Antiobesity Mechanism of CLA Isomer in Human Adipocytes

描述（由申请人提供）：项目概述。该项目的长期目标是开发新的饮食策略来控制人类肥胖，这是美国最普遍的营养相关疾病。本应用程序的目的是确定异构体特异性机制，通过该机制，在牛肉，乳制品和膳食补充剂中发现的共轭亚油酸（CLA），脂肪酸（FA）可以减少某些动物和人类的肥胖，降低人类脂肪细胞中的甘油三酯（TG）含量。该建议的中心假设是反式- 10，cis -12 CLA激活脂质信号，抑制过氧化物酶体增殖物激活受体(PPAR)-？活性，从而减少葡萄糖和FAs合成TG的摄取。这一假设是基于我们的研究结果，表明反式-10，顺式-12 CLA，而不是顺式-9，反式-11 CLA，直接增加饱和FAs与单不饱和FAs的比例，并激活抑制PPAR？活动。CLA的这些作用依赖于丝裂原活化蛋白激酶/细胞外信号调节激酶（MEK/ERK）和核因子κ B (NF？B)信号。这项研究的基本原理是，一旦我们了解了反式-10，顺式-12 CLA如何降低人体脂肪细胞的TG含量并确定潜在的代谢后果，就可以有效地评估其作为控制肥胖的膳食补充剂的有效性和安全性。为了实现这些目标，将在人（前）脂肪细胞的原代培养中检查以下具体目标：目标#1。确定CLA调控PPAR的机制？在脂肪细胞;目标# 2。确定NF的作用？前脂肪细胞和脂肪细胞B和MEK/ERK信号在CLA抑制PPAR中的作用和目标3。确定CLA或其代谢物如何影响诱导脱脂的信号。在目标#1中，我们将研究CLA对PPAR转录和稳定性的影响。靶基因，PPAR？磷酸化、配体诱导的PPRE报告基因激活和PPAR？、共激活因子、共抑制因子和基础转录因子对内源性PPAR？目标基因。在

DESCRIPTION (provided by applicant): Project Summary. The long-term goal of this project is to develop novel dietary strategies for the control of human obesity, the most prevalent nutrition-related disease in America. The objective of this application is to identify isomer-specific mechanisms by which conjugated linoleic acid (CLA), fatty acid (FA)s found in beef, dairy foods, and dietary supplements that decrease adiposity in certain animals and humans, reduces the triglyceride (TG) content of human adipocytes. The central hypothesis for this proposal is that trans-10, cis-12 CLA activates lipid-borne signals that suppress peroxisome proliferator activated receptor (PPAR)-? activity, thereby reducing the uptake of glucose and FAs for TG synthesis. This hypothesis is based on our findings demonstrating that trans-10, cis-12 CLA, but not cis-9, trans-11 CLA, directly increases the ratio of saturated FAs to monounsaturated FAs, and activates proinflammatory signals that suppress PPAR? activity. These actions of CLA are dependent on mitogen-activated protein kinase / extracellular signal-regulated kinase kinase (MEK/ERK) and nuclear factor kappa B (NF?B) signaling. The rationale for this research is that once we understand how trans-10, cis-12 CLA reduces the TG content of human adipocytes and identify potential metabolic consequences, it's effective and safe use as a dietary supplement for controlling obesity can be evaluated effectively. To accomplish these objectives, the following specific aims will be examined in primary cultures of human (pre) adipocytes: Aim #1. Identify the mechanism by which CLA regulates PPAR? in adipocytes; Aim #2. Determine the role of NF?B and MEK/ERK signaling in preadipocytes and adipocytes in mediating CLA's suppression of PPAR?; and Aim #3. Determine how CLA or its metabolites impact on signals that induce delipidation. In Aim #1, we will examine CLA's effects on the transcription and stability of PPAR? target genes, PPAR? phosphorylation, ligand-induced activation of a PPRE reporter, and recruitment of PPAR?, co-activators, co-repressors, and basal transcription factors to endogenous PPAR? target genes. In Aim #2, we will investigate the impact of chemical inhibitors and siRNAs targeting NF?B and MEK/ERK on the induction of our candidate cytokines and PPAR? target genes and on glucose and FA uptake and metabolism. In Aim #3, we will examine CLA's isomer-specific effects on the synthesis of lipids and cell signals known to activate NFKB and/or MEK/ERK and cause delipidation. Relevance. The proposed studies are significant because they are expected to lead to an in-depth understanding of the mechanism of action of CLA isomers and to promote the development of novel and safe dietary strategies for weight loss. As a consequence, reductions in health problems and financial costs related to obesity would be expected.