title: 14,15-epoxyeicosatrienoic acid promotes production of brain derived neurotrophic factor from astrocytes and exerts neuroprotective effects during ischaemic injury.
abstract: 14,15-Epoxyeicosatrienoic acid (14,15-EET) is abundantly expressed in brain and exerts protective effects against ischaemia. 14,15-EET is hydrolysed by soluble epoxide hydrolase (sEH). sEH-/-mice show a higher level of 14,15-EET in the brain. Astrocytes play a pivotal role in neuronal survival under ischaemic conditions. However, it is unclear whether the neuroprotective effect of 14,15-EET is associated with astrocytes.
  
  
  
  A mouse model of focal cerebral ischaemia was induced by middle cerebral artery occlusion. Oxygen-glucose deprivation/reoxygenation (OGD/R) was performed on cultured murine astrocytes, neurons and a human cell line. Cell viabilities were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. The mRNA expressions were quantified by real-time PCR. Brain derived neurotrophic factor (BDNF) concentration was measured by ELISA. Protein expressions were quantified by Western blotting. BDNF and peroxisome proliferators-activated receptor gamma (PPAR-γ) expressions were analysed by confocal microscopy.
  
  
  
  Decreased infarct volumes, elevated BDNF expression and increased numbers of BDNF/GFAP Glial Fibrillary Acidic Protein double-positive cells were observed in the ischaemic penumbra of sEH-/-mice. The decreased infarct volumes of sEH-/-mice were diminished by intracerebroventricular injection of a blocker of BDNF receptor. 14,15-EET increases BDNF expression and cell viability of murine astrocytes and U251 cells by BDNF-TrkB Tyrosine receptor kinase-B-extracellular signal-regulated kinase 1/2 signalling during OGD/R. 14,15-EET protects neurons from OGD/R by stimulating the production of astrocyte-derived BDNF. 14,15-EET stimulates the production of astrocyte-derived BDNF through PPAR-γ/p-cAMP-response element binding protein signal pathways.
  
  
  
  Our study demonstrates the importance of 14,15-EET-mediated production of astrocyte-derived BDNF for enhancing viability of astrocytes and protecting neurons from the ischaemic injury and provides insights into the mechanism by which 14,15-EET is involved in neuroprotection.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: L
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: R
authors.initials: R
authors.lastname: Dong
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: C
authors.initials: C
authors.lastname: Tao
authors.affiliation: Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: R
authors.initials: R
authors.lastname: Zheng
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
authors.forename: S
authors.initials: S
authors.lastname: Zhu
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism* / Q000517:prevention & control*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004851:Epoxide Hydrolases / Q000235:genetics; D006801:Humans; D020935:MAP Kinase Signaling System; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018696:Neuroprotective Agents / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018696:Neuroprotective Agents; C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D004851:Epoxide Hydrolases; D015126:8,11,14-Eicosatrienoic Acid
keywords: 14,15-epoxyeicosatrienoic acid; astrocyte; brain derived neurotrophic factor; cerebral ischaemia; extracellular signal-regulated kinase 1/2; peroxisome proliferators-activated receptor gamma