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Selected AbstractsExpression of functional NR1/NR2B-type NMDA receptors in neuronally differentiated SK-N-SH human cell lineEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2002Marina Pizzi Abstract The present study demonstrates that human SK-N-SH neuroblastoma cells, differentiated by retinoic acid (RA), express functional NMDA receptors and become vulnerable to glutamate toxicity. During exposure to RA, SK-N-SH cells switched from non-neuronal to neuronal phenotype by showing antigenic changes typical of postmitotic neurons together with markers specific for cholinergic cells. Neuronally differentiated cells displayed positive immunoreactivity to the vesicular acetylcholine transporter and active acetylcholine release in response to depolarizing stimuli. The differentiation correlated with the expression of NMDA receptors. RT-PCR and immunoblotting analysis identified NMDA receptor subunits NR1 and NR2B, in RA-differentiated cultures. The NR1 protein immunolocalized to the neuronal cell population and assembled with the NR2B subunit to form functional N -methyl- d -aspartate (NMDA) receptors. Glutamate or NMDA application, concentration-dependently increased the intracellular Ca2+ levels and acetylcholine release in differentiated cultures, but not in undifferentiated SK-N-SH cells. Moreover, differentiated cultures became vulnerable to NMDA receptor-mediated excitotoxicity. The glutamate effects were enhanced by glycine application and were prevented by the NMDA receptor blocker MK 801, as well as by the NR2B selective antagonist ifenprodil. These data suggest that SK-N-SH cells differentiated by brief treatment with RA may represent an unlimited source of neuron-like cells suitable for studying molecular events associated with activation of human NR1/NR2B receptors. [source] Transplantation of human embryonic stem cell-derived endothelial cells for vascular diseasesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2009Zongjin Li Abstract Using endothelial cells for therapeutic angiogenesis/vasculogenesis of ischemia diseases has led to exploring human embryonic stem cells (hESCs) as a potentially unlimited source for endothelial progenitor cells. With their capacity for self-renewal and pluripotency, hESCs and their derived endothelial cells (hESC-ECs) may be more advantageous than other endothelial cells obtained from diseased populations. However, hESC-ECs' poor differentiation efficiency and poorly characterized in vivo function after transplantation present significant challenges for their future clinical application. This review will focus on the differentiation pathways of hESCs and their therapeutic potential for vascular diseases, as well as the monitoring of transplanted cells' fate via molecular imaging. Finally, cell enhancement strategies to improve the engraftment efficiency of hESC-ECs will be discussed. J. Cell. Biochem. 106: 194,199, 2009. © 2008 Wiley-Liss, Inc. [source] Establishment and characterization of immortalized human gingival keratinocyte cell linesJOURNAL OF PERIODONTAL RESEARCH, Issue 6 2008S. Gröger Background and Objective:, Primary human keratinocytes are used to analyze the properties of the oral epithelium and the early stages of oral bacterial infections. In vitro, these cells are characterized by their short life span and restricted availability. Approaches for culturing these cells will end after approximately 6,10 passages as a result of entry into apoptosis. For this reason, it is important to generate cell lines suitable for obtaining an unlimited source of cells. Therefore, the aim of the present study was to generate gingival keratinocyte cell lines and to compare their in vitro behaviour with those of primary human gingival keratinocytes. Material and Methods:, Primary human gingival keratinocytes were immortalized with a combination of the human papilloma virus onkoproteins E6 and E7. The pattern of the cytokeratins, involucrin and filaggrin was investigated by intracellular staining using flow cytometry. This method allows quantitative analysis of the expression of a variety of intracellular or extracellular markers. Results:, The immortalized cell lines showed many morphological similarities, expressing a cytokeratin pattern that is comparable with that of primary gingival keratinocytes. Furthermore, they developed transepithelial electrical resistance, which is a marker for the generation of tight junctions. These results indicate that the cells might be able to act as an epithelial barrier, reflecting the reaction of primary human cells. Conclusion:, The establishment of a continuous line of human gingival epithelial cells with functional characteristics of the epithelial barrier provides a valuable in vitro model for using to study the early steps of gingival/periodontal infections. [source] Liver fibrosis: searching for cell model answersLIVER INTERNATIONAL, Issue 4 2007Ma. Concepción Gutiérrez-Ruiz Abstract Hepatic stellate cells (HSC) are the principal fibrogenic cell type in the liver. Progress in understanding the cellular and molecular basis for the development and progression of liver fibrosis could be possible by the development of methods to isolate HSC from rodents and human liver. Growth of stellate cells on plastic led to a phenotypic response known as activation, which paralleled closely the response of these cells to injury in vivo. Actually, much of the current knowledge of stellate cell behaviour has been gained through primary culture studies, particularly from rats. Also, different laboratories that have established hepatic stellate cell lines from rats and humans have provided a stable and unlimited source of cells that express specific functions, making them suitable for culture-based studies of hepatic fibrosis. From these in vitro models grew a large body of information characterizing stellate cell activation, cytokine signalling, intracellular pathways regulating liver fibrogenesis, production of extracellular matrix proteins and development of antifibrotic drugs. [source] | |||||||||||||