title: Epoxyeicosatrienoic acids protect cardiac cells during starvation by modulating an autophagic response.
abstract: Epoxyeicosatrienoic acids (EETs) are cytochrome P450 epoxygenase metabolites of arachidonic acid involved in regulating pathways promoting cellular protection. We have previously shown that EETs trigger a protective response limiting mitochondrial dysfunction and reducing cellular death. Considering it is unknown how EETs regulate cell death processes, the major focus of the current study was to investigate their role in the autophagic response of HL-1 cells and neonatal cardiomyocytes (NCMs) during starvation. We employed a dual-acting synthetic analog UA-8 (13-(3-propylureido)tridec-8-enoic acid), possessing both EET-mimetic and soluble epoxide hydrolase (sEH) inhibitory properties, or 14,15-EET as model EET molecules. We demonstrated that EETs significantly improved viability and recovery of starved cardiac cells, whereas they lowered cellular stress responses such as caspase-3 and proteasome activities. Furthermore, treatment with EETs resulted in preservation of mitochondrial functional activity in starved cells. The protective effects of EETs were abolished by autophagy-related gene 7 (Atg7) short hairpin RNA (shRNA) or pharmacological inhibition of autophagy. Mechanistic evidence demonstrated that sarcolemmal ATP-sensitive potassium channels (pmKATP) and enhanced activation of AMP-activated protein kinase (AMPK) played a crucial role in the EET-mediated effect. Our data suggest that the protective effects of EETs involve regulating the autophagic response, which results in a healthier pool of mitochondria in the starved cardiac cells, thereby representing a novel mechanism of promoting survival of cardiac cells. Thus, we provide new evidence highlighting a central role of the autophagic response in linking EETs with promoting cell survival during deep metabolic stress such as starvation.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: V
authors.initials: V
authors.lastname: Samokhvalov
authors.forename: N
authors.initials: N
authors.lastname: Alsaleh
authors.forename: H E
authors.initials: HE
authors.lastname: El-Sikhry
authors.forename: K L
authors.initials: KL
authors.lastname: Jamieson
authors.forename: C B
authors.initials: CB
authors.lastname: Chen
authors.forename: D G
authors.initials: DG
authors.lastname: Lopaschuk
authors.forename: C
authors.initials: C
authors.lastname: Carter
authors.forename: P E
authors.initials: PE
authors.lastname: Light
authors.forename: R
authors.initials: R
authors.lastname: Manne
authors.forename: J R
authors.initials: JR
authors.lastname: Falck
authors.forename: J M
authors.initials: JM
authors.lastname: Seubert
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000596:Amino Acids / Q000172:deficiency*; D000818:Animals; D000831:Animals, Newborn; D001343:Autophagy / Q000187:drug effects*; D001549:Benzamides / Q000494:pharmacology; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D009829:Oleic Acids / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D015221:Potassium Channels / Q000378:metabolism; D051381:Rats; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: C558111:(13-(3-propylureido)tridec-8-enoic acid); D000596:Amino Acids; D001549:Benzamides; D002316:Cardiotonic Agents; D009829:Oleic Acids; D015221:Potassium Channels; C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D000255:Adenosine Triphosphate; C410297:HMR 1098; D055372:AMP-Activated Protein Kinases; D015126:8,11,14-Eicosatrienoic Acid