A novel role for hippocalcin in bFGF-induced neurite outgrowth of H19-7 cells

초록

Hippocalcin is a Ca2+ binding protein which is expressed mainly in the pyramidal nerve cell of the hippocampus, but the mechanism and functions underlying hippocalcin in the brain remains unclear. To elucidate a role of hippocalcin, we utilized a conditionally immortalized hippocampal cell line (H19-7). We show here that bFGF-induced hippocalcin expression is involved in neurite outgrowth of H19-7cells. Increased expression of hippocalcin dramatically elongated neurites induced by bFGF stmulation. Hippcalcin suppression blocked bFGF-induced neurite outgrowth and NeuroD, a neuronal differentiation factor, expression. Stimulation of bFGF resulted in the activation of phospholipase- (PLC- ). Hippocalcin expression by bFGF stimulation was fully blocked by both the PLC- inhibitor, U73122, suggesting that hippocalcin expression by bFGF stimulation is dependent on phospholipase- (PLC- ). Moreover, U73122 completely blocked bFGF-induced neurite outgrowth and NeuroD expression. Taken together, these results suggest for the first time that bFGF induces hippocalcin expression through PLC- activation, which leads to neurite outgrowth in H19-7 cells.