Interleukin-34 is a Novel Testicular Factor that Induced Proliferation, Meiotic and Postmeiotic Stages of Mouse Spermatogonial Cells in Vitro - Israeli Fertility Association Conference-Ayala 2018, May 7-8, Dan Panorama Hotel, Tel-Aviv

Alaa Sawaied ¹ Eitan Lunenfeld ² Mahmoud Huleihel ³

¹The Shraga Segal Dep. of Microbiology, Immunology and Genetics, The Center of Advanced Research and Education in Reproduction (CARER), Faculty of Health Sciences, Ben-Gurion University of the Negev
²Dep. OB/GYN, Soroka Medical Center, The Center of Advanced Research and Education in Reproduction (CARER), Faculty of Health Sciences, Ben-Gurion University of the Negev
³The Shraga Segal Dep. of Microbiology, Immunology and Genetics, The Center of Advanced Research and Education in Reproduction (CARER), Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev

Introduction: Interlukin-34 is a protein produced mainly by neurons and keratocyties. It binds and act through colony stimulating factor-1 receptor (CSF-1R). This receptor was also found on spermatogonial stem cells. We already demonstrated the expression of IL-34 in testicular tissue and cells such as Sertoli, Leydig and peritubular cells. The role of IL-34 in spermatogenesis was not yet identified.

Aim: To evaluate the effect of IL-34 in proliferation and differentiation of mouse spermatogonial cells in vitro.

Material & Methods: Seven-day-old mice were used. Cells from seminiferous tubules were enzymatically isolated. These cells were cultured in methylcellulose (as 3three-dimension culture system) in the presence of FBS, different growth factors and with/without IL-34 (0.01-10 ng/ml). Developed cells were collected after 4 weeks of culture, and examined for premeiotic, meiotic and postmeiotic stages by immunofluorescence staining using antibodies specific to each stage.

Results: Our results show development of spermatogenic cells of all stages after 4 weeks in methylcellulose in vitro culture. Addition of recombinant IL-34 was significantly increased the proliferation of premeiotic cells (VASA) and the development of meiotic (BOULE) and postmeiotic (ACROSIN) compared to control cultures (without IL-34) after 4 weeks in methylcellulose in vitro culture. This effect was in dose-dependent manner when the optimal effect was in 0.01 and 0.1 ng/ml.

Conclusion: Our results show for the first time that IL-34 is involved in the proliferation and differentiation of mouse spermatogonial stem cells to meiotic and postmeiotic stages under in vitro conditions. These results may suggest its role in the physiology of spermatogenesis in vivo.