Regulation of Brown Fat Development and Function by Cyclin C

细胞周期蛋白 C 对棕色脂肪发育和功能的调节

• 批准号: 10164757
• 负责人: JEFFREY E. PESSIN
• 金额: $ 54.02万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10164757
• 关键词: ATP Synthesis Pathway; Adipocytes; Adipose tissue; American; B-Lymphocytes; Binding Proteins; Brown Fat; Carbohydrates; Cell Respiration; Cells; Complex; Cyclins; Data; Defect; Development; Diabetes Mellitus; Diagnosis; Diet; Dietary Carbohydrates; Elements; Energy Metabolism; Esterification; Event; Fatty Acids; Fatty acid glycerol esters; Gene Expression; Gene Expression Profiling; Generations; Genes; Genetic Transcription; Health Care Costs; Histologic; Homeostasis; Impairment; Insulin Resistance; Knock-out; Ligands; Lipids; Lipoproteins; Liver; Maintenance; Mediating; Mediator of activation protein; Metabolic; Metabolic Diseases; Molecular; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Obesity Epidemic; Outcome; PPARG gene; Pathway interactions; Physiology; Prevalence; Process; Protein Complex Subunit; RNA Polymerase II; Regulation; Residual state; Rest; Role; Signal Transduction; Temperature; Testing; Transcriptional Activation; Transcriptional Regulation; Triglycerides; United States; adipocyte differentiation; adipokines; base; cell type; cofactor; cyclin C; dietary; in vivo; lipid biosynthesis; mature animal; mitochondrial uncoupling protein; mouse model; novel; novel strategies; obesity prevention; overexpression; programs; transcription factor; uncoupling protein 1

The Mediator complex is a multi-subunit protein complex that acts as a transcriptional cofactor by connecting a number of transcription factors to the RNA polymerase II. Cyclin C (CycC) is a highly conserved subunit of the Mediator complex, but its role in brown/beige adipocytes remains unclear. We recently identify CycC as a regulator of brown adipocyte development and function. CycC knockout in Myf5+ cells reduces but does not eliminate brown adipose tissues. The residual brown adipocytes display a marked reduction in lipid accumulation in mice maintained on the standard chow diet. Gene expression analyses revealed that CycC knockout selectively impaired the expression of ChREBP target genes including Fasn, the key gene for de novo lipogenesis. The CycC-Mediator was found to physically interact with ChREBP and the transcriptional activity of ChREBP was reduced in CycC-knockout cells. These data suggest that under high-carbohydrate dietary conditions, brown adipocyte autonomous ChREBP-dependent de novo lipogenesis may be required for lipid droplet formation. Although CycC knockout had little effect on the overall integrity of the rest of the Mediator complex, differentiation was inhibited in CycC-knockout brown preadipocytes. This was likely due to the requirement of CycC for the expression of key adipogenic genes, including Zfp423 and Pparg. Overexpression of PPARg or addition of PPARg ligands rescued the defect in CycC-knockout cells, indicating that CycC is not required for PPARg transcriptional activity, but for Pparg gene expression. The expression of Zfp423 and Pparg are regulated by the EBF transcription factors and the CycC-Mediator also physically interacts with EBF1. Based on the preliminary studies, we hypothesize that CycC in the context of the Mediator complex regulates brown/beige adipocyte development and function through two distinct mechanisms. First, the CycC-Mediator complex is required for EBF1-mediated activation of Zfp423 and Pparg genes necessary for brown/beige preadipocyte determination. Second, the CycC-Mediator complex is also required for ChREBP transcriptional activity critical for brown/beige adipocyte lipogenic gene expression necessary for cell autonomous de novo lipogenesis. To test these hypotheses, we propose two related but independent Specific Aims. Aim 1 will examine the CycC-Mediator regulation of the transcriptional activity and expression of EBF1 and EBF2 in brown/beige preadipocytes, the Mediator functions in brown/beige adipocyte development in vivo, and the context-dependent regulation of CycC on the transcription program that controls the brown/beige preadipocyte determination. Aim 2 will examine the CycC-Mediator regulation of ChREBP in brown/beige adipocytes, and histologic, metabolic and molecular outcomes of Ucp1+ cell- specific knockout of CycC or ChREBP in mouse models under various dietary and temperature conditions. The long-term objective is to understand the molecular basis for brown and beige adipocyte lineage commitment and the role of de novo lipogenesis in the physiology of brown and beige adipocyte function.

中介复合物是一种多亚基蛋白质复合物，通过将许多转录因子连接到RNA聚合酶II上，作为转录辅助因子。细胞周期蛋白C （CycC）是中介体复合体的一个高度保守的亚基，但其在棕色/米色脂肪细胞中的作用尚不清楚。我们最近发现CycC是棕色脂肪细胞发育和功能的调节因子。敲除Myf5+细胞中的CycC可减少但不消除棕色脂肪组织。残留的棕色脂肪细胞显示，在标准饮食小鼠脂质积累显著减少。基因表达分析显示，CycC敲除选择性地损害了ChREBP靶基因的表达，包括Fasn， Fasn是重新生成脂肪的关键基因。发现CycC-Mediator与ChREBP发生物理相互作用，并且在cycc敲除细胞中，ChREBP的转录活性降低。这些数据表明，在高碳水化合物饮食条件下，棕色脂肪细胞自主的依赖chrebp的新生脂肪形成可能需要脂滴形成。尽管敲除CycC对其余中介复合物的整体完整性影响不大，但敲除CycC的棕色前脂肪细胞的分化受到抑制。这可能是由于CycC需要表达关键的脂肪形成基因，包括Zfp423和Pparg。过表达PPARg或添加PPARg配体挽救了CycC敲除细胞的缺陷，这表明PPARg转录活性不需要CycC，但PPARg基因表达需要CycC。Zfp423和Pparg的表达受EBF转录因子调控，CycC-Mediator也与EBF1发生物理相互作用。基于初步研究，我们假设在中介复合物的背景下，CycC通过两种不同的机制调节棕色/米色脂肪细胞的发育和功能。首先，CycC-Mediator复合物是ebf1介导的Zfp423和Pparg基因激活所必需的，而Zfp423和Pparg基因是褐色/米色前脂肪细胞测定所必需的。其次，CycC-Mediator复合物也是ChREBP转录活性所必需的，ChREBP转录活性对于细胞自主新生脂肪生成所需的棕色/米色脂肪细胞脂质基因表达至关重要。为了验证这些假设，我们提出了两个相关但独立的具体目标。目的1将研究CycC-Mediator对棕色/米色前脂肪细胞中EBF1和EBF2转录活性和表达的调节，Mediator在体内棕色/米色脂肪细胞发育中的功能，以及CycC对控制棕色/米色前脂肪细胞决定的转录程序的上下文依赖性调节。目的2将研究CycC- mediator在棕色/米色脂肪细胞中对ChREBP的调节，以及在不同饮食和温度条件下小鼠模型中Ucp1+细胞特异性敲除CycC或ChREBP的组织学、代谢和分子结果。长期目标是了解棕色和米色脂肪细胞谱系的分子基础，以及新生脂肪生成在棕色和米色脂肪细胞功能生理学中的作用。

项目成果

The Mediator Complex and Lipid Metabolism.

• 发表时间: 2013-03
• 期刊: Journal of biochemical and pharmacological research
• 作者: Yi Zhang;Xiaoli;Xiaoping Zhao;Fajun Yang

Natural Polyphenols Inhibit Lysine-Specific Demethylase-1 in vitro.

• 发表时间: 2013-03
• 期刊: Journal of biochemical and pharmacological research
• 作者: A. Abdulla;Xiaoping Zhao;Fajun Yang

Inhibition of SREBP transcriptional activity by a boron-containing compound improves lipid homeostasis in diet-induced obesity.

含硼的化合物对SREBP转录活性的抑制可改善饮食诱导的肥胖症中的脂质稳态。

• DOI: 10.2337/db13-0835
• 发表时间: 2014-07
• 期刊: Diabetes
• 影响因子: 7.7
• 作者: Zhao X;Xiaoli;Zong H;Abdulla A;Yang ES;Wang Q;Ji JY;Pessin JE;Das BC;Yang F
• 通讯作者: Yang F

Mediating lipid biosynthesis: implications for cardiovascular disease.

• DOI: 10.1016/j.tcm.2013.03.002
• 发表时间: 2013-10
• 期刊: Trends in cardiovascular medicine
• 影响因子: 9.3
• 作者: Xiaoli;Yang F
• 通讯作者: Yang F

CDK8-Cyclin C Mediates Nutritional Regulation of Developmental Transitions through the Ecdysone Receptor in Drosophila.

• DOI: 10.1371/journal.pbio.1002207
• 发表时间: 2015-07
• 期刊: PLoS biology
• 影响因子: 9.8
• 作者: Xie XJ;Hsu FN;Gao X;Xu W;Ni JQ;Xing Y;Huang L;Hsiao HC;Zheng H;Wang C;Zheng Y;Xiaoli AM;Yang F;Bondos SE;Ji JY
• 通讯作者: Ji JY