The CC chemokine eotaxin/CCL11 has a selective profibrogenic effect on human lung fibroblasts.
BACKGROUND
Eotaxin/CCL11 plays an important role in asthma. It acts through the chemokine receptor CCR3 expressed on hematopoietic and nonhematopoietic cells in the lung.


OBJECTIVE
To determine whether eotaxin/CCL11 modulates lung and bronchial fibroblast properties and thereby might contribute to airway remodeling.


METHODS
CCR3 expression was characterized on a lung fibroblast line (MRC-5; flow cytometry, fluorescent microscopy, RT-PCR, and Northern blotting), on primary bronchial fibroblasts (flow cytometry), and on fibroblasts in human lung tissue (confocal laser microscopy). The effects of eotaxin/CCL11 on lung fibroblast migration (Boyden chamber), proliferation (tritiated thymidine incorporation), alpha-smooth muscle actin expression (ELISA), 3-dimensional collagen gel contraction (floating gel), pro-alpha1(I) collagen mRNA (Northern blotting), total collagen synthesis (tritiated proline incorporation), matrix metalloproteinase activity (gelatin zymography), and TGF-beta(1) release (ELISA) were evaluated. The contribution of eotaxin/CCL11/CCR3 binding on lung fibroblasts was also investigated by neutralizing experiments.


RESULTS
CCR3 is constitutively expressed in cultured lung and primary bronchial fibroblasts and colocalizes with specific surface markers for human fibroblasts in lung tissue. Eotaxin/CCL11 selectively modulates fibroblast activities by increasing their proliferation, matrix metalloproteinase 2 activity, and collagen synthesis but not their differentiation into myofibroblasts, contractility in collagen gel, or TGF-beta(1) release. Eotaxin/CCL11 enhances migration of lung fibroblasts in response to nonspecific chemoattractants, and this effect is completely inhibited by anti-CCR3-neutralizing antibodies.


CONCLUSIONS
These data demonstrate that eotaxin/CCL11 has a direct and selective profibrogenic effect on lung and bronchial fibroblasts, providing a novel mechanism whereby eotaxin/CCL11 can participate in airway remodeling in asthma.
Puxeddu
Ilaria
I
Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
Bader
Reem
R
Piliponsky
Adrian Martin
AM
Reich
Reuven
R
Levi-Schaffer
Francesca
F
Berkman
Neville
N
D002454:Cell Differentiation; D049109:Cell Proliferation; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000502:physiology*; D002633:Chemotaxis; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008875:Middle Aged; D011498:Protein Precursors / Q000235:genetics; D011658:Pulmonary Fibrosis / Q000209:etiology*; D012333:RNA, Messenger / Q000032:analysis; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000032:analysis / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
C515456:CCL11 protein, human; C515350:CCR3 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D011498:Protein Precursors; D012333:RNA, Messenger; D054397:Receptors, CCR3; D019707:Receptors, Chemokine; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003094:Collagen; D020778:Matrix Metalloproteinase 2