 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Inhibitors (Statins)

Inhibitors of HMG-CoA reductase (statins) are the major group of lipid-lowering drugs. Along with hypocholesterolemic activity, statins exhibit anti-inflammatory and immunomodulatory properties that expand their clinical use, particularly, in the treatment of chronic inflammatory and autoimmune disorders. In this review, we critically analyze the data of statin effects on immune cells (e.g., monocytes and T cells) involved in the development of atherosclerosis and other chronic inflammatory diseases. We (i) discuss the properties of statins and routes of cell entry, as well as their major intracellular targets; (ii) evaluate the data on the effects of statins on the subset composition of circulatory monocytes, ability of monocytes to migrate to the site of inflammation (cell motility and expression of adhesion molecules and chemokine receptors), production of cytokines, matrix metalloproteinases, and reactive oxygen species by monocytes/macrophages, and antigen-presenting activity in peripheral blood monocyte-derived dendritic cells; and (iii) summarize the data on the regulation of proliferation and differentiation of various CD4+ T cell subsets (type 1/2/17 helper T cells and regulatory T cells) by statins.

Regulatory T cells as a new therapeutic target for atherosclerosis

Atherosclerosis is an autoimmune disease caused by self- and non-self-antigens contributing to excessive activation of T and B cell immune responses. These responses further aggravate vascular infiammation and promote progression of atherosclerosis and vulnerability to plaques via releasing pro-infiammatory cytokines. Regulatory T cells (Tregs) as the major immunoregulatory cells, in particular, induce and maintain immune homeostasis and tolerance by suppressing the immune responses of various cells such as T and B cells, natural killer (NK) cells, monocytes, and dendritic cells (DCs), as well as by secreting inhibitory cytokines interleukin (IL)-10, IL-35 and transcription growth factor β (TGF-β) in both physiological and pathological states. Numerous evidence demonstrates that reduced numbers and dysfunction of Treg may be involveved in atherosclerosis pathogenesis. Increasing or restoring the numbers and improving the immunosuppressive capacity of Tregs may serve as a fundamental immunotherapy to treat atherosclerotic cardiovascular diseases. In this article, we briefiy present current knowledge of Treg subsets, summarize the relationship between Tregs and atherosclerosis development, and discuss the possibilities of regulating Tregs for prevention of atherosclerosis pathogenesis and enhancement of plaque stability. Although the exact molecular mechanisms of Treg-mediated protection against atherosclerosis remain to be elucidated, the strategies for targeting the regulation of Tregs may provide specific and significant approaches for the prevention and treatment of atherosclerotic cardiovascular diseases.

Linking CD1-Restricted T Cells With Autoimmunity and Dyslipidemia: Lipid Levels Matter

Dyslipidemia, or altered blood lipid content, is a risk factor for developing cardiovascular disease. Furthermore, several autoimmune diseases, including systemic lupus erythematosus, psoriasis, diabetes, and rheumatoid arthritis, are correlated highly with dyslipidemia. One common thread between both autoimmune diseases and altered lipid levels is the presence of inflammation, suggesting that the immune system might act as the link between these related pathologies. Deciphering the role of innate and adaptive immune responses in autoimmune diseases and, more recently, obesity-related inflammation, have been active areas of research. The broad picture suggests that antigen-presenting molecules, which present self-peptides to autoreactive T cells, can result in either aggravation or amelioration of inflammation. However, very little is known about the role of self-lipid reactive T cells in dyslipidemia-associated autoimmune events. Given that a range of autoimmune diseases are linked to aberrant lipid profiles and a majority of lipid-specific T cells are reactive to self-antigens, it is important to examine the role of these T cells in dyslipidemia-related autoimmune ailments and determine if dysregulation of these T cells can be drivers of autoimmune conditions. CD1 molecules present lipids to T cells and are divided into two groups based on sequence homology. To date, most of the information available on lipid-reactive T cells comes from the study of group 2 CD1d-restricted natural killer T (NKT) cells while T cells reactive to group 1 CD1 molecules remain understudied, despite their higher abundance in humans compared to NKT cells. This review evaluates the mechanisms by which CD1-reactive, self-lipid specific T cells contribute to dyslipidemia-associated autoimmune disease progression or amelioration by examining available literature on NKT cells and highlighting recent progress made on the study of group 1 CD1-restricted T cells.

Silencing of Non-POU-domain-containing octamer-binding protein stabilizes atherosclerotic plaque in apolipoprotein E-knockout mice via NF-κB signaling pathway

BACKGROUND

It remains unknown whether Non-POU-domain-containing octamer-binding protein (NonO) plays a causative role in plaque destabilization. We hypothesized that NonO gene silencing may stabilize atherosclerotic plaque by increasing P4Hα1 expression and inhibiting the inflammation.

METHODS AND RESULTS

Vulnerable atherosclerotic plaques were induced in ApoE-/- mice by high fat diet, perivascular collar placement and mental stress. Compared with normal carotid arteries, those contained vulnerable plaques had high NonO expression. In another in vivo experiment, mice contained vulnerable plaques were randomly divided into 5 groups to receive physiological saline, si-N.C-lentivirus (LV), si-NonO-LV, pGC-GFP-LV and NonO-LV, respectively. NonO overexpression increased while NonO silencing decreased the incidence of carotid plaque disruption. NonO overexpression enhanced macrophage infiltration and lipid deposition but reduced the content of vascular smooth muscle cells and collagen in plaques, leading to an increased plaque vulnerability index, whereas NonO silencing exhibited the opposite effect. In addition, NonO overexpression increased the expression of proinflammatory cytokines and matrix metalloproteinases and decreased the expression of P4Hα1 both in vivo and in vitro, whereas NonO silencing showed the contrary effect. NonO co-immunoprecipitated with NF-κB p65, and promoted its nuclear translocation and phosphorylation, and these effects were reversed by NonO silencing.

CONCLUSION

NonO may promote plaque destabilization and increase the incidence of plaque disruption in ApoE-/- mice by inducing the expression of inflammatory cytokines and matrix metalloproteinases and suppressing that of P4Hα1. The mechanism may involve the interaction of NonO with NF-κB leading to enhanced NF-κB nuclear translocation and phosphorylation.

Evolving targets for the treatment of atherosclerosis

Atherosclerosis is a progressive disease of large arteries and a leading cause of cardiovascular diseases and stroke. Chronic inflammation, aberrant immune response, and disturbances to key enzymes involved with lipid metabolism are characteristic features of atherosclerosis. Apart from targeting the derangements in lipid metabolism, therapeutic modulation to regulate chronic inflammation and the immune system response may prove to be very promising strategies in the management of atherosclerosis. In recent years, various targets have been studied for the treatment of atherosclerosis. PCSK9, a serine protease, actively targets the LDL-R and causes lysosomal degradation, which leads to excessive accumulation of LDL-C. Regulatory T cells (Tregs) and Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) affects the adaptive and innate immune response, respectively, and thus, therapeutic intervention of either of these targets would directly modulate disease progression. Advanced atherosclerotic lesions are characterized by an accumulation of apoptotic cells. Cluster of differentiation-47 (CD47), an anti-phagocytic known as the "don't eat me" signaling molecule, inhibits efferocytosis, which causes accumulation of cell debris in plaque. ADAMTS and Notch signaling potentially affect the formation of neointima by modulation of extracellular matrix components such as macrophages and vascular smooth muscle cells. This review provides insights on the molecular targets for therapeutic intervention of atherosclerosis, their effect at various stages of atherosclerosis development, and the therapies that have been designed and currently being evaluated in clinical trials.

Tim-3 inhibits low-density lipoprotein-induced atherogenic responses in human umbilical vein endothelial cells

Endothelial injury and dysfunction followed by endothelial activation and inflammatory cell recruitment are factors contributing to the initiation and progression of atherosclerosis. Oxidized low-density lipoprotein (ox-LDL) promotes inflammation during atherogenesis and lipid deposition in the arterial wall. We observed that stimulation of human umbilical vein endothelial cells (HUVECs) with ox-LDL activated pro-inflammatory cytokine production and apoptosis, inhibited cell migration, and upregulated T-cell immunoglobulin and mucin domain 3 (Tim-3) expression. Tim-3, in turn, protected HUVECs from ox-LDL-induced apoptosis via the JNK pathway and reversed the inhibition of migration. Tim-3 also inhibited ox-LDL-induced inflammatory cytokine production by suppressing NF-κB activation. In addition, Tim-3 increased production of type 2 T helper cells (Th2) and regulatory T cell (Treg)-associated cytokines. Blocking Tim-3 reversed its effects on the inflammatory response to ox-LDL. Thus, Tim-3 signaling may be a “self-control” mechanism in ox-LDL-triggered inflammation in HUVECs. These results identify Tim-3 as a factor in HUVEC activity and suggest its potential in the treatment of atherosclerosis.

Mast cells emerge as mediators of atherosclerosis: Special emphasis on IL-37 inhibition

In atherosclerosis lipoproteins stimulate the innate immune response, leading to the release of inflammatory cytokines and chemokines. Hypercholesterolemia may activate the synthesis and release of inflammatory cytokines such as IL-1, which induces TNF release in mast cells (MCs). IL-1 and IL-1 family members orchestrate a broadening list of inflammatory diseases, including atherosclerosis. MCs are implicated in the pathophysiology of several diseases including allergy and inflammation. Activated MCs, located perivascularly, contribute to inflammation in atherosclerosis by producing inflammatory cytokines. MC IL-1-activation leads to the immediate release of inflammatory chemical mediators and TNF, and late inflammatory compounds such as cytokines. MCs can be activated by exogenous cytokines, antigens, microbial products (LPS) and neurotransmitters and generate IL-1 beta, TNF and several other inflammatory cytokines/chemokines along with PGD2, leukotrienes, histamine and proteases. MCs activated with IL-1 induce selective release of IL-6 without degranulation. TNF emerges as one of the most potent inflammatory cytokines involved in the response due to LDL. Cytokines, such as IL-1, IL-6, IL-33 and TNF, are generated in the inflammatory sites by both macrophages and MCs, mediating atherosclerosis. IL-37 (IL-1 family member 7) binds IL-18Ra chain and acts by an intracellular mechanism down-regulating the expression of pro-inflammatory signals cJun, MAP kinase p38a, STAT transcription factors and p53. Blocking IL-1 with IL-37 alleviates the symptoms in patients with inflammatory diseases including arteriosclerosis. The impact of IL-37 on inflammatory cytokines mediating atherosclerosis is beneficial and protective. However, more studies are needed to better define this mechanism and the safety and tolerability of IL-37.