Intra-amniotic delivery of CRMP4 siRNA improves mesenchymal stem cell therapy in a rat spina bifida model

Abstract Neural tube defects (NTDs) result in are complex congenital malformations leading to prenatal mortality and lifelong morbidity. The and available treatments have limited efficacy. We previously suggested prenatal bone mesenchymal stem cell (BMSC) transplantation during embryonic development 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 effector target for the NTD treatment of spina bifida in a rat fetal model, is proposed. The in utero intra-amniotic CRMP4 siRNA, BMSCs, and CRMP4 siRNA + BMSCs 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 CRMP4 siRNA only or BMSC only injection groups. CRMP4 siRNA + BMSC injection resulted in 45.4% 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 The intrauterine Ad-CRMP4 siRNA delivery with BMSC transplantation was effective and resulted in a significant, clinically relevant improvement in neurological function and accelerated skin repair in NTD rat fetuses by promoting neural differentiation and inhibiting neuronal death. Intra-amniotic delivery of CRMP4 siRNA + BMSCs is an innovative platform for developing fetal therapeutics to safely and efficaciously treat NTDs congenital diseases.