Published ahead of print on February 19, 2004, doi:10.1165/rcmb.2003-0240OC Am. J. Respir. Cell Mol. Biol., Volume 31, Number 1, July 2004, 54-61 A more recent version of this article appeared on July 1, 2004
Submitted on June 24, 2003 Mechanical strain inhibits airway smooth muscle gene transcription via protein kinase C signalingLU WANG1,1 DEPARTMENT OF PHYSIOLOGY, UNIVERSITY OF MANITOBA, WINNIPEG, MB, Canada, 2 ASTHMA/COPD RESEARCH CENTRE AND DEPARTMENT OF INTERNAL MEDICINE, SECTION OF RESPIRATORY DISEASES, UNIVERSITY OF MANITOBA, WINNIPEG, MB, Canada, 3 DEPARTMENT OF ORAL BIOLOGY, UNIVERSITY OF MANITOBA, WINNIPEG, MB, Canada; BIOLOGY OF BREATHING RESEARCH GROUP, MANITOBA INSTITUTE OF CHILD HEALTH, WINNIPEG, MB, Canada, 4 DEPARTMENT OF PHYSIOLOGY, UNIVERSITY OF MANITOBA, WINNIPEG, MB, Canada; ASTHMA/COPD RESEARCH CENTRE AND DEPARTMENT OF INTERNAL MEDICINE, SECTION OF RESPIRATORY DISEASES, UNIVERSITY OF MANITOBA, WINNIPEG, MB, Canada; BIOLOGY OF BREATHING RESEARCH GROUP, MANITOBA INSTITUTE OF CHILD HEALTH, WINNIPEG, MB, Canada * To whom correspondence should be addressed. E-mail: ahalayk{at}cc.umanitoba.ca.
Mechanical strain affects airway myocyte phenotype, cytoskeletal architecture, proliferation, and contractile function. We hypothesized that 1) short term mechanical strain modulates transcription of smooth muscle-specific gene promoters for SM22 and smooth muscle myosin heavy chain (smMHC); and 2) 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 Go6976, 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.
This article has been cited by other articles:
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
