Mahida Rahul Y, Scott Aaron, Parekh Dhruv, Lugg Sebastian T, Belchamber Kylie B R, Hardy Rowan S, Matthay Michael A, Naidu Babu, Thickett David R
Birmingham Acute Care Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom.
Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom.
Front Med (Lausanne). 2021 Sep 29;8:737859. doi: 10.3389/fmed.2021.737859. eCollection 2021.
Impaired alveolar macrophage (AM) efferocytosis may contribute to acute respiratory distress syndrome (ARDS) pathogenesis; however, studies are limited by the difficulty in obtaining primary AMs from patients with ARDS. Our objective was to determine whether an model of ARDS can recapitulate the same AM functional defect observed and be used to further investigate pathophysiological mechanisms. AMs were isolated from the lung tissue of patients undergoing lobectomy and then treated with pooled bronchoalveolar lavage (BAL) fluid previously collected from patients with ARDS. AM phenotype and effector functions (efferocytosis and phagocytosis) were assessed by flow cytometry. Rac1 gene expression was assessed using quantitative real-time PCR. ARDS BAL treatment of AMs decreased efferocytosis ( = 0.0006) and Rac1 gene expression ( = 0.016); however, bacterial phagocytosis was preserved. Expression of AM efferocytosis receptors MerTK ( = 0.015) and CD206 ( = 0.006) increased, whereas expression of the antiefferocytosis receptor SIRPα decreased following ARDS BAL treatment ( = 0.036). Rho-associated kinase (ROCK) inhibition partially restored AM efferocytosis in an model of ARDS ( = 0.009). Treatment of lung resection tissue AMs with ARDS BAL fluid induces impairment in efferocytosis similar to that observed in patients with ARDS. However, AM phagocytosis is preserved following ARDS BAL treatment. This specific impairment in AM efferocytosis can be partially restored by inhibition of ROCK. This model of ARDS is a useful tool to investigate the mechanisms by which the inflammatory alveolar microenvironment of ARDS induces AM dysfunction.
肺泡巨噬细胞（AM）的胞葬作用受损可能导致急性呼吸窘迫综合征（ARDS）的发病机制；然而，由于难以从ARDS患者中获取原代AM，相关研究受到限制。我们的目的是确定ARDS模型是否能重现观察到的相同AM功能缺陷，并用于进一步研究病理生理机制。从接受肺叶切除术的患者肺组织中分离出AM，然后用先前从ARDS患者收集的支气管肺泡灌洗（BAL）混合液进行处理。通过流式细胞术评估AM表型和效应器功能（胞葬作用和吞噬作用）。使用定量实时PCR评估Rac1基因表达。ARDS BAL处理AM可降低胞葬作用（P = 0.0006）和Rac1基因表达（P = 0.016）；然而，细菌吞噬作用得以保留。ARDS BAL处理后，AM胞葬作用受体MerTK（P = 0.015）和CD206（P = 0.006）的表达增加，而抗胞葬作用受体SIRPα的表达降低（P = 0.036）。在ARDS模型中，Rho相关激酶（ROCK）抑制可部分恢复AM胞葬作用（P = 0.009）。用ARDS BAL液处理肺切除组织AM可诱导胞葬作用受损，类似于在ARDS患者中观察到的情况。然而，ARDS BAL处理后AM吞噬作用得以保留。AM胞葬作用的这种特异性损伤可通过抑制ROCK部分恢复。这种ARDS模型是研究ARDS炎症性肺泡微环境诱导AM功能障碍机制的有用工具。
