Project Number: 6250-51000-054-02
Project Type: Specific Cooperative Agreement

Start Date: Oct 01, 2005
End Date: Sep 30, 2010

Objective:
The objective of this cooperative research is to establish the role of critical nutritional, endocrine and genetic factors on growth, development and function of mammalian cells, tissues, and organs. 1) Intestinal Amino Acid Requirements in Neonates - Determine metabolic fate and regulatory role of essential amino acids, especially methionine and cysteine, in intestinal epithelial cells in neonates. 2) Nutritional Regulation of Tissue Anabolism in Neonates - Determine the regulatory role of branched-chain amino acids, especially leucine, and glucose on activation of cellular protein synthesis signaling mechanisms in neonates. 3) Nutrient Regulation of Blood and Blood Vessel Formation - Determine the molecular function of vitamin A in vascular development and embryonic hematopoiesis and the key signaling molecules involved. 4) Consequences of Perinatal Undernutrition for Satellite Cell Function and Skeletal Muscle Growth - Determine how maternal gestational malnutrition affects glucocorticoid status, growth factor expression and satellite cell proliferation in skeletal muscle and whether these factors contribute to postnatal growth impairment of offspring. 5) Nutritional Influence on Gastrointestinal Function - Determine the impact of glutamine, simple sugars, soluble fiber, and probiotics on intestinal sensory, motor and immune function in infants and children. 6) Physiological Role of Obestatin Receptor in Control of Energy Homeostasis and Obesity Development - Understand the role of obestatin and GPR39 gene receptor which will increase our knowledge about critical development of obesity and type II diabetes in human.

Approach:
1) Intestinal Amino Acid Requirements in Neonates - Quantify the metabolism of isotopic-labeled sulfur amino acids when given enterally and parenterally to neonatal piglets in vivo and in cultured intestinal epithelial cells in vitro. The in vivo rates and cellular localization of sulfur amino acid metabolism via transmethylation into homocysteine, transsulfuration into cysteine and incorporation into glutathione will be quantified. 2) Nutritional Regulation of Tissue Anabolism in Neonates - The fractional rates of tissue protein synthesis and the activation and/or protein-protein interaction of nutrient signaling proteins will be determined in tissues from neonatal piglets infused with amino acids and glucose to achieve levels within the fasting to fed range. Modulators of cellular nutrient signaling (rapamycin, LY294002 and AICAR) will be infused to distinguish the specificity of key signaling pathways. 3) Nutrient Regulation of Blood and Blood Vessel Formation - Endodermal differentiation and subsequent induction of endothelial cell growth, maturation, and vessel assembly will be characterized in retinoic acid deficient embryos cultured in the presence and absence of endodermally derived signals. 4) Consequences of Perinatal Undernutrition for Satellite Cell Function and Skeletal Muscle Growth - The production of hematopoietic cells from mesodermal progenitors and the expression of specific target genes will be measured in normal and mutant cultured embryos in response to retinoic acid sufficiency and deficiency. Protein synthesis, growth factor expression, satellite cell cycle activity, rDNA transcription, and rRNA abundance will be measured in skeletal muscle of offspring from dams subjected to manipulation of nutrition and glucocorticoid status during gestation. 5) Nutritional Influence on Gastrointestinal Function - Bowel motor and sensory patterns, stool transit time, permeability, and fecal calprotectin will be measured in children randomized and stratified by age to receive in a double blind fashion either fiber psyllium, probiotic, or glucose for four weeks. Children with bowel pain that do not respond to treatment will be placed on a lactose, sorbitol, fructose restricted diet and reassessed for intestinal functional endpoints. Infection rate and duration of hospitalization will be measured in preterm infants fed glutamine-supplemented or placebo formulas. 6) Physiological Role of Obestatin Receptor in Control of Energy Homeostasis and Obesity Development - Implement a series of experiments utilizing the mouse model and analysis of the hypothalamus in order to understand GPR39 gene function.