The hypoxia-inducible factor EPAS1 is required for spermatogonial stem cell function in regenerative conditions

Ilana R Bernstein; Brett Nixon; Jess M Lyons; Katerina B Damyanova; Camila S De Oliveira; Nishani S Mabotuwana; Simone J Stanger; Gerard E Kaiko; Tan Hui Ying; Jon M Oatley; Nicole M Skillen; Alyssa J Lochrin; Jera L Peters; Tessa Lord

doi:10.1016/j.isci.2023.108424

The hypoxia-inducible factor EPAS1 is required for spermatogonial stem cell function in regenerative conditions

iScience. 2023 Nov 9;26(12):108424. doi: 10.1016/j.isci.2023.108424. eCollection 2023 Dec 15.

Authors

Ilana R Bernstein¹, Brett Nixon^{1

2}, Jess M Lyons¹, Katerina B Damyanova¹, Camila S De Oliveira¹, Nishani S Mabotuwana¹, Simone J Stanger¹, Gerard E Kaiko^{3

4}, Tan Hui Ying^{3

4}, Jon M Oatley⁵, Nicole M Skillen¹, Alyssa J Lochrin¹, Jera L Peters¹, Tessa Lord^{1

2}

Affiliations

¹ Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
² Hunter Medical Research Institute, Infertility and Reproduction Program, New Lambton Heights, NSW 2305, Australia.
³ Hunter Medical Research Institute, Immune Health Research Program, New Lambton Heights, NSW 2305, Australia.
⁴ School of Biomedical Sciences and Pharmacy, College of Health and Medicine, The University of Newcastle, Callaghan, NSW 2308, Australia.
⁵ School of Molecular Biosciences, Centre for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA.

Abstract

In this study we explored the role of hypoxia and the hypoxia-inducible transcription factor EPAS1 in regulating spermatogonial stem cell (SSC) function in the mouse testis. We have demonstrated that SSCs reside in hypoxic microenvironments in the testis through utilization of the oxygen-sensing probe pimonidazole, and by confirming the stable presence of EPAS1, which is degraded at >5% O₂. Through the generation of a germline-specific Epas1 knockout mouse line, and through modulation of EPAS1 levels in primary cultures of spermatogonia with the small drug molecule Daprodustat, we have demonstrated that EPAS1 is required for robust SSC function in regenerative conditions (post-transplantation and post-chemotherapy), via the regulation of key cellular processes such as metabolism. These findings shed light on the relationship between hypoxia and male fertility and will potentially facilitate optimization of in vitro culture conditions for infertility treatment pipelines using SSCs, such as those directed at pediatric cancer survivors.

Keywords: Biological sciences; Cell biology; Physiology.