Objective: Expression characteristics of C-reactive protein (CRP) for the omega-6/omega-3 polyunsaturated fatty acid (PUFA) ratios have not been evaluated in the well-qualified experimental atherosclerotic mouse model. This work focused on characteristics of CRP expression in the liver of apolipoprotein E-null (apoE(-/-)) mice influenced by omega-6/omega-3 PUFA ratios.Methods: Varying ratios of omega-6/omega-3 PUFAs (group 1, 1.28; group 2, 5.03; group 3, 9.98; and group 4, 68.26, respectively) on hepatic and aortic CRP expressions were assessed in male apoE(-/-) mice fed a diet containing 5% (w/w) experimental fat for 6 wk. Hepatic peroxisome proliferator-activated receptor-gamma mRNA abundance, hepatic interleukin (IL)-6 protein level, atherosclerotic lesions, and serum cytokines including IL-1 beta, IL-6, and tumor necrosis factor-alpha were examined.Results: As the dietary ratio of omega-6/omega-3 fatty acids ascended, so did the expression of hepatic and aortic CRP and hepatic IL-6 protein. However, peroxisome proliferator-activated receptor-gamma mRNA level had a tendency to decrease. Serum IL-1 beta, IL-6, and tumor necrosis factor-alpha levels did not show a statistical difference among the mice fed the four ratios of the omega-6/omega-3 PUFA diet. The group 4 mice developed a significant increase in atherosclerotic lesions compared with the other groups.Conclusion: The results indicated that low ratios of omega-6/omega-3 PUFAs (1.28-9.98) downregulated the hepatic and aortic CRP expressions and reduced aortic en face lesions in apoE(-/-) mice compared with the high ratio of the omega-6/omega-3 PUFA diet. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.

内质网是一个动态的膜性细胞器,具有多种功能,包括蛋白质的合成、修饰、折叠、类固醇、脂质和糖原的合成以及钙的储存与钙稳态的维持等[1].内质网含有大量的伴侣蛋白、糖基化酶以及氧化还原酶,为新生肽链的折叠提供了优化的环境,同时内质网质量控制系统能通过内质网相关性降解(endo-plasmic reticulum associated degradation,ERAD)过程,降解非正确折叠或修饰的中间产物.

目的:探讨内质网应激(ERS)在2型糖尿病(T2DM)小鼠脂肪肝发生中的作用机制.方法:应用实时定量RT-PCR技术检测T2DM与非糖尿病小鼠肝脏ERS和脂代谢相关基因表达差异, 并进行血生化指标及肝脏形态学检测.结果:与同龄非T2DM小鼠相比T2DM小鼠表现为:(1)胰岛素抵抗、空腹血糖升高(30.76±4.52 vs 12.80±2.13, 14.73±2.74v s 4.61±1.12). (2)肝脏TG和F FA水平明显升高( P<0.01); 脂肪肝病变明显. (3)肝脏GRP78、XBP1、CHOP、EDEM1、GSK3β、apoB100、SREBP1c、ACCα及FAS的mRNA水平均显著上调( P<0.05). (4)血清TG、TC、LDL-C、FFA、ALT及AST显著升高( P<0.01).血清apoB100水平先升高, 后下降( P<0.05).结论:ERS参与调节肝脏脂质及apoB100的合成与代谢过程, 在T2DM小鼠脂肪肝发生过程中起着重要作用.

AIM:Dietary fatty acids affect atherogenesis, which was presumed to be partly related to HDL cholesterol (HDL-C) metabolism. The major aim of the work was to analyze various ratios of n-6/n-3 PUFA diets on HDL-C metabolism in apolipoprotein E-null (apoE(-/-)) mice, which have similar symptoms to human type III familial hyperlipoproteinemia. METHODS:Two-month-old male apoE(-/-) mice were fed four types of n-6/n-3 PUFA diet (group 1, 1.28; group 2, 5.03; group 3, 9.98 and group 4, 68.26) and control diet, respectively, for 6 weeks. With respect to serum apolipoprotein (apo) A-I concentration, lecithin-cholesterol acyltransferase (LCAT) activity and mRNA abundance of genes involved in HDL-C metabolism in the liver were analyzed. RESULTS:Group 4 diet significantly increased the plasma HDL-C and apoA-I concentrations compared with other groups. LCAT activity in serum increased with decreased ratios of n-6/n-3 PUFA. As the dietary ratio of n-6/n-3 fatty acids increased, so did mRNA levels of hepatic apoA-I, scavenger receptor B class-1 (SR-B1), LCAT, ATP binding cassette transporter A1 (ABCA1), ABCG1 and liver X receptor alpha (LXRalpha). ApoA-II mRNA level, however, had a tendency to fall. Group 4 diet increased apoA-I and ABCA1 and decreased apoA-II transcriptional levels, whereas group 1 diet decreased mRNA levels of apoA-I, LCAT, SR-B1 and ABCG1. CONCLUSION:Our data indicated that a high ratio of n-6/n-3 PUFA increased the serum HDL-C level, but did not effectively suppress atherogenesis in apoE(-/-) mice. The elevated HDL-C level is possibly due to up-regulated hepatic apoA-I and ABCA1 with suppression of apoA-Ii expression.

To investigate the effect of apolipoprotein E (apoE) on cytokine expression profile of the liver of young mice, quantitative RT-PCR (qRT-PCR) assay and cytokine antibody array for multiplex analysis of 62 cytokines have been used to analyze characteristics of expression of cytokines in the liver of 6-week-old apoE-null (apoE−/−) mice. The levels of plasma cytokines were also analyzed. The mRNA level of IL-1β, IL-2, IL-6, ICAM-1, VCAM-1, MCP-1, NF-κB (p65), IFN-γ and IκB-α were increased significantly in apoE−/− mice comparative to wild-type (WT) mice. IL-4, IL-10 and GM-CSF, however, were slightly decreased. Compared with WT, levels of 21 cytokines altered twofold or more in apoE−/− mice, including 10 cytokines increased and 11 decreased. Expression patterns of IL-1β, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ and VCAM-1 showed identical trend between cytokine antibody array and qRT-PCR analysis. Moreover, levels of IL-1β, IFN-γ and IL-6 in the plasma were elevated, while IL-4 was lightly decreased in apoE−/− mice compared to those in WT mice. These results implied that promotion of type I immune response in the liver of young apoE−/− mice due to alteration of these cytokines, and the phenotypes may be caused by the regulation of NF-κB. The inflammation and lipid metabolism dysfunction in the liver cooperated in dysfunction of the liver in young apoE−/− mice.

The significance of transcription factors PPARα, LXRα, and their responsive/target genes for the pathogenesis of atherosclerosis in apolipoprotein E and low-density lipoprotein receptor double deficient (AL) mice fed with high fat and cholesterol (HF) diet were studied. C57BL/6J wild-type (WT) mice were used as control to the AL mice. Plasma lipid metabolites and morphological atherosclerotic lesions in aortic wall were determined. Semi- and real-time quantitative RT-PCR were used to measure gene expression patterns between AL mice and the controls, which were fed with HF or normal chow diet. The results showed that in AL mice fed with HF diet, plasma lipid levels, hepatic lipid accumulation, and atherogenesis together with upregulated PPARα, LXRα, and their target genes, i.e., FAT, SCD1, FAS, Angptl3, and apoB100 significantly increased in a 12-week long feeding period. In contrast, apoAI, apoAIV, apoF, LPL, and SR-BI were decreased compared to chow-fed group. In WT mice, PPARα, LXRα, FAS, Angpt13, CPT1, apoF, ACOX1, LPL, and SR-BI were increased with HF treatment, while apoAI and apoAIV were decreased markedly. The different changes of lipid metabolism-related genes between AL and WT mice, fed with HF diet or chow diet indicated that the mechanisms of dietary effects on gene mutant mice are different from those of intact WT mice. Since lipid metabolic system defected genetically in AL mice, we suggest that the changes of PPARα, LXRα, and their target genes aggravated lipid metabolic disorder in the liver and further accelerated the development of atherosclerosis on a stress of HF diet feeding in AL mice.