title: Wnt blockade with dickkopf reduces intestinal crypt fission and intestinal growth in infant rats.
abstract: OBJECTIVE
  Intestinal crypt fission peaks during infancy. In human and experimental familial polyposis coli, increased crypt fission is due to activation of Wnt/β-catenin signalling, but the molecular basis of crypt fission during intestinal growth has not been examined. The aim of this project was to investigate whether crypt fission and intestinal growth are affected by experimental blockade of the Wnt/β-catenin signalling pathway.
  
  
  METHODS
  Hooded Wistar rats were given either the Wnt inhibitor, dickkopf (30 and 100 ng), daily or vehicle control intraperitoneally from days 11 to 15 and were killed at day 16. Intestinal morphometry was used to measure villous area, crypt area, percentage of crypt fission, and crypt mitotic count. Intestinal stem cells were assessed by expression of real time-polymerase chain reaction for Lgr5 (a stem cell marker), and the number of β-catenin-expressing crypts by immunostaining was determined after 100-ng dickkopf treatment.
  
  
  RESULTS
  Dickkopf at 30 and 100 ng/day reduced villous area to 71% (P = 0.013) and 29% (P < 0.0001), crypt area to 42% (P = 0.0026) and 30% (P = 0.0067), and crypt fission to 51% (P = 0.006) and 29% (P < 0.0001), respectively, of control values. Mitotic count per crypt did not change. Lgr5 RNA expression and the number of β-catenin-expressing crypts decreased in dickkopf-treated animals.
  
  
  CONCLUSIONS
  We conclude that intestinal crypt fission during infancy is mediated by Wnt signalling. It is possible that local treatment with Wnt agonists could be used to increase intestinal growth.
authors.affiliation: School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, South Australia, Australia. jane.fauser@adelaide.edu.au
authors.forename: Jane K
authors.initials: JK
authors.lastname: Fauser
authors.forename: Rino P
authors.initials: RP
authors.lastname: Donato
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Woenig
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Proctor
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Trotta
authors.forename: Phulwinder K
authors.initials: PK
authors.lastname: Grover
authors.forename: Gordon S
authors.initials: GS
authors.lastname: Howarth
authors.forename: Irmeli A
authors.initials: IA
authors.lastname: Penttila
authors.forename: Adrian G
authors.initials: AG
authors.lastname: Cummins
mesh_terms: D000818:Animals; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects* / Q000473:pathology; D008940:Mitotic Index; D063150:Polycomb Repressive Complex 1 / Q000187:drug effects / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D051176:beta Catenin / Q000187:drug effects / Q000378:metabolism*
chemical_list: C489420:Bmi1 protein, rat; C531384:Dkk1 protein, rat; D036341:Intercellular Signaling Peptides and Proteins; C576179:Lgr5 protein, rat; D043562:Receptors, G-Protein-Coupled; D051176:beta Catenin; D012313:RNA; D063150:Polycomb Repressive Complex 1