Project description:Horse-specific genes are not readily identified from available equine EST/cDNA resources due to relatively limited coverage. In addition, equine gene sets predicted in silico by Ensembl and NCBI will not identify horse specific genes since they rely on homology-based projection of gene structure annotation from other species. In this study, RNA-seq of 8 equine RNA samples representing 6 distinct tissues was performed and used to improve and refine equine gene structure annotation. The samples and RNA were collected as part of the related study E-GEOD-21925 and are described in Coleman et al 2010. Anim Genet 41 Suppl 2: 121-30 (PMID: 21070285). The RNA from these samples was re-sequenced in this experiment. The tissues were i). the articular cartilage and synovial membrane samples from a 3-year-old male pony. The left carpal joints received four LPS injections (0.5 ng) over 8 days, while the right carpal joints received control injections of PBS. ii) A cerebellum sample was collected from a 2-year-old female thoroughbred. iii) A testis sample from a 4-year-old thoroughbred. iv) A placental villous sample collected immediately post-partum from a full-term female thoroughbred foal. v) A whole embryo sample was obtained from a 34-day-old male thoroughbred conceptus. The embryo, cerebellum, testis and placental samples were of apparent normal gross morphology.
Project description:A tissue survey of gene expression was conducted using microarray-based transcriptional profiling to compare equine articular cartilage to 10 other normal adult horse tissues. The ten comparative tissues were bladder, cerebellum, kidney, liver, lung, lymph node, muscle, placental villous, spleen, and testis.
Project description:A tissue survey of gene expression was conducted using microarray-based transcriptional profiling to compare equine articular cartilage to 10 other normal adult horse tissues. The ten comparative tissues were bladder, cerebellum, kidney, liver, lung, lymph node, muscle, placental villous, spleen, and testis. Messenger RNA transcriptome comparisons were conducted between equine articular cartilage and ten other body tissues using a 9413 element equine-specific cDNA microarray and a two-color dye-swap experimental design. After scanning, the median intensities adjusted for background were entire chip Lowess-normalized for each individual slide. Quantile regression was used to estimate the conditional quantile of the M and A log ratios given the observed average log intensity. Briefly, a nonparametric approach was used to reveal the relationship between percentiles of M and A, where M is log2 (R/G) and A is 0.5 log2 (RG) with R representing expression in articular cartilage and G representing expression in the comparative tissue. The quantile regression was fit using a B-spline with 5 fixed nodes. The 1st, 5th, 10th, 20th, 50th, 80th, 90th, 95th, and 99th conditional quantiles were estimated. For each observed gene intensity in a given tissue comparison, the normal quantile was used as the cartilage-specificity in place of the corresponding estimated regression quantile.
Project description:The equine chorioallantois (CA) undergoes complex physical and biochemical changes during labor. However, the molecular mechanisms controlling these changes are still unclear. Therefore, the current study aimed to characterize the transcriptome of equine CA during spontaneous labor and compare it to that of normal preterm CA. Placental samples were collected postpartum from mares with normal term labor (TL group, n=4) and from preterm not in labor mares (330 days GA; PTNL group, n=4). Our study identified 4137 differentailly expressed genes (DEGs) (1820 upregulated and 2317 downregulated) in CA during TL as compared to PTNL. TL was associated with the upregulation of several pro-inflammatory mediators (MHC-I, MHC-II, NLRP3, CXCL8, and MIF). Also, TL was associated with the upregulation of matrix metalloproteinase (MMP1, MMP2, MMP3, and MMP9) with subsequent extracellular matrix degradation and apoptosis, as reflected by upregulation of several apoptosis-related genes (ATF3, ATF4, FAS, FOS, and BIRC3). In addition, TL was associated with downregulation of 21 transcripts coding for collagens. The upregulation of proteases, along with the downregulation of collagens, is believed to be implicated in separation and rupture of the CA during TL. Additionally, TL was associated with downregulation of transcripts coding for proteins essential for progestin synthesis (SRD5A1 and AKR1C1) and angiogenesis (VEGFA and RTL1), as well as upregulation of prostaglandin synthesis-related genes (PTGS2 and PTGES), which could reflect the physiological switch in placental endocrinology and function during TL. In conclusion, our findings revealed the equine CA gene expression signature in spontaneous labor at term, which improves our understanding of the molecular mechanisms triggering labor.
Project description:We have characterized miRNAs associated with equine seminal exosomes, and identified seminal exosomes eca-mir-128 to be specifically downregulated during equine arteritis virus long-term persistent infection in the reproductive tract of the stallion
Project description:The influence of genetics on DNA methylation (DNAme) variation is well documented, yet confounding from population stratification is often unaccounted for in DNAme association studies. Existing approaches have been developed to address confounding by population stratification by directly using DNAme data, but have not been validated in additional human populations or tissues, such as the placenta. Results: To aid future placental DNAme studies in assessing population stratification, we developed an ethnicity classifier, PLANET (placental elastic net DNAme ethnicity classifier), on combined Infinium Human Methylation 450k BeadChip array (HM450k) data from placental samples. We used data from five North American cohorts from private and public repositories (n = 509) and show that PLANET can not only accurately predict (accuracy = 0.9379, kappa = 0.8227) major classes of self-reported ethnicity/race (African: n = 58, Asian: n = 53, Caucasian: n = 389), but can also produce probabilities that are highly correlated with genetic ancestry inferred from genome-wide SNP (>2.5 million SNP) and ancestry informative markers (n=50) data. We found that PLANET’s ethnicity classification relies on 1860 DNAme microarray sites, and over half of these were also linked to nearby genetic polymorphisms (n=955). Lastly, we found our placental-optimized method outperforms existing approaches in assessing population stratification in our placental samples from individuals of Asian, African, and Caucasian ethnicities. Conclusion: PLANET outperforms existing methods and heavily relies on the genetic signal present in DNAme microarray data. PLANET can be used to address population stratification in future placental DNAme association studies, and will be especially useful when ethnicity information is missing and genotyping markers are unavailable.