Abstract
We have prepared 125I-labeled cholera toxin B subunit (125I-labeled CT-B, a specific activity of 98Ci/mmol) and found that it binds to rat IEC-6 and human Caco-2 intestinal epithelial cells with high affinity (Kd 3.6 and 3.7nM, respectively). The binding of labeled protein was completely inhibited by unlabeled thymosin-α1 (TM-α1), interferon-α2 (IFN-α2), and the synthetic peptide LKEKK that corresponds to residues 16-20 in TM-α1 and 131-135 in IFN-α2, but was not inhibited by the synthetic peptide KKEKL with inverted amino acid sequence (Ki>10μM). Thus, TM-α1, IFN-α2, and the peptide: LKEKK bind with high affinity and specificity to the cholera toxin receptor on IEC-6 and Caco-2 cells. It was found that CT-B and the peptide: LKEKK at concentrations of 10-1000nM increased in a dose-dependent manner the nitric oxide production and the soluble guanylate cyclase activity in IEC-6 and Caco-2 cells.
Keywords:
Cholera toxin B subunit; Interferon-α; Intestinal epithelial cells; Protein: Peptide; Receptor; Thymosin-α(1).
Copyright © 2017 Elsevier Ltd. All rights reserved.
MeSH terms
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Animals
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Anti-Inflammatory Agents, Non-Steroidal / metabolism
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Anti-Inflammatory Agents, Non-Steroidal / pharmacology
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Binding Sites
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Binding, Competitive
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Caco-2 Cells
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Cell Line
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Cholera Toxin / metabolism*
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Cholera Toxin / pharmacology
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G(M1) Ganglioside / agonists
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G(M1) Ganglioside / metabolism*
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Guanylate Cyclase / chemistry
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Guanylate Cyclase / metabolism
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Humans
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Interferon-alpha / chemistry
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Interferon-alpha / metabolism
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Intestinal Mucosa / drug effects
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Intestinal Mucosa / enzymology
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Intestinal Mucosa / metabolism*
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Iodine Radioisotopes
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Kinetics
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Ligands
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Nitric Oxide / agonists
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Nitric Oxide / metabolism
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Oligopeptides / chemistry
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Oligopeptides / metabolism
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Oligopeptides / pharmacology
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Peptide Fragments / chemistry
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Peptide Fragments / metabolism
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Peptide Fragments / pharmacology
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Rats
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Receptors, Cell Surface / agonists
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Receptors, Cell Surface / metabolism*
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Thymosin / chemistry
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Thymosin / metabolism
Substances
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Anti-Inflammatory Agents, Non-Steroidal
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IFNA2 protein, human
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Interferon-alpha
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Iodine Radioisotopes
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Ligands
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Oligopeptides
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Peptide Fragments
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Receptors, Cell Surface
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choleragen receptor
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Nitric Oxide
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G(M1) Ganglioside
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Thymosin
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Cholera Toxin
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Guanylate Cyclase