2011 Annual Report
1a.Objectives (from AD-416)
LAB: NUTRITIONAL IMMUNOLOGY
1. Determine the effect and mechanisms of food components and their interaction with age on immune function and infectious diseases.
a) Determine the mechanisms of Vitamin E-induced enhancement of T cell function in the aged with focus on early activation signaling and membrane related events.
b) Determine the contribution of polymorphisms at cytokine genes to heterogeneity of vitamin E-induced effects on cytokine production and resistance to respiratory infections.
2. Determine the effect of reducing caloric intake on the immune response of humans.
3. Determine the effect and mechanisms of food components and their interaction with age on immune function and infectious diseases.
LAB: VASCULAR BIOLOGY
1. Identify bioactive food components and food patterns that inhibit atherosclerosis and angiogenesis using cell culture, animal models and human subjects under the following sub-objectives:
a) Determine bioavailability of avenanthramides from oats and characterize their potency and molecular mechanism of inhibition of vascular smooth muscle cell proliferation using cell culture systems and the femoral artery injury mouse model.
b) Elucidate the molecular mechanism of catechins and curcumin and other dietary bioactive compounds on the inhibition of angiogenesis associated with adipose tissue growth and obesity.
c) Determine the comparative bioavailability and biopotency of tocopherols versus tocopheryl phosphate on the inhibition of femoral artery injury model of vascular atherosclerosis and restenosis.
2. Determine the anti-inflammatory and anti-proliferative effects of avenanthramides of oats and derivatives on several colonic cancer cells lines and mouse models of inflammatory bowel disease and colon cancer.
1b.Approach (from AD-416)
LAB: NUTRITIONAL IMMUNOLOGY
T cell function declines with age resulting in higher incidence of infections in the elderly. We showed that vitamin E (E) supplementation enhances T cell function in the aged. In Objective 1-A, we will test the hypothesis that T cell receptor (TCR)-induced signalosomes (combination of protein and lipids that are formed at the site of T cell and antigen presenting cells) exhibit age- and vitamin E (E)-related differences in their patterns of protein and lipid recruitment. We will identify qualitative and quantitative age- and E-related differences in the protein and lipid composition of signalosomes using an enhanced magnetic immunoisolation procedure and highly sensitive and quantitative proteomics and lipidomics methods. In objective 1-B, we will test the hypothesis that higher frequencies of specific cytokine polymorphisms contribute to incidence and severity of respiratory infection (RI) in the aged and that the effect of E on RI is dependent on cytokine genotype. This will be tested using data and DNA samples collected from a 1-year randomized, double-blind, controlled (RTC) study of E supplementation in elderly. In Objective 2 we will test the hypothesis that a long- term calorie restriction (CR) intervention in humans will enhance T cell-mediated function and that the CR- mediated effect is due to intrinsic changes in T cells and/or a reduction in prostaglandin PGE2 production. This hypothesis will be tested utilizing subjects enrolled in the NIA- supported multi-center RTC, CALERIE Phase 2 and determining the effect of CR on T cell subsets proliferation, and intra- and extra-cellular cytokine, and PGE2 levels before, and following 1 and 2 years of 25% CR. These studies will help develop effective strategies to improve the immune response in the elderly.
LAB: VASCULAR BIOLOGY
The main objective of this project plan is to determine bioavailability, potency and mechanism of action of several bioactive food components, including avenanthramides (Avns) of oats, curcumin of turmeric, catechins of green tea and isomers of tocopherol in the prevention of atherosclerosis and angiogenesis as they relate to CVD, obesity and cancer. Specifically, we will determine bioavailability of Avns from oats and characterize their potency and mechanism of inhibition of vascular smooth muscle cell proliferation using cell culture and the femoral artery injury mouse model. Further, we will investigate the anti-inflammatory and anti-proliferative effects of Avns of oats and derivatives on several cancer cells lines and mouse models of inflammatory bowel disease and colon cancer. We will also elucidate the molecular mechanism of catechins and curcumin and other dietary bioactive compounds on the inhibition of angiogenesis associated with adiposity and obesity. We also plan to investigate the comparative biopotency of' alpha-tocopherol (alpha-T) versus alpha-tocopheryl phosphate (alpha-TP) on the inhibition inflammatory cytokines and monocyte adhesion in cell culture systems and on comparative bioavailability and efficacy of alpha-T vs. alpha-TP on femoral artery injury model of atherosclerosis.
This progress report includes the work of two subordinate projects at the HNRCA funded through a Specific Cooperative Agreement with TUFTS UNIVERSITY. For further information and progress reports, see 1950-51000-068-01S (Nutrition, Aging, Immune and Inflammatory Responses in health and Diseases) and 1950-51000-068-02S (Bioactive Food components and Modulation of Atherosclerosis and Angiogenesis).
LAB: Vascular Biology Curcumin, bioactive component of turmeric spice inhibits obesity and atherogenesis. Obesity and associated disorders including cardiovascular disease (CVD) are prevalent in US. ARS-funded researchers at JMUSDA-HNRCA at Tufts University, Boston, MA, continued further investigation of curcumin, the bioactive component of turmeric spice for its biological activity within the context of, obesity, atherosclerosis and angiogenesis. They demonstrated, in an animal model fed high fat diet, that curcumin can prevent body weight gain, adiposity, atherosclerosis, and fatty liver formation. They further showed that curcumin exerts this effect through several mechanisms, including; up-regulating basal metabolism and burning body fat, and by suppressing growth of new blood vessels (angiogenesis) in fat tissue, which is needed for fat tissue growth and expansion. In addition, curcumin may prevent development of CVD by suppressing atherogenesis as observed in mouse model of human atherosclerosis. They have elucidated these important health effects of curcumin on obesity and CVD by investigating its mechanisms of effect at cellular and molecular levels. These findings provide a platform to translate their findings to humans.
Natural vitamin E analogue, alpha-tocopheryl phosphate (alpha-TP), modulates inflammation associated with atherosclerosis more efficiently than alpha-tocopherol (alpha-T). ARS-funded researchers at JMUSDA-HNRCA at Tufts University, Boston, MA, showed that alpha-TP, a natural bioactive form of vitamin E (alpha-Tocopherol) modulates inflammatory processes associated with atherosclerosis more efficiently than alpha-T through non-antioxidant activity. Alpha-TP may bind to a cell surface receptor (CD36) and/or trigger its internalization, resulting its inactivation. Their gene array analysis showed that alpha-TP stimulate production of protein called vascular endothelial growth factor that stimulate formation of new blood vessels (angiogenesis), which may promote wound healing and blood perfusion following ischemia. Their observations have indicated that increasing alpha-TP status, the natural bioactive analogue of vitamin E may be beneficial for promotion of health where inflammation and angiogenesis are the major players.
LAB: Nutritional Immunology Green tea active component alleviates autoimmune disorders. Incidence of autoimmune diseases increases with aging. Higher consumption of green tea and its component Epigallocatechin (EGCG) have been shown to affect the function of immune cells that are involved in the development or pathogenesis of autoimmune diseases. ARS-funded researchers at JMUSDA-HNRCA at Tufts University, Boston, MA, conducted a study to determine the impact of increasing consumption of EGCG on pathogenesis of autoimmune diseases using different doses of EGCG on an animal model for a human autoimmune disease, multiple sclerosis. We found that giving mice EGCG in amounts equivalent to that found in 10 cups of green tea or that in supplements resulted in prevention of clinical signs and symptoms of the disease. EGCG alleviated disease incidence and associated central nervous system symptoms (CNS) by inhibiting immune cell infiltration into CNS and by favorably modulating the balance among pro-and anti-autoimmune T cell subpopulations.The information obtained in this study not only identifies green tea as a nutritional strategy to reduce the symptoms of autoimmune diseases but also indicates potential targets to develop new preventative measures for these diseases in humans.
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