Sulfur-substituted and alpha-methylated fatty acids as peroxisome proliferator-activated receptor activators.
FA with varying chain lengths and an alpha-methyl group and/or a sulfur in the beta-position were tested as peroxisome proliferator-activated receptor (PPAR)alpha, -delta(beta), and -gamma ligands by transient transfection in COS-1 cells using chimeric receptor expression plasmids, containing cDNAs encoding the ligand-binding domain of PPARalpha, -delta, and -gamma. For PPARalpha, an increasing activation was found with increasing chain length of the sulfur-substituted FA up to C14-S acetic acid (tetradecylthioacetic acid = TTA). The derivatives were poor, and nonsignificant, activators of PPARdelta. For PPARgamma, activation increased with increasing chain length up to C16-S acetic acid. A methyl group was introduced in the alpha-position of palmitic acid, TTA, EPA, DHA, cis9,trans11 CLA, and trans10,cis12 CLA. An increased activation of PPARalpha was obtained for the alpha-methyl derivatives compared with the unmethylated FA. This increase also resulted in increased expression of the two PPARalpha target genes acyl-CoA oxidase and liver FA-binding protein for alpha-methyl TTA, alpha-methyl EPA, and alpha-methyl DHA. Decreased or altered metabolism of these derivatives in the cells cannot be excluded. In conclusion, saturated FA with sulfur in the beta-position and increasing carbon chain length from C9-S acetic acid to C14-S acetic acid have increasing effects as activators of PPARalpha and -gamma in transfection assays. Furthermore, alpha-methyl FA derivatives of a saturated natural FA (palmitic acid), a sulfur-substituted FA (TTA), and PUFA (EPA, DHA, c9,t11 CLA, and t10,c12 CLA) are stronger PPARalpha activators than the unmethylated compounds.
Larsen
Laila N
LN
Institute of Basic Medical Sciences, Department of Biochemistry, University of Oslo, Norway. l.n.larsen@medisin.uio.no
Granlund
Linda
L
Holmeide
Anne Kristin
AK
Skattebøl
Lars
L
Nebb
Hilde Irene
HI
Bremer
Jon
J
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D005227:Fatty Acids / Q000737:chemistry / Q000494:pharmacology*; D008024:Ligands; D008745:Methylation; D047493:PPAR alpha / Q000819:agonists; D047494:PPAR delta / Q000819:agonists; D047495:PPAR gamma / Q000819:agonists; D047492:Peroxisome Proliferator-Activated Receptors / Q000819:agonists*; D013329:Structure-Activity Relationship; D013457:Sulfur Compounds; D014162:Transfection
D005227:Fatty Acids; D008024:Ligands; D047493:PPAR alpha; D047494:PPAR delta; D047495:PPAR gamma; D047492:Peroxisome Proliferator-Activated Receptors; D013457:Sulfur Compounds