title: Lactobacillus rhamnosus GG supernatant upregulates serotonin transporter expression in intestinal epithelial cells and mice intestinal tissues.
abstract: BACKGROUND
  The role that probiotics play in relieving irritable bowel syndrome (IBS) has been demonstrated; however, the mechanism by which IBS is affected remains unclear. In this study, serotonin transporter (SERT) mRNA and serotonin transporter protein (SERT-P) levels in HT-29, Caco-2 cells, and mice intestinal tissues were examined after treatment with Lactobacillus rhamnosus GG supernatant (LGG-s).
  
  
  METHODS
  HT-29 and Caco-2 cells were treated with different concentrations of LGG-s for 12 and 24 h and C57BL/6 mice received supplements of different concentrations for 4 weeks. SERT mRNA and SERT-P levels were detected by real-time PCR and Western blotting.
  
  
  RESULTS
  SERT mRNA and SERT-P levels in HT-29 and Caco-2 cells were higher than those in the control 24 h after treatment. Undiluted LGG-s upregulated SERT mRNA levels by 9.4-fold in the first week, which dropped in the second week. The double-diluted LGG-s upregulated SERT mRNA by 2.07-fold in the first week; levels dropped to 1.75-fold within the second week and under base expression levels by the third week, while they again climbed to 1.56-fold in the fourth week. The triple-diluted LGG-s could not upregulate SERT mRNA expression until the end of the fourth week. The SERT-P levels in the double-diluted LGG-s group were higher than that in the control but fluctuated with time. SERT-P levels in the triple-diluted LGG-s were higher than that in the control in the last 2 weeks and increased with time.
  
  
  CONCLUSIONS
  LGG-s can upregulate SERT mRNA and SERT-P levels in intestinal epithelial cells and mice intestinal tissues.
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: X Z
authors.initials: XZ
authors.lastname: Ge
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: W Q
authors.initials: WQ
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: T
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: H L
authors.initials: HL
authors.lastname: Cao
authors.affiliation: Key Research Laboratory of Hormone and Development Affiliated to the Ministry of Health, Institute of Endocrinology, Tianjin Medical University, Tianjin, China.
authors.forename: B L
authors.initials: BL
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: B M
authors.initials: BM
authors.lastname: Wang
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D019073:HT29 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D052201:Lacticaseibacillus rhamnosus / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; C493231:Slc6a4 protein, mouse
keywords: Lactobacillus rhamnosus supernatant; SERT mRNA; SERT protein; intestinal tissues; serotonin transporter