CHANGES IN mRNA LEVELS OF INTRACELLULAR FATTY ACID METABOLISM REGULATORS IN HUMAN HEPATOMA HepG2 CELLS FOLLOWING THEIR TREATMENT WITH NON-ESTERIFIED FATTY ACIDS AND DEHYDROEPIANDROSTERONE

The effects of non-esterified fatty acids (NEFA) and hormone dehydroepiandrosterone (DHEA) on the levels of mRNAs of protein kinase C (PKC) -δ and -e isoforms and those of liver fatty acid binding protein (L-FABP) were investigated in the human hepatoma HepG2 cell line. The cells were kept in low-serum, low-albumin medium during experiments. Low FA levels (100 µM) and time intervals of 4 h and 20 h were used. In these conditions, the saturated (palmitic, stearic) and monounsaturated (oleic) acids rather selectively stimulated PKC-e mRNA levels. Unexpectedly, we found that these acids also suppressed liver fatty-acid binding protein (L-FABP) mRNA levels. DHEA in pharmacological doses (100 µM) produced a significant increase in PKC-δ and -e mRNA levels. Although molecular mechanisms underlying the identified changes have not been investigated in this paper, our findings emphasize that NEFA-induced modulation of mRNA levels of key signalling components represent an additional mechanism for how the ambient NEFA can influence metabolic homeostasis in cells.