Title: Genes Encoding for Secreted Proteins Increase During the Pre-Implantation Period of Pregnancy in the Bovine Endometrium and Are Modulated by Progesterone Concentrations In Vivo.
Abstract: In cattle, conceptus elongation is a maternally-driven process that requires secretions from the endometrium; the uterine environment required to initiate this process is established by Day 13 of pregnancy. We hypothesized that genes that encode for secreted proteins on Day 13 contribute to this process and that endometrial expression of these genes would be increased during the pre-implantation period of pregnancy and modulated by progesterone (P4) in vivo. The specific aims were 1) to screen both conceptus and endometrial RNA sequencing (RNAseq) data to identify genes that encode for secreted proteins that are only expressed in the endometrium, 2) to examine the expression of these selected genes in the endometrium as the pre-implantation period of pregnancy progresses, and 3) to determine whether their expression is modulated in models of advanced or delayed post-ovulatory rise in P4 concentrations in vivo. RNAseq data from bovine endometrium and conceptus tissue collected on Day 13 of pregnancy (initiation of conceptus elongation) were subjected to stringent cut off criteria with a minimum of 0.5 transcripts per million detected in four out of five samples. RNAseq detected 14,101 transcripts in the conceptus and 16,325 in the endometrium on Day 13 of pregnancy. Of these expressed transcripts, 1,045 were detected in the conceptus only whereas 3 times more genes were expressed exclusively in the endometrium (3,269). Annotation revealed 49 genes encoding for secreted proteins were detected in the conceptus on Day 13. In contrast, 222 genes encoding for secreted proteins were expressed only in the endometrium. A subset of these genes was analyzed by quantitative real-time PCR (qPCR) in endometrium recovered from the pre-implantation period of pregnancy (Day 7, 10, 13, 16 and 19) as well as from endometrium exposed to low (induced by 3 intramuscular injections of prostaglandin F2a on Day 3, 3.5 and 4 of the estrous cycle) or high (induced by PRID insertion on Day 3) P4 concentrations in vivo. Endometrial tissue was collected on either Day 7 or Day 13 of the estrous cycle and snap frozen in liquid nitrogen for qPCR analysis. The expression of CYP61, LCAT, MUC13, NCDN, NMN, NPNT and TINAGL1 increased in pregnant endometria as pregnancy progressed from Day 13 to 19 (P<0.05). An early increase in P4 concentrations (due to P4 supplementation) lead to an early increase (Day 7) in endometrial expression of LCAT, NPNT, NXPH3 and PLIN2, while an early and sustained increase in expression to Day 13 of PENK was observed (P<0.05). In contrast, heifers with a delay in the post-ovulatory increase in P4, displayed a lower increase in TINAGL1 expression throughout the estrous cycle (P<0.05). We propose that modulation of these genes that encode for secreted proteins that are exclusively expressed in the endometrium on Day 13, some of which are modulated by P4 in vivo, play a critical role in conceptus elongation in cattle. Funded by Science Foundation Ireland.
Publication Year: 2012
Publication Date: 2012-08-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 1
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