Crosstalk between Mast Cells and Lung Fibroblasts Is Modified by Alveolar Extracellular Matrix and Influences Epithelial Migration.

Mast cells play an important role in asthma, however, the interactions between mast cells, fibroblasts and epithelial cells in idiopathic pulmonary fibrosis (IPF) are less known. The objectives were to investigate the effect of mast cells on fibroblast activity and migration of epithelial cells. Lung fibroblasts from IPF patients and healthy individuals were co-cultured with LAD2 mast cells or stimulated with the proteases tryptase and chymase. Human lung fibroblasts and mast cells were cultured on cell culture plastic plates or decellularized human lung tissue (scaffolds) to create a more physiological milieu by providing an alveolar extracellular matrix. Released mediators were analyzed and evaluated for effects on epithelial cell migration. Tryptase increased vascular endothelial growth factor (VEGF) release from fibroblasts, whereas co-culture with mast cells increased IL-6 and hepatocyte growth factor (HGF). Culture in scaffolds increased the release of VEGF compared to culture on plastic. Migration of epithelial cells was reduced by IL-6, while HGF and conditioned media from scaffold cultures promoted migration. In conclusion, mast cells and tryptase increased fibroblast release of mediators that influenced epithelial migration. These data indicate a role of mast cells and tryptase in the interplay between fibroblasts, epithelial cells and the alveolar extracellular matrix in health and lung disease.

Mast cells and mast cell tryptase enhance migration of human lung fibroblasts through protease-activated receptor 2.

BACKGROUND: Mast cells may activate fibroblasts and contribute to remodeling processes in the lung. However, the mechanism behind these actions needs to be further investigated. Fibroblasts are major regulators of on-going remodeling processes. Protease activated receptor 2 (PAR2) expressed by fibroblasts may be activated by serine proteases, such as the mast cell mediator tryptase. The objective in this study was to investigate the effects of mast cells and specifically mast cell tryptase on fibroblast migration and the role of PAR2 activation. METHODS: Human lung fibroblasts (HFL-1) were cultured together with human peripheral blood-derived mast cells or LAD2 mast cells and stimulated with either conditioned medium from LAD2 cells or tryptase. Analyses of immunological stimulation of mast cells by IgE/anti IgE in the co-culture system were also performed. The importance of PAR2 activation by mast cells and mast cell tryptase for the migratory effects of fibroblasts was investigated by pre-treatment with the PAR2 antagonist P2pal-18S. The expression of PAR2 was analyzed on fibroblasts and mast cells. RESULTS: The migratory capacity of HFL-1 cells was enhanced by blood-derived mast cells (p < 0.02), LAD2 cells (p < 0.001), conditioned medium (p < 0.05) and tryptase (p < 0.006). P2pal-18S decreased the induced migration caused by mast cells (p < 0.001) and tryptase (p < 0.001) and the expression of PAR2 was verified in HFL-1 cells. Mast cells immunologically stimulated with IgE/Anti IgE had no further effects on fibroblast migration. CONCLUSIONS: Mast cells and the mast cell mediator tryptase may have crucial roles in inducing lung fibroblast migration via PAR-2 activation, which may contribute to remodeling processes in chronic lung diseases.

VEGF synthesis is induced by prostacyclin and TGF-ß in distal lung fibroblasts from COPD patients and control subjects: Implications for pulmonary vascular remodelling.

BACKGROUND AND OBJECTIVE: Involvement of pulmonary vascular remodelling is a characteristic sign in COPD. Vascular mediators such as vascular endothelial growth factor (VEGF) and prostacyclin may regulate fibroblast activity. The objective was to study the synthesis of VEGF and interactions with prostacyclin and transforming growth factor (TGF)-ß1 in lung fibroblasts from patients with COPD and healthy control subjects. To further explore the autocrine role of synthesized VEGF on fibroblast activity, studies were performed in human lung fibroblasts (HFL-1). METHODS: Primary distal lung fibroblast cultures were established from healthy individuals and from COPD patients (GOLD stage IV). Lung fibroblasts were stimulated with the prostacyclin analogue iloprost and the profibrotic stimuli TGF-ß1 . VEGF synthesis was measured in the cell culture medium. Changes in proliferation rate, migration and synthesis of the extracellular matrix (ECM) proteins proteoglycans were analysed after stimulations with VEGF-A isoform 165 (VEGF165 ; 1-10 000 pg/mL) in HFL-1. RESULTS: Iloprost and TGF-ß1 significantly increased VEGF synthesis in both fibroblasts from COPD patients and control subjects. TGF-ß1 -induced VEGF synthesis was significantly reduced by the cyclooxygenase inhibitor indomethacin in fibroblasts from COPD patients. VEGF significantly increased proliferation rate and migration capacity in HFL-1. VEGF also significantly increased synthesis of the ECM proteins biglycan and perlecan. The VEGF receptors (VEGFR), VEGFR1, VEGFR2 and VEGFR3, were all expressed in primary lung fibroblasts and HFL-1. CONCLUSION: VEGF is synthesized in high amounts by distal lung fibroblasts and may have a crucial role in ongoing vascular remodelling processes in the distal lung compartments.

Dermatan sulfate is involved in the tumorigenic properties of esophagus squamous cell carcinoma.

Extracellular matrix, either produced by cancer cells or by cancer-associated fibroblasts, influences angiogenesis, invasion, and metastasis. Chondroitin/dermatan sulfate (CS/DS) proteoglycans, which occur both in the matrix and at the cell surface, play important roles in these processes. The unique feature that distinguishes DS from CS is the presence of iduronic acid (IdoA) in DS. Here, we report that CS/DS is increased five-fold in human biopsies of esophagus squamous cell carcinoma (ESCC), an aggressive tumor with poor prognosis, as compared with normal tissue. The main IdoA-producing enzyme, DS epimerase 1 (DS-epi1), together with the 6-O- and 4-O-sulfotransferases, were highly upregulated in ESCC biopsies. Importantly, CS/DS structure in patient tumors was significantly altered compared with normal tissue, as determined by sensitive mass spectrometry. To further understand the roles of IdoA in tumor development, DS-epi1 expression, and consequently IdoA content, was downregulated in ESCC cells. IdoA-deficient cells exhibited decreased migration and invasion capabilities in vitro, which was associated with reduced cellular binding of hepatocyte growth factor, inhibition of pERK-1/2 signaling, and deregulated actin cytoskeleton dynamics and focal adhesion formation. Our findings show that IdoA in DS influences tumorigenesis by affecting cancer cell behavior. Therefore, downregulation of IdoA by DS-epi1 inhibitors may represent a new anticancer therapy.