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Neither linoleic acid nor arachidonic acid promote white adipose tissue inflammation in Fads2-/- mice fed low fat diets.

Abstract

Dietary n-6 polyunsaturated fatty acids (PUFA) are widely perceived to promote inflammation and contribute to the development of chronic diseases. This dogma has been recently questioned due to evidence that n-6 PUFA, specifically linoleic acid (LA, 18:2n-6) and arachidonic acid (AA, 20:4n-6), do not appear to activate inflammatory signalling pathways when consumed in moderate amounts. However, delineating the independent roles of different dietary n-6 PUFA in vivo is challenging because LA is continuously converted into AA in a pathway regulated by the fatty acid desaturase 2 (Fads2) gene. The objective of this study was to investigate the independent roles of LA and AA on white adipose tissue (WAT) inflammatory signalling pathways using Fads2-/- mice. We hypothesized that dietary LA would not induce WAT inflammation, unless it was endogenously converted into AA. Male C57BL/6 wild-type (WT) and Fads2-/- mice were fed low-fat isocaloric diets containing either 7% corn oil w/w (CD, containing ~42% LA) or 7% ARASCO oil w/w (AD, containing ~27% AA) for 9 weeks. WAT inflammatory gene expression, protein levels, as well as phospholipid (PL) and triacylglycerol (TAG) fatty acid composition, were analyzed by RT-qPCR, western blots, and gas chromatography, respectively. Fads2-/- mice fed CD had high LA, but little-to-no GLA (18:3n-6), DGLA (20:3n-6), and AA in PLs and TAGs compared to their WT counterparts. In comparison, Fads2-/- and WT mice fed AD showed minimal differences in n-6 PUFA content in serum and WAT, despite having significantly more AA than CD-fed mice. No differences in gene expression for common inflammatory adipokines (e.g. Mcp-1, Ccl5, Tnfα) or key regulators of eicosanoid production (e.g. Cox-2, Alox-12, Alox-15) were detected in WAT between any of the diet and genotype groups. Furthermore, no differences in MCP-1, and total or phosphorylated STAT3 and p38 inflammatory proteins, were observed. Collectively, these results demonstrate that neither LA nor AA promote WAT inflammation when consumed as part of a low-fat diet. Therefore, the existing dogma surrounding n-6 PUFA and inflammation needs to be reconsidered.

Authors+Show Affiliations

Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1.Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1.Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1.Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1.Division of Nutritional Sciences, University of Illinois, 905 South Goodwin Avenue, Urbana, IL 61801, USA.Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1.Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd. E., Guelph, ON, Canada N1G2W1. Electronic address: dmutch@uoguelph.ca.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29031400

Citation

Suitor, Katherine, et al. "Neither Linoleic Acid nor Arachidonic Acid Promote White Adipose Tissue Inflammation in Fads2-/- Mice Fed Low Fat Diets." Prostaglandins, Leukotrienes, and Essential Fatty Acids, vol. 126, 2017, pp. 84-91.
Suitor K, Payne GW, Sarr O, et al. Neither linoleic acid nor arachidonic acid promote white adipose tissue inflammation in Fads2-/- mice fed low fat diets. Prostaglandins Leukot Essent Fatty Acids. 2017;126:84-91.
Suitor, K., Payne, G. W., Sarr, O., Abdelmagid, S., Nakamura, M. T., Ma, D. W., & Mutch, D. M. (2017). Neither linoleic acid nor arachidonic acid promote white adipose tissue inflammation in Fads2-/- mice fed low fat diets. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 126, pp. 84-91. doi:10.1016/j.plefa.2017.09.008.
Suitor K, et al. Neither Linoleic Acid nor Arachidonic Acid Promote White Adipose Tissue Inflammation in Fads2-/- Mice Fed Low Fat Diets. Prostaglandins Leukot Essent Fatty Acids. 2017;126:84-91. PubMed PMID: 29031400.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Neither linoleic acid nor arachidonic acid promote white adipose tissue inflammation in Fads2-/- mice fed low fat diets. AU - Suitor,Katherine, AU - Payne,George W, AU - Sarr,Ousseynou, AU - Abdelmagid,Salma, AU - Nakamura,Manabu T, AU - Ma,David Wl, AU - Mutch,David M, Y1 - 2017/09/15/ PY - 2017/07/19/received PY - 2017/09/11/revised PY - 2017/09/11/accepted PY - 2017/10/17/entrez PY - 2017/10/17/pubmed PY - 2018/6/1/medline KW - Arachidonic acid KW - Delta-6 desaturase KW - Epididymal fat KW - Inflammation KW - Inguinal fat KW - Linoleic acid SP - 84 EP - 91 JF - Prostaglandins, leukotrienes, and essential fatty acids JO - Prostaglandins Leukot. Essent. Fatty Acids VL - 126 N2 - Dietary n-6 polyunsaturated fatty acids (PUFA) are widely perceived to promote inflammation and contribute to the development of chronic diseases. This dogma has been recently questioned due to evidence that n-6 PUFA, specifically linoleic acid (LA, 18:2n-6) and arachidonic acid (AA, 20:4n-6), do not appear to activate inflammatory signalling pathways when consumed in moderate amounts. However, delineating the independent roles of different dietary n-6 PUFA in vivo is challenging because LA is continuously converted into AA in a pathway regulated by the fatty acid desaturase 2 (Fads2) gene. The objective of this study was to investigate the independent roles of LA and AA on white adipose tissue (WAT) inflammatory signalling pathways using Fads2-/- mice. We hypothesized that dietary LA would not induce WAT inflammation, unless it was endogenously converted into AA. Male C57BL/6 wild-type (WT) and Fads2-/- mice were fed low-fat isocaloric diets containing either 7% corn oil w/w (CD, containing ~42% LA) or 7% ARASCO oil w/w (AD, containing ~27% AA) for 9 weeks. WAT inflammatory gene expression, protein levels, as well as phospholipid (PL) and triacylglycerol (TAG) fatty acid composition, were analyzed by RT-qPCR, western blots, and gas chromatography, respectively. Fads2-/- mice fed CD had high LA, but little-to-no GLA (18:3n-6), DGLA (20:3n-6), and AA in PLs and TAGs compared to their WT counterparts. In comparison, Fads2-/- and WT mice fed AD showed minimal differences in n-6 PUFA content in serum and WAT, despite having significantly more AA than CD-fed mice. No differences in gene expression for common inflammatory adipokines (e.g. Mcp-1, Ccl5, Tnfα) or key regulators of eicosanoid production (e.g. Cox-2, Alox-12, Alox-15) were detected in WAT between any of the diet and genotype groups. Furthermore, no differences in MCP-1, and total or phosphorylated STAT3 and p38 inflammatory proteins, were observed. Collectively, these results demonstrate that neither LA nor AA promote WAT inflammation when consumed as part of a low-fat diet. Therefore, the existing dogma surrounding n-6 PUFA and inflammation needs to be reconsidered. SN - 1532-2823 UR - https://www.unboundmedicine.com/medline/citation/29031400/Neither_linoleic_acid_nor_arachidonic_acid_promote_white_adipose_tissue_inflammation_in_Fads2_/__mice_fed_low_fat_diets_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0952-3278(17)30185-0 DB - PRIME DP - Unbound Medicine ER -