Anti-inflammatory Effects of Neuregulin-1 via the Downregulation of IL-6, IL-8, and MCP-1 Secretion

The trophic factor Neuregulin-1 (NRG-1) plays a critical role in the development of the peripheral nervous system and the repair of nerve injuries. The regulation of neutrophil apoptosis by cytokine secretion from structural cells is an important process in inflammatory diseases, including asthma. This study aimed to investigate the relationship between NRG-1 and the alteration of neutrophil apoptosis by the regulation of cytokine release in the human lung epithelial BEAS-2B cells. Tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) induce the increase in the release of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1). NRG-1 alone had no effect on the secretion of IL-6, IL-8, and MCP-1. However, co-treatment of TNF-α and IFN-γ with NRG-1 inhibited the secretion of IL-6, IL-8, and MCP-1 that had been increased by TNF-α and IFN-γ. Treatment with NRG-1 did not have a direct effect on neutrophil apoptosis. Co-treatment of TNF-α and IFN-γ with NRG-1 was not effective on suppression of neutrophil apoptosis due to TNF-α and IFN-γ. The supernatant of BEAS-2B cells after co-treatment of TNF-α and IFN-γ with NRG-1 suppressed the inhibition of neutrophil apoptosis that had been caused due to the supernatant treated with TNF-α and IFN-γ. Taken together, NRG-1 has an anti-inflammatory effect in an inflammatory milieu by the regulation of cytokine secretion and neutrophil apoptosis.