SMAD3 and gastroesophageal reflux disease: Long-term exposure to GERD can cause the upregulation of TGF-β1, Smad-3, α-SMA, and type I collagen in the esophageal epithelium of mice, promoting the expression levels of ROS, NADPH oxidase-4, and malondialdehyde (Yisireyili et al., 2019).