title: TAT-mediated delivery of neuroglobin attenuates apoptosis induced by oxygen-glucose deprivation via the Jak2/Stat3 pathway in vitro.
abstract: OBJECTIVE
  Neuroglobin (Ngb), an identified globin in vertebrate brain, is a potential novel protective protein against brain ischemia. In our previous study, the human immunodeficiency virus trans-activator of transcription (TAT) protein transduction domain successfully delivered exogenous Ngb into neurons in the mouse, and protected the brain from cerebral ischemia-induced apoptosis. The aim of this study is to investigate the role of TAT-Ngb in attenuating oxygen-glucose deprivation (OGD) induced apoptosis and to explore the possible mechanism.
  
  
  METHODS
  Nerve growth factor (NGF)-induced PC12 cells were divided into (1) the control group, (2) the OGD group (just OGD), (3) the Ngb treatment group (OGD and Ngb treatment), and (4) the TAT-Ngb treatment group (OGD and TAT-Ngb treatment). Cell viability and apoptosis were assessed by the MTT assay and the AnnexinV/propidium iodide (PI) staining, respectively. The mitochondrial transmembrane potential was measured by JC-1 staining. Caspase-3, Bcl-2, Bax, Stat3, Jak2, and Akt were determined by western blot analysis.
  
  
  RESULTS
  Trans-activator of transcription effectively delivered Ngb into NGF-induced PC12 cells. Neuroglobin-mediated neuroprotection rescued cultured cells from OGD. We also confirmed previous findings that TAT-Ngb inhibited mitochondrial apoptosis following OGD. Inhibition of apoptosis by Ac-DEVD-CHO showed that caspase-3 was a crucial factor in OGD-induced apoptosis cascades. AG490, a specific Jak2 inhibitor, attenuated the protective effects of TAT-Ngb. The TAT-Ngb promoted expression of the anti-apoptotic protein Bcl-2 through the Jak2/Stat3 signal pathway, and inhibited apoptosis by blocking caspase-3 activation, while the Jak-Akt-Stat3 signal network was not involved.
  
  
  CONCLUSIONS
  Our results demonstrate that TAT-Ngb can protect neuron-like cells against OGD-induced apoptosis by activating the Jak2/Stat3 pathway.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lin
authors.forename: Bin
authors.initials: B
authors.lastname: Cai
authors.forename: Xie-Hua
authors.initials: XH
authors.lastname: Xue
authors.forename: Ling
authors.initials: L
authors.lastname: Fang
authors.forename: Zhi-Ying
authors.initials: ZY
authors.lastname: Wu
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D015153:Blotting, Western; D015687:Cell Hypoxia / Q000187:drug effects* / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D016503:Drug Delivery Systems; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli; D005914:Globins / Q000008:administration & dosage* / Q000235:genetics; D005947:Glucose / Q000172:deficiency*; D053614:Janus Kinase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000008:administration & dosage* / Q000235:genetics; D000078787:Neuroglobin; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D016716:PC12 Cells; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020032:Tyrphostins / Q000494:pharmacology; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage / Q000235:genetics*
chemical_list: D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D018696:Neuroprotective Agents; D011993:Recombinant Fusion Proteins; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D054322:tat Gene Products, Human Immunodeficiency Virus; D005914:Globins; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D005947:Glucose
keywords: Apoptosis,; Jak2/Stat3; Neuroglobin,; Oxygen–glucose deprivation,; Protein transduction domain,