Idiopathic pulmonary fibrosis fibroblasts migrate and proliferate to CC chemokine ligand 21.

Idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP) is the severest form of idiopathic interstitial pneumonia for which therapeutic targets are needed. Surgical lung biopsy specimens from IPF/UIP patients exhibit focal expression of CC chemokine receptor (CCR) 7, but the identity of these CCR7-positive cells is unknown. The purpose of the present study was to examine the functional and signalling significance of CCR7 expression of primary fibroblasts grown from IPF/UIP and normal surgical lung biopsy specimens. Primary fibroblasts were cultured from surgical lung biopsy specimens from IPF/UIP and normal patients. Fibroblasts treated with or without CC chemokine ligand (CCL) 21 were analysed for functional, transcriptional and proteomic differences using immunocytochemical analysis, gene arrays, Taqman real-time PCR, and migration, proliferation and Western blot assays. CCR7 was expressed by IPF/UIP fibroblasts, but not normal fibroblasts. IPF/UIP fibroblasts, but not normal fibroblasts, showed significant migratory and proliferative responses when exposed to CCL21, which were inhibited by pertussis toxin or neutralising antibodies to CCR7. Exposure of IPF/UIP fibroblasts to CCL21 altered the phosphorylation status of mitogen-activated protein kinase kinase 1/2, extracellular signal-regulated kinase 1/2 and ribosomal S6 kinase (90 kDa) in these cells; this was abrogated by pertussis toxin or CCR7-specific small interfering RNA. Together, these data demonstrate that CC chemokine ligand 21 modulates the functional properties of idiopathic pulmonary fibrosis/usual interstitial pneumonia fibroblasts, but not normal fibroblasts.

Focal interstitial CC chemokine receptor 7 (CCR7) expression in idiopathic interstitial pneumonia.

BACKGROUND/AIMS: Idiopathic interstitial pneumonias (IIPs) are a diverse grouping of chronic pulmonary diseases characterised by varying degrees of pulmonary fibrosis. The triggers of the fibroproliferative process in IIP remain enigmatic but recent attention has been directed towards chemokine involvement in this process. METHODS: The expression of two chemokine receptors, CCR7 and CXCR4, and their respective ligands, CCL19, CCL21, and CXCL12, were examined in surgical lung biopsies (SLBs) from patients with IIP. Transcript and protein expression of these receptors and their ligands was compared with that detected in histologically normal margin SLBs. RESULTS: CCR7 and CXCR4 were detected by gene array and real time polymerase chain reaction analysis and CCR7, but not CXCR4, expression was significantly raised in usual interstitial pneumonia (UIP) relative to biopsies from patients diagnosed with non-specific interstitial pneumonia (NSIP) or respiratory bronchiolitis/interstitial lung disease (RBILD). CCR7 protein was expressed in interstitial areas of all upper and lower lobe UIP SLBs analysed. CCR7 expression was present in 50% of NSIP SLBs, and CCR7 was restricted to blood vessels and mononuclear cells in 75% of RBILD SLBs. Immune cell specific CXCR4 expression was seen in IIP and normal margin biopsies. CCR7 positive areas in UIP biopsies were concomitantly positive for CD45 (the leucocyte common antigen) but CCR7 positive areas in all IIP SLBs lacked the haemopoietic stem cell antigen CD34, collagen 1, and alpha smooth muscle actin. CONCLUSION: This molecular and immunohistochemical analysis showed that IIPs are associated with abnormal CCR7 transcript and protein expression.