title: Promoting endothelial function by S-nitrosoglutathione through the HIF-1α/VEGF pathway stimulates neurorepair and functional recovery following experimental stroke in rats.
abstract: BACKGROUND
  For stroke patients, stimulating neurorepair mechanisms is necessary to reduce morbidity and disability. Our previous studies on brain and spinal cord trauma show that exogenous treatment with the S-nitrosylating agent S-nitrosoglutathione (GSNO) - a nitric oxide and glutathione metabolite of the human body - stimulates neurorepair and aids functional recovery. Using a rat model of cerebral ischemia and reperfusion (IR) in this study, we tested the hypothesis that GSNO invokes the neurorepair process and improves neurobehavioral functions through the angiogenic HIF-1α/VEGF pathway.
  
  
  METHODS
  Stroke was induced by middle cerebral artery occlusion for 60 minutes followed by reperfusion in adult male rats. The injured animals were treated with saline (IR group, n=7), GSNO (0.25 mg/kg, GSNO group, n=7), and GSNO plus the HIF-1α inhibitor 2-methoxyestra-diol (2-ME) (0.25 mg/kg GSNO + 5.0 mg/kg 2-ME, GSNO + 2-ME group, n=7). The groups were studied for either 7 or 14 days to determine neurorepair mediators and functional recovery. Brain capillary endothelial cells were used to show that GSNO promotes angiogenesis and that GSNO-mediated induction of VEGF and the stimulation of angiogenesis are dependent on HIF-1α activity.
  
  
  RESULTS
  IR injury increased the expression of neurorepair mediators HIF-1α, VEGF, and PECAM-1 and vessel markers to a limited degree that correlate well with significantly compromised neurobehavioral functions compared with sham animals. GSNO treatment of IR not only remarkably enhanced further the expression of HIF-1α, VEGF, and PECAM-1 but also improved functioning compared with IR. The GSNO group also had a higher degree of vessel density than the IR group. Increased expression of VEGF and the degree of tube formation (angiogenesis) by GSNO were reduced after the inhibition of HIF-1α by 2-ME in an endothelial cell culture model. 2-ME treatment of the GSNO group also blocked not only GSNO's effect of reduced infarct volume, decreased neuronal loss, and enhanced expression of PECAM-1 (P<0.001), but also its improvement of motor and neurological functions (P<0.001).
  
  
  CONCLUSIONS
  GSNO stimulates the process of neurorepair, promotes angiogenesis, and aids functional recovery through the HIF-1α-dependent pathway, showing therapeutic and translational promise for stroke.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Mushfiquddin
authors.initials: M
authors.lastname: Khan
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Tajinder S
authors.initials: TS
authors.lastname: Dhammu
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA ; School of Health Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Matsuda
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Mauhammad
authors.initials: M
authors.lastname: Baarine
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Tejbir Singh
authors.initials: TS
authors.lastname: Dhindsa
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Inderjit
authors.initials: I
authors.lastname: Singh
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA ; Ralph H Johnson VA Medical Center, Charleston, SC, USA.
authors.forename: Avtar K
authors.initials: AK
authors.lastname: Singh
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002545:Brain Ischemia / Q000473:pathology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000187:drug effects*; D008297:Male; D020768:Middle Cerebral Artery / Q000473:pathology; D009043:Motor Activity / Q000187:drug effects; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009416:Nerve Regeneration / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D026422:S-Nitrosoglutathione / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D020521:Stroke / Q000188:drug therapy* / Q000523:psychology; D042461:Vascular Endothelial Growth Factor A / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D014665:Vasodilator Agents; D026422:S-Nitrosoglutathione
keywords: GSNO; HIF-1α; IR; S-nitrosylation; VEGF; angiogenesis; motor function; neuroprotection; neurorepair; stroke; subtle behavior