1,3-dichloro-2-propanol induced lipid accumulation in HepG2 cells through cAMP/protein kinase A and AMP-activated protein kinase pathways via Gi/o-coupled receptors

1,3-dichloro-2-propanol (1,3-DCP) is a food born hepatoxic chloropropanol contaminant that has been detected in a wide range of foods. In the present study, we investigated the effects and mechanisms of 1,3-DCP on lipid accumulation in HepG2 cells. The data showed 1,3-DCP significantly increased intracellular content of triglyceride (TG) and total cholesterol (TC) at 0.5–2 μg/mL. Further results showed that 1,3-DCP greatly decreased cyclic AMP (cAMP) level. In addition, 1,3-DCP inhibited PKA and AMPK signaling pathway, but had no influence on intracellular calcium and regulated proteins. Moreover, Gi/o protein inhibitor PTX significantly inhibited 1,3-DCP induced decrease of cAMP, p-PKA and p-AMPK expression. Furthermore, 1,3-DCP significantly decreased GPR41 and GPR43 expression, but had no effect on GPR109B.Thus, we concluded that 1,3-DCP induced lipid accumulation in HepG2 cells through cAMP/PKA and AMPK signaling pathways via Gi/o-coupled receptor.     

Danthron activates AMP-activated protein kinase and regulates lipid and glucose metabolism in vitro

Aim:

To discover the active compound on AMP-activated protein kinase (AMPK) activation and investigate the effects of the active compound 1,8-dihydroxyanthraquinone (danthron) from the traditional Chinese medicine rhubarb on AMPK-mediated lipid and glucose metabolism in vitro.

Methods:

HepG2 and C2C12 cells were used. Cell viability was determined using MTT assay. Real-time PCR was performed to measure the gene expression. Western blotting assay was applied to investigate the protein phosphorylation level. Enzymatic assay kits were used to detect the total cholesterol (TC), triglyceride (TG) and glucose contents.

Results:

Danthron (0.1, 1, and 10 μmol/L) dose-dependently promoted the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in both HepG2 and C2C12 cells. Meanwhile, danthron treatment significantly reduced the lipid synthesis related sterol regulatory element-binding protein 1c (SREBP1c) and fatty acid synthetase (FAS) gene expressions, and the TC and TG levels. In addition, danthron treatment efficiently increased glucose consumption. The actions of danthron on lipid and glucose metabolism were abolished or reversed by co-treatment with the AMPK inhibitor compound C.

Conclusion:

Danthron effectively reduces intracellular lipid contents and enhanced glucose consumption in vitro via activation of AMPK signaling pathway.     

消渴饮水方对链脲佐菌素联合高脂高糖诱导的糖尿病肾病小鼠的保护作用

目的：研究消渴饮水方（XEC）对实验性2型糖尿病（T2DM）小鼠糖脂代谢及肾病损伤的保护作用及机制。方法：采用链脲佐菌素联合高脂高糖饲料诱导C57BL/6小鼠为T2DM动物模型,分为模型（DM）组、二甲双胍（MET）组、消渴灵片（XKLP）组、消渴饮水方低（XEC-L）、中（XEC-M）、高（XEC-H）剂量组,并以健康小鼠为正常（NC）组,给药6周。每周测空腹血糖,第6周进行口服葡萄糖耐量实验,检测糖化血红蛋白、空腹胰岛素、尿素氮等生化指标;HE染色观察胰腺病理改变,HE、PAS和Masson染色观察肾脏病理改变;蛋白质印迹（Western blot）检测肝脏组织胰岛素受体α（InsRα）、胰岛素受体底物1（IRS-1）、磷酸脂酰激醇-3激酶（PI3K）、蛋白激酶B （AKT）、腺苷酸化蛋白激酶（AMPK）和磷酸化AMPK （p-AMPK）水平,肾脏组织晚期糖基化终末产物受体（RAGE）、核因子-κB （NF-κB）、c-Jun氨基末端激酶（JNK）和磷酸化JNK （p-JNK）水平。结果：XEC显著改善T2DM小鼠的胰岛素抵抗、糖耐量降低和糖脂代谢紊乱（P<0.01）,以及受损的肾功能（P<0.05）。在组织病理分析中,XEC减轻T2DM小鼠胰腺、肾小球和肾小管的结构病变。Western blot分析表明,XEC-H显著上调InsRα、IRS-1、PI3K、AKT的表达和p-AMPK/AMPK比值,降低RAGE、NF-κB的水平和p-JNK/JNK比值（P<0.05）。结论：XEC能够改善T2DM小鼠的糖脂代谢紊乱,在预防治疗糖尿病肾病方面显示出比MET和XKLP更优异的效果。其作用机制可能是通过上调InsRα/IRS-1/PI3K/AKT信号通路,促进AMPK磷酸化及下调肾脏AGE/RAGE和JNK/NF-κB信号通路,实现对糖尿病及肾病的预防和治疗作用。     

The effect of clozapine on the AMPK-ACC-CPT1 pathway in the rat frontal cortex

Clozapine is an antipsychotic drug that has a greater efficacy than other medications in some contexts, especially for the treatment of treatment-resistant schizophrenia. However, clozapine induces more metabolic side-effects involving abnormality in lipid metabolism compared to other antipsychotics. AMP-activated protein kinase (AMPK) plays a central role in controlling lipid metabolism through modulating the downstream acetyl CoA carboxylase (ACC) and carnitine palmitoyl transferase 1 (CPT1) pathway. In this study, we investigated the effect of a single intraperitoneal injection of clozapine on the AMPK-ACC-CPT1 pathway in the rat frontal cortex, which has been implicated as a target site for this antipsychotic drug. At 2 h after injection, the clinically relevant dose of clozapine had activated AMPK, with increased phosphorylation of AMPKα at Thr(172), and had inactivated ACC, with increased phosphorylation of ACC at Ser(79). In addition, clozapine activated the brain-specific isoform of CPT1, CPT1c, whose activity is inhibited by unphosphorylated ACC, in the rat frontal cortex. Immunohistochemistry and immunofluorescence analysis showed that clozapine induced an increase in number of p-AMPKα (Thr(172))- and p-ACC (Ser(79))-positive cells among the neurons of the rat frontal cortex. Taken together, these results show that clozapine activated the AMPK-ACC-CPT1 pathway in the neurons of the rat frontal cortex. These findings indicate that the antipsychotic agent clozapine affects the lipid regulatory system of neurons in the brain.     

益肾排毒丸调节AMPK/ACC信号通路对db/db小鼠肝损伤的保护作用研究

目的：探究益肾排毒丸（YSPDW）对db/db小鼠肝损伤的保护作用及其对脂代谢通路的影响机制。方法：C57BL/6小鼠作为空白对照组、8周龄的db/db小鼠分为非酒精性脂肪肝（non-alcoholic fatty liver disease,NAFLD）模型组、益肾排毒丸治疗组和二甲双胍阳性对照组。给药8周后检测小鼠肝脏系数、随机血糖、肝功能（丙氨转氨酶ALT、谷草转氨酶AST）、血脂（总胆固醇TC、三酰甘油TG、高密度脂蛋白胆固醇HDL-C、低密度脂蛋白胆固醇LDL-C）、肝脏脂质（TC、TG）、肝脏抗氧化因子（谷胱甘肽过氧化物酶GSH-Px、谷胱甘肽GSH、超氧化物歧化酶SOD、丙二醛MDA、过氧化氢酶CAT）、肝脏炎性因子（TNF-α、IL-6、IL-1β、MCP-1）等指标的变化。HE和PAS染色评估小鼠肝脏形态变化、脂肪变性和糖原沉积。Western blot检测脂代谢AMPK/ACC信号通路相关蛋白表达。结果：与模型组相比,益肾排毒丸给药组和二甲双胍组小鼠随机血糖和肝脏系数显著降低。生化指标检测结果显示益肾排毒丸可显著降低NAFLD模型小鼠血清AST、ALT、TC、TG水平和肝组织TC、TG、MDA水平,升高HDL-C含量,发挥肝保护作用;ELISA结果表明益肾排毒丸能明显升高NAFLD小鼠肝组织GSH-Px、GSH和SOD活性,显著降低肝脏炎性细胞因子TNF-α、IL-6、IL-1β和MCP-1的水平,表明益肾排毒丸可增加机体抗氧化能力,抑制炎症因子释放。HE和PAS结果显示益肾排毒丸可明显减轻肝组织脂肪变性和炎症细胞浸润,改善肝细胞的结构和形态完整。Western blot结果表明,益肾排毒丸能激活AMPK/ACC信号通路,显著增加模型小鼠肝脏p-AMPK和p-ACC蛋白表达。结论：益肾排毒丸可能通过促进AMPK/ACC信号通路来改善肝脏氧化应激、炎性反应,减少脂质合成,从而改善NAFLD的肝损伤。     

5′-AMP-activated protein kinase plays an essential role in geniposide-regulated glucose-stimulated insulin secretion in rat pancreatic INS-1 β cells

Our previous work showed that geniposide affected glucose-stimulated insulin secretion (GSIS) via regulating glucose uptake and metabolism in pancreatic β cells; however, the molecular mechanisms remain largely unknown. Substantial evidence suggests that activation of 5′-AMP-activated protein kinase (AMPK) plays a central role in GSIS. Here, we aim to determine the role of AMPK on geniposide-regulated GSIS in rat pancreatic INS-1 cells. The results demonstrated that 6-[4-(2-piperidin-1-yletoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-α] pyrimidine (Compound C; an AMPK inhibitor) significantly attenuated the effects of geniposide on glucose uptake, energy metabolism, and insulin secretion in INS-1 cells. We also observed that geniposide induced phosphorylation of acetyl-CoA carboxylase (ACC), a marker of AMPK activity, in a time-dependent manner in INS-1 cells; however, in the presence of Compound C, the influence of geniposide on ACC phosphorylation was obviously inhibited. Furthermore, the knockdown of AMPK protein with AMPK siRNA treatment decreased the effects of geniposide on glucose uptake, adenosine triphosphate production, and GSIS. All these data indicate that AMPK plays an essential role in geniposide-regulated GSIS in pancreatic β cells.     

Effect of oxymatrine on lipid metabolism regulated genes in liver of fat-induced insulin resistance in ApoE-/-mice北大核心CSCD

Aim To investigate the effect of oxymatrine on lipid metabolism regulated genes in liver in fat-induced insulin resistance in ApoE-/- mice. Methods Seventeen C57BL/6J male mice were selected in normal control group. Sixty-eight ApoE-/- mice with high fat diet for 16 weeks, were randomly divided into model group, oxymatrine low, middle and high dose groups. Then they were gavaged for 8 weeks. Body weight and general biochemical indicators were determined in mice. The mRNA and protein expression levels of LPL, FAT/CD36, CPT1, UCP2, SREBP-1 c, FAS and ACC were examined by real-time PCR and Western blot in the liver. Results Compared with model group, oxymatrine reduced body weight (BW) , fasting blood glucose (FBG), cholesterol (TC) , triglyceride (TG) , free fatty acids (FFA), fasting plasma insulin (FINS) and insulin resistance index(HOMA-IR) (P < 0. 05) , while improved glucose infusion rate (GIR) . Oxymatrine down-regulated the mRNA and protein expression of LPL, FAT/CD36, UCP2, SREBP-1c, FAS and ACC(P <0. 05) ,and up-regulated the mRNA and protein expression of CPT1 in varying degrees (P < 0. 05). Conclusion Oxymatrine can regulate the expression of lipid metabolism regulated genes in liver and improve insulin resistance in ApoE-/- mice induced by high fat diet.     

氢杨梅素改善高脂饮食诱导的肥胖小鼠肝脏脂肪沉积及机制（英文）

有文献报道, SIRT1-AMPK信号通路可能在DHM改善肝脏细胞甘油三酯蓄积、胰岛素抵抗等作用中发挥作用。为此,本课题拟进一步观察DHM对高脂饮食诱导的肥胖小鼠肝脏脂肪沉积的影响,并探讨其可能机制。C57BL/6J小鼠采用普通饲料和高脂饲料喂养,同时分别用或不用低剂量(125 mg/kg)或高剂量(250 mg/kg)的DHM处理16周。实验期间,每两周检测体重一次。16周后,眼眶静脉取血并处死动物,同时取肩胛下、附睾与腹股沟的脂肪并用电子秤进行称重,并记录脂肪重量。全自动生化分析仪检测:血清甘油三酯(triglyceride,TG)、血清总胆固醇(totalcholesterol,TC)、血清高密度脂蛋白(high-densitylipoprotein,HDL)、血清低密度脂蛋白(low-densitylipoprotein,LDL)。取肝脏甲醛固定、HE和油红O染色检测肝脏脂肪沉积情况;比色法检测肝脏MDA和SOD含量; Realtime PCR检测相关指标的基因表达:IL-6、IL-8、TNF-α、乙酰辅酶A羧化酶(acetyl-Co A carboxylase, ACC)、固...     

1,3-Dichloro-2-propanol induced hyperlipidemia in C57BL/6J mice via AMPK signaling pathway

1,3-Dichloro-2-propanol (1,3-DCP) is a well-known contaminant that has been detected in a wide range of foods. Dietary intake represents the greatest source of exposure to 1,3-DCP. In the study, we first found 1,3-DCP could induce hyperlipidemia in C57BL/6J mice below 1 mg/kg/day. We investigated serum lipid profile, liver total cholesterol (TC) and triglyceride (TG), histopathology of Liver and adipose tissue. The results showed 1,3-DCP dose dependently increased serum TG, TC and low-density lipoprotein cholesterol (LDL-C), decreased serum high-density lipoprotein cholesterol (HDL-C), increased relative liver weight, liver TG and TC, relative adipose tissue weight and enlarged the size of adipose cells. Because AMPK signal pathway is important in the process of lipid metabolism, we further investigated the effects of 1,3-DCP on AMPK signaling pathway in murine models. The results showed that 1,3-DCP (0.1–1 mg/kg/day) decreased p-AMPK/tAMPK ratio, p-ACC/tACC ratio, PPARα expression, but increased FAT, SREBP1, HMGCR and FAS expression. These observations indicated that 1,3-DCP induced hyperlipidemia in C57BL/6J mice at least partially through regulating AMPK signaling pathway.     

中介素通过激活AMPK信号通路对脂多糖诱导巨噬细胞极化的影响

目的探讨中介素(intermedin,IMD)对脂多糖(lipopolysaccharide,LPS)诱导小鼠单核巨噬细胞系RAW 264.7极化的影响及其作用机制。方法RAW 264.7细胞随机分为对照组、LPS组、LPS+IMD组、LPS+IMD+CC(AMPK抑制剂Compound C)组。Real time-PCR法检测TNF-α、CD86、iNOS、Arg^-1、CD206 mRNA表达,Western blot法检测p-AMPK、AMPK、TNF-α、IL-6和IL^-10蛋白表达,流式细胞术检测巨噬细胞亚型,ELISA法检测培养基上清IL-6和TNF-α浓度。结果与对照组及LPS组比较,IMD处理可增加AMPK磷酸化水平,增加p-AMPK/AMPK比值;与对照组相比,LPS诱导可导致巨噬细胞发生M1极化,M1型标志分子CD86、TNF-α及iNOS mRNA表达升高,M2型标志分子CD206、Arg^-1 mRNA表达降低,上调促炎因子TNF-α、IL-6表达,降低抑炎因子IL^-10表达,使M1型细胞数量增加,细胞上清中TNF-α、IL-6分泌增加;而IMD处理可抑制LPS诱导的M1极化,AMPK抑制剂Compound C组处理可在一定程度上拮抗这一作用。结论IMD通过激活AMPK信号通路抑制LPS诱导的巨噬细胞M1型极化。     

Tissue distribution of decabrominated diphenyl ether (BDE-209) and its metabolites in sucking rat pups after prenatal and/or postnatal exposure

Growing evidence has shown that decabromodiphenyl ether (BDE-209) can disrupt thyroid hormones and induce neurological and developmental effects, especially for the fetuses and neonates after prenatal or postnatal exposure. The present study was carried out to examine the effects of in utero and lactational exposure to BDE-209 on the absorption and tissue distribution of BDE-209 and its metabolites in offspring. Pregnant Sprague-Dawley rats were given daily oral doses of 5 μmol/kg b.w. BDE-209 in peanut oil during gestational and lactational period or during lactational period only. BDE-209 and its debrominated congeners were analyzed in several maternal tissues, offspring carcass and neonatal tissues. The occurrence of polybrominated diphenyl ethers (PBDEs) and their time profiles in maternal blood, placenta and fetuses/sucking pups indicated that BDE-209 and its debrominated products can be transferred from mother to offspring via in utero or lactational exposure. Nona-BDEs were the predominant congeners in the analyzed pup tissues, and BDE-206 was the most abundant congener while BDE-197/204 was the major congener of octa-BDE. Then the contributions of transplacental and lactational transfer were compared for BDE-209 and its debrominated congeners. The levels of PBDEs in tissues of sucking pups of the in utero and lactational exposure group were much higher than those of only lactationally exposed group. BDE-197/204 was the debrominated congener with the most significant difference between these two groups and the pup brain was the tissue with the most significant difference of the levels of debrominated congeners. The results provide a basis for understanding the possible adverse effects caused by maternal transfer of BDE-209 during the critical periods of development of fetuses and sucking neonates.     

δ-Opioid receptors stimulate the metabolic sensor AMP-activated protein kinase through coincident signaling with G(q/11)-coupled receptors

AMP-activated protein kinase (AMPK) and δ-opioid receptors (DORs) are both involved in controlling cell survival, energy metabolism, and food intake, but little is known on the interaction between these two signaling molecules. Here we show that activation of human DORs stably expressed in Chinese hamster ovary (CHO) cells increased AMPK activity and AMPK phosphorylation on Thr172. DOR-induced AMPK phosphorylation was prevented by pertussis toxin, reduced by protein kinase A (PKA) activators, and unaffected by PKA, transforming growth factor-β-activated kinase 1, mitogen-activated protein kinase, and protein kinase C inhibitors. Conversely, the DOR effect was reduced by Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK) inhibition, apyrase treatment, G(q/11) antagonism, and blockade of P2 purinergic receptors. Apyrase treatment also depressed DOR stimulation of intracellular Ca(2+) concentration, whereas P2 receptor antagonism blocked DOR stimulation of inositol phosphate accumulation. In SH-SY5Y neuroblastoma cells and primary olfactory bulb neurons, DOR activation failed to affect AMPK phosphorylation per se but potentiated the stimulation by either muscarinic agonists or 2-methyl-thio-ADP. Sequestration of G protein βγ subunits (Gβγ) blocked the DOR potentiation of AMPK phosphorylation induced by oxotremorine-M. In CHO cells, the AMPK activator 5-aminoimidazole-4-carboxamide1-β-D-ribonucleoside stimulated AMPK phosphorylation and glucose uptake, whereas pharmacological inhibition of AMPK, expression of a dominant-negative mutant of AMPKα1, and P2Y receptor blockade reduced DOR-stimulated glucose uptake. The data indicate that in different cell systems, DOR activation up-regulates AMPK through a Gβγ-dependent synergistic interaction with G(q/11)-coupled receptors, potentiating Ca(2+) release and CaMKKβ-dependent AMPK phosphorylation. In CHO cells, this coincident signaling mechanism is involved in DOR-induced glucose uptake.     

Effect and mechanism of waterborne prolonged Zn exposure influencing hepatic lipid metabolism in javelin goby Synechogobius hasta

The present study was conducted to determine the effect and mechanism of waterborne Zn exposure influencing hepatic lipid deposition and metabolism in javelin goby Synechogobius hasta. S. hasta were exposed to four waterborne Zn concentrations (Zn 0.005 [control], 0.18, 0.36 and 0.55 mg l^?1, respectively) for 60 days. Sampling occurred at days 20, 40 and 60, respectively. Zn exposure increased Zn content, declined hepatic lipid content and reduced viscerosomatic and hepatosomatic indices and lipogenic enzyme activities, including 6‐phosphogluconate dehydrogenase (6PGD), glucose‐6‐phosphate dehydrogenase (G6PD), malic enzyme (ME) and fatty acid synthase (FAS). At days 20 and 60, Zn exposure decreased hepatic mRNA levels of 6PGD, G6PD, ME, FAS, acetyl‐CoA carboxylase (ACC)α, ACCβ, hormone‐sensitive lipase (HSL)a, HSLb, sterol‐regulator element‐binding protein (SREBP)‐1, peroxisome proliferators‐activated receptor (PPAR)α and PPARγ. However, the mRNA levels of CPT 1 and adipose triglyceride lipase increased following Zn exposure. On day 40, Zn exposure reduced hepatic mRNA expression of 6PGD, G6PD, ME, FAS, ACCα, ACCβ, HSLa, HSLb, SREBP‐1 and PPARγ but increased mRNA expression of CPT 1, adipose triglyceride lipase and PPARα. General speaking, Zn exposure reduced hepatic lipid content by inhibiting lipogenesis and stimulating lipolysis. For the first time, the present study provided evidence that chronic Zn exposure differentially influenced mRNA expression and activities of genes and enzymes involved in lipogenic and lipolytic metabolism in a duration‐dependent manner, and provided new insight into the relationship between metal elements and lipid metabolism. Copyright © 2015 John Wiley & Sons, Ltd.     

双去甲氧基姜黄素对肥胖模型小鼠糖脂代谢的影响及机制

目的 研究双去甲氧基姜黄素(bisdemethoxycurcumin,BDMC)对高糖高脂饮食诱导的肥胖小鼠胰岛素抵抗、糖脂代谢紊乱的影响,并探讨其机制。方法 C57BL/6小鼠40只随机分为正常组(10只)和高糖高脂饮食组(30只),正常组小鼠给予常规饲料,其余小鼠饲喂高糖高脂饮食诱导肥胖,造模8周。造模成功后,高糖高脂饮食组小鼠随机分为模型组、BDMC低剂量组(20 mg·kg^-1)、BDMC高剂量组(40 mg·kg^-1),每组10只。分别按剂量灌胃给药,每日1次,每周5次,连续8周。给药结束后,检测小鼠体质量、肝脏及脂肪重量,观察肝脏病理改变及脂质堆积情况,监测小鼠血糖、血脂、血清胰岛素等生化指标,并考察BDMC对TRPV1、AMPK及下游胰岛素信号、糖脂代谢通路的影响。结果 与正常组相比,模型组小鼠体质量及脏器指数增加,肝脏出现明显的病理改变,脂质堆积严重,血清胰岛素、血糖、血脂参数(TC、TG、LDL-C)显著增高,HDL-C显著降低;肝损伤(ALT、AST)加重;肝脏组织中TRPV1、SREBP、FAS蛋白表达显著升高,p-IRS1、p-AMPK、GLUT4、p-ACC表达显著降低。与模型组相比,给予BDMC治疗后,肝脏脂质堆积减少,组织病理改变得到改善,血糖、血清胰岛素、TC、TG、LDL-C、ALT、AST显著降低(P<0.05),HDL-C显著升高,肝脏中p-IRS1、p-AMPK、GLUT4、p-ACC表达升高,TRPV1、SREBP、FAS表达显著降低(P<0.05)。结论 BDMC能改善胰岛素抵抗,调节糖脂代谢紊乱,治疗高糖高脂饮食诱导的肥胖,其作用可能与调节TRPV1和AMPK信号通路有关。     

Studies on the mechanism of SIRT1/AMPK signaling pathway between hepatocytes and hepatic stellate cells

OBJECTIVE To investigate the mechanism of SIRT1/AMPK signaling pathway between hepatocytes and hepatic stellate cells(HSCs).METHODS Normal human Chang liver cells and human hepatic stellate cell line,LX-2 cells were treated with SRT1720(10μmol·L~(-1))and AICAR(500μmol·L~(-1))prior to ethanol(50 mmol·L~(-1)) for 24 and 48 h.Cell viability was analyzed by methyl thiazolyl tetrazolium assay.SIRT1,AMPK and p-AMPK m RNA levels for 24 h and 48 h were analyzed by RT-PCR,SIRT1,AMPK and p-AMPK protein expressions in the supernatant at 24 and 48 h was detected by Western blot.RESULTS SRT1720 and AICAR effectively decreased LX-2 cell viabilities and exhibited scarcely little toxicity in human Chang liver cells.SRT1720 and AICAR attenuated collagen-I,α-smooth muscle actin(α-SMA)levels,activated liver kinase B-1(LKB1)and AMPK phosphorylation in ethanol treated LX-2 cells.Meanwhile,SRT1720 and AICAR enhanced SIRT1 expression mediated by ethanol both in Chang liver cells and LX-2 cells.Furthermore,SRT1720 and AICAR suppressed the expression of sterol regulatory element-binding protein-1(SREBP-1)to regulate fatty acid synthesis.CONCLUSION SIRT1 agonist and AMPK agonist blocked the crosstalk between hepatocytes and HSCs via SIRT1/AMPK signaling pathway to modulate hepatocytes accumulation of lipid and HSCs activation.     

芒果苷对胰岛素抵抗HepG2细胞糖脂代谢的影响

目的:分析芒果苷(MGF)对胰岛素抵抗HepG2细胞(IR-HepG2细胞)糖脂代谢的影响,并探讨潜在机制.方法:以人肝癌HepG2细胞为对象,以1 mmol/L棕榈酸+2 mmol/L油酸联合培养建立IR-HepG2细胞模型.以盐酸二甲双胍为阳性对照,分别检测低、中、高浓度MGF(125、250、500μmol/L)...     

Monacolin K affects lipid metabolism through SIRT1/AMPK pathway in HepG2 cells

Monacolin K is the secondary metabolite isolated from Monascus spp. It is the natural form of lovastatin, which is clinically used to reduce the synthesis of cholesterol by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A reductase. In the present study, monacolin K increased protein expression of SIRT1 and phosphorylation level of AMP-activated protein kinase (AMPK) in HepG2 cells. Through activation of SIRT1/AMPK pathway, monacolin K increased phosphorylation of acetyl CoA carboxylase and caused nuclear translocation of forkhead box O1. The western blotting results showed that monacolin K increased expression of adipose triglyceride lipase but decreased abundances of fatty acid synthase (FAS) and sterol regulatory element-binding protein 1 (SREBP1). Monacolin K also decreased the intracellular accumulation of lipids as demonstrated by Oil Red O staining. In addition, the immunostaining showed that monacolin K prevented the nuclear translocation of SREBP1, indicating the association with down-regulation of FAS. All the demonstrated effects of monacolin K were counteracted by nicotinamide or compound C, the inhibitors of SIRT1 or AMPK. In summary, monacolin K reduces the lipid content through SIRT1/AMPK pathway in HepG2 cells, which promotes catabolism and inhibits anabolism of lipid.     

Formaldehyde alters triglyceride synthesis and very low-density lipoprotein secretion in a time-dependent manner

Formaldehyde is a common indoor air pollutant that is toxic to the liver. This study aimed to investigate the effects of formaldehyde on triglyceride metabolism in human hepatocellular carcinoma cells (HepG2). Cell viability was detected using a MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay. Following treatment with different concentrations of formaldehyde for 24 and 48 h, the intra and extra-hepatocellular triglyceride (TG) content was determined using a chemical-enzymatic method; Western blotting was used to detect the levels of fatty acid synthesis and VLDL-related proteins. Our results showed that cell viability significantly decreased after formaldehyde treatment (0.5–12.5 mM, 24/48 h). Extracellular TG levels in the hepatocytes increased after formaldehyde treatment at 0.004 mM–0.1 mM for 24 h. SREBP-1c, ACC, FASN, and MTP, CES3 and DGAT1 proteins increased significantly after 24 h of formaldehyde treatment. Intracellular TG levels decreased for 48 h treatment of formaldehyde. AMPKα increased significantly in all tested groups and p-AMPK increased significantly after 0.1 mM formaldehyde treatment for 48 h. Our results indicated that short–term formaldehyde exposure balances triglyceride metabolism by promoting hepatocellular TG synthesis and VLDL secretion; Long-term formaldehyde disturbs the TG metabolism balance in the hepatocytes.     

正常人肝细胞和肝癌细胞对力达霉素诱导的有丝分裂性细胞死亡的差异

[摘要]目的：探讨力达霉素（lidamycin, LDM）诱导人肝癌BEL-7402和正常人肝L-02细胞出现的有丝分裂性细胞死亡的差异。方法：采用MTT法观察LDM对BEL-7402和L-02细胞生长曲线的影响;使用Giemsa染色和流式细胞术观察有丝分裂性细胞死亡特征;用Western blot法检测蛋白表达变化。结果：LDM抑制BEL-7402和L-02细胞的生长,二者均表现出有丝分裂性细胞死亡的特征,即细胞体积增大、G2/M期阻滞、出现多核化,但BEL-7402细胞对LDM更敏感。在LDM处理的BEL-7402和L-02细胞中,与凋亡相关的Bax和Smac的蛋白表达水平没有增加,caspase-3和caspase-9未被活化,但L-02细胞的Akt通路被激活。结论：人正常L-02细胞对LDM引起的有丝分裂性细胞死亡明显低于人肝癌BEL-7402细胞,对LDM的反应敏感性存在差异的原因可能与Akt信号通路有关。