Alveolization represents the final phase of lung development in which large primary alveolar spaces are partitioned into smaller air spaces by inward protrusions of septae derived from the alveolar walls. During alveolization, expansion of the vasculature involves the process of angiogenesis in which new vessels arise from preexisting ones. This suggests that molecules, such PECAM-1, which regulate endothelial cell activity required for angiogenesis are likely to be important for alveolization. Our hypothesis is that during lung development, angiogenic stimuli initiate PECAM- 1 dependent ligand interactions that trigger PECAM-1 tyrosine phosphorylation and an association of endothelial PECAM-1 with SHP-2. This facilitates the recruitment of SHP-2 to the membrane surface, where it mediates the dephosphorylation of focal adhesion proteins, leading to increased turnover of focal adhesions and enhanced endothelial cell motility. These PECAM-1 dependent activities facilitate efficient angiogenesis and thus alveolization.
Three specific aims are proposed:
Specific Aim 1. Characterize the effect of the loss of PECAM-1 on murine alveolization. The phenotype of alveolization (? retinoic acid treatment) in PECAM-1 null mice will be characterized at a morphological, cellular, and functional level by determination of (i) lung morphology (ii) lung physiology and (iii) lung endothelial cell content.
Specific Aim 2. Define the role of SHP-2 in mediating ? PECAM-1-dependent cell motility. Stable cell transfectants expressing PECAM-1 will be transduced with adenoviral vectors encoding one of three SHP-2 dominant negative constructs bearing mutations in the catalytic domain, the C-terminal domain that mediates interactions with scaffold proteins or in both regions. Transduced cells will be analyzed for (i) the number and distribution of focal adhesions; (ii) the occurrence of critical focal adhesion tyrosine phosphorylation events; and (iii) cell motility using established in vitro models of cell migration and tube formation.
Specific Aim 3. Determine the role of PECAM-1 tyrosine phosphorylation during in vivo angiogenesis and alveolization. Transgenic mice will be generated on the PECAM-null background that express in an endothelial-restricted manner, either wild type PECAM-1, or PECAM-1 in which Y663 and Y686 have been mutated. In vivo angiogenesis and alveolization will then be studied in these animals. These studies will further our understanding of molecular basis of alveolization and may provide insights into new approaches for regenerating functional alveoli in premature infants with bronchopulmonary dysplasia and adults with emphysema or fibrotic lung disease. ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL079090-02
Application #
6951477
Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Berberich, Mary Anne
Project Start
2004-09-30
Project End
2008-08-31
Budget Start
2005-09-01
Budget End
2006-08-31
Support Year
2
Fiscal Year
2005
Total Cost
$354,071
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Cui, Zheng; Liao, Jie; Cheong, Naeun et al. (2018) The Receptor for Hyaluronan-Mediated Motility (CD168) promotes inflammation and fibrosis after acute lung injury. Matrix Biol :
Bennett, Katherine M; Afanador, Maria D; Lal, Charitharth V et al. (2013) Ephrin-B2 reverse signaling increases ?5?1 integrin-mediated fibronectin deposition and reduces distal lung compliance. Am J Respir Cell Mol Biol 49:680-7
DeLisser, Horace M (2011) Modulators of endothelial cell filopodia: PECAM-1 joins the club. Cell Adh Migr 5:37-41
Zhu, Jing-Xu; Cao, Gaoyuan; Williams, James T et al. (2010) SHP-2 phosphatase activity is required for PECAM-1-dependent cell motility. Am J Physiol Cell Physiol 299:C854-65
Twarock, Sören; Tammi, Markku I; Savani, Rashmin C et al. (2010) Hyaluronan stabilizes focal adhesions, filopodia, and the proliferative phenotype in esophageal squamous carcinoma cells. J Biol Chem 285:23276-84
DeLisser, Horace; Liu, Yong; Desprez, Pierre-Yves et al. (2010) Vascular endothelial platelet endothelial cell adhesion molecule 1 (PECAM-1) regulates advanced metastatic progression. Proc Natl Acad Sci U S A 107:18616-21
Fehrenbach, Melane L; Cao, Gaoyuan; Williams, James T et al. (2009) Isolation of murine lung endothelial cells. Am J Physiol Lung Cell Mol Physiol 296:L1096-103
Zhang, Huayan; Garber, Samuel J; Cui, Zheng et al. (2009) The angiogenic factor midkine is regulated by dexamethasone and retinoic acid during alveolarization and in alveolar epithelial cells. Respir Res 10:77
Cao, Gaoyuan; Fehrenbach, Melane L; Williams, James T et al. (2009) Angiogenesis in platelet endothelial cell adhesion molecule-1-null mice. Am J Pathol 175:903-15
Delisser, Horace M (2007) Targeting PECAM-1 for anti-cancer therapy. Cancer Biol Ther 6:121-2

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