Crossover between stress and thyroid hormone axes in stress-induced sex reversal.

CASTAÑEDA CORTÉS, D.C.; BOAN, A.; ZHANG, Y.; LANGLOIS, V.S.; FERNANDINO, J.I.

Congreso; X Latin American Society for Developmental Biology Meeting.; 2019

Latin American Society for Developmental Biology

In many fish species, environmental stressors, like high temperatures (HT), induces sex reversal of genotypic females (GF) to phenotypic male. In a previous study, we elucidate that all begins in the brain with the early increase of crhb and the concomitant whole body cortisol level raise in respond to environmental stress. However, the mechanism of how the brain regulates the gonadal sex determination directing the testis development has not been fully elucidated. Recent studies showed that exposure to thyroid hormones (THs) can induce sex reversion in fish. Besides, in non-mammalian species CRH can induce the thyroid-stimulating hormone (TSH) secretion in the pituitary of adults through the CRH type 2 receptor (CRHR2) in thyrotrope cells, linking the stress and thyroid endocrine axes. Firstly we performed a microarray after exposure embryos to HT, showing a whole effects of stress , e.i. crhb, gr2, and the up-regulation of thyroid axes, e.i. tsh, tg, and iyd. To corroborate the participation of TSH in the stress-induced sex reversal we performed biallelic mutant embryos for both crhrs by CRISPR/Cas9 exposed to HT, observing a down-regulation of tsh that phenocopied the control group. Finally, we corroborate that both axes contribute to the synthesis of androgens, the final inductor of testis development. In this study, we provide clear evidence of the crosstalk between stress and THs axes in the stress-induced female-to-male sex reversal.