Testicular Dysgenesis Syndrome and Long-Lasting Epigenetic Silencing of Mouse Sperm Genes Involved in the Reproductive System after Prenatal Exposure to DEHP

PLoS One. 2017 Jan 13;12(1):e0170441. doi: 10.1371/journal.pone.0170441. eCollection 2017.

Abstract

The endocrine disruptor bis(2-ethylhexyl) phthalate (DEHP) has been shown to exert adverse effects on the male animal reproductive system. However, its mode of action is unclear and a systematic analysis of its molecular targets is needed. In the present study, we investigated the effects of prenatal exposure to 300 mg/kg/day DEHP during a critical period for gonads differentiation to testes on male mice offspring reproductive parameters, including the genome-wide RNA expression and associated promoter methylation status in the sperm of the first filial generation. It was observed that adult male offspring displayed symptoms similar to the human testicular dysgenesis syndrome. A combination of sperm transcriptome and methylome data analysis allowed to detect a long-lasting DEHP-induced and robust promoter methylation-associated silencing of almost the entire cluster of the seminal vesicle secretory proteins and antigen genes, which are known to play a fundamental role in sperm physiology. It also resulted in the detection of a DEHP-induced promoter demethylation associated with an up-regulation of three genes apparently not relevant for sperm physiology and partially related to the immune system. As previously reported, DEHP induced an increase in mir-615 microRNA expression and a genome-wide decrease in microRNA promoter methylation. A functional analysis revealed DEHP-induced enrichments in down-regulated gene transcripts coding for peroxisome proliferator-activated receptors and tumor necrosis factor signaling pathways, and in up-regulated gene transcripts coding for calcium binding and numerous myosin proteins. All these enriched pathways and networks have been described to be associated in some way with the reproductive system. This study identifies a large new array of genes dysregulated by DEHP that may play a role in the complex system controlling the development of the male reproductive system.

MeSH terms

  • Animals
  • DNA Methylation / drug effects
  • Diethylhexyl Phthalate / toxicity*
  • Endocrine Disruptors / toxicity*
  • Epigenesis, Genetic / drug effects
  • Female
  • Fetal Development / drug effects
  • Gene Expression Regulation, Developmental / drug effects*
  • Gene Silencing / drug effects
  • Male
  • Mice
  • MicroRNAs / metabolism
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Promoter Regions, Genetic
  • Reproduction / genetics*
  • Syndrome
  • Testicular Diseases / chemically induced*
  • Testicular Diseases / genetics
  • Testis / drug effects
  • Testis / embryology
  • Transcriptome

Substances

  • Endocrine Disruptors
  • MicroRNAs
  • Diethylhexyl Phthalate

Grants and funding

The grant of this project initially called "Impact of prenatal exposure to di-(2-ethylhexyl)phthalate on epigenetically dysregulated RNA in mice sperm associated with fertility decrease" was successfully granted the 7th September 2015 by the Swiss Center for Applied Human Toxicology (SCAHT, http://www.scaht.org/).