Chronic Gastroesophageal Reflux Dysregulates Proteostasis in Esophageal Epithelial Cells.

Background & Aims: Gastroesophageal reflux disease (GERD) is a common digestive disorder that is characterized by esophageal tissue damage produced by exposure of the esophageal lining to the gastric refluxate. GERD can raise the risk of multiple serious complications including esophageal tumors. At the molecular levels, GERD-affected tissues are characterized by strong oxidative stress and the formation of reactive isolevuglandins (isoLGs). These products of lipid peroxidation rapidly interact with cellular proteins forming protein adducts. Here, we investigated the interrelationship between isoLG adduction and aggregation of cellular proteins.

Methods: Protein misfolding and aggregation were analyzed using multiple protein misfolding and aggregation assays. Pathologic consequences of protein adduction and aggregation were studied using human and murine esophageal tissues. Surgical model of esophageal reflux injury and L2-IL1β transgenic mice were used to investigate the mechanisms of protein misfolding and aggregation.

Results: Our studies demonstrate that gastroesophageal reflux causes protein misfolding and aggregation that is associated with severity of GERD. Dysregulation of proteostasis induces ferroptotic cell death and is mediated by modification of cellular proteins with reactive isoLGs that can be prevented by isoLG scavengers.

Conclusions: GERD causes dysregulation of cellular proteostasis, accumulation of isoLG protein adducts, misfolded, and aggregated proteins that promote ferroptotic cell death. Taken together, this study suggests that GERD has similarities to other known pathologic conditions that are characterized by protein misfolding and aggregation.