title: Expression and function of NIK- and IKK2-binding protein (NIBP) in mouse enteric nervous system.
abstract: BACKGROUND
  NIK- and IKK2-binding protein (NIBP)/TRAPPC9 is expressed in brain neurons, and human NIBP mutations are associated with neurodevelopmental disorders. The cellular distribution and function of NIBP in the enteric nervous system (ENS) remain unknown.
  
  
  METHODS
  Western blot and reverse transcription-polymerase chain reaction analysis were used respectively to identify the protein and mRNA expression of NIBP and other neuronal markers. Multi-labeled immunofluorescent microscopy and confocal image analysis were used to examine the cellular distribution of NIBP-like immunoreactivity (IR) in whole mount intestine. Enteric neuronal cell line (ENC) was infected with lentivirus carrying NIBP or its shRNA expression vectors and treated with vehicle or tumor necrosis factor (TNF)α.
  
  
  RESULTS
  NIBP is expressed at both mRNA and protein levels in different regions and layers of the mouse intestine. NIBP-like-IR was co-localized with various neuronal markers, but not with glial, smooth muscular, or interstitial cells of Cajal markers. A small population of NIBP-expressing cells and fibers in extra-ganglionic and intra-ganglionic area were negative for pan-neuronal markers HuD or Peripherin. Relatively high NIBP-like-IR was found in 35-44% of myenteric neurons and 9-10% of submucosal neurons. Approximately 98%, 87%, and 43% of these relatively high NIBP-expressing neurons were positive for choline acetyltransferase, neuronal nitric oxide synthase and Calretinin, respectively. NIBP shRNA knockdown in ENC inhibited TNFα-induced NFκB activation and neuronal differentiation, whereas NIBP overexpression promoted it.
  
  
  CONCLUSIONS
  NIBP is extensively expressed in the ENS with relatively high level in a subpopulation of enteric neurons. Various NIBP expression levels in different neurons may represent dynamic trafficking or posttranslational modification of NIBP in some functionally active neurons and ultimately regulate ENS plasticity.
authors.affiliation: Department of Neuroscience, Temple University School of Medicine, Philadelphia, PA, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: D
authors.initials: D
authors.lastname: Bitner
authors.forename: A A
authors.initials: AA
authors.lastname: Pontes Filho
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: F
authors.initials: F
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Adhikari
authors.forename: J
authors.initials: J
authors.lastname: Gordon
authors.forename: S
authors.initials: S
authors.lastname: Srinivasan
authors.forename: W
authors.initials: W
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002461:Cell Line, Transformed; D017615:Enteric Nervous System / Q000166:cytology* / Q000378:metabolism*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000096:biosynthesis / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000502:physiology; D000097782:NF-kappaB-Inducing Kinase
chemical_list: D002352:Carrier Proteins; D051550:I-kappa B Kinase; D036341:Intercellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; D000097782:NF-kappaB-Inducing Kinase; C503887:TRAPPC9 protein, human; C496562:Ikbkb protein, mouse
keywords: NFκB; TRAPPC9/NIBP; confocal image; cytokines; enteric nervous system; enteric neuronal cell line; immunohistochemistry