Bis-N-norgliovictin, a small-molecule compound from marine fungus, inhibits LPS-induced inflammation in macrophages and improves survival in sepsis

Abstract

Sepsis is a highly lethal disorder characterized by systemic inflammation, and Toll-like receptor 4 (TLR4) in macrophages plays a crucial role in modulating innate immune response and outcome of sepsis. During the screening of natural products against inflammation, we identified bis-N-norgliovictin, a small-molecule compound isolated from marine-derived fungus, significantly inhibited lipopolysaccharide (LPS, ligand of TLR4)-induced tumor necrosis factor-α (TNF-α) production in RAW264.7 cells. In this study, we evaluated the effect of bis-N-norgliovictin on TLR4-mediated inflammation in mouse macrophages and LPS-induced sepsis model. In RAW264.7 and mouse peritoneal macrophages, bis-N-norgliovictin dose-dependently inhibited LPS-induced production of TNF-α, interleukin-6 (IL-6), interferon-β (IFN-β) and monocyte chemoattractant protein (MCP-1), but without suppressing cell viability. The anti-inflammatory effect was attributed to the down-regulation of TLR4-triggered myeloid differentiation primary response protein 88 (MyD88)-dependent and TIR-containing adapter inducing interferon-β (TRIF)-dependent signaling pathways, including p38 and c-Jun N-terminal kinase (JNK) of mitogen-activated protein kinases (MAPKs), nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3) cascades. Importantly, bis-N-norgliovictin also protected mice against LPS-induced endotoxic shock. Intravenous injection of bis-N-norgliovictin 1h before LPS challenge dose-dependently inhibited LPS-induced increases in serum levels of TNF-α, IL-6, MCP-1 and IL-10, attenuated liver and lung injury and diminished M1 macrophage polarization in liver. Our results demonstrate that bis-N-norgliovictin exhibit potent anti-inflammatory effect both in vitro and in vivo. These findings suggest that bis-N-norgliovictin can be a useful therapeutic candidate for the treatment of sepsis and other inflammatory diseases.