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p65-activated histone acetyltransferase activity is repressed by glucocorticoids: mifepristone fails to recruit HDAC2 to the p65-HAT complex.

Research paper by K K Ito, E E Jazrawi, B B Cosio, P J PJ Barnes, I M IM Adcock

Indexed on: 08 Jun '01Published on: 08 Jun '01Published in: Journal of Biological Chemistry



Abstract

Glucocorticoids acting through their specific receptor can either enhance or repress gene transcription. Dexamethasone represses interleukin-1beta-stimulated histone acetylation and granulocyte-macrophage colony-stimulating factor expression through a combination of direct inhibition of p65-associated histone acetyltransferase (HAT) activity and by recruiting histone deacetylase 2 (HDAC2) to the p65-HAT complex. Here we show that mifepristone, a glucocorticoid receptor partial agonist, has no ability to induce gene expression but represses interleukin-1beta-stimulated histone acetylation and granulocyte-macrophage colony-stimulating factor release by 50% maximally. Mifepristone was able to inhibit p65-associated HAT activity to the same extent as dexamethasone but failed to inhibit the natural promoter to an equal extent due to an inability to recruit HDAC2 to the p65-associated HAT complex. These data suggest that the maximal repressive actions of glucocorticoids require recruitment of HDAC2 to a p65-HAT complex. These data also suggest that pharmacological manipulation of specific histone acetylation status is a potentially useful approach for the treatment of inflammatory diseases.