Search

Objective: With the number of patients with acute pancreatitis (AP) increasing year by year, it is pressing to explore new key genes and markers for the treatment of AP. miR-455-3p/solute carrier family 2 member 1 (Slc2a1) obtained through bioinformatics analysis may participate in the progression of AP., Materials and Methods: The C57BL/6 mouse model of AP was constructed for subsequent studies. Through bioinformatics analysis, the differentially expressed genes related to AP were screened and hub genes were identified. A caerulein-induced AP animal model was constructed to detect the pathological changes of mouse pancreas by HE staining. The concentrations of amylase and lipase were measured. Primary mouse pancreatic acinar cells were isolated and subjected to microscopy to observe their morphology. The enzymatic activities of trypsin and amylase were detected. The secretion of inflammatory cytokines in mouse were measured with the ELISA kits of TNF- α , IL-6 and IL-1 β to determine pancreatic acinar cell damage. A binding site between the Slc2a1 3' UTR region and the miR-455-3p sequence was verified by dual-luciferase reporter assay. The expression of miR-455-3p was quantified by qRT-PCR, and Slc2a1 were detected by western blot., Results: A total of five (Fyn, Gadd45a, Sdc1, Slc2a1, and Src) were identified by bioinformatics analysis, and miR-455-3p/Slc2a1 were further studied. HE staining results showed that the AP models were successfully established by caerulein induction. In mice with AP, the expression of miR-455-3p was reduced, while that of Slc2a1 was increased. In the caerulein-induced cell model, the expression of Slc2a1 was significantly reduced after intervention of miR-455-3p mimics, whereas increased after miR-455-3p inhibitor treatment. miR-455-3p decreased the secretion of inflammatory cytokines in the cell supernatant, reduced the activity of trypsin and amylase, and alleviated the cell damage induced by caerulein. In addition, Slc2a1 3'UTR region was bound by miR-455-3p, and its protein expression was also regulated., Conclusion: miR-455-3p alleviated caerulein-induced mouse pancreatic acinar cell damage by regulating the expression of Slc2a1., Competing Interests: The authors declare there are no competing interests., (©2023 Zhan et al.)

Background & Aims: Pancreatitis is characterized by acinar cell death and persistent inflammation. Ferroptosis is a type of lipid peroxidation-dependent necrosis, which is negatively regulated by glutathione peroxidase 4. We studied how trypsin, a serine protease secreted by pancreatic acinar cells, affects the contribution of ferroptosis to triggering pancreatitis., Methods: In vitro, the mouse pancreatic acinar cell line 266-6 and mouse primary pancreatic acinar cells were used to investigate the effect of exogenous trypsin on ferroptosis sensitivity. Short hairpin RNAs were designed to silence gene expression, whereas a library of 1080 approved drugs was used to identify new ferroptosis inhibitors in 266-6 cells. In vivo, a Cre/LoxP system was used to generate mice with a pancreas-specific knockout of Gpx4 (Pdx1-Cre;Gpx4 flox/flox mice). Acute or chronic pancreatitis was induced in these mice (Gpx4 flox/flox mice served as controls) by cerulein injections or a Lieber-DeCarli alcoholic liquid diet. Pancreatic tissues, acinar cells, and serum were collected and analyzed by histology, immunoblot, quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, or immunohistochemical analyses., Results: Supraphysiological doses of trypsin (500 or 1000 ng/mL) alone did not trigger significant cell death in 266-6 cells and mouse primary pancreatic acinar cells, but did increase the sensitivity of these cells to ferroptosis upon treatment with cerulein, L-arginine, alcohol, erastin, or RSL3. Proteasome 26S subunit, non-adenosine triphosphatase 4-dependent lipid peroxidation caused ferroptosis in pancreatic acinar cells by promoting the proteasomal degradation of glutathione peroxidase 4. The drug screening campaign identified the antipsychotic drug olanzapine as an antioxidant inhibiting ferroptosis in pancreatic acinar cells. Mice lacking pancreatic Gpx4 developed more severe pancreatitis after cerulein infection or ethanol feeding than control mice. Conversely, olanzapine administration protected against pancreatic ferroptotic damage and experimental pancreatitis in Gpx4-deficient mice., Conclusions: Trypsin-mediated sensitization to ferroptotic damage increases the severity of pancreatitis in mice, and this process can be reversed by olanzapine., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Despite the proposal that somatostatin or its stable analogue, octreotide (SMS-201,995), may exert an ameliorating effect on acute pancreatitis, data concerning its beneficial effect in this situation are conflicting. This study examines the effects of octreotide on acute pancreatitis, resulting from the retrograde injection of a bile salt (taurocholate) plus saturating trypsin into the common bile-pancreatic duct of the rat. Octreotide given before the induction of pancreatitis significantly reduced the levels of serum amylase and lipase, ascites amylase concentration, degree of leukocyte infiltration, and focal areas of pancreatic tissue necrosis. In contrast, administration of octreotide as soon as 5 min following induction had no demonstrable ameliorating effects on the pancreatitis. These results indicate that octreotide may have application to prophylaxis of acute pancreatitis in cases where bile salts may play a role in pathogenesis, but may not be beneficial in established acute pancreatitis.

Experimental pancreatitis induced by permanently closed duodenal loop results in death of the experimental animal. Acute pancreatitis can be induced in the rat by injection of taurocholate sodium-trypsin solution intraluminally into a temporarily occluded duodenal loop. Mortality in this model was 45% within one week after injection. Mean serum amylase level was greatly increased above that in control rats that underwent temporary duodenal ligation without intraduodenal injection of fluid. The presence of pancreatitis was confirmed by histological examination. The advantage of the temporarily occluded pancreatitis model is that the animal can survive if the stimulus is not excessively severe.