Impact of seasonality, storage of semen, and sperm head-shape on whole tissue methylation and expression of methylation responsive candidate genes in swine placenta and fetal livers from summer and winter breedings

Authors: Rempel, Lea; KRAUTKRAMER, MEGAN - University Of Wisconsin; PARRISH, JOHN - University Of Wisconsin; Miles, Jeremy

Submitted to: Molecular Reproduction and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2019
Publication Date: 4/1/2019
Publication URL: https://handle.nal.usda.gov/10113/6471151
Citation: Rempel, L.A., Krautkramer, M.M., Parrish, J.J., Miles, J.R. 2019. Impact of seasonality, storage of semen, and sperm head-shape on whole tissue methylation and expression of methylation responsive candidate genes in swine placenta and fetal livers from summer and winter breedings. Molecular Reproduction and Development. 86(4):465-475. https://doi.org/10.1002/mrd.23125.
DOI: https://doi.org/10.1002/mrd.23125

Interpretive Summary: Epigenetics is the influence of environmental factors that can alter the DNA structure, without altering the DNA sequence, leading to production or inhibition of gene products. Environmental factors include such things as; diet, stress, or season. Seasonality can have negative impacts upon reproductive performance in swine. ARS scientists along with University of Wisconsin researchers, determined the epigenetic influence of; season of semen collection, difference in sperm head shape change, use of cooled semen versus cryopreserved semen, and breeding season on the methylation activity and expression of methylation responsive genes in the placenta and fetal livers at 45 days pregnancy. Seasonality and preparation of semen (male contribution) had a greater influence on the epigenetics of the placenta. While breeding season (female contribution) was more impactful upon the epigenetics of fetal livers and gene expression. These data provide basic novel evidence for the influence of season on epigenetic traits in swine.

Technical Abstract: Epigenetics includes the study of external factors that can influence the expression of genes by altering accessibility of DNA through methylation. To investigate the epigenetic influence of: season, sperm head shape, and semen storage on placental and fetal tissues, pregnancies were generated in the summer or winter using boar semen: from either least or most sperm head shape change, collected during cool or warm seasons, and stored as cooled-extended or cryopreserved. Lowest (P < 0.05) ratios of 5-methylcytosine to 5-hydroxymethylcytosine activity (5mC:5hmC) in fetal liver was from summer breedings and in placental tissues from winter breedings. Relative expression of placental CDH1 tended (P < 0.10) to be greater in placenta generated from cryopreserved semen or semen collected during cool periods. Relative expression of placental GNAS was affected (P < 0.05) by the interaction of breeding and semen collection seasons. Cryopreserved semen increased (P < 0.05) placental relative expression of GNAS. Placental MEST and RHOBTB3 tended (P < 0.10) to have greater relative expression from pregnancies generated using semen collected during cool periods used during winter breedings. Within fetal liver relative expression of GNAS and HGF was greater (P < 0.05) from winter breedings and CDH1 was influenced (P < 0.05) by the interaction of breeding season and sperm head shape change. Seasonality of semen collection, breeding, and effect on sperm head shape change had an influence on expression of genes with known differentially methylated regions from embryonic and extraembryonic tissues.