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Abstract

Grant Number: 5R01HL043331-15
Project Title: Molecular Models of Immune-mediated Vascular Injury
PI Information:NameEmailTitle
BENDER, JEFFREY R. jeffrey.bender@yale.edu PROFESSOR AND ASSOCIATE CHIEF

Abstract: DESCRIPTION (provided by applicant) Adhesion receptor-ligand interactions can influence vascularized organ allografts at multiple levels, including targeted trafficking of host leukocytes into the graft, costimulation of alloreactive T cells through leukocyte integrins, or directed killing of donor target cells by conjugate formation with cytotoxic, allospecific effector cells. We have previously demonstrated that LFA-1 (al B2) plays a critical role in lymphocyte-EC adhesion and lymphocyte migration, is dynamically regulated and, as a transmembrane signaling molecule, stabilizes Thi cytokine transcripts including IFN-g, TNF-a, and LL-2. This RNA stabilization is, in part, cytoskeleton dependent, is directed at modulation of transcript degradation through AU-rich target sequences, and requires the LFA-1 engagement-induced nuclear-to-cytoplasmic translocation of the critical RNA binding protein HuR. This has led to our overall hypothesis as follows: T cell co-activation, through LFA-1, drives actin cytoskeleton dependent modulation of HuR which, in turn, facilitates stabilization of labile T cell activation transcripts for multiple pro-inflammatory and pro-proliferative key effector molecules in acute and chronic vascular rejection. Specific proposals now include to (1) define proximal signaling components of LFA-1-mediated HuR translocation, by using actin cytoskeleton-disrupting agents and rho family GTPase mutants in T cell or LFA-1+ stable transfectant HuR translocation assays; (2) assess LFA-1-induced biochemical modifications on, and induced protein-protein interactions with, HuR in I cells, using phosphopeptide mapping and coimmunoprecipitation proteomics; (3) evaluate the effect of LFA-1 engagement on ARE-bearing transcripts encoding cell cycle regulatory molecules, including G1-, S- and G2-specific cyclins; and (4) test the role of HuR function in heterotopic and aortic allograft models in vivo with a T cell-specific, tetracycline regulable HuR knock out mouse. This work may provide insight into cellular and molecular triggers of allograft rejection, including those directed at the vasculature, and immune activation more broadly.

Public Health Relevance:
This Public Health Relevance is not available.

Thesaurus Terms:
atherosclerosis, cardiovascular injury, cell cell interaction, natural killer cell, transplantation immunology, vascular endothelium
RNA binding protein, T cell receptor, apoptosis, integrin, leukocyte activation /transformation, leukocyte adhesion molecule, protein protein interaction, protein structure function
clinical research, flow cytometry, fluorescence microscopy, gene targeting, genetically modified animal, human tissue, immunocytochemistry, immunofluorescence technique, immunoprecipitation, laboratory mouse, northern blotting, polymerase chain reaction, tissue /cell culture, western blotting

Institution: YALE UNIVERSITY
47 COLLEGE STREET, STE 203
NEW HAVEN, CT 065208047
Fiscal Year: 2005
Department: INTERNAL MEDICINE
Project Start: 01-APR-1991
Project End: 31-MAY-2007
ICD: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
IRG: SAT


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