Ccr5 But Not Ccr1 Deficiency Reduces Development of Diet-Induced Atherosclerosis in Mice

Y-box binding protein 1: A critical target for understanding and treating cardiovascular disease

Cardiovascular diseases (CVDs) remain a significant public health burden, characterized by escalating morbidity and mortality rates and demanding novel therapeutic approaches. Cold shock protein Y-box binding protein 1 (YB-1), a highly conserved RNA/DNA-binding protein, has emerged as a pivotal regulator in various pathophysiological processes, including CVDs. YB-1 exerts pleiotropic functions by modulating gene transcription, pre-mRNA splicing, mRNA translation, and stability. The expression and function of YB-1 are intricately regulated by its subcellular localization, post-translational modifications, upstream regulatory signals. YB-1 plays a multifaceted role in CVDs, influencing inflammation, oxidative stress, cell proliferation, apoptosis, phenotypic switching of smooth muscle cells, and mitochondrial dysfunction. However, the regulation of YB-1 expression and function in CVDs is complex and context-dependent, exhibiting divergent effects even in the same disease across different cell types or at disease stages. This review comprehensively explores the structure, regulation, and functional significance of YB-1 in CVDs. We delve into the transcriptional and translational control mechanisms of YB-1, as well as its post-translational modifications. Furthermore, we elucidate the upstream signaling pathways that influence YB-1 expression, with a particular emphasis on non-coding RNAs and specific upstream molecules. Finally, we systematically examine the role of YB-1 in CVDs, summarizing its expression patterns, regulatory mechanisms, and therapeutic potential as a promising target for novel therapeutic interventions. By providing a comprehensive overview of YB-1's involvement in CVDs, this review aims to stimulate further research and facilitate the development of targeted therapies to improve cardiovascular health.

Autoimmune mechanisms and inflammation in obesity-associated type 2 diabetes, atherosclerosis, and non-alcoholic fatty liver disease

Obesity, characterized by the excessive accumulation of white adipose tissue, is a significant global health burden and a major risk factor for a range of diseases, including malignancies and metabolic disorders. Individuals with high visceral fat content are particularly susceptible to severe complications such as type 2 diabetes, cardiovascular diseases, and liver disorders. However, the pathogenesis of obesity-related metabolic diseases extends beyond simple adiposity. Chronic obesity triggers a prolonged inflammatory response, which leads to tissue fibrosis and sustained organ damage, contributing to multi-organ dysfunction. This review explores the autoimmune mechanisms and inflammatory pathways underlying obesity-induced type 2 diabetes, atherosclerosis, and non-alcoholic fatty liver disease, with an emphasis on their interrelated pathophysiology and the potential for therapeutic interventions.

Serum chemokines combined with multi-modal imaging to evaluate atherosclerotic plaque stability in patients undergoing carotid endarterectomy

Background

Although imaging tools are crucial in identifying features of atherosclerotic plaque, there remains a lack of consensus on the use of serological markers for assessing high-risk plaques.

Methods

Patients diagnosed with CAS who met the criteria for CEA were categorized as the operation group, while those without CAS were designated as the control group. Multi-modal imaging was conducted pre- and post-CEA to evaluate plaque features, such as the volume of calcification and LRNC, intra-plaque hemorrhage, and the degree of carotid stenosis. Serum chemokine levels were measured in both groups before CEA and on the 7th day post-surgery. Morphological features of carotid artery specimens were assessed using H&E and IHC (CD68 and α-SMA) staining to evaluate plaque stability.

Results

No significant differences in the degree of CAS between the operation and control groups. Among the operation group, 26 out of 52 patients were identified as vulnerable plaques. The volume of LRNC was significantly higher in vulnerable plaque, whereas the volume of calcification was significantly lower in vulnerable plaque compared to stable plaque confirmed by multi-modal imaging. Vulnerable plaque exhibited a thin fibrous cap covered an LRNC, intra-plaque hemorrhage, and macrophage infiltration. Stable plaque were characterized by small lipid cores covered by a thick fibrous cap, with minimal macrophage infiltration. Chemokine levels were significantly elevated in CAS patients compared to controls, and decreased significantly on the 7th day post-CEA. In patients with vulnerable plaque, lower levels of CX3CL1, CXCL12, CCL19, and CCL21, but higher levels of CCL2 and CCL5, were observed compared to patients with stable plaque. Correlation analysis further indicated that CX3CL1 and CXCL12 levels were positively associated with calcification volume. While CCL2 and CCL5 levels were positively associated, and CCL19 and CCL21 negatively associated, with LRNC volume. Multivariate analysis suggested that CXCL12 was an independent protective factor and LRNC volume as an independent risk factor for plaque vulnerability. The combination with multi-modal imaging and serological markers enhanced both the sensitivity (87.31%) and specificity (92.31%) in predicting plaque stability, with an AUC of 0.9001.

Conclusion

Combining multi-modal imaging with serological markers provides a more comprehensive evaluation of atherosclerotic plaque features.

Potential biomarkers and immune characteristics for polycythemia vera-related atherosclerosis using bulk RNA and single-cell RNA datasets: a combined comprehensive bioinformatics and machine learning analysis

Background

Polycythemia vera (PV) is a myeloproliferative disease characterized by significantly higher hemoglobin levels and positivity for JAK2 mutation. Thrombosis is the main risk event of this disease. Atherosclerosis (AS) can markedly increase the risk of arterial thrombosis in patients with PV. The objectives of our study were to identify potential biomarkers for PV-related AS and to explore the molecular biological association between PV and AS.

Methods

We extracted microarray datasets from the Gene Expression Omnibus (GEO) dataset for PV and AS. Common differentially expressed genes (CGs) were identified by differential expression analysis. Functional enrichment and protein-protein interaction (PPI) networks were constructed from the CG by random forest models using LASSO regression to identify pathogenic genes and their underlying processes in PV-related AS. The expression of potential biomarkers was validated using an external dataset. A diagnostic nomogram was constructed based on potential biomarkers to predict PV-related AS, and its diagnostic performance was assessed using ROC, calibration, and decision curve analyses. Subsequently, we used single-cell gene set enrichment analysis (GSEA) to analyze the immune signaling pathways associated with potential biomarkers. We also performed immune infiltration analysis of AS with "CIBERSORT" and calculated Pearson's correlation coefficients for potential biomarkers and infiltrating immune cells. Finally, we observed the expression of potential biomarkers in immune cells based on the single-cell RNA dataset.

Results

Fifty-two CGs were identified based on the intersection between up-regulated and down-regulated genes in PV and AS. Most biological processes associated with CGs were cytokines and factors associated with chemotaxis of immune cells. The PPI analysis identified ten hub genes, and of these, CCR1 and MMP9 were selected as potential biomarkers with which to construct a diagnostic model using machine learning methods and external dataset validation. These biomarkers could regulate Toll-like signaling, NOD-like signaling, and chemokine signaling pathways associated with AS. Finally, we determined that these potential biomarkers had a strong correlation with macrophage M0 infiltration. Further, the potential biomarkers were highly expressed in macrophages from patients with AS.

Conclusion

We identified two CGs (CCR1 and MMP9) as potential biomarkers for PV-related AS and established a diagnostic model based on them. These results may provide insight for future experimental studies for the diagnosis and treatment of PV-related AS.

Identification of key biomarkers of endothelial dysfunction in hypertension with carotid atherosclerosis based on WGCNA and the LASSO algorithm

Background

Endothelial dysfunction is the early stage of carotid atherosclerosis (CAS) in patients with hypertension. It is worth identifying the potential hub genes of endothelial dysfunction to elucidate pathological mechanism in the progression of the disease.

Method

We obtained gene expression profiles of GSE43292 from the Gene Expression Omnibus (GEO) database. Hub genes associated with CAS were identified through weighted gene correlation network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) regression. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to explore potential biological mechanisms and signaling pathways. Finally, in vitro experiments on human umbilical vein endothelial cells (HUVECs) were conducted to validate these hub genes.

Results

The microarray dataset GSE43292 included 32 CAS plaques samples and corresponding macroscopically intact tissues from patients with hypertension. A total of 161 differentially expressed genes were discovered. Through WGCNA analysis, the gray60 module emerged as the most significant module associated with clinical features. The GO and KEGG enrichment analyses of genes in the gray60 module highlighted the substantial involvement of immune response-related signaling pathways. Two key hub genes (CCR1 and NCKAP1L) were pinpointed via LASSO regression. We found a significant increase in the mRNA expression level of the hub genes in oxidized low density lipoprotein (ox-LDL) treated HUVECs.

Conclusions

Our study indicated that the hub genes related to immune responses are involved in the development of CAS. Two hub genes (CCR1 and NCKAP1L) of endothelial dysfunction were identified. These genes may provide a valuable therapeutic target of CAS in patients with hypertension.

Sexual dimorphism in atherosclerotic plaques of aged Ldlr-/- mice

BACKGROUND

Atherosclerosis, the main underlying pathology of cardiovascular disease, is a chronic inflammatory disease characterized by lipid accumulation and immune cell responses in the vascular wall, resulting in plaque formation. It is well-known that atherosclerosis prevalence and manifestation vary by sex. However, sexual dimorphism in the immune landscape of atherosclerotic plaques has up to date not been studied at high-resolution. In this study, we investigated sex-specific differences in atherosclerosis development and the immunological landscape of aortas at single-cell level in aged Ldlr-/- mice.

METHODS

We compared plaque morphology between aged male and female chow diet-fed Ldlr-/- mice (22 months old) with histological analysis. Using single-cell RNA-sequencing and flow cytometry on CD45+ immune cells from aortas of aged Ldlr-/- mice, we explored the immune landscape in the atherosclerotic environment in males and females.

RESULTS

We show that plaque volume is comparable in aged male and female mice, and that plaques in aged female mice contain more collagen and cholesterol crystals, but less necrotic core and macrophage content compared to males. We reveal increased immune cell infiltration in female aortas and found that expression of pro-atherogenic markers and inflammatory signaling pathways was enriched in plaque immune cells of female mice. Particularly, female aortas show enhanced activation of B cells (Egr1, Cd83, Cd180), including age-associated B cells, in addition to an increased M1/M2 macrophage ratio, where Il1b+ M1-like macrophages display a more pro-inflammatory phenotype (Nlrp3, Cxcl2, Mmp9) compared to males. In contrast, increased numbers of age-associated Gzmk+CD8+ T cells, dendritic cells, and Trem2+ macrophages were observed in male aortas.

CONCLUSIONS

Altogether, our findings highlight that sex is a variable that contributes to immunological differences in the atherosclerotic plaque environment in mice and provide valuable insights for further preclinical studies into the impact of sex on the pathophysiology of atherosclerosis.

Role of the CCL5 and Its Receptor, CCR5, in the Genesis of Aldosterone-Induced Hypertension, Vascular Dysfunction, and End-Organ Damage

BACKGROUND

Aldosterone has been described to initiate cardiovascular diseases by triggering exacerbated sterile vascular inflammation. The functions of CCL5 (C-C motif chemokine ligand 5) and its receptor CCR5 (C-C motif chemokine receptor 5) are well known in infectious diseases, their contributions to aldosterone-induced vascular injury and hypertension remain unknown.

METHODS

We analyzed the vascular profile, blood pressure, and renal damage in wild-type (CCR5+/+) and CCR5 knockout (CCR5-/-) mice treated with aldosterone (600 µg/kg per day for 14 days) while receiving 1% saline to drink. Vascular function was analyzed in aorta and mesenteric arteries, blood pressure was measured by telemetry and renal injury and inflammation were analyzed via histology and flow cytometry. Endothelial cells were used to study the molecular signaling whereby CCL5 induces endothelial dysfunction.

RESULTS

Aldosterone treatment resulted in exaggerated CCL5 circulating levels and vascular CCR5 expression in CCR5+/+ mice accompanied by endothelial dysfunction, hypertension, and renal inflammation and damage. CCR5-/- mice were protected from these aldosterone-induced effects. Mechanistically, we demonstrated that CCL5 increased NOX1 (NADPH oxidase 1) expression, reactive oxygen species formation, NFκB (nuclear factor kappa B) activation, and inflammation and reduced NO production in isolated endothelial cells. These effects were abolished by antagonizing CCR5 with Maraviroc. Finally, aorta incubated with CCL5 displayed severe endothelial dysfunction, which is prevented by blocking NOX1, NFκB, or CCR5.

CONCLUSIONS

Our data demonstrate that CCL5/CCR5, through activation of NFκB and NOX1, is critically involved in aldosterone-induced vascular and renal damage and hypertension placing CCL5 and CCR5 as potential therapeutic targets for conditions characterized by aldosterone excess.

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

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

Sulfoconjugation of protein peptides and glycoproteins in physiology and diseases

Protein sulfoconjugation, or sulfation, represents a critical post-translational modification (PTM) process that involves the attachment of sulfate groups to various positions of substrates within the protein peptides or glycoproteins. This process plays a dynamic and complex role in many physiological and pathological processes. Here, we summarize the importance of sulfation in the fields of oncology, virology, drug-induced liver injury (DILI), inflammatory bowel disease (IBD), and atherosclerosis. In oncology, sulfation is involved in tumor initiation, progression, and migration. In virology, sulfation influences viral entry, replication, and host immune response. In DILI, sulfation is associated with the incidence of DILI, where altered sulfation affects drug metabolism and toxicity. In IBD, dysregulation of sulfation compromises mucosal barrier and immune response. In atherosclerosis, sulfation influences the development of atherosclerosis by modulating the accumulation of lipoprotein, and the inflammation, proliferation, and migration of smooth muscle cells. The current review underscores the importance of further research to unravel the underlying mechanisms and therapeutic potential of targeting sulfoconjugation in various diseases. A better understanding of sulfation could facilitate the emergence of innovative diagnostic or therapeutic strategies.

Role Of The C-C Motif Chemokine Ligand 5 (CCL5) And Its Receptor, C-C Motif Chemokine Receptor 5 (CCR5) In The Genesis Of Aldosterone-induced Hypertension, Vascular Dysfunction, And End-organ Damage

Background

Aldosterone, a mineralocorticoid steroid hormone, has been described to initiate cardiovascular diseases by triggering exacerbated sterile vascular inflammation. The functions of C-C Motif Chemokine Ligand 5 (CCL5) and its receptor, C-C Motif Chemokine Receptor 5 (CCR5), are well known in infectious diseases, but their roles in the genesis of aldosterone-induced vascular injury and hypertension are unknown.

Methods

We analyzed the vascular profile, blood pressure, and renal damage in wild-type (CCR5+/+) and CCR5 knockout (CCR5-/-) mice treated with aldosterone (600 μg/kg/day for 14 days) while receiving 1% saline to drink.

Results

Here, we show that CCR5 plays a central role in aldosterone-induced vascular injury, hypertension, and renal damage. Long-term infusion of aldosterone in CCR5+/+ mice resulted in exaggerated CCL5 circulating levels and vascular CCR5 expression. Aldosterone treatment also triggered vascular injury, characterized by endothelial dysfunction and inflammation, hypertension, and renal damage. Mice lacking CCR5 were protected from aldosterone-induced vascular damage, hypertension, and renal injury. Mechanistically, we demonstrated that CCL5 increased NADPH oxidase 1 (Nox1) expression, reactive oxygen species (ROS) formation, NFκB activation, and inflammation and reduced nitric oxide production in isolated endothelial cells. These effects were abolished by antagonizing CCR5 with Maraviroc. Finally, aortae incubated with CCL5 displayed severe endothelial dysfunction, which is prevented by blocking Nox1, NFκB, or with Maraviroc treatment.

Conclusions

Our data demonstrate that CCL5/CCR5, through activation of NFkB and Nox1, is critically involved in aldosterone-induced vascular and renal damage and hypertension. Our data place CCL5 and CCR5 as potential targets for therapeutic interventions in conditions with aldosterone excess.

Association of Soluble Markers of Inflammation With Peri-coronary Artery Inflammation in People With and Without HIV Infection and Without Cardiovascular Disease

Background

Inflammation is linked to elevated cardiovascular disease (CVD) risk in people with HIV (PWH) on antiretroviral therapy (ART). Fat attenuation index (FAI) is a measure of peri-coronary inflammation that independently predicts CVD risk in HIV-uninfected persons. Whether FAI is associated with soluble inflammatory markers is unknown.

Methods

Plasma levels of inflammatory markers were measured in 58 PWH and 16 controls without current symptoms or prior known CVD who underwent coronary computed tomography angiography and had FAI measurements. A cross-sectional analysis was performed, and associations of markers with FAI values of the right coronary artery (RCA) and left anterior descending artery (LAD) were assessed using multivariable regression models adjusted for the potential confounders age, sex, race, low-density lipoprotein cholesterol, body mass index, and use of lipid-lowering medication.

Results

Several inflammatory markers had significant associations with RCA or LAD FAI in adjusted models, including sCD14, sCD163, TNFR-I, and TNFR-II, CCL5, CX3CL1, IP-10.

Conclusions

The associations between indices of systemic and peri-coronary inflammation are novel and suggest that these systemic markers and FAI together are promising noninvasive biomarkers that can be applied to assess asymptomatic CVD in people with and without HIV; they also may be useful tools to evaluate effects of anti-inflammatory interventions.

Monocyte-endothelial cell interactions in vascular and tissue remodeling

Monocytes are circulating leukocytes of innate immunity derived from the bone marrow that interact with endothelial cells under physiological or pathophysiological conditions to orchestrate inflammation, angiogenesis, or tissue remodeling. Monocytes are attracted by chemokines and specific receptors to precise areas in vessels or tissues and transdifferentiate into macrophages with tissue damage or infection. Adherent monocytes and infiltrated monocyte-derived macrophages locally release a myriad of cytokines, vasoactive agents, matrix metalloproteinases, and growth factors to induce vascular and tissue remodeling or for propagation of inflammatory responses. Infiltrated macrophages cooperate with tissue-resident macrophages during all the phases of tissue injury, repair, and regeneration. Substances released by infiltrated and resident macrophages serve not only to coordinate vessel and tissue growth but cellular interactions as well by attracting more circulating monocytes (e.g. MCP-1) and stimulating nearby endothelial cells (e.g. TNF-α) to expose monocyte adhesion molecules. Prolonged tissue accumulation and activation of infiltrated monocytes may result in alterations in extracellular matrix turnover, tissue functions, and vascular leakage. In this review, we highlight the link between interactions of infiltrating monocytes and endothelial cells to regulate vascular and tissue remodeling with a special focus on how these interactions contribute to pathophysiological conditions such as cardiovascular and chronic liver diseases.

In Vitro Anti-Inflammatory and Vasculoprotective Effects of Red Cell Extract from the Black Sea Urchin Arbacia lixula

Sea urchins have emerged as an important source of bioactive compounds with anti-inflammatory and antioxidant properties relevant to human health. Since inflammation is a crucial pathogenic process in the development and progression of atherosclerosis, we here assessed the potential anti-inflammatory and vasculoprotective effects of coelomic red-cell methanolic extract of the black sea urchin Arbacia lixula in an in vitro model of endothelial cell dysfunction. Human microvascular endothelial cells (HMEC-1) were pretreated with A. lixula red-cell extract (10 and 100 μg/mL) before exposure to the pro-inflammatory cytokine tumor necrosis factor (TNF)-α. The extract was non-toxic after 24 h cell treatment and was characterized by antioxidant power and phenol content. The TNF-α-stimulated expression of adhesion molecules (VCAM-1, ICAM-1) and cytokines/chemokines (MCP-1, CCL-5, IL-6, IL-8, M-CSF) was significantly attenuated by A. lixula red-cell extract. This was functionally accompanied by a reduction in monocyte adhesion and chemotaxis towards activated endothelial cells. At the molecular level, the tested extract significantly counteracted the TNF-α-stimulated activation of the pro-inflammatory transcription factor NF-κB. These results provide evidence of potential anti-atherosclerotic properties of A. lixula red-cell extract, and open avenues in the discovery and development of dietary supplements and/or drugs for the prevention or treatment of cardiovascular diseases.

The diverse roles of macrophages in metabolic inflammation and its resolution

Macrophages are one of the most functionally diverse immune cells, indispensable to maintain tissue integrity and metabolic health. Macrophages perform a myriad of functions ranging from promoting inflammation, through inflammation resolution to restoring and maintaining tissue homeostasis. Metabolic diseases encompass a growing list of diseases which develop from a mix of genetics and environmental cues leading to metabolic dysregulation and subsequent inflammation. In this review, we summarize the contributions of macrophages to four metabolic conditions-insulin resistance and adipose tissue inflammation, atherosclerosis, non-alcoholic fatty liver disease and neurodegeneration. The role of macrophages is complex, yet they hold great promise as potential therapies to address these growing health concerns.

Monocyte chemokine receptors as therapeutic targets in cardiovascular diseases

Chemokine receptors are fundamental in many processes related to cardiovascular diseases, such as monocyte migration to vessel walls, cell adhesion, and angiogenesis, among others. Even though many experimental studies have shown the utility of blocking these receptors or their ligands in the treatment of atherosclerosis, the findings in clinical research are still poor. Thus, in the current review we aimed to describe some promising results concerning the blockade of chemokine receptors as therapeutic targets in the treatment of cardiovascular diseases and also to discuss some challenges that need to be overcome before using these strategies in clinical practice.

Characteristics and pathogenesis of chemokines in the post-stroke stage

Chemokines, as small molecular proteins, play a crucial role in the immune and inflammatory responses after stroke. A large amount of evidence showed chemokines and their receptors were increasingly recognized as potential targets for stroke treatment, which were involved in the processing of neovascularization, neurogenesis, and neural network reconstruction. In this review, we summarized the characteristics of chemokine alterations throughout the post-stroke nerve repair phase to gain insight into the pathological mechanisms of chemokines and find effective therapeutic targets for stroke.

Elevated RANTES levels are associated with increased risk of cerebral atherosclerotic stenosis

BACKGROUND

Cerebral atherosclerotic stenosis (CAS) is a significant factor in the development of acute ischemic stroke (AIS). Previous studies have reported that cytokines are involved in atherosclerotic diseases, although the relationship between serum levels of the chemokine RANTES (regulated on activation, normal T-cell expressed and secreted) and the presence of CAS remains unclear.

METHODS

In total, 127 participants (65 non-AIS controls and 62 patients with AIS) were involved in this study. CAS was defined as the presence of ≥ 50% stenosis in major intracranial or extracranial artery by a Digital Substraction Angiography (DSA) examination, and we classified all participants into four groups according to stroke and CAS status. Serum concentrations of 8 cytokines, including RANTES, were measured by the Human ProcartaPlex Multiplex Immunoassay Kit.

RESULTS

Seventy-eight participants (61.41%) had CAS, of which 39 cases with AIS and 39 case with non-AIS. Patients with CAS had higher RANTES levels compared to non-CAS patients in both the non-AIS group (10.54 ± 0.80 vs. 13.20 ± 0.71, p = 0.016) and stroke group (11.96 ± 0.87 vs. 15.03 ± 0.75, p = 0.011), and multivariate logistic regression analysis showed that the RANTES level is independently associated with CAS in both the non-AIS group (adjusted odds ratio (OR), 1.07; 95% CI, 1.02-1.12, P = 0.004) and stroke group (adjusted OR, 1.32; 95% CI, 1.10-1.58, P = 0.003).

CONCLUSION

Patients with CAS have higher levels of serum RANTES than non-CAS patients regardless of stroke status suggesting that RANTES may play an important role in the formation of CAS.

Identification of Key Genes as Early Warning Signals of Acute Myocardial Infarction Based on Weighted Gene Correlation Network Analysis and Dynamic Network Biomarker Algorithm

Purpose

The specific mechanisms and biomarkersunderlying the progression of stable coronary artery disease (CAD) to acute myocardial infarction (AMI) remain unclear. The current study aims to explore novel gene biomarkers associated with CAD progression by analyzing the transcriptomic sequencing data of peripheral blood monocytes in different stages of CAD.

Material and Methods

A total of 24 age- and sex- matched patients at different CAD stages who received coronary angiography were enrolled, which included 8 patients with normal coronary angiography, 8 patients with angiographic intermediate lesion, and 8 patients with AMI. The RNA from peripheral blood monocytes was extracted and transcriptome sequenced to analyze the gene expression and the differentially expressed genes (DEG). A Gene Oncology (GO) enrichment analysis was performed to analyze the biological function of genes. Weighted gene correlation network analysis (WGCNA) was performed to classify genes into several gene modules with similar expression profiles, and correlation analysis was carried out to explore the association of each gene module with a clinical trait. The dynamic network biomarker (DNB) algorithm was used to calculate the key genes that promote disease progression. Finally, the overlapping genes between different analytic methods were explored.

Results

WGCNA analysis identified a total of nine gene modules, of which two modules have the highest positive association with CAD stages. GO enrichment analysis indicated that the biological function of genes in these two gene modules was closely related to inflammatory response, which included T-cell activation, cell response to inflammatory stimuli, lymphocyte activation, cytokine production, and the apoptotic signaling pathway. DNB analysis identified a total of 103 genes that may play key roles in the progression of atherosclerosis plaque. The overlapping genes between DEG/WGCAN and DNB analysis identified the following 13 genes that may play key roles in the progression of atherosclerosis disease: SGPP2, DAZAP2, INSIG1, CD82, OLR1, ARL6IP1, LIMS1, CCL5, CDK7, HBP1, PLAU, SELENOS, and DNAJB6.

Conclusions

The current study identified a total of 13 genes that may play key roles in the progression of atherosclerotic plaque and provides new insights for early warning biomarkers and underlying mechanisms underlying the progression of CAD.

Single-Cell Analysis Uncovers Osteoblast Factor Growth Differentiation Factor 10 as Mediator of Vascular Smooth Muscle Cell Phenotypic Modulation Associated with Plaque Rupture in Human Carotid Artery Disease

(1) Background: Vascular smooth muscle cells (VSMCs) undergo a complex phenotypic switch in response to atherosclerosis environmental triggers, contributing to atherosclerosis disease progression. However, the complex heterogeneity of VSMCs and how VSMC dedifferentiation affects human carotid artery disease (CAD) risk has not been clearly established. (2) Method: A single-cell RNA sequencing analysis of CD45⁻ cells derived from the atherosclerotic aorta of Apolipoprotein E-deficient (Apoe^−/−) mice on a normal cholesterol diet (NCD) or a high cholesterol diet (HCD), respecting the site-specific predisposition to atherosclerosis was performed. Growth Differentiation Factor 10 (GDF10) role in VSMCs phenotypic switch was investigated via flow cytometry, immunofluorescence in human atherosclerotic plaques. (3) Results: scRNAseq analysis revealed the transcriptomic profile of seven clusters, five of which showed disease-relevant gene signature of VSMC macrophagic calcific phenotype, VSMC mesenchymal chondrogenic phenotype, VSMC inflammatory and fibro-phenotype and VSMC inflammatory phenotype. Osteoblast factor GDF10 involved in ossification and osteoblast differentiation emerged as a hallmark of VSMCs undergoing phenotypic switch. Under hypercholesteremia, GDF10 triggered VSMC osteogenic switch in vitro. The abundance of GDF10 expressing osteogenic-like VSMCs cells was linked to the occurrence of carotid artery disease (CAD) events. (4) Conclusions: Taken together, these results provide evidence about GDF10-mediated VSMC osteogenic switch, with a likely detrimental role in atherosclerotic plaque stability.

Single-Cell RNA-Seq Reveals a Crosstalk between Hyaluronan Receptor LYVE-1-Expressing Macrophages and Vascular Smooth Muscle Cells

Background: Atherosclerosis is a chronic inflammatory disease where macrophages participate in the progression of the disease. However, the role of resident-like macrophages (res-like) in the atherosclerotic aorta is not completely understood. Methods: A single-cell RNA sequencing analysis of CD45⁺ leukocytes in the atherosclerotic aorta of apolipoprotein E–deficient (Apoe^−/−) mice on a normal cholesterol diet (NCD) or a high cholesterol diet (HCD), respecting the side-to-specific predisposition to atherosclerosis, was performed. A population of res-like macrophages expressing hyaluronan receptor LYVE-1 was investigated via flow cytometry, co-culture experiments, and immunofluorescence in human atherosclerotic plaques from carotid artery disease patients (CAD). Results: We identified 12 principal leukocyte clusters with distinct atherosclerosis disease-relevant gene expression signatures. LYVE-1⁺ res-like macrophages, expressing a high level of CC motif chemokine ligand 24 (CCL24, eotaxin-2), expanded under hypercholesteremia in Apoe^−/− mice and promoted VSMC phenotypic modulation to osteoblast/chondrocyte-like cells, ex vivo, in a CCL24-dependent manner. Moreover, the abundance of LYVE-1⁺CCL24⁺ macrophages and elevated systemic levels of CCL24 were associated with vascular calcification and CAD events. Conclusions: LYVE-1 res-like macrophages, via the secretion of CCL24, promote the transdifferentiation of VSMC to osteogenic-like cells with a possible role in vascular calcification and likely a detrimental role in atherosclerotic plaque destabilization.

Where the Action Is-Leukocyte Recruitment in Atherosclerosis

Atherosclerosis is the leading cause of death worldwide and leukocyte recruitment is a key element of this phenomenon, thus allowing immune cells to enter the arterial wall. There, in concert with accumulating lipids, the invading leukocytes trigger a plethora of inflammatory responses which promote the influx of additional leukocytes and lead to the continued growth of atherosclerotic plaques. The recruitment process follows a precise scheme of tethering, rolling, firm arrest, crawling and transmigration and involves multiple cellular and subcellular players. This review aims to provide a comprehensive up-to-date insight into the process of leukocyte recruitment relevant to atherosclerosis, each from the perspective of endothelial cells, monocytes and macrophages, neutrophils, T lymphocytes and platelets. In addition, therapeutic options targeting leukocyte recruitment into atherosclerotic lesions-or potentially arising from the growing body of insights into its precise mechanisms-are highlighted.

NLRP3 Inflammasome Activation Controls Vascular Smooth Muscle Cells Phenotypic Switch in Atherosclerosis

(1) Background: Monocytes and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome orchestrate lipid-driven amplification of vascular inflammation promoting the disruption of the fibrous cap. The components of the NLRP3 inflammasome are expressed in macrophages and foam cells within human carotid atherosclerotic plaques and VSMCs in hypertension. Whether monocytes and NLRP3 inflammasome activation are direct triggers of VSMC phenotypic switch and plaque disruption need to be investigated. (2) Methods: The direct effect of oxLDL-activated monocytes in VSMCs co-cultured system was demonstrated via flow cytometry, qPCR, ELISA, caspase 1, and pyroptosis assay. Aortic roots of VSMCs lineage tracing mice fed normal or high cholesterol diet and human atherosclerotic plaques were used for immunofluorescence quantification of NLRP3 inflammasome activation/VSMCs phenotypic switch. (3) Results: OxLDL-activated monocytes reduced α-SMA, SM22α, Oct-4, and upregulation of KLF-4 and macrophage markers MAC2, F4/80 and CD68 expression as well as caspase 1 activation, IL-1β secretion, and pyroptosis in VSMCs. Increased caspase 1 and IL-1β in phenotypically modified VSMCs was detected in the aortic roots of VSMCs lineage tracing mice fed high cholesterol diet and in human atherosclerotic plaques from carotid artery disease patients who experienced a stroke. (4) Conclusions: Taken together, these results provide evidence that monocyte promote VSMC phenotypic switch through VSMC NLRP3 inflammasome activation with a likely detrimental role in atherosclerotic plaque stability in human atherosclerosis.

Melanocortin 1 Receptor Deficiency in Hematopoietic Cells Promotes the Expansion of Inflammatory Leukocytes in Atherosclerotic Mice

Melanocortin receptor 1 (MC1-R) is expressed in leukocytes, where it mediates anti-inflammatory actions. We have previously observed that global deficiency of MC1-R signaling perturbs cholesterol homeostasis, increases arterial leukocyte accumulation and accelerates atherosclerosis in apolipoprotein E knockout (Apoe^-/-) mice. Since various cell types besides leukocytes express MC1-R, we aimed at investigating the specific contribution of leukocyte MC1-R to the development of atherosclerosis. For this purpose, male Apoe^-/- mice were irradiated, received bone marrow from either female Apoe^-/- mice or MC1-R deficient Apoe^-/- mice (Apoe^-/- Mc1r^e/e) and were analyzed for tissue leukocyte profiles and atherosclerotic plaque phenotype. Hematopoietic MC1-R deficiency significantly elevated total leukocyte counts in the blood, bone marrow and spleen, an effect that was amplified by feeding mice a cholesterol-rich diet. The increased leukocyte counts were largely attributable to expanded lymphocyte populations, particularly CD4⁺ T cells. Furthermore, the number of monocytes was elevated in Apoe^-/- Mc1r^e/e chimeric mice and it paralleled an increase in hematopoietic stem cell count in the bone marrow. Despite robust leukocytosis, atherosclerotic plaque size and composition as well as arterial leukocyte counts were unaffected by MC1-R deficiency. To address this discrepancy, we performed an in vivo homing assay and found that MC1-R deficient CD4⁺ T cells and monocytes were preferentially entering the spleen rather than homing in peri-aortic lymph nodes. This was mechanistically associated with compromised chemokine receptor 5 (CCR5)-dependent migration of CD4⁺ T cells and a defect in the recycling capacity of CCR5. Finally, our data demonstrate for the first time that CD4⁺ T cells also express MC1-R. In conclusion, MC1-R regulates hematopoietic stem cell proliferation and tissue leukocyte counts but its deficiency in leukocytes impairs cell migration via a CCR5-dependent mechanism.

The potential targets in immunotherapy of atherosclerosis

Cardiovascular disease is the most common cause of death, which has the highest mortality rate worldwide. Although a diverse range of inflammatory diseases can affect the cardiovascular system, however, heart failure and stroke occur due to atherosclerosis. Atherosclerosis is a chronic autoinflammatory disease of small to large vessels in which different immune mediators are involved in lipid plaque formation and inflammatory vascular remodeling process. A better understanding of the pathophysiology of atherosclerosis may lead to uncovering immunomodulatory therapies. Despite present diagnostic and therapeutic methods, the lack of immunotherapy in the prevention and treatment of atherosclerosis is perceptible. In this review, we will discuss the promising immunological-based therapeutics and novel preventive approaches for atherosclerosis. This study could provide new insights into a better perception of targeted therapeutic pathways and biological therapies.

GDF-15 Suppresses Atherosclerosis by Inhibiting oxLDL-Induced Lipid Accumulation and Inflammation in Macrophages

The growth differentiation factor-15 (GDF-15) may be involved in atherosclerosis. However, the role of GDF-15 in atherosclerosis remains unclear. The main goal of this study was to verify the role and mechanism of GDF-15 in atherogenesis. We first compared the serum GDF-15 level between patients with coronary atherosclerosis and healthy people. And then one ApoE^-/- mouse model of atherosclerosis was used to explore the effects of GDF-15 on oxidized low-density lipoprotein (oxLDL) accumulation, atherosclerosis-related gene expression, and lipid accumulation-related protein expression in mouse macrophages. As a result, the level of serum GDF-15 in patients with coronary atherosclerosis was significantly higher than that in healthy people. In the mouse model, GDF-15 expression was elevated in the core of plaque, and it was secreted mainly by the macrophages. In addition, GDF-15 decreased oxLDL-induced lipid accumulation and inflammation activation in macrophages. GDF-15 decreased the mRNA expressions of CD36, LOX1, and TLR4 that are associated with lipoprotein accumulation in macrophages. Further study showed that GDF-15 might suppress oxLDL-induced lipoprotein accumulation via inhibiting CD36 and LOX1 and decrease inflammation in macrophages by inhibiting TLR4. Thus, GDF-15 may suppress atherosclerosis and plaque formation by inhibiting lipoprotein accumulation and inflammation activation.

Key Chemokine Pathways in Atherosclerosis and Their Therapeutic Potential

The search to improve therapies to prevent or treat cardiovascular diseases (CVDs) rages on, as CVDs remain a leading cause of death worldwide. Here, the main cause of CVDs, atherosclerosis, and its prevention, take center stage. Chemokines and their receptors have long been known to play an important role in the pathophysiological development of atherosclerosis. Their role extends from the initiation to the progression, and even the potential regression of atherosclerotic lesions. These important regulators in atherosclerosis are therefore an obvious target in the development of therapeutic strategies. A plethora of preclinical studies have assessed various possibilities for targeting chemokine signaling via various approaches, including competitive ligands and microRNAs, which have shown promising results in ameliorating atherosclerosis. Developments in the field also include detailed imaging with tracers that target specific chemokine receptors. Lastly, clinical trials revealed the potential of various therapies but still require further investigation before commencing clinical use. Although there is still a lot to be learned and investigated, it is clear that chemokines and their receptors present attractive yet extremely complex therapeutic targets. Therefore, this review will serve to provide a general overview of the connection between various chemokines and their receptors with atherosclerosis. The different developments, including mouse models and clinical trials that tackle this complex interplay will also be explored.

Comprehensive analysis of dysregulated genes associated with atherosclerotic plaque destabilization

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

Immunotherapy and cardiovascular diseases (CVD): novel avenues for immunotherapeutic approaches

As current therapies for cardiovascular disease (CVD), predominantly based on lipid lowering, still face an unacceptable residual risk, novel treatment strategies are being explored. Besides lipids, inflammatory processes play a major role in the pathogenesis of atherosclerosis, the underlying cause of the majority of CVD. The first clinical trials targeting the interleukin-1β-inflammasome axis have shown that targeting this pathway is successful in reducing cardiovascular events but did not decrease overall CVD mortality. Hence, novel and improved immunotherapeutics to treat CVD are being awaited. In this review we highlight novel immunotherapeutic approaches in CVD as well as future challenges ahead.

Anti-inflammatory and Immunomodulatory Therapies in Atherosclerosis

Hypercholesterolemia is a major risk factor in atherosclerosis development and lipid-lowering drugs (i.e., statins) remain the treatment of choice. Despite effective reduction of LDL cholesterol in patients, a residual cardiovascular risk persists in some individuals, highlighting the need for further therapeutic intervention. Recently, the CANTOS trial paved the way toward the development of specific therapies targeting inflammation, a key feature in atherosclerosis progression. The pre-existence of multiple drugs modulating both innate and adaptive immune responses has significantly accelerated the number of translational studies applying these drugs to atherosclerosis. Additional preclinical research has led to the discovery of new therapeutic targets, offering promising perspectives for the treatment and prevention of atherosclerosis. Currently, both drugs with selective targeting and broad unspecific anti-inflammatory effects have been tested. In this chapter, we aim to give an overview of current advances in immunomodulatory treatment approaches for atherosclerotic cardiovascular diseases.

Targeting the chemokine network in atherosclerosis

Chemokines and their receptors represent a potential target for immunotherapy in chronic inflammation. They comprise a large family of cytokines with chemotactic activity, and their cognate receptors are expressed on all cells of the body. This network dictates leukocyte recruitment and activation, angiogenesis, cell proliferation and maturation. Dysregulation of chemokine and chemokine receptor expression as well as function participates in many pathologies including cancer, autoimmune diseases and chronic inflammation. In atherosclerosis, a lipid-driven chronic inflammation of middle-sized and large arteries, chemokines and their receptors participates in almost all stages of the disease from initiation of fatty streaks to mature atherosclerotic plaque formation. Atherosclerosis and its complications are the main driver of mortality and morbidity in cardiovascular diseases (CVD). Hence, exploring new fields of therapeutic targeting of atherosclerosis is of key importance. This review gives an overview of the recent advances on the role of key chemokines and chemokine receptors in atherosclerosis, addresses chemokine-based biomarkers at biochemical, imaging and genetic level in human studies, and highlights the clinial trials targeting atherosclerosis.

Regulatory T Cell-Related Gene Biomarkers in the Deterioration of Atherosclerosis

Background: Regulatory T cells (Tregs) have shown to be protective against the development of atherosclerosis, a major pathological cause for cardiovascular events. Here, we aim to explore the roles of Tregs-related genes in atherosclerosis deterioration. Methods and Results: We downloaded the gene expression profile of 29 atherosclerotic samples from the Gene Expression Omnibus database with an accession number of GSE28829. The abundance of Tregs estimated by the CIBERSORT algorithm was negatively correlated with the atherosclerotic stage. Using the limma test and correlation analysis, a total of 159 differentially expressed Tregs-related genes (DETregRGs) between early and advanced atherosclerotic plaques were documented. Functional annotation analysis using the DAVID tool indicated that the DETregRGs were mainly enriched in inflammatory responses, immune-related mechanisms, and pathways such as complement and coagulation cascades, platelet activation, leukocyte trans-endothelial migration, vascular smooth muscle contraction, and so on. A protein-protein interaction network of the DETregRGs was then constructed, and five hub genes (PTPRC, C3AR1, CD53, TLR2, and CCR1) were derived from the network with node degrees ≥20. The expression patterns of these hub DETregRGs were further validated in several independent datasets. Finally, a single sample scoring method was used to build a gene signature for the five DETregRGs, which could distinguish patients with myocardial infarction from those with stable coronary disease. Conclusion: The results of this study will improve our understanding about the Tregs-associated molecular mechanisms in the progression of atherosclerosis and facilitate the discovery of novel biomarkers for acute cardiovascular events.

Assessment of medullary and extramedullary myelopoiesis in cardiovascular diseases

Recruitment of innate immune cells and their accumulation in the arterial wall and infarcted myocardium has been recognized as a central feature of atherosclerosis and cardiac ischemic injury, respectively. In both, steady state and under pathological conditions, majority of these cells have a finite life span and are continuously replenished from haematopoietic stem/progenitor cell pool residing in the bone marrow and extramedullary sites. While having a crucial role in the cardiovascular disease development, proliferation and differentiation of innate immune cells within haematopoietic compartments is greatly affected by the ongoing cardiovascular pathology. In the current review, we summarize key cells, processes and tissue compartments that are involved in myelopoiesis under the steady state, during atherosclerosis development and in myocardial infarction.

Role of myeloid-derived chemokine CCL5/RANTES at an early stage of atherosclerosis

One of the hallmarks of atherosclerosis is ongoing accumulation of macrophages in the artery intima beginning at disease onset. Monocyte recruitment contributes to increasing macrophage abundance at early stages of atherosclerosis. Although the chemokine CCL5 (RANTES) has been studied in atherosclerosis, its role in the recruitment of monocytes to early lesions has not been elucidated. We show that expression of Ccl5 mRNA, as well as other ligands of the CCR5 receptor (Ccl3 and Ccl4), is induced in the aortic intima of Ldlr^-/- mice 3 weeks after the initiation of cholesterol-rich diet (CRD)-induced hypercholesterolemia. En face immunostaining revealed that CCL5 protein expression is also upregulated at 3 weeks of CRD. Blockade of CCR5 significantly reduced monocyte recruitment to 3-week lesions, suggesting that chemokine signaling through CCR5 is critical. However, we observed that Ccl5-deficiency had no effect on early lesion formation and CCL5-blockade did not affect monocyte recruitment in Ldlr^-/- mice. Immunostaining of the lesions in Ldlr^-/- mice and reciprocal bone marrow transplantation (BMT) of Ccl5^+/+ and Ccl5^-/- mice revealed that CCL5 is expressed by both myeloid and endothelial cells. BMT experiments were carried out to determine if CCL5 produced by distinct cells has functions that may be concealed in Ccl5^-/-Ldlr^-/- mice. We found that hematopoietic cell-derived CCL5 regulates monocyte recruitment and the abundance of intimal macrophages in 3-week lesions of Ldlr^-/- mice but plays a minor role in 6-week lesions. Our findings suggest that there is a short window in early lesion formation during which myeloid cell-derived CCL5 has a critical role in monocyte recruitment and macrophage abundance.

CC Chemokine Receptor 5 Targeted Nanoparticles Imaging the Progression and Regression of Atherosclerosis Using Positron Emission Tomography/Computed Tomography

Chemokines and chemokine receptors play an important role in the initiation and progression of atherosclerosis by mediating the trafficking of inflammatory cells. Chemokine receptor 5 (CCR5) has major implications in promoting the development of plaques to advanced stage and related vulnerability. CCR5 antagonist has demonstrated the effective inhibition of atherosclerotic progression in mice, making it a potential biomarker for atherosclerosis management. To accurately determine CCR5 in vivo, we synthesized CCR5 targeted Comb nanoparticles through a modular design and construction strategy with control over the physiochemical properties and functionalization of CCR5 targeting peptide d-Ala-peptide T-amide (DAPTA-Comb). In vivo pharmacokinetic evaluation through 64Cu radiolabeling showed extended blood circulation of 64Cu-DAPTA-Combs conjugated with 10%, 25%, and 40% DAPTA. The different organ distribution profiles of the three nanoparticles demonstrated the effect of DAPTA on not only physicochemical properties but also targeting efficiency. In vivo positron emission tomography/computed tomography (PET/CT) imaging in an apolipoprotein E knockout mouse atherosclerosis model (ApoE-/-) showed that the three 64Cu-DAPTA-Combs could sensitively and specifically detect CCR5 along the progression of atherosclerotic lesions. In an ApoE-encoding adenoviral vector (AAV) induced plaque regression ApoE-/- mouse model, decreased monocyte recruitment, CD68+ macrophages, CCR5 expression, and plaque size were all associated with reduced PET signals, which not only further confirmed the targeting efficiency of 64Cu-DAPTA-Combs but also highlighted the potential of these targeted nanoparticles for atherosclerosis imaging. Moreover, the up-regulation of CCR5 and colocalization with CD68+ macrophages in the necrotic core of ex vivo human plaque specimens warrant further investigation for atherosclerosis prognosis.

System Genetics Including Causal Inference Identify Immune Targets for Coronary Artery Disease and the Lifespan

BACKGROUND

Randomized clinical trials indicate that the immune response plays a significant role in coronary artery disease (CAD), a disorder impacting the lifespan potential. However, the identification of targets critical to the immune response in atheroma is still hampered by a lack of solid inference.

METHODS

Herein, we implemented a system genetics approach to identify causally associated immune targets implicated in atheroma. We leveraged genome-wide association studies to perform mapping and Mendelian randomization to assess causal associations between gene expression in blood cells with CAD and the lifespan. Expressed genes (eGenes) were prioritized in network and in single-cell expression derived from plaque immune cells.

RESULTS

Among 840 CAD-associated blood eGenes, 37 were predicted causally associated with CAD and 6 were also associated with the parental lifespan in Mendelian randomization. In multivariable Mendelian randomization, the impact of eGenes on the lifespan potential was mediated by the CAD risk. Predicted causal eGenes were central in network. FLT1 and CCR5 were identified as targets of approved drugs, whereas 22 eGenes were deemed tractable for the development of small molecules and antibodies. Analyses of plaque immune single-cell expression identified predicted causal eGenes enriched in macrophages (GPX1, C4orf3) and involved in ligand-receptor interactions (CCR5).

CONCLUSIONS

We identified 37 blood eGenes predicted causally associated with CAD. The predicted expression for 6 eGenes impacted the lifespan potential through the risk of CAD. Prioritization based on network, annotations, and single-cell expression identified targets deemed tractable for the development of drugs and for drug repurposing.

Follicular regulatory helper T cells control the response of regulatory B cells to a high-cholesterol diet

AIMS

B cell functions in the process of atherogenesis have been investigated but several aspects remain to be clarified.

METHODS AND RESULTS

In this study, we show that follicular regulatory helper T cells (TFR) control regulatory B cell (BREG) populations in Apoe-/- mice models on a high-cholesterol diet (HCD). Feeding mice with HCD resulted in up-regulation of TFR and BREG cell populations, causing the suppression of proatherogenic follicular helper T cell (TFH) response. TFH cell modulation is correlated with the growth of atherosclerotic plaque size in thoracoabdominal aortas and aortic root plaques, suggesting that TFR cells are atheroprotective. During adoptive transfer experiments, TFR cells transferred into HCD mice decreased TFH cell populations, atherosclerotic plaque size, while BREG cell population and lymphangiogenesis are significantly increased.

CONCLUSION

Our results demonstrate that, through different strategies, both TFR and TFH cells modulate anti- and pro-atherosclerotic immune processes in an Apoe-/- mice model since TFR cells are able to regulate both TFH and BREG cell populations as well as lymphangiogenesis and lipoprotein metabolism.

Inflammatory Cell Recruitment in Cardiovascular Disease

Atherosclerosis, the main underlying pathology for myocardial infarction and stroke, is a chronic inflammatory disease of middle-sized to large arteries that is initiated and maintained by leukocytes infiltrating into the subendothelial space. It is now clear that the accumulation of pro-inflammatory leukocytes drives progression of atherosclerosis, its clinical complications, and directly modulates tissue-healing in the infarcted heart after myocardial infarction. This inflammatory response is orchestrated by multiple soluble mediators that enhance inflammation systemically and locally, as well as by a multitude of partially tissue-specific molecules that regulate homing, adhesion, and transmigration of leukocytes. While numerous experimental studies in the mouse have refined our understanding of leukocyte accumulation from a conceptual perspective, only a few anti-leukocyte therapies have been directly validated in humans. Lack of tissue-tropism of targeted factors required for leukocyte accumulation and unspecific inhibition strategies remain the major challenges to ultimately translate therapies that modulate leukocytes accumulation into clinical practice. Here, we carefully describe receptor and ligand pairs that guide leukocyte accumulation into the atherosclerotic plaque and the infarcted myocardium, and comment on potential future medical therapies.

Inflammatory Chemokines in Atherosclerosis

Atherosclerosis is a long-term, chronic inflammatory disease of the vessel wall leading to the formation of occlusive or rupture-prone lesions in large arteries. Complications of atherosclerosis can become severe and lead to cardiovascular diseases (CVD) with lethal consequences. During the last three decades, chemokines and their receptors earned great attention in the research of atherosclerosis as they play a key role in development and progression of atherosclerotic lesions. They orchestrate activation, recruitment, and infiltration of immune cells and subsequent phenotypic changes, e.g., increased uptake of oxidized low-density lipoprotein (oxLDL) by macrophages, promoting the development of foam cells, a key feature developing plaques. In addition, chemokines and their receptors maintain homing of adaptive immune cells but also drive pro-atherosclerotic leukocyte responses. Recently, specific targeting, e.g., by applying cell specific knock out models have shed new light on their functions in chronic vascular inflammation. This article reviews recent findings on the role of immunomodulatory chemokines in the development of atherosclerosis and their potential for targeting.

Identification of different cell clusters in the endothelium of atherosclerotic vessels and determination of inter-cluster gradient of proliferative and inflammatory activity as new diagnostic markers

To characterize atherogenesis functionally, we studied the functional heterogeneity of endotheliocytes in carotid vessels with atherosclerotic plaques and identified several distinct cell clusters. We measured the Ki-67 labeling index (Ki-67 LI), percentage of Bcl-2 cells (CP) and expression of CCL5, IL 6 and VCAM1 in each cell cluster. We also investigated how these indicators change when the plaque becomes unstable and how they affect the risk of adverse cerebrovascular events in patients. We evaluated the inter-cluster gradient of marker activity and its relation to patient prognosis. We identified five endothelial clusters: the under plaque cluster (UPC), peripheral cluster (PC), marginal cluster (MC), transient cluster (TC) and outside plaque cluster (OC). The UPC exhibited the greatest proliferative, proinflammatory and adhesive activity, but low anti-apoptotic activity. The PC exhibited the second greatest proliferative, adhesive and proinflammatory activity. Progression of atherosclerosis and transition of a stable atherosclerotic plaque to an unstable one was accompanied by increased expression of nearly all markers. The proliferative activity in the UPC, PC and OC, and the pro-inflammatory activity in UPC and anti-apoptotic activity in the PC, were correlated with prognosis. Also, two gradients of proliferative activity and a gradient of pro-inflammatory activity were associated with risk of adverse events.

T cell subsets and functions in atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall and the primary underlying cause of cardiovascular disease. Data from in vivo imaging, cell-lineage tracing and knockout studies in mice, as well as clinical interventional studies and advanced mRNA sequencing techniques, have drawn attention to the role of T cells as critical drivers and modifiers of the pathogenesis of atherosclerosis. CD4+ T cells are commonly found in atherosclerotic plaques. A large body of evidence indicates that T helper 1 (TH1) cells have pro-atherogenic roles and regulatory T (Treg) cells have anti-atherogenic roles. However, Treg cells can become pro-atherogenic. The roles in atherosclerosis of other TH cell subsets such as TH2, TH9, TH17, TH22, follicular helper T cells and CD28null T cells, as well as other T cell subsets including CD8+ T cells and γδ T cells, are less well understood. Moreover, some T cells seem to have both pro-atherogenic and anti-atherogenic functions. In this Review, we summarize the knowledge on T cell subsets, their functions in atherosclerosis and the process of T cell homing to atherosclerotic plaques. Much of our understanding of the roles of T cells in atherosclerosis is based on findings from experimental models. Translating these findings into human disease is challenging but much needed. T cells and their specific cytokines are attractive targets for developing new preventive and therapeutic approaches including potential T cell-related therapies for atherosclerosis.

Beyond HIV infection: Neglected and varied impacts of CCR5 and CCR5Δ32 on viral diseases

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CCR5 regulates multiple cell types (e.g., T regulatory and Natural Killer cells) and immune responses.

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The effects of CCR5, CCR5Δ32 (variant associated with reduced CCR5 expression) and CCR5 antagonists vary between infections.

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CCR5 affects the pathogenesis of flaviviruses, especially in the brain.

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The genetic variant CCR5Δ32 increases the risk of symptomatic West Nile virus infection.

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The triad “CCR5, extracellular vesicles and infections” is an emerging topic.

The interactions between chemokine receptors and their ligands may affect susceptibility to infectious diseases as well as their clinical manifestations. These interactions mediate both the traffic of inflammatory cells and virus-associated immune responses. In the context of viral infections, the human C-C chemokine receptor type 5 (CCR5) receives great attention from the scientific community due to its role as an HIV-1 co-receptor. The genetic variant CCR5Δ32 (32 base-pair deletion in CCR5 gene) impairs CCR5 expression on the cell surface and is associated with protection against HIV infection in homozygous individuals. Also, the genetic variant CCR5Δ32 modifies the CCR5-mediated inflammatory responses in various conditions, such as inflammatory and infectious diseases. CCR5 antagonists mimic, at least in part, the natural effects of the CCR5Δ32 in humans, which explains the growing interest in the potential benefits of using CCR5 modulators for the treatment of different diseases. Nevertheless, beyond HIV infection, understanding the effects of the CCR5Δ32 variant in multiple viral infections is essential to shed light on the potential effects of the CCR5 modulators from a broader perspective. In this context, this review discusses the involvement of CCR5 and the effects of the CCR5Δ32 in human infections caused by the following pathogens: West Nile virus, Influenza virus, Human papillomavirus, Hepatitis B virus, Hepatitis C virus, Poliovirus, Dengue virus, Human cytomegalovirus, Crimean-Congo hemorrhagic fever virus, Enterovirus, Japanese encephalitis virus, and Hantavirus. Subsequently, this review addresses the impacts of CCR5 gene editing and CCR5 modulation on health and viral diseases. Also, this article connects recent findings regarding extracellular vesicles (e.g., exosomes), viruses, and CCR5. Neglected and emerging topics in “CCR5 research” are briefly described, with focus on Rocio virus, Zika virus, Epstein-Barr virus, and Rhinovirus. Finally, the potential influence of CCR5 on the immune responses to coronaviruses is discussed.

Efferocytosis and Its Associated Cytokines: A Light on Non-tumor and Tumor Diseases?

Billions of cells undergo turnover and die via apoptosis throughout our lifetime. A prompt clearance of these apoptotic cells and debris by phagocytic cells, a process known as efferocytosis, is important in maintaining tissue homeostasis. Accordingly, impaired efferocytosis due to the defective clearance and disrupted stages can lead to a growing number of inflammation- and immune-related diseases. Although numerous studies have shown the mechanisms of efferocytosis, its role in disorders, such as non-tumor and tumor diseases, remains poorly understood. This review summarizes the processes and signal molecules in efferocytosis, and efferocytosis-related functions in non-tumor (e.g., atherosclerosis, lung diseases) and tumor diseases (e.g., breast cancer, prostate cancer), as well as describes the role of involved cytokines. Of note, there is a dual role of efferocytosis in the abovementioned disorders, and a paradoxical effect among non-tumor and tumor diseases in terms of inflammation resolution, immune response, and disease progression. Briefly, intact efferocytosis and cytokines promote tissue repair, while they contribute to tumor progression via the tumor microenvironment and macrophage politzerization. Additionally, this review provides potential targets associated with TAM (TYRO3, AXL, MERTK) receptors and cytokines, such as tumor necrosis factor α and CXCL5, suggesting potential novel therapeutic ways in treating diseases.

Chemokine Receptor 5, a Double-Edged Sword in Metabolic Syndrome and Cardiovascular Disease

The key characteristic of cardiovascular disease (CVD) is endothelial dysfunction, which is likely the consequence of inflammation. It is well demonstrated that chemokines and their receptors play a crucial role in regulating inflammatory responses, and recently, much attention has been paid to chemokine receptor 5 (CCR5) and its ligands. For example, CCR5 aggravates the inflammatory response in adipose tissue by regulating macrophage recruitment and M1/M2 phenotype switch, thus causing insulin resistance and obesity. Inhibition of CCR5 expression reduces the aggregation of pro-atherogenic cytokines to the site of arterial injury. However, targeting CCR5 is not always effective, and emerging evidence has shown that CCR5 facilitates progenitor cell recruitment and promotes vascular endothelial cell repair. In this paper, we provide recent insights into the role of CCR5 and its ligands in metabolic syndrome as related to cardiovascular disease and the opportunities and roadblocks in targeting CCR5 and its ligands.

Current and novel radiopharmaceuticals for imaging cardiovascular inflammation

Cardiovascular disease (CVD) remains the leading cause of death worldwide despite advances in diagnostic technologies and treatment strategies. The underlying cause of most CVD is atherosclerosis, a chronic disease driven by inflammatory reactions. Atherosclerotic plaque rupture could cause arterial occlusion leading to ischemic tissue injuries such as myocardial infarction (MI) and stroke. Clinically, most imaging modalities are based on anatomy and provide limited information about the on-going molecular activities affecting the vulnerability of atherosclerotic lesion for risk stratification of patients. Thus, the ability to differentiate stable plaques from those that are vulnerable is an unmet clinical need. Of various imaging techniques, the radionuclide-based molecular imaging modalities including positron emission tomography and single-photon emission computerized tomography provide superior ability to noninvasively visualize molecular activities in vivo and may serve as a useful tool in tackling this challenge. Moreover, the well-established translational pathway of radiopharmaceuticals may also facilitate the translation of discoveries from benchtop to clinical investigation in contrast to other imaging modalities to fulfill the goal of precision medicine. The relationship between inflammation occurring within the plaque and its proneness to rupture has been well documented. Therefore, an active effort has been significantly devoted to develop radiopharmaceuticals specifically to measure CVD inflammatory status, and potentially elucidate those plaques which are prone to rupture. In the following review, molecular imaging of inflammatory biomarkers will be briefly discussed.

Immunobiology of Atherosclerosis: A Complex Net of Interactions

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

G-Protein Coupled Receptor Targeting on Myeloid Cells in Atherosclerosis

Atherosclerosis, the underlying cause of the majority of cardiovascular diseases (CVDs), is a lipid-driven, inflammatory disease of the large arteries. Gold standard therapy with statins and the more recently developed proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have improved health conditions among CVD patients by lowering low density lipoprotein (LDL) cholesterol. Nevertheless, a substantial part of these patients is still suffering and it seems that 'just' lipid lowering is insufficient. The results of the Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) have now proven that inflammation is a key driver of atherosclerosis and that targeting inflammation improves CVD outcomes. Therefore, the identification of novel drug targets and development of novel therapeutics that block atherosclerosis-specific inflammatory pathways have to be promoted. The inflammatory processes in atherosclerosis are facilitated by a network of immune cells and their subsequent responses. Cell networking is orchestrated by various (inflammatory) mediators which interact, bind and induce signaling. Over the last years, G-protein coupled receptors (GPCRs) emerged as important players in recognizing these mediators, because of their diverse functions in steady state but also and specifically during chronic inflammatory processes - such as atherosclerosis. In this review, we will therefore highlight a selection of these receptors or receptor sub-families mainly expressed on myeloid cells and their role in atherosclerosis. More specifically, we will focus on chemokine receptors, both classical and atypical, formyl-peptide receptors, the chemerin receptor 23 and the calcium-sensing receptor. When information is available, we will also describe the consequences of their targeting which may hold promising options for future treatment of CVD.

CD146 deficiency promotes plaque formation in a mouse model of atherosclerosis by enhancing RANTES secretion and leukocyte recruitment

AIMS

The progression of atherosclerosis is based on the continued recruitment of leukocytes in the vessel wall. The previously described role of CD146 in leukocyte infiltration suggests an involvement for this adhesion molecule in the inflammatory response. In this study, we investigated the role of CD146 in leukocyte recruitment by using an experimental model of atherogenesis.

METHODS AND RESULTS

The role of CD146 was explored in atherosclerosis by crossing CD146-/- mice with ApoE-/- mice. CD146 -/-/ApoE -/- and ApoE -/- mice were fed a Western diet for 24 weeks and were monitored for aortic wall thickness using high frequency ultrasound. The arterial wall was significantly thicker in CD146-deficient mice. After 24 weeks of Western diet, a significant increase of atheroma in both total aortic lesion and aortic sinus of CD146-null mice was observed. In addition, atherosclerotic lesions were more inflammatory since plaques from CD146-deficient mice contained more neutrophils and macrophages. This was due to up-regulation of RANTES secretion by macrophages in CD146-deficient atherosclerotic arteries. This prompted us to further address the function of CD146 in leukocyte recruitment during acute inflammation by using a second experimental model of peritonitis induced by thioglycollate. Neutrophil recruitment was significantly increased in CD146-deficient mice 12 h after peritonitis induction and associated with higher RANTES levels in the peritoneal cavity. In CD146-null macrophages, we also showed that increased RANTES production was dependent on constitutive inhibition of the p38-MAPK signaling pathway. Finally, Maraviroc, a RANTES receptor antagonist, was able to reduce atherosclerotic lesions and neutrophilia in CD146-deficient mice to the same level as that found in ApoE -/- mice.

CONCLUSIONS

Our data indicate that CD146 deficiency is associated with the upregulation of RANTES production and increased inflammation of atheroma, which could influence the atherosclerotic plaque fate. Thus, these data identify CD146 agonists as potential new therapeutic candidates for atherosclerosis treatment.

Therapeutic Approaches Targeting Inflammation in Cardiovascular Disorders

Cardiovascular disease is a leading cause of morbidity and mortality in the Western world and represents an enormous global health burden. Significant advances have been made in the conservative, medical and surgical management across the range of cardiovascular diseases however the inflammatory components of these diseases have traditionally been neglected. Inflammation is certainly a key component of atherosclerosis, a chronic inflammatory condition, but it is at least correlative and predictive of risk in many other aspects of cardiovascular medicine ranging from heart failure to outcomes following reperfusion strategies. Inflammation therefore represents significant potential for future risk stratification of patients as well as offering new therapeutic targets across cardiovascular medicine. This review explores the role of inflammation in several of the major aspects of cardiovascular medicine focusing on current and possible future examples of the targeting of inflammation in prognosis and therapy. It concludes that future directions of cardiovascular research and clinical practice should seek to identify cohorts of patients with a significant inflammatory component to their cardiovascular condition or reaction to cardiovascular intervention. These patients might benefit from therapeutic strategies mounted against the inflammatory components implicated in their condition.