Basal autophagy maintains pancreatic acinar cell homeostasis and protein synthesis and prevents ER stress

L Antonucci, JB Fagman, JY Kim… - Proceedings of the …, 2015 - National Acad Sciences
Proceedings of the National Academy of Sciences, 2015National Acad Sciences
Pancreatic acinar cells possess very high protein synthetic rates as they need to produce
and secrete large amounts of digestive enzymes. Acinar cell damage and dysfunction cause
malnutrition and pancreatitis, and inflammation of the exocrine pancreas that promotes
development of pancreatic ductal adenocarcinoma (PDAC), a deadly pancreatic neoplasm.
The cellular and molecular mechanisms that maintain acinar cell function and whose
dysregulation can lead to tissue damage and chronic pancreatitis are poorly understood. It …
Pancreatic acinar cells possess very high protein synthetic rates as they need to produce and secrete large amounts of digestive enzymes. Acinar cell damage and dysfunction cause malnutrition and pancreatitis, and inflammation of the exocrine pancreas that promotes development of pancreatic ductal adenocarcinoma (PDAC), a deadly pancreatic neoplasm. The cellular and molecular mechanisms that maintain acinar cell function and whose dysregulation can lead to tissue damage and chronic pancreatitis are poorly understood. It was suggested that autophagy, the principal cellular degradative pathway, is impaired in pancreatitis, but it is unknown whether impaired autophagy is a cause or a consequence of pancreatitis. To address this question, we generated Atg7Δpan mice that lack the essential autophagy-related protein 7 (ATG7) in pancreatic epithelial cells. Atg7Δpan mice exhibit severe acinar cell degeneration, leading to pancreatic inflammation and extensive fibrosis. Whereas ATG7 loss leads to the expected decrease in autophagic flux, it also results in endoplasmic reticulum (ER) stress, accumulation of dysfunctional mitochondria, oxidative stress, activation of AMPK, and a marked decrease in protein synthetic capacity that is accompanied by loss of rough ER. Atg7Δpan mice also exhibit spontaneous activation of regenerative mechanisms that initiate acinar-to-ductal metaplasia (ADM), a process that replaces damaged acinar cells with duct-like structures.
National Acad Sciences