NF-κB inhibitors that prevent foam cell formation and atherosclerotic plaque accumulation

Cellular and Molecular Mechanisms of Mast Cells in Atherosclerotic Plaque Progression and Destabilization

Mast cells (MCs) are commonly recognized for their crucial involvement in the pathogenesis of allergic diseases, but over time, it has come to light that they also play a role in the pathophysiology of non-allergic disorders including atherosclerosis. The involvement of MCs in the pathology of atherosclerosis is supported by their accumulation in atherosclerotic plaques upon their progression and the association of intraplaque MC numbers with acute cardiovascular events. MCs that accumulate within the atherosclerotic plaque release a cocktail of mediators through which they contribute to neovascularization, plaque progression, instability, erosion, rupture, and thrombosis. At a molecular level, MC-released proteases, especially cathepsin G, degrade low-density lipoproteins (LDL) and mediate LDL fusion and binding of LDL to proteoglycans (PGs). Through a complicated network of chemokines including CXCL1, MCs promote the recruitment of among others CXCR2+ neutrophils, therefore, aggravating the inflammation of the plaque environment. Additionally, MCs produce extracellular traps which worsen inflammation and contribute to atherothrombosis. Altogether, evidence suggests that MCs actively, via several underlying mechanisms, contribute to atherosclerotic plaque destabilization and acute cardiovascular syndromes, thus, making the study of interventions to modulate MC activation an interesting target for cardiovascular medicine.

Bergamot Byproducts: A Sustainable Source to Counteract Inflammation

Chronic inflammation is the result of an acute inflammatory response that fails to eliminate the pathogenic agent or heal the tissue injury. The consequence of this failure lays the foundations to the onset of several chronic ailments, including skin disorders, respiratory and neurodegenerative diseases, metabolic syndrome, and, eventually, cancer. In this context, the long-term use of synthetic anti-inflammatory drugs to treat chronic illnesses cannot be tolerated by patients owing to the severe side effects. Based on this, the need for novel agents endowed with anti-inflammatory effects prompted to search potential candidates also within the plant kingdom, being recognized as a source of molecules currently employed in several therapeutical areas. Indeed, the ever-growing evidence on the anti-inflammatory properties of dietary polyphenols traced the route towards the study of flavonoid-rich sources, such as Citrus bergamia (bergamot) and its derivatives. Interestingly, the recent paradigm of the circular economy has promoted the valorization of Citrus fruit waste and, in regard to bergamot, it brought to light new evidence corroborating the anti-inflammatory potential of bergamot byproducts, thus increasing the scientific knowledge in this field. Therefore, this review aims to gather the latest literature supporting the beneficial role of both bergamot derivatives and waste products in different models of inflammatory-based diseases, thus highlighting the great potentiality of a waste re-evaluation perspective.

Is the suppression of CD36 a promising way for atherosclerosis therapy?

Atherosclerosis is the main underlying pathology of many cardiovascular diseases and is marked by plaque formation in the artery wall. It has posed a serious threat to the health of people all over the world. CD36 acts as a significant regulator of lipid homeostasis, which is closely associated with the onset and progression of atherosclerosis and may be a new therapeutic target. The abnormal overexpression of CD36 facilitates lipid accumulation, foam cell formation, inflammation, endothelial apoptosis, and thrombosis. Numerous natural products and lipid-lowering agents are found to target the suppression of CD36 or inhibit the upregulation of CD36 to prevent and treat atherosclerosis. Here, the structure, expression regulation and function of CD36 in atherosclerosis and its related pharmacological therapies are reviewed. This review highlights the importance of drugs targeting CD36 suppression in the treatment and prevention of atherosclerosis, in order to develop new therapeutic strategies and potential anti-atherosclerotic drugs both preclinically and clinically.

Oridonin attenuates atherosclerosis by inhibiting foam macrophage formation and inflammation through FABP4/PPARγ signalling

Both lipid accumulation and inflammatory response in lesion macrophages fuel the progression of atherosclerosis, leading to high mortality of cardiovascular disease. A therapeutic strategy concurrently targeting these two risk factors is promising, but still scarce. Oridonin, the bioactive medicinal compound, is known to protect against inflammatory response and lipid dysfunction. However, its effect on atherosclerosis and the underlying molecular mechanism remain elusive. Here, we showed that oridonin attenuated atherosclerosis in hyperlipidemic ApoE knockout mice. Meanwhile, we confirmed the protective effect of oridonin on the oxidized low-density lipoprotein (oxLDL)-induced foam macrophage formation, resulting from increased cholesterol efflux, as well as reduced inflammatory response. Mechanistically, the network pharmacology prediction and further experiments revealed that oridonin dramatically facilitated the expression of peroxisome proliferator-activated receptor gamma (PPARγ), thereby regulating liver X receptor-alpha (LXRα)-induced ATP-binding cassette transporter A1 (ABCA1) expression and nuclear factor NF-kappa-B (NF-κB) translocation. Antagonist of PPARγ reversed the cholesterol accumulation and inflammatory response mediated by oridonin. Besides, RNA sequencing analysis revealed that fatty acid binding protein 4 (FABP4) was altered responding to lipid modulation effect of oridonin. Overexpression of FABP4 inhibited PPARγ activation and blunted the benefit effect of oridonin on foam macrophages. Taken together, oridonin might have potential to protect against atherosclerosis by modulating the formation and inflammatory response in foam macrophages through FABP4/PPARγ signalling.

Silica nanoparticles promoted pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling

Experimental evidence has pointed out silica nanoparticles (SiNPs) possessing a proatherogenic capability. However, the interplay between SiNPs and macrophages in the pathogenesis of atherosclerosis was poorly understood. Here, we demonstrated SiNPs could promote macrophage adhesion to endothelial cells, accompanied by elevated Vcam1 and Mcp1. Upon SiNPs stimuli, macrophages manifested enhanced phagocytic activity and a pro-inflammatory phenotype, as reflected by the transcriptional determination of M1/M2-related biomarkers. In particular, our data certified the increased macrophage M1 subset facilitated more lipid accumulation and resultant foam cell transformation in comparison to the M2 phenotype. More importantly, the mechanistic investigations revealed ROS-mediated PPARγ/NF-κB signaling was a key contributor to the above phenomena. That was, SiNPs caused ROS accumulation in macrophages, resulting in the deactivation of PPARγ, nuclear translocation of NF-κB, ultimately contributing to macrophage phenotype shift toward M1 and foam cell transformation. Collectively, we first revealed SiNPs facilitated pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling. These data would provide new insight into the atherogenic property of SiNPs in a macrophage model.

Lack of Rab27a attenuates foam cell formation and macrophage inflammation in uremic apolipoprotein E knockout mice

As the most common cardiovascular disease, atherosclerosis (AS), is a leading cause of high mortality in patients with chronic renal failure. Rab27a has been reported to regulate the progression of cardiovascular and renal diseases. Nevertheless, little studies investigated the role and mechanism of Rab27a in uremic-accelerated AS (UAAS). An animal model of UAAS was established in apolipoprotein E knockout (apoE^-/-) mice using 5/6 nephrectomy (NX). We conducted in vitro and in vivo functional experiments to explore the role of Rab27a in UAAS, including the presence of oxidized low-density lipoprotein (ox-LDL). Rab27a expression was upregulated in the plaque tissues of NX apoE^-/- mice. The knockout of Rab27a (Rab27a^-/-) reduced AS-induced artery injury, as manifested by the reductions of plaque area, collagen deposition, inflammation and lipid droplet. Besides, cholesterol efflux was increased, while the expression of lipid metabolism-related proteins and the secretions of pro-inflammatory factors were decreased in ox-LDL-induced NX Rab27a^-/- apoE^-/- mice group. Further, Rab27a deletion inhibited the activation of nuclear factor κB (NF-κB) pathway. In conclusion, our study indicated that Rab27a deficiency attenuated foam cell formation and macrophage inflammation, depending on the NF-κB pathway activation, to inhibit AS progression in uremic apoE^-/- mice. This finding may provide a new targeting strategy for UAAS therapy.

Efficiently Inhibiting Systemic Inflammatory Cascades by Fullerenes for Retarding HFD-Fueled Atherosclerosis

Atherosclerosis accounts for major mortality of cardiac-cerebral vascular diseases worldwide. Pathologically, persistent inflammation dominates the progression of atherosclerosis, which can be accelerated by a high-fat diet (HFD), possibly through triggering local intestinal oxidative stress and ensuing gut barrier dysfunction. Current pharmacotherapy has been disappointing, ascribed to limited therapeutic efficacy and undesirable side effects. Hence it is compelling to explore novel efficient anti-atherosclerotic drugs with minimal toxicity. Herein, two fullerene-based therapies with exceptional antioxidant capacity, in the form of water-soluble injectable fullerene nanoparticles (IFNPs) and oral fullerene tablets (OFTs), are demonstrated to retard HFD-fueled atherosclerosis in ApoE-/- mice with favorable biosafety. Especially, OFTs afford robust anti-atherosclerotic therapeutic even against advanced plaques, besides stabilizing plaques with less lipid deposition and improved collagen expression. Specifically, it is identified that OFTs can ameliorate HFD-induced dysregulated intestinal redox homeostasis and restore gut barrier integrity, thereby restraining the translocation of luminal lipopolysaccharide (LPS) into the bloodstream. Furthermore, significantly reduced circulating LPS after OFTs treatment contributes to down-regulated LPS/TLR4/NF-κB signaling in aortic focal, which further mitigates local inflammation and disease development. Overall, this study confirms the universal anti-atherosclerotic effect of fullerenes and provides a novel therapeutic mechanism via modulating intestinal barrier to attenuate atherosclerosis.

Polyphenolics from Syzygium brachythyrsum Inhibits Oxidized Low-Density Lipoprotein-Induced Macrophage-Derived Foam Cell Formation and Inflammation

Evidence suggests that the immunomodulatory property of polyphenols may also contribute to the reduction of cardiovascular risk. In the present study, we investigated the polyphenol extraction (PE) from Syzygium brachythyrsum, a functional food resource in south China, regarding the protective effect on inhibiting foam cell formation and the underlying molecular mechanism based on an ox-LDL-induced RAW264.7 macrophage model. The results of Oil Red O staining, Dil-ox-LDL fluorescent staining, and cholesterol efflux experiments showed that PE, and its two phenolics brachythol B (BB) and ethyl gallate (EG), significantly inhibited the foam cell formation, which may be associated with reducing the expression of SR-A1 and CD36 while increasing expression of SR-B1, ABCG1, and PPARγ. In addition, BB and EG also reduce the inflammatory response by down-regulating the expression of NF-κB and MAPK signal pathway proteins, thereby inhibiting the expression of inflammatory factors. Altogether, PE and its two components BB and EG attenuated foam cell formation and macrophage inflammation response.

NF-κB and its crosstalk with endoplasmic reticulum stress in atherosclerosis

Atherosclerosis (AS) is a common cardiovascular disease with complex pathogenesis, in which multiple pathways and their interweaving regulatory mechanism remain unclear. The primary transcription factor NF-κB plays a critical role in AS via modulating the expression of a series of inflammatory mediators under various stimuli such as cytokines, microbial antigens, and intracellular stresses. Endoplasmic reticulum (ER) stress, caused by the disrupted synthesis and secretion of protein, links inflammation, metabolic signals, and other cellular processes via the unfolded protein response (UPR). Both NF-κB and ER stress share the intersection regarding their molecular regulation and function and are regarded as critical individual contributors to AS. In this review, we summarize the multiple interactions between NF-κB and ER stress activation, including the UPR, NLRP3 inflammasome, and reactive oxygen species (ROS) generation, which have been ignored in the pathogenesis of AS. Given the multiple links between NF-κB and ER stress, we speculate that the integrated network contributes to the understanding of molecular mechanisms of AS. This review aims to provide an insight into these interactions and their underlying roles in the progression of AS, highlighting potential pharmacological targets against the atherosclerotic inflammatory process.

Isochlorogenic Acid C Alleviates High-Fat Diet-Induced Hyperlipemia by Promoting Cholesterol Reverse Transport

Background: Promoting cholesterol reverse transport (RCT) has been proven to be a promising hyperlipidemia therapy since it is more effective for the treatment of atherosclerosis (AS) caused by hyperlipidemia. Liver X receptor (LXR) agonists can accelerate RCT, but most of them trigger undesirable liver steatosis due to the activation of liver LXRα.

Aim: We aim to figure out whether isochlorogenic acid C (ICAC) facilitates RCT without causing hepatic steatosis.

Methods:In vitro study, we established foam macrophages and macrophages with loaded NBD-cholesterol models to investigate the competence of RCT promoting ICAC. RT-qPCR and Western blot were used to verify ICAC’s regulation of RCT and NF-κB inflammatory pathways. In this in vivo study, male 6-week-old C57BL/6 mice were fed a high-fat diet (HFD) to investigate ICAC’s anti-hyperlipidemic effect and its functions in regulating RCT. The anti-hyperlipidemic effect of ICAC was evaluated by blood and liver lipid levels, liver hematoxylin, oil red o staining, and liver coefficient. Finally, mRNA levels of genes involved in RCT and inflammation pathways in the liver and intestine were detected by RT-qPCR.

Results: ICAC prevented macrophages from foaming by up-regulating the LXRα mediated RCT pathway and down-regulating expression of the cholesterol absorption genes LDLR and CD36, as well as suppressing iNOS, COX2, and IL-1β inflammatory factors. In HFD-fed mice, ICAC significantly lowered the lipid level both in the serum and the liver. Mechanistic studies showed that ICAC strengthened the RCT pathway in the liver and intestine but didn’t affect liver LXRα. Furthermore, ICAC impeded both adipogenesis and the inflammatory response in the liver.

Conclusion: ICAC accelerated RCT without affecting liver LXRα, thus resulting in a lipid-lowering effect without increasing liver adipogenesis. Our results indicated that ICAC could be a new RCT promoter for hyperlipidemia treatment without causing liver steatosis.

Modified Yuejuwan Inhibited Cholesterol Accumulation and Inflammation in THP-1 Macrophage-Derived Foam Cells by Inhibiting the Activity of the TRIM37/TRAF2/NF-κB Pathway

Background

This study aimed to explore the function of modified Yuejuwan (MYJ) on THP-1 macrophage-derived foam cells.

Methods

First, human THP-cells were obtained, and then, grouping was made to the following: control group, foaming group, foaming group +0.2 mg/mL Jiawei Yueju pill, foaming group +0.5 mg/mL Jiawei Yueju pill, and foaming group +1 mg/mL Jiawei Yueju pill. An Oil Red O staining assay was used to examine the uptake of oxidatively modified low-density lipoprotein (oxLDL). The secretion of interleukin (IL)-1β and tumor necrosis factor (TNF)-α were determined using an enzyme-linked immunosorbent assay (ELISA). Real-time quantitative PCR (qRT-PCR) and Western blot were used to quantify genes and proteins expression levels.

Results

Our results indicated that MYJ inhibited the accumulation of total cholesterol (TC), free cholesterol (FC), and cholesteryl ester (CE) in foam cells. Moreover, the secretion of IL-1β and TNF-α also downregulated in foam cells after treatment of MYJ. Furthermore, we found that tripartite motif-containing 37 (TRIM37) was significantly upregulated in foam cells. Knockdown of TRIM37 promoted cholesterol efflux and presented an anti-inflammation effect in foam cells. Furthermore, TRIM37 positively mediated the translocation of NF-κB to nuclear. It negatively regulated its ubiquitination in foam cells after interacting with TRAF2. Importantly, MYJ profoundly suppressed the function of TRIM37 in foam cells and functioned as a TRIM37 inhibitor.

Conclusions

This study demonstrated that MYJ might alleviate oxLDL-induced foam cell formation by inhibiting the TRIM37/TRAF2/NF-κB pathway activity. MYJ was a potential agent in preventing atherosclerosis and indicated its potential signaling pathway in foam cells.

Long Noncoding RNA MIAT Controls Advanced Atherosclerotic Lesion Formation and Plaque Destabilization

Supplemental Digital Content is available in the text.

Long noncoding RNAs (lncRNAs) are important regulators of biological processes involved in vascular tissue homeostasis and disease development. The present study assessed the functional contribution of the lncRNA myocardial infarction-associated transcript (MIAT) to atherosclerosis and carotid artery disease.

Paeonia lactiflora Root Extract and Its Components Reduce Biomarkers of Early Atherosclerosis via Anti-Inflammatory and Antioxidant Effects In Vitro and In Vivo

Although various physiological activities of compounds obtained from Paeonia lactiflora have been reported, the effects of P. lactiflora extract (PLE) on early atherosclerosis remain unclear. Therefore, in this study, we investigated the in vitro and in vivo antiatherosclerosis and in vitro antioxidant effects of PLE and its compounds. PLE suppresses the tumor necrosis factor (TNF)-α-induced capacity of THP-1 cells to adhere to human umbilical vein endothelial cells (HUVECs), vascular cell adhesion molecule (VCAM)-1 expression, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in HUVECs. PLE also suppresses TNF-α-induced nuclear translocation of NF-κB p65 from cytosol as well as the enhanced TNFA and C-C motif chemokine ligand 2 (CCL2) mRNA expression in HUVECs. We identified and quantified the following PLE compounds using high-performance liquid chromatography with diode array detection: methyl gallate, oxypaeoniflorin, catechin, albiflorin, paeoniflorin, benzoic acid, benzoylpaeoniflorin, and paeonol. Among these, methyl gallate had the strongest inhibitory effect on monocyte adherence to TNF-α-induced HUVECs and the VCAM-1 expression. Reverse transcriptase real-time quantitative polymerase chain reaction showed that PLE compounds had a dissimilar inhibition effect on TNF-α-induced mRNA expression levels of CCL2, TNFA, and IL6 in HUVECs. Except for paeonol, the compounds inhibited lipopolysaccharide (LPS)-induced reactive oxygen species production in RAW264.7 cells. In vivo, oral administration of PLE improved TNF-α-induced macrophage infiltration to the vascular endothelium and expression of VCAM-1, as well as IL6 and TNFA gene expression in the main artery of mice. PLE could be useful as a nutraceutical material against early atherosclerosis via the combined effects of its components.

Co-Delivery of Curcumin and Bioperine via PLGA Nanoparticles to Prevent Atherosclerotic Foam Cell Formation

Cholesterol-rich arterial plaques characterize atherosclerosis, a significant cause of heart disease. Nutraceuticals have received attention over the years, demonstrating potential benefits towards treating and preventing cardiovascular diseases (CVD), including atherosclerosis. Curcumin, a potent polyphenol present in Curcuma longa, has shown remarkable anti-atherosclerotic activity via anti-inflammatory and anti-oxidative properties. The bioavailability and low water solubility of curcumin limit its clinical translational purposes. These issues can be circumvented effectively by nano-drug delivery systems that can target atherosclerotic plaque sites. In this work, we chose to use curcumin and a natural bioenhancer called Bioperine (derived from Piper nigrum) inside a polymeric nano-drug delivery system for targeting atherosclerotic plaque sites. We selected two different ratios of curcumin:Bioperine to study its comparative effect on the inhibition of oxidized low-density lipoprotein (Ox-LDL)-induced foam cell formation. Our studies demonstrated that Cur-Bio PLGA NPs (both ratios) maintained the cell viability in THP-1 monocyte-derived macrophages above 80% at all periods. The 1:0.2:10 ratio of Cur-Bio PLGA NPs at a concentration of 250 μg/mL illustrated an enhanced reduction in the relative cholesterol content in the THP-1-derived foam cells compared to the 1:1:10 ratio. Confocal microscopy analysis also revealed a reduction in macrophage-mediated foam cell formation when administered with both the ratios of Cur-Bio PLGA NPs. Relative fold change in the mRNA expression of the genes involved in the inflammatory pathways in the atherosclerotic process downregulated NF-κB, CCL2/MCP-1, CD-36, and STAT-3 activity while upregulating the SCAR-B1 expression when treated with the Cur-Bio PLGA NPs. This study thus highlights the importance of natural-based compounds towards the therapeutic intervention against atherosclerotic activity when administered as preventive medicine.

SR-A-Targeted Nanoplatform for Sequential Photothermal/Photodynamic Ablation of Activated Macrophages to Alleviate Atherosclerosis

Cardiovascular and cerebrovascular diseases induced by atherosclerosis (AS) have become the dominant cause of disability and mortality throughout the world. The typical early pathological process of AS involves the activation of inflammatory macrophages in the vulnerable plaque. In this work, we first employed chitosan-coated carbon nanocages (CS-CNCs) as nanocarriers to load Chlorin e6 (Ce6) and then linked dextran sulfate (DS) to the outermost layer by electrostatic adsorption to create a multifunctional therapeutic nanoplatform, CS-CNCs@Ce6/DS. The DS of the nanoplatform can recognize and bind to the type A scavenger receptor (SR-A), which is expressed only on the activated macrophages of the arterial plaque, so the proposed nanoplatform selectively targets these macrophages and accumulates there. Furthermore, DS can competitively inhibit cellular endocytosis of oxidized low-density lipoproteins via blocking of SR-A. The rapid photothermal conversion capability of CS-CNCs enables efficient therapeutic delivery during photothermal therapy (PTT). Interestingly, near-infrared-accelerated drug release induced by initial 808-nm laser irradiation was observed, thus enhancing the Ce6 concentration in the atherosclerotic plaque area and the efficiency of photodynamic therapy (PDT). Sequential photothermal/photodynamic ablation of the activated macrophages reduced pro-inflammatory cytokine secretion and alleviated the proliferation and migration of smooth muscle cells. These finally resulted in the stabilization and shrinkage of atherosclerotic plaques, further inhibiting the development and exacerbation of AS. Therefore, this work achieved a "1 + 1 greater than 2" effect by providing a novel approach to the treatment of atherosclerotic plaques, which is promising for the prevention of AS-related diseases.

Recent advances in nanomaterials for therapy and diagnosis for atherosclerosis

Atherosclerosis is a chronic inflammatory disease driven by lipid accumulation in arteries, leading to narrowing and thrombosis. It affects the heart, brain, and peripheral vessels and is the leading cause of mortality in the United States. Researchers have strived to design nanomaterials of various functions, ranging from non-invasive imaging contrast agents, targeted therapeutic delivery systems to multifunctional nanoagents able to target, diagnose, and treat atherosclerosis. Therefore, this review aims to summarize recent progress (2017-now) in the development of nanomaterials and their applications to improve atherosclerosis diagnosis and therapy during the preclinical and clinical stages of the disease.

Ginsenoside Compound K Attenuates Ox-LDL-Mediated Macrophage Inflammation and Foam Cell Formation via Autophagy Induction and Modulating NF-κB, p38, and JNK MAPK Signaling

Atherosclerosis is a major reason for the high morbidity and mortality of cardiovascular diseases. Macrophage inflammation and foam cell formation are the key pathological processes of atherosclerosis. Ginsenoside compound K (CK) is a metabolite derived from ginseng. CK has anti atherosclerotic effect, but the molecular mechanism remains to be elucidated. We aim to explore the protective effect of CK against ox-LDL-induced inflammatory responses and foam cells formation in vitro and explore its potential mechanisms. Through the results of oil red O staining, Western blot, and qPCR, we found that CK significantly inhibited the foam cell formation, reduced the expression of SR-A1 and increased ABCA1 and ABCG1 expression. In addition, CK increased the number of autophagosomes and upregulated the LC3II/LC3I ratio and the expressions of ATG5 and Beclin-1 but decreased p62 expression. Moreover, CK significantly inhibited the NF-κB, p38, and JNK MAPK signaling pathway. Altogether, CK attenuated macrophage inflammation and foam cell formation via autophagy induction and by modulating NF-κB, p38, and JNK MAPK signaling. Thus, CK has potential as a therapeutic drug for atherosclerosis.

Salvianolic Acid A Ameliorates Early-Stage Atherosclerosis Development by Inhibiting NLRP3 Inflammasome Activation in Zucker Diabetic Fatty Rats

Salvianolic acid A (SAA), an important bioactive polyphenolic acid found in Salvia miltiorrhiza Bunge, may be used for treating metabolic disorders due to its anti-inflammatory activity. Since chronic inflammation plays an important role in type 2 diabetes mellitus (T2DM) complicated with atherosclerosis (AS), SAA may have beneficial effects on AS. Here, we evaluated the effects of SAA on metabolic disorders in male Zucker diabetic fatty (ZDF) rats induced by a high-fat diet and Vitamin D3 injections. Compared with the model group, the SAA high dosage (1 mg/kg) group exhibited decreased hemoglobin A1C levels but unchanged blood glucose levels. The disrupted lipid profiles were ameliorated by SAA, with significantly decreased levels of blood cholesterol, LDL-C and triglyceride. The protective effects of SAA against early AS were further confirmed by histopathological examination of aortic tissues. In addition, we observed that SAA decreased serum hs-CRP levels and suppressed the activation of NLRP3 inflammasome and NF-κB signaling in aortic tissues of ZDF rats. Collectively, our results demonstrate the potential of SAA to alleviate AS and T2DM in ZDF rats as a result of its anti-inflammatory effects.

Lipocalin-2 exerts pro-atherosclerotic effects as evidenced by in vitro and in vivo experiments

Lipocalin-2 (LCN2), a multiple bioactive hormone particularly expressed in adipose tissue, neutrophils, and macrophages, is known to exhibit anti-microbial effect, increase inflammatory cytokine levels, and maintain glucose homeostasis. Serum LCN2 level is positively correlated with the severity of coronary artery disease. However, it still remains unknown whether LCN2 affects atherogenesis. We assessed the effects of LCN2 on the inflammatory response and monocyte adhesion in human umbilical vein endothelial cells (HUVECs), inflammatory phenotype and foam cell formation in THP1 monocyte-derived macrophages, and migration and proliferation of human aortic smooth muscle cells (HASMCs) in vitro and aortic lesions in Apoe^-/- mice in vivo. LCN2 and its receptor, low-density lipoprotein (LDL)-related protein-2, were expressed in THP1 monocytes, macrophages, HASMCs, and HUVECs. LCN2 significantly enhanced THP1 monocyte adhesion to HUVECs accompanied with upregulation of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin associated with nuclear factor-κB (NF-κB) upregulation in HUVECs. LCN2 significantly increased HUVEC proliferation and oxidized LDL-induced foam cell formation in THP1 monocyte-derived macrophages. LCN2 significantly increased the inflammatory M1 phenotype associated with NF-κB upregulation during differentiation of THP1 monocytes into macrophages. In HASMCs, LCN2 significantly promoted the migration and collagen-1 expression without inducing proliferation, which are associated with increased protein expression of phosphoinositide 3-kinase and phosphorylation of Akt, extracellular signal-regulated kinase, c-jun-N-terminal kinase, and NF-κB. Chronic LCN2 infusion into Apoe^-/- mice significantly accelerated the development of aortic atherosclerotic lesions, with increased intraplaque monocyte/macrophage infiltration and pentraxin-3 and collagen-1 expressions. Our results suggested that LCN2 accelerates the development of atherosclerosis. Thus, LCN2 could serve as a novel therapeutic target for atherosclerotic diseases.

Rapamycin and FTY720 Alleviate Atherosclerosis by Cross Talk of Macrophage Polarization and Autophagy

Foam cell formation and macrophage polarization are involved in the pathologic development of atherosclerosis, one of the most important human diseases affecting large and medium artery walls. This study was designed to assess the effects of rapamycin and FTY720 (fingolimod) on macrophages and foam cells. Mouse peritoneal macrophages were collected and treated with rapamycin and FTY720 to study autophagy, polarization, and lipid accumulation. Next, foam cells were formed by oxidizing low-density lipoprotein to observe changes in lipid accumulation, autophagy, and polarization in rapamycin-treated or FTY720-treated foam cells. Lastly, foam cells that had been treated with rapamycin and FTY720 were evaluated for sphingosine 1-phosphate receptor (S1prs) expression. Autophagy microtubule-associated protein 1 light chain 3- (LC3-) II was increased, and classically activated macrophage phenotype markers interleukin- (IL-) 6, cyclooxygenase-2 (COX2), and inducible nitric oxide synthase (iNOS) were increased, whereas alternatively activated macrophage phenotype markers transforming growth factor- (TGF-) β, arginase 1 (Arg1), and mannose receptor C-type 1 (Mrc1) were decreased by rapamycin in peritoneal macrophages. LC3-II was also obviously enhanced, though polarization markers were unchanged in rapamycin-treated foam cells. Moreover, lipid accumulation was inhibited in rapamycin-treated macrophage cells but was unchanged in rapamycin-treated foam cells. For FTY720, LC3-II did not change, whereas TGF-β, Arg1 and Mrc1 were augmented, and IL-6 was suppressed in macrophages. However, LC3-II was increased, and TGF-β, ARG1 and MRC1 were strikingly augmented, whereas IL-6, COX2 and iNOS could be suppressed in foam cells. Furthermore, lipid accumulation was alleviated in FTY720-treated foam cells. Additionally, S1pr1 was markedly decreased in foam cells (P < .05); S1pr2, S1pr3, S1pr4 and S1pr5 were unchanged in rapamycin-treated foam cells. In FTY720-treated foam cells, S1pr3 and S1pr4 were decreased, and S1pr1, S1pr2 and S1pr5 were unchanged. Therefore, we deduced that rapamycin stimulated classically activated macrophages and supressed early atherosclerosis. Rapamycin may also stabilize artery plaques by preventing apoptosis and S1PR1 in advanced atherosclerosis. FTY720 allowed transformation of foam cells into alternatively activated macrophages through the autophagy pathway to alleviate advanced atherosclerosis.

Ginkgolide B inhibits platelet and monocyte adhesion in TNFα-treated HUVECs under laminar shear stress

Background

Endothelial cells are sensitive to changes in both blood components and mechanical stimuli. Endothelial cells may undergo phenotypic changes, such as changes in adhesion protein expression, under different shear stress conditions. Such changes may impact platelet and monocyte adhesion to endothelial cells. This phenomenon is linked to chronic vascular inflammation and the development of atherosclerosis. In the present study, we investigated the effects of ginkgolide B on platelet and monocyte adhesion to human umbilical vein endothelial cells (HUVECs) under different conditions of laminar shear stress.

Methods

Platelet and monocyte adhesion to endothelial cells was determined by the Bioflux 1000. HUVECs were incubated with ginkgolide B or aspirin for 12 h, and then TNFα was added for 2 h to induce the inflammatory response under conditions of 1 and 9 dyn/cm² laminar shear stress. The protein expression was analyzed by Western blot.

Results

The number of platelets that adhered was greater under conditions of 1 dyn/cm² than under conditions of 9 dyn/cm² of laminar shear stress (74.8 ± 19.2 and 59.5 ± 15.1, respectively). Ginkgolide B reduced the tumor necrosis factor α (TNFα)-induced increase in platelet and monocyte adhesion to HUVECs at 1 and 9 dyn/cm² of laminar shear stress. In TNFα-treated HUVECs, the number of monocytes that adhered was greater under conditions of 1 dyn/cm² of laminar shear stress compared with 9 dyn/cm² (29.1 ± 4.9 and 22.7 ± 3.7, respectively). Ginkgolide B inhibited the TNFα-induced expression of vascular cell adhesion molecule-1(VCAM-1), VE-cadherin, and Cx43 in HUVECs at 1 and 9 dyn/cm². The expression of these proteins was not different between 1 and 9 dyn/cm².

Conclusions

Ginkgolide B suppressed platelet and monocyte adhesion under different conditions of laminar shear stress. Moreover, ginkgolide B reduced VCAM-1, VE-cadherin and Cx43 expression in TNFα-treated HUVECs under laminar shear stress. This suggested that ginkgolide B might shed light on the treatment of inflammation in atherosclerosis.

Identification of Gene Expression Changes in the Aorta of ApoE Null Mice Fed a High-Fat Diet

Atherosclerosis is a chronic multifactorial inflammatory disease with high worldwide prevalence, and has become the leading cause of death. In the present study, we analyzed global gene expression changes in the aorta of Apolipoprotein E (ApoE) null mice fed a high-fat diet by using RNA-seq. We identified a total of 280 differentially expressed genes, of which 163 genes were upregulated and 117 genes were downregulated by high-fat diet compared with normal diet. Functional clustering and gene network analysis revealed that fatty acid metabolic process is crucial for atherosclerosis. By examining of the promoter regions of differentially expressed genes, we identified four causal transcription factors. Additionally, through connectivity map (CMap) analysis, multiple compounds were identified to have anti-atherosclerotic effects due to their ability to reverse gene expression during atherosclerosis. Our study provides a valuable resource for in-depth understanding of the mechanism underlying atherosclerosis.