Chemical inhibition or genetic silencing of HO-1 significantly increases proinflammatory cytokine release, immune cell infiltration, and apoptosis, indicating that HO-1 has a protective role in LPS-induced ALI (Wiesel et al., 2000; Gong et al., 2008; Zhang Y. et al., 2013). Here, HMOX1 is linked to acute respiratory distress syndrome.