Publications by authors named "P A McNiff"

A significant improvement in agonist activity of the previously described 2-aryloctahydrophenanthrene-2,3,7-triol series of dissociated glucocorticoid receptor agonists (DAGRs) was achieved by modifying the substitution at C3 from (S)-3-hydroxy to (R)-3-hydroxy-3-methyl. The IC50 of the prototype 13 in the efficacy assay measuring repression of IL-1 induced MMP-13 expression was 3.5 nM, exhibiting 87% of the maximal effect of dexamethasone (DEX).

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As exemplified by the lead compound 2, octahydrophenanthrene-2,7-diol analogues exhibit the profile of a pathway-selective or "dissociated" agonist of the glucocorticoid receptor (GR), retaining the potent activity that glucocorticoids have for transrepression (as measured by inhibition of IL-1 induced MMP-13 expression) but showing an attenuated capacity for transactivation (as measured in an MMTV luciferase reporter assay). With the guidance of a homology model of the GR ligand binding domain, structural modifications to 2 were carried out that were successful in replacing the allyl and propynyl side chains with groups likely to be more chemically stable and less likely to produce toxic metabolites. Key to success was the introduction of an additional hydroxyl group onto the tricyclic carbon framework of the series.

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Lipopolysaccharide (LPS)-activated monocytes and macrophages produce large quantities of pro-interleukin (IL)-1beta but externalize little mature cytokine. Efficient post-translational processing of the procytokine occurs in vitro when these cells encounter a secretion stimulus such as ATP, cytolytic T cells, or hypotonic stress. Each of these stimuli promotes rapid conversion of 31-kDa pro-IL-1beta to its mature 17-kDa species and release of the 17-kDa cytokine.

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LL-Z1271alpha, a fungal metabolite, dose-dependently inhibited interleukin-1beta (IL-1beta) production in lipopolysaccharide (LPS)-stimulated human whole blood. Oral administration of LL-Z1271alpha to LPS-challenged mice caused significant lowering in the IL-1beta levels in peritoneal cavity. Data presented suggest that LL-Z1271alpha inhibits IL-1beta production by a novel mechanism as the inhibitory activity was not due to effects on caspase-1 (IL-1beta converting enzyme), the ATP-induced release mechanism or a lysosomotrophic effect.

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Cultured monocytes and macrophages stimulated with LPS produce large quantities of proIL-1beta, but release little mature cytokine to the medium. The efficiency at which the procytokine is converted to its active 17-kDa species and released extracellularly is enhanced by treating cytokine-producing cells with a secretion stimulus such as ATP or nigericin. To determine whether this need for a secretion stimulus extends to blood, individual donors were bled twice daily for 4 consecutive days, and the collected blood samples were subjected to a two-step IL-1 production assay.

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