Differentiation of Human Induced Pluripotent Stem Cells Into Testosterone-Producing Leydig-like Cells.

Late-onset hypogonadism (LOH) syndrome, due to a partial lack of testosterone, decreases the quality of life of older men. Testosterone is mainly secreted by Leydig cells in the testes. Leydig cell transplantation is expected to be a promising alternative to conventional testosterone replacement therapy for LOH syndrome. We herein report a simple and robust protocol for directed differentiation of human induced pluripotent stem cells (hiPSCs) into Leydig-like cells by doxycycline-inducible overexpression of NR5A1 and treatment with a combination of 8-bromoadenosine-3',5'-cyclic monophosphate (8-Br-cAMP) and forskolin. The differentiated cells expressed the steroidogenic enzyme genes STAR, CYP11A1, CYP17A1, and HSD3B2 and the specific markers of adult Leydig cells HSD17B3, INSL3, and LHCGR. Furthermore, we confirmed the secretion of functional testosterone from the cells into the culture supernatant by a testosterone-sensitive cell proliferation assay. These findings showed that the hiPSCs were able to be differentiated into Leydig-like cells, supporting the expectation that hiPSC-derived Leydig-like cells can be novel tools for treating LOH syndrome.