FUNCTION OF THE HYPOTHALAMIC MELANOCORTIN SYSTEM IN STIMULATING COUNTER-REGULATORY RESPONSE TO HYPOGLYCEMIA

这个K 01奖申请的主要目标是获得必要的培训和研究经验，以促进我的 过渡到独立的研究生涯。到目前为止，在我的博士后培训，我已经应用我的技能和知识， 这些都是我在Eric Lazartigues博士的实验室攻读博士学位时学到的。展望未来，我想获得新的 研究技能和开发一个项目，是从博士马尔科姆低（我的博士后导师）正在进行的研究不同。我 我想把我目前在研究外周器官方面的技能与有关中枢器官的新技术结合起来 神经系统我将接受神经药理学，神经解剖学，转基因小鼠开发等方面的培训和课程 使用光学和药物遗传学工具的模型。我的长期职业目标是成为一名独立调查员 在一个主要的学术研究机构，并有助于我们了解大脑的功能， 葡萄糖稳态1型和2型（晚期）糖尿病患者面临危及生命的高风险 由于严格的血糖控制治疗导致的低血糖。正常情况下，肾上腺素和胰高血糖素等激素被释放， 对抗低血糖;然而，糖尿病患者对低血糖的反调节反应受损。 因此，大脑功能由于缺乏葡萄糖而恶化，这些患者可能会出现混乱， 如果不立即治疗，癫痫发作，失去知觉，甚至死亡。在K 01奖励期间，我的目标是确定中央 参与低血糖反调节的途径。我的初步数据显示下丘脑黑皮质素 系统是必不可少的，在抵消低血糖。弓状核特异性Pomc敲除小鼠（ArcPomc-/-）表现出 对葡萄糖缺乏的反应受损。因此，在目标1中，我将确定下丘脑POMC在以下方面的生理作用： 抵消低血糖。我将采用免疫组织化学原位杂交和低血糖钳夹技术 实现目标1。我已经观察到黑皮质素4受体（MC 4 R）激动剂治疗改善，而其拮抗剂治疗改善。 分别是ArcPomc-/-和WT小鼠中的反调节反应。因此，本项目的目标2是 检查MC 4 R的功能，特别是在下丘脑室旁核（PVH， 调节交感神经系统活动）刺激对低血糖的反调节反应。我会雇用 光学和药物遗传学工具来阐明MC 4 RPVH在低血糖反调节中的作用。最后，在Aim 3、研究糖尿病对下丘脑POMC和MC 4 R水平的影响，以确定其机制。 糖尿病期间对低血糖的反应降低。此外，我将测试MC 4 R激动剂在预防生命中的潜力- 链脲佐菌素（STZ）治疗的糖尿病小鼠中的威胁性低血糖。该项目的成果将直接 对预防糖尿病患者致命性低血糖发作意义。重要的是，随着这一进程的发展， 项目，我将能够获得上述技术的专业知识，并为未来的研究生成数据， 申请R 03和R 01赠款。我的指导委员会包括一些科学家，他们都有着杰出的职业生涯， 这将为本项目的所有目标提供尽可能高水平的指导。密歇根大学 沿着的糖尿病研究中心将为我提供一个优秀的设施，以成功地完成我的项目。

The primary goal of this K01 award application is to acquire necessary training and research experience to facilitate my transition to an independent research career. So far in my postdoctoral training, I have applied my skills and knowledge that were learned during my PhD education in Dr. Eric Lazartigues' lab. Moving forward, I would like to acquire new research skills and develop a project that is different from Dr. Malcolm Low's (my postdoc mentor) ongoing research. I would like to integrate my current skills in studying peripheral organs with new techniques pertaining to the central nervous system. I will undertake training and courses in neuropharmacology, neuroanatomy, developing transgenic mouse models employing opto- and pharmaco- genetic tools. My long term career goal is to become an independent investigator at a major academic research-focused institution and to contribute toward our understanding of the function of brain in glucose homeostasis. Patients with both type 1 and type 2 (late stage) diabetes are at high risk of facing life-threating hypoglycemia due to tight glucose control therapy. Normally, hormones such as epinephrine and glucagon are released to counteract hypoglycemia; however, patients with diabetes exhibit impaired counter-regulatory response to hypoglycemia. Consequently, the function of brain deteriorates due to lack of glucose and these patients may experience confusion, seizures, unconsciousness, and death if not treated immediately. During K01 award period, I aim to determine the central pathways involved in hypoglycemia counter-regulation. My preliminary data suggest that hypothalamic melanocortin system is essential in counteracting hypoglycemia. Arcuate nucleus-specific Pomc knockout mice (ArcPomc-/-) exhibit impaired response to glucose deficit. Therefore, in Aim 1, I will determine a physiological role of hypothalamic POMC in counteracting hypoglycemia. I will employ immunohistochemistry, in situ hybridization, and hypoglycemic clamps to accomplish Aim 1. I have observed that melanocortin 4 receptor (MC4R) agonist treatment improves, while its antagonist worsens, the counter-regulatory response in ArcPomc-/- and WT mice, respectively. Hence, Aim 2 of this project is to examine the function of the MC4R specifically in the paraventricular nucleus of the hypothalamus (PVH, a region that regulates sympathetic nervous system activity) in stimulating counter-regulatory response to hypoglycemia. I will employ opto- and pharmaco- genetic tools to elucidate the role of MC4RPVH in hypoglycemia counter-regulation. Finally, in Aim 3, I will examine the impact of diabetes on hypothalamic POMC and MC4R levels to ascertain the mechanism underlying reduced response to hypoglycemia during diabetes. Moreover, I will test the potential of MC4R agonist in preventing life- threatening hypoglycemia in streptozotocin (STZ) treated mice with diabetes. The outcome of this project will have direct implication for prevention of fatal hypoglycemic episodes in patients with diabetes. Importantly, with the progress of this project, I will be able to acquire expertise in the aforementioned techniques, and generate data for future studies and applications for R03 and R01 grants. My mentoring committee includes a number of scientists, with outstanding careers, that will provide guidance of the highest possible level for all of the aims of this project. The University of Michigan along with its Diabetes Research Center will provide me an excellent facility to successfully complete my project.