CPT1alpha over-expression increases long-chain fatty acid oxidation and reduces cell viability with incremental palmitic acid concentration in 293T cells.
To test the cellular response to an increased fatty acid oxidation, we generated a vector for an inducible expression of the rate-limiting enzyme carnitine palmitoyl-transferase 1alpha (CPT1alpha). Human embryonic 293T kidney cells were transiently transfected and expression of the CPT1alpha transgene in the tet-on vector was activated with doxycycline. Fatty acid oxidation was measured by determining the conversion of supplemented, synthetic cis-10-heptadecenoic acid (C17:1n-7) to C15:ln-7. CPT1alpha over-expression increased mitochondrial long-chain fatty acid oxidation about 6-fold. Addition of palmitic acid (PA) decreased viability of CPT1alpha over-expressing cells in a concentration-dependent manner. Both, PA and CPT1alpha over-expression increased cell death. Interestingly, PA reduced total cell number only in cells over-expressing CPT1alpha, suggesting an effect on cell proliferation that requires PA translocation across the mitochondrial inner membrane. This inducible expression system should be well suited to study the roles of CPT1 and fatty acid oxidation in lipotoxicity and metabolism in vivo.
Jambor de Sousa
Ulrike L
UL
Institute of Animal Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland.
Koss
Michael D
MD
Fillies
Marion
M
Gahl
Anja
A
Scheeder
Martin R L
MR
Cardoso
M Cristina
MC
Leonhardt
Heinrich
H
Geary
Nori
N
Langhans
Wolfgang
W
Leonhardt
Monika
M
D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000166:cytology* / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000502:physiology; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
D005227:Fatty Acids; D011994:Recombinant Proteins; D019308:Palmitic Acid; D002334:Carnitine O-Palmitoyltransferase