Simultaneous stimulation with TGF-ß1 and TNF-α induces epithelial mesenchymal transition in bronchial epithelial cells.

BACKGROUND: Airway remodeling is an important feature of chronic airway disease, but the mechanisms involved remain unclear. Recently, epithelial mesenchymal transition (EMT) was reported to be associated with tissue fibrosis. TGF-ß1, which is a potent inducer of EMT, is thought to be related to the pathogenesis of airway remodeling. We investigated whether TGF-ß1 and/or TNF-α induce EMT in bronchial epithelial cells. METHODS: Cultured BEAS-2B cells and primary normal human bronchial epithelial cells (NHBE) were treated with TGF-ß1 and/or TNF-α. Morphological changes and the expression of EMT-related markers were evaluated by immunocytochemical staining. Expressions of EMT-related markers, extracellular matrix (ECM) components (collagen type I and versican), and TGF-ß receptors I, II, and III were analyzed by quantitative RT-PCR. Migration was evaluated using the Boyden chamber technique. RESULTS: The TGF-ß1-induced EMT in BEAS-2B cells was demonstrated on the basis of morphological changes and the downregulation of E-cadherin. Costimulation with TNF-α enhanced the TGF-ß1-induced morphological changes and increased vimentin expression. Treatment with TGF-ß1 increased the expression of collagen type I and versican. EMT induced with TGF-ß1 plus TNF-α promoted cell migration. Stimulation of NHBE with TGF-ß1 led to EMT. CONCLUSION: TGF-ß1 induced EMT in BEAS-2B cells, and costimulation with TNF-α enhanced the EMT. As a result of the EMT process, BEAS-2B cells acquired functions of mesenchymal cells. In addition, TGF-ß1 treatment induced EMT in NHBE as shown by changes in EMT-related markers. Bronchial epithelial cells might contribute to airway remodeling through EMT.

Tumor necrosis factor-alpha enhances both epithelial-mesenchymal transition and cell contraction induced in A549 human alveolar epithelial cells by transforming growth factor-beta1.

Recently, epithelial-mesenchymal transition (EMT) has been reported to contribute to tissue fibrosis through enhanced transforming growth factor (TGF)-beta1 signaling. Tumor necrosis factor (TNF)-alpha has also been implicated in tissue fibrosis. Therefore, the authors investigated whether TNF-alpha affected TGF-beta1-induced EMT. Cultured alveolar epithelial cells (A549 cells) were stimulated with TGF-beta1 (5 ng/mL), with/without TNF-alpha (10 ng/mL). TGF-beta1 induced EMT of A549 cells, with loss of E-cadherin and acquisition of vimentin. Combination of TNF-alpha with TGF-beta1 enhanced EMT, causing morphological changes, while quantitative polymerase chain reaction (PCR) showed suppression of E-cadherin mRNA and expression of vimentin mRNA. In addition, the gel contraction method revealed that cells that had undergone EMT acquired cell contractility, which is a feature of mesenchymal cells. Stimulation with TGF-beta1 induced cell contraction, as did TNF-alpha. Moreover, costimulation with TGF-beta1 and TNF-alpha enhanced the cell contraction. Although IFN-gamma suppressed spontaneous cell contraction, it did not suppress cell contraction, which was induced by TGF-beta1. In conclusion, TNF-alpha enhances not only EMT but also cell contraction induced by TGF-beta1. EMT might contribute to tissue fibrosis through induction of cell contraction.

Histamine stimulates human lung fibroblast migration.

Histamine is a potent mediator in allergic inflammatory processes and is released by basophils and mast cells. The aim of this study was to investigate the effect of histamine on in vitro migration of human fetal lung fibroblasts (HFL-1) to human plasma fibronectin (HFn), a chemoattractant. Using the blindwell chamber technique, histamine alone had no chemotactic activity. However, histamine augmented HFn-induced HFL-1 migration at concentrations ranging between 0 and 10(-7) M (290.6 +/- 20.8%) (P < 0.05). The concentration-response was bell-shaped. The effect of histamine increased with time. The stimulatory effect of histamine on HFL-1 migration was inhibited by an H4 receptor antagonist, JNJ7777120 (10(-5) M). Histamine's effect was also inhibited by pertussis toxin (50 ng/ml), showing that the effect was mediated by the H4 receptor. This study demonstrated that histamine has the potential to stimulate human lung fibroblast migration, and thus may contribute to regulation of wound healing and the development of fibrotic disorders of the lung.

Procaterol inhibits lung fibroblast migration.

Fibroblasts are important cells that are involved in modulation of fibrosis after injuries. In some uncontrollable inflammatory processes, excess fibroblasts migrate around the small airway. The pathogenesis of chronic obstructive pulmonary disease is related to fibrosis around the small airways. The aim of the current study was to investigate the effect of procaterol, a second-generation beta (2)-agonist, on migration of human fetal lung fibroblasts (HFL-1) induced by human plasma fibronectin (HFn). Using the blindwell chamber technique, 10(-8) M procaterol inhibited migration of HFL-1 (control, 100%; 10(-8) M, 73.2 +/- 4.9%; n = 6, p < 0.05). The inhibitory effect of procaterol was concentration-dependent. Although a beta 2-receptor inhibitor, ICI 181551, blocked the inhibitory effect of procaterol, a beta 1-receptor inhibitor, atenolol, did not. Because a cyclic AMP-dependent protein kinase (PKA) inhibitor, KT5720, blocked the effect of procaterol, the cyclic AMP-PKA pathway may be involved in the migration inhibitory process. Procaterol, which is prescribed mainly for treatment of bronchial asthma, might be a useful drug for inhibiting lung fibrosis following injuries to the lung.

Clarithromycin inhibits fibroblast migration.

UNLABELLED: The aim of the current study was to investigate the effect of 14-membered ring macrolide clarithromycin (CAM) on migration induced by human plasma fibronectin (HFn) or on contraction of human fetal lung fibroblasts (HFL-1). METHODS AND RESULTS: Using the blindwell chamber technique, CAM (10(-5) M) inhibited the migration of HFL-1 60.2+/-4.0% (p<0.05). Other antibiotics, such as ampicillin, minocycline or azithromycin had no effects on HFL-1 migration. The effect of CAM was concentration dependent. HFL-1 migration, stimulated by TXA(2) analog was also inhibited by CAM. Clarithromycin had no effect on HFL-1 mediated gel contraction that was another function of fibroblast at the wound area. CONCLUSIONS: Clarithromycin may contribute to the regulation of the wound healing response following injury by inhibiting fibroblast migration. These results could represent the therapeutic benefits of CAM.