The Neurosecretory Protein VGF: Contributions to Pain

描述（由申请人提供）：提议的项目将描述疼痛通路中的一种新的信号系统。VGF（非首字母缩写）是一种类似于嗜铬颗粒蛋白家族的神经分泌蛋白。它在受调节的分泌途径中被分类，并被蛋白水解加工成片段，在刺激时释放。目前，VGF生物活性片段的确切身份及其作用机制尚不清楚。我们的初步研究表明，VGF在神经性和炎症性疼痛模型中迅速上调。此外，我们发现一种vgf衍生的肽（VGF-C30）在脊髓给药后诱导热痛觉过敏。这些发现使我们假设VGF参与了慢性疼痛条件下的疼痛信号传导。该项目的目的是为VGF在慢性疼痛中的作用的深入机制分析奠定基础。特异性目的1将通过以下假设来评估VGF在疼痛通路中的生理相关性：1)VGF衍生的片段在刺激时从感觉神经元释放。在这些实验中，从感觉神经元以去极化依赖的方式释放的VGF片段将使用生化方法（包括质谱法）进行表征。2) VGF- C30的行为效应是受体介导的细胞内信号通路激活的结果。vgf衍生的生物活性分子激活的潜在受体及其信号传导机制完全不清楚。本研究将从药理学和生物化学角度评价VGF-C30在脊髓膜制剂中的结合位点。此外，基于初步证据，我们将探讨丝裂原活化蛋白激酶通路在脊髓VGF-C30信号传导中的作用机制。具体目标2将解决VGF有助于慢性疼痛机制的假设。拟议的研究将采用两种方法来解决这一假设：1)已经建立的VGF敲除小鼠系，以及2)sirna介导的VGF表达敲除。这两种方法的结合将允许全面评估VGF在慢性疼痛的发展和维持中的作用。总之，该项目将研究一种新的信号系统对慢性疼痛机制的贡献。所获得的信息可能使VGF成为慢性疼痛的潜在治疗靶点。该项目将描述疼痛通路中一个新的信号系统：神经分泌蛋白VGF（非首字母缩写）。这些研究将为深入分析VGF在慢性疼痛中的作用机制奠定基础。所获得的信息可能使VGF成为慢性疼痛的潜在治疗靶点。

DESCRIPTION (provided by applicant): The proposed project will characterize a novel signaling system in the pain pathway. VGF (non-acronymic) is a neurosecretory protein similar to the family of chromogranins. It is sorted in the regulated secretory pathway and proteolytically processed into fragments that are released upon stimulation. Currently the precise identity of VGF bioactive fragments and their mechanisms of action are unknown. Our preliminary studies indicate that VGF is rapidly upregulated in models of neuropathic and inflammatory pain. Furthermore, we have found that a VGF-derived peptide (VGF-C30) induces thermal hyperalgesia following spinal administration. These findings have lead us to hypothesize that VGF is involved in pain signaling under conditions of chronic pain. The objective of the proposed project is to establish foundations for in-depth mechanistic analysis of the role of VGF in chronic pain. Specific Aim 1 will evaluate the physiological relevance of VGF in the pain pathway by addressing the following hypotheses: 1) VGF-derived fragments are released from sensory neurons upon stimulation. In these experiments, VGF fragments released from sensory neurons in a depolarization-dependent manner will be characterized using biochemical approaches, including mass spectrometry. 2) The behavioral effects of VGF- C30 are the result of a receptor-mediated activation of an intracellular signaling pathway. The potential receptors activated by VGF-derived bioactive molecules and their signaling mechanisms are completely uncharacterized. The proposed studies will evaluate the binding site(s) of VGF-C30 in spinal cord membrane preparations pharmacologically and biochemically. In addition, based on preliminary evidence, the contribution of mitogen-activated protein kinase pathways to the mechanisms if VGF-C30 signaling in spinal cord will be examined. Specific Aim 2 will address the hypothesis that VGF contributes to mechanisms of chronic pain. The proposed studies will employ two approaches to address this hypothesis: 1) an already established line of VGF knockout mice, and 2) siRNA-mediated knock-down of VGF expression. The combination of these two approaches will allow comprehensive evaluation of the role of VGF in the development and maintenance of chronic pain. In summary, the proposed project will examine the contribution of a novel signaling system to mechanism of chronic pain. The information gained may establish VGF as a potential therapeutic target for chronic pain conditions. The proposed project will characterize a novel signaling system in the pain pathway: the neurosecretory protein VGF (non-acronymic). These studies will lay the foundations for in-depth mechanistic analysis of the role of VGF in chronic pain. The information gained may establish VGF as a potential therapeutic target for chronic pain conditions.