| Abstract |
Activation of serotonin (5-hydroxytryptamine; 5-HT) receptors plays a role in adult neurogenesis and differentiation of neural progenitor cells (NPC). Herein, we examined the involvement of 5-HT receptors in the differentiation of mouse induced pluripotent stem (iPS) cells into NPC. To induce embryoid body (EB) formation, mouse iPS cells were cultured on ultralow-attachment dishes. All-trans retinoic acid (ATRA; 1 μmol/L) and/or 5-HT (0.03 or 0.1 μmol/L) was added to the EB cultures for 4 days and then EB plated on gelatin-coated plates were cultured for 7 or 14 days. Immunofluorescence staining revealed that mouse iPS cells expressed both 5-HT2A and 5-HT4 receptors and, to a lesser extent, 5-HT1A receptors. Treatment with 5-HT significantly enhanced the ATRA-induced expression of nestin, a specific marker for NPC, and phosphorylation of cAMP response element-binding protein (CREB). Pretreatment of EB cultures with either 1 μmol/L GR113808 (a selective 5-HT4 receptor antagonist) or 1 μmol/L H89 (a protein kinase (PKA) inhibitor) significantly inhibited these effects of 5-HT. These findings suggest that stimulation of 5-HT4 receptors may enhance ATRA-induced neural differentiation of mouse iPS cells through activation of PKA and CREB.
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