Allicin induces the upregulation of ABCA1 expression via PPARγ/LXRα signaling in THP-1 macrophage-derived foam cells

Polystyrene nano-plastics impede skeletal muscle development and induce lipid accumulation via the PPARγ/LXRβ pathway in vivo and in vitro in mice

Nano-plastics (NPs) have emerged as a significant environmental pollutant, widely existing in water environment, and pose a serious threat to health and safety with the intake of animals. Skeletal muscle, a vital organ for complex life activities and functional demands, has received limited attention regarding the effects of NPs. In this study, the effects of polystyrene NPs (PS-NPs) on skeletal muscle development were studied by oral administration of different sizes (1 mg/kg) of PS-NPs in mice. The findings revealed that PS-NPs resulted in skeletal muscle damage and significantly hindered muscle differentiation, exhibiting an inverse correlation with PS-NPs particle size. Morphological analysis demonstrated PS-NPs caused partial disruption of muscle fibers, increased spacing between fibers, and lipid accumulation. RT-qPCR and western blots analyses indicated that PS-NPs exposure downregulated the expression of myogenic differentiation-related factors (Myod, Myog and Myh2), activated PPARγ/LXRβ pathway, and upregulated the expressions of lipid differentiation-related factors (SREBP1C, SCD-1, FAS, ACC1, CD36/FAT, ADIPOQ, C/EBPα and UCP-1). In vitro experiments, C2C12 cells were used to confirm cellular penetration of PS-NPs (0, 100, 200, 400 μg/mL) through cell membranes along with activation of PPARγ expression. Furthermore, to verify LXRβ as a key signaling molecule, silencing RNA transfection experiments were conducted, resulting in no increase in the expressions of PPARγ, LXRβ, SREBP1C, FAS, CD36/FAT, ADIPOQ, C/EBPα and UCP-1 even after exposure to PS-NPs. However, the expressions of SCD-1and ACC1 remained unaffected. The present study evidenced that exposure to PS-NPs induced lipid accumulation via the PPARγ/LXRβ pathway thereby influencing skeletal muscle development.

An in-depth examination of Per- and Polyfluoroalkyl (PFAS) effects on transporters, with emphasis on the ABC superfamily: A critical review

Per- and polyfluoroalkyl (PFAS) substances are a type of chemical compound unique for their multiple carbon-fluorine bonds, imbuing them with strength and environmental permanence. While legacy substances have been phased out due to human health risks, short-chain and alternative PFAS remain omnipresent. However, a detailed explanation for the pathways through which PFAS interact on a cellular and molecular level is still largely unknown, and the human health effects remain mechanistically unexplained. Of particular interest when focusing on this topic are the interactions between these exogenous chemicals and plasma and membrane proteins. Such proteins include serum albumin which can transport PFAS throughout the body, solute carrier proteins (SLC) and ATP binding cassette (ABC) transporters which are able to move PFAS into and out of cells, and proteins and nuclear receptors which interact with PFAS intracellularly. ABC transporters as a family have little available human data despite being responsible for the export of endogenous substances and drugs throughout the body. The multifactorial regulation of these crucial transporters is affected directly and indirectly by PFAS. Changes, which can include alterations to membrane transport activity and differences in protein expression, vary greatly depending on the specific PFAS and protein of interest. Together, the myriad of changes caused by understudied PFAS exposure to a class of understudied proteins crucial to cellular function and drug treatments has not been fully explored regarding human health and presents room for further exploration. This critical work aims to provide a novel framework of existing human data on PFAS and ABC transporters, allowing for future advancement and investigation into human transporter activity, mechanisms of regulation, and interactions with emerging contaminants.

Targeting Mitochondrial Cholesterol Efflux via TCF21/ABCA10 Pathway to Enhance Cisplatin Efficacy in Ovarian Cancer

Cisplatin (DDP) resistance is one of the causes of treatment failure for ovarian cancer (OV). Mitochondrial cholesterol level was reported to be associated with OV chemoresistance. We found that ABCA10, a potential cholesterol transport protein, was highly expressed in ovarian tissues and downregulated in OV tissues. Our study aimed to explore TCF21/ABCA10 axis resistance to DDP therapy in ovarian cancer based on regulating mitochondrial cholesterol efflux. Thirty epithelial ovarian cancer tumors and thirty ovarian tissues from non-cancer patients were collected. Western blot and RT-qPCR were used to measure ABCA10 and TCF21 expression levels in these tissues, as well as in a human ovarian epithelial cell line (IOSE-80), OV cells (A2780 and SKOV3), and DDP-resistant OV cell lines (A2780/DDP and SKOV3/DDP). IOSE-80 cells were also infected with ABCA10 knockdown lentivirus to identify the most effective ABCA10 knockdown plasmid. Lentiviral infection was used to create ABCA10 knockdown, ABCA10 overexpression, and TCF21 overexpression anti-DDP OV cell lines. Cell proliferation was detected by CCK-8 and EDU staining, flow cytometry for apoptosis, MTT for metabolic activity, calcium-induced Cytochrome C release, and mitochondrial matrix swelling for mitochondrial function and Oil Red O staining for lipid accumulation. Cholesterol metabolism was evaluated by measuring mitochondrial cholesterol and cholesterol efflux. Protein concentration was determined using the BCA method. A dual-luciferase reporter assay confirmed TCF21's interaction with ABCA10. ChIP also verified this interaction. The mRNA level (P < 0.01) and protein level (P < 0.001) of ABCA10 were downregulated in cancer tissues of OV patients relative to normal ovarian tissues. Relative to human ovarian epithelial cells, ABCA10 expression was significantly downregulated in OV cells (P < 0.01) and even more significantly downregulated in DDP-resistant OV cells (P < 0.001). Compared to the group treated solely with DDP, the overexpression of ABCA10 significantly inhibited the proliferation of DDP-resistant OV cells (P < 0.01), markedly reduced the staining intensity of EDU in these cells (P < 0.05), and substantially accelerated apoptosis in DDP-resistant OV cells (P < 0.01).Overexpression of ABCA10 further accelerated Cytochrome C expression and mitochondrial matrix swelling in DDP-resistant OV cells compared to the DDP-alone group (P < 0.01). The addition of cholesterol reversed the decrease in lipid accumulation, the decrease in mitochondrial cholesterol levels (P < 0.05), and the increase in cholesterol efflux (P < 0.01) in DDP-resistant OV cells caused by overexpression of ABCA10. The transcription factor TCF21 was bound to the promoter of ABCA10. Overexpression of TCF21 significantly increased ABCA10 expression in DDP-resistant OV cells (P < 0.01) and increased cytochrome C expression in A2780/DDP (P < 0.05) and SKOV3/DDP (P < 0.01) cells, with accelerated mitochondrial matrix swelling in A2780/DDP (P < 0.01) and SKOV3/DDP (P < 0.001) cells, while knockdown of ABCA10 reversed these effects. Our study found that TCF21 boosts ABCA10 expression, which in turn reduces DDP resistance in OV cells by enhancing mitochondrial cholesterol efflux. This mechanism increases the sensitivity of DDP-resistant OV cells to DDP. Our findings will provide new therapeutic targets for the treatment of ovarian cancer.

Identifying atheroprotective fruits and vegetables by Mendelian Randomization analysis

Background

Fruits and vegetables (FVs) are widely believed to mitigate the risk of atherosclerosis (AS). However, the causal relationships between specific FVs and AS risk factors remain unclear.

Methods

This study performed two-sample Mendelian Randomization (MR) analysis to infer the causality of the intake of 28 kinds of FVs with AS, as well as its risk factors including blood low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and C-reactive protein (CRP). GWAS genetic data for these exposures and outcomes were extracted from the IEU open GWAS project. Heterogeneity was evaluated using both Inverse Variance Weighted (IVW) and MR-Egger methods. MR-Egger regression was specifically deployed to detect potential pleiotropy. Furthermore, a "leave-one-out" sensitivity analysis was conducted to determine the impact of each individual single nucleotide polymorphism (SNP) on the combined outcome.

Results

The analysis confirms a causal relationship between total fruit consumption and reduced levels of LDL-C (OR = 0.911, p = 0.007) and CRP (OR = 0.868, p = 0.008). Similarly, total vegetable intake is also causally associated with a reduction in CRP levels (OR = 0.858, p = 0.018). Specifically, garlic intake exhibits the most significant causal relationship with reduced risk of AS (OR = 0.985, p = 0.036) and also causally associated with lower levels of LDL-C and TG. Berry (OR = 0.929, p = 0.010) and potato (OR = 0.957, p = 0.020) intake both display a significant causal negative association with TG levels, while peach/nectarine consumption is significantly associated with reduced CRP levels (OR = 0.913, p = 0.010).

Conclusion

This is the first MR study that systemically examined the causality between commonly consumed FVs and AS. Our findings highlight the atheroprotective effects of various FVs, particularly garlic, on cardiovascular health and the importance of tailored nutritional recommendations to prevent AS.

Therapeutic potentials of allicin in cardiovascular disease: advances and future directions

Cardiovascular disease (CVD) remains the predominant cause of mortality and disability worldwide. Against this backdrop, finding effective drugs for the pharmacological treatment of CVD has become one of the most urgent and challenging issues in medical research. Garlic (Allium sativum L.) is one of the oldest plants and is world-renowned for its dietary and medicinal values. Allicin (diallyl thiosulfinate) is one of the primary natural active ingredients in garlic, which has been proven to have powerful cardioprotective effects and mediate various pathological processes related to CVD, such as inflammatory factor secretion, myocardial cell apoptosis, oxidative stress, and more. Therefore, allicin holds a promising application prospect in the treatment of CVD. This review summarized the biological functions of allicin and its potential mechanisms in CVD, including antioxidation, anti-inflammation, and anti-apoptosis effects. Reckoning with these, we delved into recent studies on allicin's cardioprotective effects concerning various CVDs, such as atherosclerosis, hypertension, myocardial infarction, arrhythmia, cardiac hypertrophy, heart failure, and cardiotoxicity. Further, considering the tremendous advancement in nanomedicine, nanotechnology-based drug delivery systems show promise in addressing limitations of allicin's clinical applications, including improving its solubility, stability, and bioavailability. Through this review, we hope to provide a reference for further research on allicin in cardioprotection and drug development.

Effects of Garlic on Glucose Parameters and Lipid Profile: A Systematic Review and Meta-Analysis on Randomized Controlled Trials

(1) Background: The effect of garlic on glucose and lipid metabolism in humans remains controversial. The aim of this study was to investigate the effects of garlic on blood lipid levels and glucose levels in humans through a systematic review and meta-analysis. (2) Methods: We extensively searched four databases, including PubMed, Web of Science, Embase, and the Cochrane Library, up to February 2024. To assess the collective impact of garlic and its supplements on fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), an analysis was conducted using a random effects model. Subgroup analyses were performed when I2 < 50%. (3) Result: We found that the garlic intervention was effective in controlling FBG (mean difference = -7.01; 95% CI: -8.53, -5.49, p < 0.001), HbA1c (mean deviation = -0.66; 95% CI: -0.76, -0.55, p < 0.001, I2 = 62.9%), TC (mean difference = -14.17; 95% CI: -19.31, -9.03, p < 0.001), and LDL-C (mean difference = -8.20; 95% CI: -15.58, -0.81, p = 0.03); moreover, it also increased the level of HDL-C in humans (mean difference = 2.06; 95% CI: 1.54, 2.59; p < 0.001). Nonetheless, the intervention involving garlic did not yield a substantial impact on triglyceride (TG) levels. (4) Conclusion: The intervention of garlic is beneficial to control blood glucose and blood lipids in humans.

Regulation Mechanism and Potential Value of Active Substances in Spices in Alcohol-Liver-Intestine Axis Health

Excessive alcohol intake will aggravate the health risk between the liver and intestine and affect the multi-directional information exchange of metabolites between host cells and microbial communities. Because of the side effects of clinical drugs, people tend to explore the intervention value of natural drugs on diseases. As a flavor substance, spices have been proven to have medicinal value, but they are still rare in treating hepatointestinal diseases caused by alcohol. This paper summarized the metabolic transformation of alcohol in the liver and intestine and summarized the potential value of various perfume active substances in improving liver and intestine diseases caused by alcohol. It is also found that bioactive substances in spices can exert antioxidant activity in the liver and intestine environment and reduce the oxidative stress caused by diseases. These substances can interfere with fatty acid synthesis, promote sugar and lipid metabolism, and reduce liver injury caused by steatosis. They can effectively regulate the balance of intestinal flora, promote the production of SCFAs, and restore the intestinal microenvironment.

The role of foam cells in spinal cord injury: challenges and opportunities for intervention

Spinal cord injury (SCI) results in a large amount of tissue cell debris in the lesion site, which interacts with various cytokines, including inflammatory factors, and the intrinsic glial environment of the central nervous system (CNS) to form an inhibitory microenvironment that impedes nerve regeneration. The efficient clearance of tissue debris is crucial for the resolution of the inhibitory microenvironment after SCI. Macrophages are the main cells responsible for tissue debris removal after SCI. However, the high lipid content in tissue debris and the dysregulation of lipid metabolism within macrophages lead to their transformation into foamy macrophages during the phagocytic process. This phenotypic shift is associated with a further pro-inflammatory polarization that may aggravate neurological deterioration and hamper nerve repair. In this review, we summarize the phenotype and metabolism of macrophages under inflammatory conditions, as well as the mechanisms and consequences of foam cell formation after SCI. Moreover, we discuss two strategies for foam cell modulation and several potential therapeutic targets that may enhance the treatment of SCI.

Recent advances of traditional Chinese medicine for the prevention and treatment of atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is a common systemic disease with increasing morbidity and mortality worldwide. Traditional Chinese medicine (TCM) with characteristics of multiple pathways and targets, presents advantages in the diagnosis and treatment of atherosclerosis.

AIM OF THE STUDY

With the modernization of TCM, the active ingredients and molecular mechanisms of TCM for AS treatment have been gradually revealed. Therefore, it is necessary to examine the existing studies on TCM therapies aimed at regulating AS over the past two decades.

MATERIALS AND METHODS

Using "atherosclerosis" and "Traditional Chinese medicine" as keywords, all relevant TCM literature published in the last 10 years was collected from electronic databases (such as Elsevier, Springer, PubMed, CNKI, and Web of Science), books and papers until March 2022, and the critical information was statistically analyzed.

RESULTS

In this review, we highlighted extracts of 8 single herbs, a total of 41 single active ingredients, 20 TCM formulae, and 25 patented drugs, which were described with chemical structure, source, model, efficacy and potential mechanism.

CONCLUSION

We summarized the cytopathological basis for the development of atherosclerosis involving vascular endothelial cells, macrophages and vascular smooth muscle cells, and categorically elaborated the medicinal TCM used for AS, all of which provide the current evidence on the better management of atherosclerosis by TCM.

Hydroxytyrosol Reduces Foam Cell Formation and Endothelial Inflammation Regulating the PPARγ/LXRα/ABCA1 Pathway

Cholesterol accumulation in macrophages leads to the formation of foam cells and increases the risk of developing atherosclerosis. We have verified whether hydroxytyrosol (HT), a phenolic compound with anti-inflammatory and antioxidant properties, can reduce the cholesterol build up in THP-1 macrophage-derived foam cells. We have also investigated the potential mechanisms. Oil Red O staining and high-performance liquid chromatography (HPLC) assays were utilized to detect cellular lipid accumulation and cholesterol content, respectively, in THP-1 macrophages foam cells treated with HT. The impact of HT on cholesterol metabolism-related molecules (SR-A1, CD36, LOX-1, ABCA1, ABCG1, PPARγ and LRX-α) in foam cells was assessed using real-time PCR (RT-qPCR) and Western blot analyses. Finally, the effect of HT on the adhesion of THP-1 monocytes to human vascular endothelial cells (HUVEC) was analyzed to study endothelial activation. We found that HT activates the PPARγ/LXRα pathway to upregulate ABCA1 expression, reducing cholesterol accumulation in foam cells. Moreover, HT significantly inhibited monocyte adhesion and reduced the levels of adhesion factors (ICAM-1 and VCAM-1) and pro-inflammatory factors (IL-6 and TNF-α) in LPS-induced endothelial cells. Taken together, our findings suggest that HT, with its ability to interfere with the import and export of cholesterol, could represent a new therapeutic strategy for the treatment of atherosclerotic disease.

Effects of allicin on human Simpson-Golabi-Behmel syndrome cells in mediating browning phenotype

INTRODUCTION

Obesity is a major health problem because it is associated with increased risk of cardiovascular disease, diabetes, hypertension, and some cancers. Strategies to prevent or reduce obesity focus mainly on the possible effects of natural compounds that can induce a phenotype of browning adipocytes capable of releasing energy in the form of heat. Allicin, a bioactive component of garlic with numerous pharmacological functions, is known to stimulate energy metabolism.

METHODS

In the present study, the effects of allicin on human Simpson-Golabi-Behmel Syndrome (SGBS) cells were investigated by quantifying the dynamics of lipid droplets (LDs) and mitochondria, as well as transcriptomic changes after six days of differentiation.

RESULTS

Allicin significantly promoted the reduction in the surface area and size of LDs, leading to the formation of multilocular adipocytes, which was confirmed by the upregulation of genes related to lipolysis. The increase in the number and decrease in the mean aspect ratio of mitochondria in allicin-treated cells indicate a shift in mitochondrial dynamics toward fission. The structural results are confirmed by transcriptomic analysis showing a significant arrangement of gene expression associated with beige adipocytes, in particular increased expression of T-box transcription factor 1 (TBX1), uncoupling protein 1 (UCP1), PPARG coactivator 1 alpha (PPARGC1A), peroxisome proliferator-activated receptor alpha (PPARA), and OXPHOS-related genes. The most promising targets are nuclear genes such as retinoid X receptor alpha (RXRA), retinoid X receptor gamma (RXRG), nuclear receptor subfamily 1 group H member 3 (NR1H3), nuclear receptor subfamily 1 group H member 4 (NR1H4), PPARA, and oestrogen receptor 1 (ESR1).

DISCUSSION

Transcriptomic data and the network pharmacology-based approach revealed that genes and potential targets of allicin are involved in ligand-activated transcription factor activity, intracellular receptor signalling, regulation of cold-induced thermogenesis, and positive regulation of lipid metabolism. The present study highlights the potential role of allicin in triggering browning in human SGBS cells by affecting the LD dynamics, mitochondrial morphology, and expression of brown marker genes. Understanding the potential targets through which allicin promotes this effect may reveal the underlying signalling pathways and support these findings.

Alterations of HDL's to piHDL's Proteome in Patients with Chronic Inflammatory Diseases, and HDL-Targeted Therapies

Chronic inflammatory diseases, such as rheumatoid arthritis, steatohepatitis, periodontitis, chronic kidney disease, and others are associated with an increased risk of atherosclerotic cardiovascular disease, which persists even after accounting for traditional cardiac risk factors. The common factor linking these diseases to accelerated atherosclerosis is chronic systemic low-grade inflammation triggering changes in lipoprotein structure and metabolism. HDL, an independent marker of cardiovascular risk, is a lipoprotein particle with numerous important anti-atherogenic properties. Besides the essential role in reverse cholesterol transport, HDL possesses antioxidative, anti-inflammatory, antiapoptotic, and antithrombotic properties. Inflammation and inflammation-associated pathologies can cause modifications in HDL's proteome and lipidome, transforming HDL from atheroprotective into a pro-atherosclerotic lipoprotein. Therefore, a simple increase in HDL concentration in patients with inflammatory diseases has not led to the desired anti-atherogenic outcome. In this review, the functions of individual protein components of HDL, rendering them either anti-inflammatory or pro-inflammatory are described in detail. Alterations of HDL proteome (such as replacing atheroprotective proteins by pro-inflammatory proteins, or posttranslational modifications) in patients with chronic inflammatory diseases and their impact on cardiovascular health are discussed. Finally, molecular, and clinical aspects of HDL-targeted therapies, including those used in therapeutical practice, drugs in clinical trials, and experimental drugs are comprehensively summarised.

Roles and mechanisms of garlic and its extracts on atherosclerosis: A review

The prevention and treatment of cardiovascular diseases (CVDs) have achieved initial results, but the number of CVDs patients will increase rapidly in the next 10 years. Atherosclerosis (AS) is a significant risk factor for CVDs. The impact of lifestyle and daily diet varies considerably between different countries and continents and has been shown to affect the development of various diseases such as diabetes and CVDs. Primary and secondary prevention using alternative supplements and methods to avoid or reduce the use of traditional pharmacological drugs have also become popular. One of the reasons for this is that pharmacological drugs with lipid-lowering, and blood pressure-lowering effects cause many side effects that may negatively impact the quality of life. Patients are now emphasizing reliance on lifestyle changes to reduce cardiovascular risks. Garlic is a medicinal and edible plant that has been used for a long time. In order to reveal garlic application in the prevention and treatment of AS, reviewing the latest domestic and international studies through searching databases. The result shows that the antiatherogenic role of garlic is eximious. And the mechanisms are mainly related to hypolipidemic, antioxidant, antithrombotic, inhibiting angiogenesis, protecting endothelial cells, anti-inflammatory, anti-apoptotic, inhibiting vascular smooth muscle proliferation, and regulating gut microbiota. The main signaling pathways involve AMPK/TLRs, Keap1/Nrf2, PI3K/AKT, PPARγ/LXRα, GEF-H1/RhoA/Rac, etc. The antiatherogenic actions and molecular mechanism of garlic were reviewed in this study to obtain a robust evidence basis for the clinical application and mechanistic study and provide a theoretical basis for further utilization of garlic.

D-4F, an apolipoprotein A-I mimetic, promotes the clearance of myelin debris and the reduction of foamy macrophages after spinal cord injury

After spinal cord injury (SCI), a large number of blood-derived macrophages infiltrate the lesion site and phagocytose myelin debris to become foamy macrophages, which leads to chronic inflammation. The drug D-4F, an apolipoprotein A-I peptidomimetic made of D-amino acids, has been reported to promote the lipid metabolism of foamy macrophages in atherosclerosis. However, the role and mechanism of D-4F in SCI are still unclear. In this study, we found that D-4F can promote the removal of myelin debris, reduce the formation of foamy macrophages in the lesion core and promote neuroprotection and recovery of motor function after SCI. These beneficial functions of D-4F may be related to its ability to upregulate the expression of ATP-binding cassette transporter A1 (ABCA1), the main transporter that mediates lipid efflux in foamy macrophages because inhibiting the activity of ABCA1 can reverse the effect of D-4F in vitro. In conclusion, D-4F may be a promising candidate for treating SCI by promoting the clearance of myelin debris by foamy macrophages via the ABCA1 pathway.

Attenuating oxidized low density lipoprotein (ox-LDL)-induced macrophages damage via inhibiting C-type lectin domain family 2 (CLEC2) expression through janus kinase 1 (JAK1)/ signal transducers and activators of transcription-1 (STAT1) pathway

Our study aimed to explore the effect of C-type lectin-like receptor 2 (CLEC2) expression level on oxidized low-density lipoprotein (ox-LDL)-induced macrophage damage and the regulatory mechanism of macrophage foaming. Foam cells were derived from RAW264.7 by ox-LDL, and the cell viability was detected by cell counting kit-8 (CCK-8) assay. Enzyme-linked immunosorbent assay (ELISA) was applied to detect the levels of inflammatory cytokines tumor necrosis factor (TNF-α), Interleukin-6 (IL-6), and Interleulin-1β (IL-1β). Small interfering CLEC2 (si-CLEC2) was synthesized and transfected into RAW264.7, and the apoptosis rate was analyzed by flow cytometry. Western blotting was employed to detect the protein expressions of Janus kinase 1 (JAK1), Signal transducers and activators of transcription-1 (STAT1), phosphorylation-JAK1 (p-JAK1), phosphorylation-STAT1 (p-STAT1), CLEC2, and the apoptosis-related proteins. The levels of total cholesterol (TC) and free cholesterol (FC) were measured using colorimetric kits. Results showed that ox-LDL could activate the JAK1/STAT1 pathway of macrophages and up-regulate the expression of CLEC2. CLEC2 knockdown could reduce macrophage inflammation and lipid accumulation. Inactivating JAK1/STAT1 pathway with JAK1 inhibitor can significantly reduce the phosphorylation of STAT1 and alleviate the ox-LDL-induced damage in macrophages by regulating the expression of CLEC2. In conclusion, targeting JAK1/STAT1 to inhibit CLEC2 can attenuate ox-LDL-induced macrophage damage. This study enriched the pathogenesis of atherosclerosis and provided the possible treatment targets.

PPARγ Ameliorates Mycobacterium tuberculosis H37Ra-Induced Foamy Macrophage Formation via the ABCG1-Dependent Cholesterol Efflux Pathway in THP-1 Macrophages

Foamy macrophages are present during the course of Mycobacterium tuberculosis (Mtb) infection and seems to be nutrient-rich reservoir and secure reservoir for the bacilli, which leads to bacterial persistence and infection transmission. Peroxisome proliferator activated receptor γ (PPARγ) is a key transcription factor for cholesterol metabolism in macrophages and its role in regulating atherosclerosis related foamy macrophages (FMs) formation has been well-studied. However, knowledge about the mechanism of PPARγ regulating Mtb infection induced FM formation remains very limited. In this study, we investigate the functional role of PPARγ in Mtb H37Ra infection-induced foamy macrophages formation. H37Ra infection induced a time-dependent decreased expression of PPARγ that paralleled the augmented lipid body formation in THP1-derived macrophages. PPARγ antagonist GW9662 significantly potentiate H37Ra induced lipid body formation and inhibit ABCG1 expression, overexpression of ABCG1 by transduced macrophages with lentivirus significantly reversed the promotion effect of GW9662 on FM formation. Moreover, Treatment with a TLR2 neutralizing antibody ameliorated the activation of ABCG1 by Mtb H37Ra without significantly effecting the suppression of PPARγ, suggesting a greater role for TLR2 to regulate ABCG1 compared to PPARγ. Overall, this study showed that PPARγ is involved in ameliorating FM formation by regulating ABCG1 expression, these observations expose a novel role of PPARγ in the Mtb infection induced FM formation.

Cholesterol-Lowering Phytochemicals: Targeting the Mevalonate Pathway for Anticancer Interventions

There are a plethora of cancer causes and the road to fully understanding the carcinogenesis process remains a dream that keeps changing. However, a list of role players that are implicated in the carcinogens process is getting lengthier. Cholesterol is known as bad sterol that is heavily linked with cardiovascular diseases; however, it is also comprehensively associated with carcinogenesis. There is an extensive list of strategies that have been used to lower cholesterol; nevertheless, the need to find better and effective strategies remains vastly important. The role played by cholesterol in the induction of the carcinogenesis process has attracted huge interest in recent years. Phytochemicals can be dubbed as magic tramp cards that humans could exploit for lowering cancer-causing cholesterol. Additionally, the mechanisms that are regulated by phytochemicals can be targeted for anticancer drug development. One of the key role players in cancer development and suppression, Tumour Protein 53 (TP53), is crucial in regulating the biogenesis of cholesterol and is targeted by several phytochemicals. This minireview covers the role of p53 in the mevalonate pathway and how bioactive phytochemicals target the mevalonate pathway and promote p53-dependent anticancer activities.

Macrophage polarization by potential nutraceutical compounds: A strategic approach to counteract inflammation in atherosclerosis

Chronic inflammation represents a main event in the onset and progression of atherosclerosis and is closely associated with oxidative stress in a sort of vicious circle that amplifies and sustains all stages of the disease. Key players of atherosclerosis are monocytes/macrophages. According to their pro- or anti-inflammatory phenotype and biological functions, lesional macrophages can release various mediators and enzymes, which in turn contribute to plaque progression and destabilization or, alternatively, lead to its resolution. Among the factors connected to atherosclerotic disease, lipid species carried by low density lipoproteins and pro-oxidant stimuli strongly promote inflammatory events in the vasculature, also by modulating the macrophage phenotyping. Therapies specifically aimed to balance macrophage inflammatory state are increasingly considered as powerful tools to counteract plaque formation and destabilization. In this connection, several molecules of natural origin have been recognized to be active mediators of diverse metabolic and signaling pathways regulating lipid homeostasis, redox state, and inflammation; they are, thus, considered as promising candidates to modulate macrophage responsiveness to pro-atherogenic stimuli. The current knowledge of the capability of nutraceuticals to target macrophage polarization and to counteract atherosclerotic lesion progression, based mainly on in vitro investigation, is summarized in the present review.

Knockdown of mesenchymal stem cell‑derived exosomal LOC100129516 suppresses the symptoms of atherosclerosis via upregulation of the PPARγ/LXRα/ABCA1 signaling pathway

Mesenchymal stem cell (MSC) therapy has potential applications in treating atherosclerosis and coronary heart disease (CAD). Previous studies have demonstrated that MSCs are the most preferable sources of therapeutic exosomes, which carry long non‑coding RNAs and participate in the progression of atherosclerosis. The results of our previous bioinformatics study demonstrated that the levels of LOC100129516 were significantly upregulated in peripheral blood mononuclear cells obtained from patients with CAD. However, the biological role of LOC100129516 in the development of atherosclerosis remains to be elucidated. In the present study, THP‑1 cells were treated with oxidized low‑density lipoproteins to induce foam cell formation in vitro. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to detect the levels of LOC100129516 in THP‑1 macrophage‑derived foam cells. In addition, an in vivo model of atherosclerosis was established using Apolipoprotein E (ApoE) knockout (ApoE‑/‑) mice. The results of the RT‑qPCR assays demonstrated that the levels of LOC100129516 were upregulated in THP‑1 macrophage‑derived foam cells. MSC‑derived exosomes were able to deliver small interfering (si)‑LOC100129516 to THP‑1 cells to reduce the levels of LOC100129516. Moreover, transfection of si‑LOC100129516 via exosomal delivery significantly decreased the levels of total cholesterol (TC), free cholesterol and cholesterol ester in THP‑1 macrophage‑derived foam cells. Exosomal‑mediated delivery of si‑LOC100129516 decreased TC levels and low‑density lipoprotein levels in the ApoE‑/‑ atherosclerosis mouse model. Mechanistically, exosomal‑mediated delivery of si‑LOC100129516 promoted cholesterol efflux by activating the peroxisome proliferator‑activated receptor γ (PPARγ)/liver X receptor α (LXRα)/phospholipid‑transporting ATPase ABCA1 (ABCA1) signaling pathway in vitro and in vivo. Collectively, these results suggested that exosomal‑mediated delivery of si‑LOC100129516, in which the exosomes were derived from MSCs, promoted cholesterol efflux and suppressed intracellular lipid accumulation, ultimately alleviating the progression of atherosclerosis via stimulation of the PPARγ/LXRα/ABCA1 signaling pathway.

Increased protein expression of ABCA1, HMG-CoA reductase, and CYP46A1 induced by garlic and allicin in the brain mouse and astrocytes-isolated from C57BL/6J

Objective:

Regulation of cholesterol level is essential for the brain optimal function. The beneficial effect of garlic consumption on cholesterol homeostasis is well known; however, the molecular mechanism to support its properties is unclear. Here, we investigated the beneficial effect of aqueous extract of garlic and allicin on lipid profile and the main players involved in brain cholesterol homeostasis including ABCA1, HMG-CoA reductase, and CYP46A1 in both C57BL/6J mice brain and astrocytes.

Materials and Methods:

Thirty mice were divided into control and garlic groups. Garlic group was fed with the aqueous extract of garlic. Serum lipids were measured and brain protein levels of ABCA1, HMGCR, and CYP46A1 were determined by western blotting. Changes in these proteins expression were also studied in the presence of allicin in cultured astrocytes.

Results:

A moderate decrease in serum total cholesterol and a significant increase in plasma HDL-C levels (p<0.05) were detected. A significant increase in ABCA1, HMGCR, and CYP46A1 protein levels was observed in the garlic group and in the cultured astrocytes treated with allicin by western blotting (p<0.05).

Conclusion:

Our findings indicated that the main players involved in cholesterol turnover including HMGCR that is involved in cholesterol synthesis, ABCA1 that is important in cholesterol efflux, and CYP46A1 that is necessary in cholesterol degradation, were up regulated by garlic/allicin in both animal and cell culture model. We concluded that increasing cholesterol turnover is a possible mechanism for the beneficial effects of garlic in cholesterol homeostasis.

Allium-Derived Compound Propyl Propane Thiosulfonate (PTSO) Attenuates Metabolic Alterations in Mice Fed a High-Fat Diet through Its Anti-Inflammatory and Prebiotic Properties

Background: Propyl propane thiosulfonate (PTSO) is an organosulfur compound from Allium spp. that has shown interesting antimicrobial properties and immunomodulatory effects in different experimental models. In this sense, our aim was to evaluate its effect on an experimental model of obesity, focusing on inflammatory and metabolic markers and the gut microbiota. Methods and results: Mice were fed a high-fat diet and orally treated with different doses of PTSO (0.1, 0.5 and 1 mg/kg/day) for 5 weeks. PTSO lessened the weight gain and improved the plasma markers associated with glucose and lipid metabolisms. PTSO also attenuated obesity-associated systemic inflammation, reducing the immune cell infiltration and, thus, the expression of pro-inflammatory cytokines in adipose and hepatic tissues (Il-1ẞ, Il-6, Tnf-α, Mcp-1, Jnk-1, Jnk-2, Leptin, Leptin R, Adiponectin, Ampk, Ppar-α, Ppar-γ, Glut-4 and Tlr-4) and improving the expression of different key elements for gut barrier integrity (Muc-2, Muc-3, Occludin, Zo-1 and Tff-3). Additionally, these effects were connected to a regulation of the gut microbiome, which was altered by the high-fat diet. Conclusion: Allium-derived PTSO can be considered a potential new tool for the treatment of metabolic syndrome.

Macrophage phagocytosis after spinal cord injury: when friends become foes

After spinal cord injury (SCI), macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in SCI, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of SCI.

Effects of Danhong injection on dyslipidemia and cholesterol metabolism in high-fat diets fed rats

ETHNOPHARMACOLOGICAL RELEVANCE

Danhong injection (DHI) is a Chinese medical injection applied to the clinical treatment of cardiovascular diseases that has anti-inflammatory, antiplatelet aggregation and antithrombotic effects. This study aimed to explore the effects of DHI on dyslipidemia and cholesterol metabolism in high-fat diet-fed rats.

METHODS

Sprague Dawley (SD) rats were randomly divided into six groups: normal group (Normal); hyperlipidemia model group (Model); DHI-treated groups at doses of 1.0 mL/kg, 2.0 mL/kg, 4.0 mL/kg; and simvastatin positive control group (2.0 mg/kg). The hypolipidemic effects of DHI were evaluated by measuring serum lipid levels, hepatic function and oxidative stress, respectively. And pathological changes in liver tissues were determined using hematoxylin-eosin (H&E) and oil red O staining. Moreover, the mRNA and protein expression levels of cholesterol metabolism related genes were detected by real-time PCR (RT-PCR) and Western blot.

RESULTS

Compared with the Model group, DHI treatment markedly decreased the liver index and improved the pathological morphology of liver tissues. DHI treatment dose-dependently decreased the levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), malondialdehyde (MDA), and free fatty acids (FFA) in serum or liver tissues (P < 0.01 or P < 0.05), and increased the high-density lipoprotein cholesterol (HDL-C) and tripeptide glutathione (GSH) (P < 0.01 or P < 0.05). The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were increased in the DHI-treated groups (P < 0.01 or P < 0.05), while the alanine transaminase (ALT) and aspartate transaminase (AST) were decreased (P < 0.01 or P < 0.05). Furthermore, the expression levels of LDL receptor (LDLR), cholesterol 7-α-hydroxylase (CYP7A1), liver X receptor α (LXRα), and peroxisome proliferator-activated receptor α (PPARα) were dose-dependently upregulated in the DHI-treated groups, whereas the expression of sterol regulatory element-binding protein-2 (SREBP-2) was downregulated.

CONCLUSIONS

Our study demonstrated that DHI markedly ameliorated hyperlipidemia rats by regulating serum lipid levels, inhibiting hepatic lipid accumulation and steatosis, improving hepatic dysfunction, and reducing oxidative stress. The potential mechanism was also tentatively investigated and may be related to the promotion of bile acid synthesis via activation of the PPARα-LXRα-CYP7A1 pathway. Therefore, DHI could be regarded as a potential hypolipidemic drug for the treatment of hyperlipidemia.

Recent Molecular Mechanisms and Beneficial Effects of Phytochemicals and Plant-Based Whole Foods in Reducing LDL-C and Preventing Cardiovascular Disease

Abnormal lipid metabolism leads to the development of hyperlipidemia, a common cause of multiple chronic disorders, including cardiovascular disease (CVD), obesity, diabetes, and cerebrovascular disease. Low-density lipoprotein cholesterol (LDL-C) currently remains the primary target for treatment of hyperlipidemia. Despite the advancement of treatment and prevention of hyperlipidemia, medications used to manage hyperlipidemia are limited to allopathic drugs, which present certain limitations and adverse effects. Increasing evidence indicates that utilization of phytochemicals and plant-based whole foods is an alternative and promising strategy to prevent hyperlipidemia and CVD. The current review focuses on phytochemicals and their pharmacological mode of actions for the regulation of LDL-C and prevention of CVD. The important molecular mechanisms illustrated in detail in this review include elevation of reverse cholesterol transport, inhibition of intestinal cholesterol absorption, acceleration of cholesterol excretion in the liver, and reduction of cholesterol synthesis. Moreover, the beneficial effects of plant-based whole foods, such as fresh fruits, vegetables, dried nuts, flax seeds, whole grains, peas, beans, vegan diets, and dietary fibers in LDL-C reduction and cardiovascular health are summarized. This review concludes that phytochemicals and plant-based whole foods can reduce LDL-C levels and lower the risk for CVD.

Septin 4 activates PPARγ/LXRα signaling by upregulating ABCA1 and ABCG1 expression to inhibit the formation of THP-1 macrophage-derived foam cells

Septin 4 is a member of a family of GTP-binding proteins that has been previously reported regulate cytoskeletal organization. In addition, it has been suggested to serve a role in atherosclerosis. Therefore, the present study aimed to investigate the effects of Septin 4 on foam cell formation. THP-1 cells were first exposed to phorbol-12-myristate-13-acetate for differentiation into macrophages before being transformed into foam cells by treatment with oxidized low-density lipoprotein (ox-LDL). Septin 4 expression was then knocked down or overexpressed in THP-1 cells using transfection, whilst peroxisome proliferator activated receptor γ (PPARγ) was also inhibited using its selective antagonist (T0070907) in the presence of Septin 4 overexpression. Oil red staining was used to detect lipid uptake, and total cholesterol (TC), free cholesterol (FC) and ATP binding cassette subfamily A/G member 1 (ABCA1/G1) protein expression were also measured. The results demonstrated that upon ox-LDL stimulation, macrophages that were derived from THP-1 cells transformed into foam cells, where Septin 4 was highly expressed in ox-LDL-induced foam cells. Septin 4 knockdown promoted TC and FC levels, but reduced ABCA1/G1 protein expression. The protein expression levels of PPARγ and liver X receptor α (LXRα) were also decreased after Septin 4 knockdown. However, Septin 4 overexpression resulted in the opposite results being observed. Additionally, blocking PPARγ activity using its inhibitor T0070907 or knocking down LXRα expression using short hairpin RNA reversed the effects of Septin 4 overexpression on foam cell formation and cholesterol handling. In conclusion, Septin 4 may serve an important role in preventing foam cell formation by activating PPARγ/LXRα signaling and subsequently enhancing ABCA1/G1 expression.

Light-To-Moderate Raw Garlic Consumption Frequency Is Inversely Associated With Thickened Carotid Intima-Media Thickness: A Population-Based Study

Background: Previous animal and clinical studies have reported beneficial effects of garlic preparations on carotid intima-media thickness (cIMT). However, no epidemiological study has yet investigated the association between dietary raw garlic consumption and cIMT in the general population. The objective of this study was investigating the association between dietary raw garlic consumption and thickened cIMT in Chinese adults. Methods: This cross-sectional study used data from the Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study. A total of 4,329 general adults from 2015 to 2017 were included in this study. Frequency of consumption of raw garlic was summarized as four categories for analysis: < 1 time/week, 1 time/week, 2-3 times/week, ≥4 times/week with a validated food frequency questionnaire. The thickened cIMT was defined as common carotid artery IMT ≥ 1.0 mm or a carotid bifurcation IMT ≥ 1.2 mm by ultrasonography. Multivariable logistic regression analysis was used to examine the association between frequency of raw garlic consumption and thickened cIMT. Results: The prevalence of thickened cIMT is 22.9% among these participants. The adjusted odds ratios (95% confidence intervals) associated with the different frequencies were 1.00 (reference) for < 1 time/week, 0.74 (0.59, 0.94) for 1 time/week, 0.71 (0.55, 0.92) for 2-3 times/week, and 0.94 (0.71, 1.25) for ≥ 4 times/week. Conclusions: Light-to-moderate raw garlic consumption was inversely associated with thickened cIMT, whereas greater raw garlic consumption (i.e., ≥4 times/week) was not associated with thickened cIMT. Future longitudinal studies should be conducted to test these findings.

Filifactor alocis and Tumor Necrosis Factor-Alpha Stimulate Synthesis of Visfatin by Human Macrophages

There is little known about the effect of the periodontopathogen Filifactor alocis on macrophages as key cells of the innate immune defense in the periodontium. Therefore, the aim of the present study was to investigate the effect of F. alocis and additionally of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) on visfatin and other pro-inflammatory and proteolytic molecules associated with periodontitis in human macrophages. The presence of macrophage markers CD14, CD86, CD68, and CD163 was examined in gingival biopsies from healthy individuals and periodontitis patients. Human macrophages were incubated with F. alocis and TNFα for up to 2 d. The effects of both stimulants on macrophages were determined by real-time PCR, ELISA, immunocytochemistry, and immunofluorescence. F. alocis was able to significantly stimulate the synthesis of visfatin by human macrophages using TLR2 and MAPK pathways. In addition to visfatin, F. alocis was also able to increase the synthesis of cyclooxygenase 2, TNFα, and matrix metalloproteinase 1. Like F. alocis, TNFα was also able to stimulate the production of these proinflammatory and proteolytic molecules. Our results highlight the pathogenetic role of F. alocis in periodontal diseases and also underline the involvement of visfatin in the aetiopathogenesis of periodontitis.

Effects of phytochemicals on macrophage cholesterol efflux capacity: Impact on atherosclerosis

High-density lipoprotein cholesterol (HDL) is the major promoter of reverse cholesterol transport and efflux of excess cellular cholesterol. The functions of HDL, such as cholesterol efflux, are associated with cardiovascular disease rather than HDL levels. We have reviewed the evidence base on the major classes of phytochemicals, including polyphenols, alkaloids, carotenoids, phytosterols, and fatty acids, and their effects on macrophage cholesterol efflux and its major pathways. Phytochemicals show the potential to improve the efficiency of each of these pathways. The findings are mainly in preclinical studies, and more clinical research is warranted in this area to develop novel clinical applications.

Current state and future perspective of cardiovascular medicines derived from natural products

The contribution of natural products (NPs) to cardiovascular medicine has been extensively documented, and many have been used for centuries. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Over the past 40 years, approximately 50% of newly developed cardiovascular drugs were based on NPs, suggesting that NPs provide essential skeletal structures for the discovery of novel medicines. After a period of lower productivity since the 1990s, NPs have recently regained scientific and commercial attention, leveraging the wealth of knowledge provided by multi-omics, combinatorial biosynthesis, synthetic biology, integrative pharmacology, analytical and computational technologies. In addition, as a crucial part of complementary and alternative medicine, Traditional Chinese Medicine has increasingly drawn attention as an important source of NPs for cardiovascular drug discovery. Given their structural diversity and biological activity NPs are one of the most valuable sources of drugs and drug leads. In this review, we briefly described the characteristics and classification of NPs in CVDs. Then, we provide an up to date summary on the therapeutic potential and the underlying mechanisms of action of NPs in CVDs, and the current view and future prospect of developing safer and more effective cardiovascular drugs based on NPs.

Tithonia diversifolia-derived orizabin suppresses cell adhesion, differentiation, and oxidized LDL accumulation by Akt signaling suppression via PTEN promotion in THP-1 cells

As a Japanese folk medicine, Tithonia diversifolia is used for cardiovascular disease prevention and health maintenance. We isolated T. diversifolia-derived orizabin based on the nitric oxide production inhibitory effect. This study aimed to consider orizabin as a novel functional compound with anti-atherosclerotic activity. Orizabin significantly inhibited the adhesion of THP-1 cells to human umbilical vein endothelial cells (HUVECs) and suppressed the mRNA expression of adhesion molecules in HUVECs. In Phorbol 12-myristate 13-acetate stimulated THP-1 cells, orizabin suppressed macrophage differentiation, CD36 expression (1% at 10 μM), and NFκB transcriptional activity. Furthermore, orizabin suppressed oxidized low-density lipoprotein (oxLDL) uptake in macrophages and the Akt phosphorylation. On the contrary, we revealed that phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN) mRNA and protein expression were promoted significantly by orizabin (mRNA, 270-fold at 10 μM). Our study presented the possibility that T. diversifolia-derived orizabin is novel anti-atherosclerotic compound via the suppression of Akt phosphorylation, and T. diversifolia may be effective as a new crop for vascular health maintenance. PRACTICAL APPLICATIONS: In this study, the differentiation of monocytes was suppressed without any toxicity, it was obvious in the image, and the oxLDL uptake in monocytes was clearly suppressed by orizabin. Our findings presented that T. diversifolia-derived compound orizabin specifically contributes to the promotion of PTEN expression and suppression of Akt signal in cells, and acts to suppress inflammation by suppression of NFκB transcriptional activity. As a component derived from food, it has a strong function and can be used to maintain the health for blood vessels. It is also a finding that deserves to expand production currently being carried out on a small scale. Furthermore, the promoting effect of PTEN known as a cancer suppressor in orizabin may result in further use for pharmaceuticals research. Orizabin can be safely used as a food-derived compound for maintaining human health.

FGF21 induces autophagy-mediated cholesterol efflux to inhibit atherogenesis via RACK1 up-regulation

Fibroblast growth factor 21 (FGF21) acts as an anti‐atherosclerotic agent. However, the specific mechanisms governing this regulatory activity are unclear. Autophagy is a highly conserved cell stress response which regulates atherosclerosis (AS) by reducing lipid droplet degradation in foam cells. We sought to assess whether FGF21 could inhibit AS by regulating cholesterol metabolism in foam cells via autophagy and to elucidate the underlying molecular mechanisms. In this study, ApoE^−/− mice were fed a high‐fat diet (HFD) with or without FGF21 and FGF21 + 3‐Methyladenine (3MA) for 12 weeks. Our results showed that FGF21 inhibited AS in HFD‐fed ApoE^−/− mice, which was reversed by 3MA treatment. Moreover, FGF21 increased plaque RACK1 and autophagy‐related protein (LC3 and beclin‐1) expression in ApoE^−/− mice, thus preventing AS. However, these proteins were inhibited by LV‐RACK1 shRNA injection. Foam cell development is a crucial determinant of AS, and cholesterol efflux from foam cells represents an important defensive measure of AS. In this study, foam cells were treated with FGF21 for 24 hours after a pre‐treatment with 3MA, ATG5 siRNA or RACK1 siRNA. Our results indicated that FGF21‐induced autophagy promoted cholesterol efflux to reduce cholesterol accumulation in foam cells by up‐regulating RACK1 expression. Interestingly, immunoprecipitation results showed that RACK1 was able to activate AMPK and interact with ATG5. Taken together, our results indicated that FGF21 induces autophagy to promote cholesterol efflux and reduce cholesterol accumulation in foam cells through RACK1‐mediated AMPK activation and ATG5 interaction. These results provided new insights into the molecular mechanisms of FGF21 in the treatment of AS.

Recombinant Klotho protein enhances cholesterol efflux of THP-1 macrophage-derived foam cells via suppressing Wnt/β-catenin signaling pathway

BACKGROUND

Atherosclerosis (AS) is the basis of cardiovascular diseases, characterized by chronic inflammatory and lipid metabolism disorders. Although the anti-inflammatory effect of Klotho in AS has been clearly shown, its lipid-lowering effect is unclear. In this study, we examined the effects of recombinant Klotho (Re-KL) protein on lipid accumulation in foam cells.

METHODS

THP-1 cells were exposed to 100 nM phorbol myristate acetate for 24 h and then to oxidized low-density lipoprotein (ox-LDL; 80 mg/mL) to induce foam cell formation. Subsequently, the foam cells were incubated with Re-KL and/or DKK1, an inhibitor of the Wnt/β-catenin pathway.

RESULTS

Oil red O staining and cholesterol intake assay revealed that the foam cell model was constructed successfully. Pre-treatment of the foam cells with Re-KL decreased total cholesterol level, up-regulated the expression of ATP binding cassette transporter A1 (ABCA1) and G1 (ABCG1), and down-regulated the expression of acyl coenzyme a-cholesterol acyltransferase 1 (ACAT1) and members of the scavenger family (SR-A1 and CD36). In addition, the expression of Wnt/β-catenin pathway-related proteins in foam cells was significantly decreased by the stimulus of Re-KL. Interestingly, the effect of Re-KL was similar to that of DKK1 on foam cells.

CONCLUSIONS

The Re-KL-induced up-regulation of reverse cholesterol transport capacity promotes cholesterol efflux and reduces lipid accumulation by suppressing the Wnt/β-catenin pathway in foam cells.

Allicin pharmacology: Common molecular mechanisms against neuroinflammation and cardiovascular diseases

According to investigations in phytomedicine and ethnopharmacology, the therapeutic properties of garlic (Allium sativum) have been described by ancestral cultures. Notwithstanding, it is of particular concern to elucidate the molecular mechanisms underlying this millenary empirical knowledge. Allicin (S-allyl prop-2-ene-1-sulfinothioate), a thioester of sulfenic acid, is one of the main bioactive compounds present in garlic, and it is responsible for the particular aroma of the spice. The pharmacological attributes of allicin integrate a broad spectrum of properties (e.g., anti-inflammatory, immunomodulatory, antibiotic, antifungal, antiparasitic, antioxidant, nephroprotective, neuroprotective, cardioprotective, and anti-tumoral activities, among others). The primary goal of the present article is to review and clarify the common molecular mechanisms by which allicin and its derivates molecules may perform its therapeutic effects on cardiovascular diseases and neuroinflammatory processes. The intricate interface connecting the cardiovascular and nervous systems suggests that the impairment of one organ could contribute to the dysfunction of the other. Allicin might target the cornerstone of the pathological processes underlying cardiovascular and neuroinflammatory disorders, like inflammation, renin-angiotensin-aldosterone system (RAAS) hyperactivation, oxidative stress, and mitochondrial dysfunction. Indeed, the current evidence suggests that allicin improves mitochondrial function by enhancing the expression of HSP70 and NRF2, decreasing RAAS activation, and promoting mitochondrial fusion processes. Finally, allicin represents an attractive therapeutic alternative targeting the complex interaction between cardiovascular and neuroinflammatory disorders.

Impact of natural products on the cholesterol transporter ABCA1

ETHNOPHARMACOLOGICAL RELEVANCE

In different countries and areas of the world, traditional medicine has been and is still used for the treatment of various disorders, including chest pain or liver complaints, of which we now know that they can be linked with altered lipid and cholesterol homeostasis. As ATP-binding cassette transporter A1 (ABCA1) plays an essential role in cholesterol metabolism, its modulation may be one of the molecular mechanisms responsible for the experienced benefit of traditional recipes. Intense research activity has been dedicated to the identification of natural products from traditional medicine that regulate ABCA1 expression.

AIMS OF THE REVIEW

This review surveys natural products, originating from ethnopharmacologically used plants, fungi or marine sources, which influence ABCA1 expression, providing a reference for future study.

MATERIALS AND METHODS

Information on regulation of ABCA1 expression by natural compounds from traditional medicine was extracted from ancient and modern books, materia medica, and electronic databases (PubMed, Google Scholar, Science Direct, and ResearchGate).

RESULTS

More than 60 natural compounds from traditional medicine, especially traditional Chinese medicine (TCM), are reported to regulate ABCA1 expression in different in vitro and in vivo models (such as cholesterol efflux and atherosclerotic animal models). These active compounds belong to the classes of polyketides, terpenoids, phenylpropanoids, tannins, alkaloids, steroids, amino acids and others. Several compounds appear very promising in vivo, which need to be further investigated in animal models of diseases related to ABCA1 or in clinical studies.

CONCLUSION

Natural products from traditional medicine constitute a large promising pool for compounds that regulate ABCA1 expression, and thus may prevent/treat diseases related to cholesterol metabolism, like atherosclerosis or Alzheimer's disease. In many cases, the molecular mechanisms of these natural products remain to be investigated.

Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products

Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.

Novel lipid-modifying therapies addressing unmet needs in cardiovascular disease

Cardiovascular disease (CVD) remains a major cause of morbidity and mortality worldwide. Currently, it is well established that dyslipidemia is one of the major risk factors leading to the development of atherosclerosis and CVD. Statins remain the standard-of-care in the treatment of hypercholesterolemia and their use has significantly reduced cardiovascular morbidity and mortality. In addition, recent advances in lipid-modifying therapies, such as the development of proprotein convertase subtilisin/kexin type 9 inhibitors, have further improved cardiovascular outcomes in patients with hypercholesterolemia. However, despite significant progress in the treatment of dyslipidemia, there is still considerable residual risk of recurring cardiovascular events. Furthermore, in some cases, an effective therapy for the identified primary cause of a specific dyslipidemia has not been found up to date. Thus, a number of novel pharmacological interventions are under early human trials, targeting different molecular pathways of lipid formation, regulation and metabolism. This editorial aims to discuss the current clinical and scientific data on new promising lipid-modifying therapies addressing unmet needs in CVD, which may prove beneficial in the near future.

Polychlorinated Biphenyl Quinone Promotes Macrophage-Derived Foam Cell Formation

Polychlorinated biphenyls (PCBs) are organic environmental pollutants that are accused of various toxic effects. PCB exposure is widely believed to be associated with atherosclerosis, but the underlying mechanisms are unclear. Although PCBs are easily metabolized, there is rarely information on the effects of their metabolites on atherosclerosis. Currently, we evaluate the effect of 2,3,5-trichloro-6-phenyl-[1,4]-benzoquinone (PCB29-pQ) on the critical phase of atherosclerosis development, that is, the formation of macrophage-derived foam cells. We exposed Ox-LDL-induced RAW264.7 cells to 2.5 μM and 5 μM PCB29-pQ. Varieties of evidence have demonstrated that PCB29-pQ promotes foam cell formation and develops proinflammatory cascade and cell necroptosis. In detail, we observed that PCB29-pQ increased levels of total cholesterol (TC), free cholesterol (FC), triglyceride (TG), and cholesteryl ester (CE) by increasing the cholesterol influx and reducing the cholesterol efflux. Moreover, we found that PCB29-pQ induced inflammatory cytokines, such as tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and IL-1β, released by activating the mitogen-activated protein kinase (MAPK)-nuclear factor kappa B (NF-κB) inflammatory pathway. In addition, we demonstrated that PCB29-pQ induced cell necroptosis via receptor interacting protein kinases 1 and 3 (RIPK1/3) and a mixed-lineage kinase domain-like (MLKL) pathway. Finally, the overproduction of reactive oxygen species (ROS) by PCB29-pQ played significant roles in these processes, which could be reversed with an antioxidant. Overall, our results indicated that PCB29-pQ promoted the macrophage formation of foam cells, inflammation, and cell necroptosis.

Allicin Inhibited Staphylococcus aureus -Induced Mastitis by Reducing Lipid Raft Stability via LxRα in Mice

Mastitis, inflammation of the mammary gland, occurs in both humans and animals. Staphylococcus aureus is the most common infectious bacterial pathogen associated with mastitis. We investigated the effects of allicin on S. aureus-induced mastitis in mice. Pathological histology revealed that allicin inhibited S. aureus-induced pathological damage and myeloperoxidase activity in mammary tissues. Enzyme-linked immunosorbent assays demonstrated that allicin reduced the production of IL-1β and TNF-α as well as inhibited the NF-κB and mitogen-activated protein kinase pathway by reducing phosphorylation of p65, IκBα, p38, JNK, and ERK. Western blotting revealed that allicin reduced TLR2 and TLR6 expression in mammary tissues and cells but not in HEK293 cells. The lipid raft content was reduced by allicin, which inhibited signaling downstream of TLR2 and TLR6. Liver X receptor α (LXRα) luciferase reporter assays and LXRα interference experiments showed that allicin improved the LXRα activity and adenosine 5'-triphosphate-binding cassette G and A1 (ABCG and ABCA1) expression, thereby reducing the cholesterol level, lipid raft formation, and downstream TLR2 and TLR6 pathway activity. These results demonstrated that allicin exerted anti-inflammatory effects against S. aureus mastitis by improving the LXRα activity and reducing lipid raft formation.

Inheritance of high and low HDL: mechanisms and management

PURPOSE OF REVIEW

The inverse association between plasma high-density lipoprotein cholesterol (HDL-C) concentration and the incidence of cardiovascular disease (CVD) has been unequivocally proven by many epidemiological studies. There are several genetic disorders affecting HDL-C plasma levels, either providing atheroprotection or predisposing to premature atherosclerosis. However, up to date, there has not been any pharmacological intervention modulating HDL-C levels, which has been clearly shown to prevent the progression of CVD. Thus, clarifying the exact underlying mechanisms of inheritance of these genetic disorders that affect HDL is a current goal of the research, as key roles of molecular components of HDL metabolism and function can be revealed and become targets for the discovery of novel medications for the prevention and treatment of CVD.

RECENT FINDINGS

Primary genetic disorders of HDL can be either associated with longevity or, in contrast, may lead to premature CVD, causing high morbidity and mortality to their carriers. A large body of recent research has closely examined the genetic disorders of HDL and new promising therapeutic strategies have been developed, which may be proven beneficial in patients predisposed to CVD in the near future.

SUMMARY

We have reviewed recent findings on the inheritance of genetic disorders associated with high and low HDL-C plasma levels and we have discussed their clinical features, as well as information about new promising HDL-C-targeted therapies that are under clinical trials.

Chronic Unpredictable Mild Stress Promotes Atherosclerosis via HMGB1/TLR4-Mediated Downregulation of PPARγ/LXRα/ABCA1 in ApoE-/- Mice

Background: Although our previous studies have confirmed that the activation of TLR4 is implicated in the development of atherosclerosis induced by chronic unpredicted mild stress (CUMS), the underling mechanism is largely unclear. Here, we hypothesized that CUMS accelerates atherosclerotic development through lowering PPARγ/LXRα-ABCA1 expression via HMGB1/TLR4 signaling. Methods: In present study, CUMS atherosclerotic animal models were established with AopE^-/- mice, and CUMS Raw 264.7 macrophage models were mimicked by high corticosterone treatment, These models were treated with Ethyl pyruvate (EP, an inhibitor of HMGB1), TLR4 inhibitor TAK-242, and PPARγ agonist RSG (Rosiglitazone) to test our hypothesis, respectively. Results: Our results indicated that the protein levels of HMGB1, TLR4, and pro-inflammatory cytokines including IL-1β, TNF-α were elevated with the development of atherosclerosis in CUMS mice, while the expressions of PPARγ, LXRα, and ABCA1 declined. Notably, HMGB1 inhibition by EP reversed CUMS-induced atherosclerotic development, pro-inflammatory cytokines upregulation, and PPARγ/LXRα-ABCA1 downregulation. The same trend was observed in the stressed mice treatment with TAK-242. Further experimental evidences indicated that EP, TAK-242, and RSG treatment notably corrected foam cell formation, HMGB1 release, and down-regulation of LXRα and ABCA1 in CUMS Raw 264.7 macrophage model. Conclusion: These results indicate that CUMS exacerbates atherosclerosis is likely via HMGB1-mediated downregulation of PPARγ/LXRα-ABCA1 through TLR4. These data reveal a novel mechanism by which CUMS aggravates atherosclerosis and may offer a potential therapeutic target for this disease.

Spices and Atherosclerosis

Cardiovascular disease is one of the leading causes of death and disability in the world. Atherosclerosis, characterized by lipid accumulation and chronic inflammation in the vessel wall, is the main feature of cardiovascular disease. Although the amounts of fruits and vegetables present in the diets vary by country, diets, worldwide, contain large amounts of spices; this may have positive or negative effects on the initiation and development of atherosclerosis. In this review, we focused on the potential protective effects of specific nutrients from spices, such as pepper, ginger, garlic, onion, cinnamon and chili, in atherosclerosis and atherosclerotic cardiovascular disease. The mechanisms, epidemiological analysis, and clinical studies focusing on a variety of spices are covered in this review. Based on the integrated information, we aimed to raise specific recommendations for people with different dietary styles for the prevention of atherosclerotic cardiovascular disease through dietary habit adjustments.

Primary genetic disorders affecting high density lipoprotein (HDL)

There is extensive evidence demonstrating that there is a clear inverse correlation between plasma high density lipoprotein cholesterol (HDL-C) concentration and cardiovascular disease (CVD). On the other hand, there is also extensive evidence that HDL functionality plays a very important role in atheroprotection. Thus, genetic disorders altering certain enzymes, lipid transfer proteins, or specific receptors crucial for the metabolism and adequate function of HDL, may positively or negatively affect the HDL-C levels and/or HDL functionality and subsequently either provide protection or predispose to atherosclerotic disease. This review aims to describe certain genetic disorders associated with either low or high plasma HDL-C and discuss their clinical features, associated risk for cardiovascular events, and treatment options.

A method for high transfection efficiency in THP-1 suspension cells without PMA treatment

Adherent cells such as mouse RAW cells or human cancer U2OS cells are beneficial to DNA transfection, with 20%-60% transfection efficiency. However, this DNA transfection is rarely used on suspension cells due to its low transfection efficiency (≤5%). We recently found a new DNA transfection method to increase the efficiency up to 13.5% in suspension cells without PMA treatment. We also found that DNA transfection of human TNFAIP1 or CXCL1 recombinant plasmid DNA in THP-1 cells induces a high level of TNF-α protein. Overall, this new method is simple yet efficient and can be used for the overexpression of DNA in suspension cells.