Neurogenin 3 is regulated by neurotrophic tyrosine kinase receptor type 2 (TRKB) signaling in the adult human exocrine pancreas.

Background: Reports of exocrine-to-endocrine reprogramming through expression or stabilization of the transcription factor neurogenin 3 (NGN3) have generated renewed interest in harnessing pancreatic plasticity for therapeutic applications. NGN3 is expressed by a population of endocrine progenitor cells that give rise exclusively to hormone-secreting cells within pancreatic islets and is necessary and sufficient for endocrine differentiation during development. In the adult human pancreas, NGN3 is expressed by dedifferentiating exocrine cells with a phenotype resembling endocrine progenitor cells and the capacity for endocrine differentiation in vitro.

Neurogenin 3 Expressing Cells in the Human Exocrine Pancreas Have the Capacity for Endocrine Cell Fate.

Neurogenin 3 (NGN3) is necessary and sufficient for endocrine differentiation during pancreatic development and is expressed by a population of progenitor cells that give rise exclusively to hormone-secreting cells within islets. NGN3 protein can be detected in the adult rodent pancreas only following certain types of injury, when it is transiently expressed by exocrine cells undergoing reprogramming to an endocrine cell fate. Here, NGN3 protein can be detected in 2% of acinar and duct cells in living biopsies of histologically normal adult human pancreata and 10% in cadaveric biopsies of organ donor pancreata.

Chondroitin sulfate proteoglycans inhibit oligodendrocyte myelination through PTPσ.

CNS damage often results in demyelination of spared axons due to oligodendroglial cell death and dysfunction near the injury site. Although new oligodendroglia are generated following CNS injury and disease, the process of remyelination is typically incomplete resulting in long-term functional deficits. Chondroitin sulfate proteoglycans (CSPGs) are upregulated in CNS grey and white matter following injury and disease and are a major component of the inhibitory scar that suppresses axon regeneration.

Use of perfluorocarbon nanoparticles for non-invasive multimodal cell tracking of human pancreatic islets.

In vivo imaging of engraftment and immunorejection of transplanted islets is critical for further clinical development, with (1)H MR imaging of superparamagnetic iron oxide-labeled cells being the current premier modality. Using perfluorocarbon nanoparticles, we present here a strategy for non-invasive imaging of cells using other modalities. To this end, human cadaveric islets were labeled with rhodamine-perfluorooctylbromide (PFOB) nanoparticles, rhodamine-perfluoropolyether (PFPE) nanoparticles or Feridex as control and tested in vitro for cell viability and c-peptide secretion for 1 week.

OCT3/4 regulates transcription of histone deacetylase 4 (Hdac4) in mouse embryonic stem cells.

OCT3/4 is a POU domain transcription factor that is critical for maintenance of pluripotency and self-renewal by embryonic stem (ES) cells and cells of the early mammalian embryo. It has been demonstrated to bind and regulate a number of genes, often in conjunction with the transcription factors SOX2 and NANOG. In an effort to further understand this regulatory network, chromatin immunoprecipitation was used to prepare a library of DNA segments specifically bound by OCT3/4 in undifferentiated mouse ES (mES) cell chromatin.

Imprinting status of Galpha(s), NESP55, and XLalphas in cell cultures derived from human embryonic germ cells: GNAS imprinting in human embryonic germ cells.

GNAS is a complex gene that through use of alternative first exons encodes signaling proteins Galpha(s) and XLalphas plus neurosecretory protein NESP55. Tissue-specific expression of these proteins is regulated through reciprocal genomic imprinting in fully differentiated and developed tissue. Mutations in GNAS account for several human disorders, including McCune-Albright syndrome and Albright hereditary osteodystrophy, and further knowledge of GNAS imprinting may provide insights into variable phenotypes of these disorders.

Proliferation and pluripotency of human embryonic stem cells maintained on type I collagen.

Human embryonic stem cells (hESC) require a balance of growth factors and signaling molecules to proliferate and retain pluripotency. Conditioned medium (CM) from a human embryonic germ-cell-derived cell culture, SDEC, was observed to support the growth of hESC on type I collagen (COL I) and on Matrigel (MAT) biomatricies. After 1 month, the population doubling of hESC grown in SDEC CM on COL I was equivalent to that of hESC grown in mouse embryonic fibroblast (MEF) CM on MAT.

Stem cells and the liver: clinical applications in transplantation.

ESLD affects millions of Americans, and HCV is a worldwide pandemic. Unfortunately, the ability to study liver disease and novel therapeutics experimentally in the laboratory is limited by an ongoing lack of small animal models. The development of rodents with livers chimeric for human hepatocytes may improve this situation.

Physical transfer of membrane and cytoplasmic components as a general mechanism of cell-cell communication.

Recent evidence from different research areas has revealed a novel mechanism of cell-cell communication by spontaneous intercellular transfer of cellular components (ICT). Here we studied this phenomenon by co-culturing different cells that contain distinct levels of proteins or markers for the plasma membrane or cytoplasm. We found that a variety of transmembrane proteins are transferable between multiple cell types.

Cells derived from human umbilical cord blood support the long-term growth of undifferentiated human embryonic stem cells.

Various types of human cells have been tested as feeder cells for the undifferentiated growth of human embryonic stem cells (hESCs) in vitro. We report here the successful culture of two hESC lines (H1 and H9) on human umbilical cord blood (UCB)-derived fibroblast-like cells. These cells permit the long-term continuous growth of undifferentiated and pluripotent hESCs.

Generation of humanized animal livers using embryoid body-derived stem cell transplant.

Objective: Animal organs engineered to be chimeric for human cells could contribute significantly to the field of transplantation, including studies of human-specific diseases such as hepatitis-C, as treatment for in-born errors of metabolism, and for development of a renewable source of transplantable organs via modified xenotransplantation. We sought to use human embryoid body-derived stem cells (EBDs) to populate livers in animals for applications in transplant surgery.

Methods: SCID mice and rats underwent liver injury with carbon tetrachloride exposure or partial hepatectomy.

Embryonic germ cells are capable of adipogenic differentiation in vitro and in vivo.

There is an extensive clinical need for soft tissue filler materials, such as adipose tissue, for plastic and reconstructive surgery. Due to limitations with autologous adipose transplantation, engineered adipose tissue provides a potential alternative therapy. Embryonic germ cells form embryoid bodies and subsequent embryoid body-derived (EBD) cells have the ability to differentiate toward multiple tissue types.

SOX17 directly activates Zfp202 transcription during in vitro endoderm differentiation.

SOX17 is a SRY-related high-mobility group (HMG) box transcription factor that is necessary for endoderm formation in multiple species. Despite its essential function during endoderm formation and differentiation, few direct targets of SOX17 are known. To identify targets of SOX17, we isolated SOX17 binding sites with a chromatin immunoprecipitation (ChIP)-cloning screen.

Glucose responsive insulin production from human embryonic germ (EG) cell derivatives.

Type 1 diabetes mellitus subjects millions to a daily burden of disease management, life threatening hypoglycemia and long-term complications such as retinopathy, nephropathy, heart disease, and stroke. Cell transplantation therapies providing a glucose-regulated supply of insulin have been implemented clinically, but are limited by safety, efficacy and supply considerations. Stem cells promise a plentiful and flexible source of cells for transplantation therapies.

Pluripotent stem cells from germ cells.

To date, stem cells have been derived from three sources of germ cells. These include embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and multipotent germ line stem cells (GSCs). EGCs are derived from primordial germ cells that arise in the late embryonic and early fetal period of development.

Stem cell profiling by nuclear magnetic resonance spectroscopy.

The classification of embryonic and adult stem cells, including their derivatives, is still limited, and often these cells are best defined by their functional properties. Recent gene array studies have yielded contradictory results. Also, very little is known about the metabolic properties of these exciting cells.

Transplanted human embryonic germ cell-derived neural stem cells replace neurons and oligodendrocytes in the forebrain of neonatal mice with excitotoxic brain damage.

Stem cell therapy is a hope for the treatment of some childhood neurological disorders. We examined whether human neural stem cells (hNSCs) replace lost cells in a newborn mouse model of brain damage. Excitotoxic lesions were made in neonatal mouse forebrain with the N-methyl-D-aspartate (NMDA) receptor agonist quinolinic acid (QA).

Musculoskeletal differentiation of cells derived from human embryonic germ cells.

Stem cells have the potential to significantly improve cell and tissue regeneration therapies, but little is understood about how to control their behavior. We investigated the potential differentiation capability of cells derived from human embryonic germ (EG) cells into musculoskeletal lineages by providing a three-dimensional environment with increased cell-cell contact and growth factors. Cells were clustered into pellets to mimic the mesenchyme condensation process during limb development.

Cell therapies for type 1 diabetes mellitus.

Type 1 diabetes is caused by autoimmune destruction of pancreatic beta-cells and is characterised by absolute insulin insufficiency. The monocellular nature of this disease and endocrine action of insulin make this disease an excellent candidate for cellular therapy. Furthermore, precedent for cellular therapies has been set by successful cadaveric whole pancreas and islet transplantation.

Human embryonic germ cell derivatives facilitate motor recovery of rats with diffuse motor neuron injury.

We have investigated the potential of human pluripotent cells to restore function in rats paralyzed with a virus-induced motor neuronopathy. Cells derived from embryonic germ cells, termed embryoid body-derived (EBD) cells, introduced into the CSF were distributed extensively over the rostrocaudal length of the spinal cord and migrated into the spinal cord parenchyma in paralyzed, but not uninjured, animals. Some of the transplanted human cells expressed the neuroglial progenitor marker nestin, whereas others expressed immunohistochemical markers characteristic of astrocytes or mature neurons.

Prolactin gene expression in human ovarian follicular cells.

Objective: To investigate prolactin gene expression in human ovarian follicular cells.

Design: RNA was isolated from follicular cells obtained at the time of transvaginal oocyte retrieval from patients after controlled ovarian hyperstimulation. The RNA was subjected to reverse transcription and polymerase chain reaction (RT-PCR) using prolactin-specific primers.

Glucose-responsive insulin-producing cells from stem cells.

Recent success with immunosuppression following islet cell transplantation offers hope that a cell transplantation treatment for type 1 (juvenile) diabetes may be possible if sufficient quantities of safe and effective cells can be produced. For the treatment of type 1 diabetes, the two therapeutically essential functions are the ability to monitor blood glucose levels and the production of corresponding and sufficient levels of mature insulin to maintain glycemic control. Stem cells can replicate themselves and produce cells that take on more specialized functions.

Monoallelic expression and methylation of imprinted genes in human and mouse embryonic germ cell lineages.

Imprinting is an epigenetic modification leading to monoallelic expression of some genes, and disrupted imprinting is believed to be a barrier to human stem cell transplantation, based on studies that suggest that epigenetic marks are unstable in mouse embryonic germ (EG) and embryonic stem (ES) cells. However, stem cell imprinting has not previously been examined directly in humans. We found that three imprinted genes, TSSC5, H19, and SNRPN, show monoallelic expression in in vitro differentiated human EG-derived cells, and a fourth gene, IGF2, shows partially relaxed imprinting at a ratio from 4:1 to 5:1, comparable to that found in normal somatic cells.