NOX4 and pulmonary fibrosis: In addition, Cos attenuates heat‐killed Staphylococcus aureus‐induced acute lung injury via inhibition of macrophage activation and displays anti‐fibrotic activity in bleomycin‐induced pulmonary fibrosis by regulating NF‐κB and Nrf‐2/NADPH oxidase 4 (NOX4) signalling pathways.9, 10