Mouse Model Of Atherosclerosis Research Articles

Kindlin-2 Phase Separation in Response to Flow Controls Vascular Stability.

Atheroprotective shear stress preserves endothelial barrier function, while atheroprone shear stress enhances endothelial permeability. Yet, the underlying mechanisms through which distinct flow patterns regulate EC integrity remain to be clarified. This study aimed to investigate the involvement of Kindlin-2, a key component of focal adhesion and endothelial adherens junctions crucial for regulating endothelial cell (EC) integrity and vascular stability. Mouse models of atherosclerosis in EC-specific Kindlin-2 knockout mice (Kindlin-2iΔEC) were used to study the role of Kindlin-2 in atherogenesis. Pulsatile shear (2±4 dynes/cm2) or oscillatory shear (0.5±4 dynes/cm2) were applied to culture ECs. Live-cell imaging, fluorescence recovery after photobleaching assay, and optoDroplet assay were used to study the liquid-liquid phase separation (LLPS) of Kindlin-2. Co-immunoprecipitation, mutagenesis, proximity ligation assay, and transendothelial electrical resistance assay were used to explore the underlying mechanism of flow-regulated Kindlin-2 function. We found that Kindlin-2 localization is altered under different flow patterns. Kindlin-2iΔEC mice showed heightened vascular permeability. Kindlin-2iΔEC were bred onto ApoE-/- mice to generate Kindlin-2iΔEC; ApoE-/- mice, which displayed a significant increase in atherosclerosis lesions. In vitro data showed that in ECs, Kindlin-2 underwent LLPS, a critical process for proper focal adhesion assembly, maturation, and junction formation. Mass spectrometry analysis revealed that oscillatory shear increased arginine methylation of Kindlin-2, catalyzed by PRMT5 (protein arginine methyltransferase 5). Functionally, arginine hypermethylation inhibits Kindlin-2 LLPS, impairing focal adhesion assembly and junction maturation. Notably, we identified R290 of Kindlin-2 as a crucial residue for LLPS and a key site for arginine methylation. Finally, pharmacologically inhibiting arginine methylation reduces EC activation and plaque formation. Collectively, our study elucidates that mechanical force induces arginine methylation of Kindlin-2, thereby regulating vascular stability through its impact on Kindlin-2 LLPS. Targeting Kindlin-2 arginine methylation emerges as a promising hemodynamic-based strategy for treating vascular disorders and atherosclerosis. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02783300.

Aspirin inhibits atherosclerosis through macrophage pyroptosis by interacting with Lactobacillus johnsonii and its metabolite butyrate

Abstract Introduction Atherosclerotic cardiovascular disease (ASCVD) is a chronic progressive disease closely related to metabolism and inflammation. Aspirin inhibits cyclooxygenase (COX) and has antiplatelet aggregation effects, considered as the cornerstone of ASCVD treatment. Numerous studies have shown that gut microbiota (GM) and its metabolites affects host metabolism. Studies have also shown that people taking aspirin exhibit specific changes in the microbiota profile. However, whether the interaction of aspirin with GM and its metabolites affects the therapeutic efficacy of aspirin in treating atherosclerosis (AS) have not been reported. Purpose This study aimed to explore the interaction of aspirin with the GM and its metabolites in the treatment of AS, to reveal the specific mechanism of the GM-metabolite axis and provide potential new targets for the combined treatment of AS. Methods To establish the mouse model of atherosclerosis by high-fat diet, and the atherosclerotic plaque burden and composition were analyzed. The role of GM in aspirin anti-atherosclerosis was explored by antibiotics and fecal microbiota transplantation (FMT). The third generation 16S RNA sequencing was used to explore the effects of aspirin on species diversity and abundance of GM, and to screen differential microorganisms for intervention of AS mice. UHPLC-MS and GC-MS were used to explore the changes of intestinal metabolites induced by aspirin. The correlation between gut microbiota and metabolites was also investigated. Finally, in vitro and in vivo experiments were performed to confirm the effects and mechanisms of metabolites on macrophage pyroptosis and atherosclerosis. Results Aspirin has anti-atherosclerosis effect. After removing gut microbiota, the therapeutic effect of aspirin on atherosclerosis was decreased. Three generations of 16S rRNA gene sequencing results showed that aspirin supplementation alters the diversity of gut microbiota, and increased the relative abundance of Lactobacillus johnsonii(L.johnsonii) and Ligilactobacillus murinus(L.murinus). After gavage of L.johnsonii and L.murinus, the plaque burden and macrophage pyroptosis were significantly reduced in AS mice. Colonization with L.johnsonii and L.murinus significantly increased the abundance of probiotics and butyrate level in the feces of AS mice and L.johnsonii and L.murinus were positively correlated with butyrate. Supplementation of butyrate inhibited macrophage pyroptosis and atherosclerosis in vivo. In vitro, butyrate could inhibit the expression of NLRP3/Caspase-1/IL-1β and pyroptosome production, and this process mainly by activating butyrate receptors GPR41, GPR43 and GPR109A. Conclusions The gut microbiota may mediate the anti-AS effect of aspirin by promoting an increase in the abundance of L.johnsonii and L.murinus. Butyrate produced by Lactobacillus may mediate the anti-AS effect of aspirin, and inhibiting macrophage pyroptosis and the progression of AS.

High expression of PLA2G2A in fibroblasts plays a crucial role in the early progression of carotid atherosclerosis

BackgroundIn mouse models of atherosclerosis, knockout of the PLA2G2A gene has been shown to reduce the volume of atherosclerotic plaques. Clinical trials have demonstrated the potential of using the sPLA2 inhibitor Varespladib in combination with statins to reduce lipid levels. However, this approach has not yielded the expected results in reducing the risk of cardiovascular events. Therefore, it is necessary to further investigate the mechanisms of PLA2G2A.MethodsSingle-cell transcriptome data from two sets of carotid plaques, combined with clinical patient information. were used to describe the expression characteristics of PLA2G2A in carotid plaques at different stages. In order to explore the mechanisms of PLA2G2A, we conducted enrichment analysis, cell–cell communication analysis and single-cell regulatory network inference and clustering analyses. We validated the above findings at the cellular level.ResultsOur findings indicate that PLA2G2A is primarily expressed in vascular fibroblasts and shows significant cell interactions with macrophages in the early-stage, especially in complement and inflammation-related pathways. We also found that serum sPLA2 levels have stronger diagnostic value in patients with mild carotid artery stenosis. Subsequent comparisons of single-cell transcriptomic data from early and late-stage carotid artery plaques corroborated these findings and predicted transcription factors that might regulate the progression of early carotid atherosclerosis (CA) and the expression of PLA2G2A.ConclusionsOur study discovered and validated that PLA2G2A is highly expressed by vascular fibroblasts and promotes plaque progression through the activation of macrophage complement and coagulation cascade pathways in the early-stage of CA.

Integrated metabolomics and network pharmacology to reveal the mechanisms of Shexiang Baoxin pill against atherosclerosis

BackgroundAtherosclerosis is a disease marked by the development of lipid lesions within the endothelium and continues to be a prominent contributor to global mortality. Shexiang Baoxin pill (SBP) has been employed in the management of numerous cardiovascular diseases, but the complex mechanisms by which it operates remain obscure. This research was conducted to determine the potential impact of SBP on atherosclerosis and the underlying regulatory mechanism involved. MethodNetwork pharmacology was utilized to predict the key drug-disease targets, and a nontargeted metabolomic assay was applied to identify the key metabolites and metabolic pathways. A mouse atherosclerosis model was constructed to clarify the protective effect of SBP on atherosclerosis, and in vivo and in vitro tests were performed to verify the analysis results and clarify the mechanism through which SBP affects atherosclerosis. ResultsThe results show that SBP can exert a protective effect in vivo by decreasing lipid levels, plaque formation and endothelial damage. Network pharmacology and metabolomics revealed that MAPK3, AKT1 and STAT3 were the hub targets and that trimethylamine n-oxide (TMAO) was the pivotal metabolite. Due to the atherogenic effect of TMAO, the corresponding protective effect of SBP was investigated in vitro. SBP inhibited TMAO-induced endothelial cell apoptosis and oxidative stress and counteracted the upregulation of MAPK3, AKT1, and STAT3 expression. Molecular docking and enzymatic inhibition suggested that the active components of SBP could bind stably to key target proteins. ConclusionTaken together, based on the integrated metabolomics and network pharmacology, our findings suggest that SBP may be implicated in TMAO-induced atherosclerosis by affecting endothelial function and bile acid synthesis. We observed that SBP may ameliorate atherosclerosis by regulating TMAO levels through multiple pathways, which may provide a novel direction and insight for SBP involved in cardiovascular protection by mediating the gut-heart axis.

Anti-Inflammatory Oxysterol, Oxy210, Inhibits Atherosclerosis in Hyperlipidemic Mice and Inflammatory Responses of Vascular Cells.

We previously reported that Oxy210, an oxysterol-based drug candidate, exhibits antifibrotic and anti-inflammatory properties. We also showed that, in mice, it ameliorates hepatic hallmarks of non-alcoholic steatohepatitis (NASH), including inflammation and fibrosis, and reduces adipose tissue inflammation. Here, we aim to investigate the effects of Oxy210 on atherosclerosis, an inflammatory disease of the large arteries that is linked to NASH in epidemiologic studies, shares many of the same risk factors, and is the major cause of mortality in people with NASH. Oxy210 was studied in vivo in APOE*3-Leiden.CETP mice, a humanized mouse model for both NASH and atherosclerosis, in which symptoms are induced by consumption of a high fat, high cholesterol "Western" diet (WD). Oxy210 was also studied in vitro using two cell types that are important in atherogenesis: human aortic endothelial cells (HAECs) and macrophages treated with atherogenic and inflammatory agents. Oxy210 reduced atherosclerotic lesion formation by more than 50% in hyperlipidemic mice fed the WD for 16 weeks. This was accompanied by reduced plasma cholesterol levels and reduced macrophages in lesions. In HAECs and macrophages, Oxy210 reduced the expression of key inflammatory markers associated with atherosclerosis, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), vascular cell adhesion molecule-1 (VCAM-1), and E-Selectin. In addition, cholesterol efflux was significantly enhanced in macrophages treated with Oxy210. These findings suggest that Oxy210 could be a drug candidate for targeting both NASH and atherosclerosis, as well as chronic inflammation associated with the manifestations of metabolic syndrome.

Visualizing Immune Checkpoint Inhibitors Derived Inflammation in Atherosclerosis.

Immune checkpoint inhibitor (ICI) usage has resulted in immune-related adverse events in patients with cancer, such as accelerated atherosclerosis. Of immune cells involved in atherosclerosis, the role of CCR2+ (CC motif chemokine receptor 2-positive) proinflammatory macrophages is well documented. However, there is no noninvasive approach to determine the changes of these cells in vivo following ICI treatment and explore the underlying mechanisms of immune-related adverse events. Herein, we aim to use a CCR2 (CC motif chemokine receptor 2)-targeted radiotracer and positron emission tomography (PET) to assess the aggravated inflammatory response caused by ICI treatment in mouse atherosclerosis models and explore the mechanism of immune-related adverse events. Apoe-/- mice and Ldlr-/- mice were treated with an ICI, anti-PD1 (programmed cell death protein 1) antibody, and compared with those injected with either isotype control IgG or saline. The radiotracer 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-ECL1i (extracellular loop 1 inverso) was used for PET imaging of CCR2+ macrophages. Atherosclerotic arteries were collected for molecular characterization. CCR2 PET revealed significantly higher radiotracer uptake in both Apoe-/- and Ldlr-/- mice treated with anti-PD1 compared with the control groups. The increased expression of CCR2+ cells in Apoe-/- and Ldlr-/- mice was confirmed by immunostaining and flow cytometry. Single-cell RNA sequencing revealed elevated expression of CCR2 in myeloid cells. Mechanistically, IFNγ (interferon gamma) was essential for aggravated inflammation and atherosclerotic plaque progression following anti-PD1 treatment. Accelerated atherosclerotic plaque inflammation triggered by anti-PD1 treatment can be noninvasively detected by 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-ECL1i PET. Aggravated plaque inflammation is time- and dose-dependent and predominately mediated by IFNγ signaling. This study warrants further investigation of CCR2 PET as a noninvasive approach to visualize atherosclerotic plaque inflammation and explore the underlying mechanism following ICI treatment.

Wall Shear Stress (WSS) Analysis in Atherosclerosis in Partial Ligated Apolipoprotein E Knockout Mouse Model through Computational Fluid Dynamics (CFD).

Atherosclerosis involves an inflammatory response due to plaque formation within the arteries, which can lead to ischemic stroke and heart disease. It is one of the leading causes of death worldwide, with various contributing factors such as hyperlipidemia, hypertension, obesity, diabetes, and smoking. Wall shear stress (WSS) is also known as a contributing factor of the formation of atherosclerotic plaques. Since the causes of atherosclerosis cannot be attributed to a single factor, clearly understanding the mechanisms and causes of its occurrence is crucial for preventing the disease and developing effective treatment strategies. To better understand atherosclerosis and define the correlation between various contributing factors, computational fluid dynamics (CFD) analysis is primarily used. CFD simulates WSS, the frictional force caused by blood flow on the vessel wall with various hemodynamic changes. Using apolipoprotein E knockout (ApoE-KO) mice subjected to partial ligation and a high-fat diet at 1-week, 2-week, and 4-week intervals as an atherosclerosis model, CFD analysis was conducted along with the reconstruction of carotid artery blood flow via magnetic resonance imaging (MRI) and compared to the inflammatory factors and pathological staining. In this experiment, a comparative analysis of the effects of high WSS and low WSS was conducted by comparing the standard deviation of time-averaged wall shear stress (TAWSS) at each point within the vessel wall. As a novel approach, the standard deviation of TAWSS within the vessel was analyzed with the staining results and pathological features. Since the onset of atherosclerosis cannot be explained by a single factor, the aim was to find the correlation between the thickness of atherosclerotic plaques and inflammatory factors through standard deviation analysis. As a result, the gap between low WSS and high WSS widened as the interval between weeks in the atherosclerosis mouse model increased. This finding not only linked the occurrence of atherosclerosis to WSS differences but also provided a connection to the causes of vulnerable plaques.

Simultaneously blocking ANGPTL3 and IL-1β for the treatment of atherosclerosis through lipid-lowering and anti-inflammation.

Blood lipid levels play a critical role in the progression of atherosclerosis. However, even with adequate lipid reduction, significant residual cardiovascular risk remains. Therefore, it is necessary to seek novel therapeutic strategies for atherosclerosis that can not only lower lipid levels but also inhibit inflammation simultaneously. The fusion protein FD03-IL-1Ra was designed by linking the Angiopoietin-like 3 (ANGPTL3) nanobody and human interleukin-1 receptor antagonist (IL-1Ra) sequences to a mutated human immunoglobulin gamma 1 (IgG1) Fc. This construct was transfected into HEK293 cells for expression. The purity and thermal stability of the fusion protein were assessed using SDS-PAGE, SEC-HPLC, and differential scanning calorimetry. Binding affinities of the fusion protein to ANGPTL3 and IL-1 receptor were measured using Biacore T200. The biological activity of the fusion protein was validated through in vitro experiments. The therapeutic efficacy of the fusion protein was evaluated in an ApoE-/- mouse model of atherosclerosis, including serum lipid level determination, histological analysis of aorta and aortic sinus sections, and detection of inflammatory and oxidative stress markers. ImageJ software was utilized for quantitative image analysis. Statistical analysis was performed using one-way ANOVA followed by Bonferroni post hoc test. The FD03-IL-1Ra fusion protein was successfully expressed, with no polymer formation detected, and it demonstrated good thermal and conformational stability. High affinity for both murine and human ANGPTL3 was exhibited by FD03-IL-1Ra, and it was able to antagonize hANGPTL3's inhibition of LPL activity. FD03-IL-1Ra also showed high affinity for both murine and human IL-1R, inhibiting IL-6 expression in A549 cells induced by IL-1β stimulation, as well as suppressing IL-1β-induced activity inhibition in A375.S2 cells. Our study revealed that the fusion protein effectively lowered serum lipid levels and alleviated inflammatory responses in mice. Furthermore, the fusion protein enhanced plaque stability by increasing collagen content within atherosclerotic plaques. These findings highlighted the potential of bifunctional interleukin-1 receptor antagonist and ANGPTL3 antibody fusion proteins for ameliorating the progression of atherosclerosis, presenting a promising novel therapeutic approach targeting both inflammation and lipid levels.

Fluorescence and photoacoustic (FL/PA) dual-modal probe: Responsive to reactive oxygen species (ROS) for atherosclerotic plaque imaging

Accurate and early detection of atherosclerosis (AS) is imperative for their effective treatment. However, fluorescence probes for efficient diagnosis of AS often encounter insufficient deep tissue penetration, which hinders the reliable assessment of plaque vulnerability. In this work, a reactive oxygen species (ROS) activated near-infrared (NIR) fluorescence and photoacoustic (FL/PA) dual model probe TPA-QO-B is developed by conjugating two chromophores (TPA-QI and O–OH) and ROS-specific group phenylboronic acid ester. The incorporation of ROS-specific group not only induces blue shift in absorbance, but also inhibits the ICT process of TPA-QO-OH, resulting an ignorable initial FL/PA signal. ROS triggers the convertion of TPA-QO-B to TPA-QO-OH, resulting in the concurrent amplification of FL/PA signal. The exceptional selectivity of TPA-QO-B towards ROS makes it effectively distinguish AS mice from the healthy. The NIR emission can achieve a tissue penetration imaging depth of 0.3 cm. Moreover, its PA775 signal possesses the capability to penetrate tissues up to a thickness of 0.8 cm, ensuring deep in vivo imaging of AS model mice in early stage. The ROS-triggered FL/PA dual signal amplification strategy improves the accuracy and addresses the deep tissue penetration problem simultaneously, providing a promising tool for in vivo tracking biomarkers in life science and preclinical applications.

LRG1 promotes atherosclerosis by inducing macrophage M1-like polarization

Atherosclerosis is a chronic inflammatory disease of the arterial wall characterized by the accumulation of cholesterol-rich lipoproteins in macrophages. How macrophages commit to proinflammatory polarization under atherosclerosis conditions is not clear. Report here that the level of a circulating protein, leucine-rich alpha-2 glycoprotein 1 (LRG1), is elevated in the atherosclerotic tissue and serum samples from patients with coronary artery disease (CAD). LRG1 stimulated macrophages to proinflammatory M1-like polarization through the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways. The LRG1 knockout mice showed significantly delayed atherogenesis progression and reduced levels of macrophage-related proinflammatory cytokines in a high-fat diet-induced Apoe-/- mouse atherosclerosis model. An anti-LRG1 neutralizing antibody also effectively blocked LRG1-induced macrophage M1-like polarization in vitro and conferred therapeutic benefits to animals with ApoE deficiency-induced atherosclerosis. LRG1 may therefore serve as an additional biomarker for CAD and targeting LRG1 could offer a potential therapeutic strategy for CAD patients by mitigating the proinflammatory response of macrophages.

A novel lncRNA GM47544 modulates triglyceride metabolism by inducing ubiquitination-dependent protein degradation of APOC3

ObjectiveEmerging evidence highlights the pivotal roles of long non-coding RNAs (lncRNAs) in lipid metabolism. Apoprotein C3 (ApoC3) is a well-established therapeutic target for hypertriglyceridemia and exhibits a strong association with cardiovascular disease. However, the exact mechanisms via which the lncRNAs control ApoC3 expression remain unclear. MethodsWe identified a novel long noncoding RNA (lncRNA), GM47544, within the ApoA1/C3/A4/A5 gene cluster. Subsequently, the effect of GM47544 on intracellular triglyceride metabolism was analyzed. The diet-induced mouse models of hyperlipidemia and atherosclerosis were established to explore the effect of GM47544 on dyslipidemia and plaque formation in vivo. The molecular mechanism was explored through RNA sequencing, immunoprecipitation, RNA pull-down assay, and RNA immunoprecipitation. ResultsGM47544 was overexpressed under high-fat stimulation. GM47544 effectively improved hepatic steatosis, reduced blood lipid levels, and alleviated atherosclerosis in vitro and in vivo. Mechanistically, GM47544 directly bound to ApoC3 and facilitated the ubiquitination at lysine 79 in ApoC3, thereby facilitating ApoC3 degradation via the ubiquitin-proteasome pathway. Moreover, we identified AP006216.5 as the human GM47544 transcript, which fulfills a comparable function in human hepatocytes. ConclusionsThe identification of GM47544 as a lncRNA modulator of ApoC3 reveals a novel mechanism of post-translational modification, with significant clinical implications for the treatment of hypertriglyceridemia and atherosclerosis.

Investigating the impact of doxorubicin on plaque formation in an apolipoprotein-E-deficient mouse model of atherosclerosis

Investigating the impact of doxorubicin on plaque formation in an apolipoprotein-E-deficient mouse model of atherosclerosis

Attenuation of Atherosclerosis with PAR4 Deficiency: Differential Platelet Outcomes in apoE -/- vs. Ldlr -/- Mice.

Cardiovascular disease (CVD) is a significant burden globally and, despite current therapeutics, remains the leading cause of death. Platelet inhibitors are of interest in CVD treatment to reduce thrombus formation post-plaque rupture as well their contribution to inflammation throughout the progression of atherosclerosis. Protease activated receptor 4 (PAR4) is a receptor highly expressed by platelets, strongly activated by thrombin, and plays a vital role in platelet activation and aggregation. However, the role of PAR4. Mice on a low-density lipoprotein receptor-deficient ( Ldlr -/- ) background were bred with Par4 deficient ( Par4 -/- ) mice to create Ldlr -/- /Par4 +/+ and Ldlr -/- /Par4 -/- cousin lines. Mice were fed high fat (42%) and cholesterol (0.2%) 'Western' diet for 12 weeks for all studies. Bone marrow transplant (BMT) studies were conducted by irradiating Ldlr -/- /Par4 +/+ and Ldlr -/- /Par4 -/- mice with 550 rads (2x, 4 hours apart) and then repopulated with Par4 +/+ or Par4 -/- bone marrow. To determine if the effects of thrombin were mediated solely by PAR4, the thrombin inhibitor dabigatran was added to the 'Western' diet. Ldlr -/- /Par4 -/- given dabigatran did not further decrease their atherosclerotic burden. Differences between apolipoprotein E deficient ( apoE -/- ) and Ldlr -/- platelets were assessed for changes in reactivity. We observed higher PAR4 abundance in arteries with atherosclerosis in human and mice versus healthy controls. PAR4 deficiency attenuated atherosclerosis in the aortic sinus and root versus proficient controls. BMT studies demonstrated this effect was due to hematopoietic cells, most likely platelets. PAR4 appeared to be acting independent of PAR1, as there werer no changes with addition of dabigatran to PAR4 deficient mice. apoE -/- platelets are hyperreactive compared to Ldlr -/- platelets. Hematopoietic-derived PAR4, most likely platelets, plays a vital role in the development and progression of atherosclerosis. Specific targeting of PAR4 may be a potential therapeutic target for CVD. Deficiency of protease-activated receptor 4 attenuates the development of diet-induced atherosclerosis in a Ldlr -/- mouse model. PAR4 deficiency in hematopoietic cells is atheroprotective. PAR4 deficiency accounts for the majority of thrombin-induced atherosclerosis in a Ldlr -/- mouse model. The examination of platelet-specific proteins and platelet activation should be carefully considered before using the apoE -/- or Ldlr -/- mouse models of atherosclerosis.

Abstract We052: Angiotensin-converting enzyme (ACE): A new role to regulate β-oxidation in monocytic cells

The metabolic failure of macrophages to adequately process lipid, and the deleterious effects of ingested lipid on macrophage behavior, is central to the etiology of atherosclerosis. As angiotensin-converting enzyme (ACE) has major effects on myeloid cell metabolism, we examined the role of macrophage ACE in a mouse model of atherosclerosis. Animals with increased macrophage ACE expression (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and higher levels of effector molecules downstream of PPARα. These macrophages have increased basal and maximal oxygen consumption compared to WT macrophages. When exposed to lipid in vitro, ACE 10/10 macrophages ingest more fatty acid than WT and have increased efferocytosis. ACE 10/10 macrophages metabolize via β oxidation far more fatty acid than WT cells as determined using 13C isotope tracing. In part by increasing PPARα, ACE boosts myeloid metabolic function under pathophysiologic lipid stress, addressing a key myeloid failure in atherosclerosis.

Mutagenesis on a complex mouse genetic background by site-specific nucleases.

Mouse models with complex genetic backgrounds are increasingly used in preclinical research to accurately model human disease and to enable temporal and cell-specific evaluation of genetic manipulations. Backcrossing mice onto these complex genetic backgrounds takes time and leads to significant wastage of animals. In this study, we aimed to evaluate whether site-specific nucleases could be used to generate additional genetic mutations in a complex genetic background, using the REVERSA mouse model of atherosclerosis, a model harbouring four genetically altered alleles. The model is comprised of a functional null mutation in the Ldlr gene in combination with a ApoB100 allele, which, after high-fat diet, leads to the rapid development of atherosclerosis. The regression of the pathology is achieved by inducible knock-out of the Mttp gene. Here we report an investigation to establish if microinjection of site-specific nucleases directly into zygotes prepared from the REVERSA could be used to investigate the role of the ATP binding cassette transporter G1 (ABCG1) in atherosclerosis regression. We show that using this approach we could successfully generate two independent knockout lines on the REVERSA background, both of which exhibited the expected phenotype of a significant reduction in cholesterol efflux to HDL in bone marrow-derived macrophages. However, loss of Abcg1 did not impact atherosclerosis regression in either the aortic root or in aortic arch, demonstrating no important role for this transporter subtype. We have demonstrated that site-specific nucleases can be used to create genetic modifications directly onto complex disease backgrounds and can be used to explore gene function without the need for laborious backcrossing of independent strains, conveying a significant 3Rs advantage.

Cross-species single-cell RNA sequencing reveals divergent phenotypes and activation states of adaptive immunity in human carotid and experimental murine atherosclerosis.

The distinct functions of immune cells in atherosclerosis have been mostly defined by preclinical mouse studies. Contrastingly, the immune cell composition of human atherosclerotic plaques and their contribution to disease progression is only poorly understood. It remains uncertain whether genetic animal models allow for valuable translational approaches. Single cell RNA-sequencing (scRNA-seq) was performed to define the immune cell landscape in human carotid atherosclerotic plaques. The human immune cell repertoire demonstrated an unexpectedly high heterogeneity and was dominated by cells of the T-cell lineage, a finding confirmed by immunohistochemistry. Bioinformatical integration with 7 mouse scRNA-seq data sets from adventitial and atherosclerotic vascular tissue revealed a total of 51 identities of cell types and differentiation states, of which some were only poorly conserved between species and exclusively found in humans. Locations, frequencies, and transcriptional programs of immune cells in mouse models did not resemble the immune cell landscape in human carotid atherosclerosis. In contrast to standard mouse models of atherosclerosis, human plaque leukocytes were dominated by several T-cell phenotypes with transcriptional hallmarks of T-cell activation and memory formation, T-cell receptor-, and pro-inflammatory signaling. Only mice at the age of 22 months partially resembled the activated T-cell phenotype. In a validation cohort of 43 patients undergoing carotid endarterectomy, the abundance of activated immune cell subsets in the plaque defined by multi-color flow cytometry associated with the extend of clinical atherosclerosis. Integrative scRNA-seq reveals a substantial difference in the immune cell composition of murine and human carotid atherosclerosis - a finding that questions the translational value of standard mouse models for adaptive immune cell studies. Clinical associations suggest a specific role for T-cell driven (auto-) immunity in human plaque formation and -instability.

Mechanism of astragaloside Ⅳ modulation of Nrf2/HO-1/GPX4 pathway to inhibit ferroptosis and ameliorate atherosclerosis in ApoE~(-/-) mice

The intervention effect of astragaloside Ⅳ(AS-Ⅳ) on atherosclerosis in apolipoprotein E gene knockout(ApoE)~(-/-) mice was observed based on the nuclear factor erythroid-2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)/glutathione peroxidase 4(GPX4) signaling pathway to explore the potential mechanism of AS-Ⅳ in improving ferroptosis in atherosclerotic mice. This study established an atherosclerosis mouse model by feeding them a high-fat diet. After modeling for 8 weeks, ApoE~(-/-) mice were randomly divided into the model group, AS-Ⅳ group, AS-Ⅳ+Nrf2 inhibitor(ML385) group, and ferrostatin-1(Fer-1) group. Additionally, a blank control group was also established. Corresponding drugs were administered via intraperitoneal injection, with the control group receiving an equivalent amount of normal saline injection as the model group. After the experiment, serum biochemical levels were measured using an automatic blood lipid analyzer, hematoxylin-eosin(HE) staining was used to observe morphological changes in aortic sinus tissues, colorimetric methods were used to detect levels of ferrous ion(Fe~(2+)), malondialdehyde(MDA), glutathione(GSH), and superoxide dismutase(SOD) in mouse serum, immunofluorescence was used to observe the expressions of ferritin heavy chain 1(FTH1) and ferritin light chain(FTL) proteins in the aortic sinus of mice, Western blot was used to detect the protein levels of Nrf2, HO-1, and GPX4 in mouse aortic tissues, and transmission electron microscopy was used to observe ultrastructural changes in aortic tissues. RESULTS:: showed that compared to the control group, the model group of mice had significantly increased calcification and plaque deposition areas in the aortic sinus, increased mitochondrial membrane density, decreased or disappeared mitochondrial cristae, elevated levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), Fe~(2+), and MDA, decreased levels of high-density lipoprotein cholesterol(HDL-C), SOD, and GSH, and significant inhibition of Nrf2, HO-1, GPX4 proteins, as well as iron storage proteins FTH1 and FTL expressions in the aorta. Compared to the model group, AS-Ⅳ treatment resulted in decreased serum TC, TG, LDL-C, Fe~(2+), and MDA levels, increased HDL-C, SOD, and GSH levels, increased expressions of Nrf2, HO-1, and GPX4 proteins, and iron storage proteins FTH1 and FTL, and significant improvement in aortic tissue morphology. Compared to the AS-Ⅳ group, the Nrf2 inhibitor ML385 could reverse the therapeutic effect of AS-Ⅳ on atherosclerosis mice. These findings suggest that AS-Ⅳ can inhibit ferroptosis and improve atherosclerosis in ApoE~(-/-) mice, and its mechanism of action may be related to the regulation of the Nrf2/HO-1/GPX4 signaling pathway.

Novel Mouse Model of Myocardial Infarction, Plaque Rupture, and Stroke Shows Improved Survival With Myeloperoxidase Inhibition.

Thromboembolic events, including myocardial infarction (MI) or stroke, caused by the rupture or erosion of unstable atherosclerotic plaques are the leading cause of death worldwide. Although most mouse models of atherosclerosis develop lesions in the aorta and carotid arteries, they do not develop advanced coronary artery lesions. Moreover, they do not undergo spontaneous plaque rupture with MI and stroke or do so at such a low frequency that they are not viable experimental models to study late-stage thrombotic events or to identify novel therapeutic approaches for treating atherosclerotic disease. This has stymied the development of more effective therapeutic approaches for reducing these events beyond what has been achieved with aggressive lipid lowering. Here, we describe a diet-inducible mouse model that develops widespread advanced atherosclerosis in coronary, brachiocephalic, and carotid arteries with plaque rupture, MI, and stroke. We characterized a novel mouse model with a C-terminal mutation in the scavenger receptor class B, type 1 (SR-BI), combined with Ldlr knockout (designated SR-BI∆CT/∆CT/Ldlr-/-). Mice were fed Western diet (WD) for 26 weeks and analyzed for MI and stroke. Coronary, brachiocephalic, and carotid arteries were analyzed for atherosclerotic lesions and indices of plaque stability. To validate the utility of this model, SR-BI∆CT/∆CT/Ldlr-/- mice were treated with the drug candidate AZM198, which inhibits myeloperoxidase, an enzyme produced by activated neutrophils that predicts rupture of human atherosclerotic lesions. SR-BI∆CT/∆CT/Ldlr-/- mice show high (>80%) mortality rates after 26 weeks of WD feeding because of major adverse cardiovascular events, including spontaneous plaque rupture with MI and stroke. Moreover, WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice displayed elevated circulating high-sensitivity cardiac troponin I and increased neutrophil extracellular trap formation within lesions compared with control mice. Treatment of WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice with AZM198 showed remarkable benefits, including >90% improvement in survival and >60% decrease in the incidence of plaque rupture, MI, and stroke, in conjunction with decreased circulating high-sensitivity cardiac troponin I and reduced neutrophil extracellular trap formation within lesions. WD-fed SR-BI∆CT/∆CT/Ldlr-/- mice more closely replicate late-stage clinical events of advanced human atherosclerotic disease than previous models and can be used to identify and test potential new therapeutic agents to prevent major adverse cardiac events.

Plexin D1 negatively regulates macrophage-derived foam cell migration via the focal adhesion kinase/Paxillin pathway

BackgroundMacrophage-derived foam cell formation is a hallmark of atherosclerosis and is retained during plaque formation. Strategies to inhibit the accumulation of these cells hold promise as viable options for treating atherosclerosis. Plexin D1 (PLXND1), a member of the Plexin family, has elevated expression in atherosclerotic plaques and correlates with cell migration; however, its role in macrophages remains unclear. We hypothesize that the guidance receptor PLXND1 negatively regulating macrophage mobility to promote the progression of atherosclerosis. MethodsWe utilized a mouse model of atherosclerosis based on a high-fat diet and an ox-LDL- induced foam cell model to assess PLXND1 levels and their impact on cell migration. Through western blotting, Transwell assays, and immunofluorescence staining, we explored the potential mechanism by which PLXND1 mediates foam cell motility in atherosclerosis. ResultsOur study identifies a critical role for PLXND1 in atherosclerosis plaques and in a low-migration capacity foam cell model induced by ox-LDL. In the aortic sinus plaques of ApoE−/− mice, immunofluorescence staining revealed significant upregulation of PLXND1 and Sema3E, with colocalization in macrophages. In macrophages treated with ox-LDL, increased expression of PLXND1 led to reduced pseudopodia formation and decreased migratory capacity. PLXND1 is involved in regulating macrophage migration by modulating the phosphorylation levels of FAK/Paxillin and downstream CDC42/PAK. Additionally, FAK inhibitors counteract the ox-LDL-induced migration suppression by modulating the phosphorylation states of FAK, Paxillin and their downstream effectors CDC42 and PAK. ConclusionOur findings indicate that PLXND1 plays a role in regulating macrophage migration by modulating the phosphorylation levels of FAK/Paxillin and downstream CDC42/PAK to promoting atherosclerosis.

Development of a PCSK9-targeted nanoparticle vaccine to effectively decrease the hypercholesterolemia

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the low-density lipoprotein receptor (LDLR) and mediates its internalization and degradation, resulting in an increase in LDL cholesterol levels. Recently, PCSK9 emerged as a therapeutic target for hypercholesterolemia and atherosclerosis. In this study, we develop a PCSK9 nanoparticle (NP) vaccine by covalently conjugating the catalytic domain (aa 153-aa 454, D374Y) of PCSK9 to self-assembled 24-mer ferritin NPs. We demonstrate that the PCSK9 NP vaccine effectively induces interfering antibodies against PCSK9 and reduces serum lipids levels in both a high-fat diet-induced hypercholesterolemia model and an adeno-associated virus-hPCSK9D374Y-induced hypercholesterolemia model. Additionally, the vaccine significantly reduces plaque lesion areas in the aorta and macrophages infiltration in an atherosclerosis mouse model. Furthermore, we discover that the vaccine's efficacy relied on T follicular help cells and LDLR. Overall, these findings suggest that the PCSK9 NP vaccine holds promise as an effective treatment for hypercholesterolemia and atherosclerosis.