462: Dysregulation of the peripheral circadian regulator Npas2 leads to altered fetal metabolic pathways in a knockout model

Abstract

regulator Npas2 leads to altered fetal metabolic pathways in a knockout model Derek O’Neil, Hector Mendez-Figueroa, Toni-Ann Mistretta, Chunliu Su, Robert Lane, Kjersti Aagaard Baylor College of Medicine, Translational Biology and Molecular Medicine, Houston, TX, Baylor College of Medicine, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Houston, TX, Texas Children’s Hospital, Pathology, Houston, TX, University of Utah, Pediatrics, Salt Lake City, UT OBJECTIVE: In our non-human primate model of maternal high fat diet exposure, we previously identified the peripheral circadian domain gene Npas2 as a mediator of fetal metabolism which is epigenetically reprogrammed. As circadian activity and metabolic reprogramming is not well understood, we aimed to employ a murine gene knockout model to understand the role of Npas2 in regulating hepatic function throughout the lifespan of mice. STUDY DESIGN: Npas2 KO mice ( / ), Npas2 HET mice ( / ) and Npas2 WT mice ( / ) livers were harvested at day 2 (newborn) and at 25 weeks (adult) of life. Total RNA was extracted from hepatic tissue and converted to cDNA. Labeled cDNA was loaded onto the GeneChip® Mouse Exon 1.0 ST array (n 3/cohort). First pass analysis was performed using the Partek Genomics Suite software and GeneSpring GX 11. Genes meeting statistical and expression thresholds after controlling for multiple comparisons were then processed through Ingenuity Pathway Analysis, GSEA, and GeneSpring pathway analysis software. QPCR was performed on cDNA from newborn and adult Npas2 KO and wt mice to determine gene expression levels of genes pertaining to affected metabolic pathways. RESULTS: We identified 2891 genes that were dysregulated in KO mice compared to wt (F .05, fold-change 1.5 or -1.5). The primary dysregulated pathway in the Npas2 KO was the lipid and fatty acid metabolism pathway. Gene expression of Adra2a, Lpin1, Scd1, Sds, and Upp2 demonstrate significant (p .05) neonatal alterations that do not persist into adult life and revert to wt levels. Fgf1, Gpd1, Grb14, Gulo, and Hmgcs1 demonstrated significant (p .05) alterations in neonatal life that reversed expression levels in adult life. CONCLUSION: Npas2 primarily regulates the lipid and fatty acid metabolism pathway during early murine development. However, compensatory pathways are enacted in adult life, indicating a crucial role of Npas2 during fetal/neonatal development which had previously not been definitively described.