Ischemia-Reperfusion in A2A and A2B Knockout Hearts

描述(由申请人提供)： 这项建议的主要目标是将首席研究员发展成为心血管疾病领域的独立临床科学家。申请者是一名儿科重症监护医生，他积极参与基础科学研究，但离开临床工作的时间有限(35%)。如果得到资助，该奖项将有75%的时间用于研究、培训和追求特定的科学目标。在一位公认的腺苷药理学家的赞助下，该提案包括研究生课程、定期安排的科学研讨会、出席国家会议、科学技术培训，以及进一步参与研究生的辅导。在以大学为基础的医学院的全力支持下，由知名科学家和临床科学家组成的多学科咨询委员会将指导首席研究员的职业发展。这项拟议的研究将考察腺苷A2A和A2B受体在心肌缺血再灌注耐受中的相对作用。腺苷是代谢供需失衡时释放的一种“报复性代谢物”，它通过激活至少四种不同的受体亚型来发挥心脏保护反应。弄清每种腺苷受体亚型对缺血-再灌注反应的贡献(S)仍然是开发心脏病临床治疗潜在药物疗法的关键一步。虽然A2a受体主要负责冠状动脉血流的调节，但它们对保护缺血再灌注的作用才刚刚开始被认识到。关于A2B受体激活在缺血-再灌注期间是否具有保护作用，我们知之甚少，部分原因是缺乏选择性和有效的A2B拮抗剂。利用基因敲除模型的特异性，并将其与传统的受体-配基方法相结合，现在可以通过靶向缺失A2A或A2B受体的两个小鼠系来明确分离这些受体亚型中每一种在缺血再灌注期间的保护作用。其具体目的是：1)研究腺苷A2A和A2B受体敲除小鼠离体心缺血再灌注的影响；2)建立腺苷A2A和A2B受体敲除小鼠心肌局部缺血再灌注的在体模型；3)研究腺苷A2A和A2B受体敲除小鼠心肌缺血再灌注保护的亚细胞信号机制。

DESCRIPTION (provided by applicant): The primary objective of this proposal is the development of the principal investigator into an independent clinician scientist in the field of cardiovascular disease. The applicant is a pediatric critical care physician who actively participates in basic science research albeit with limited time away from clinical duties (35%). If funded, this award will allow 75% time for research training and pursuit of specific scientific aims. Under the sponsorship of a well-recognized adenosine pharmacologist, the proposal includes a curriculum of graduate level courses, regularly scheduled scientific seminars, attendance at national meetings, training in scientific techniques, and further involvement in the mentoring of graduate students. Within the fully supportive setting of a university-based school of medicine, a multidisciplinary advisory committee of established scientists and clinician scientists will guide the career development of the principal investigator. The proposed research will examine the relative roles of adenosine A2A and A2B receptors in myocardial tolerance to ischemia-reperfusion. Adenosine is a "retaliatory metabolite" released during imbalances of metabolic supply and demand that exerts cardioprotective responses through activation of at least four different receptor subtypes. Clarifying the contribution(s) of each adenosine receptor subtype in response to ischemia-reperfusion remains an essential step in developing potential pharmacologic therapies for the clinical management of heart disease. While A2A receptors are primarily responsible for regulation of coronary flow, their contribution to protection from ischemia-reperfusion is just beginning to be appreciated. Less is known about whether A2B receptor activation is protective during ischemia-reperfusion in part due to the unavailability of selective and potent A2B antagonists. Harnessing the specificity of gene-knockout models and combining it with a traditional receptor-ligand approach, it is now possible to distinctly isolate the protective contribution of each of these receptor subtypes during ischemia-reperfusion using two lines of mice with targeted deletion of either A2A or A2B receptors. The specific aims are: 1) Characterize the effects of ischemia-reperfusion in isolated hearts from adenosine A2A and A2B receptor knockout mice, 2) Develop an in vivo model of regional myocardial ischemia-reperfusion in adenosine A2A and A2B receptor knockout mice, and 3) Examine the subcellular signaling mechanisms involved in protection from ischemia-reperfusion in adenosine A2A and A2B receptor knockout mice.