title: Down-regulation of Homer1 attenuates t-BHP-induced oxidative stress through regulating calcium homeostasis and ER stress in brain endothelial cells.
abstract: Endothelial dysfunction in brain endothelial cells contributes to vasogenic cerebral edema and increased mortality after various neurological diseases. The postsynaptic density protein Homer1 plays an important role in neuronal synaptic activity and is extensively involved in neurological disorders. The present study investigated the role of Homer1 in modulating cell survival using an in vitro endothelial dysfunction model in murine brain endothelial cells (mBECs). Treatment with tert-butyl hydroperoxide (t-BHP) induced a dose-dependent toxicity in mBECs, with no effects on Homer1 expression and distribution. Knockdown of Homer1 using specific siRNA significantly alleviated lactate dehydrogenase (LDH) release, increased cell viability, and ultimately decreased apoptosis after t-BHP treatment. Moreover, Homer1 knockdown attenuated t-BHP-induced ROS generation, lipid peroxidation and mitochondrial dysfunction, as evidenced by loss of mitochondrial membrane potential (MMP), ATP synthesis collapse and mitochondrial swelling. The results of Ca(2+) imaging showed that Homer1 was involved in inositol trisphosphate receptors (IP3R)- and ryanodine receptor (RyR)-mediated intracellular Ca(2+) release, and also mediated t-BHP-induced Ca(2+) release from the endoplasmic reticulum (ER). In addition, knockdown of Homer1 significantly prevented activation of ER stress markers induced by t-BHP exposure. All these results showed that Homer1 is involved in t-BHP-induced endothelial dysfunction in mBECs, and may be an ideal candidate for searching gene intervention strategy for preventing endothelial oxidative stress in vitro.
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiao Tong University, Xi'an Jiao Tong University, Xi'an, Shaanxi Province 710004, China.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiao Tong University, Xi'an Jiao Tong University, Xi'an, Shaanxi Province 710004, China.
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Shaanxi Nuclear Industry 215 Hospital, Baoji, Shaanxi 712000, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Xie
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiao Tong University, Xi'an Jiao Tong University, Xi'an, Shaanxi Province 710004, China.
authors.forename: Chong-Xiao
authors.initials: CX
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiao Tong University, Xi'an Jiao Tong University, Xi'an, Shaanxi Province 710004, China.
authors.forename: Ren
authors.initials: R
authors.lastname: Zhou
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiao Tong University, Xi'an Jiao Tong University, Xi'an, Shaanxi Province 710004, China. Electronic address: songjl@fmmu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D000072233:Homer Scaffolding Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D020122:tert-Butylhydroperoxide / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D000072233:Homer Scaffolding Proteins; C000606623:Homer1 protein, mouse; D020122:tert-Butylhydroperoxide; D002118:Calcium
keywords: Calcium homeostasis; ER stress; Homer1; Oxidative stress