Date: Sunday, May 3, 2015
Session Time: 5:30pm-6:30pm
Presentation Time: 5:30pm-6:30pm
Location: Exhibit Hall E
Purpose: Dendritic cells (DCs) are key players in both innate and adaptive immunity, as well as in immune tolerance. The mammalian target of rapamycin (mTOR) pathway has been proven to play essential roles in DC differentiation and function. We hereby attempted to compare the DC tolerogenicity induced by the mTOR complex 1 (mTORC1) inhibitor rapamycin (RAPA) and the ATP-competitive dual mTOR kinase inhibitor AZD8055 (AZD), and to explore the target protein pathways regulated by mTORC1 and 2, respectively.
Methods: DCs were propagated from C57BL/6 mouse bone marrow and differentiated in the presence of GM-CSF and IL-4 with either RAPA (RAPA-DCs) or AZD (AZD-DCs). The phenotype and allo-stimulatory activity were characterized. The quantitative proteomics analysis using isobaric tags for relative and absolute quantitation (iTRAQ) labeling and LC-MS/MS was used to explore differentially expressed proteins between the AZD and RAPA group.
Results: RAPA (1.25nM) and AZD (10nM) achieved comparable inhibition of mTORC1 downstream proteins, while only AZD inhibited mTORC2 pathway. Both RAPA and AZD effectively induced DC tolerogenicity, while AZD-DCs were more potent in inducing allogeneic T cell hypo-responsiveness and more Foxp3+ regulatory T cells. 150 proteins were found over-expressed while 107 proteins were under-expressed in the AZD treated DCs compared with the RAPA group using iTRAQ. Heat map analysis was performed and Function Enriched Interaction Network was built to show how those proteins were enriched and how enriched clusters were interacted with each other. Besides, several hub proteins were identified by the protein interaction network, which may account for the phenotypical and functional difference between two groups. By comparing the protein expression profiles, groups of differentially expressed proteins related to important biological processes of DCs were identifed. In particular, we confirmed several members of the lysosome pathway (β-hexosaminidase, β-glucuronidase, β-galactosidase, Napsa, Gm2a) might orchestrate DC differentiation and function.
Conclusions: The ATP competitive mTOR inhibitor AZD induces a unique panel of proteins in DCs compared to the classic mTOR inhibitor RAPA, which may provide novel mechanistic insights into DC tolerogenicity.
To cite this abstract in AMA style:Ma T, Pei Y, Han Y, Tao R. Proteomic Study Identified a Distinct Panel of Protein Expression in the ATP-Competitive MTOR Kinase Inhibitor Conditioned Dendritic Cells Compared to Rapamycin [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/proteomic-study-identified-a-distinct-panel-of-protein-expression-in-the-atp-competitive-mtor-kinase-inhibitor-conditioned-dendritic-cells-compared-to-rapamycin/. Accessed December 3, 2020.
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