Dissecting the roles of class IIa HDACs in osteocyte biology

 描述(申请人提供)：骨质疏松影响1000万美国人，与之相关的脆性骨折会导致严重的发病率和死亡率。虽然人们对控制成骨细胞和破骨细胞功能的分子途径了解很多，但对骨骼中最丰富的细胞类型--骨细胞--的了解相对较少。骨细胞产生硬化素，这是一种有效的成骨细胞骨形成抑制物，也是骨质疏松的药物靶点。值得注意的是，现有的唯一一种促进骨形成的骨质疏松症疗法，甲状旁腺激素(PTH)1-34(Teriparatide)，部分是通过减少骨细胞产生的硬化素起作用的。这项拨款提案的重点是阐明控制骨细胞生物学的细胞内机制，重点是硬化素基因的调控和甲状旁腺素对其的控制。IIa类HDACs(HDAC5和HDAC4)一般被认为是骨细胞硬化素产生和骨细胞分化的重要调节因子。目的1将使用多种独立和互补的方法，在体内充分表征IIa类HDAC缺乏对骨细胞生物学的影响。目的2将询问IIa类HDAC在体内甲状旁腺素介导的硬化素抑制中的作用。重要的是，虽然已经知道一些关于IIa类HDAC如何控制skerostin表达的信息，但仍有许多信息尚不清楚。因此，Aim 3将使用尖端蛋白质组学方法在骨细胞中确定新的IIa类HDAC结合蛋白和底物。候选人Wein博士是一名内科医生/科学家，致力于骨骼生物学基础研究的事业。他所受的教育 (医学/博士结合学位)为他提供了在基础科学和人体生理学方面的严格培训。作为一名专攻代谢性骨骼疾病的内分泌学家，他的临床和研究兴趣之间存在着相当大的互补性重叠。除了内部建议的研究之外，Wein博士的职业发展计划将使他能够最大限度地利用MGH内分泌部、哈佛医学院和布罗德研究所的资源，以实现他的职业目标。他已经确定了一位导师Henry Kronenberg博士，他是骨骼生物学和甲状旁腺素行动的全球领导者。Wein博士和Kronenberg计划频繁会面，讨论数据和职业发展。Kronenberg博士已经清楚地确定了Wein博士提出的研究的各个方面，这些研究将构成他独立职业生涯的基础。已经确定了MGH内分泌股和布罗德研究所内的合作者，并成立了一个咨询委员会，以评估进展情况和规划未来方向。Wein博士将经常介绍他的数据，参加MGH内分泌部和布罗德研究所的研讨会和期刊俱乐部，并将在每年的国际会议上介绍他的发现。正式的课程计划包括拨款撰写、公开演讲和计算生物学，以进一步提高他作为一名独立医生/科学家的成功几率。Wein博士近期的职业目标包括与他的导师Kronenberg博士和其中确定的合作者一起获得这份拨款申请中描述的技能，并出版第一作者的手稿，以获得知名度并在骨细胞领域站稳脚跟。Wein博士的长期职业目标是成为一名独立的研究员，研究体内控制骨细胞功能的基本细胞生物学机制。他与Laurie Glimcher博士的博士研究重点是成骨细胞生物学，但在这一点上，他需要额外的骨骼生物学培训，并在体内和体外研究骨细胞。MGH内分泌科拥有这些领域的丰富专业知识，这是一个致力于矿物离子新陈代谢和骨生物学的合作小组，密切关注与人类疾病的理解和治疗相关的问题。这项拨款提案的目标1和目标2将允许Wein博士在研究骨细胞生物学所需的体内方法方面获得经验和专业知识。AIM 3将促进发现对骨细胞功能重要的新基因：作为一名独立的研究人员，Wein博士将使用在这项拨款提案中获得的技能来确定新突变菌株的表型。

 DESCRIPTION (provided by applicant): Osteoporosis affects 10 million Americans, and associated fragility fractures cause significant morbidity and mortality. While a great deal is known about the molecular pathways controlling osteoblast and osteoclast function, relatively little is known about the most abundant cell type in bone, the osteocyte. Osteocytes produce sclerostin, a potent inhibitor of bone formation by osteoblasts and an osteoporosis drug target. Notably, the only existing osteoporosis therapy that boosts bone formation, parathyroid hormone (PTH) 1-34 (teriparatide), works in part by reducing sclerostin production by osteocytes. The focus of this grant proposal is to elucidate the intracellular mechanisms controlling osteocyte biology, with an emphasis on sclerostin gene regulation and its control by PTH. Class IIa HDACs (Hdac5 and Hdac4) have been identified as important regulators of osteocytic sclerostin production and osteocyte differentiation in general. Aim 1 will fully characterize the effects of class IIa HDAC deficiency on osteocyte biology in vivo using multiple independent and complementary approaches. Aim 2 will interrogate the role of class IIa HDACs in PTH-mediated sclerostin suppression in vivo. Importantly, though some information is known about how class IIa HDACs might control sclerostin expression, much remains unknown. Therefore, Aim 3 will determine novel class IIa HDAC binding proteins and substrates in osteocytes using cutting-edge proteomic approaches. The candidate Dr. Wein is a physician/scientist dedicated to a career in basic investigation in skeletal biology. His education (combined MD/PhD degrees) provides him rigorous training in basic science and human physiology. An endocrinologist subspecializing in metabolic bone diseases, considerable and complementary overlap exists between his clinical and research interests. Beyond the research proposed within, Dr. Wein's career development plan will allow him to maximize the resources within the MGH Endocrine Unit, Harvard Medical School, and the Broad Institute to achieve his career goals. He has identified a mentor, Dr. Henry Kronenberg, who is a worldwide leader in skeletal biology and PTH actions. Dr. Wein and Kronenberg have a plan for frequent meetings to discuss data and career development. Dr. Kronenberg has clearly identified aspects of the research proposed by Dr. Wein which will form the basis of his independent career. Collaborators within the MGH Endocrine Unit and at the Broad institute have been identified, and an advisory committee has been formed to evaluate progress and plan future directions. Dr. Wein will frequently present his data and attend seminars and journal clubs in the MGH Endocrine Division and at the Broad Institute, and will present his findings at international meetings on an annual basis. Formal coursework is planned in grant writing, public speaking, and computational biology to further enhance his probability of success as an independent physician/scientist. Dr. Wein's immediate career goals include acquiring the skills described in this grant proposal in conjunction with his mentor Dr. Kronenberg and collaborators identified within, and publishing first authors manuscripts in order to gain name recognition and to establish himself in the osteocyte field. Dr. Wein's long-term career goal is to establish himself as an independent investigator studying basic cell biology mechanisms controlling bone cell function in vivo. His PhD work with Dr. Laurie Glimcher focused on osteoblast biology, but at this point he needs additional training in skeletal biology and studying osteocytes in vivo and in vitro. Substantial expertise in these areas is present within MGH Endocrine Unit, a collaborative group dedicated to mineral ion metabolism and bone biology, with close attention to relevance to the understanding and treatment of human disease. Aims 1 and 2 of this grant proposal will allow Dr. Wein to gain experience and expertise in the in vivo approaches required to study osteocyte biology. Aim 3 will facilitate the discovery of new genes important for osteocyte function: as an independent investigator, Dr. Wein will then use the skills acquired in this grant proposal to determine the phenotype of novel mutant strains.