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Dietary fish oil and DHA down-regulate antigen-activated CD4⁺ T-cells while promoting the formation of liquid-ordered mesodomains

Kim, Wooki, Barhoumi, Rola, McMurray, David N., Chapkin, Robert S.
The British journal of nutrition 2014 v.111 no.2 pp. 254-260
CD4-positive T-lymphocytes, corn oil, dietary nutrient sources, fish oils, gangliosides, immunological synapse, liquid membranes, mice, omega-3 fatty acids, ovalbumin, plasma membrane, polyunsaturated fatty acids, protein kinase C, transgenic animals
We have demonstrated previously that n-3 PUFA endogenously produced by fat-1 transgenic mice regulate CD4⁺ T-cell function by affecting the formation of lipid rafts, liquid-ordered mesodomains in the plasma membrane. In the present study, we tested the effects of dietary sources of n-3 PUFA, i.e. fish oil (FO) or purified DHA, when compared with an n-6 PUFA-enriched maize oil control diet in DO11.10 T-cell receptor transgenic mice. Dietary n-3 PUFA were enriched in CD4⁺ T-cells, resulting in the increase of the n-3:n-6 ratio. Following antigen-specific CD4⁺ T-cell activation by B-lymphoma cells pulsed with the ovalbumin 323–339 peptide, the formation of liquid-ordered mesodomains at the immunological synapse relative to the whole CD4⁺ T-cell, as assessed by Laurdan labelling, was increased (P< 0·05) in the FO-fed group. The FO diet also suppressed (P< 0·05) the co-localisation of PKCθ with ganglioside GM1 (monosialotetrahexosylganglioside), a marker for lipid rafts, which is consistent with previous observations. In contrast, the DHA diet down-regulated (P< 0·05) PKCθ signalling by moderately affecting the membrane liquid order at the immunological synapse, suggesting the potential contribution of the other major n-3 PUFA components of FO, including EPA.