1
|
Chen R, Malagola E, Dietrich M, Zuellig R, Tschopp O, Bombardo M, Saponara E, Reding T, Myers S, Hills AP, Graf R, Sonda S. Akt1 signalling supports acinar proliferation and limits acinar-to-ductal metaplasia formation upon induction of acute pancreatitis. J Pathol 2019; 250:42-54. [PMID: 31531867 DOI: 10.1002/path.5348] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 09/04/2019] [Accepted: 09/12/2019] [Indexed: 12/30/2022]
Abstract
Molecular signalling mediated by the phosphatidylinositol-3-kinase (PI3K)-Akt axis is a key regulator of cellular functions. Importantly, alteration of the PI3K-Akt signalling underlies the development of different human diseases, thus prompting the investigation of the pathway as a molecular target for pharmacologic intervention. In this regard, recent studies showed that small molecule inhibitors of PI3K, the upstream regulator of the pathway, reduced the development of inflammation during acute pancreatitis, a highly debilitating and potentially lethal disease. Here we investigated whether a specific reduction of Akt activity, by using either pharmacologic Akt inhibition, or genetic inactivation of the Akt1 isoform selectively in pancreatic acinar cells, is effective in ameliorating the onset and progression of the disease. We discovered that systemic reduction of Akt activity did not protect the pancreas from initial damage and only transiently delayed leukocyte recruitment. However, reduction of Akt activity decreased acinar proliferation and exacerbated acinar-to-ductal metaplasia (ADM) formation, two critical events in the progression of pancreatitis. These phenotypes were recapitulated upon conditional inactivation of Akt1 in acinar cells, which resulted in reduced expression of 4E-BP1, a multifunctional protein of key importance in cell proliferation and metaplasia formation. Collectively, our results highlight the critical role played by Akt1 during the development of acute pancreatitis in the control of acinar cell proliferation and ADM formation. In addition, these results harbour important translational implications as they raise the concern that inhibitors of PI3K-Akt signalling pathways may negatively affect the regeneration of the pancreas. Finally, this work provides the basis for further investigating the potential of Akt1 activators to boost pancreatic regeneration following inflammatory insults. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Rong Chen
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Ermanno Malagola
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Maren Dietrich
- Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital, Zurich, Switzerland
| | - Richard Zuellig
- Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital, Zurich, Switzerland
| | - Oliver Tschopp
- Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital, Zurich, Switzerland
| | - Marta Bombardo
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Enrica Saponara
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Theresia Reding
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland
| | - Stephen Myers
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Tasmania, Australia
| | - Andrew P Hills
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Tasmania, Australia
| | - Rolf Graf
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland.,Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Sabrina Sonda
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, University Hospital, Zurich, Switzerland.,School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Tasmania, Australia.,Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| |
Collapse
|
2
|
Saunders D, Powers AC. Replicative capacity of β-cells and type 1 diabetes. J Autoimmun 2016; 71:59-68. [PMID: 27133598 DOI: 10.1016/j.jaut.2016.03.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 03/28/2016] [Indexed: 12/16/2022]
Abstract
Efforts to restore β-cell number or mass in type 1 diabetes (T1D) must combine an intervention to stimulate proliferation of remaining β-cells and an intervention to mitigate or control the β-cell-directed autoimmunity. This review highlights features of the β-cell, including it being part of a pancreatic islet, a mini-organ that is highly vascularized and highly innervated, and efforts to promote β-cell proliferation. In addition, the β-cell in T1D exists in a microenvironment with interactions and input from other islet cell types, extracellular matrix, vascular endothelial cells, neuronal projections, and immune cells, all of which likely influence the β-cell's capacity for replication. Physiologic β-cell proliferation occurs in human and rodents in the neonatal period and early in life, after which there is an age-dependent decline in β-cell proliferation, and also as part of the β-cell's compensatory response to the metabolic challenges of pregnancy and insulin resistance. This review reviews the molecular pathways involved in this β-cell proliferation and highlights recent work in two areas: 1) Investigators, using high-throughput screening to discover small molecules that promote human β-cell proliferation, are now focusing on the dual-specificity tyrosine-regulated kinase-1a and cell cycle-dependent kinase inhibitors CDKN2C/p18 or CDKN1A/p21as targets of compounds to stimulate adult human β-cell proliferation. 2) Local inflammation, macrophages, and the local β-cell microenvironment promote β-cell proliferation. Future efforts to harness the responsible mechanisms may lead to new approaches to promote β-cell proliferation in T1D.
Collapse
Affiliation(s)
- Diane Saunders
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, United States; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States; VA Tennessee Valley Healthcare System, Nashville, TN, United States.
| |
Collapse
|