title: Mechanistic study of TRPM2-Ca(2+)-CAMK2-BECN1 signaling in oxidative stress-induced autophagy inhibition.
abstract: Reactive oxygen species (ROS) have been commonly accepted as inducers of autophagy, and autophagy in turn is activated to relieve oxidative stress. Yet, whether and how oxidative stress, generated in various human pathologies, regulates autophagy remains unknown. Here, we mechanistically studied the role of TRPM2 (transient receptor potential cation channel subfamily M member 2)-mediated Ca(2+) influx in oxidative stress-mediated autophagy regulation. On the one hand, we demonstrated that oxidative stress triggered TRPM2-dependent Ca(2+) influx to inhibit the induction of early autophagy, which renders cells more susceptible to death. On the other hand, oxidative stress induced autophagy (and not cell death) in the absence of the TRPM2-mediated Ca(2+) influx. Moreover, in response to oxidative stress, TRPM2-mediated Ca(2+) influx activated CAMK2 (calcium/calmodulin dependent protein kinase II) at levels of both phosphorylation and oxidation, and the activated CAMK2 subsequently phosphorylated BECN1/Beclin 1 on Ser295. Ser295 phosphorylation of BECN1 in turn decreased the association between BECN1 and PIK3C3/VPS34, but induced binding between BECN1 and BCL2. Clinically, acetaminophen (APAP) overdose is the most common cause of acute liver failure worldwide. We demonstrated that APAP overdose also activated ROS-TRPM2-CAMK2-BECN1 signaling to suppress autophagy, thereby causing primary hepatocytes to be more vulnerable to death. Inhibiting the TRPM2-Ca(2+)-CAMK2 cascade significantly mitigated APAP-induced liver injury. In summary, our data clearly demonstrate that oxidative stress activates the TRPM2-Ca(2+)-CAMK2 cascade to phosphorylate BECN1 resulting in autophagy inhibition.
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Guo
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Baixia
authors.initials: B
authors.lastname: Hao
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Xianli
authors.initials: X
authors.lastname: Shi
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Lu
authors.affiliation: b School of Biomedical Sciences, University of Hong Kong , Hong Kong , China.
authors.forename: Connie W M
authors.initials: CW
authors.lastname: Wong
authors.affiliation: c Department of Clinical Oncology , Queen Elizabeth Hospital , Kowloon, Hong Kong , China.
authors.forename: Victor W S
authors.initials: VW
authors.lastname: Ma
authors.affiliation: c Department of Clinical Oncology , Queen Elizabeth Hospital , Kowloon, Hong Kong , China.
authors.forename: Timothy T C
authors.initials: TT
authors.lastname: Yip
authors.affiliation: c Department of Clinical Oncology , Queen Elizabeth Hospital , Kowloon, Hong Kong , China.
authors.forename: Joseph S K
authors.initials: JS
authors.lastname: Au
authors.affiliation: b School of Biomedical Sciences, University of Hong Kong , Hong Kong , China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Hao
authors.affiliation: b School of Biomedical Sciences, University of Hong Kong , Hong Kong , China.
authors.forename: King-Ho
authors.initials: KH
authors.lastname: Cheung
authors.affiliation: b School of Biomedical Sciences, University of Hong Kong , Hong Kong , China.|d GHM Institute of CNS regeneration, Jinan University , Guangzhou , China.
authors.forename: Wutian
authors.initials: W
authors.lastname: Wu
authors.affiliation: e Xiamen Heart Center, Medical School of Xiamen University , Xiamen , China.
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Li
authors.affiliation: a Department of Biomedical Sciences , City University of Hong Kong , Hong Kong , China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Yue
mesh_terms: D000082:Acetaminophen / Q000737:chemistry; D000818:Animals; D001343:Autophagy; D000071186:Beclin-1 / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D045744:Cell Line, Tumor; D062787:Drug Overdose; D057809:HEK293 Cells; D006367:HeLa Cells; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016296:Mutagenesis; D018384:Oxidative Stress; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D050053:TRPM Cation Channels / Q000378:metabolism*
chemical_list: C491997:BECN1 protein, human; D000071186:Beclin-1; C115010:Becn1 protein, mouse; D017382:Reactive Oxygen Species; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; C544443:TRPM2 protein, mouse; D000082:Acetaminophen; D012694:Serine; C517657:CAMK2A protein, human; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; C517671:Camk2a protein, mouse; D002118:Calcium
keywords: BECN1; CAMK2; Ca2+; TRPM2; acetaminophen; autophagy; oxidative stress; reactive oxygen species