title: Involvement of GR and p300 in the induction of H6PD by cortisol in human amnion fibroblasts.
abstract: Human fetal membranes express 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which reduces biologically inert cortisone to active cortisol and may provide an extraadrenal source of cortisol mediating fetal development and parturition. The reductase activity of 11β-HSD1 depends on the availability of the cofactor reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) derived from the enzymatic activity of hexose-6-phosphodehydrogenase (H6PD). Based on the feed-forward induction of 11β-HSD1 by glucocorticoids in human fetal membranes, we hypothesize that glucocorticoids simultaneously induce H6PD in the fetal membranes. We found a parallel distribution of H6PD and 11β-HSD1 in the amnion, chorion, and decidua. In cultured human amnion fibroblasts, small interfering RNA-mediated knockdown of H6PD expression significantly attenuated the conversion of cortisone to cortisol. Cortisol (0.01-1 μm) induced H6PD expression in a concentration-dependent manner, which was attenuated by glucocorticoid receptor (GR) antagonist RU486. Cortisol induced the expression of p300, a histone acetyltransferase, whereas C646, an inhibitor of p300, attenuated the induction of H6PD by cortisol. Coimmunoprecipitation revealed GR and p300 in the same nuclear protein complex upon cortisol stimulation. Chromatin immunoprecipitation showed that cortisol increased the binding of p300 and GR to H6PD promoter and the acetylation of histone 3 lysine 9 on the promoters. In conclusion, the induction of H6PD by cortisol requires the participation of GR and p300 as well as the acetylation of H3K9 by p300. This may be a prerequisite for the parallel induction of reductase activity of 11β-HSD1 in human amnion fibroblasts in a feed-forward loop that may influence fetal development and the onset of parturition.
authors.affiliation: School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Wang
authors.forename: Chunming
authors.initials: C
authors.lastname: Guo
authors.forename: Wenjiao
authors.initials: W
authors.lastname: Li
authors.forename: Jianneng
authors.initials: J
authors.lastname: Li
authors.forename: Wangsheng
authors.initials: W
authors.lastname: Wang
authors.forename: Leslie
authors.initials: L
authors.lastname: Myatt
authors.forename: Kang
authors.initials: K
authors.lastname: Sun
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000378:metabolism; D000650:Amnion / Q000378:metabolism*; D002237:Carbohydrate Dehydrogenases / Q000096:biosynthesis*; D050881:E1A-Associated p300 Protein / Q000378:metabolism*; D005321:Extraembryonic Membranes / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D005938:Glucocorticoids / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism* / Q000494:pharmacology; D008239:Lysine / Q000737:chemistry; D015735:Mifepristone / Q000494:pharmacology; D009249:NADP / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism*
chemical_list: D005938:Glucocorticoids; D006657:Histones; D034741:RNA, Small Interfering; D011965:Receptors, Glucocorticoid; D015735:Mifepristone; D009249:NADP; D002237:Carbohydrate Dehydrogenases; C020552:galactose-6-phosphate dehydrogenase; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; D008239:Lysine; D006854:Hydrocortisone