ESA-SRB-AOTA 2019

The impact of acute acrylamide exposure on the small non-protein-coding RNA profile of mouse spermatozoa (#13)

Natalie A Trigg 1 , Shaun D Roman 1 2 , Andrew L Eamens 1 , Miguel J Xavier 1 , Brett Nixon 1
  1. Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
  2. Priority Research Centre for Drug Development, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308,, Australia

Mature spermatozoa harbour a diverse population of small non-protein-coding RNAs (sRNA), which are delivered to the oocyte upon fertilisation, and thereafter, influence embryonic development and the subsequent health of offspring. Moreover, the sperm sRNA profile has been demonstrated to be altered in response to a range of environmental insults, with significant post-fertilisation consequences. Here, we assessed the impact to the global sRNA profile of mouse sperm after exposure to the xenobiotic, acrylamide. In mice, acute acrylamide exposure is known to lead to paternal-mediated embryo loss owing to dysregulation of post-testicular sperm maturation in the epididymis, a critical developmental window during which the sperm sRNA profile is dramatically remodelled. Hence, we exposed adult male mice to acrylamide (25mg/kg bw/day; i.p.) for a 5-day period, timed to coincide with sperm epididymal transit. Following exposure, next-generation sequencing was employed to survey differences in the global sRNA profile of mature sperm. Our data revealed a subset of sRNAs that were significantly altered in spermatozoa following acrylamide exposure (i.e. sRNA species with either elevated or reduced abundance of ≥ 2-fold compared to controls; p<0.05). Alterations were documented for each major sRNA class, including the microRNA (miRNA) class. Specifically, 5.7% of all detected miRNAs were altered in their abundance. Furthermore, bioinformatic analysis identified the predominant pathways regulated by these differentially abundant miRNAs, including the cell growth and survival pathways implicated in early embryo development. Accordingly, we have validated the differential abundance of candidate miRNAs using RT-qPCR and confirmed that these changes originate in the sperm during epididymal transit. Building on these data, we now aim to elucidate the mechanisms by which acrylamide exposure mediates such pronounced changes in the sperm epigenetic landscape and determine the downstream biological consequences of an altered sperm miRNA profile on early embryo gene expression and development.