The Role Of FOXO3 In Nonerosive Reflux Disease

Purpose: Transcriptomic studies on gastroesophageal reflux disease are scarce,and gene expression signatures in nonerosive reflux disease(NERD)remain elusive.The aim of the study was to identify gene expression profiles in NERD.Patients and Methods: We performed RNA sequencing on biopsy samples from nine consecutive patients with NERD and six healthy controls.Differentially expressed genes(DEGs)were analysed with the DESeq2 R package.Cytoscape and Metascape were used to perform DEG functional and signaling pathway enrichment analysis.Results: In total,1195 DEGs were identified,including 649 upregulated and 546 downregulated genes involved in regulating the inflammatory response and epithelial cell differentiation.Conclusion: The DEGs may be involved in the development of NERD.Identification of transcriptomic landscape provides a starting place for the search for critical genes in the pathogenesis of NERD.Purpose: Current evidence indicates that the epithelial barrier is a key target for protecting against reflux-induced damage.Mitochondrial function has been regarded as a gatekeeper of epithelial cell homeostasis.However,its role and underlying mechanisms in gastroesophageal reflux disease remain largely elusive.Studies have shown that FOXO3 is closely related to the regulation of mitochondrial function.RNA sequencing revealed an aberrant expression of FOXO3 in nonerosive reflux disease(NERD).Here,we aimed to explore the molecular mechanisms of FOXO3 in attenuating reflux-induced mitochondrial dysfunction and epithelial barrier disruption.Methods: Hematoxylin-eosin staining and transmission electron microscopy were used to examine reflux-induced damage in the esophageal epithelium.FOXO3 was assayed in human esophageal biopsy samples and mouse models of mixed reflux by western blot and quantitive polymerase chain reaction.The role of FOXO3 on its putative target gene,NDRG1,was further studied in esophageal epithelial cells.Results: Abnormal mitochondrial morphology and compromised epithelial barrier were observed in mouse surgical models.FOXO3 was expressed in the normal esophageal epithelium and activated in NERD and mouse models of mixed reflux.FOXO3-mediated inhibition of mitochondrial fission alleviated weakly acidic bile salt mediuminduced mitochondrial dysfunction,oxidative stress,and impaired epithelial barrier function.Further experiments confirmed that FOXO3 improved mitochondrial dynamics by transcriptionally regulating NDRG1 in esophageal epithelial cells.Additionally,downregulation of NDRG1 abolished the therapeutic effect of FOXO3 in mitochondrial function and epithelial barrier function.Conclusion: Gastroesophageal reflux activated FOXO3 in the esophageal epithelium as a defense mechanism.FOXO3 overexpression sustained the mitochondrial network and mitochondrial function and thereby protected esophageal epithelium against refluxinduced epithelial barrier dysfunction.