A comparative study of the hypolipidemic effects and mechanisms of action of Laminaria japonica- and Ascophyllum nodosum-derived fucoidans in apolipoprotein E-deficient mice.

The structural characteristics of fucoidans exhibit species and regional diversity. Previous studies have demonstrated that Laminaria japonica- and Ascophyllum nodosum-derived fucoidans have type I and type II fucosyl chains, respectively. These chemical differences may contribute to distinct hypolipidemic effects and mechanisms of action. Chemical analysis demonstrated that the percentage contents of sulfate, glucuronic acid, and galactose were higher in L. japonica-derived fucoidans than those of A. nodosum-derived fucoidans. In hyperlipidemic apolipoprotein E-deficient mice, both A. nodosum- and L. japonica-derived fucoidans significantly decreased the plasma and hepatic levels of total cholesterol and triglyceride, leading to the reduction of atherosclerotic plaques. Western blotting experiments demonstrated that these fucoidans significantly enhanced the expression and levels of scavenger receptor B type 1, cholesterol 7 alpha-hydroxylase A1, and peroxisome proliferator-activated receptor (PPAR)-α, contributing to circulating lipoprotein clearance and fatty acid degradation, respectively. Differentially, L. japonica-derived fucoidan significantly increased the LXR/ATP-binding cassette G8 signaling pathway in the small intestine, as revealed by real-time quantitative PCR, which may lead to further cholesterol and other lipid excretion. Collectively, these data are useful for understanding the hypolipidemic mechanisms of action of seaweed-derived fucoidans, and their potential application for the prevention and/or treatment of atherosclerotic cardiovascular diseases.

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation.

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

Laminaria japonica Aresch-Derived Fucoidan Ameliorates Hyperlipidemia by Upregulating LXRs and Suppressing SREBPs.

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and hyperlipidemia is one major inducing factor of CVD. It is worthy to note that fucoidans are reported to have hypolipidemic activity with species specificity; however, the underlying mechanisms of action are far from clarification. This study is aimed at investigating the plasma lipid-lowering mechanisms of the fucoidan from L. japonica Aresch by detecting the levels of hepatic genes that are involved in lipid metabolism. Our results demonstrated that the fucoidan F3 significantly lowered total cholesterol and triglyceride in C57BL/6J mice fed a high-fat diet. In the mouse liver, fucoidan F3 intervention significantly increased the gene expression of peroxisome proliferator-activated receptor (PPAR) α, liver X receptor (LXR) α and ß, and ATP-binding cassette transporter (ABC) G1 and G8 and decreased the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), low-density lipoprotein receptor, cholesterol 7 alpha-hydroxylase A1, and sterol regulatory element-binding protein (SREBP) 1c and SREBP-2. These results demonstrated that the antihyperlipidemic effects of fucoidan F3 are related to its activation of PPARα and LXR/ABC signaling pathways and inactivation of SREBPs. In conclusion, fucoidan F3 may be explored as a potential compound for prevention or treatment of lipid disorders.

Targeting PPARs for therapy of atherosclerosis: A review.

Atherosclerosis, a chief pathogenic factor of cardiovascular disease, is associated with many factors including inflammation, dyslipidemia, and oxidative stress. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors and are widely expressed with tissue- and cell-specificity. They control multiple genes that are involved in lipid metabolism, inflammatory response, and redox homeostasis. Given the diverse biological functions of PPARs, they have been extensively studied since their discovery in 1990s. Although controversies exist, accumulating evidence have demonstrated that PPAR activation attenuates atherosclerosis. Recent advances are valuable for understanding the mechanisms of action of PPAR activation. This article reviews the recent findings, mainly from the year of 2018 to present, including endogenous molecules in regulation of PPARs, roles of PPARs in atherosclerosis by focusing on lipid metabolism, inflammation, and oxidative stress, and synthesized PPAR modulators. This article provides information valuable for researchers in the field of basic cardiovascular research, for pharmacologists that are interested in developing novel PPAR agonists and antagonists with lower side effects as well as for clinicians.

CM3-SII polysaccharide obtained from Cordyceps militaris ameliorates hyperlipidemia in heterozygous LDLR-deficient hamsters by modulating gut microbiota and NPC1L1 and PPARα levels.

Accumulating evidence has demonstrated that polysaccharides derived from edible fungi have lipid-lowering effects in mice. However, the lipid metabolism mechanisms in mice and humans are different. We have previously elucidated the structural characteristics of the alkali-extracted polysaccharide CM3-SII obtained from Cordyceps militaris. This study aimed to investigate whether CM3-SII could ameliorate hyperlipidemia in a heterozygous low-density lipoprotein receptor (LDLR)-deficient hamster model of hyperlipidemia. Our data demonstrated that CM3-SII significantly decreased total plasma cholesterol, non-high-density lipoprotein cholesterol, and triglyceride levels in heterozygous LDLR-deficient hamsters. Unlike ezetimibe, CM3-SII could enhance the concentration of plasma apolipoprotein A1 and the expression of liver X receptor α/ATP-binding cassette transporter G8 mRNA pathway and suppress the expression of Niemann-Pick C1-like 1, which help to reduce cholesterol levels further. Moreover, the results of molecular docking analysis demonstrated that CM3-SII could directly bind to Niemann-Pick C1-like 1 with high affinity. The triglyceride-lowering mechanisms of CM3-SII were related to its downregulation of sterol regulatory element-binding protein 1c and upregulation of peroxisome proliferator-activated receptor α. Importantly, CM3-SII increased the abundance of Actinobacteria and Faecalibaculum and the ratio of Bacteroidetes/Firmicutes. Thus, CM3-SII attenuated hyperlipidemia by modulating the expression of multiple molecules involved in lipid metabolism and the gut microbiota.

Targeting macrophages in atherosclerosis using nanocarriers loaded with liver X receptor agonists: A narrow review.

Macrophages are involved in the whole process of atherosclerosis, which is characterized by accumulation of lipid and inflammation. Presently, clinically used lipid-lowering drugs cannot completely retard the progress of atherosclerosis. Liver X receptor (LXR) plays a key role in regulation of lipid metabolism and inflammation. Accumulating evidence have demonstrated that synthetic LXR agonists can significantly retard the development of atherosclerosis. However, these agonists induce sever hypertriglyceridemia and liver steatosis. These side effects have greatly limited their potential application for therapy of atherosclerosis. The rapid development of drug delivery system makes it possible to delivery interested drugs to special organs or cells using nanocarriers. Macrophages express various receptors which can recognize and ingest specially modified nanocarriers loaded with LXR agonists. In the past decades, a great progress has been made in this field. These macrophage-targeted nanocarriers loaded with LXR agonists are found to decrease atherosclerosis by reducing cholesterol accumulation and inflammatory reactions. Of important, these nanocarriers can alleviate side effects of LXR agonists. In this article, we briefly review the roles of macrophages in atherosclerosis, mechanisms of action of LXR agonists, and focus on the advances of macrophage-targeted nanocarriers loaded with LXR agonists. This work may promote the potential clinical application of these nanocarriers.

Sea cucumber-derived compounds for treatment of dyslipidemia: A review.

Dyslipidemias are disorders of plasma levels of lipids, such as elevated levels of total cholesterol and triglyceride, that are associated with various human diseases including cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). Statins are the first-line drugs for treatment of dyslipidemia. However, a substantial proportion of patients cannot reach the recommended LDL-c level even with the highest tolerated doses of statins, and there is no available drug specifically for NAFLD therapy. Sea cucumbers are one of the widely distributed invertebrates, and are an important resource of food and medicine. Sea cucumbers have many valuable nutrients including saponins, fatty acids, phospholipids, cerebrosides, sulfated polysaccharides, as well as proteins and peptides. In recent years, these natural products derived from sea cucumbers have attracted attentions for treatment of CVD and NAFLD because of their lipid-lowering effect and low toxicity. However, the hypolipidemic mechanisms of action and the structure-activity relationship of these bioactive components have not been well-documented in literature. This review article summarizes the signaling pathways and the potential structure-activity relationship of sea cucumber-derived bioactive compounds including saponins, lipids, carbohydrates as well as peptides and proteins. This article will provide information useful for the development of sea cucumber-derived lipid-lowering compounds as well as for investigation of hypolipidemic compounds that are derived from other natural resources.

Low-density lipoprotein particles in atherosclerosis.

Among the diseases causing human death, cardiovascular disease (CVD) remains number one according to the World Health Organization report in 2021. It is known that atherosclerosis is the pathological basis of CVD. Low-density lipoprotein (LDL) plays a pivotal role in the initiation and progression of atherosclerotic CVD (ASCVD). LDL cholesterol (LDL-C) is the traditional biological marker of LDL. However, large numbers of patients who have achieved the recommended LDL-C goals still have ASCVD risk. In multiple prospective studies, LDL particle (LDL-P) is reported to be more accurate in predicting CVD risk than LDL-C. LDL-Ps differ in size, density and chemical composition. Numerous clinical studies have proved that the atherogenic mechanisms of LDL-Ps are determined not only by LDL number and size but also by LDL modifications. Of note, small dense LDL (sdLDL) particles possess stronger atherogenic ability compared with large and intermediate LDL subfractions. Besides, oxidized LDL (ox-LDL) is another risk factor in atherosclerosis. Among the traditional lipid-lowering drugs, statins induce dramatic reductions in LDL-C and LDL-P to a lesser extend. Recently, proprotein convertase subtilsin/kexin type 9 inhibitors (PCSK9i) have been demonstrated to be effective in lowering the levels of LDL-C, LDL-P, as well as CVD events. In this article, we will make a short review of LDL metabolism, discuss the discordance between LDL-C and LDL-P, outline the atherogenic mechanisms of action of LDL by focusing on sdLDL and ox-LDL, summarize the methods used for measurement of LDL subclasses, and conclude the advances in LDL-lowering therapies using statins and PCSK9i.

Fenofibrate enhances lipid deposition via modulating PPARγ, SREBP-1c, and gut microbiota in ob/ob mice fed a high-fat diet.

Obesity is characterized by lipid accumulation in distinct organs. Presently, fenofibrate is a commonly used triglyceride-lowering drug. This study is designed to investigate whether long-term fenofibrate intervention can attenuate lipid accumulation in ob/ob mouse, a typical model of obesity. Our data demonstrated that fenofibrate intervention significantly decreased plasma triglyceride level by 21.0%, increased liver index and hepatic triglyceride content by 31.7 and 52.1%, respectively, and elevated adipose index by 44.6% compared to the vehicle group. As a PPARα agonist, fenofibrate intervention significantly increased the expression of PPARα protein in the liver by 46.3% and enhanced the expression of LDLR protein by 3.7-fold. However, fenofibrate dramatically increased the expression of PPARγ and SREBP-1c proteins by ~2.1- and 0.9-fold in the liver, respectively. Fenofibrate showed no effects on the expression of genes-related to fatty acid ß-oxidation. Of note, it significantly increased the gene expression of FAS and SCD-1. Furthermore, fenofibrate modulated the gut microbiota. Collectively, long-term fenofibrate induces lipid accumulation in liver and adipose tissues in ob/ob mice by enhancing the expression of adipogenesis-related proteins and gut microbiota. These data suggest that fenofibrate may have limited effects on attenuating lipid deposition in obese patients.

Triglyceride and Triglyceride-Rich Lipoproteins in Atherosclerosis.

Cardiovascular disease (CVD) is still the leading cause of death globally, and atherosclerosis is the main pathological basis of CVDs. Low-density lipoprotein cholesterol (LDL-C) is a strong causal factor of atherosclerosis. However, the first-line lipid-lowering drugs, statins, only reduce approximately 30% of the CVD risk. Of note, atherosclerotic CVD (ASCVD) cannot be eliminated in a great number of patients even their LDL-C levels meet the recommended clinical goals. Previously, whether the elevated plasma level of triglyceride is causally associated with ASCVD has been controversial. Recent genetic and epidemiological studies have demonstrated that triglyceride and triglyceride-rich lipoprotein (TGRL) are the main causal risk factors of the residual ASCVD. TGRLs and their metabolites can promote atherosclerosis via modulating inflammation, oxidative stress, and formation of foam cells. In this article, we will make a short review of TG and TGRL metabolism, display evidence of association between TG and ASCVD, summarize the atherogenic factors of TGRLs and their metabolites, and discuss the current findings and advances in TG-lowering therapies. This review provides information useful for the researchers in the field of CVD as well as for pharmacologists and clinicians.

Structural Elucidation and Activities of Cordyceps militaris-Derived Polysaccharides: A Review.

Cordyceps militaris is a parasitic edible fungus and has been used as tonics for centuries. Polysaccharides are a major water-soluble component of C. militaris. Recently, C. militaris-derived polysaccharides have been given much attention due to their various actions including antioxidant, anti-inflammatory, anti-tumor, anti-hyperlipidemic, anti-diabetic, anti-atherosclerotic, and immunomodulatory effects. These bioactivities are determined by the various structural characteristics of polysaccharides including monosaccharide composition, molecular weight, and glycosidic linkage. The widespread use of advanced analytical analysis tools has greatly improved the elucidation of the structural characteristics of C. militaris-derived polysaccharides. However, the methods for polysaccharide structural characterization and the latest findings related to C. militaris-derived polysaccharides, especially the potential structure-activity relationship, have not been well-summarized in recent reviews of the literature. This review will discuss the methods used in the elucidation of the structure of polysaccharides and structural characteristics as well as the signaling pathways modulated by C. militaris-derived polysaccharides. This article provides information useful for the development of C. militaris-derived polysaccharides as well as for investigating other medicinal polysaccharides.

The polysaccharide-peptide complex from mushroom Cordyceps militaris ameliorates atherosclerosis by modulating the lncRNA-miRNA-mRNA axis.

An N-glycosidic polysaccharide-peptide complex CMPS-80 was obtained from the fruiting body of C. militaris. Of importance, CMPS-80 significantly ameliorated formation of atherosclerotic lesions and plasma lipid profiles in apolipoprotein E-deficient mice. Integrated informatics analysis suggested that CMPS-80 can modulate multiple lncRNA-microRNA-mRNA axes. CMPS-80 has a potential application for prevention of hyperlipidemia and atherosclerosis.

Targeting the PDGF/PDGFR signaling pathway for cancer therapy: A review.

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are expressed in a variety of tumors. Activation of the PDGF/PDGFR signaling pathway is associated with cancer proliferation, metastasis, invasion, and angiogenesis through modulating multiple downstream pathways, including phosphatidylinositol 3 kinase/protein kinase B pathway and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Therefore, targeting PDGF/PDGFR signaling pathway has been demonstrated to be an effective strategy for cancer therapy, and accordingly, some great progress has been made in this field in the past few decades. This review will focus on the PDGF isoforms and their binding with the related PDGFRs, the PDGF/PDGFR signaling and regulation, and especially present strategies and inhibitors developed for cancer therapy, and the related clinical benefits and side effects.

Polysaccharide CM1 from Cordyceps militaris hinders adipocyte differentiation and alleviates hyperlipidemia in LDLR(+/-) hamsters.

BACKGROUND: Cordyceps militaris is cultured widely as an edible mushroom and accumulating evidence in mice have demonstrated that the polysaccharides of Cordyceps species have lipid-lowering effects. However, lipid metabolism in mice is significantly different from that in humans, making a full understanding of the mechanisms at play critical. METHODS: After 5 months, the hamsters were weighed and sampled under anesthesia after overnight fasting. The lipid-lowering effect and mechanisms of the polysaccharide CM1 was investigated by cellular and molecular technologies. Furthermore, the effect of the polysaccharide CM1 (100 µg/mL) on inhibiting adipocyte differentiation was investigated in vitro. RESULTS: CM1, a polysaccharide from C. militaris, significantly decreased plasma total cholesterol, triglyceride and epididymal fat index in LDLR(+/-) hamsters, which have a human-like lipid profile. After 5 months' administration, CM1 decreased the plasma level of apolipoprotein B48, modulated the expression of key genes and proteins in liver, small intestine, and epididymal fat. CM1 also inhibited preadipocyte differentiation in 3T3-L1 cells by downregulating the key genes involved in lipid droplet formation. CONCLUSIONS: The polysaccharide CM1 lowers lipid and adipocyte differentiation by several pathways, and it has potential applications for hyperlipidemia prevention.

The Cordyceps militaris-Derived Polysaccharide CM1 Alleviates Atherosclerosis in LDLR(-/-) Mice by Improving Hyperlipidemia.

Atherosclerotic cardiovascular disease has a high mortality worldwide. Our lab previously purified a polysaccharide designated as CM1 with (1→4)-ß-D-Glcp and (1→2)-α-D-Manp glycosyls as the backbone. In this study, we investigated the anti-atherosclerosis effect of CM1 and the underlying mechanisms of action in a low-density lipoprotein receptor knockout (LDLR(-/-) mouse model. It was found that CM1 significantly decreased the formation of atherosclerotic plaques. Mechanistically, CM1 enhanced plasma level of apolipoprotein A-I and decreased the plasma levels of triglyceride, apolipoprotein B, and total cholesterol. In the absence of LDLR, CM1 elevated the expression of very low-density lipoprotein receptor for liver uptake of plasma apolipoprotein B-containing particles and reduced hepatic triglyceride synthesis by inhibiting sterol regulatory element binding protein 1c. CM1 improved lipids excretion by increasing the liver X receptor α/ATP-binding cassette G5 pathway in small intestine. CM1 reduced lipogenesis and lipolysis by inhibiting peroxisome proliferator-activated receptor γ and adipose triglyceride lipase in epididymal fat. Furthermore, CM1 improved lipid profile in C57BL/6J mice. Collectively, CM1 can modulate lipid metabolism by multiple pathways, contributing to reduced plasma lipid level and formation of atherosclerotic plaques in LDLR(-/-) mice. This molecule could be explored as a potential compound for prevention and treatment of hyperlipidemia and atherosclerosis.

Macrophage Plasticity and Atherosclerosis Therapy.

Atherosclerosis is a chronic disease starting with the entry of monocytes into the subendothelium and the subsequent differentiation into macrophages. Macrophages are the major immune cells in atherosclerotic plaques and are involved in the dynamic progression of atherosclerotic plaques. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition, and stability. The heterogenicity and plasticity of atherosclerotic macrophages have been a hotspot in recent years. Studies demonstrated that lipids, cytokines, chemokines, and other molecules in the atherosclerotic plaque microenvironment regulate macrophage phenotype, contributing to the switch of macrophages toward a pro- or anti-atherosclerosis state. Of note, M1/M2 classification is oversimplified and only represent two extreme states of macrophages. Moreover, M2 macrophages in atherosclerosis are not always protective. Understanding the phenotypic diversity and functions of macrophages can disclose their roles in atherosclerotic plaques. Given that lipid-lowering therapy cannot completely retard the progression of atherosclerosis, macrophages with high heterogeneity and plasticity raise the hope for atherosclerosis regression. This review will focus on the macrophage phenotypic diversity, its role in the progression of the dynamic atherosclerotic plaque, and finally discuss the possibility of treating atherosclerosis by targeting macrophage microenvironment.

The marine-derived furanone reduces intracellular lipid accumulation in vitro by targeting LXRα and PPARα.

Recent studies have demonstrated that commercially available lipid-lowering drugs cause various side effects; therefore, searching for anti-hyperlipidaemic compounds with lower toxicity is a research hotspot. This study was designed to investigate whether the marine-derived compound, 5-hydroxy-3-methoxy-5-methyl-4-butylfuran-2(5H)-one, has an anti-hyperlipidaemic activity, and the potential underlying mechanism in vitro. Results showed that the furanone had weaker cytotoxicity compared to positive control drugs. In RAW 264.7 cells, the furanone significantly lowered ox-LDL-induced lipid accumulation (~50%), and its triglyceride (TG)-lowering effect was greater than that of liver X receptor (LXR) agonist T0901317. In addition, it significantly elevated the protein levels of peroxisome proliferator-activated receptors (PPARα) and ATP-binding cassette (ABC) transporters, which could be partially inhibited by LXR antagonists, GSK2033 and SR9243. In HepG2 cells, it significantly decreased oleic acid-induced lipid accumulation, enhanced the protein levels of low-density lipoprotein receptor (LDLR), ABCG5, ABCG8 and PPARα, and reduced the expression of sterol regulatory element-binding protein 2 (~32%). PPARα antagonists, GW6471 and MK886, could significantly inhibit the furanone-induced lipid-lowering effect. Furthermore, the furanone showed a significantly lower activity on the activation of the expression of lipogenic genes compared to T0901317. Taken together, the furanone exhibited a weak cytotoxicity but had powerful TC- and TG-lowering effects most likely through targeting LXRα and PPARα, respectively. These findings indicate that the furanone has a potential application for the treatment of dyslipidaemia.

Ethanol extract of propolis protects macrophages from oxidized low density lipoprotein-induced apoptosis by inhibiting CD36 expression and endoplasmic reticulum stress-C/EBP homologous protein pathway.

BACKGROUND: Ethanol extract of propolis (EEP), rich in flavones, has been known for various biological activities including antioxidant, antiinflammatory and antibiotic activities. Our previous studies have shown that EEP protects endothelial cells from oxidized low-density lipoprotein (ox-LDL)-induced apoptosis and inhibits atherosclerotic lesion development. In this present study, we explored the protective effect of EEP on ox-LDL-induced cytotoxicity in macrophages and specifically the endoplasmic reticulum (ER) stress-C/EBP homologous protein (CHOP) pathway-mediated apoptosis. METHODS: EEP was prepared and the total flavonoids content of EEP was determined by the colorimetric method of Chinese Standard (GB/T 20574-2006). The effects of EEP on lipid accumulation, cytotoxicity and apoptosis in RAW264.7 cells induced by ox-LDL or tunicamycin (TM, an ER stress inducer) were assayed using oil red O staining, MTT assay, flow cytometric analysis and so on. Immunofluorescence, Western blot and real time-PCR analysis were then used to further investigate the molecular mechanisms by which EEP protects macrophages from ox-LDL-induced apoptosis. 4-phenylbutyric acid (PBA), an ER stress inhibitor, was used as a positive control. RESULTS: EEP (7.5, 15 and 30 mg/L) not only attenuated ox-LDL-induced lipid accumulation in RAW264.7 macrophages in a dose-dependent manner but also inhibited the decreased cell viability and the increased lactate dehydrogenase (LDH) leakage, caspase-3 activation and apoptosis induced by ox-LDL or tunicamycin (TM, a classical ER stress inducer), which were similar to 4-phenylbutyric acid (PBA, an inhibitor of ER stress) treatment. In addition, like PBA, EEP significantly suppressed the ox-LDL- or TM-induced activation of ER stress signaling pathway including the phosphorylation of double-stranded RNA-activated protein kinase-like ER kinase (PERK) and eukaryotic translation initiation factor 2α (eIF2α) as well as upregulation of glucose regulated protein 78 (GRP78) and the pro-apoptotic protein CHOP. Furthermore, EEP significantly suppressed ox-LDL intake by macrophages and the upregulation of CD36 induced by ox-LDL. CONCLUSION: These data indicate that EEP may protect macrophages from ox-LDL-induced apoptosis and the mechanism at least partially involves its ability to suppress the CD36-mediated ox-LDL intake and subsequent activation of ER stress-CHOP signalling pathway.

[Separation, purification and primary reverse cholesterol transport study of Cordyceps militaris polysaccharide].

The authors designed to separate, purify and determine the monosaccharide composition of the polysaccharide from Cordyceps militaris, and study its effect on reverse cholesterol transport in vivo by isotope tracing assay. Polysaccharides were separate and purify by ion exchange column Q-sepharose Fast Flow and size exclusion column Sephacryl S200HR; the molecular weight and monosaccharide composition of the polysaccharides were determined by high performance gel permeation chromatography and high performance liquid chromatography coming with pre-column derivation, respectively. Finally, three purified polysaccharides CMBW1, CMBW2 and CMYW1 were obtained, their total carbohydrate contents were 87%, 89%, 95%, respectively; their protein contents were 6.5%, 1.3%, 2.8%, respectively; their molecular weights were 772.1, 20.9, 13.2 kDa, respectively; CMBW1 was composed of mannose, glucosamine, rhamnose, glucuronic acid, glucose, galactose and arabinose with a molar ratio of 7.25: 0.17: 1.29: 0.23: 6.30: 11.08: 0.79; CMBW2 was composed of mannose, glucosamine, galactose and arabinose with a molar ratio of 2.40: 0.16: 2.92: 0.24; CMYW1 was composed of mannose, glucosamine, glucuronic acid and glucose with a molar ratio of 0.59: 0.57: 0.45: 25.61. Polysaccharide at 50 mg x kg(-1) could significantly improve the transport of 3H- cholesterol to blood and excretion from feces. All of the three purified polysaccharides CMBW1, CMBW2 and CMYW1 were heteropolysaccharide; and they could improve reverse cholesterol transport in vivo, the underlying mechanisms are being studied.

[Endoplasmic reticulum stress mediates oxidized low density lipoprotein-induced scavenger receptor A1 upregulation in macrophages].

The present study was to investigate whether endoplasmic reticulum stress (ERS) was involved in oxidized low density lipoprotein (ox-LDL)-induced scavenger receptor A1 (SR-A1) upregulation in macrophages. RAW264.7 cells were pretreated with 20 mmol/L of 4-phenylbutyric acid (PBA) for 30 min and then treated with ox-LDL (50 mg/L) for 12 h or stimulated with 2 mg/L tunicamycin (TM) or 2 µmol/L thapsigagin (TG) for 4 h. In addition, RAW264.7 cells were incubated with 0.5, 1 and 2 mg/L TM for 4 h or treated with 2 mg/L TM for 1, 2 and 4 h, respectively. The intracellular total cholesterol (TC) content was measured using a tissue/cell total cholesterol assay kit. The protein and mRNA expressions of SR-A1 and glucose-regulated protein 78 (GRP78) were analyzed by Western blot and real-time PCR, respectively. Dil-ox-LDL uptake was detected using a microplate reader. The results showed that ox-LDL-induced cholesterol accumulation in macrophages was attenuated by PBA, an ERS inhibitor. Ox-LDL caused significant SR-A1 upregulation with concomitant activation of ERS as assessed by upregulation of GRP78, whereas PBA significantly inhibited the ox-LDL-induced SR-A1 upregulation (P < 0.05) and slightly decreased GRP78 expression by 39.3% (P = 0.057). TM, an ERS inducer, upregulated SR-A1 protein expression and ox-LDL uptake in dose- and time-dependent manner, but had no significant effect on SR-A1 mRNA level. However, the TM- or TG-induced SR-A1 upregulation and ox-LDL uptake were significantly mitigated by PBA. These data indicate that ERS plays a critical role in ox-LDL-induced SR-A1 upregulation, which in turn enhances the foam cell formation by uptaking more ox-LDL.