Allergic asthma is a chronic inflammatory disorder of the airways. There is good evidence that many of thefeatures of asthma, including airway remodeling (AR) are largely due to inappropriate activation of T cellsand consequent imbalance of Th1/Th2 cytokines and the recruitment if inflammatory cells includingmacrophages to the airway. However, the role of heparan sulfates (HS) in the modulation of airway allergicresponses and airway remodeling are poorly understood. Heparin and HS interact with various componentsof the inflammatory cascade in vitro, such as P- and L-selectins, inflammatory mediators, proteoglycans,growth factors cytokines and chemokines to mediate leukocyte migration, endothelial proliferation and tissueremodeling. However the role of endothelial and leukocyte expressed HS in allergic inflammation and ARhas never been determined. To study the significance of HS in AR, glucosaminyl N-deacetylase/N-sulfotransferase-1 (NDST1) was knocked out in endothelial cells (EC) and leukocytes using the Cre-loxPsystem. The NDST-1-deficient mice (NDST1f/fTie2Cre+) showed impaired inflammatory responses in multipletypes of assays in vitro and in vivo. Based on our preliminary observations that lack of NDST-1 in allergenchallengedmice leads to altered leukocyte trafficking, impaired macrophage but not eosinophil recruitment inthe airways, reduced expression of the Th2 cytokine IL-5, TGF-beta1 and AHR, along with diminished ECproliferation, we postulate that the targeted deficiency of NDST-1 will result in abrogation of the inflammatoryconditions associated with allergen-induced inflammation and AR. To examine this, two specific aims areproposed. In the first specific aim we will assess the role of HS biosynthetic enzyme NDST-1 in theexpression of Th2 cytokines, generation and recruitment of macrophages and macrophage progenitor cellsto the airways and trafficking of mononuclear cells within the pulmonary vascular bed in the remodeledairways of allergen mice. In this aim the ability of bone marrow derived CD34+ progenitors cells to interactwith murine lung EC in the context of HS expression will be examined in NDST1f/fTie2Cre+ mutant andNDST1f/fTie2Cre- wild type mice. In the second specific aim we will delineate the role of HS/NDST-1 inallergen-mediated AR and pulmonary angiogenesis associated with repetitive allergen challenge.Specifically, we will examine the role of HS/NDST-1 on the release of TGF-beta1, MMP-9, FGF-2 and VEGF by macrophages and other inflammatory cells and their effect on the cellular features of airway remodeling. Wewill also examine the role of NDST-1 and HS to modulate trafficking of inflammatory leukocytes withangiogenic blood vessels of the NDST-1 deficient and wild type mice exposed to repetitive allergenchallgenge. Overall we will attempt to delineate the functional importance of EC vs. leukocyte expressed HSby NDST-1 in airway remodeling and airway allergic inflammation.
Showing the most recent 10 out of 106 publications
