title: Integrin β8 signaling in neonatal hypoxic-ischemic brain injury.
abstract: Integrin β8 is a key regulator of vascular homeostasis in brain development and in vitro studies show that β8 protects against oxygen-glucose deprivation-induced neuronal apoptosis. However, the role β8 plays in vivo in neonatal rats with hypoxic-ischemic (HI) brain injury is not known. Here, we report the function of β8 and signaling pathways involved in neuroprotection after neonatal brain HI. Neonatal HI model was performed in postnatal day 10 rats by ligating the right common carotid artery, followed by hypoxia exposure. Expressions of β8 were determined by immunohistochemistry, immunofluorescence, reverse transcription polymerase chain reaction, and western blot. We used lentiviral vector-mediated β8 RNAi to inhibit integrin β8, GM6001 to inhibit matrix metalloprotease, and the TGF-β1 neutralizing antibody 1d11 to inhibit TGF-β1. The expression of vascular endothelial growth factor, ERK1/2 and p-ERK1/2, Bcl-2, Bax, and cleaved caspase 3 (CC3) were detected by western blot. Cellular apoptosis was detected with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling. β8 was mainly localized to astrocytes and upregulated immediately upon HI. When β8/TGF-β1 was inhibited, phosphorylated ERK1/2 was downregulated, followed by the downregulation of vascular endothelial growth factor (VEGF) and Bcl-2/Bax, and upregulation of CC3 and cellular apoptosis. The activation of TGF-β1 and ERK1/2 are involved in β8-induced VEGF expression and neuronal survival. The anti-apoptotic effect of β8 may be attributed to regulation of Bcl-2/Bax balance and caspase 3. β8 might be a potential target for therapeutic intervention in neonates with HI brain injury.
authors.affiliation: Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, Sichuan, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Qu
authors.forename: Binzhi
authors.initials: B
authors.lastname: Tang
authors.forename: Fengyan
authors.initials: F
authors.lastname: Zhao
authors.forename: Tao
authors.initials: T
authors.lastname: Xiong
authors.forename: Donna
authors.initials: D
authors.lastname: Ferriero
authors.forename: Dezhi
authors.initials: D
authors.lastname: Mu
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004151:Dipeptides / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D007839:Functional Laterality; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D020287:In Situ Nick-End Labeling; D039641:Integrin beta Chains / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000906:Antibodies; D004151:Dipeptides; D005904:Glial Fibrillary Acidic Protein; D039641:Integrin beta Chains; C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D011480:Protease Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D051028:bcl-2-Associated X Protein; C094865:integrin beta8