Table 1.
Induction of germ cells from human pluripotent stem cells in vitro or in vivo.
| Differentiation Method | Cell Lines Used | Differentiation Stage | Remarks | References | ||||
|---|---|---|---|---|---|---|---|---|
| iPS Cells | ES Cells | PGCs | Meiotic Cells | Haploid Cells | ||||
| EB formation | - | HSF-6(XX) HSF-1(XY) H9(XX) |
- | - | - | Germ cell-like cells expressing VASA, SCP1, SCP3, BOULE, TEKT1, and GDF3 were observed. | Clark et al., 2004 [3] | |
| EB formation | - | NTU1(XX) NTU2(XX) NTU3(N.D.) |
- | - | - | Germ cell-like cells expressing cKit, STELLA, VASA, and GDF9 were observed. | Chen et al., 2006 [4] | |
| Making colonies of fewer than 50 cells | - | HSF-6(XX) H9(XX) |
Yes | - | - | Sertoli-like cells were simultaneously generated in this process. | Bucay et al., 2008 [7] | |
| Monolayer differentiation and FACS enrichment of SSEA1-positive cells | - | H9(XX) hES-NCL1(XX) |
Yes | - | - | PGCs with removal of parental imprints and chromatin modification changes were generated. | Tilgner et al., 2008 [6] | |
| Differentiation on primary human fetal gonadal stromal cells, and isolation of a triple biomarker (cKIT, SSEA1, VASA)—positive cells | hIPS2(XY) hIPS1(XY) |
HSF-6(XX) HSF-1(XY) H9(XX) |
Yes | - | - | PGCs derived from human iPS cells did not initiate imprint erasure as efficiently. | Park et al., 2009 [8] | |
| Overexpression of DAZL, DAZ and BOULE following induction by BMPs | - | HSF-1(XY) HSF-6(XX) H1(XY) H9(XX) |
Yes | Yes | Yes | DAZL functions in PGC formation, whereas DAZ and BOULE promote later stages of meiosis and development of haploid gametes. | Kee et al., 2010 [5] | |
| Overexpression of DAZ, DAZL, and BOULE following induction by BMPs | iPS(IMR90) (XX) iHUF4(XY) |
H9(XX) HSF-1(XY) |
Yes | Yes | Yes | Fetal-derived iPS cell line iPS (IMR90) and adult-derived iPS cell line iHUF4 were generated by lentiviral transfection with OCT3/4, SOX2, KLF4 and c-MYC. | Panula et al., 2011 [10] | |
| Overexpression of VASA and/or DAZL following differentiation on matrigel-coated plates | iPS(IMR90)(XX) iHUF4(XY) |
iHUF3(XX) iHUF4(XY) |
Yes | Yes | Yes | The same iPS cell lines described in Panula et al. were used. | Medrano et al., 2011 [9] | |
| Two step protocol: Culture in bFGF-depleted ES cell media, subsequently, RA added; Sorted cells are cultured with FRSK, rLIF, bFGF, and R115866 | KiPS1(XY) KiPS2(XY) KiPS3(XY) KiPS4(XX) CBiPS1(XY) CBiPS2(XY) CBiPS3(XX) CBiPS4(XY) CBiPS5(XX) |
HS306(XX) ES[6](XY) |
- | Yes | Yes | iPS cells of different origin (keratinocytes and cord blood) were generated with a different number (2–4) of transcription factors. | Eguizabal et al., 2011 [13] | |
| Direct differentiation using mouse SSC culture conditions | H1(XY) | HFF1(XY) | - | Yes | Yes | iPS cells derived from male foreskin fibroblasts were used. | Easley et al., 2012 [12] | |
| 1. Differentiation into PGCs with BMPs, RA, and hrLIF. 2. Induction of gonocytes by transplanting iPS cells directly into murine seminiferous tubules in vivo | iAZF1(XY) iAZF2(XY) iAZFΔbc(XY) iAZFΔc(XY) iAZFΔa(XY) |
H1(XY) | Yes | - | - | iPS cells derived from dermal fibroblasts of males with intact Y chromosome (iAZF) and Y chromosome deletions (iAZFΔ) were used. Gonocytes expressing VASA, STELLA, UTF1, PLZF, and DAZ were induced. | Ramanthal et al., 2014 [11] | |
PGCs: primordial germ cells; EB: embryoid body; BMPs: bone morphogenetic proteins; bFGF: basic fibroblast growth factor; FRSK: Forskolin; RA: retinoic acid; hrLIF: human recombinant leukemia inhibitory factor; SSC: spermatogonial stem cell.