Combination of glycopyrronium and indacaterol inhibits carbachol-induced ERK5 signal in fibrotic processes.

BACKGROUND: Airway fibrosis is one of the pathological features of chronic obstructive pulmonary disease (COPD), and recent studies revealed that acetylcholine plays an important role in the development of airway remodeling by stimulating proliferation and collagen synthesis of lung fibroblasts. This study was designed to examine the effects of a long-acting muscarinic receptor antagonist (LAMA) glycopyrronium and a long-acting ß2 adrenergic receptor agonist (LABA) indacaterol on acetylcholine-mediated fibrotic responses in lung fibroblasts. METHODS: After carbachol (CCh) or transforming growth factor-ß1 (TGF-ß1) exposure, the response to glycopyrronium and indacaterol was determined in vitro in fibroblasts isolated from mild-to-moderate COPD lung tissue. The ability of fibroblasts to mediate the contraction of collagen gels was assessed. The expression of α-smooth muscle actin (α-SMA) and the phosphorylation of extracellular-signal-regulated kinase 5 (ERK5) were determined by immunoblot. TGF-ß1 was quantified by ELISA and acetylcholine was quantified by liquid chromatography tandem-mass spectrometry. RESULTS: CCh stimulated fibroblast-mediated collagen gel contraction and α-SMA expression and TGF-ß1 release by fibroblasts. Blockade of autocrine TGF-ß1 attenuated CCh-mediated fibrotic responses, while TGF-ß1 did not stimulate acetylcholine release. Glycopyrronium plus indacaterol significantly attenuated CCh- and TGF-ß1-mediated fibrotic responses through inhibition of ERK5 phosphorylation. Notably, the magnitudes of CCh- and TGF-ß1-stimulated gel contraction, CCh-induced TGF-ß1 release, and ERK5 phosphorylation were greater in fibroblasts isolated from COPD subjects than in those from non-smokers. CONCLUSIONS: CCh induced TGF-ß1 self-sustaining signaling loops by potentiating ERK5 signaling and promoted myofibroblast activity. This autocrine signaling mechanism may be an attractive therapeutic target to block the fibrotic response, which was modulated by the combination of glycopyrronium and indacaterol.

Oncostatin M modulates fibroblast function via signal transducers and activators of transcription proteins-3.

Oncostatin M (OSM), an inflammatory cytokine of the interleukin-6 (IL-6) superfamily, plays a key role in various biological processes such as modulation of extracellular matrix (ECM), cell proliferation, cell survival, and induction of inflammation. It has been reported that OSM was increased in asthma and pulmonary fibrosis, and thus OSM may play a role in airway remodeling and the development of lung parenchymal fibrosis. Recruitment of lung fibroblasts to the sites of airway injury and subsequent differentiation into myofibroblasts is believed to contribute to excess ECM deposition. In the current study, we assessed the ability of OSM to modulate fibroblast collagen gel contraction, migration toward fibronectin, and expression of α-smooth muscle actin (α-SMA). We demonstrated that OSM augments gel contraction, chemotaxis, and α-SMA expression. OSM-augmented fibroblast chemotaxis was mediated by the signal transducer and activator of transcription (STAT3) and p38 mitogen-activated protein kinase, while augmentation on gel contraction and α-SMA expression was mediated by STAT3. Neither transforming growth factor-ß1 nor PGE2 was involved in mediating OSM effect on the cells. The Th2 cytokines IL-4 and IL-13, which also are believed to play an important role in promoting lung fibrosis and airway remodeling, act through STAT3, and we demonstrated the potential for additive effects of OSM with IL-4 and IL-13. The present study supports the concept that OSM may contribute to tissue remodeling, which may be additive with IL-4 or IL-13. Blockade of OSM or OSM-mediated STAT3 signaling could be a therapeutic target to regulate lung fibrotic mechanisms.