Effect of CD47 Blockade on Vascular Inflammation

Targeting SLC22A5 fosters mitophagy inhibition-mediated macrophage immunity against septic acute kidney injury upon CD47-SIRPα axis blockade

Efferocytosis of apoptotic neutrophils (PMNs) by macrophages is helpful for inflammation resolution and injury repair, but the role of efferocytosis in intrinsic nature of macrophages during septic acute kidney injury (AKI) remains unknown. Here we report that CD47 and signal regulatory protein alpha (SIRPα)-the anti-efferocytotic 'don't eat me' signals-are highly expressed in peripheral blood mononuclear cells (PBMCs) from patients with septic AKI and kidney samples from mice with polymicrobial sepsis and endotoxin shock. Conditional knockout (CKO) of SIRPA in macrophages ameliorates AKI and systemic inflammation response in septic mice, accompanied by an escalation in mitophagy inhibition of macrophages. Ablation of SIRPA transcriptionally downregulates solute carrier family 22 member 5 (SLC22A5) in the lipopolysaccharide (LPS)-stimulated macrophages that efferocytose apoptotic neutrophils (PMNs). Targeting SLC22A5 renders mitophagy inhibition of macrophages in response to LPS stimuli, improves survival and deters development of septic AKI. Our study supports further clinical investigation of CD47-SIRPα signalling in sepsis and proposes that SLC22A5 might be a promising immunotherapeutic target for septic AKI.

Biomimetic Nano-Degrader Based CD47-SIRPα Immune Checkpoint Inhibition Promotes Macrophage Efferocytosis for Cardiac Repair

CD47-SIRPα axis is an immunotherapeutic target in tumor therapy. However, current monoclonal antibody targeting CD47-SIRPα axis is associated with on-target off-tumor and antigen sink effects, which significantly limit its potential clinical application. Herein, a biomimetic nano-degrader is developed to inhibit CD47-SIRPα axis in a site-specific manner through SIRPα degradation, and its efficacy in acute myocardial infarction (AMI) is evaluated. The nano-degrader is constructed by hybridizing liposome with red blood cell (RBC) membrane (RLP), which mimics the CD47 density of senescent RBCs and possesses a natural high-affinity binding capability to SIRPα on macrophages without signaling capacity. RLP would bind with SIRPα and induce its lysosomal degradation through receptor-mediated endocytosis. To enhance its tissue specificity, Ly6G antibody conjugation (aRLP) is applied, enabling its attachment to neutrophils and accumulation within inflammatory sites. In the myocardial infarction model, aRLP accumulated in the infarcted myocardium blocks CD47-SIRPα axis and subsequently promoted the efferocytosis of apoptotic cardiomyocytes by macrophage, improved heart repair. This nano-degrader efficiently degraded SIRPα in lysosomes, providing a new strategy for immunotherapy with great clinical transformation potential.

Hypercholesterolemia exacerbates in-stent restenosis in rabbits: Studies of the mitigating effect of stent surface modification with a CD47-derived peptide

BACKGROUND AND AIMS

Hypercholesterolemia (HC) has previously been shown to augment the restenotic response in animal models and humans. However, the mechanistic aspects of in-stent restenosis (ISR) on a hypercholesterolemic background, including potential augmentation of systemic and local inflammation precipitated by HC, are not completely understood. CD47 is a transmembrane protein known to abort crucial inflammatory pathways. Our studies have examined the interrelation between HC, inflammation, and ISR and investigated the therapeutic potential of stents coated with a CD47-derived peptide (pepCD47) in the hypercholesterolemic rabbit model.

METHODS

PepCD47 was immobilized on metal foils and stents using polybisphosphonate coordination chemistry and pyridyldithio/thiol conjugation. Cytokine expression in buffy coat-derived cells cultured over bare metal (BM) and pepCD47-derivatized foils demonstrated an M2/M1 macrophage shift with pepCD47 coating. HC and normocholesterolemic (NC) rabbit cohorts underwent bilateral implantation of BM and pepCD47 stents (HC) or BM stents only (NC) in the iliac location.

RESULTS

A 40 % inhibition of cell attachment to pepCD47-modified compared to BM surfaces was observed. HC increased neointimal growth at 4 weeks post BM stenting. These untoward outcomes were mitigated in hypercholesterolemic rabbits treated with pepCD47-derivatized stents. Compared to NC animals, inflammatory cytokine immunopositivity and macrophage infiltration of peri-strut areas increased in HC animals and were attenuated in HC rabbits treated with pepCD47 stents.

CONCLUSIONS

Augmented inflammatory responses underlie severe ISR morphology in hypercholesterolemic rabbits. Blockage of initial platelet and leukocyte attachment to stent struts through CD47 functionalization of stents mitigates the pro-restenotic effects of hypercholesterolemia.

Novel Perspectives in Chronic Kidney Disease-Specific Cardiovascular Disease

Chronic kidney disease (CKD) affects > 10% of the global adult population and significantly increases the risk of cardiovascular disease (CVD), which remains the leading cause of death in this population. The development and progression of CVD-compared to the general population-is premature and accelerated, manifesting as coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. CKD and CV disease combine to cause multimorbid cardiorenal syndrome (CRS) due to contributions from shared risk factors, including systolic hypertension, diabetes mellitus, obesity, and dyslipidemia. Additional neurohormonal activation, innate immunity, and inflammation contribute to progressive cardiac and renal deterioration, reflecting the strong bidirectional interaction between these organ systems. A shared molecular pathophysiology-including inflammation, oxidative stress, senescence, and hemodynamic fluctuations characterise all types of CRS. This review highlights the evolving paradigm and recent advances in our understanding of the molecular biology of CRS, outlining the potential for disease-specific therapies and biomarker disease detection.

Association between Immune Checkpoint Inhibitors and Atherosclerotic Cardiovascular Disease Risk: Another Brick in the Wall

In recent years, immune checkpoint inhibitors have significantly changed the field of oncology, emerging as first-line treatment, either alone or in combination with other regimens, for numerous malignancies, improving overall survival and progression-free survival in these patients. However, immune checkpoint inhibitors might also cause severe or fatal immune-related adverse events, including adverse cardiovascular events. Initially, myocarditis was recognized as the main immune checkpoint inhibitor-related cardiac event, but our knowledge of other potential immune-related cardiovascular adverse events continues to broaden. Recently, preclinical and clinical data seem to support an association between immune checkpoint inhibitors and accelerated atherosclerosis as well as atherosclerotic cardiovascular events such as cardiac ischemic disease, stroke, and peripheral artery disease. In this review, by offering a comprehensive overview of the pivotal role of inflammation in atherosclerosis, we focus on the potential molecular pathways underlying the effects of immune checkpoint inhibitors on cardiovascular diseases. Moreover, we provide an overview of therapeutic strategies for cancer patients undergoing immunotherapy to prevent the development of cardiovascular diseases.

Directional Endothelial Communication by Polarized Extracellular Vesicle Release

BACKGROUND

Extracellular vesicles (EVs) contain bioactive cargo including miRNAs and proteins that are released by cells during cell-cell communication. Endothelial cells (ECs) form the innermost lining of all blood vessels, interfacing with cells in the circulation and vascular wall. It is unknown whether ECs release EVs capable of governing recipient cells within these 2 separate compartments. Given their boundary location, we propose ECs use bidirectional release of distinct EV cargo in quiescent (healthy) and activated (atheroprone) states to communicate with cells within the circulation and blood vessel wall.

METHODS

EVs were isolated from primary human aortic ECs (plate and transwell grown; ±IL [interleukin]-1β activation), quantified, visualized, and analyzed by miRNA transcriptomics and proteomics. Apical and basolateral EC-EV release was determined by miRNA transfer, total internal reflection fluorescence and electron microscopy. Vascular reprogramming (RNA sequencing) and functional assays were performed on primary human monocytes or smooth muscle cells±EC-EVs.

RESULTS

Activated ECs increased EV release, with miRNA and protein cargo related to atherosclerosis. EV-treated monocytes and smooth muscle cells revealed activated EC-EV altered pathways that were proinflammatory and atherogenic. ECs released more EVs apically, which increased with activation. Apical and basolateral EV cargo contained distinct transcriptomes and proteomes that were altered by EC activation. Notably, activated basolateral EC-EVs displayed greater changes in the EV secretome, with pathways specific to atherosclerosis. In silico analysis determined compartment-specific cargo released by the apical and basolateral surfaces of ECs can reprogram monocytes and smooth muscle cells, respectively, with functional assays and in vivo imaging supporting this concept.

CONCLUSIONS

Demonstrating that ECs are capable of polarized EV cargo loading and directional EV secretion reveals a novel paradigm for endothelial communication, which may ultimately enhance the design of endothelial-based therapeutics for cardiovascular diseases such as atherosclerosis where ECs are persistently activated.

Macrophage mediators and mechanisms in cardiovascular disease

Macrophages are major players in myocardial infarction (MI) and atherosclerosis, two major cardiovascular diseases (CVD). Atherosclerosis is caused by the buildup of cholesterol-rich lipoproteins in blood vessels, causing inflammation, vascular injury, and plaque formation. Plaque rupture or erosion can cause thrombus formation resulting in inadequate blood flow to the heart muscle and MI. Inflammation, particularly driven by macrophages, plays a central role in both atherosclerosis and MI. Recent integrative approaches of single-cell analysis-based classifications in both murine and human atherosclerosis as well as experimental MI showed overlap in origin, diversity, and function of macrophages in the aorta and the heart. We here discuss differences and communalities between macrophages in the heart and aorta at steady state and in atherosclerosis or upon MI. We focus on markers, mediators, and functional states of macrophage subpopulations. Recent trials testing anti-inflammatory agents show a major benefit in reducing the inflammatory burden of CVD patients, but highlight a necessity for a broader understanding of immune cell ontogeny and heterogeneity in CVD. The novel insights into macrophage biology in CVD represent exciting opportunities for the development of novel treatment strategies against CVD.

Inflammation Resolution in the Cardiovascular System: Arterial Hypertension, Atherosclerosis, and Ischemic Heart Disease

Significance: Chronic inflammation has emerged as a major underlying cause of many prevalent conditions in the Western world, including cardiovascular diseases. Although targeting inflammation has emerged as a promising avenue by which to treat cardiovascular disease, it is also associated with increased risk of infection. Recent Advances: Though previously assumed to be passive, resolution has now been identified as an active process, mediated by unique immunoresolving mediators and mechanisms designed to terminate acute inflammation and promote tissue repair. Recent work has determined that failures of resolution contribute to chronic inflammation and the progression of human disease. Specifically, failure to produce pro-resolving mediators and the impaired clearance of dead cells from inflamed tissue have been identified as major mechanisms by which resolution fails in disease. Critical Issues: Drawing from a rapidly expanding body of experimental and clinical studies, we review here what is known about the role of inflammation resolution in arterial hypertension, atherosclerosis, myocardial infarction, and ischemic heart disease. For each, we discuss the involvement of specialized pro-resolving mediators and pro-reparative cell types, including T regulatory cells, myeloid-derived suppressor cells, and macrophages. Future Directions: Pro-resolving therapies offer the promise of limiting chronic inflammation without impairing host defense. Therefore, it is imperative to better understand the mechanisms underlying resolution to identify therapeutic targets. Antioxid. Redox Signal. 40, 292-316.

Specialized pro-resolving mediators in vascular inflammation and atherosclerotic cardiovascular disease

Timely resolution of the acute inflammatory response (or inflammation resolution) is an active, highly coordinated process that is essential to optimal health. Inflammation resolution is regulated by specific endogenous signalling molecules that function as 'stop signals' to terminate the inflammatory response when it is no longer needed; to actively promote healing, regeneration and tissue repair; and to limit pain. Specialized pro-resolving mediators are a superfamily of signalling molecules that initiate anti-inflammatory and pro-resolving actions. Without an effective and timely resolution response, inflammation can become chronic, a pathological state that is associated with many widely occurring human diseases, including atherosclerotic cardiovascular disease. Uncovering the mechanisms of inflammation resolution failure in cardiovascular diseases and identifying useful biomarkers for non-resolving inflammation are unmet needs. In this Review, we discuss the accumulating evidence that supports the role of non-resolving inflammation in atherosclerosis and the use of specialized pro-resolving mediators as therapeutic tools for the treatment of atherosclerotic cardiovascular disease. We highlight open questions about therapeutic strategies and mechanisms of disease to provide a framework for future studies on the prevention and treatment of atherosclerosis.

Clonal Expansion in Cardiovascular Pathology

Clonal expansion refers to the proliferation and selection of advantageous "clones" that are better suited for survival in a Darwinian manner. In recent years, we have greatly enhanced our understanding of cell clonality in the cardiovascular context. However, our knowledge of the underlying mechanisms behind this clonal selection is still severely limited. There is a transpiring pattern of clonal expansion of smooth muscle cells and endothelial cells-and, in some cases, macrophages-in numerous cardiovascular diseases irrespective of their differing microenvironments. These findings indirectly suggest the possible existence of stem-like vascular cells which are primed to respond during disease. Subsequent clones may undergo further phenotypic changes to adopt either protective or detrimental roles. By investigating these clone-forming vascular cells, we may be able to harness this inherent clonal nature for future therapeutic intervention. This review comprehensively discusses what is currently known about clonal expansion across the cardiovascular field. Comparisons of the clonal nature of vascular cells in atherosclerosis (including clonal hematopoiesis of indeterminate potential), pulmonary hypertension, aneurysm, blood vessel injury, ischemia- and tumor-induced angiogenesis, and cerebral cavernous malformations are evaluated. Finally, we discuss the potential clinical implications of these findings and propose that proper understanding and specific targeting of these clonal cells may provide unique therapeutic options for the treatment of these cardiovascular conditions.

Immunotherapy-Associated Atherosclerosis: A Comprehensive Review of Recent Findings and Implications for Future Research

Purpose of the Review

Even as immune checkpoint inhibitors (ICIs) have transformed the lifespan of many patients, they may also trigger acceleration of long-term cardiovascular disease. Our review aims to examine the current landscape of research on ICI-mediated atherosclerosis and address key questions regarding its pathogenesis and impact on patient management.

Recent Findings

Preclinical mouse models suggest that T cell dysregulation and proatherogenic cytokine production are key contributors to plaque development after checkpoint inhibition. Clinical data also highlight the significant burden of atherosclerotic cardiovascular disease (ASCVD) in patients on immunotherapy, although the value of proactively preventing and treating ASCVD in this population remains an open area of inquiry. Current treatment options include dietary/lifestyle modification and traditional medications to manage hypertension, hyperlipidemia, and diabetes risk factors; no current targeted therapies exist.

Summary

Early identification of high-risk patients is crucial for effective preventive strategies and timely intervention. Future research should focus on refining screening tools, elucidating targetable mechanisms driving ICI atherosclerosis, and evaluating long-term cardiovascular outcomes in cancer survivors who received immunotherapy. Moreover, close collaboration between oncologists and cardiologists is essential to optimize patient outcomes.

The role of CD47 in non-neoplastic diseases

CD47 is a 50 kDa five-spanning membrane receptor that plays a crucial role in multiple cellular processes, including myeloid cell activation, neutrophils transmigration, vascular remodeling, leukocyte adhesion and trans-endothelial migration. Recent studies have revealed that CD47 is a highly expressed anti-phagocytic signal in several types of cancer, and therefore, blocking of CD47 has shown an effective therapeutic potential in cancer immunotherapy. In addition, CD47 has been found to be involved in a complex interplay with microglia and other types of cells, and increasing evidence indicates that CD47 can be targeted as part of immune modulatory strategies for non-neoplastic diseases as well. In this review, we focus on CD47 and its role in non-neoplastic diseases, including neurological disorders, atherosclerosis and autoimmune diseases. In addition, we discuss the major challenges and potential remedies associated with CD47-SIRPα-based immunotherapies.

Role of vascular smooth muscle cell clonality in atherosclerosis

Atherosclerotic cardiovascular disease remains the leading cause of death worldwide. While many cell types contribute to the growing atherosclerotic plaque, the vascular smooth muscle cell (SMC) is a major contributor due in part to its remarkable plasticity and ability to undergo phenotype switching in response to injury. SMCs can migrate into the fibrous cap, presumably stabilizing the plaque, or accumulate within the lesional core, possibly accelerating vascular inflammation. How SMCs expand and react to disease stimuli has been a controversial topic for many decades. While early studies relying on X-chromosome inactivation were inconclusive due to low resolution and sensitivity, recent advances in multi-color lineage tracing models have revitalized the concept that SMCs likely expand in an oligoclonal fashion during atherogenesis. Current efforts are focused on determining whether all SMCs have equal capacity for clonal expansion or if a "stem-like" progenitor cell may exist, and to understand how constituents of the clone decide which phenotype they will ultimately adopt as the disease progresses. Mechanistic studies are also beginning to dissect the processes which confer cells with their overall survival advantage, test whether these properties are attributable to intrinsic features of the expanding clone, and define the role of cross-talk between proliferating SMCs and other plaque constituents such as neighboring macrophages. In this review, we aim to summarize the historical perspectives on SMC clonality, highlight unanswered questions, and identify translational issues which may need to be considered as therapeutics directed against SMC clonality are developed as a novel approach to targeting atherosclerosis.

The role of efferocytosis-fueled macrophage metabolism in the resolution of inflammation

The phagocytosis of dying cells by macrophages, termed efferocytosis, is a tightly regulated process that involves the sensing, binding, engulfment, and digestion of apoptotic cells. Efferocytosis not only prevents tissue necrosis and inflammation caused by secondary necrosis of dying cells, but it also promotes pro-resolving signaling in macrophages, which is essential for tissue resolution and repair following injury or inflammation. An important factor that contributes to this pro-resolving reprogramming is the cargo that is released from apoptotic cells after their engulfment and phagolysosomal digestion by macrophages. The apoptotic cell cargo contains amino acids, nucleotides, fatty acids, and cholesterol that function as metabolites and signaling molecules to bring about this re-programming. Here, we review efferocytosis-induced changes in macrophage metabolism that mediate the pro-resolving functions of macrophages. We also discuss various strategies, challenges, and future perspectives related to drugging efferocytosis-fueled macrophage metabolism as strategy to dampen inflammation and promote resolution in chronic inflammatory diseases.

CD47 blockade enhances phagocytosis of cardiac cell debris by neutrophils

CD47 is a cell surface protein controlling phagocytotic activity of innate immune cells. CD47 blockade was investigated as an immune checkpoint therapy in cancer treatment, enhancing phagocytosis of tumor cells by macrophages. Anti-CD47 treatment also reduced injury size during reperfused acute myocardial infarction (repAMI) by enhancing phagocytotic acitivity of macrophages. Little is known about the impact of CD47 blockade on neutrophils, representing the main portion of early infiltrating immune cells after repAMI. Therefore, we performed 45 min of cardiac ischemia followed by 24 h of reperfusion, observing a decreased cardiac injury size measured by triphenyl tetrazolium chloride (TTC) Evan's blue staining. We were able to detect this effect with an innovative three-dimensional method based on light sheet fluorescence microscopy (LSFM). This further allowed us a simultaneous analysis of neutrophil infiltration, showing an unaltered amount of injury-associated neutrophils with reduced cardiac injury volume from repAMI. This observation suggests modulated phagocytosis of cell debris by neutrophils. Therefore, we performed flow cytometry analysis, revealing an increased phagocytotic activity of neutrophils in vitro. These findings highlight that CD47 blockade also enhances phagocytosis of cardiac cell debris by neutrophils, which might be an additional protective effect of anti-CD47 treatment after repAMI.

Specialized pro-resolving mediators enhance the clearance of dead cells

The failure to resolve inflammation underpins to several prevalent diseases, like atherosclerosis, and so identifying ways to boost resolution is unmet clinical needs. The resolution of inflammation is governed by several factors such as specialized pro-resolving mediators (SPMs) that counter-regulate pro-inflammatory pathways and promote tissue repair without compromising host defense. A major function of nearly all SPMs is to enhance the clearance of dead cells or efferocytosis. As such, phagocytes, such as macrophages, are essential cellular players in the resolution of inflammation because of their ability to rapidly and efficiently clear dead cells. This review highlights the role of SPMs in the clearance of apoptotic and necroptotic cells and offers insights into how targeting efferocytosis may provide new treatments for non-resolving diseases, like atherosclerosis.

Identifying shared transcriptional risk patterns between atherosclerosis and cancer

Cancer and cardiovascular disease (CVD) are the leading causes of death worldwide. Numerous overlapping pathophysiologic mechanisms have been hypothesized to drive the development of both diseases. Further investigation of these common pathways could allow for the identification of mutually detrimental processes and therapeutic targeting to derive mutual benefit. In this study, we intersect transcriptomic datasets correlated with disease severity or patient outcomes for both cancer and atherosclerotic CVD. These analyses confirmed numerous pathways known to underlie both diseases, such as inflammation and hypoxia, but also identified several novel shared pathways. We used these to explore common translational targets by applying the drug prediction software, OCTAD, to identify compounds that simultaneously reverse the gene expression signature for both diseases. These analyses suggest that certain tumor-specific therapeutic approaches may be implemented so that they avoid cardiovascular consequences, and in some cases may even be used to simultaneously target co-prevalent cancer and atherosclerosis.

Risk of Cancer After Diagnosis of Cardiovascular Disease

Background

Cardiovascular disease (CVD) and cancer share several risk factors. Although preclinical models show that various types of CVD can accelerate cancer progression, clinical studies have not determined the impact of atherosclerosis on cancer risk.

Objectives

The objective of this study was to determine whether CVD, especially atherosclerotic CVD, is independently associated with incident cancer.

Methods

Using IBM MarketScan claims data from over 130 million individuals, 27 million cancer-free subjects with a minimum of 36 months of follow-up data were identified. Individuals were stratified by presence or absence of CVD, time-varying analysis with multivariable adjustment for cardiovascular risk factors was performed, and cumulative risk of cancer was calculated. Additional analyses were performed according to CVD type (atherosclerotic vs nonatherosclerotic) and cancer subtype.

Results

Among 27,195,088 individuals, those with CVD were 13% more likely to develop cancer than those without CVD (HR: 1.13; 95% CI: 1.12-1.13). Results were more pronounced for individuals with atherosclerotic CVD (aCVD), who had a higher risk of cancer than those without CVD (HR: 1.20; 95% CI: 1.19-1.21). aCVD also conferred a higher risk of cancer compared with those with nonatherosclerotic CVD (HR: 1.11; 95% CI: 1.11-1.12). Cancer subtype analyses showed specific associations of aCVD with several malignancies, including lung, bladder, liver, colon, and other hematologic cancers.

Conclusions

Individuals with CVD have an increased risk of developing cancer compared with those without CVD. This association may be driven in part by the relationship of atherosclerosis with specific cancer subtypes, which persists after controlling for conventional risk factors.

Endothelial cells secrete small extracellular vesicles bidirectionally containing distinct cargo to uniquely reprogram vascular cells in the circulation and vessel wall

Rationale

Extracellular vesicles (EVs) contain bioactive cargo including microRNAs (miRNAs) and proteins that are released by cells as a form of cell-cell communication. Endothelial cells (ECs) form the innermost lining of all blood vessels and thereby interface with cells in the circulation as well as cells residing in the vascular wall. It is unknown whether ECs have the capacity to release EVs capable of governing recipient cells within two separate compartments, and how this is affected by endothelial activation commonly seen in atheroprone regions.

Objective

Given their boundary location, we propose that ECs utilize bidirectional release of distinct EV cargo in quiescent and activated states to communicate with cells within the circulation and blood vessel wall.

Methods and Results

EVs were isolated from primary human aortic endothelial cells (ECs) (+/-IL-1β activation), quantified, and analysed by miRNA transcriptomics and proteomics. Compared to quiescent ECs, activated ECs increased EV release, with miRNA and protein cargo that were related to atherosclerosis. RNA sequencing of EV-treated monocytes and smooth muscle cells (SMCs) revealed that EVs from activated ECs altered pathways that were pro-inflammatory and atherogenic. Apical and basolateral EV release was assessed using ECs on transwells. ECs released more EVs apically, which increased with activation. Apical and basolateral EV cargo contained distinct transcriptomes and proteomes that were altered by EC activation. Notably, basolateral EC-EVs displayed greater changes in the EV secretome, with pathways specific to atherosclerosis. In silico analysis determined that compartment-specific cargo released by the apical and basolateral surfaces of ECs can reprogram monocytes and SMCs, respectively.

Conclusions

The demonstration that ECs are capable of polarized EV cargo loading and directional EV secretion reveals a novel paradigm for endothelial communication, which may ultimately enhance our ability to design endothelial-based therapeutics for cardiovascular diseases such as atherosclerosis where ECs are persistently activated.

Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities

Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.

Harnessing prostaglandin E2 signaling to ameliorate autoimmunity

The etiology of most autoimmune diseases remains unknown; however, shared among them is a disruption of immunoregulation. Prostaglandin lipid signaling molecules possess context-dependent immunoregulatory properties, making their role in autoimmunity difficult to decipher. For example, prostaglandin E2 (PGE2) can function as an immunosuppressive molecule as well as a proinflammatory mediator in different circumstances, contributing to the expansion and activation of T cell subsets associated with autoimmunity. Recently, PGE2 was shown to play important roles in the resolution and post-resolution phases of inflammation, promoting return to tissue homeostasis. We propose that PGE2 plays both proinflammatory and pro-resolutory roles in the etiology of autoimmunity, and that harnessing this signaling pathway during the resolution phase might help prevent autoimmune attack.

Atherosclerosis With Immune Checkpoint Inhibitor Therapy: Evidence, Diagnosis, and Management: JACC: CardioOncology State-of-the-Art Review

As the clinical applications of immune checkpoint inhibitors (ICIs) expand, our knowledge of the potential adverse effects of these drugs continues to broaden. Emerging evidence supports the association between ICI therapy with accelerated atherosclerosis and atherosclerotic cardiovascular (CV) events. We discuss the biological plausibility and the clinical evidence supporting an effect of inhibition of these immune checkpoints on atherosclerotic CV disease. Further, we provide a perspective on potential diagnostic and pharmacological strategies to reduce atherosclerotic risk in ICI-treated patients. Our understanding of the pathophysiology of ICI-related atherosclerosis is in its early stages. Further research is needed to identify the mechanisms linking ICI therapy to atherosclerosis, leverage the insight that ICI therapy provides into CV biology, and develop robust approaches to manage the expanding cohort of patients who may be at risk for atherosclerotic CV disease.

Cardiovascular complications of immune checkpoint inhibitors for cancer

Over the last decade or so, there has been a paradigm shift in the oncologic care of patients with a range of solid tumour and haematologic malignancies, away from traditional cytotoxic chemotherapy and towards personalized cancer treatments, using both targeted therapy and immunotherapy. This shift has contributed to the remarkable and sustained increase in the number of cancer survivors and the longevity of patients with a cancer diagnosis. This review will focus on the cardiovascular effects of immune checkpoint inhibitors and will present a background on immune checkpoint inhibition for cancer, the epidemiology, potential mechanisms, the potential insights into cardiovascular biology, and a diagnostic and therapeutic approach to potential cases. Our understanding of the cardiovascular effects of immune checkpoint inhibitors needs to improve. However, the evolution necessarily needs to be rapid. Initial observations noted that immune checkpoint inhibitor therapy can lead to a fulminant myocarditis. Recent reports have expanded the effect of immune checkpoint inhibitor therapy on the cardiovascular system to include an increase in cardiac dysfunction without myocarditis, arrhythmias, venous thromboembolic disease, accelerated atherosclerosis, and atherosclerosis-related cardiovascular events. The association between immune checkpoint inhibitor therapy and an increase in these cardiovascular events is not only limited to events occurring within the first few weeks after starting therapy but can also include events that occur months to years after therapy. The latter observation is especially of relevance in those treated with adjuvant or neoadjuvant therapy. There needs to be a shift from recognition of an increase in cardiovascular events to currently approved immune checkpoint inhibitor therapies to understanding the mechanisms that lead to adverse cardiovascular effects, understanding who is at risk, and understanding what we can do about it.

Regulated Necrosis in Atherosclerosis

During atherosclerosis, lipid-rich plaques are formed in large- and medium-sized arteries, which can reduce blood flow to tissues. This situation becomes particularly precarious when a plaque develops an unstable phenotype and becomes prone to rupture. Despite advances in identifying and treating vulnerable plaques, the mortality rate and disability caused by such lesions remains the number one health threat in developed countries. Vulnerable, unstable plaques are characterized by a large necrotic core, implying a prominent role for necrotic cell death in atherosclerosis and plaque destabilization. Necrosis can occur accidentally or can be induced by tightly regulated pathways. Over the past decades, different forms of regulated necrosis, including necroptosis, ferroptosis, pyroptosis, and secondary necrosis, have been identified, and these may play an important role during atherogenesis. In this review, we describe several forms of necrosis that may occur in atherosclerosis and how pharmacological modulation of these pathways can stabilize vulnerable plaques. Moreover, some challenges of targeting necrosis in atherosclerosis such as the presence of multiple death-inducing stimuli in plaques and extensive cross-talk between necrosis pathways are discussed. A better understanding of the role of (regulated) necrosis in atherosclerosis and the mechanisms contributing to plaque destabilization may open doors to novel pharmacological strategies and will enable clinicians to tackle the residual cardiovascular risk that remains in many atherosclerosis patients.

Dynamic changes in chromatin accessibility are associated with the atherogenic transitioning of vascular smooth muscle cells

AIMS

De-differentiation and activation of pro-inflammatory pathways are key transitions vascular smooth muscle cells (SMCs) make during atherogenesis. Here, we explored the upstream regulators of this 'atherogenic transition'.

METHODS AND RESULTS

Genome-wide sequencing studies, including Assay for Transposase-Accessible Chromatin using sequencing and RNA-seq, were performed on cells isolated from both murine SMC-lineage-tracing models of atherosclerosis and human atherosclerotic lesions. At the bulk level, alterations in chromatin accessibility were associated with the atherogenic transitioning of lesional SMCs, especially in relation to genes that govern differentiation status and complement-dependent inflammation. Using computational biology, we observed that a transcription factor previously related to coronary artery disease, Activating transcription factor 3 (ATF3), was predicted to be an upstream regulator of genes altered during the transition. At the single-cell level, our results indicated that ATF3 is a key repressor of SMC transitioning towards the subset of cells that promote vascular inflammation by activating the complement cascade. The expression of ATF3 and complement component C3 was negatively correlated in SMCs from human atherosclerotic lesions, suggesting translational relevance. Phenome-wide association studies indicated that genetic variation that results in reduced expression of ATF3 is correlated with an increased risk for atherosclerosis, and the expression of ATF3 was significantly down-regulated in humans with advanced vascular disease.

CONCLUSION

Our study indicates that the plasticity of atherosclerotic SMCs may in part be explained by dynamic changes in their chromatin architecture, which in turn may contribute to their maladaptive response to inflammation-induced stress.

Tackling inflammation in atherosclerosis: Are we there yet and what lies beyond?

Atherosclerosis is a lipid-driven disease of the artery characterized by chronic non-resolving inflammation. Despite availability of excellent lipid-lowering therapies, atherosclerosis remains the leading cause of disability and death globally. The demonstration that suppressing inflammation prevents the adverse clinical manifestations of atherosclerosis in recent clinical trials has led to heightened interest in anti-inflammatory therapies. In this review, we briefly highlight some key anti-inflammatory and pro-resolution pathways, which could be targeted to modulate pathogenesis and stall atherosclerosis progression. We also highlight key challenges that must be overcome to turn the concept of inflammation targeting therapies into clinical reality for atherosclerotic heart disease.

Pomegranate Peel Extract Decreases Plaque Necrosis and Advanced Atherosclerosis Progression in Apoe -/- Mice

Atherosclerosis is a chronic lipid-driven inflammatory condition of the arteries and is a leading cause of stroke, myocardial infarction, and other peripheral arterial diseases. Plant products rich in polyphenols such as pomegranate juice and peel extract are known to have beneficial effects in suppressing atherogenesis. However, the mechanism of action and its effect on advanced atherosclerosis progression which results in adverse clinical outcomes are not well understood. Herein, we use a standardized hydroethanolic extract of Punica granatum (pomegranate) peel in the Apoe^-/- a murine model of advanced atherosclerosis. It was observed that the pomegranate peel extract fed mice have decreased plaque necrosis and elevated lesional collagen content which was associated with a favorable metabolic profile including lowering of blood glucose, cholesterol, and triglyceride. The decrease in plaque necrosis was linked with increased lesional macrophage efferocytosis efficiency which was associated with enhanced expression of the efferocytosis receptor Mertk. Using in vitro studies, we show that pomegranate peel extract blocks the shedding of Mertk and preserves macrophage efferocytosis efficiency. These data identify a novel mechanism by which pomegranate peel extract promotes the resolution of inflammation in atherosclerosis.

2021 Jeffrey M. Hoeg Award Lecture: Defining the Role of Efferocytosis in Cardiovascular Disease: A Focus on the CD47 (Cluster of Differentiation 47) Axis

A key feature of atherogenesis is the accumulation of diseased and dying cells within the lesional necrotic core. While the burden of intraplaque apoptotic cells may be driven in part by an increase in programmed cell death, mounting evidence suggests that their presence may primarily be dictated by a defect in programmed cell removal, or efferocytosis. In this brief review, we will summarize the evidence suggesting that inflammation-dependent changes within the plaque render target cells inedible and reduce the appetite of lesional phagocytes. We will present the genetic causation studies, which indicate these phenomena promote lesion expansion and plaque vulnerability, and the interventional data which suggest that these processes can be reversed. Particular emphasis is provided related to the antiphagocytic CD47 (cluster of differentiation 47) do not eat me axis, which has emerged as a novel antiatherosclerotic translational target that is predicted to provide benefit independent of traditional cardiovascular risk factors.

CD47 antibody protects mice from doxorubicin-induced myocardial damage by suppressing cardiomyocyte apoptosis

Cluster of differentiation 47 (CD47) is upregulated in mouse models of doxorubicin (Dox)-induced dilated cardiomyopathy (DCM). To explore the role of CD47 in the development of DCM, in the present study, CD47 signaling was blocked by an anti-CD47 neutralizing antibody (aCD47) in mice with Dox-induced DCM. Intraperitoneal (i.p.) administration of 10 mg/kg Dox once a week significantly induced the development of DCM after 4 weeks, which was accompanied by the upregulation of CD47 expression in heart tissues. However, co-administration of Dox with 7 mg/kg aCD47 once a week significantly reduced the severity of DCM, with lower numbers of disordered and broken myofibers, reduced cardiomyocytes and infiltration of macrophages in the heart tissues of treated mice. The beneficial effects were associated with the reduced population of Annexin V⁺7-AAD^- apoptotic cells, and the attenuated formation of interstitial fibrosis and release of lactate dehydrogenase (LDH) in the aCD47-treated mice. In addition, co-administration with aCD47 effectively reduced the expression of Bax, collagen I, interleukin (IL)-6 and tumor necrosis factor (TNF)-α in murine DCM. These results were further supported by an in vitro study, in which aCD47 pre-treatment significantly reduced the Dox-induced early apoptosis of cardiomyocytes and suppressed the expression of Bax, cleaved caspase-1/3 and phosphorylation of p38 MAPK. Therefore, aCD47 attenuated DCM in mice, possibly by suppressing cardiomyocyte early apoptosis and p38 MAPK signaling. CD47 may be a useful therapeutic target in the treatment of DCM.

The Endothelium as a Hub for Cellular Communication in Atherogenesis: Is There Directionality to the Message?

Endothelial cells line every blood vessel and thereby serve as an interface between the blood and the vessel wall. They have critical functions for maintaining homeostasis and orchestrating vascular pathogenesis. Atherosclerosis is a chronic disease where cholesterol and inflammatory cells accumulate in the artery wall below the endothelial layer and ultimately form plaques that can either progress to occlude the lumen or rupture with thromboembolic consequences – common outcomes being myocardial infarction and stroke. Cellular communication lies at the core of this process. In this review, we discuss traditional (e.g., cytokines, chemokines, nitric oxide) and novel (e.g., extracellular vesicles) modes of endothelial communication with other endothelial cells as well as circulating and vessel wall cells, including monocytes, macrophages, neutrophils, vascular smooth muscle cells and other immune cells, in the context of atherosclerosis. More recently, the growing appreciation of endothelial cell plasticity during atherogenesis suggests that communication strategies are not static. Here, emerging data on transcriptomics in cells during the development of atherosclerosis are considered in the context of how this might inform altered cell-cell communication. Given the unique position of the endothelium as a boundary layer that is activated in regions overlying vascular inflammation and atherosclerotic plaque, there is a potential to exploit the unique features of this group of cells to deliver therapeutics that target the cellular crosstalk at the core of atherosclerotic disease. Data are discussed supporting this concept, as well as inherent pitfalls. Finally, we briefly review the literature for other regions of the body (e.g., gut epithelium) where cells similarly exist as a boundary layer but provide discrete messages to each compartment to govern homeostasis and disease. In this light, the potential for endothelial cells to communicate in a directional manner is explored, along with the implications of this concept – from fundamental experimental design to biomarker potential and therapeutic targets.

Emerging Concepts of Vascular Cell Clonal Expansion in Atherosclerosis

Clonal expansion is a process that can drive pathogenesis in human diseases, with atherosclerosis being a prominent example. Despite advances in understanding the etiology of atherosclerosis, clonality studies of vascular cells remain in an early stage. Recently, several paradigm-shifting preclinical studies have identified clonal expansion of progenitor cells in the vasculature in response to atherosclerosis. This review provides an overview of cell clonality in atherosclerotic progression, focusing particularly on smooth muscle cells and macrophages. We discuss key findings from the latest research that give insight into the mechanisms by which clonal expansion of vascular cells contributes to disease pathology. The further probing of these mechanisms will provide innovative directions for future progress in the understanding and therapy of atherosclerosis and its associated cardiovascular diseases.

The pleiotropic benefits of statins include the ability to reduce CD47 and amplify the effect of pro-efferocytic therapies in atherosclerosis

The pleiotropic benefits of statins may result from their impact on vascular inflammation. The molecular process underlying this phenomenon is not fully elucidated. Here, RNA sequencing designed to investigate gene expression patterns following CD47-SIRPα inhibition identifies a link between statins, efferocytosis, and vascular inflammation. In vivo and in vitro studies provide evidence that statins augment programmed cell removal by inhibiting the nuclear translocation of NFκB1 p50 and suppressing the expression of the critical 'don't eat me' molecule, CD47. Statins amplify the phagocytic capacity of macrophages, and thus the anti-atherosclerotic effects of CD47-SIRPα blockade, in an additive manner. Analyses of clinical biobank specimens suggest a similar link between statins and CD47 expression in humans, highlighting the potential translational implications. Taken together, our findings identify efferocytosis and CD47 as pivotal mediators of statin pleiotropy. In turn, statins amplify the anti-atherosclerotic effects of pro-phagocytic therapies independently of any lipid-lowering effect.

Immune Checkpoint Therapies and Atherosclerosis: Mechanisms and Clinical Implications: JACC State-of-the-Art Review

Immune checkpoint inhibitor therapy has revolutionized the treatment of advanced malignancies in recent years. Numerous reports have detailed the myriad of possible adverse inflammatory effects of immune checkpoint therapies, including within the cardiovascular system. However, these reports have been largely limited to myocarditis. The critical role of inflammation and adaptive immunity in atherosclerosis has been well characterized in preclinical studies, and several emerging clinical studies indicate a potential role of immune checkpoint targeting therapies in the development and exacerbation of atherosclerosis. In this review, we provide an overview of the role of T-cell immunity in atherogenesis and describe the molecular effects and clinical associations of both approved and investigational immune checkpoint therapy on atherosclerosis. We also highlight the role of cholesterol metabolism in oncogenesis and discuss the implications of these associations on future treatment and monitoring of atherosclerotic cardiovascular disease in the oncologic population receiving immune checkpoint therapy.

Transcriptional determinants of cancer immunotherapy response and resistance

The host immune response is a potent defense mechanism against cancer development and progression. To survive, cancer cells must develop mechanisms to evade the immune response. Based on this knowledge, a series of new therapies collectively referred to as immunotherapies have been developed and translated to the clinic for treating cancer patients. Although some cancer subtypes have shown strong clinical responses, including curative outcomes in some patients, immunotherapies have not worked as desired for some subtypes and forms of cancers. We provide an overview of the transcriptional mechanisms that drive the response and resistance to immunotherapies. We also discuss possible interventions to enhance the outcomes of immunotherapies by targeting dysregulated transcriptional networks in cancer cells.

Clonal Expansion of Stem/Progenitor Cells in Cancer, Fibrotic Diseases, and Atherosclerosis, and CD47 Protection of Pathogenic Cells

We proposed and demonstrated that myelogenous leukemia has a preleukemic phase. In the premalignant phase, normal hematopoietic stem cells (HSCs) gradually accumulate mutations leading to HSC clonal expansion, resulting in the emergence of leukemic stem cells (LSCs). Here, we show that preleukemic HSCs are the basis of clonal hematopoiesis, as well as late-onset blood diseases (chronic-phase chronic myeloid leukemia, myeloproliferative neoplasms, and myelodysplastic disease). The clones at some point each trigger surface expression of "eat me" signals for macrophages, and in the clones and their LSC progeny, this is countered by upregulation of "don't eat me" signals for macrophages such as CD47,opening the possibility of CD47-based therapies. We include evidence that similar processes result in fibroblast expansion in a variety of fibrotic diseases, and arterial smooth muscle clonal expansion is a basis of atherosclerosis, including upregulation of both "eat me" and "don't eat me" molecules on the pathogenic cells.

Inflammation Resolution: Implications for Atherosclerosis

Resolution is an active and highly coordinated process that occurs in response to inflammation to limit tissue damage and promote repair. When the resolution program fails, inflammation persists. It is now understood that failed resolution is a major underlying cause of many chronic inflammatory diseases. Here, we will review the major failures of resolution in atherosclerosis, including the imbalance of proinflammatory to pro-resolving mediator production, impaired clearance of dead cells, and functional changes in immune cells that favor ongoing inflammation. In addition, we will briefly discuss new concepts that are emerging as possible regulators of resolution and highlight the translational significance for the field.

Loss of myeloid cell-specific SIRPα, but not CD47, attenuates inflammation and suppresses atherosclerosis

AIMS

Inhibitors of the anti-phagocytic CD47-SIRPα immune checkpoint are currently in clinical development for a variety of haematological and solid tumours. Application of immune checkpoint inhibitors to the cardiovascular field is limited by the lack of preclinical studies using genetic models of CD47 and SIRPα inhibition. In this study, we comprehensively analysed the effects of global and cell-specific SIRPα and CD47 deletion on atherosclerosis development.

METHODS AND RESULTS

Here, we show that both SIRPα and CD47 expression are increased in human atherosclerotic arteries and primarily co-localize to CD68+ areas in the plaque region. Hypercholesterolaemic mice homozygous for a Sirpa mutant lacking the signalling cytoplasmic region (Sirpamut/mut) and myeloid cell-specific Sirpa-knockout mice are protected from atherosclerosis. Further, global Cd47-/- mice are protected from atherosclerosis but myeloid cell-specific deletion of Cd47 increased atherosclerosis development. Using a combination of techniques, we show that loss of SIRPα signalling in macrophages stimulates efferocytosis, reduces cholesterol accumulation, promotes lipid efflux, and attenuates oxidized LDL-induced inflammation in vitro and induces M2 macrophage phenotype and inhibits necrotic core formation in the arterial wall in vivo. Conversely, loss of myeloid cell CD47 inhibited efferocytosis, impaired cholesterol efflux, augmented cellular inflammation, stimulated M1 polarization, and failed to decrease necrotic core area in atherosclerotic vessels. Finally, comprehensive blood cell analysis demonstrated lower haemoglobin and erythrocyte levels in Cd47-/- mice compared with wild-type and Sirpamut/mut mice.

CONCLUSION

Taken together, these findings identify SIRPα as a potential target in atherosclerosis and suggest the importance of cell-specific CD47 inhibition as a future therapeutic strategy.

Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment

Atherosclerosis, the chronic accumulation of cholesterol-rich plaque within arteries, is associated with a broad spectrum of cardiovascular diseases including myocardial infarction, aortic aneurysm, peripheral vascular disease, and stroke. Atherosclerotic cardiovascular disease remains a leading cause of mortality in high-income countries and recent years have witnessed a notable increase in prevalence within low- and middle-income regions of the world. Considering this prominent and evolving global burden, there is a need to identify the cellular mechanisms that underlie the pathogenesis of atherosclerosis to discover novel therapeutic targets for preventing or mitigating its clinical sequelae. Despite decades of research, we still do not fully understand the complex cell-cell interactions that drive atherosclerosis, but new investigative approaches are rapidly shedding light on these essential mechanisms. The vascular endothelium resides at the interface of systemic circulation and the underlying vessel wall and plays an essential role in governing pathophysiological processes during atherogenesis. In this review, we present emerging evidence that implicates the activated endothelium as a driver of atherosclerosis by directing site-specificity of plaque formation and by promoting plaque development through intracellular processes, which regulate endothelial cell proliferation and turnover, metabolism, permeability, and plasticity. Moreover, we highlight novel mechanisms of intercellular communication by which endothelial cells modulate the activity of key vascular cell populations involved in atherogenesis, and discuss how endothelial cells contribute to resolution biology - a process that is dysregulated in advanced plaques. Finally, we describe important future directions for preclinical atherosclerosis research, including epigenetic and targeted therapies, to limit the progression of atherosclerosis in at-risk or affected patients.

Cancer stem cells: advances in biology and clinical translation-a Keystone Symposia report

The test for the cancer stem cell (CSC) hypothesis is to find a target expressed on all, and only CSCs in a patient tumor, then eliminate all cells with that target that eliminates the cancer. That test has not yet been achieved, but CSC diagnostics and targets found on CSCs and some other cells have resulted in a few clinically relevant therapies. However, it has become apparent that eliminating the subset of tumor cells characterized by self-renewal properties is essential for long-term tumor control. CSCs are able to regenerate and initiate tumor growth, recapitulating the heterogeneity present in the tumor before treatment. As great progress has been made in identifying and elucidating the biology of CSCs as well as their interactions with the tumor microenvironment, the time seems ripe for novel therapeutic strategies that target CSCs to find clinical applicability. On May 19-21, 2021, researchers in cancer stem cells met virtually for the Keystone eSymposium "Cancer Stem Cells: Advances in Biology and Clinical Translation" to discuss recent advances in the understanding of CSCs as well as clinical efforts to target these populations.

CD47 antibody blockade suppresses microglia-dependent phagocytosis and monocyte transition to macrophages, impairing recovery in EAE

Experimental autoimmune encephalomyelitis (EAE) is a well-characterized animal model of multiple sclerosis. During the early phase of EAE, infiltrating monocytes and monocyte-derived macrophages contribute to T cell recruitment, especially CD4⁺ T cells, into the CNS, resulting in neuronal demyelination; however, in later stages, they promote remyelination and recovery by removal of myelin debris by phagocytosis. Signal regulatory protein α and CD47 are abundantly expressed in the CNS, and deletion of either molecule is protective in myelin oligodendrocyte glycoprotein–induced EAE because of failed effector T cell expansion and trafficking. Here we report that treatment with the function blocking CD47 Ab Miap410 substantially reduced the infiltration of pathogenic immune cells but impaired recovery from paresis. The underlying mechanism was by blocking the emergence of CD11c^hiMHCII^hi microglia at peak disease that expressed receptors for phagocytosis, scavenging, and lipid catabolism, which mediated clearance of myelin debris and the transition of monocytes to macrophages in the CNS. In the recovery phase of EAE, Miap410 Ab–treated mice had worsening paresis with sustained inflammation and limited remyelination as compared with control Ab–treated mice. In summary, Ab blockade of CD47 impaired resolution of CNS inflammation, thus worsening EAE.

Inflammation, Infection and Venous Thromboembolism

The association between inflammation, infection, and venous thrombosis has long been recognized; yet, only in the last decades have we begun to understand the mechanisms through which the immune and coagulation systems interact and reciprocally regulate one another. These interconnected networks mount an effective response to injury and pathogen invasion, but if unregulated can result in pathological thrombosis and organ damage. Neutrophils, monocytes, and platelets interact with each other and the endothelium in host defense and also play critical roles in the formation of venous thromboembolism. This knowledge has advanced our understanding of both human physiology and pathophysiology, as well as identified mechanisms of anticoagulant resistance and novel therapeutic targets for the prevention and treatment of thrombosis. In this review, we discuss the contributions of inflammation and infection to venous thromboembolism.

The Mechanism of Stimulating and Mobilizing the Immune System Enhancing the Anti-Tumor Immunity

Cancer immunotherapy is a kind of therapy that can control and eliminate tumors by restarting and maintaining the tumor-immune cycle and restoring the body's normal anti-tumor immune response. Although immunotherapy has great potential, it is currently only applicable to patients with certain types of tumors, such as melanoma, lung cancer, and cancer with high mutation load and microsatellite instability, and even in these types of tumors, immunotherapy is not effective for all patients. In order to enhance the effectiveness of tumor immunotherapy, this article reviews the research progress of tumor microenvironment immunotherapy, and studies the mechanism of stimulating and mobilizing immune system to enhance anti-tumor immunity. In this review, we focused on immunotherapy against tumor microenvironment (TME) and discussed the important research progress. TME is the environment for the survival and development of tumor cells, which is composed of cell components and non-cell components; immunotherapy for TME by stimulating or mobilizing the immune system of the body, enhancing the anti-tumor immunity. The checkpoint inhibitors can effectively block the inhibitory immunoregulation, indirectly strengthen the anti-tumor immune response and improve the effect of immunotherapy. We also found the checkpoint inhibitors have brought great changes to the treatment model of advanced tumors, but the clinical treatment results show great individual differences. Based on the close attention to the future development trend of immunotherapy, this study summarized the latest progress of immunotherapy and pointed out a new direction. To study the mechanism of stimulating and mobilizing the immune system to enhance anti-tumor immunity can provide new opportunities for cancer treatment, expand the clinical application scope and effective population of cancer immunotherapy, and improve the survival rate of cancer patients.

Dead cell and debris clearance in the atherosclerotic plaque: Mechanisms and therapeutic opportunities to promote inflammation resolution

Phagocytic clearance of dead cells and debris is critical for inflammation resolution and maintenance of tissue homeostasis. Consequently, defective clearance of dead cells and debris is associated with initiation and exacerbation of several autoimmune disorders and chronic inflammatory diseases such as atherosclerosis. The progressive loss of dead cell clearance capacity within the atherosclerotic plaque leads to accumulation of necrotic cells, chronic non-resolving inflammation, and expansion of the necrotic core, which triggers atherosclerotic plaque rupture and clinical manifestation of acute thrombotic cardiovascular adverse events. In this review, we describe the fundamental molecular and cellular mechanisms of dead cell clearance and how it goes awry in atherosclerosis. Finally, we highlight novel therapeutic strategies that enhance dead cell and debris clearance within the atherosclerotic plaque to promote inflammation resolution and atherosclerotic plaque stabilization.

Antibody-Based Therapeutics for Atherosclerosis and Cardiovascular Diseases

Cardiovascular disease is the leading cause of death worldwide, and its prevalence is increasing due to the aging of societies. Atherosclerosis, a type of chronic inflammatory disease that occurs in arteries, is considered to be the main cause of cardiovascular diseases such as ischemic heart disease or stroke. In addition, the inflammatory response caused by atherosclerosis confers a significant effect on chronic inflammatory diseases such as psoriasis and rheumatic arthritis. Here, we review the mechanism of action of the main causes of atherosclerosis such as plasma LDL level and inflammation; furthermore, we review the recent findings on the preclinical and clinical effects of antibodies that reduce the LDL level and those that neutralize the cytokines involved in inflammation. The apolipoprotein B autoantibody and anti-PCSK9 antibody reduced the level of LDL and plaques in animal studies, but failed to significantly reduce carotid inflammation plaques in clinical trials. The monoclonal antibodies against PCSK9 (alirocumab, evolocumab), which are used as a treatment for hyperlipidemia, lowered cholesterol levels and the incidence of cardiovascular diseases. Antibodies that neutralize inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-17, and IL-12/23) have shown promising but contradictory results and thus warrant further research.

Putting the brakes on phagocytosis: "don't-eat-me" signaling in physiology and disease

Timely removal of dying or pathogenic cells by phagocytes is essential to maintaining host homeostasis. Phagocytes execute the clearance process with high fidelity while sparing healthy neighboring cells, and this process is at least partially regulated by the balance of "eat-me" and "don't-eat-me" signals expressed on the surface of host cells. Upon contact, eat-me signals activate "pro-phagocytic" receptors expressed on the phagocyte membrane and signal to promote phagocytosis. Conversely, don't-eat-me signals engage "anti-phagocytic" receptors to suppress phagocytosis. We review the current knowledge of don't-eat-me signaling in normal physiology and disease contexts where aberrant don't-eat-me signaling contributes to pathology.

Mechanisms and clinical manifestations of cardiovascular toxicities associated with immune checkpoint inhibitors

Immunotherapies have greatly expanded the armamentarium of cancer-directed therapies in the past decade, allowing the immune system to recognize and fight cancer. Immune checkpoint inhibitors (ICIs), in particular, have revolutionized cancer treatment and have demonstrated survival benefit in numerous types of cancer. These monoclonal antibodies increase anti-cancer immunity by blocking down-regulators of adaptive immunity, including cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and its ligand (PD-L1), resulting in anti-tumor activity. As ICIs increase immune system activation, they can cause a wide range of inflammatory side effects, termed immune-released adverse events. Though these toxicities can affect nearly any organ, the most fatal toxicity is myocarditis. Here, we discuss the diverse spectrum of cardiovascular toxicities associated with ICI use. In addition, we provide insight and future directions on mechanisms and treatments for immune-related adverse events (irAEs) involving the myocardium, pericardium, vasculature, and conduction system.