Abstract
Neuritogenesis is the process underling nervous system regeneration; however, optimal extracellular signals that can promote neuronal regenerative activities require further investigation. Previously, we developed a novel method for inducing neuronal differentiation in rat PC12 cells using temperature-controlled repeated thermal stimulation (TRTS) with a heating plate. Based on neurogenic sensitivity to TRTS, PC12 cells were classified as either hyper- or hyposensitive. In this study, we aimed to investigate the mechanism of hyposensitivity by establishing two PC12-derived subclones according to TRTS sensitivity during differentiation: PC12-P1F1, a hypersensitive subclone, and PC12-P1D10, a hyposensitive subclone. To characterize these subclones, cell size and neuritogenesis were evaluated in subclones treated with nerve growth factor (NGF), bone morphogenetic protein (BMP), or various TRTS. No significant differences in cell size were observed among the parental cells and subclones. BMP4- or TRTS-induced neuritogenesis was increased in PC12-P1F1 cells compared to that in the parental cells, while no neuritogenesis was observed in PC12-P1D10 cells. In contrast, NGF-induced neuritogenesis was observed in all three cell lines. Furthermore, a BMP inhibitor, LDN-193189, considerably inhibited TRTS-induced neuritogenesis. These results suggest that the BMP pathway might be required for TRTS-induced neuritogenesis, demonstrating the useful aspects of these novel subclones for TRTS research.