Metabolite channeling in the urea cycle and production of nitric oxide

描述(由申请人提供)： 该提案描述了一项为期5年的指导培训经验，旨在引导您在学术医学领域取得独立的职业生涯。申请人拥有医学博士学位，具有分子生物学、生物化学和细胞生物学的研究经验；她目前正在完成临床遗传学研究。贝勒医学院的环境在医学遗传学的各个方面(临床护理、诊断实验室和研究)以及基础科学研究方面提供了独特的优势组合。实验室导师是尿素循环紊乱(UCD)领域的世界知名领导者，咨询委员会成员经过精心挑选，以提供拟议研究项目的几个方面的专业知识，并为医生-科学家申请者提供职业指导。该项目结合了小鼠遗传学、代谢通量研究和人类临床研究，剖析了内源性尿素循环衍生的精氨酸通量对一氧化氮(NO)产生的贡献。我们将使用小鼠模型和人类患者研究精氨酸和NO在健康和特定疾病中的产生，在这些疾病中，NO在发病机制中已被证实发挥了作用。该项目的具体目标包括建立和鉴定一种新的条件基因敲除小鼠模型，在该模型中，肾脏内源性、细胞内精氨酸的产生受到损害。结果将与出现高精氨酸血症和精氨酸缺乏症的人类患者进行比较。尿素循环障碍是一种酶缺乏，可以深入了解精氨酸的供应如何影响全身NO的产生。通过了解这一点，我们可能能够合理地设计出针对糖尿病、肾功能衰竭和心血管疾病等疾病的无调节失调的药物治疗方法。虽然这些治疗方法中的许多仍然是推测的，但更好地了解调节这一功能的潜在机制最终将提高我们实施此类治疗的能力。这项提议将为申请者提供关于人类和小鼠遗传学以及动态稳定同位素测量方面的新技术的培训。这段时间的科学设计、实施和沟通指导培训将补充申请者作为临床医生的持续发展，最终导致独立的研究计划和长期的学术医学职业生涯。 公共卫生相关性：NO在高血压、糖尿病、哮喘等常见疾病的发病机制中具有已被证实的作用。细胞中精氨酸底物的可获得性对NO合成的影响尚不清楚。我们的工作结合了小鼠模型、最新的输液策略和人类尿素循环患者，以了解这种贡献在肾脏疾病中的作用。此外，这项工作可能为NO的调控和操纵找到一个新的靶点。

DESCRIPTION (provided by applicant): The proposal describes a 5 year mentored training experience designed to lead to an independent career in academic medicine. The applicant holds both MD and PhD degrees with research experience in molecular biology, biochemistry and cell biology; she is currently completing a clinical genetics fellowship. The environment at Baylor College of Medicine provides a unique combination of strengths in a variety of aspects of medical genetics (clinical care, diagnostic labs, and research) as well as basic science research. The laboratory mentor is a world renowned leader in the field of urea cycle disorders (UCD) and the members of the advisory committee have been carefully selected to provide expertise in several aspects of the proposed research project as well as provide career guidance for the physician-scientist applicant. The project combines mouse genetics, metabolic flux studies, and human clinical research to dissect the contribution of endogenous, urea cycle-derived Arginine flux to Nitric Oxide (NO) production. We will study Arginine and NO production in health and in specific diseases where NO has a proven role in the pathogenesis using both mouse models and human patients. The specific aims of this project include generating and characterizing a novel conditional knockout mouse model in which endogenous, intracellular Arginine production by the kidney is impaired. The results will be compared to human patients presenting with hyperargininemia and Arginine deficiency. Urea cycle disorders are enzymatic deficiencies that can provide insight into how Arginine availability may affect whole body NO production. By understanding this, we may be able to rationally devise pharmacological treatment for NO dysregulation in diseases such as diabetes, renal failure, and cardiovascular disease. While many of these therapeutic approaches remain speculative, better understanding of the underlying mechanisms that regulate the function will ultimately improve our ability to implement such therapies. This proposal will provide the applicant with training in new technologies in both human and mouse genetics, and dynamic stable isotope measurements. This period of mentored training in scientific design, implementation and communication will complement the applicant's continued development as a clinician, eventually resulting in an independent research program and a long-term career in academic medicine. PUBLIC HEALTH RELEVANCE: NO has a proven role in the pathogenesis of common diseases as hypertension, diabetes, asthma etc. The impact of arginine substrate availability in the cell on NO synthesis is unknown. Our work combines mouse models, state of the art infusion strategies and human urea cycle patients to understand this contribution in renal disease. Moreover, this work may identify a novel target for regulation and manipulation of NO.