Transcriptional regulation by Egr3 in sympathetic nervous system development

Egr3在交感神经系统发育中的转录调节

• 批准号: 7914016
• 负责人: David Hon Quach
• 金额: $ 3.32万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7914016
• 关键词: Affect; Binding; Biological Assay; Cells; Congenital neurologic anomalies; Degenerative Disorder; Development; Disease; Dysautonomias; Gene Mutation; Gene Targeting; Genes; Heparan Sulfate Proteoglycan; Knockout Mice; Knowledge; Location; Mus; Nerve Growth Factors; Neurons; Neurotrophic Tyrosine Kinase Receptor Type 1; Physiological; Regulation; Role; Signal Transduction; Sympathetic Nervous System; Sympathetic Nervous System Diseases; Testing; Transcriptional Regulation; human disease; in vitro Assay; insight; mouse model; nervous system development; novel; public health relevance; transcription factor

DESCRIPTION (provided by applicant): Most of what is known about the development of the sympathetic nervous system (SNS) is limited to molecules with essential functions such as Nerve Growth Factor (NGF). Since loss of NGF and immediate downstream molecules such as its cognate receptor, TrkA, result in near complete loss of the SNS, they offer little clues to the underlying causes of SNS diseases which are far less severe. Instead studies of genes further downstream of NGF signaling such as Egr3, a transcription factor shown to be regulated by NGF, will likely offer better insight into disease. Deletion of Egr3 in the germline results in mice with abnormalities in SNS development and physiologic dysautonomia bearing similarities to human diseases. The proposed study will further extend our understanding of Egr3 function by (1) testing the hypothesis that Egr3 is a sympathetic neuron autonomous regulator of SNS development and (2) defining the role it has independent of NGF signaling in sympathetic neurons. This will be accomplished by generating novel mouse models that will specifically delete Egr3 in sympathetic neurons and specifically over-express Egr3 in sympathetic neurons. Morphological and physiological assays will then be used to determine whether cell-autonomous manipulation of Egr3 affects SNS development. Along with determining the necessity of Egr3 in SNS development, studies will be done to better understand the mechanisms by which it affects sympathetic neuron differentiation. Thus, a newly identified Egr3 target gene, hs3st2, which is involved in heparan sulfate proteoglycan (HSPG) synthesis, will be further examined. Since our initial studies have confirmed that Egr3 can regulate hs3st2 and previous studies have implicated the importance of HSPGs in nervous system development, the second aim of this proposed study will be to (1) better characterize the regulation of hs3st2 by Egr3 and (2) determine whether hs3st2 has an important role in SNS development. Various in vitro assays will be used to determine whether regulation of hs3st2 by Egr3 is either direct or indirect and if it is direct, the exact location of binding will be established. To determine whether hs3st2 is required for SNS development, hs3st2 germline null mice will be examined to assess whether they have any SNS abnormalities that are reminiscent of those seen in Egr3-deficient mice. PUBLIC HEALTH RELEVANCE: The SNS is susceptible to a variety of developmental and degenerative diseases that afflict millions of people worldwide. A few of the SNS diseases have been reliably associated with specific gene mutations, but the vast majority of them have no identifiable cause, thus highlighting our still limited knowledge of the details of SNS development. Egr3 is a gene shown to be involved in SNS development and thus by further elucidating the mechanisms through which it acts we will gain a better understanding of how the SNS develops and how its function can be impaired by disease.

描述（由申请人提供）：关于交感神经系统（SNS）发育的大部分已知信息仅限于具有基本功能的分子，例如神经生长因子（NGF）。由于 NGF 及其直接下游分子（例如其同源受体 TrkA）的丧失会导致 SNS 几乎完全丧失，因此它们对 SNS 疾病的根本原因几乎没有提供任何线索，而这些疾病的严重程度要低得多。相反，对 NGF 信号下游基因（例如 Egr3，一种被证明受 NGF 调节的转录因子）的研究可能会提供对疾病的更好的了解。种系中 Egr3 的缺失会导致小鼠出现 SNS 发育异常和与人类疾病相似的生理自主神经功能障碍。拟议的研究将通过以下方式进一步扩展我们对 Egr3 功能的理解：(1) 检验 Egr3 是 SNS 发育的交感神经元自主调节因子的假设；(2) 定义其独立于交感神经元中 NGF 信号传导的作用。这将通过生成新的小鼠模型来实现，该模型将特异性删除交感神经元中的 Egr3 并特异性地在交感神经元中过度表达 Egr3。然后使用形态学和生理学测定来确定 Egr3 的细胞自主操作是否会影响 SNS 的发育。除了确定 Egr3 在 SNS 发育中的必要性之外，还将进行研究以更好地了解它影响交感神经元分化的机制。因此，新鉴定的 Egr3 靶基因 hs3st2 参与硫酸乙酰肝素蛋白多糖（HSPG）的合成，将得到进一步研究。由于我们的初步研究已证实 Egr3 可以调节 hs3st2，并且之前的研究暗示了 HSPG 在神经系统发育中的重要性，因此本研究的第二个目的将是（1）更好地表征 Egr3 对 hs3st2 的调节，以及（2）确定 hs3st2 是否在 SNS 发育中具有重要作用。将使用各种体外测定来确定Egr3对hs3st2的调节是直接的还是间接的，如果是直接的，则将确定结合的确切位置。为了确定 SNS 发育是否需要 hs3st2，将对 hs3st2 种系缺失小鼠进行检查，以评估它们是否具有任何与 Egr3 缺陷小鼠中所见的 SNS 异常。 公共健康相关性：社交网络很容易受到各种发育性疾病和退行性疾病的影响，这些疾病困扰着全世界数百万人。一些 SNS 疾病已可靠地与特定基因突变相关，但其中绝大多数没有可识别的原因，从而凸显出我们对 SNS 发展细节的了解仍然有限。 Egr3 是一个被证明参与 SNS 发育的基因，因此通过进一步阐明其作用机制，我们将更好地了解 SNS 如何发育以及其功能如何因疾病而受损。