ZBM30 suppresses atherosclerosis through up-regulating ATP-binding cassette A1 and G1

Atherosclerosis is the most common cause of cardiovascular diseases, such as myocardial infarction and stroke. The aim of this study was to investigate the effects of a novel compound ZBM30 on atherosclerosis in ApoE- deficient mice and its associated mechanism. ApoE-deficient mice （6 weeks old）, fed an atherogenic high-fat and high cholesterol diet for 8 weeks, were divided into three groups. Two groups were orally administrated ZBM30 （10, 30 nag ~ kg-1） daily for 12 weeks, while the control group was administered saline. Atherosclerotic lesions with en face aortas were evaluated by Sudan IV staining, and lesion areas in aortic sinuses were evaluated by oil red O staining. Necrotic core areas and fibrous cap areas in the lesion were evaluated by henaatoxylin and eosin （HE） staining and Masson＇ s trichronae staining in the aorta sinuses. The effects of ZBM30 on cholesterol accumulation in naacrophages and cholesterol transporters： ATP binding cassette A1 （ABCA1） and ATP binding cassette G1 （AB- CG1） were evaluated by oil red O assay, 3H-cholesterol efflux assay, Western blot, and real-time PCR on macro- phage cell lines： Raw 264.7 and THP-1. Inanauno-fluoresces was used to determine the ABCA1 expression in naac- rophage in aorta sinuses. Luciferase reporters of wild type and mutant types of ABCA1 promoter were constructed to determine the regulatory domain of ZBM30 on ABCA1 promoter. Results showed that, compared with the control group, en face lesions in ZBM30 group （ 10, 30 mg · kg^-1 ） were reduced 54.96 ± 10.06% and 71.50 ± 15.37% respectively, and aorta sinus lesions were reduced 41.85 ± 11.21% and 82.23 ± 8.25% respectively. Necrotic core areas in the ZBM30 group were markedly reduced and fibrous cap areas were not changed. Oil red O staining and 3 H-cholesterol efflux assays on Raw 264.7 cell line revealed that ZBM30 significantly attenuated the cholesterol accumulation in naacrophages by enhancing apolipoprotein AI and HDL mediated cholesterol efflux. Furthermore, ZBM30 induced the protein and naRNA expression of cholesterol transporters such as ABCA1 and ABCG1. Inanauno- fluoresces experiment revealed that ZBM30 induced the ABCA1 expression in naacrophage in the lesion, which is consistent with the results in vitro. Luciferase reporter assay revealed that ZBM30 exerted its effect on ABCA1 via liver X receptor （LXR） binding domain. In conclusion, ZBM30 suppresses atherosclerosis through up-regulating cholesterol efflux via ABCA1 and ABCG1 transporters in ApoE-deficient mice.

Inhibiting NF-κB increases cholesterol efflux from THP-1 derived-foam cells treated with AngⅡ via up-regulating the expression of ATP-binding cassette transporter A1

Objective： To study the role of nuclear factor-kappa B（NF- κB） in cholesterol efflux from THP-1 derived-foam cells treated with Angiotensin Ⅱ（Ang Ⅱ ）. Methods：Cultured THP-1 derived-foam cells were treated with Ang Ⅱ or preincubated with tosyl-phenylalanine chloromethyl-ketone（TPCK） NF- κB inhibitor. The levels of activated NF- κB in the cells were examined by sandwich ELISA, Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol effiux was detected by scintillation counting technique. ABCA1 mRNA and protein were quantified by RT-PCR and Western blotting. Results：Addition of TPCK to the cells before Ang Ⅱ stimulation attenuated the response of NF- κB p65 nuclear translocation induced by Ang Ⅱ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol efflux by 24.1%（P〈 0.05） and 41.1%（P〈 0.05） respectively, when compared with Ang Ⅱ group. In accordance, the ABCA1 mRNA and protein were increased by 30% and 19%（P 〈 0.05） respectively, when compared with Ang Ⅱ group. Conclusion：Ang Ⅱ can downregulate ABCA1 in THP-1 derived-foam cells via NF- K B, which leads to less cholesterol effiux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.

TLR4通过下调ABCA1表达促进平滑肌源性泡沫细胞形成

目的探讨Toll样受体4(Toll-like receptor 4,TLR4)促进平滑肌源性泡沫细胞的形成是否与三磷酸腺苷-结合盒转运子A1(ATP-binding cassette transporter,ABCA1)表达异常相关。方法组织贴块法培养原代血管平滑肌细胞(vascular smooth muscle cells,VSMCs);细胞分为野生型(Wild type)空白对照组、Wild type氧化低密度脂蛋白(oxLDL)组、TLR4敲除(TLR4-/-)空白对照组和TLR4-/-oxLDL组;油红O染色观察VSMCs内脂质聚集,并用异丙醇萃取油红O测定光密度值;RT-qPCR、Western blot检测VSMCs中TLR4、ABCA1、IL-1β及TNF-αmRNA和蛋白表达水平;细胞免疫荧光染色鉴定原代VSMCs及观察核转录因子-kappa B(NF-κB)核转位。结果①Wild type oxLDL组中见细胞内大量脂滴形成,油红O光密度值为Wild type空白对照组的2.3倍(P<0.01);TLR4-/-oxLDL组中只见少许脂质沉积于细胞内,油红O光密度值与TLR4-/-空白对照组相比无明显变化(P>0.05)。②Wild type oxLDL组ABCA1 mRNA及蛋白表达水平较Wild type空白对照组分别下降61%(P<0.05),44%(P<0.01);TLR4-/-oxLDL组ABCA1 mRNA及蛋白表达水平分别为TLR4-/-空白对照组的2.3倍(P<0.05),1.7倍(P<0.05)。③Wild type oxLDL组VSMCs中NF-κB核转位明显增多,IL-1β和TNF-αmRNA表达较Wild type空白对照组分别升高3.9倍(P<0.05),1.7倍(P<0.05);TLR4-/-oxLDL组VSMCs中无明显NF-κB核转位,仅IL-1βmRNA表达较TLR4-/-空白对照组升高1.2倍(P>0.05)。结论 TLR4及其调节的炎性反应参与平滑肌源性泡沫细胞形成过程中ABCA1表达异常。

ALDH1和ABCG2在宫颈鳞癌中的表达及其临床意义

目的:检测肿瘤干细胞标志物乙醛脱氢酶1(ALDH1)和三磷酸腺苷结合盒转运蛋白G2(ABCG2)在不同程度宫颈病变组织中的表达情况。方法:应用免疫组化SP法检测76例宫颈鳞癌、52例宫颈高级别鳞状上皮内病变(HSIL)、37例慢性宫颈炎患者的石蜡组织中ALDH1和ABCG2的表达情况,并进行比较分析。结果:1ALDH1和ABCG2在慢性宫颈炎、HSIL、宫颈鳞癌组织中的阳性表达率分别为5.41%(2/37)和8.11%(3/37)、23.08%(12/52)和28.85%(15/52)、53.95%(41/76)和61.84%(47/76),两者在宫颈鳞癌组织中的阳性表达率明显高于HSIL组织、慢性宫颈炎组织,差异均有统计学意义(P<0.05)。2ALDH1在宫颈鳞癌中表达水平与肿瘤分化程度、是否存在淋巴结转移有关(P<0.05),ABCG2在宫颈鳞癌中表达水平与宫颈癌的临床分期、肿瘤细胞的分化程度及是否有淋巴结转移有关(P<0.05)。3宫颈鳞癌组织中ALDH1和ABCG2表达水平水平呈正相关(r=0.535,P<0.05)。结论:ALDH1和ABCG2在宫颈鳞癌的表达升高,可能在宫颈鳞癌的发生、发展、转移中起作用。ALDH1和ABCG2在宫颈鳞癌的发展过程中可能起协同作用。

Role of interleukin-1 and its antagonism of hepatic stellate cell proliferation and liver fibrosis in the Abcb4^(-/-) mouse model

AIM: To study the interleukin-1(IL-1) pathway as a therapeutic target for liver fibrosis in vitro and in vivo using the ATP-binding cassette transporter b4^(-/-)(Abcb4^(-/-)) mouse model.METHODS: Female and male Abcb4^(-/-) mice from 6 to 13 mo of age were analysed for the degree of cholestasis(liver serum tests), extent of liver fibrosis(hydroxyproline content and Sirius red staining) and tissue-specific activation of signalling pathways such as the IL-1 pathway [quantitative polymerase chain reaction(q PCR)]. For in vivo experiments, murine hepatic stellate cells(HSCs) were isolated via pronasecollagenase perfusion followed by density gradient centrifugation using female mice. Murine HSCs were stimulated with up to 1 ng/m L IL-1β with or without 2.5 μg/m L Anakinra, an IL-1 receptor antagonist, respectively. The proliferation of murine HSCs was assessed via the Brd U assay. The toxicity of Anakinra was evaluated via the fluorescein diacetate hydrolysis(FDH) assay. In vivo 8-wk-old Abcb4^(-/-) mice with an already fully established hepatic phenotype were treated with Anakinra(1 mg/kg body-weight daily intraperitoneally) or vehicle and liver injury and liver fibrosis were evaluated via serum tests, q PCR, hydroxyproline content and Sirius red staining. RESULTS: Liver fibrosis was less pronounced in males than in female Abcb4^(-/-) animals as defined by a lower hydroxyproline content(274 ± 64 μg/g vs 436 ± 80 μg/g liver, respectively; n = 13-15; P < 0.001; MannWhitney U-test) and lower m RNA expression of the profibrogenic tissue inhibitor of metalloproteinase-1(TIMP)(1 ± 0.41 vs 0.66 ± 0.33 fold, respectively; n = 13-15; P < 0.05; Mann-Whitney U-test). Reduced liver fibrosis was associated with significantly lower levels of F4/80 m RNA expression(1 ± 0.28 vs 0.71 ± 0.41 fold, respectively; n = 12-15; P < 0.05; Mann-Whitney U-test) and significantly lower IL-1β m RNA expression levels(1 ± 0.38 vs 0.44 ± 0.26 fold, respectively; n = 13-15; P < 0.001; Mann-Whitney U-test). No gender differences in the serum liver parameters [bilirubin; alanine aminotransferase(ALT); aspartate aminotransferase and alkaline phosphatase(AP)] were found. In vitro, the administration of IL-1β resulted in a significant increase in HSC proliferation [0.94 ± 0.72 arbitrary units(A.U.) in untreated controls, 1.12 ± 0.80 A.U. at an IL-1β concentration of 0.1 ng/m L and 1.18 ± 0.73 A.U. at an IL-1β concentration of 1 ng/m L in samples from n = 6 donor animals; P < 0.001; analyses of variance(ANOVA)]. Proliferation was reduced significantly by the addition of 2.5 μg/m L Anakinra(0.81 ± 0.60 A.U. in untreated controls, 0.92 ± 0.68 A.U. at an IL-1β concentration of 0.1 ng/m L, and 0.91 ± 0.69 A.U. at an IL-1β concentration of 1 ng/m L; in samples from n = 6 donor animals; P < 0.001; ANOVA) suggesting an anti-proliferative effect of this clinically approved IL-1 receptor antagonist. The FDH assay showed this dose to be non-toxic in HSCs. In vivo, Anakinra had no effect on the hepatic hydroxyprolinecontent, liver serum tests(ALT and AP) and profibrotic(collagen 1α1, collagen 1α2, transforming growth factor-β, and TIMP-1) and anti-fibrotic [matrix metalloproteinase 2(MMP2), MMP9 and MMP13 ] gene expression after 4 wk of treatment. Furthermore, the hepatic IL-1β and F4/80 m RNA expression levels were unaffected by Anakinra treatment.CONCLUSION: IL-1β expression is associated with the degree of liver fibrosis in Abcb4^(-/-) mice and promotes HSC proliferation. IL-1 antagonism shows antifibrotic effects in vitro but not in Abcb4^(-/-) mice.

Roles of sulfonylurea receptor 1 and multidrug resistance protein 1 in modulating insulin secretion in human insulinoma

BACKGROUND:Sulfonylurea receptor 1(SUR1)and multidrug resistance protein 1(MRP1)are two prominent members of multidrug resistance proteins associated with insulin secretion. The aims of this study were to investigate their expression in insulinomas and their sole and synergistic effects in modulating abnormal insulin secretion. METHODS:Fasting glucose,insulin and C-peptide were measured in 11 insulinoma patients and 11 healthy controls. Prolonged oral glucose tolerance tests were performed in 6 insulinoma patients.Insulin content,SUR1 and MRP1 were detected in 11 insulinoma patients by immunohistochemistry. SUR1 and MRP1 were also detected in 6 insulinoma patients by immunofluorescence. RESULTS:Insulinoma patients presented the typical demons-trations of Whipple’s triad.Fasting glucose of each insulinoma patient was lower than 2.8 mmol/L,and simultaneous insulin and C-peptide were increased in insulinoma patients. Prolonged oral glucose tolerance tests showed that insulin secretion in insulinoma patients were also stimulated by high glucose.Immunohistochemistry and immunofluorescence staining showed that SUR1 increased,but MRP1 decreased in insulinoma compared with the adjacent islets. CONCLUSIONS:The hypersecretion of insulin in insulinomas might be,at least partially,due to the enrichment of SUR1. In contrast,MRP1,which is down-regulated in insulinomas, might reflect a negative feedback in insulin secretion.

LncRNA SNHG16 promotes colorectal cancer proliferation by regulating ABCB1 expression through sponging miR-214-3p

Mounting evidence indicates that long non-coding RNAs(lncRNAs)have critical roles in colorectal cancer(CRC)progression,providing many potential diagnostic biomarkers,prognostic biomarkers,and treatment targets.Here,we sought to investigate the role and underlying regulatory mechanism of lncRNA small nucleolar RNA host gene 16(SNHG16)in CRC.The expressions of SNHG16 in CRC were identified by RNA-sequencing and quantitative reverse transcription PCR.The functions of SNHG16 were explored by a series of in vitro and in vivo assays(colony formation assay,flow cytometry assay,and xenograft model).Bioinformatics analysis,RNA fluorescence in situ hybridization and luciferase reporter assay were used to investigate the regulatory mechanism of effects of SNHG16.SNHG16 was found to be significantly elevated in human CRC tissues and cell lines.Functional studies suggested that SNHG16 promoted CRC cell growth both in vitro and in vivo.Mechanistically,we identified that SNHG16 is expressed predominantly in the cytoplasm.SNHG16 could interact with miR-214-3p and up-regulated its target ABCB1.This study indicated that SNHG16 plays an oncogenic role in CRC,suggesting it could be a novel biomarker and therapeutic target in CRC.

Role of apolipoproteins,ABCA1 and LCAT in the biogenesis of normal and aberrant high density lipoproteins

In this review, we focus on the pathway of biogenesis of HDL, the essential role of apoA-I, ATP binding cassette transporter A1（ABCA1）, and lecithin： cholesterol acyltransferase（LCAT） in the formation of plasma HDL; the generation of aberrant forms of HDL containing mutant apoA-I forms and the role of apoA-IV and apoE in the formation of distinct HDL subpopulations. The biogenesis of HDL requires functional interactions of the ABCA1 with apoA-I（and to a lesser extent with apoE and apoA-IV） and subsequent interactions of the nascent HDL species thus formed with LCAT. Mutations in apoA-I, ABCA1 and LCAT either prevent or impair the formation of HDL and may also affect the functionality of the HDL species formed. Emphasis is placed on three categories of apoA-I mutations. The first category describes a unique bio-engineered apoA-I mutation that disrupts interactions between apoA-I and ABCA1 and generates aberrant prep HDL subpopulations that cannot be converted efficiently to a subpopulations by LCAT. The second category describes natural and bio-engineered apoA-I mutations that generate preβ and small size a4 HDL subpopulations, and are associated with low plasma HDL levels. These phenotypes can be corrected by excess LCAT. The third category describes bio-engineered apoA-I mutations that induce hypertriglyceridemia that can be corrected by excess lipoprotein lipase and also have defective maturation of HDL.The HDL phenotypes described here may serve in the future for diagnosis, prognoses and potential treatment of abnormalities that affect the biogenesis and functionality of HDL.

Induction of macrophage inflammatory cytokines by Ox-LDL is ABCA1 dependent

Objective The current study aimed to evaluate whether the induction of macrophage inflammatory cytokines by Ox-LDL is related to the expression of ABCA 1 pathway. Methods After THP 1/PMA macrophages were transfected with ABCA1 antisense oligonucleotides （100nmol/L） followed by treatment with Ox-LDL （30mg/L）, the expressions of ABCA1, ICAM-1 and MCP-1 mRNA and protein were determined by real-time fluorescent quantitative RT-PCR, Western blot or ELISA. Results Ox-LDL induced expressions of ABCA1, ICAM-1, and MCP-1 at both mRNA and protein levels from THPI/PMA macrophages. Transfection with ABCAI antisense oligonucleotides reduced ABCA1 mRNA levels after 3 and 6 hours and protein levels after 12 and 24 hours. The expression of ICAM-1 and MCP-1 induced by Ox-LDL was also decreased after inhibition of ABCA 1 protein expression by ABCA 1 antisense oligonucleotide decreased. Conclusion The induction of macrophage inflammatory cytokines by Ox-LDL is partially dependent on expression ofABCA1. Our studies disclose new functions of ABCA1 in macrophages Objective The current study aimed to evaluate whether the induction of macrophage inflammatory eytokines by Ox-LDL is related to the expression of ABCA 1 pathway. Methods After THP 1/PMA macrophages were transfected with ABCA1 antisense oligonucleotides （100nmol/L） followed by treatment with Ox-LDL （30mg/L）, the expressions of ABCA1, ICAM-1 and MCP-1 mRNA and protein were determined by real-time fluorescent quantitative RT-PCR, Western blot or ELISA. Results Ox-LDL induced expressions of ABCA1, ICAM-1, and MCP-1 at both mRNA and protein levels from THPI/PMA macrophages. Transfection with ABCAI antisense oligonucleotides reduced ABCA1 mRNA levels after 3 and 6 hours and protein levels after 12 and 24 hours. The expression of ICAM-1 and MCP-1 induced by Ox-LDL was also decreased after inhibition of ABCA 1 protein expression by ABCA 1 antisense oligonucleotide decreased. Conclusion The induction of macrophage inflammatory cytokines by Ox-LDL is partially dependent on expression ofABCA1. Our studies disclose new functions of ABCA1 in macrophages

EFFECTS OF RAPAMYCIN ON INTRACELLULAR CHOLESTEROL HOMEOSTASIS OF GLOMERULAR MESANGIAL CELL IN THE PRESENCE OF INTERLEUKIN-1β

Objective To investigate the effects of rapamycin on cholesterol homeostasis of glomerular mesangial cells and the underlying mechanisms. Methods Intracellular cholesterol accumulation was measured by Oil Red O staining and high performance liquid chromatography. The effects of rapamycin on interleukin-1β（1L-1β）-induced mRNA and protein changes of low-density lipoprotein receptor （LDLR） and ATP-binding cassette transporter Al （ABCAl） were assayed by quantitative real-time PCR and Western blot. Transient expressions of 3 types of mammalian target of rapamycin （mTOR）, including mTOR-WT （wild type）, mTOR-RR （rapamycin resistant, with kinase activity）, and mTOR-RR-KD （rapamycin resistant, without kinase activity）, were obtained by plasmid transfection. Results Rapamycin had no significant influence on intracellular cholesterol concentration trader normal condition, but it significantly decreased the intracellular cholesterol concentration in the presence of IL-1β. Rapamycin dose-dependently suppressed the increased expression of LDLR induced by IL-1β and up-regulated the suppressed expression of ABCAl caused by IL-1β Transient expression of 3 types of mTOR all reduced ABCAl mRNA expression significantly, which all could be overroded by rapamycin. Conclusions Rapamycin may contribute to the maintaining of glomerular mesangial cell intracellular cholesterol homeostasis under inflammatory state by both reducing cholesterol uptake and increasing cholesterol effiux. And the effect may be not completely mediiated by mTOR.

High nuclear ABCG1 expression is a poor predictor for hepatocellular carcinoma patient survival

Background:ATP-binding cassette transporter G1(ABCG1)regulates cellular cholesterol homeostasis and plays a significant role in tumor immunity.But,for hepatocellular carcinoma(HCC),the role of ABCG1 has not been investigated.Thus,the aim of this study was to evaluate the prognostic value and clinicopathological significance of ABCG1 in HCC.Methods:One hundred and four adult patients with HCC were enrolled,and ABCG1 expression in paired HCC specimens was determined by immunohistochemistry.All these patients were stratified by ABCG1 expression,Kaplan-Meier analysis was used to compare the overall survival(OS)and recurrence-free survival(RFS),and Cox regression analysis was used to determine independent predictors of tumor recurrence.Results:Upregulation of ABCG1 was observed in HCC samples compared to matched tumor-adjacent tissues.Patients with high nuclear ABCG1 expression had lower OS and RFS(P=0.012 and P=0.020,respectively).High nuclear ABCG1 expression was related to larger tumor size(P=0.004)and tumor recurrence(P=0.027).Although ABCG1 was expressed in the cytoplasm,cytosolic expression could not predict the outcome in patients with HCC.A new stratification pattern was established based on the heterogenous ABCG1 expression pattern:high risk(High^(nucleus)/Low^(cytosol)),moderate risk(High^(nucleus)/High^(cytosol) or Low^(nucleus)/Low^(cytosol)),and low risk(Low^(nucleus)/High^(cytosol)).This ABCG1-based risk stratification could distinguish the different OS and RFS in patients with HCC.Multivariate Cox regression analysis indicated that ABCG1 high risk was an independent predictor of poor RFS(P=0.015).Conclusions:High nuclear ABCG1 expression indicates poor prognosis in patients with HCC.Asymmetric distribution of ABCG1 in the nucleus and cytoplasm may have an important role in tumor recurrence.

A <i>wzt</i>Mutant <i>Burkholderia mallei</i>Is Attenuated and Partially Protects CD1 Mice against Glanders

Burkholderia mallei is the etiologic agent of glanders in solipeds and humans. Lipopolysaccharide (LPS) is a major component of cell envelop of this pathogen. O-antigen, the most external component of LPS, is a virulence factor and a protective antigen in many pathogenic bacteria. Two putative proteins named Wzm (integral membrane protein) and Wzt (hydrophilic ATP-binding protein) are believed to make up an ABC-2 transporter of B. mallei that facilitates transport of components of O-antigen from cytosol to outer-membrane. We studied the importance of wzt (encoding Wzt) to growth, LPS O-antigen profile, and pathogenicity of B. mallei. A wzt mutant strain was generated by deleting a portion of the wzt in B. mallei wild type strain ATCC 23344 by gene replacement. Compared to the wild type strain, the wzt mutant displayed slower growth in vitro and less lethality in CD1 mice when inoculated intraperitoneally. The 50% lethal doses (LD50) of the wild type and the wzt mutant strains were 5.9 × 105 and 9.1 × 105 cfu, respectively. CD1 mice inoculated with a non-lethal dose of the wzt mutant produced specific serum immunoglobulins IgG1 and IgG2a and were partially protected against challenge with 11.2 times LD50 of the wild type strain. These findings suggest that the wzt is required for optimal in vitro growth and pathogenesis of B. mallei, and a wzt mutant protects CD1 mice against glanders.

Two pyrrole acids isolated from Phyllanthus emblica L.and their bioactivities

An undescribed pyrrole acid,1-(4′-methoxy-4′-oxobutyl)-1 H-pyrrole-2,5-dicarboxylic acid(1)and one known pyr-role acid(2)were isolated from the fruits of Phyllanthus emblica.The structures of these compounds were elucidated via the comprehensive analyses of IR,HRESIMS,1D and 2D spectroscopic data.A series of biological assays revealed that compounds 1 and 2 could inhibit LPS-induced over-production of nitric oxide(NO),interleukin-6(IL-6),monocyte chemotactic protein 1(MCP-1)and tumor necrosis factor-α(TNF-α)by reducing the phosphorylation of extracellular regulated protein kinases(ERK)and c-Jun N-terminal kinases(JNK)in RAW 264.7 cells.Additionally,compounds 1 and 2 were found to reduce lipid deposition and increase the mRNA expression of ATP-binding cassette transporter A1 in oxidized low-density lipoprotein-treated RAW264.7 macrophages.

High-density lipoprotein and atherosclerosis: Roles of lipid transporters

Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.

New insights into renal lipid dysmetabolism in diabetic kidney disease

Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs,including the kidney.Research suggests that impaired cholesterol metabolism,increased lipid uptake or synthesis,increased fatty acid oxidation,lipid droplet accumulation and an imbalance in biologically active sphingolipids(such as ceramide,ceramide-1-phosphate and sphingosine-1-phosphate)contribute to the development of diabetic kidney disease(DKD).Currently,the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production,oxidative stress,inflammation,or cell death.Therefore,control of renal lipid dysmetabolism is a very important therapeutic goal,which needs to be archived.This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.

A Possible Mechanism Linking Hyperglycemia and Reduced High-density Lipoprotein Cholesterol Levels in Diabetes

This study investigated the role of glucose in the biogenesis of high-density lipoprotein cholesterol(HDL-C).Mouse primary peritoneal macrophages were harvested and maintained in Dulbecco’s modified Eagle’s medium(DMEM) containing glucose of various concentrations.The cells were divided into 3 groups in terms of different glucose concentrations in the cultures:Control group(5.6 mmol/L glucose),high glucose concentration groups(16.7 mmol/L and 30 mmol/L glucose).ATP-binding cassette transporter A1(ABCA1) mRNA expression in the macrophages was detected by semi-quantitative RT-PCR 24,48 and 72 h after glucose treatment.The results showed that ABCA1 mRNA expression in the 16.7 mmol/L glucose group was not significantly different from that in the control group at all testing time points(P>0.05 for each).In the 30 mmol/L glucose group,macrophage ABCA1 mRNA expression was not changed significantly at 24 h(P=0.14),but was substantially decreased by 40.4% at 48 h(P=0.009) and by 48.1% at 72 h(P=0.015) as compared with that in the control group.It was concluded that ABCA1 is of vital importance for HDL-C biogenesis.High glucose may hamper HDL-C biogenesis by decreasing ABCA1 expression,which contributes to low HDL-C level in diabetes.

Regulation of Intestinal Cholesterol Absorption: A Disease Perspective

Hypercholesterolemia promotes atherosclerosis and precise regulation of cholesterol homeostasis is essential. Besides risk factor for cardiovascular disease, abnormalities in cholesterol metabolism have been associated with type 2 diabetes. Cholesterol homeostasis in the body is maintained by de novo synthesis. Furthermore, intestinal cholesterol absorption has recently been considered as an important control point in cholesterol homeostasis. Important insights have been gained into the mechanisms of transport of cholesterol from the intestinal lumen into the enterocytes. Several transporter proteins that appear to be key players in the control of the cholesterol absorption from the intestinal lumen have been identified. Here, we review intestinal cholesterol absorption and the mechanisms underlying alterations in cholesterol absorption under physiological conditions and in diseases such as diabetes mellitus.

Protective Effect of Irbesartan on ATP Binding Cassette Transporter A1 in THP-1 Derived Macrophages

Objectives To explore the protective effect of irbesartan （lrb） under the interference with angiotensin II （Ang II） on ABCA1. Methods Electron microscopy was used to detect the morphous of foam cells. The expression of ABCA1 mRNA and its protein were determined by RT-PCR and Western blotting, respectively. The variance of cellular cholesterol content was measured by zymochemistry via-fluorospeetrophotometer. Results A positive facilitative effect of Ang II on the formation of foam cells was observed. Total cholesterol was increased significantly by Ang II, the expression of ABCA1 was down-regulated obviously by Ang II; Irb could protect ABCA1 against the lesion of Ang II; Total cellular cholesterol content was reduced significantly in Irb ＋ Ang II group; However, considerable alteration about the cholesterol content and the expression of ABCA1 were not observed in Irb group without incubation with Ang II. Conclusions Irb could protect ABCA1 against the lesion of Ang II, which may contribute to its anti-atherosclerotic properties. （ S Chin J Cardiol 2009; 10（4） ： 227 -233）

Attempts to remodel the pathways of gemcitabine metabolism: Recent approaches to overcoming tumours with acquired chemoresistance

Gemcitabine is a cytidine analogue frequently used in the treatment of various cancers.However,the development of chemoresistance limits its effectiveness.Gemcitabine resistance is regulated by various factors,including aberrant genetic and epigenetic controls,metabolism of gemcitabine,the microenvironment,epithelial-to-mesenchymal transition,and acquisition of cancer stem cell properties.In many situations,results using cell lines offer valuable lessons leading to the first steps of important findings.In this review,we mainly discuss the factors involved in gemcitabine metabolism in association with chemoresistance,including nucleoside transporters,deoxycytidine kinase,cytidine deaminase,and ATP-binding cassette transporters,and outline new perspectives for enhancing the efficacy of gemcitabine to overcome acquired chemoresistance.