Signaling mechanisms of the pro Brain Derived Neurotrophic Factor (proBDNF) and the prodomain BDNF (pBDNF) in neurons

神经元中前脑源性神经营养因子 (proBDNF) 和前结构域 BDNF (pBDNF) 的信号传导机制

• 批准号: RGPIN-2021-02498
• 负责人: Gibon, Julien
• 金额: $ 2.19万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761649
• 关键词: Signaling; mechanisms; pro; Brain; Derived

Summary of Research: Neurons are excitable cells that can communicate with other cells via electrical impulses, known as action potential. Neuronal firing activity is necessary to encode messages related to memory and attention. I study a neuronal pattern of activity called "persistent firing" in the brain. This activity refers to the property of neurons to sustain their activity while no stimulus is present and it is an essential mechanism for short-term memory. This pattern of activity must be tightly regulated to avoid hyperexcitability and to ensure that we memorize newly learned information. We need to understand how neuronal firing activity is regulated to understand how our brain functions. My long-term career goal is to elucidate cellular and molecular mechanisms regulating neuronal activity related to short-term memory. A hypothesis I test is that a group of secreted factors, known as proneurotrophic factors regulate neuronal firing pattern. To test this, I will employ electrophysiology, calcium imaging and behavioural studies in mice. My research will lead to new knowledge about the role of proneurotrophic factors on neuronal activity related to short-term memory, and new discoveries about the mechanism of action of these factors on neurons. Because we know almost nothing about the regulation of persistent firing, I anticipate that my research will have a significant impact on other laboratories studying the mechanisms of memory. I will focus on two short-term objectives to fill several gaps of knowledge: Objective 1) To elucidate the cellular and molecular mechanisms of action of the proneurotrophins proBrain Derived Neurotrophic Factor (proBDNF) on cortical neurons, with a specific attention on neuronal synaptic activity. I will test four non-mutually exclusive hypotheses. H1) proBDNF inhibits the activation of muscarinic receptors. H2) proBDNF inhibits TRPC4 and TRPC5 channels in cortical neurons. H3) proBDNF inhibits voltage-gated calcium channel (VGCC) in cortical neurons. H4) proBDNF promotes the hyperpolarization of cortical neurons via the opening of potassium channels. Objective 2) To characterize in detail the effect of a peptide resulting from the cleavage of the proBDNF on neuronal activity related to short term memory and attention. In physiological conditions the proneurotrophin proBDNF is cleaved into two entities: a peptide pBDNF and the mature BDNF. 20% of the human population carries a mutated form of the pBDNF known as pBDNFMet66. The exact functions of the standard form and the mutated form of these peptides are largely unknown. Over the next five years, I propose a series of experiments to better characterize the effect of the pBDNFMet66 on synaptic activity and persistent firing in cortical neurons. New data and knowledge obtained from Objective 1 and 2 will have a significant impact on the neurotrophin field and will considerably increase our understanding of mechanisms underlying memory formation.

研究摘要：神经元是可兴奋的细胞，可以通过电脉冲（称为动作电位）与其他细胞进行通信。神经元放电活动对于编码与记忆和注意力相关的信息是必要的。我研究大脑中一种称为“持续放电”的神经元活动模式。这种活动是指神经元在没有刺激的情况下维持其活动的特性，是短期记忆的重要机制。这种活动模式必须受到严格控制，以避免过度兴奋并确保我们记住新学到的信息。我们需要了解神经元放电活动是如何调节的，才能了解我们的大脑如何运作。我的长期职业目标是阐明调节与短期记忆相关的神经元活动的细胞和分子机制。我测试的一个假设是一组被称为前神经营养因子的分泌因子调节神经元放电模式。为了测试这一点，我将采用电生理学、钙成像和小鼠行为研究。我的研究将带来关于前神经营养因子对与短期记忆相关的神经元活动的作用的新认识，以及这些因子对神经元作用机制的新发现。因为我们对持续放电的调节几乎一无所知，所以我预计我的研究将对其他研究记忆机制的实验室产生重大影响。我将重点关注两个短期目标，以填补几个知识空白： 目标 1) 阐明前神经营养蛋白原脑源性神经营养因子 (proBDNF) 对皮质神经元的作用的细胞和分子机制，特别关注神经元突触活动。我将测试四个非互斥的假设。 H1) proBDNF 抑制毒蕈碱受体的激活。 H2) proBDNF 抑制皮质神经元中的 TRPC4 和 TRPC5 通道。 H3) proBDNF 抑制皮质神经元中的电压门控钙通道 (VGCC)。 H4) proBDNF 通过钾通道的开放促进皮质神经元的超极化。 目标 2) 详细表征 proBDNF 裂解产生的肽对与短期记忆和注意力相关的神经元活动的影响。在生理条件下，前神经营养蛋白 proBDNF 被裂解成两个实体：肽 pBDNF 和成熟 BDNF。 20% 的人群携带 pBDNF 的突变形式，称为 pBDNFMet66。这些肽的标准形式和突变形式的确切功能在很大程度上是未知的。在接下来的五年中，我提出了一系列实验，以更好地表征 pBDNFMet66 对皮质神经元突触活动和持续放电的影响。 从目标 1 和 2 获得的新数据和知识将对神经营养蛋白领域产生重大影响，并将大大增加我们对记忆形成机制的理解。