Fndc5 knockdown significantly decreased neural differentiation rate of mouse embryonic stem cells.

Fibronectin type III domain-containing 5 protein (Fndc5) or peroxisomal protein, is a type I membrane protein that has 209 amino acid residues. Previous studies by our group have shown an increase in its expression after retinoic acid treatment of mouse embryonic stem cells (mESCs) during the process of neural differentiation, leading us to conclude that it might be involved in neurogenesis. In the present study, we have constructed an inducible short hairpin RNA (shRNA) vector that is expressed under induction by doxycycline. Next, we generated a stably transformed mESCs line that expressed shRNA against the Fndc5 gene. The knockdown of Fndc5 was performed in two stages of mESC neural differentiation during and post-neural progenitor (NP) formation. Our results indicated that in the process of NPs formation, decreased Fndc5 expression significantly reduced expression of NPs and mature neuronal markers which modulated neuronal differentiation. Decreased Fndc5 expression during the post-NPs formation stage also caused significant reduction in the levels of mature neuronal markers. Fndc5 knockdown during both stages significantly affected both neuronal and astrocytes maturation. We have concluded that Fndc5 expression is required for the appropriate neural differentiation of mESCs. These data confirm the importance of Fndc5 in the generation and development of the nervous system.