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Interaction between thyroid hormones and circadian clock genes: consequences on anterior pituitary hormones secretion

Grant number: 16/24941-7
Support type:Scholarships abroad - Research Internship - Post-doctor
Effective date (Start): April 01, 2017
Effective date (End): March 31, 2018
Field of knowledge:Biological Sciences - Physiology - General Physiology
Principal researcher:Maria Tereza Nunes
Grantee:Paula Bargi de Souza
Supervisor abroad: Patrice Eric Jean-Jacques Mollard
Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Research place: Institut de Génomique Fonctionnelle (IGF), France  
Associated to the scholarship:14/25888-7 - Characterization of the molecular basis involved on the expression of circadian clock genes in the pituitary at different thyroid states and the consequences for the synthesis/secretion of anterior pituitary hormones, BP.PD

Abstract

The anterior pituitary gland occupies a central position in the hypothalamus-pituitary-gland/tissues axes, regulating the synthesis/secretion of hormones related to reproduction, growth and metabolism. The plasma concentration of pituitary hormones fluctuates over 24 h. The generation/maintenance of circadian rhythmicity, central or peripheral, is determined by a set of genes called clock genes involved in an auto-regulatory transcriptional-(post)translational-based feedback loop within a 24 h period and in the regulation of several genes related to rhythmicity, hormonal response, growth regulation and cell death in anterior pituitary cells. It is known that GH, TSHB and LH secretions are altered in hypo and hyperthyroidism and that the triiodothyronine (T3) availability in peripheral tissues is controlled by the activity of Deiodinase 2, which in turn, presents a circadian rhythm. All these data suggest that the anterior pituitary cells present an intrinsic circadian clock and that clock genes expression might be altered in different thyroidal states, direct or indirectly, altering the synthesis/secretion pattern of anterior pituitary hormones. To investigate this hypothesis, an evaluation of the synthesis/secretion of pituitary hormones and the expression of clock genes will be performed in two models: a) the double knockout mice for Cry1 and 2 (global disrupted clock) and b) the specific Tshb-cre mice crossed with floxed Bmal1 (cell-specific clock disruption). Both models will be subjected to hypo and hyperthyroidism in adult age. In these conditions, the clock genes mRNA content in pituitary will be assayed by RT-qPCR, the circadian secretion of pituitary hormones (every 3h for 24h) will be evaluated using ELISA assay, the distribution of BMAL1 in pituitary cell types by immunohistochemistry and the locomotor-activity rhythm by running wheel performance analysis. Thus, the goal of this project is to correlate the alterations observed in the different hypothalamic-pituitary-gland axes during the hypo- and hyperthyroidism with the major role of the circadian clock within pituitary gland. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FIGUEIRA DA COSTA, TATIENNE NEDER; ANDREOTTI, SANDRA; DE FARIAS, TALITA DA SILVA MENDES; LIMA, FABIO BESSA; BARGI-SOUZA, PAULA. The Influence of Melatonin on the Daily 24-h Rhythm of Putative Reference Gene Expression in White Adipose Tissues. JOURNAL OF BIOLOGICAL RHYTHMS, v. 35, n. 6 SEP 2020. Web of Science Citations: 0.
KEMKEM, YASMINE; NASTESKA, DANIELA; DE BRAY, ANNE; BARGI-SOUZA, PAULA; PELICIARI-GARCIA, RODRIGO A.; GUILLOU, ANNE; MOLLARD, PATRICE; HODSON, DAVID J.; SCHAEFFER, MARIE. Maternal hypothyroidism in mice influences glucose metabolism in adult offspring. Diabetologia, v. 63, n. 9, p. 1822-1835, SEP 2020. Web of Science Citations: 1.

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