Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Investigating a role for sirtuin 1 in governing spermatogonial stem cell function      (#427)

Jess M Lyons 1 , Elizabeth G Bromfield 2 , Shannon P Smyth 2 , Tessa Lord 1
  1. Discipline of Biological Sciences, College of Engineering, Science and Environment, The University of Newcastle, Newcastle, NSW, Australia
  2. School of Biosciences, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia

Spermatogonial stem cells (SSCs) are the basis for male fertility, and their destruction and/or depletion damages reproductive potential. Targeted manipulation of SSCs provides an exciting avenue for the restoration of fertility following oncological treatment. However, development of these technologies requires in-depth understanding of the molecular regulators involved in the interplay between self-renewal and differentiation commitments. In this project, we seek to identify the involvement of sirtuin 1 (SIRT1), a NAD+-dependent deacetylase with apparent male reproductive functions, in contributing to SSC maintenance and response to chemotherapy treatment.

In mining a previously published single-cell RNA sequencing dataset1, we have identified expression of sirtuin 1 throughout the undifferentiated spermatogonia population. Encouragingly, a recent phosphoproteomic analysis of SSC and progenitor spermatogonia conducted by our research group identified SIRT1 signalling as a canonical pathway modulating SSC activity. Further, an RNAseq comparison of undifferentiated spermatogonia pre- and post- chemotherapy treatment2 predicted SIRT1 as an upstream regulator of the regenerative response (Ingenuity Pathway Analysis). To further explore the role of SIRT1 in SSCs, we have developed a mouse line combining global overexpression of SIRT1 (SIRT1-OE) with an Id4-eGfp reporter transgene that labels SSCs and progenitor spermatogonia. SIRT1 overexpression has been confirmed using PCR, immunoblotting and immunofluorescence approaches. Using this model, we will next ascertain whether SIRT1 exerts effects on spermatogonial function, including regeneration following exposure to the chemotherapeutic busulfan. In preliminary experiments using control animals, we have identified that spermatogonia with the highest expression of ID4-eGFP transgene are likely responsible for repopulation of the germline following chemotherapy by initiating rapid cell cycling. We will explore whether SIRT1-OE can improve this response to achieve more rapid recovery of fertility. This research will provide insight into the key molecular pathways that may be targeted for the development of SSC technologies and therapies to restore fertility following cancer treatments.

  1. 1 Hermann, B. P. et al. The Mammalian Spermatogenesis Single-Cell Transcriptome, from Spermatogonial Stem Cells to Spermatids. Cell Reports 25, 1650-1667.e1658, doi:https://doi.org/10.1016/j.celrep.2018.10.026 (2018).
  2. 2 La, H. M. et al. Distinctive molecular features of regenerative stem cells in the damaged male germline. Nature Communications 13, 2500, doi:10.1038/s41467-022-30130-z (2022).