Effect of leech on lipid metabolism and liver in hyperlipidemia rats / 中国中药杂志

To explore the effect of leech on lipid metabolism and liver function in hyperlipidemia rats and the possible mechanism, biochemical analyzer was used to examine the regulation of leech on levels of serum triglycerides(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C). The levels of ALT and AST in serum were detected by ELISA. The proteins expression of ACAT-2, Fas and HMGCR in liver tissue was detected by Western blot. The weight of body and liver were weighed, and liver index was calculated. Oil red O staining was used to observe the lipid accumulation in liver tissue of rats by light Microscope. The results showed that leech could decrease the levels of TC, LDL-C obviously, and increase HDL-C, decrease the levels of ALT, AST and the liver index, down-regulate the proteins expression of ACAT-2, Fas and HMGCR. And oil red O staining indicated that the lipid accumulation was less in the liver tissue of the rats intervented by leech. These data indicated that leech may affect the expression of ACAT-2, Fas and HMGCR in liver tissue to reduce the synthesis of cholesterol and fatty acid, and promote the cholesterol transforming, then regulate lipid metabolism to decrease the levels of serum lipid, and reduce lipid accumulation in liver tissue and ease liver injury of rats, then slowing down the process of nonalcoholic fatty liver disease(NAFLD) in hyperlipidemia rats.

Corn silk extract improves cholesterol metabolism in C57BL/6J mouse fed high-fat diets

BACKGROUND/OBJECTIVES: Corn silk (CS) extract contains large amounts of maysin, which is a major flavonoid in CS. However, studies regarding the effect of CS extract on cholesterol metabolism is limited. Therefore, the purpose of this study was to determine the effect of CS extract on cholesterol metabolism in C57BL/6J mouse fed high-fat diets. MATERIALS/METHODS: Normal-fat group fed 7% fat diet, high-fat (HF) group fed 25% fat diet, and high-fat with corn silk (HFCS) group were orally administered CS extract (100 mg/kg body weight) daily. Serum and hepatic levels of total lipids, triglycerides, and total cholesterol as well as serum free fatty acid, glucose, and insulin levels were determined. The mRNA expression levels of acyl-CoA: cholesterol acyltransferase (ACAT), cholesterol 7-alpha hydroxylase (CYP7A1), farnesoid X receptor (FXR), lecithin cholesterol acyltransferase (LCAT), low-density lipoprotein receptor, 3-hyroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), adiponectin, leptin, and tumor necrosis factor α were determined. RESULTS: Oral administration of CS extract with HF improved serum glucose and insulin levels as well as attenuated HF-induced fatty liver. CS extracts significantly elevated mRNA expression levels of adipocytokines and reduced mRNA expression levels of HMG-CoA reductase, ACAT, and FXR. The mRNA expression levels of CYP7A1 and LCAT between the HF group and HFCS group were not statistically different. CONCLUSIONS: CS extract supplementation with a high-fat diet improves levels of adipocytokine secretion and glucose homeostasis. CS extract is also effective in decreasing the regulatory pool of hepatic cholesterol, in line with decreased blood and hepatic levels of cholesterol though modulation of mRNA expression levels of HMG-CoA reductase, ACAT, and FXR.

High-Density Lipoprotein, Lecithin: Cholesterol Acyltransferase, and Atherosclerosis

Epidemiological data clearly show the existence of a strong inverse correlation between plasma high-density lipoprotein cholesterol (HDL-C) concentrations and the incidence of coronary heart disease. This relation is explained by a number of atheroprotective properties of HDL, first of all the ability to promote macrophage cholesterol transport. HDL are highly heterogeneous and are continuously remodeled in plasma thanks to the action of a number of proteins and enzymes. Among them, lecithin:cholesterol acyltransferase (LCAT) plays a crucial role, being the only enzyme able to esterify cholesterol within lipoproteins. LCAT is synthetized by the liver and it has been thought to play a major role in reverse cholesterol transport and in atheroprotection. However, data from animal studies, as well as human studies, have shown contradictory results. Increased LCAT concentrations are associated with increased HDL-C levels but not necessarily with atheroprotection. On the other side, decreased LCAT concentration and activity are associated with decreased HDL-C levels but not with increased atherosclerosis. These contradictory results confirm that HDL-C levels per se do not represent the functionality of the HDL system.

The effects of black garlic (Allium satvium) extracts on lipid metabolism in rats fed a high fat diet

BACKGROUD/OBEJECTIVES: The mechanism of how black garlic effects lipid metabolism remains unsolved. Therefore, the objectives of this study were to determine the effects of black garlic on lipid profiles and the expression of related genes in rats fed a high fat diet. MATERIALS/METHODS: Thirty-two male Sqrague-Dawley rats aged 4 weeks were randomly divided into four groups (n=8) and fed the following diets for 5 weeks: normal food diet, (NF); a high-fat diet (HF); and a high-fat diet + 0.5% or 1.5% black garlic extract (HFBG0.5 or HFBG1.5). Body weights and blood biochemical parameters, including lipid profiles, and expressions of genes related to lipid metabolism were determined. RESULTS: Significant differences were observed in the final weights between the HFBG1.5 and HF groups. All blood biochemical parameters measured in the HFBG1.5 group showed significantly lower values than those in the HF group. Significant improvements of the plasama lipid profiles as well as fecal excretions of total lipids and triglyceride (TG) were also observed in the HFBG1.5 group, when compared to the HF diet group. There were significant differences in the levels of mRNA of sterol regulatory element binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PDH) in the HFBG1.5 group compared to the HF group. In addition, the hepatic expression of (HMG-CoA) reductase and Acyl-CoA cholesterol acyltransferase (ACAT) mRNA was also significantly lower than the HF group. CONCLUSIONS: Consumption of black garlic extract lowers SREBP-1C mRNA expression, which causes downregulation of lipid and cholestrol metahbolism. As a result, the blood levels of total lipids, TG, and cholesterol were decreased.

Lecithin: Cholesterol Acyltransferase and Na(+)-K(+)-ATPase Activity in Patients with Breast Cancer / 한국유방암학회지

PURPOSE: The aim of this study was to determine whether plasma lecithin:cholesterol acyltransferase (pLCAT) and erythrocyte membrane Na(+)-K(+)-ATPase ase (emNaKATPs) activity have a correlation in breast cancer. This study compared these parameters at time points before and after treatment with radiotherapy. METHODS: The levels of pLCAT and emNaKATPs were assessed in 30 patients with breast carcinoma and 20 control subjects. While emNaKATPs was measured with spectrophotometric method, pLCAT levels was measured using a specific enzyme-linked immunosorbent assay. RESULTS: pLCAT levels, both before and after radiotherapy, were found to be decreased in breast cancer patients than in the controls groups (p0.05). CONCLUSION: The results of the present study demonstrated that decreased pLCAT and emNaKATPs activity levels in breast cancer patients after/before RT than control group. In addition, decreased emNaKATPs activity in breast cancer patients receiving radiotherapy may be due to decreased pLCAT concentrations and RT beam. In our opinion, altered activities of pLCAT and emNaKATPs are linked to the treatment effect of radiotherapy. These data may clarify the development of cell membrane dysfunction and lipid metabolism in breast cancer patients receiving radiotherapy.

The effect of fucoxanthin rich power on the lipid metabolism in rats with a high fat diet

This study determined the effects of fucoxanthin on gene expressions related to lipid metabolism in rats with a high-fat diet. Rats were fed with normal fat diet (NF, 7% fat) group, high fat diet group (HF, 20% fat), and high fat with 0.2% fucoxanthin diet group (HF+Fxn) for 4 weeks. Body weight changes and lipid profiles in plasma, liver, and feces were determined. The mRNA expressions of transcriptional factors such as sterol regulatory element binding protein (SREBP)-1c, Carnitine palmitoyltransferase-1 (CPT1), Cholesterol 7alpha-hydroxylase1 (CYP7A1) as well as mRNA expression of several lipogenic enzymes were determined. Fucoxanthin supplements significantly increased plasma high density lipoprotein (HDL) concentration (P < 0.05). The hepatic total lipids, total cholesterols, and triglycerides were significantly decreased while the fecal excretions of total lipids, cholesterol, and triglycerides were significantly increased in HF+Fxn group (P < 0.05). The mRNA expression of hepatic Acetyl-CoA carboxylase (ACC), Fatty acid synthase (FAS), and Glucose-6-phosphate dehydrogenase (G6PDH) as well as SREBP-1C were significantly lower in HF+Fxn group compared to the HF group (P < 0.05). The hepatic mRNA expression of Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and Acyl-CoA cholesterol acyltransferase (ACAT) were significantly low while lecithin-cholesterol acyltransferase (LCAT) was significantly high in the HF+Fxn group (P < 0.05). There was significant increase in mRNA expression of CPT1 and CYP7A1 in the HF+Fxn group, compared to the HF group (P < 0.05). In conclusion, consumption of fucoxanthin is thought to be effective in improving lipid and cholesterol metabolism in rats with a high fat diet.

Lipids-induced apoptosis is aggravated by acyl-coenzyme A: cholesterol acyltransferase inhibitor / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the role of acyl-coenzyme A: cholesterol acyltransferase inhibitor (ACATI) in apoptosis induced by lipids and whether lipids-induced apoptosis is accompanied by increase of free cholesterol in endoplasmic reticulum (ER), in order to further understand the mechanism of lipids-induced apoptosis in advanced atherosclerosis.</p><p><b>METHODS</b>Human vascular smooth muscle cells (VSMCs) and phorbol 12-myristate 13-acetate (PMA) differentiated THP-1 macrophages were used. Tritiated thymidine incorporation was applied to detect cell proliferation. Cytotoxicity was assessed by lactate dehydrogenase (LDH) release. 4',6-diamidino-2-phenylindole (DAPI) staining, caspase-3, -7 assay, and Annexin-V/propidium iodide (PI) staining were used to detect apoptosis. High performance liquid chromatography was used in intracellular free cholesterol and cholesterol ester assay. ER free cholesterol was quantified.</p><p><b>RESULTS</b>Different lipids had different effects on proliferation and cytotoxicity of VSMCs. 25-hydroxycholesterol (25OHC) had biphasic effects on the proliferation of VSMCs. At low concentration, it stimulated cell proliferation, but turned to proliferation inhibition as concentration reached 15 mug/mL. 25OHC and acetylated low density lipoprotein (AcLDL) could respectively induce apoptosis in human VSMCs and PMA differentiated THP-1 macrophages, which was aggravated by ACATI, accompanied by increase of intracellular free cholesterol content. There was also an increase of cholesterol content in ER with AcLDL-induced apoptosis in THP-1 macrophages.</p><p><b>CONCLUSIONS</b>Lipids could induce apoptosis, accompanied by increase of intracellular free cholesterol content, which could be augmented by ACATI, suggesting that insults resulting in ER free cholesterol rise might be the initiator of apoptosis.</p>

Regulation of acyl-coenzyme A: cholesterol acyltransferase 2 expression by saturated fatty acids / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs).</p><p><b>METHODS</b>Palmitic acid (PA), the most abundant saturated fatty acid in plasma, and oleic acid (OA), a widely distributed unsaturated fatty acid, were used to treat hepatic cells HepG2, HuH7, and mouse primary hepatocytes. In addition, PA at different concentrations and PA treatment at different durations were applied in HepG2 cells. In in vivo experiment, three-month male C57/BL6 mice were fed with control diet and SFA diet containing hydrogenated coconut oil rich of SFAs. The mRNA level of ACAT2 in those hepatic cells and the mouse livers was detected with real-time polymerase chain reaction (PCR).</p><p><b>RESULTS</b>In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression (Pü0.01), whereas treatment with OA showed no significant effect. That effect of PA was noticed gradually rising along with the increase of PA concentration and the extension of PA treatment duration (both Pü0.05). SFA diet feeding in mice resulted in a short-term and transient increase of ACAT2 expression in vivo, with a peak level appearing in the mice fed with SFA diet for two days (Pü0.05).</p><p><b>CONCLUSION</b>SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.</p>

Cholesterol oxides inhibit cholesterol esterification by lecithin: cholesterol acyl transferase / Óxidos de colesterol por inibir a esterificação do colesterol lecitina: colesterol acil transferase

Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7β-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3β,5α,6β-triol,5,6β-epoxycholesterol, 5,6α-epoxycholesterol and 7α-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43) and the transfer of esters of cholesterol oxides from high density lipoprotein (HDL) to low density lipoproteins (LDL) and very low density lipoproteins (VLDL) by cholesteryl ester transfer protein (CETP) was investigated. HDL enriched with increasing concentrations of cholesterol oxides was incubated with fresh plasma as source of LCAT. Cholesterol and cholesterol oxides esterification was followed by measuring the consumption of respective free sterol and oxysterols. Measurements of cholesterol and cholesterol oxides were done by gas-chromatography. 14C-cholesterol oxides were incorporated into HDL2 and HDL3 subfractions and then incubated with fresh plasma containing LCAT and CETP. The transfer of cholesterol oxide esters was followed by measuring the 14C-cholesterol oxide-derived esters transferred to LDL and VLDL. All the cholesterol oxides studied were esterified by LCAT after incorporation into HDL particles, competing with cholesterol by LCAT. Cholesterol esterification by LCAT was inversely related to the cholesterol oxide concentration. The esterification of 14C-cholesterol oxides was higher in HDL3 and the transfer of the derived esters was greater from HDL2 to LDL and VLDL. The results suggest that cholesterol esterification by LCAT is inhibited in cholesterol oxide-enriched HDL particles. Moreover, the cholesterol oxides-derived esters are efficiently transferred to LDL and VLDL. Therefore, we suggest that cholesterol oxides may exert part of their atherogenic effect by inhibiting cholesterol esterification...

Os óxidos de colesterol são aterogênicos e podem afetar a atividade de diversas enzimas importantes para o metabolismo lipídico. Este estudo investigou o efeito dos óxidos 7β-hidroxicolesterol, 7-cetocolesterol, 25-hidroxicolesterol, colestan-3β,5α,6β-triol, 5,6β-epoxicolesterol, 5,6α-epoxicolesterol e 7α-hidroxicolesterol na esterificação do colesterol por ação da lecitina colesterol aciltransferase (LCAT, EC 2.3.1.43) e a posterior transferência dos óxidos esterificados da lipoproteína de alta densidade (HDL) para as lipoproteínas de baixa densidade (LDL) e muito baixa densidade (VLDL) mediada pela proteína de transporte de éster de colesterol (CETP). Para atingir os objetivos, HDL enriquecida com concentrações crescentes de óxidos de colesterol foi incubada com plasma fresco pobre em lipoproteínas, como fonte de LCAT; posteriormente a esterificação do colesterol e dos óxidos de colesterol foi medida pelo consumo do colesterol livre e dos óxidos livres presentes na HDL. As determinações de colesterol e dos óxidos de colesterol foram realizadas por cromatografia gasosa. 14C-óxidos de colesterol foram incorporados nas subfrações HDL2 e HDL3 e posteriormente incubados com plasma fresco, contendo LCAT e CETP. A transferência dos ésteres de óxidos de colesterol foi medida e quantificada pela presença desses ésteres na LDL e VLDL. Todos os óxidos de colesterol estudados foram esterificados pela LCAT após incorporação nas partículas de HDL e competiram com a esterificação do colesterol nativo. A esterificação do colesterol pela LCAT foi inversamente relacionada à concentração de óxidos de colesterol. A esterificação dos óxidos de colesterol foi maior na HDL3 e a transferência desses ésteres foi maior a partir da HDL2 para a LDL e VLDL. Estes resultados indicam que a esterificação do colesterol pela LCAT é inibida nas partículas de HDL enriquecidas com óxidos de colesterol e que os ésteres de óxidos de colesterol...

Chlamydia pneumoniae induces THP-1-derived foam cell formation by up-regulating the expression of acyl-coenzyme A: cholesterol acyltransferase 1 / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the expression changes of acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1) on Chlamydia pneumoniae (C.pn) induced foam cell formation.</p><p><b>METHODS</b>Human monocytic cell line (THP-1) was induced into macrophages by 160 nmol/L phorbol myristate acetate (PMA) for 48 h, and were randomly allocated into four groups: negative control group (50 microg/ml LDL for 48 h); positive control group (50 microg/ml ox-LDL for 48 h); C.pn infection group (50 microg/ml LDL plus 1 x 10(5), 4 x 10(5), 5 x 10(5) and 1 x 10(6) IFU C.pn for 48 h or 1 x 10(6) IFU C.pn for 0, 24, 48 and 72 h); ACAT inhibitor 58-035 plus C.pn infection group (1, 5, 10 microg/ml ACAT inhibitor 58-035 pretreatment for 1 h, 50 microg/ml LDL and 1 x 10(6) IFU C.pn for 48 h). The mRNA and protein expressions of ACAT1 were determined by RT-PCR and Western blot, respectively. Lipid droplets in cytoplasm were observed by oil red O staining. The contents of intracellular cholesteryl esters were detected by enzyme-fluorescence.</p><p><b>RESULTS</b>The mRNA and protein expressions of ACAT1 were significantly up-regulated in positive control cells compared those in negative control cells and further upregulated by C.pn infection in a time-dependent and concentration-dependent manner (all P < 0.05). There were significantly increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol in positive control cells as compared with negative control cells and these were further aggravated by C.pn (at the concentrations of 5 x 10(5) and 1 x 10(6) IFU for 48 h) and C.pn infection induced increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol could be significantly attenuated by ACAT inhibitor 58-035 (all P < 0.05).</p><p><b>CONCLUSION</b>Chlamydia pneumoniae induces THP-1-derived foam cell formation by up-regulating the expression of ACAT1.</p>

Effect of Young Barley Leaf on Lipid Contents and Hepatic Lipid-Regulating Enzyme Activities in Mice Fed High-Fat Diet

This study was conducted to investigate the effects of powdered young barley leaf and its water extract on body weight and lipid metabolism in high-fat fed mice. Male mice were divided into normal group, high-fat (HF) group, highfat group supplemented with powdered young barley leaf (HF-YBL) and high-fat group supplemented with water extract of the powdered young barley leaf (HF-WYBL). The powdered young barley leaf or its water extract was added to a standard diet based on 1% dried young barley leaf (1 g YBL/100 diet and 0.28 g WYBL/100 g diet) for 8 weeks. Supplementation of YBL and WYBL significantly reduced body weight and epididymal adipose tissue weight in highfat fed mice. Food intake and daily energy intake were significantly lower in the YBL group than in the HF group. After 8 weeks, plasma triglyceride and cholesterol concentrations were significantly higher in the HF group than in the Normal group; however, both YBL and WYBL significantly lowered those of the high-fat fed mice. The ratio of HDL-cholesterol/ total cholesterol of the YBL and WYBL groups were significantly elevated compared to that of HF group. Both YBL and WYBL significantly increased fecal excretion of triglyceride in high-fat fed mice, whereas they did not affect fecal cholesterol concentration. The triglyceride levels of liver, adipose tissue and heart were significantly lower in the YBL and WYBL groups than in the HF group. Supplementation of WYBL also lowered the kidney triglyceride and heart cholesterol concentrations compared to those of HF group. Hepatic lipid regulating enzyme activities, fatty acid synthase, HMG-CoA reductase and acyl-coenzyme A: cholesterol acyltransferase, were significantly lower in the YBL and WYBL groups than in the HF group. Accordingly, these results suggest that YBL and WYBL improve plasma and organ lipid levels partly by increasing fecal lipid excretion and inhibiting fatty acid and cholesterol biosynthesis in the liver.

Analysis of acyl-coenzyme A: cholesterol acyltransferase 1 polymorphism in patients with endogenous hypertriglyceridemia in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the polymorphism of acyl-coenzyme A: cholesterol acyltransferase 1(ACAT1) gene and its relationship with endogenous hypertriglyceridemia (HTG) in Chinese population.</p><p><b>METHODS</b>A total of three hundred and seventy-two subjects (105 endogenous hypertriglyceridemics and 267 healthy controls) from a population of Chinese Han nationality in Chengdu area were studied using PCR-restriction fragment length polymorphism (RFLP).</p><p><b>RESULTS</b>The frequency of C allele in normal Chinese at rs1044925 locus was 0.137, which was lower than that reported in the population of central and Southern Europe (0.354) (P< 0.05). The frequency C allele was 0.153 in HTG group. No significant difference between normal control and HTG group. In control group, subjects with genotype AA had a higher serum mean concentrations of low density lipoprotein-cholesterol (LDL-C) and non-high density lipoprotein-cholesterol(nHDL-C) when compared with those of C allele carriers (AC and CC genotype carriers), respectively [(3.25+/- 0.68) mmol/L vs (3.03+/- 0.87) mmol/L, P< 0.05; (3.80+/- 0.71) mmol/L vs (3.23+/- 0.82) mmol/L, P< 0.05]. In HTG group, subjects with genotype AA had a higher high density lipoprotein-cholesterol (HDL-C) level compared with those of C allele carriers [(1.00+/- 0.28) mmol/L vs (0.87+/- 0.17) mmol/L, P< 0.05].</p><p><b>CONCLUSION</b>These results suggest that rs1044925 polymorphism in ACAT1 gene is not only associated with serum LDL-C and nHDLC levels in healthy Chinese subjects in Chengdu area, but also with HDL-C level in subjects with endogenous hypertriglyceridemia in this population.</p>

Construction and identification of recombinant firefly luciferase report vector containing human acyl coenzyme a: cholesterol acyltransferase 1 gene P7 promoter / 生物医学工程学杂志

The DNA segment of the human acyl coenzyme A: cholesterol acyltransferasel (ACAT1) gene P7 promoter was amplified by PCR from human monocytic leukemia cell line (THP-1) and cloned to TA vector, then the positive clone was confirmed by restriction enzymes and sequencing. The targeted segment was subcloned to Firefly luciferase report vector pGL3-Enhancer. The recombinant plasmid pGL3E-P7 was transfected transiently into THP-1, then the expression of luciferase could be detected in THP-1 by pGL3E-P7 transfection. We successfully constructed luciferase reporter vector containing P7 promoter of the human ACAT1 gene, and established a new means to study the transcriptional regulation mechanisms of ACAT1 during atherosclerosis.

NADPH oxidase activity does not affect cellular cholesterol loading in vascular smooth muscle cells / 生理学报

Reactive oxygen species generated by NADPH oxidase enhance aortic vascular smooth muscle cell proliferation and migration which play an important role in the pathophysiology of atherosclerosis. We investigated the role of NADPH oxidase in the cellular cholesterol metabolism in vascular smooth muscle cells using p47phox-deficient cells. Wild-type and p47phox knockout vascular smooth muscle cells were loaded with cholesterol for 72 h by using 10 mg/L cholesterol:methyl-beta-cyclodextrin complexes and then incubated with or without 0.3 mg/L thrombin for 10 min. Foam cell formation was determined by accumulation of intracellular cholesterol, oil Red O-stained lipid droplets. After cholesterol loading, cellular lipid droplets raised sharply, cellular cholesterol increased from (31.4+/-2.0) to (61.0+/-2.1) mg/g protein (P<0.05) in wild-type cells, and from (29.8+/-2.5) to (51.3+/-3.1) mg/g protein (P<0.05) in p47phox deficient cells, but the difference between the two cell types was not significant. Immunostaining showed decreased levels of smooth muscle alpha-actin and increased levels of macrophage marker Mac-2 in both wild-type and p47phox deficient vascular smooth muscle cells. One of the macrophage-related inflammation genes, monocyte chemoattractant protein-1 (MCP-1) expression did not change in both two cell types detected by immunostaining. Although additional incubating with thrombin, another macrophage-related inflammation gene, vascular cell adhesion molecule-1 (VCAM-1) expression was similar in all groups analyzed by real-time RT-PCR. However, the expression of ATP-binding cassette transporter A1 (ABCA1), acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1), the key proteins in cellular cholesterol metabolism, were similarly increased (P<0.05) in both two cell types as determined by quantitative real-time RT-PCR and Western blot, and it was not related to the state of oxidative stress. Interestingly, the expression of adipophilin, the lipid droplet related protein, had the similar results with ABCA1 and ACAT1, but, in wild-type cells, its expression also increased merely incubating with thrombin as determined by quantitative real-time RT-PCR. Together, these results suggest that p47phox-dependent NADPH oxidase is not involved in transdifferentitation of vascular smooth muscle cells into macrophage-like state after cholesterol loading. Deleting p47phox gene does not affect the cellular cholesterol metabolism in vascular smooth muscle cells.

Inhibition of acyl-coenzyme A:cholesterol acyltransferase stimulates cholesterol efflux from macrophages and stimulates farnesoid X receptor in hepatocytes

We investigated the mechanism of spontaneous cholesterol efflux induced by acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibition, and how an alteration of cholesterol metabolism in macrophages impacts on that in HepG2 cells. Oleic acid anilide (OAA), a known ACAT inhibitor reduced lipid storage substantially by promotion of cholesterol catabolism and repression of cholesteryl ester accumulation without further increase of cytotoxicity in acetylated low-density lipoprotein-loaded THP-1 macrophages. Analysis of expressed mRNA and protein revealed that cholesterol 7alpha-hydroxylase (CYP7A1), oxysterol 7alpha- hydroxylase (CYP7B1), and cholesterol 27-hydroxylase (CYP27) were highly induced by ACAT inhibition. The presence of a functional cytochrome P450 pathway was confirmed by quantification of the biliary cholesterol mass in cell monolayers and extracelluar medium. Notably, massively secreted biliary cholesterol from macrophages suppressed the expression of CYP7 proteins in a farnesoid X receptor (FXR)-dependent manner in HepG2 cells. The findings reported here provide new insight into mechanisms of spontaneous cholesterol efflux, and suggest that ACAT inhibition may stimulate cholesterol-catabolic (cytochrome P450) pathway in lesion-macrophages, in contrast, suppress it in hepatocyte via FXR induced by biliary cholesterol (BC).

Effects of leptin on expression of acyl-coenzymea: cholesterol acyltransferases-1 in cultured human monocyte-macrophages / 华中科技大学学报（医学）（英德文版）

To investigate the effects of leptin on expression of acyl-coenzymeA: cholesterol acyl-transferases-1 (ACAT-1) in monocyte-macrophage differentiation, human monocytic cells (THP-1) were cultured in RPMI 1640 and made to differentiate into macrophages under the incubation with phorbol myristate acetate (PMA) for 48 h. The cells were divided into 4 groups according to different intervention factors as follows: MCs cultured in RPM11640 medium with 10% FBS for 48 h served as MC group (control group), MCs cultured in medium with serum-free RPM11640 containing 5% BSA, 100 nmol/L PMA for 48 h as MP group, MCs cultured in RPMI1640 medium with 10% FBS, 10 micromol/ml leptin for 48 h as leptin-MC group, and MCs cultured in medium with serum-free RPMI1640 containing 5% BSA. 100 nmol/L PMA, and 10 micromol/ml leptin for 48 h as leptin-MP group. Immunocytochemistry, reverse transcription polymerase chain reaction (RT-PCR) and Western blot were performed, respectively, to observe the effects of leptin on expression of ACAT-1 in the monocyte-macrophage differentiation. Our results showed that expression of ACAT-1 protein and mRNA in MP-group is two times that in MC-group (P<0.05), and the expression of ACAT-1 protein and mRNA increased by up to 4 folds in leptin-MP group-as compared with that of MC group (P<0.01). Thus, our results support the idea that expression of ACAT-1 increases more in cultured human macrophages than in monocytes, and leptin can significantly promote ACAT-1 expression. It was concluded that high expression of ACAT-1 may accelerate the development of human atherogenesis, and leptin might participate in atherogenesis by increasing expression of ACAT-1.

Quantitative structure-activity relationship of 4,5-diphenyl-2-(substituted thio)-1H-imidazoles as the inhibitors of acyl CoA: cholesterol acyltransferase.

A quantitative structure-activity relationship (QSAR) analysis of 4,5-diphenyl-2-(substituted thio)-1H-imidazoles as the potential inhibitors of acyl CoA: cholesterol acyltransferase is presented with a view to reflect upon the parametric requirement of various substitutions. For this purpose the van der Waals volume, Vw which is the measure of molecular bulk/size of substituents present at R1- and R2-positions has emerged as the befitting correlative parameter. A number of correlations obtained amongst different subclasses of the title compounds have helped in ascertaining the relative importance of X-substituents and the role of Vw(R1) and Vw(R2). Finally, a significant correlation between the sum of van der Waals volume of R1- and R2-substituents, sigma Vw and biological activities of the entire series was also derived. From the resulting parabolic QSAR equation, an optimum molecular bulk of 1.846 x 10(2) A3 leading to the highest potent compound of the series, specially among those congeners which have X = -NH-, was predicted. This finding has, therefore, hinted at the existence of a cavity, capable of accommodating the maximum steric bulk, on to the receptor.

Everted intestinal sacs as an in-vitro model for testing efficacy of new hypocholesterolemic agents

In the current study we investigated the effects of five new Acyl-CoA:Cholesterol acyltransferase enzyme [ACAT] inhibitors on the extent of absorption of tritiated cholesterol using the everted intestinal sacs obtained from naive or cholesterol-fed rats. The extent of absorption of cholesterol was determined in the presence of the five analogs. Everted intestinal segments from male Sprague-Dawley rats filled with serosal incubation medium were added to a mucosal solution incubation medium containing 750. [micro]M [3] H-cholesterol. The compounds were added to the mucosal solution at a concentration of 15 mM. Samples were taken from serosal fluid over a period of two hours and monitored for increases in radioactivity concentrations [[3] H-cholesterol] inside the everted sac. Comparisons were made between incubations with and without the drugs in order to assess inhibitory effects of the compounds on cholesterol absorption. All calculations were based on the extent of cholesterol accumulation at the end of two hours. Absorption of cholesterol increased considerably in the cholesterol-fed rats, relative to naive rats. This effect is thought to be due to increased ACAT enzyme activity following cholesterol pretreatment. In naive rats, the addition of the different analogs [I through V] decreased the absorption of cholesterol by 58, 49, 22, 0, and 0%, respectively. Decreases of 97, 67, 58,44 and 54% were obtained for the same compounds in cholesterol-fed rats. The parent compounds were not detected in the serosal fluids using HPLC assay, indicating poor absorption of the compounds through the intestinal wall. Significant concentrations of the drugs were detected within the intestinal tissues. The everted gut technique provided a good model for assessing the efficacy of the hypolipidemic agents based on inhibition of cholesterol absorption at a single incubation concentration

Effect of experimental Schistosomiasis on 14C-4-cholesterol esterification by mouse liver homogenate

The effect of experimental schistosomiasis mansoni on cholesterol esterification by mouse liver homogenate was studied using 14C-4-cholesterol. The reaction was carried out in 0.85 ml containing 10 nCi labelled cholesterol (I64 nmol as an albumin-stabilized emulsion) with 30 mg tissue homogenate in 176 mM sodium phosphate buffer, pH 7.1, containing 59 micronM oleic acid, 0.3 mM CoASH and 8.8 mM ATP. In experiments with liver from infected mice(N = 22), the percentage of cholesterol esterification was 6.9 + or - 0.7%/h. This rate was 52% less than that observed in normal mice (14.4 + or - 0.6%/h, N = 21). The decrease may be due to the existence of inhibitors of the cholesterol esterifying in the infected liver, increased hydrolysis of cholesteryl esters or a decrease in the synthesis of the enzyme acyl CoA:cholesterol acyl transferase by the infected liver