title: Toll-like receptor-4-mediated macrophage activation is differentially regulated by progesterone via the glucocorticoid and progesterone receptors.
abstract: Macrophage function has been demonstrated to be subject to modulation by progesterone. However, as this steroid hormone can act through the glucocorticoid receptor as well as the progesterone receptor, the mechanism of action has not been precisely characterized. To determine the mode of action, we compared the ability of progesterone, norgestrel (a synthetic progesterone-receptor-specific agonist) and dexamethasone (a synthetic glucocorticoid receptor agonist) to modulate macrophage function following stimulation of the Toll-like receptor-4 (TLR-4) ligand lipopolysaccharide (LPS). The results demonstrate that following stimulation of TLR-4 with LPS and cotreatment with either progesterone or dexamethasone, but not norgestrel, there is a significant reduction in nitric oxide (NO) production, indicating that this progesterone-mediated effect is through ligation of the glucocorticoid receptor. In contrast, LPS-induced interleukin-12 (IL-12) production could be downregulated by all three steroids, indicating that ligation by progesterone of either the glucocorticoid or the progesterone receptors or both could mediate this effect. While progesterone downmodulated NO-mediated killing of Leishmania donovani by activated macrophages in vitro, most probably via the glucocorticoid receptor, it had little effect on Toxoplasma gondii growth in these cells. This would suggest that progesterone-mediated increased susceptibility to T. gondii during pregnancy is more likely to be related to the ability of the hormone to downregulate IL-12 production and a type-1 response utilizing the progesterone as well as the glucocorticoid receptors.
authors: Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
authors: Leigh A
authors: LA
authors: Jones
authors: Jean-Paul
authors: JP
authors: Anthony
authors: Fiona L
authors: FL
authors: Henriquez
authors: Russell E
authors: RE
authors: Lyons
authors: Mohammad B
authors: MB
authors: Nickdel
authors: Katharine C
authors: KC
authors: Carter
authors: James
authors: J
authors: Alexander
authors: Craig W
authors: CW
authors: Roberts
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000276:immunology; D018664:Interleukin-12 / Q000096:biosynthesis; D007893:Leishmania donovani; D007898:Leishmaniasis, Visceral / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis; D009573:Nitrites / Q000378:metabolism; D009644:Norgestrel / Q000494:pharmacology; D011374:Progesterone / Q000276:immunology*; D011965:Receptors, Glucocorticoid / Q000276:immunology*; D011980:Receptors, Progesterone / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology
chemical_list: D008070:Lipopolysaccharides; D009573:Nitrites; D011965:Receptors, Glucocorticoid; D011980:Receptors, Progesterone; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D018664:Interleukin-12; D009569:Nitric Oxide; D009644:Norgestrel; D011374:Progesterone; D003907:Dexamethasone