title: Role of microRNAs in controlling gene expression in different segments of the human epididymis.
abstract: BACKGROUND
  The molecular mechanisms implicated in regionalized gene expression in the human epididymis have not yet been fully elucidated. Interestingly, more than 200 microRNAs (miRNAs) have been identified in the human epididymis and could be involved in the regulation of mRNA stability and post-transcriptional expression in this organ.
  
  
  METHODS
  Using a miRNA microarray approach, we investigated the correlation between miRNA signatures and gene expression profiles found in three distinct regions (caput, corpus and cauda) of human epididymides from 3 donors. In silico prediction of transcript miRNA targets was performed using TargetScan and Miranda software's. FHCE1 immortalized epididymal cell lines were cotransfected with mimic microRNAs and plasmid constructs containing the 3'UTR of predicted target genes downstream of the luciferase gene.
  
  
  RESULTS
  We identified 35 miRNAs differentially expressed in the distinct segments of the epididymis (fold change ≥2, P-value ≤ 0.01). Among these miRNAs, miR-890, miR-892a, miR-892b, miR-891a, miR-891b belonging to the same epididymis-enriched cluster located on the X chromosome, are significantly more expressed in the corpus and cauda regions than in the caput. Interestingly, a strong negative correlation (r = -0,89, P-value ≤ 0.001) was found between the pattern of expression of miR-892b and its potential mRNA target Esrrg (Estrogen Related Receptor Gamma) and with miR-145 and Cldn10 mRNA (r = -0,92, P-value ≤ 0.001). We confirmed that miR-145 and miR-892b inhibit the expression of the luciferase reporter via Cldn10 and Esrrg 3' UTRs, respectively.
  
  
  CONCLUSIONS
  Our study shows that the expression of miRNAs is segmented along the human epididymis and correlates with the pattern of target gene expression in different regions. Therefore, epididymal miRNAs may be in control of the maintenance of gene expression profile in the epididymis, which dictates segment-specific secretion of proteins and establishes physiological compartments that directly or indirectly affect sperm maturation and fertility.
authors.affiliation: Centre de Recherche du CHUQ and Département d'Obstétrique-Gynécologie, Faculté de Médecine, Université Laval, Québec, Canada. clemence.belleannee@crchuq.ulaval.ca
authors.forename: Clémence
authors.initials: C
authors.lastname: Belleannée
authors.forename: Ezéquiel
authors.initials: E
authors.lastname: Calvo
authors.forename: Véronique
authors.initials: V
authors.lastname: Thimon
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Cyr
authors.forename: Christine
authors.initials: C
authors.lastname: Légaré
authors.forename: Louis
authors.initials: L
authors.lastname: Garneau
authors.forename: Robert
authors.initials: R
authors.lastname: Sullivan
mesh_terms: D002478:Cells, Cultured; D019295:Computational Biology; D004822:Epididymis / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: D035683:MicroRNAs