Serotonin (5HT) is hypothesized to be a contributor to developmental programming that results in increased risk for childhood and adult-onset mental illnesses. This may occur through the capacity of 5HT to serve as a modulator of processes that include cell proliferation, migration and circuit wiring. Until recently, it was thought that 5HT sources impacting brain development arose from maternal transport of 5HT to the fetus, or from raphe neurons in the brainstem of the fetus. We recently reported that 5HT during pregnancy does not arise from the mother, but rather is synthesized in the human and mouse placenta from maternally-derived tryptophan. Moreover, 5HT accumulates selectively in the fetal forebrain from e10.5-e15.5, but not the hindbrain. These data collectively suggest that developing circuits involved in mediating mood and emotion are sensitive to extraembryonic 5HT during initial ontogeny, which could be impacted by both genetic and environmental disturbances that are known to increase risk for mental illnesses. Specifically, because the developing fetus and placenta are genetically identical, the polymorphisms impacting the 5HT system that are associated with increased risk for mental health-related psychiatric disorders, as well as adverse environmental stressors, could be impacting both organs. The relative contributions of placental and fetal 5HT sources to long-term outcome of offspring are unknown, and will be explored in Project 2, Influence of Placental Serotonin on Neural Development and Behavior. Here, a strategy of selective genetic manipulation of 5HT in the placenta is advanced. The proposed studies take advantage of a placenta-specific promoter of the CYP19 gene, driving Cre expression, only in the placenta, for deleting genes that are engineered to have LoxP sites.
In Aims 1 and 2, the rate-limiting enzyme for 5HT synthesis in the placenta, tryptophan hydroxylase 1, or the principle metabolic enzyme, monoamine oxidase A, will be deleted. The impact of either eliminating or greatly increasing placental 5HT on forebrain and hindbrain neurochemistry and receptor development and basic forebrain patterning will be examined using neurochemical, bioanalytical and molecular neuroanatomical approaches overseen by the Conte cores. As an additional approach, the disruption of the 5HT transport via deletion of placental serotonin transporter (SERT) will be achieved with development of a new floxed SERT animal model that will be generated in the context of Project 3. The enduring influence of genetically altered placental 5HT on emotional regulation will be examined in Aim 3. The studies will, for the first time, define the placental extraembryonic contributions of 5HT to the assembly and tuning of central neurochemical systems and impact on basic developmental processing that are sensitive to 5HT signaling prenatally.

Public Health Relevance

The research focuses on the role of placental serotonin levels on brain development. Disruption of serotonin prenatally relates to a growing body of evidence that subtle, deleterious effects on the fetus as it develops could lead to a lifetime of chronic mental health problems, including anxiety disorders, learning and emotional disabilities and depression.

National Institute of Health (NIH)
Specialized Center (P50)
Project #
Application #
Study Section
Special Emphasis Panel (ZMH1)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Vanderbilt University Medical Center
United States
Zip Code
Ulbricht, Randi J; Emeson, Ronald B (2014) One hundred million adenosine-to-inosine RNA editing sites: hearing through the noise. Bioessays 36:730-5
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
Jackson, Chad R; Capozzi, Megan; Dai, Heng et al. (2014) Circadian perinatal photoperiod has enduring effects on retinal dopamine and visual function. J Neurosci 34:4627-33
Hood, Jennifer L; Morabito, Michael V; Martinez 3rd, Charles R et al. (2014) Reovirus-mediated induction of ADAR1 (p150) minimally alters RNA editing patterns in discrete brain regions. Mol Cell Neurosci 61:97-109
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
Ye, R; Carneiro, A M D; Airey, D et al. (2014) Evaluation of heritable determinants of blood and brain serotonin homeostasis using recombinant inbred mice. Genes Brain Behav 13:247-60
Anastasio, Noelle C; Stutz, Sonja J; Fox, Robert G et al. (2014) Functional status of the serotonin 5-HT2C receptor (5-HT2CR) drives interlocked phenotypes that precipitate relapse-like behaviors in cocaine dependence. Neuropsychopharmacology 39:370-82
Deneris, Evan S; Hobert, Oliver (2014) Maintenance of postmitotic neuronal cell identity. Nat Neurosci 17:899-907
Shi, Zhiao; Wang, Jing; Zhang, Bing (2013) NetGestalt: integrating multidimensional omics data over biological networks. Nat Methods 10:597-8
Wu, Hsiao-Huei; Levitt, Pat (2013) Prenatal expression of MET receptor tyrosine kinase in the fetal mouse dorsal raphe nuclei and the visceral motor/sensory brainstem. Dev Neurosci 35:1-16

Showing the most recent 10 out of 11 publications