Abstract
Hydrostatic pressure has a profound effect on cartilage tissue and chondrocyte metabolism. Depending on the type and magnitude of pressure various responses can occur in the cells. The mechanisms of mechanotransduction at cellular level and the events leading to specific changes in gene expression are still poorly understood. We have previously shown that induction of stress response in immortalized chondrocytes exposed to high static hydrostatic pressure increases the stability of heat shock protein 70 mRNA. In this study, our aim was to examine the effect of high pressure on gene expression profile and to study whether stabilization of mRNA molecules is a general phenomenon under this condition. For this purpose a cDNA array analysis was used to compare mRNA expression profile in pressurized vs. non‐pressurized human chondrosarcoma cells (HCS 2/8). mRNA stability was analyzed using actinomycin‐treated and nontreated samples collected after pressure treatment. A number of immediate‐early genes, and genes regulating cell cycle and growth were up‐regulated due to high pressure. Decrease in osteonectin, fibronectin, and collagen types VI and XVI mRNAs was observed. Also bikunin, cdc37 homologue and Tiam1, genes linked with hyaluronan metabolism, were down‐regulated. In general, stability of down‐regulated mRNA species appeared to increase. However, no increase in mRNA above control level due to stabilization was noticed in the genes available in the array. On the other hand, mRNAs of certain immediate‐early genes, like c‐jun, jun‐B and c‐myc, became destabilized under pressure treatment. Increased accumulation of mRNA on account of stabilization under high pressure conditions seems to be a tightly regulated, specific phenomenon.
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