title: Novel insights into the global proteome responses of insulin-producing INS-1E cells to different degrees of endoplasmic reticulum stress.
abstract: Exposure of insulin-secreting β-cells to inflammatory cytokines or high concentrations of free fatty acids, factors involved in the pathogenesis of type 1 and type 2 diabetes, leads to endoplasmic reticulum (ER) stress, β-cell dysfunction, and eventually apoptotic β-cell death. The aim of this study was to investigate the impact of ER stress on β-cells at the protein level to evaluate the contribution of post-transcriptional and post-translational changes in ER stress-induced β-cell damage. INS-1E cells were exposed in vitro to the ER-stress inducer cyclopiazonic acid (CPA) at two concentrations, and protein changes were evaluated using 2D-DIGE. CPA, 25 μM, led to massive apoptosis, accompanied by a near complete protein translation shut-down. CPA, 6.25 μM, led to adaptation of the β-cells to ER stress. Identification of the differentially expressed proteins in the two conditions led to the discovery of a clear pattern of defense pathways, with post-translational modifications playing a crucial role. Key alterations included inhibition of insulin translation and post-translational modifications in ER chaperones HYOU1 and HSPA5. Also, a central role for 14-3-3 proteins is suggested. In conclusion, INS-1E cells are highly sensitive to ER stress, leading to important post-transcriptional and post-translational modifications that may contribute to β-cell dysfunction and death.
authors.affiliation: Laboratory for Experimental Medicine and Endocrinology (LEGENDO), University Hospital Gasthuisberg, Catholic University of Leuven, Herestraat 49, Leuven, Belgium.
authors.forename: Wannes
authors.initials: W
authors.lastname: D'Hertog
authors.forename: Michael
authors.initials: M
authors.lastname: Maris
authors.forename: Gabriela B
authors.initials: GB
authors.lastname: Ferreira
authors.forename: Eefje
authors.initials: E
authors.lastname: Verdrengh
authors.forename: Kasper
authors.initials: K
authors.lastname: Lage
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hansen
authors.forename: Alessandra K
authors.initials: AK
authors.lastname: Cardozo
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Workman
authors.forename: Yves
authors.initials: Y
authors.lastname: Moreau
authors.forename: Decio L
authors.initials: DL
authors.lastname: Eizirik
authors.forename: Etienne
authors.initials: E
authors.lastname: Waelkens
authors.forename: Lutgart
authors.initials: L
authors.lastname: Overbergh
authors.forename: Chantal
authors.initials: C
authors.lastname: Mathieu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding / Q000187:drug effects; D020543:Proteome / Q000032:analysis* / Q000235:genetics; D040901:Proteomics / Q000379:methods*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D020543:Proteome; C000543:cyclopiazonic acid