title: 2-methoxyestradiol attenuates autophagy activation after global ischemia.
abstract: BACKGROUND
  Hypoxia inducible factor 1 (HIF-1) is a key transcriptional factor activated during cerebral ischemia, which regulates a great number of downstream genes, including those associated with cell death. In the present study, we aimed to test the hypothesis that post-ischemic HIF-1α up-regulation might promote autophagy activation; thereby, HIF-1α inhibitor 2ME2 might prevent neurons from ischemic injury through inhibiting autophagy.
  
  
  METHODS
  Global ischemia was induced using the four-vessel occlusion model (4-VO) in Sprague-Dawley rats (male, 250-280g). 2-Methoxyestradiol (2ME2, 5mg/kg, i.p.) was administrated to down-regulate HIF-1α expression. Post-ischemic beclin-1 and LC3 protein expression was determined at different time points through Western blot assay. Neuronal injury was determined by cresyl violet staining and TUNEL staining in coronal histological sections.
  
  
  RESULTS
  The expression of beclin-1 and the ratio of LC3-II/LC3-I increased significantly at 12 and 24 h after ischemia. 2ME2 could remarkably inhibit the up-regulation of beclin-1 and the increase of LC3-II/LC3-I ratio during reperfusion. Moreover, 2ME2 and 3-MA exhibited powerful protective effects against ischemic/reperfusion induced neuronal injury.
  
  
  CONCLUSIONS
  This study confirmed that autophagy participated in post-ischemic neuronal injury. 2ME2, a HIF-1α inhibitor, might significantly decrease autophagy activation after cerebral ischemia and relieve post-ischemic neuronal injury. Our findings demonstrate that autophagy could be a potential target for neuronal protection after cerebral ischemia.
authors.affiliation: Department of Neurology and Institute of Neurology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Xin
authors.forename: Jing
authors.initials: J
authors.lastname: Pan
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Wang
authors.forename: Jian-Fang
authors.initials: JF
authors.lastname: Ma
authors.forename: Jian-Qing
authors.initials: JQ
authors.lastname: Ding
authors.forename: Guo-Yuan
authors.initials: GY
authors.lastname: Yang
authors.forename: Sheng-Di
authors.initials: SD
authors.lastname: Chen
mesh_terms: D000077584:2-Methoxyestradiol; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D002545:Brain Ischemia / Q000188:drug therapy / Q000503:physiopathology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D050257:Tubulin Modulators / Q000008:administration & dosage*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000077584:2-Methoxyestradiol; D000225:Adenine; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D004958:Estradiol; D051793:Hypoxia-Inducible Factor 1; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D050257:Tubulin Modulators; D016159:Tumor Suppressor Protein p53; C505650:BNIP3 protein, rat; C512829:Becn1 protein, rat; C526109:Anxa3 protein, rat; C025946:3-methyladenine