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

申请K01奖项的主要目的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，在博士后培训中，我运用了我的技能和知识 这是我在埃里克·拉扎蒂格博士的实验室攻读博士学位期间学到的。展望未来，我想获得新的 研究技能，并开发一个不同于马尔科姆·洛博士(我的博士后导师)正在进行的研究的项目。我 我想把我目前研究外周器官的技能与与中央器官有关的新技术结合起来 神经系统。我将接受神经药理学、神经解剖学、转基因小鼠开发方面的培训和课程。 使用光学和药物遗传工具的模型。我的长期职业目标是成为一名独立调查员 在一家主要的学术研究机构工作，并帮助我们理解大脑的功能 葡萄糖动态平衡。同时患有1型和2型(晚期)糖尿病的患者面临生命威胁的风险很高。 由于严格的血糖控制治疗而导致的低血糖。正常情况下，肾上腺素和胰高血糖素等激素被释放到 对抗低血糖；然而，糖尿病患者表现出对低血糖的反向调节反应受损。 因此，由于缺乏葡萄糖，大脑功能恶化，这些患者可能会出现混乱， 如果不立即治疗，癫痫发作、昏迷和死亡。在K01颁奖期间，我的目标是确定中环 参与低血糖逆调节的通路。我的初步数据显示，下丘脑黑素皮质素 系统在对抗低血糖方面是必不可少的。弓状核特异性Pomc基因敲除小鼠(ArcPomc-/-)的研究 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 对抗低血糖。我将采用免疫组织化学、原位杂交和降糖钳夹技术 完成目标1.我观察到黑素皮质素4受体(MC4R)激动剂的治疗效果有所改善，而其拮抗剂 ArcPomc-/-和WT小鼠的反调节反应分别恶化。因此，这个项目的目标2是 研究MC4R在下丘脑室旁核(PVH)的功能。 调节交感神经系统活动)刺激对低血糖的逆调节反应。我会聘用 光遗传学和药物遗传学工具，以阐明MC4RPVH在低血糖反调节中的作用。最后，在AIM中 3，我将研究糖尿病对下丘脑POMC和MC4R水平的影响，以确定其机制 糖尿病期间对低血糖的反应减弱。此外，我将测试MC4R激动剂在预防生命- 链脲佐菌素(STZ)治疗糖尿病小鼠的威胁低血糖。这个项目的成果将直接影响到 对预防糖尿病患者发生致命性低血糖的启示。重要的是，随着这一进程的进展 在项目中，我将能够获得上述技术方面的专业知识，并为未来的研究和 申请R03和R01助学金。我的指导委员会包括一些科学家，他们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 连同它的糖尿病研究中心将为我成功完成我的项目提供一个极好的设施。

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.