During erythropoiesis, maturing erythroblasts form adhesive interactions with extracellular matrix components and with other bone marrow cells in their local microenvironment. It is known that clusters of erythroblasts rely on such interactions for optimal cell maturation, but the precie role of the erythropoietic microenvironment in supporting and modulating erythroid maturation is unclear. Integrins in the cell membrane are the key mediators of erythroblast cell-cell and cell-matrix interactions. In addition to promoting adhesion interactions, integrins mediate bidirectional signaling (outside-in and inside-out) between the extracellular and intracellular environments of the erythroblast. Integrins are also important mediators of cytoskeletal reorganization, a process that is central to the structural changes occurring in the terminal stages of erythroid maturation. Here, we propose to measure the membrane dynamics of the major erythroblast integrins, define the molecular regulation of integrin-mediated erythroblast adhesion interactions, and characterize the links between integrin dynamics and cytoskeletal reorganization. We will also investigate the relationship between integrin-driven signaling and erythropoietin-driven signaling, which could work together to optimize erythropoiesis under homeostatic and/or stress conditions. Our ultimate goal is to understand the impact of integrin-dependent functions on erythropoiesis. Our laboratory is ideally suited to undertake these endeavors, having at our disposal multiple advanced, quantitative single-molecule and single-cell imaging techniques as well as expertise in multicolor flow cytometry and mouse models. Based on our preliminary data, we hypothesize that erythroblast integrin dynamics and signaling both modulate and are governed by erythroid maturation and that integrin-mediated events interact with erythropoietin-directed signaling in this process.
In Aim 1, we will characterize the membrane dynamics of integrins on the maturing erythroblast, define how such dynamics are controlled by ligand engagement and cytoskeletal reorganization, and elucidate the regulation of intracellular signaling pathways by these dynamics.
In Aim 2, we will characterize mechanisms of potential interaction between erythropoietin-dependent pathways and integrin-dependent pathways that regulate terminal erythroid maturation. Successful completion of this project will provide new insights into the mechanisms underlying erythroid development and may aid in the identification of novel targets for therapeutic intervention in disorders of erythropoiesis.

Public Health Relevance

/RELEVANCE Red blood cell development (erythropoiesis) occurs in the bone marrow and is governed by specific adhesive interactions between the maturing red cells and their local environment. By characterizing these adhesive interactions and the signaling networks that are activated by these interactions, this project proposes to fill a significant gap in the fundamental understanding of normal red blood cell development. Results from this research may lead to safer and more effective treatments for anemia, including improvements in the therapeutic use of erythropoietin and new and improved treatments for primary bone marrow diseases and chronic kidney disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL116327-04
Application #
8875744
Study Section
Special Emphasis Panel (ZHL1)
Program Officer
Hanspal, Manjit
Project Start
2012-09-26
Project End
2017-06-30
Budget Start
2015-07-01
Budget End
2017-06-30
Support Year
4
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Harvard Medical School
Department
Biochemistry
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
Cancedda, Corrado; Riviello, Robert; Wilson, Kim et al. (2017) Building Workforce Capacity Abroad While Strengthening Global Health Programs at Home: Participation of Seven Harvard-Affiliated Institutions in a Health Professional Training Initiative in Rwanda. Acad Med 92:649-658
Gera, Nidhi; Swanson, Kenneth D; Jin, Tian (2017) ?-Arrestin 1-dependent regulation of Rap2 is required for fMLP-stimulated chemotaxis in neutrophil-like HL-60 cells. J Leukoc Biol 101:239-251
Chiasson-MacKenzie, Christine; Morris, Zachary S; Baca, Quentin et al. (2015) NF2/Merlin mediates contact-dependent inhibition of EGFR mobility and internalization via cortical actomyosin. J Cell Biol 211:391-405
Gera, Nidhi; Yang, Aaron; Holtzman, Talia S et al. (2015) Tumor treating fields perturb the localization of septins and cause aberrant mitotic exit. PLoS One 10:e0125269
Reim, Natalia I; Kamil, Jeremy P; Wang, Depeng et al. (2013) Inactivation of retinoblastoma protein does not overcome the requirement for human cytomegalovirus UL97 in lamina disruption and nuclear egress. J Virol 87:5019-27
Alenghat, Francis J; Golan, David E (2013) Membrane protein dynamics and functional implications in mammalian cells. Curr Top Membr 72:89-120
Jin, Benjamin Y; Lin, Alison J; Golan, David E et al. (2012) MARCKS protein mediates hydrogen peroxide regulation of endothelial permeability. Proc Natl Acad Sci U S A 109:14864-9
Yang, Xiuwei H; Mirchev, Rossen; Deng, Xinyu et al. (2012) CD151 restricts the ?6 integrin diffusion mode. J Cell Sci 125:1478-87
Alenghat, Francis J; Baca, Quentin J; Rubin, Nooreen T et al. (2012) Macrophages require Skap2 and Sirp? for integrin-stimulated cytoskeletal rearrangement. J Cell Sci 125:5535-45