Enhanced generation of new neurons from activated endogenous neural stem cells by PTBP1 knockdown following spinal cord injury

Regeneration of new neurons and reconstruction of synaptic connections with host neurons remain a key research focus in spinal cord injury (SCI). Spinal endogenous neural stem cells (NSCs) are activated following SCI and possess neuronal differentiation potential, yet their neurogenic ability is constrained by insufficient mechanistic insight. Polypyrimidine tract binding protein 1 (PTBP1), a key RNA-binding protein, modulates pre-mRNA alternative splicing to control neuronal differentiation during neural development. In this study, we examined the effects of PTBP1 knockdown on neuronal differentiation of NSCs and neurogenesis in the lesion core of rats following SCI. Our results showed PTBP1 was highly expressed in NSCs and weakly expressed in neurons and knockdown of PTBP1 in NSCs promoted NSC differentiation into neurons in vitro . Using PTBP1-shRNA-lentiviral vectors expressing GFP, we knocked down PTBP1 in activated endogenous NSCs surrounding the lesion site at 5 days post-SCI. Our results demonstrated PTBP1 suppression in activated spinal NSCs enhanced the generation of new neurons at the lesion center and further improved functional recovery in SCI animal models. Additionally, we transplanted NSC grafts following PTBP1 knockdown into injured rats. We further investigated the origin of new neurons in the lesion center. Our findings revealed that new neurons in the lesion core originated from spinal NSCs rather than being reprogrammed from astrocytes. These results identify a novel role for PTBP1 in regulating the fate specification of activated NSCs post-SCI and highlight the potential of generating endogenous neurons from activated NSCs, suggesting the clinical translatability of PTBP1 suppression for SCI treatment.