Hydrogen peroxide induces Beclin 1-independent autophagic cell death by suppressing the mTOR pathway via promoting the ubiquitination and degradation of Rheb in GSH-depleted RAW 264.7 cells.
A novel mechanism for H₂O₂-induced autophagic cell death in GSH-depleted RAW 264.7 cells, a murine macrophage cell line, is proposed. Under GSH-depleted conditions, H₂O₂-induced autophagic cell, characterized by an increased LC3-II/I ratio, a decreased level of p62 and the formation of autophagic vacuoles, was inhibited by bafilomycin A1 and by Atg5 siRNA transfection, whereas the cell death was not inhibited by zVAD-fmk, by PI3K inhibitors or by Beclin 1 siRNA transfection. In addition, H₂O₂ treatment reduced the activity of mTOR and promoted the ubiquitination and degradation of Rheb, a key upstream activator of mTOR. Furthermore, proteasome inhibition with MG132 restored the expression of Rheb and increased mTOR activity, resulting in an increased viability of H₂O₂-treated cells. Collectively, these findings demonstrate that H₂O₂ induces Beclin 1-independent autophagic cell death by suppressing the mTOR pathway via promoting the ubiquitination and degradation of Rheb in GSH-depleted RAW 264.7 cells.
Institute of Hansen's Disease, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul 137-701, Korea.
Gimoon
G
Seo
Seong Keun
SK
Kim
Yu Jeong
YJ
Byun
Eunhye
E
Oh
Seong-Whan
SW
Jeong
Gue Tae
GT
Chae
Seong-Beom
SB
Lee
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D000071187:Autophagy-Related Protein 5; D000071186:Beclin-1; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D005978:Glutathione / Q000172:deficiency*; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D008247:Lysosomes / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D000076205:Ras Homolog Enriched in Brain Protein; D015398:Signal Transduction / Q000187:drug effects*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000378:metabolism; D054875:Ubiquitination / Q000187:drug effects
D000590:Amino Acid Chloromethyl Ketones; D051017:Apoptosis Regulatory Proteins; C495773:Atg5 protein, mouse; D000071187:Autophagy-Related Protein 5; D000071186:Beclin-1; C115010:Becn1 protein, mouse; D004791:Enzyme Inhibitors; C490981:Gtf2h1 protein, mouse; D018942:Macrolides; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D034741:RNA, Small Interfering; D000076205:Ras Homolog Enriched in Brain Protein; C490213:Rheb protein, mouse; D014157:Transcription Factors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D051758:Transcription Factor TFIIH; C040929:bafilomycin A1; D006861:Hydrogen Peroxide; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D046988:Proteasome Endopeptidase Complex; D020559:Monomeric GTP-Binding Proteins; D005978:Glutathione