Cortisol Directly Stimulates Spermatogonial Differentiation, Meiosis, and Spermiogenesis in Zebrafish (Danio rerio) Testicular Explants

Author(s)

Tovo-Neto, Aldo ^{[1, 2, 3]} ; Martinez, Emanuel R. M. ^[1] ; Melo, Aline G. ^[1] ; Doretto, Lucas B. ^[1] ; Butzge, Arno J. ^[1] ; Rodrigues, Maira S. ^{[1, 3]} ; Nakajima, Rafael T. ^[1] ; Habibi, Hamid R. ^{[2, 4]} ; Nobrega, Rafael H. ^[1]

Affiliation

^[1] Sao Paulo State Univ, Inst Biosci, Dept Morphol, Reprod & Mol Biol Grp, Botucatu 18618970, SP - Brazil

^[2] Univ Calgary, Dept Biol Sci, Calgary, AB T2N 1N4 - Canada

^[3] Sao Paulo State Univ, Aquaculture Program CAUNESP, Jaboticabal 14884900, SP - Brazil

^[4] Univ Calgary, Dept Physiol & Pharmacol, Calgary, AB T2N 1N4 - Canada

• Document type: Journal article
• Source: BIOMOLECULES; v. 10, n. 3 MAR 2020.
• Web of Science Citations: 0

Abstract

Cortisol is the major endocrine factor mediating the inhibitory effects of stress on vertebrate reproduction. It is well known that cortisol affects reproduction by interacting with the hypothalamic-pituitary-gonads axis, leading to downstream inhibitory and stimulatory effects on gonads. However, the mechanisms are not fully understood. In this study, we provide novel data demonstrating the stimulatory effects of cortisol on spermatogenesis using an ex vivo organ culture system. The results revealed that cortisol treatment did not modulate basal androgen production, but it influenced transcript levels of a selected number of genes involved in the zebrafish testicular function ar (androgen receptor), star (steroidogenic acute regulatory), cyp17a1 (17 alpha-hydroxylase/17,20 lyase/17,20 desmolase), cyp11a2 (cytochrome P450, family 11, subfamily A, polypeptide 2), hsd11b2 (11-beta hydroxysteroid dehydrogenase), cyp2k22 (cytochrome P450, family 2, subfamily K, polypeptide 22), fkbp5 (FKBP prolyl isomerase 5), gr alpha (glucocorticoid receptor alpha), and gr beta (glucocorticoid receptor beta) in a short-term culture. We also showed that cortisol stimulates spermatogonial proliferation and differentiation in an androgen independent manner as well as promoting meiosis and spermiogenesis by increasing the number of spermatozoa in the testes. Moreover, we demonstrated that concomitant treatment with RU 486, a potent glucocorticoid receptor (Gr) antagonist, did not affect the cortisol effects on spermatogonial differentiation but blocked the induced effects on meiosis and spermiogenesis. Supporting the Gr-mediated effects, RU 486 nullified the cortisol-induced expression of sycp3l (synaptonemal complex protein 3), a marker for the meiotic prophase that encodes a component of the synaptonemal complex. This is consistent with in silico analysis that found 10 putative GREs (glucocorticoid response elements) upstream of the zebrafish sycp3l. Finally, we also showed that gr alpha mRNA is expressed in Sertoli and Leydig cells, but also in several types of germ cells, including spermatogonia and spermatocytes. Altogether, this evidence indicates that cortisol exerts paracrine roles in the zebrafish testicular function and spermatogenesis, highlighting its effects on spermatogonial differentiation, meiosis, and spermiogenesis. (AU)

• FAPESP's process: 14/07620-7 - Spermatogonial stem cell bank to preserve the genotype of endangered and valuable teleost species
• Grantee: Rafael Henrique Nóbrega
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 14/16280-5 - Molecular and endocrine control involved on gonadal differentiation of zebrafish (Danio rerio)
• Grantee: Aldo Tovo Neto
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/22778-3 - Spermatogonial stem cell bank to preserve the genotype of endangered and valuable teleost species
• Grantee: Emanuel Ricardo Monteiro Martinez
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/15793-7 - Effects of hypothyroidism on testicular function of Danio rerio and relation between thyroid hormones and follicle stimulating hormone (Fsh)
• Grantee: Maira da Silva Rodrigues
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/12101-4 - Selection, Culture and Transcriptome of spermatogonial stem cells of zebrafish, Danio rerio: a functional and genomics approach
• Grantee: Lucas Benites Doretto
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 15/12104-0 - Effects of cortisol in zebrafish spermatogenesis as mean to understand the role of this steroid during thermal stress induced sex differentiation
• Grantee: Aline Gomes Melo
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 17/09218-0 - Effects of methimazole-induced thyroid hormone insufficiency on zebrafish (Danio rerio) spermatogenesis
• Grantee: Aldo Tovo Neto
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate