Biomedical subjects

Shi-Jiang Lu

Publications and source records attributed to Shi-Jiang Lu.

8 recordsLinked to original sources

PubMed2006

Human embryonic stem cell lines derived from single blastomeres.

The derivation of human embryonic stem (hES) cells currently requires the destruction of ex utero embryos. A previous study in mice indicates that it might be possible to generate embryonic stem (ES) cells using a single-cell biopsy similar to that used in preimplantation genetic diagnosis (PGD), which does not interfere with the embryo's developmental potential. By growing the single blastomere overnight, the resulting cells could be used for both genetic testing and stem cell derivation without affecting the clinical outcome of the procedure. Here we report a series of ten separate experiments demonstrating that hES cells can be derived from single blastomeres. In this proof-of-principle study, multiple biopsies were taken from each embryo using micromanipulation techniques and none of the biopsied embryos were allowed to develop in culture. Nineteen ES-cell-like outgrowths and two stable hES cell lines were obtained. The latter hES cell lines maintained undifferentiated proliferation for more than eight months, and showed normal karyotype and expression of markers of pluripotency, including Oct-4, SSEA-3, SSEA-4, TRA-1-60, TRA-1-81, nanog and alkaline phosphatase. These cells retained the potential to form derivatives of all three embryonic germ layers both in vitro and in teratomas. The ability to create new stem cell lines and therapies without destroying embryos would address the ethical concerns of many, and allow the generation of matched tissue for children and siblings born from transferred PGD embryos.

Blastomeres↗

PubMed2006

Hematopoietic cells from primate embryonic stem cells.

Embryonic stem (ES) cells, derived from early stage embryos, are pluripotent precursors of all of the tissues and organs of the body. ES cells from the mouse have been shown to undergo differentiation in vitro to form a variety of different cell types, including the differentiated progeny of hematopoietic precursors. These hematopoietic cells, however, exhibit numerous differences from those of human cells, and it has become increasingly clear that mouse ES cell differentiation has significant limitations as a model of human developmental biology. The more recent isolation and characterization of nonhuman primate ES cell lines have made available an experimental model with characteristics considerably more close to human biology. We have developed experimental conditions that promote efficient differentiation of these cells to produce progeny cells with considerable similarity to hematopoietic precursors harvested from bone marrow of adult animals.

Animals↗

PubMed2005

Embryonic and extraembryonic stem cell lines derived from single mouse blastomeres.

The most basic objection to human embryonic stem (ES) cell research is rooted in the fact that ES cell derivation deprives embryos of any further potential to develop into a complete human being. ES cell lines are conventionally isolated from the inner cell mass of blastocysts and, in a few instances, from cleavage stage embryos. So far, there have been no reports in the literature of stem cell lines derived using an approach that does not require embryo destruction. Here we report an alternative method of establishing ES cell lines-using a technique of single-cell embryo biopsy similar to that used in pre-implantation genetic diagnosis of genetic defects-that does not interfere with the developmental potential of embryos. Five putative ES and seven trophoblast stem (TS) cell lines were produced from single blastomeres, which maintained normal karyotype and markers of pluripotency or TS cells for up to more than 50 passages. The ES cells differentiated into derivatives of all three germ layers in vitro and in teratomas, and showed germ line transmission. Single-blastomere-biopsied embryos developed to term without a reduction in their developmental capacity. The ability to generate human ES cells without the destruction of ex utero embryos would reduce or eliminate the ethical concerns of many.

Animals↗

PubMed2004

CD34+CD38- hematopoietic precursors derived from human embryonic stem cells exhibit an embryonic gene expression pattern.

Gene expression patterns of CD34(+)CD38(-) cells derived from human embryonic stem cells (ESCs) were compared with those of cells isolated from adult human bone marrow (BM) using microarrays; 1692 and 1494 genes were expressed at levels at least 3-fold above background in cells from BM and ESCs, respectively. Of these, 494 showed similar levels of expression in cells from both sources, 791 genes were overexpressed in cells from BM (BM versus ESCs, at least 2-fold), and 803 genes were preferentially expressed in cells from ESCs (ESCs versus BM, at least 2-fold). The message of the flt-3 gene was markedly decreased in cells from ESCs, whereas there was substantial flt-3 expression in cells from BM. High levels of embryonic epsilon-globin expression were observed-but no adult beta-globin message-in CD34(+)CD38(-) cells from ESCs, whereas high levels of beta-globin expression-but no embryonic epsilon-globin message-could be detected in cells from BM. Furthermore, high levels of major histocompatibility complex (MHC) gene expression were demonstrated in cells from BM but very low levels of MHC message in corresponding cells from ESCs. These observations demonstrate that CD34(+)CD38(-) cells derived from ESCs correspond consistently to an early developmental stage at which the yolk sac and fetal liver are the primary sites of hematopoiesis.

ADP-ribosyl Cyclase↗

PubMed2003

Identification of genes preferentially expressed in mammary epithelial cells of Copenhagen rat using subtractive hybridization and microarrays.

Rats, like humans, vary considerably in susceptibility for mammary cancer development among different strains. The Copenhagen (Cop) rat is extremely resistant to mammary cancer development induced by a variety of carcinogens. Multiple genetic loci have been linked to the resistant phenotype, but the genes have yet to be cloned and the mechanisms underlying the resistance still remain unknown. Transplantation experiments, however, have demonstrated that these genes act only in the epithelial cells of mammary parenchyma; they do not act systemically. In the present study, we analyzed genes differentially expressed in mammary epithelial cells obtained from pubescent female Cop and susceptible Buffalo (Buf) rats, using PCR-based suppressive subtractive hybridization and cDNA microarray approaches. Our results showed a high degree of similarity in the expression profiles of about 4000 genes between Cop and Buf rats, with a few exceptions. We found that the interleukin-2 receptor alpha (IL-2Ralpha) chain gene and claudin-6 gene were preferentially expressed in mammary epithelial cells purified from Cop rats. We further demonstrated that IL-2Ralpha message was undetectable in two rat mammary cancer cell lines and in two human breast cancer cell lines. The level of claudin-6 mRNA was undetectable in two rat mammary cancer cell lines and was lower in two human breast cancer cell lines and one breast cancer sample than that in normal breast tissues. These results suggest that IL-2Ralpha and claudin-6 may function as tumor suppressors, particularly for breast cancer. However, this possibility needs further investigation.

Amino Acid Sequence↗

PubMed2002

Resistance to mammary carcinogenesis in Copenhagen rats: potential roles of vascular endothelial growth factor and mast cells.

The Copenhagen (COP) rat is extremely resistant to mammary cancer induction by carcinogens. Multiple genetic loci have been linked to the resistant phenotype, but the mechanisms underlying the resistance still remain unknown. Evidence has shown that the acquisition of angiogenic capacity is critical for tumor development. We, therefore, decided to investigate whether administration of angiogenic factor would enhance mammary carcinogenesis in the COP rat. Vascular endothelial growth factor (VEGF) was administered in a sustained releasing formula to pubescent female COP rats 2 weeks after N-nitroso-N-methylurea (NMU) treatment. Six months after NMU exposure, we found no difference in mammary tumor incidence between VEGF treated animals and controls. Analysis of VEGF expression, however, revealed different expression patterns in mammary epithelial cells of various origins. Mammary epithelial cells from pubescent susceptible Buffalo (BUF) and COP rats expressed substantial levels of VEGF messages, whereas cells prepared from 230-day-old rats showed negligible levels of VEGF mRNA. We also demonstrated that mammary epithelial cells from tumors developed in susceptible BUF rats expressed VEGF, whereas VEGF messages were barely detectable in tumors induced in COP rats. Furthermore, enlargement of the intramammary lymph nodes with prominent mast cells was observed in NMU treated COP rats, but not in NMU treated BUF rats. These results suggest that down regulation of VEGF expression is insufficient for resistance to mammary carcinogenesis, and that enhanced immune response, as evidenced by intramammary lymph node enlargement with mast cell accumulation, may also play a role in conferring resistance in the COP rat.

Animals↗

PubMed2002

Comparative gene expression in hematopoietic progenitor cells derived from embryonic stem cells.

OBJECTIVE: The aim of this study was to characterize at the molecular level the hematopoietic progenitor cells derived from rhesus monkey embryonic stem (ES) cell differentiation. MATERIALS AND METHODS: We purified CD34(+) and CD34(+)CD38(-) cells from rhesus monkey ES cell cultures and examined the expression of a variety of genes associated with hematopoietic development, by semiquantitative polymerase chain reaction analysis. For comparison, we examined cell preparations from fresh or cultured rhesus monkey bone marrow (BM) and from mouse ES cells and BM. RESULTS: We observed a high degree of similarity in the expression patterns of these genes, with only a few exceptions. Most notably, the message of the flt3 gene was undetectable in rhesus monkey ES cell-derived CD34(+) and CD34(+)CD38(-) cells, whereas substantial flt3 expression was observed in the corresponding cells from fresh BM and in CD34(+) cells from cultured BM. The integrin alphaL and interleukin-6 (IL-6) receptor genes also were expressed in CD34(+)CD38(-) cells from BM, but there was little or no expression of these genes in CD34(+)CD38(-) cells derived from ES cells. Parallel analyses, using CD34(+)Lin(-) cells derived from murine ES cell cultures, showed no apparent expression of flt3, integrin alphaL, or IL-6 receptor, whereas corresponding cell preparations isolated from mouse BM expressed high levels of all of these genes. CONCLUSIONS: ES cell-derived hematopoietic progenitors, both from the rhesus monkey and from the mouse, exhibited the same alterations in gene expression compared with BM-derived cells from these animals. These observations could reflect the presence of different subpopulations in the cell fractions that were compared, or they may represent altered biologic properties of ES cell-derived hematopoietic stem cells.

ADP-ribosyl Cyclase↗

PubMed2002

Hematopoietic progenitor cells derived from embryonic stem cells: analysis of gene expression.

Rhesus monkey embryonic stem (ES) cells undergo differentiation in vitro to generate hematopoietic progenitor cells. Our previous studies demonstrated a high degree of similarity in the expression of genes associated with hematopoietic differentiation, homing, and engraftment in CD34(+) and CD34(+)CD38(-) cells from rhesus monkey ES cells and from fresh or cultured bone marrow (BM). In the present study, we compared the expression patterns of cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors (CDIs) in these cells. The expression of genes for cyclins, CDKs, and CDIs was similar among the hematopoietic progenitor cells of different origins, with only minor differences. Differentially expressed genes were also analyzed in CD34(+) lineage-negative cells derived from mouse ES cells and from BM. No difference or totally divergent results were obtained with the latter system, suggesting that this variation may be species specific. We observed, however, that CD34(+) and CD34(+)CD38(-) cells derived from ES cells expressed embryonic epsilon and zeta as well as alpha, beta, and gamma globin genes, whereas no expression of embryonic globins could be detected in the cell preparations from BM. Moreover, erythroblast-enriched CD34(-) cells derived from 4- or 5-week ES cell differentiation cultures also expressed embryonic, fetal, and adult globin genes, with greater beta gene expression, but otherwise were identical to those of the more primitive CD34(+) cells derived from 2-week ES cultures. These latter observations may reflect the presence of heterogeneous cell populations within the cell fractions that were compared, or they may represent variability among ES-cell-derived hematopoietic stem cells.

ATP Binding Cassette Transporter, Subfamily G, Mem↗