Long-term effects of lactocrine-deficiency on the global porcine endometrial transcriptome and the microRNA-mRNA interactome at pregnancy day 13

Authors: GEORGE, ASHLEY - Rutgers University; HO, TEH-YUAN - Rutgers University; PRASAD, NRIPESH - Hudsonalpha Institute For Biotechnology; Keel, Brittney; Miles, Jeremy; Vallet, Jeff; BARTOL, FRANK - Auburn University; BAGNELL, CAROL - Auburn University

Submitted to: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2018
Publication Date: 7/10/2018
Citation: George, A.F., Ho, T., Prasad, N., Keel, B.N., Miles, J.R., Vallet, J.L., Bartol, F.F., Bagnell, C.A. 2018. Long-term effects of lactocrine-deficiency on the global porcine endometrial transcriptome and the microRNA-mRNA interactome at pregnancy day 13 [abstract]. In proceedings: Society for the Study of Reproduction 51st Annual Meeting, 10-13 July 2018, New Orleans, LA. p. 23-24. Available: https://www.ssr.org/sites/ssr.org/files/2018_annual_meeting_abstracts_updated.pdf

Interpretive Summary:

Technical Abstract: Through lactocrine mechanisms, bioactive factors are transferred from mother to offspring as a specific consequence of nursing to support development. A large, long-term study in pigs showed that minimal colostrum consumption on the day of birth [postnatal day (PND) 0], reflected by low serum immunoglobulin immunocrit (iCrit) values, was associated with reduced live litter size when the lactocrine deficient piglets reached adulthood. Thus, reproductive performance of female pigs that do not receive sufficient colostrum from birth is permanently impaired. Whether neonatal lactocrine deficiency ultimately affects patterns of uterine endometrial gene expression as a mechanism for reduced litter size is unknown. Therefore, objectives were to identify effects of PND 0 lactocrine deficiency on the porcine endometrial mRNA and microRNA transcriptome during the peri-attachment period of pregnancy (pregnancy day 13). At birth, serum iCrit ratios were used to assign gilts into high (0.115 ± 0.01; n = 8) or low (0.033 ± 0.01; n = 7) iCrit groups. At puberty, following one normal estrous cycle, gilts were mated by artificial insemination. On pregnancy day 13, gilts were euthanized, pregnancy confirmed, and endometrium collected. Total endometrial RNA was extracted and used to create cDNA libraries. Libraries were barcoded individually and paired-end mRNAseq (25 million reads) and microRNAseq (15 million reads) were performed using an Illumina HiSeq 2500. Raw reads were mapped to the Sscrofa 11.1 genome build and mature microRNAs were annotated with miRBase release 21. Differentially expressed mRNAs and microRNAs, based on fold change (= ± 1.5, P < 0.05), were identified with respect to neonatal iCrit groups (high versus low iCrit). Expression of selected genes was validated using quantitative PCR. No differences in ovulation rate, uterine length, uterine wet weight, or embryo recovery were observed on pregnancy day 13 in high compared to low iCrit gilts. However, 1157 endometrial mRNAs were differentially expressed, including 562 genes that decreased and 595 genes that increased in expression in high versus low iCrit gilts. Included were genes involved in prostaglandin signaling, uterine receptivity and remodeling, conceptus attachment, immune response, and membrane transport. Bioinformatic analyses identified neonatally lactocrine-sensitive biological processes at pregnancy day 13 including immune response, extracellular matrix remodeling, and cell transport. Six differentially expressed endometrial microRNAs were identified, including miR-129a-3p, miR-7135-5p, miR-371-5p, miR-338, miR-365-5p, and miR-144. Their expression was increased in high versus low iCrit gilts. Integrated microRNA-mRNA analyses, conducted in silico, predicted that five of the six differentially expressed endometrial microRNAs were likely to target 62 of the 1157 differentially expressed mRNAs. Predicted microRNA-mRNA interactions were associated with biological processes similar to those observed for mRNAseq data alone, including those related to development and regulation of cellular functions, such as cell motility. Results indicate that lactocrine deficiency from birth has long-term consequences for endometrial function as reflected by changes in the endometrial transcriptome during early pregnancy. Effects of insufficient colostrum consumption on endometrial function may contribute to the previously observed reduced litter size in adulthood. [Support: USDA-NIFA 2013-67016-20523; NSF-EPS-158862.