Exogenous Oct4 in combination with valproic acid increased neural progenitor markers: an approach for enhancing the repair potential of the brain.

Attempts are aimed to introduce new approaches toward enhancing the brain's potential for repair in neurodegenerative diseases and traumatic injuries. Here we report an increased expression of pluripotency and progenitor markers within the brain following pretreatment with valproic acid (VPA) and in vivo transfection of inducible Oct4-expressing viral particles. Systemic administration of VPA was performed for one week prior to an intracerebroventricular injection of the Oct4-expressing vector into the right side of the brain. Oct4 expression was induced by doxycycline from day 1 post-transfection for an additional week. Real time-PCR and immunohistofluorescence were used for evaluation of marker expression. Real time-PCR analyses of samples collected from the area of transfection within the injected-lateral ventricle revealed increased expression of some stem cell and progenitor markers, which included endogenous Oct4, Nanog, Klf4, c-Myc, Pax6 and Sox1. Expressions of Oct4, SSEA1 and Nanog were further confirmed by immunohistofluorescence. The increased neural progenitor and pluripotency markers due to Oct4 overexpression did not lead to teratoma formation during a 100day follow-up. Our findings suggest that the application of Oct4 as a reprogramming factor in conjunction with VPA, an epigenetic modifier, might be a potential strategy for increasing the brain's capability to repair itself.