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Local in vivo GSK3? knockdown promotes pancreatic ? cell and acinar cell regeneration in 90% pancreatectomized rat.

ABSTRACT: Endocrine and exocrine insufficiencies are associated with serious diseases such as diabetes and pancreatitis, respectively. Pancreatic cells retain the capacity to regenerate in the context of cell deficiency. The remnant pancreas after pancreatectomy (Px) is a valuable target for testing the efficiency of pharmacological interventions to stimulate cell regeneration. Here, we tested the ability of GSK3? downregulation on the stimulation of ?- and acinar cell regeneration after 90% Px in adult rats. We developed an in vivo approach based on local silencing of GSK3?, by delivering antisense morpholino-oligonucleotides within the remnant pancreas of 90% pancreatectomized rats, and evaluated its impact on the regenerative potential of pancreatic ? and exocrine cells. ?-Cell (BC) mass was evaluated by morphometry. Cell proliferation and apoptosis were assessed by 5'bromo 2'deoxyuridine (BrdU) incorporation method and TUNEL assay, respectively. The expression of Sox9, Neurogenin-3 (Ngn3), and PDX1 was evaluated by immunohistochemistry. We show that intrapancreatic GSK3? knockdown leads to increased BC mass (BCM) in 90% pancreatectomized rats by promoting both BC proliferation and differentiation. Moreover, downregulation of GSK3? significantly improves exocrine growth and prevents acinar cell apoptosis in vivo. Our study designates GSK3? as a viable drug target for therapeutic intervention on diseases of endocrine and exocrine pancreas associated with cell deficiency.

SUBMITTER: Figeac F

PROVIDER: S-EPMC3464647 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

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Local in vivo GSK3β knockdown promotes pancreatic β cell and acinar cell regeneration in 90% pancreatectomized rat.

Figeac Florence F Ilias Anissa A Bailbe Danielle D Portha Bernard B Movassat Jamileh J

Molecular therapy : the journal of the American Society of Gene Therapy 20120724 10

Endocrine and exocrine insufficiencies are associated with serious diseases such as diabetes and pancreatitis, respectively. Pancreatic cells retain the capacity to regenerate in the context of cell deficiency. The remnant pancreas after pancreatectomy (Px) is a valuable target for testing the efficiency of pharmacological interventions to stimulate cell regeneration. Here, we tested the ability of GSK3β downregulation on the stimulation of β- and acinar cell regeneration after 90% Px in adult r ...[more]

PMID: 22828498

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Project description:Aims/hypothesisIndividuals with longstanding and recent-onset type 1 diabetes have a smaller pancreas. Since beta cells represent a very small portion of the pancreas, the loss of pancreas volume in diabetes is primarily due to the loss of pancreatic exocrine mass. However, the structural changes in the exocrine pancreas in diabetes are not well understood.MethodsTo characterise the pancreatic endocrine and exocrine compartments in diabetes, we studied pancreases from adult donors with type 1 diabetes compared with similarly aged donors without diabetes. Islet cell mass, islet morphometry, exocrine mass, acinar cell size and number and pancreas fibrosis were assessed by immunohistochemical staining. To better understand possible mechanisms of altered pancreas size, we measured pancreas size in three mouse models of insulin deficiency.ResultsPancreases from donors with type 1 diabetes were approximately 45% smaller than those from donors without diabetes (47.4 ± 2.6 vs 85.7 ± 3.7 g), independent of diabetes duration or age of onset. Diabetic donor pancreases had decreased beta cell mass (0.061 ± 0.025 vs 0.94 ± 0.21 g) and reduced total exocrine mass (42.0 ± 4.9 vs 96.1 ± 6.5 g). Diabetic acinar cells were similar in size but fewer in number compared with those in pancreases from non-diabetic donors (63.7 ± 8.1 × 109 vs 121.6 ± 12.2 × 109 cells/pancreas), likely accounting for the difference in pancreas size. Within the type 1 diabetes exocrine tissue, there was a greater degree of fibrosis. The pancreases in three mouse models of insulin deficiency were similar in size to those in control mice.Conclusions/interpretationPancreases from donors with type 1 diabetes are smaller than normal donor pancreases because exocrine cells are fewer in number rather than smaller in size; these changes occur early in the disease process. Our mouse data suggest that decreased pancreas size in type 1 diabetes is not directly caused by insulin deficiency, but the precise mechanism responsible remains unclear.

Project description:Pancreatic insufficiency (PI) when left untreated results in a state of malnutrition due to an inability to absorb nutrients. Frequently, PI is diagnosed as part of a larger clinical presentation in cystic fibrosis or Shwachman-Diamond syndrome. In this study, a mouse model for isolated exocrine PI was identified in a mouse line generated by a transgene insertion. The trait is inherited in an autosomal recessive pattern, and homozygous animals are growth retarded, have abnormal immunity, and have reduced life span. Mice with the disease locus, named pequeño (pq), exhibit progressive apoptosis of pancreatic acinar cells with severe exocrine acinar cell loss by 8 wk of age, while the islets and ductal tissue persist. The mutation in pq/pq mice results from a random transgene insertion. Molecular characterization of the transgene insertion site by fluorescent in situ hybridization and genomic deletion mapping identified an approximately 210-kb deletion on Chromosome 3, deleting two genes. One of these genes, Serpini2, encodes a protein that is a member of the serpin family of protease inhibitors. Reintroduction of only the Serpini2 gene by bacterial artificial chromosome transgenic complementation corrected the acinar cell defect as well as body weight and immune phenotypes, showing that deletion of Serpini2 causes the pequeño phenotype. Dietary supplementation of pancreatic enzymes also corrected body size, body weight, and immunodeficiency, and increased the life span of Serpini2-deficient mice, despite continued acinar cell loss. To our knowledge, this study describes the first characterized genetic animal model for isolated PI. Genetic complementation of the transgene insertion mutant demonstrates that Serpini2 deficiency directly results in the acinar cell apoptosis, malabsorption, and malnutrition observed in pq/pq mice. The rescue of growth retardation, immunodeficiency, and mortality by either Serpini2 bacterial artificial chromosome transgenic expression or by pancreatic enzyme supplementation demonstrates that these phenotypes are secondary to malnutrition in pq/pq mice.

Project description:Maintenance of the pancreatic acinar cell phenotype suppresses tumor formation. Hence, repetitive acute or chronic pancreatitis, stress conditions in which the acinar cells dedifferentiate, predispose for cancer formation in the pancreas. Dedifferentiated acinar cells acquire a large panel of duct cell-specific markers. However, it remains unclear to what extent dedifferentiated acini differ from native duct cells and which genes are uniquely regulating acinar cell dedifferentiation. Moreover, most studies have been performed on mice since the availability of human cells is scarce. Here, we applied a non-genetic lineage tracing method of human pancreatic exocrine acinar and duct cells that allowed cell-type-specific gene expression profiling by RNA sequencing. Subsequent to this discovery analysis, one transcription factor that was unique for dedifferentiated acinar cells was functionally characterized. RNA sequencing analysis showed that human dedifferentiated acinar cells expressed genes in "Pathways of cancer" with a prominence of MECOM (EVI-1), a transcription factor that was not expressed by duct cells. During mouse embryonic development, pre-acinar cells also transiently expressed MECOM and in the adult mouse pancreas, MECOM was re-expressed when mice were subjected to acute and chronic pancreatitis, conditions in which acinar cells dedifferentiate. In human cells and in mice, MECOM expression correlated with and was directly regulated by SOX9. Mouse acinar cells that, by genetic manipulation, lose the ability to upregulate MECOM showed impaired cell adhesion, more prominent acinar cell death, and suppressed acinar cell dedifferentiation by limited ERK signaling. In conclusion, we transcriptionally profiled the two major human pancreatic exocrine cell types, acinar and duct cells, during experimental stress conditions. We provide insights that in dedifferentiated acinar cells, cancer pathways are upregulated in which MECOM is a critical regulator that suppresses acinar cell death by permitting cellular dedifferentiation.

Dataset Information

Local in vivo GSK3? knockdown promotes pancreatic ? cell and acinar cell regeneration in 90% pancreatectomized rat.

Publications

Local in vivo GSK3β knockdown promotes pancreatic β cell and acinar cell regeneration in 90% pancreatectomized rat.

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