Poster Only Presentation
Concurrent Session 4C - Reproductive Science
Introduction: Maternal age is the greatest determinant of reproductive success. In a mouse model of maternal aging, our lab recently showed that the uterine stroma of aged dams have perturbed genetic expression. Notably, a family of epigenetic modifiers, the peptidylarginine deiminases (PADIs) was significantly upregulated in these aged uteri. This project aims to gain a broader understanding of the role and activity of the PADIs at the feto-maternal interface, specifically in the uterine stroma and trophoblast cells. We hypothesize that histone citrullination via the PADIs contributes to the genetic deregulation in the aging murine reproductive tract.
Methods: Expression and localization of the PADIs will be assessed by qRT-PCR, Western Blot, and immunofluorescence in wild-type and Padi knockout murine trophoblast stem cells and uterine stromal cells. To determine the regulatory action of PADIs and their histone mark citrulline, ChIP and ATAC sequencing will be performed. Finally, wild-type and Padi knockout uterine stromal cells from aged mice will be exposed to a hormone stimulus and their decidualization response will be assessed by qRT-PCR of decidualization markers.
Results: Previous RNA-sequencing data, confirmed by qRT-PCR, shows that PADI2, 3, and 4, but not PADI1 are expressed in trophoblast stem cells, and their expression decreases upon differentiation. Enrichment of citrullinated histones within heterochromatic foci in trophoblast stem cells, suggests a repressive role for citrulline. Finally, knockout lines for Padi2 and Padi3 via the CRISPR-Cas9 system have been successfully generated using trophoblast stem cells.
Conclusion: Given the upregulation of the Padi gene family in the uteri of aged mouse dams, PADI activity could be an underlying cause of the uterine functional decline in aged mice. By characterizing the PADIs in a reproductive context and by studies with knockout lines, we can assess their contribution to the age-related genetic deregulation, and potentially implicate them as a target for aging intervention.