Human germ cell differentiation from fetal- and adult-derived induced pluripotent stem cells

Abstract

Historically, our understanding of molecular genetic aspects of human germ cell development has been limited, at least in part due to inaccessibility of early stages of human development to experimentation. However, the derivation of pluripotent stem cells may provide the necessary human genetic system to study germ cell development. In this study, we compared the potential of human induced pluripotent stem cells (iPSCs), derived from adult and fetal somatic cells to form primordial and meiotic germ cells, relative to human embryonic stem cells. We found that ∼5% of human iPSCs differentiated to primordial germ cells (PGCs) following induction with bone morphogenetic proteins. Furthermore, we observed that PGCs expressed green fluorescent protein from a germ cell-specific reporter and were enriched for the expression of endogenous germ cell-specific proteins and mRNAs. In response to the overexpression of intrinsic regulators, we also observed that iPSCs formed meiotic cells with extensive synaptonemal complexes and post-meiotic haploid cells with a similar pattern of ACROSIN staining as observed in human spermatids. These results indicate that human iPSCs derived from reprogramming of adult somatic cells can form germline cells. This system may provide a useful model for molecular genetic studies of human germline formation and pathology and a novel platform for clinical studies and potential therapeutical applications.

Downregulation of Col1a1 induces differentiation in mouse spermatogonia

“…It is a proteolytic enzyme that hydrolyses the zona pellucida (ZP) of the oocyte in the process of fertilization 29,30 . Acrosin is expressed broadly in 1N spermatid 31 . That is why we could not find Acrosin in the mock spermatogonia.…”

Amniotic fluid stem cell-based models to study the effects of gene mutations and toxicants on male germ cell formation

“…4 Another reason for our limited knowledge on germ cell development in humans is that extrapolation of results obtained from animal models, such as mice, is not really possible (see the discussion in Ref. 5). In no other species, infertility caused by errors in germ cell formation and meiotic missegregation of chromosomes are nearly as common as in humans.…”

“…from reprogramming of somatic cells also have been shown to differentiate into primordial germ cells and even to generate haploid germ cells. 5,[22][23][24] These pioneering studies allowed new important insights into the regulation of germ cell formation in vitro.…”

“…26 An elegant approach allowing flow cytometric isolation of germ cells after bone morphogenetic protein-induced differentiation is prior transfection of the pluripotent stem cells with a reporter system carrying GFP under the VASA promoter. Since spontaneous induction of meiosis is low, overexpression of genes of the DAZ gene family can be performed to induce meiosis for haploid spermatids 5,27 ( Figure 1). Finally, in mice it is possible to test the biological function of so-obtained haploid male gametes either by transplantation into busulfan-mediated sperm-depleted testes to check in vivo differentiation, or by intracytoplasmic injection into recipient oocytes to test whether this supports cleavage [14][15][16] (Figure 1).…”

Gametogenesis in a dish

“…Along with new developments in the iPSC field, current efforts in many labs are aimed at deriving gametes from human iPSCs. In 2011, Panula et al [14] reported their successful derivation of male gametes from human fetal-and adult-derived iPSCs. Meanwhile, Eguizabal et al [15] obtained haploid cells from both cord blood-derived human iPSCs and keratinocyte-derived human iPSCs.…”