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Gastrointestinal Cells (gastrointestinal + cell)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Somatostatin receptors and autoimmune-mediated diabetes

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2005
Xaio-Ping Wang
Abstract Somatostatin (SST) peptide is produced by various SST-secreting cells throughout the body and acts as a neurotransmitter or paracrine/autocrine regulator in response to ions, nutrients, peptides hormones and neurotransmitters. SST is also widely distributed in the periphery to regulate the inflammatory and immune cells in response to hormones, growth factors, cytokines and other secretive molecules. SST peptides are considered the most important physiologic regulator of the islet cell, gastrointestinal cell and immune cell functions, and the importance of SST production levels has been implicated in several diseases including diabetes. The expression of SST receptors has also been found in T lymphocytes and primary immunologic organs. Interaction of SST and its receptors is also involved in T-cell proliferation and thymocyte selection. SSTR gene-ablated mice developed diabetes with morphologic, physiologic and immunologic alterations in the endocrine pancreas. Increased levels of mononuclear cell infiltration of the islets are associated with the increased levels of antigen-presenting cells located in the islets and peripancreatic lymph nodes. Increased levels of SST were also found in antigen-presenting cells and are associated with a significant increase of CD8 expression levels on CD4+/CD8+ immature thymocytes. These findings highlight the crucial role of this neuroendocrine peptide and its receptors in regulating autoimmune functions. Copyright © 2004 John Wiley & Sons, Ltd. [source]

The Hek outer membrane protein of Escherichia coli is an auto-aggregating adhesin and invasin

FEMS MICROBIOLOGY LETTERS, Issue 2 2007
Robert P. Fagan
Abstract Escherichia coli is the principal gram-negative causative agent of sepsis and meningitis in neonates. The pathogenesis of meningitis due to E. coli K1 involves mucosal colonization, transcytosis of epithelial cells, survival in the blood stream and eventually invasion of the meninges. The latter two aspects have been well characterized at a molecular level in the last decade. Less is known about the early stages of pathogenesis, i.e. adhesion to and invasion of gastrointestinal cells. Here, the characterization of the Hek protein is reported, which is expressed by neonatal meningitic E. coli (NMEC) and is localized to the outer membrane. It is demonstrated that this protein can cause agglutination of red blood cells and can mediate autoaggregation. Escherichia coli expressing this protein can adhere to and invade epithelial cells. So far, this is the first outer membrane protein in NMEC to be directly implicated in epithelial cell invasion. [source]

Improved In vitro Model Systems for Gastrointestinal Infection by Choice of Cell Line, pH, Microaerobic Conditions, and Optimization of Culture Conditions

HELICOBACTER, Issue 4 2007
Sara K. Lindén
Abstract Background:, Commonly used in vitro infection cultures do not mimic the human gastrointestinal tract with regard to pH and microaerobic conditions. Furthermore, despite the importance of mucin,Helicobacter interactions, the cell lines used have not been selected for appropriate mucin expression. To make in vitro studies more applicable to human disease, we have developed coculture methods taking these factors into account. Materials and methods:, Nine human gastrointestinal epithelial cell lines (MKN1, MKN7, MKN28, MKN45, KATO3, HFE145, PCAA/C11 Caco-2, and LS513) were investigated. Expression and glycosylation of mucins (MUC1, 2, 3, 4, 5AC, 5B, 6, 12, 13, and 16) were determined by immunohistochemistry. We analyzed the effect of microaerobic conditions and acidic pH on cell proliferation, viability, and apoptosis. Results:, Microaerobic culture, which is more physiological for the bacteria, did not adversely affect mammalian cell viability, proliferation, or induce apoptosis The cell lines varied in mucin expression, with MKN7 and MKN45 being most similar to gastric mucosa and Caco-2 and LS513 to intestinal mucosa, although none exactly matched normal mucosa. However, changes in culture conditions did not cause major changes in the mucin expression within cell lines. Conclusions:, Culture conditions mimicking the natural environment and allowing the bacterial cells to thrive had no effect on cell viability or apoptosis, and very little influence on mucin expression of human gastrointestinal cells. Thus, it is feasible, using the simple methods we present here, to substantially improve bacterial,mammalian cell in vitro coculture studies to make them more reflective of human infection. [source]

Norovirus binds to blood group A-like antigens in oyster gastrointestinal cells

LETTERS IN APPLIED MICROBIOLOGY, Issue 6 2006
P. Tian
Abstract Aims:, To determine if histo-blood group antigens (HBGA) present in oyster gastrointestinal (GI) cells mediate accumulation of human noroviruses (NoV) in oyster GI cells. Methods and Results:, HBGA-specific monoclonal antibodies (MAbs) were used to determine the presence of the corresponding HBGA in oyster GI cells. All oyster samples tested contained type A-like HBGA in GI tissue as measured by ELISA. Recombinant Norwalk virus viral like particles (rNVLP) were bound to plates coated with oyster GI homogenate. The binding was inhibited when rNVLPs were pre-incubated with MAbs specific for type A HBGA, or samples of human saliva from type A individuals. Co-localization of rNVLP and type A-like HBGA, but not type B-like or type H-like HBGA, on GI epithelial cells was observed by immunofluorescent histochemical staining and three-channel confocal scanning laser microscopy. Conclusion:, Type A-like HBGA is present in oyster GI cells and responsible for binding of rNVLP. Significance and Impact of the Study:, This is the first report of the presence of type A-like HBGA in oyster GI cells and the specific binding of rNVLP to type A-like HBGA on oyster GI cells. The results of this study suggest that human NoV concentrate in oyster GI cells by specific binding to concentrated type A-like HBGA rather than by a nonmolecular entrapment within the tissues. [source]