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Feeder cells are usually used in culturing embryonic stem cells (ESCs) to maintain their undifferentiated and pluripotent status. To test whether mouse embryonic stem cells (mESCs) may be a source of feeder cells to support their own growth, 48 fibroblast-like cell lines were isolated from the same mouse embryoid bodies (mEBs) at three phases (10th day, 15th day, 20th day), and five of them, mostly derived from 15th day mEBs, were capable of maintaining mESCs in an undifferentiated and pluripotent state over 10 passages, even up to passage 20. mESCs cultured on the feeder system derived from these five cell lines expressed alkaline phosphatase and specific mESCs markers, including SSEA-1, Oct-4, Nanog, and formed mEBs in vitro and teratomas in vivo. These results suggest that mEB-derived fibroblasts (mEB-dFs) could serve as feeder cells that could sustain the undifferentiated growth and pluripotency of their own mESCs in culture. This study not only provides a novel feeder system for mESCs culture, avoiding a lot of disadvantages of commonly used mouse embryonic fibroblasts as feeder cells, but also indicates that fibroblast-like cells derived from mESCs take on different functions. Investigating the molecular mechanisms of these different functional fibroblast-like cells to act on mESCs will contribute to the understanding of the mechanisms of mESCs self-renewal.

Human embryonic stem (ES) cells have the capacity for self-renewal and are able to differentiate into any cell type. However, obtaining high-efficient neural differentiation from human ES cells remains a challenge. This study describes an improved 4-stage protocol to induce a human ES cell line derived from a Chinese population to differentiate into neural cells. At the first stage, embryonic bodies (EBs) were formed in a chemically-defined neural inducing medium rather than in traditional serum or serum-replacement medium. At the second stage, rosette-like structures were formed. At the third stage, the rosette-like structures were manually selected rather than enzymatically digested to form floating neurospheres. At the fourth stage, the neurospheres were further differentiated into neurons. The results show that, at the second stage, the rate of the formation of rosette-like structures from EBs induced by noggin was 88 ± 6.32%, higher than that of retinoic acid 55 ± 5.27%. Immunocytochemistry staining was used to confirm the neural identity of the cells. These results show a major improvement in obtaining efficient neural differentiation of human ES cells.

In previous studies, progenitor embryoid body-derived (EBD) cells have been derived from human embryonic germ cells. These cells express lineage markers of three primary germ layers, although their potential to produce true fetal cells of various types has yet to be tested. To this end, we have transplanted EBD cells into the fetal sheep liver. We show that these cells respond appropriately to environmental cues and give rise to hepatocytes and well-structured bile ducts. These results suggest that EBD cells are relatively uncommitted early progenitors capable of effective incorporation and differentiation in vivo. The ability to generate functional liver cells makes EBD cells potentially useful for cell therapy.

To solve the problem of immune incompatibility, nuclear transplantation has been envisaged as a means to produce cells or tissues for human autologous transplantation. Here we have derived embryonic stem cells by the transfer of human somatic nuclei into rabbit oocytes. The number of blastocysts that developed from the fused nuclear transfer was comparable among nuclear donors at ages of 5, 42, 52 and 60 years, and nuclear transfer (NT) embryonic stem cells (ntES cells) were subsequently derived from each of the four age groups. These results suggest that human somatic nuclei can form ntES cells independent of the age of the donor. The derived ntES cells are human based on karyotype, isogenicity, in situ hybridization, PCR and immunocytochemistry with probes that distinguish between the various species. The ntES cells maintain the capability of sustained growth in an undifferentiated state, and form embryoid bodies, which, on further induction, give rise to cell types such as neuron and muscle, as well as mixed cell populations that express markers representative of all three germ layers. Thus, ntES cells derived from human somatic cells by NT to rabbit eggs retain phenotypes similar to those of conventional human ES cells, including the ability to undergo multilineage cellular differentiation.

To explore the effect of bone morphogenetic protein (BMP) to activate mesenchymal stem cells of skeletal muscle for rescuing bone marrow failure.The study was performed on lethal rat acute aplastic anemia model induced by combined 5-fluorouracil (5-FU) and busulfan. The rh-BMP-2 was implanted into the thigh muscle of the rats at 3 days before aplastic anemia was induced. In the control group the rats were implanted with agar into the thigh muscle. The blood picture, pathologic changes and the mortality in two groups were observed. At the same time, rh-BMP-2 were implanted into the thigh muscle of normal Kun-min mice for dynamic control observation of the implantation local morphological changes, colony forming units-spleen (CFU-S) and stem cell growth factor (SCF) expression of the stroma cells of ectopic ossicles induced by BMP.At 7 days after BMP implantation in the mice the mesenchymal cells around BMP in muscle proliferated, and appeared in bone marrow to form an ectopic ossicles. The SCF expression of stroma cells in ectopic ossicles were higher than that of self-bone marrow. 56.3% of BMP-treated aplastic rats were survived over 3 months and its hematopoiesis was completely reconstituted and the histo-morphological picture of the spleen and bone marrow were recovered to normal. But in the control group only one of 23 rats was survived, the remainder died of hematopoietic failure.BMP-implantation into the skeletal muscle could rescue the bone marrow hematopoietic failure. The mechanism might be related to the BMP activated auto-mesenchymal cells of skeletal muscles to direct hematopoietic cell differentiation. In our hands it might create a new pathway for utilization of auto-muscle derived mesenchymal cells to reconstitute hematopoiesis.