SAT278 Thyroid Hormones Regulate 11bhsd Enzymes: A Novel Function In Glucocorticoid Hormone Metabolism

Abstract

Abstract Disclosure: L. Bessiene: None. J. Perrot: None. S. Hescot: None. A. Bourdin-Pintueles: None. G. Vitellius: None. L.M. Sachs: None. P. Kamenicky: None. M. Lombes: None. E. Pussard: None. S. Viengchareun: None. L. Martinerie: None. Glucocorticoid hormone metabolism is regulated by 11-beta hydroxysteroid dehydrogenase enzymes: 11βHSD2, mostly expressed in the distal nephron, converts corticosterone into 11-dehydrocorticosterone in rodents, while 11βHSD1 catalyzes the opposite reaction in liver. Glucocorticoid hormone metabolism may be altered under pathophysiological conditions of hypothyroidism. However, direct functional relationship between glucocorticoid and thyroid hormones (T3) signaling pathways remains elusive. Identification of putative Thyroid Response Elements (TRE) in the promoter regions of hsd11b2 and hsd11b1 genes suggested that T3 might directly regulate expression and/or activity of these enzymes.We used human translational studies, a mouse model of hyperthyroidism and murine renal and hepatic cell lines to investigate the role of thyroid hormones in glucocorticoid hormone metabolism.In hypothyroid patients, the urinary [E]/[F] ratio measured by LC-MS/MS technology, showed a 60% decrease (P<0.05), compared to age- and sex- matched euthyroid controls, suggesting a regulation of glucocorticoid metabolism by T3. Similarly, a significant positive correlation was observed between the urinary [E]/[F] ratio and serum T4L concentration in hyperthyroid patients before and after normalization of T4L levels.Administration of T3 in drinking water, mimicking a mouse model of hyperthyroidism, led to significant increase in renal 11βHSD2 mRNA (P<0.05) and decrease in liver 11βHSD1 mRNA and protein levels (P<0.01), compared to control mice.Finally, T3 induced an increase in 11βHSD2 transcript levels in renal KC3AC1 cells (P<0.01) and a decrease in 11βHSD1 mRNA levels in hepatic HepG2 cells (P<0.01). 11βHSD2 activity increased by 20% (P<0.05). In HEK 293T cells, T3 transactivated hsd11b2 promoter via the Thyroid Receptor α1 (TRα1). ChIP experiments further demonstrated a T3-dependent specific recruitment of TRα1 onto hsd11b2 promoter. Altogether, these findings demonstrate that T3 directly regulate expression and activity of 11βHSD enzymes, thereby controlling glucocorticoid hormone metabolism and action. Presentation: Saturday, June 17, 2023