Self-Assembling Peptide Nanofiber Containing Long Motif of Laminin Induces Neural Differentiation, Tubulin Polymerization, and Neurogenesis: In Vitro, Ex Vivo, and In Vivo Studies

Spinal cord injury (SCI) in humans stayed a ruining and healless disorder. Since longer laminin motif (CQAASIKVAV (CQIK)) better mimics conformation of native region in active site than isoleucine-lysine-valine-alanine-valine (IKVAV) and resulted in improved cellular response so, for the first time in this study, CQIK bounded with two glycines spacer and (RADA)(4) as a self-assembling peptide nanofiber backbone (-CQIK) was used. The purpose of this study was to investigate the role of -CQIK in neural differentiation of human endometrial-derived stromal cells (hEnSCs) in vitro, tubulin polymerization ex vivo, and assess the supportive effect of this hydrogel in an animal model of chronic SCI. Results disclosed that proton concentration has direct effect on hEnSCs membrane damage but not on neuroblastoma cells. However, cell viability of neuroblastoma encapsulated into -CQIK was higher than hEnSCs at the concentration of 0.125 % v/w. Gene expression data confirmed neurogenesis, TH over-expression, and glial fibrillary acidic protein (GFAP) suppression eventually through alpha 6 and beta 1 integrin site. However, it revealed higher neurogenesis as compared to bone morrow homing peptides (BMHP). Although, Basso, Beattie, Bresnahan (BBB) score of chronic model of SCI in rat was higher than control and phosphate-buffered saline (PBS) group but significantly was less than BMHP group. However, -CQIK had induced neurite outgrowth and myelination and inhibited astrogliosis. Tubulin polymerization data using UV spectroscopy showed higher degree of polymerization. However, tubulin polymerization was dependent on nanofiber concentration. Based on our results, it might be concluded that peptidic nanofiber containing long motif of laminin holds great promise for spinal cord injury recovery with increment of neurogenesis and astrogliosis decrement.