Modulation of PPAR-gamma phosphorylation at S273 regulates insulin sensitivity

描述（由申请人提供）：ppar - γ是非常有效但有争议的糖尿病药物噻唑烷二酮的靶标。我们最近证明，这些药物通过一种以前未被认识的机制逆转胰岛素抵抗——逆转ppar - γ -磷酸化抑制事件。ppar - γ丝氨酸273的磷酸化发生在高脂肪饮食喂养开始后不久，并随着肥胖的进展而增加。这种磷酸化与ppar - γ靶基因（如脂联素）的失调有关。用噻唑烷二酮治疗患者或小鼠可以逆转磷酸化，因为它可以改善胰岛素敏感性。利用一种新的小鼠模型，我们将研究预防这种肥胖介导的PPAR-gamma S273磷酸化是否会改变体内脂肪组织形态、基因表达和全身胰岛素敏感性。为了做到这一点，我们产生了脂肪特异性敲除相关ppar - γ激酶Cdk5的小鼠。我们预测，由于胰岛素敏感的脂肪组织，这些小鼠将成为健康肥胖的模型。在这些小鼠中诱导饮食诱导的肥胖后，我们将检测肥胖小鼠脂肪组织中的身体组成、葡萄糖稳态和ppar - γ靶基因表达。我们将比较用罗格列酮等完全激动剂治疗野生型Cdk5 KO小鼠和SR1664等非激动剂治疗野生型Cdk5 KO小鼠的代谢和转录结果。此外，我们将研究糖尿病易感基因Cdkal1是否调节小鼠和人类细胞中的PPAR-gamma S273磷酸化和脂肪细胞基因表达。该提议定义了一种新的机制，选择性靶向PPAR-gamma S273磷酸化可能允许特异性地促进PPAR-gamma激活的有益作用而不产生不利影响。候选人亚历山大·班克斯博士在创新研究方面有着良好的记录，专注于人类代谢疾病的转基因小鼠模型的产生和表征。他曾在哥伦比亚大学和哈佛大学进行博士后培训，并在哺乳动物对衰老，肥胖和糖尿病的生理反应研究方面有经验。候选人的职业目标是成为一名独立的学术研究者和教师导师，在研究实验室为理解和逆转代谢疾病做出贡献。这项研究将在哈佛医学院的Bruce Spiegelman博士的实验室进行，他是分子糖尿病研究领域的领导者。共同导师将由David Altshuler，医学博士和哈佛医学院的博士贡献。增加培训经验的职业发展活动包括使用尖端方法进行指导、参加科学会议和支持在有关主题方面具有广泛专门知识的科学咨询委员会。

DESCRIPTION (provided by applicant): PPAR-gamma is the target of highly effective but controversial diabetes medications, the thiazolidinediones. We recently demonstrated that these drugs reverse insulin resistance through a previously unappreciated mechanism-reversing an inhibitory PPAR-gamma-phosphorylation event. Phosphorylation of PPAR-gamma at serine 273 occurs shortly after the onset of high fat diet feeding and increases with progressive obesity. This phosphorylation correlates with dysregulation of PPAR-gamma target genes, such as adiponectin. Treatment of patients or mice with thiazolidinediones reverses phosphorylation as it improves insulin sensitivity. Utilizing a new mouse model we will investigate whether preventing this obesity-mediated PPAR-gamma S273 phosphorylation will alter adipose tissue morphology, gene expression and systemic insulin-sensitivity in vivo. To do this, we have generated mice with an adipose-specific knock-out of the relevant PPAR-gamma kinase, Cdk5. We predict that these mice will be a model of healthy obesity due to insulin-sensitive adipose tissue. Following the induction of diet-induced obesity in these mice, we will examine body composition, glucose homeostasis and PPAR-gamma target gene expression in adipose tissue from obese mice. We will compare the metabolic and transcriptional consequences of treating wild type Cdk5 KO mice treated with full agonists such as rosiglitazone against non-agonists such as SR1664. Furthermore, we will examine whether a diabetes susceptibility gene, Cdkal1, regulates PPAR-gamma S273 phosphorylation and adipocyte gene expression in mouse and human cells. This proposal defines a new mechanism whereby selectively targeting PPAR-gamma S273 phosphorylation may allow for specifically promoting the beneficial effects of PPAR-gamma activation without the adverse effects. The candidate, Dr. Alexander Banks, has a strong track record of innovative research with a focus on generating and characterizing genetically modified mouse models of human metabolic disease. He has performed postdoctoral training at Columbia and Harvard Universities and has experience in the study of mammalian physiologic response to aging, obesity, and diabetes. The candidate's career goal is to become an independent academic investigator and faculty mentor with a research laboratory contributing towards understanding and reversing metabolic diseases. This research will be conducted in the laboratory of Bruce Spiegelman, PhD at Harvard Medical School, who is a leader in field of molecular diabetes research. Co-mentorship will be contributed by David Altshuler, MD, PhD also of Harvard Medical School. Career development activities to augment the training experience include instruction using cutting-edge methods, attending scientific meetings, and the support of a scientific advisory committee with broad expertise in relevant subjects.