The organ shortage has prompted the use of marginal livers, which are particularly susceptible to ischemia- reperfusion injury (IRI). We discovered that Nrf2 deficiency in the donor liver exacerbates IRI in mouse orthotopic liver transplantation (OLT). However, IRI was prevented if donor livers were conditioned with bone marrow-derived cells overexpressing HO-1. The success of organ rejuvenation was lost after abrogation of SIRT1 activity. Our hypothesis is that SIRT1 signaling in the donor liver: 1/ dictates the rejuvenation outcomes, in which Nrf2 expression represents a denominator of donor liver quality; 2/ serves as a rheostat that controls innate inflammation/regulates hepatocyte regeneration in IR-stressed OLT. We propose three specific aims:
Aim 1 : Define molecular mechanisms by which SIRT1 signaling controls macrophage inflammation in IR- stressed OLT.
Aim 1. 1: Test whether activation of macrophage Nrf2 - SIRT1 in the donor liver depresses NF?B signaling/inflammation in IR-stressed OLT.
Aim 1. 2: Test whether upregulation of SIRT1 in the donor liver depresses the inflammasome platform to block NF?B signaling/inflammation. We will screen for SIRT1- mediated deacetylation of NF?B and expression of SIRT1 regulators (AROS/DBC-1). Then, we will utilize a model of liver IRI in CD11b-DTR mice to dissect SIRT1 - inflammasome cross-regulation in IR-inflammation.
Aim 2 : Define molecular mechanisms by which SIRT1 signaling regulates hepatocyte regenerative responses in IR-stressed OLT.
Aim 2. 1: Test whether SIRT1-dependent activation of hepatocyte ?-catenin in the donor liver facilitates cytoprotection in IR-stressed OLT. We will screen for ?-catenin deacetylation under control of SIRT1 regulators (AROS/DBC-1), and then focus on cyclin-D1, and its role in promoting hepatocyte proliferation.
Aim 2. 2: Test whether SIRT1 activation of parenchyma cell autophagy is required for hepatocyte regeneration in IR-stressed OLT. Two lines of in-vivo (IR-stressed OLT) and in-vitro (H2O2-stressed hepatocyte cultures) studies will assess the significance and mechanisms of enhanced autophagy in SIRT1HI environment (promoting liver rejuvenation) vs. diminished autophagy in SIRT1null environment (sensitizing liver to IRI).
Aim 3 : Define whether ex-vivo manipulation of Nrf2-SIRT1 axis during hypothermic machine perfusion (HMP) may rescue human discarded livers.
Aim 3. 1: Test hypothesis that induction of SIRT1 restores function of discarded human livers. Livers deemed unusable will be randomized to: 1/ unmodified HMP; 2/ HMP + SIRT1 activator. The effluent/liver biopsies are analyzed for hepatocellular injury; clearance; biliary function; and hepatic energy status.
Aim 3. 2: Test hypothesis that hepatic SIRT1 activation rejuvenates human livers. Perfusate/biopsy samples will be screened for the expression of Keap1/Nrf2; SIRT1/inflammasome platform; pro/anti-inflammatory cytokine/chemokine programs; hepatocyte death and ?-catenin/autophagy pathways. Our findings should facilitate innovative donor interventions to improve the quality/size of the current organ supply, an absolute imperative for the full realization of succes for solid organ transplantation.

Public Health Relevance

The shortage and poor quality of donor organs represent major limitations facing liver transplantation, the gold standard of care in patients with end-stag liver disease and those with tumors of hepatic origin. The goal of this project is to increase the organ donor pool by 'rejuvenating' hepatic tissue, and hence promoting homeostasis and improving liver transplantation outcomes. .

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK062357-12
Application #
9234523
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Burgess-Beusse, Bonnie L
Project Start
2002-07-01
Project End
2021-02-28
Budget Start
2017-03-01
Budget End
2018-02-28
Support Year
12
Fiscal Year
2017
Total Cost
$384,253
Indirect Cost
$134,737
Name
University of California Los Angeles
Department
Surgery
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Zhang, Cheng; Zhang, Yu; Liu, Yuanxing et al. (2016) A soluble form of PSGL-1 requires Nrf2 signaling to protect liver transplant endothelial cells against ischemia-reperfusion injury. Am J Transplant :
Liu, Y; Ji, H; Zhang, Y et al. (2015) Negative CD4 + TIM-3 signaling confers resistance against cold preservation damage in mouse liver transplantation. Am J Transplant 15:954-64
Liu, Yuanxing; Ji, Haofeng; Zhang, Yu et al. (2015) Recipient T cell TIM-3 and hepatocyte galectin-9 signalling protects mouse liver transplants against ischemia-reperfusion injury. J Hepatol 62:563-72
Huang, Jing; Yue, Shi; Ke, Bibo et al. (2014) Nuclear factor erythroid 2-related factor 2 regulates toll-like receptor 4 innate responses in mouse liver ischemia-reperfusion injury through Akt-forkhead box protein O1 signaling network. Transplantation 98:721-8
Huang, Jing; Shen, Xiu-Da; Yue, Shi et al. (2014) Adoptive transfer of heme oxygenase-1 (HO-1)-modified macrophages rescues the nuclear factor erythroid 2-related factor (Nrf2) antiinflammatory phenotype in liver ischemia/reperfusion injury. Mol Med 20:448-55
Ji, Haofeng; Liu, Yuanxing; Zhang, Yu et al. (2014) T-cell immunoglobulin and mucin domain 4 (TIM-4) signaling in innate immune-mediated liver ischemia-reperfusion injury. Hepatology 60:2052-64
Zhang, Y; Ji, H; Shen, X et al. (2013) Targeting TIM-1 on CD4 T cells depresses macrophage activation and overcomes ischemia-reperfusion injury in mouse orthotopic liver transplantation. Am J Transplant 13:56-66
Ji, Haofeng; Zhang, Yu; Liu, Yuanxing et al. (2013) Vasoactive intestinal peptide attenuates liver ischemia/reperfusion injury in mice via the cyclic adenosine monophosphate-protein kinase a pathway. Liver Transpl 19:945-56
Ke, Bibo; Shen, Xiu-Da; Zhang, Yu et al. (2013) KEAP1-NRF2 complex in ischemia-induced hepatocellular damage of mouse liver transplants. J Hepatol 59:1200-7
Ji, Haofeng; Zhang, Yu; Shen, Xiu-da et al. (2013) Neuropeptide PACAP in mouse liver ischemia and reperfusion injury: immunomodulation by the cAMP-PKA pathway. Hepatology 57:1225-37

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