This Article Full Text Full Text (PDF) All Versions of this Article: 2003-0240OCv1 31/1/54    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wang, L. Articles by Halayko, A. J. Search for Related Content PubMed PubMed Citation Articles by Wang, L. Articles by Halayko, A. J.

Mechanical Strain Inhibits Airway Smooth Muscle Gene Transcription via Protein Kinase C Signaling

Department of Physiology, and Asthma/COPD Research Centre, Department of Internal Medicine, Section of Respiratory Diseases, and Department of Oral Biology, University of Manitoba, Winnipeg; and Biology of Breathing Research Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada

Address correspondence to: Andrew J. Halayko, Section of Respiratory Diseases, University of Manitoba, Rm RS321 Respiratory Hospital, 810 Sherbrook Street, Winnipeg, MB, R3A 1R8 Canada. E-mail: ahalayk{at}cc.umanitoba.ca

Mechanical strain affects airway myocyte phenotype, cytoskeletal architecture, proliferation, and contractile function. We hypothesized that (i) short-term mechanical strain modulates transcription of smooth muscle–specific gene promoters for SM22 and smooth muscle myosin heavy chain (smMHC); and (ii) strain-induced change is mediated by altered actin polymerization in association with activation of protein kinase C (PKC). Primary cultured canine tracheal myocytes were transiently transfected with luciferase reporter plasmids harboring a murine SM22, human smMHC, or artificial serum response factor (SRF)-specific gene promoter and then subjected to cyclic strain for 48 h. This strain protocol significantly reduced transcriptional activity of SM22 and smMHC promoters and an artificial SRF-dependent promoter by 55 ± 5.9%, 57 ± 6.4%, and 75 ± 7.9%, respectively, with concomitant reduction in F/G actin ratio by 31 ± 8%. PKC inhibitors, GF109203X or Gö6976, significantly attenuated these affects. Similar to strain, strain-independent activation of PKC inhibited SM22, smMHC, and SRF-dependent promoter activity by 61 ± 4%, 66 ± 5%, and 28 ± 15%, respectively, and reduced the F/G actin ratio by 30 ± 5%. Gel shift assay revealed that PKC activation led to decreased binding of the required transcription factor, SRF, to CArG elements in the SM22 promoter. These data suggest a previously unknown role for PKC isoforms in mechanosensitive signaling in airway myocytes that is associated with coordinated regulation of actin cytoskeletal dynamics and smooth muscle–specific gene transcription.

Abbreviations: airway smooth muscle, ASM • Dulbecco's modified Eagle's medium, DMEM • deoxyribonuclease, Dnase • electrophoretic mobility shift assay, EMSA • filamentous actin, F-actin • fetal bovine serum, FBS • globular actin, G-actin • nonessential amino acids, NEAA • o-nitrophenyl-ß-D-galactoside, ONPG • phosphate-buffered saline, PBS • protein kinase C, PKC • phorbol-12-myristate-13-acetate, PMA • smooth muscle myosin heavy chain, smMHC • serum response factor, SRF • Tris Borate EDTA, TBE

This article has been cited by other articles:

				N. J. Fairbank, S. C. Connolly, J. D. MacKinnon, K. Wehry, L. Deng, and G. N. Maksym Airway smooth muscle cell tone amplifies contractile function in the presence of chronic cyclic strain Am J Physiol Lung Cell Mol Physiol, September 1, 2008; 295(3): L479 - L488. [Abstract] [Full Text] [PDF]

				A. J. Halayko, T. Tran, and R. Gosens Phenotype and Functional Plasticity of Airway Smooth Muscle: Role of Caveolae and Caveolins Proceedings of the ATS, January 1, 2008; 5(1): 80 - 88. [Abstract] [Full Text] [PDF]

				T. Tran, K. Ens-Blackie, E. S. Rector, G. L. Stelmack, K. D. McNeill, G. Tarone, W. T. Gerthoffer, H. Unruh, and A. J. Halayko Laminin-Binding Integrin {alpha}7 Is Required for Contractile Phenotype Expression by Human Airway Myocytes Am. J. Respir. Cell Mol. Biol., December 1, 2007; 37(6): 668 - 680. [Abstract] [Full Text] [PDF]

				S. S. An, T. R. Bai, J. H. T. Bates, J. L. Black, R. H. Brown, V. Brusasco, P. Chitano, L. Deng, M. Dowell, D. H. Eidelman, et al. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma Eur. Respir. J., May 1, 2007; 29(5): 834 - 860. [Abstract] [Full Text] [PDF]

				L. Wang, P. Chitano, and T. M. Murphy Length oscillation induces force potentiation in infant guinea pig airway smooth muscle Am J Physiol Lung Cell Mol Physiol, December 1, 2005; 289(6): L909 - L915. [Abstract] [Full Text] [PDF]

				M. L. Dowell, O. J. Lakser, W. T. Gerthoffer, J. J. Fredberg, G. L. Stelmack, A. J. Halayko, J. Solway, and R. W. Mitchell Latrunculin B increases force fluctuation-induced relengthening of ACh-contracted, isotonically shortened canine tracheal smooth muscle J Appl Physiol, February 1, 2005; 98(2): 489 - 497. [Abstract] [Full Text] [PDF]

				S. Albinsson, I. Nordstrom, and P. Hellstrand Stretch of the Vascular Wall Induces Smooth Muscle Differentiation by Promoting Actin Polymerization J. Biol. Chem., August 13, 2004; 279(33): 34849 - 34855. [Abstract] [Full Text] [PDF]