title: Glutamine enhances tight junction protein expression and modulates corticotropin-releasing factor signaling in the jejunum of weanling piglets.
abstract: BACKGROUND
  Dysfunction of tight junction integrity is associated with decreased nutrient absorption and numerous gastrointestinal diseases in humans and piglets. Although l-glutamine has been reported to enhance intestinal-mucosal mass and barrier function under stressful conditions, in vivo data to support a functional role for l-glutamine on intestinal tight junction protein (TJP) expression in weanling mammals are limited.
  
  
  OBJECTIVE
  This study tested the hypothesis that glutamine regulates expression of TJPs and stress-related corticotropin-releasing factor (CRF) signaling in the jejunum of weanling piglets.
  
  
  METHODS
  Piglets were reared by sows or weaned at 21 d of age to a corn and soybean meal-based diet that was or was not supplemented with 1% l-glutamine for 7 d. Growth performance, intestinal permeability, TJP abundance, and CRF expression were examined.
  
  
  RESULTS
  Weaning caused increases (P < 0.05) in intestinal permeability by 40% and in CRF concentrations by 4.7 times in association with villus atrophy (P < 0.05). Western blot analysis showed reductions (P < 0.05) in jejunal expression of occludin, claudin-1, zonula occludens (ZO) 2, and ZO-3, but no changes in the abundance of claudin-3, claudin-4, or ZO-1 in weanling piglets compared with age-matched suckling controls. Glutamine supplementation improved (P < 0.05) intestinal permeability and villus height, while reducing (P < 0.05) jejunal mRNA and protein levels for CRF and attenuating (P < 0.05) weanling-induced decreases in occludin, claudin-1, ZO-2, and ZO-3 protein abundances.
  
  
  CONCLUSIONS
  Collectively, our results support an important role for l-glutamine in regulating expression of TJPs and CRF in the jejunum of weanling piglets.
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and Department of Animal Science, Texas A&M University, College Station, TX.
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Yuli
authors.initials: Y
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Beibei
authors.initials: B
authors.lastname: He
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and.
authors.forename: Zhaolai
authors.initials: Z
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; and bio2046@hotmail.com.
authors.forename: Zhenlong
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000818:Animals; D057167:Claudins / Q000032:analysis; D003346:Corticotropin-Releasing Hormone / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D019587:Dietary Supplements; D015870:Gene Expression / Q000187:drug effects; D005973:Glutamine / Q000008:administration & dosage*; D007408:Intestinal Absorption / Q000187:drug effects; D007583:Jejunum / Q000033:anatomy & histology / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D034421:Sus scrofa; D062725:Tight Junction Proteins / Q000032:analysis*; D014886:Weaning; D062825:Zonula Occludens Proteins / Q000032:analysis
chemical_list: D057167:Claudins; D062725:Tight Junction Proteins; D062825:Zonula Occludens Proteins; D005973:Glutamine; D003346:Corticotropin-Releasing Hormone
keywords: corticotropin-releasing factor; glutamine; pigs; small intestine; tight junction; weaning stress