title: Distinctive changes in histone H3K4 modification mediated via Kdm5a expression in spermatogonial stem cells of cryptorchid testes.
abstract: OBJECTIVE
  Gonocytes differentiate into spermatogonial stem cells, which make it possible to maintain spermatogenesis continuously throughout life. We previously reported attenuated spermatogonial stem cell activity in cryptorchid testes, which resulted in altered spermatogenesis and affected fertility. However, few groups have examined the differentiation process from gonocytes to spermatogonial stem cells. To clarify the underlying mechanisms comprehensively we performed microarray analysis to assess differential expression of transcripts between normal and undescended testes in juvenile rats.
  
  
  METHODS
  Using microarray analysis we compared whole mRNA expression of normal and cryptorchid testes in a rat model. We subsequently validated differential expression of candidate genes by real-time reverse transcriptase-polymerase chain reaction and performed immunohistochemistry. We also investigated the methylation status of histone H3K4 in cryptorchid testes and the GC-1 spermatogonial cell line.
  
  
  RESULTS
  We detected 24 up-regulated and 39 down-regulated genes. Of these genes Kdm5a expression was significantly higher in undescended testes. Immunohistochemistry showed that Kdm5a was localized in the nuclei of gonocytes, spermatogonia and spermatocytes. H3K4me2/me3 expression levels were decreased in undescended testes at 9 days postpartum. Furthermore, Kdm5a over expression in GC-1 cells led to increased expression of Esr2, Neurog3, Pou5f1, Ret and Thy1.
  
  
  CONCLUSIONS
  Recent investigations revealed that not only genetic but also epigenetic regulation has a role in spermatogenesis. Kdm5a is likely involved in the transformation of gonocytes into spermatogonial stem cells by transcriptional regulation of specific genes via H3K4 histone modification. To our knowledge this is the first report of epigenetic analysis of germ cell differentiation during early spermatogenesis.
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Nishio
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan. Electronic address: yutaro@med.nagoya-cu.ac.jp.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Moritoki
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kamisawa
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Mizuno
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kojima
authors.affiliation: Department of Nephro-Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya and Department of Urology, Fukushima Medical University School of Medicine (YK), Fukushima, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kohri
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D003456:Cryptorchidism; D044127:Epigenesis, Genetic / Q000502:physiology*; D006657:Histones; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D056485:Retinoblastoma-Binding Protein 2; D013091:Spermatogenesis / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology; D013737:Testis / Q000166:cytology* / Q000502:physiology; D046888:Tissue Array Analysis; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000502:physiology
chemical_list: D006657:Histones; D056485:Retinoblastoma-Binding Protein 2
keywords: cryptorchidism; epigenesis; genetic; histones; spermatogenesis; testis