Document Type : Original Article
CENTER FOR CELLULAR AND MOLECULAR RESEARCH, KURDISTAN UNIVERSITY OF MEDICAL SCIENCES. SANANDAJ, IRAN
Objective: To evaluate and compare the gene expression profiles of Ninjurin-1 and Ninjurin- 2 with the expressions of L1 family of cell adhesion molecules (NCAM-L1) neural cell adhesion molecules (NCAM) and N-cadherin during the course of neural differentiation of mouse neural stem cells (NSCs).
Materials and Methods: Briefly for neural stem cell isolation the frontal part of an adult mouse brain was minced in phosphate buffered saline (PBS) and digested by an enzyme solution which contained hyaluronidase and trypsin. Isolated cells were cultured in medium supplemented by epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). After seven days primary neurospheres appeared in culture medium. After transfer to poly-L-ornithine coated dishes that contained culture medium supplemented with 1% fetal bovine serum (FBS) the primary neurospheres differentiated into neural-like and neuroglial-like cells. Differentiated cells were examined by morphological immunocytochemical and molecular evaluations.
Results: Our results showed that isolated cells from the preventricular area of mouse adult brain proliferated in medium which contained EGF and bFGF and expansion of the cells continued until passage 14 without losing morphological and neurogenesis capacity. Multiple passaging confirmed the stemness nature of the isolated cells. The isolated NSCs were able to differentiate into neural-like and neuroglial-like cells after transfer to poly-L-ornithine coated dishes that contained culture medium supplemented with 1% FBS. Molecular studies for NCAM NCAM-L1 and N-Cadherin genes as well as immunocytochemical analysis for NCAM-L1 and NCAM proved the differentiation. Our data also revealed for the first time gene expression profiling of Ninurin-1 and Ninjurin-2 two novel cell adhesion molecules (CAMs) during the course of differentiation of neural stem cells.
Conclusion: The induction of neural differentiation in mouse NSCs initiates the expression of NCAM-L1, NCAM, and N-cadherin which can be the proof of complete neural differentiation. In addition, our results indicate that the expression of Ninjurin-1 increases after neural induction much like the expressions of NCAM-L1, NCAM, and N-cadherin. This data suggests the probable importance of Ninjurin-1 in both the morphology and function of neural cells. The data in this study also reveals that the expression of Ninjurin-2, in contrast with Ninjurin-1, initiates and continues until the differentiation termination point. This suggests that although Ninjurin-1 and Ninjurin-2 share conserved hydrophobic regions for their transmembrane domains, their roles in nerve cells are probably different.