Location: Diet, Genomics and Immunology Laboratory2009 Annual Report
1a. Objectives (from AD-416)
The overall goal of the project is to elucidate the molecular and cellular mechanisms that respond to selected health promoting food components to reduce the risk of chronic diseases such as cancers and obesity. A secondary aim is to explore the utility of a porcine model to test the effect of health maintenance via diet and identify resulting biomarkers that reflect health status. Objective 1. Elucidate biological activities of health promoting phytochemicals from grape, soy, and cruciferous vegetables against development of breast and prostate cancer. Objective 2. Identify molecular targets and mechanisms of action of health promoting food components in animal or in vitro models of cancer and obesity. Objective 3. Ascertain the effects of specific probiotic strains in appropriate animal models of obesity. Objective 4. Identify plant polyphenols and probiotics that affect adipocyte numbers, size, and fat accumulation, and the regulation of proinflammatory mRNA stability by tristetraprolin. Objective 5. Tie together obesity, inflammation, and cancer mechanistically in appropriate animal or in vitro models.
1b. Approach (from AD-416)
Studies will evaluate if phytoalexins structurally similar to resveratrol exerts similar anti-prostate cancer effects; if soy phytoalexin glyceollins exert anti-prostate cancer effects; if phytochemicals modulate LXR-mediated pathways in prostate epithelial cells and modulate LXR-mediated pathways in macrophage. Other studies will determine if probiotic bacterial strains differ in their protective effects against chronic diseases related to obesity; regulate adipocyte numbers, size, and fat accumulation associated with the anti-inflammatory protein tristetraprolin (TTP); if obesity alters the macrophage phenotype and function in adipose tissue, colon, breast, and prostate following increased localized inflammation; and if broccoli-derived phytochemicals modulate LXR-responsive pathways in vivo. The studies will involve in vitro cell culture approaches confirmed by rodent and pig animal models.
3. Progress Report
Notice was received in April 2009 that this project was approved and thus was in place for about five months during FY2009. We continue to examine the molecular action of phytochemicals on regulation of human sex hormone receptors, estrogen receptors (ERs), and androgen receptor (AR)-mediated events, which play important roles in breast and prostate cancer development. Sex hormone receptors can influence a cellular process such as cell death or apoptosis of breast cancer cells and this process can be modulated by soy-derived phytochemicals. We demonstrated that broccoli-derived phytochemicals can exert their cancer cell-growth inhibitory effects through regulation of ER expression. This is now being extended to evaluating the effects of compounds with structural similarity to reserveratrol, a phytoalexin found in grapes and other plants, to evluate the effect on AR-mediated gene expression. Both T regulatory cells and the alternatively activated macrophage are important cells regulating responses to chronic disease. The current project plan will characterize the role of these cells at the molecular, cellular, and whole animal level in response to a high fat, high cholesterol, high refined carbohydrate diet used to induce metabolic syndrome in Ossabaw pigs and in adipose tissue and isolated stromal cells. Probiotic bacteria have beneficial effects on intestinal immune and mucosal barrier function; probiotic (Bifidobacterium lactis)-treated pigs show changes in gene expression of immune mediators indicating local activation of the innate immune system at the intestinal mucosa and induction of changes that improve intestinal permeability, a response enhanced in probiotic-treated pigs from probiotic-treated mothers. Probiotics in the diet also modulate inflammatory responses against intestinal parasites and bovine milk used as a food allergen. This research promotes the concept that probiotics in the diet differentially affect immune components associated with resolution of infectious and chronic disease. Treating juvenile Ossabaw pigs with probiotics is a logical extension of earlier studies on parasite and allergen-induced inflammation in conventional pigs.