Farah Eshak
Research Mentor: Cristina Saenz de Miera Patin
Mentor Department: Molecular and Integrative Physiology, Medicine
Author(s): Farah Eshak, Cristina Sáenz de Miera Patín
Session: Session 2 (10:00 AM – 10:50 AM)
Presentation Type: Poster 55
Abstract
The hypothalamus is a brain region that integrates environmental signals to regulate metabolism, circadian rhythm, and hormone release. Photoperiod, or day length during gestation, affects these functions and is communicated to the developing fetus through the hormone melatonin. Prenatal photoperiod is hypothesized to influence hypothalamic development in a maternal melatonin-dependent manner. However, the specific gene networks and developmental pathways through which melatonin acts during development have not been characterized. The goal of this study is to describe the melatonin-sensitive developmental pathways in melatonin-proficient mice. We compared single-cell RNA-sequencing data from newborn MSM mice, a novel mouse model that produces melatonin and shows physiological responses to it, to CBA mice, which do not show responses to photoperiod, and to C57, which do not produce melatonin. We performed gene expression and pathway analysis of tanycytes, specialized ependymal cells in the hypothalamus, using iPathwayGuide to identify patterns that were unique to MSM mice. Additionally, we quantified cell proliferation of MSM mice in the arcuate nucleus, an area in the hypothalamus that regulates hormone signaling, using the cell proliferation maker 5-ethynyl-2-deoxyuridine (EdU) at embryonic days (E)16, 18, and 19 to assess timing of hypothalamic development. We found consistent changes in metabolic and neuroendocrine pathways in MSM mice, including glycolysis/gluconeogenesis and ligand-receptor interactions, compared to the other strains of mice. Additionally, EdU quantification revealed that there is significantly higher proliferation activity in the arcuate nucleus at E16 compared to E18-19 which indicates a developmental decline in cell birth. This suggests that MSM have similar developmental timing, but different biological processes in tanycytes at birth compared to other mice strains. This could provide insight into how prenatal photoperiod influences hypothalamic development in melatonin-producing mice.
