title: Canonical Wnt signals combined with suppressed TGFβ/BMP pathways promote renewal of the native human colonic epithelium.
abstract: BACKGROUND
  A defining characteristic of the human intestinal epithelium is that it is the most rapidly renewing tissue in the body. However, the processes underlying tissue renewal and the mechanisms that govern their coordination have proved difficult to study in the human gut.
  
  
  OBJECTIVE
  To investigate the regulation of stem cell-driven tissue renewal by canonical Wnt and TGFβ/bone morphogenetic protein (BMP) pathways in the native human colonic epithelium.
  
  
  METHODS
  Intact human colonic crypts were isolated from mucosal tissue samples and placed into 3D culture conditions optimised for steady-state tissue renewal. High affinity mRNA in situ hybridisation and immunohistochemistry were complemented by functional genomic and bioimaging techniques. The effects of signalling pathway modulators on the status of intestinal stem cell biology, crypt cell proliferation, migration, differentiation and shedding were determined.
  
  
  RESULTS
  Native human colonic crypts exhibited distinct activation profiles for canonical Wnt, TGFβ and BMP pathways. A population of intestinal LGR5/OLFM4-positive stem/progenitor cells were interspersed between goblet-like cells within the crypt-base. Exogenous and crypt cell-autonomous canonical Wnt signals supported homeostatic intestinal stem/progenitor cell proliferation and were antagonised by TGFβ or BMP pathway activation. Reduced Wnt stimulation impeded crypt cell proliferation, but crypt cell migration and shedding from the crypt surface were unaffected and resulted in diminished crypts.
  
  
  CONCLUSIONS
  Steady-state tissue renewal in the native human colonic epithelium is dependent on canonical Wnt signals combined with suppressed TGFβ/BMP pathways. Stem/progenitor cell proliferation is uncoupled from crypt cell migration and shedding, and is required to constantly replenish the crypt cell population.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, , Norwich, Norfolk, UK.
authors.forename: Amy
authors.initials: A
authors.lastname: Reynolds
authors.forename: Natalia
authors.initials: N
authors.lastname: Wharton
authors.forename: Alyson
authors.initials: A
authors.lastname: Parris
authors.forename: Esther
authors.initials: E
authors.lastname: Mitchell
authors.forename: Anastasia
authors.initials: A
authors.lastname: Sobolewski
authors.forename: Christy
authors.initials: C
authors.lastname: Kam
authors.forename: Loren
authors.initials: L
authors.lastname: Bigwood
authors.forename: Ahmed
authors.initials: A
authors.lastname: El Hadi
authors.forename: Andrea
authors.initials: A
authors.lastname: Münsterberg
authors.forename: Michael
authors.initials: M
authors.lastname: Lewis
authors.forename: Christopher
authors.initials: C
authors.lastname: Speakman
authors.forename: William
authors.initials: W
authors.lastname: Stebbings
authors.forename: Richard
authors.initials: R
authors.lastname: Wharton
authors.forename: Kevin
authors.initials: K
authors.lastname: Sargen
authors.forename: Richard
authors.initials: R
authors.lastname: Tighe
authors.forename: Crawford
authors.initials: C
authors.lastname: Jamieson
authors.forename: James
authors.initials: J
authors.lastname: Hernon
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kapur
authors.forename: Naohide
authors.initials: N
authors.lastname: Oue
authors.forename: Wataru
authors.initials: W
authors.lastname: Yasui
authors.forename: Mark R
authors.initials: MR
authors.lastname: Williams
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019485:Bone Morphogenetic Proteins / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D003106:Colon / Q000502:physiology*; D006801:Humans; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000502:physiology; D018613:Microscopy, Confocal; D008875:Middle Aged; D012038:Regeneration / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000502:physiology*; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta
keywords: Epithelial Differentiation; Epithelial Kinetics; Epithelial Proliferation; Imaging; Stem Cells