Oral Presentation Australasia Extracellular Vesicles Conference 2017

Extracellular vesicles – the next small thing in epigenetic inheritance (#24)

Navind Jayasooriah 1 2 , Paul E Young 1 , Sally A Eaton 1 3 , Jennifer E Cropley 1 3 , Catheirne M Suter 1 3
  1. Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
  2. Faculty of Science, University of New South Wales, Sydney, NSW, Australia
  3. Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia

Epigenetics is the study of mitotically heritable changes in gene expression that are not caused by changes in DNA sequence. Environment effects such as diet and stress are able to affect an individual’s epigenotype and phenotype. These effects can persist beyond the initial exposed generation, suggesting that a signal is passed through the germline. However it is not known what the signal is, or its mechanism of transmission. We propose that the signal is somatic-derived non-coding RNA that is packaged inside extracellular vesicles (EVs)1. We have started to test this hypothesis in vitro using Sertoli cells, a germline‑associated somatic cell. We aimed to determine if Sertoli EVs interact with germ cells, and investigate whether environment stress alters Sertoli EV small RNA cargo.

We exposed Sertoli cells to dimethyl sulfoxide (DMSO) and bisphenol A (BPA), a known reproductive toxin, for 12 days. EVs were isolated by differential centrifugation and filtration, and analysed by transmission electron microscopy, nanoparticle tracking analysis and protein mass spectrometry. EVs were labelled with fluorescent cytosolic and membrane dyes, cocultured with spermatogonial stem cells, and then visualised by confocal microscopy. RNA was extracted from cells and EVs, small RNA libraries were constructed, and then sequenced on the Illumina platform. Differential expression analysis was performed in R using the edgeR package.

Here we show that Sertoli EVs are able to bind and fuse with spermatogonial stem cells in vitro. Exposure to both BPA and DMSO changed the number of EVs released per Sertoli cell. Additionally, exposure altered the selective packaging of small RNA inside the EVs, with differentially expressed microRNAs implicated in defective germ cell renewal and maintenance. Taken together, this suggests that EVs may be transmitting information about the environment from the soma to the germline – that EVs are a vector for epigenetic inheritance.

  1. Eaton, S. A., Jayasooriah, N., Buckland, M. E., Martin, D. I., Cropley, J. E., & Suter, C. M. (2015). Roll over Weismann: extracellular vesicles in the transgenerational transmission of environmental effects. Epigenomics, 7(7): 1165-1171.