Acute lung injury is reduced by the α7nAChR agonist PNU‐282987 through changes in the macrophage profile

Abstract

Nicotinic α‐7 acetylcholine receptor (nAChRα7) is a critical regulator of cholinergic anti‐inflammatory actions in several diseases, including acute respiratory distress syndrome(ARDS). Given the potential importance of α7nAChR as a therapeutic target, we evaluated whether PNU‐282987, an α7nAChR agonist, is effective in protecting the lung against inflammation. We performed intratracheal instillation of LPS to generate acute lung injury (ALI) in C57BL/6 mice. PNU‐282987 treatment, either before or after ALI induction, reduced neutrophil recruitment and IL‐ 1β, TNF‐α, IL‐6, keratinocyte chemoattractant (KC), and IL‐10 cytokine levels in the bronchoalveolar lavage fluid (P> 0.05). In addition, lung NF‐κB phosphorylation decreased, along with collagen fiber deposition and the number of matrix metalloproteinase‐9+ and −2+ cells, whereas the number of tissue inhibitor of metalloproteinase‐1+ cells increased (P < 0.05). PNU‐282987 treatment also reduced lung mRNA levels and the frequency of M1 macrophages, whereas cells expressing the M2‐related markers CD206 and IL‐10 increased, suggesting changes in the macrophage profile. Finally, PNU‐282987 improved lung function in LPS‐treated animals. The collective results suggest that PNU‐282987, anagonist of α7nAChR, reducesLPS‐induced experimental ALI, thus supporting the notion that drugs that act on α7nAChRs should be explored for ARDS treatment in humans.—Pinheiro, N. M., Santana, F. P. R., Almeida, R. R., Guerreiro, M., Martins, M.A., Caperuto, L.C., Câmara, N.O.S., Wensing, L.A., Prado, V. F., Tibério, I. F. L. C., Prado, M.A.M., Prado, C. M. Acute lung injury is reduced by the α7nAChR agonist PNU‐282987 through changes in the macrophage profile. FASEB J. 31, 320–332 (2017) www.fasebj.org