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Effect of dietary lipids on phospholipase D activity in rat brain
1Department of Pediatrics, The University of Mississippi Medical Center, Jackson 39216, USA. jpeng@ped.umsmed.edu
Insights
Dietary lipids significantly impact brain Phospholipase D (PLD) activity. Safflower and fish oils reduced specific PLD activities, while safflower oil increased others, indicating lipid modulation of phospholipid metabolism.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Phospholipase D (PLD) is increasingly recognized for its role in cellular signaling pathways.
- Emerging research links cell membrane composition to enzyme functionality, suggesting dietary influences on brain PLD activity.
Purpose of the Study:
- To investigate the impact of dietary lipid intake, specifically safflower and fish oils, on brain Phospholipase D (PLD) activity in developing rats.
- To determine how different lipid compositions affect specific PLD isozymes within brain microsomes and synaptosomes.
Main Methods:
- Rat dams were fed diets supplemented with safflower oil, fish oil, or a control chow.
- Pups were weaned onto these diets and sacrificed at 30 days of age.
- Phospholipase D (PLD) activity was quantified using transphosphatidylation assays on isolated brain microsomes and synaptosome (P2) membranes, measuring both GTPγS-dependent and oleate-dependent activities.
Main Results:
- Microsomal GTPγS-dependent PLD activity was reduced by 38% in the safflower oil group and 30% in the fish oil group compared to controls.
- Oleate-dependent PLD activity in microsomes increased by 38% in the safflower oil group.
- Synaptosome (P2) GTPγS-dependent PLD activity increased by 29% in the safflower oil group, with no significant changes in oleate-dependent activity or in the fish oil group for this fraction.
Conclusions:
- Dietary lipid composition significantly modulates phospholipid metabolism in the developing rat brain.
- Specific PLD isozymes exhibit differential responses to dietary fatty acid intake, suggesting targeted roles in brain function.
- These findings highlight the critical role of early-life nutrition in brain lipid signaling pathways.
Abstract:
Phospholipase D (PLD) is emerging as a major player in many novel signaling pathways. Based on recent studies correlating membrane composition with enzyme function, we speculated that feeding of dietary lipids to the newborns has a major impact on brain PLD activity. To test this hypothesis, the rat dams were fed fat-free powder containing either safflower oil or fish oil, and a control powdered chow. The pups were weaned onto the diet and sacrificed at 30 days of age. PLD activity was measured by transphosphatidylation assays using rat brain membranes. This study shows that microsome GTPgammaS-dependent PLD activity in rats fed safflower oil or fish oil was significantly reduced by 38% and 30% respectively compared to controls. Oleate-dependent PLD activity in the safflower oil group, however, was significantly increased by 38%. In contrast, synaptosome membrane (P2) GTPgammaS-dependent PLD activity in rats consuming safflower oil was significantly increased by 29%, but there was no difference in oleate-dependent PLD activity. Likewise, no difference was observed in microsome oleate-dependent PLD and P2 GTPgammaS-dependent PLD activity between the fish oil and the control groups. These results indicate that dietary lipid intake appears to modulate phospholipid metabolism and differential expression of PLD isozymes in the brain.