Epigenetic modifications of white blood cell DNA caused by transient fetal infection with bovine viral diarrhea virus
The impact of late-term fetal bovine viral diarrhea virus (BVDV) transient infections (TI) on fetal growth and methylome was examined by inoculating pregnant heifers with a noncytopathic (ncp) type 2 BVDV suspended in media or media alone (sham-inoculated controls) on day 175 of gestation to generate TI (n=11) and control heifer calves (n=12).  Blood samples were collected at birth. White blood cells (WBC) were separated for DNA extraction.  Fetal infection in calves was confirmed by positive virus serum neutralizing antibody titers at birth and control calves were seronegative. Both control and TI calves were negative for BVDV RNA in WBCs by RT-PCR.   DNA methyl seq analysis of WBC DNA demonstrated 2,349 differentially methylated cytosines (p=0.05) including 1,277 hypomethylated cytosines, 1.072 hypermethylated cytosines, 84 differentially methylated regions based on CpGs in promoters and 89 DMRs based on CpGs in exons of TI WBC DNA compared to controls.  Fetal BVDV infection during late gestation resulted in epigenomic modifications predicted to affect fetal and organ development pathways suggesting potential consequences for postnatal growth and health of TI cattle. Overall design: Reduced-representation bisulfite sequencing (RRBS-Seq ) for five randomly selected newborn calves from heifers that were inoculated with BVDV on day 175 of gestation and five randomly selected newborn calves from heifers that were inoculated with sham media on day 175 of gestation. Jugular vein was collected, and PMBC were collected for DNA analysis.