Targeting PCK2 alleviates GERD by suppressing MAPK-dependent endoplasmic reticulum stress and oxidative...

Gastroesophageal reflux disease (GERD) is a digestive disease characterized by endoplasmic reticulum stress (ERS) imbalance and oxidative stress-induced cellular injury. However, the key ERS-related regulators involved in GERD progression remain unclear. Here, we identified PCK2 as a novel GERD-associated ERS regulator and explored its role and underlying mechanisms in GERD development. Bioinformatics analysis of the GEO dataset GSE148381 identified four overlapping ERS-related candidate genes in GERD tissues. Among these candidates, PCK2 was selected based on its consistent upregulation in ABS-treated HET-1 A cells, as confirmed by RT-qPCR and western blotting, with a 1.2-fold increase in mRNA expression and a 2.67-fold increase in protein abundance compared with control cells. Functional studies demonstrated that PCK2 silencing attenuated ERS activation by reducing ATF6, PERK, p-PERK, CHOP, and XBP1 expression. PCK2 knockdown markedly alleviated oxidative stress, reducing ROS and MDA levels by approximately 91% and 34%, respectively, decreasing apoptosis by approximately 36%, and improving cell viability, whereas PCK2 overexpression exerted opposite effects. In vivo, PCK2 knockdown alleviated esophageal injury and suppressed ERS responses. Mechanistically, Gene Set Enrichment Analysis revealed enrichment of PCK2-associated genes in the MAPK pathway, and further experiments showed that PCK2 promoted p38 MAPK activation through enhanced p38 phosphorylation. Pharmacological inhibition of p38 signaling with SB203580 abolished PCK2-induced ERS, oxidative stress, and apoptosis in HET-1 A cells. Collectively, our findings indicate that PCK2 acts as a potential therapeutic target in GERD by promoting p38 MAPK activation, thereby exacerbating ERS, oxidative stress, and apoptosis.