Search Results (103)

Atherosclerosis is a chronic inflammatory disease and a major pathological basis of numerous cardiovascular conditions, with a high global mortality rate. Macrophages play a pivotal role in its pathogenesis through phenotypic switching and foam cell formation. Prostaglandin E2 receptor subtype 4 (EP4) highly expressed on the macrophage surface, is involved in various pathophysiological processes, such as inflammation and lipid metabolism. However, the role of macrophage EP4 in the progression of atherosclerosis remains unclear. To determine whether macrophage EP4 affects the progression of atherosclerosis by regulating foam cell formation and macrophage polarization. Myeloid-specific EP4 knockout mice with an ApoE-deficient background were fed a Western diet for 16 weeks. Our results showed that EP4 expression was significantly downregulated during atherosclerosis. EP4 deficiency was found to exacerbate atherosclerotic plaque formation and destabilizes plaques. In vitro studies further demonstrated that loss of EP4 in myeloid cells promoted foam cell formation and M1 macrophage polarization. Both transcriptomic and proteomic analysis showed that EP4 may regulate these processes by regulating CD36 expression in macrophage, which was further confirmed by Western blot and qPCR. In summary, deficiency of EP4 receptor in macrophages enhance foam cell formation and M1 polarization by upregulating CD36 expression, thereby accelerating the progression of atherosclerosis. Full article

The cellular prion protein (PrP^C) is studied in prion diseases, where its misfolded isoform (PrP^Sc) leads to neurodegeneration. PrP^C has also been implicated in several physiological functions. The protein is abundant in the nervous system, and it is critical for cell signaling in cellular communication, where it acts as a scaffold for various signaling molecules. The Reelin signaling pathway, implicated both in Alzheimer’s and prion diseases, engages Dab1, an adaptor protein influencing APP processing and amyloid beta deposition. Here, we show, using Prnp knockout models (Prnp^0/0), that PrP^C modulates Reelin signaling, affecting Dab1 activation and downstream phosphorylation in both neuronal cultures and mouse brains. Notably, Prnp^0/0 mice showed reduced responsiveness to Reelin, associated with altered Dab1 phosphorylation and Fyn kinase activity. Even though no direct interaction between PrP^C and Reelin/ApoER2 was found, Prnp^0/0 neurons showed lower NCAM levels, a well-established PrP^C interactor. Prion infection further disrupted the Reelin signaling pathway, thus downregulating Dab1 and Reelin receptors and altering Reelin processing, like Alzheimer’s disease pathology. These findings emphasize PrP^C indirect role in Dab1 signaling via the NCAM and Fyn pathways, which influence synaptic function and neurodegeneration in prion diseases. Full article

Environmental pollution significantly exacerbates various diseases, particularly those affecting the cardiovascular and respiratory systems. Our previous studies have shown that acrolein, an environmental pollutant, promotes atherosclerosis by downregulating the circadian clock genes (CLOCK/BMAL1) and disrupting circadian rhythm. We have also found that intermittent fasting (IF), closely linked to the circadian clock, may mitigate atherosclerosis induced by acrolein. Ferroptosis, a newly identified form of regulated cell death, is associated with the acceleration of atherosclerotic development, but its relationship with the circadian clock is not well understood. In this study, we explored the potential of IF to alleviate ferroptosis by modulating the circadian clock. Our in vivo experiments revealed that IF reversed ferroptosis and upregulated CLOCK/BMAL1 in APOE-/- mice. In human umbilical vein endothelial cells (HUVECs), we discovered that acrolein-induced ferroptosis leads to cell death, while short-term starvation (STS, IF cell model) reversed this effect. Acrolein also suppressed the expression of AMP-activated protein kinase (AMPK), nuclear factor erythroid 2-related factor 2 (NRF2), and CLOCK/BMAL1, which were restored by subsequent STS treatments. Additionally, the overexpression of CLOCK/BMAL1 mitigated ferroptosis, consistent with findings from CLOCK gene knockout experiments. Notably, CLOCK/BMAL1 and AMPK/NRF2 were found to be mutually regulated. Concurrently, the AMPK and NRF2 signaling pathways may be interdependent and act in concert. In conclusion, our findings suggest that IF modulates the CLOCK/BMAL1-AMPK/NRF2 pathway to alleviate acrolein-induced ferroptosis, offering a potential strategy to address health issues related to environmental pollution. Full article

Atherosclerosis, which has important effects on the development of cardiovascular diseases, is a widespread health problem with the highest mortality rate globally. In this study, we aimed to assess the impact of water and ethanolic extracts of propolis on oxidized low-density lipoprotein (OxLDL) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the progression of the atherosclerotic process, which is characterized by oxidative stress, inflammation, and dyslipidemia. In our study, apolipoprotein E knockout (ApoE^−/−) and C57BL/6J mice were used as study groups. Water (WEP) and ethanolic extracts (EEP) of propolis were administered intraperitoneally to ApoE^−/− and C57BL/6J mice modeled with a high-fat diet. Under anesthesia, the animals were euthanized by decapitation, and serum, along with aortic tissues, was collected. Serum total cholesterol (TC), triglyceride (TG), OxLDL and LOX-1 levels, OxLDL levels in aortic tissue homogenate, and subendothelial lipid accumulation levels by histological staining were determined in mice and statistical analyses were performed. WEP and EEP supplementation significantly decreased serum TC, TG, OxLDL, LOX-1, and tissue OxLDL levels and reduced plaque burden in the aortic root, with statistically significant differences observed. Those results suggest that propolis extracts have a potential treatment option for atherosclerosis, as a food supplement or a complementary medical/functional food. However, further research is needed to elucidate their molecular mechanisms, evaluate clinical efficacy and safety, and explore possible synergistic effects with existing atherosclerosis treatments. Full article

Background/Objective: Atherosclerosis is one of the leading causes of cardiovascular diseases and mortality around the world. One exciting strategy for atherosclerosis treatment is immunotherapy, especially active immunization. Active immunization relies on the delivery of antigens in a vaccine platform to introduce humoral and cellular immunity, alleviating atherosclerotic progression. Transient receptor potential channel isoform M2 (TRPM2) is an ROS-activated Ca²⁺-permeable ion channel that can promote atherosclerosis via stimulating vascular inflammation. In the present study, we developed a strategy of active immunization with the TRPM2 E3 domain peptide in a vaccine platform, aiming to induce the endogenous production of anti-TRPM2 blocking antibody in mice in vivo, consequently inhibiting TRPM2 channel activity to alleviate atherosclerotic progression. Methods: ApoE knockout mice were fed with a high cholesterol diet to develop atherosclerosis. The mice were injected with or without the E3 peptide vaccines, followed by analysis of atherosclerotic lesion by en face Oil Red O staining of the whole aorta and histologic analysis of thin tissue sections from aortic roots. Results: The results show that immunization with a pig TRPM2 E3 region-based peptide (P1) could effectively alleviate high cholesterol diet-induced atherosclerosis in ApoE knockout mice. We worked out the best vaccine formulation for the most effective atheroprotection, namely P1 at the dose of 67.5 µg per mouse (2.5 mg/kg body weight) with aluminum salts as adjuvant. Conclusions: The present study provides a novel target TRPM2 for peptide vaccine-based anti-atherosclerotic strategy and lays the foundation for future preclinical/clinical trials using TRPM2 E3 P1 vaccine for a potential therapeutic option against atherosclerosis. Full article

Background: Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are intermediary products in NAD+ metabolism. NMN and NR supplementation can elevate NAD+ levels in tissues, addressing health issues associated with aging and obesity. However, the impact of NMN and NR on atherosclerosis remains incompletely elucidated. Methods: C57BL/6J and Apolipoprotein E knockout (ApoE^−/−) mice were used to explore the impact of NMN and NR supplementation on serum lipids, fatty liver, and atherosclerosis. Additionally, various suppliers, administration protocols, and doses on ApoE^−/− mice were investigated. Results: The intragastric administration of NMN (300 mg/kg) and NR (230 mg/kg) reduced body weight, serum lipids, and fatty liver but aggravated atherosclerosis in ApoE^−/− mice after 4 months of administration with different suppliers. Atherosclerosis also deteriorated after 2 months of different NMN administration protocols (intragastric and water administration) in ApoE^−/− mice with existing plaques. The effects of NMN were dose-dependent, and doses around 100 mg/kg had little harmful effects on atherosclerosis. Conclusions: NMN and NR improve dyslipidemia and fatty liver but promote atherosclerosis in ApoE^−/− mice. These findings emphasize the safe dosage for the clinical trials of NMN. Full article

Objective: In this study, we aimed to evaluate the potential effects of white tea (WT) in the atherosclerosis process characterized by oxidative stress, inflammation, and dyslipidemia. Methods: In our study, apolipoprotein E knockout (ApoE^−/−) mice (RRID: IMSR_JAX:002052) and C57BL/6J mice (RRID: IMSR_JAX:000664) were used. In the atherosclerosis model induced by an atherogenic diet (AD), WT was administered via oral gavage at two different concentrations. The animals were sacrificed by decapitation under anesthesia, and their serum and aortic tissues were collected. Total cholesterol (TC), triglyceride (TG), interleukin (IL)-1β, IL-6, IL-10, IL-12, tumor necrosis factor-α (TNF-α), interferon-γ, myeloperoxidase, paraoxonase-1, lipoprotein-associated phospholipase A2, oxidized low-density lipoprotein (Ox-LDL), lectin-like oxidized LDL receptor (LOX-1), a disintegrin, and metalloprotease (ADAM) 10 and 17 activities were determined via colorimetric, enzyme-linked immunoassay, and fluorometric methods. Results: WT supplementation decreased serum Ox-LDL, LOX-1, TC, and TG levels by approximately 50%. TNF- and IL-6 levels were reduced by approximately 30% in the aortic arch. In addition, ADAM10/17 enzyme activities were found to be reduced by approximately 25%. However, no change in the AD-induced fibrotic cap structure was observed in the aortic root. Conclusions: The findings indicate that white tea effectively reduced oxidative stress, inflammation, and dyslipidemia in atherosclerosis but does not affect atheroma plaque morphology. Full article

Background: In recent decades, a significant global increase in the incidence of non-melanoma skin cancer has been observed. To explore the pathogenesis of and potential therapeutic approaches for squamous cell carcinoma, various in vivo studies using mouse models have been conducted. However, investigations comparing different hairless mouse models, with or without melanin, as well as models with hypercholesterolemia and immunosuppression, in terms of their ability to induce squamous cell carcinoma have yet to be undertaken. Methods: Four mouse strains, namely SKH-hr1, SKH-hr2, SKH-hr2+ApoE, and immunodeficient Nude (Foxn1 knockout), were exposed to UVA and UVB radiation three times per week, initially to 1 Minimal Erythemal Dose (MED), incrementally increased weekly to a maximum dose of 3 MED. Clinical evaluation, photodocumentation, and biophysical parameters were monitored, along with proteasome protein activity and histopathological assessments. Results: The SKH-hr1 model primarily developed actinic keratosis without significant progression to invasive squamous cell carcinoma (SCC), while the SKH-hr2 and SKH-hr2+ApoE models exhibited a higher likelihood and intensity of papilloma and aggressive SCC formation, with the latter showing upregulated proteasome activity. Histopathological analysis confirmed the presence of poorly differentiated, invasive SCCs in the SKH-hr2 and SKH-hr2+ApoE models, contrasting with the less aggressive SCCs in the Nude mice and the mixed lesions observed in the SKH-hr1 mice. Conclusions: The SKH-hr2+ApoE and SKH-hr2 mice were identified as the most suitable for further exploration of squamous cell carcinogenesis. In contrast, the SKH-hr1 mice were found to be the least suitable, even though they are albino. Notably, proteasome analysis revealed a potential role of proteasome activity in squamous cell carcinogenesis. Full article

Shear stress is one of the major hemodynamic forces acting on the endothelium. However, it is not well known how endothelial cells (EC) respond mechanically to these stimuli in vivo. Here we investigated whether changes in biomechanics properties and shear stress could increase cell susceptibility to injury, contributing to vascular fragility. We surgically implanted a shear stress modifier device on the carotid artery of ApoE-knockout mice (ApoE^−/−), which, due to its shape, causes a gradual stenosis in the vessel, resulting in distinct shear stress patterns. Our data show actin fibers accumulation in areas with higher lipid deposition in ApoE^−/−, indicating that dyslipidemia might interfere with EC actin cytoskeleton organization. We also showed that both shear stress and dyslipidemia were important for EC susceptibility to injury. Furthermore, lysosomal distribution, an important organelle for plasma membrane repair, was altered in ApoE^−/−, which could compromise EC’s ability to repair from damage. Therefore, dyslipidemia and variations in shear stress patterns not only affect cellular mechanics by compromising the actin cytoskeleton organization, but also enhance cell susceptibility to injury and alter vesicle trafficking in vascular cells. This may likely contribute to vascular fragility and thus to the initial steps of atherosclerosis development. Full article

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. Full article

Atherosclerosis (AS) has become the leading cause of cardiovascular disease worldwide. Our previous study had observed that Nippostrongylus brasiliensis (Nb) infection or its derived products could inhibit AS development by inducing an anti-inflammatory response. We performed a metabolic analysis to screen Nb-derived metabolites with anti-inflammation activity and evaluated the AS-prevention effect. We observed that the metabolite uridine had higher expression levels in mice infected with the Nb and ES (excretory–secretory) products and could be selected as a key metabolite. ES and uridine interventions could reduce the pro-inflammatory responses and increase the anti-inflammatory responses in vitro and in vivo. The apolipoprotein E gene knockout (ApoE^−/−) mice were fed with a high-fat diet for the AS modeling. Following the in vivo intervention, ES products or uridine significantly reduced serum and liver lipid levels, alleviated the formation of atherosclerosis, and reduced the pro-inflammatory responses in serum or plaques, while the anti-inflammatory responses showed opposite trends. After blocking with 5-HD (5-hydroxydecanoate sodium) in vitro, the mRNA levels of M2 markers were significantly reduced. When blocked with 5-HD in vivo, the degree of atherosclerosis was worsened, the pro-inflammatory responses were increased compared to the uridine group, while the anti-inflammatory responses decreased accordingly. Uridine, a key metabolite from Nippostrongylus brasiliensis, showed anti-inflammatory and anti-atherosclerotic effects in vitro and in vivo, which depend on the activation of the mitochondrial ATP-sensitive potassium channel. Full article

Background: The discovery of traditional plants’ medicinal and nutritional properties has opened up new avenues for developing pharmaceutical and dietary strategies to prevent atherosclerosis. However, the effect of the antioxidant Dendrobium officinale polysaccharide (DOP) on atherosclerosis is still not elucidated. Purpose: This study aims to investigate the inhibitory effect and the potential mechanism of DOP on high-fat diet-induced atherosclerosis in Apolipoprotein E knockout (ApoE^−/−) mice. Study design and methods: The identification of DOP was measured by high-performance gel permeation chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR). We used high-fat diet (HFD)-induced atherosclerosis in ApoE^−/− mice as an animal model. In the DOP intervention stage, the DOP group was treated by gavage with 200 μL of 200 mg/kg DOP at regular times each day and continued for eight weeks. We detected changes in serum lipid profiles, inflammatory factors, anti-inflammatory factors, and antioxidant capacity to investigate the effect of the DOP on host metabolism. We also determined microbial composition using 16S rRNA gene sequencing to investigate whether the DOP could improve the structure of the gut microbiota in atherosclerotic mice. Results: DOP effectively inhibited histopathological deterioration in atherosclerotic mice and significantly reduced serum lipid levels, inflammatory factors, and malondialdehyde (F/B) production. Additionally, the levels of anti-inflammatory factors and the activity of antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), were significantly increased after DOP intervention. Furthermore, we found that DOP restructures the gut microbiota composition by decreasing the Firmicutes/Bacteroidota (F/B) ratio. The Spearman’s correlation analysis indicated that serum lipid profiles, antioxidant activity, and pro-/anti-inflammatory factors were associated with Firmicutes, Bacteroidota, Allobaculum, and Coriobacteriaceae_UCG-002. Conclusions: This study suggests that DOP has the potential to be developed as a food prebiotic for the treatment of atherosclerosis in the future. Full article

Lipid metabolism participates in various physiological processes and has been shown to be connected to the development and progression of multiple diseases, especially metabolic hepatopathy. Apolipoproteins (Apos) act as vectors that combine with lipids, such as cholesterol and triglycerides (TGs). Despite being involved in lipid transportation and metabolism, the critical role of Apos in the maintenance of lipid metabolism has still not been fully revealed. This study sought to clarify variations related to m6A methylome in ApoF gene knockout mice with disordered lipid metabolism based on the bioinformatics method of transcriptome-wide m6A methylome epitranscriptomics. High-throughput methylated RNA immunoprecipitation sequencing (MeRIP-seq) was conducted in both wild-type (WT) and ApoF knockout (KO) mice. As a result, the liver histopathology presented vacuolization and steatosis, and the serum biochemical assays reported abnormal lipid content in KO mice. The m6A-modified mRNAs were conformed consensus sequenced in eukaryotes, and the distribution was enriched within the coding sequences and 3′ non-coding regions. In KO mice, the functional annotation terms of the differentially expressed genes (DEGs) included cholesterol, steroid and lipid metabolism, and lipid storage. In the differentially m6A-methylated mRNAs, the functional annotation terms included cholesterol, TG, and long-chain fatty acid metabolic processes; lipid transport; and liver development. The overlapping DEGs and differential m6A-modified mRNAs were also enriched in terms of lipid metabolism disorder. In conclusion, transcriptome-wide MeRIP sequencing in ApoF KO mice demonstrated the role of this crucial apolipoprotein in liver health and lipid metabolism. Full article

Apolipoprotein E-knockout (Apoe-/-) mice constitute the most widely employed animal model of atherosclerosis. Deletion of Apoe induces profound hypercholesterolemia and promotes the development of atherosclerosis. However, despite its widespread use, the Apoe-/- mouse model remains incompletely characterized, especially at late time points and advanced disease stages. Thus, it is unclear how late atherosclerotic plaques compare to earlier ones in terms of lipid deposition, calcification, macrophage accumulation, smooth muscle cell presence, or plaque necrosis. Additionally, it is unknown how cardiac function and hemodynamic parameters are affected at late disease stages. Here, we used a comprehensive analysis based on histology, fluorescence microscopy, and Doppler ultrasonography to show that in normal chow diet-fed Apoe-/- mice, atherosclerotic lesions at the level of the aortic valve evolve from a more cellular macrophage-rich phenotype at 26 weeks to an acellular, lipid-rich, and more necrotic phenotype at 52 weeks of age, also marked by enhanced lipid deposition and calcification. Coronary artery atherosclerotic lesions are sparse at 26 weeks but ubiquitous and extensive at 52 weeks; yet, left ventricular function was not significantly affected. These findings demonstrate that atherosclerosis in Apoe-/- mice is a highly dynamic process, with atherosclerotic plaques evolving over time. At late disease stages, histopathological characteristics of increased plaque vulnerability predominate in combination with frequent and extensive coronary artery lesions, which nevertheless may not necessarily result in impaired cardiac function. Full article

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. Full article