Plasmalogen metabolism-related enzymes in rat brain during aging: influence of n-3 fatty acid intake.
Plasmalogens (Pls) are phospholipids containing a vinyl-ether bond at the sn-1 position of the glycerol backbone. They represent between 1/2 and 2/3 of the ethanolamine phospholipids in the brain. During aging, the Pls content in human brain falls down. However, the role of Pls metabolism-related enzymes in the regulation of Pls levels remains to be determined. Dihydroxyacetone phosphate acyltransferase (DHAP-AT) is the enzyme involved in the first step of Pls biosynthesis. In the brain, a phospholipase A2, which selectively acts on Pls, has been isolated (Pls-PLA2s). In this work, we aimed to evaluate the impact of DHAP-AT (a key enzyme of Pls biosynthesis) and Pls-PLA2 (a specific Pls degradation enzyme) on the evolution of Pls content in the rat brain during aging. The influence of n-3 fatty acid intake was also evaluated. Littermates from two generations of n-3 deficient rats were fed an equilibrated diet containing either alpha-LNA alone or with two doses of DHA. After weaning, 3, 9 or 21 months of diet, rats were sacrificed. Enzymatic assays were performed, Pls levels were assessed and the sn-2 position of ethanolamine Pls was analyzed. DHAP-AT activity significantly increased between weaning and 3 months with a concomitant increase of brain Pls, which reached maximal levels after 9 months. Then, Pls levels and DHAP-AT activity significantly decreased while Pls-PLA2s activity significantly increased. Dietary n-3 fatty acids had no effect on DHAP-AT activity and on Pls levels. In conclusion, the increase of brain Pls content in the first part of the life may be related to the high increase of DHAP-AT activity, probably stimulated by DHA. In aged animals, the decrease of Pls levels may mainly be caused to an increase of their degradation by Pls-PLA2. Dietary DHA may not oppose the physiologic aging.
André
A
A
UMR Inra-ENESAD Flaveur, vision et Comportement du consommateur, 17, rue Sully, BP 86510, 21065 Dijon cedex, France.
Juanéda
P
P
Sébédio
J L
JL
Chardigny
J M
JM
D000217:Acyltransferases / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D008297:Male; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010955:Plasmalogens / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D004042:Dietary Fats, Unsaturated; D010955:Plasmalogens; D004281:Docosahexaenoic Acids; D000217:Acyltransferases; C020051:glycerone-phosphate O-acyltransferase; D010741:Phospholipases A; D054467:Phospholipases A2; C117522:plasmalogen-selective phospholipase A2