Molecular mechanisms of steroid hormone secretion and trafficking

描述（由申请人提供）：类固醇激素是一个大家族的分子，在儿童发育中起关键作用。在人类的青春期，性腺类固醇激素分泌的增加产生第二性征，如乳房发育和面部毛发的出现。由于类固醇激素在成熟过程中的重要作用，儿童时期类固醇激素信号的中断可能导致持续到成年期的发育缺陷。因此，了解正常和病理条件下类固醇激素信号传导的机制和调控机制，对促进儿童健康发育有很大的帮助。本项目的最终目标是通过果蝇作为模式生物，阐明迄今未知的类固醇激素释放和运输的机制和调控机制。为了达到这一目的，首席研究员将测试昆虫类固醇激素蜕皮激素是通过囊泡介导的方式从类固醇组织分泌的假设，挑战所有类固醇激素都是通过自由扩散分泌的传统观点。在项目的第一个指导阶段，首席研究员将与他在明尼苏达大学的导师Michael O'Connor密切合作，开发一些关键的体外方法，以阐明他的假设。这些方法包括蜕皮激素的免疫组化检测、体外转运蛋白测定和体外类固醇组织培养。项目的第一步将帮助首席研究员掌握进行项目下一步所需的各种生物化学和细胞生物学技术。在指导阶段，首席研究员还将接受广泛的教学和科学交流培训，这将有助于他的职业生涯的下一个独立阶段。在随后的独立研究阶段，首席研究员将通过筛选在类固醇生成组织中起作用的G蛋白偶联受体，研究假设的囊泡介导的蜕皮激素释放的调节机制。他还将筛选被外周组织摄取所需的假定蜕皮激素输入源。这些方法应该告诉我们，这种类固醇激素分泌和运输的新机制在不同的生物中是如何保守的。从长远来看，首席研究员的工作有可能改变类固醇激素作用的范式，并将对发育和疾病过程的广泛研究产生影响。

DESCRIPTION (provided by applicant): Steroid hormones are a large family of molecules that play pivotal roles during childhood development. During puberty in humans, elevated secretion of gonadal steroid hormones produces secondary sex characteristics such as breast development and the appearance of facial hair. Because of such important roles of steroid hormones in maturation processes, disruption of steroid hormone signaling during childhood can cause developmental defects that last into adulthood. Understanding the machinery and regulatory mechanisms of steroid hormone signaling in normal as well as pathological conditions, therefore, contributes greatly to the promotion of healthy childhood development. The ultimate goal of this project is to elucidate as-yet-unknown machinery and regulatory mechanisms of steroid hormone release and trafficking, by using the fruitfly Drosophila as a model organism. In order to accomplish this purpose, the Principal Investigator will test the hypothesis that the insect steroid hormone ecdysone is secreted from the steroidogenic tissue in a vesicle-mediated manner, challenging the conventional idea that all steroid hormones are secreted by free diffusion. During the first mentored phase of the project, the Principal Investigator will work closely with his mentor, Michael O'Connor, at the University of Minnesota to develop some key in vitro methods necessary to elucidate his hypothesis. Those methods include the immunohistochemical detection of ecdysone, in vitro transporter assay and in vitro steroidogenic tissue culture. This initial step of the proposed project will help the Principal Investigator master various biochemistry and cell biology techniques required to conduct the next step of the project. During the mentored phase, the Principal Investigator will also undergo extensive training on teaching and scientific communication, which will be helpful in the next independent phase of his career. In the subsequent independent investigator phase, the Principal Investigator will work on the regulatory mechanisms of the putative vesicle-mediated ecdysone release, by screening G protein-coupled receptors working in the steroidogenic tissue. He will also screen for a putative ecdysone importer required for its uptake by peripheral tissues. These approaches should tell us how well this novel machinery of steroid hormone secretion and trafficking is conserved among different organisms. In the long run, the Principal Investigator's work has the potential to shift the paradigm of steroid hormone action and will impact a vast range of research on developmental and disease processes.