Abstract 12320: Inhibition of DNA Methylation and Histone Acetylation Changes the Macrophage Polarization During Endotoxemia-induced Lung Injury

Abstract

Introduction: Acute lung injury (ALI) during sepsis is characterized by bilateral alveolar infiltrates, lung edema, and respiratory failure. The exact molecular mechanism for ALI is poorly understood. Although chemical epigenetic modifiers can potentially limit lung inflammation, to date no study has examined the efficacy of DNA methyl transferase inhibitor 5-Aza 2-deoxycytidine (Aza) and histone deacetylase inhibitor Trichostatin A (TSA) combination therapy (Aza+TSA) on the polarization of macrophages. Hypothesis: We hypothesized that therapy with Aza+TSA would reduce inflammation in ALI and will stimulate the production of M2 macrophages. Methods and Results: In LPS-induced mouse ALI, post-treatment with a single dose of Aza+TSA showed a substantial attenuation of adverse lung inflammation and histopathological changes. Flow cytometry data showed a significant decrease in expression of CD14 and CD40, and increased expression of CD23 and CD124 in Aza+TSA-treated cells compared with untreated LPS-induced primary bone marrow derived macrophages (BMDMs) or LPS-induced BMDMs treated with either drug alone (Fig panel A). This was further confirmed by Western analysis for M1 marker NOS2 and M2 marker CD206. Our data showed lesser expression of NOS2 (Fig panel B) and higher expression of CD206 (Fig panel C) in LPS-challenged BMDMs treated with Aza+TSA than in the BMDMs treated with either Aza or TSA alone. These data support that Aza+TSA treatment promotes an M2 phenotype in LPS-stimulated macrophages, which secrete anti-inflammatory cytokines. Conclusions: This novel treatment with combined epigenetic modifiers has therapeutic potential for patients with sepsis-induced ALI by reducing inflammation and generation of alternatively activated M2 macrophages with more abilities of pathogen clearance.