Dietary n-6 PUFA deprivation downregulates arachidonate but upregulates docosahexaenoate metabolizing enzymes in rat brain

作者：Kim Hyung Wook^*; Rao Jagadeesh S; Rapoport Stanley I; Igarashi Miki

来源：Biochimica et Biophysica Acta-Molecular and Cell Biology of Lipids, 2011, 1811(2): 111-117.

DOI：10.1016/j.bbalip.2010.10.005

• Arachidonic
• Brain
• PUFA
• Phospholipase
• Lipoxygenase
• SREBP

Background: Dietary n-3 polyunsaturated fatty acid (PUFA) deprivation increases expression of arachidonic acid (AA 20:4n-6)-selective cytosolic phospholipase A(2) (cPLA(2)) IVA and cyclooxygenase (COX)-2 in rat brain, while decreasing expression of docosahexaenoic acid (DHA 22:6n-3)-selective calcium-independent iPLA(2) VIA. Assuming that these enzyme changes represent brain homeostatic responses to deprivation, we hypothesized that dietary n-6 PUFA deprivation would produce changes in the opposite directions. Methods: Brain expression of PUFA-metabolizing enzymes and their transcription factors was quantified in male rats fed an n-6 PUFA adequate or deficient diet for 15 weeks post-weaning. Results: The deficient compared with adequate diet increased brain mRNA, protein and activity of iPLA(2) VIA and 15-lipoxygenase (LOX), but decreased cPLA(2) IVA and COX-2 expression. The brain protein level of the iPLA(2) transcription factor SREBP-1 was elevated, while protein levels were decreased for AP-2 alpha and NF-kappa B p65, cPLA(2) and COX-2 transcription factors, respectively. Conclusions: With dietary n-6 PUFA deprivation, rat brain PUFA metabolizing enzymes and some of their transcription factors change in a way that would homeostatically dampen reductions in brain n-6 PUFA concentrations and metabolism, while n-3 PUFA metabolizing enzyme expression is increased. The changes correspond to reported in vitro enzyme selectivities for AA compared with DHA. Published by Elsevier B.V.

• 出版日期2011-2