Emerging evidence suggests that chemokines play an important role at multiple steps during the induction of a pulmonary immune response, from the recruitment of dendritic cells (DC) to the lung, to the trafficking of antigen (Ag)-loaded DCs to the draining lymph nodes (LNs) to present the Ag to naive T cells. The receptors for certain chemokines such as MCP-1 (CCL2) and RANTES (CCLS) are highly expressed on immature DCs. RANTES was recently shown to induce cytokine and chemokine production in DCs. Our own preliminary studies show that both MCP-1 and RANTES influence lung DC function by modulating the expression of co-stimulatory molecules and cytokines in DCs and in the ability of DCs to induce the expression of subset-specific transcription factors such as T-bet (Th1-specific) and GATA-3 (Th2-specific) in CD4+ T cells. These observations are in line with previous reports that have implicated both MCP-1 and RANTES in lung inflammation. However, whether these chemokines can influence lung inflammation by modulating lung DC function and in turn T cell polarization in the local LNs has not been adequately explored at the present time. In this proposal, we will test the hypothesis that the chemokines MCP-1 and RANTES play important roles in lung inflammation by regulating DC function which in turn regulates T cell differentiation and function. To test this hypothesis we will:
Aim I. Characterize the effect of the chemokines MCP-1 and RANTES on lung DC function. The effects of MCP-1 and RANTES on immature lung DCs will be studied by assessment of i) antigen uptake, ii) cytokine and chemokine expression, iii) expression of toll-like receptors (TLRs) iv) the induction of co-stimulatory molecules, and v) the induction of cell survival in the presence or absence of soluble antigen or toll-like receptor (TLR) agonists.
Aim II. Determine the effect of the chemokines on lung DC function in vivo. Transgenic mice expressing MCP-1 or RANTES will be used to assess the effects of the chemokines on lung DC and T cell function in vivo. Mice will be subjected to a Th1- or a Th2-driven model of lung inflammation and the role of MCP-1 or RANTES will be determined using antagonists/neutralizing antibodies.
Aim III. Investigate chemokine-induced signaling pathways in DCs and the influence of chemokine-treated DCs on T cell activation and differentiation. The role of specific signaling pathways in chemokine-modulated DC function will be studied. Also, the effect of chemokine-treated DCs on T cell responses will be determined at various levels including expression of T cell activation markers, activation of signaling pathways, expression of transcription factors and cytokine production.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL060207-10
Application #
7325668
Study Section
Special Emphasis Panel (ZRG1-SSS-3 (02))
Program Officer
Noel, Patricia
Project Start
1998-04-01
Project End
2010-11-30
Budget Start
2007-12-01
Budget End
2010-11-30
Support Year
10
Fiscal Year
2008
Total Cost
$310,154
Indirect Cost
Name
University of Pittsburgh
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Krishnamoorthy, Nandini; Oriss, Timothy B; Paglia, Melissa et al. (2008) Activation of c-Kit in dendritic cells regulates T helper cell differentiation and allergic asthma. Nat Med 14:565-73

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