title: Effect of endoplasmic reticulum (ER) stress inducer thapsigargin on the expression of extracellular-superoxide dismutase in mouse 3T3-L1 adipocytes.
abstract: Endoplasmic reticulum stress is related to metabolic disorders, including atherosclerosis and type 2 diabetes. It is known that inflammatory adipocytokines and oxidative stress are increased, while anti-inflammatory adipocytokines such as adiponectin are decreased in adipocytes during above conditions. Extracellular-superoxide dismutase is an anti-inflammatory enzyme that protects cells from oxidative stress. Because plasma extracellular-superoxide dismutase levels in type 2 diabetes patients were inversely related to the body mass index and homeostasis model assessment-insulin resistance index, it is speculated that the regulation of extracellular-superoxide dismutase might lead to the suppression of metabolic disorders. Here, we observed the reduction of extracellular-superoxide dismutase and adiponectin in 3T3-L1 adipocytes treated with thapsigargin, an endoplasmic reticulum stress inducer. Interestingly, tunicamycin, another endoplasmic reticulum stress inducer, did not decrease the expression of extracellular-superoxide dismutase in spite of the induction of glucose regulated protein kinase 78 kDa, an endoplasmic reticulum stress marker. Moreover, eukaryotic translation initiation factor 2α signaling cascade plays a pivotal role in the reduction of extracellular-superoxide dismutase in 3T3-L1 adipocytes during endoplasmic reticulum stress conditions.
authors.affiliation: Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kamiya
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Hara
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Adachi
keywords: endoplasmic reticulum stress; eukaryotic translation initiation factor 2α; extracellular-superoxide dismutase; obesity; reactive oxygen species