Fatty acid Control Obesity and the Metabolic Syndrome via TPR proteins

描述（由申请人提供）：CDC估计大约32%的美国人肥胖，甚至更多，66%的人超重或肥胖。通过饮食摄入或补充控制来控制肥胖的因素非常令人感兴趣。不饱和脂肪酸，特别是多不饱和脂肪酸，在临床和动物研究中已显示可用于控制哺乳动物的脂质储存和调节体重和肥胖。控制这些行为背后的分子机制尚不清楚。诸如库欣综合征、肥胖症、2型糖尿病、心血管疾病和代谢综合征的疾病已经与糖皮质激素对身体的作用相关联。糖皮质激素受体复合物的改变，无论是积极的或消极的，已被我们的实验室证明是有用的，在研究这些疾病。我们的实验室最近发现了一种很有前途的方法，涉及通过四肽重复（TPR）蛋白，如FKBP 52，FKBP 51，Cyp40和PP 5调节GR。例如，我们已经产生了FKBP52缺陷小鼠，这些小鼠在出生时是可行的，并且在成年后明显正常（除了不孕症）。然而，源自FKBP 52 KO小鼠的细胞具有降低的GR活性。因此，FKBP52不是GR的全局调节剂，因为这种作用，如GR KO小鼠，应导致围产期致死。引人注目的是，我们的FKBP 52杂合小鼠在喂食高脂肪饮食时获得与代谢综合征相似的症状;其中它们发展为高血糖症、高脂血症、高胰岛素血症和体重增加。另一方面，我们最近的数据表明，FKBP51和PP5对GR具有相似的调节作用。我们发现，FKBP51缺陷小鼠在喂食高脂饮食时，血浆甘油三酯水平显著降低，并且缺乏在内脏脂肪组织中储存脂肪酸的能力，这可能是由于抑制性FKBP51的丧失导致GR活性增加。PP5的缺失还导致GR转录活性增加，以及GR磷酸化增强。此外，在脂肪生成研究中，与WT MEF细胞相比，PP5 KO和FKBP 51 KO MEF细胞积累较少的脂肪酸。这表明TPR蛋白在细胞内脂质的储存和积累中起主要作用，并且是控制体内GR作用的可能方法。基于上述，我们提出了一个假设，其中TPR蛋白可能参与脂质储存，出口或代谢结合脂肪酸，并可能导致随后的调节GR。我们进一步预测，PP5缺陷小鼠在高脂饮食的反应应该是高度不敏感的发展内脏肥胖，也许是整体肥胖，使我们能够测试糖尿病和心血管疾病的后续研究。

DESCRIPTION (provided by applicant): The CDC estimates that approximately 32 percent of Americans are obese, even more, 66 percent are overweight or obese. Factors that control obesity via dietary intake or supplemental control are of much interest. Unsaturated fatty acids, especially polyunsaturated fatty acids, have been shown in clinical and animal studies to be useful in controlling lipid storage and regulating body weight and obesity in mammals. The molecular mechanisms behind what controls these actions are not well understood. Diseases such as Cushing Syndrome, obesity, type 2 diabetes, cardiovascular disease and the Metabolic Syndrome have been linked to the actions of glucocorticoids on the body. Alterations to the glucocorticoid receptor complex, either positively or negatively, has been shown by our laboratory to be useful in studying these diseases. Our laboratory has recently uncovered a promising approach that involves regulation of GR by tetratricopeptide repeat (TPR) proteins, such as FKBP52, FKBP51, Cyp40 and PP5. For example, we have generated FKBP52-deficient mice, which are viable at birth and apparently normal into adulthood (except for infertility). Yet, cells derived from FKBP52 KO mice have reduced GR activity. Thus, FKBP52 is not a global regulator of GR, as such an effect, like GR KO mice, should result in peri-natal lethality. Strikingly, our FKBP52 heterozygous mice, when fed a high fat diet, acquire symptoms similar to the Metabolic Syndrome; in which they develop hyperglycemia, hyperlipidemia, hyperinsulinemia and weight gain. On the other hand, our most recent data suggest that both FKBP51 and PP5 have similar modulatory effects on GR. We have found that FKBP51-deficient mice, when fed high-fat diets, have significantly lower triglyceride plasma levels and lack the ability to store fatty acids in the visceral adipose tissue, possibly due to increased GR activity resulting from loss of inhibitory FKBP51. The loss of PP5 also results in increased GR transcriptional activity, as well as, augmented phosphorylation of GR. Furthermore, in an adipogenesis study, PP5 KO and FKBP51 KO MEF cells accumulated less fatty acids compared to WT MEF cells. This suggested that TPR proteins play major roles in storage and accumulation of intracellular lipids and is a possible method of controlling GR actions in the body. Based on the above, we propose a hypothesis in which TPR proteins may participate in lipid storage, export or metabolism by binding fatty acids, and possibly leading to subsequent regulation of GR. We further predict that PP5-deficient mice in response to high-fat diets should be highly insensitive to development of visceral obesity and perhaps overall obesity, allowing us to test for diabetes and cardiovascular disease in follow-up studies.