Defining Preadipocyte Signature Genes

描述（由申请人提供）：肥胖在美国是一种流行病，它会导致包括心脏病和2型糖尿病在内的危及生命的疾病的发展。最近的研究表明，成人脂肪组织中存在显著程度的脂肪细胞转换，表明前体前脂肪细胞不断产生成熟脂肪细胞。针对脂肪形成的分子机制的治疗有可能有效地治疗和预防肥胖。脂肪组织中存在的前体脂肪细胞的发育尚不清楚，由于我们无法精确识别这种细胞类型，这一领域的研究受到限制。此外，定义细胞为功能性前脂肪细胞的独特基因群尚未确定。因此，迫切需要开发新的分子工具来研究脂肪细胞前体，并确定和表征脂肪形成的新途径和分子程序。迄今为止，对前脂肪细胞表达的脂肪形成抑制剂的研究表明，这一基因群可能是脂肪形成过程的一个特别丰富的调节来源。本研究项目旨在通过综合方法识别和研究定义功能性前脂肪细胞的基因，解决我们对脂肪细胞谱系和前脂肪细胞/脂肪细胞生物学知识的空白。为了解决这个问题，我们开发并验证了一种新的来自小鼠白色脂肪组织的白色前脂肪细胞培养模型（ScAP-23）。我们将利用该模型和高度表征的3T3-L1白色前脂肪细胞模型以及其他细胞系，分析含有前脂肪细胞的WAT群体。我们的方法将结合基于生物信息学的方法分析转录谱数据，并对已确定的候选基因和脂肪细胞和脂肪细胞中的分子途径进行功能测试。在目标1中，我们将通过对培养和体内移植的前脂肪细胞进行的功能研究，确定新的前脂肪细胞表达的脂肪形成抑制剂和成熟脂肪细胞表型。在目标2中，我们将进行全基因组转录分析，以鉴定在承诺的前脂肪细胞中高度富集和选择性表达的基因。候选的前脂肪细胞承诺/能力基因将通过功能研究的增加来测试间充质前体向前脂肪细胞谱系承诺的作用。它们的敲除对前脂肪细胞承诺和分化的影响也将被确定。我们预测这些研究将揭示脂肪细胞谱系的新分子途径。此外，我们的工作将产生新的基因表达数据集，对研究界非常有用，并将为开发新的分子工具来研究前脂肪细胞奠定重要的基础。

DESCRIPTION (provided by applicant): Obesity is at epidemic proportions in the United States and it contributes to the development of life-threatening illnesses including heart disease and type 2 diabetes. Recent studies have demonstrated a significant degree of adipocyte turnover in adult human adipose tissue, indicative of ongoing production of mature adipocytes from precursor preadipocytes. Therapies that target molecular mechanisms of adipogenesis have the potential to be effective in the treatment and prevention of obesity. The development of adipocytes from precursors present in adipose tissue is not well understood and research in this area has been limited by our inability to precisely identify this cell type. Moreover, the unique cohort of genes that define a cell as a functional preadipocyte has not been determined. As such, there remains a pressing need to develop new molecular tools to study the fat cell precursor and to identify and characterize novel pathways and molecular programs of adipogenesis. Studies with preadipocyte-expressed inhibitors of adipogenesis conducted to date indicate that this gene cohort may be a particularly rich source of regulators of the adipogenic process. This research project is designed to address gaps in our knowledge of the adipocyte lineage and preadipocyte/adipocyte biology via comprehensive approaches to identify and study genes that define functional preadipocytes. To address this we have a developed and validated a new white preadipocyte cell culture model (ScAP-23) derived from murine white adipose tissue. We will utilize this model and the highly characterized 3T3-L1 white preadipocyte model and other cell lines and analysis of preadipocyte-containing populations of WAT. Our approaches will integrate transcriptional profiling data analyzed with bioinformatics-based methodologies and functional testing of identified candidate genes and molecular pathways in preadipocytes and adipocytes. In Aim 1 we will identify novel preadipocyte-expressed inhibitors of adipogenesis and the mature adipocyte phenotype using gain of function studies conducted in preadipocytes in culture and with in vivo transplantation. In Aim 2 we will conduct genome-wide transcriptional analysis to identify genes highly enriched and selectively expressed in committed preadipocytes. Candidate preadipocyte commitment/competence genes will be tested for roles in commitment of mesenchymal precursors to the preadipocyte lineage by gain of function studies. The effect of their knockdown on preadipocyte commitment and differentiation will also be determined. We predict these studies will uncover new molecular pathways for the adipocyte lineage. In addition, our work will generate new gene expression datasets highly useful to the research community and will form an important foundation for the development of new molecular tools to study preadipocytes. PUBLIC HEALTH RELEVANCE: By determining the molecular processes underlying the formation and function of adipose tissue we can better define therapies and treatments for obesity. While there is considerable information on the genes which function in adipocytes, those which that are important for the cell type from which mature adipocytes arise, termed preadipocytes, remain largely unexplored. By better defining these genes and their functions we aim to uncover unique ways to study the development of adipose tissue and control the process of conversion of preadipocytes to adipocytes that will ultimately lead to better understanding and treatment of obesity.