Project description:Most dairy cows suffer uterine microbial contamination postpartum. Persistent endometritis often develops, associated with reduced fertility. We used a model of differential feeding and milking regimes to produce cows in differing negative energy balance (NEB) status in early lactation. We used Affymetrix GeneChipM-CM-^R Bovine Genome Array to investigate the global gene expression underlying negative energy balance and to identify the significantly differentially expressed genes during this process. We investigate the differences of gene expression profiles in uterine endometrial tissues between the cows with mild and severe negative energy balance.
Project description:Background: Physiological inflammation of the uterus postpartum is essential for the reparative processes of involution after calving. In the majority of cows, this inflammation is resolved and homeostasis is restored. However, in a significant subset, inflammation persists and contributes to tissue damage, pathology and subfertility. Transcriptomic differences of immune genes between cattle that resolve inflammation and those that develop uterine disease have been detected as early as 7 days postpartum (DPP) suggesting that the host immune response plays an important role in disease outcome. Results: Here, we extensively characterise the immune response at the transcriptomic level in endometrial epithelial cells from post-partum dairy cows phenotyped for both clinical and sub-clinical forms of uterine disease. We address the hypothesis that excessive expression of endometrial inflammatory molecules contributes to development of endometritis. Classification of cattle (n=112) as healthy or with uterine disease (purulent vaginal discharge; PVD and cytological endometritis; CYTO) was based on vaginal mucus score and >18% polymorphonuclear cell infiltrate into the endometrium at 21 DPP. RNA-seq analysis of endometrial epithelial cells collected using cytobrushes identified differential expression of 294 genes (FDR <0.05) between cows that subsequently resolved inflammation (n=10) and those that developed disease (n=20). Pathway over-representation analysis of differentially expressed genes (DEG) identified significant changes in immune-related pathways, including the NOD-like receptor signalling pathway, cytokine-cytokine receptor interaction pathway and the Toll-like receptor signalling pathway which were up-regulated in cattle that subsequently developed disease. The majority of the DEG were upregulated in cows that developed PVD, and included all genes upregulated in CYTO cows, suggesting a core inflammatory gene signature early post-partum contributes to the onset of uterine disease. This inflammatory signature was validated by qPCR in an independent group of cows (n=56) and included upregulation of pro-inflammatory genes (including TLR2, TLR4, NLRP3, IL1A, IL1B, IL8, and S100A8) at day 7 postpartum in cows that failed to resolve inflammation. Conclusions: Despite a large amount of inter-animal heterogeneity, these results suggest that excessive activation and inappropriate regulation of the inflammatory response early postpartum is a key feature of the subsequent development of uterine disease. Keywords: Endometritis, Inflammation, Transcriptome, Next generation sequencing, Dairy cattle, Uterine involution, Immune response
Project description:Most dairy cows suffer uterine microbial contamination postpartum. Persistent endometritis often develops, associated with reduced fertility. We used a model of differential feeding and milking regimes to produce cows in differing negative energy balance (NEB) status in early lactation. We used Affymetrix GeneChipÒ Bovine Genome Array to investigate the global gene expression underlying negative energy balance and to identify the significantly differentially expressed genes during this process.
Project description:Pregnancy induces changes in the transcriptome of the bovine endometrium from 15 days after insemination. However, pregnancy is less likely to occur if cows had a postpartum bacterial infection of the uterus. We hypothesized that uterine bacterial infection alters the endometrial transcriptomic signature of pregnancy. To examine the endometrial transcriptomic signature of pregnancy, cows were inseminated 130 days after intrauterine infusion of pathogenic bacteria and endometrium was collected 16 days later for RNA sequencing. We found 171 pregnancy regulated genes in cows 146 days after bacterial infection. When comparing our findings with three previous studies that described the endometrial transcriptomic signature of pregnancy in healthy cows, 24 genes were consistently differentially expressed in pregnancy, including MX1, MX2 and STAT1. However, 12 pregnancy regulated genes were only found in the endometrium of healthy cows, including ISG15 and TRANK1. Furthermore, 28 pregnancy regulated genes were only found in the endometrium of cows following bacterial infection and these were associated with altered iNOS, TLR, and IL-7 canonical signaling pathways. Although 94 predicted upstream regulators were conserved amongst the studies, 14 were found only in the endometrium of pregnant healthy cows, and 5 were found only in cows following bacterial infection, including AIRE, NFKBIA, and DUSP1. In conclusion, there were both consistent and discordant features of the endometrial transcriptomic signature of pregnancy 146 days after intrauterine bacterial infusion. These findings imply that there is an essential transcriptomic signature of pregnancy, but that infection induces long term changes in the endometrium that affect the transcriptomic response to pregnancy.