O. Methoxyflavones protect cells against endoplasmic reticulum stress and neurotoxin. Enhanced endoplasmic reticulum (ER) stress leads to cell death in various pathophysiological situations. During a search for compounds that regulate ER stress, we identified methoxyflavones, a group of flavonoids, as strong protective agents against ER stress. Analysis in mouse insulinoma MIN6 cells revealed that methoxyflavones mildly activated the eukaryotic initiation factor 2␣ and nuclear factor erythroid 2-related factor pathways, but not the XBP1 pathway, and induced downstream genes, including glucose-regulated protein (GRP) 78, a molecular chaperone in the ER. The protective effect of methoxyflavones was enhanced by agents that increase intracellular cAMP levels such as forskolin, dibutyryl-cAMP and IBMX, but suppressed by the protein kinase A (PKA) inhibitor H-89, suggesting involvement of the PKA pathway in the regulation of ER stress by methoxyflavones. Consistent with the results in cultured cells, pretreatment of mice with tangeretin, a methoxyflavone, enhanced expression of GRP78 and HO-1 without causing ER stress in renal tubular epithelium and prevented tunicamycin-induced cell death. Furthermore, preadministration of tangeretin in mice enhanced expression of GRP78 in the substantia nigra pars compacta and protected dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a neurotoxin that induces both oxidative and ER stress. These results suggest that methoxyflavones play an important role in the regulation of ER stress and could be a therapeutic target for the ER stress-related diseases.

O. A dibenzoylmethane derivative protects dopaminergic neurons against both oxidative stress and endoplasmic reticulum stress.

No abstract

Abstract. Enhanced levels of intracellular stresses such as oxidative stress and endoplasmic reticulum (ER) stress are implicated in various neuropathological conditions including brain ischemia and neurodegeneration. During a search for compounds that regulate ER stress and ER stress-induced cell death, we identified a carbazole derivative 16-14 [9-(3-cyanobenzyl)-1,4-dimethylcarbazole] that protected against both ER stress and glutathione depletion. 16-14 suppressed tunicamycin (Tm)-induced cell death in both F9 Herp KO cells and PC12 cells, and its regulation of ER stress was associated with reduced levels of unfolded protein response (UPR) signaling. ER stress caused by overexpression of a fluorescent ER-resident protein, GFP-KDEL, was also attenuated by 16-14 without altering the expression levels of GFP-KDEL. 16-14 also prevented glutathione depletion-induced cell death caused by buthionine sulfoximine (BSO), but not likely via its anti-oxidative activity. Further analysis revealed that 16-14 suppressed increases in intracellular Ca 2+ in response to thapsigargin (Tg). These results suggest that 16-14 may protect cells against different stresses via the maintenance of intracellular Ca 2+ homeostasis. [ Supplementary Fig. 1: available only at http://dx.doi.org / 10.1254 / jphs.08136FP]

It was concluded that Cry-consensus peptide effectively controlled allergic responses, which results from shifting from a Th2-dominated to a Th1-dominated immune response.