The unfolded protein response (UPR) maintains balance between protein synthesis and endoplasmic reticulum (ER) protein-folding by inhibiting translation to decrease global protein synthesis, increasing degradation and disposal of unfolded protein intermediates from the ER, and increasing the folding capacity of the ER by expanding its volume and increasing chaperone synthesis. Chronic ER stress leads to a defective UPR and is strongly associated with neurodegenerative diseases, cancers, and metabolic syndrome. Azoramide is a small molecule that has been shown to improve ER protein-folding ability by dose-dependently (1-25 μM) activating reporter genes whose expression is driven by the cellular UPR response element and the ER stress response element. At 1-25 μM, this compound can also stimulate the expression of multiple chaperone proteins to enhance ER chaperone capacity and induce phosphorylation of eukaryotic translation initiation factor 2α subunit (eIF2α) to reduce protein synthesis. At 150 mg/kg, azoramide exerts antidiabetic activity in both ob/ob and diet-induced obese mice, improving insulin sensitivity and glucose homeostasis, as well as protecting pancreatic β cells against ER stress.
1) Fu?(2015), Phenotypic assays identify azoramide as a small-molecule modulator of the unfolded protein response with antidiabetic activity; Sci. Transl. Med., 7?292ra98
