BMP4 can generate primordial germ cells from bone‐marrow‐derived pluripotent stem cells

Abstract

Evidence of germ cell derivation from embryonic and somatic stem cells provides an in vitro model for the study of germ cell development, associated epigenetic modification and mammalian gametogenesis. More importantly, in vitro derived gametes also represent a potential strategy for treating infertility. In mammals, male and female gametes, oocyte and sperm, are derived from a specific cell population, PGCs (primordial germ cells) that segregate early in embryogenesis. We have isolated pluripotent SSEA-1+ (stage-specific embryonic antigen-1+) cells from mice bone marrow using a MACS (magnetic-activated cell sorting) system. SSEA-1+ cells were directly separated from the suspension of MMCs (murine mononuclear cells) harvested from bone marrow of 2-4-week-old mice. Flow-cytometry assay immediately after sorting and culturing under undifferentiated condition showed 55±7% and 87±4% purity respectively. RT-PCR (reverse transcription-PCR) analysis after differentiation of SSEA-1+ cells into derivations of three germ layers showed the pluripotency properties of isolated cells. SSEA-1+ cells were induced to differentiate along germ cell lineage by adding BMP4 (bone morphogenic factor-4) to the medium. Regarding the expression of germ cell markers (PGCs, male and female germ cell lineage), it was found that adding exogenous BMP4 to culture medium could differentiate pluripotent SSEA-1+ cells isolated from an adult tissue into gamete precursors, PGCs. Differentiated cells expressed specific molecular markers of PGCs, including Oct4, fragilis, Stella and Mvh (mouse vasa homologue). Therefore BMP4 is insufficient to induce SSEA-1+ cells derived from PGCs to develop further into late germ cells in vitro.

Potential Spermatogenesis Recovery with Bone Marrow Mesenchymal Stem Cells in an Azoospermic Rat Model

“…Genetically-modified somatic cells or stem cells have been intensively investigated [8,9,10,11,12,13,14,15]. Although the induced stem cells express functional genes and act as sperm cells, the risk and safety of using these cells have been of concern.…”

Expression of the erythropoietin receptor by germline-derived cells - further support for a potential developmental link between the germline and hematopoiesis

“…Furthermore, the presence of early-development stem cells with germline markers in BM that are able to differentiate along the germline lineage has already been demonstrated by several investigators. For example, murine BM SSEA-1 + cells stimulated by bone morphogenic factor 4 may differentiate Oct-4 + Stella + Mvh + cells into gamete precursors [50]. Similarly, a population of Oct-4 + Mvh + Dazl + Stella + cells present in murine BM has been reported to affect the recurrence of oogenesis in mice sterilized by chemotherapy [51,52], and Oct-4 + Mvh + Stella + cells isolated as Stra8–GFP cells from BM of Stra8–GFP transgenic mice express several molecular markers of spermatogonial stem cells and spermatogonia [6].…”

Novel view of the adult stem cell compartment – of germline and parental imprinting

“…These cells have been described by different names, and most likely some of them are overlapping stem cell populations at different levels of tissue specification [67][68][69][70][71][72][73].…”

“…In Table 1, reports on early-development stem cells isolated from adult tissues that express germline markers are listed [67][68][69][70][71][72][73], but their relationship to VSELs requires further study. Nevertheless, these observations support the concept that developmentally early stem cells from embryogenesis could be deposited in adult tissues and that there exists in the stem cell compartment a stem cell continuum beginning with embryonic development and extending into adulthood [24].…”