Identification of germ cell-intrinsic players (gdnf and long non-coding rnas) involved in the spermatogonial stem cell fate of adult zebrafish

Lucas Benites Doretto

Full text
Author(s):	Lucas Benites Doretto Total Authors: 1
Document type:	Doctoral Thesis
Press:	Botucatu. 2023-08-15.
Institution:	Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu
Defense date:	2023-06-23
Advisor:	Rafael Henrique Nóbrega
Abstract
Spermatogenesis is a process controlled by stem cells in which a single spermatogonial 46 stem cell (SSC) differentiates into many haploid spermatozoa. The division of SSC follows either 47 the asymmetric model, where one stem cell produces a differentiated cell and a stem cell (self-48 renewal), or the symmetric model, where one stem cell produces two differentiated cells or two 49 stem cells. Regardless of the model, the process of self-renewal and differentiation is regulated by 50 numerous signals from the surrounding somatic tissue (the stem cell niche) and the germline stem 51 cells themselves. Additionally, recent studies have shown that non-coding RNAs (microRNAs, 52 circRNAs, lncRNAs) from the germline niche itself can play a crucial role in reproduction, 53 particularly in the regulation of sexual determination, sexual differentiation, and gametogenesis. 54 Among the non-coding RNAs, lncRNAs stand out for their regulatory role in the transcription of 55 "master genes" involved in various biological processes, including the differentiation and 56 maintenance of stem cell pluripotency. In this context, this study aimed to understand the Gdnf-57 Gfrα1 signaling in zebrafish testes by combining in vivo, in silico, and ex vivo approaches, as well 58 as the biological effects of Fsh on testicular lncRNAs. Our data revealed that Gdnf, now a germ 59 cell-derived factor, is involved in maintaining germline stem cell pluripotency through niche 60 creation, supporting the development of spermatogonial cysts and inhibiting late spermatogonial 61 differentiation in an autocrine and paracrine manner. Furthermore, in this study, we identified 5161 62 novel lncRNAs and 76 DEGs under the influence of rzfFsh, of which 46 were upregulated and 30 63 were downregulated. Additionally, enrichment analyses of the DEGs demonstrated that these 64 transcripts are broadly related to signaling and organ systems, such as the endocrine system. When 65 focusing on mRNAs, we found 270 DEGs, with 174 upregulated and 96 downregulated. 66 Interestingly, the most enriched pathways were related to thyroid hormone signaling and 67 steroidogenesis. Finally, predictions of interaction between lncRNAs-mRNAs-proteins showed 68 that some lncRNAs can interact, and consequently, modulate the expression of pluripotency genes 69 in SSCs, such as pou5f3, nanos3, and nanog. Collectively, our data indicate a likely activity of Fsh 70 in creating a more favorable environment for spermatogonial stem cell differentiation. (AU)

FAPESP's process:	19/05643-3 - Identification of lncRNAs in germinative and somatic cells in testis of Zebrafish (Danio rerio) and its use as potential biomarkers of enviromental contamination
Grantee:	Lucas Benites Doretto
Support Opportunities:	Scholarships in Brazil - Doctorate

Short URL