Interleukin-1 (IL-1) Receptor-Mediated Modulation of Serotonin Transporters

描述（由申请人提供）：促炎细胞因子在神经精神疾病发病机制中的作用在过去十年中引起了极大的兴趣。细胞因子也被认为能调节血清素的活性。5-羟色胺转运体（SERT）是抗抑郁药物的主要靶点之一，它支持5-羟色胺的失活和再循环，受到多种信号通路的严格调控，包括促炎细胞因子IL-1和TNF-a刺激的信号通路。我们已经证明IL-1能刺激raphe细胞系和小鼠突触体的SERT活性。我们的初步数据现在表明，外周注射LPS诱导野生型小鼠中枢5-HT摄取急性（1小时）增加，但IL-1R敲除小鼠没有。我们假设突触前IL-1Rs通过调节SERT活性传递局部和全身炎症应激（和其他应激源）。由于IL-1Rs在中枢神经系统中的分布并不局限于中脑神经元及其末端，解剖血清素能调节的贡献将需要限制IL-1的消除。因此，目前的研究目标是产生IL-1R敲除小鼠，利用FloxP/Cre技术进一步开发血清素能神经元特异性IL-1R敲除，并表征这些动物的5-HT稳态和相关行为。我的假设是，删除中5 -羟色胺能神经元中的IL-1受体将消除IL-1 / LPS对中枢SERT活性的影响。这一假设的验证将(1)为进一步研究细胞因子-5HT相互作用提供关键数据；(2)有助于推进我们对疾病综合征范式中出现的调节5HT信号网络对抑郁样特征的贡献的理解。为了实现本提案的目标，我们计划进行以下研究：1。生成floxed IL-1R小鼠；2建立并表征血清素能神经元特异性IL-1R敲除小鼠。该项目的主要目标是在缺乏Cre驱动的情况下，实现IL-1R的一个固定等位基因的种系传播，而不会对天然IL-1R的产生产生固有影响，并最终实现条件IL-1R敲除。总之，这些努力支持阐明促炎细胞因子调节大脑功能和行为的体内机制的长期目标。

DESCRIPTION (provided by applicant): The role of pro-inflammatory cytokines in the pathogenesis of neuropsychiatric disorders has drawn a significant interest over the last decade. Cytokines are also known to modulate serotonergic activity. The 5-HT transporter (SERT), one of the major targets of antidepressants, which supports 5-HT inactivation and recycling, is tightly regulated by multiple signaling pathways including those stimulated by the proinflammatory cytokines IL-1¿ and TNF-a. We have shown that IL-1¿ stimulates SERT activity in a raphe cell line as well as in mouse synaptosomes ex vivo. Our preliminary data now demonstrate that peripheral injection of LPS induces an acute (1hr) increase in central 5-HT uptake in wild type mice but not in IL-1R knockouts. We hypothesizes that a presynaptic IL-1Rs communicates local and systemic inflammatory stress (and other stressors) via modulation of SERT activity. As the distribution of IL-1Rs in the CNS is not limited to the raphe neurons and their terminals, dissecting the contribution of serotonergic modulation will require restricted elimination of IL-1¿ action. Thus, the objectives of the current proposal are to generate IL-1R floxed mice, further develop serotonergic neuron specific IL-1R knockout using FloxP/Cre technologies and to characterize the 5-HT homeostasis and related behaviors in these animals. My hypothesis is that deletion of IL-1 receptors in the raphe serotonergic neurons will eliminate the impact of IL-1¿ / LPS on central SERT activity. The validation of this hypothesis will (1) provide critical data for an enlarged study examining cytokine-5HT interactions and (2) help to advance our understanding towards the contribution of modulated 5HT signaling networks to depression-like traits that emerge in sickness syndrome paradigms. To achieve the goal of this proposal, we plan to conduct the following studies: 1. Generate floxed IL-1R mice; 2 Develop and characterize serotonergic neuron-specific IL-1R knockout mice. The essential goal of this project is to achieve germ-line transmission of a floxed allele of the IL-1R with no inherent impact on native IL-1R production in the absence of a Cre driver, and eventually develop conditional IL-1R knockouts. Together, these efforts support the long-term goal of elucidating in vivo mechanisms through which pro-inflammatory cytokines modulate brain function and behavior. PUBLIC HEALTH RELEVANCE: This project investigates the link between Immunological challenges and a key gene controlling the neurotransmitter serotonin for insights into mechanisms that may impact risk for mood disorders including depression, anxiety and autism. This project specifically investigates the immune mediator Interleukin-1 and its receptor in regulation of the brain serotonin transporter (SERT), a major target for antidepressant medications. These studies seek to develop a novel transgenic mouse model that can address the sensitivity of brain serotonin neurons and SERT to IL-1¿ and establish an experimental framework to more precisely link the immune system to mood regulatory mechanisms.