Inflammation is a significant contributor to cardiovascular disease and related pathophysiological processes including stroke, hypertension, atherosclerosis, diabetes-metabolic syndrome. The activation and recruitment of effector T cell subsets into tissues is a highly regulated process that is dependent upon adhesive interactions between T cell subsets and the endothelium lining the vascularture. Therefore, our overall goal is to gain a better understanding of the mechanisms that regulate CD4+ T cell subset recruitment to sites of immune-mediated inflammation. Based on our exciting preliminary data and recent publication, we hypothesize that CD47 plays an important role in leukocyte ?1 and ?2 integrin adhesive functions by regulating the expression of high affinity conformations. By virtue of its effect on LFA-1 and VLA-4 integrin adhesive function and its well-documented role in immune cell homeostasis, CD47 and its ligand SIRP? play a critical role in multiple steps (arrest and migration) in the inflammatory response.
The specific aims will determine the molecular mechanisms and underlying structural basis of CD47 regulation of T cell LFA-1 and VLA-4 adhesive function and its role in T effector cell functions. We propose complementary and well-characterized in vitro cell culture systems and novel CyTOF mass spectroscopy technology to dissect the biochemical and molecular signaling pathways used by CD47 in human and murine immune cells to regulate integrin function. Specifically, Specific Aim 1 will employ recently developed single cell mass spectrometry (CyTOF mass spectrometry) and standard biochemical assays to interrogate intracellular signaling pathways in CD47-/- T cells to identify defects that cause impaired integrin activation in CD47-/- leukocytes. Up to 40 cell-surface molecules, intracellular signaling molecules and mediators (cytokines) can be measured in a single sample using CyTOF to provide much more information about cell phenotypes at a single-cell level.
Specific Aim 2 will address whether in trans CD47 ligands, Signal Regulatory Protein (SIRP)?, and SIRP?, and the secreted extracellular matrix protein, thrombospondin-1, affect CD47 in cis regulation of LFA-1 and VLA4 function during T cell recruitment.
In Specific Aim 3 we propose to determine the residues in CD47 that interact with ?2 integrins, which may provide guidance for designing novel and innovative therapeutic target(s), and identify biological reagents that impair these interactions. These approaches and our collaborations with established investigators will generate novel insights into CD47 regulation of integrin activation and adhesive functions in T cell trafficking.
Proper regulation of T effector lymphocyte recruitment is crucial to host defense. If T effector cell recruitment becomes dysregulated and excessive, this can result in development of chronic inflammation leading to autoimmune diseases, atherosclerosis, stroke, and hypertension. This project investigates the role of CD47 and its ligands in regulating trafficking of T and immune cell homeostasis in in vivo and in vitro models of inflammation.
| Folco, Eduardo J; Mawson, Thomas L; Vromman, Amélie et al. (2018) Neutrophil Extracellular Traps Induce Endothelial Cell Activation and Tissue Factor Production Through Interleukin-1? and Cathepsin G. Arterioscler Thromb Vasc Biol 38:1901-1912 |
| Miyabe, Yoshishige; Miyabe, Chie; Murooka, Thomas T et al. (2017) Complement C5a Receptor is the Key Initiator of Neutrophil Adhesion Igniting Immune Complex-induced Arthritis. Sci Immunol 2: |
| Azcutia, Veronica; Bassil, Ribal; Herter, Jan M et al. (2017) Defects in CD4+ T cell LFA-1 integrin-dependent adhesion and proliferation protect Cd47-/- mice from EAE. J Leukoc Biol 101:493-505 |
