Inhibition of double-stranded RNA-dependent protein kinase prevents oxytosis and ferroptosis in mouse hippocampal HT22 cells. (15th April 2019)

• Record Type: Journal Article
• Authors: Hirata, Yoko; Iwasaki, Takuya; Makimura, Yukimi; Okajima, Sayaka; Oh-hashi, Kentaro; Takemori, Hiroshi
• Is Part Of: Toxicology. Volume 418(2019)
• Page Start: 1
• Page End: 10
• Publication Date: 2019-04-15
• Subjects: ATF4 activating transcription factor 4 -- ATF6 activating transcription factor 6 -- Chac1 Cation transport regulator homologue 1 -- 2-DG 2-deoxyglucose -- ECAR extracellular acidification rate -- ER endoplasmic reticulum -- ERK extracellular signal-regulated kinase -- DMEM Dulbecco's modified Eagle's medium -- GADD153 growth arrest- and DNA damage-inducible gene 153 -- GAPDH glyceraldehyde 3 phosphate dehydrogenase -- Grp78 78-kDa glucose-regulated protein -- GSH glutathione -- HO-1 heme oxygenase-1 -- IRE1 inositol-requiring enzyme 1 -- JNK c-Jun NH2-terminal kinase -- KO knockout -- LDH lactate dehydrogenase -- MAPK mitogen-activated protein kinase -- NAC N-acetyl cysteine -- OCR oxygen consumption rate -- PERK protein kinase RNA-like ER kinase -- PKR double-stranded RNA dependent protein kinase -- RT-PCR reverse transcription-polymerase chain reaction -- UPR unfolded protein response -- XBP1 X-box binding protein 1; Ferroptosis -- IRE1 -- JNK -- Oxytosis -- PKR; Toxicology -- Periodicals; Chemicals -- Physiological effect -- Periodicals; 615.9005
• DOI: 10.1016/j.tox.2019.02.012
• Languages: English
• ISSNs: 0300-483X

Abstract

Highlights: Pharmacological inhibition of PKR alleviate ferroptosis and oxytosis in HT22 cells. The specific PKR inhibitor C16 prevents erastin-induced activation of IRE-JNK pathway. C16 activates the ERK pathway and increases in ATP levels. Abstract: Double-stranded RNA-dependent protein kinase (PKR) is a component of signal transduction pathways mediating various stress signals including oxidative stress and endoplasmic reticulum (ER) stress and is suggested to be implicated in several neurodegenerative diseases. Cell death in neurodegenerative conditions has been linked to oxidative stress; however, the involvement of PKR in endogenous oxidative stress such as oxytosis and ferroptosis which is quite distinct from classical apoptosis remains unknown. We investigated here the effect of a PKR inhibitor C16 (an imidazole-oxindole derivative) on oxytosis and ferroptosis in cultured HT22 mouse hippocampal cells. C16 prevented glutamate- and erastin-induced cell death, reactive oxygen species accumulation, Ca 2+ influx, phosphorylation of inositol-requiring enzyme 1 (IRE1), one of the three branches of ER stress signaling and its downstream signaling components. On the other hand, C16 did not prevent oxidative stress-induced heme oxygenase-1 expression; instead, C16 activated the extracellular signal-regulated kinase pathway. The protective effect of C16 is diminished in PKR knockout HT22 cells. Real time measurements of the oxygen consumption rate and extracellular acidification rate over a long period of time leading to cell death showed that C16 partially prevented erastin-induced mitochondrial and glycolytic dysfunction. These results suggest that PKR is an important component of oxytosis and ferroptosis and the inhibition of PKR is neuroprotective against endogenous oxidative stress-induced cell death and provide an effective strategy for neuroprotection.