Cytochrome P4501B1 and basal liver PPARa activity

细胞色素 P4501B1 和基础肝脏 PPARa 活性

• 批准号: 8822861
• 负责人: COLIN ROBERT JEFCOATE
• 金额: $ 32.38万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8822861
• 关键词: ADD-1 protein; Address; Adhesions; Adipocytes; Adipose tissue; Adult; Affect; Agonist; Alleles; Amino Acids; Binding; Biological Factors; Blood capillaries; Breeding; CYP1B1 gene; Carbohydrates; Cells; Clinical Research; Complex; Cytochrome P450; Data; Development; Developmental Process; Diabetes Mellitus; Diet; Dietary Fats; Discontinuous Capillary; Effectiveness; Embryo; Embryonic Development; Endothelial Cells; Endothelium; Event; Exhibits; FGF21 gene; Fat-Restricted Diet; Fatty Acids; Fatty Liver; Fatty acid glycerol esters; Fetal Liver; Fetus; Fibroblasts; Gene Cluster; Gene Expression; Generations; Genes; Glaucoma; Glycogen; Goals; Hepatic; Hepatocyte; Human; In Vitro; Infiltration; Intervention; Lead; Ligands; Link; Liver; Liver neoplasms; Mass Spectrum Analysis; Measures; Mediating; Metabolism; Mitochondria; Morphogenesis; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Oxidative Stress; PPAR gamma; Pathway interactions; Peripheral; Peroxisome Proliferator-Activated Receptors; Regulation; Research; Role; Serum; Serum Markers; Signal Transduction; Site; Source; Stromal Cells; Tamoxifen; Testing; Therapeutic; Time; Tissues; Variant; Weaning; adenoma; angiogenesis; base; capillary; cell type; cytokine; endonuclease; fatty acid metabolism; fatty acid oxidation; feeding; flavanoid; hormone regulation; imprint; improved; in utero; in vivo; inhibitor/antagonist; insulin sensitivity; lipid biosynthesis; liquid chromatography mass spectrometry; liver metabolism; macrophage; metabolomics; non-alcoholic; oxidation; promoter; response; stellate cell

DESCRIPTION (provided by applicant): Cytochrome P450 1b1 (Cyp1b1) participates in embryogenesis and is expressed in endothelia, fibroblasts and adipocytes. Genes involved in liver fatty acid metabolism are remarkably affected by deletion of Cyp1b1 in mice, despite only minimal expression in hepatocytes. Two gene clusters, distinguished by responses to dietary fat, are both suppressed by Cyp1b1 deletion and regulated by PPARα Preliminary data that indicates that Cyp1b1 participates in the generation of endogenous PPARα ligands will be explored further. Cyp1b1 deletion also suppresses diet-induced obesity and non-alcoholic hepatic steatosis. The increased liver fatty acid metabolism may be associated with decreased oxidative stress, as indicated by improved insulin sensitivity. Cyp1b1 may, therefore, be an unexpected contributor to Type 2 diabetes. Many dietary flavanoids are potent inhibitors of Cyp1b1. Select Cyp1b1 inhibitors, including natural compounds, may have therapeutic value for diabetes. Human Cyp1b1 suppression also enhances liver adenomas, consistent with a role in developmental processes. The proposed research compares the liver gene expression, metabolism responses and adiposity changes in WT and Cyp1b1-ko mice administered low fat/high carbohydrate or high fat/low carbohydrate diets. The goal is to determine how hepatocytes can be indirectly affected by Cyp1b1 metabolism in other cell types, particularly the endothelia of liver sinusoids and adipose tissue. The expression of Cyp1b1 in non-parenchymal liver cells and in fetal liver will be characterized. In order to define the site and timing of Cypb1 intervention, we have introduced a Floxed Cyp1b1 allele into mice. This will ultimately provide the means for controlled Cyp1b1 deletions in mice. We will use this defining set of liver and adipose responses to determine the effectiveness of Cyp1b1 deletions specifically targeted to endothelia by Tie2-Cre. We have shown that Cyp1b1 deletion affects the functions of endothelial cells and suppresses angiogenesis in vivo. Cyp1b1 deletion may cause these adult changes through active participation of Cyp1b1 in the fetal liver development that imprints adult liver regulation. Cre-targeting of Floxed Cyp1b1 will be activated through a tamoxifen-dependent promoter at selected times during development, in order to test whether this early expression contributes to the general deletion effects. Metabolomic studies using 2D-NMR and mass spectrometry analyses on, respectively, liver and serum extracts will focus on establishing that Cyp1b1 deletion increases mitochondrial fatty acid oxidation and glycogen synthesis, while lowering oxidative stress. The roles of PPARα and PPARγ loss in these liver gene changes of Cyp1b1-ko mice will be tested by comparisons to effects of deleting these PPAR genes in mouse liver. Serum markers applicable to clinical studies will be used in probing these liver changes.

描述（由申请人提供）：细胞色素P450 1b1 （Cyp1b1）参与胚胎发生，并在内皮细胞、成纤维细胞和脂肪细胞中表达。在小鼠中，Cyp1b1基因的缺失显著影响了肝脏脂肪酸代谢的相关基因，尽管在肝细胞中只有极少的表达。两个基因簇，通过对膳食脂肪的反应来区分，都受到Cyp1b1缺失的抑制和PPARα的调节，初步数据表明Cyp1b1参与内源性PPARα配体的产生，将进一步探索。Cyp1b1缺失也抑制饮食引起的肥胖和非酒精性肝脂肪变性。肝脏脂肪酸代谢的增加可能与氧化应激的减少有关，正如胰岛素敏感性的改善所表明的那样。因此，Cyp1b1可能是2型糖尿病的一个意想不到的因素。许多膳食类黄酮是Cyp1b1的有效抑制剂。选择Cyp1b1抑制剂，包括天然化合物，可能对糖尿病有治疗价值。人类Cyp1b1抑制也增强肝腺瘤，与发育过程中的作用一致。本研究比较了低脂/高碳水化合物或高脂/低碳水化合物饮食对WT和Cyp1b1-ko小鼠肝脏基因表达、代谢反应和肥胖变化的影响。目的是确定肝细胞如何间接受到其他细胞类型Cyp1b1代谢的影响，特别是肝窦内皮和脂肪组织。Cyp1b1在非实质肝细胞和胎儿肝中的表达将被表征。为了确定Cypb1干预的位点和时间，我们将一个Floxed Cyp1b1等位基因引入小鼠。这将最终为控制小鼠Cyp1b1缺失提供手段。我们将使用这组肝脏和脂肪反应来确定Tie2-Cre特异性靶向内皮细胞的Cyp1b1缺失的有效性。我们已经证明Cyp1b1缺失会影响内皮细胞的功能并抑制体内血管生成。Cyp1b1缺失可能通过Cyp1b1在胎儿肝脏发育中的积极参与导致这些成人变化，而胎儿肝脏发育印记着成人肝脏的调节。Floxed Cyp1b1的cfr靶向将在发育过程中的选定时间通过他莫昔芬依赖性启动子激活，以测试这种早期表达是否有助于一般缺失效应。利用2D-NMR和质谱分析分别对肝脏和血清提取物进行代谢组学研究，将重点确定Cyp1b1缺失增加线粒体脂肪酸氧化和糖原合成，同时降低氧化应激。PPARα和PPARγ缺失在Cyp1b1-ko小鼠肝脏基因变化中的作用将通过与小鼠肝脏中PPAR基因缺失的影响进行比较来验证。适用于临床研究的血清标记物将用于探测这些肝脏变化。