DLK1-expressing neural progenitor cells promote tissue repair and functional recovery after cervical spinal cord injury.

Spinal cord injury (SCI) elicits a hostile microenvironment characterized by inflammation, gliosis, and disrupted signaling pathways that collectively impede neural repair. Neural progenitor cells (NPCs) represent a promising regenerative approach, yet their survival and differentiation are often compromised in this setting. Here, we investigated whether engineering NPCs to overexpress the Notch pathway modulator Delta-like non-canonical Notch ligand 1 (DLK1) could overcome these limitations and improve functional outcomes after cervical SCI in rats. NPCs were engineered to express DLK1 under a Pax6 promoter-driven expression system, ensuring elevated DLK1 levels during the progenitor state. Following transplantation of DLK1-overexpressing NPCs or control NPCs, we assessed graft survival, lineage differentiation, behavioral performance, and electrophysiological integration over 12 weeks. DLK1-expressing NPCs exhibited significantly greater retention in the injured spinal cord and showed enhanced neuronal differentiation alongside reduced astrocytic commitment compared to controls. Behavioral tests-including forelimb grip strength and CatWalk gait assessments-demonstrated that DLK1-modified NPCs conferred robust improvements in forelimb motor coordination and overall locomotion. Concordantly, electrophysiological recordings revealed increased motor-evoked potential amplitudes and area-under-the-curve values in animals receiving DLK1-transduced NPC grafts, indicative of strengthened synaptic integration within the host motor circuitry.