The carnitine/acylcarnitine translocase (CACT), an integral protein of the mitochondrial innermembrane, belongs to the carnitine-dependent system of fatty acid transport into mitochondria, where beta-oxidation occurs. CACT exchanges cytosolic acylcarnitine or free carnitine for carnitine in the mitochondrial matrix. The object of this study was to investigate in rat liver the effect, if any, of diets enriched with saturated fatty acids (beef tallow, BT, the control), n−3 polyunsaturated fatty acids (PUFA) (fish oil, FO), n−6 PUFA (safflower oil, SO), and mono-unsaturated fatty acids (MUFA) (olive oil,OO) on the activity and expression of CACT. Translocase exchange rates increased, in parallelwith CACTmRNA abundance, upon FO-feeding,whereas OO-dietary treatment induced a decrease in both CACT activity and expression. No changes were observed upon SO-feeding. Nuclear run-on assay revealed that FO-treatment increased the transcriptional rate of CACT mRNA. On the other hand, only in the nuclei of hepatocytes fromOO-fed rats splicing of the last intron of CACT pre-mRNA and the rate of formation of the 3′-endwere affected. Overall, these findings suggest that compared to the BT‐enriched diet, the SO-enriched diet did not influence CACT activity and expression, whereas FO- and OO-feeding alters CACT activity in an opposite fashion, i.e. modulating its expression at transcriptional and post-transcriptional levels, respectively.
Dietary fat types differently modulate the activity and expression of mitochondrialcarnitine/acylcarnitine translocase in rat liver
PRIORE, PAOLA;STANCA, ELEONORA;SICULELLA, Luisa
2012-01-01
Abstract
The carnitine/acylcarnitine translocase (CACT), an integral protein of the mitochondrial innermembrane, belongs to the carnitine-dependent system of fatty acid transport into mitochondria, where beta-oxidation occurs. CACT exchanges cytosolic acylcarnitine or free carnitine for carnitine in the mitochondrial matrix. The object of this study was to investigate in rat liver the effect, if any, of diets enriched with saturated fatty acids (beef tallow, BT, the control), n−3 polyunsaturated fatty acids (PUFA) (fish oil, FO), n−6 PUFA (safflower oil, SO), and mono-unsaturated fatty acids (MUFA) (olive oil,OO) on the activity and expression of CACT. Translocase exchange rates increased, in parallelwith CACTmRNA abundance, upon FO-feeding,whereas OO-dietary treatment induced a decrease in both CACT activity and expression. No changes were observed upon SO-feeding. Nuclear run-on assay revealed that FO-treatment increased the transcriptional rate of CACT mRNA. On the other hand, only in the nuclei of hepatocytes fromOO-fed rats splicing of the last intron of CACT pre-mRNA and the rate of formation of the 3′-endwere affected. Overall, these findings suggest that compared to the BT‐enriched diet, the SO-enriched diet did not influence CACT activity and expression, whereas FO- and OO-feeding alters CACT activity in an opposite fashion, i.e. modulating its expression at transcriptional and post-transcriptional levels, respectively.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
