Curcumin alleviates macrophage activation and lung inflammation induced by influenza virus infection through inhibiting the NF‐κB signaling pathway

BACKGROUND Influenza A viruses (IAV) result in severe public health problems with worldwide each year. Overresponse of immune system to IAV infection leads to complications, and ultimately causing morbidity and mortality. OBJECTIVE Curcumin has been reported to have anti-inflammatory ability. However, its molecular mechanism in immune responses remains unclear. METHODS We detected the pro-inflammatory cytokine secretion and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB)-related protein expression in human macrophages or mice infected by IAV with or without curcumin treatment. RESULTS We found that the IAV infection caused a dramatic enhancement of pro-inflammatory cytokine productions of human macrophages and mice immune cells. However, curcumin treatment after IAV infection downregulated these cytokines production in a dose-dependent manner. Moreover, the NF-κB has been activated in human macrophages after IAV infection, while administration of curcumin inhibited NF-κB signaling pathway via promoting the expression of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), and inhibiting the translocation of p65 from cytoplasm to nucleus. CONCLUSIONS In summary, IAV infection could result in the inflammatory responses of immune cells, especially macrophages. Curcumin has the therapeutic potentials to relieve these inflammatory responses through inhibiting the NF-κB signaling pathway.