title: Clinical and subclinical endometritis induced alterations in bovine endometrial transcriptome and miRNome profile.
abstract: BACKGROUND
  Clinical and subclinical endometritis are known to affect the fertility of dairy cows by inducing uterine inflammation. We hypothesized that clinical or subclinical endometritis could affect the fertility of cows by disturbing the molecular milieu of the uterine environment. Here we aimed to investigate the endometrial molecular signatures and pathways affected by clinical and subclinical endometritis. For this, Holstein Frisian cows at 42-60 days postpartum were classified as healthy (HE), subclinical endometritis (SE) or clinical endometritis (CE) based on veterinary clinical examination of the animals and histological evaluation the corresponding endometrial biopsies. Endometrial transcriptome and miRNome profile changes and associated molecular pathways induced by subclinical or clinical endometritis were then investigated using GeneChip® Bovine Genome Array and Exiqon microRNA PCR Human Panel arrays, respectively. The results were further validated in vitro using endometrial stromal and epithelial cells challenged with subclinical and clinical doses of lipopolysaccharide (LPS).
  
  
  RESULTS
  Transcriptome profile analysis revealed altered expression level of 203 genes in CE compared to HE animals. Of these, 92 genes including PTHLH, INHBA, DAPL1 and SERPINA1 were significantly upregulated, whereas the expression level of 111 genes including MAOB, CXCR4, HSD11B and, BOLA, were significantly downregulated in CE compared to the HE animal group. However, in SE group, the expression patterns of only 28 genes were found to be significantly altered, of which 26 genes including PTHLH, INHBA, DAPL1, MAOB, CXCR4 and TGIF1 were common to the CE group. Gene annotation analysis indicated the immune system processes; G-protein coupled receptor signaling pathway and chemotaxis to be among the affected functions in endometritis animal groups. In addition, miRNA expression analysis indicated the dysregulation of 35 miRNAs including miR-608, miR-526b* and miR-1265 in CE animals and 102 miRNAs including let-7 family (let-7a, let-7c, let-7d, let-7d*, let-7e, let-7f, let-7i) in SE animals. Interestingly, 14 miRNAs including let-7e, miR-92b, miR-337-3p, let-7f and miR-145 were affected in both SE and CE animal groups. Further in vitro analysis of selected differentially expressed genes and miRNAs in endometrial stroma and epithelial cells challenged with SE and CE doses of LPS showed similar results to that of the array data generated using samples collected from SE and CE animals.
  
  
  CONCLUSIONS
  The results of this study unraveled endometrial transcriptome and miRNome profile alterations in cows affected by subclinical or clinical endometritis which may have a significant effect on the uterine homeostasis and uterine receptivity.
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Dessie
authors.initials: D
authors.lastname: Salilew-Wondim
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Sally
authors.initials: S
authors.lastname: Ibrahim
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Samuel
authors.initials: S
authors.lastname: Gebremedhn
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany. tesfaye@itw.uni-bonn.de.
authors.forename: Dawit
authors.initials: D
authors.lastname: Tesfaye
authors.affiliation: Clinic for Cattle, University of Veterinary Medicine, 30173, Hannover, Germany.
authors.forename: Maike
authors.initials: M
authors.lastname: Heppelmann
authors.affiliation: Clinic of Reproductive Medicine, Vetsuisse Faculty, University of Zurich, 8057, Zurich, Switzerland.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Bollwein
authors.affiliation: University of Veterinary Medicine, 30173, Hannover, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Pfarrer
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Tholen
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Neuhoff
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Schellander
authors.affiliation: Department of Animal Breeding and Husbandry, Institute of Animal Science, Endenicher Allee 15, 53115, Bonn, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoelker
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics*; D004716:Endometritis / Q000235:genetics / Q000662:veterinary*; D004717:Endometrium / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005298:Fertility; D005786:Gene Expression Regulation; D035683:MicroRNAs / Q000235:genetics*; D058977:Molecular Sequence Annotation; D059467:Transcriptome
chemical_list: D035683:MicroRNAs
keywords: Bovine; Endometritis; Inflammation; Transcriptome; miRNome