title: Silencing of Id2 attenuates hypoxia/ischemia-induced neuronal injury via inhibition of neuronal apoptosis.
abstract: Cerebral ischemic stroke has long been recognized as a prevalent and serious neurological disease that was associated with high mortality and morbidity. However, the current therapeutic protocols remain suboptimal with major mechanisms underlying stroke urgently warranted. Inhibitor of DNA binding/differentiation 2 (Id2) is found to be up-regulated in neuronal cells following hypoxia/ischemia (H/I). This study was aimed to investigate whether knockdown of Id2 in neuronal cells could protect them from hypoxic and ischemic injury both in vitro and in vivo. Flow cytometric analysis was employed to assess neuronal apoptosis in CoCl2-treated neuroblastoma B35 cells engineered to overexpress or knockdown Id2 expression. In vivo knockdown of Id2 was performed in Sprague-Dawley rats by a single intracerebroventricular injection of Cy3-labeled and cholesterol-modified Id2-siRNA. We found that knockdown of Id2 attenuated H/I-induced neuronal apoptosis in vitro while overexpression of Id2 produced an opposite effect. In a rat model of middle cerebral artery occlusion (MCAO), in vivo knockdown of Id2 significantly improved neurological deficits, reduced the volume of ischemic infarction and diminished the neuronal apoptosis in the penumbra area. Double immunofluorescence staining showed less co-localization of retinoblastoma tumor suppressor protein (Rb)-Id2 but greater co-localization of Rb-E2F1 in the penumbra area. Cell cycle assay further demonstrated that Id2 knockdown induced G0/G1 cell cycle arrest in CoCl2-treated B35 cells. The present data support the implication of Id2 in the modulation of H/I-induced neuronal apoptosis and may provide a potential therapeutic option to protect brain tissues from ischemic injury by inhibition of its expression.
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Liemei
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Medicine and UC San Diego Moores Cancer Center, University of California-San Diego, CA, United States.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Quanmin
authors.initials: Q
authors.lastname: Nie
authors.affiliation: Department of Neurosurgery, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ren
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Qinhua
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, Longyan First Hospital affiliated to Fujian Medical University, Fujian Province, China. Electronic address: 157223552@qq.com.
authors.forename: Shuanglin
authors.initials: S
authors.lastname: Que
authors.affiliation: Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. Electronic address: qiuzhoub@hotmail.com.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Qiu
mesh_terms: D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D055785:Gene Knockdown Techniques; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D051797:Inhibitor of Differentiation Protein 2 / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C497451:Id2 protein, rat; D051797:Inhibitor of Differentiation Protein 2
keywords: Hypoxia; Id2; Ischemia; Neuronal apoptosis; Neuronal injury; siRNA