Titre
Sustained production of spliced X-box binding protein 1 (XBP1) induces pancreatic beta cell dysfunction and apoptosis.
Type
article
Institution
Externe
Périodique
Auteur(s)
Allagnat, F.
Auteure/Auteur
Christulia, F.
Auteure/Auteur
Ortis, F.
Auteure/Auteur
Pirot, P.
Auteure/Auteur
Lortz, S.
Auteure/Auteur
Lenzen, S.
Auteure/Auteur
Eizirik, D.L.
Auteure/Auteur
Cardozo, A.K.
Auteure/Auteur
Liens vers les personnes
ISSN
1432-0428
Statut éditorial
Publié
Date de publication
2010-06
Volume
53
Numéro
6
Première page
1120
Dernière page/numéro d’article
1130
Peer-reviewed
Oui
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Publication Status: ppublish
Résumé
Pro-inflammatory cytokines involved in the pathogenesis of type 1 diabetes deplete endoplasmic reticulum (ER) Ca2+ stores, leading to ER-stress and beta cell apoptosis. However, the cytokine-induced ER-stress response in beta cells is atypical and characterised by induction of the pro-apoptotic PKR-like ER kinase (PERK)-C/EBP homologous protein (CHOP) branch of the unfolded protein response, but defective X-box binding protein 1 (XBP1) splicing and activating transcription factor 6 activation. The purpose of this study was to overexpress spliced/active Xbp1 (XBP1s) to increase beta cell resistance to cytokine-induced ER-stress and apoptosis.
Xbp1s was overexpressed using adenoviruses and knocked down using small interference RNA in rat islet cells. In selected experiments, Xbp1 was also knocked down in FACS-purified rat beta cells and rat fibroblasts. Expression and production of XBP1s and key downstream genes and proteins was measured and beta cell function and viability were evaluated.
Adenoviral-mediated overproduction of Xbp1s resulted in increased XBP1 activity and induction of several XBP1s target genes. Surprisingly, XBP1s overexpression impaired glucose-stimulated insulin secretion and increased beta cell apoptosis, whereas it protected fibroblasts against cell death induced by ER-stress. mRNA expression of Pdx1 and Mafa was inhibited in cells overproducing XBP1s, leading to decreased insulin expression. XBP1s knockdown partially restored cytokine/ER-stress-driven insulin and Pdx1 inhibition but had no effect on cytokine-induced ER-stress and apoptosis.
XBP1 has a distinct inhibitory role in beta cell as compared with other cell types. Prolonged XBP1s production hampers beta cell function via inhibition of insulin, Pdx1 and Mafa expression, eventually leading to beta cell apoptosis.
Xbp1s was overexpressed using adenoviruses and knocked down using small interference RNA in rat islet cells. In selected experiments, Xbp1 was also knocked down in FACS-purified rat beta cells and rat fibroblasts. Expression and production of XBP1s and key downstream genes and proteins was measured and beta cell function and viability were evaluated.
Adenoviral-mediated overproduction of Xbp1s resulted in increased XBP1 activity and induction of several XBP1s target genes. Surprisingly, XBP1s overexpression impaired glucose-stimulated insulin secretion and increased beta cell apoptosis, whereas it protected fibroblasts against cell death induced by ER-stress. mRNA expression of Pdx1 and Mafa was inhibited in cells overproducing XBP1s, leading to decreased insulin expression. XBP1s knockdown partially restored cytokine/ER-stress-driven insulin and Pdx1 inhibition but had no effect on cytokine-induced ER-stress and apoptosis.
XBP1 has a distinct inhibitory role in beta cell as compared with other cell types. Prolonged XBP1s production hampers beta cell function via inhibition of insulin, Pdx1 and Mafa expression, eventually leading to beta cell apoptosis.
Sujets
PID Serval
serval:BIB_1FB486CBB448
PMID
Open Access
Oui
Date de création
2019-05-10T08:34:57.537Z
Date de création dans IRIS
2025-05-20T17:24:45Z