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

Nicotinic alpha-7 acetylcholine receptor (nAChR alpha 7) is a critical regulator of cholinergic anti-inflammatory actions in several diseases, including acute respiratory distress syndrome (ARDS). Given the potential importance of alpha 7nAChR as a therapeutic target, we evaluated whether PNU-282987, an alpha 7nAChR agonist, is effective in protecting the lung against inflammation. We performed intratracheal instillation of LPS to generate acute lung injury (ALI) in C57BL/6mice. PNU-282987 treatment, either before or after ALI induction, reduced neutrophil recruitment and IL1 beta, TNF-alpha, IL-6, keratinocyte chemoattractant (KC), and IL-10 cytokine levels in the bronchoalveolar lavage fluid (P<0.05). In addition, lung NF-kappa B 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 alpha 7nAChR, reduces LPS-induced experimental ALI, thus supporting the notion that drugs that act on alpha 7nAChRs 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., Camara, N. O. S., Wensing, L. A., Prado, V. F., Tiberio, I. F. L. C., Prado, M. A. M., Prado, C. M. Acute lung injury is reduced by the alpha 7nAChR agonist PNU-282987 through changes in the macrophage profile.