The Foreign Investigator (Fl) of this project has recently discovered that alphavbeta3 integrin in astrocytes is a receptor for Thy-1 and shown that treatment of astrocytes with Thy- 1 induces signaling linked to focal adhesions (FA) and stress fiber formation. FAs anchor stress fibers to the plasma membrane, contain multiple structural, signaling and adaptor molecules and are implicated in cell migration, growth and differentiation. Astrocytes change from stellate to fibroblast-like morphology upon brain damage and the GTPase RhoA has been implicated in these changes. Our preliminary data reveal that RhoA is implicated in Thy-1-induced focal adhesion formation in astrocytes. This collaborative grant is aimed at understanding how cell-cell interaction mediated by Thy-1 binding to integrin alphavBeta3 activates RhoA, whether integrin signaling triggered by Thy-1 binding stimulates cell migration and what are the signaling events occurring downstream from FAs. We will explore the possibility that Thy-1-astocyte interaction is mediated by two different domains on Thy-1, one binding integrins and one binding syndecans. We will look for possible guanine nucleotide exchange factors (GEFs) that may activate RhoA using dominant negative constructs of RhoA, which have high affinity for Rho GEFs. To study the effect of Thy-1- alphavBeta3 integrin interaction on cell migration we will use different wound healing assays currently in use in the PI's lab. We will also test whether changes in motility correlate with modulation of Rac 1 or Cdc42 activity, measured with pulldown assays. We will test the hypothesis that Thy-1 activated integrins trigger signaling events in astrocytes that are similar to those described in fibroblasts, with particular interest on the involvement of PI 3-kinase and MAP kinase pathways, given their known participation in cell migration and proliferation, respectively. Thus, in this proposal we will study the molecular response of astrocytes to Thy-1- alphavBeta3 integrin interaction in vitro. Learning about such changes should lead to a better understanding of """"""""astrogliosis,"""""""" a migratory and proliferative reaction of astrocytes to wounding, that creates an environment antagonistic to neuronal regeneration following brain injury.

Agency
National Institute of Health (NIH)
Institute
Fogarty International Center (FIC)
Type
Small Research Grants (R03)
Project #
5R03TW006024-03
Application #
6785988
Study Section
International and Cooperative Projects 1 Study Section (ICP)
Program Officer
Michels, Kathleen M
Project Start
2002-08-15
Project End
2005-06-30
Budget Start
2004-07-01
Budget End
2005-06-30
Support Year
3
Fiscal Year
2004
Total Cost
$40,320
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Avalos, Ana María; Valdivia, Alejandra D; Muñoz, Nicolás et al. (2009) Neuronal Thy-1 induces astrocyte adhesion by engaging syndecan-4 in a cooperative interaction with alphavbeta3 integrin that activates PKCalpha and RhoA. J Cell Sci 122:3462-71
Hermosilla, Tamara; Munoz, Daniel; Herrera-Molina, Rodrigo et al. (2008) Direct Thy-1/alphaVbeta3 integrin interaction mediates neuron to astrocyte communication. Biochim Biophys Acta 1783:1111-20
Tapia, J C; Torres, V A; Rodriguez, D A et al. (2006) Casein kinase 2 (CK2) increases survivin expression via enhanced beta-catenin-T cell factor/lymphoid enhancer binding factor-dependent transcription. Proc Natl Acad Sci U S A 103:15079-84
Kwon, Yoon-Jeoung; Perez, Paola; Aguilera, Sergio et al. (2006) Involvement of specific laminins and nidogens in the active remodeling of the basal lamina of labial salivary glands from patients with Sjogren's syndrome. Arthritis Rheum 54:3465-75
Choi, Jeongsuk; Leyton, Lisette; Nham, Sang-Uk (2005) Characterization of alphaX I-domain binding to Thy-1. Biochem Biophys Res Commun 331:557-61
Perez, Paola; Kwon, Yoon-Jeoung; Alliende, Cecilia et al. (2005) Increased acinar damage of salivary glands of patients with Sjogren's syndrome is paralleled by simultaneous imbalance of matrix metalloproteinase 3/tissue inhibitor of metalloproteinases 1 and matrix metalloproteinase 9/tissue inhibitor of metalloprotein Arthritis Rheum 52:2751-60
Quest, Andrew F G; Leyton, Lisette; Parraga, Mario (2004) Caveolins, caveolae, and lipid rafts in cellular transport, signaling, and disease. Biochem Cell Biol 82:129-44
Leyton, Lisette; Quest, Andrew F (2004) Supramolecular complex formation in cell signaling and disease: an update on a recurrent theme in cell life and death. Biol Res 37:29-43
Avalos, Ana Maria; Arthur, William T; Schneider, Pascal et al. (2004) Aggregation of integrins and RhoA activation are required for Thy-1-induced morphological changes in astrocytes. J Biol Chem 279:39139-45
Avalos, Ana Maria; Labra, Cecilia V; Quest, Andrew F G et al. (2002) Signaling triggered by Thy-1 interaction with beta 3 integrin on astrocytes is an essential step towards unraveling neuronal Thy-1 function. Biol Res 35:231-8