title: Increased nuclear apoptosis-inducing factor after transient focal ischemia: a 12/15-lipoxygenase-dependent organelle damage pathway.
abstract: 12/15-lipoxygenase (12/15-LOX) contributes to acute neuronal injury and edema formation in mouse models of middle cerebral artery occlusion (MCAO). The apoptosis-inducing factor (AIF) is implicated in caspase-independent forms of apoptosis, and has been linked to ischemic neuronal cell death. We show here that increased AIF in the peri-ischemic cortex of mouse colocalizes with 12/15-LOX after 2 h of MCAO. The 12/15-LOX inhibitor baicalein prevents the increase and nuclear localization of AIF, suggesting this pathway may be partially responsible for the neuroprotective qualities of baicalein. Using an established cell line model of neuronal oxidative stress, we show that 12/15-LOX activated after glutathione depletion leads to AIF translocation to the nucleus, which is abrogated by the 12/15-LOX inhibitor baicalein (control: 19.3%+/-6.8% versus Glutamate: 64.0%+/-8.2% versus glutamate plus baicalein: 11.4%+/-2.2%). Concomitantly, resident proteins of the ER are dispersed throughout the cell (control: 31.0%+/-8.4% versus glutamate: 70.0%+/-5.5% versus glutamate plus baicalein: 8.0%+/-2.7%), suggesting cell death through organelle damage. Taken together, these findings show that 12/15-LOX and AIF are sequential actors in a common cell death pathway that may contribute to stroke-induced brain damage.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Pallast
authors.forename: Ken
authors.initials: K
authors.lastname: Arai
authors.forename: Anton
authors.initials: A
authors.lastname: Pekcec
authors.forename: Kazim
authors.initials: K
authors.lastname: Yigitkanli
authors.forename: Zhanyang
authors.initials: Z
authors.lastname: Yu
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.forename: Eng H
authors.initials: EH
authors.lastname: Lo
authors.forename: Klaus
authors.initials: K
authors.lastname: van Leyen
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000235:genetics / Q000378:metabolism*; D001929:Brain Edema / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044950:Flavanones / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D008084:Lipoxygenase / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000201:enzymology / Q000473:pathology
chemical_list: D051033:Apoptosis Inducing Factor; D004791:Enzyme Inhibitors; D044950:Flavanones; C494830:AIFM1 protein, mouse; C006680:baicalein; D008084:Lipoxygenase