HL-142. We submit this application in response to the recent NHLBI topic of special interest (TOSI) HL-142 titled Exosomes as paracrine signal mediators in cardiovascular, lung and blood disease (R01). Cardiac transplants are the best option for selected pediatric and adult patients with end-stage heart failure. Despite advances in immunosuppressive regimens, graft failure due to rejection and cardiac allograft vasculopathy remains a threat. Therefore, there is a need of new therapies to prevent/treat acute and chronic rejection of cardiac allografts, minimizing the use of immunosuppressive drugs and its side effects. This requires a deeper understanding of the mechanisms of allograft recognition and rejection. This application proposes to investigate the role of cell-to-cell communication via extracellular vesicles (EVs), in particular exosomes, in the allorecognition mechanisms that lead to cardiac graft rejection. Our preliminary studies indicate that the recipient immune system recognizes donor MHC molecules of cardiac allografts as non-self through cell-to-cell communication between donor and recipient leukocytes via exosome-like vesicles (and likely other EVs). Growing evidence indicates that leukocytes and other cell types transfer exosomes and other EVs carrying functional proteins, mRNAs and non-coding RNAs, which exert biological effects on target cells. Our application proposes to study the interaction between donor-derived EVs and the leukocytes of cardiac graft recipients, and the effects of donor EVs on the recipient immune system. The function of exosomes (and other EVs) in vivo remains an enigma. Our experimental approached has been designed to unveil the role of exosomes (and other EVs) in situ and in vivo. If successful, the results will provide one of the first evidences f the biological role of exosomes in vivo. This application will also challenge current paradigms on the mechanism of recognition of transplanted organs by T- and B-lymphocytes of the recipient. We propose the hypothesis that after heart transplantation, donor exosomes (and other EVs) function as paracrine mediators for passage and dissemination of donor MHC Ag and APC-stimulating signals to recipient APCs. Therefore, donor exosomes (and other EVs) are involved in elicitation and maintenance of acute and chronic rejection of cardiac transplants. We will test our hypothesis in a mouse model of heterotopic (abdomen) cardiac transplantation, in the following Specific Aims:
Aim 1 : Study the role of donor exosomes (and other EVs) in T-cell allo-recognition after cardiac transplantation, and Aim 2: Study the role of donor-derived exosomes (and other EVs) in elicitation and maintenance of B-cell immunity against cardiac allografts. Our long-term goal is to achieve a better understanding of the mechanisms of heart allograft rejection with the aim of providing new grounds for development of therapies and disease markers based on the biology of EVs.

Public Health Relevance

Development of novel therapies to prevent or treat rejection of cardiac allografts, minimizing the use of immunosuppressive drugs and their harmful side-effects, requires a deeper understanding of the mechanisms by which the immune system of the recipient recognizes the presence of the transplanted organ. Leukocytes of the immune system communicate by means of different extracellular vesicles, which include tiny exosomes secreted by cells, and bigger vesicles shed from the cell surface. Our preliminary studies indicate that cell-to-cell communication via passage of extracellular vesicles allows the immune system to recognize transplanted organs as non-self, which is the first step during elicitation of the anti- donor response that leads to transplant rejection. Our application proposes to study, for the first time, the interaction of these donor-derived extracellular vesicles (in particular exosomes) with leukocytes of the recipient in vivo. Our goal is to achieve a profound understanding of the mechanisms of transplant rejection, which will provide solutions to old questions in transplantation that still remain unanswered, and explore new grounds for development of novel therapeutic approaches.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL130191-01
Application #
9005947
Study Section
Special Emphasis Panel (ZRG1-IMM-H (02))
Program Officer
Wang, Lan-Hsiang
Project Start
2016-02-08
Project End
2020-01-31
Budget Start
2016-02-08
Budget End
2017-01-31
Support Year
1
Fiscal Year
2016
Total Cost
$378,520
Indirect Cost
$128,520
Name
University of Pittsburgh
Department
Surgery
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Ono, Yoshihiro; Perez-Gutierrez, Angelica; Nakao, Toshimasa et al. (2018) Graft-infiltrating PD-L1hi cross-dressed dendritic cells regulate antidonor T cell responses in mouse liver transplant tolerance. Hepatology 67:1499-1515
Zeng, Furong; Morelli, Adrian E (2018) Extracellular vesicle-mediated MHC cross-dressing in immune homeostasis, transplantation, infectious diseases, and cancer. Semin Immunopathol 40:477-490
Yang, Mu-Qing; Du, Qiang; Goswami, Julie et al. (2018) Interferon regulatory factor 1-Rab27a regulated extracellular vesicles promote liver ischemia/reperfusion injury. Hepatology 67:1056-1070
Zettel, Kent; Korff, Sebastian; Zamora, Ruben et al. (2017) Toll-Like Receptor 4 on both Myeloid Cells and Dendritic Cells Is Required for Systemic Inflammation and Organ Damage after Hemorrhagic Shock with Tissue Trauma in Mice. Front Immunol 8:1672
Morelli, Adrian E; Bracamonte-Baran, William; Burlingham, William J (2017) Donor-derived exosomes: the trick behind the semidirect pathway of allorecognition. Curr Opin Organ Transplant 22:46-54
Morelli, Adrian E (2017) Exosomes: From Cell Debris to Potential Biomarkers in Transplantation. Transplantation 101:2275-2276
Ezzelarab, M B; Raich-Regue, D; Lu, L et al. (2017) Renal Allograft Survival in Nonhuman Primates Infused With Donor Antigen-Pulsed Autologous Regulatory Dendritic Cells. Am J Transplant 17:1476-1489
Liu, Quan; Rojas-Canales, Darling M; Divito, Sherrie J et al. (2016) Donor dendritic cell-derived exosomes promote allograft-targeting immune response. J Clin Invest 126:2805-20
Baldwin 3rd, W M; Morelli, A E (2016) Strategically Altering the Balance of Macrophage Subpopulations to Inhibit Chronic Rejection. Am J Transplant 16:2510-1
Zhuang, Quan; Liu, Quan; Divito, Sherrie J et al. (2016) Graft-infiltrating host dendritic cells play a key role in organ transplant rejection. Nat Commun 7:12623

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