Deletion of Wntless in myeloid cells exacerbates liver fibrosis and the ductular reaction in chronic liver injury

Irvine, Katharine M., Clouston, Andrew D., Gadd, Victoria L., Miller, Gregory C., Wong, Weng-Yew, Melino, Michelle, Maradana, Muralidhara Rao, MacDonald, Kelli, Lang, Richard A., Sweet, Matthew J., Blumenthal, Antje and Powell, Elizabeth E. (2015) Deletion of Wntless in myeloid cells exacerbates liver fibrosis and the ductular reaction in chronic liver injury. Fibrogenesis and Tissue Repair, 8 19: . doi:10.1186/s13069-015-0036-7

Author Irvine, Katharine M.
Clouston, Andrew D.
Gadd, Victoria L.
Miller, Gregory C.
Wong, Weng-Yew
Melino, Michelle
Maradana, Muralidhara Rao
MacDonald, Kelli
Lang, Richard A.
Sweet, Matthew J.
Blumenthal, Antje
Powell, Elizabeth E.
Title Deletion of Wntless in myeloid cells exacerbates liver fibrosis and the ductular reaction in chronic liver injury
Journal name Fibrogenesis and Tissue Repair   Check publisher's open access policy
ISSN 1755-1536
Publication date 2015-10-15
Year available 2015
Sub-type Article (original research)
DOI 10.1186/s13069-015-0036-7
Open Access Status DOI
Volume 8
Issue 19
Total pages 13
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2016
Language eng
Formatted abstract
Background: Macrophages play critical roles in liver regeneration, fibrosis development and resolution. They are among the first responders to liver injury and are implicated in orchestrating the fibrogenic response via multiple mechanisms. Macrophages are also intimately associated with the activated hepatic progenitor cell (HPC) niche or ductular reaction that develops in parallel with fibrosis. Among the many macrophage-derived mediators implicated in liver disease progression, a key role for macrophage-derived Wnt proteins in driving pro-regenerative HPC activation towards a hepatocellular fate has been suggested. Wnt proteins, in general, however, have been associated with both pro- and anti-fibrogenic activities in the liver and other organs. We investigated the role of macrophage-derived Wnt proteins in fibrogenesis and HPC activation in murine models of chronic liver disease by conditionally deleting Wntless expression, which encodes a chaperone essential for Wnt protein secretion, in LysM-Cre-expressing myeloid cells (LysM-Wls mice).

Results: Fibrosis and HPC activation were exacerbated in LysM-Wls mice compared to littermate controls, in the absence of an apparent increase in myofibroblast activation or interstitial collagen mRNA expression, in both the TAA and CDE models of chronic liver disease. Increased Epcam mRNA levels paralleled the increased HPC activation and more mature ductular reactions, in LysM-Wls mice. Increased Epcam expression in LysM-Wls HPC was also observed, consistent with a more cholangiocytic phenotype. No differences in the mRNA expression levels of key pro-inflammatory and pro-fibrotic cytokines or the macrophage-derived HPC mitogen, Tweak, were observed. LysM-Wls mice exhibited increased expression of Timp1, encoding the key Mmp inhibitor Timp1 that blocks interstitial collagen degradation, and, in the TAA model, reduced expression of the anti-fibrotic matrix metalloproteinases, Mmp12 and Mmp13, suggesting a role for macrophage-derived Wnt proteins in restraining fibrogenesis during ongoing liver injury.

Conclusion: In summary, these data suggest that macrophage-derived Wnt proteins possess anti-fibrogenic potential in chronic liver disease, which may be able to be manipulated for therapeutic benefit.
Keyword Liver fibrosis
Ductular reaction
Matrix remodelling
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

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