title: Hypoxia-specific, VEGF-expressing neural stem cell therapy for safe and effective treatment of neuropathic pain.
abstract: Vascular endothelial growth factor (VEGF) is an angiogenic cytokine that stimulates the differentiation and function of vascular endothelial cells. VEGF has been implicated in improving nervous system function after injury. However, uncontrolled overexpression of VEGF increases the risk of tumor formation at the site of gene delivery. For this reason, VEGF expression needs to be strictly controlled. The goal of the present study was to understand the effects of hypoxia-induced gene expression system to control VEGF gene expression in neural stem cells (NSCs) on the regeneration of neural tissue after sciatic nerve injury. In this study, we used the erythropoietin (Epo) enhancer-SV40 promoter system (EpoSV-VEGF-NSCs) for hypoxia-specific VEGF expression. We used three types of NSCs: DsRed-NSCs as controls, SV-VEGF-NSCs as uncontrolled VEGF overexpressing NSCs, and EpoSV-VEGF-NSCs. For comparison of VEGF expression at normoxia and hypoxia, we measured the amount of VEGF secreted. VEGF expression decreased at normoxia and increased at hypoxia for EpoSV-VEGF-NSCs; thus, EpoSV-VEGF-NSCs controlled VEGF expression, dependent upon oxygenation condition. To demonstrate the therapeutic effect of EpoSV-VEGF-NSCs, we transplanted each cell line in a neuropathic pain sciatic nerve injury rat model. The transplanted EpoSV-VEGF-NSCs improved sciatic nerve functional index (SFI), mechanical allodynia, and re-myelination similar to the SV-VEGF-NSCs. Additionally, the number of blood vessels increased to a level similar to that of the SV-VEGF-NSCs. However, we did not observe tumor generation in the EpoSV-VEGF-NSC animals that were unlikely to have tumor formation in the SV-VEGF-NSCs. From our results, we determined that EpoSV-VEGF-NSCs safely regulate VEGF gene expression which is dependent upon oxygenation status. In addition, we found that they are therapeutically appropriate for treating sciatic nerve injury.
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Hye-Lan
authors.initials: HL
authors.lastname: Lee
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Hye Yeong
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Yeomin
authors.initials: Y
authors.lastname: Yun
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Oh
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Lihua
authors.initials: L
authors.lastname: Che
authors.affiliation: Department of Bioengineering, College of Engineering, Hanyang University, Seoul, South Korea.
authors.forename: Minhyung
authors.initials: M
authors.lastname: Lee
authors.affiliation: Spine & Spinal Cord Institute, Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, South Korea. Electronic address: hayoon@yuhs.ac.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Ha
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D002460:Cell Line; D004921:Erythropoietin / Q000235:genetics; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D008297:Male; D051379:Mice; D058953:Neural Stem Cells / Q000378:metabolism / Q000637:transplantation*; D009437:Neuralgia / Q000235:genetics / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D042461:Vascular Endothelial Growth Factor A; D004921:Erythropoietin
keywords: Erythropoietin enhancer; Neural stem cells; Neuropathic pain; Sciatic nerve injury; Tumor; Vascular endothelial growth factor