Efferocytosis in atherosclerosis

Phenotyping atherosclerotic plaque and perivascular adipose tissue: signalling pathways and clinical biomarkers in atherosclerosis

Computed tomography coronary angiography provides a non-invasive evaluation of coronary artery disease that includes phenotyping of atherosclerotic plaques and the surrounding perivascular adipose tissue (PVAT). Image analysis techniques have been developed to quantify atherosclerotic plaque burden and morphology as well as the associated PVAT attenuation, and emerging radiomic approaches can add further contextual information. PVAT attenuation might provide a novel measure of vascular health that could be indicative of the pathogenetic processes implicated in atherosclerosis such as inflammation, fibrosis or increased vascularity. Bidirectional signalling between the coronary artery and adjacent PVAT has been hypothesized to contribute to coronary artery disease progression and provide a potential novel measure of the risk of future cardiovascular events. However, despite the development of more advanced radiomic and artificial intelligence-based algorithms, studies involving large datasets suggest that the measurement of PVAT attenuation contributes only modest additional predictive discrimination to standard cardiovascular risk scores. In this Review, we explore the pathobiology of coronary atherosclerotic plaques and PVAT, describe their phenotyping with computed tomography coronary angiography, and discuss potential future applications in clinical risk prediction and patient management.

Apolipoprotein B-containing lipoproteins in atherogenesis

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

Nontyphoidal salmonellosis is associated with an increased risk of stroke: Insights from multinational real-world data

BACKGROUND

Stroke is a significant cause of morbidity and mortality worldwide, contributing substantially to the global burden of disease. In low- and middle-income countries, stroke tends to occur at younger ages, with infection being one of the notable contributing factors. Previous studies have explored the impact of nontyphoidal Salmonella (NTS) on vascular and blood-related diseases, with animal experiments confirming related mechanisms. This study aims to investigate the association between NTS and cerebrovascular diseases (CVDs), with a focus on identifying specific patient populations more susceptible to stroke due to infection.

METHODS

This retrospective cohort study utilized the TriNetX database, including 4708 patients infected with NTS compared with a healthy population, with disease risk tracked over 6 months, 1 year, and lifelong periods. The primary outcome was CVDs (ICD-10-CM: I60-I69), while secondary outcomes examined hemorrhagic stroke (ICD-10-CM: I60-I62) and ischemic stroke (ICD-10-CM: I63). Subgroup analyses were conducted based on gender and age at index, with sensitivity analysis performed by comparing hospitalized patients, utilizing different databases, and evaluating the specificity of the NTS-CVD association by examining patients with a higher risk of acute myocardial infarction (AMI).

RESULTS

The lifelong hazard ratios (HRs) for cerebrovascular diseases (CVD), hemorrhagic stroke, and ischemic stroke following NTS infection were 1.606 (95% confidence interval (CI), 1.410-1.830), 1.866 (95% CI, 1.304-2.669), and 1.717 (95% CI, 1.385-2.130), respectively. A significant increase in the risk of hemorrhagic stroke was observed in the short term and mid-term, with HRs of 3.345 (95% CI, 1.091-10.259) and 2.816 (95% CI, 1.184-6.699), respectively. Subgroup analyses indicated statistically significant associations with the primary outcomes across all age groups. Males demonstrated a higher risk of hemorrhagic stroke, with an HR of 1.891 (95% CI, 1.142-3.310), whereas females exhibited a stronger association with ischemic stroke, with an HR of 1.592 (95% CI, 1.189-2.132). These associations remained significant among hospitalized patients, while no significant relationship was observed between NTS infection and AMI. The findings of this study were reproducible in a US-based database.

CONCLUSION

There is a significant association between NTS and CVD, with a particularly important impact on the occurrence of stroke in younger populations, especially regarding the elevated risk of hemorrhagic stroke.

Haematometabolism rewiring in atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular diseases are the most frequent cause of death worldwide. The clinical complications of atherosclerosis are closely linked to the haematopoietic and immune systems, which maintain homeostatic functions and vital processes in the body. The nodes linking metabolism and inflammation are receiving increasing attention because they are inextricably linked to inflammatory manifestations of non-communicable diseases, including atherosclerosis. Although metabolism and inflammation are essential to survival and involve all tissues, we still know little about how these processes influence each other. In an effort to understand these mechanisms, in this Review we explore whether and how potent cardiovascular risk factors and metabolic modifiers of atherosclerosis influence the molecular and cellular machinery of 'haematometabolism' (metabolic-dependent haematopoietic stem cell skewing) and 'efferotabolism' (metabolic-dependent efferocyte reprogramming). These changes might ultimately propagate a quantitative and qualitative drift of the macrophage supply chain and affect the clinical manifestations of atherosclerosis. Refining our understanding of the different metabolic requirements of these processes could open the possibility of developing therapeutics targeting haematometabolism that, in conjunction with improved dietary habits, help rebalance and promote efficient haematopoiesis and efferocytosis and decrease the risk of atherosclerosis complications.

The molecular mechanism by which CTSB degrades FPN to disrupt macrophage iron homeostasis and promote the progression of atherosclerosis

The incidence of atherosclerosis (AS) remains high, and iron-dependent cell death (termed ferroptosis) is thought to play a key role in the progression of AS. Studies have shown that cathepsin B (CTSB) is an important regulatory molecule in atherosclerosis. However, how CTSB regulates AS progression has not been reported, and whether it is related to ferroptosis is poorly studied. In the present study, we observed a significant upregulation of CTSB expression in two AS models, ApoE knockout mice and SD rats given a HFD. According to our findings, CTSB can promote development of the AS plaque region, while inhibition of CTSB showed a reduction of AS lesion area and lipid deposition. Single-cell transcriptome analysis of AS tissue from humans revealed that CTSB is primarily expressed in macrophages. Oxidized low-density lipoprotein (ox-LDL) significantly enhanced macrophage CTSB expression, and induced ferroptosis in vitro. Mechanistically, Ferroportin (FPN) is the binding target of CTSB. CTSB can negatively regulate the protein level of FPN and promote its degradation, which further leads to ferroptosis of macrophages. We confirmed that ferroptosis in macrophages could be effectively inhibited by knockdown or pharmacological inhibition of CTSB, which in turn slowed the progression of AS. In conclusion, our study suggests that CTSB disrupts iron homeostasis in macrophages by degrading FPN and induces ferroptosis, thereby exacerbating the development of AS. Targeting CTSB may become an important potential strategy for the treatment of AS.

Elucidating the role of KLRD1 in coronary atherosclerosis: harnessing bioinformatics and machine learning to advance understanding

BACKGROUND

Atherosclerosis (AS) is increasingly recognized as a chronic inflammatory disease that significantly compromises vascular health and serves as a major contributor to cardiovascular diseases. KLRD1 is a gene that encodes a protein involved in the immune system, specifically in the function of natural killer (NK) cells.

METHODS

KLRD1 was identified as a focal point through an integrative analysis of DEGs across multiple datasets (GSE43292 and GSE9820) from the GEO database, aligned with immune-related gene sets from the ImmPort database. Advanced analytical tools, including Lasso regression and SVM-RFE, were employed to refine our gene selection. We further applied GSEA and GSVA to these gene sets, revealing significant enrichment in immune-related pathways. The relationship between KLRD1 expression and immune processes was examined using CIBERSORT and ESTIMATE algorithms to assess tumor microenvironment characteristics, suggesting increased immune cell infiltration associated with higher KLRD1 expression. Validation of these findings was conducted using data from the GSE9820 dataset.

RESULTS

Among 340 DEGs linked with KLRD1, 13 were identified as hub genes through LASSO and SVM-RFE analyses. Functional assays highlighted KLRD1's role in mononuclear cell differentiation, regulation of cell-cell adhesion, regulation of T cell activation. A Lollipop was created to display the expression patterns of Correlation Coefficient. T cells CD8, Plasma cells, Dendritic cells activated, T cells CD4 memory resting, T cells CD4 memory activated, T cells gamma delta.

CONCLUSIONS

This research elucidates the complex relationship between KLRD1 and AS, underscoring its potential as a novel biomarker for diagnosing and monitoring the disease.

A dual-targeting bio-liposomes nanodrug repair endothelial cell dysfunction and restore macrophage cholesterol flow homeostasis to treat early atherosclerosis

Hyperhomocysteinemia (HHy) can lead to vascular endothelial cell dysfunction, progressive inflammation and lipid metabolism disorder, which finally result in the onset and development of atherosclerosis, a major contributor to cardiovascular diseases. Given the complexity of pathological process, treatments based on a single target often showed limited therapeutic efficacy against AS. Thus, developing nanodrug for enhanced multi-targets therapy is promising. In this study, we constructed a dual-targeting nanodrug (HA-ML@ES NPs) co-loaded with Shikonin (SKN) and Evolocumab (Evol). In vitro results showed that HA-ML@ES NPs could simultaneously target dysfunctional endothelial cell and inflammatory macrophage through the interaction between HA and CD44. In vivo assay indicated that HA-ML@ES NPs with long circulation and plaque accumulation efficiently attenuate endothelial cell dysfunction by inhibiting glycolysis and restore cholesterol flow homeostasis in macrophage by reprogramming macrophage phenotype, which finally attenuated the development of atherosclerosis. Collectively, these results present a highly promising dual-cell therapeutic approach based on HA-ML@ES NPs for the management of early atherosclerosis.

Wearable ring sensor for monitoring biomarkers of atherosclerosis in sweat

Atherosclerosis-induced cardiovascular diseases are a leading cause of disability and mortality worldwide. Currently, clinical diagnosis of atherosclerosis relies on analysis and assessment by large medical equipment and specialized professionals, involving invasive testing, which limits early detection and prognosis of atherosclerosis. Herein, this work develops a flexible wearable ring sensor for non-invasive real-time in situ monitoring of biomarkers associated with atherosclerosis. The device integrates electrochemical biosensing and microfluidic technology, utilizing screen-printing to create high-precision multi-channel electrodes. It can be worn on fingers to detect sweat flow rate and biomarkers including C-reactive protein (CRP), cholesterol, and potassium ions (K+), with the aim of improving disease management efficiency and enhancing patient experience. The synthesized ZIF-67@AuNPs was used as the signal amplification layer of the adapter sensor. The resulting sensor exhibites sensitive and linear responses within the concentration ranges of 0-100 ng mL-1 for CRP, 0-120 μM for cholesterol, and 10-6-1 M for K+. Further tests on specificity, reproducibility, and stability of the sensor confirm its potential for practical applications. In this work, the wearable ring sensor achieves accurate detection of atherosclerosis biomarkers in sweat samples, providing a new technological approach for non-invasive real-time monitoring that has the potential to contribute to early disease warning and personalized management.

Atractylenolide I Inhibits Nicotine-Induced Macrophage Pyroptosis and Alleviates Atherogenesis by Suppressing the TLR4/ROS/TXNIP/NLRP3 Pathway

Background/Objectives: Studies have shown that Atractylenolide I (AT-I) can exert anti-inflammatory and anti-oxidative effects, protecting against the development of various kinds of cardiovascular diseases. However, whether AT-I prevents nicotine-induced atherogenesis is unknown. This study was designed to explore the effects of AT-I on nicotine-induced macrophage pyroptosis and the progression of atherosclerosis. Methods: RT-qPCR and Western blot were used to detect the mRNA and protein levels of TXNIP and pyroptosis-related factors in THP-1-derived macrophages. ELISA was used to detect the secretion of pro-inflammatory cytokines. Hoechst/PI double-staining assay was used to assess plasma membrane integrity. The ROS assay kit, LDH release assay kit, and caspase-1 activity assay kit were used to detect ROS production, LDH release, and caspase-1 activity. Oil Red O, HE, and Masson staining were used to evaluate lipid accumulation, lesion size, and plaque stability in HFD-fed apoE-/- mice. Results: AT-I treatment significantly decreased pyroptosis-related factors expression, disrupted plasma membrane integrity, and down-regulated pro-inflammatory cytokines secretion, thereby inhibiting nicotine-induced pyroptosis of THP-1-derived macrophages. In addition, AT-I decreased ROS production and the expression of TLR4 and TXNIP. Lentivirus overexpression of TLR4 or TXNIP, or pre-treatment with ROS agonist, mainly reversed the anti-pyroptotic effects of AT-I in nicotine-treated THP-1-derived macrophages. Additionally, administering AT-I to HFD-fed apoE-/- mice markedly decreased nicotine-induced up-regulation of pyroptosis-related proteins in the aortas. Enzymatic methods and ELISA assay suggested that AT-I improved dyslipidemia and inflammation in vivo. Oil Red O, HE, and Masson staining showed that AT-I alleviated lipid accumulation, decreased plaque size, and increased plaque stability. Conclusions: Taken together, AT-I can be regarded as a potential phytomedicine that protects against macrophage pyroptosis and atherosclerosis triggered by nicotine.

Specialized pro-resolving mediators in neutrophil apoptosis regulation: unlocking novel therapeutic potential in kidney diseases

Kidney diseases represent a diverse group of disorders with pathogenic mechanisms involving multiple pathological processes, including inflammation, immunity, and cell death. Neutrophils, as primary effector cells in inflammatory immune responses, participate in defending against renal infection and injury by releasing reactive oxygen species, proteases, and cytokines. However, persistent neutrophil activation is considered a crucial driver of kidney disease progression. Neutrophil apoptosis represents a critical turning point between inflammatory progression and resolution. Specialized pro-resolving mediators (SPMs) are endogenous anti-inflammatory mediators that play a critical role in resolving inflammation. They not only induce neutrophil programmed cell death and promote macrophage-mediated efferocytosis of apoptotic cells but also inhibit neutrophil infiltration and degranulation, ultimately facilitating the restoration of inflammatory microenvironment and tissue homeostasis. This review concentrates on elucidating the mechanisms by which SPMs regulate neutrophil apoptosis and systematically demonstrates their potential as novel therapeutic targets in kidney diseases.

Huoxue Tongluo tablet enhances atherosclerosis efferocytosis by promoting the differentiation of Trem2+ macrophages via PPARγ signaling pathway

BACKGROUND

Atherosclerosis (AS) serves as the primary pathological basis for various cardiovascular and cerebrovascular diseases. Impaired efferocytosis by macrophages within AS plaques exacerbates lipid metabolism disorders and inflammatory responses. Huoxue Tongluo Tablet (HXTL), a traditional Chinese medicine formula, has shown efficacy in treating AS and modulating macrophage function. However, its underlying mechanisms remain unclear. It is hypothesized that HXTL ameliorates AS by enhancing macrophage efferocytosis.

PURPOSE

To assess the efficacy and mechanisms of HXTL in treating AS at the single-cell level.

METHODS

Ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) was used to analyze the constituents of HXTL. HXTL was administered to ApoE⁻/⁻ mice maintained on a high-fat diet. The progression of AS was evaluated by measuring atherosclerotic plaque area, necrotic core formation, collagen depletion, lipid accumulation, lipid profiles, pro-inflammatory mediators, and oxidative stress markers. Transcriptomic analysis was performed to explore the mechanisms underlying the therapeutic effects of HXTL on AS. Efferocytosis-related marker expression was evaluated using immunohistochemistry and quantitative PCR (qPCR), and the efferocytosis index was determined by the co-localization of apoptotic cells and macrophages. Efferocytosis inhibition was induced using Cytochalasin D. Single-cell sequencing was utilized to investigate alterations in Trem2⁺ macrophages following HXTL treatment. Trem2 expression was accessed by immunohistochemistry and qPCR, while flow cytometry and immunofluorescence staining confirmed the changes in Trem2⁺ macrophages. Bioinformatic analyses were conducted to investigate the mechanism through which HXTL enhances efferocytosis by regulating Trem2⁺ macrophage subsets. Western blotting and qPCR were used to assess the expression levels of PPARγ signaling, and the regulatory role of PPARγ signaling in macrophage subpopulation generation and efferocytosis function was accessed using GW9662.

RESULTS

UPLC-MS/MS analysis identified 99 major components in HXTL. In vivo, medium and high doses of HXTL significantly reduced atherosclerotic plaque area, improved lipid profiles, decreased pro-inflammatory mediators and reactive oxygen species (ROS), and enhanced the efferocytosis function. Inhibition of efferocytosis reversed these beneficial effects. Single-cell sequencing and in vivo validation revealed that HXTL upregulated Trem2⁺ macrophages and efferocytosis-related genes. Bioinformatics and in vivo experiments demonstrated that HXTL activated PPARγ signaling, and inhibition of PPARγ signaling negated the pro-efferocytosis effects and the upregulation of Trem2⁺ macrophage upregulation induced by HXTL.

CONCLUSIONS

HXTL activates the PPARγ pathway, upregulates Trem2⁺ macrophages, and enhances macrophage efferocytosis, thereby ameliorating AS. This study is the first to demonstrate the regulatory effects of HXTL on macrophage subpopulations and its pro-efferocytosis activity.

Targeted drug delivery systems for atherosclerosis

Atherosclerosis is a complex cardiovascular disease driven by multiple factors, including aging, inflammation, oxidative stress, and plaque rupture. The progression of this disease is often covert, emphasizing the need for early biomarkers and effective intervention measures. In recent years, advancements in therapeutic strategies have highlighted the potential of targeting specific processes in atherosclerosis, such as plaque localization, macrophage activity, and key enzymes. Based on this, this review discusses the potential role of targeted drugs in the treatment of atherosclerosis. It also focuses on their clinical efficacy in anti-atherosclerosis treatment and their ability to provide more precise therapeutic approaches. The findings underscore that future research can concentrate on exploring newer drug delivery systems and biomarkers to further refine clinical treatment strategies and enhance the long-term dynamic management of atherosclerosis.

Tea Polysaccharide Ameliorates Atherosclerosis by Inhibiting Insulin Resistance-Mediated Hepatic VLDL Overproduction

Hepatic VLDL overproduction, tightly modulated by insulin signaling, plays a pivotal role in the progression of atherosclerosis (AS). The present study aimed to investigate whether inhibition of hepatic VLDL overproduction is a novel therapeutic strategy for the homogeneous tea polysaccharide (TPS3A) to ameliorate AS under insulin resistance (IR) conditions and the potential molecular basis involved. Results showed that TPS3A supplementation effectively alleviated systemic IR and delayed atherosclerotic plaque progression in HFD-exposed ApoE-/- mice. Additionally, TPS3A markedly down-regulated the expression of TG synthesis markers (SREBP-1, ACC1, and FAS) and apoB lipidation markers (apoB, apoCIII, and MTP), while up-regulating the expression of apoB degradation maker (sortilin) and VLDL clearance maker (LDLR), thereby inhibiting VLDL overproduction in insulin-resistant ApoE-/- mice and HepG2 cells. The IRS-mediated PI3K-AKT-mTORC1/FoxO1 insulin signaling cascades are central pathways regulating VLDL production. We found that TPS3A significantly abolished insulin-induced activation of PI3K, AKT, mTORC1, and nuclear FoxO1 in vivo and in vitro. Moreover, the suppression effects of TPS3A on VLDL overproduction were synergistically strengthened by inhibitors targeting PI3K (Wortmannin), AKT (GSK690693), mTORC1 (Rapamycin), and FoxO1 (AS1842856). Overall, TPS3A holds promise in ameliorating AS by inhibiting hepatic VLDL overproduction through the IRS-mediated PI3K-AKT-mTORC1/FoxO1 insulin signaling pathways.

Anti-Inflammatory Lipid Mediators from Polyunsaturated Fatty Acids: Insights into their Role in Atherosclerosis Microenvironments

PURPOSE OF REVIEW

Inflammation has become a major residual risk factor for atherosclerotic cardiovascular disease (ASCVD). Certain lipid mediators, known as specialized proresolving mediators (SPMs), are mainly derived from polyunsaturated fatty acids (PUFAs) and can promote inflammation resolution while maintaining host autoimmunity. This review investigates the synthesis and ligand action pathways of these lipid mediators, as well as their regulatory mechanisms in the microenvironment of atherosclerotic plaques. Furthermore, it explores their clinical therapeutic potential, aiming to offer new insights into novel anti-inflammatory drug targets for the treatment of ASCVD.

RECENT FINDINGS

Reduced levels of SPMs are associated with the progression of atherosclerosis. SPMs inhibit inflammatory responses in the plaque microenvironment by limiting immune cell infiltration, reducing oxidative stress, and promoting the clearance of apoptotic cells, all of which contribute to plaque stabilization. Tyrosine-protein kinase Mer (MerTK), TRIF-related adaptor molecule (TRAM), and high mobility group box 1 (HMGB1) play crucial roles in the modulation of SPM production. Clinical use of ω-3 PUFAs has been shown to reduce the incidence of fatal cardiovascular events. Furthermore, aspirin not only initiates the synthesis of specific SPMs but also extends their activity within the body. The enhanced production of SPMs promotes inflammation resolution in the plaque microenvironment without inducing immunosuppression. This characteristic highlights MerTK, TRAM, and HMGB1 as potential targets for the development of anti-inflammatory drugs. Investigating targets and compounds that enhance the production of SPMs presents a promising strategy for developing future anti-inflammatory agents.

The antipsychotic drug thiothixene stimulates macrophages to clear pathogenic cells by inducing arginase 1 and continual efferocytosis

Stimulating efferocytosis, the phagocytic removal of apoptotic cells by macrophages, has been proposed as a method to eliminate dying or dead cells that accumulate and contribute to diseases such as cancer, atherosclerosis, and infection. Toxicity related to the off-target clearance of healthy tissue has led to the premature termination of multiple clinical programs for proefferocytic therapies. To identify potential proefferocytic therapies with established risk profiles, we screened ~3000 US Food and Drug Administration (FDA)-approved drugs and other well-characterized compounds for their capacity to stimulate efferocytosis. We found that the antipsychotic drug thiothixene stimulated efferocytosis of apoptotic and lipid-laden cells by mouse and human macrophages and enhanced the continual efferocytosis of apoptotic cells. Consistent with thiothixene's suppressive effects on dopaminergic signaling, dopamine potently inhibited efferocytosis in a manner that was only partially reversed by thiothixene. The prophagocytic effects of thiothixene in mouse macrophages depended on increased expression of the gene encoding the retinol-binding protein receptor Stra6L, which, in turn, promoted the production of the continual efferocytosis stimulator arginase 1. Our findings demonstrate that dopamine inhibits efferocytosis in macrophages and identify thiothixene, a generic, FDA-approved antipsychotic drug that has been in use for more than 50 years, as a promising candidate for promoting continual efferocytosis and the removal of diseased tissue.

Palmitic acid alters enhancers/super-enhancers near inflammatory and efferocytosis-associated genes in human monocytes

Free fatty acids like palmitic acid (PA) are elevated in obesity and diabetes and dysregulate monocyte and macrophage functions, contributing to enhanced inflammation in these cardiometabolic diseases. Epigenetic mechanisms regulating enhancer functions play key roles in inflammatory gene expression, but their role in PA-induced monocyte/macrophage dysfunction is unknown. We found that PA treatment altered the epigenetic landscape of enhancers and super-enhancers (SEs) in human monocytes. Integration with RNA-seq data revealed that PA-induced enhancers/SEs correlated with PA-increased expression of inflammatory and immune response genes, while PA-inhibited enhancers correlated with downregulation of phagocytosis and efferocytosis genes. These genes were similarly regulated in macrophages from mouse models of diabetes and accelerated atherosclerosis, human atherosclerosis, and infectious agents. PA-regulated enhancers/SEs harbored SNPs associated with diabetes, obesity, and body mass index indicating disease relevance. We verified increased chromatin interactions between PA-regulated enhancers/SEs and inflammatory gene promoters and reduced interactions at efferocytosis genes. PA-induced gene expression was reduced by inhibitors of BRD4, and NF-κB. PA treatment inhibited phagocytosis and efferocytosis in human macrophages. Together, our findings demonstrate that PA-induced enhancer dynamics at key monocyte/macrophage enhancers/SEs regulate inflammatory and immune genes and responses. Targeting these PA-regulated epigenetic changes could provide novel therapeutic opportunities for cardiometabolic disorders.

Machine Learning-Based Immuno-Inflammatory Index Integrating Clinical Characteristics for Predicting Coronary Artery Plaque Rupture

BACKGROUND

Coronary artery plaque rupture (PR) is closely associated with immune-inflammatory responses. The systemic inflammatory index (SII) and the systemic inflammatory response index (SIRI) have shown potential in predicting the occurrence of PR.

OBJECTIVE

This study aims to establish a machine learning (ML) model that integrates baseline patient characteristics, SII, and SIRI to predict PR. The goal is to identify high-risk PR patients before intravascular imaging examinations.

METHODS

We included 337 patients with acute coronary syndrome who underwent emergency percutaneous coronary intervention and coronary optical coherence tomography (OCT) at the Affiliated Hospital of Zunyi Medical University, China, from May 2023 to October 2023. PR was determined by OCT images. Through manual feature selection, nine features, including SII and SIRI, were included, and an ML model was built using the XGBoost algorithm. Model performance was evaluated using receiver operating characteristic curves and calibration curves. SHAP values were used to assess the contribution of each feature to the model.

RESULTS

The ML model demonstrated a higher area under the curve value (AUC = 0.81) compared to using SII or SIRI alone for prediction. The ML model also showed good calibration. SHAP values revealed that the top three features in the ML model were SII, LDL-C, and SIRI.

CONCLUSION

The immuno-inflammatory index, which integrates comprehensive clinical characteristics, can predict the occurrence of PR. However, large-scale, multicenter studies are needed to confirm the generalizability of the predictive model.

Down-regulation of ATP8B2 in Foam Cells Inhibits Autophagic Flux and ox-LDL Degradation in Atherosclerosis

Our study aims to screen and explore the potential molecular mechanisms of atherosclerosis using a comprehensive research approach combining bioinformatics analysis and molecular biology experiments. Bioinformatics analyses were conducted to screen for key genes with significantly differential expression in atherosclerosis. Subsequently, macrophages and foam cells induced from THP-1 cells were utilized to validate the function of these key genes through siRNA knockdown. Molecular biology experiments encompassed reverse transcription polymerase chain reaction (RT-PCR), Western Blotting, immunofluorescence staining, and JC-1 probe detection of mitochondrial membrane potential. ATP8B2, encoding a P4-ATPase, was significantly downregulated in both plaque tissues and circulating macrophages of atherosclerosis patients. This enzyme influences membrane fusion and other dynamic processes by affecting the asymmetric distribution of phospholipids within the bilayer. Knockdown of ATP8B2 expression significantly inhibited autophagic flux in macrophages, manifested by abnormal accumulation of LC3-II and p62 protein levels. Furthermore, downregulation of ATP8B2 expression significantly inhibited the degradation of oxidized low-density lipoprotein (ox-LDL) by macrophages. Simultaneously, reduced ATP8B2 expression led to decreased mitochondrial membrane potential and mitochondrial dysfunction. Our study unveils for the first time the crucial role of ATP8B2 in atherosclerosis, particularly in maintaining autophagic flux, promoting ox-LDL degradation, and sustaining mitochondrial homeostasis.

SIRPα modulates microglial efferocytosis and neuroinflammation following experimental subarachnoid hemorrhage via the SHP1/STAT6 axis

Subarachnoid hemorrhage induces extensive neuronal cell death, leading to the release of damage-associated molecular patterns (DAMPs). These DAMPs, along with hemoglobin and cell corpses, trigger localized inflammation. Signal regulatory protein alpha (SIRPα) plays a crucial role in efferocytosis by acting as a "don't eat-me" signal, modulating inflammation and tissue homeostasis. However, the precise function and regulatory mechanisms of SIRPα in efferocytosis remain unclear. Proteomic analysis of cerebrospinal fluid (CSF) reveals that SIRPα levels are significantly elevated in the CSF of SAH patients and correlate with clinical outcomes. In vivo and in vitro studies show that microglial knockdown of SIRPα promotes efferocytosis and attenuates neuroinflammation following SAH. SIRPα inhibits efferocytosis by recruiting and phosphorylating SHP1 and SHP2 through phosphorylation of four tyrosine residues in its cytoplasmic domain, with SHP1 playing a particularly critical role. Mutation of these tyrosine residues to non-phosphorylatable alanine residues enhances efferocytosis and reduces neuroinflammation in vitro. RNA-seq analysis suggests that this mutation upregulates the expression of "eat-me" signals, MerTK and CD36, and identifies STAT6 as a key transcription factor involved in this process. In conclusion, SIRPα plays a central role in regulating microglia efferocytosis and neuroinflammation after SAH via the SHP1/STAT6 axis. Targeting this pathway may provide a promising therapeutic approach for SAH.

The various roles of TREM2 in cardiovascular disease

Triggering receptor expressed on myeloid cells-2 (TREM2) is a transmembrane immune receptor that is expressed mainly on macrophages. As a pathology-induced immune signaling hub, TREM2 senses tissue damage and activates immune remodeling in response. Previous studies have predominantly focused on the TREM2 signaling pathway in Alzheimer's disease, metabolic syndrome, and cancer. Recent research has indicated that TREM2 signaling is also activated in various cardiovascular diseases. In this review, we summarize the current understanding and the unanswered questions regarding the role of TREM2 signaling in mediating the metabolism and function of macrophages in atherosclerosis and various models of heart failure. In the context of atherosclerosis, TREM2 signaling promotes foam cell formation and is crucial for maintaining macrophage survival and plaque stability through efferocytosis and cholesterol efflux. Recent studies on myocardial infarction, sepsis-induced cardiomyopathy, and hypertensive heart failure also implicated the protective role of TREM2 signaling in cardiac macrophages through efferocytosis and paracrine functions. Additionally, we discuss the clinical significance of elevated soluble TREM2 (sTREM2) in cardiovascular disease and propose potential therapies targeting TREM2. The overall aim of this review is to highlight the various roles of TREM2 in cardiovascular diseases and to provide a framework for therapeutic strategies targeting TREM2.

NT5E (CD73) as a prognostic biomarker and therapeutic target associated with immune infiltration in lung adenocarcinoma

Lung adenocarcinoma (LUAD), the most common type of lung cancer, is a leading cause of cancer-related mortality. NT5E, an ecto-5'-nucleotidase enzyme, has been implicated in cancer progression, particularly in efferocytosis. Despite its potential involvement, the prognostic significance of NT5E and relationship with immune cell infiltration in LUAD have not been extensively explored. In this study, we performed a comprehensive analysis to elucidate the expression patterns of NT5E and its prognostic implications in LUAD using data from diverse public databases. Multiple computational algorithms, including CIBERSORT, ESTIMATE, and xCell, were employed to assess the correlation between NT5E expression and immune cell infiltration. We found that NT5E was significantly overexpressed at both the mRNA and protein levels in LUAD tissues. Elevated NT5E expression was significantly linked to multiple clinicopathological factors, including metastasis and pathological stage, and served as a strong predictor of poor prognosis in LUAD patients. Gene Set Enrichment Analysis (GSEA) indicated that NT5E plays a crucial role in regulating immune responses, as evidenced by differential gene expression associated with NT5E levels. A strong positive correlation was observed between NT5E expression and the presence of immune cells, including dendritic cells, macrophages, and CD4+ T cells, as well as the expression of various immune cell markers, suggesting that NT5E may influence the prognosis of LUAD patients by regulating immune cell infiltration. Additionally, drug sensitivity analysis highlights the potential of selumetinib and PD318088, both MEK1/2 inhibitors, to target NT5E in LUAD treatment, suggesting their use as single agents or in combination with other therapies. Collectively, these findings establish NT5E as a promising prognostic biomarker and therapeutic target in LUAD, particularly in the context of immune cell infiltration.

Lysosome Functions in Atherosclerosis: A Potential Therapeutic Target

Lysosomes in mammalian cells are recognized as key digestive organelles, containing a variety of hydrolytic enzymes that enable the processing of both endogenous and exogenous substrates. These organelles digest various macromolecules and recycle them through the autophagy-lysosomal system. Recent research has expanded our understanding of lysosomes, identifying them not only as centers of degradation but also as crucial regulators of nutrient sensing, immunity, secretion, and other vital cellular functions. The lysosomal pathway plays a significant role in vascular regulation and is implicated in diseases such as atherosclerosis. During atherosclerotic plaque formation, macrophages initially engulf large quantities of lipoproteins, triggering pathogenic responses that include lysosomal dysfunction, foam cell formation, and subsequent atherosclerosis development. Lysosomal dysfunction, along with the inefficient degradation of apoptotic cells and the accumulation of modified low-density lipoproteins, negatively impacts atherosclerotic lesion progression. Recent studies have highlighted that lysosomal dysfunction contributes critically to atherosclerosis in a cell- and stage-specific manner. In this review, we discuss the mechanisms of lysosomal biogenesis and its regulatory role in atherosclerotic lesions. Based on these lysosomal functions, we propose that targeting lysosomes could offer a novel therapeutic approach for atherosclerosis, shedding light on the connection between lysosomal dysfunction and disease progression while offering new insights into potential anti-atherosclerotic strategies.

Smooth muscle cell-specific CD47 deletion suppresses atherosclerosis

BACKGROUND

Recent smooth muscle cell (SMC)-lineage tracing and single-cell RNA sequencing (scRNA-seq) experiments revealed a significant role of SMC-derived cells in atherosclerosis development. Further, thrombospondin-1 (TSP1), a matricellular protein, and activation of its receptor cluster of differentiation (CD) 47 have been linked with atherosclerosis. However, the role of vascular SMC TSP1-CD47 signaling in regulating VSMC phenotype and atherogenesis remains unknown.

METHODS

We investigated the role of SMC CD47 activation by TSP1 in regulating VSMC phenotype and atherosclerosis development using various in vitro cell-based assays, molecular biological techniques, immunohistological approaches, reanalysis of publicly available scRNA-seq data, and cell-specific knockout mice.

RESULTS

We observed elevated TSP1 expression in human atherosclerotic vascular tissues and VSMCs. TSP1-treated VSMCs exhibited decreased expression of contractile SMC markers (ACTA2, CNN1, and TAGLN) and increased proliferation. Additional experiments and reanalysis of the scRNA-seq dataset showed CD47 as the major TSP1 receptor in VSMCs, with its expression increased in SMC-derived modulated cells of murine atherosclerotic arteries. Knockdown of CD47 gene in human VSMCs upregulated expression of contractile SMC markers and abrogated TSP1's effects on these genes. SMC-specific Cd47 deletion in mice suppressed atherosclerotic lesion formation, reduced macrophage accumulation, and decreased necrotic area. However, no significant differences were observed in weight gain, liver and adipose tissue mass, plasma total cholesterol, and fasting blood glucose between control and SMC-restricted Cd47-deficient mice. Further experiments demonstrated increased efferocytosis of apoptotic CD47-silenced VSMCs by macrophages.

CONCLUSIONS

These findings suggest that CD47 plays a crucial role in regulating VSMC phenotype, and SMC-specific-Cd47 deletion suppresses atherosclerosis.

NEW AND NOTEWORTHY

VSMC phenotypic switching contributes to atherosclerosis development. The present study reports the novel observations that Cd47 levels are upregulated in phenotypically modulated SMCs within atherosclerotic arteries and targeted deletion of Cd47 specifically in SMCs attenuates atherosclerosis. Mechanistic in vitro investigations further showed that TSP1-CD47 signaling regulates VSMC phenotype. Therefore, targeting SMC CD47 represents a promising therapeutic target to suppress atherogenesis.

A Disintegrin and Metalloproteinase 17 Disrupts Bovine Macrophage MER Proto-Oncogene Tyrosine Kinase Integrity to Impede Apoptotic Cell Clearance and Promote Inflammation in Clinical Mastitis

In clinical mastitis of dairy cows, the abnormal accumulation of apoptotic cells (ACs) and subsequent secondary necrosis and inflammation pose significant concerns, with macrophage-mediated efferocytosis, crucial for ACs clearance, remaining unexplored in this context. In nonruminants, MER proto-oncogene tyrosine kinase (MERTK) receptors are essential for efferocytosis and A Disintegrin and Metalloproteinase 17 (ADAM17) is thought to play a role in regulating MERTK integrity. This study aimed to delineate the in situ role of efferocytosis in clinical mastitis, with a particular focus on the interaction between MERTK and ADAM17 in bovine macrophages. In mastitic mammary tissue, a significant accumulation of ACs was observed, along with active macrophage efferocytosis. Western blotting analysis revealed elevated expressions of MERTK and ADAM17, and immunofluorescence confirmed that MERTK is predominantly localized within CD163+ macrophages. Additionally, elevated levels of soluble MERTK (sol-MER) in serum indicated impaired integrity and functionality of MERTK. In vitro experiments with the bovine macrophage cell line Bo-mac cells selectively phagocytosed apoptotic MAC-T cells, a process associated with increased MERTK phosphorylation and an anti-inflammatory phenotype. The activation of ADAM17 by Phorbol 12-myristate 13-acetate (PMA) induced sol-Mer release and impaired efferocytosis, with these effects reversed by the ADAM17 inhibitor TAPI-1. Bo-mac efferocytosis was influenced by the presence and activation of MERTK. Silencing MERTK interrupted efferocytosis, a phenomenon also observed with the inhibition of MERTK phosphorylation by UNC2025, which concurrently suppressed anti-inflammatory cytokine production. These findings suggest that targeting the MERTK-ADAM17 axis could enhance inflammatory resolution, providing a novel therapeutic strategy for dairy cattle health management.

The multifaceted anti-atherosclerotic properties of herbal flavonoids: A comprehensive review

Atherosclerosis (AS) is a major etiological factor underpinning a spectrum of cardiovascular diseases, leading to cerebral infarction, coronary artery disease, and peripheral vascular disease. The chronic progression of AS, spanning from initial plaque formation to the occurrence of acute cardiovascular events, underscores the complexity of AS and the challenges it presents in terms of treatment. Currently, the clinical management of AS relies predominantly on statins and proprotein convertase subtilisin/kexin type 9 inhibitors, which primarily aim to reduce low-density lipoprotein levels and have demonstrated some therapeutic efficacy. Nevertheless, due to their potential side effects, there is a pressing need to actively investigate alternative treatment approaches. Researches on natural compounds derived from herbal medicines, such as flavonoids, hold significant promise in combating AS by regulating lipid metabolism, reducing oxidative stress and inflammation, inhibiting the proliferation of vascular smooth muscle cells, modulating autophagy and additional pathways. Various targets participate in these physiological processes, encompassing acyl-CoA: cholesterol acyltransferase (ACAT), ATP citrate lyase (ACLY), nuclear factor erythroid 2-related factor 2 (Nrf2), krüppel-like factor 2 (KLF2), NOD-like receptor protein 3 (NLRP3), transcription factor EB (TFEB) and so on. This comprehensive review endeavors to synthesize and analyse the most recent findings on herbal flavonoids, shedding light on their anti-atherosclerotic potential and the underlying protective mechanisms and related-targets, which might pave the way for the development of novel drug candidates or the optimization of flavonoid-based therapies.

Chronic inflammation and vascular cell plasticity in atherosclerosis

Vascular smooth muscle cells, endothelial cells and macrophages undergo phenotypic conversions throughout atherosclerosis progression, both as a consequence of chronic inflammation and as subsequent drivers of it. The inflammatory hypothesis of atherosclerosis has been catapulted to the forefront of cardiovascular research as clinical trials have shown that anti-inflammatory therapy reduces adverse cardiovascular events. However, no current therapies have been specifically designed to target the phenotype of plaque cells. Fate mapping has revealed that plaque cells convert to detrimental and beneficial cell phenotypes during atherosclerosis, with cumulative evidence highlighting that vascular cell plasticity is intimately linked with plaque inflammation, ultimately impacting lesion stability. Here we review vascular cell plasticity during atherosclerosis in the context of the chronic inflammatory plaque microenvironment. We highlight the need to better understand how plaque cells behave during therapeutic intervention. We then propose modulating plaque cell phenotype as an unexplored therapeutic paradigm in the clinical setting.

Functions of TAM Receptors and Ligands Protein S and Gas6 in Atherosclerosis and Cardiovascular Disease

Atherosclerosis and cardiovascular disease are associated with high morbidity and mortality in industrialized nations. The Tyro3, Axl, and Mer (TAM) family of receptor tyrosine kinases is involved in the amplification or resolution of atherosclerosis pathology and other cardiovascular pathology. The ligands of these receptors, Protein S (PS) and growth arrest specific protein 6 (Gas6), are essential for TAM receptor functions in the amplification and resolution of atherosclerosis. The Axl-Gas6 interaction has various effects on cardiovascular disease. Mer and PS dampen inflammation, thereby protecting against atherosclerosis progression. Tyro3, the least studied TAM receptor in cardiovascular disease, appears to protect against fibrosis in post-myocardial infarction injury. Ultimately, PS, Gas6, and TAM receptors present an exciting avenue of potential therapeutic targets against inflammation associated with atherosclerosis and cardiovascular disease.

Efferocytosis: the resolution of inflammation in cardiovascular and cerebrovascular disease

Cardiovascular and cerebrovascular diseases have surpassed cancer as significant global health challenges, which mainly include atherosclerosis, myocardial infarction, hemorrhagic stroke and ischemia stroke. The inflammatory response immediately following these diseases profoundly impacts patient prognosis and recovery. Efficient resolution of inflammation is crucial not only for halting the inflammatory process but also for restoring tissue homeostasis. Efferocytosis, the phagocytic clearance of dying cells by phagocytes, especially microglia and macrophages, plays a critical role in this resolution process. Upon tissue injury, phagocytes are recruited to the site of damage where they engulf and clear dying cells through efferocytosis. Efferocytosis suppresses the secretion of pro-inflammatory cytokines, stimulates the production of anti-inflammatory cytokines, modulates the phenotype of microglia and macrophages, accelerates the resolution of inflammation, and promotes tissue repair. It involves three main stages: recognition, engulfment, and degradation of dying cells. Optimal removal of apoptotic cargo by phagocytes requires finely tuned machinery and associated modifications. Key molecules in efferocytosis, such as 'Find-me signals', 'Eat-me signals', and 'Don't eat-me signals', have been shown to enhance efferocytosis following cardiovascular and cerebrovascular diseases. Moreover, various additional molecules, pathways, and mitochondrial metabolic processes have been identified to enhance prognosis and outcomes via efferocytosis in diverse experimental models. Impaired efferocytosis can lead to inflammation-associated pathologies and prolonged recovery periods. Therefore, this review consolidates current understanding of efferocytosis mechanisms and its application in cardiovascular and cerebrovascular diseases, proposing future research directions.

Mechanistic insights into the regression of atherosclerotic plaques

Atherosclerosis is a major contributor to cardiovascular diseases and mortality globally. The progression of atherosclerotic disease results in the expansion of plaques and the development of necrotic cores. Subsequent plaque rupture can lead to thrombosis, occluding blood vessels, and end-organ ischemia with consequential ischemic injury. Atherosclerotic plaques are formed by the accumulation of lipid particles overloaded in the subendothelial layer of blood vessels. Abnormally elevated blood lipid levels and impaired endothelial function are the initial factors leading to atherosclerosis. The atherosclerosis research has never been interrupted, and the previous view was that the pathogenesis of atherosclerosis is an irreversible and chronic process. However, recent studies have found that the progression of atherosclerosis can be halted when patients' blood lipid levels are reversed to normal or lower. A large number of studies indicates that it can inhibit the progression of atherosclerosis lesions and promote the regression of atherosclerotic plaques and necrotic cores by lowering blood lipid levels, improving the repair ability of vascular endothelial cells, promoting the reverse cholesterol transport in plaque foam cells and enhancing the ability of macrophages to phagocytize and clear the necrotic core of plaque. This article reviews the progress of research on the mechanism of atherosclerotic plaque regression. Our goal is to provide guidance for developing better therapeutic approaches to atherosclerosis by reviewing and analyzing the latest scientific findings.

Huanglian Jiedu Decoction enhances the stability of atherosclerotic plaques through SLC2A1-mediated efferocytosis

BACKGROUND

Atherosclerotic (AS) plaques require a dense necrotic core and a robust fibrous cap to maintain stability. While previous studies have indicated that the traditional Chinese medicine Huang Lian Jie Du Decoction (HLJDD) possesses the capability to stabilize AS plaques, the underlying mechanisms remain obscure. This study aims to delve deeper into the potential mechanisms by which HLJDD improves AS through an integrated research strategy.

METHODS

Leveraging an AS model in ApoE-/- mice exposed to a high-fat diet (HFD), we scrutinized the therapeutic effects of HLJDD using microscopic observations, oil red O staining, HE staining and Masson staining. Employing comprehensive techniques of network pharmacology, bioinformatics, and molecular docking, we elucidated the mechanism by which HLJDD stabilizes AS plaques. In vitro experiments, utilizing ox-LDL-induced macrophages and apoptotic vascular smooth muscle cells (VSMCs), assessed the impact of HLJDD on efferocytosis and the role of SLC2A1.

RESULTS

In vivo experiments showcased the efficacy of HLJDD in reducing the quantity of aortic plaques, diminishing lipid deposition, and enhancing plaque stability in AS mice. Employing network pharmacology and machine learning, we pinpointed SLC2A1 as a crucial regulatory target. Molecular docking further validated the binding of HLJDD components with SLC2A1. The experiments demonstrated a dose-dependent upregulation in SLC2A1 expression by HLJDD, amplifying efferocytosis. Importantly, this effect was reversed by the SLC2A1 inhibitor STF-31, highlighting the pivotal role of SLC2A1 as a target.

CONCLUSION

The HLJDD can modulate macrophage efferocytosis by enhancing the expression levels of SLC2A1, thereby improving the stability of atherosclerotic plaques.

Activatable fluorescent probes for atherosclerosis theranostics

The onset of atherosclerosis (AS) is insidious, and early stage patients have atypical clinical symptoms. After being diagnosed in late stage, it is often prone to sudden and fatal cardiovascular events. Therefore, it is highly desirable to develop precise and efficient diagnosis and therapy strategies of AS. Benefiting from high signal-to-noise ratio, low detection limit, high specificity and sensitivity, a series of activatable fluorescent probes based on atherosclerotic microenvironment have emerged for identification and treatment of AS. In this review, we focus on the atherosclerotic microenvironment and briefly summarize the correlation between the structural transformation and fluorescence signal changes of mono-/double-activatable fluorescent probes upon biomarkers stimulation. Moreover, their cutting-edge progress for AS theranostics is described. Finally, the outlook for activatable theranostic probes based on atherosclerotic microenvironment is discussed to aim at promoting innovative research in imaging-guided precise AS therapy.

Role of Antibodies and Their Specificities in Atherosclerotic Cardiovascular Disease

Atherosclerosis is a lipid-driven chronic inflammatory disease that is modulated by innate and adaptive immunity including humoral immunity. Importantly, antibody alterations achieved by genetic means or active and passive immunization strategies in preclinical studies can improve or aggravate atherosclerosis. Additionally, a wide range of epidemiological data demonstrate not only an association between the total levels of different antibody isotypes but also levels of antibodies targeting specific antigens with atherosclerotic cardiovascular disease. Here, we discuss the potential role of atherogenic dyslipidemia on the antibody repertoire and review potential antibody-mediated effector mechanisms involved in atherosclerosis development highlighting the major atherosclerosis-associated antigens that trigger antibody responses.

Pro-efferocytic nanotherapies reduce vascular inflammation without inducing anemia in a large animal model of atherosclerosis

Atherosclerosis is an inflammatory disorder responsible for cardiovascular disease. Reactivation of efferocytosis, the phagocytic removal of cells by macrophages, has emerged as a translational target for atherosclerosis. Systemic blockade of the key 'don't-eat-me' molecule, CD47, triggers the engulfment of apoptotic vascular tissue and potently reduces plaque burden. However, it also induces red blood cell clearance, leading to anemia. To overcome this, we previously developed a macrophage-specific nanotherapy loaded with a chemical inhibitor that promotes efferocytosis. Because it was found to be safe and effective in murine studies, we aimed to advance our nanoparticle into a porcine model of atherosclerosis. Here, we demonstrate that production can be scaled without impairing nanoparticle function. At an early stage of disease, we find our nanotherapy reduces apoptotic cell accumulation and inflammation in the atherosclerotic lesion. Notably, this therapy does not induce anemia, highlighting the translational potential of targeted macrophage checkpoint inhibitors.

Insights from Murine Studies on the Site Specificity of Atherosclerosis

Atherosclerosis is an inflammatory reaction that develops at specific regions within the artery wall and at specific sites of the arterial tree over a varying time frame in response to a variety of risk factors. The mechanisms that account for the interaction of systemic factors and atherosclerosis-susceptible regions of the arterial tree to mediate this site-specific development of atherosclerosis are not clear. The dynamics of blood flow has a major influence on where in the arterial tree atherosclerosis develops, priming the site for interactions with atherosclerotic risk factors and inducing cellular and molecular participants in atherogenesis. But how this accounts for lesion development at various locations along the vascular tree across differing time frames still requires additional study. Currently, murine models are favored for the experimental study of atherogenesis and provide the most insight into the mechanisms that may contribute to the development of atherosclerosis. Based largely on these studies, in this review, we discuss the role of hemodynamic shear stress, SR-B1, and other factors that may contribute to the site-specific development of atherosclerosis.