title: Fibronectin-alpha4beta1 integrin interactions regulate metalloproteinase-9 expression in steatotic liver ischemia and reperfusion injury.
abstract: Ischemia/reperfusion injury is a major cause of the highly dysfunctional rate observed in marginal steatotic orthotopic liver transplantation. In this study, we document that the interactions between fibronectin, a key extracellular matrix protein, and its integrin receptor alpha4beta1, expressed on leukocytes, specifically up-regulated the expression and activation of metalloproteinase-9 (MMP-9, gelatinase B) in a well-established steatotic rat liver model of ex vivo ice-cold ischemia followed by isotransplantation. The presence of the active form of MMP-9 was accompanied by massive intragraft leukocyte infiltration, high levels of proinflammatory cytokines, such as interleukin-1beta and tumor necrosis factor-alpha, and impaired liver function. Interestingly, MMP-9 activity in steatotic liver grafts was, to a certain extent, independent of the expression of its natural inhibitor, the tissue inhibitor of metalloproteinases-1. Moreover, the blockade of fibronectin-alpha4beta1-integrin interactions inhibited the expression/activation of MMP-9 in steatotic orthotopic liver transplantations without significantly affecting the expression of metalloproteinase-2 (MMP-2, gelatinase A). Finally, we identified T lymphocytes and monocytes/macrophages as major sources of MMP-9 in steatotic liver grafts. Hence, these findings reveal a novel aspect of the function of fibronectin-alpha4beta1 integrin interactions that holds significance for the successful use of marginal steatotic livers in transplantation.
authors.affiliation: Dumont-UCLA Transplant Center, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7054, USA.
authors.forename: Carolina
authors.initials: C
authors.lastname: Moore
authors.forename: Xiu-Da
authors.initials: XD
authors.lastname: Shen
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Busuttil
authors.forename: Ana J
authors.initials: AJ
authors.lastname: Coito
mesh_terms: D000818:Animals; D050377:Cold Ischemia; D005234:Fatty Liver / Q000201:enzymology* / Q000473:pathology; D015971:Gene Expression Regulation, Enzymologic; D039041:Integrin alpha4beta1 / Q000378:metabolism*; D053583:Interleukin-1beta / Q000096:biosynthesis; D008099:Liver / Q000201:enzymology / Q000473:pathology; D016031:Liver Transplantation; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011924:Rats, Zucker; D015427:Reperfusion Injury / Q000201:enzymology* / Q000473:pathology; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis; D014185:Transplantation, Isogeneic; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D015854:Up-Regulation
chemical_list: D039041:Integrin alpha4beta1; D053583:Interleukin-1beta; D019715:Tissue Inhibitor of Metalloproteinase-1; D014409:Tumor Necrosis Factor-alpha; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9