The targeting and functions of miRNA-383 are mediated by FMRP during spermatogenesis

Cell Death Dis. 2013 May 2;4(5):e617. doi: 10.1038/cddis.2013.138.

Abstract

Our previous studies have shown that microRNA-383 (miR-383) expression is downregulated in the testes of infertile men with maturation arrest (MA). Abnormal testicular miR-383 expression may potentiate the connections between male infertility and testicular germ cell tumors. However, the mechanisms underlying the targeting and functions of miR-383 during spermatogenesis remain unknown. In this study, we found that fragile X mental retardation protein (FMRP) was associated with 88 miRNAs in mouse testis including miR-383. Knockdown of FMRP in NTERA-2 (NT2) (testicular embryonal carcinoma) cells enhanced miR-383-induced suppression of cell proliferation by decreasing the interaction between FMRP and miR-383, and then affecting miR-383 binding to the 3'-untranslated region of its target genes, including interferon regulatory factor-1 (IRF1) and Cyclin D1 both in vivo and in vitro. On the other hand, FMRP levels were also downregulated by overexpression of miR-383 in NT2 cells and GC1 (spermatogonia germ cell line). miR-383 targeted to Cyclin D1 directly, and then inhibited its downstream effectors, including phosphorylated pRb and E2F1, which ultimately resulted in decreased FMRP expression. Reduced miR-383 expression, dysregulated cyclin-dependent kinase 4 expression (one of the downstream genes of miR-383) and increased DNA damage were also observed in the testes of Fmr1 knockout mice and of MA patients with a downregulation of FMRP. A potential feedback loop between FMRP and miR-383 during spermatogenesis is proposed, and FMRP acts as a negative regulator of miR-383 functions. Our data also indicate that dysregulation of the FMRP-miR-383 pathway may partially contribute to human spermatogenic failure with MA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Base Sequence
  • Cell Line
  • Cell Proliferation
  • Cyclin D1 / genetics
  • Cyclin D1 / metabolism
  • Cyclin-Dependent Kinase 4 / metabolism
  • Down-Regulation
  • E2F1 Transcription Factor / metabolism
  • Fragile X Mental Retardation Protein / antagonists & inhibitors
  • Fragile X Mental Retardation Protein / genetics
  • Fragile X Mental Retardation Protein / metabolism*
  • Interferon Regulatory Factor-1 / genetics
  • Interferon Regulatory Factor-1 / metabolism
  • Male
  • Mice
  • Mice, Knockout
  • MicroRNAs / metabolism*
  • Phosphorylation
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Retinoblastoma Protein / metabolism
  • Spermatogenesis / genetics*
  • Testis / metabolism

Substances

  • 3' Untranslated Regions
  • E2F1 Transcription Factor
  • Interferon Regulatory Factor-1
  • MIRN383 microRNA, mouse
  • MicroRNAs
  • RNA, Small Interfering
  • Retinoblastoma Protein
  • Cyclin D1
  • Fragile X Mental Retardation Protein
  • Cyclin-Dependent Kinase 4