title: Calreticulin Binds to Fas Ligand and Inhibits Neuronal Cell Apoptosis Induced by Ischemia-Reperfusion Injury.
abstract: BACKGROUND
  Calreticulin (CRT) can bind to Fas ligand (FasL) and inhibit Fas/FasL-mediated apoptosis of Jurkat T cells. However, its effect on neuronal cell apoptosis has not been investigated.
  
  
  OBJECTIVE
  We aimed to evaluate the neuroprotective effect of CRT following ischemia-reperfusion injury (IRI).
  
  
  METHODS
  Mice underwent middle cerebral artery occlusion (MCAO) and SH-SY5Y cells subjected to oxygen glucose deprivation (OGD) were used as models for IRI. The CRT protein level was detected by Western blotting, and mRNA expression of CRT, caspase-3, and caspase-8 was measured by real-time PCR. Immunofluorescence was used to assess the localization of CRT and FasL. The interaction of CRT with FasL was verified by coimmunoprecipitation. SH-SY5Y cell viability was determined by MTT assay, and cell apoptosis was assessed by flow cytometry. The measurement of caspase-8 and caspase-3 activity was carried out using caspase activity assay kits.
  
  
  RESULTS
  After IRI, CRT was upregulated on the neuron surface and bound to FasL, leading to increased viability of OGD-exposed SH-SY5Y cells and decreased activity of caspase-8 and caspase-3.
  
  
  CONCLUSIONS
  This study for the first time revealed that increased CRT inhibited Fas/FasL-mediated neuronal cell apoptosis during the early stage of ischemic stroke, suggesting it to be a potential protector activated soon after IRI.
authors.affiliation: Department of Neurology, Drum Tower Hospital of Nanjing Medical University, Nanjing 210008, China ; Department of Neurology, Northern Jiangsu Province Hospital, Yangzhou 225009, China.
authors.forename: Beilei
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Neurology, Drum Tower Hospital of Nanjing Medical University, Nanjing 210008, China.
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Neurology, Northern Jiangsu Province Hospital, Yangzhou 225009, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Neurology, Drum Tower Hospital of Nanjing Medical University, Nanjing 210008, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D037282:Calreticulin / Q000235:genetics / Q000378:metabolism*; D053148:Caspase 3 / Q000096:biosynthesis; D053181:Caspase 8 / Q000096:biosynthesis; D053222:Fas Ligand Protein / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics / Q000473:pathology; D051379:Mice; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D015427:Reperfusion Injury / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019014:fas Receptor / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D037282:Calreticulin; D053222:Fas Ligand Protein; C491899:Fas protein, mouse; D019014:fas Receptor; C505409:Casp3 protein, mouse; D053148:Caspase 3; D053181:Caspase 8