Macrophage activation may play a crucial role in the increased susceptibility of obese individuals to acute lung injury (ALI). Dysregulation of miRNA, which is involved in various inflammatory diseases, is often observed in obesity. This study aimed to investigate the role of miR-192 in lipopolysaccharide (LPS)-induced ALI in obese mice and its mechanism of dysregulation in obesity. Human lung tissues were obtained from obese patients (BMI ≥ 30.0 kg/m2) and control patients (BMI 18.5–24.9 kg/m2). An obese mouse model was established by feeding a high-fat diet (HFD), followed by intratracheal instillation of LPS to induce ALI. Pulmonary macrophages of obese mice were depleted through intratracheal instillation of clodronate liposomes. The expression of miR-192 was examined in lung tissues, primary alveolar macrophages (AMs), and the mouse alveolar macrophage cell line (MH-S) using RT-qPCR. m6A quantification and RIP assays helped determine the cause of miR-192 dysregulation. miR-192 agomir and antagomir were used to investigate its function in mice and MH-S cells. Bioinformatics and dual-luciferase reporter gene assays were used to explore the downstream targets of miR-192. In obese mice, depletion of macrophages significantly alleviated lung tissue inflammation and injury, regardless of LPS challenge. miR-192 expression in lung tissues and alveolar macrophages was diminished during obesity and further decreased with LPS stimulation. Obesity-induced overexpression of FTO decreased the m6A modification of pri-miR-192, inhibiting the generation of miR-192. In vitro, inhibition of miR-192 enhanced LPS-induced polarization of M1 macrophages and activation of the AKT/ NF-κB inflammatory pathway, while overexpression of miR-192 suppressed these reactions. BIG1 was confirmed as a target gene of miR-192, and its overexpression offset the protective effects of miR-192. In vivo, when miR-192 was overexpressed in obese mice, the activation of pulmonary macrophages and the extent of lung injury were significantly improved upon LPS challenge. Our study indicates that obesity-induced downregulation of miR-192 expression exacerbates LPS-induced ALI by promoting macrophage activation. Targeting macrophages and miR-192 may provide new therapeutic avenues for obesity-associated ALI.

中文翻译：

---

肥胖诱导的 miR-192 下调通过促进巨噬细胞活化加剧脂多糖诱导的急性肺损伤

巨噬细胞的激活可能在肥胖个体对急性肺损伤（ALI）的易感性增加中发挥着至关重要的作用。miRNA 失调与多种炎症性疾病有关，经常在肥胖症中观察到。本研究旨在探讨miR-192在脂多糖（LPS）诱导的肥胖小鼠ALI中的作用及其在肥胖中的失调机制。人肺组织取自肥胖患者（BMI ≥ 30.0 kg/m2）和对照患者（BMI 18.5-24.9 kg/m2）。采用高脂饮食（HFD）喂养，然后气管内滴注LPS诱导ALI的肥胖小鼠模型。通过气管内滴注氯膦酸盐脂质体来消耗肥胖小鼠的肺巨噬细胞。使用 RT-qPCR 检查肺组织、原代肺泡巨噬细胞 (AM) 和小鼠肺泡巨噬细胞系 (MH-S) 中 miR-192 的表达。m6A 定量和 RIP 测定有助于确定 miR-192 失调的原因。miR-192 agomir 和 antagomir 用于研究其在小鼠和 MH-S 细胞中的功能。使用生物信息学和双荧光素酶报告基因测定来探索 miR-192 的下游靶标。在肥胖小鼠中，无论 LPS 攻击如何，巨噬细胞的消耗都显着减轻了肺组织炎症和损伤。肺组织和肺泡巨噬细胞中的 miR-192 表达在肥胖期间减少，并且随着 LPS 刺激而进一步减少。肥胖诱导的 FTO 过度表达减少了 pri-miR-192 的 m6A 修饰，从而抑制了 miR-192 的产生。在体外，抑制 miR-192 增强了 LPS 诱导的 M1 巨噬细胞极化和 AKT/NF-κB 炎症通路的激活，而 miR-192 的过表达则抑制这些反应。BIG1被证实是miR-192的靶基因，其过表达抵消了miR-192的保护作用。在体内，当肥胖小鼠中miR-192过表达时，LPS攻击后肺巨噬细胞的活化和肺损伤程度显着改善。我们的研究表明，肥胖诱导的 miR-192 表达下调会通过促进巨噬细胞活化而加剧 LPS 诱导的 ALI。靶向巨噬细胞和 miR-192 可能为肥胖相关 ALI 提供新的治疗途径。