Our goal is to understand the molecular interactions that regulate the immune response during graft rejection. Multiple studies indicate that graft rejection is complex, polygenic and poorly understood. To investigate the network of molecular interactions that regulate rejection, in this proposal we apply a systems biology analysis to a well-characterized model of transplantation. Using a murine model of heart transplantation, our preliminary data demonstrate that a deficiency of graft produced IL-6 approximately triples graft survival. Graft produced IL6 overcomes suppression by regulatory T cells, and promotes the activation of CD4 and CD8 T effector cells. Thus, graft-produced IL6 functions as a molecular trigger that modulates multiple components of the immune response following transplantation. The experimental approach designed by our laboratory to investigate this complex process has 2 complementary components. First, we will investigate an important observation (prolongation of graft survival due to a deficiency of graft-produced IL-6) in an established solid organ transplant model (murine cardiac transplantation). Second, we will apply state of the art microarray technology, bioinformatics, biostatistics, and systems biology to construct and analyze global molecular models of the regulatory interactions and signal transduction pathways modulating rejection. Our preliminary data and recent publications establish that we can successfully perform these studies. Thus, we propose that applying a systems biology approach, which is the backbone of this application, is appropriate, timely, and synergistic with conventional approaches, to increase understanding of the rejection response. Our overall biological hypothesis is that injury to graft tissue induces IL6 secretion, which functions as a systemic danger signal to activate peripheral immune cells. We will employ both reductionist and systems approaches to address these questions.
In Aim I, we will identify candidate signal transduction pathways modulated by graft-produced IL-6 following transplantation.
In Aim II, we will predict biological responses for targets of knockdown experiments with RNAi using subnetworks and signal transduction pathways. We anticipate that our systems based approach will provide novel insights into the regulation of immune responses following transplantation and has the potential to identify new therapeutic strategies to prevent the rejection of grafted organs.

Public Health Relevance

We will investigate the immune mechanisms that may be important in determining whether a transplant is accepted or rejected by the patient. We are focusing on interleukin-6 (IL- 6), a cytokine with diverse functions. We have found that IL-6 produced by the donor graft accelerates rejection of the graft. In addition to IL-6, we will analyze immune genes and pathways using microarrays and construct biological interaction networks using systems biology methods to investigate the signals that promote rejection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI075317-01A2
Application #
7741350
Study Section
Transplantation, Tolerance, and Tumor Immunology (TTT)
Program Officer
Rice, Jeffrey S
Project Start
2009-08-01
Project End
2012-07-31
Budget Start
2009-08-01
Budget End
2010-07-31
Support Year
1
Fiscal Year
2009
Total Cost
$270,375
Indirect Cost
Name
University of California San Diego
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Rani, Asha; Ranjan, Ravi; McGee, Halvor S et al. (2017) Urinary microbiome of kidney transplant patients reveals dysbiosis with potential for antibiotic resistance. Transl Res 181:59-70
Kadota, Paul Ostrom; Hajjiri, Zahraa; Finn, Patricia W et al. (2015) Precision Subtypes of T Cell-Mediated Rejection Identified by Molecular Profiles. Front Immunol 6:536
Nakajima, Takeshi; Lin, Ko-Wei; Li, Jinghong et al. (2014) T cells and lung injury. Impact of rapamycin. Am J Respir Cell Mol Biol 51:294-9
Verma, Meenakshi; Awdishu, Linda; Lane, James et al. (2014) Impact of single immunosuppressive drug withdrawal on lymphocyte immunoreactivity. J Surg Res 188:309-15
Li, Jinghong; Lin, Ko-Wei; Murray, Fiona et al. (2013) Regulation of cytotoxic T lymphocyte antigen 4 by cyclic AMP. Am J Respir Cell Mol Biol 48:63-70
Lwin, Wint Wah; Park, Ken; Wauson, Matthew et al. (2012) Systems biology approach to transplant tolerance: proof of concept experiments using RNA interference (RNAi) to knock down hub genes in Jurkat and HeLa cells in vitro. J Surg Res 176:e41-6
Nakajima, Takeshi; Palchevsky, Vyachesav; Perkins, David L et al. (2011) Lung transplantation: infection, inflammation, and the microbiome. Semin Immunopathol 33:135-56
Lin, Ko-Wei; Li, Jinghong; Finn, Patricia W (2011) Emerging pathways in asthma: innate and adaptive interactions. Biochim Biophys Acta 1810:1052-8
Lin, Ko-Wei; Jen, Kai Yu; Suarez, Carlos Jose et al. (2010) Surfactant protein D-mediated decrease of allergen-induced inflammation is dependent upon CTLA4. J Immunol 184:6343-9
Planche, Tim; Agbenyega, Tsiri; Bedu-Addo, George et al. (2003) A prospective comparison of malaria with other severe diseases in African children: prognosis and optimization of management. Clin Infect Dis 37:890-7