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.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL043331-16
Application #
7078617
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Massicot-Fisher, Judith
Project Start
1991-04-01
Project End
2008-05-31
Budget Start
2006-06-01
Budget End
2008-05-31
Support Year
16
Fiscal Year
2006
Total Cost
$411,119
Indirect Cost
Name
Yale University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
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Ramgolam, Vinod S; DeGregorio, Scott D; Rao, Gautham K et al. (2010) T cell LFA-1 engagement induces HuR-dependent cytokine mRNA stabilization through a Vav-1, Rac1/2, p38MAPK and MKK3 signaling cascade. PLoS One 5:e14450
Panattoni, Martina; Sanvito, Francesca; Basso, Veronica et al. (2008) Targeted inactivation of the COP9 signalosome impairs multiple stages of T cell development. J Exp Med 205:465-77
Savio, M G; Rotondo, G; Maglie, S et al. (2008) COP1D, an alternatively spliced constitutive photomorphogenic-1 (COP1) product, stabilizes UV stress-induced c-Jun through inhibition of full-length COP1. Oncogene 27:2401-11
Rao, Gautham K; Bender, Jeffrey R (2008) Rac, PAK, and eNOS ACTion. Circ Res 103:328-30
Molteni, Raffaella; Fabbri, Monica; Bender, Jeffrey R et al. (2006) Pathophysiology of leukocyte-tissue interactions. Curr Opin Cell Biol 18:491-8

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