title: Dietary polyunsaturated fat that is low in (n-3) and high in (n-6) fatty acids alters the SNARE protein complex and nitrosylation in rat hippocampus.
abstract: Docosahexaenoic acid [DHA, 22:6(n-3)] is enriched in brain membrane phospholipids and is important to brain development and function through its influence on neurite outgrowth and neurotransmitter secretion. Fusion of intracellular vesicles with the plasma membrane involving SNARE [soluble N-ethylmaleimide-sensitive fusion (NSF) protein attachment protein receptor] protein assembly, membrane fusion, and then disassembly are events common in membrane extension and neurotransmitter release. We determined whether feeding an (n-3) fatty acid-deficient diet, known to reduce brain phospholipid DHA, alters SNARE protein and SNARE complex expression or protein nitrosylation in the hippocampus of rats. Female rats were fed diets with 1.3 or 0.02% energy (n-3) alpha-linolenic acid from 2 wk before gestation then throughout gestation and lactation (n = 8/diet), and the male offspring were weaned to the maternal diet. Hippocampus phospholipid fatty acids and SNARE proteins were determined in male offspring at 90 d of age. Hippocampus phospholipid DHA was lower and (n-6) docosapentaenoic acid [DPA, 22:5(n-6)] was higher in the (n-3) fatty acid-deficient rats compared with the control group (P < 0.05). Multiplex Western blots using antibodies to syntaxin, synaptosome-associated protein of 25kDa (SNAP-25), and complexin II, showed higher ternary SNARE complexes but no differences in syntaxin, SNAP-25, or complex II expression in hippocampus of the (n-3) fatty acid-deficient rats compared with the control group (P < 0.05). S-nitrosylation of syntaxin was also significantly lower in the (n-3) fatty acid-deficient rats than in the control group. These studies suggest that altered SNARE complex binding or disassembly could be important in explaining the diverse cellular events associated with altered tissue DHA.
authors.affiliation: The Nutrition Research Program, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4.
authors.forename: Julie L
authors.initials: JL
authors.lastname: Pongrac
authors.forename: Penelope J
authors.initials: PJ
authors.lastname: Slack
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Innis
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D039561:Eukaryotic Initiation Factor-4E / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6 / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006321:Heart / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D009206:Myocardium / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011247:Pregnancy; D011494:Protein Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D050600:SNARE Proteins / Q000378:metabolism*; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases
chemical_list: D002352:Carrier Proteins; D004042:Dietary Fats, Unsaturated; C499526:Eif4ebp1 protein, rat; D039561:Eukaryotic Initiation Factor-4E; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D050600:SNARE Proteins; D011494:Protein Kinases; C546845:mTOR protein, rat; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D009584:Nitrogen; D020123:Sirolimus