Neuronal cells derived from human induced pluripotent stem cells as a functional tool of melanocortin system

Background The preparation of human neurons derived from human induced pluripotent stem (iPS) cells can serve as a potential tool for evaluating the physiological and pathophysiological properties of human neurons and for drug development. Methods In the present study, the functional activity in neuronal cells differentiated from human iPS cells was observed. Results The differentiated cells expressed mRNAs for classical neuronal markers (microtubule-associated protein 2, β-tubulin III, calbindin 1, synaptophysin and postsynaptic density protein 95) and for subunits of various excitatory and inhibitory transmitters (NR1, NR2A, NR2B, GABA_A α1). Moreover, the differentiated cells expressed neuropeptides and receptors which are predominantly present in the hypothalamus. The expression of mRNA for preopiomelanocortin, agouti-related protein (AgRP), melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R) increased in culture with a peak on Day 30 which subsequently decreased at Day 45. Immunoreactivities for MC3R and MC4R were also observed in cells differentiated from human iPS cells. Application of a potent agonist for MC3R and MC4R, [Nle4, D-Phe7]-α-melanocyte-stimulating hormone, significantly increased intracellular cAMP levels, but this was suppressed by AgRP (83-132) and SHU9119. Conclusions These findings offer the possibility for drug developments using neurons differentiated from normal or disease-associated human iPS cells.