RESUMO
Objective: To investigate the expression changes of Bcl-2-associated athanogene 1(BAG-1) and its regulatory effect on the glucocorticoid receptor(GR) activity in rat alveolar macrophages in conditions of cell inflammation and glucocorticoid therapy.Methods: The expression changes of BAG-1 were detected by Western blot after lipopolysaccharide(LPS) and Dexamethasone(Dex) treatment of rat alveolar macrophages(AMs),the interaction between BAG-1 and GR determined by immune coprecipitation experiment,and the transcriptional activation of GR measured by relative luciferase activity assay.Results:After LPS and Dex treatment,the expression of BAG-1L in total protein increased but that of BAG-1S remained changed,BAG-1L rather than BAG-1S was detected in nuclear protein and its expression increased gradually within 24 hours,the interaction between BAG-1L and GR was observed in nucleoli,and the transcriptional activation of GR decreased,with a negative correlation between BAG-1L expression and GR activity.Conclusion:LPS and Dex acting on rat alveolar macrophages,the expression of BAG-1L increases,which,coupled with GR,translocates into nucleoli and inhibits GR activity.This might be the important mechanism that underlies glucocorticoid resistance in inflammation.