This is a modified and resubmitted application based on the hypothesis that the erythrocyte membrane proteins Lutheran (Lu) and LW function in cell-cell and cell-extracellular matrix interactions in the bone marrow. Based on preliminary results that LW is expressed early in erythropoiesis and binds to alpha4beta1 and alphav integrins, the application proposes that LW may mediate interactions of erythroblasts with one another and with macrophages to form the erythroblastic island structure. Lu glycoprotein is known to bind laminin and the applicant has obtained evidence that it is not expressed until late in erythropoiesis. The timing of the appearance of Lu on the cell surface suggests a role in erythroblast enucleation or release of precursors from the marrow. Additionally, preliminary results indicate that Lu and LW may contribute to the pathophysiology of sickle cell disease by mediating the adhesion of sickle red cells to vascular endothelial cells. To test these hypotheses the applicant proposes to: (1) Generate knockout mice lacking the murine homologues of Lu and LW by homologous recombination. (2) Characterize the structure-function of Lu and LW by identifying the domains of Lu and LW involved in ligand binding and employing domain-deletion mutants and site-directed mutagenesis; developing blocking antibodies and peptides and testing their effects on macrophage-erythroblast and erythroblast interactions, erythroid progenitor cell growth, and nuclear extrusion using in vitro assays and micromechanical techniques; and by analyzing erythropoiesis in the knockout mice including the degree of ineffective erythropoiesis, capacity to form erythroblastic islands, process of erythroblast enucleation, and ability to generate reticulocytes during stress erythropoiesis. (3) Examine roles of Lu and LW in sickle cell disease by studying the effect on vascular blood flow of infusing transgenic/knockout sickle mice with antibodies directed against Lu and LW which block adhesion of sickle red cells to endothelial cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK056267-02
Application #
6381616
Study Section
Hematology Subcommittee 2 (HEM)
Program Officer
Badman, David G
Project Start
2000-09-01
Project End
2004-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
2
Fiscal Year
2001
Total Cost
$313,435
Indirect Cost
Name
Lawrence Berkeley National Laboratory
Department
Biology
Type
Organized Research Units
DUNS #
078576738
City
Berkeley
State
CA
Country
United States
Zip Code
94720
Mohandas, Narla; Chasis, Joel Anne (2010) The erythroid niche: molecular processes occurring within erythroblastic islands. Transfus Clin Biol 17:110-1
Salomao, Marcela; Chen, Ke; Villalobos, Jonathan et al. (2010) Hereditary spherocytosis and hereditary elliptocytosis: aberrant protein sorting during erythroblast enucleation. Blood 116:267-9
Liu, Jing; Guo, Xinhua; Mohandas, Narla et al. (2010) Membrane remodeling during reticulocyte maturation. Blood 115:2021-7
Popova, Evgenya Y; Krauss, Sharon Wald; Short, Sarah A et al. (2009) Chromatin condensation in terminally differentiating mouse erythroblasts does not involve special architectural proteins but depends on histone deacetylation. Chromosome Res 17:47-64
Chasis, Joel Anne; Mohandas, Narla (2008) Erythroblastic islands: niches for erythropoiesis. Blood 112:470-8
An, Xiuli; Gauthier, Emilie; Zhang, Xihui et al. (2008) Adhesive activity of Lu glycoproteins is regulated by interaction with spectrin. Blood 112:5212-8
Mankelow, Tosti J; Burton, Nicholas; Stefansdottir, Fanney O et al. (2007) The Laminin 511/521-binding site on the Lutheran blood group glycoprotein is located at the flexible junction of Ig domains 2 and 3. Blood 110:3398-406
Chasis, Joel Anne (2006) Erythroblastic islands: specialized microenvironmental niches for erythropoiesis. Curr Opin Hematol 13:137-41
Kaul, Dhananjay K; Liu, Xiao-du; Zhang, Xiaoqin et al. (2006) Peptides based on alphaV-binding domains of erythrocyte ICAM-4 inhibit sickle red cell-endothelial interactions and vaso-occlusion in the microcirculation. Am J Physiol Cell Physiol 291:C922-30
Lee, Gloria; Lo, Annie; Short, Sarah A et al. (2006) Targeted gene deletion demonstrates that the cell adhesion molecule ICAM-4 is critical for erythroblastic island formation. Blood 108:2064-71

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