Arachidonic acid and prostacyclin signaling promote adipose tissue development: a human health concern?

High fat intake is associated with fat mass gain through fatty acid activation of peroxisome proliferator-activated receptors δ and γ, which promote adipogenesis. We show herein that, compared to a combination of specific agonists to both receptors or to saturated, monounsaturated, and ω-3 polyunsaturated fatty acids, arachidonic acid (C20:4, ω-6) promoted substantially the differentiation of clonal preadipocytes. This effect was blocked by cyclooxygenase inhibitors and mimicked by carbacyclin, suggesting a role for the prostacyclin receptor and activation of the cyclic AMP-dependent pathways that regulate the expression of the CCAAT enhancer binding proteins β and δ implicated in adipogenesis. During the pregnancy-lactation period, mother mice were fed either a high-fat diet rich in linoleic acid, a precursor of arachidonic acid (LO diet), or the same isocaloric diet enriched in linoleic acid and α-linolenic acid (LO/LL diet). Body weight from weaning onwards, fat mass, epididymal fat pad weight, and adipocyte size at 8 weeks of age were higher with LO diet than with LO/LL diet. In contrast, prostacyclin receptor-deficient mice fed either diet were similar in this respect, indicating that the prostacyclin signaling contributes to adipose tissue development.These results raise the issue of the high content of linoleic acid of i) ingested lipids during pregnancy and lactation, and ii) formula milk and infant foods in relation to the epidemic of childhood obesity. High fat intake is associated with fat mass gain through fatty acid activation of peroxisome proliferator-activated receptors δ and γ, which promote adipogenesis. We show herein that, compared to a combination of specific agonists to both receptors or to saturated, monounsaturated, and ω-3 polyunsaturated fatty acids, arachidonic acid (C20:4, ω-6) promoted substantially the differentiation of clonal preadipocytes. This effect was blocked by cyclooxygenase inhibitors and mimicked by carbacyclin, suggesting a role for the prostacyclin receptor and activation of the cyclic AMP-dependent pathways that regulate the expression of the CCAAT enhancer binding proteins β and δ implicated in adipogenesis. During the pregnancy-lactation period, mother mice were fed either a high-fat diet rich in linoleic acid, a precursor of arachidonic acid (LO diet), or the same isocaloric diet enriched in linoleic acid and α-linolenic acid (LO/LL diet). Body weight from weaning onwards, fat mass, epididymal fat pad weight, and adipocyte size at 8 weeks of age were higher with LO diet than with LO/LL diet. In contrast, prostacyclin receptor-deficient mice fed either diet were similar in this respect, indicating that the prostacyclin signaling contributes to adipose tissue development. These results raise the issue of the high content of linoleic acid of i) ingested lipids during pregnancy and lactation, and ii) formula milk and infant foods in relation to the epidemic of childhood obesity. Obesity is associated with metabolic disorders such as dyslipidemia, diabetes, and hypertension, and fat mass excess in severe obesities is typically due to an increase in adipocyte size and number. The formation of adipocytes is a critical event, as mature adipocytes do not divide in vivo and do not undergo significant turnover under physiological conditions. The capacity for proliferation of precursor cells and their differentiation into adipocytes is highest at early age and decrease thereafter in humans and rodents. A limited number of hormones can affect the adipose tissue mass and possibly its distribution (1Ailhaud G. Hauner H. Development of white adipose tissue.in: Bray G. Bouchard C. James P.T. Handbook of Obesity. M. Dekker Inc., New York, NY1997: 359-378Google Scholar). High dietary fat intake is now recognized to be associated with a gain of fat mass in animals and humans at all ages (2Troiano R.P. Briefel R.R. Carrol D.M. Bialostosky K. Energy and fat intakes of children and adolescents in the United States: data from the National Health and Nutrition examination surveys.Am. J. Clin. Nutr. 2000; 72: 1343S-1353SGoogle Scholar, 3Oscai L.B. Brown N.M. Miller W.C. Effect of dietary fat on food intake, growth and body composition in rats.Growth. 1984; 48: 415-424Google Scholar, 4Romieu I. Willett W.C. Stampfer M.J. Colditz G.A. Sampson L. Rosner B. Hennckens C.H. Speizer F.E. Energy intake and other determinants of relative weight.Am. J. Clin. Nutr. 1988; 74: 406-412Google Scholar, 5Nguyen T. Larson D.E. Johnson R.K. Goran M.I. Fat intake and adiposity in children of lean and obese parents.Am. J. Clin. Nutr. 1996; 63: 507-513Google Scholar). However, the lack of evidence of a general increase in energy intake as fat among youths, despite a striking increase in the prevalence of obesity in industrial and developing countries, may be due in part to decreased physical activity and nonexercise activity thermogenesis (6Levine J.A. Eberhardt N.L. Jensen M.D. Role of nonexercise activity thermogenesis in resistance to fat gain in humans.Science. 1999; 283: 212-214Google Scholar), but also to the composition of food intake in early life. The long-term relationship between the fatty acid composition of dietary fats and the development of adipose tissue in humans is difficult to assess in contrast to animals. When mother rats were fed a high-fat diet rich in linoleic acid (C18:2, ω-6) or saturated fatty acids, suckling pups at 17 days of age exhibited hyperplasia or hypertrophy of white adipose tissue, respectively (7Clearly M.P. Philips F.C. Morton A.A. Genotype and diet effects in lean and obese Zucker rats fed either safflower or coconut oil diets.Proc. Soc. Exp. Biol. Med. 1999; 220: 153-161Google Scholar). Moreover, fish oil rich in eicosapentaenoic acid (C20:5, ω-3, EPA) and docosahexaenoic acid (C22:6, ω-3, DHA) prevents obesity in rats (8Parrish C.C. Pathy D.A. Angel A. Dietary fish oils limit adipose tissue hypertrophy in rats.Metabolism. 1990; 39: 217-219Google Scholar, 9Raclot T. Groscolas R. Langin D. Ferré P. Site-specific regulation of gene expression by n-3 polyunsaturated fatty acids in rat white adipose tissues.J. Lipid Res. 1997; 38: 1963-1972Google Scholar), as well as feeding rats after weaning with dietary fats rich in α-linolenic acid (C18:3, ω-3), the precursor of EPA and DHA, prevents excessive growth of adipose tissue (10Okuno M. Kajiwara K. Imai S. Kobayashi T. Honma N. Maki T. Suruga K. Goda T. Takase S. Muto Y. Moriwaki H. Perilla oil prevents the excessive growth of visceral adipose tissue in rats by down-regulating adipocyte differentiation.J. Nutr. 1997; 127: 1752-1757Google Scholar). The mechanisms underlying the differential adipogenic effect of ω-6 versus ω-3 polyunsaturated fatty acids suggest differences between fatty acids and/or fatty acid metabolites in promoting differentiation of adipose precursor cells into adipocytes. In vitro, at the preadipocyte stage, a member of the peroxisome proliferator-activated receptor (PPAR) family, i.e., PPARδ, and two members of the CCAAT-enhancer binding protein family, i.e., C/EBPβ and C/EBPδ, act concomitantly to upregulate the subsequent and critical expression of PPARγ leading to adipogenesis (11Barak Y. Nelson M.C. Ong E.S. Jones Y.Z. Ruiz-Lozano P. Chien K.R. Kader A. Evans R.M. PPARγ is required for placental, cardiac, and adipose tissue development.Mol. Cell. 1999; 4: 585-595Google Scholar, 12Kubota N. Terauchi Y. Miki H. Tamemoto H. Yamauchi T. 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S. and in mice prostacyclin 1997; Scholar), and were to and mice were on a with from to at The mice to be were fed either a diet which of and or a high-fat diet oil (LO or a of oil and oil (LO/LL diet). high-fat of and and were with and oil in of fatty acids, saturated, monounsaturated, ω-6 and ω-3 polyunsaturated fatty The of oil and oil saturated, monounsaturated, ω-6 and ω-3 polyunsaturated fatty 8 weeks of mice fed the same diet weaning were to mice and and on the same diet. days of pups were the same that their and intake, body weight, body and of epididymal fat pad were as J. A. A. S. P. A. R. Ailhaud G. M. mice of diet-induced weight gain with in adipose tissue development and Scholar). were in with the of the of from and mice at were to after and were into adipocytes as N. P. B. P. J. J. K. A. S. Ailhaud G. C. of and the expression of C/EBPβ and in Scholar). of cells were in with and as D. R. M. Ailhaud G. and role of arachidonic acid in the differentiation of preadipose J. Scholar). were after growth and differentiation of cells in as D. R. M. Ailhaud G. and role of arachidonic acid in the differentiation of preadipose J. Scholar). Fatty acids, and were in and at a into which not effect on either adipose or cyclic was as D. R. M. Ailhaud G. and role of arachidonic acid in the differentiation of preadipose J. Scholar). were in at after D. R. M. Ailhaud G. and role of arachidonic acid in the differentiation of preadipose J. Scholar). cyclic was with a by to the cyclic was with of the and of the was in a were in of and at in were on by the We in preadipocytes for days to in the the of various was in cells to the ω-6 compared with ω-3 which is at in dietary fat in the of ω-6 was was as a cyclooxygenase polyunsaturated fatty acid of the ω-3 DHA, to ω-3 In with R. D. Ailhaud G. as a of adipose J. Scholar), carbacyclin, a prostacyclin that to the prostacyclin receptor was adipogenic activity than a specific (17Xu H.E. Lambert M.H. Montana V.G. Parks D.J. Blanchard S.G. Brown P.J. Sternbach D.D. Lehmann J.M. Wisely G.B. Willson T.M. Kliewer S.A. Milburn M.V. Molecular recognition of fatty acids by peroxisome proliferator-activated receptors.Mol. Cell. 1999; 3: 397-403Google or a combination of and a specific PPARγ J.M. Moore L.B. Willson T.M. Kliewer S.A. is a high for peroxisome proliferator-activated receptor Biol. In to at which ω-6 was in the differentiation adipose in the of of and/or PPARγ an adipocyte The of agonists was i) in cells that can be into the adipose i.e., and but not the adipocyte binding protein or C. Milstone D.S. C. N. B. B. P. E. P. Mortensen R.M. Ailhaud G. C. and effects on the development of adipose cells from 2002; ii) is at in early in contrast to which is during adipogenesis Ailhaud G. N. Grimaldi of a protein that mediates transcriptional effects of fatty acids in preadipocytes. to peroxisome proliferator-activated Biol. and activation of by is required to upregulate the expression of PPARγ C. S. D. C. Grimaldi P. of peroxisome proliferator-activated receptor of PPARγ and adipocyte differentiation in Biol. 1999; Scholar, H. R.K. K. proliferator-activated receptor δ regulation of preadipocyte proliferation and gene expression is on Biol. Scholar). with of the from to by its and of the PPARγ from to to be was similar to that in the of both agonists between and In contrast, or to either for days was in promoting adipogenesis part the PPARγ was from to the adipogenic of ω-6 during the days was higher than that of the and this effect was after cyclooxygenase part In contrast to ω-6 and carbacyclin, the adipogenic of ω-3 and were in the of the between and ω-6 and ω-3 exhibited an adipogenic similar to that of the PPARγ part results show that the effect of ω-6 at early of the differentiation in with the that not prostacyclin and through in cells G. D. Ailhaud G. R. is a specific of adipose its role as a and Biol. of adipogenesis by agonists and long-chain fatty from to from to of versus versus versus versus ω-6 versus ω-6 versus ω-6 versus ω-3 versus ω-3 versus ω-3 versus versus versus versus versus versus versus versus EPA to be on a long-term versus versus arachidonic δ as of on of of versus versus EPA to be on a long-term in a arachidonic δ as of on of In to gain into the role of adipogenesis of from and mice N. P. B. P. J. J. K. A. S. Ailhaud G. C. of and the expression of C/EBPβ and in was compared by a combination of a specific of but to J. P. N. C. R. Ailhaud G. receptor the early expression of C/EBPβ and in preadipose Cell. 2000; Scholar), and the PPARγ was decreased in compared with that of to a combination of and PPARγ not adipogenesis that with the PPARγ not expression of C/EBPβ and was in in to N. P. B. P. J. J. K. A. S. Ailhaud G. C. of and the expression of C/EBPβ and in Scholar), that the adipogenic of was due to its as a of and activation of the leading in to C/EBPβ and expression and of PPARγ expression N.L. of peroxisome proliferator-activated receptor during the of into adipocytes is by and Cell. Biol. 1996; 16: Scholar), and as a of The of various long-chain fatty acids to early of differentiation was in preadipocytes to the PPARγ part A saturated fatty acid or fatty acids and was adipogenic compared with ω-6 two ω-3 polyunsaturated fatty acids, EPA and DHA, were also The higher adipogenic activity of ω-6 compared with other fatty acids be to its higher for PPARδ, as the arachidonic acid, saturated, monounsaturated, and ω-3 polyunsaturated fatty acids with similar (17Xu H.E. Lambert M.H. Montana V.G. Parks D.J. Blanchard S.G. Brown P.J. Sternbach D.D. Lehmann J.M. Wisely G.B. Willson T.M. Kliewer S.A. Milburn M.V. Molecular recognition of fatty acids by peroxisome proliferator-activated receptors.Mol. Cell. 1999; 3: 397-403Google Scholar). ω-6 was among fatty acids in promoting adipocyte compared cyclic after a of preadipocytes to of the various long-chain fatty acids ω-6 cyclic by in in and this effect was by cyclooxygenase cyclic by as with activity was and in the of ω-6 and respectively not ω-3 DHA, acid, acid, acid, or PPARγ effect on cyclic In to ω-3 polyunsaturated fatty acids were not adipogenic to and/or PPARγ activity in the of ω-3 was compared with that in the of agonists PPARs as of ω-3 not in preadipocytes the effect on cyclic of ω-3 polyunsaturated fatty acids that to the cyclic AMP-dependent B. Brown L.B. E.J. by ω-3 fatty Biol. Scholar). In the of ω-6 of ω-3 or cyclic by and in the of ω-6 a of this was by of EPA These results suggest that ω-3 polyunsaturated fatty acids in preadipocytes the cyclic pathways by arachidonic acid at of cyclic by arachidonic acid and various of as of of on of Fatty acids and to fatty were at δ as of of on of Fatty acids and to fatty were at δ in a the fatty acid composition of high-fat adipose tissue in and We a diet rich in linoleic acid, a fatty acid precursor of arachidonic acid (LO compared with an isocaloric diet enriched with a of oil and oil rich in α-linolenic acid, fatty acid precursor of EPA and (LO/LL diet). The mice to be were fed either LO diet or LO/LL diet from weeks of weeks mice were to mice and on the same diet. were with their weaning and on the same weaning to weeks of body weight of mice fed LO diet was higher than that of animals fed LO/LL diet and this to a at the age a similar food intake the body weight of mice on either of was the of food intake was also similar despite differences in intake, this thermogenesis in mice fed a high-fat diet. Moreover, body weight of mice was fed LO diet or LO/LL the critical role of ω-6 polyunsaturated fatty acids in body weight gain during pregnancy and/or the suckling was in body between and mice fed either of fat mass and epididymal fat pad weight of and mice at 8 weeks of age Fat mass of mice fed diet or LO/LL diet was that of animals fed LO diet was In contrast, fat mass was in mice fed either diet. with epididymal fat pad weight of mice was higher in mice fed LO diet than in mice fed LO/LL diet or diet. was significant in the epididymal fat pad of mice fed either of size of epididymal fat pad was in mice fed LO diet compared with the two other and this was by a decrease of adipocyte number with adipocyte size was decreased and adipocyte number was in mice fed was in adipocyte size and number of the epididymal fat pad of mice fed either diet mother mice were fed a diet and pups were fed after weaning a LO or LO/LL body weight of animals fed LO diet was not higher than that of fed LO/LL the of linoleic diet during the pregnancy-lactation intake, fat mass, and epididymal fat pad weight in and mice fed either a diet or a high-fat diet enriched with linoleic acid or enriched with linoleic acid and α-linolenic acids intake fat mass versus fat versus versus versus in a number and size in epididymal fat pad of and mice in fed after weaning to a diet LO or LO/LL diet. as versus fed a diet. versus fed LO versus fed LO/LL The development of adipose tissue on the of pathways that upregulate the expression of This expression on the expression of C/EBPβ and N.L. of peroxisome proliferator-activated receptor during the of into adipocytes is by and Cell. Biol. 1996; 16: and of both the formation of adipose tissue T. N. T. S. adipocyte differentiation in mice the C/EBPβ and/or J. 1997; 16: Scholar). We that the expression of C/EBPβ and in i.e., and its receptor the J. S. N. M. L. P. B. A. Ailhaud G. C. and its receptor promote adipocyte differentiation the protein Biol. 1999; and the the N. P. B. P. J. J. K. A. S. Ailhaud G. C. of and the expression of C/EBPβ and in Scholar). results show that polyunsaturated fatty acids of the ω-6 adipogenic both in and in vivo compared with their ω-3 ω-6 is prostacyclin in the the other ω-3 polyunsaturated fatty acids do not affect this as well as prostaglandin a synthesized from EPA on pathways and on the role of arachidonic acid and other long-chain fatty acids in promoting adipogenesis. In of results from in a high-fat diet rich in linoleic acid arachidonic acid formation through prostacyclin cyclic AMP-dependent signaling pathways in preadipocytes. This the formation of mature adipocytes is to with the high exogenous of fatty In contrast, in mice fed a high-fat diet a of linoleic and α-linolenic acids, the of cyclic may limit the formation of leading to hyperplasia to the fatty acid This of cyclic be due to a decreased arachidonic acid from linoleic acid through of activity by α-linolenic acid and its metabolites A. N. oil activity in in a dietary to mice of arachidonic Nutr. 1997; Scholar). In activation of the through the prostacyclin and the adipogenic effect of ω-6 and ω-3 polyunsaturated fatty acids is prostacyclin in in adipose tissue mass was between mice fed LO or LO/LL suggesting that the activation of by significant on the differentiation that of α-linolenic acid in an isocaloric diet rich in linoleic acid prevents the of fat mass is with in the of fatty acids the of arachidonic acid versus EPA and A. N. oil activity in in a dietary to mice of arachidonic Nutr. 1997; and to in the of adipose tissue development which during pregnancy and the suckling in the size was in mice fed either pups from mother mice fed LO diet at than from mice fed LO/LL diet. This an issue in as adipose tissue is during the of and of its development of age (1Ailhaud G. Hauner H. Development of white adipose tissue.in: Bray G. Bouchard C. James P.T. Handbook of Obesity. M. Dekker Inc., New York, NY1997: 359-378Google Scholar). In this respect, the prevalence among children of to of age in from in through to in and in from to during the same of R.P. Briefel R.R. Johnson of among children in the United through 1997; Scholar). is of to that the content of linoleic acid of mature milk of a of their fat intake, from to between and despite the that the of linoleic acid to α-linolenic acid in mature milk of and is is also to that the of arachidonic acid to is higher in the milk of due to its content Fatty acids and Jensen The of Inc., Scholar, The lipids in Lipid Res. 1997; 35: Scholar, in 1999; Scholar). that feeding may decrease the prevalence of and obesity in childhood R. B. T. E. D. H. feeding and 1999; M.W. A.E. Colditz G.A. of among adolescents were as Scholar). the was to the energy intake of D.A. Energy intake, not energy is a of body size in J. Clin. Nutr. 1999; Scholar), the fatty acid composition be as the of linoleic acid is by in infant formula compared with milk P. P. C. M. B. G. C. of docosahexaenoic and arachidonic acids at their relative in fed milk or J. Clin. Nutr. 1999; Scholar). We suggest that, at a early age energy similar between of linoleic acid during suckling period, and early determinants of physiological implicated at a adipose tissue is in a of its and that to childhood obesity. This was by from Nutrition and by a from the and by a from the National to due to G. for to C. for and to R. for critical of the and were of S. and and was a of N. The the of oil from Inc., adipocyte binding protein protein A