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United States Department of Agriculture

Agricultural Research Service

Research Project: Molecular, Cellular, and Regulatory Aspects of Nutrition During Development

Location: Children's Nutrition Research Center

Project Number: 3092-51000-060-00
Project Type: Appropriated

Start Date: Mar 31, 2014
End Date: Mar 30, 2019

Objective:
The goal of this research is to identify strategies to optimize the nutrition and health of infants and their development. CNRC researchers will: 1) investigate the impact of perinatal nutrition in the model system of premature piglets on the prevention of parenteral nutrition-associated liver disease (PNALD) and necrotizing enterocolitis (NEC); 2) define the role of liver receptor homolog-1 (LRH-1) as a factor in hepatic lipotropic responses, including the influence of methionine/choline deficient diets (MCD); 3) characterize the effect of the loss of hepatic LRH-1 in the lipotropic response to methyl pool supplementation in the standard mouse model of diet induced obesity; 4) determine the influence of leucine supplementation in stimulating protein synthesis, enhancing lean growth, and reducing protein degradation in healthy neonatal piglets and during catabolic conditions such as sepsis; 5) determine whether the deficit in lean deposition incurred with continuous as compared to intermittent bolus feeding during the neonatal period can be prevented by leucine supplementation or recuperated by initiation of intermittent bolus feeding; 6) determine whether citrulline plasma concentration is an early indicator for gut immaturity and gut dysfunction in a piglet model of prematurity; 7) determine if arginine and citrulline supplementation are able to reduce the incidence of necrotizing enterocolitis; 8) identify the cellular signaling networks that modify leptin-signal transducer and activator of transcription 3 (STAT3) signaling and potentially contribute to leptin resistance; 9) determine, using genetically engineered mouse models, the role of a cellular leptin signaling modifier in high fat diet-induced leptin resistance and subsequent alterations in energy and glucose homeostasis, and adiposity; 10) study the mechanism of circadian dysfunction-induced leptin resistance and the role of leptin resistance in obesity development; 11) determine the contributions of alpha Beta and yoT cells to inflammation in skeletal muscle; 12) determine the mechanisms leading to early anti-inflammatory macrophage polarization in mesenteric adipose tissue and the peritoneal cavity of C57BL/6J mice; 13) define how tissue healing is dysregulated in Western-style diet-induced obesity; 14) determine if Matrix Metalloproteinase 12 influences the development of insulin resistance and tissue inflammation in the context of high fat, Western-type diet-induced obesity; 15) determine if Matrix Metalloproteinase 12 influences white adipose tissue extracellular matrix remodeling under conditions of Western-type diet feeding.

Approach:
The research will be accomplished using a variety of models and scientific tools to simulate the human newborn and/or child. Researchers will perform tissue transcriptomic profiling to identify novel genes, gene networks and metabolic pathways that are differentially affected by two lipid emulsions. We will also quantify expression of targeted genes involved in hepatic bile acid metabolism. In mouse models, physiologic studies will be performed that will include analysis of serum and hepatic levels of trigylcerides, free fatty acids, total cholesterol and total phosphatidylcholine. Using porcine models, we will perform protein synthesis experiments in leucine-infused endotoxemic pigs. Additionally we will use porcine models to determine if arginine and citrulline supplementation reduces the incidence of necrotizing enterocolitis. CNRC researchers will also employ an ex vivo model to determine if STAT3 signaling acts as a signaling hub for distinct signaling pathways mediating cellular leptin resistance. Complicated studies will be performed to study the mechanism of reciprocal interactions between the central circadian clock and hypothalamic arcuate nucleus in maintaining homeostasis of leptin signaling. Researchers will also study the role of circadian dysfunction of sympathetic nervous system (SNS) signaling in the development of leptin resistance and diet-induced obesity. And finally scientists will use a murine model (that develops chronic inflammation similar to that observed in obese humans) of diet-induced obesity and will use short- and long-term feeding techniques for the localization and phenotypic characterization of lymphocytes in skeletal muscle, and techniques for depletion of lymphocyte subsets.

Last Modified: 11/25/2014
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