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Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin

Airway epithelial tight junction (TJ) proteins form a resistive barrier to the external environment, however, during respiratory bacterial infection TJs become disrupted compromising barrier function. This promotes glucose flux/accumulation into the lumen which acts as a nutrient source for bacteria...

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Autores principales: Kalsi, Kameljit K., Garnett, James P., Patkee, Wishwanath, Weekes, Alexina, Dockrell, Mark E., Baker, Emma H., Baines, Deborah L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307806/
https://www.ncbi.nlm.nih.gov/pubmed/30450773
http://dx.doi.org/10.1111/jcmm.13929
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author Kalsi, Kameljit K.
Garnett, James P.
Patkee, Wishwanath
Weekes, Alexina
Dockrell, Mark E.
Baker, Emma H.
Baines, Deborah L.
author_facet Kalsi, Kameljit K.
Garnett, James P.
Patkee, Wishwanath
Weekes, Alexina
Dockrell, Mark E.
Baker, Emma H.
Baines, Deborah L.
author_sort Kalsi, Kameljit K.
collection PubMed
description Airway epithelial tight junction (TJ) proteins form a resistive barrier to the external environment, however, during respiratory bacterial infection TJs become disrupted compromising barrier function. This promotes glucose flux/accumulation into the lumen which acts as a nutrient source for bacterial growth. Metformin used for the treatment of diabetes increases transepithelial resistance (TEER) and partially prevents the effect of bacteria but the mechanisms of action are unclear. We investigated the effect of metformin and Staphylococcus aureus on TJ proteins, zonula occludins (ZO)‐1 and occludin in human airway epithelial cells (H441). We also explored the role of AMP‐activated protein kinase (AMPK) and PKCζ in metformin‐induced effects. Pretreatment with metformin prevented the S. aureus‐induced changes in ZO‐1 and occludin. Metformin also promoted increased abundance of full length over smaller cleaved occludin proteins. The nonspecific PKC inhibitor staurosporine reduced TEER but did not prevent the effect of metformin indicating that the pathway may involve atypical PKC isoforms. Investigation of TJ reassembly after calcium depletion showed that metformin increased TEER more rapidly and promoted the abundance and localization of occludin at the TJ. These effects were inhibited by the AMPK inhibitor, compound C and the PKCζ pseudosubstrate inhibitor (PSI). Metformin increased phosphorylation of occludin and acetyl‐coA‐carboxylase but only the former was prevented by PSI. This study demonstrates that metformin improves TJ barrier function by promoting the abundance and assembly of full length occludin at the TJ and that this process involves phosphorylation of the protein via an AMPK‐PKCζ pathway.
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spelling pubmed-63078062019-01-04 Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin Kalsi, Kameljit K. Garnett, James P. Patkee, Wishwanath Weekes, Alexina Dockrell, Mark E. Baker, Emma H. Baines, Deborah L. J Cell Mol Med Original Articles Airway epithelial tight junction (TJ) proteins form a resistive barrier to the external environment, however, during respiratory bacterial infection TJs become disrupted compromising barrier function. This promotes glucose flux/accumulation into the lumen which acts as a nutrient source for bacterial growth. Metformin used for the treatment of diabetes increases transepithelial resistance (TEER) and partially prevents the effect of bacteria but the mechanisms of action are unclear. We investigated the effect of metformin and Staphylococcus aureus on TJ proteins, zonula occludins (ZO)‐1 and occludin in human airway epithelial cells (H441). We also explored the role of AMP‐activated protein kinase (AMPK) and PKCζ in metformin‐induced effects. Pretreatment with metformin prevented the S. aureus‐induced changes in ZO‐1 and occludin. Metformin also promoted increased abundance of full length over smaller cleaved occludin proteins. The nonspecific PKC inhibitor staurosporine reduced TEER but did not prevent the effect of metformin indicating that the pathway may involve atypical PKC isoforms. Investigation of TJ reassembly after calcium depletion showed that metformin increased TEER more rapidly and promoted the abundance and localization of occludin at the TJ. These effects were inhibited by the AMPK inhibitor, compound C and the PKCζ pseudosubstrate inhibitor (PSI). Metformin increased phosphorylation of occludin and acetyl‐coA‐carboxylase but only the former was prevented by PSI. This study demonstrates that metformin improves TJ barrier function by promoting the abundance and assembly of full length occludin at the TJ and that this process involves phosphorylation of the protein via an AMPK‐PKCζ pathway. John Wiley and Sons Inc. 2018-11-18 2019-01 /pmc/articles/PMC6307806/ /pubmed/30450773 http://dx.doi.org/10.1111/jcmm.13929 Text en © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Articles
Kalsi, Kameljit K.
Garnett, James P.
Patkee, Wishwanath
Weekes, Alexina
Dockrell, Mark E.
Baker, Emma H.
Baines, Deborah L.
Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title_full Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title_fullStr Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title_full_unstemmed Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title_short Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ‐mediated phosphorylation of occludin
title_sort metformin attenuates the effect of staphylococcus aureus on airway tight junctions by increasing pkcζ‐mediated phosphorylation of occludin
topic Original Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307806/
https://www.ncbi.nlm.nih.gov/pubmed/30450773
http://dx.doi.org/10.1111/jcmm.13929
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