Reprogramming of cholesterol sensing in epithelial cells supports pancreatic inflammation

Abstract

Pancreatitis is a common cause of hospitalization that necessitates attentive clinical management. Affected individuals are at risk for pancreatic cancer due to aberrant signaling and empowered cell plasticity. Yet, molecular and cellular dynamics that govern epithelial cell behavior in response to inflammation remain largely elusive.

Here we found that inflammation induces Endoplasmic Reticulum-Associated Degradation protein (ERAD)-mediated downregulation of Niemann-Pick type C protein 1 (NPC1), which leads to the sequestration of free cholesterol within acinar cells’ lysosomes. Reducing intra-pancreatic cholesterol levels through genetic ablation of Acly ameliorates cerulein-induced pancreatitis, while pharmacological targeting of NPC1 exacerbates tissue damage.

Mechanistically, the accumulation of lysosomal cholesterol is sensed by the mechanistic Target of Rapamycin Complex 1 (mTORC1) that promotes metaplasia of pancreatic acinar cells, an event commonly associated to pancreatitis and tissue regeneration. Indeed, cholesterol supplementation or NPC1 inhibition facilitate acinar-to-ductal metaplasia (ADM) both ex vivo and in vivo, in an mTORC1-dependent manner.

These results identify a metabolic/signaling axis driving the reprogramming of pancreatic epithelial cells in response to inflammation. This hinges on a nutrient sensing paradigm, previously documented exclusively in pathological conditions.