Effect of insulin and metformin on methylation and glycolipid metabolism of peroxisome proliferator-activated receptor γcoactivator-1A of rat offspring with gestational diabetes mellitus

Objective:To discuss the effect of insulin and metformin on amethylation and glycolipid metabolism of peroxisome proliferator-activated receptor γ coactivator-1A(PPARGC1A) of rat offspring with gestational diabetes mellitus(GDM).Methods:A total of 45 pregnant rats received the intraperitoneal injection of streptozotocin to establish the pregnant rat model of GDM.A total of 21 pregnant rats with GDM were randomly divided into three groups,with 7ruts in each group,namely the insulin group,metformin group and control group.Rats in the insulin group received the abdominal subcutaneous injection of 1 mL/kg recombinant insulin glargine at 18:00 every day.Rats in the metformin group received the intragastric infusion of metformin hydrochloride at 18:00 every day,with the first dose of 300 mg/kg.The doses of two groups were adjusted every 3 d to maintain the blood glucose level at 2.65-7.62 mmol/L.Rats in the control group received the intragastric infusion of 1 mL normal saline at 18:00 every day.After the natural delivery of pregnant rats.10 offspring rats were randomly selected from each group.At birth,4 wk and 8 wk after the birth of offspring rats,the weight of offspring rats was measured.The blood glucose level of offspring rats was measured at 4wk and 8 wk,while the level of serum insulin,triglyceride and leptin was measured at 8 wk.Results:The weight of offspring rats at birth in the insulin group and metformin group was significantly lower than the one in the control group(P<0.05),and there was no significant difference at 4 wk and 8 wk among three groups(P>0.05).The fasting blood glucose and random blood glucose in the insulin group and metformin group at 4 wk and 8 wk were all significantly lower than ones in the control group(P<0.05);there was no significant difference between the insulin group and metformin group(P>0.05).The expression of PPARGC1 A mRNA in the insulin group and metformin group was significantly higher and the methylation level of PPARGC1 A was significantly lower than the one in the control group(P<0.05),but there was no significant difference between the insulin group and metformin group(P>0.05).Insulin and leptin at 8 wk in the insulin group and metformin group were significantly higher,while triglyceride was significantly lower than the one in the control group(P<0.05);triglyceride level of rats in the insulin group was significantly higher than the one in the metformin group(P<0.05).There was no significant difference in insulin and leptin level of offspring rats between the insulin group and metformin group(P>0.05).Conclusions:GDM can induce the methylation of PPARGC1 A of offspring rats to reduce the expression of PPARGC1 A mRNA and then cause the disorder of glycolipid metabolism when the offspring rats grow up;the insulin or metformin in the treatment of pregnant rats with GDM can reduce the methylation level of PPARGC1 A and thus improve the abnormal glycolipid metabolism of offspring rats.

Role of Neuropeptide Y and Peroxisome Proliferator-activated Receptor γ Coactivator-1α in Stress Cardiomyopathy

Death following situations of intense emotional stress has been linked to the cardiac pathology described as stress cardiomyopathy, whose pathomechanism is still not clear. In this study, we sought to determine, via an animal model, whether the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α) and the amino peptide neuropeptide Y (NPY) play a role in the pathogenesis of this cardiac entity. Male Sprague-Dawley rats in the experimental group were subjected to immobilization in a plexy glass box for 1 h, which was followed by low voltage elec-tric foot shock for about 1h at 10s intervals in a cage fitted with metallic rods. After 25 days the rats were sacrificed and sections of their hearts were processed. Hematoxylin-eosin staining of cardiac tissues revealed the characteristic cardiac lesions of stress cardiomyopathy such as contraction band necrosis, inflammatory cell infiltration and fibrosis. The semi-quantitative RT-PCR analysis for PGC-1α mRNA expression showed significant overexpression of PGC1-α in the stress-subjected rats (P<0.05). Fluorescence immunohistochemistry revealed a higher production of NPY in the stress-subjected rats as compared to the control rats (P=0.0027). Thus, we are led to conclude that following periods of intense stress, an increased expression of PGC1-α in the heart and an overflow of NPY may lead to stress car-diomyopathy and even death in susceptible victims. Moreover, these markers can be used to identify stress cardiomyopathy as the cause of sudden death in specific cases.

Inhibitory roles of protein kinase B and peroxisome proliferator-activated receptor gamma coactivator on hepatic HMG-CoA reductase promoter activity

Since we had previously demonstrated that siRNAs to tristetraprolin (TTP) markedly inhibited insulin stimulation of hepatic HMG-CoA reductase (HMGR) transcription, we investigated the effects of transfecting rat liver with TTP constructs. We found that transfecting diabetic rats with TTP did not increase HMGR transcription but rather led to modest inhibition. We then investigated whether co-transfection with protein kinase B, hepatic form (AKT2), might lead to phosphorylation and result in activation of HMGR transcription. We found that this treatment resulted in near complete inhibition of transcription. Transfection with peroxisome proliferator-activated receptor g coactivator (PGC-1a) also inhibited HMGR transcription. These results show that although TTP is needed for activation of HMGR transcription, it cannot by itself activate this process. AKT2 and PGC-1a, which mediate the activation of gluconeogenic genes by insulin, exert the opposite effect on HMGR.

Peroxisome proliferator-activated receptor gamma inhibits hepatic fibrosis in rats

BACKGROUND:Hepatic fibrosis is a necessary step in the development of hepatic cirrhosis.In this study we used lentiviral vector-mediated transfection technology to evaluate the effect of peroxisome proliferator-activated receptor gamma(PPAR-γ) on rat hepatic fibrosis. METHODS:Hepatic fibrosis in rats was induced by CCl4 for 2 weeks(early fibrosis)and 8 weeks(sustained fibrosis).The rats were randomly divided into four groups:normal control, fibrosis,blank vector,and PPAR-γ.They were infected with the recombinant lentiviral expression vector carrying the rat PPAR-γgene by portal vein injection.The liver of the rats was examined histologically and hydroxyproline was assessed.In vitro primary hepatic stellate cells(HSCs)were infected with the recombinant lentiviral expression vector carrying the rat PPAR-γgene.The status of HSC proliferation was measured by the MTT assay.The protein levels of PPAR-γ,α-smooth muscle actin(α-SMA)and type I collagen expression were evaluated by the Western blotting method. RESULTS:In vitro studies revealed that expression of PPAR-γ inhibited expression ofα-SMA and type I collagen in activated HSCs(P<0.01)as well as HSC proliferation(P<0.01).In vivo experiments indicated that in the early hepatic fibrosis group,the hydroxyproline content and the level of collagen I protein in the liver in the PPAR-γtransfected group were not significantly different compared to the hepatic fibrosis group and the blank vector group;whereas the expressions of PPAR-γ andα-SMA were different compared to the hepatic fibrosis group(P<0.01).In the sustained hepatic fibrosis group,there were significant differences in the hydroxyproline content and the expression of PPAR-γ,α-SMA,and type I collagen between each group.CONCLUSION:PPAR-γcan inhibit HSC proliferation and hepatic fibrosis,and suppressα-SMA and type I collagen expression.

THE INCREASE IN PLASMINOGEN ACTIVATOR INHIBITOR TYPE-1 EXPRESSION BY STIMULATION OF ACTIVATORS FOR PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS IN HUMAN ENDOTHELIAL CELLS

Objective.To investigate the effect of peroxis ome proliferator-activated recept ors(PPARs )activators on plasminogen activator inhibitor ty pe-1(PAI-1)expression in human umbilical vein e ndothelial cells and the possi-ble mechanism.Methods.Human umbilical vein endothelial ce lls(HUVECs )were obtained from normal fetus,and cul-tured conventionally.Then the HUVECs were exposed to test agents(linolenic acid,linoleic acid,oleic acid,stearic acid and prostaglandin J 2 respectively)in varying concentrations with fresh media.RT -PCR and ELISA were applied to determine the expression of PPARs and PAI-1in HUVECs.Results.PPARα,PPARδand PPARγmRNA were detected by using RT-PCR in HUVECs.Treatment of HUVECs with PPARαand PPARγactivators---linolenic acid,linoleic acid,oleic acid and prostaglandin J 2 respectively,but not with stearic a cid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner.However,the mRNA expressions of 3subclasses of PPAR with their activators in HUVECs were not changed compared w ith controls.Conclusion.HUVECs express PPARs.PPARs activators may increase PAI-1expression in ECs,but the underlying mechanism remains uncle ar.Although PPARs expression was not enhanced after stimulated by their activators in ECs,the role of functionally active PPARs in regulating PA I-1expression in ECs needs to be further investigated by using transient gen e transfection assay.

Peroxisome proliferator-activated receptor α,a potential therapeutic target for alcoholic liver disease

Alcoholic liver injury represents a progressive process with a range of consequences including hepatic steatosis, steatohepatitis, liver fibrosis, cirrhosis, and hepatocellular carcinoma. Targeting key molecular regulators involved in the development of alcoholic liver injury may be of great value in the prevention of liver injury. Peroxisome proliferator-activated receptor &#x003b1; (PPAR&#x003b1;) plays a pivotal role in modulation of hepatic lipid metabolism, oxidative stress, inflammatory response and fibrogenesis. As such, PPAR&#x003b1; may be a potential therapeutic target for the treatment of alcoholic liver disease.

Effect of ligand of peroxisome proliferator-activated receptor γ on the biological characters of hepatic stellate cells

AIM： To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma （PPARy）, on the expression of PPARy in hepatic stellate cells （HSCs） and on the biological characteristics of HSCs. METHODS： The activated HSCs were divided into three groups： control group, 3 μmol/L rosiglitazone group, and 10 μmol/L rosiglitazone group. The expression of PPARγ, α-smooth muscle actin （α-SMA）, and type Ⅰ and Ⅲ collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium （MTT） colodmetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS： The expression of PPARγ at mRNA and protein level markedly increased in HSCs of 10 μmol/L rosiglitazone group （tvalue was 10.870 and 4.627 respectively, P〈0.01 in both）. The proliferation of HSCs in 10 μmol/L rosiglitazone group decreased significantly （t = 5.542, P〈0.01）, α-SMA expression level and type Ⅰ collagen synthesis ability were also reduced VS controls （tvalue = 10.256 and 14.627 respectively, P〈0.01 in both）. The apoptotic rate of HSCs significantly increased in 10 μmol/L rosiglitazone group vs control （X^2= 16.682, P〈0.01）. CONCLUSION： By increasing expression of PPARγ in activated HSCs, rosiglitazone, an agonist of PPARγ, decreases α-SNA expression and type Ⅰ collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.

丹酚酸B通过SIRT1/PGC-1α通路对Aβ_(1-42)干预N2A细胞保护作用研究

目的观察沉默信息调节因子2相关酶1(SIRT1)/过氧化物酶体增殖物激活受体γ共激活因子1α(PGC-1α)的表达及检测活性氧(ROS)、丙二醛(MDA)、超氧化物歧化酶(SOD)含量和线粒体膜电势,探讨丹酚酸B(SalB)减轻β淀粉样多肽1-42(Aβ1-42)干预小鼠来源神经瘤母细胞(N2A)后氧化应激损伤的作用及机制。方法使用10μM Aβ1-42寡聚体干预N2A细胞构建阿尔茨海默病(AD)细胞模型,使用40μM SalB干预细胞为对照组,模型组和SalB干预组。使用MTT法检测不同实验组细胞活力;DCFH-DA染色测定实验组细胞内ROS水平;ELISA法检测SOD,MDA水平;Western blot法和RTPCR法分别检测不同实验组SIRT1、PGC-1α蛋白和mRNA水平。结果与Aβ干预N2A细胞构建的模型组相比,SalB组处理后的模型组细胞活力显著升高(P<0.001),SalB组细胞中ROS水平显著下降(P<0.01),SOD水平显著上升(P<0.001),MDA生成显著减少(P<0.05),有效恢复线粒体膜电势(P<0.05)。另外,SalB处理后模型组细胞的SIRT1、PGC-1α蛋白和mRNA水平均升高。结论SalB可以显著降低Aβ干预N2A细胞后诱导的氧化应激反应,减少ROS产生及下调MDA水平,上调SOD水平,该神经保护作用可能与上调SIRT1/PGC-1α通路相关。

白藜芦醇通过SIRT1/PGC-1α影响牛肌管细胞线粒体生物发生和肌纤维类型转化

以牛肌管细胞为研究对象,通过添加白藜芦醇探究其对牛肌管细胞肌纤维类型转化的影响及其作用机制。通过噻唑蓝法和比色法对细胞活力和相关代谢酶活力进行测定,对成肌调节因子、肌球蛋白重链(myosin heavy chains,MyHCs)以及线粒体生物发生相关分子的基因和蛋白表达量进行测定。结果表明,白藜芦醇处理显著提高了Myf5、Myf6、MyoG和MyoD的基因表达水平(P<0.05),促进了牛肌管细胞分化。白藜芦醇处理显著提高了慢肌纤维蛋白(slow MyHC)的表达,降低了快肌纤维蛋白(fast MyHC)表达,同时上调了MyHC I和MyHC IIa基因表达水平,下调了MyHC IIx和MyHC IIb基因表达水平(P<0.05)。白藜芦醇还能显著提高牛肌管细胞中的琥珀酸脱氢酶和苹果酸脱氢酶活性,降低乳酸脱氢酶活性(P<0.05),此外,白藜芦醇显著提高了沉默信息调节因子1(silent information regulator 1,SIRT1)、过氧化物酶体增殖物激活受体γ共激活因子1α(peroxisome proliferator-activated receptor-gamma coactivator-1α,PGC-1α)、核呼吸因子(nucleus respiratory factors,NRF)-1、线粒体转录因子A(mitochondrial transcription factor A,TFAM)的基因和蛋白表达水平(P<0.05)。添加SIRT1抑制剂6-氯-2,3,4,9-四氢-1H-咔唑-1-甲酰胺(1H-carbazole-1-carboxam,EX527)后,显著削弱了白藜芦醇诱导的肌纤维类型转化(P<0.05),白藜芦醇对SIRT1、PGC-1α、NRF-1和TFAM的基因和蛋白表达的促进作用被EX527显著削弱(P<0.05)。综上所述,白藜芦醇通过激活SIRT1/PGC-1α信号通路促进线粒体生物发生,进而促进牛肌管肌纤维类型的转化。

Association between peroxisome proliferator-activated receptor-γ coactivator-1α gene polymorphisms and type 2 diabetes in southern Chinese population:role of altered interaction with myocyte enhancer factor 2C

Background Some single nucleotide polymorphisms （SNPs） in the peroxisome proliferator-activated receptor-y coactivator （PGC）-1α gene have been reported to be associated with type 2 diabetes in different populations, and studies on Chinese patients yielded controversial results. The objective of this case-control study was to explore the relationship between SNPs of PGC-1α and type 2 diabetes in the southern Chinese population and to determine whether the common variants： Gly482Ser and Thr394Thr, in the PGC-1α gene have any impacts on interaction with myocyte enhancer factor （MEF） 2C. Methods The SNPs in all exons of the PGC-1α gene was investigated in 50 type 2 diabetic patients using polymerase chain reaction-single strand conformational polymorphism （PCR-SSCP） and direct sequencing. Thereafter, 263 type 2 diabetic patients and 282 healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP）. A bacterial two-hybrid system and site-directed mutagenesis were used to investigate whether Gly482Ser and Thr394Thr variants in the PGC-1α gene alter the interaction with MEF2C. Results Three frequent SNPs （Thr394Thr, Gly482Ser and Thr528Thr） were found in exons of the PGC-1α gene. Only the Gly482Ser variant had a different distribution between diabetic patients and healthy subjects, with the 482Ser allele more frequent in patients than in controls （40.1% vs 29.3%, P〈0.01）. Even in controls, the 482Ser（A） carriers were more likely to have higher levels of total cholesterol and low-density lipoprotein cholesterol than the 482Gly（G） carriers. The 394A-482G-528A haplotype was associated with protection from diabetes, while the 394A-482A-528A was associated with the susceptibility to diabetes. The bacterial two-hybrid system and site-directed mutagenesis revealed that the 482Ser variant was less efficient than the 482Gly variant to interact with MEF2C, whereas the 394Thr （A） had a synergic effect on the interaction between 482Ser variant and MEF2C. Conclusions The results suggested that the 482Ser variant of PGC-1α conferred the susceptibility to type 2 diabetes in the southern Chinese population. The underlying mechanism may be attributable, at least in part, to the altered interaction between the different variants （Gly482Ser, Thr394Thr） in the PGC-1α gene and MEF2C.

基于网络药理学和SIRT1/PGC-1α信号通路探究青光安Ⅱ号方的视神经保护作用

目的基于网络药理学和实验研究探讨青光安Ⅱ号方对青光眼视神经的保护作用机制。方法通过TCMSP数据库筛选青光安Ⅱ号方成分靶点,在GeneCards、Disgenet、CTD数据库挖掘青光眼相关靶点,进而筛选青光安Ⅱ号方作用于青光眼的靶点;制作蛋白质-蛋白质相互作用(protein-protein interaction,PPI)网络取其交集,并通过GO分析和KEGG富集分析。建立自发性慢性高眼压DBA/2J青光眼小鼠模型,将C57BL/6J小鼠设置为空白组(等体积蒸馏水),DBA/2J小鼠随机分为模型组(等体积蒸馏水)、益脉康组[0.31 g/(kg·d)]、青光安Ⅱ号方低浓度组[0.85 g/(kg·d)]、青光安Ⅱ号方中浓度组[1.7 g/(kg·d)]、青光安Ⅱ号方高浓度组[3.4 g/(kg·d)],每组8只,每日灌胃1次。干预4周后,触式眼压笔监测小鼠眼压;HE染色观察小鼠视网膜形态结构;Western blot检测沉默信息调节因子-1(silent information regulator type-1,SIRT1)、过氧化物酶体增殖物激活受体γ共激活因子-1α(peroxisome proliferationactivated receptor-γ-coactivator 1α,PGC-1α)的蛋白表达水平;qRT-PCR检测SIRT1、PGC-1α的mRNA表达水平。结果从青光安Ⅱ号方共筛选得到101个活性成分和245个相关靶点,2412个青光眼疾病相关基因靶点;药物-活性成分-靶点相互作用最强的5个靶点分别是前列腺素内过氧化物合成酶2、核受体共激活因子2、胃蛋白酶原Ⅱ、前列腺素内过氧化物合成酶1以及过氧化物酶体增殖物激活受体γ(peroxisome proliferative activated receptor gamma,PPARG);PPI网络显示较强的靶点是SIRT1、PPARG;GO分析和KEGG富集分析得到细胞衰老、IL-17等信号通路。与给药前相比,给药后用药组眼压显著降低(P<0.01)。给药后,与空白组相比,模型组眼压显著升高(P<0.01),视网膜中SIRT1、PGC-1αmRNA表达量和蛋白表达量均显著降低(P<0.01);与模型组相比,用药组眼压显著降低(P<0.01),SIRT1、PGC-1αmRNA表达量和蛋白表达量均显著升高(P<0.01)。与益脉康组和青光安Ⅱ号方低浓度组相比,青光安Ⅱ号方中、高浓度组SIRT1、PGC-1αmRNA表达量和SIRT1蛋白表达量显著升高(P<0.01);与青光安Ⅱ号方低浓度组相比,青光安Ⅱ号方高浓度组PGC-1α蛋白表达量均显著上升(P<0.01)。与青光安Ⅱ号方中浓度组相比,青光安Ⅱ号方高浓度组PGC-1αm RNA表达量和蛋白表达量显著升高(P<0.01)。结论青光安Ⅱ号方可有效调控SIRT1/PGC-1α信号通路,抑制RGC的丢失,主要在氧化应激、细胞衰老等方面对青光眼视神经发挥保护作用。

Activation of G-protein-coupled receptor 39 reduces neuropathic pain in a rat model

Activated G-protein-coupled receptor 39(GPR39)has been shown to attenuate inflammation by interacting with sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γcoactivator 1α(PGC-1α).However,whether GPR39 attenuates neuropathic pain remains unclear.In this study,we established a Sprague-Dawley rat model of spared nerve injury-induced neuropathic pain and found that GPR39 expression was significantly decreased in neurons and microglia in the spinal dorsal horn compared with sham-operated rats.Intrathecal injection of TC-G 1008,a specific agonist of GPR39,significantly alleviated mechanical allodynia in the rats with spared nerve injury,improved spinal cord mitochondrial biogenesis,and alleviated neuroinflammation.These changes were abolished by GPR39 small interfering RNA(siRNA),Ex-527(SIRT1 inhibitor),and PGC-1αsiRNA.Taken together,these findings show that GPR39 activation ameliorates mechanical allodynia by activating the SIRT1/PGC-1αpathway in rats with spared nerve injury.

Down-regulated expressions of PPAR_γ and its coactivator PGC-1 are related to gastric carcinogenesis and Lauren's classification in gastric carcinoma

Objective： To explore the relationship between peroxisome proliferator activated receptor-gamma （PPARγ） and peroxisome proliferator-activated receptor-gamma coactivator-1 （PGC-1） expression in gastric carcinoma （GC）, and analyze their correlations with clinicopathological features and clinical outcomes of patients. Methods：The two-step immunohistochemical method was used to detect the expression of PPARγ and PGC-1 in 179 cases of GC, and 108 cases of matched normal gastric mucosa. Besides, 16 cases of fresh GC specimens and corresponding normal gastric mucosa were detected for PGC-1 expression with Western blotting. Results： The positive rates of PPART and PGC-1 expression were significantly lower in GC （54.75%, 49.16%） than in normal gastric mucosa （70.37%, 71.30%）, respectively （P〈0.05）. The decreased expression of PGC-1 in GC was confirmed ha our Western blot analysis （P=0.004）. PPAR7 and PGC-1 expressions were related to Lauren＇s types ofGC （P〈0.05）. Positive correlation was found between PPART and PGC-1 expression in GC （rk=0.422, P〈0.001）. The survival time of PPART negative and positive patients was 36.6±3.0 vs. 38.5_＋2.7 months, and no statistical difference was found between the 5-year survival rates of two groups （34.4% vs. 44.1%, P=0.522, log-rank test）; the survival time of PGC-1 negative and positive patients was 36.2±2.8 vs. 39.9±2.9 months, while no statistical difference was found between the 5-year survival rates of the two groups （32.0% vs. 48.2%, P=0.462, log-rank test） Conclusions＇. Decreased expression of PPARγand PGC-1 in GC was related to the Lauren＇s classification. Their expressions in GC were positively correlated, indicating that their fimctions in gastric carcinogenesis may be closely related.

Down-regulation of peroxisome proliferator-activated receptor γ coactivator-1α expression in fatty acid-induced pancreatic betacell apoptosis involves nuclear factor-κB pathway

Background Pancreatic beta-cell apoptosis induced by lipotoxicity, to a large extent, contributes to the progression of type 2 diabetes. To investigate the mechanism of free fatty acid induced apoptosis, we aimed to study the effects of palmitic acid （PA） on the apoptosis and peroxisome proliferator-activated receptor y coactivator-1α （PGC-1α） expression in βTC3 cells as well as the possible role of nuclear factor-KB （NF-KB） in this process. Methods Hoechst 33258 was used to detect βTC3 cell apoptosis, which was induced by PA stimulation for 12 hours. PGC-1α expression was analyzed by reverse transcription polymerase chain reaction, IκB kinase β （IKKβ）, IκBα NF-KB-inducing kinase （NIK） and ReI-B expressions were analyzed by Western blotting. MGβ2 was employed to block the endogenous IκBαdegradation before PA administration, and then its effect on PA-inducing cell apoptosis and PGC-1α mRNA expression was analyzed. Results Significant increased cell apoptosis was found at the concentration of 0.5 mmol/L and 1.0 mmol/L PA administration. PA （0.5 mmol/L） could extensively reduced the expression of PGC-1α mRNA. After exposing βTC3 cells to 0.5 mmol/L PA for different time periods （0, 4, 6, 8, 10 and 12 hours）, IKKβ protein expression increased while IκBα NIK and ReI-B protein expression declined in a time-dependent manner. Pretreatment with MGβ2 to inhibit the degradation of IκBα partially prevented the down-regulation of PGC-1α mRNA expression after 12-hour PA treatment in accordance with the decrease of PA induced apoptosis. Conclusions NF-KB canonical pathway was activated in PA-mediated βTC3 cell apoptosis, whereas non-canonical pathway was inhibited. Reduced PGC-1α expression by PA in βTC3 cells could involve the activation of canonical NF-KB pathway, so as to deteriorate the PA induced apoptosis.

Sestrin1参与调控小鼠肝脏细胞糖异生

目的研究应激诱导蛋白1(SESN1)在小鼠肝脏糖异生途径中的作用及调节机制。方法RT-qPCR检测SESN1在C57BL/6J小鼠禁食条件下肝脏组织以及用佛司可林(Fsk)与地塞米松(Dex)处理的原代肝细胞中的mRNA表达水平。通过质粒转染HepG2细胞,RT-qPCR检测SESN1过表达对糖异生相关基因PGC-1α,PEPCK,G6Pase的mRNA表达水平的影响。利用双荧光素酶报告系统研究SESN1在HepG2细胞中对PGC-1α的启动子活性的影响。在HepG2细胞中,通过过表达SESN1同时抑制SIRT1表达检测SESN1对PGC-1α去乙酰化状态的影响;通过敲低SIRT1表达检测其是否介导了SESN1诱导糖异生相关基因mRNA水平的变化。结果SESN1在饥饿的C57BL/6J小鼠肝脏组织和佛司可林(Fsk)和地塞米松(Dex)处理的原代肝细胞中的mRNA表达水平显著升高(P<0.001)。在HepG2细胞中过表达SESN1促进了PGC-1α,PEPCK,G6Pase的mRNA表达水平(P<0.001)并促进PGC-1α的启动子活性(P<0.001)。SESN1的过表达降低了原代肝细胞中PGC-1α的乙酰化水平,利用Sirt家族抑制剂NAM和shRNA腺病毒分别干扰SIRT1表达,均拮抗了SESN1对PGC-1α的去乙酰化作,同时SIRT1诱导的PGC-1α,PEPCK和G6Pase的表达也明显受损(P<0.0001)。结论SESN1参与调控小鼠肝脏细胞糖异生,可能依赖于SIRT1。

Effect of Peroxisome Proliferator-Activated Receptor-γ Coactivator-1 Alpha Variants on Spontaneous Clearance and Fibrosis Progression during Hepatitis C Virus Infection in Moroccan Patients

Hepatitis C virus(HCV)is still one of the main causes of liver disease worldwide.Metabolic disorders,including nonalcoholic fatty liver disease(NAFLD),induced by HCV have been shown to accelerate the progression of fibrosis to cirrhosis and to increase the risk of hepatocellular carcinoma.An optimal peroxisome proliferator-activated receptor gamma coactivator 1-alpha(PPARGC1A)activity is crucial to prevent NAFLD installation.The present study aims to investigate the associations between two common PPARGC1A polymorphisms(rs8192678 and rs12640088)and the outcomes of HCV infection in a North African context.A series of 592 consecutive Moroccan subjects,including 292 patients with chronic hepatitis C(CHC),100 resolvers and 200 healthy controls were genotyped using a TaqMan allelic discrimination assay.PPARGC1A variations at rs8192678 and rs12640088 were not associated with spontaneous clearance of HCV infection(adjusted ORs=0.76 and 0.79 respectively,P[0.05,for both).Furthermore,multivariable logistic regression analysis showed that both SNPs were not associated with fibrosis progression(OR=0.71;95%CI 0.20–2.49;P=0.739;OR=1.28;95%CI 0.25–6.54;P=0.512,respectively).We conclude that,in the genetic context of South Mediterranean patients,rs8192678 and rs12640088 polymorphisms of PPARGC1 A are neither associated with spontaneous clearance nor with disease progression in individuals infected with HCV.

多囊卵巢综合征病人血清Ⅲ型纤连蛋白域蛋白5、过氧化物酶体增殖物激活受体γ辅助激活因子-1α水平与胰岛素抵抗的关系

目的探究多囊卵巢综合征(PCOS)病人血清Ⅲ型纤连蛋白域蛋白5(FNDC5)、过氧化物酶体增殖物激活受体γ辅助激活因子-1α(PGC-1α)表达水平与胰岛素抵抗的关系。方法选取2017年1月至2021年12月在重庆松山医院接受治疗的118例PCOS病人为PCOS组,另选取与PCOS病人年龄、身体质量指数(BMI)、腰臀比相匹配的同期健康体检者94例作为对照组。酶联免疫吸附测定(ELISA)检测两组血清FNDC5、PGC-1α表达水平;全自动生化分析仪检测空腹胰岛素(FINS)、空腹血糖(FBG)水平,并计算胰岛素抵抗相关指标胰岛β细胞功能指数(HOMA-β)和胰岛素抵抗指数(HOMA-IR);Pearson相关性分析研究病人血清FNDC5、PGC-1α水平与胰岛素抵抗相关指标之间的关系。结果与对照组相比,PCOS组FBG、FINS、三酰甘油(TG)、HOMA-β、HOMA-IR显著升高(P<0.05);与对照组相比,PCOS组FNDC5[(18.46±2.76)μg/L比(30.25±5.87)μg/L]、PGC-1α[(1.87±0.45)μg/L比(4.91±1.34)μg/L]表达水平显著降低(P<0.05)。Pearson相关性分析结果显示,PCOS病人血清FNDC5、PGC-1α水平均与FBG、FINS、HOMA-β、HOMA-IR呈显著负相关(P<0.05)。结论PCOS病人血清FNDC5、PGC-1α表达水平降低,与胰岛素抵抗存在负相关。

田蓟苷调节AMPK/SIRT1/PGC1α信号通路对脑出血大鼠认知功能和神经元损伤的影响

目的:探讨田蓟苷(TIL)对脑出血(ICH)大鼠认知功能、神经元损伤及腺苷酸激活蛋白激酶(AMPK)/沉默调节蛋白1(SIRT1)/过氧化物酶体增殖活化受体γ辅助活化因子1α(PGC1α)信号通路的影响。方法:采用Ⅳ型胶原酶注射法构建ICH大鼠模型,将造模成功的ICH大鼠随机分为模型组(ICH组)、TIL组(16 mg/kg)、AMPK抑制剂组(Compound C组,250μg/kg)、TIL+AMPK抑制剂组(TIL+Compound C组),另设假手术组(Sham组),每组12只。采用改良的Garcia JH法、Morris水迷宫实验和敞箱实验评价大鼠的神经功能和认知功能;苏木素-伊红(HE)和脱氧核糖核苷酸末端转移酶介导的缺口末端标记(TUNEL)法行脑组织病理学和神经元凋亡观察;蛋白质印迹法(Western Blot)检测AMPK/SIRT1/PGC1α通路蛋白表达。结果:与Sham组相比,ICH组大鼠脑组织出现细胞核皱缩、排列紊乱等损伤,神经功能评分、穿越平台次数、垂直活动得分和水平活动得分、磷酸化AMPK(p-AMPK)/AMPK、SIRT1、PGC1α蛋白水平均明显下降(P<0.05),找寻平台时间、神经元凋亡率、半胱氨酸蛋白酶-3(Caspase-3)、B淋巴细胞瘤-2(Bcl-2)蛋白表达水平均明显增加(P<0.05);与ICH组相比,TIL组大鼠脑组织损伤减轻,神经功能评分、穿越平台次数、垂直活动得分和水平活动得分、p-AMPK/AMPK、SIRT1、PGC1α蛋白水平均明显增加(P<0.05),找寻平台时间、神经元凋亡率、Caspase-3、Bcl-2蛋白表达水平均明显降低(P<0.05);而Compound C组大鼠以上指标呈现相反的趋势。且TIL对ICH大鼠脑组织及认知功能的保护作用均被AMPK抑制剂Compound C减弱(P<0.05)。结论:TIL可能通过激活AMPK/SIRT1/PGC1α通路,改善ICH大鼠认知功能,减轻神经元损伤。

芍药苷调节SIRT1/PGC-1α/Nrf2信号通路对过氧化氢诱导皮肤成纤维细胞氧化应激损伤的影响

目的:探讨芍药苷(PF)调节沉默信息调节因子2同系物1(SIRT1)/氧化物酶体增殖物激活受体γ共激活剂-1α(PGC-1α)/核因子E2相关因子2(Nrf2)信号通路对过氧化氢(H_(2)O_(2))诱导皮肤成纤维细胞(HSF)氧化应激损伤的影响。方法:以HSF细胞为研究对象,将其分为Control组、H_(2)O_(2)组、L-PF、M-PF、H-PF组、PF+EX527组;CCK-8检测HSF细胞增殖;β-半乳糖苷酶染色法检测HSF细胞衰老;流式细胞仪检测HSF细胞凋亡;ELISA法检测HSF细胞中ROS、SOD、GSH、MDA的表达;WB检测HSF细胞中SIRT1、PGC-1α、Nrf2蛋白表达。结果:H_(2)O_(2)组HSF细胞的存活率、SOD、GSH、SIRT1、PGC-1α、Nrf2表达低于Control组,衰老细胞比例、凋亡率、ROS、MDA表达高于Control组(P<0.05);与H_(2)O_(2)组比较,L-PF组、M-PF组、H-PF组存活率、SOD、GSH、SIRT1、PGC-1α、Nrf2表达升高,衰老细胞比例、凋亡率、ROS、MDA表达降低(P<0.05);PF+EX527组存活率、SOD、GSH、SIRT1、PGC-1α、Nrf2表达低于H-PF组,衰老细胞比例、凋亡率、ROS、MDA表达高于H-PF组(P<0.05)。结论:PF可以抑制H_(2)O_(2)诱导的HSF细胞氧化应激损伤,其机制可能是激活SIRT1/PGC-1α/Nrf2信号通路实现的。

Activation of peroxisome proliferator-activated receptor α in human endothelial cells increases plasminogen activator inhibitor type-1 expression

Objective To investigate the effect of peroxisome proliferator-activated receptors (PPARs) activators on plasminogen activator inhibitor 1 (PAI-1) expression in human umbilical vein endothelial cells and elucidate a possible mechanism. Methods Human umbilical vein endothelial cells (HUVECs) were obtained from normal fetus, and cultured conventionally. Then the HUVEC were exposed to fatty acids and prostaglandin J 2 in varying concentrations with fresh media. RT-PCR and ELISA were used to determine the expression of PPAR and PAI-1 in HUVECs. Transient co-transfection of PAI-1 promoter and PPARα gene or PPARγ gene to ECV304 was performed.Results PPARα, PPARδ and PPARγ mRNA in HUVECs were detected by RT-PCR. Treatment of HUVECs with PPARα and PPARγ activators-linolenic acid, linoleic acid, oleic acid and prostaglandin J 2, but not with stearic acid could augment PAI-I mRNA expression and protein secretion in a concentration-dependent manner. Proportional induction of PAI-1 promoter activity was observed through increasing amounts of PPARα DNA in HUVECs through a transient gene transfection assay, although the mRNA expression of the 3 subtypes of PPAR with their activators were not changed compared with controls.Conclusions HUVECs express PPARs. PPARs activators may increase PAI-1 expression in endothelial cells (EC). Although PPARs expression was not enhanced after being stimulated by their activators in EC, the functionally active PPARα is probably involved in regulating PAI-1 expression in EC.