Background： Lipid storage myopathy （LSM） is a genetically heterogeneous group with variable clinical phenotypes. Late-onset multiple acyl-coenzyme A dehydrogenation deficiency （MADD） is a rather common form of LS...Background： Lipid storage myopathy （LSM） is a genetically heterogeneous group with variable clinical phenotypes. Late-onset multiple acyl-coenzyme A dehydrogenation deficiency （MADD） is a rather common form of LSM in China. Diagnosis and clinical management of it remain challenging, especially without robust muscle biopsy result and genetic detection. As the noninvasion and convenience, muscle magnetic resonance imaging （MRI） is a helpful assistant, diagnostic tool for neuromuscular disorders. However, the disease-specific MRI patterns of muscle involved and its diagnostic value in late-onset MADD have not been systematic analyzed. Methods： We assessed the MRI pattern and fat infiltration degree of the lower limb muscles in 28 late-onset MADD patients, combined with detailed clinical features and gene spectrum. Fat infiltration degree of the thigh muscle was scored while that ofgluteus was described as obvious or not. Associated muscular atrophy was defined as obvious muscle bulk reduction. Results： The mean scores were significantly different among the anterior, medial, and posterior thigh muscle groups. The mean of fat infiltration scores on posterior thigh muscle group was significantly higher than either anterior or medial thigh muscle group （P 〈 0.00 l）. Moreover, the mean score on medial thigh muscle group was significantly higher than that of anterior thigh muscle group （P 〈 0.01）. About half of the patients displayed fat infiltration and atrophy in gluteus muscles. Of 28 patients, 12 exhibited atrophy in medial and/ or posterior thigh muscle groups, especially in posterior thigh muscle group. Muscle edema pattern was not found in all the patients. Conclusions： Late-onset MADD patients show a typical muscular imaging pattern of fat infiltration and atrophy on anterior, posterior, and medial thigh muscle groups, with major involvement of posterior thigh muscle group and gluteus muscles and a sparing involvement of anterior thigh compartment. Our findings also suggest that mus展开更多
Long-chain acyl-coenzyme A(CoA)synthase 4(ACSL4)is an enzyme that esterifies CoA into specific polyunsaturated fatty acids,such as arachidonic acid and adrenic acid.Based on accumulated evidence,the ACSL4-catalyzed bi...Long-chain acyl-coenzyme A(CoA)synthase 4(ACSL4)is an enzyme that esterifies CoA into specific polyunsaturated fatty acids,such as arachidonic acid and adrenic acid.Based on accumulated evidence,the ACSL4-catalyzed biosynthesis of arachidonoyl-CoA contributes to the execution of ferroptosis by triggering phospholipid peroxidation.Ferroptosis is a type of programmed cell death caused by iron-dependent peroxidation of lipids;ACSL4 and glutathione peroxidase 4 positively and negatively regulate ferroptosis,respectively.In addition,ACSL4 is an essential regulator of fatty acid(FA)metabolism.ACSL4 remodels the phospholipid composition of cell membranes,regulates steroidogenesis,and balances eicosanoid biosynthesis.In addition,ACSL4-mediated metabolic reprogramming and antitumor immunity have attracted much attention in cancer biology.Because it facilitates the cross-talk between ferroptosis and FA metabolism,ACSL4 is also a research hotspot in metabolic diseases and ischemia/reperfusion injuries.In this review,we focus on the structure,biological function,and unique role of ASCL4 in various human diseases.Finally,we propose that ACSL4 might be a potential therapeutic target.展开更多
Acyl-coenzyme A thioesters(acyl-CoAs)denote a key class of intermediary metabolites that lies at the hub of major metabolic pathways.The great diversity in polarity between short-and long-chain acylCoAs makes it techn...Acyl-coenzyme A thioesters(acyl-CoAs)denote a key class of intermediary metabolites that lies at the hub of major metabolic pathways.The great diversity in polarity between short-and long-chain acylCoAs makes it technically challenging to cover an inclusive range of acyl-CoAs within a single method.Levels of acyl-carnitines,which function to convey fatty acyls into mitochondria matrix forβ-oxidation,indicate the efficiency of mitochondrial import and utilization of corresponding acyl-CoAs.Herein,we report a robust,integrated platform to allow simultaneous quantitation of endogenous acyl-CoAs and acyl-carnitines.Using this method,we monitored changes in intermediary lipid profiles across Drosophila development under control(ND)and high-fat diet(HFD).We observed specific accumulations of medium-chain(C8-C12)and long-chain(≥C16)acyl-carnitines distinct to L3 larval and pupal stages,respectively.These observations suggested development-specific,chain length-dependent disparity in metabolic fates of acyl-CoAs across Drosophila development,which was validated by deploying the same platform to monitor isotope incorporation introduced from labelled 12:0 and 16:0 fatty acids into extra-and intra-mitochondrial acyl-CoA pools.We found that pupal mitochondria preferentially import and oxidise C12:0-CoAs(accumulated as C12:0-carnitines in L3 stage)over C16:0-CoAs.Preferential oxidation of medium-chain acyl-CoAs limits mitochondrial utilization of long-chain acyl-CoAs(C16-C18),leading to pupal-specific accumulation of long-chain acyl-carnitines mediated by enhanced CPT1-6 A activity.HFD skewed C16:0-CoAs towards catabolism over anabolism in pupa,thereby adversely affecting overall development.Our developed platform emphasizes the importance of integrating biological knowledge in the design of pathway-oriented platforms to derive maximal physiological insights from analysis of complex biological systems.展开更多
Gastric cancer(GC)is one of the most common gastrointestinal tumors.As a newly discovered type of non-coding RNAs,transfer RNA(tRNA)-derived small RNAs(tsRNAs)play a dual biological role in cancer.Our previous studies...Gastric cancer(GC)is one of the most common gastrointestinal tumors.As a newly discovered type of non-coding RNAs,transfer RNA(tRNA)-derived small RNAs(tsRNAs)play a dual biological role in cancer.Our previous studies have demonstrated the potential of tRF-23-Q99P9P9NDD as a diagnostic and prognostic biomarker for GC.In this work,we confirmed for the first time that tRF-23-Q99P9P9NDD can promote the proliferation,migration,and invasion of GC cells in vitro.The dual luciferase reporter gene assay confirmed that tRF-23-Q99P9P9NDD could bind to the 3'untranslated region(UTR)site of acyl-coenzyme A dehydrogenase short/branched chain(ACADSB).In addition,ACADSB could rescue the effect of tRF-23-Q99P9P9NDD on GC cells.Next,we used Gene Ontology(GO),the Kyoto Encyclopedia of Genes and Genomes(KEGG),and Gene Set Enrichment Analysis(GSEA)to find that downregulated ACADSB in GC may promote lipid accumulation by inhibiting fatty acid catabolism and ferroptosis.Finally,we verified the correlation between ACADSB and 12 ferroptosis genes at the transcriptional level,as well as the changes in reactive oxygen species(ROS)levels by flow cytometry.In summary,this study proposes that tRF-23-Q99P9P9NDD may affect GC lipid metabolism and ferroptosis by targeting ACADSB,thereby promoting GC progression.It provides a theoretical basis for the diagnostic and prognostic monitoring value of GC and opens upnew possibilities for treatment.展开更多
Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods Palmitic acid (PA), the most abun...Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods 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). Results In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression (P<0.01), 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 P<0.05). 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 (P<0.05). Conclusion SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.展开更多
ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol...ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.展开更多
The enzymes of the acyl-coenzyme A:cholesterol acyltransferase(ACAT)family are responsible for the in vivo synthesis of neutral lipids.They are potential drug targets for the intervention of atherosclerosis,hyperlipid...The enzymes of the acyl-coenzyme A:cholesterol acyltransferase(ACAT)family are responsible for the in vivo synthesis of neutral lipids.They are potential drug targets for the intervention of atherosclerosis,hyperlipidemia,obesity,type II diabetes and even Alzheimer’s disease.ACAT family enzymes are integral endoplasmic reticulum(ER)membrane proteins and can be divided into ACAT branch and acyl-coenzyme A:diacylglycerol acyltransferase 1(DGAT1)branch according to their substrate specificity.The ACAT branch catalyzes synthesis of cholesteryl esters using long-chain fatty acyl-coenzyme A and cholesterol as substrates,while the DGAT1 branch catalyzes synthesis of triacylglycerols using fatty acylcoenzyme A and diacylglycerol as substrates.In this review,we mainly focus on the recent progress in the structural research of ACAT family enzymes,including their disulfide linkage,membrane topology,subunit interaction and catalysis mechanism.展开更多
Objective 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 e...Objective 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.Methods 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.Results 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 μg/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.Conclusions 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.展开更多
Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-...Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-1） in phorbol myristate acetate （PMA）-pretreated THP-1 cells after the inducement of advanced glycation end products （AGEs）. Methods： After THP-1 cells were cultured in the presence of 0.1 μmol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations （1, 5 or 10 μmol/L） and then exposed to AGEs-modified bovine serum albumin （AGEs-BSA） for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction （RT-PCR） and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results： Administration of AGEs-BSA （200 mg/L） into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPMI1640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion： PPARy activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.展开更多
基金grants from the National Natural Science Foundation of China，the National Key Clinical Specialty Discipline Construction Program,and Fujian Key Clinical Specialty Discipline Construction Program
文摘Background： Lipid storage myopathy （LSM） is a genetically heterogeneous group with variable clinical phenotypes. Late-onset multiple acyl-coenzyme A dehydrogenation deficiency （MADD） is a rather common form of LSM in China. Diagnosis and clinical management of it remain challenging, especially without robust muscle biopsy result and genetic detection. As the noninvasion and convenience, muscle magnetic resonance imaging （MRI） is a helpful assistant, diagnostic tool for neuromuscular disorders. However, the disease-specific MRI patterns of muscle involved and its diagnostic value in late-onset MADD have not been systematic analyzed. Methods： We assessed the MRI pattern and fat infiltration degree of the lower limb muscles in 28 late-onset MADD patients, combined with detailed clinical features and gene spectrum. Fat infiltration degree of the thigh muscle was scored while that ofgluteus was described as obvious or not. Associated muscular atrophy was defined as obvious muscle bulk reduction. Results： The mean scores were significantly different among the anterior, medial, and posterior thigh muscle groups. The mean of fat infiltration scores on posterior thigh muscle group was significantly higher than either anterior or medial thigh muscle group （P 〈 0.00 l）. Moreover, the mean score on medial thigh muscle group was significantly higher than that of anterior thigh muscle group （P 〈 0.01）. About half of the patients displayed fat infiltration and atrophy in gluteus muscles. Of 28 patients, 12 exhibited atrophy in medial and/ or posterior thigh muscle groups, especially in posterior thigh muscle group. Muscle edema pattern was not found in all the patients. Conclusions： Late-onset MADD patients show a typical muscular imaging pattern of fat infiltration and atrophy on anterior, posterior, and medial thigh muscle groups, with major involvement of posterior thigh muscle group and gluteus muscles and a sparing involvement of anterior thigh compartment. Our findings also suggest that mus
基金supported by the Key Program of General Program of the National Natural Science Foundation of China(NSFC)(No.81730018)Natural Science Foundation of Hunan Province(No.2021JC0003)
文摘Long-chain acyl-coenzyme A(CoA)synthase 4(ACSL4)is an enzyme that esterifies CoA into specific polyunsaturated fatty acids,such as arachidonic acid and adrenic acid.Based on accumulated evidence,the ACSL4-catalyzed biosynthesis of arachidonoyl-CoA contributes to the execution of ferroptosis by triggering phospholipid peroxidation.Ferroptosis is a type of programmed cell death caused by iron-dependent peroxidation of lipids;ACSL4 and glutathione peroxidase 4 positively and negatively regulate ferroptosis,respectively.In addition,ACSL4 is an essential regulator of fatty acid(FA)metabolism.ACSL4 remodels the phospholipid composition of cell membranes,regulates steroidogenesis,and balances eicosanoid biosynthesis.In addition,ACSL4-mediated metabolic reprogramming and antitumor immunity have attracted much attention in cancer biology.Because it facilitates the cross-talk between ferroptosis and FA metabolism,ACSL4 is also a research hotspot in metabolic diseases and ischemia/reperfusion injuries.In this review,we focus on the structure,biological function,and unique role of ASCL4 in various human diseases.Finally,we propose that ACSL4 might be a potential therapeutic target.
基金supported by the National Key R&D Program of China(2018YFA0506900,2018YFA0800901)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA12030211)the National Natural Science Foundation of China(31671226,31871194)。
文摘Acyl-coenzyme A thioesters(acyl-CoAs)denote a key class of intermediary metabolites that lies at the hub of major metabolic pathways.The great diversity in polarity between short-and long-chain acylCoAs makes it technically challenging to cover an inclusive range of acyl-CoAs within a single method.Levels of acyl-carnitines,which function to convey fatty acyls into mitochondria matrix forβ-oxidation,indicate the efficiency of mitochondrial import and utilization of corresponding acyl-CoAs.Herein,we report a robust,integrated platform to allow simultaneous quantitation of endogenous acyl-CoAs and acyl-carnitines.Using this method,we monitored changes in intermediary lipid profiles across Drosophila development under control(ND)and high-fat diet(HFD).We observed specific accumulations of medium-chain(C8-C12)and long-chain(≥C16)acyl-carnitines distinct to L3 larval and pupal stages,respectively.These observations suggested development-specific,chain length-dependent disparity in metabolic fates of acyl-CoAs across Drosophila development,which was validated by deploying the same platform to monitor isotope incorporation introduced from labelled 12:0 and 16:0 fatty acids into extra-and intra-mitochondrial acyl-CoA pools.We found that pupal mitochondria preferentially import and oxidise C12:0-CoAs(accumulated as C12:0-carnitines in L3 stage)over C16:0-CoAs.Preferential oxidation of medium-chain acyl-CoAs limits mitochondrial utilization of long-chain acyl-CoAs(C16-C18),leading to pupal-specific accumulation of long-chain acyl-carnitines mediated by enhanced CPT1-6 A activity.HFD skewed C16:0-CoAs towards catabolism over anabolism in pupa,thereby adversely affecting overall development.Our developed platform emphasizes the importance of integrating biological knowledge in the design of pathway-oriented platforms to derive maximal physiological insights from analysis of complex biological systems.
文摘目的探讨香青兰Dracocephalum moldovica总黄酮对小鼠腹腔巨噬细胞源性泡沫细胞形成的影响及其可能机制。方法以氧化低密度脂蛋白(Ox-LDL)诱导小鼠腹腔巨噬细胞建立泡沫细胞的模型,并以不同质量浓度的香青兰总黄酮进行干预。分别采用油红O染色观察泡沫细胞,荧光分光光度法检测细胞内胆固醇酯的量,荧光定量PCR法检测细胞内酰基辅酶A-胆固醇酰基转移酶1(ACAT-1)m RNA的表达水平,流式细胞术检测细胞表面清道夫受体A(SR-A)的表达水平。结果香青兰总黄酮能显著抑制Ox-LDL诱导的泡沫细胞的形成、细胞内胆固醇酯的积聚、细胞中ACAT-1 m RNA及细胞表面SR-A分子的表达水平,且呈一定的剂量依赖性。结论香青兰总黄酮通过抑制巨噬细胞源性泡沫细胞的形成,可能是其治疗动脉粥样硬化的药效机制之一。
基金was supported by the National Natural Science Foundation of China(Nos.82272411 and 82072363)the Jiangsu Provincial Medical Key Discipline(Laboratory)(No.ZDXK202240)the Science and Technology Project of Jiangsu Province(No.BE2023741),China。
文摘Gastric cancer(GC)is one of the most common gastrointestinal tumors.As a newly discovered type of non-coding RNAs,transfer RNA(tRNA)-derived small RNAs(tsRNAs)play a dual biological role in cancer.Our previous studies have demonstrated the potential of tRF-23-Q99P9P9NDD as a diagnostic and prognostic biomarker for GC.In this work,we confirmed for the first time that tRF-23-Q99P9P9NDD can promote the proliferation,migration,and invasion of GC cells in vitro.The dual luciferase reporter gene assay confirmed that tRF-23-Q99P9P9NDD could bind to the 3'untranslated region(UTR)site of acyl-coenzyme A dehydrogenase short/branched chain(ACADSB).In addition,ACADSB could rescue the effect of tRF-23-Q99P9P9NDD on GC cells.Next,we used Gene Ontology(GO),the Kyoto Encyclopedia of Genes and Genomes(KEGG),and Gene Set Enrichment Analysis(GSEA)to find that downregulated ACADSB in GC may promote lipid accumulation by inhibiting fatty acid catabolism and ferroptosis.Finally,we verified the correlation between ACADSB and 12 ferroptosis genes at the transcriptional level,as well as the changes in reactive oxygen species(ROS)levels by flow cytometry.In summary,this study proposes that tRF-23-Q99P9P9NDD may affect GC lipid metabolism and ferroptosis by targeting ACADSB,thereby promoting GC progression.It provides a theoretical basis for the diagnostic and prognostic monitoring value of GC and opens upnew possibilities for treatment.
基金Supported by National Natural Science Foundation of China (30721063)National High Technology Research and Development Program of China (863 Program) (2006AA02A406)+1 种基金National Basic Research Program of China (973 Program) (2006CB503801)Special Fund of the National Laboratory of China (2060204)
文摘Objective To verify the regulation of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT 2), which is associated with cholesterol metabolism, by saturated fatty acids (SFAs). Methods 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). Results In the three types of hepatic cells treated with PA, that SFA induced significant increase of ACAT2 expression (P<0.01), 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 P<0.05). 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 (P<0.05). Conclusion SFA may regulate ACAT2 expression in human and mouse hepatic cells and in mouse livers.
基金Supported by USDA/CSREES Competitive Grant 98-35206-6286federal funds from the USDA,ARS under Cooperative Agreement no.58-6250-1-003
文摘ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.
文摘The enzymes of the acyl-coenzyme A:cholesterol acyltransferase(ACAT)family are responsible for the in vivo synthesis of neutral lipids.They are potential drug targets for the intervention of atherosclerosis,hyperlipidemia,obesity,type II diabetes and even Alzheimer’s disease.ACAT family enzymes are integral endoplasmic reticulum(ER)membrane proteins and can be divided into ACAT branch and acyl-coenzyme A:diacylglycerol acyltransferase 1(DGAT1)branch according to their substrate specificity.The ACAT branch catalyzes synthesis of cholesteryl esters using long-chain fatty acyl-coenzyme A and cholesterol as substrates,while the DGAT1 branch catalyzes synthesis of triacylglycerols using fatty acylcoenzyme A and diacylglycerol as substrates.In this review,we mainly focus on the recent progress in the structural research of ACAT family enzymes,including their disulfide linkage,membrane topology,subunit interaction and catalysis mechanism.
基金Supported by National Natural Science Foundation of China (30700373)
文摘Objective 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.Methods 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.Results 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 μg/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.Conclusions 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.
文摘Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-1） in phorbol myristate acetate （PMA）-pretreated THP-1 cells after the inducement of advanced glycation end products （AGEs）. Methods： After THP-1 cells were cultured in the presence of 0.1 μmol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations （1, 5 or 10 μmol/L） and then exposed to AGEs-modified bovine serum albumin （AGEs-BSA） for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction （RT-PCR） and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results： Administration of AGEs-BSA （200 mg/L） into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPMI1640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion： PPARy activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.
