Molecular mechanisms of low intensity pulsed ultrasound in human skin fibroblasts.
Soluble factors such as polypeptide growth factors, mitogenic lipids, inflammatory cytokines, and hormones are known regulators of cell proliferation. However, the effect of mechanical stimuli on cell proliferation is less well understood. Here we examined the effect of low intensity pulsed ultrasound (US), which is used to promote wound healing, on the proliferation of primary human foreskin fibroblasts and the underlying signaling mechanisms. We show that a single 6-11-min US stimulation increases bromodeoxyuridine incorporation. In addition, an increase in the total cell number is observed after sequential US stimulation. US induced stress fiber and focal adhesion formation via activation of Rho. We further observed that US selectively induced activation of extracellular signal-regulated kinase (ERK) 1/2. Inhibition of Rho-associated coiled-coil-containing protein kinase (ROCK) prevented US-induced ERK1/2 activation, demonstrating that the Rho/ROCK pathway is an upstream regulator of ERK activation in response to US. Consequently, activation of ROCK and MEK-1 was required for US-induced DNA synthesis. Finally, an integrin beta(1) blocking antibody as well as a RGD peptide prevented US-induced DNA synthesis. In addition, US slightly increased phosphorylation of Src at Tyr(416), and Src activity was found to be required for ERK1/2 activation in response to US. In conclusion, our data demonstrate for the first time that US promotes cell proliferation via activation of integrin receptors and a Rho/ROCK/Src/ERK signaling pathway.
Department of Clinical Chemistry, University of Ulm, D-89081 Ulm, Germany.
Shaoxia
S
Zhou
Andreas
A
Schmelz
Thomas
T
Seufferlein
Yiping
Y
Li
Jinshun
J
Zhao
Max G
MG
Bachem
D000906:Antibodies / Q000494:pharmacology; D002452:Cell Count; D002455:Cell Division; D004247:DNA / Q000096:biosynthesis; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000276:immunology / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D010766:Phosphorylation; D010812:Physical Stimulation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D012867:Skin / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D014464:Ultrasonic Therapy; D014465:Ultrasonics; D054460:rho-Associated Kinases; D019061:src-Family Kinases / Q000378:metabolism
D000906:Antibodies; D004791:Enzyme Inhibitors; D019012:Integrin beta1; D047908:Intracellular Signaling Peptides and Proteins; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid; D004247:DNA; D019061:src-Family Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1