Background: Chronic Pancreatitis (CP) is a long-term risk factor for pancreatic ductal adenocarcinoma (PDAC), and both diseases share a common etiology. The activation of Pancreatic stellate cells (PaSCs) caused by inflammation of the chronic pancreas plays a pivotal role in the pathology of pancreatic fibrosis and the malignant phenotype of PDAC. However, the central role of activated PaSCs in Acinar-to-Ductal Metaplasia (ADM) remains unknown.
Objective: In the present study, we investigated the link between pancreatic fibrosis and ADM and the possible underlying mechanism.
Methods: A caerulein-treated mouse CP model was established, and Masson trichrome histochemical stain and Transmission Electron Microscope (TEM) were used to observe stromal fibrosis and cell ultrastructure, respectively. The expression of amylase and cytokeratin 19 (CK19), mitochondria respiration, and reactive oxygen species (ROS) were detected in vitro in the co-culture model of primary pancreatic acinar cells and PaSCs.
Results: The activation of PaSCs and pancreatic fibrosis were accompanied by ADM in pancreatic parenchyma in caerulein-treated mice, which was verified by the co-cultivation experiment in vitro. Furthermore, we showed that activated PaSCs promote ADM by disrupting mitochondrial respiration and releasing ROS. The expression of inflammation-and ADM-related genes, including S100A8, S100A9, and CK19, was observed to be up-regulated in pancreatic acinar cells in the presence of activated PaSCs. The expression of S100A9 and CK19 proteins was also up-regulated in acinar cells co-cultured with activated PaSCs.
Conclusion: The manipulation of mitochondrial respiration and ROS release is a promising preventive and/or therapeutic strategy for PDAC, and S100A9 is expected to be a therapeutic target to block the ADM process induced by the activation of PaSCs.
Keywords: Pancreatic stellate cells, acinar-to-duct metaplasia, mitochondrial respiration, reactive oxygen species, S100A9, ROS, CP.