Shear stress activates Akt during vascular smooth muscle cell reorientation.
Vascular intervention procedures can lead to endothelial damage and expose the underlying VSMCs (vascular smooth muscle cells) to shear stress. Although shear stress has been implicated in the proliferation and migration of VSMCs, the molecular mechanism(s) underlying these events are not well understood. In the present study, we examined the effect of shear stress on VSMC reorientation and the activation of Akt (also called protein kinase B) pathway signalling. Cells were subjected to a shear of 9.8 dynes/cm2 (1 dyne=10-5 N) for 0 min, 5 min, 15 min, 30 min, 1 h, 4 h and 24 h. Shear stress caused the VSMCs to realign at an angle that was approximately 45 degrees relative to the shear force vector after 24 h. Immunoblotting demonstrated that the phosphorylations of Akt and Akt-related signalling proteins [mTOR (mammalian target of rapamycin), PTEN (phosphatase and tensin homologue deleted on chromosome 10) and p70S6k (p70 S6-kinase)] were increased after shear stimulation. These results indicate that the activation of the Akt pathway signalling is closely correlated with shear-induced VSMC reorientation.
Rice
Kevin M
KM
Department of Biological Sciences, Marshall University, Huntington, WV 45755, U.S.A.
Kakarla
Sunil K
SK
Mupparaju
Sriram P
SP
Paturi
Satyanarayana
S
Katta
Anjaiah
A
Wu
Miaozong
M
Harris
Robert T
RT
Blough
Eric R
ER
D002465:Cell Movement; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D058570:TOR Serine-Threonine Kinases
D047908:Intracellular Signaling Peptides and Proteins; C546842:MTOR protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human