Mechanical stress and human aortic smooth muscle cell proliferation.

BACKGROUND

Mechanical forces related to pressure and flow are important for cell hypertrophy and proliferation.

OBJECTIVE

To test the hypothesis that mechanosensors are present that are sensitive solely to pure atmospheric pressure in the absence of shear and tensile stresses.

METHODS AND RESULTS

A pressure-loading apparatus was set up to examine the effects of atmospheric pressure on human aortic smooth muscle cells. Pressure application of 140 to 180 mmHg produced DNA synthesis in a pressure-dependent manner. In contrast, pressure of 120 mmHg or less produced no significant change. Pertussis toxin completely inhibited the pressure-induced increase of DNA synthesis under the high pressure of 200 mmHg. The activities of both extracellular signal-related kinase and c-Jun N-terminal kinase, but not of p38, were stimulated by a pressure of more than 160 mmHg.

CONCLUSION

These data suggest that human aortic smooth muscle cells have a mechanosensing cellular switch for DNA synthesis that is sensitive to pure atmospheric pressure, and that the molecular switch is activated by pressure of more than 140 mmHg. The activation mechanism consists of pertussis toxin-sensitive and -insensitive pathways, and the former is activated by high pure pressure.