Impact of CREBRF and its obesity-risk variant on hypothalamic glucocorticoid and neuroendocrine output using molecular, cellular, and physiological approaches.

项目摘要 强有力的证据将中枢下丘脑神经内分泌输出与复杂的生物学过程联系起来， 控制能量和代谢平衡的行为。克肖博士的合作研究小组最近 在一个假定的转录调节因子CREBRF中发现了一种新的肥胖风险变体，该变体在 下丘脑尽管对CREBRF几乎一无所知，但它与糖皮质激素有关 信号，提高了它在人类中的能量和代谢作用的可能性， 影响下丘脑糖皮质激素和/或神经内分泌输出。本提案的总体目标是 确定CREBRF及其肥胖风险变体如何促进能量稳态的中枢调节 和压力反应。总体目标是，在实现这一目标的过程中， 该基因/变体在中枢下丘脑糖皮质激素和神经内分泌输出中的作用。中央 假设CREBRF在关键的下丘脑神经元中表达和调节， CREBRF或其错义CrebrfR 457 Q的表达将差异性地影响代谢控制转录组 以及下丘脑内的染色质景观，从而影响行为和代谢结果。 这一假说基于以下几点：1）内源性CREBRF在中枢神经系统中高度表达， 系统，包括下丘脑，在那里它与糖皮质激素受体（GR）共定位; 2）异位 CREBRF在细胞中的表达影响亚核GR靶向和稳定性; 3）全球CrebrfKO小鼠具有 糖皮质激素信号传导失调和产后母体行为异常;以及4）全局CrebrfKO小鼠 体重减轻。上述假设将使用分子、细胞和生理学方法进行检验。 具体目标如下：1）描述CREBRF及其肥胖风险变体的影响 （2）使用鼠模型，测定CREBRFR 458 Q对体内下丘脑输出的功能;和 CREBRF及其肥胖风险变体（CREBRFR 458 Q）对染色质可及性和细胞特异性转录组的影响 使用鼠模型。这项研究是创新的，因为1）它在小鼠模型中检查肥胖，而没有 糖尿病的并发症，2）研究机制的表型观察萨摩亚人和3）将奠定 为寻求靶向中枢CREBRF的潜在治疗益处的众多途径奠定了基础。 这一贡献将是重要的，因为它将确定CREBRF的表达，调节和功能， 特定应激条件下下丘脑神经肽神经元和HPA轴输出 并确定CREBRF及其肥胖相关变体对全基因组染色质景观的影响 和下丘脑内的单细胞转录组。这样的发现预计将有广泛的翻译 通过改进预防和/或治疗肥胖症和相关代谢疾病的策略来产生影响。 最后，在完成这项建议后，弗拉姆博士将能够领导她自己的独立研究 神经内分泌学领域的研究项目。

PROJECT SUMMARY Strong evidence links central hypothalamic neuroendocrine output to complex biological processes and behaviors that control energy and metabolic homeostasis. Dr. Kershaw’s collaborative research group recently identified a novel obesity-risk variant in a putative transcriptional regulator, CREBRF, that is highly expressed in the hypothalamus. Although virtually nothing in know about CREBRF, it has been linked to glucocorticoid signaling, raising that possibility that its energy and metabolic effects in humans is mediated, in part, by influencing hypothalamic glucocorticoid and/or neuroendocrine output. The overarching goal of this proposal is to determine how CREBRF and its obesity-risk variant contribute to the central regulation of energy homeostasis and the stress response. The overall objective, which is the next step in the pursuit of this goal, is to characterize the role of this gene/variant in central hypothalamic glucocorticoid and neuroendocrine output. The central hypothesis is that CREBRF is expressed and regulated in key hypothalamic neurons and that the loss of CREBRF or expression of its missense CrebrfR457Q will differentially impact the metabolic control transcriptome and the chromatin landscape within the hypothalamus, thereby influences behavioral and metabolic outcomes. This hypothesis is based on the following: 1) endogenous CREBRF is highly expressed in the central nervous systems including the hypothalamus where it co-localizes with the glucocorticoid receptor (GR); 2) ectopic expression of CREBRF in cells influences subnuclear GR targeting and stability; 3) global CrebrfKO mice have dysregulated glucocorticoid signaling and abnormal postpartum maternal behavior; and 4) global CrebrfKO mice have reduced body weight. The above hypothesis will be tested using molecular, cellular, and physiological approaches with the following specific aims: 1) To characterize the impact of CREBRF and its obesity risk variant (CREBRFR458Q) on hypothalamic output in vivo using murine models; and 2) to determine the function of CREBRF and its obesity risk variant (CREBRFR458Q) on chromatin accessibility and cell-specific transcriptome using murine models. This research is innovative because 1) it examines obesity in a murine model without the complications of diabetes, 2) examine the mechanisms for the phenotype observed in Samoans and 3) will lay the foundation for numerous avenues to pursue the potential therapeutic benefits of targeting central CREBRF. This contribution will be significant because it will identify CREBRF expression, regulation, and function in specific hypothalamic neuropeptide-containing neurons and HPA-axis output during defined stress conditions and determine the impact of CREBRF and its obesity-linked variant on the genome-wide chromatin landscape and single cell transcriptomes within the hypothalamus. Such findings are expected to have a broad translational impact by improving strategies for prevention and/or treatment of obesity and associated metabolic diseases. Finally, at the completion of this proposal, Dr. Frahm will be well poised to lead her own independent research program in the field of neuroendocrinology.