Lightning Talk + Poster ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Leveraging spermatogonial stem cells for koala conservation (#409)

Katerina B Damyanova 1 2 3 , Tessa Lord 1 2 3 , Brett Nixon 1 2 3 , Stephen D Johnston 4 5 , Andres Gambini 5 6 , Patricio P Benitez 6
  1. The University of Newcastle, Callaghan, NSW, Australia
  2. Reproductive Biology, Infertility and Reproduction Research Program, Hunter Medical Research Institute, Newcastle, NSW, Australia
  3. Hunter Medical Research Institute, Infertility and Reproduction Research Program, Newcastle, New South Wales, Australia
  4. School of Environment, The University of Queensland, Gatton, Queensland, Australia
  5. School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
  6. School of Agriculture and Food Science, The University of Queensland, Gatton, Queensland, Australia

The iconic koala, one of Australia's most beloved native species, is facing an unprecedented threat to its survival due to devastating bushfires, drought, habitat loss, and diseases. These challenges have led to its reclassification as an endangered species in QLD, NSW and ACT by the Australian government. Spermatogenesis, the foundation of male germline continuity, relies on spermatogonial stem cells (SSCs). While SSCs have proven valuable in human fertility research, their potential role in conserving endangered wildlife, particularly koalas, remains largely unexplored.

Successful conservation strategies depend on the maintenance and expansion of SSCs in culture while preserving their integrity to re-establish spermatogenesis. The current lack of fundamental knowledge about these cells, especially in wildlife species, is a primary limitation to developing SSC biobanking strategies. To bridge this knowledge gap, we optimized the isolation of seminiferous tubules for whole-mount analysis using one-step enzymatic digestion with DNase and collagenase and identified molecular markers specific to undifferentiated spermatogonia in koalas.

This study is crucial for enabling the isolation and in vitro expansion of koala SSCs. Using immunohistochemistry in whole-mount seminiferous tubules and paraffin-embedded testicular tissue, we identified the presence of key spermatogonial (UCHL1, DDX4, TEX14), support cell (SOX9, GATA4) and proliferative (PCNA) markers in the koala testis. Additionally, we discovered the conserved presence of hypoxic (EPAS1) pathways previously established in the mouse model, which could inform culture conditions for in vitro maintenance and expansion of koala SSCs.

Delineating species-specific spermatogonial markers will enhance the isolation and enrichment of koala SSCs, increasing the efficiency of downstream applications such as spermatogonial transplantation, testis tissue grafting, and in vitro spermatogenesis coupled with assisted reproductive techniques. These advancements are pivotal in bolstering koala conservation efforts.