title: Muscarinic receptor stimulation augments TGF-β1-induced contractile protein expression by airway smooth muscle cells.
abstract: Acetylcholine (ACh) is the primary parasympathetic neurotransmitter in the airways. Recently, it was established that ACh, via muscarinic receptors, regulates airway remodeling in animal models of asthma and chronic obstructive pulmonary disease (COPD). The mechanisms involved are not well understood. Here, we investigated the functional interaction between muscarinic receptor stimulation and transforming growth factor (TGF)-β(1) on the expression of contractile proteins in human airway smooth muscle (ASM) cells. ASM cells expressing functional muscarinic M(2) and M(3) receptors were stimulated with methacholine (MCh), TGF-β(1), or their combination for up to 7 days. Western blot analysis revealed a strong induction of sm-α-actin and calponin by TGF-β(1), which was increased by MCh in ASM cells. Immunocytochemistry confirmed these results and revealed that the presence of MCh augmented the formation of sm-α-actin stress fibers by TGF-β(1). MCh did not augment TGF-β(1)-induced gene transcription of contractile phenotype markers. Rather, translational processes were involved in the augmentation of TGF-β(1)-induced contractile protein expression by muscarinic receptor stimulation, including phosphorylation of glycogen synthase kinase-3β and 4E-binding protein 1, which was enhanced by MCh. In conclusion, muscarinic receptor stimulation augments functional effects of TGF-β(1) in human ASM cells on cellular processes that underpin ASM remodeling in asthma and COPD.
authors.affiliation: Department of Molecular Pharmacology, University of Groningen, The Netherlands. t.a.oenema@rug.nl
authors.forename: Tjitske A
authors.initials: TA
authors.lastname: Oenema
authors.forename: Marieke
authors.initials: M
authors.lastname: Smit
authors.forename: Lyanne
authors.initials: L
authors.lastname: Smedinga
authors.forename: Kurt
authors.initials: K
authors.lastname: Racké
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
authors.forename: Herman
authors.initials: H
authors.lastname: Meurs
authors.forename: Reinoud
authors.initials: R
authors.lastname: Gosens
mesh_terms: D000199:Actins / Q000096:biosynthesis; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000096:biosynthesis; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000096:biosynthesis*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D016210:Methacholine Chloride / Q000494:pharmacology; D008840:Microfilament Proteins / Q000096:biosynthesis; D018721:Muscarinic Agonists / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D014176:Protein Biosynthesis; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012137:Respiratory System / Q000187:drug effects* / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism* / Q000494:pharmacology; D000096985:Calponins
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D003285:Contractile Proteins; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D016210:Methacholine Chloride; D008840:Microfilament Proteins; D018721:Muscarinic Agonists; D010750:Phosphoproteins; D011976:Receptors, Muscarinic; D053773:Transforming Growth Factor beta1; D000096985:Calponins; C087000:EIF4EBP1 protein, human; C000605506:GSK3B protein, human