REGULATION OF HYPOTHALAMIC SIGNALING BY RGS4 PROTEIN

描述(申请人摘要)：这份提案将考察 调节性G蛋白信号转导蛋白(RGS)在调节G蛋白中的作用 体内的连锁信号转导。Rgs蛋白是一个新的蛋白质家族 这增加了与G-α亚基结合的GTP的水解度，并降低了 激活第二信使系统。因此，RGS水平的变化 蛋白质可能介导G反应性的增加或减少 蛋白质偶联受体。我们已经证明了其中一个的过度表达 特定的RGS蛋白，RGS4，可以诱导一个成员的脱敏 5-HT2受体家族在培养细胞中的表达。然而，目前还不知道是否 RGS4蛋白在哺乳动物体内对5-HT2受体也有同样的作用。 反义寡核苷酸策略将被用来检验这一假设 RGS4蛋白调节下丘脑中的5-HT2A受体信号。我们 将测试5-HT2a受体在下丘脑的适应性调节 室旁核，因为它含有丰富的RGS4蛋白 和5-HT2A型受体，5-HT2A型受体在这个核团中可以脱敏或 通过几种治疗变得超级敏感，因为荷尔蒙对 激动剂治疗可作为受体信号转导的灵敏手段。 下丘脑。我们将使用反义寡核苷酸策略来减少 RGS4蛋白水平对1)引起信号超敏和2) 减轻慢性应激引起的5-HT2A信号转导的脱敏作用 用5-HT2A/2C激动剂DOI治疗。最后，我们的初步数据显示 氟西汀诱导5-HT2a时RGS4蛋白表达降低 感受器超敏。我们的研究已经排除了几种可能性 机制，并导致假设RGS4水平的下降 蛋白质可以调节这种超敏反应。因此，我们将研究 RGS4蛋白还原的时程对应关系 氟西汀诱导的5-HT2a受体超敏反应及其表达。这个 拟议的研究结果将为我们提供新的视角来了解 活体中的RGS蛋白以及5-HT2A受体系统的调控机制。 鉴于G蛋白信号在哺乳动物大脑中的重要性，它是必不可少的 了解RGS蛋白的调控。因为它的突出作用 5-HT2A受体在神经精神障碍的病因学中起作用， 理解RGS对5-HT2A信号适应性变化的调节 蛋白质将为治疗干预的新靶点奠定基础 治疗这些疾病。

DESCRIPTION (Applicant's abstract): This proposal will examine the role that regulatory G protein signaling (RGS) proteins play in modulating G-protein linked signal transduction in vivo. RGS proteins are a novel family of proteins that increase the hydrolysis of GTP bound to the G-alpha subunit and reduce the activation of the second messenger system. Thus, changes in the levels of RGS proteins may mediate increases or decreases in the responsiveness of G protein-coupled receptors. We have demonstrated that overexpression of one particular RGS protein, RGS4, can induce desensitization of one member of the 5-HT2 receptor family in cells in culture. However, it is not known whether RGS4 protein has the same effect on 5-HT2 receptors in mammalian brain in vivo. Antisense oligodeoxynucleotide strategies will be used to test the hypothesis that RGS4 protein regulates 5-HT2A receptor signaling in the hypothalamus. We will test the regulation of 5-HT2A receptor adaptation in the hypothalamic paraventricular nucleus, because it contains abundant levels of RGS4 protein and 5-HT2A receptors, 5-HT2A receptors in this nucleus can be desensitized or become supersensitive with several treatments, and because hormone responses to agonist treatment can be used as a sensitive measure of receptor signaling in the hypothalamus. We will use antisense oligonucleotide strategies to reduce the levels of RGS4 protein to 1) cause supersensitivity of signaling and 2) attenuate the desensitization of 5-HT2A signal transduction, induced by chronic treatment with the 5-HT2A/2C agonist DOI. Lastly, our preliminary data suggest that RGS4 protein expression is decreased during fluoxetine-induced 5-HT2A receptor supersensitivity. Our studies have ruled out several possible mechanisms and have led to the hypothesis that a decrease in the levels of RGS4 proteins could mediate this supersensitivity. Thus, we will examine the correspondence between the time course of the reduction in RGS4 protein expression and of fluoxetine-induced 5-HT2A receptor supersensitivity. The results of the proposed studies will provide new insight into the function of RGS proteins in vivo, and the mechanisms regulating 5-HT2A receptor systems. Given the importance of G protein signaling in mammalian brain, it is essential to understand the regulation of RGS proteins. Because of the prominent role that 5-HT2A receptors play in the etiology of neuropsychiatric disorders, understanding the regulation of adaptive changes in 5-HT2A signaling by RGS proteins will lay the foundation for new targets for therapeutic intervention for these disorders.