Differentiation of Human Induced Pluripotent Stem Cells into Male Germ Cells.

Infertility is defined as not being able to become pregnant or to conceive a child after one year or longer of regular unprotected intercourse. Male infertility refers to a male's inability to cause pregnancy that can result from deficiencies in semen quality, sperm concentration, or abnormal sperm function. Till now, there are few effective methods for the treatment of a couple with male infertility. In the past few years, stem cell-based therapy as a promising strategy has emerged for the treatment of male infertility. Human Pluripotent Stem Cells (hPSCs) can self-renew and differentiate into any type of cell. Human Embryonic Stem Cells (hESCs) and induced Pluripotent Stem Cells (hiPSCs) are two pluripotent populations that can proliferate and give rise to ectodermal, mesodermal, endodermal, and germ cell lineages. Both undifferentiated hiPSCs and hESCs are powerful candidates for the treatment of male infertility. Generation of male germ cells from hPSCs can provide new mechanistic insights into the regulation of spermatogenesis and have a great opportunity for families with infertility. Therefore, a robust, reproducible, and low-cost culture method that supports hPSCs differentiation into male germ cells is necessary. However, very few studies have focused on the derivation of sperm-like cells from hiPSCs and the details of hPSCs differentiation into male germ cells have not been fully investigated. Therefore, in this review, we focus on the in vitro differentiation potential of hiPSCs into male germ cells.