EXTRACELLULAR-MATRIX COMPONENTS AFFECT THE PATTERN OF PROTEIN-SYNTHESIS OF ENDOTHELIAL-CELLS RESPONDING TO HYPERTHERMIA

The biosynthetic profile of endothelial cells responding to hypertherm ia is altered by extracellular matrix components. The extracellular ma trix components influence the quantitative expression of members of th e HSP70 family and HSP90. The expression of several HSP70 mRNA species , which are strictly stress inducible, are modulated by extracellular matrix components. Both laminin and collagen type IV decrease the amou nt of HSP70 protein and mRNA expressed by endothelial cells exposed to hyperthermia relative to control cultures attached to virgin plastic. In contrast, both laminin and collagen type TV increased the amount o f HSP90 mRNA constitutively expressed by endothelial cells at 37 degre es C. When endothelial cells were exposed to elevated temperatures, th ese two extracellular matrix proteins decrease the amount of HSP90 mRN A relative to control cultures attached to virgin plastic. Our observa tions are consistent with the proposal that the extracellular matrix c omponents regulate gene expression and cell behavior in regard to ther motolerance.