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18 results on '"Gomes, Ignatius"'

10. Summary of the First International Gastrointestinal Eosinophil Research Symposium

Author

Liacouras, Chris A, primary, Bonis, Peter, additional, Putnam, Phil E, additional, Straumann, Alex, additional, Ruchelli, Eduardo, additional, Gupta, Sandeep K, additional, Lee, James J, additional, Hogan, Simon P, additional, Wershil, Barry K, additional, Rothenberg, Marc E, additional, Ackerman, Steven J, additional, Gomes, Ignatius, additional, Murch, Simon, additional, Mishra, Anil, additional, and Furuta, Glenn T, additional

Published
2007
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17. Hemangioblastic Derivatives from Human Induced Pluripotent Stem Cells Exhibit Limited Expansion and Early Senescence.

Author

QIANG FENG, SHI-JIANG LU, KLIMANSKAYA, IRINA, GOMES, IGNATIUS, DOHOON KIM, YOUNG CHUNG, HONIG, GEORGE R., KWANG-SOO KIM, and LANZA, ROBERT

Subjects
EMBRYONIC stem cells, APOPTOSIS, CELL death, HUMAN cloning, STEM cells
Abstract

Human induced pluripotent stem cells (hiPSC) have been shown to differentiate into a variety of replacement cell types. Detailed evaluation and comparison with their human embryonic stem cell (hESC) counterparts is critical for assessment of their therapeutic potential. Using established methods, we demonstrate here that hiPSCs are capable of generating hemangioblasts/blast cells (BCs), endothelial cells, and hematopoietic cells with phenotypic and morphologic characteristics similar to those derived from hESCs, but with a dramatic decreased efficiency. Furthermore, in distinct contrast with the hESC derivatives, functional differences were observed in BCs derived from hiPSCs, including significantly increased apoptosis, severely limited growth and expansion capability, and a substantially decreased hematopoietic colony-forming capability. After further differentiation into erythroid cells. >l,000-fold difference in expansion capability was observed in hiPSC-BCs versus hESC-BCs. Although endothelial cells derived from hiPSCs were capable of taking up acetylated low-density lipoprotein and forming capillary-vascular-like structures on Matrigel, these cells also demonstrated early cellular senescence (most of the endothelial cells senesced after one passage). Similarly, retinal pigmented epithelium cells derived from hiPSCs began senescing in the first passage. Before clinical application, it will he necessary to determine the cause and extent of such abnormalities and whether they also occur in hiPSCs generated using different reprogramming methods. [ABSTRACT FROM AUTHOR]

Published
2010
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18. Raf and Fibroblast Growth Factor Phosphorylate Elk1 and Activate the Serum Response Element of the Immediate Early Genepip92by Mitogen-Activated Protein Kinase-Independent as Well as -Dependent Signaling Pathways

Author

Chung, Kwang-Chul, Gomes, Ignatius, Wang, Danhui, Lau, Lester F., and Rosner, Marsha Rich

Abstract

ABSTRACTPrevious studies have shown that a mitogen activated protein (MAP) kinase (MEK)-independent signaling pathway is required by activated Raf or fibroblast-derived growth factor (FGF) for the differentiation of rat hippocampal neuronal H19-7 cells. We now demonstrate that both Raf and FGF similarly induce prolonged transcription and translation of the immediate early gene pip92in the absence of activation of the MAP kinases (MAPKs) ERK1 and ERK2. To determine the mechanism by which this occurs and to identify novel Raf-activated signaling pathways, we investigated the induction of the pip92promoter by both FGF and an estradiol-activated Raf-1–estrogen receptor fusion protein (ΔRaf-1:ER) in H19-7 cells. Deletion analysis of the pip92promoter indicated that activation by the MAPK-independent pathway occurs primarily within the region containing a serum response element (SRE). Further analysis of the SRE by using a heterologous thymidine kinase promoter showed that both an Ets and CArG-like site are required. Elk1, which binds to the Ets site, was phosphorylated both in vitro and in vivo by the MAPK-independent pathway, and phosphorylation of an Elk1-GAL4 fusion protein by this pathway was sufficient for transactivation. Finally, at least two Elk1 kinases were fractionated by gel filtration, and analysis by an in-gel kinase assay revealed at least three novel Raf-activated Elk1 kinases. These results indicate that both FGF and Raf activate MAPK-independent kinases that can stimulate Elk1 phosphorylation and immediate early gene transcription.

Published
1998
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