Serine Stabilizes SLC7A11 and Enhances Cystine Influx to Protect Against Acute Pancreatitis

Lethal sterile inflammatory diseases are linked to amino acid metabolism, but the role of serine remains unclear. Here, we show that dysregulated serine metabolism and reduced plasma serine levels correlate with disease severity of acute pancreatitis (AP) in patients and mouse models. Elevating serine levels via exogenous serine supplementation or pancreatic phosphoglycerate dehydrogenase (PHGDH) overexpression mitigates pancreatic injury, whereas a serine deprivation diet or pancreatic PHGDH knockdown exacerbates AP. Serine prevents cell death and oxidative stress in pancreatic acinar cells, human induced pluripotent stem cells-derived pancreatic organoids and mouse pancreatic tissue. Serine enhances cysteine and glutathione biosynthesis primarily by promoting solute carrier family 7 member 11 (SLC7A11)-dependent cystine uptake rather than by serving as a direct substrate. Mechanistically, the E3 ubiquitin ligase NEDD4 mediates ubiquitination and degradation of SLC7A11, whereas serine binds to NEDD4 and thereby inhibits SLC7A11 degradation. Similarly to serine, pharmacological inhibition of NEDD4 alleviates lipid peroxidation and pancreatic injury. These findings identify serine as a critical signaling regulator of SLC7A11 stability and oxidative stress, and provides a new therapeutic strategy for AP and associated sterile inflammatory disorders. HighlightsAcute pancreatitis (AP) is linked to abnormal serine metabolism and serine depletion. Serine prevents cell death in AP acinar cells, human pancreatic organoids and mice. Serine promotes SLC7A11-dependent cystine uptake and glutathione levels in acinar cells. Serine reduces NEDD4-mediated ubiquitination of SLC7A11. In briefSerine protects against cell death and pancreatic injury in acute pancreatitis by stabilizing SLC7A11 through disruption of NEDD4-mediated ubiquitination in acinar cells.