title: Probiotics promote endocytic allergen degradation in gut epithelial cells.
abstract: OBJECTIVE
  Epithelial barrier dysfunction plays a critical role in the pathogenesis of allergic diseases; the mechanism is to be further understood. The ubiquitin E3 ligase A20 (A20) plays a role in the endocytic protein degradation in the cells. This study aims to elucidate the role of A20 in the maintenance of gut epithelial barrier function.
  
  
  METHODS
  Gut epithelial cell line, HT-29 cell, was cultured into monolayers to evaluate the barrier function in transwells. RNA interference was employed to knock down the A20 gene in HT-29 cells to test the role of A20 in the maintenance of epithelial barrier function. Probiotic derived proteins were extracted from the culture supernatants using to enhance the expression of A20 in HT-29 cells.
  
  
  RESULTS
  The results showed that the knockdown of A20 compromised the epithelial barrier function in HT-29 monolayers, mainly increased the intracellular permeability. The fusion of endosome/lysosome was disturbed in the A20-deficient HT-29 cells. Allergens collected from the transwell basal chambers of A20-deficient HT-29 monolayers still conserved functional antigenicity. Treating with probiotic derived proteins increased the expression of A20 in HT-29 cells and promote the barrier function.
  
  
  CONCLUSIONS
  A20 plays an important role in the maintenance of epithelial barrier function as shown by HT-29 monolayer. Probiotic derived protein increases the expression of A20 and promote the HT-29 monolayer barrier function.
authors.affiliation: Department of Epidemiology & Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou, China.
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Song
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Shelly
authors.initials: S
authors.lastname: Huang
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Zheng
authors.forename: Ping-Chang
authors.initials: PC
authors.lastname: Yang
mesh_terms: D055516:2S Albumins, Plant / Q000378:metabolism; D000485:Allergens / Q000378:metabolism*; D052179:Antigens, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D004847:Epithelial Cells / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D019936:Probiotics / Q000378:metabolism*; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3
chemical_list: D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D004268:DNA-Binding Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3