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Glycogen synthase kinase‐3 ( GSK ‐3) regulates TGF ‐β 1 ‐induced differentiation of pulmonary fibroblasts
Author(s) -
Baarsma Hoeke A,
Engelbertink Lilian HJM,
Hees Lonneke J,
Menzen Mark H,
Meurs Herman,
Timens Wim,
Postma Dirkje S,
Kerstjens Huib AM,
Gosens Reinoud
Publication year - 2013
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.12098
Subject(s) - myofibroblast , fibronectin , gsk 3 , microbiology and biotechnology , smad , gsk3b , pulmonary fibrosis , biology , fibroblast , extracellular matrix , transforming growth factor , chemistry , signal transduction , fibrosis , cancer research , medicine , cell culture , genetics
Background Chronic lung diseases such as asthma, COPD and pulmonary fibrosis are characterized by abnormal extracellular matrix ( ECM ) turnover. TGF ‐β is a key mediator stimulating ECM production by recruiting and activating lung fibroblasts and initiating their differentiation process into more active myofibroblasts. Glycogen synthase kinase‐3 ( GSK ‐3) regulates various intracellular signalling pathways; its role in TGF ‐β 1 ‐induced myofibroblast differentiation is currently largely unknown. Purpose To determine the contribution of GSK ‐3 signalling in TGF ‐β 1 ‐induced myofibroblast differentiation. Experimental Approach We used MRC 5 human lung fibroblasts and primary pulmonary fibroblasts of individuals with and without COPD . Protein and m RNA expression were determined by immunoblotting and RT‐PCR analysis respectively. Results Stimulation of MRC 5 and primary human lung fibroblasts with TGF ‐β 1 resulted in time‐ and dose‐dependent increases of α‐sm‐actin and fibronectin expression, indicative of myofibroblast differentiation. Pharmacological inhibition of GSK ‐3 by SB 216763 dose‐dependently attenuated TGF ‐β 1 ‐induced expression of these myofibroblasts markers. Moreover, silencing of GSK ‐3 by si RNA or pharmacological inhibition by CT/CHIR 99021 fully inhibited the TGF ‐β 1 ‐induced expression of α‐sm‐actin and fibronectin. The effect of GSK ‐3 inhibition on α‐sm‐actin expression was similar in fibroblasts from individuals with and without COPD . Neither smad, NF‐κB nor ERK 1/2 were involved in the inhibitory actions of GSK ‐3 inhibition by SB 126763 on myofibroblast differentiation. Rather, SB 216763 increased the phosphorylation of CREB , which in its phosphorylated form acts as a functional antagonist of TGF ‐β/smad signalling. Conclusion and Implication We demonstrate that GSK ‐3 signalling regulates TGF ‐β 1 ‐induced myofibroblast differentiation by regulating CREB phosphorylation. GSK ‐3 may constitute a useful target for treatment of chronic lung diseases.