Plasmalogen metabolism-related enzymes in rat brain during aging: influence of n-3 fatty acid intake

• Published in: Biochimie 2006, Vol.88 (1), p.103-111
• Main Authors: André, A., Juanéda, P., Sébédio, J.L., Chardigny, J.M.
• Format: Article
• Language: English
• Subjects: Acyltransferases - metabolism; Aging; Aging - physiology; Animals; Biochemistry, Molecular Biology; Brain; Brain - enzymology; Dietary Fats, Unsaturated - pharmacology; Dihydroxyacetone phosphate acyltransferase; Docosahexaenoic Acids - pharmacology; Life Sciences; Male; Phospholipase A 2; Phospholipases A - metabolism; Phospholipases A2; Plasmalogen; Plasmalogens - metabolism; Rats; Rats, Wistar
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2005.06.010

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 A 2, which selectively acts on Pls, has been isolated (Pls-PLA 2s). In this work, we aimed to evaluate the impact of DHAP-AT (a key enzyme of Pls biosynthesis) and Pls-PLA 2 (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 α-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-PLA 2s 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-PLA 2. Dietary DHA may not oppose the physiologic aging.