Mechanisms and significance of programmed cell death in hypothalamic CRH neurons

下丘脑CRH神经元程序性细胞死亡的机制及意义

• 批准号: 10566449
• 负责人: YUCHIN Albert Pan
• 金额: $ 40万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2027-10-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10566449
• 关键词: Address; Affect; Animals; Anxiety; Apoptosis; Brain; CRISPR/Cas technology; Cell Count; Cell Death; Cells; Corticotropin; Corticotropin-Releasing Hormone; Development; Disease; Down Syndrome Cell Adhesion Molecule; Excitatory Synapse; Functional disorder; Future; Genetic; Glucocorticoid Receptor; Glucocorticoids; Growth; Health; Hormones; Hydrocortisone; Hypothalamic structure; Image; Impairment; Knowledge; Measures; Mediating; Mental Depression; Mental disorders; Modeling; Molecular; Monitor; Mutate; NRCAM gene; Neurons; Neurosecretory Systems; Optics; Pathway interactions; Pattern; Pituitary Gland; Play; Population; Regulation; Retina; Risk; Rodent; Role; Stress; Synapses; System; Testing; Zebrafish; acute stress; analog; biological adaptation to stress; cell type; early life stress; experimental study; gain of function; hypothalamic-pituitary-adrenal axis; interest; mutant; neural; neural circuit; neuron loss; neuronal excitability; neuronal survival; novel therapeutics; postsynaptic neurons; presynaptic neurons; stress related disorder; stressor; synaptogenesis; tool

PROJECT SUMMARY/ABSTRACT Corticotropin-releasing hormone (CRH) expressing neurons in the hypothalamus are critical regulators of the neuroendocrine stress response. CRH neurons integrate stress-related neural inputs and, as part of the hypothalamic-pituitary-adrenal (HPA) axis, induce the release of ACTH and, ultimately, glucocorticoids (cortisol). The development of CRH neurons is of great biomedical interest, as developmental vulnerabilities of CRH neurons contribute to stress-associated disorders such as anxiety and depression. It is, therefore, critical to identify the molecular and cellular mechanisms mediating the development of CRH neurons and determine how developmental changes affect stress response. Using zebrafish, which are genetically accessible and optically translucent, we found that DSCAML1 deficiency impaired the developmental cell death of CRH neurons and caused hyperactivation of the HPI axis (the zebrafish analog of the HPA axis). Given that DSCAML1 is known to mediate intercellular interactions, we hypothesize that proximity-based and synaptic interactions in CRH neurons trigger developmental cell death, which tunes the activity of the neuroendocrine stress response system. To test this, we propose the following aims. In Aim 1, we will test whether proximity-based interactions promote cell death in CRH neurons. Using the live imaging strength of the zebrafish model, we will examine whether interactions between adjacent CRH neurons promote cell death and determine how varying levels of DSCAML1 modulate the extent of cell loss. In Aim 2, we will test whether synaptic interactions affect CRH neuron cell death. Synaptic activity plays an instructive role in neuronal survival. Given DSCAML1’s known functions in synaptogenesis, we will investigate whether CRH neuron survival is dependent on neuronal activity and how DSCAML1-mediated synaptogenesis controls the excitability of CRH neurons. In Aim 3, we will test how DSCAML1 acts within CRH neurons to trigger cell death and establish HPI-axis activity. Using CRH neuron-specific mutants, we will determine how DSCAML1 functions within CRH neurons and whether DSCAML1’s function in other cell types also contributes to HPI-axis development. In Aim 4, we will test the hypothesis that CRH neuron number tunes HPI-axis activity. While the significance of cell death is widely recognized, the functional impact of CRH neuron cell death has not been explored. We will use genetic tools to increase or decrease CRH neuron number and determine the causal relationship between cell number and HPI-axis activity. Together, these aims will shed light on how intercellular interactions influence CRH neuron cell death and provide a molecular framework for future molecular studies.

项目摘要/摘要 下丘脑中表达促肾上腺皮质激素释放激素（CRH）的神经元是下丘脑中促肾上腺皮质激素释放激素（CRH）的关键调节因子。 神经内分泌应激CRH神经元整合与压力相关的神经输入，并且作为CRH神经元的一部分， 下丘脑-垂体-肾上腺（HPA）轴，诱导ACTH的释放，并最终，糖皮质激素 （皮质醇）。CRH神经元的发育具有巨大的生物医学意义，因为CRH神经元的发育脆弱性是由CRH神经元的发育缺陷引起的。 CRH神经元有助于与压力相关的疾病，如焦虑和抑郁。因此， 确定CRH神经元发育的分子和细胞机制，并确定 发育变化如何影响应激反应使用斑马鱼，这是遗传上可接近的， 光学半透明，我们发现DSCAML 1缺陷损害了CRH的发育性细胞死亡， 神经元，并引起HPI轴（HPA轴的斑马鱼类似物）的过度激活。鉴于 已知DSCAML 1介导细胞间的相互作用，我们假设基于邻近性的和突触性的相互作用是通过细胞间的相互作用来实现的。 CRH神经元的相互作用触发发育性细胞死亡，从而调节神经内分泌的活动。 应激反应系统为了验证这一点，我们提出了以下目标。在目标1中，我们将测试 基于邻近的相互作用促进CRH神经元中的细胞死亡。利用实时成像的优势， 在斑马鱼模型中，我们将研究相邻CRH神经元之间的相互作用是否促进细胞死亡， 确定DSCAML 1的不同水平如何调节细胞损失的程度。在目标2中，我们将测试 突触相互作用影响CRH神经元细胞死亡。突触活动在神经元的活动中起着指导性的作用。 生存鉴于DSCAML 1在突触发生中的已知功能，我们将研究CRH神经元是否 存活取决于神经元的活动以及DSCAML 1介导的突触发生如何控制神经元的活动。 CRH神经元的兴奋性。在目标3中，我们将测试DSCAML 1如何在CRH神经元内作用以触发细胞 死亡并建立HP 1轴活性。使用CRH神经元特异性突变体，我们将确定DSCAML 1 在CRH神经元内的功能，以及DSCAML 1在其他细胞类型中的功能是否也有助于HPI轴 发展在目标4中，我们将测试CRH神经元数量调节HPI轴活动的假设。 虽然细胞死亡的重要性被广泛认识，但CRH神经元细胞死亡的功能影响仍然存在。 没有被探索过。我们将使用遗传工具来增加或减少CRH神经元数量，并确定CRH神经元的数量。 细胞数量和HPI轴活性之间的因果关系。总之，这些目标将阐明如何 细胞间相互作用影响CRH神经元细胞死亡，并为未来研究提供分子框架 分子研究