title: Tacrolimus (FK506) attenuates biphasic cytochrome c release and Bad phosphorylation following transient cerebral ischemia in mice.
abstract: Tacrolimus (FK506) has a neuroprotective action on cerebral infarction produced by cerebral ischemia, however, detailed mechanisms underlying this action have not been fully elucidated. We examined temporal profiles of survival-and death-related signals, Bad phosphorylation, release of cytochrome c (cyt.c), activation of caspase 3 and DNA fragmentation in the brain during and after middle cerebral artery occlusion (MCAo) in mice, and then examined the effect of tacrolimus on these signals. C57BL/6J mice were subjected to transient MCAo by intraluminal suture insertion for 60 min. Tacrolimus (1 mg/kg, i.p.) was administered immediately after MCAo. There were biphasic increases in the release of cyt.c in the ischemic core and penumbra; with the first increase toward the end of the occlusion period and the second increase 3-12 h after reperfusion. Tacrolimus significantly inhibited the increase of cytosolic cyt.c during ischemia and reperfusion. Phosphorylated Bad, Ser-136 (P-Bad(136)) and Ser-155 (P-Bad(155)) were detected 30 min after MCAo and after reperfusion in the ischemic cortex, respectively. Tacrolimus increased P-Bad(136) during ischemia and prolonged P-Bad(155) expression after reperfusion. Tacrolimus also decreased caspase-3 and terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling-positive cells, and reduced the size of infarct 24 h after reperfusion. Our study provided the first evidence that the neuroprotective action of tacrolimus involved inhibition of biphasic cyt.c release from mitochondria, possibly via up-regulation of Bad phosphorylation at different sites after focal cerebral ischemia and reperfusion.
authors.affiliation: Pharmacology Research Laboratories, Astellas Pharma Inc., 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Furuichi
authors.forename: N
authors.initials: N
authors.lastname: Matsuoka
authors.forename: S
authors.initials: S
authors.lastname: Mutoh
authors.forename: T
authors.initials: T
authors.lastname: Yanagihara
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D020520:Brain Infarction / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D045304:Cytochromes c / Q000378:metabolism*; D004195:Disease Models, Animal; D007150:Immunohistochemistry / Q000379:methods; D007166:Immunosuppressive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D020287:In Situ Nick-End Labeling; D002546:Ischemic Attack, Transient / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation / Q000187:drug effects; D016559:Tacrolimus / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D051025:bcl-Associated Death Protein / Q000378:metabolism*
chemical_list: C494820:Bad protein, mouse; D007166:Immunosuppressive Agents; D051025:bcl-Associated Death Protein; D045304:Cytochromes c; D016559:Tacrolimus