Differentiation of rhesus monkey bone marrow mesenchymal stem cells into neuron-like cells induced by sonic hedgehog: Significance of its signal molecule expression changes compared with retinoic acid scheme / 中国组织工程研究

ABSTRACT

BACKGROUND: Present studies have demonstrated that during neural development, differentiation of neural stem cells (NSCs) was affected by various regulatory factors from surrounding microenvironment. Sonic hedgehog (Shh) is a key induction signal during neural fetal development, and can be an effective inductor to regulate differentiation of neural cells. OBJECTIVE: To investigate the signal transduction pathway of SHH for differentiation of rhesus monkey bone marrow mesenchymal stem cells (BMSCs) into of neuron-like cells by sonic hedgehog factor. METHODS: Rhesus monkey BMSCs were isolated and cultured by conventional density gradient centrifugation. BMSCs in the induction group were treated with L-DMEM containing FGF2, B27 and fetal bovine serum for preinduction of 24 hours, and then with DMEM supplemented with 0.5 μmol/L retinoic acid or 400 μmol/L SHH for 8 days. Non-induced cells served as control group. Following labeling with neuron enolase, positive cells were screened by flow cytometry. RT-PCR and Western-blot were used to detect SHH- and retinoic acid-induced cell membrane receptor and intracellular signal protein changes. RESULTS AND CONCLUSION: SHH specific membrane receptor Ptc, retinoic acid specific receptor RARα, signal protein molecule ptch1 and Smad expressed in normal cells. Ptc expression upregulated in SHH-induced cells. High expression lasted for a long time with induction time, which was significantly stronger compared with the retinoic acid and control groups (P < 0.01). Intracellular ptch1 protein molecule expression showed similar tendency as this, but could not induce upregulation of RARα expression. During induction, retinoic acid-stimulated cells did not activate Ptc pathway. Four days following induction, RARα expression upregulated and lasted till 6 days, but there were no significant differences. No significant change in ptch1 expression was determined. SHH- and retinoic acid-induced cell Smad molecule expression upregulated, but no significant difference was determined. Results verified that SHH-induced scheme participated in cell induction and differentiation by persistently activating its specific receptors. However, there was no significant receptor pathway crossing between retinoic acid-induced and SHH-induced schemes.