Role of postsynaptic transmitter receptors in influencing presynaptic neurotransmitter identity

突触后递质受体在影响突触前神经递质身份中的作用

• 批准号: 2051555
• 负责人: Nicholas Spitzer
• 金额: $ 79.03万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2051555&HistoricalAwards=false
• 关键词: Role; postsynaptic; transmitter; receptors; influencing

Retrograde signaling to ensure the security of message transmission over long distances was pioneered by the Greeks and the Chinese in the 3rd century B.C. Signal fires at night and smoke signals by day generated on one tower could be seen by observers on a distant tower, who then lit signal fires or generated smoke signals to acknowledge receipt of the signal. Chains of signal towers reliably transmitted signals over long distances. Inclusion of a mechanism for sending a retrograde acknowledgement signal has been important for the security of modern telecommunication. Most studies of the function of synapses in the brain have focused on the mechanisms involved in the flow of information from the presynaptic cell to the postsynaptic cell. This project tests the hypothesis that retrograde signaling from postsynaptic neurotransmitter receptors stabilizes the expression of the anterograde presynaptic neurotransmitter system in African Clawed Frogs (Xenopus laevis). This project will reveal the role of retrograde information signals in regulating the stability of the signaling system and potentially explain neurological or psychiatric disorders specifically associated with defects in the stability of synaptic signaling. This project will also provide advanced research training for undergraduate students and high school students from groups that are currently underrepresented in science.This project tests the role of postsynaptic transmitters in regulating presynaptic transmitter stability. We will determine whether loss-of-function via focal blockade of endogenous acetylcholine receptors by pancuronium or curare results in gradual loss of choline acetyl-transferase (ChAT) in presynaptic motor neurons (MNs) at the larval Xenopus neuromuscular junction (NMJ). Preliminary results show that this is the case, consistent with destabilization of the endogenous transmitter, acetylcholine. Because these MNs normally express the neurotransmitter gamma-aminobutyric acid (GABA) transiently at earlier stages of development, we will also investigate whether ectopic expression of GABA receptors (GABA A receptors alpha, beta and gamma) in myocytes in a gain-of-function experiment during development leads to stabilization of expression of GABA in presynaptic cholinergic MNs at later stages. Preliminary data show that GABA appears in innervating axon terminals and in cell bodies in the spinal cord and co-expression of the MN markers Hb9, ChAT and Lim3 confirms their primary MN identity. In line with the appearance of glutamic acid decarboxylase 67 (GAD67) and the vesicular GABA transporter (VGAT) in these MNs, GABAergic miniature endplate potentials (mEPPs) are recorded from the myocytes. These results are consistent with stabilization of the previously expressed transmitter, GABA. Investigating the mechanism by which postsynaptic transmitter receptors may regulate presynaptic transmitter stability, we will test the role of molecules thought to be involved in forming transsynaptic bridges (Lrp4 and Lfhpl4), that link postsynaptic receptors to presynaptic stabilizing proteins. Preliminary results knocking down the expression of these molecules recapitulates the loss-of-function experiments and blocks the results of the gain-of-function experiments. Receptor-mediated retrograde signaling at the synapse may be an acknowledgment signal for maintaining transmitter expression.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在公元前3世纪，希腊人和中国人开创了逆行信号，以确保长距离消息传输的安全性。夜间发射信号，并在一个塔上产生的烟雾信号被遥远塔上的观察员看到，然后点燃信号发射或产生的烟雾信号，以确认收到信号的接收。信号塔的链条可靠地在长距离内传输信号。包括发送逆行确认信号的机制对于现代电信的安全至关重要。大脑中突触功能的大多数研究都集中在从突触前细胞到突触后细胞的信息流涉及的机制。该项目检验了以下假设：从突触后神经递质受体逆行信号传导稳定非洲爪蛙（Xenopus laevis）中突触前神经递质系统的表达。该项目将揭示逆行信息信号在调节信号系统稳定性方面的作用，并有可能解释与突触信号稳定性方面的缺陷有关的神经系统或精神疾病。该项目还将为本科生和高中生提供高级研究培训，这些研究生目前在科学领域的人数不足。该项目测试突触后发射器在调节突触前发射器稳定性中的作用。我们将确定通过胰腺或Curare对内源性乙酰胆碱受体的局灶性阻塞的功能丧失是否会导致在突触前运动神经元（MNS）中的胆碱乙酰基转移酶（CHAT）逐渐损失。初步结果表明，这种情况与内源性发射器乙酰胆碱的不稳定一致。因为这些MN通常在早期发育阶段暂时表达神经递质γ-氨基丁酸（GABA），我们还将调查是否在稳定稳定性的稳定性稳定性的稳定性中，在肌肉中，GABA受体的异位表达GABA受体（GABA A受体Alpha，beta和Gamma）是否是否在肌肉中的稳定性稳定性。 MN在后期阶段。初步数据表明，GABA出现在神经轴突终端和脊髓中的细胞体中，以及MN标记HB9，CHAT和LIM3的共表达，证实了它们的主要MN身份。与这些MN中的谷氨酸脱羧酶67（GAD67）和囊泡GABA转运蛋白（VGAT）的外观一致，从心肌细胞记录了GABA能微型终板电位（MEPP）。这些结果与先前表达的发射器GABA的稳定相一致。研究突触后发射器受体可以调节突触前发射器稳定性的机制，我们将测试被认为与形成经突触的桥（LRP4和LFHPL4）相关的分子的作用，这些分子将突触后受体与突触后稳定性稳定性稳定蛋白联系起来。击倒这些分子表达的初步结果概括了功能丧失的实验，并阻止了功能获得实验的结果。突触时受体介导的逆行信号可能是维持发射器表达的确认信号。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。