Brief Article
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World J Biol Chem. Nov 26, 2010; 1(11): 338-347
Published online Nov 26, 2010. doi: 10.4331/wjbc.v1.i11.338
Modulation of protein tyrosine phosphorylation in gastric mucosa during re-epithelization processes
Olena V Bogdanova, Larysa I Kot, Kateryna V Lavrova, Volodymyr B Bogdanov, Erica K Sloan, Tetyana V Beregova, Ludmyla I Ostapchenko
Olena V Bogdanova, Larysa I Kot, Kateryna V Lavrova, Ludmyla I Ostapchenko, Department of Biochemistry, Taras Shevchenko National University of Kyiv, Kyiv, 01033, Ukraine
Volodymyr B Bogdanov, Department of Human and Animal Physiology, Taras Shevchenko National University of Kyiv, Kyiv, 01033, Ukraine
Erica K Sloan, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, CA 90095, United States
Tetyana V Beregova, Department of Pharmaco-physiology, Taras Shevchenko National University of Kyiv, Kyiv, 01033, Ukraine
Author contributions: Bogdanova OV, Kot LI and Lavrova KV designed and performed the research, Bogdanov VB analyzed the data and prepared the figures; Bogdanova OV wrote the paper; Sloan EK revised the English version of the manuscript; Beregova TV and Ostapchenko LI were involved in research design and editing the manuscript.
Supported by Travel grants from The Physiological Society (UK and Eire), Federation of European Physiological Societies and The Cousins Center for Psychoneuroimmunology at the UCLA Neuropsychiatric Institute travel assistant award
Correspondence to: Olena V Bogdanova, PhD, Department of Biochemistry, Taras Shevchenko National University of Kyiv, Volodymyrska str., 64, Kyiv, 01033, Ukraine. basilevsis@yahoo.com
Telephone: +38-44-5220828 Fax: +38-44-5220828
Received: July 15, 2010
Revised: September 13, 2010
Accepted: September 20, 2010
Published online: November 26, 2010
Abstract

AIM: To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration.

METHODS: Gastric lesions were induced in rats using restraint cold stress. To investigate the effect of oxidative and nitrosative cell stress on tyrosine phosphorylation during wound repair, total activity of protein tyrosine kinase (PTK), protein tyrosine phosphatase (PTP), antioxidant enzymes, nitric oxide synthase (NOS), 2’,5’-oligoadenylate synthetase, hydroxyl radical and zinc levels were assayed in parallel.

RESULTS: Ulcer provocation induced an immediate decrease in tyrosine kinase (40% in plasma membranes and 56% in cytosol, P < 0.05) and phosphatase activity (threefold in plasma membranes and 3.3-fold in cytosol), followed by 2.3-2.4-fold decrease (P < 0.05) in protein phosphotyrosine content in the gastric mucosa. Ulceration induced no immediate change in superoxide dismutase (SOD) activity, 30% increase (P < 0.05) in catalase activity, 2.3-fold inhibition (P < 0.05) of glutathione peroxidase, 3.3-fold increase (P < 0.05) in hydroxyl radical content, and 2.3-fold decrease (P < 0.05) in zinc level in gastric mucosa. NOS activity was three times higher in gastric mucosa cells after cold stress. Following ulceration, PTK activity increased in plasma membranes and reached a maximum on day 4 after stress (twofold increase, P < 0.05), but remained inhibited (1.6-3-fold decrease on days 3, 4 and 5, P < 0.05) in the cytosol. Tyrosine phosphatases remained inhibited both in membranes and cytosol (1.5-2.4-fold, P < 0.05). NOS activity remained increased on days 1, 2 and 3 (3.8-, 2.6-, 2.2-fold, respectively, P < 0.05). Activity of SOD increased 1.6 times (P < 0.05) days 4 and 5 after stress. Catalase activity normalized after day 2. Glutathione peroxidase activity and zinc level decreased (3.3- and 2-fold, respectively, P < 0.05) on the last day. Activity of 2’,5’-oligoadenylate synthethase increased 2.8-fold (P < 0.05) at the beginning, and 1.6-2.3-fold (P < 0.05) during ulcer recuperation, and normalized on day 5, consistent with slowing of inflammation processes.

CONCLUSION: These studies show diverse changes in total tyrosine kinase activity in gastric mucosa during the recovery process. Oxidative and nitrosative stress during lesion formation might lead to the observed reduction in tyrosine phosphorylation during ulceration.

Keywords: Protein tyrosine kinase, Protein tyrosine phosphatase, Antioxidants, Gastric ulcer, Wound repair