Novel effect of C75 on carnitine palmitoyltransferase I activity and palmitate oxidation.
C75 is a potential drug for the treatment of obesity. It was first identified as a competitive, irreversible inhibitor of fatty acid synthase (FAS). It has also been described as a malonyl-CoA analogue that antagonizes the allosteric inhibitory effect of malonyl-CoA on carnitine palmitoyltransferase I (CPT I), the main regulatory enzyme involved in fatty acid oxidation. On the basis of MALDI-TOF analysis, we now provide evidence that C75 can be transformed to its C75-CoA derivative. Unlike the activation produced by C75, the CoA derivative is a potent competitive inhibitor that binds tightly but reversibly to CPT I. IC50 values for yeast-overexpressed L- or M-CPT I isoforms, as well as for purified mitochondria from rat liver and muscle, were within the same range as those observed for etomoxiryl-CoA, a potent inhibitor of CPT I. When a pancreatic INS(823/13), muscle L6E9, or kidney HEK293 cell line was incubated directly with C75, fatty acid oxidation was inhibited. This suggests that C75 could be transformed in the cell to its C75-CoA derivative, inhibiting CPT I activity and consequently fatty acid oxidation. In vivo, a single intraperitoneal injection of C75 in mice produced short-term inhibition of CPT I activity in mitochondria from the liver, soleus, and pancreas, indicating that C75 could be transformed to its C75-CoA derivative in these tissues. Finally, in silico molecular docking studies showed that C75-CoA occupies the same pocket in CPT I as palmitoyl-CoA, suggesting an inhibiting mechanism based on mutual exclusion. Overall, our results describe a novel role for C75 in CPT I activity, highlighting the inhibitory effect of its C75-CoA derivative.
Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain.
Assia
A
Bentebibel
David
D
Sebastián
Laura
L
Herrero
Eduardo
E
López-Viñas
Dolors
D
Serra
Guillermina
G
Asins
Paulino
P
Gómez-Puertas
Fausto G
FG
Hegardt
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000214:Acyl Coenzyme A / Q000096:biosynthesis / Q000494:pharmacology; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002478:Cells, Cultured; D003066:Coenzyme A Ligases / Q000378:metabolism; D004852:Epoxy Compounds / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008930:Mitochondria, Liver / Q000201:enzymology; D008931:Mitochondria, Muscle / Q000201:enzymology; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
C406734:4-methylene-2-octyl-5-oxofuran-3-carboxylic acid; D000214:Acyl Coenzyme A; C510483:C75-coenzyme A; D004852:Epoxy Compounds; D019308:Palmitic Acid; D002334:Carnitine O-Palmitoyltransferase; D003066:Coenzyme A Ligases; C054207:etomoxir; D015107:4-Butyrolactone