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Lian Jin, Hong,Pennant, William A.,Hyung Lee, Min,Su, Sung,Ah Kim, Hyun,Lu Liu, Meng,Soo Oh, Jin,Cho, Joon,Nyun Kim, Keung,Heum Yoon, Do,Ha, Yoon Lippincott Williams Wilkins, Inc. 2011 1528-1159) Vol.36 No.11
STUDY DESIGN.: An in vitro neural hypoxia model and rat spinal cord injury (SCI) model were used to assess the regulation of therapeutic vascular endothelial growth factor (VEGF) gene expression in mouse neural stem cells (mNSCs) by the EPO (erythropoietin) enhancer or RTP801 promoter. OBJECTIVE.: To increase VEGF gene expression in mNSCs under hypoxic conditions in SCI lesions but avoid unwanted overexpression of VEGF in normal sites, we developed a hypoxia-inducible gene expression system consisting of the EPO enhancer and RTP801 promoter fused to VEGF or the luciferase gene, then transfected into mNSCs. SUMMARY OF BACKGROUND DATA.: On the basis of the ischemic response in the injured area, poor cell survival at the transplantation site is a consistent problem with NSC transplantation after SCI. Although VEGF directly protects neurons and enhances neurite outgrowth, uncontrolled overexpression of VEGF in uninjured tissue may cause serious adverse effects. To effectively improve NSC survival in ischemic sites after transplantation, we evaluated mNSCs modified by a hypoxia-inducible VEGF gene expression system in an SCI model. METHODS.: Hypoxia-inducible luciferase or VEGF plasmids were constructed using the EPO enhancer or RTP801 promoter. The effect of these systems on targeted gene expression and cell viability was evaluated in mNSCs in both hypoxic in vitro injury and a rat SCI model in vivo. RESULTS.: The gene expression system containing the EPO enhancer or RTP801 promoter significantly increased the expression of the luciferase reporter gene and therapeutic VEGF gene under hypoxic conditions. The Epo-SV-VEGF plasmid transfection group had significantly fewer apoptotic cells in vitro. This system also augmented cell viability in the in vivo SCI model. CONCLUSION.: These results strongly suggest the potential utility of mNSCs modified by a hypoxia-inducible VEGF gene expression system in the development of effective stem cell transplantation protocols in SCI.
Oh, Jin Soo,Kim, Keung Nyun,An, Sung Su,Pennant, William A,Kim, Hyo Jin,Gwak, So-Jung,Yoon, Do Heum,Lim, Mi Hyun,Choi, Byung Hyune,Ha, Yoon Pergamon Press ; Elsevier Science Ltd ; Elsevier S 2011 Cell transplantation Vol.20 No.6
<P>The low survival rate of graft stem cells after transplantation into recipient tissue is a major obstacle for successful stem cell therapy. After transplantation into the site of spinal cord injury, the stem cells face not only hypoxia due to low oxygen conditions, but also a lack of nutrients caused by damaged tissues and poor vascular supply. To improve the survival of therapeutic stem cells after grafting into the injured spinal cord, we examined the effects of cotransplanting mouse neural stem cells (mNSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) on mNSC viability. The viability of mNSCs in coculture with AT-MSCs was significantly increased compared to mNSCs alone in an in vitro injury model using serum deprivation (SD), hydrogen peroxide (H(2)O(2)), and combined (SD + H(2)O(2)) injury mimicking the ischemic environment of the injured spinal cord. We demonstrated that AT-MSCs inhibited the apoptosis of mNSCs in SD, H(2)O(2), and combined injury models. Consistent with these in vitro results, mNSCs transplanted into rat spinal cords with AT-MSCs showed better survival rates than mNSCs transplanted alone. These findings suggest that cotransplantation of mNSCs with AT-MSCs may be a more effective transplantation protocol to improve the survival of cells transplanted into the injured spinal cord.</P>
Hypoxia-specific VEGF-expressing neural stem cells in spinal cord injury model
Oh, Jin Soo,An, Sung Su,Gwak, So-Jung,Pennant, William A.,Kim, Keung Nyun,Yoon, Do Heum,Ha, Yoon Lippincott Williams Wilkins, Inc. 2012 NEUROREPORT - Vol.23 No.3
We established three stable neural stem cell (NSC) lines to explore the possibility of using hypoxia-specific vascular endothelial growth factor (VEGF) expressing NSC lines (EpoSV-VEGF NSCs) to treat spinal cord injury. The application of EpoSV-VEGF NSCs into the injured spinal cord after clip compression injury not only showed therapeutic effects such as extended survival and angiogenesis, but also displayed its safety profile as it did not cause unwanted cell proliferation or angiogenesis in normal spinal cord tissue, as EpoSV-VEGF NSCs consistently showed hypoxia-specific VEGF expression patterns. This suggests that our EpoSV-VEGF NSCs are both safe and therapeutically efficacious for the treatment of spinal cord injury. Furthermore, this hypoxia-inducible gene expression system may represent a safe tool suitable for gene therapy.
Effect of primate bone marrow stromal cells on survival and neurite outgrowth
Kim, Keung Nyun,Guest, James D.,Oh, Jin Soo,Pennant, William A.,Yoon, Do Heum,Ha, Yoon Lippincott Williams Wilkins, Inc. 2010 NEUROREPORT - Vol.21 No.13
We tested whether bone marrow stromal cells (BMSCs) could enhance the survival and neurite growth of dorsal root ganglia (DRG) through substrate effects or secreted factors. Our results showed that in DRG with BMSCs and BMSC-conditioned media cultures compared with DRG-fibroblast cultures, there was a significant increase in the number and length of, area covered by, and number of cells with definite neurites. In cytokine assays with conditioned media, vascular endothelial growth factor, granulocyte macrophage colony-stimulating factor, and IL-6 secreted by BMSCs may contribute to observed neurotrophic effects. These findings indicate that BMSCs of adult Macaca fascicularis increased neuronal survival and promoted neurite outgrowth of DRG by means of secretory factors.
Hypoxia-induced expression of VEGF in the organotypic spinal cord slice culture :
An, Sung Su,Pennant, William A.,Ha, Yoon,Oh, Jin Soo,Kim, Hyo Jin,Gwak, So-Jung,Yoon, Do Heum,Kim, Keung Nyun Ovid Technologies (Wolters Kluwer) - Lippincott Wi 2011 NEUROREPORT - Vol.22 No.2
<P>We used the erythropoietin enhancer and Simian virus-40 promoter to create a hypoxia-inducible gene expression system to investigate the effect of vascular endothelial growth factor (VEGF) gene therapy on neuroprotection and neurogenesis in organotypic spinal cord slice culture. The organotypic spinal cord slice culture transfected with pEpo-SV-VEGF expressed the highest amount of VEGF under hypoxic conditions and showed decreased apoptosis and increased proliferation, and evidence of neurogenesis. Our results show that the hypoxia-induced VEGF expression in an organotypic spinal cord slice culture may lead to an optimal treatment for spinal cord injury.</P>