The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2018

The impact of environmental insult on the small RNA profile of spermatozoa (#313)

Natalie A Trigg 1 , Andrew L Eamens 2 , Geoffry N De Iuliis 1 , Elizabeth G Bromfield 1 , Brett Nixon 1
  1. Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
  2. Centre for Plant Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia

Inheritance of epigenetic information, which occurs independent of an individual’s DNA sequence, is now a well-accepted paradigm. Among the potential mechanisms for relaying epigenetic information between generations, considerable attention has been focused on small non-protein-coding RNA (sRNA). Indeed, there is growing recognition that the profile of sperm sRNA is altered in response to diverse environmental insults with significant post-fertilisation consequences, including altered behavioural and metabolic phenotypes in the offspring. While these data firmly implicate the male gamete as an important vehicle for epigenetic inheritance, the precise timing and mechanism(s) responsible for effecting changes in the sperm sRNA profile have yet to be established. To begin to address these questions, we have employed next generation sequencing strategies to determine the impact of three physiologically relevant environmental stressors; (i) elevated ambient temperature, (ii) radiofrequency electromagnetic energy (RF-EME) and (iii) acute acrylamide exposure on the sRNA profile of mature sperm. Our data has revealed a subset of sRNAs that are significantly altered (i.e. experience an increased or decreased accumulation) in the spermatozoa of male mice exposed to these environmental insults. Interestingly, exposure to RF-EME led predominantly to decreased accumulation of a subset of micro RNAs (miRNAs), while conversely exposure to acrylamide and elevated ambient temperature primarily resulted in an increased accumulation of miRNAs. Our data also demonstrated conservation in miRNA alterations in response to stress, with seven miRNAs differentially expressed in more than one of the insults investigated. We now aim to determine the mechanism(s) by which these sperm sRNA candidates are altered, with a particular focus on the role of epididymal extracellular vesicles, as well as the impact these sRNA changes have on embryo development and offspring health.