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，在儿童发育过程中发挥关键作用。在人类青春期，性腺类固醇激素分泌增加，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传导的中断可能导致持续到成年的发育缺陷。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节机制，极大地有助于促进儿童的健康发育。本项目的最终目标是以果蝇为模式生物，阐明类固醇激素释放和运输的未知机制和调节机制。为了实现这一目的，主要研究者将检验昆虫类固醇激素蜕皮激素以囊泡介导的方式从类固醇生成组织分泌的假设，挑战所有类固醇激素通过自由扩散分泌的传统观点。在该项目的第一个指导阶段，主要研究者将与明尼苏达大学的导师Michael奥康纳密切合作，开发一些阐明其假设所需的关键体外方法。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激素生成组织培养。该项目的第一步将帮助主要研究者掌握进行下一步项目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有关教学和科学交流的广泛培训，这将有助于他职业生涯的下一个独立阶段。在随后的独立研究者阶段，主要研究者将通过筛选在类固醇生成组织中工作的G蛋白偶联受体，研究推定的囊泡介导的蜕皮激素释放的调节机制。他还将筛选一个假定的蜕皮激素进口所需的吸收外周组织。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生物体中是如何保守的。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，并将影响对发育和疾病过程的广泛研究。

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.