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Comparative detection method of early onset cytokine‐induced stress in β‐cells (INS‐1E)
Author(s) -
Beukes Natasha,
Levendal RubyAnn,
Prinsloo Earl,
Frost Carminita
Publication year - 2019
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1729
Subject(s) - unfolded protein response , endoplasmic reticulum , viability assay , mtt assay , downregulation and upregulation , thioflavin , chemistry , blot , glucose regulated protein , cell , microbiology and biotechnology , biology , medicine , biochemistry , disease , alzheimer's disease , gene
β‐Cells contain a prominent endoplasmic reticulum (ER), disrupting ER homeostasis and function, activating the unfolded protein response (UPR). Currently, no direct protocols measure the UPR initiation. Current methods to measure ER stress include the quantification of nitric oxide (NO) (indirect method), Western blotting, and qRT‐PCR of downstream components. However, these methods do not account for the overlap with mitochondrial dysfunction. In this study, INS‐1E cells were exposed to proinflammatory cytokines to induce ER stress, as determined using NO, thioflavin T (ThT) binding, and β‐cell functionality (insulin production). ER stress was confirmed through the upregulation of CHOP. Cell viability was monitored using MTT, sulforhodamine B, and the xCELLigence system. Morphological changes were monitored using electron microscopy. IL‐1β exposure‐induced β‐cell stress after 4 H, decreased insulin levels, and increased thioflavin binding were noted. Increased NO production was only detected after 10 H, highlighting its lack of sensitivity, and the need for a continuous, selective, rapid, convenient, and economical detection method for early onset of ER stress. Standard methods (MTT and NO) failed to detect early ER stress. The xCELLigence coupled with a functional assay such as the detection of insulin levels or ThT are better predictors of ER stress in INS‐1E cells.