Metabolic pathway that produces essential fatty acids from polymethylene-interrupted polyunsaturated fatty acids in animal cells.
Sciadonic acid (20:3 Delta-5,11,14) and juniperonic acid (20:4 Delta-5,11,14,17) are polyunsaturated fatty acids (PUFAs) that lack the Delta-8 double bond of arachidonic acid (20:4 Delta-5,8,11,14) and eicosapentaenoic acid (20:5 Delta-5,8,11,14,17), respectively. Here, we demonstrate that these conifer oil-derived PUFAs are metabolized to essential fatty acids in animal cells. When Swiss 3T3 cells were cultured with sciadonic acid, linoleic acid (18:2 Delta-9,12) accumulated in the cells to an extent dependent on the concentration of sciadonic acid. At the same time, a small amount of 16:2 Delta-7,10 appeared in the cellular lipids. Both 16:2 Delta-7,10 and linoleic acid accumulated in sciadonic acid-supplemented CHO cells, but not in peroxisome-deficient CHO cells. We confirmed that 16:2 Delta-7,10 was effectively elongated to linoleic acid in rat liver microsomes. These results indicate that sciadonic acid was partially degraded to 16:2 Delta-7,10 by two cycles of beta-oxidation in peroxisomes, then elongated to linoleic acid in microsomes. Supplementation of Swiss 3T3 cells with juniperonic acid, an n-3 analogue of sciadonic acid, induced accumulation of alpha-linolenic acid (18:3 Delta-9,12,15) in cellular lipids, suggesting that juniperonic acid was metabolized in a similar manner to sciadonic acid. This PUFA remodeling is thought to be a process that converts unsuitable fatty acids into essential fatty acids required by animals.
Tanaka
Tamotsu
T
Department of Applied Biological Science, Fukuyama University, Higashimura, Fukuyama, Hiroshima 729-0292, Japan. tamot@fubac.fukuyama-u.ac.jp
Morishige
Jun-ichi
J
Iwawaki
Dai
D
Fukuhara
Terumi
T
Hamamura
Naomi
N
Hirano
Kaoru
K
Osumi
Takashi
T
Satouchi
Kiyoshi
K
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D005228:Fatty Acids, Essential / Q000096:biosynthesis*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D019787:Linoleic Acid / Q000096:biosynthesis; D053858:Metabolic Networks and Pathways; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism; D020675:Peroxisomes / Q000378:metabolism; D051381:Rats; D041701:Swiss 3T3 Cells; D017962:alpha-Linolenic Acid / Q000096:biosynthesis
D001095:Arachidonic Acids; D005228:Fatty Acids, Essential; D005231:Fatty Acids, Unsaturated; C437903:juniperonic acid; D017962:alpha-Linolenic Acid; C045533:eicosa-5,11,14-trienoic acid; D019787:Linoleic Acid