Genetic mechanisms controlling serotonergic function across life span

描述（由申请人提供）：本项目旨在研究在整个生命周期中调节5-HT系统功能的遗传机制，并确定这些机制如何影响出生后5-HT调节行为。这些研究的基础是Pet-1依赖性转录程序的发现，该程序调节5-HT调节的行为和新开发的5-HT神经元特异性和时间控制的条件靶向方法。我们的方法已经能够在纯化的5-HT神经元中对5-HT神经元特异性转录机制进行调查，并在生命的任何阶段对多巴胺能基因进行功能研究，并对基因消融进行可靠的空间和时间控制。关于Pet-1控制5-HT神经元发育和最终5-HT调节行为的机制，仍有许多问题没有答案。例如，尽管我们以前的研究表明，Pet-1是协调诱导直接负责5-HT合成、再摄取、自抑制和代谢的基因（Tph 2、AADC、Sert、Vmat 2、Htr 1A、Htr 1B、MaoB）所必需的，但不知道Pet-1的功能是否仅限于这些基因。也不知道Pet-1是否调节不同群体的5-HT神经元中的不同基因组，以及它是否仅仅是多巴胺能基因表达的激活剂，或者它是否可能在5-HT神经元发育期间同时抑制某些基因的表达。虽然我们已经表明，在成年5-HT神经元中需要Pet-1来维持Tph 2和Sert，但对Pet-1指导的转录在基本5-HT神经元功能如5-HT神经元放电和5-HT调制行为中的关键时期知之甚少。我们将调查是否转录调控Pet-1所需的控制5-HT信号在生命的不同阶段，包括新生儿到青少年时期。新生儿期（P5-P20）是一个时期，其中5-HT信号传导已被证明是至关重要的正常成人的情绪行为，而青少年期与5-HT相关的疾病，如精神分裂症和压力相关的情绪障碍的发作相一致。最后，由于缺乏合适的方法，新生儿和成人5-HT神经元中5-HT合成对5-HT调制行为的重要性从未得到充分解决。我们将使用我们的新的时间条件靶向方法来测试特定的假设在行为小鼠的5-HT合成的出生后早期和成年期的要求。总之，我们的新目标将研究Pet-1调控基因的下游网络，内在转录机制的要求，以及在可塑性发育过渡期的5-HT合成，这些过渡期是确定心理健康相关行为的关键时期。 公共卫生相关性：该研究项目将继续阐明Pet-1指导的转录调控机制，这些机制在整个生命周期中控制5-羟色胺系统的功能。我们将确定Pet-1下游网络和Pet-1定向转录在新生儿，青少年和成人阶段的精神疾病相关行为的调节的时间要求。我们还将实施一种新的靶向方法，以确定新生儿和成人血清素合成在行为和生理学中的重要性。

DESCRIPTION (provided by applicant): This project is aimed at investigating the genetic mechanisms that act across lifespan to regulate 5-HT system function and determine how these mechanisms impact postnatal 5-HT modulated behaviors. The basis of these studies is the discovery of a Pet-1 dependent transcriptional program that regulates 5-HT-modulated behaviors and newly developed 5-HT neuron-specific and temporally controlled conditional targeting approaches. Our approaches have enabled an investigation of 5-HT neuron-specific transcriptional mechanisms in purified 5-HT neurons and functional studies of serotonergic genes at any stage of life with reliable spatial and temporal control of gene ablation. Many questions remain unanswered about the mechanisms through which Pet-1 controls 5-HT neuron development and ultimately 5-HT modulated behaviors. For example, although our previous studies have shown that Pet-1 is needed for the coordinate induction of genes (Tph2, AADC, Sert, Vmat2, Htr1A, Htr1B, MaoB) directly responsible for 5-HT synthesis, reuptake, autoinhibition and metabolism it is not known whether Pet-1's function is restricted to these genes. It is also not known whether Pet-1 regulates different sets of genes in different populations of 5-HT neurons and whether it is solely an activator of serotonergic gene expression or whether it, perhaps, also simultaneously represses expression of some genes during the development of 5-HT neurons. Although we have shown that Pet-1 is needed in adult 5-HT neurons for maintenance of Tph2 and Sert the critical periods for Pet-1-directed transcription in essential 5-HT neuron functions such as 5-HT neuron firing and 5-HT modulated behaviors are poorly understood. We will investigate whether transcriptional regulation by Pet-1 is required for control of 5-HT signaling at different stages of life including the neonatal to adolescent period. The neonatal period (P5-P20) is a period in which 5-HT signaling has been shown to be critical for normal adult emotional behaviors while the adolescent period coincides with the onset of 5-HT related disorders such as schizophrenia and stress-related emotional disturbances. Finally, the importance of 5-HT synthesis in neonatal and adult 5-HT neurons for 5-HT modulated behaviors has never been adequately addressed because of the lack of suitable methods. We will use our new temporal conditional targeting approaches to test specific hypotheses about the early postnatal and adulthood requirements for 5-HT synthesis in the behaving mouse. Together, our new aims will investigate the downstream network of Pet-1 regulated genes, the requirements for intrinsic transcriptional mechanisms, and 5-HT synthesis at malleable developmental transition periods that are known to be critical periods for the determination of mental health relevant behaviors. PUBLIC HEALTH RELEVANCE: This research project will continue to elucidate the Pet-1 directed transcriptional regulatory mechanisms that control serotonin system function across life span. We will determine the Pet-1 downstream network and the temporal requirements for Pet-1 directed transcription at neonatal, adolescent and adult stages in the regulation of psychiatric disease relevant behaviors. We will also implement a new targeting approach to determine the importance of neonatal and adult serotonin synthesis in behavior and physiology.