The Effects And Underlying Mechanism After Overexpression Of The Transcription Factors OCT4 And KLF4 In Injured Spinal Cord

Objective:Spinal cord injury(SCI)followed by astrogliosis and glial scar formation is viewed as a major obstacle that hinders axonal regeneration and functional recovery.Considering the importance of regulating the glial scar,we intended to investigate the effect of the transcription factors OCT4 and KLF4 on glial scar formation and the underlying mechanism after spinal cord contusion injury in transgenic mice.Methods:After spinal cord contusion,doxycycline-containing water is used to induce OCT4 and KLF4 transcription factors expression in vivo.Hind limbs motor function of mice is assessed using the open field Basso Mouse Scale(BMS)locomotor scale system.Moreover,immunofluorescence,Western blotting,H&E,Fast blue are used to analyze glial scar formation,remyelination,neural regeneration after SCI.In addition,astrocytes extracted from brain of neonatal mice are cultured in proper medium.Western blotting,immunofluorescence and scratch assay at proper time are applied to investigated the underlying mechanism.Results:Western blotting,immunofluorescence and functional evaluation suggested that glial fibrillary acidic protein(GFAP)expression was decreased in the lesion area,the porosity of scar was increased,and remyelination was improved and that mice overexpressing the transcription factors OCT4 and KLF4 had higher BMS scores than control mice.Moreover,using immunofluorescence,western blotting and a cell scratch assay,we discovered that some astrocytes were reprogrammed into neural stem celllike cells and that the migration ability of astrocytes was significantly inhibited in vitro in the presence of the transcription factors OCT4 and KLF4.In addition,we demonstrated that the Hippo/Yap pathway was activated after the two transcription factors were expressed in astrocytes.Conclusions:In summary,these results suggest that the transcription factors OCT4 and KLF4 synergistically ameliorate astrocytic glial scarring,promote remyelination and may eventually improve motor function after SCI.