Macrophages regulate vascular smooth muscle cell function during atherosclerosis progression through IL-1β/STAT3 signaling

Importance of STAT3 signaling in preeclampsia (Review)

Placentation is a key process that is tightly regulated that ensures the normal placenta and fetal development. Preeclampsia (PE) is a hypertensive pregnancy‑associated disorder characterized by increased oxidative stress and inflammation. STAT3 signaling plays a key role in modulating important processes such as cell proliferation, differentiation, invasion and apoptosis. The present review aimed to analyse the role of STAT3 signaling in PE pregnancies, discuss the main natural and synthetic compounds involved in modulation of this signaling both in vivo and in vitro and summarize the main cellular modulators of this signaling to identify possible therapeutic targets and treatments to improve the outcome of PE pregnancies.

Identification of potential biomarkers in cardiovascular calcification based on bioinformatics combined with single-cell RNA-seq and multiple machine learning analysis

BACKGROUND

The molecular and genetic mechanisms underlying vascular calcification remain unclear. This study aimed to determine the differences in calcification marker-related gene expression in macrophages.

METHODS

The expression profiling datasets GSE104140 and GSE235995 were analysed to identify differentially expressed genes (DEGs) between fibroatheroma with calcification and diffuse intimal thickening. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, Weighted Gene Co-expression Network Analysis (WGCNA), and Gene Set Enrichment Analysis (GSEA) were performed to assess functional characteristics. Hub genes were identified through a protein-protein interaction (PPI) network and machine learning approaches. Single-cell RNA sequencing data (GSE159677) validated the expression of calcification-related genes in macrophages, while Mendelian randomization analysis explored their potential causal relationship with coronary calcification. Further validation was conducted using enzyme-linked immunosorbent assay (ELISA) on coronary calcification samples and immunohistochemistry in ApoE-/- mice. Intravascular ultrasound was performed to assess coronary calcification severity.

RESULTS AND CONCLUSIONS

Two key biomarkers, ITGAX and MYD88, were identified as diagnostic indicators of cardiovascular calcification. Both biomarkers were significantly upregulated in calcified samples and were strongly associated with immune processes. Single-cell RNA sequencing confirmed their high expression in multiple immune cell types. Additionally, molecular docking analysis revealed that retinoic acid interacted with both biomarkers, suggesting potential therapeutic relevance. Immunohistochemical and ELISA analyses further validated their elevated expression in calcified samples. These findings provide novel insights into the molecular mechanisms of vascular calcification and highlight potential diagnostic and therapeutic targets.

Macrophage pyroptosis in atherosclerosis: therapeutic potential

Atherosclerosis (AS) is a chronic inflammatory disease characterized by the accumulation of lipid-rich plaques in arterial walls, leading to cardiovascular events such as myocardial infarction and stroke. Macrophage pyroptosis, a form of programmed cell death driven by the NLRP3 inflammasome and caspase-1 activation, plays a critical role in the progression and destabilization of atherosclerotic plaques. This review explores the molecular mechanisms underlying macrophage pyroptosis and their significant contributions to AS pathogenesis. Recent advancements have highlighted the therapeutic potential of targeting key components of the pyroptotic pathway, including the use of nanotechnology to increase drug delivery specificity. These strategies are promising for reducing inflammation, stabilizing plaques, and mitigating the clinical impact of AS. Future studies should focus on translating these findings into clinical applications to develop effective treatments that can halt or reverse AS progression by modulating macrophage pyroptosis.

Single-cell and spatial analysis reveals the interaction between ITLN1+ foam cells and SPP1+ macrophages in atherosclerosis

Introduction

Cardiovascular disease (CVD) caused by atherosclerosis (AS) remains the leading cause of mortality in developed countries. Understanding cellular heterogeneity within the inflammatory microenvironment is crucial for advancing disease management strategies. This study investigates the regulatory functions of distinct cell populations in AS pathogenesis, focusing on the interaction between vascular smooth muscle cell (VSMC)-derived ITLN1+ foam cells and SPP1+ FABP5+ macrophages.

Methods

We employed single-cell RNA sequencing to characterize cell populations within AS plaques. Correlation analyses and the CellChat package were utilized to elucidate intercellular communication networks among various cell types. The functional roles of key subsets of macrophages and VSMCs were assessed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Pseudotime trajectory analysis was conducted to explore the dynamics of VSMC differentiation. Additionally, spatial transcriptomics analysis was used to demonstrate the physical interactions between different cell subpopulations.

Results

We identified significant infiltration of macrophage clusters in AS, with SPP1+ FABP5+ macrophages being highly enriched in AS plaques. These macrophages were associated with lipid transport, storage, and cell migration pathways. A distinct subset of ITLN1+ foam cells derived from VSMCs exhibited robust expression of foam cell markers and lipid metabolism-related genes. Pseudotime trajectory analysis indicated that ITLN1+ foam cells represent a terminal stage of VSMC differentiation, characterized by elevated expression of genes linked to lipid synthesis and AS progression. Spatial transcriptomics and CellChat analysis revealed a significant interaction between ITLN1+ foam cells and SPP1+ FABP5+ macrophages, mediated by the MIF-(CD74 + CD44) and SPP1-CD44 ligand-receptor axes.

Discussion

Our findings underscore the critical crosstalk between ITLN1+ foam cells and SPP1+ macrophages in promoting lipid accumulation and AS progression. Targeting this cell-cell interaction may offer new therapeutic avenues for managing atherosclerosis. Further validation of these mechanisms is necessary to develop effective immunotherapeutic strategies against AS.

Ginsenoside Rb1 inhibits porcine epidemic diarrhea virus replication through suppressing S1 protein mediated the MAPK/ERK pathway and reducing apoptosis

Porcine epidemic diarrhea virus (PEDV) causes vomiting, dehydration, and diarrhea in piglets, seriously threatening their survival and development and causing huge economic losses to the global pig industry. Current PEDV control relies on vaccines, however, the high mutation rate of PEDV limits vaccine effectiveness, highlighting the need for new antiviral drugs. This study investigated the pharmacological effects of ginsenoside Rb1 (GRb1) on PEDV using network pharmacology, as well as GO and KEGG analyses, to predict its role in modulating the MAPK/ERK pathway. GRb1 downregulated the MAPK/ERK pathway activated by PEDV infection and reduced levels of the apoptotic protein cleaved-caspase-3, thus inhibiting PEDV-induced apoptosis and demonstrating antiviral properties. Further screening showed that the PEDV S1 protein promotes AP-1 nuclear entry and upregulates the MAPK/ERK pathway to induce apoptosis, a process reversed by GRb1. Further in vivo studies revealed that GRb1 treatment significantly reduced viral load in piglet intestinal tissues and anal swabs. GRb1 also alleviated clinical symptoms and intestinal damage in infected piglets, improving their survival rate while also downregulating the levels of inflammatory factors (IL-1β, IL-6, IL-8, and TNF-α). This study is the first to demonstrate that GRb1 effectively inhibits PEDV, uncovering its potential mechanism of action and providing a promising new approach for antiviral treatment in veterinary medicine.

Epigenetic regulation of vascular smooth muscle cell phenotypes in atherosclerosis

Vascular smooth muscle cells (VSMCs) in adult arteries maintain substantial phenotypic plasticity, which allows for the reversible cell state changes that enable vascular remodelling and homeostasis. In atherosclerosis, VSMCs dedifferentiate in response to lipid accumulation and inflammation, resulting in loss of their characteristic contractile state. Recent studies showed that individual, pre-existing VSMCs expand clonally and can acquire many different phenotypes in atherosclerotic lesions. The changes in gene expression underlying this phenotypic diversity are mediated by epigenetic modifications which affect transcription factor access and thereby gene expression dynamics. Additionally, epigenetic mechanisms can maintain cellular memory, potentially facilitating reversion to the contractile state. While technological advances have provided some insight, a comprehensive understanding of how VSMC phenotypes are governed in disease remains elusive. Here we review current literature in light of novel insight from studies at single-cell resolution. We also discuss how lessons from epigenetic studies of cellular regulation in other fields could help in translating the potential of targeting VSMC phenotype conversion into novel therapies in cardiovascular disease.

Dedifferentiation of vascular smooth muscle cells upon vessel injury

Highly differentiated mature vascular smooth muscle cells (VSMCs) are the predominant type of cells constituting arterial walls, which are essential for maintaining the structural and functional integrity of blood vessels. VSMCs demonstrate a notable degree of adaptability following vascular damage, a characteristic that plays a crucial role in the progression of vascular remodeling. Advances in single-cell RNA sequencing in both healthy and pathological vascular tissues have offered profound insights into the complexity of VSMCs, revealing a more intricate diversity than previously recognized. In response to injury, VSMCs undergo dedifferentiation and exhibit pluripotent markers. This review summarizes the researches that have employed lineage tracing alongside single-cell sequencing analysis to explore the dynamics of vascular damage. The primary focus of this study was on the process of dedifferentiation in VSMCs, with particular attention to its underlying mechanisms. The discussion included the impact of microenvironmental cues, the control of transcription factors, and the various molecular pathways involved in VSMCs dedifferentiation. Herein, we provide a comprehensive analysis of cells dedifferentiated from adult VSMCs upon vascular injury.

Vascular smooth muscle cell phenotypic switching in atherosclerosis

Atherosclerosis (AS) is a complex pathology process involving intricate interactions among various cells and biological processes. Vascular smooth muscle cells (VSMCs) are the predominant cell type in normal arteries, and under atherosclerotic stimuli, VSMCs respond to altered blood flow and microenvironment changes by downregulating contractile markers and switching their phenotype. This review overviews the diverse phenotypes of VSMCs, including the canonical contractile VSMCs, synthetic VSMCs, and phenotypes resembling macrophages, foam cells, myofibroblasts, osteoblasts/chondrocytes, and mesenchymal stem cells. We summarize their presumed protective and pro-atherosclerotic roles in AS development. Additionally, we underscore the molecular mechanisms and regulatory pathways governing VSMC phenotypic switching, encompassing transcriptional regulation, biochemical factors, plaque microenvironment, epigenetics, miRNAs, and the cytoskeleton, emphasizing their significance in AS development. Finally, we outline probable future research directions targeting VSMCs, offering insights into potential therapeutic strategies for AS management.

8-Aminoguanine and its actions in the metabolic syndrome

The metabolic syndrome is characterized by obesity, insulin resistance, dyslipidemia and hypertension and predisposes to cardiorenal injury. Here, we tested our hypothesis that 8-aminoguanine, an endogenous purine, exerts beneficial effects in Zucker Diabetic-Sprague Dawley (ZDSD) rats, a preclinical model of the metabolic syndrome. ZDSD rats were instrumented for blood pressure radiotelemetry and randomized to vehicle or 8-aminoguanine (10 mg/kg/day, po). The protocol was divided into four phases: Phase 1: 17 days of tap water/normal diet; Phase 2: 30 days of 1% saline/normal diet; Phase 3: 28 days of 1% saline/diabetogenic diet; Phase 4: acute/terminal measurements. 8-Aminoguanine: (1) decreased mean arterial blood pressure (P = 0.0004; 119.5 ± 1.0 (vehicle) versus 116.3 ± 1.0 (treated) mmHg) throughout all three phases of the radiotelemetry study; (2) rebalanced the purine metabolome away from hypoxanthine (pro-inflammatory) and towards inosine (anti-inflammatory); (3) reduced by 71% circulating IL-1β, a cytokine that contributes to hypertension-induced adverse cardiovascular events and type 2 diabetes; (4) attenuated renovascular responses to angiotensin II; (5) improved cardiac and renal histopathology; (6) attenuated diet-induced polydipsia/polyuria; and (7) reduced HbA1c. In the metabolic syndrome, 8-aminoguanine lowers blood pressure, improves diabetes and reduces organ damage, likely by rebalancing the purine metabolome leading to reductions in injurious cytokines such as IL-1β.

Immune and inflammatory insights in atherosclerosis: development of a risk prediction model through single-cell and bulk transcriptomic analyses

Background

Investigation into the immune heterogeneity linked with atherosclerosis remains understudied. This knowledge gap hinders the creation of a robust theoretical framework essential for devising personalized immunotherapies aimed at combating this disease.

Methods

Single-cell RNA sequencing (scRNA-seq) analysis was employed to delineate the immune cell-type landscape within atherosclerotic plaques, followed by assessments of cell-cell interactions and phenotype characteristics using scRNA-seq datasets. Subsequently, pseudotime trajectory analysis was utilized to elucidate the heterogeneity in cell fate and differentiation among macrophages. Through integrated approaches, including single-cell sequencing, Weighted Gene Co-expression Network Analysis (WGCNA), and machine learning techniques, we identified hallmark genes. A risk score model and a corresponding nomogram were developed and validated using these genes, confirmed through Receiver Operating Characteristic (ROC) curve analysis. Additionally, enrichment and immune characteristic analyses were conducted based on the risk score model. The model's applicability was further corroborated by in vitro and in vivo validation of specific genes implicated in atherosclerosis.

Result

This comprehensive scRNA-seq analysis has shed new light on the intricate immune landscape and the role of macrophages in atherosclerotic plaques. The presence of diverse immune cell populations, with a particularly enriched macrophage population, was highlighted by the results. Macrophage heterogeneity was intricately characterized, revealing four distinct subtypes with varying functional attributes that underscore their complex roles in atherosclerotic pathology. Intercellular communication analysis revealed robust macrophage interactions with multiple cell types and detailed pathways differing between proximal adjacent and atherosclerotic core groups. Furthermore, pseudotime trajectories charted the developmental course of macrophage subpopulations, offering insights into their differentiation fates within the plaque microenvironment. The use of machine learning identified potential diagnostic markers, culminating in the identification of RNASE1 and CD14. The risk score model based on these biomarkers exhibited high accuracy in diagnosing atherosclerosis. Immune characteristic analysis validated the risk score model's efficacy in defining patient profiles, distinguishing high-risk individuals with pronounced immune cell activities. Finally, experimental validation affirmed RNASE1's involvement in atherosclerotic progression, suggesting its potential as a therapeutic target.

Conclusion

Our findings have advanced our understanding of atherosclerosis immunopathology and paved the way for novel diagnostic and therapeutic strategies.

ASIC1/RIP1 accelerates atherosclerosis via disrupting lipophagy

INTRODUCTION

Atherosclerosis, a major contributor to cardiovascular disease, remains a significant health concern worldwide. While previous research has shown that acid-sensing ion channel 1 (ASIC1) impedes macrophage cholesterol efflux, its precise role in atherogenesis and the underlying mechanisms have remained elusive.

OBJECTIVES

This study aimed to investigate the role of ASIC1 in atherosclerosis and its underlying mechanisms.

METHODS

First, data from a single-cell RNA sequencing (scRNA-seq) database were used to explore the relationships between ASIC1 differential expression and lipophagy in human atherosclerotic lesions. Finally, we validated the role of ASIC1/RIP1 signaling in lipophagy in vivo (human and mice) and in vitro (RAW264.7 and HTP-1 cells).

RESULT

Our results demonstrated a significant increase in ASIC1 protein levels within CD68+ macrophages in both human aortic lesions and AopE-/- mouse lesion areas compared to nonlesion regions. Concurrently, there was a notable decrease in lipophagy, a crucial process for lipid metabolism. In vitro assays further elucidated that ASIC1 interaction with RIP1 (receptor-interacting protein 1) promoted the phosphorylation of RIP1 at serine 166 and transcription factor EB (TFEB) at serine 142, leading to disrupted lipophagy and increased lipid accumulation. Intriguingly, all these events were reversed upon ASIC1 deficiency and RIP1 inhibition. Furthermore, in ApoE-/- mouse models of atherosclerosis, silencing ASIC1 expression or inhibiting RIP1 activation not only significantly attenuated atherogenesis but also restored TFEB-mediated lipophagy in aortic tissues. This was evidenced by reduced TFEB Ser-142 phosphorylation, decreased LC3II and LAMP1 protein expression, increased numbers of lipophagosomes, and a decrease in lipid droplets.

CONCLUSION

Our findings unveil the critical role of macrophage ASIC1 in interacting with RIP1 to inhibit lipophagy, thereby promoting atherogenesis. Targeting ASIC1 represents a promising therapeutic avenue for the treatment of atherosclerosis.

Macrophages in vascular disease: Roles of mitochondria and metabolic mechanisms

Macrophages are a dynamic cell type of the immune system implicated in the pathophysiology of vascular diseases and are a major contributor to pathological inflammation. Excessive macrophage accumulation, activation, and polarization is observed in aortic aneurysm (AA), atherosclerosis, and pulmonary arterial hypertension. In general, macrophages become activated and polarized to a pro-inflammatory phenotype, which dramatically changes cell behavior to become pro-inflammatory and infiltrative. These cell types become cumbersome and fail to be cleared by normal mechanisms such as autophagy. The result is a hyper-inflammatory environment causing the recruitment of adjacent cells and circulating immune cells to further augment the inflammatory response. In AA, this leads to excessive ECM degradation and chemokine secretion, ultimately causing macrophages to dominate the immune cell landscape in the aortic wall. In atherosclerosis, monocytes are recruited to the vascular wall, where they polarize to the pro-inflammatory phenotype and induce inflammatory pathway activation. This leads to the development of foam cells, which significantly contribute to neointima and necrotic core formation in atherosclerotic plaques. Pro-inflammatory macrophages, which affect other vascular diseases, present with fragmented mitochondria and corresponding metabolic dysfunction. Targeting macrophage mitochondrial dynamics has proved to be an exciting potential therapeutic approach to combat vascular disease. This review will summarize mitochondrial and metabolic mechanisms of macrophage activation, polarization, and accumulation in vascular diseases.

Quercetin Attenuates KLF4-Mediated Phenotypic Switch of VSMCs to Macrophage-like Cells in Atherosclerosis: A Critical Role for the JAK2/STAT3 Pathway

The objective of this study was to elucidate the protective role of quercetin in atherosclerosis by examining its effect on the phenotypic switch of vascular smooth muscle cells (VSMCs) to macrophage-like cells and the underlying regulatory pathways. Aorta tissues from apolipoprotein E-deficient (ApoE KO) mice fed a high-fat diet (HFD), treated with or without 100 mg/kg/day quercetin, were analyzed for histopathological changes and molecular mechanisms. Quercetin was found to decrease the size of atherosclerotic lesions and mitigate lipid accumulation induced by HFD. Fluorescence co-localization analysis revealed a higher presence of macrophage-like vascular smooth muscle cells (VSMCs) co-localizing with phospho-Janus kinase 2 (p-JAK2), phospho-signal transducer and activator of transcription 3 (p-STAT3), and Krüppel-like factor 4 (KLF4) in regions of foam cell aggregation within aortic plaques. However, this co-localization was reduced following treatment with quercetin. Quercetin treatment effectively inhibited the KLF4-mediated phenotypic switch in oxidized low-density lipoprotein (ox-LDL)-loaded mouse aortic vascular smooth muscle cells (MOVAS), as indicated by decreased expressions of KLF4, LGALS3, CD68, and F4/80, increased expression of alpha smooth muscle actin (α-SMA), reduced intracellular fluorescence Dil-ox-LDL uptake, and decreased lipid accumulation. In contrast, APTO-253, a KLF4 activator, was found to reverse the effects of quercetin. Furthermore, AG490, a JAK2 inhibitor, effectively counteracted the ox-LDL-induced JAK2/STAT3 pathway-dependent switch to a macrophage-like phenotype and lipid accumulation in MOVAS cells. These effects were significantly mitigated by quercetin but exacerbated by coumermycin A1, a JAK2 activator. Our research illustrates that quercetin inhibits the KLF4-mediated phenotypic switch of VSMCs to macrophage-like cells and reduces atherosclerosis by suppressing the JAK2/STAT3 pathway.

Multiplex Imaging for Cell Phenotyping of Early Human Atherosclerosis

BACKGROUND

Previous studies using animal models and cultured cells suggest that vascular smooth muscle cells (SMCs) and inflammatory cytokines are important players in atherogenesis. Validating these findings in human disease is critical to designing therapeutics that target these components. Multiplex imaging is a powerful tool for characterizing cell phenotypes and microenvironments using biobanked human tissue sections. However, this technology has not been applied to human atherosclerotic lesions and needs to first be customized and validated.

METHODS AND RESULTS

For validation, we created an 8-plex imaging panel to distinguish foam cells from SMC and leukocyte origins on tissue sections of early human atherosclerotic lesions (n=9). The spatial distribution and characteristics of these foam cells were further analyzed to test the association between SMC phenotypes and inflammation. Consistent with previous reports using human lesions, multiplex imaging showed that foam cells of SMC origin outnumbered those of leukocyte origin and were enriched in the deep intima, where the lipids accumulate in early atherogenesis. This new technology also found that apoptosis or the expression of pro-inflammatory cytokines were not more associated with foam cells than with nonfoam cells in early human lesions. More CD68+ SMCs were present among SMCs that highly expressed interleukin-1β. Highly inflamed SMCs showed a trend of increased apoptosis, whereas leukocytes expressing similar levels of cytokines were enriched in regions of extracellular matrix remodeling.

CONCLUSIONS

The multiplex imaging method can be applied to biobanked human tissue sections to enable proof-of-concept studies and validate theories based on animal models and cultured cells.

Network-based prioritization and validation of regulators of vascular smooth muscle cell proliferation in disease

Aberrant vascular smooth muscle cell (VSMC) homeostasis and proliferation characterize vascular diseases causing heart attack and stroke. Here we elucidate molecular determinants governing VSMC proliferation by reconstructing gene regulatory networks from single-cell transcriptomics and epigenetic profiling. We detect widespread activation of enhancers at disease-relevant loci in proliferation-predisposed VSMCs. We compared gene regulatory network rewiring between injury-responsive and nonresponsive VSMCs, which suggested shared transcription factors but differing target loci between VSMC states. Through in silico perturbation analysis, we identified and prioritized previously unrecognized regulators of proliferation, including RUNX1 and TIMP1. Moreover, we showed that the pioneer transcription factor RUNX1 increased VSMC responsiveness and that TIMP1 feeds back to promote VSMC proliferation through CD74-mediated STAT3 signaling. Both RUNX1 and the TIMP1-CD74 axis were expressed in human VSMCs, showing low levels in normal arteries and increased expression in disease, suggesting clinical relevance and potential as vascular disease targets.

KLF13 promotes VSMCs phenotypic dedifferentiation by directly binding to the SM22α promoter

Krüppel-like factor 13 (KLF13), a zinc finger transcription factor, is considered as a potential regulator of cardiomyocyte differentiation and proliferation during heart morphogenesis. However, its precise role in the dedifferentiation of vascular smooth muscle cells (VSMCs) during atherosclerosis and neointimal formation after injury remains poorly understood. In this study, we investigated the relationship between KLF13 and SM22α expression in normal and atherosclerotic plaques by bioanalysis, and observed a significant increase in KLF13 levels in the atherosclerotic plaques of both human patients and ApoE-/- mice. Knockdown of KLF13 was found to ameliorate intimal hyperplasia following carotid artery injury. Furthermore, we discovered that KLF13 directly binds to the SM22α promoter, leading to the phenotypic dedifferentiation of VSMCs. Remarkably, we observed a significant inhibition of platelet-derived growth factor BB-induced VSMCs dedifferentiation, proliferation, and migration when knocked down KLF13 in VSMCs. This inhibitory effect of KLF13 knockdown on VCMC function was, at least in part, mediated by the inactivation of p-AKT signaling in VSMCs. Overall, our findings shed light on a potential therapeutic target for treating atherosclerotic lesions and restenosis after vascular injury.

Liraglutide attenuates angiotensin II-induced aortic dissection and aortic aneurysm via inhibiting M1 macrophage polarization in APOE -/- mice

BACKGROUND

Aortic Aneurysm and Dissection (AAD) are severe cardiovascular conditions with potentially lethal consequences such as aortic rupture. Existing studies suggest that liraglutide, a long-acting glucagon-like peptide receptor (GLP-1R) agonist, offers protective benefits across various cardiovascular diseases. However, the efficacy of liraglutide in mitigating AAD development is yet to be definitively elucidated.

METHODS

Ang II (Angiotension II) infusion of APOE-/- mouse model with intraperitoneal injection of liraglutide (200 μg/kg) to study the role of GLP-1R in AAD formation. Bone Marrow Derived Macrophages (BMDM) and Raw264.7 were incubated with LPS, liraglutide, exendin 9-39 or LY294002 alone or in combination. SMC phenotype switching was examined in a macrophage and vascular smooth muscle cell (VSMC) co-culture system. An array of analytical methods, including Western Blot, Immunofluorescence Staining, Enzyme-LinkedImmunosorbent Assay, Real-Time Quantitative Polymerase Chain Reaction, RNA-seq, and so on were employed.

RESULTS

Our investigation revealed a significant increase in M1 macrophage polarization and GLP-1R expression in aortas of AD patients and Ang II-induced AAD APOE-/- mice. Administering liraglutide in APOE-/- mice notably reduced Ang II-induced AAD incidence and mortality. It was found that liraglutide inhibits M1 macrophage polarization primarily via GLP-1R activation, and subsequently modulates vascular smooth muscle cell phenotypic switching was the primary mechanism. RNA-Seq and subsequent KEGG enrichment analysis identified CXCL3, regulated by the PI3K/AKT signaling pathway, as a key element in liraglutide's modulation of M1 macrophage polarization.

CONCLUSION

Our study found liraglutide exhibits protective effects against AAD by modulating M1 macrophage polarization, suppressing CXCL3 expression through the PI3K/AKT signaling pathway. This makes it a promising therapeutic target for AAD, offering a new avenue in AAD management.

Macrophage-mediated downregulation of lncRNA Carmn in mouse abdominal aortic aneurysm

The long noncoding RNA (lncRNA) CARMN (cardiac mesoderm enhancer associated noncoding RNA) is a highly conserved lncRNA that expresses primarily by smooth muscle cells (SMCs). Recent literature demonstrates that CARMN plays a critical role in the differentiation and maintaining of the contractile state of vascular SMCs. Because aortic SMCs show diminished contractile proteins in abdominal aortic aneurysms (AAAs), we hypothesize that the expression of CARMN is downregulated in the aortic wall affected by aneurysm. In this study, we analyzed publicly available single-cell or bulk RNA sequencing data comparing healthy and aneurysmal mouse aortic tissues. In both healthy and diseased aortas, Carmn expression was enriched in SMCs characterized by the high expression of SMC-specific contractile proteins including Myh11 and Acta2. Carmn expression levels varied among the sub-clusters of SMCs and consequently along the aortic tree. Comparing to the corresponding sham aorta, aortas from 3 distinct AAA models contained less Carmn. To validate the Carmn downregulation, we induced AAA using the Angiotensin II and CaCl2 models. In situ hybridization showed that Carmn mRNA located in the nuclei of SMCs and became downregulated within a few days following the aneurysm induction. Mechanistically, we tested whether Carmn expression is regulated by infiltrating macrophages --- the predominant inflammatory cells found in aneurysmal tissues --- by treating healthy mouse aortic SMCs with media conditioned by macrophages primed with pro-inflammatory or anti-inflammatory cytokines. PCR analysis showed that inflammatory macrophages reduced the expression of Carmn and contractile genes including Myh11 and Acta2. Taken together, our results from bioinformatic and experimental analyses demonstrate that Carmn is downregulated in different AAA models, likely by inflammatory macrophages. The negative regulation of Carmn in AAA tissues may explain at least in part the loss of SMC contractile state during the pathogenesis of this progressive degenerative disease.

The lncRNA GAS5 upregulates ANXA2 to mediate the macrophage inflammatory response during atherosclerosis development

Inflammatory macrophages play a crucial role in atherosclerosis development. The long non-coding RNA growth arrest-specific 5 (GAS5) regulates THP-1 macrophage inflammation by sponging microRNAs. The purpose of this study was to investigate the regulatory mechanism of GAS5 in atherosclerosis development. GSE40231, GSE21545, and GSE28829 datasets from the Gene Expression Omnibus database were integrated after adjusting for batch effect. Differential analysis was performed on the integrated dataset and validated using the Genotype-Tissue Expression and GSE57691 datasets. Potential biological functions of GAS5 and annexin A2 (ANXA2) were identified using gene set enrichment analysis (GSEA). ssGSEA, CIBERSORTx, and ImmuCellAI algorithms were used to identify immune infiltration in plaque samples. GAS5 and ANXA2 expression levels in RAW264.7 cells treated with oxidized low-density lipoprotein (ox-LDL) were measured by qRT-PCR and Western blot. Small interfering and short hairpin RNA were used to silence GAS5 expression. Plasmids of ANXA2 were used to establish ANXA2 overexpression. Apoptosis and inflammatory markers in macrophages were detected by Western blot. Aortic samples from APOE-/- mice were collected to validate the expression of GAS5 and ANXA2. GAS5 expression was significantly increased during atherosclerosis. GAS5 expression was positively correlated with macrophage activation and ANXA2 expression in plaques. Furthermore, ANXA2 upregulation was also related to the activation of macrophage. GSEA indicated similar biological functions for GAS5 and ANXA2 in plaques. Moreover, in vitro experiments showed that both GAS5 and ANXA2 contributed to macrophage apoptosis and inflammation. Rescue assays revealed that the inflammatory effects of GAS5 on macrophages were ANXA2-dependent. In vivo experiments confirmed the highly expression of Gas5 and Anxa2 in the plaque group. We identified the atherogenic roles of GAS5 and ANXA2 in the inflammatory response of macrophages. The inflammatory response in ox-LDL-treated macrophages was found to be mediated by GAS5-ANXA2 regulation, opening new avenues for atherosclerosis therapy.

Ficolin-2 amplifies inflammation in macrophage-smooth muscle cell cross-talk and increases monocyte transmigration by mechanisms involving IL-1β and IL-6

Ficolin-2, recently identified in atherosclerotic plaques, has been correlated with future acute cardiovascular events, but its role remains unknown. We hypothesize that it could influence plaque vulnerability by interfering in the cross-talk between macrophages (MØ) and smooth muscle cells (SMC). To examine its role and mechanism of action, we exposed an in-vitro co-culture system of SMC and MØ to ficolin-2 (10 µg/mL) and then performed cytokine array, protease array, ELISA, qPCR, Western Blot, and monocyte transmigration assay. Carotid plaque samples from atherosclerotic patients with high plasma levels of ficolin-2 were analyzed by immunofluorescence. We show that ficolin-2: (i) promotes a pro-inflammatory phenotype in SMC following interaction with MØ by elevating the gene expression of MCP-1, upregulating gene and protein expression of IL-6 and TLR4, and by activating ERK/MAPK and NF-KB signaling pathways; (ii) increased IL-1β, IL-6, and MIP-1β in MØ beyond the level induced by cellular interaction with SMC; (iii) elevated the secretion of IL-1β, IL-6, and CCL4 in the conditioned medium; (iv) enhanced monocyte transmigration and (v) in atherosclerotic plaques from patients with high plasma levels of ficolin-2, we observed co-localization of ficolin-2 with SMC marker αSMA and the cytokines IL-1β and IL-6. These findings shed light on previously unknown mechanisms underlying ficolin-2-dependent pathological inflammation in atherosclerotic plaques.

DNA methylation profiling and integrative multi-omics analysis of skin samples reveal important contribution of epigenetics and immune response in the pathogenesis of acne vulgaris

The regulatory effect of DNA methylation on the pathogenesis of acne vulgaris is completely unknown. Herein we analyzed the DNA methylation profile in skin samples of acne vulgaris and further integrated it with gene expression profiles and single-cell RNA-sequencing data. Finally, 31,134 differentially methylated sites and 770 differentially methylated and expressed genes (DMEGs) were identified. The multi-omics analysis suggested the importance of DNA methylation in inflammation and immunity in acne. And DMEGs were verified in an external dataset and were closely related to early inflammatory acne. Additionally, we conducted experiments to verify the mRNA expression and DNA methylation level of DMEGs. This study supports the significant contribution of epigenetics to the pathogenesis of acne vulgaris and may provide new ideas for the molecular mechanisms of and potential therapeutic strategies for acne vulgaris.

Roles of pyroptosis in atherosclerosis pathogenesis

Pyroptosis is a pro-inflammatory type of regulated cell death (RCD) characterized by gasdermin protein-mediated membrane pore formation, cell swelling, and rapid lysis. Recent studies have suggested that pyroptosis is closely related to atherosclerosis (AS). Previous studies reported that pyroptosis involving endothelial cells (ECs), macrophages, and smooth muscle cells (SMCs) plays an important role in the formation and development of AS. Pyroptosis not only causes local inflammation but also amplifies the inflammatory response and it aggravates plaque instability, leading to plaque rupture and thrombosis, eventually resulting in acute cardiovascular events. In this review, we clarified some novel pathways and mechanics and presented some potential drugs.

The Chinese medicine Xin-tong-tai granule protects atherosclerosis by regulating oxidative stress through NOX/ROS/NF-κB signal pathway

BACKGROUND

Xin-tong-tai Granule (XTTG), a traditional Chinese medicine, has been used to treat atherosclerosis (AS), but its mechanism is poorly understood. Intriguingly, oxidative stress has been recognized as vital factors in the treatment of atherosclerosis.

PURPOSE

This study aims to explore the potential mechanism of XTTG for treating AS.

METHODS

An in-vivo model of AS was established by feeding ApoE-/- mice with a high-fat diet (HFD), and the Human Aortic Vascular Smooth Muscle Cells (HAVSMCs) were induced by oxidized low-density lipoprotein (ox-LDL) in vitro. After treatment, the blood lipid levels and pathological aortic changes of each group were observed, and the cell proliferation and lipid droplet aggregation in each group were evaluated. The oxidative stress indicators such as malondialdehyde (MDA) and superoxide dismutase (SOD) levels and related NOX/ROS/NF-κB signaling pathway indicators were observed.

RESULTS

XTTG improved blood lipid levels and pathological aortic changes of ApoE-/- mice with HFD feeding, inhibited HAVSMCs proliferation and lipid droplet aggregation induced by ox-LDL, reduced MDA content, increased SOD content, inhibited NOX4 and p22phox protein expression, downregulated ROS content, inhibited IKK-α, IKK-β, NF-κB protein and mRNA expression and the phosphorylation of NF-κB.

CONCLUSION

XTTG can inhibit NOX/ROS/NF-κB signaling pathway, reduce damages caused by oxidative stress, and exert anti-AS effects.

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.

The cell origins of foam cell and lipid metabolism regulated by mechanical stress in atherosclerosis

Atherosclerosis is an inflammatory disease initiated by endothelial activation, in which lipoprotein, cholesterol, extracellular matrix, and various types of immune and non-immune cells are accumulated and formed into plaques on the arterial wall suffering from disturbed flow, characterized by low and oscillating shear stress. Foam cells are a major cellular component in atherosclerotic plaques, which play an indispensable role in the occurrence, development and rupture of atherosclerotic plaques. It was previously believed that foam cells were derived from macrophages or smooth muscle cells, but recent studies have suggested that there are other sources of foam cells. Many studies have found that the distribution of atherosclerotic plaques is not random but distributed at the bend and bifurcation of the arterial tree. The development and rupture of atherosclerotic plaque are affected by mechanical stress. In this review, we reviewed the advances in foam cell formation in atherosclerosis and the regulation of atherosclerotic plaque and lipid metabolism by mechanical forces. These findings provide new clues for investigating the mechanisms of atherosclerotic plaque formation and progression.