lschemia reperfusion (I/R) injury remains a major limitation in orthotopic liver transplantation (OLT), particularly with marginal grafts. Very little is known about the mechanisms involved on leukocyte recruitment into sites of inflammatory stimulation in liver. Based upon evidence from our previous studies, we hypothesize that fibronectin (FN) is an integral part of the antigen independent cascade leading to liver I/R injury, likely providing a spatial address at which appropriate co-stimulatory signals can initiate leukocyte signaling and recruitment. We expect this proposal will unveil novel mechanisms and potential targets against I/R injury. Therefore, we propose to address the following specific aims: 1 . To analyze the function of distinct FN-alpha4beta1/alpha5beta1interactions upon leukocyte recruitment and cytokine release in liver I/R injury: Livers from genetically fat Zucker and non-steatotic SD rats will be stored at 4C in UW before being transplanted into syngeneic lean Zucker/SD rats, and the three distinct FN (EIIIA)-alpha4beta1, FN (CS1)-alpha4beta1,and FN (RGD)-alpha5beta1 interactions will be targeted with specific peptides and function-blocking mAbs. The distinct therapeutic manipulation upon (i) hepatic function and survival; (ii) leukocyte adhesion/migration (in vivo and in-vitro), and (iii) cytokine expression, will be probed. 2. To dissect mechanisms of FN-alpha4beta1/alpha5beta1 integrin action upon metalloproteinase-2 (MMP-2) and metalloproteinase-9 (MMP-9) expression in liver I/R Injury: We plan to (i) determine the contribution of distinct FN cell binding sites upon MMP-2 and MMP-9 expression/activation, and respective inhibitors (TIMP-2 and TIMP-1) in rat OLT; (ii) identify the individual sources of MMP-2 and MMP-9 in liver grafts; and (iii) evaluate the functional significance of MMP-2 and MMP-9 expression in the mechanisms of FN-integrin interactions upon liver I/R injury. 3. To explore the interplay between inducible nitric oxide synthase (iNOS), MMPs, and cytokines in the context of FN in liver I/R injury: First, the functional significance of iNOS expression will be probed in vivo with 1400W, a specific iNOS inhibitor. Second, we will dissect the interplay between TNF-alpha or other relevant cytokines, and iNOS upon FN regulation of MMP expression/activation. Third, we will unveil intracellular mechanisms, such as MAPKinase transduction pathways upon leukocyte adhesion to fibronectin and MMP expression.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
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Surgery, Anesthesiology and Trauma Study Section (SAT)
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Kehn, Patricia J
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University of California Los Angeles
Schools of Medicine
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Kato, Hiroyuki; Duarte, Sergio; Miller, Mary G et al. (2018) Overproduction of Tenascin-C Driven by Lipid Accumulation in Liver Aggravates Hepatic Ischemia and Reperfusion Injury in Steatotic Mice. Liver Transpl :
Kato, Hiroyuki; Duarte, Sergio; Liu, Daniel et al. (2015) Matrix Metalloproteinase-2 (MMP-2) Gene Deletion Enhances MMP-9 Activity, Impairs PARP-1 Degradation, and Exacerbates Hepatic Ischemia and Reperfusion Injury in Mice. PLoS One 10:e0137642
Duarte, Sergio; Baber, John; Fujii, Takehiro et al. (2015) Matrix metalloproteinases in liver injury, repair and fibrosis. Matrix Biol 44-46:147-56
Duarte, Sergio; Kato, Hiroyuki; Kuriyama, Naohisa et al. (2014) Hepatic ischemia and reperfusion injury in the absence of myeloid cell-derived COX-2 in mice. PLoS One 9:e96913
Kato, Hiroyuki; Kuriyama, Naohisa; Duarte, Sergio et al. (2014) MMP-9 deficiency shelters endothelial PECAM-1 expression and enhances regeneration of steatotic livers after ischemia and reperfusion injury. J Hepatol 60:1032-9
Hong, Johnny C; Koroleff, Dimitri; Xia, Victor et al. (2012) Regulated hepatic reperfusion mitigates ischemia-reperfusion injury and improves survival after prolonged liver warm ischemia: a pilot study on a novel concept of organ resuscitation in a large animal model. J Am Coll Surg 214:505-15; discussion 515-6
Duarte, S; Shen, X-D; Fondevila, C et al. (2012) Fibronectin-?4?1 interactions in hepatic cold ischemia and reperfusion injury: regulation of MMP-9 and MT1-MMP via the p38 MAPK pathway. Am J Transplant 12:2689-99
Duarte, Sergio; Hamada, Takashi; Kuriyama, Naohisa et al. (2012) TIMP-1 deficiency leads to lethal partial hepatic ischemia and reperfusion injury. Hepatology 56:1074-85
Kuriyama, Naohisa; Duarte, Sergio; Hamada, Takashi et al. (2011) Tenascin-C: a novel mediator of hepatic ischemia and reperfusion injury. Hepatology 54:2125-36
Coito, Ana J (2011) Leukocyte transmigration across endothelial and extracellular matrix protein barriers in liver ischemia/reperfusion injury. Curr Opin Organ Transplant 16:34-40

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