ABSTRACT
Objective:To study the effect of erythromycin(EM) on cigarette smoke-induced histone deacetylase-3(HDAC3) protein expression in human macrophages in vitro .Methods:The Aqueous cigarette smoke extract ( CSE) was always prepared fresh on the day of the experiment .The U937 monocytic cells were differentiated into macrophages by using phorbol 12-myristate 13-acetate (PMA) according to standard procedures .The U937 differentiated cells were treated with either CSE (1%) or EM (1 μg/ml) pre-treatment, and HDAC inhibitor trichostatin A (TSA;100 ng/ml) for 24 h.HDAC activity was measured with a colorimetric assay kit and Western blot was used for HDAC3 and factor nuclear-kappaB (NF-κB) protein assays.The levels of tumor necrosis factor-α(TNF-α) release in the supernatant were determined by enzyme linked immunosorbent assay (ELISA).Results:CSE(1%) significantly de-creased HDAC activity and HDAC 3 protein levels at 24 h.Preincubation with EM (1μg/ml ) for 24 h significantly inhibit CSE (1%) induced decrease of HDAC3 protein expression.Furthermore, Preincubation with EM(1 μg/ml) for 24 h significantly inhibit NF-κB activity and TNF-αrelease in human macrophages .Conclusion:EM is able to restore HDAC3 levels decreased by cigarette smoke and inhibit NF-κB activity resulting in decreasing CSE-mediated TNF-αrelease, which has shown an important explanation that EM possess the anti-inflammatory effect induced by cigarette smoke .