Development of testicular organoids and their use for potential sperm maturation in Zebrafish (Danio rerio) and Tambaqui (Colossoma macropomum)

Abstract

Testicular organoids are three-dimensional clusters derived from testicular cells (spermatogonial stem cells) that exhibit in vitro the same cytoarchitecture and functionality of testis in vivo. Due to the characteristics, this technology has been providing great possibilities for studies in the fundamental area as alternatives to animal experimentation and classic cell line models. To our knowledge, there are no testicular organoids developed for fish until now. Thus, this technology could be used to produce sperm in vitro for species that have a long period of sexual maturation, such as Tambaqui (Colossoma macropomum). This research proposal, in a first moment, aims to generate 3D testicular organoids using a model fish (Danio rerio) and a native species Tambaqui (Colossoma macropomum). Subsequently, to evaluate the efficiency of the employed method, testicular organoids will be characterized by morphological and functional assays. In a second step, the transcriptomic profile of maturing testicles and Tambaqui neo-males will be analyzed via (RNAseq), identifying candidates involved in maturation of this species. Finally, pre-selected candidates will be functionally tested via testicular organoids in Tambaqui in order to accelerate the process of maturation and formation of gametes. In summary, this research proposal, to be developed, will allow the development of modern technologies for the study of fish spermatogenesis/spermatogonial stem cells, from functional, and zootechnical aspects. This research is part of two submitted research grants (Auxílio Regular à Pesquisa - 2020/03569-8; Auxílio Regular à Pesquisa - FAPEAM-FAPESP 2020/08627-6). (AU)