Functional Analysis of the Chemokine Receptor CCR3 on Airway Epithelial Cells

Abstract

The function of chemokine receptors on structural cells is only partially known. We previously reported the expression of a functional CCR3 receptor on airway epithelial cells (EC). We speculated that CCR3 might drive wound repair and expression of inflammatory genes in epithelium. The human airway EC lines BEAS-2B, 16-HBE, and primary bronchial EC were used to test the effect of in vitro challenge with the CCR3 ligands CCL11/eotaxin, CCL24/eotaxin-2, or CCL26/eotaxin-3 on 1) wound repair, using an established wound model; 2) cell proliferation and chemotaxis, using specific fluorometric assays; and 3) gene expression, using pathway-specific arrays for inflammatory and profibrotic cytokines, chemokines, and chemokine receptor genes. Agonist specificity was tested by cell pretreatment with an AstraZeneca CCR3 antagonist (10−8 – 10−6 M). CCL24 challenge significantly accelerated epithelial wound closure, with similar effects exerted by CCL11 and CCL26. This effect was time dependent, submaximal at 1 nM, and comparable in potency to epidermal growth factor. CCL24 induced a concentration-dependent increase in EC proliferation and chemotaxis, with significant effects observed at 10 nM. The AstraZeneca compound selectively inhibited these CCL24-mediated responses. CCL11 induced the up-regulation of several profibrogenic molecules such as fibroblast growth factor 1 and 5 and of several CC and CXC chemokines. Epithelial immunostaining for CCR3 was stronger in bronchial biopsies of asthmatics displaying marked inflammatory changes than in nondiseased samples. Epithelial CCR3 participates in key functions for wound repair, amplifies the expression of profibrogenic and chemokine transcripts, and appears up-regulated in inflamed asthmatic airways.

Chemokine receptors and their therapeutic opportunities in diseased lung: Far beyond leukocyte trafficking

“…Moreover, the interaction of CCR3 with its ligand CCL11/eotaxin led to tyrosine phosphorylation of cellular proteins (147). In addition, CCL11/eotaxin together with other CCR3 ligands, CCL24/eotaxin-2 and CCL26/eotaxin-3, were able to induce proliferation and migration of airway epithelial cells (9).…”

Transcriptome of Hypoxic Immature Dendritic Cells: Modulation of Chemokine/Receptor Expression

“…CCL26 belongs to the eotaxin group that recruits Th2 lymphocytes, basophiles, and eosinophils via CCR3 receptor. CCL26 is expressed by several tissue (43)(44)(45), and we show that iDCs are among them. Interestingly, this chemokine can antagonize the CCR2 receptor (38,43) and its down-regulation by hypoxia could be required to allow the response of Hi-DCs to CCR2 ligands.…”

CXCR4 regulates migration of lung alveolar epithelial cells through activation of Rac1 and matrix metalloproteinase-2

“…Chemokines are low-molecular-weight proteins that have been shown to involved in cell migration, proliferation, differentiation, and inflammation in asthma, chronic obstructive pulmonary disease, and acute lung injury (7,8,12,28,37,42). However, their role in ATII cell-mediated repair has not been extensively studied.…”

“…Chemokines have also been shown to control the expression of adhesion receptors on cells and, thereby, influence interactions with the extracellular matrix (ECM) (47). ATII cells have been shown to express the chemokine receptors CCR2, CCR3, CXCR2, and CXCR3 (7,12,46,57), and stimulation of CCR2 by its ligand monocyte chemoattractant protein 1 has been shown to stimulate repair of wounded cell monolayers. Mice lacking the CXCR4 gene or the gene for its ligand CXCL12 (stromal cell-derived factor 1␣) do not survive (40,55).…”