title: Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.
abstract: Collagen stabilization through irreversible cross-linking is thought to promote hepatic fibrosis progression and limit its reversibility. However, the mechanism of this process remains poorly defined. We studied the functional contribution of lysyl oxidase (LOX) to collagen stabilization and hepatic fibrosis progression/reversalin vivousing chronic administration of irreversible LOX inhibitor β-aminopropionitrile (BAPN, or vehicle as control) in C57Bl/6J mice with carbon tetrachloride (CCl4)-induced fibrosis. Fibrotic matrix stability was directly assessed using a stepwise collagen extraction assay and fibrotic septae morphometry. Liver cells and fibrosis were studied by histologic, biochemical methods and quantitative real-time reverse-transcription PCR. During fibrosis progression, BAPN administration suppressed accumulation of cross-linked collagens, and fibrotic septae showed widening and collagen fibrils splitting, reminiscent of remodeling signs observed during fibrosis reversal. LOX inhibition attenuated hepatic stellate cell activation markers and promoted F4/80-positive scar-associated macrophage infiltration without an increase in liver injury. In reversal experiments, BAPN-treated fibrotic mice demonstrated accelerated fibrosis reversal after CCl4withdrawal. Our findings demonstrate for the first time that LOX contributes significantly to collagen stabilization in liver fibrosis, promotes fibrogenic activation of attenuated hepatic stellate cells, and limits fibrosis reversal. Our data support the concept of pharmacologic targeting of LOX pathway to inhibit liver fibrosis and promote its resolution.-Liu, S. B., Ikenaga, N., Peng, Z.-W., Sverdlov, D. Y., Greenstein, A., Smith, V., Schuppan, D., Popov, Y. Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Liu
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ikenaga
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Zhen-Wei
authors.initials: ZW
authors.lastname: Peng
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Deanna Y
authors.initials: DY
authors.lastname: Sverdlov
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Andrew
authors.initials: A
authors.lastname: Greenstein
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Victoria
authors.initials: V
authors.lastname: Smith
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany.
authors.forename: Detlef
authors.initials: D
authors.lastname: Schuppan
authors.affiliation: *Division of Gastroenterology and Hepatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Gilead Sciences, Inc., Foster City, California, USA; and Institute of Translational Immunology, University Medical Center, Mainz, Germany ypopov@bidmc.harvard.edu.
authors.forename: Yury
authors.initials: Y
authors.lastname: Popov
mesh_terms: D000629:Aminopropionitrile / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D002251:Carbon Tetrachloride; D003094:Collagen / Q000378:metabolism*; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D000090602:Collagen Type I, alpha 1 Chain; D018450:Disease Progression; D005355:Fibrosis; D015870:Gene Expression / Q000187:drug effects; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism; D007274:Injections, Intraperitoneal; D008099:Liver / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D008106:Liver Cirrhosis, Experimental / Q000139:chemically induced / Q000378:metabolism* / Q000517:prevention & control; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000379:methods; D008249:Protein-Lysine 6-Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D000629:Aminopropionitrile; D003094:Collagen; D002251:Carbon Tetrachloride; D008249:Protein-Lysine 6-Oxidase; D053509:Matrix Metalloproteinase 13
keywords: BAPN; CCl4; collagen cross-linking; hepatic stellate cells