Production of stable GFP-expressing neural cells from P19 embryonal carcinoma stem cells.

Murine P19 embryonal carcinoma (EC) cells are convenient to differentiate into all germ layer derivatives. One of the advantages of P19 cells is that the exogenous DNA can be easily inserted into them. Here, at the first part of this study, we generated stable GFP-expressing P19 cells (P19-GFP+). FACS and western-blot analysis confirmed stable expression of GFP in the cells. We previously demonstrated the efficient induction of neuronal differentiation from mouse ES and EC cells by application of a neuroprotective drug, selegiline In the second part of this study selegiline was used to induce differentiation of P19-GFP+ into stable GFP-expressing neuron-like cells. Cresyl violet staining confirmed neuronal morphology of the differentiated cells. Furthermore, real-time PCR and immunoflourescence approved the expression of neuron specific markers. P19-GFP+ cells were able to survive, migrate and integrated into host tissues when transplanted to developing chick embryo CNS. The obtained live GFP-expressing cells can be used as an abundant source of developmentally pluripotent material for transplantation studies, investigating the cellular and molecular aspects of early differentiation.

Neural progenitor NT2N cell lines from teratocarcinoma for transplantation therapy in stroke.

This review article discusses recent progress on the use of teratocarcinoma-derived Ntera2/D1 neuron-like cells (NT2N cells, also called hNT cells) as graft source for cell transplantation in stroke. Laboratory evidence has demonstrated the therapeutic potential of NT2N cells in stroke therapy. Phase I and II clinical trials have shown the cells' feasibility, safety and tolerability profiles in stroke patients. Despite these novel features of NT2N cells, the transplantation regimen remains to be optimized. Moreover, determining the mechanisms underlying the grafts' beneficial effects, specifically demonstrating functional synaptic connections between host brain and NT2N cell grafts, warrants further examination. The major limiting factor for initiating a large clinical trial is the cells' highly potent proliferative property due to their cancerous origin, thereby raising the concern that these cells may revert to a neoplastic state over time after transplantation. To this end, we explored a proof-of-concept "retroviral" strategy to further establish the post-mitotic status of NT2N cells by transfecting these cells with the transcription factor Nurr1, in addition to the standard treatment with retinoic acid and mitotic inhibitors. This new cell line NT2N.Nurr1 displays an expedited neuronal commitment and secretes a high level of the neurotrophic factor glial cell line-derived neurotrophic factor (GDNF), and when transplanted into the rodent stroke brain expressed neuronal phenotype and reduced behavioral impairments which are comparable, if not more robust, than those produced by NT2N cells. Such highly potent neuronal lineage commitment and neurotrophic factor secretory function of NT2.Nurr1 cells make them an appealing graft source for transplantation therapy.

Overexpression of TNNI3K, a cardiac-specific MAP kinase, promotes P19CL6-derived cardiac myogenesis and prevents myocardial infarction-induced injury.

TNNI3K is a new cardiac-specific MAP kinase whose gene is localized to 1p31.1 and that belongs to a tyrosine kinase-like branch in the kinase tree of the human genome. In the present study we investigated the role of TNNI3K in the cardiac myogenesis process and in the repair of ischemic injury. Pluripotent P19CL6 cells with or without transfection by pcDNA6-TNNI3K plasmid were used to induce differentiation into beating cardiomyocytes. TNNI3K promoted the differentiation process, judging from the increasing beating mass and increased number of alpha-actinin-positive cells. TNNI3K improved cardiac function by enhancing beating frequency and increasing the contractile force and epinephrine response of spontaneous action potentials without an increase of the single-cell size. TNNI3K suppressed phosphorylation of cardiac troponin I, annexin-V(+) cells, Bax protein, and p38/JNK-mediated apoptosis. Intramyocardial administration of TNNI3K-overexpressing P19CL6 cells in mice with myocardial infarction improved cardiac performance and attenuated ventricular remodeling compared with injection of wild-type P19CL6 cells. In conclusion, our study clearly indicates that TNNI3K promotes cardiomyogenesis, enhances cardiac performance, and protects the myocardium from ischemic injury by suppressing p38/JNK-mediated apoptosis. Therefore, modulation of TNNI3K activity would be a useful therapeutic approach for ischemic cardiac disease.

Isolation of human embryonic stem cell-derived teratomas for the assessment of pluripotency.

This unit describes protocols on how to assess the developmental potency of human embryonic stem cells (hESCs) by performing xenografting into immunodeficient mice to induce teratoma formation. hESCs can be injected under the testis capsule, or alternatively into the kidney or subcutaneously. Teratomas that develop from grafted hESCs are surgically removed, fixed in formaldehyde, and paraffin embedded. The tissues in the teratoma are analyzed histologically to determine whether the hESCs are pluripotent and form tissues derived from of all three embryonic germ layers (ectoderm, mesoderm, and endoderm). Teratomas can also be fixed in Bouin's or cryosectioned for analysis, and they can be analyzed by immunohistochemistry for tissue markers. Methods for these procedures are included in this unit.