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The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells
BACKGROUND & AIMS: A fenestrated phenotype is characteristic of liver sinusoidal endothelial cells (LSECs), but liver sinusoids become defenestrated during fibrosis and other liver diseases. Thrombospondin-1 (TSP1) is a matrix glycoprotein with pro-fibrotic effects, and the CD47-binding fragment...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BlackWell Publishing Ltd
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4285809/ https://www.ncbi.nlm.nih.gov/pubmed/23799952 http://dx.doi.org/10.1111/liv.12231 |
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author | Venkatraman, Lakshmi Tucker-Kellogg, Lisa |
author_facet | Venkatraman, Lakshmi Tucker-Kellogg, Lisa |
author_sort | Venkatraman, Lakshmi |
collection | PubMed |
description | BACKGROUND & AIMS: A fenestrated phenotype is characteristic of liver sinusoidal endothelial cells (LSECs), but liver sinusoids become defenestrated during fibrosis and other liver diseases. Thrombospondin-1 (TSP1) is a matrix glycoprotein with pro-fibrotic effects, and the CD47-binding fragment of TSP1 also has anti-angiogenic effects in endothelial cells. We hypothesized that the CD47-binding fragment of TSP1 could induce defenestration in LSECs through the Rho-Rho kinase (ROCK)-myosin pathway. METHODS: Freshly isolated rat LSECs were treated with TSP1 or CD47-binding peptides of TSP1. LSEC fenestration was assessed with scanning electron microscopy, and myosin phosphorylation was assessed with immuno-fluorescence. RESULTS: Treating LSECs with TSP1 caused a dose-dependent loss of fenestrae, and this effect could not be blocked by SB-431542, the TGF-β1 receptor inhibitor. A CD47-binding fragment of TSP1, p4N1, was able to induce defenestration, and a CD47-blocking antibody, B6H12, was able to suppress p4N1-induced defenestration. The p4N1 fragment also caused contraction of fenestra size, correlated with an increase in myosin activation. Pretreatment with Y-237642 (a ROCK inhibitor) prevented p4N1-induced myosin activation and fenestrae decrease. Simvastatin has also been shown to antagonize Rho-ROCK signalling, and we found that simvastatin pretreatment protected LSECs from p4N1-induced myosin activation and defenestration. CONCLUSIONS: We conclude that CD47 signals through the Rho-ROCK-myosin pathway to induce defenestration in LSECs. In addition, our results show that simvastatin and Y-237642 have a beneficial impact on fenestration in vitro, providing an additional explanation for the efficacy of these compounds for regression of liver fibrosis. |
format | Online Article Text |
id | pubmed-4285809 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | BlackWell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-42858092015-01-14 The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells Venkatraman, Lakshmi Tucker-Kellogg, Lisa Liver Int Original Articles BACKGROUND & AIMS: A fenestrated phenotype is characteristic of liver sinusoidal endothelial cells (LSECs), but liver sinusoids become defenestrated during fibrosis and other liver diseases. Thrombospondin-1 (TSP1) is a matrix glycoprotein with pro-fibrotic effects, and the CD47-binding fragment of TSP1 also has anti-angiogenic effects in endothelial cells. We hypothesized that the CD47-binding fragment of TSP1 could induce defenestration in LSECs through the Rho-Rho kinase (ROCK)-myosin pathway. METHODS: Freshly isolated rat LSECs were treated with TSP1 or CD47-binding peptides of TSP1. LSEC fenestration was assessed with scanning electron microscopy, and myosin phosphorylation was assessed with immuno-fluorescence. RESULTS: Treating LSECs with TSP1 caused a dose-dependent loss of fenestrae, and this effect could not be blocked by SB-431542, the TGF-β1 receptor inhibitor. A CD47-binding fragment of TSP1, p4N1, was able to induce defenestration, and a CD47-blocking antibody, B6H12, was able to suppress p4N1-induced defenestration. The p4N1 fragment also caused contraction of fenestra size, correlated with an increase in myosin activation. Pretreatment with Y-237642 (a ROCK inhibitor) prevented p4N1-induced myosin activation and fenestrae decrease. Simvastatin has also been shown to antagonize Rho-ROCK signalling, and we found that simvastatin pretreatment protected LSECs from p4N1-induced myosin activation and defenestration. CONCLUSIONS: We conclude that CD47 signals through the Rho-ROCK-myosin pathway to induce defenestration in LSECs. In addition, our results show that simvastatin and Y-237642 have a beneficial impact on fenestration in vitro, providing an additional explanation for the efficacy of these compounds for regression of liver fibrosis. BlackWell Publishing Ltd 2013-10 2013-06-26 /pmc/articles/PMC4285809/ /pubmed/23799952 http://dx.doi.org/10.1111/liv.12231 Text en © 2013 The Authors. Liver International published by John Wiley & Sons Ltd http://creativecommons.org/licenses/by-nc/3.0/ This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
spellingShingle | Original Articles Venkatraman, Lakshmi Tucker-Kellogg, Lisa The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title | The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title_full | The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title_fullStr | The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title_full_unstemmed | The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title_short | The CD47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
title_sort | cd47-binding peptide of thrombospondin-1 induces defenestration of liver sinusoidal endothelial cells |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4285809/ https://www.ncbi.nlm.nih.gov/pubmed/23799952 http://dx.doi.org/10.1111/liv.12231 |
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