Upregulation of AQP4 can be triggered by a lipopolysaccharide (LPS)-triggered immune response (Alexander et al., 2008; Cao et al., 2012; Sugimoto et al., 2015), and heightened levels of AQP4 are thought to be a key mechanism of cellular edema in models of ischemic stroke (Papadopoulos et al., 2004; Warth et al., 2007; Yang et al., 2008). This evidence concerns the gene AQP4 and ischemic stroke.