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Title: Pancreas-specific Sirt1-deficiency in mice compromises beta-cell function without development of hyperglycemia      
dateReleased:
03-01-2016
description:
Sirtuin 1 (Sirt1) has been reported to be a critical positive regulator of glucose-stimulated insulin secretion in pancreatic beta-cells. The effects on islet cells and blood glucose levels when Sirt1 is deleted specifically in the pancreas are still unclear.This study examined islet glucose responsiveness, blood glucose levels, pancreatic islet histology and gene expression in Pdx1-Cre;Sirt1(ex4F/F) mice that have loss of function and loss of expression of Sirt1 specifically in the pancreas. We found that in the Pdx1-Cre;Sirt1(ex4F/F) mice, the relative insulin positive area and the islet size distribution were unchanged. However, beta-cells were functionally impaired, presenting with lower glucose-stimulated insulin secretion. This defect was not due to a reduced expression of insulin but was associated with a decreased expression of the glucose transporter Slc2A2/Glut2 and of the Glucagon like peptide-1 receptor (Glp1r) as well as with a marked down regulation of endoplasmic reticulum (ER) chaperones that participate in the Unfolded Protein Response (UPR) pathway. Counter intuitively, the Sirt1-deficient mice did not develop hyperglycemia. Pancreatic polypeptide (PP) cells were the only other islet cells affected, with reduced numbers in the Sirt1-deficient pancreas. This study provides new mechanistic insights showing that beta-cell function in Sirt1-deficient pancreas is affected due to altered glucose sensing and deregulation of the UPR pathway. Interestingly, we uncover a context in which impaired beta-cell function is not accompanied by increased glycemia. This points to a unique compensatory mechanism. Given the reduction in PP, investigation of its role in the control of blood glucose is warranted. To uncover other Sirt1-regulated mechanisms, we performed a gene expression microarray analysis comparing pancreata from the 6 month old Sirt1–deficient mice to their controls (n=3 per group).
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-67239
refinement:
raw
alternateIdentifiers:
67239
keywords:
functional genomics
dateModified:
03-06-2016
availability:
available
types:
gene expression
name:
Mus musculus
ID:
A-GEOD-16570
name:
[MoGene-2_0-st] Affymetrix Mouse Gene 2.0 ST Array [transcript (gene) version]
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-67239/E-GEOD-67239.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-67239/E-GEOD-67239.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE67239
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress

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