This Article Full Text Full Text (PDF) All Versions of this Article: 2003-0272OCv1 31/3/266    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 Halayko, A. J. Articles by Solway, J. Search for Related Content PubMed PubMed Citation Articles by Halayko, A. J. Articles by Solway, J.

Phophatidylinositol-3 Kinase/Mammalian Target of Rapamycin/p70^S6K Regulates Contractile Protein Accumulation in Airway Myocyte Differentiation

Departments of Medicine and Pediatrics, University of Chicago, Chicago, Illinois; Department of Physiology, and Section of Respiratory Diseases (Asthma/COPD Research Centre), University of Manitoba, and Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada; and Departments of Pediatrics and Communicable Diseases, Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan

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

Increased airway smooth muscle in airway remodeling results from myocyte proliferation and hypertrophy. Skeletal and vascular smooth muscle hypertrophy is induced by phosphatidylinositide-3 kinase (PI(3) kinase) via mammalian target of rapamycin (mTOR) and p70S6 kinase (p70^S6K). We tested the hypothesis that this pathway regulates contractile protein accumulation in cultured canine airway myocytes acquiring an elongated contractile phenotype in serum-free culture. In vitro assays revealed a sustained activation of PI(3) kinase and p70^S6K during serum deprivation up to 12 d, with concomitant accumulation of SM22 and smooth muscle myosin heavy chain (smMHC) proteins. Immunocytochemistry revealed that activation of PI3K/mTOR/p70^S6K occurred almost exclusively in myocytes that acquire the contractile phenotype. Inhibition of PI(3) kinase or mTOR with LY294002 or rapamycin blocked p70^S6K activation, prevented formation of large elongated contractile phenotype myocytes, and blocked accumulation of SM22 and smMHC. Inhibition of MEK had no effect. Steady-state mRNA abundance for SM22 and smMHC was unaffected by blocking p70^S6K activation. These studies provide primary evidence that PI(3) kinase and mTOR activate p70^S6K in airway myocytes leading to the accumulation of contractile apparatus proteins, differentiation, and growth of large, elongated contractile phenotype airway smooth muscle cells.

Abbreviations: Dulbecco's modified Eagle's medium, DMEM • glycogen synthase kinase-3ß, GSK-3ß • insulin-like growth factor-1, IGF-1 • mammalian target of rapamycin, mTOR • 3-phosphoinositide–dependent protein kinase, PDK1 • phosphatidylinositol-3 kinase, PI(3) kinase • smooth muscle myosin heavy chain, smMHC

This article has been cited by other articles:

				Y. Wu, Y. Huang, B. P. Herring, and S. J. Gunst Integrin-linked kinase regulates smooth muscle differentiation marker gene expression in airway tissue Am J Physiol Lung Cell Mol Physiol, December 1, 2008; 295(6): L988 - L997. [Abstract] [Full Text] [PDF]

				Y. Q. Xiao, C. G. Freire-de-Lima, W. P. Schiemann, D. L. Bratton, R. W. Vandivier, and P. M. Henson Transcriptional and Translational Regulation of TGF-{beta} Production in Response to Apoptotic Cells J. Immunol., September 1, 2008; 181(5): 3575 - 3585. [Abstract] [Full Text] [PDF]

				R. O. Nunes, M. Schmidt, G. Dueck, H. Baarsma, A. J. Halayko, H. A. M. Kerstjens, H. Meurs, and R. Gosens GSK-3/{beta}-catenin signaling axis in airway smooth muscle: role in mitogenic signaling Am J Physiol Lung Cell Mol Physiol, June 1, 2008; 294(6): L1110 - L1118. [Abstract] [Full Text] [PDF]

				H. Deng, G. A. Dokshin, J. Lei, A. M. Goldsmith, K. N. Bitar, D. C. Fingar, M. B. Hershenson, and J. K. Bentley Inhibition of Glycogen Synthase Kinase-3{beta} Is Sufficient for Airway Smooth Muscle Hypertrophy J. Biol. Chem., April 11, 2008; 283(15): 10198 - 10207. [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]

				J. K. Bentley and M. B. Hershenson Airway Smooth Muscle Growth in Asthma: Proliferation, Hypertrophy, and Migration Proceedings of the ATS, January 1, 2008; 5(1): 89 - 96. [Abstract] [Full Text] [PDF]

				P. Sharma, T. Tran, G. L. Stelmack, K. McNeill, R. Gosens, M. M. Mutawe, H. Unruh, W. T. Gerthoffer, and A. J. Halayko Expression of the dystrophin-glycoprotein complex is a marker for human airway smooth muscle phenotype maturation Am J Physiol Lung Cell Mol Physiol, January 1, 2008; 294(1): L57 - L68. [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. Albinsson and P. Hellstrand Integration of signal pathways for stretch-dependent growth and differentiation in vascular smooth muscle Am J Physiol Cell Physiol, August 1, 2007; 293(2): C772 - C782. [Abstract] [Full Text] [PDF]

				D. Schaafsma, K. D. McNeill, G. L. Stelmack, R. Gosens, H. A. Baarsma, B. G. J. Dekkers, E. Frohwerk, J.-M. Penninks, P. Sharma, K. M. Ens, et al. Insulin increases the expression of contractile phenotypic markers in airway smooth muscle Am J Physiol Cell Physiol, July 1, 2007; 293(1): C429 - C439. [Abstract] [Full Text] [PDF]

				R. Gosens, G. Dueck, W. T. Gerthoffer, H. Unruh, J. Zaagsma, H. Meurs, and A. J. Halayko p42/p44 MAP kinase activation is localized to caveolae-free membrane domains in airway smooth muscle Am J Physiol Lung Cell Mol Physiol, May 1, 2007; 292(5): L1163 - L1172. [Abstract] [Full Text] [PDF]

				D. Clements, R. J. Mayer, and S. R. Johnson Subcellular distribution of the TSC2 gene product tuberin in human airway smooth muscle cells is driven by multiple localization sequences and is cell-cycle dependent Am J Physiol Lung Cell Mol Physiol, January 1, 2007; 292(1): L258 - L266. [Abstract] [Full Text] [PDF]

				R. Gosens, G. L. Stelmack, G. Dueck, K. D. McNeill, A. Yamasaki, W. T. Gerthoffer, H. Unruh, A. S. Gounni, J. Zaagsma, and A. J Halayko Role of caveolin-1 in p42/p44 MAP kinase activation and proliferation of human airway smooth muscle Am J Physiol Lung Cell Mol Physiol, September 1, 2006; 291(3): L523 - L534. [Abstract] [Full Text] [PDF]

				B. Camoretti-Mercado, D. J. Fernandes, S. Dewundara, J. Churchill, L. Ma, P. C. Kogut, J. F. McConville, M. S. Parmacek, and J. Solway Inhibition of Transforming Growth Factor beta-enhanced Serum Response Factor-dependent Transcription by SMAD7 J. Biol. Chem., July 21, 2006; 281(29): 20383 - 20392. [Abstract] [Full Text] [PDF]

				A. M. Goldsmith, J. K. Bentley, L. Zhou, Y. Jia, K. N. Bitar, D. C. Fingar, and M. B. Hershenson Transforming Growth Factor-beta Induces Airway Smooth Muscle Hypertrophy Am. J. Respir. Cell Mol. Biol., February 1, 2006; 34(2): 247 - 254. [Abstract] [Full Text] [PDF]

				C. Boxall, S. T. Holgate, and D. E. Davies The contribution of transforming growth factor-{beta} and epidermal growth factor signalling to airway remodelling in chronic asthma Eur. Respir. J., January 1, 2006; 27(1): 208 - 229. [Abstract] [Full Text] [PDF]

				L. Zhou, A. M. Goldsmith, J. K. Bentley, Y. Jia, M. L. Rodriguez, M. K. Abe, D. C. Fingar, and M. B. Hershenson 4E-Binding Protein Phosphorylation and Eukaryotic Initiation Factor-4E Release Are Required for Airway Smooth Muscle Hypertrophy Am. J. Respir. Cell Mol. Biol., August 1, 2005; 33(2): 195 - 202. [Abstract] [Full Text] [PDF]

				C. Lecureuil, S. Tesseraud, E. Kara, N. Martinat, A. Sow, I. Fontaine, C. Gauthier, E. Reiter, F. Guillou, and P. Crepieux Follicle-Stimulating Hormone Activates p70 Ribosomal Protein S6 Kinase by Protein Kinase A-Mediated Dephosphorylation of Thr 421/Ser 424 in Primary Sertoli Cells Mol. Endocrinol., July 1, 2005; 19(7): 1812 - 1820. [Abstract] [Full Text] [PDF]