Elevated Hepcidin Expression in Human Carotid Atheroma: Sex-Specific Differences and Associations with Plaque Vulnerability

Hepcidin is upregulated by increased body iron stores and inflammatory cytokines. It is associated with cardiovascular events, arterial stiffness, and increased iron accumulation in human atheroma with hemorrhage. However, it is unknown whether the expression of hepcidin in human carotid plaques is related to plaque severity and whether hepcidin expression differs between men and women. Carotid samples from 58 patients (38 males and 20 females) were immunostained with hepcidin, macrophages, ferritin, and transferrin receptor. Immunocytochemistry of hepcidin was performed on THP-1 macrophages exposed to iron or 7betahydroxycholesterol. Hepcidin expression significantly increases with the progression of human atherosclerotic plaques. Plaques of male patients have significantly higher levels of hepcidin. Expressions of hepcidin are significantly correlated with the accumulation of CD68-positive macrophages and transferrin receptor 1 (TfR1) and apoptosis. In vitro, hepcidin is significantly increased in macrophages exposed to iron and moderately increased following 7-oxysterol treatment. In the cultured cells, suppression of hepcidin protected against macrophage cell death, lysosomal membrane permeabilization, and oxidative stress. Hepcidin may play a crucial role in the development and progression of atherosclerosis. The differential expression of hepcidin in male and female patients and its significant correlations with plaque severity, highlight the potential of hepcidin as a biomarker for risk stratification and therapeutic targeting in atherosclerosis.

Preparation of a Single-Cell Suspension from Mouse Carotid Arteries for Single-Cell Sequencing

Carotid arteries are major blood vessels in the neck that supply blood and oxygen to the brain, but carotid stenosis occurs when carotid arteries are clogged by plaque. Revealing the cellular composition of the carotid artery at the single-cell level is essential for treating carotid atherosclerosis. However, there is no ready-to-use protocol for the preparation of single-cell suspensions from carotid arteries. To obtain a suitable protocol for the dissociation of normal carotid arteries at the single-cell level with less damage to cells, we designed a two-step digestion method by integrating the digestion process of collagenase/DNase and trypsin. Acridine orange/propidium iodide (AO/PI) dual-fluorescence counting was used to detect cell viability and concentration, and it was found that the single-cell suspension satisfied the requirements for single-cell sequencing, with the viability of cells over 85% and a high cell concentration. After single-cell data processing, a median of ~2500 transcripts per cell were detected in each carotid artery cell. Notably, a variety of cell types of the normal carotid artery, including vascular smooth muscle cells (VSMCs), fibroblasts, endothelial cells (ECs), and macrophages and dendritic cells (Mφ/DCs), were concurrently detectable. This protocol may be applied to prepare a single-cell suspension of blood vessels from other tissues with appropriate modifications.

Cigarette tar accelerates atherosclerosis progression via RIPK3-dependent necroptosis mediated by endoplasmic reticulum stress in vascular smooth muscle cells

BACKGROUND

Tar is the main toxic of cigarettes, and its effect on atherosclerosis progression and the underlying mechanisms remain largely unknown. Vascular smooth muscle cells (VSMCs) play a key role in atherogenesis and plaque vulnerability. The present study sought to investigate the mechanism of atherosclerosis progression through tar-induced VSMC necroptosis, a recently described form of necrosis.

METHODS

The effect of tar on atherosclerosis progression and VSMC necroptosis was examined in ApoE-/- mice and cultured VSMCs. The role of necroptosis in tar-induced plaque development was evaluated in RIPK3-deletion mice (ApoE-/-RIPK3-/-). The key proteins of necroptosis in carotid plaques of smokers and non-smokers were also examined. Quantitative proteomics of mice aortas was conducted to further investigate the underlying mechanism. Pharmacological approaches were then applied to modulate the expression of targets to verify the regulatory process of tar-induced necroptosis.

RESULTS

Tar administration led to increased atherosclerotic plaque area and reduced collagen and VSMCs in ApoE-/- mice. The expression of RIPK1、RIPK3、and MLKL in VSMCs of plaques were all increased in tar-exposed mice and smokers. RIPK3 deletion protected against VSMC loss and plaque progression stimulated by tar. In mechanistic studies, quantitative proteomics analysis of ApoE-/- mice aortas suggested that tar triggered endoplasmic reticulum (ER) stress. PERK-eIF2α-CHOP axis was activated in tar-treated VSMCs and atherosclerotic plaque. Inhibition of ER stress using 4PBA significantly reduced plaque progression and VSMC necroptosis. Further study revealed that ER stress resulted in calcium (Ca2+) release into mitochondria and cytoplasm. Elevated Ca2+ levels lead to mitochondrial dysfunction and excessive reactive oxygen species (ROS) production, which consequently promote RIPK3-dependent necroptosis. In addition, Ca2+/calmodulin-dependent protein kinase II (CaMKII) activated by cytosolic Ca2+ overload binds to RIPK3, accounting for necroptosis.

CONCLUSION

The findings revealed that cigarette tar promoted atherosclerosis progression by inducing RIPK3-dependent VSMC necroptosis and identified novel avenues of ER stress and Ca2+ overload.

Dengyinnaotong attenuates atherosclerotic lesions, gut dysbiosis and intestinal epithelial barrier impairment in the high fat diet-fed ApoE-/- mice

ETHNOPHARMACOLOGICAL RELEVANCE

Dengyinnaotong (DYNT) is a traditional Chinese medicine-based patent drug officially approved for the treatment of ischemic stroke primarily based on its indigenous application for the treatment of cardiovascular and cerebrovascular diseases in Southwest China. Atherosclerosis is the principal pathology underlying the pathogenesis of ischemic stroke and coronary artery disease. However, whether DYNT is effective at mitigating atherosclerosis remains unknown.

AIMS OF THE STUDY

The purpose of the current study is to evaluate the potential impact of DYNT treatment on the atherosclerotic lesions and associated pathological mechanisms.

MATERIALS AND METHODS

Histological, immunohistochemical, molecular biological approaches were adopted to investigate the pharmacological impact of DYNT treatment on atherosclerosis and associated pathophysiological alterations in the high fat diet (HFD)-fed ApoE gene deficient (ApoE-/-) mice.

RESULTS

DYNT treatment reduced the size of the atherosclerotic plaques, alleviated the necrotic core, lowered the lipid retention, mitigated the macrophagic burden and decreased the expression of proatherogenic chemokine Ccl2 in the atherosclerotic lesions. DYNT treatment also offered partial protection against atherogenic dyslipidemia and mitigated hepatic lipid content as well as fatty liver pathologies in the HFD-fed ApoE-/- mice. Furthermore, DYNT treatment protected against atherosclerosis-associated gut dysbiosis and impairment in the intestinal epithelial barrier.

CONCLUSIONS

Our work provides novel preclinical evidence that underpins the multifaceted effects of DYNT in the control of atherosclerosis.

Identification of key pyroptosis-related genes and microimmune environment among peripheral arterial beds in atherosclerotic arteries

Atherosclerosis is a chronic inflammatory disease characterized with innate and adaptive immunity but also involves pyroptosis. Few studies have explored the role of pyroptosis in advanced atherosclerotic plaques from different vascular beds. Here we try to identify the different underlying function of pyroptosis in the progression of atherosclerosis between carotid arteries and femoral. arteries. We extracted gene expression levels from 55 advanced carotid or femoral atherosclerotic plaques. The pyroptosis score of each sample was calculated by single-sample-gene-set enrichment analysis (ssGSEA). We then divided the samples into two clusters: high pyroptosis scores cluster (PyroptosisScoreH cluster) and low pyroptosis scores cluster (PyroptosisScoreL cluster), and assessed functional enrichment and immune cell infiltration in the two clusters. Key pyroptosis related genes were identified by the intersection between results of Cytoscape and LASSO (Least Absolute Shrinkage and Selection Operator) regression analysis. Finally, all key pyroptosis related genes were validated in vitro. We found all but one of the 29 carotid plaque samples belonged to the PyroptosisScoreH cluster and the majority (19 out of 26) of femoral plaques were part of the PyroptosisScoreL cluster. Atheromatous plaque samples in the PyroptosisScoreL cluster had higher proportions of gamma delta T cells, M2 macrophages, myeloid dendritic cells (DCs), and cytotoxic lymphocytes (CTLs), but lower proportions of endothelial cells (ECs). Immune full-activation pathways (e.g., NOD-like receptor signaling pathway and NF-kappa B signaling pathway) were highly enriched in the PyroptosisScoreH cluster. The key pyroptosis related genes GSDMD, CASP1, NLRC4, AIM2, and IL18 were upregulated in advanced carotid atherosclerotic plaques. We concluded that compared to advanced femoral atheromatous plaques, advanced carotid atheromatous plaques were of higher grade of pyroptosis. GSDMD, CASP1, NLRC4, AIM2, and IL18 were the key pyroptosis related genes, which might provide a new sight in the prevention of fatal strokes in advanced carotid atherosclerosis.

Chronic Administration of Methamphetamine Aggravates Atherosclerotic Vulnerable Plaques in Apolipoprotein E Knockout Mice Fed with a High-cholesterol Diet

BACKGROUND

It has been observed previously that chronic methamphetamine (METH) administration could upregulate neuropeptide Y (NPY) expression and promote atherosclerotic formation in apolipoprotein E knockout (ApoE-/-) mice fed with a normal cholesterol or high diet and NPY might be involved in the pathogenesis of METHinduced atherogenic effects through NPY Y1 receptor pathway. Vulnerable coronary atherosclerotic plaque (VP) is a critical pathological finding responsible for the acute coronary syndrome (ACS). In this study, we explored whether METH abuse could aggravate the formation of VP in ApoE-/- mice fed with high cholesterol diet.

OBJECTIVE

The purpose of this study was to observe if chronic METH administration could aggravate vulnerable plaque (VP) formation in ApoE-/- mice fed with a highcholesterol diet.

METHODS

Male ApoE-/- mice fed with a high-cholesterol diet were intraperitoneally injected with normal saline (NS) or 8 mg/kg/day METH (M8) for 24 weeks. Body weight was monitored from baseline to 24 weeks at 2 weeks intervals. After 24 weeks of treatment, plasma lipid variables were measured. Movat's staining and immunohistochemical staining were performed on frozen sections of the aortic roots to calculate VP percentage and intraplaque hemorrhage (IPH) percentage and detect expression of NPY, vascular endothelial growth factor (VEGF), and CD31. In vitro, the expressions of Y2R, VEGF, and CD31 were detected by immunofluorescence staining in aortic endothelial cells incubated with PBS, 100μM METH, 10nmol NPY, or 100μM METH plus 10nmol NPY for 12 hours.

RESULTS

The CD31 positive area, percentage of IPH, VP, and the expressions of NPY and VEGF were significantly increased in the M8 group than in the NS group. In vitro, the expressions of Y2R, VEGF, and CD31 were significantly increased in the METH+NPY group than in the PBS, METH, and NPY groups and these effects could be blunted by treatment with a Y2R antagonist or DPPIV inhibitor.

CONCLUSION

Chronic METH administration could aggravate VP in ApoE-/- mice fed with a high-cholesterol diet, possibly through upregulating vascular NPY and VEGF expression and promoting angiogenesis and vessel rupture in atherosclerotic plaques. Our findings indicated that increased VP formation might contribute to the development of acute coronary syndrome post-chronic METH abuse by activating DPPIV/NPY/Y2R pathway.

miR-223-3p Prevents Necroptotic Macrophage Death by Targeting Ripk3 in a Negative Feedback Loop and Consequently Ameliorates Advanced Atherosclerosis

BACKGROUND

The formation of large necrotic cores results in vulnerable atherosclerotic plaques, which can lead to severe cardiovascular diseases. However, the specific regulatory mechanisms underlying the development of necrotic cores remain unclear.

METHODS

To evaluate how the modes of lesional cell death are reprogrammed during the development of atherosclerosis, the expression levels of key proteins that are involved in the necroptotic, apoptotic, and pyroptotic pathways were compared between different stages of plaques in humans and mice. Luciferase assays and loss-of-function studies were performed to identify the microRNA-mediated regulatory mechanism that protects foamy macrophages from necroptotic cell death. The role of this mechanism in atherosclerosis was determined by using a knockout mouse model with perivascular drug administration and tail vein injection of microRNA inhibitors in Apoe-/- mice.

RESULTS

Here, we demonstrate that the necroptotic, rather than the apoptotic or pyroptotic, pathway is more activated in advanced unstable plaques compared with stable plaques in both humans and mice, which closely correlates with necrotic core formation. The upregulated expression of Ripk3 (receptor-interacting protein kinase 3) promotes the C/EBPβ (CCAAT/enhancer binding protein beta)-dependent transcription of the microRNA miR-223-3p, which conversely inhibits Ripk3 expression and forms a negative feedback loop to regulate the necroptosis of foamy macrophages. The knockout of the Mir223 gene in bone marrow cells accelerates atherosclerosis in Apoe-/- mice, but this effect can be rescued by Ripk3 deficiency or treatment with the necroptosis inhibitors necrostatin-1 and GSK-872. Like the Mir223 knockout, treating Apoe-/- mice with miR-223-3p inhibitors increases atherosclerosis.

CONCLUSIONS

Our study suggests that miR-223-3p expression in macrophages protects against atherosclerotic plaque rupture by limiting the formation of necrotic cores, thus providing a potential microRNA therapeutic candidate for atherosclerosis.

Mechanism of Curcumin Inhibiting NLRP3 Inflammatory Body and Improving Atherosclerotic Endothelial Cell Injury

BACKGROUND

Curcumin is a kind of natural hydrophobic polyphenol isolated from the stem of the Curcuma plant. To investigate regulatory curcumin effect on atherosclerotic endothelial cell injury.

METHODS

30 male ApoE-/- mice were selected and divided into the control group, model group, and curcumin group (n = 10). The curcumin group was treated with curcumin by gavage. Body weight, atherosclerotic plaque area, plaque cap thickness, blood lipid levels, total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C) content, nitric oxide (NO) content, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) content and circulating endothelial cell number of mice in each group were detected. Western blot detected NACHT, LRR, and receptor family pyrin domain-containing 3 (NLRP3) and Asc-type amino acid transporter protein 1 (ASC) protein level in mice. Human aortic endothelial cells (HAEC) were cultured to establish an atherosclerotic endothelial cell injury model in vivo. Cell counting kit-8 (CCK-8) detected the cell viability of each group.

RESULTS

Body weight, atherosclerotic plaque area, plaque cap thickness, TC, TG, and LDL-C content of blood lipid levels of the curcumin group were obviously reduced as compared with the model group (p < 0.05), the content of NO and the number of circulating endothelial cells in curcumin group were obviously decreased (p < 0.05). The cell viability of the curcumin group was obviously higher than that of the model group (p < 0.05). The NO content of the curcumin group was lower than the model group (p < 0.05). The content of IL-1β and TNF-α in the curcumin group was obviously lower than in the model group (p < 0.05). Compared with the model group, the expression of receptor family pyrin domain-containing 3 (NLRP3) and ASC protein in the curcumin group was decreased obviously (p < 0.05).

CONCLUSION

Curcumin improves endothelial cell injury in atherosclerosis by inhibiting the expression of NLRP3 inflammatory bodies.

Unveiling the role of ABI3 and hub senescence-related genes in macrophage senescence for atherosclerotic plaque progression

BACKGROUND

Atherosclerosis, characterized by abnormal arterial lipid deposition, is an age-dependent inflammatory disease and contributes to elevated morbidity and mortality. Senescent foamy macrophages are considered to be deleterious at all stages of atherosclerosis, while the underlying mechanisms remain largely unknown. In this study, we aimed to explore the senescence-related genes in macrophages diagnosis for atherosclerotic plaque progression.

METHODS

The atherosclerosis-related datasets were retrieved from the Gene Expression Omnibus (GEO) database, and cellular senescence-associated genes were acquired from the CellAge database. R package Limma was used to screen out the differentially expressed senescence-related genes (DE-SRGs), and then three machine learning algorithms were applied to determine the hub DE-SRGs. Next, we established a nomogram model to further confirm the clinical significance of hub DE-SRGs. Finally, we validated the expression of hub SRG ABI3 by Sc-RNA seq analysis and explored the underlying mechanism of ABI3 in THP-1-derived macrophages and mouse atherosclerotic lesions.

RESULTS

A total of 15 DE-SRGs were identified in macrophage-rich plaques, with five hub DE-SRGs (ABI3, CAV1, NINJ1, Nox4 and YAP1) were further screened using three machine learning algorithms. Subsequently, a nomogram predictive model confirmed the high validity of the five hub DE-SRGs for evaluating atherosclerotic plaque progression. Further, the ABI3 expression was upregulated in macrophages of advanced plaques and senescent THP-1-derived macrophages, which was consistent with the bioinformatics analysis. ABI3 knockdown abolished macrophage senescence, and the NF-κB signaling pathway contributed to ABI3-mediated macrophage senescence.

CONCLUSION

We identified five cellular senescence-associated genes for atherogenesis progression and unveiled that ABI3 might promote macrophage senescence via activation of the NF-κB pathway in atherogenesis progression, which proposes new preventive and therapeutic strategies of senolytic agents for atherosclerosis.

Par3L, a polarity protein, promotes M1 macrophage polarization and aggravates atherosclerosis in mice via p65 and ERK activation

Proinflammatory M1 macrophages are critical for the progression of atherosclerosis. The Par3-like protein (Par3L) is a homolog of the Par3 family involved in cell polarity establishment. Par3L has been shown to maintain the stemness of mammary stem cells and promote the survival of colorectal cancer cells. In this study, we investigated the roles of the polar protein Par3L in M1 macrophage polarization and atherosclerosis. To induce atherosclerosis, Apoe-/- mice were fed with an atherosclerotic Western diet for 8 or 16 weeks. We showed that Par3L expression was significantly increased in human and mouse atherosclerotic plaques. In primary mouse macrophages, oxidized low-density lipoprotein (oxLDL, 50 μg/mL) time-dependently increased Par3L expression. In Apoe-/- mice, adenovirus-mediated Par3L overexpression aggravated atherosclerotic plaque formation accompanied by increased M1 macrophages in atherosclerotic plaques and bone marrow. In mouse bone marrow-derived macrophages (BMDMs) or peritoneal macrophages (PMs), we revealed that Par3L overexpression promoted LPS and IFNγ-induced M1 macrophage polarization by activating p65 and extracellular signal-regulated kinase (ERK) rather than p38 and JNK signaling. Our results uncover a previously unidentified role for the polarity protein Par3L in aggravating atherosclerosis and favoring M1 macrophage polarization, suggesting that Par3L may serve as a potential therapeutic target for atherosclerosis.

Moxibustion's protective role against atherosclerosis: Inhibition of Ca2+ overload-triggered oxidative stress and inflammatory response via P2Y12/PI3K/AKT pathway

OBJECTIVE

This study aims to investigate the protective mechanism of moxibustion in combating atherosclerosis (AS).

METHODS

Apolipoprotein E (ApoE)-deficient mice, aged 8 weeks, were randomly assigned into four groups: the model group (n = 6), SC79 group (n = 6), moxibustion group (n = 6), and moxibustion+SC79 group (n = 6). All mice were fed with a high-fat diet (HFD). Concurrently, 8-week-old C57BL/6 mice of the same genetic background were utilized as the control group (n = 6) and were given a regular diet. Macrophages were isolated via flow cytometry. The intracellular Ca2+ expression in macrophages was evaluated, and aortic plaques were quantitatively assessed through en face oil red O and Masson staining. The presence of macrophages and smooth muscle cells in AS plaques was determined by MAC-3 and α-smooth muscle actin (α-SMA) immunohistochemistry. The relative fluorescence intensity of nuclear factor-κB (NF-κB) in macrophages was identified by immunofluorescence staining. The expressions of proteins related to the P2Y12/phosphatidylinositol 3-hydroxy kinase (PI3K)/protein kinase B (AKT) signaling pathway were examined by Western blotting.

RESULTS

Moxibustion reduced free Ca2+ expression in macrophage cytoplasm, inhibiting Ca2+ influx and oxidative stress. Significant reductions in atherosclerotic plaque formation and inflammation markers, including TNF-α and IL-1β, were noted in the moxibustion group. Moxibustion modulated the P2Y12/PI3K/AKT pathway, impacting various inflammatory and oxidative stress-related proteins. Introduction of the AKT activator SC79 counteracted moxibustion's benefits, highlighting the P2Y12/PI3K/AKT pathway's central role.

CONCLUSION

Moxibustion, through the P2Y12/PI3K/AKT signaling pathway, can inhibit Ca2+ overload-induced oxidative stress and inflammatory response, decrease macrophage infiltration, and increase the content of smooth muscle cells and collagen, thereby exerting a protective effect against AS.

Inhibition of EphA2 protects against atherosclerosis by synergizing with statins to mitigate macrophage inflammation

Statins are highly prevalent in patients with coronary artery disease. Statins exert their anti-inflammatory effects on the vascular wall and circulating levels of pro-inflammatory cytokines. However, increasing attention revealed the exacerbation of macrophage inflammation induced by statins, and a clear mechanistic explanation of whether the detrimental effects of statins on macrophage inflammatory phenotypes outweigh the beneficial effects is has not yet been established. Here, RNA-sequencing and RT-qPCR analyses demonstrated that statins significantly upregulated EphA2, Nlrp3, IL-1β and TNF-α expression in macrophages. Mechanistically, we found that atorvastatin reduced KLF4 binding to the EphA2 promoter using KLF4-chromatin immunoprecipitation, suppressed HDAC11-mediated deacetylation and subsequently led to enhanced EphA2 transcription. The 4D-label-free proteomics analysis further confirmed the upregulated EphA2 and inflammatory signals. Furthermore, the proinflammatory effect of atorvastatin was neutralized by an addition of recombinant Fc-ephrinA1, a selective Eph receptor tyrosine kinase inhibitor (ALW-II-41-27) or EphA2-silencing adenovirus (siEphA2). In vivo, EphA2 was identified a proatherogenic factor and apoE-/- mice placed on a high-fat diet following gastric gavage with atorvastatin exhibited a consistent elevation in EphA2 expression. We further observed that the transfection with siEphA2 in atorvastatin-treated mice significantly attenuated atherosclerotic plaque formation and abrogated statin-orchestrated macrophages proinflammatory genes expression as compared to that in atorvastatin alone. Increased plaque stability index was also observed following the addition of siEphA2, as evidenced by increased collagen and smooth muscle content and diminished lipid accumulation and macrophage infiltration. The data suggest that blockage of EphA2 provides an additional therapeutic benefit for further improving the anti-atherogenic effects of statins.

Oxidized low-density lipoprotein induces M2-type differentiation of macrophages to promote the protracted progression of atherosclerotic inflammation in high-fat diet-fed ApoE -/- mice

In this study, the significance of oxidized low-density lipoprotein (ox-LDL) in promoting the progression of atherosclerosis was investigated by inducing the differentiation of macrophages into the M2 subtype within a high-fat diet-induced ApoE -/- mouse model. The study also evaluated the effects of β2-AR agonists and blockers on this process. Ox-LDL was found to have significantly promoted the differentiation of macrophages into the M2 type and induced related functional alterations. Furthermore, it activated the pyroptosis pathway and encouraged the release of lactate dehydrogenase. The administration of β2-AR agonists intensified these processes, while β2-AR blockers had the opposite effect. In animal experiments, the model group displayed elevated numbers of M2-type macrophages beneath the aortic root intima, an increased rate of plaque destruction, and the formation of atherosclerotic plaques compared to the control group. The SAL (Salbutamol) group exhibited even more severe plaque development than the model group. Conversely, the ICI (ICI118551) group demonstrated M2-type macrophage levels comparable to the control group, with a higher plaque destruction rate than controls but significantly lower than the model group, and no atherosclerotic plaques. These findings suggest that ox-LDL promoted the differentiation of recruited monocytes into M2-type macrophages, leading to a shift in the inflammatory response from M1 to M2 macrophages. This alteration resulted in the persistence of atherosclerotic inflammation, as M2-type macrophages were prone to cell membrane rupture (such as pyroptosis), contributing to the continuous recruitment of circulating monocytes and heightened inflammatory reactions within atherosclerotic plaques. Consequently, this process fueled the progression of atherosclerosis.

IGFBPL1 inhibits macrophage lipid accumulation by enhancing the activation of IGR1R/LXRα/ABCG1 pathway

Lipid accumulation in macrophages plays an important role in atherosclerosis and is the major cause of atherosclerotic cardiovascular disease. Reducing lipid accumulation in macrophages is an effective therapeutic target for atherosclerosis. Insulin-like growth factor 1 (IGF-1) exerts the anti-atherosclerotic effects by inhibiting lipid accumulation in macrophages. Furthermore, almost all circulating IGF-1 combines with IGF binding proteins (IGFBPs) to activate or inhibit the IGF signaling. However, the mechanism of IGFBPs in macrophage lipid accumulation is still unknown. GEO database analysis showed that among IGFBPS family members, IGFBPL1 has the largest expression change in unstable plaque. We found that IGFBPL1 was decreased in lipid-laden THP-1 macrophages. Through oil red O staining, NBD-cholesterol efflux, liver X receptor α (LXRα) transcription factor and IGR-1 receptor blocking experiments, our results showed that IGFBPL1 inhibits lipid accumulation in THP-1 macrophages through promoting ABCG1-meditated cholesterol efflux, and IGFBPL1 regulates ABCG1 expression and macrophage lipid metabolism through IGF-1R/LXRα pathway. Our results provide a theoretical basis of IGFBPL1 in the alternative or adjunct treatment options for atherosclerosis by reducing lipid accumulation in macrophages.

Tetrazine-Based Ratiometric Nitric Oxide Sensor Identifies Endogenous Nitric Oxide in Atherosclerosis Plaques by Riding Macrophages as a Smart Vehicle

Atherosclerosis (AS) is the formation of plaques in blood vessels, which leads to serious cardiovascular diseases. Current research has disclosed that the formation of AS plaques is highly related to the foaming of macrophages. However, there is a lack of detailed molecular biological mechanisms. We proposed a "live sensor" by grafting a tetrazine-based ratiometric NO probe within macrophages through metabolic and bio-orthogonal labeling. This "live sensor" was proved to target the AS plaques with a diameter of only tens of micrometers specifically and visualized endogenous NO at two lesion stages in the AS mouse model. The ratiometric signals from the probe confirmed the participation of NO during AS and indicated that the generation of endogenous NO increased significantly as the lesion progressed. Our proposal of this "live sensor" provided a native and smart strategy to target and deliver small molecular probes to the AS plaques at the in vivo level, which can be used as universal platforms for the detection of reactive molecules or microenvironmental factors in AS.

Bioinformatics analysis of carotid vulnerable plaques associated with the SARS-CoV-2 pattern

The rupture of carotid artery vulnerable plaque plays a critical role in ischemic stroke, and the widely spread new coronavirus in recent years plays a certain role in the development of human carotid artery vulnerable plaque, we screened out 27 differential expression genes (DEGs) of stable plaque and vulnerable plaque associated with the new coronavirus. Through the construction of the protein-protein interaction (PPI) network, the Cathepsin B (CTSB) and Niemann-Pick Disease Type 2 (NPC2) were identified as crucial expression genes, and further, we confirmed the validity of core gene expression in two validation sets. Additionally, we discovered a significant connection between CTSB, NPC2 and 28 different kinds of immune cells in carotid plaque tissue. We screened out 65 target interacting drugs based on 10 differentially expressed genes through online tools and finally verified the high expression of 2 core genes in fragile plaques through clinical sample experiments. These findings imply that two core genes may be novel targets for molecular diagnostics and immunotherapy of vulnerable plaques.

Atherosclerotic plaque development in mice is enhanced by myeloid ZEB1 downregulation

Accumulation of lipid-laden macrophages within the arterial neointima is a critical step in atherosclerotic plaque formation. Here, we show that reduced levels of the cellular plasticity factor ZEB1 in macrophages increase atherosclerotic plaque formation and the chance of cardiovascular events. Compared to control counterparts (Zeb1WT/ApoeKO), male mice with Zeb1 ablation in their myeloid cells (Zeb1∆M/ApoeKO) have larger atherosclerotic plaques and higher lipid accumulation in their macrophages due to delayed lipid traffic and deficient cholesterol efflux. Zeb1∆M/ApoeKO mice display more pronounced systemic metabolic alterations than Zeb1WT/ApoeKO mice, with higher serum levels of low-density lipoproteins and inflammatory cytokines and larger ectopic fat deposits. Higher lipid accumulation in Zeb1∆M macrophages is reverted by the exogenous expression of Zeb1 through macrophage-targeted nanoparticles. In vivo administration of these nanoparticles reduces atherosclerotic plaque formation in Zeb1∆M/ApoeKO mice. Finally, low ZEB1 expression in human endarterectomies is associated with plaque rupture and cardiovascular events. These results set ZEB1 in macrophages as a potential target in the treatment of atherosclerosis.

Knockdown of ADAMDEC1 ameliorates ox-LDL-induced endothelial cell injury and atherosclerosis progression

This study was designed to investigate the role of a disintegrin and metalloproteinase domain-like protein decysin 1 (ADAMDEC-1) in atherosclerosis (AS). The Gene Expression Omnibus (GEO) database was utilized to identify differentially expressed genes (DEGs) between carotid atheroma plaque and carotid tissue adjacent atheroma plaque obtained from AS patients. Gene functional enrichment analysis was conducted on DEGs using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). QRT-PCR was employed to quantify mRNAs expression. AS animal model was established using ApoE-/- mice; serum triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were detected. Aortic sinus atherosclerotic lesions were observed using H&E staining and Oil Red O staining. ADAMDEC-1 was silenced using small interfering RNAs (siRNAs) in human vascular smooth muscle cells (HVSMCs). Cell proliferation, migration, and cell cycle progression were detected by cell count kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EDU), wound scratch healing assay, transwell assay, and flow cytometry, respectively. Western blot was used to evaluate various protein expression levels. Our results showed that ADAMDEC-1 was highly expressed in the serum of AS patients, consistent with the in silico results. The elevated TG, LDL-C, and HDL-C levels along with H&E and Oil Red O staining confirmed the successful establishment of the AS mouse model. ADAMDEC-1 expression was also elevated in AS mice. ADAMDEC-1 knockdown in HVSMCs suppressed cell proliferation, inhibited the expression of proliferating cell nuclear antigen (PCNA), and reduced the levels of matrix metalloproteinases (MMP2 and MMP9) proteins. Protein-protein interaction (PPI) analysis indicated that ADAMDEC-1 was associated with CXCL9, CCR5, TNF-α, TNFR1, and NF-κB-p50. The expression levels of CXCL9, CCR5, TNF-α, TNFR1, and NF-κB-p50 increased, while ADAMDEC-1 knockdown attenuated the expression of these proteins. Our study findings substantiate that ADAMDEC-1 may represent a novel target for AS.

LncRNA NIPA1-SO confers atherosclerotic protection by suppressing the transmembrane protein NIPA1

Long non-coding RNAs (lncRNAs) are emerging as important players in gene regulation and cardiovascular diseases. However, the roles of lncRNAs in atherosclerosis are poorly understood. In the present study, we found that the levels of NIPA1-SO were decreased while those of NIPA1 were increased in human atherosclerotic plaques. Furthermore, NIPA1-SO negatively regulated NIPA1 expression in human umbilical vein endothelial cells (HUVECs). Mechanistically, NIPA1-SO interacted with the transcription factor FUBP1 and the NIPA1 gene. The effect of NIPA1-SO on NIPA1 protein levels was reversed by the knockdown of FUBP1. NIPA1-SO overexpression increased, whilst NIPA1-SO knockdown decreased BMPR2 levels; these effects were enhanced by the knockdown of NIPA1. The overexpression of NIPA1-SO reduced while NIPA1-SO knockdown increased monocyte adhesion to HUVECs; these effects were diminished by the knockdown of BMPR2. The lentivirus-mediated-overexpression of NIPA1-SO or gene-targeted knockout of NIPA1 in low-density lipoprotein receptor-deficient mice reduced monocyte-endothelium adhesion and atherosclerotic lesion formation. Collectively, these findings revealed a novel anti-atherosclerotic role for the lncRNA NIPA1-SO and highlighted its inhibitory effects on vascular inflammation and intracellular cholesterol accumulation by binding to FUBP1 and consequently repressing NIPA1 expression.

Effect of miR-663 on atherosclerosis by regulating the proliferation of vascular smooth muscle cells in lipid plaques

OBJECTIVES

Atherosclerosis (AS) is the main cause of coronary heart disease, cerebral infarction, and peripheral vascular disease. microRNAs (miRNAs) are widely distributed in the human body and closely related to the pathological progress of AS. This study probed into the function of miR-663 in AS.

METHODS

The atherosclerotic plaques, cholesterol (CHOL), low-density lipoprotein (LDL), inflammatory factors, and miR-663 expression in ApoE-/- mice on high-fat diet were evaluated. The overexpressing miR-663 adenovirus was injected into ApoE-/- mice, followed by measurement of type III collagen (Col III), matrix metalloproteinase (MMP)-2, α-SMA, osteopontin, and CD31. miR-663 mimic or inhibitor was introduced into vascular smooth muscle cells (VSMCs) stimulated by oxidized LDL (Ox-LDL), and cell proliferation and IL-6 and IL-18 secretion were evaluated. The binding relationship between miR-663 and HMGA2 was verified, followed by the determination of HMGA2 role in VSMC proliferation.

RESULTS

Atherosclerotic plaques appeared in ApoE-/- mice on high-fat diet, with increased CHOL, LDL, osteopontin, MMP-2 and Col III and decreased miR-663, α-SMA and CD31. miR-663 overexpression downregulated osteopontin, MMP-2 and Col III and upregulated α-SMA and CD31 in ApoE-/- mice on high-fat diet. With Ox-LDL concentration increase, VSMC proliferation was promoted and miR-663 was downregulated. miR-663 overexpression inhibited proliferation of Ox-LDL-stimulated VSMCs and reduced levels of inflammatory factor levels, whereas silencing miR-663 did the opposite. miR-663 targeted HMGA2. HMGA2 overexpression partially reversed the inhibitory effect of miR-663 overexpression on VSMC proliferation.

CONCLUSION

miR-663 targeted HMGA2 to inhibit VSMC proliferation and AS development, which may offer insights into AS treatment.

Nogo-B mediates endothelial oxidative stress and inflammation to promote coronary atherosclerosis in pressure-overloaded mouse hearts

AIMS

Endothelial dysfunction plays a pivotal role in atherosclerosis, but the detailed mechanism remains incomplete understood. Nogo-B is an endoplasmic reticulum (ER)-localized protein mediating ER-mitochondrial morphology. We previously showed endothelial Nogo-B as a key regulator of endothelial function in the setting of hypertension. Here, we aim to further assess the role of Nogo-B in coronary atherosclerosis in ApoE-/- mice with pressure overload.

METHODS AND RESULTS

We generated double knockout (DKO) mouse models of systemically or endothelium-specifically excising Nogo-A/B gene on an ApoE-/- background. After 7 weeks of transverse aortic constriction (TAC) surgery, compared to ApoE-/- mice DKO mice were resistant to the development of coronary atherosclerotic lesions and plaque rapture. Sustained elevation of Nogo-B and adhesion molecules (VCAM-1/ICAM-1), early markers of atherosclerosis, was identified in heart tissues and endothelial cells (ECs) isolated from TAC ApoE-/- mice, changes that were significantly repressed by Nogo-B deficiency. In cultured human umbilical vein endothelial cells (HUVECs) exposure to inflammatory cytokines (TNF-α, IL-1β), Nogo-B was upregulated and activated reactive oxide species (ROS)-p38-p65 signaling axis. Mitofusin 2 (Mfn2) is a key protein tethering ER to mitochondria in ECs, and we showed that Nogo-B expression positively correlated with Mfn2 protein level. And Nogo-B deletion in ECs or in ApoE-/- mice reduced Mfn2 protein content and increased ER-mitochondria distance, reduced ER-mitochondrial Ca2+ transport and mitochondrial ROS generation, and prevented VCAM-1/ICAM-1 upregulation and EC dysfunction, eventually restrained atherosclerotic lesions development.

CONCLUSION

Our study revealed that Nogo-B is a critical modulator in promoting endothelial dysfunction and consequent pathogenesis of coronary atherosclerosis in pressure overloaded hearts of ApoE-/- mice. Nogo-B may hold the promise to be a common therapeutic target in the setting of hypertension.

Leucine-Rich Alpha-2 Glycoprotein 1 Accumulates in Complicated Atherosclerosis and Promotes Calcification

Atherosclerosis is the primary cause of cardiovascular disease. The development of plaque complications, such as calcification and neo-angiogenesis, strongly impacts plaque stability and is a good predictor of mortality in patients with atherosclerosis. Despite well-known risk factors of plaque complications, such as diabetes mellitus and chronic kidney disease, the mechanisms involved are not fully understood. We and others have identified that the concentration of circulating leucine-rich α-2 glycoprotein 1 (LRG1) was increased in diabetic and chronic kidney disease patients. Using apolipoprotein E knockout mice (ApoE-/-) (fed with Western diet) that developed advanced atherosclerosis and using human carotid endarterectomy, we showed that LRG1 accumulated into an atherosclerotic plaque, preferentially in calcified areas. We then investigated the possible origin of LRG1 and its functions on vascular cells and found that LRG1 expression was specifically enhanced in endothelial cells via inflammatory mediators and not in vascular smooth muscle cells (VSMC). Moreover, we identified that LRG1 was able to induce calcification and SMAD1/5-signaling pathways in VSMC. In conclusion, our results identified for the first time that LRG1 is a direct contributor to vascular calcification and suggest a role of this molecule in the development of plaque complications in patients with atherosclerosis.

Detection of cell-type-enriched long noncoding RNAs in atherosclerosis using single-cell techniques: A brief review

Cardiovascular diseases are the leading causes of mortality and morbidity worldwide. Atherosclerotic plaque underlies the predominant factors and is composed of various cell types, including structure cells, such as endothelial and smooth muscle cells, and immune cells, such as macrophages and T cells. Single-cell RNA sequencing (scRNA-seq) has been extensively applied to decipher these cellular heterogeneities to expand our understanding on the mechanisms of atherosclerosis (AS) and to facilitate identifying cell-type-specific long noncoding RNAs (LncRNAs). LncRNAs have been demonstrated to deeply regulate biological activities at the transcriptional and post-transcriptional levels. A group of well-documented functional lncRNAs in AS have been studied. In our review, we selectively described several lncRNAs involved in the critical process of AS. We highlighted four novel lncRNAs (lncRNA CARMN, LINC00607, PCAT19, LINC01235) detected in scRNA-seq datasets and their functions in AS. We also reviewed open web source and bioinformatic tools, as well as the latest methods to perform an in-depth study of lncRNAs. It is fundamental to annotate functional lncRNAs in the various biological activities of AS, as lncRNAs may represent promising targets in the future for treatment and diagnosis in clinical practice.

Inhibition of Hedgehog signaling ameliorates foam cell formation by promoting autophagy in early atherosclerosis

Macrophages are the origin of most foam cells in the early stage of atherosclerotic plaques. However, the mechanism involved in the formation of macrophage-derived foam cell formation remains unclear. Here, we revealed that the hedgehog (Hh) signaling is critical in autophagy-lysosome pathway regulation and macrophage-derived foam cell formation. Inhibition of Hh signaling by vismodegib ameliorated lipid deposition and oxidative stress level in atherosclerotic plaques in high-fat diet-fed apoE-/- mice. For mechanistic study, how the Hh signaling modulate the process of foam cell formation were accessed afterward. Unexpectedly, we found that suppression of Hh signaling in apoE-/- mice had no significant impact on circulating cholesterol levels, indicating that Hh pathway modulate the procession of atherosclerotic plaque not through a traditional lipid-lowing mechanism. Instead, vismodegib was found to accelerate autophagosomes maturation as well as cholesterol efflux in macrophage-derived foam cell and in turn improve foam cell formation, while autophagy inhibitors (LY294002 or CQ) administration significantly attenuated vismodegib-induced cholesterol efflux and reversed the effect on foam cell formation. Therefore, our result demonstrated that inhibition of the Hh signaling pathway increases cholesterol efflux and ameliorates macrophage-derived foam cell formation by promoting autophagy in vitro. Our data thus suggested a novel therapeutic target of atherosclerosis and indicated the potential of vismodegib to treat atherosclerosis.

Cellular Heterogeneity of Activated Primary Human Macrophages and Associated Drug-Gene Networks: From Biology to Precision Therapeutics

BACKGROUND

Interferon-γ (IFNγ) signaling plays a complex role in atherogenesis. IFNγ stimulation of macrophages permits in vitro exploration of proinflammatory mechanisms and the development of novel immune therapies. We hypothesized that the study of macrophage subpopulations could lead to anti-inflammatory interventions.

METHODS

Primary human macrophages activated by IFNγ (M(IFNγ)) underwent analyses by single-cell RNA sequencing, time-course cell-cluster proteomics, metabolite consumption, immunoassays, and functional tests (phagocytic, efferocytotic, and chemotactic). RNA-sequencing data were analyzed in LINCS (Library of Integrated Network-Based Cellular Signatures) to identify compounds targeting M(IFNγ) subpopulations. The effect of compound BI-2536 was tested in human macrophages in vitro and in a murine model of atherosclerosis.

RESULTS

Single-cell RNA sequencing identified 2 major clusters in M(IFNγ): inflammatory (M(IFNγ)i) and phagocytic (M(IFNγ)p). M(IFNγ)i had elevated expression of inflammatory chemokines and higher amino acid consumption compared with M(IFNγ)p. M(IFNγ)p were more phagocytotic and chemotactic with higher Krebs cycle activity and less glycolysis than M(IFNγ)i. Human carotid atherosclerotic plaques contained 2 such macrophage clusters. Bioinformatic LINCS analysis using our RNA-sequencing data identified BI-2536 as a potential compound to decrease the M(IFNγ)i subpopulation. BI-2536 in vitro decreased inflammatory chemokine expression and secretion in M(IFNγ) by shrinking the M(IFNγ)i subpopulation while expanding the M(IFNγ)p subpopulation. BI-2536 in vivo shifted the phenotype of macrophages, modulated inflammation, and decreased atherosclerosis and calcification.

CONCLUSIONS

We characterized 2 clusters of macrophages in atherosclerosis and combined our cellular data with a cell-signature drug library to identify a novel compound that targets a subset of macrophages in atherosclerosis. Our approach is a precision medicine strategy to identify new drugs that target atherosclerosis and other inflammatory diseases.