Intra-Amniotic Delivery of CRMP4 siRNA Improves Mesenchymal Stem Cell Therapy in a Rat Spina Bifida Model

Neural tube defects (NTDs) result in prenatal mortality and lifelong morbidity, and available treatments have limited efficacy. We previously suggested that prenatal bone marrow-derived mesenchymal stem cell (BMSC) transplantation could treat neuron deficiency in NTD rats; however, BMSC-based therapy is limited by the low survival rate of BMSCs when used to treat severe NTDs. Herein, a new therapy using combined BMSC transplantation and small interfering RNA of collapsin response mediator protein 4 (CRMP4 siRNA), which was identified as a novel potential target for the NTD treatment, is proposed. The intra-amniotic CRMP4 siRNA, BMSC, and CRMP4 siRNA + BMSC injections repaired skin lesions, improved motor neural function, reduced neuronal apoptosis, and promoted expression of neural differentiation-related molecules and neurotrophic factors in the spinal cord of spina bifida rat fetuses. Therapeutic effects in the CRMP4 siRNA + BMSC injection group were superior to those of the CRMP4 siRNA only or BMSC only injection groups. CRMP4 siRNA + BMSC injection resulted in a 45.38% reduction in the skin lesion area and significantly shorter latency and higher amplitude of motor-evoked potentials (MEPs) in spina bifida fetuses. Our results suggest that intrauterine Ad-CRMP4 siRNA delivery with BMSCs is an innovative platform for developing fetal therapeutics to safely and efficaciously treat NTDs.