Location: Diet, Genomics and Immunology Laboratory2018 Annual Report
The overall goal of the project is to elucidate the molecular and cellular mechanisms that respond to selected food components to reduce the risk of chronic diseases such as cancer and obesity, with a focus on immune modulation in relation to obesity. A secondary aim is to further develop the utility of a porcine model to test the effect of probiotics and prebiotics on health maintenance through modulation of the gut microbiome and metabolome. Objective 1. Validate protective effects of bioactive food components such as glyceollins, indoles, and isothiocyanates on development of prostate cancer, and elucidate the regulation of sex steroid hormone-dependent pathways and cancer cell-stromal cell interactions as mechanisms of action by these bioactive food components. (NP107; C3, PS3B, C4, PS 4B) Objective 2. Study, in a swine model or other models as approriate, diet and gut microbiome interactions, focusing on the role of Lactobacillus, Bifidobacterium, and Bacteroides species, for the prevention of obesity and obesity-related metabolic syndrome. (NP107; C3, PS3B, C4, PS 4B)
For Objective 1, a complementary cell culture and tumor xenograft model will be used to test and identify efficacies of bioactive compounds from the diet and elucidate the mechanisms of how these bioactive food components act. The research is expected to identify mechanisms where food components alter biological processes such as proliferation, apoptosis, cell cycles, intracellular cell signaling, inflammation, metastasis, and post-transcriptional message regulation from both cell culture and whole animal studies. Genes involved in pathways mediated by the sex steroid hormones estrogen and androgen, orphan receptors, and cytokine-mediated pathways will be characterized. The conditions that modulate these pathways will include the use of plants with different phytochemical composition to delineate the role of specific compounds along with related food matrix effects. For Objective 2, a juvenile porcine animal model as a surrogate model for humans will be used to validate the effect of selected prebiotics and probiotics on the modulation of the host immune and metabolic responses to an obesogenic diet. The research will use a whole nutrigenomic approach where transcriptomics, metabolomic and metagenomic changes are integrated to identify biomarkers associated with health and disease that can be used as targets for nutritional interventions. Data generated from these studies is expected to reveal mechanisms of action of prebiotic and probiotic products added to the diet.
We continue our efforts to identify active components in the diet, as well as mechanisms of action that may contribute to the protective effects of diet on preventable diseases including cancer, obesity, and inflammation. Progress for Objective 1 is as follows: For Hypothesis 1.2, we followed up on the molecular analysis of our xenograft study on the cruciferous-derived phytochemical, indole-3-carbinol. We previously found that the tumor volume of androgen-dependent LNCaP human prostate carcinomas xenograft was significantly reduced in immunodeficient mice (6- 8 weeks old, male, Balb c/c nu/nu) fed physiologically relevant dosages of I3C (0.1 and 1 µmoles I3C/ g AIN-93 diet). Tumor analysis revealed a 49.7% decrease in tumor volume within the groups fed 0.1 and 1 µmoles I3C/g diet. Alterations in gene expression were assessed in tumor and liver samples. Consistent with previous results, treatment with I3C significantly upregulated Phase 1 xenobiotic metabolizing enzymes in liver. Moreover, reduced expression of integrin genes was observed in mice fed 1 µmole I3C/ g. However, we did not observe changes in CCL2 chemokine or macrophage markers. Results from this study indicate that I3C may reduce the likelihood of prostate cancer development by stimulating xenobiotic metabolism and modulating tumor adhesion properties. For Hypothesis 1.3, we evaluated the soy-derived phytochemicals glyceollins’ effect on reducing prostate cancer tumor growth in a xenograft model. Androgen responsive LNCaP cell and androgen independent PC-3 cell were used to establish cancer cell tumor xenograft in animals fed control or glyceollins supplemented diets. An initial delayed appearance of tumors was observed in PC-3 xenograft model; however, no difference in tumor sizes was observed in LNCaP xenograft. Statistical model analysis of tumor measurements indicated that no difference in sizes between animals fed control or glyceollins diet is expected for both PC-3 and LNCaP tumors at 100 days after injection. Glyceollins showed no effect on androgen responsiveness, proliferation, cell cycle, and angiogenesis genes in tumor and xenobiotic metabolism, cholesterol transport, and inflammatory cytokine genes in liver. Glyceollins’ low bioavailability (0.054 ± 0.013 µM) might have led to the ineffectiveness in reducing tumor growth in-vivo. Progress for Objective 2 is as follows. The effect of feeding probiotic Bifidobacterium lactis (Bb12) to swine sows during gestation and piglets during lactation on the composition of the intestinal microbiota was measured in juvenile pigs after feeding an obesogenic High fat (HF) diet. The HF diet increased intestinal bacteria within the phylum Firmicutes including species from Lactobacillaceae, Clostridiaceae 1 and Ruminococcaceae families, while the HF diet + Bb12increased Bacteroidaceae, Prevotellaceae and Porphyromonadaceae bacterial families within the phylum Bacteroidetes. Thus, dietary supplementation with Bb12 early in life induced a differential microbiome profile in pigs that is representative of enhanced intestinal health. Analysis is currently in progress to identify diet- and probiotic-induced responsive genes associated with inflammatory markers and microbiota taxa. 8040-51530-056-08H: Effect of Lowering Cholesterol on Markers of Cardiovascular Disease in Pigs Fed Atherogenic and Heart-Healthy Diets, TUFTS UNIVERSITY. Progress Report: Pigs fed a “heart healthy” diet had an improved serum lipid profile and reduced inflammatory markers. Ossabaw pigs fed a westernized diet high in saturated fat, cholesterol and refined grain manifested a dyslipedimc and inflammatory profile compared to pigs fed a heart-healthy diet high in unsaturated fats, whole grains and fruits and vegetables. Bacterial diversity in the intestine was not measurably increased but some changes in bacterial taxa abundances at bacterial family level were detected. Pigs fed the heart healthy diets showed an increase in Clostridiales (families Lachnospiraceae and Ruminococcaceae), indicative of intestinal health, that was reduced in pigs fed the Westernized diet. Feeding the heart healthy diet reduced liver metabolites such as D-erythro-sphingosine, cholesterol, and myristic acid at least 1.5-fold compared to pigs fed the westernized diet. Changes in the intestinal microbiome, transcriptome and metabolome are currently being analyzed. 8040-51530-056-16R: Prebiotic Effect of Dietary Agaricus Bisporus Mushroom on Intestinal Microbiota Composition and Host Immunological Function, MUSHROOM COUNCIL UNITED STATES. Progress Report: Edible mushrooms have been suggested to act as prebiotics that improve health. A study was designed in pigs to determine if feeding mushrooms enhanced immunity and a more diverse intestinal microbiota that could represent improved health in humans fed mushrooms. The consumption of 3 or 6 servings of mushroom significantly reduced pro-inflammatory gene expression in cells isolated from the lungs of pis. Analysis of bacterial genes in fecal samples indicated a positive shift in Firmicutes, particularly families within order Clostridiales that increase useful carbohydrate metabolism and biosynthesis of secondary metabolites. Thus, consumption of mushroom altered the composition of the host intestinal microbiota that increased carbohydrate metabolism and modulated host immunity by reducing inflammatory gene expression to promote health.
1. Plant microRNA bioavailability from diet. Dietary microRNA in plant-derived food has been proposed to be novel bioactive components that affect human health. Data on the accurate detection and quantification of food-derived microRNA’s after digestion and their uptake into plasma and tissues remain scarce. ARS scientists at Beltsville, Maryland, in collaboration with University of Maryland scientists and scientists at the NIH, developed a method that allows for accurate quantification of microRNA in plant and animal tissues. The method was used to elucidate the bioavailability of corn microRNA, and lead to the first report of extensive degradation of corn microRNA occurred during digestion and minimal amount was bioavailable.
2. Novel regulation of chemokine pathway in immune cells. Monocytes and macrophages are immune cells attracted by tumor cells to the tumor microenvironment and are often used as a marker to assess tumor development. Chemokine pathways regulate this process but the mechanisms remain unclear. ARS scientists at Beltsville, Maryland, in collaboration with University of Maryland scientists, examined the regulation of CXCR chemokine pathways. It was demonstrated that a transcriptional and translational disconnect exists and may influence the assessment of tumor outcomes when using the message or proteins from these pathways as surrogate biomarkers of tumor development and progression.
3. Pig model to simulate human dietary patterns developed. Good animal models for elucidating the role of diet on human health remain a challenge. ARS scientists at Beltsville, Maryland, in collaboration with Tufts University scientists examined effects of two human dietary patterns: Western Diet (WD, high in saturated fat, cholesterol, refined grains) and Heart Healthy Diet (HHD, high in unsaturated fat, whole grain, fruits/vegetables) on atorvastatin (Statin) therapy using Ossabaw pigs. Pigs fed the WD developed early atherosclerotic lesions in the heart, along with greater lipid deposition. Modest improvements in cardiometabolic risk factors and a lower degree of lesion formation was observed in pigs fed the WD+Statin. Ossabaw pigs manifested an altered lipid profile accompanied by early stage atherosclerosis when fed a WD, but not a Heart Healthy Diet. This pig model presents a new approach to examining the mechanistic pathways involved in diet-drug interactions and resulting effects on the development of atherosclerosis.
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Matthan, N.R., Solano Aguilar, G., Meng, H., Lamon-Fava, S., Goldbaum, A., Walker, M.E., Jang, S., Lakshman, S., Molokin, A., Xie, Y., Beshah, E., Stanley, J., Urban Jr, J.F., Lichtenstein, A.H. 2018. The Ossabaw pig is a suitable translational model to evaluate dietary patterns and coronary artery disease risk. Journal of Nutrition. 148(4):542-552. https://doi.org/10.1093/jn/nxy002.
Solano Aguilar, G., Lakshman, S., Jang, S., Beshah, E., Xie, Y., Sikaroodi, M., Gupta, R., Vinyard, B.T., Molokin, A., Urban Jr, J.F., Gillevet, P., Davis, C. 2018. The effect of feeding cocoa powder and Lactobacillus rhamnosus LGG on the composition and function of the intestinal microbiome. Current Developments in Nutrition. (2)5. https://doi.org/10.1093/cdn/nzy011.
Coleman, M., Elkins, C.A., Gutting, B.W., Mongodin, E.F., Solano Aguilar, G., Walls, I. 2018. Microbiota and dose-response: evolving paradigm of health triangle. Risk Analysis. 10.1111. https://doi.org/10.1111/risa.13121.
Jang, S., Lakshman, S., Beshah, E., Xie, Yue, Molokin, A., Vinyard, B.T., Urban Jr, J.F., Davis, C., Solano Aguilar, G. 2017. Lactobacillus rhamnosus LGG and flavanol-enriched cocoa powder altered the immune response to infection with the parasitic nematode Ascaris suum. Nutrients. pii: 1113. https://doi.org/10.3390/nu9101113.
Shay, A.E., Tukaramrao, D.B., Guan, B., Narayan, V., Urban Jr, J.F., Prabhu, S.K. 2017. Il-4 up-regulates cyclooxygenase-1 expression in macrophages. Journal of Biological Chemistry. 292(35):14544-14555. https://doi.org/10.1074/jbc.M117.785014.