Novel insights into the global proteome responses of insulin-producing INS-1E cells to different degrees of endoplasmic reticulum stress.
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.
D'Hertog
Wannes
W
Laboratory for Experimental Medicine and Endocrinology (LEGENDO), University Hospital Gasthuisberg, Catholic University of Leuven, Herestraat 49, Leuven, Belgium.
Maris
Michael
M
Ferreira
Gabriela B
GB
Verdrengh
Eefje
E
Lage
Kasper
K
Hansen
Daniel A
DA
Cardozo
Alessandra K
AK
Workman
Christopher T
CT
Moreau
Yves
Y
Eizirik
Decio L
DL
Waelkens
Etienne
E
Overbergh
Lutgart
L
Mathieu
Chantal
C
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
D004791:Enzyme Inhibitors; D007211:Indoles; D020543:Proteome; C000543:cyclopiazonic acid