Excessive alcohol users have increased risk of developing respiratory infections in part due to oxidative stress-induced alveolar macrophage (AM) phagocytic dysfunction. Chronic ethanol exposure increases cellular oxidative stress in AM via upregulation of NADPH oxidase (Nox) 4, and treatment with the peroxisome proliferator-activated receptor gamma (PPARγ) ligand, rosiglitazone, decreased ethanol-induced Nox4. However, the mechanism by which ethanol induces Nox4 expression and PPARγ ligand reverses this defect has not been elucidated. Since microRNA (miR)-92a has been predicted to target Nox4 for destabilization, we hypothesized that ethanol exposure decreases miR-92a expression and leads to Nox4 upregulation. Previous studies have implicated mitochondrial-derived oxidative stress in AM dysfunction. We further hypothesized that ethanol increases mitochondrial-derived AM oxidative stress and dysfunction via miR-92a and that treatment with the PPARγ ligand, pioglitazone, could reverse these derangements. To test these hypotheses, a mouse AM cell line, MH-S cells, were exposed to ethanol in vitro and primary AM were isolated from a mouse model of chronic ethanol consumption to measure Nox4, mitochondrial target mRNA (qRT-PCR) and protein levels (confocal microscopy), mitochondria-derived reactive oxygen species (confocal immunofluorescence), mitochondrial fission (electron microscopy), and mitochondrial bioenergetics (extracellular flux analyzer). Ethanol exposure increased Nox4, enhanced mitochondria-derived oxidative stress, augmented mitochondrial fission, and impaired mitochondrial bioenergetics. Transfection with miR-92a mimic in vitro or pioglitazone treatment in vivo diminished Nox4 levels, resulting in improvements in these ethanol-mediated derangements. These findings provide support that pioglitazone may provide a novel therapeutic approach to mitigate ethanol-induced AM mitochondrial derangements.

过度饮酒会增加患呼吸道感染的风险，部分原因是氧化应激诱导的肺泡巨噬细胞 (AM) 吞噬功能障碍。慢性乙醇暴露通过上调 NADPH 氧化酶 (Nox) 4 增加 AM 中的细胞氧化应激，并用过氧化物酶体增殖物激活受体 γ (PPARγ) 配体罗格列酮治疗降低乙醇诱导的 Nox4。然而，乙醇诱导 Nox4 表达和 PPARγ 配体逆转这一缺陷的机制尚未阐明。由于已经预测 microRNA (miR)-92a 会靶向 Nox4 使其不稳定，我们假设乙醇暴露会降低 miR-92a 的表达并导致 Nox4 上调。以前的研究表明，线粒体衍生的氧化应激与 AM 功能障碍有关。我们进一步假设乙醇通过 miR-92a 增加线粒体衍生的 AM 氧化应激和功能障碍，并且用 PPARγ 配体吡格列酮治疗可以逆转这些紊乱。为了检验这些假设，将小鼠 AM 细胞系 MH-S 细胞暴露于乙醇中从慢性乙醇消耗小鼠模型中分离体外和原发性 AM，以测量 Nox4、线粒体靶 mRNA (qRT-PCR) 和蛋白质水平（共聚焦显微镜）、线粒体衍生的活性氧（共聚焦免疫荧光）、线粒体裂变（电子显微镜）和线粒体生物能量学（细胞外通量分析仪）。乙醇暴露增加了 Nox4，增强了线粒体衍生的氧化应激，增强了线粒体裂变，并损害了线粒体生物能量学。体外转染 miR-92a 模拟物或体内吡格列酮处理降低 Nox4 水平，从而改善这些乙醇介导的紊乱。这些发现支持吡格列酮可能提供一种新的治疗方法来减轻乙醇诱导的 AM 线粒体紊乱。