Postnatal diet impact on microRNA expression

Authors: CARR, LAURA - University Arkansas For Medical Sciences (UAMS); ELOLIMY, AHMED - Arkansas Children'S Nutrition Research Center (ACNC); WASHAM, CHARITY - Arkansas Children'S Nutrition Research Center (ACNC); BYRUM, STEPHANIE - Arkansas Children'S Nutrition Research Center (ACNC); BOWLIN, ANNE - Arkansas Children'S Nutrition Research Center (ACNC); RANDOLPH, CHRISTOPHER - Arkansas Children'S Nutrition Research Center (ACNC); MACLEOD, STEWART - Arkansas Children'S Nutrition Research Center (ACNC); YERUVA, LAXMI - Arkansas Children'S Nutrition Research Center (ACNC)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Studies have shown the presence of microRNAs (miRNAs) in porcine, bovine and human milk. In addition, miRNAs present in breast milk are very stable to freeze thaw, RNase treatment, and low pH as they are protected inside exosomes in breast milk. miRNAs are abundantly conserved non-coding small nucleotide molecules found in nearly all species. They are involved in regulating several physiologic and pathologic processes, including immunologic pathways. We have demonstrated better immune response to vaccines in piglets fed with human milk (HM) in comparison to cow's milk formula (MF). The objective of the current study is to determine if breastfeeding versus formula feeding alters miRNAs expression in circulation during the neonatal period and after weaning from the neonatal diet. Two day old piglets were obtained and transferred to the vivarium at Arkansas Children's Nutrition Center and fed either HM or MF until day 21 when they weaned to ad libitum solid diet. Whole blood was collected at 21, 35, and 50 days of age and stored at -80°C. Total RNA was isolated, a cDNA library for miRNA was generated using a Qiagen kit and then sequenced on an Illumina NextSeq 500 platform. miRNA were identified from sequencing data using a pig genome database. Statistical analysis was carried out to identify differential expression of miRNA and significant fold changes (p<0.05) between the diet groups was considered to be relevant. At day 21, MF-fed piglets showed increased expression of 14 miRNAs and decreased expression of 10 miRNAs relative to HM-fed piglets. In the day 50 samples, there were 10 miRNAs that were up regulated and 17 down regulated in MF compared to HM suggesting persistent effect of neonatal diet up to at least day 50. miR-708-5p is seen at both day 21 and day 50 but is initially downregulated in the MF-group and later upregulated in the MF-group compared to the HM-group. Pathway analysis and target gene analysis was conducted and showed that many of the miRNAs have an impact on immune function. We observed differential expression of miRNAs from blood at both days 21 and 50. The numbers of miRNAs altered was higher at day 50, post-weaning from the neonatal diet, in MF group than during neonatal feeding suggesting persistent effect of neonatal diet. The source of miRNAs in circulation need to be evaluated as the piglets were fed the same solid diet. It is possible that miRNAs are released into circulation by different immune cells and the immune cell profile itself is altered in MF-fed relative to HM-fed piglets.