ABSTRACT
A series of betamethasone 17alpha-carbamates were designed, synthesized, and evaluated for their ability to dissociate the two main functions of the glucocorticoid receptor, that is, transactivation and transrepression, in rat cell lines. A number of alkyl substituted betamethasone 17alpha-carbamates were identified with excellent affinity for the glucocorticoid receptor (e.g., 7, GR IC(50) 5.1 nM) and indicated dissociated profiles in functional assays of transactivation (rat tyrosine aminotransferase, TAT, and rat glutamine synthetase, GS) and transrepression (human A549 cells, MMP-1 assay). Gratifyingly, the in-vivo profile of these compounds, for example, 7, also indicated potent anti-inflammatory activity with impaired effects on glucose, insulin, triglycerides, and body weight. Taken together, these results indicate that dissociated glucocorticoid receptor modulators can be identified in rodents.
Subject(s)
Betamethasone/analogs & derivatives , Carbamates/chemical synthesis , Receptors, Glucocorticoid/metabolism , Animals , Anti-Inflammatory Agents/chemical synthesis , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacokinetics , Anti-Inflammatory Agents/pharmacology , Betamethasone/chemical synthesis , Betamethasone/pharmacokinetics , Betamethasone/pharmacology , Blood Glucose/metabolism , Body Weight/drug effects , Carbamates/chemistry , Carbamates/pharmacokinetics , Carbamates/pharmacology , Glutamate-Ammonia Ligase/metabolism , Insulin/blood , Liver/drug effects , Liver/metabolism , Matrix Metalloproteinase 1/metabolism , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Rats , Receptors, Glucocorticoid/chemistry , Triglycerides/blood , Tyrosine Transaminase/metabolismABSTRACT
The p38 MAP kinase signal transduction pathway is an important regulator of proinflammatory cytokine production and inflammation. Defining the roles of the various p38 family members, specifically p38alpha and p38beta, in these processes has been difficult. Here we use a chemical genetics approach using knock-in mice in which either p38alpha or p38beta kinase has been rendered resistant to the effects of specific inhibitors along with p38beta knock-out mice to dissect the biological function of these specific kinase isoforms. Mice harboring a T106M mutation in p38alpha are resistant to pharmacological inhibition of LPS-induced TNF production and collagen antibody-induced arthritis, indicating that p38beta activity is not required for acute or chronic inflammatory responses. LPS-induced TNF production, however, is still completely sensitive to p38 inhibitors in mice with a T106M point mutation in p38beta. Similarly, p38beta knock-out mice respond normally to inflammatory stimuli. These results demonstrate conclusively that specific inhibition of the p38alpha isoform is necessary and sufficient for anti-inflammatory efficacy in vivo.
