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.

National Institute of Health (NIH)
National Institute of Mental Health (NIMH)
Research Project (R01)
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Study Section
Neurogenesis and Cell Fate Study Section (NCF)
Program Officer
Panchision, David M
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Case Western Reserve University
Schools of Medicine
United States
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Deneris, Evan; Gaspar, Patricia (2018) Serotonin neuron development: shaping molecular and structural identities. Wiley Interdiscip Rev Dev Biol 7:
Spencer, William C; Deneris, Evan S (2017) Regulatory Mechanisms Controlling Maturation of Serotonin Neuron Identity and Function. Front Cell Neurosci 11:215
Carlson, Kaitlin S; Whitney, Meredith S; Gadziola, Marie A et al. (2016) Preservation of Essential Odor-Guided Behaviors and Odor-Based Reversal Learning after Targeting Adult Brain Serotonin Synthesis. eNeuro 3:
Whitney, Meredith Sorenson; Shemery, Ashley M; Yaw, Alexandra M et al. (2016) Adult Brain Serotonin Deficiency Causes Hyperactivity, Circadian Disruption, and Elimination of Siestas. J Neurosci 36:9828-42
Wyler, Steven C; Spencer, W Clay; Green, Noah H et al. (2016) Pet-1 Switches Transcriptional Targets Postnatally to Regulate Maturation of Serotonin Neuron Excitability. J Neurosci 36:1758-74
Wyler, Steven C; Donovan, Lauren J; Yeager, Mia et al. (2015) Pet-1 Controls Tetrahydrobiopterin Pathway and Slc22a3 Transporter Genes in Serotonin Neurons. ACS Chem Neurosci 6:1198-205
Issler, Orna; Haramati, Sharon; Paul, Evan D et al. (2014) MicroRNA 135 is essential for chronic stress resiliency, antidepressant efficacy, and intact serotonergic activity. Neuron 83:344-360
Spoida, Katharina; Masseck, Olivia A; Deneris, Evan S et al. (2014) Gq/5-HT2c receptor signals activate a local GABAergic inhibitory feedback circuit to modulate serotonergic firing and anxiety in mice. Proc Natl Acad Sci U S A 111:6479-84
Ciarleglio, Christopher M; Resuehr, Holly E S; Axley, John C et al. (2014) Pet-1 deficiency alters the circadian clock and its temporal organization of behavior. PLoS One 9:e97412
Deneris, Evan S; Hobert, Oliver (2014) Maintenance of postmitotic neuronal cell identity. Nat Neurosci 17:899-907

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