Title: Silver nanoparticles disrupt germline stem cell maintenance in the Drosophila testis

Biography:

Dr. Baeg Gyeong Hun completed his Ph.D. in Biomedical Science at the Osaka University School of Medicine, Japan and his Postdoctoral studies at Harvard Medical School, Boston. He has also worked as an Assistant Professor in the Department of Pediatrics at New York Medical College, USA.  He is currently working as an Assistant professor in the Department of Anatomy at the National University of Singapore, Singapore. 

Abstract

Silver nanoparticles (AgNPs), one of the most popular nanomaterials, are commonly used in consumer products and biomedical devices, despite their potential toxicity. Recently, AgNP exposure was reported to be associated with male reproductive toxicity in mammalian models. However, there is still a limited understanding of the effects of AgNPs on reproduction, particularly on spermatogenesis. The fruit fly Drosophila testis can serve as an excellent in vivo model to elucidate the mechanisms underlying AgNP-induced defects in spermatogenesis, as germ lineages can be easily identified, traced and imaged. In this study, we evaluated AgNP-mediated toxicity on spermatogenesis by feeding Drosophila with AgNPs at various concentrations. We first observed a dose-dependent uptake of AgNPs in vivo. Concomitantly, AgNP exposure caused a significant decrease in the viability and delay in the development of Drosophila in a dose-dependent manner. Furthermore, AgNP-treated male flies showed a reduction in fecundity, and the resulting testes contained a decreased number of germline stem cells (GSCs) compared to controls. Interestingly, testes exposed to AgNPs exhibited a dramatic increase in the levels of reactive oxygen species and showed precocious GSC differentiation. Taken together, our study suggests that AgNP exposure may increase ROS levels in the Drosophila testis, leading to a reduction of GSC number by promoting premature GSC differentiation.