Project description:This study relates to pregnancy outcome after assisted reproduction of fertility-classified cattle. The aim is to investigate how the uterine environment impacts and programs conceptus survival and development. The study found that ripple effects of dysregulated conceptus-endometrial interactions elicit post-elongation pregnancy loss in subfertile animals during the implantation period.
Project description:Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In Study One, 270 predominantly Angus heifers were classified based on fertility using four rounds of serial embryo transfer (ET) to select animals with intrinsic differences in pregnancy loss. In each round, a single in vitro-produced high-quality embryo was transferred into heifers on day 7 post-estrus and pregnancy was determined on days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In Study Two, fertility-classified heifers were resynchronized and bred with semen from a single high fertility bull. Blood samples were collected every other day from days 0 to 36 post-mating. Pregnancy rate was determined on day 28 by ultrasound and tended to be higher in HF (70.4%) and SF (46.7%) than IF (0%) heifers. Progesterone concentrations in serum during the first 20 days post-estrus were not different in non-pregnant heifers and also not different in pregnant heifers among fertility groups. In Study Three, a single in vivo-produced embryo was transferred into fertility-classified heifers on day 7 post-estrus. The uteri were flushed on day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the day 14 endometrial biopsies of pregnant HF, SF and IF heifers (n=5 per group) and analyzed by edgeR robust analysis. There were 26 differentially expressed genes (DEG) in the HF compared to SF endometrium, 12 DEG for SF compared to IF endometrium, and 3 DEG between the HF and IF endometrium. Many of the DEG encoded proteins involved in immune responses and are expressed in B cells. Results indicate that pre-implantation conceptus survival and growth to day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between days 14 and 28 when pregnancy recognition signaling and conceptus implantation must occur for the establishment of pregnancy. Endometrial biopsies were subjected to RNA sequencing from high fertile (HF; n=5), subfertile (SF; n=5) and infertile (IF; n=5) classified heifers on day 14 of pregnancy.
Project description:The aim of this study was to examine the effect of sire fertility status on conceptus-induced changes in the endometrial transcriptome. Holstein Friesian bulls (3 High fertility, HF, 3 Low fertility, LF) were selected from the Irish national population of AI bulls (minimum of 500 inseminations/bull) based on adjusted fertility scores (HF: +4.37% and LF: -12.7%; mean = 0%). To generate elongated conceptuses, Day 7 blastocysts produced in vitro using sperm from these six bulls were transferred in groups of 5-10 to synchronized heifers (n=7 heifers per bull; total 42 heifers). Conceptuses were recovered following slaughter on Day 15 (recovery rate: HF 59.4% vs. LF 45.0%; P<0.05). In parallel, Day 15 endometrial explants were recovered from synchronized cyclic heifers (n=4). Explants from each heifer were co-cultured for 6 h in RPMI medium with (i) nothing, control (ii) 100 ng/ml ovine recombinant interferon tau (IFNT) (iii) a single conceptus from each high fertility bull, or (iv) a single conceptus from each low fertility bull. To minimize variation, explants from the same uterus were used across all treatments, replicated across 4 heifers. After 6 h, explants were snap frozen and stored at -80°C. Extracted mRNA was subjected to RNA-seq (Illumina NextSeq 500) and the resulting data were analyzed through a bioinformatic pipeline with R software.
Project description:Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In Study One, 270 predominantly Angus heifers were classified based on fertility using four rounds of serial embryo transfer (ET) to select animals with intrinsic differences in pregnancy loss. In each round, a single in vitro-produced high-quality embryo was transferred into heifers on day 7 post-estrus and pregnancy was determined on days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In Study Two, fertility-classified heifers were resynchronized and bred with semen from a single high fertility bull. Blood samples were collected every other day from days 0 to 36 post-mating. Pregnancy rate was determined on day 28 by ultrasound and tended to be higher in HF (70.4%) and SF (46.7%) than IF (0%) heifers. Progesterone concentrations in serum during the first 20 days post-estrus were not different in non-pregnant heifers and also not different in pregnant heifers among fertility groups. In Study Three, a single in vivo-produced embryo was transferred into fertility-classified heifers on day 7 post-estrus. The uteri were flushed on day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the day 14 endometrial biopsies of pregnant HF, SF and IF heifers (n=5 per group) and analyzed by edgeR robust analysis. There were 26 differentially expressed genes (DEG) in the HF compared to SF endometrium, 12 DEG for SF compared to IF endometrium, and 3 DEG between the HF and IF endometrium. Many of the DEG encoded proteins involved in immune responses and are expressed in B cells. Results indicate that pre-implantation conceptus survival and growth to day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between days 14 and 28 when pregnancy recognition signaling and conceptus implantation must occur for the establishment of pregnancy.
Project description:The objective is to investigate changes in metabolomics of uterine lumen content of lactating dairy cows associated with the onset of conceptus (embryo and associated membranes) elongation. Lactating dairy cows had estrous cycles synchronized and were subjected to induced ovulation and timed artificial insemination (AI). The day of AI was considered study d 0. On d 15, uteri were flushed by transcervical catheterization and infusion of 20 mL of phosphate buffered solution with 0.1% of polyvinyl acetate. Recovered conceptuses were classified based on morphology/length as ovoid (OV; 1-4 mm), tubular (TUB; 5-19 mm) and filamentous (FIL; 20-85 mm). The first 20 mL infused in the uterus were recovered, placed in conical tubes and centrifuged at 2,000 × g at 4ᵒC. The supernatant was collect, aliquoted and stored at -80ᵒC for later analyses of fluid composition, including measurement of IFN-τ concentration. Cows with no conceptus recovered and no detection of IFN-τ in uterine flushing were considered as nonpregnant (NPREG). The experimental design was then considered a prospective cohort study with 4 independent groups (NPREG, OV, TUB, and FIL). The additional 5th group represents a specific physiological condition of cows within the study and it will be compared to TUB and FIL groups combined, working as a pilot study for future research.
Project description:This study relates to embryo-maternal interaction. The aim was to compare the transcriptome and ability of the ipsilateral and contralateral uterine horns to support preimplantation conceptus survival and growth to Day 14. Although differences in gene expression exist between the endometrium of uterine horns ipsilateral and contralateral to the CL in cattle, they do not impact conceptus survival or length between Days 7 and 14.
Project description:The present studies tested the hypothesis that the elongating ovine conceptus and uterus produces EVs with the potential to mediate conceptus-maternal communication during early pregnancy. In Study One, EVs were purified from uterine luminal fluid (ULF) of day 14 cyclic sheep. The EVs were fluorescently labeled with PKH67 dye and infused into the uterine lumen of pregnant sheep for 6 days using an osmotic pump. On day 14, labeled EVs were observed in the conceptus trophectoderm and uterine epithelia, but not in the uterine stroma or myometrium. In Study Two, day 14 conceptuses were cultured ex vivo for 24 hours and found to release EVs into the culture medium. Isolated EVs from conceptuses were fluorescently labeled with PKH67 and infused into the uterine lumen of cyclic sheep for 6 days using an osmotic pump. On day 14, labeled EVs were observed in the uterine epithelia, but not in the uterine stroma or myometrium. No evidence of EV escape from the uterine lumen was observed by analysis of the ovary and other maternal tissues. Proteomics analysis of the day 14 conceptus-derived EVs identified 231 proteins that were enriched for extracellular space and several protein classes including proteases, protease inhibitors, chaperones and chaperonins. RNA-sequencing of day 14 conceptus-derived EVs detected expression of 512 mRNAs. The top expressed genes were overrepresented in ribosomal functions and components. These studies support the ideas that EVs emanate from both the conceptus trophectoderm and uterine epithelia and are involved in intercellular communication during the establishment of pregnancy. Transcriptional profiles from day 14 conceptus extracellular vesicles isolated from 24 hour conceptus-conditioned culture media (n=3) were generated by sequencing on the Illumina HiSeq 2500 platform.
Project description:The present studies tested the hypothesis that the elongating ovine conceptus and uterus produces EVs with the potential to mediate conceptus-maternal communication during early pregnancy. In Study One, EVs were purified from uterine luminal fluid (ULF) of day 14 cyclic sheep. The EVs were fluorescently labeled with PKH67 dye and infused into the uterine lumen of pregnant sheep for 6 days using an osmotic pump. On day 14, labeled EVs were observed in the conceptus trophectoderm and uterine epithelia, but not in the uterine stroma or myometrium. In Study Two, day 14 conceptuses were cultured ex vivo for 24 hours and found to release EVs into the culture medium. Isolated EVs from conceptuses were fluorescently labeled with PKH67 and infused into the uterine lumen of cyclic sheep for 6 days using an osmotic pump. On day 14, labeled EVs were observed in the uterine epithelia, but not in the uterine stroma or myometrium. No evidence of EV escape from the uterine lumen was observed by analysis of the ovary and other maternal tissues. Proteomics analysis of the day 14 conceptus-derived EVs identified 231 proteins that were enriched for extracellular space and several protein classes including proteases, protease inhibitors, chaperones and chaperonins. RNA-sequencing of day 14 conceptus-derived EVs detected expression of 512 mRNAs. The top expressed genes were overrepresented in ribosomal functions and components. These studies support the ideas that EVs emanate from both the conceptus trophectoderm and uterine epithelia and are involved in intercellular communication during the establishment of pregnancy.
Project description:The objective of the present investigation was to utilize the GeneChip® Porcine Genome Array from Affymetrix possessing 20, 201 unique probe sets to identify differentially expressed genes during rapid trophoblastic elongation and attachment to the uterine surface in the pig. Identification and characterization of conceptus gene expression patterns during rapid trophoblastic elongation and attachment in the pig will provide a better understanding of the events required for successful implantation and embryonic survival.