title: Side-stream smoking reduces intestinal inflammation and increases expression of tight junction proteins.
abstract: OBJECTIVE
  To investigate the effect of side-stream smoking on gut microflora composition, intestinal inflammation and expression of tight junction proteins.
  
  
  METHODS
  C57BL/6 mice were exposed to side-stream cigarette smoking for one hour daily over eight weeks. Cecal contents were collected for microbial composition analysis. Large intestine was collected for immunoblotting and quantitative reverse transcriptase polymerase chain reaction analyses of the inflammatory pathway and tight junction proteins.
  
  
  RESULTS
  Side-stream smoking induced significant changes in the gut microbiota with increased mouse intestinal bacteria, Clostridium but decreased Fermicutes (Lactoccoci and Ruminococcus), Enterobacteriaceae family and Segmented filamentous baceteria compared to the control mice. Meanwhile, side-stream smoking inhibited the nuclear factor-κB pathway with reduced phosphorylation of p65 and IκBα, accompanied with unchanged mRNA expression of tumor necrosis factor-α or interleukin-6. The contents of tight junction proteins, claudin3 and ZO2 were up-regulated in the large intestine of mice exposed side-stream smoking. In addition, side-stream smoking increased c-Jun N-terminal kinase and p38 MAPK kinase signaling, while inhibiting AMP-activated protein kinase in the large intestine.
  
  
  CONCLUSIONS
  Side-stream smoking altered gut microflora composition and reduced the inflammatory response, which was associated with increased expression of tight junction proteins.
authors.affiliation: Department of Animal Science, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Jun-Xing
authors.initials: JX
authors.lastname: Zhao
authors.forename: Nan
authors.initials: N
authors.lastname: Hu
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
authors.forename: Min
authors.initials: M
authors.lastname: Du
authors.forename: Mei-Jun
authors.initials: MJ
authors.lastname: Zhu
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D062465:Claudin-3; D057167:Claudins / Q000235:genetics / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D005260:Female; D020672:I-kappa B Proteins / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000378:metabolism / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D007420:Intestine, Large / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D000072000:NF-KappaB Inhibitor alpha; D062793:Occludin; D018384:Oxidative Stress; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019108:Tight Junctions / Q000378:metabolism*; D014028:Tobacco Smoke Pollution; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D062465:Claudin-3; D057167:Claudins; C568123:Cldn3 protein, mouse; D020672:I-kappa B Proteins; D018836:Inflammation Mediators; D015850:Interleukin-6; D008565:Membrane Proteins; C000606205:Nfkbia protein, mouse; D062793:Occludin; C568986:Ocln protein, mouse; D010750:Phosphoproteins; D012333:RNA, Messenger; C498144:Rela protein, mouse; C569043:Tjp1 protein, mouse; C569047:Tjp2 protein, mouse; D014028:Tobacco Smoke Pollution; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein; D000072000:NF-KappaB Inhibitor alpha; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases