Inhibition of insulin-like growth factor receptor-1 reduces necroptosis-related markers and attenuates LPS-induced lung injury in mice

Insulin-like growth factor-1 (IGF-1) levels are known to increase in the bronchoalveolar lavage fluid (BALF) of patients with acute respiratory distress syndrome. Herein, we investigated the role of IGF-1 in lipopolysaccharide (LPS)-induced lung injury. In LPS-treated cells, expressions of receptor-interacting protein 3 (RIP3) and phosphorylated mixed lineage kinase domain-like protein (MLKL) were decreased in IGF-1 receptor small interfering RNA (siRNA)-treated cells compared to control cells. The levels of pro-inflammatory cytokines including interleukin (IQ-1 beta(3, IL-6, IL-10, tumour necrosis factor-alpha, and macrophage inflammatory protein 2/C-X-C motif chemokine ligand 2 in the supernatant were significantly reduced in IGF-1 receptor siRNA-treated cells compared to control cells. In LPS-induced murine lung injury model, total cell counts, polymorphonuclear leukocytes counts, and pro inflammatory cytokine levels in the BALF were significantly lower and histologically detected lung injury was less common in the group treated with IGF-1 receptor monoclonal antibody compared to the non -treated group. On western blotting, RIP3 and phosphorylated MLKL expressions were relatively decreased in the IGF-1 receptor monoclonal antibody group compared to the non -treated group. IGF-1 may be associated with RIP3-mediated necroptosis in vitro, while blocking of the IGF-1 pathway may reduce LPS-induced lung injuries in vivo. (C) 2018 Elsevier Inc. All rights reserved.