Expression of human cationic trypsinogen (PRSS1) in murine acinar cells promotes pancreatitis and apoptotic cell death.
Hereditary pancreatitis (HP) is an autosomal dominant disease that displays the features of both acute and chronic pancreatitis. Mutations in human cationic trypsinogen (PRSS1) are associated with HP and have provided some insight into the pathogenesis of pancreatitis, but mechanisms responsible for the initiation of pancreatitis have not been elucidated and the role of apoptosis and necrosis has been much debated. However, it has been generally accepted that trypsinogen, prematurely activated within the pancreatic acinar cell, has a major role in the initiation process. Functional studies of HP have been limited by the absence of an experimental system that authentically mimics disease development. We therefore developed a novel transgenic murine model system using wild-type (WT) human PRSS1 or two HP-associated mutants (R122H and N29I) to determine whether expression of human cationic trypsinogen in murine acinar cells promotes pancreatitis. The rat elastase promoter was used to target transgene expression to pancreatic acinar cells in three transgenic strains that were generated: Tg(Ela-PRSS1)NV, Tg(Ela-PRSS1*R122H)NV and Tg(Ela-PRSS1*N29I)NV. Mice were analysed histologically, immunohistochemically and biochemically. We found that transgene expression is restricted to pancreatic acinar cells and transgenic PRSS1 proteins are targeted to the pancreatic secretory pathway. Animals from all transgenic strains developed pancreatitis characterised by acinar cell vacuolisation, inflammatory infiltrates and fibrosis. Transgenic animals also developed more severe pancreatitis upon treatment with low-dose cerulein than controls, displaying significantly higher scores for oedema, inflammation and overall histopathology. Expression of PRSS1, WT or mutant, in acinar cells increased apoptosis in pancreatic tissues and isolated acinar cells. Moreover, studies of isolated acinar cells demonstrated that transgene expression promotes apoptosis rather than necrosis. We therefore conclude that expression of WT or mutant human PRSS1 in murine acinar cells induces apoptosis and is sufficient to promote spontaneous pancreatitis, which is enhanced in response to cellular insult.
Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK.
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T
Athwal
1] Liverpool NIHR Pancreas Biomedical Research Unit, Royal Liverpool University Hospital, University of Liverpool, Liverpool, UK [2] Sichuan Provincial Pancreatitis Centre, West China Hospital, Sichuan University, Chengdu, China.
W
W
Huang
Liverpool NIHR Pancreas Biomedical Research Unit, Royal Liverpool University Hospital, University of Liverpool, Liverpool, UK.
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R
Mukherjee
Liverpool NIHR Pancreas Biomedical Research Unit, Royal Liverpool University Hospital, University of Liverpool, Liverpool, UK.
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D
Latawiec
Department of Cellular and Molecular Physiology, Institute for Translational Medicine, University of Liverpool, Liverpool, UK.
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M
Chvanov
Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK.
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R
Clarke
Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK.
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K
Smith
Department of Pathology, Royal Liverpool University Hospital, Liverpool, UK.
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F
Campbell
Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK.
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C
Merriman
Department of Cellular and Molecular Physiology, Institute for Translational Medicine, University of Liverpool, Liverpool, UK.
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D
Criddle
1] Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK [2] Liverpool NIHR Pancreas Biomedical Research Unit, Royal Liverpool University Hospital, University of Liverpool, Liverpool, UK.
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R
Sutton
1] Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK [2] Liverpool NIHR Pancreas Biomedical Research Unit, Royal Liverpool University Hospital, University of Liverpool, Liverpool, UK.
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J
Neoptolemos
Department of Molecular and Clinical Cancer Medicine, Institute for Translational Medicine, University of Liverpool, Cancer Research Centre, Liverpool, UK.
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N
Vlatković
D061354:Acinar Cells / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D017209:Apoptosis; D002108:Ceruletide; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009928:Organ Specificity; D010179:Pancreas / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D010195:Pancreatitis / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D019076:Transgenes; D014357:Trypsin / Q000378:metabolism*
D002108:Ceruletide; C489303:PRSS1 protein, human; D014357:Trypsin