Pioglitazone improves alcohol-induced alveolar macrophage phagocytic dysfunction via increases in microRNAs-1264 and -107.

Abstract

Abstract Objective: People with a history of alcohol use disorders (AUD) are 2–4 times more likely to develop lung infections, in part due to impaired alveolar macrophage (AM) immune function. Ethanol (EtOH) induces oxidative stress via increases in NAPDH oxidase (Nox)1 and Nox2 and decreases in peroxisome proliferator-activated receptor (PPAR)γ, leading to AM phagocytic dysfunction. Since PPARγ activation with its ligand pioglitazone (PIO) attenuated acute lung injury, we hypothesized that PIO upregulates Nox1-related microRNA (miR)-1264 and Nox2-related miR-107, thereby lowering Nox1 and Nox2 expression and oxidative stress and improving AM phagocytic function. Methods: AM were isolated from C57BL/6J mice fed EtOH (20% w/v) in the drinking water for 12 wks ± PIO (10 mg/kg/day by oral gavage during week 12). In parallel, a mouse AM cell line, MH-S cells, were transfected ± 50 nM miR-1264/-107 mimics and treated ± 0.08% EtOH for 3 d ± 10 μM PIO on day 3. miR-1264 and -107 were assessed by qRT-PCR. Nox1 and Nox2 mRNA and protein levels were measured by qRT-PCR and cytoimmunostaining. Oxidative stress was assessed with DCFH-DA and Amplex Red assays. AM phagocytosis was evaluated by S. aureus internalization. Results: In vivo and in vitro, EtOH: decreased miR-1264/-107 levels, increased Nox1 and Nox2 expression, enhanced oxidative stress, and impaired phagocytosis. miR-1264/-107 mimics or PIO reversed these EtOH-induced AM derangements. Conclusions: PIO rapidly upregulated miRs-1264/-107 and attenuated EtOH-induced AM oxidative stress and phagocytic dysfunction. Our studies suggest PIO as a clinically relevant intervention to mitigate AM immune derangements and may decrease susceptibility of lung infections in people with a history of AUD.