AQP5 and xerostomia: While AQP5 knock-out mice have no discernable difference in baseline phenotype, changes in AQP5 have been implicated in the pathogenesis of acute lung injury, as well as in the development of xerostomia, lung submucosal glandular secretions, and in the regulation of sweat (Song and Verkman, 2001; Verkman, 2007; Inoue, 2016; Zhang J. et al., 2018; Hosoi et al., 2020).