Lithium inhibits apoptosis of mouse neural progenitor cells

As undifferentiated precursor cells in the CNS, neural progenitor cells (NPCs) supply new neurons and glial cells to repair damage within the adult brain. Recently, NPCs were found to undergo apoptosis. In serum-free basic fibroblast growth factor-containing culture medium, primary culture cells from fetal mouse neuro-epithelium expressed nestin, and thus might be regarded as NPCs. These NPCs demonstrated apoptosis under electron microscopy and TUNEL assay. Treatment of NPCs with lithium, a specific inhibitor of glycogen synthase kinase 3β (GSK3β), significantly suppressed apoptosis. Activity of pro-apoptotic protease caspase-3 was not detected in either lithium-untreated or -treated NPCs. These findings suggest that lithium may protect NPCs against apoptosis by inhibiting caspase-3-independent apoptotic pathways.