The effects of hydrostatic pressure-induced changes on the cytoskeleton and on the regulation of gene expression in pheochromocytoma (PC-12) cells.

The purpose of this investigation was to determine the relationship of hydrostatic pressure-induced changes in the cytoarchitecture to regulation of gene expression in PC-12 cells. Hydrostatic pressure disrupts the cytoskeleton, decreases tubulin and actin mRNA levels and causes changes in the localization of tubulin and actin mRNA. Actin mRNA levels, at 6000 and 10,000 psi for 20 min, were reduced to 78% and 64%, respectively, in undifferentiated cells and to 81% and 72%, respectively, in 4-day differentiating cells, relative to untreated controls. Tubulin mRNA levels, at 6000 and 10,000 psi for 20 min, were reduced to 75% and 67%, respectively, in undifferentiated cells and to 84% and 74%, respectively, in 4-day differentiating cells. Changes in the localization of mRNA in the soluble and cytoskeletal fractions were determined by measuring the pressure level where the mRNA level in the cytoskeletal fraction equals the mRNA level in the soluble fraction. This measurement was designated the cytoskeletal/soluble fraction index (CSFI(50)). CSFI(50)measurements indicated that following hydrostatic pressure, actin mRNA cytoskeletal association was more stable than tubulin mRNA cytoskeletal association. The addition of chemicals which stabilize or destabilize microtubules and microfilaments to pressure treatment resulted in additional changes in the CSFI(50).