Genetic inactivation of IL-1 signaling enhances atherosclerotic plaque instability and reduces outward vessel remodeling in advanced atherosclerosis in mice

The Central Role of Interleukin-1 Signalling in the Pathogenesis of Kawasaki Disease Vasculitis: Path to Translation

Kawasaki disease (KD) manifests as an acute febrile condition and systemic vasculitis, the etiology of which remains elusive. Primarily affecting children under 5 years of age, if untreated KD can lead to a significant risk of coronary artery aneurysms and subsequent long-term cardiovascular sequelae, including myocardial ischemia and myocardial infarction. Intravenous immunoglobulin therapy mitigates the risk of aneurysm formation, but a subset of patients exhibit resistance to this treatment, increasing the susceptibility of coronary artery lesions. Furthermore, the absence of a KD-specific diagnostic test or biomarkers complicates early detection and appropriate treatment. Experimental murine models of KD vasculitis have substantially improved our understanding of the disease pathophysiology, revealing the key roles of the NLRP3 inflammasome and interleukin-1 (IL-1) signalling pathway. This review aims to delineate the pathophysiologic findings of KD while summarising the findings for the emerging key role of IL-1β in its pathogenesis, derived from both human data and experimental murine models, and the translational potential of these findings for anti-IL-1 therapies for children with KD.

Whys and Wherefores of Coronary Arterial Positive Remodeling

Positive remodeling (PR) is an atherosclerotic plaque feature defined as an increase in arterial caliber at the level of an atheroma, in response to increasing plaque burden. The mechanisms that lead to its formation are incompletely understood, but its role in coronary atherosclerosis has major clinical implications. Indeed, plaques with PR have elevated risk of provoking acute cardiac events. Hence, PR figures among the high-risk plaque features that cardiac imaging studies should report. This review aims to provide an overview of the current literature on coronary PR. It outlines the pathophysiology of PR, the different techniques used to assess its presence, and the imaging findings associated to PR, on both noninvasive and invasive studies. This review also summarizes clinical observations, trials, and studies, focused on the impact of PR on clinical outcome.

Inflammatory crosstalk impairs phagocytic receptors and aggravates atherosclerosis in clonal hematopoiesis in mice

Clonal hematopoiesis (CH) increases inflammasome-linked atherosclerosis, but the mechanisms by which CH mutant cells transmit inflammatory signals to nonmutant cells are largely unknown. To address this question, we transplanted 1.5% Jak2V617F (Jak2VF) bone marrow (BM) cells with 98.5% WT BM cells into hyperlipidemic Ldlr-/- mice. Low-allele-burden (LAB) mice showed accelerated atherosclerosis with increased features of plaque instability, decreased levels of the macrophage phagocytic receptors c-Mer tyrosine kinase (MERTK) and triggering receptor expressed on myeloid cells 2 (TREM2), and increased neutrophil extracellular traps (NETs). These changes were reversed when Jak2VF BM was transplanted with Il1r1-/- BM. LAB mice with noncleavable MERTK in WT BM showed improvements in necrotic core and fibrous cap formation and reduced NETs. An agonistic TREM2 antibody (4D9) markedly increased fibrous caps in both control and LAB mice, eliminating the difference between the groups. Mechanistically, 4D9 increased TREM2+PDGFB+ macrophages and PDGF receptor-α+ fibroblast-like cells in the cap region. TREM2 and PDGFB mRNA levels were positively correlated in human carotid plaques and coexpressed in macrophages. In summary, low frequencies of Jak2VF mutations promoted atherosclerosis via IL-1 signaling from Jak2VF to WT macrophages and neutrophils, promoting cleavage of phagocytic receptors and features of plaque instability. Therapeutic approaches that stabilize MERTK or TREM2 could promote plaque stabilization, especially in CH- and inflammasome-driven atherosclerosis.

Recent Advances in Targeted Management of Inflammation In Atherosclerosis: A Narrative Review

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality despite effective low-density lipoprotein cholesterol-targeted therapies. This review explores the crucial role of inflammation in the residual risk of ASCVD, emphasizing its impact on atherosclerosis progression and plaque stability. Evidence suggests that high-sensitivity C-reactive protein (hsCRP), and potentially other inflammatory biomarkers, can be used to identify the inflammatory residual ASCVD risk phenotype and may serve as future targets for the development of more efficacious therapeutic approaches. We review the biological basis for the association of inflammation with ASCVD, propose new therapeutic strategies for the use of inflammation-targeted treatments, and discuss current challenges in the implementation of this new treatment paradigm for ASCVD.

The Pathological Mechanisms and Therapeutic Molecular Targets in Arteriovenous Fistula Dysfunction

The number of patients with end-stage renal disease (ESRD) requiring hemodialysis is increasing worldwide. Although arteriovenous fistula (AVF) is the best and most important vascular access (VA) for hemodialysis, its primary maturation failure rate is as high as 60%, which seriously endangers the prognosis of hemodialysis patients. After AVF establishment, the venous outflow tract undergoes hemodynamic changes, which are translated into intracellular signaling pathway cascades, resulting in an outward and inward remodeling of the vessel wall. Outward remodeling refers to the thickening of the vessel wall and the dilation of the lumen to accommodate the high blood flow in the AVF, while inward remodeling is mainly characterized by intimal hyperplasia. More and more studies have shown that the two types of remodeling are closely related in the occurrence and development of, and jointly determining the final fate of, AVF. Therefore, it is essential to investigate the underlying mechanisms involved in outward and inward remodeling for identifying the key targets in alleviating AVF dysfunction. In this review, we summarize the current clinical diagnosis, monitoring, and treatment techniques for AVF dysfunction and discuss the possible pathological mechanisms related to improper outward and inward remodeling in AVF dysfunction, as well as summarize the similarities and differences between the two remodeling types in molecular mechanisms. Finally, the representative therapeutic targets of potential clinical values are summarized.

IL-1β Inhibition Partially Negates the Beneficial Effects of Diet-Induced Atherosclerosis Regression in Mice

BACKGROUND

Thromboembolic events secondary to rupture or erosion of advanced atherosclerotic lesions is the global leading cause of death. The most common and effective means to reduce these major adverse cardiovascular events, including myocardial infarction and stroke, is aggressive lipid lowering via a combination of drugs and dietary modifications. However, we know little regarding the effects of reducing dietary lipids on the composition and stability of advanced atherosclerotic lesions, the mechanisms that regulate these processes, and what therapeutic approaches might augment the benefits of lipid lowering.

METHODS

Smooth muscle cell lineage-tracing Apoe-/- mice were fed a high-cholesterol Western diet for 18 weeks and then a zero-cholesterol standard laboratory diet for 12 weeks before treating them with an IL (interleukin)-1β or control antibody for 8 weeks. We assessed lesion size and remodeling indices, as well as the cellular composition of aortic and brachiocephalic artery lesions, indices of plaque stability, overall plaque burden, and phenotypic transitions of smooth muscle cell and other lesion cells by smooth muscle cell lineage tracing combined with single-cell RNA sequencing, cytometry by time-of-flight, and immunostaining plus high-resolution confocal microscopic z-stack analysis.

RESULTS

Lipid lowering by switching Apoe-/- mice from a Western diet to a standard laboratory diet reduced LDL cholesterol levels by 70% and resulted in multiple beneficial effects including reduced overall aortic plaque burden, as well as reduced intraplaque hemorrhage and necrotic core area. However, contrary to expectations, IL-1β antibody treatment after diet-induced reductions in lipids resulted in multiple detrimental changes including increased plaque burden and brachiocephalic artery lesion size, as well as increasedintraplaque hemorrhage, necrotic core area, and senescence as compared with IgG control antibody-treated mice. Furthermore, IL-1β antibody treatment upregulated neutrophil degranulation pathways but downregulated smooth muscle cell extracellular matrix pathways likely important for the protective fibrous cap.

CONCLUSIONS

Taken together, IL-1β appears to be required for the maintenance of standard laboratory diet-induced reductions in plaque burden and increases in multiple indices of plaque stability.

The novel vaccines targeting interleukin-1 receptor type I

OBJECTIVE

There is mounting evidence indicating that atherosclerosis represents a persistent inflammatory process, characterized by the presence of inflammation at various stages of the disease. Interleukin-1 (IL-1) precisely triggers inflammatory signaling pathways by binding to interleukin-1 receptor type I (IL-1R1). Inhibition of this signaling pathway contributes to the prevention of atherosclerosis and myocardial infarction. The objective of this research is to develop therapeutic vaccines targeting IL-1R1 as a preventive measure against atherosclerosis and myocardial infarction.

METHODS

ILRQβ-007 and ILRQβ-008 vaccines were screened, prepared and then used to immunize high-fat-diet fed ApoE-/- mice and C57BL/6J mice following myocardial infarction. Progression of atherosclerosis in ApoE-/- mice was assessed primarily by oil-red staining of the entire aorta and aortic root, as well as by detecting the extent of macrophage infiltration. The post-infarction cardiac function in C57BL/6J mice were evaluated using cardiac ultrasound and histological staining.

RESULTS

ILRQβ-007 and ILRQβ-008 vaccines stimulated animals to produce high titers of antibodies that effectively inhibited the binding of interleukin-1β and interleukin-1α to IL-1R1. Both vaccines effectively reduced atherosclerotic plaque area, promoted plaque stabilization, decreased macrophage infiltration in plaques and influenced macrophage polarization, as well as decreasing levels of inflammatory factors in the aorta, serum, and ependymal fat in ApoE-/- mice. Furthermore, these vaccines dramatically improved cardiac function and macrophage infiltration in C57BL/6J mice following myocardial infarction. Notably, no significant immune-mediated damage was observed in immunized animals.

CONCLUSION

The vaccines targeting the IL-1R1 would be a novel and promising treatment for the atherosclerosis and myocardial infarction.

Interleukin-1 receptor accessory protein blockade limits the development of atherosclerosis and reduces plaque inflammation

AIMS

The interleukin-1 receptor accessory protein (IL1RAP) is a co-receptor required for signalling through the IL-1, IL-33, and IL-36 receptors. Using a novel anti-IL1RAP-blocking antibody, we investigated the role of IL1RAP in atherosclerosis.

METHODS AND RESULTS

Single-cell RNA sequencing data from human atherosclerotic plaques revealed the expression of IL1RAP and several IL1RAP-related cytokines and receptors, including IL1B and IL33. Histological analysis showed the presence of IL1RAP in both the plaque and adventitia, and flow cytometry of murine atherosclerotic aortas revealed IL1RAP expression on plaque leucocytes, including neutrophils and macrophages. High-cholesterol diet fed apolipoprotein E-deficient (Apoe-/-) mice were treated with a novel non-depleting IL1RAP-blocking antibody or isotype control for the last 6 weeks of diet. IL1RAP blockade in mice resulted in a 20% reduction in subvalvular plaque size and limited the accumulation of neutrophils and monocytes/macrophages in plaques and of T cells in adventitia, compared with control mice. Indicative of reduced plaque inflammation, the expression of several genes related to leucocyte recruitment, including Cxcl1 and Cxcl2, was reduced in brachiocephalic arteries of anti-IL1RAP-treated mice, and the expression of these chemokines in human plaques was mainly restricted to CD68+ myeloid cells. Furthermore, in vitro studies demonstrated that IL-1, IL-33, and IL-36 induced CXCL1 release from both macrophages and fibroblasts, which could be mitigated by IL1RAP blockade.

CONCLUSION

Limiting IL1RAP-dependent cytokine signalling pathways in atherosclerotic mice reduces plaque burden and plaque inflammation, potentially by limiting plaque chemokine production.

The role of the NLRP3 inflammasome and pyroptosis in cardiovascular diseases

An intense, stereotyped inflammatory response occurs in response to ischaemic and non-ischaemic injury to the myocardium. The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a finely regulated macromolecular protein complex that senses the injury and triggers and amplifies the inflammatory response by activation of caspase 1; cleavage of pro-inflammatory cytokines, such as pro-IL-1β and pro-IL-18, to their mature forms; and induction of inflammatory cell death (pyroptosis). Inhibitors of the NLRP3 inflammasome and blockers of IL-1β and IL-18 activity have been shown to reduce injury to the myocardium and pericardium, favour resolution of the inflammation and preserve cardiac function. In this Review, we discuss the components of the NLRP3 inflammasome and how it is formed and activated in various ischaemic and non-ischaemic cardiac pathologies (acute myocardial infarction, cardiac dysfunction and remodelling, atherothrombosis, myocarditis and pericarditis, cardiotoxicity and cardiac sarcoidosis). We also summarize current preclinical and clinical evidence from studies of agents that target the NLRP3 inflammasome and related cytokines.

"How to Release or Not Release, That Is the Question." A Review of Interleukin-1 Cellular Release Mechanisms in Vascular Inflammation

Cardiovascular disease remains the leading cause of death worldwide, characterized by atherosclerotic activity within large and medium-sized arteries. Inflammation has been shown to be a primary driver of atherosclerotic plaque formation, with interleukin-1 (IL-1) having a principal role. This review focuses on the current state of knowledge of molecular mechanisms of IL-1 release from cells in atherosclerotic plaques. A more in-depth understanding of the process of IL-1's release into the vascular environment is necessary for the treatment of inflammatory disease processes, as the current selection of medicines being used primarily target IL-1 after it has been released. IL-1 is secreted by several heterogenous mechanisms, some of which are cell type-specific and could provide further specialized targets for therapeutic intervention. A major unmet challenge is to understand the mechanism before and leading to IL-1 release, especially by cells in atherosclerotic plaques, including endothelial cells, vascular smooth muscle cells, and macrophages. Data so far indicate a heterogeneity of IL-1 release mechanisms that vary according to cell type and are stimulus-dependent. Unraveling this complexity may reveal new targets to block excess vascular inflammation.

Human vascular smooth muscle cells utilise chymase for the atypical cleavage and activation of Interleukin-1β

BACKGROUND AND AIMS

Atherosclerosis and other cardiovascular diseases (CVD) are well established to be both instigated and worsened by inflammation. Indeed, CANTOS formally proved that targeting the inflammatory cytokine IL-1β only could reduce both cardiovascular events and death. However, due to the central role of IL-1β in host defence, blockade increased fatal infections, suggesting targeting key immune mediators over the long natural history of CVD is unsuitable. Thus, discovering alternative mechanisms that generate vascular inflammation may identify more actionable targets.

METHODS

We used primary human VSMCs and a combination of biochemical, pharmacological and molecular biological techniques to generate the data. Human carotid atherosclerotic plaques were also assessed histologically.

RESULTS

We showed that VSMCs expressed and efficiently processed pro-IL-1β to the active form after receiving a single stimulus via IL-1R1 or TLR4. Importantly, pro-IL-1β processing did not utilise inflammasomes or caspases. Unusually, we found that cathepsin C-activated chymase was responsible for cleaving IL-1β in VSMCs, and provided evidence for chymase expression in cultured VSMCs and in the fibrous cap of human plaques. Chymase also efficiently cleaved and activated recombinant pro-IL-1β.

CONCLUSIONS

Thus, VSMCs are efficient activators of IL-1β that do not use canonical inflammasomes or caspases. Hence, this alternative pathway could be targeted for long-term treatment of CVDs, as it is not central to everyday host defence.

Pathogenic pathways and therapeutic targets of inflammation in heart diseases: A focus on Interleukin-1

BACKGROUND

An exuberant and dysregulated inflammatory response contributes to the development and progression of cardiovascular diseases (CVDs).

METHODS

This narrative review includes original articles and reviews published over the past 20 years and found through PubMed. The following search terms (or combination of terms) were considered: "acute pericarditis," "recurrent pericarditis," "myocarditis," "cardiac sarcoidosis," "atherosclerosis," "acute myocardial infarction," "inflammation," "NLRP3 inflammasome," "Interleukin-1" and "treatment."

RESULTS

Recent evidence supports the role of inflammation across a wide spectrum of CVDs including myocarditis, pericarditis, inflammatory cardiomyopathies (i.e. cardiac sarcoidosis) as well as atherosclerotic CVD and heart failure. Interleukins (ILs) are the signalling mediators of the inflammatory response. The NACHT, leucine-rich repeat and pyrin-domain containing protein 3 (NLRP3) inflammasome play a key role in producing IL-1β, the prototypical pro-inflammatory cytokine involved in CVDs. Other pro-inflammatory cytokines (e.g. tumour necrosis factor) have been implicated in cardiac sarcoidosis. As a proof of this, IL-1 blockade has been proven efficacious in pericarditis and chronic coronary syndrome.

CONCLUSION

Tailored strategies aiming at quenching the inflammatory response have emerged as promising to treat CVDs. In this review article, we summarize recent evidence regarding the role of inflammation across a broad spectrum of CVDs. We also review novel evidence regarding targeted therapeutic strategies.

Pathological and Therapeutical Implications of Pyroptosis in Psoriasis and Hidradenitis Suppurativa: A Narrative Review

This manuscript explores the role of pyroptosis, an inflammatory programmed cell death, in the pathogenesis of two chronic dermatoses, psoriasis and hidradenitis suppurativa (HS). The diseases, though clinically diverse, share common pathogenetic pathways involving the unbalanced interaction between the adaptive and innate immune systems. This review focuses on the molecular changes in psoriatic and HS skin, emphasizing the activation of dendritic cells, secretion of interleukins (IL-17, IL-22, and TNF-α), and the involvement of inflammasomes, particularly NLRP3. This manuscript discusses the role of caspases, especially caspase-1, in driving pyroptosis and highlights the family of gasdermins (GSDMs) as key players in the formation of pores leading to cell rupture and the release of proinflammatory signals. This study delves into the potential therapeutic implications of targeting pyroptosis in psoriasis and HS, examining existing medications like biologics and Janus kinase inhibitors. It also reviews the current limitations and challenges in developing therapies that selectively target pyroptosis. Additionally, the manuscript explores the role of pyroptosis in various inflammatory disorders associated with psoriasis and HS, such as inflammatory bowel disease, diabetes mellitus, and cardiovascular disorders. The review concludes by emphasizing the need for further research to fully elucidate the pathomechanisms of these dermatoses and develop effective, targeted therapies.

The role of inflammasomes in human diseases and their potential as therapeutic targets

Inflammasomes are large protein complexes that play a major role in sensing inflammatory signals and triggering the innate immune response. Each inflammasome complex has three major components: an upstream sensor molecule that is connected to a downstream effector protein such as caspase-1 through the adapter protein ASC. Inflammasome formation typically occurs in response to infectious agents or cellular damage. The active inflammasome then triggers caspase-1 activation, followed by the secretion of pro-inflammatory cytokines and pyroptotic cell death. Aberrant inflammasome activation and activity contribute to the development of diabetes, cancer, and several cardiovascular and neurodegenerative disorders. As a result, recent research has increasingly focused on investigating the mechanisms that regulate inflammasome assembly and activation, as well as the potential of targeting inflammasomes to treat various diseases. Multiple clinical trials are currently underway to evaluate the therapeutic potential of several distinct inflammasome-targeting therapies. Therefore, understanding how different inflammasomes contribute to disease pathology may have significant implications for developing novel therapeutic strategies. In this article, we provide a summary of the biological and pathological roles of inflammasomes in health and disease. We also highlight key evidence that suggests targeting inflammasomes could be a novel strategy for developing new disease-modifying therapies that may be effective in several conditions.

Enhanced Akt3 kinase activity reduces atherosclerosis in hyperlipidemic mice in a gender-dependent manner

Akt3 is one of the three members of the serine/threonine protein kinase B (AKT) family, which regulates multiple cellular processes. We have previously demonstrated that global knockout of Akt3 in mice promotes atherogenesis in a macrophage-dependent manner. Whether enhanced Akt3 kinase activity affects atherogenesis is not known. In this study, we crossed atherosclerosis-prone ApoE-/- mice with a mouse strain that has enhanced Akt3 kinase activity (Akt3nmf350) and assessed atherosclerotic lesion formation and the role of macrophages in atherogenesis. Significant reduction in atherosclerotic lesion area and macrophage accumulation in lesions were observed in ApoE-/-/Akt3nmf350 mice fed a Western-type diet. Experiments using chimeric ApoE-/- mice with either ApoE-/-/Akt3nmf350 bone marrow or ApoE-/- bone marrow cells showed that enhanced Akt3 activity specifically in bone marrow-derived cells is atheroprotective. The atheroprotective effect of Akt3nmf350 was more pronounced in male mice. In line with this result, the release of the pro-inflammatory cytokines IL-6, MCP1, TNF-α, and MIP-1α was reduced by macrophages from male but not female ApoE-/-/Akt3nmf350 mice. Levels of IL-6 and TNF-α were also reduced in atherosclerotic lesions of ApoE-/-/Akt3nmf350 male mice compared to ApoE-/- mice. Macrophages from male ApoE-/-/Akt3nmf350 mice were also more resistant to apoptosis in vitro and in vivo and tended to have more pronounced M2 polarization in vitro. These findings demonstrated that enhanced Akt3 kinase activity in macrophages protects mice from atherosclerosis in hyperlipidemic mice in a gender-dependent manner.

Apolipoprotein B and interleukin 1 receptor antagonist: reversing the risk of coronary heart disease

Aims

Epidemiological evidence for the link of interleukin 1 (IL-1) and its inhibition with cardiovascular diseases (CVDs) remains controversial. We aim to investigate the cardiovascular effects of IL-1 receptor antagonist (IL-1Ra) and underlying mechanisms.

Methods

Genetic variants identified from a genome-wide association study involving 30,931 individuals were used as instrumental variables for the serum IL-1Ra concentrations. Genetic associations with CVDs and cardiometabolic risk factors were obtained from international genetic consortia. Inverse-variance weighted method was utilized to derive effect estimates, while supplementary analyses employing various statistical approaches.

Results

Genetically determined IL-1Ra level was associated with increased risk of coronary heart disease (CHD; OR, 1.07; 95% CI: 1.03-1.17) and myocardial infarction (OR, 1.13; 95% CI: 1.04-1.21). The main results remained consistent in supplementary analyses. Besides, IL-1Ra was associated with circulating levels of various lipoprotein lipids, apolipoproteins and fasting glucose. Interestingly, observed association pattern with CHD was reversed when adjusting for apolipoprotein B (OR, 0.84; 95%CI: 0.71-0.99) and slightly attenuated on accounting for other cardiometabolic risk factors. Appropriate lifestyle intervention was found to lower IL-1Ra concentration and mitigate the heightened CHD risk it posed.

Conclusion

Apolipoprotein B represents the key driver, and a potential target for reversal of the causal link between serum IL-1Ra and increased risk of CHD/MI. The combined therapy involving IL-1 inhibition and lipid-modifying treatment aimed at apolipoprotein B merit further exploration.

Thrombin-activated interleukin-1α drives atherogenesis, but also promotes vascular smooth muscle cell proliferation and collagen production

AIMS

Atherosclerosis is driven by multiple processes across multiple body systems. For example, the innate immune system drives both atherogenesis and plaque rupture via inflammation, while coronary artery-occluding thrombi formed by the coagulation system cause myocardial infarction and death. However, the interplay between these systems during atherogenesis is understudied. We recently showed that coagulation and immunity are fundamentally linked by the activation of interleukin-1α (IL-1α) by thrombin, and generated a novel knock-in mouse in which thrombin cannot activate endogenous IL-1α [IL-1α thrombin mutant (IL-1αTM)].

METHODS AND RESULTS

Here, we show significantly reduced atherosclerotic plaque formation in IL-1αTM/Apoe-/- mice compared with Apoe-/- and reduced T-cell infiltration. However, IL-1αTM/Apoe-/- plaques have reduced vascular smooth muscle cells, collagen, and fibrous caps, indicative of a more unstable phenotype. Interestingly, the reduced atherogenesis seen with thrombin inhibition was absent in IL-1αTM/Apoe-/- mice, suggesting that thrombin inhibitors can affect atherosclerosis via reduced IL-1α activation. Finally, bone marrow chimeras show that thrombin-activated IL-1α is derived from both vessel wall and myeloid cells.

CONCLUSIONS

Together, we reveal that the atherogenic effect of ongoing coagulation is, in part, mediated via thrombin cleavage of IL-1α. This not only highlights the importance of interplay between systems during disease and the potential for therapeutically targeting IL-1α and/or thrombin, but also forewarns that IL-1 may have a role in plaque stabilization.

IL-1β inhibition partially negates the beneficial effects of diet-induced lipid lowering

Background

Thromboembolic events secondary to rupture or erosion of advanced atherosclerotic lesions are the leading cause of death in the world. The most common and effective means to reduce these major adverse cardiovascular events (MACE), including myocardial infarction (MI) and stroke, is aggressive lipid lowering via a combination of drugs and dietary modifications. However, little is known regarding the effects of reducing dietary lipids on the composition and stability of advanced atherosclerotic lesions, the mechanisms that regulate these processes, and what therapeutic approaches might augment the benefits of lipid lowering.

Methods

Smooth muscle cell (SMC)-lineage tracing Apoe-/- mice were fed a Western diet (WD) for 18 weeks and then switched to a low-fat chow diet for 12 weeks. We assessed lesion size and remodeling indices, as well as the cellular composition of aortic and brachiocephalic artery (BCA) lesions, indices of plaque stability, overall plaque burden, and phenotypic transitions of SMC, and other lesion cells by SMC-lineage tracing combined with scRNA-seq, CyTOF, and immunostaining plus high resolution confocal microscopic z-stack analysis. In addition, to determine if treatment with a potent inhibitor of inflammation could augment the benefits of chow diet-induced reductions in LDL-cholesterol, SMC-lineage tracing Apoe-/- mice were fed a WD for 18 weeks and then chow diet for 12 weeks prior to treating them with an IL-1β or control antibody (Ab) for 8-weeks.

Results

Lipid-lowering by switching Apoe-/- mice from a WD to a chow diet reduced LDL-cholesterol levels by 70% and resulted in multiple beneficial effects including reduced overall aortic plaque burden as well as reduced intraplaque hemorrhage and necrotic core area. However, contrary to expectations, IL-1β Ab treatment resulted in multiple detrimental changes including increased plaque burden, BCA lesion size, as well as increased cholesterol crystal accumulation, intra-plaque hemorrhage, necrotic core area, and senescence as compared to IgG control Ab treated mice. Furthermore, IL-1β Ab treatment upregulated neutrophil degranulation pathways but down-regulated SMC extracellular matrix pathways likely important for the protective fibrous cap.

Conclusions

Taken together, IL-1β appears to be required for chow diet-induced reductions in plaque burden and increases in multiple indices of plaque stability.

Anti-inflammatory therapies were associated with reduced risk of myocardial infarction in patients with established cardiovascular disease or high cardiovascular risks: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

We aimed to evaluate the association between anti-inflammatory therapies and the incidence of cardiovascular events in patients with established cardiovascular disease (CVD) or high cardiovascular risks.

METHODS

Literature retrieval was conducted in PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials and Clinicaltrial.gov website from the inception to December 2022. Randomized controlled trials comparing anti-inflammatory therapies with placebo in patients with established CVD or high cardiovascular risks were included. The results of the meta-analysis were computed as the risk ratio (RR) with 95% confidence interval (CI).

RESULTS

Compared with placebo, anti-inflammatory therapies were associated with decreased incidence of myocardial infarction (MI) (RR = 0.93, 95% CI, 0.88 to 0.98), which was mainly driven by therapies targeting central IL-6 signaling pathway (RR = 0.83, 95% CI, 0.74 to 0.93). IL-1 inhibitors treatment was associated with reduced risks of heart failure (RR = 0.38, 95% CI, 0.18 to 0.80) while lower incidence of stroke was observed in patients with colchicine treatment (RR = 0.47, 95% CI, 0.28 to 0.77). MI events were less frequent in patients over 65 years of age (RR = 0.90, 95% CI, 0.83 to 0.98) or with follow-up duration over 1 year (RR = 0.90, 95% CI, 0.85 to 0.96) when comparing anti-inflammatory therapies with placebo.

CONCLUSIONS

Anti-inflammatory therapies, especially those targeting the central IL-6 signaling pathway, may serve as promising treating strategies to ameliorate the risk of MI. IL-1 inhibitor and colchicine were associated with decreased risks of heart failure and stroke, respectively. MI risk reduction by anti-inflammatory therapies seemed to be more prominent in older patients with long follow-up duration.

The interleukin-1 receptor type-1 in disturbed flow-induced endothelial mesenchymal activation

Introduction

Atherosclerosis is a progressive disease that develops in areas of disturbed flow (d-flow). Progressive atherosclerosis is characterized by bulky plaques rich in mesenchymal cells and high-grade inflammation that can rupture leading to sudden cardiac death or acute myocardial infarction. In response to d-flow, endothelial cells acquire a mesenchymal phenotype through endothelial-to-mesenchymal transition (EndMT). However, the signaling intermediaries that link d-flow to EndMT are incompletely understood.

Methods and Results

In this study we found that in human atherosclerosis, cells expressing SNAI1 (Snail 1, EndMT transcription factor) were highly expressed within the endothelial cell (EC) layer and in the pre-necrotic areas in unstable lesions, whereas stable lesions did not show any SNAI1 positive cells, suggesting a role for EndMT in lesion instability. The interleukin-1 (IL-1), which signals through the type-I IL-1 receptor (IL-1R1), has been implicated in plaque instability and linked to EndMT formation in vitro. Interestingly, we observed an association between SNAI1 and IL-1R1 within ECs in the unstable lesions. To establish the causal relationship between EndMT and IL-1R1 expression, we next examined IL-1R1 levels in our Cre-lox endothelial-specific lineage tracing mice. IL-1R1 and Snail1 were highly expressed in ECs under atheroprone compared to athero-protective areas, and oscillatory shear stress (OSS) increased IL-1R1 protein and mRNA levels in vitro. Exposure of ECs to OSS resulted in loss of their EC markers and higher induction of EndMT markers. By contrast, genetic silencing of IL-1R1 significantly reduced the expression of EndMT markers and Snail1 nuclear translocation, suggesting a direct role for IL-1R1 in d-flow-induced EndMT. In vivo, re-analysis of scRNA-seq datasets in carotid artery exposed to d-flow confirmed the IL-1R1 upregulation among EndMT population, and in our partial carotid ligation model of d-flow, endothelial cell specific IL-1R1 KO significantly reduced SNAI1 expression.

Discussion

Global inhibition of IL-1 signaling in atherosclerosis as a therapeutic target has recently been tested in the completed CANTOS trial, with promising results. However, the data on IL-1R1 signaling in different vascular cell-types are inconsistent. Herein, we show endothelial IL-1R1 as a novel mechanosensitive receptor that couples d-flow to IL-1 signaling in EndMT.

Vascular Ageing: Mechanisms, Risk Factors, and Treatment Strategies

Ageing constitutes the biggest risk factor for poor health and adversely affects the integrity and function of all the cells, tissues, and organs in the human body. Vascular ageing, characterised by vascular stiffness, endothelial dysfunction, increased oxidative stress, chronic low-grade inflammation, and early-stage atherosclerosis, may trigger or exacerbate the development of age-related vascular diseases, which each year contribute to more than 3.8 million deaths in Europe alone and necessitate a better understanding of the mechanisms involved. To this end, a large number of recent preclinical and clinical studies have focused on the exponential accumulation of senescent cells in the vascular system and paid particular attention to the specific roles of senescence-associated secretory phenotype, proteostasis dysfunction, age-mediated modulation of certain microRNA (miRNAs), and the contribution of other major vascular risk factors, notably diabetes, hypertension, or smoking, to vascular ageing in the elderly. The data generated paved the way for the development of various senotherapeutic interventions, ranging from the application of synthetic or natural senolytics and senomorphics to attempt to modify lifestyle, control diet, and restrict calorie intake. However, specific guidelines, considering the severity and characteristics of vascular ageing, need to be established before widespread use of these agents. This review briefly discusses the molecular and cellular mechanisms of vascular ageing and summarises the efficacy of widely studied senotherapeutics in the context of vascular ageing.

Epigenetic Reader Bromodomain-Containing Protein 4 in Aging-Related Vascular Pathologies and Diseases: Molecular Basis, Functional Relevance, and Clinical Potential

Aging is a key independent risk factor of various vascular diseases, for which the regulatory mechanisms remain largely unknown. Bromodomain-containing protein 4 (BRD4) is a member of the Bromodomain and Extra-Terminal domain (BET) family and is an epigenetic reader playing diverse roles in regulating transcriptional elongation, chromatin remodeling, DNA damage response, and alternative splicing in various cells and tissues. While BRD4 was initially recognized for its involvement in cancer progression, recent studies have revealed that the aberrant expression and impaired function of BRD4 were highly associated with aging-related vascular pathology, affecting multiple key biological processes in the vascular cells and tissues, providing new insights into the understanding of vascular pathophysiology and pathogenesis of vascular diseases. This review summarizes the recent advances in BRD4 biological function, and the progression of the studies related to BRD4 in aging-associated vascular pathologies and diseases, including atherosclerosis, aortic aneurism vascular neointima formation, pulmonary hypertension, and essential hypertension, providing updated information to advance our understanding of the epigenetic mechanisms in vascular diseases during aging and paving the way for future research and therapeutic approaches.

Oridonin supplementation attenuates atherosclerosis via NLRP-3 inflammasome pathway suppression

Atherosclerosis, a long-term inflammatory and immune condition affecting medium- and large-sized arteries, results in the thickening of artery walls and the accumulation of inflammatory cells and fatty streaks that establish fibrous capsules with macrophages at the site of injury. Atherosclerosis has a major impact on the pathogenesis of cardiovascular diseases. Oridonin has been shown to exclusively inhibit the NLRP3 inflammasome without affecting the activation of AIM-2 or NLRC-4 inflammasomes. The current study aimed to evaluate how adding Oridonin to a diet impacts the onset of atherosclerosis. Twenty-one male rabbits weighing 1.5 to 2.0 kg were included in the study. The rabbits were kept in controlled environmental conditions and divided into three groups: a normal control group fed a conventional chow diet, an atherogenic control group fed a high-cholesterol diet (2% cholesterol-rich), and an Oridonin-treated group (Ori) fed an atherogenic diet supplemented with Oridonin (20 mg/kg) administered orally once daily. Compared to animals on a normal diet, an atherogenic diet was associated with a statistically significant (p=0.001) increase in the mean expression of the NLRP3 inflammasome mRNA. The Oridonin-treated group showed a statistically significant (p=0.001) decline in the mean expression of NLRP3 inflammasome mRNA compared to the atherogenic group. Furthermore, the initial atherosclerotic lesion in the group treated with Oridonin was statistically (p=0.001) less severe compared to the atherogenic group. Finally, Ori treated group had significantly (p≤0.001) lower IL-1B immunostaining intensity than the atherogenic group (mean rank 14.5,25 respectively). The study concluded that Oridonin supplementation resulted in less severe initial atherosclerotic lesions, likely due to the suppression of NLRP3 inflammasome and the anti-inflammatory effect through the downregulation of IL1B expression.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

Inflammasomes and Atherosclerosis: a Mixed Picture

The CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcome Study) and colchicine trials suggest an important role of inflammasomes and their major product IL-1β (interleukin 1β) in human atherosclerotic cardiovascular disease. Moreover, studies in mouse models indicate a causal role of inflammasomes and IL-1β in atherosclerosis. However, recent studies have led to a more granular view of the role of inflammasomes in atherosclerosis. Studies in hyperlipidemic mouse models suggest that prominent activation of the NLRP3 inflammasome requires a second hit such as defective cholesterol efflux, defective DNA repair, clonal hematopoiesis or diabetes. Similarly in humans some mutations promoting clonal hematopoiesis increase coronary artery disease risk in part by promoting inflammasome activation. Recent studies in mice and humans point to a wider role of the AIM2 (absent in melanoma 2) inflammasome in promoting cardiovascular disease including in some forms of clonal hematopoiesis and diabetes. These developments suggest a precision medicine approach in which treatments targeting inflammasomes or IL-1β might be best employed in clinical settings involving increased inflammasome activation.

Nicotine exacerbates atherosclerosis and plaque instability via NLRP3 inflammasome activation in vascular smooth muscle cells

Rationale: Nicotine has been reported to be a strong risk factor for atherosclerosis. However, the underlying mechanism by which nicotine controls atherosclerotic plaque stability remain largely unknown. Objective: The aim of this study was to evaluate the impact of lysosomal dysfunction mediated NLRP3 inflammasome activation in vascular smooth muscle cell (VSMC) on atherosclerotic plaque formation and stability in advanced atherosclerosis at the brachiocephalic arteries (BA). Methods and Results: Features of atherosclerotic plaque stability and the markers for NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome were monitored in the BA from nicotine or vehicle-treated apolipoprotein E deficient (Apoe-/-) mice fed with Western-type diet (WD). Nicotine treatment for 6 weeks accelerated atherosclerotic plaque formation and enhanced the hallmarks of plaque instability in BA of Apoe-/- mice. Moreover, nicotine elevated interleukin 1 beta (IL-1β) in serum and aorta and was preferred to activate NLRP3 inflammasome in aortic vascular smooth muscle cells (VSMC). Importantly, pharmacological inhibition of Caspase1, a key downstream target of NLRP3 inflammasome complex, and genetic inactivation of NLRP3 significantly restrained nicotine-elevated IL-1β in serum and aorta, as well as nicotine-stimulated atherosclerotic plaque formation and plaque destabilization in BA. We further confirmed the role of VSMC-derived NLRP3 inflammasome in nicotine-induced plaque instability by using VSMC specific TXNIP (upstream regulator of NLRP3 inflammasome) deletion mice. Mechanistic study further showed that nicotine induced lysosomal dysfunction resulted in cathepsin B cytoplasmic release. Inhibition or knockdown of cathepsin B blocked nicotine-dependent inflammasome activation. Conclusions: Nicotine promotes atherosclerotic plaque instability by lysosomal dysfunction-mediated NLRP3 inflammasome activation in vascular smooth muscle cells.

IL-1 in Abdominal Aortic Aneurysms

Abdominal Aortic Aneurysms (AAA) remain a clinically devastating disease with no effective medical treatment therapy. AAAs are characterized by immune cell infiltration, smooth muscle cell apoptosis, and extracellular matrix degradation. Interleukin-1 (IL-1) has been shown to play role in AAA associated inflammation through immune cell recruitment and activation, endothelial dysfunction, production of reactive oxygen species (ROS), and regulation of transcription factors of additional inflammatory mediators. In this review, we will discuss the principles of IL-1 signaling, its role in AAA specific inflammation, and regulators of IL-1 signaling. Additionally, we will discuss the influence of genetic and pharmacological inhibitors of IL-1 on experimental AAAs. Evidence suggests that IL-1 may prove to be a potential therapeutic target in the management of AAA disease.

The IL-1 Family and Its Role in Atherosclerosis

The IL-1 superfamily of cytokines is a central regulator of immunity and inflammation. The family is composed of 11 cytokines (with agonist, antagonist, and anti-inflammatory properties) and 10 receptors, all tightly regulated through decoy receptor, receptor antagonists, and signaling inhibitors. Inflammation not only is an important physiological response against infection and injury but also plays a central role in atherosclerosis development. Several clinical association studies along with experimental studies have implicated the IL-1 superfamily of cytokines and its receptors in the pathogenesis of cardiovascular disease. Here, we summarize the key features of the IL-1 family, its role in immunity and disease, and how it helps shape the development of atherosclerosis.

Correlation between platelet-derived growth factor-B gene polymorphism and coronary heart disease

OBJECT

The aim of the present work was to investigate the correlation of plasma platelet-derived growth factor (PDGF)-BB level and single nucleotide polymorphism (SNP, rs1800817 and rs2285094) of PDGF-B gene with the onset and stability condition of coronary heart disease (CHD).

METHODS

Totally, 335 subjects were included in and divided into CHD (n = 247) and control group (n = 88) according to coronary angiography. Besides, the patients in the CHD group were divided into acute coronary syndrome (ACS) group (n = 165) and stable angina pectoria (SAP) group (n = 82), based on CHD stability condition. The plasma PDGF-BB level was measured by ELISA, and the genotype of PDGF-B was examined through qPCR assay.

RESULTS

The PDGF-BB level was positively correlated with hsCRP level (r = 0.149, p < 0.05). The genotype frequencies of SNP rs1800817 and rs2285094 match Hardy-Weinberg equilibrium. There was weak linkage disequilibrium between SNP rs1800817 and rs2285094: D' = 0.419, r²  = 0.04, which has no correlation with CHD. There was no statistical difference in plasma PDGF-BB level among different genotypes in rs1800817 and rs2285094. There were no differences in the plasma PDGF-BB level among patients with any genotype of SNP rs1800817 and rs2285094, no matter how it was grouped. Logistic regression results indicated that the plasma PDGF-BB level was the independent risk factor of CHD onset (OR = 1.003, 95% CI 1.001-1.006, p = 0.014).

CONCLUSIONS

High plasma PDGF-BB level is the risk factor of CHD and has correlation with instability of CHD. The plasma PDGF-BB level change may be related to inflammatory response. PDGF-B gene rs1800817 and rs2285094 polymorphisms are not correlated with CHD.

The Role of Colchicine in Atherosclerosis: From Bench to Bedside

Inflammation is a key feature of atherosclerosis. The inflammatory process is involved in all stages of disease progression, from the early formation of plaque to its instability and disruption, leading to clinical events. This strongly suggests that the use of anti-inflammatory agents might improve both atherosclerosis progression and cardiovascular outcomes. Colchicine, an alkaloid derived from the flower Colchicum autumnale, has been used for years in the treatment of inflammatory pathologies, including Gout, Mediterranean Fever, and Pericarditis. Colchicine is known to act over microtubules, inducing depolymerization, and over the NLRP3 inflammasome, which might explain its known anti-inflammatory properties. Recent evidence has shown the therapeutic potential of colchicine in the management of atherosclerosis and its complications, with limited adverse effects. In this review, we summarize the current knowledge regarding colchicine mechanisms of action and pharmacokinetics, as well as the available evidence on the use of colchicine for the treatment of coronary artery disease, covering basic, translational, and clinical studies.

The role of cytokines, adhesion molecules, and toll-like receptors in atherosclerosis progression: the effect of Atorvastatin

Inflammatory cytokines, cell adhesion molecules, and toll-like receptors (TLRs) play an important role in atherosclerosis. The aim of this study was to further evaluate the role of inflammatory cytokines, cell adhesion molecules, and toll-like receptors in atherosclerosis. Forty local breed domestic male rabbits were divided randomly into 4 groups, 10 rabbits each. Group I was the control group, group II received a high cholesterol diet, group III received the drug solvent dimethyl sulfoxide (DMSO), and group IV received Atorvastatin (3.5 mg/kg/day). Blood samples were collected at 0 times, 5 weeks, and at the end of 10 weeks. TLRs expression on monocyte was measured by flow cytometry, IL-10, IL-17, IL-1β, intracellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM) were measured by ELISA. In group II, a high cholesterol diet led to a statistically significant elevation of lipids profile (TC, TG, and LDL) at both 5 weeks and 10 weeks compared to the control. The expression of TLRs was also increased compared to the control (13.53±2.5 to 25.79±6.5). The intimal thickness increased from 103.46±13.85 to 248.43±11.11. IL-17 increased significantly from 3.4±0.4 to 7.7±1.00, and IL-1β increased from 1.04±0.19 to 9.66±1.4 (P 0.05) at 10 weeks. ICAM and VCAM increased from 1.7±0.16 to 8.2±0.74 and from 0.89±0.07 to 5.2±0.45, respectively. Atorvastatin significantly reduced TLRs at 10 weeks to 21.98±3.4 and intimal thickness to 191.6±15.59. IL-17, IL-1β, ICAM, and VCAM were significantly reduced by Atorvastatin. Cytokines, cellular adhesion molecules, and probably TLRs have a role in the pathogenesis of hyperlipidemia and atherosclerosis.

Pyroptosis: Role and Mechanisms in Cardiovascular Disease

Cardiovascular disease (CVD) is a common disease that poses a huge threat to human health. Irreversible cardiac damage due to cardiomyocyte death and lack of regenerative capacity under stressful conditions, ultimately leading to impaired cardiac function, is the leading cause of death worldwide. The regulation of cardiomyocyte death plays a crucial role in CVD. Previous studies have shown that the modes of cardiomyocyte death include apoptosis and necrosis. However, another new form of death, pyroptosis, plays an important role in CVD pathogenesis. Pyroptosis induces the amplification of inflammatory response, increases myocardial infarct size, and accelerates the occurrence of cardiovascular disease, and the control of cardiomyocyte pyroptosis holds great promise for the treatment of cardiovascular disease. In this paper, we summarized the characteristics, occurrence and regulation mechanism of pyroptosis are reviewed, and also discussed its role and mechanisms in CVD, such as atherosclerosis (AS), myocardial infarction (MI), arrhythmia and cardiac hypertrophy.

Inflammatory Mediators in Atherosclerotic Vascular Remodeling

Atherosclerotic vascular disease remains the most common cause of ischemia, myocardial infarction, and stroke. Vascular function is determined by structural and functional properties of the arterial vessel wall, which consists of three layers, namely the adventitia, media, and intima. Key cells in shaping the vascular wall architecture and warranting proper vessel function are vascular smooth muscle cells in the arterial media and endothelial cells lining the intima. Pathological alterations of this vessel wall architecture called vascular remodeling can lead to insufficient vascular function and subsequent ischemia and organ damage. One major pathomechanism driving this detrimental vascular remodeling is atherosclerosis, which is initiated by endothelial dysfunction allowing the accumulation of intimal lipids and leukocytes. Inflammatory mediators such as cytokines, chemokines, and modified lipids further drive vascular remodeling ultimately leading to thrombus formation and/or vessel occlusion which can cause major cardiovascular events. Although it is clear that vascular wall remodeling is an elementary mechanism of atherosclerotic vascular disease, the diverse underlying pathomechanisms and its consequences are still insufficiently understood.

Ebselen abolishes vascular dysfunction in influenza A virus-induced exacerbations of cigarette smoke-induced lung inflammation in mice

People with chronic obstructive pulmonary disease (COPD) are susceptible to respiratory infections which exacerbate pulmonary and/or cardiovascular complications, increasing their likelihood of death. The mechanisms driving these complications remain unknown but increased oxidative stress has been implicated. Here we investigated whether influenza A virus (IAV) infection, following chronic cigarette smoke (CS) exposure, worsens vascular function and if so, whether the antioxidant ebselen alleviates this vascular dysfunction. Male BALB/c mice were exposed to either room air or CS for 8 weeks followed by inoculation with IAV (Mem71, 1 × 104.5 pfu). Mice were treated with ebselen (10 mg/kg) or vehicle (5% w/v CM-cellulose in water) daily. Mice were culled 3- and 10-days post-infection, and their lungs lavaged to assess inflammation. The thoracic aorta was excised to investigate endothelial and smooth muscle dilator responses, expression of key vasodilatory and oxidative stress modulators, infiltrating immune cells and vascular remodelling. CS increased lung inflammation and caused significant vascular endothelial dysfunction, which was worsened by IAV infection. CS-driven increases in vascular oxidative stress, aortic wall remodelling and suppression of endothelial nitric oxide synthase (eNOS) were not affected by IAV infection. CS and IAV infection significantly enhanced T cell recruitment into the aortic wall. Ebselen abolished the exaggerated lung inflammation, vascular dysfunction and increased T cell infiltration in CS and IAV-infected mice. Our findings showed that ebselen treatment abolished vascular dysfunction in IAV-induced exacerbations of CS-induced lung inflammation indicating it may have potential for the treatment of cardiovascular comorbidities seen in acute exacerbations of COPD (AECOPD).

Emerging Roles of Inflammasomes in Cardiovascular Diseases

Cardiovascular diseases are known as the leading cause of morbidity and mortality worldwide. As an innate immune signaling complex, inflammasomes can be activated by various cardiovascular risk factors and regulate the activation of caspase-1 and the production and secretion of proinflammatory cytokines such as IL-1β and IL-18. Accumulating evidence supports that inflammasomes play a pivotal role in the progression of atherosclerosis, myocardial infarction, and heart failure. The best-known inflammasomes are NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes, among which NLRP3 inflammasome is the most widely studied in the immune response and disease development. This review focuses on the activation and regulation mechanism of inflammasomes, the role of inflammasomes in cardiovascular diseases, and the research progress of targeting NLRP3 inflammasome and IL-1β for related disease intervention.

Smad3 regulates smooth muscle cell fate and mediates adverse remodeling and calcification of the atherosclerotic plaque

Atherosclerotic plaques consist mostly of smooth muscle cells (SMC), and genes that influence SMC phenotype can modulate coronary artery disease (CAD) risk. Allelic variation at 15q22.33 has been identified by genome-wide association studies to modify the risk of CAD and is associated with the expression of SMAD3 in SMC. However, the mechanism by which this gene modifies CAD risk remains poorly understood. Here we show that SMC-specific deletion of Smad3 in a murine atherosclerosis model resulted in greater plaque burden, more outward remodelling and increased vascular calcification. Single-cell transcriptomic analyses revealed that loss of Smad3 altered SMC transition cell state toward two fates: a SMC phenotype that governs both vascular remodelling and recruitment of inflammatory cells, as well as a chondromyocyte fate. Together, the findings reveal that Smad3 expression in SMC inhibits the emergence of specific SMC phenotypic transition cells that mediate adverse plaque features, including outward remodelling, monocyte recruitment, and vascular calcification.

Chronic obstructive pulmonary disease and atherosclerosis: common mechanisms and novel therapeutics

Chronic obstructive pulmonary disease (COPD) and atherosclerosis are chronic irreversible diseases, that share a number of common causative factors including cigarette smoking. Atherosclerosis drastically impairs blood flow and oxygen availability to tissues, leading to life-threatening outcomes including myocardial infarction (MI) and stroke. Patients with COPD are most likely to die as a result of a cardiovascular event, with 30% of all COPD-related deaths being attributed to cardiovascular disease (CVD). Both atherosclerosis and COPD involve significant local (i.e. lung, vasculature) and systemic inflammation and oxidative stress, of which current pharmacological treatments have limited efficacy, hence the urgency for the development of novel life-saving therapeutics. Currently these diseases must be treated individually, with no therapies available that can effectively reduce the likelihood of comorbid CVD other than cessation of cigarette smoking. In this review, the important mechanisms that drive atherosclerosis and CVD in people with COPD are explained and we propose that modulation of both the oxidative stress and the inflammatory burden will provide a novel therapeutic strategy to treat both the pulmonary and systemic manifestations related to these diseases.

ZEB2 Shapes the Epigenetic Landscape of Atherosclerosis

BACKGROUND

Smooth muscle cells (SMCs) transition into a number of different phenotypes during atherosclerosis, including those that resemble fibroblasts and chondrocytes, and make up the majority of cells in the atherosclerotic plaque. To better understand the epigenetic and transcriptional mechanisms that mediate these cell state changes, and how they relate to risk for coronary artery disease (CAD), we have investigated the causality and function of transcription factors at genome-wide associated loci.

METHODS

We used CRISPR-Cas 9 genome and epigenome editing to identify the causal gene and cells for a complex CAD genome-wide association study signal at 2q22.3. Single-cell epigenetic and transcriptomic profiling in murine models and human coronary artery smooth muscle cells were used to understand the cellular and molecular mechanism by which this CAD risk gene exerts its function.

RESULTS

CRISPR-Cas 9 genome and epigenome editing showed that the complex CAD genetic signals within a genomic region at 2q22.3 lie within smooth muscle long-distance enhancers for ZEB2, a transcription factor extensively studied in the context of epithelial mesenchymal transition in development of cancer. Zeb2 regulates SMC phenotypic transition through chromatin remodeling that obviates accessibility and disrupts both Notch and transforming growth factor β signaling, thus altering the epigenetic trajectory of SMC transitions. SMC-specific loss of Zeb2 resulted in an inability of transitioning SMCs to turn off contractile programing and take on a fibroblast-like phenotype, but accelerated the formation of chondromyocytes, mirroring features of high-risk atherosclerotic plaques in human coronary arteries.

CONCLUSIONS

These studies identify ZEB2 as a new CAD genome-wide association study gene that affects features of plaque vulnerability through direct effects on the epigenome, providing a new therapeutic approach to target vascular disease.

Key Roles of Inflammation in Atherosclerosis: Mediators Involved in Orchestrating the Inflammatory Response and Its Resolution in the Disease Along with Therapeutic Avenues Targeting Inflammation

Inflammation is a critical driver of all stages of atherosclerosis, from lesion development to plaque rupture. Cytokines are mediators of the immune response and in atherosclerosis, the balance of anti- and pro-inflammatory cytokines is tipped in favor of the latter, resulting in persistent and unresolved inflammation. Although reducing plasma cholesterol levels mainly via the use of statins has positively impacted patient outcomes and reduced mortality rates, the presence of significant residual inflammation and cardiovascular risk posttherapy emphasizes the prevailing risk of primary and secondary events driven by inflammation independently of hyperlipidemia. Given the dominant role of inflammation in driving pathogenesis, alternative therapeutic avenues beyond targeting lowering of plasma lipids are required. This chapter will discuss the role of inflammation and pro-inflammatory cytokines in driving atherogenesis and disease progression, the therapeutic potential of targeting cytokines for atherosclerosis and promising avenues in this area.

Mitochondrial uncoupling protein 1 antagonizes atherosclerosis by blocking NLRP3 inflammasome-dependent interleukin-1β production

Mitochondrial uncoupling protein 1 (UCP1) is the hallmark of brown adipocytes responsible for cold- and diet-induced thermogenesis. Here, we report a previously unidentified role of UCP1 in maintaining vascular health through its anti-inflammatory actions possibly in perivascular adipose tissue. UCP1 deficiency exacerbates dietary obesity-induced endothelial dysfunction, vascular inflammation, and atherogenesis in mice, which was not rectified by reconstitution of UCP1 in interscapular brown adipose tissue. Mechanistically, lack of UCP1 augments mitochondrial membrane potential and mitochondrial superoxide, leading to hyperactivation of the NLRP3-inflammasome and caspase-1–mediated maturation of interleukin-1β (IL-1β). UCP1 deficiency–evoked deterioration of vascular dysfunction and atherogenesis is reversed by IL-1β neutralization or a chemical mitochondrial uncoupler. Furthermore, UCP1 knockin pigs (which lack endogenous UCP1) are refractory to vascular inflammation and coronary atherosclerosis. Thus, UCP1 acts as a gatekeeper to prevent NLRP3 inflammasome activation and IL-1β production in the vasculature, thereby conferring a protective effect against cardiovascular diseases.

Long non‑coding RNA AL355711 promotes smooth muscle cell migration through the ABCG1/MMP3 pathway

Atherosclerosis and related cardiovascular diseases pose severe threats to human health worldwide. There is evidence to suggest that at least 50% of foam cells in atheromas are derived from vascular smooth muscle cells (VSMCs); the first step in this process involves migration to human atherosclerotic lesions. Long non‑coding RNAs (lncRNAs) have been found to play significant roles in diverse biological processes. The present study aimed to investigate the role of lncRNAs in VSMCs. The expression of lncRNAs or mRNAs was detected using reverse transcription‑quantitative polymerase chain reaction. The Gene Expression Omnibus datasets in the NCBI portal were searched using the key words 'Atherosclerosis AND tissue AND Homo sapiens' and the GSE12288 dataset. Gene expression in circulating leukocytes was measured to identify patients with coronary artery disease (CAD) or controls, and used to analyze the correlation coefficient and expression profiles. The protein level of ATP‑binding cassette sub‑family G member 1 (ABCG1) and matrix metalloproteinase (MMP)3 was determined using immunohistochemistry and western blot analysis. The analysis of mouse aortic roots was performed using Masson's and Oil Red O staining. The expression of lncRNA AL355711, ABCG1 and MMP3 was found to be higher in human atherosclerotic plaques or in patients with atherosclerotic CAD. The correlation analysis revealed that ABCG1 may be involved in the regulation between lncRNA AL355711 and MMP3 in atherosclerotic CAD. The knockdown of lncRNA AL355711 inhibited ABCG1 transcription and smooth muscle cell migration. In addition, lncRNA AL355711 was found to regulate MMP3 expression through the ABCG1 pathway. The expression of ABCG1 and MMP3 was found to be high in an animal model of atherosclerosis. The results indicated that lncRNA AL355711 promoted VSMC migration and atherosclerosis partly via the ABCG1/MMP3 pathway. On the whole, the present study demonstrates that the inhibition of lncRNA AL355711 may serve as a novel therapeutic target for atherosclerosis. lncRNA AL355711 in circulating leukocytes may be a novel biomarker for atherosclerotic CAD.

NLRP3 Inflammasome Mediates Immune-Stromal Interactions in Vasculitis

[Figure: see text].

NLRP3 inflammasome and IL-1β pathway in type 2 diabetes and atherosclerosis: Friend or foe?

Type 2 diabetes and atherosclerosis have gradually garnered great attention as inflammatory diseases. Previously, the fact that Interleukin-1β (IL-1β) accelerates the development of type 2 diabetes and atherosclerosis has been proved in animal experiments and clinical trials. However, the continued studies found that the effect of IL-1β on type 2 diabetes and atherosclerosis is much more complicated than the negative impact. Nucleotide-binding oligomerization domain and leucine-rich repeat pyrin 3 domain (NLRP3) inflammasome, whose activation and assembly significantly affect the release of IL-1β, is a crucial effector activated by a variety of metabolites. The diversity of NLRP3 activation mode is one of the fundamental reasons for the intricate effects on the progression of type 2 diabetes and atherosclerosis, providing many new insights for us to intervene in metabolic diseases. This review focuses on how NLRP3 inflammasome affects the progression of type 2 diabetes and atherosclerosis and what opportunities and challenges it can bring us.

Comprehensive analysis of dysregulated genes associated with atherosclerotic plaque destabilization

Atherosclerotic plaque destabilization is a dominating cause of acute cardiovascular events such as myocardial infarction and stroke. This study aims to identify genetic biomarkers related to atherosclerotic plaque destabilization using bioinformatics. Three transcriptome datasets of human carotid atherosclerotic plaque samples were downloaded from ArrayExpress and Gene Expression Omnibus databases, including E-MATB-2055, E-TABM-190, and GSE120521. With Robust Rank Aggregation analysis, we documented 46 differentially expressed genes between stable and unstable/ruptured plaques. Functional enrichment analysis using DAVID tool demonstrated that these genes were mainly related to biological functions such as extracellular matrix disassembly, collagen catabolic process, response to mechanical stimulus, and PPAR signaling pathway. A protein-protein interaction network for the differentially expressed genes was constructed, and eight pivotal genes (ITGAM, MMP9, PLAUR, CCR1, CD163, CD36, ADAM8, and IL1RN) were obtained from the network with a connective degree > 5. The expression patterns of these hub differentially expressed genes could be verified in atherosclerotic plaque samples with intraplaque hemorrhage. Using gene set variation analysis, the eight genes were integrated to generate an atherosclerotic plaque destabilization score, which showed a high performance in not only discriminating individuals with myocardial infarction from those with stable coronary illness, but also in predicting future acute cardiovascular events in atherosclerotic patients. In conclusion, the findings of this study will enhance our knowledge on the pathological mechanisms involved in atherosclerotic plaque destabilization, and provide potential gene biomarkers for risk stratification of patients with atherosclerotic cardiovascular disease.

Sex Differences in Inflammation During Venous Remodeling of Arteriovenous Fistulae

Vascular disorders frequently have differing clinical presentations among women and men. Sex differences exist in vascular access for hemodialysis; women have reduced rates of arteriovenous fistula (AVF) maturation as well as fistula utilization compared with men. Inflammation is increasingly implicated in both clinical studies and animal models as a potent mechanism driving AVF maturation, especially in vessel dilation and wall thickening, that allows venous remodeling to the fistula environment to support hemodialysis. Sex differences have long been recognized in arterial remodeling and diseases, with men having increased cardiovascular events compared with pre-menopausal women. Many of these arterial diseases are driven by inflammation that is similar to the inflammation during AVF maturation. Improved understanding of sex differences in inflammation during vascular remodeling may suggest sex-specific vascular therapies to improve AVF success.

Regular exercise stimulates endothelium autophagy via IL-1 signaling in ApoE deficient mice

Regular exercise maintains arterial endothelial cell homeostasis and protects the arteries from vascular disease, such as peripheral artery disease and atherosclerosis. Autophagy, which is a cellular process that degrades misfolded or aggregate proteins and damaged organelles, plays an important role in maintaining organ and cellular homeostasis. However, it is unknown whether regular exercise stimulates autophagy in aorta endothelial cells of mice prone to atherosclerosis independently of their circulating lipid profile. Here, we observed that 16 weeks of voluntary exercise reduced high-fat diet-induced atherosclerotic plaque formation in the aortic root of ApoE deficient mice, and that this protection occurred without changes in circulating triglycerides, total cholesterol, and lipoproteins. Immunofluorescence analysis indicated that voluntary exercise increased levels of the autophagy protein LC3 in aortic endothelial cells. Interestingly, human umbilical vein endothelial cells (HUVECs) exposed to serum from voluntarily exercised mice displayed significantly increased LC3-I and LC3-II protein levels. Analysis of circulating cytokines demonstrated that voluntary exercise caused changes directly relevant to IL-1 signaling (ie, decreased interleukin-1 receptor antagonist [IL-1ra] while also increasing IL-1α). HUVECs exposed to IL-1α and IL-1β recombinant protein significantly increased LC3 mRNA expression, LC3-I and LC3-II protein levels, and autophagy flux. Collectively, these results suggest that regular exercise protects arteries from ApoE deficient mice against atherosclerosis at least in part by stimulating endothelial cell autophagy via enhanced IL-1 signaling.

Single-Cell Epigenomics and Functional Fine-Mapping of Atherosclerosis GWAS Loci

Supplemental Digital Content is available in the text.

Genome-wide association studies have identified hundreds of loci associated with coronary artery disease (CAD). Many of these loci are enriched in cisregulatory elements but not linked to cardiometabolic risk factors nor to candidate causal genes, complicating their functional interpretation.

Genetically determined NLRP3 inflammasome activation associates with systemic inflammation and cardiovascular mortality

AIMS

Inflammation plays an important role in cardiovascular disease (CVD) development. The NOD-like receptor protein-3 (NLRP3) inflammasome contributes to the development of atherosclerosis in animal models. Components of the NLRP3 inflammasome pathway such as interleukin-1β can therapeutically be targeted. Associations of genetically determined inflammasome-mediated systemic inflammation with CVD and mortality in humans are unknown.

METHODS AND RESULTS

We explored the association of genetic NLRP3 variants with prevalent CVD and cardiovascular mortality in 538 167 subjects on the individual participant level in an explorative gene-centric approach without performing multiple testing. Functional relevance of single-nucleotide polymorphisms on NLRP3 inflammasome activation has been evaluated in monocyte-enriched peripheral blood mononuclear cells (PBMCs). Genetic analyses identified the highly prevalent (minor allele frequency 39.9%) intronic NLRP3 variant rs10754555 to affect NLRP3 gene expression. rs10754555 carriers showed significantly higher C-reactive protein and serum amyloid A plasma levels. Carriers of the G allele showed higher NLRP3 inflammasome activation in isolated human PBMCs. In carriers of the rs10754555 variant, the prevalence of coronary artery disease was significantly higher as compared to non-carriers with a significant interaction between rs10754555 and age. Importantly, rs10754555 carriers had significantly higher risk for cardiovascular mortality during follow-up. Inflammasome inducers (e.g. urate, triglycerides, apolipoprotein C3) modulated the association between rs10754555 and mortality.

CONCLUSION

The NLRP3 intronic variant rs10754555 is associated with increased systemic inflammation, inflammasome activation, prevalent coronary artery disease, and mortality. This study provides evidence for a substantial role of genetically driven systemic inflammation in CVD and highlights the NLRP3 inflammasome as a therapeutic target.

Virtual Transcriptomics: Noninvasive Phenotyping of Atherosclerosis by Decoding Plaque Biology From Computed Tomography Angiography Imaging

[Figure: see text].