iPSC-derived neurons as a tool for probing molecular pharmacology of antipsychotic action

ABSTRACT Background Induced pluripotent stem cell derived neurons (iPSC-Neurons) provide a potential way to investigate molecular mechanisms of psychotropic drug action in human neurons. Until now such studies have relied on animal models or artificial expression systems in transfected cells. Methods Induced pluripotent stem cells were subjected to a dual SMAD inhibition differentiation protocol. Resulting neurons were examined using qPCR, immunocytochemistry, viral transduction, and calcium imaging. Results Here we report the presence of target receptors for antipsychotic drugs in human iPSC-neurons. A cortical neuronal differentiation protocol resulted in cells that expressed D2, 5HT2A, and other target receptors. Moreover, stimulation with glutamate, dopamine, or the 5HT2A agonist DOI evoked calcium transients. We analyzed single cell responses, and found cells with signature response profiles to these ligands. In addition, pre-incubation of iPSC-neurons with clozapine altered the proportion of cells that responded to glutamate or DOI in a subpopulation of neurons. Conclusions Our results support the use of iPSC-neuron single cell pharmacology for studying how psychotropic medications modulate neuronal responses. Because these cells can be derived directly from patients, results derived from using iPSC-neurons have immediate relevance for personalized medicine. Significance Statement The current study examines the feasibility of using induced pluripotent stem cells from patients to generate neurons and study psychopharmacology. This article is broadly intended to inform the readership on the key points of iPSC-derived neurons as a system and how it can be used to understand antipsychotic pharmacology for potential clinical application. The specific advances include 1) demonstrating the presence of receptors targeted by antipsychotics on iPSC-derived neurons; 2) Using single cell analysis to identify human neurons with distinct responses to receptor modulation; and 3) Demonstrating that clozapine modulates glutamatergic and serotonergic responses in distinct human neuronal populations.