Rho-kinase expression in Hirschsprung's disease.
BACKGROUND
Rho-kinase (ROCK) is the primary effector protein in the RhoA pathway, which regulates Ca(2+)-independent smooth muscle contraction in the human bowel. This pathway has been reported to be hyper-activated in the aganglionic bowel of EDNRB-null (-/-) rats compared to the ganglionic bowel from EDNRB (+/+) rats. We hypothesised that ROCK expression is up-regulated in human aganglionic bowel and designed this study to investigate ROCK 1 and ROCK 2 expression in Hirschsprung's disease (HSCR) and controls.


METHODS
Full-length specimens were collected following pull-through surgery for HSCR (n = 9). Colonic controls (n = 6) were obtained during colostomy closure from patients with anorectal malformations. Distribution of ROCK 1/2 expression was evaluated using double-labelled immunofluorescence and confocal microscopy. ROCK1/2 protein expression was assessed in mucosa and tunica muscularis using western blot analysis.


RESULTS
There was strong expression of both ROCK 1 and ROCK 2 in interstitial cells of Cajal (ICCs) and ganglia. ROCK 1 expression was reduced in aganglionic bowel compared to HSCR ganglionic bowel and controls in both mucosa and tunica muscularis. ROCK 2 expression was similar in the colon of children with HSCR and controls.


CONCLUSIONS
This is the first report of strong ROCK expression in colonic ICCs. Although the rat model of aganglionic bowel suggests that Ca(2+)-independent smooth muscle contraction involving ROCK is hyper-activated, our data indicate ROCK 1 expression is decreased in aganglionic bowel and ROCK 2 expression is unaltered in children with HSCR.
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin Rd., Dublin 12, Ireland. daithiocool@gmail.com.|Department of Paediatric Surgery, Temple Street Children's University Hospital, Temple St., Dublin 1, Ireland. daithiocool@gmail.com.
David
http://orcid.org/0000-0002-7685-6417
D
Coyle
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin Rd., Dublin 12, Ireland.
Anne Marie
AM
O'Donnell
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin Rd., Dublin 12, Ireland.
Nicolae
N
Corcionivoschi
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin Rd., Dublin 12, Ireland.|Department of Paediatric Surgery, Temple Street Children's University Hospital, Temple St., Dublin 1, Ireland.
John
J
Gillick
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin Rd., Dublin 12, Ireland.
Prem
P
Puri
D015153:Blotting, Western; D005260:Female; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000235:genetics*; D006627:Hirschsprung Disease / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D054460:rho-Associated Kinases / Q000235:genetics*
D054460:rho-Associated Kinases
Aganglionosis; Colonic motility; Hirschsprung; Rho-kinase; Smooth muscle