Development of neuronal cell-type inducible GM-CSF gene expression system and combined cell therapy in spinal cord injury model

Abstract

Promising therapy is needed to treat spinal cord injury (SCI) associated with permanent neurological damage. It is difficult to expect a sufficient therapeutic outcome by a single treatment method. Therefore, a strategy combining two or more techniques might be better for improving therapeutic effects.In this study, it was designed that a merged treatment strategy using neural stem cells (NSCs) introduced with neuronal cell-type inducible transgene expression system controlled by a neuronal specific enolase (NSE) promoter to maximize the therapeutic efficiency. The luciferase gene was chosen to confirm whether this combined system was working properly prior to using a therapeutic gene. The luciferase expression levels of NSCs introduced with a neuronal cell-type inducible luciferase expression system (NSE-Luci) or with a general luciferase expression system (SV-Luci) were measured and compared in vitro and in vivo.After verified neuronal cell-specific gene expression by luciferase gene, therapeutic gene, GM-CSF, was substituted with luciferase gene. Neuronal cell type-inducible GM-CSF expression system (NSE-GMCSF) compared with a general GM-CSF expression system (SV-GMCSF) in vitro and in vivo. The results show that neural stem cells introduced with a neuronal cell-type inducible luciferase expression system (NSE-Luci) showed a high level of luciferase expression compared to neural stem cells introduced with a general luciferase expression system (SV-Luci). And also therapeutic gene system, a neuronal cell-type inducible GM-CSF expression system (NSE-GMCSF) was higher expressed GM-CSF than a general GM-CSF expression system (SV-GMCSF). A neuronal cell-type inducible gene expression system has been demonstrated that it’s suitable for NSCs in a merged-treatment strategy. Therefore, it is suggested that this merged-treatment strategy based on NSCs and a neuronal

cell-type–inducible gene expression system is a promising tool for treatment of neurodegenerative disorder, including SCI.