Journal of Nutrition Nutritional Immunology

A Conjugated Linoleic Acid-Enriched Beef Diet Attenuates Lipopolysaccharide-Induced Inflammation in Mice in Part through PPAR{gamma}-Mediated Suppression of Toll-Like Receptor 4 [Nutritional Immunology]

Fri, 20 Nov 2009 10:01:59 PST

Conjugated linoleic acid (CLA) is a PUFA found in beef and dairy products that has immunoregulatory properties. The level of CLA in beef can be enhanced by feeding cattle fresh grass rather than concentrates. This study determined the effect of feeding a high-CLA beef diet on inflammation in an in vivo model of septic shock. Mice were fed a high-CLA beef (4.3% total fatty acid composition) or low-CLA beef diet (0.84% total fatty acid composition) for 6 wk. Lipopolysaccharide (LPS; 3 µg) or sterile PBS was injected i.v. and serum was harvested 6 h after injection. Serum interleukin (IL)-1β, IL-12p70, IL-12p40, and interferon- concentrations were significantly reduced in response to the LPS challenge in the high-CLA beef diet group. Bone marrow-derived dendritic cells (BMDC) from the high-CLA beef diet group had significantly less IL-12 and more IL-10 in response to ex vivo LPS stimulation. Furthermore, toll-like receptor 4 (TLR4) and CD14 protein and mRNA expression on BMDC was significantly attenuated in the high-CLA compared with the low-CLA beef diet group. Complimentary in vitro experiments to determine the specificity of the effect showed that synthetic cis9, trans11-CLA suppressed surface expression of CD14 and TLR4 on BMDC. Treatment with the PPAR inhibitor GW9662 partially reversed TLR4 expression in immature BMDC. The results of this study demonstrate that feeding a diet enriched in high-beef CLA exerts profound antiinflammatory effects in vivo within the context of LPS-induced sepsis. In addition, downregulation of BMDC TLR4 is mediated through induction of PPAR.

Maternal Milk, but Not Formula, Regulates the Immune Response to {beta}-Lactoglobulin in Allergy-Prone Rat Pups [Nutritional Immunology]

Tue, 20 Oct 2009 10:01:51 PDT

Controversy exists regarding the timing of the introduction of allergic foods into the diet. We investigated the immune response of rat pups exposed to β-lactoglobulin (BLG), one of the main allergenic proteins in cow milk. Brown Norway allergy-prone rats were allocated into groups: dam-reared and unchallenged (DR), DR challenged with BLG via gavage (11 mg/d), or rats fed via gastric cannula a formula containing BLG (11 mg/d). BLG was given from d 4 of life. Rats were killed at d 10, 14, or 21. Sera were assayed for total IgE, BLG-specific IgG1, and rat mucosal mast cell protease II (RMCPII; indicator of mucosal mast cell degranulation). Ileum was assessed for cytokine mRNA. Mesenteric lymph nodes (MLN) were assessed for forkhead boxP3 (Foxp3) and chemokine (C-C motif) receptor 7 (CCR7) expression by real-time PCR and immunostained for Foxp3⁺ CD4⁺ regulatory cells. Formula feeding compared with dam-rearing with or without oral BLG challenge resulted in significantly greater serum IgE, BLG-specific IgG1, RMCPII, and intestinal mast cells but reduced MLN Foxp3⁺ cells, Foxp3, and CCR7 expression and ileal cytokines, interleukin (IL)-4, IL-10, and interferon- (P < 0.05). Importantly, giving BLG in the presence of maternal milk resulted in an immune response profile similar to that of unchallenged DR rats but with greater Foxp3 and CCR7 mRNA expression and CD4⁺ Foxp3⁺ cells (P < 0.05). We conclude that introducing an allergenic food with breast milk reduces immunological indicators of an allergic response, whereas introduction during formula feeding generates an allergic response.

Bacillus polyfermenticus Ameliorates Colonic Inflammation by Promoting Cytoprotective Effects in Colitic Mice [Nutritional Immunology]

Im, E., Choi, Y. J., Pothoulakis, C., Rhee, S. H. — Fri, 18 Sep 2009 10:01:30 PDT

Although human consumption of Bacillus polyfermenticus provides several health benefits, the probiotic effect of this bacterium against colonic inflammation has not yet, to our knowledge, been studied. Therefore, we induced colitis in mice by oral or intrarectal administration of dextran sodium sulfate (DSS) or trinitrobenzenosulfonic acid (TNBS), respectively, and investigated the effect of B. polyfermenticus on colitis. We found that mice treated with DSS or TNBS along with B. polyfermenticus had reduced mortality and severity of colitis (weight loss, diarrhea, and mucosal damages) than mice treated with DSS or TNBS alone. B. polyfermenticus also reduced the expression of inflammatory molecules, including chemokine (C-X-C motif) ligand 1, intercellular adhesion molecule, and tumor necrosis factor-, but enhanced the expression of the antiinflammatory cytokine interleukin-10 in the inflamed mouse colon. Moreover, B. polyfermenticus suppressed apoptosis both in vivo in inflamed colonic mucosa and in vitro in colonic epithelial cells stimulated with apoptosis-inducing agents (FasL or Clostridium difficile Toxin A) when the apoptotic response was determined by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay and cleavage of poly(ADP-ribose) polymerase or caspase-3, respectively. Treating colonic epithelial cells with B. polyfermenticus-conditioned medium (BPCM) enhanced cell proliferation and induced the phosphoinositide 3-kinases/Akt signaling pathway, suggesting that this bacterium can promote epithelial cell proliferation. BPCM also promoted the migration of colonic epithelial cells. These data suggest that B. polyfermenticus ameliorates colonic inflammation by suppressing apoptosis and promoting epithelial cell proliferation and migration.

Polymorphisms at Cytokine Genes May Determine the Effect of Vitamin E on Cytokine Production in the Elderly [Nutritional Immunology]

Fri, 18 Sep 2009 10:01:30 PDT

Vitamin E has been shown to affect cytokine production. However, individual response to vitamin E supplementation varies. Previous studies indicate that cytokine production is heritable and common single nucleotide polymorphisms (SNP) may explain differences in cytokine production between individuals. We hypothesize that the differential response to the immunomodulatory actions of vitamin E reflects genetic differences among individuals, including SNP at cytokine genes that modulate cytokine production. We used data from a double-blind, placebo-controlled 1-y vitamin E (182 mg d,l--tocopherol) intervention study in elderly men and women (mean age 83 y) to test this hypothesis (vitamin E, n = 47; placebo, n = 63). We found that the effect of vitamin E on tumor necrosis factor (TNF)- production in whole blood stimulated for 24 h with lipopolysaccharide (1.0 mg/L) is dependent on TNF -308G > A. Participants with the A/A and A/G genotypes at TNF -308G > A who were treated with vitamin E had lower TNF production than those with the A allele treated with placebo. These observations suggest that individual immune responses to vitamin E supplementation are in part mediated by genetic factors. Because the A allele at TNF has been previously associated with higher TNF levels in whole blood and isolated immune cells, our observations suggest that the antiinflammatory effect of vitamin E is specific to those genetically predisposed to higher inflammation. Further studies are needed to determine the biological mechanism driving the interaction between vitamin E treatment and TNF -308G > A and its implications for disease resistance.

9E,11E-Conjugated Linoleic Acid Increases Expression of the Endogenous Antiinflammatory Factor, Interleukin-1 Receptor Antagonist, in RAW 264.7 Cells [Nutritional Immunology]

Lee, Y., Thompson, J. T., Vanden Heuvel, J. P. — Fri, 18 Sep 2009 10:01:30 PDT

Despite having a similar structure, various conjugated linoleic acid (CLA) isomers have a distinct gene expression pattern in RAW 264.7 (RAW) cells, a mouse macrophage cell line. Among the 5 CLA isomers tested [9cis(Z),11trans(E)-, 9Z,11Z-, 9E,11E-, 10E,12Z-, and 11Z,13E-CLA], only 9E,11E-CLA induced the endogenous antiinflammatory molecule, interleukin (IL)-1 receptor antagonist (IL-1Ra), in RAW cells. In this study, the mechanism and effects of IL-1Ra regulation by 9E,11E-CLA in RAW cells was studied in detail. 9E,11E-CLA induced IL-1Ra in a dose- and time-dependent manner, whereas it decreased lipopolysaccharide (LPS)-induced IL-1, IL-1β, and IL-6 mRNA levels and protein levels. To determine the importance of IL-1Ra in the antiinflammatory effects of this particular CLA isomer, IL-1Ra protein levels were repressed in RAW cells using small interference RNA inhibitor expression. In the presence of IL-1Ra small interference RNA, the induction of this molecule was ablated, as was the decrease of LPS-induced IL-1 and IL-6 mRNA levels by 9E,11E-CLA. The IL-1Ra increase due to this CLA isomer was transcriptionally regulated, although there was no response element(s) affected by 9E,11E-CLA in the first 1.5 kb of the IL-1Ra promoter. The phosphoinositide 3-kinase inhibitors, LY294002 and the mammalian target of rapamycin inhibitor rapamycin, abolished the IL-1Ra induction by 9E,11E-CLA, whereas other kinase inhibitors did not affect this response. Taken together, 9E,11E-CLA exerts unique antiinflammatory effects by increasing an endogenous repressor of IL-1 signaling.