Down-Regulation of SHH/BMP4 Signalling in Human Anorectal Malformations

Abstract

The sonic hedgehog homologue (SHH)/bone morphogenetic protein 4 (BMP4) signalling pathway is involved in the morphogenesis of many organ systems. This study was designed to investigate the expression of SHH/BMP4 pathway components in human anorectal malformations (ARMs) and the relationship between expression of their genes and the occurrence of ARMs. Expression of SHH, GLI family zinc finger 2 (GLI2) and BMP4 mRNA in the posterior wall of the terminal rectum in 40 patients with ARMs (15 high-type and 25 low-type) and 10 normal controls was assessed by reverse transcription-polymerase chain reaction. Levels of SHH, GLI2 and BMP4 proteins were assessed by immunohistochemistry and Western blotting. The expressions of SHH, GLI2 and BMP4 were significantly lower in patients with high-type compared with those with low-type anomalies and controls. Patients with low-type ARMs differed from controls only in the expression of GLI2 mRNA. It is concluded that down-regulation of the SHH/BMP4 signalling pathway may be related to the occurrence of high-type ARMs, but the mechanism responsible for low-type ARMs remains unclear.

Keywords

Anorectal malformations SHH/BMP4 signalling pathway Gene expression Immunohistochemistry Reverse transcription-Polymerase chain reaction (RT-PCR)Western blotting

References

Cuschieri

: Descriptive epidemiology of isolated anal anomalies: A survey of 4.6 million births in Europe. Am J Med Genet 2001; 103: 207–215.

Goyal

Williams

Kenny

: Functional outcome and quality of life in anorectal malformations. J Pediatr Surg 2006; 41: 318–322.

Beasley

Frizelle

: Clarification of the processes that lead to anorectal malformations in the ETU-induced rat model of imperforate anus. J Pediatr Surg 2002; 37: 1305–1312.

Kluth

Hillen

Lambrecht

: The principles of normal and abnormal hindgut development. J Pediatr Surg 1995; 30: 1143–1147.

Fairbanks

De Langhe

Sala

: Fibroblast growth factor 10 (Fgf10) invalidation results in anorectal malformation in mice. J Pediatr Surg 2004; 39: 360–365.

Papapetrou

Drummond

Reardon

: A genetic study of the human T gene and its exclusion as a major candidate gene for sacral agenesis with anorectal atresia. J Med Genet 1999; 36: 208–213.

Kiefer

Ohlemiller

Yang

: Expression of a truncated Sall1 transcriptional repressor is responsible for Townes-Brocks syndrome birth defects. Hum Mol Genet 2003; 12: 2221–2227.

Cohen

Jr : The hedgehog signaling network. Am J Med Genet A 2003; 123A: 5–28.

Roberts

: Molecular mechanisms of development of the gastrointestinal tract. Dev Dyn 2000; 219: 109–120.

10.

Kim

Zhang

: Anorectal malformations caused by defects in sonic hedgehog signaling. Am J Pathol 2001; 159: 765–774.

11.

De Santa

Barbara P

Williams

Goldstein

: Bone morphogenetic protein signaling pathway plays multiple roles during gastrointestinal tract development. Dev Dyn 2005; 234: 312–322.

12.

Liem

Jr Jessell

Briscoe

: Regulation of the neural patterning activity of sonic hedgehog by secreted BMP inhibitors expressed by notochord and somites. Development 2000; 127: 4855–4866.

13.

Zhao

Qiao

Harris

: The zinc finger transcription factor Gli2 mediates bone morphogenetic protein 2 expression in osteoblasts in response to hedgehog signaling. Mol Cell Biol 2006; 26: 6197–6208.

14.

Spilde

Bhatia

Mehta

: Defective sonic hedgehog signaling in esophageal atresia with tracheoesophageal fistula. Surgery 2003; 134: 345–350.

15.

Sukegawa

Narita

Kameda

: The concentric structure of the developing gut is regulated by Sonic hedgehog derived from endodermal epithelium. Development 2000; 127: 1971–1980.

16.

Roberts

Smith

Goff

: Epithelial-mesenchymal signaling during the regionalization of the chick gut. Development 1998; 125: 2791–2801.

17.

Ishizuya-Oka

Hasebe

: Sonic hedgehog and bone morphogenetic protein-4 signaling pathway involved in epithelial cell renewal along the radial axis of the intestine. Digestion 2008; 77 (suppl 1): 42–47.

18.

De Santa

Barbara P

Van den Brink

Roberts

: Development and differentiation of the intestinal epithelium. Cell Mol Life Sci 2003; 60: 1322–1332.

19.

Mandhan

Quan

Beasley

: Sonic hedgehog, BMP4, and Hox genes in the development of anorectal malformations in ethylenethiourea-exposed fetal rats. J Pediatr Surg 2006; 41: 2041–2045.

20.

Sasaki

Iwai

Tsuda

: Sonic hedgehog and bone morphogenetic protein 4 expressions in the hindgut region of murine embryos with anorectal malformations. J Pediatr Surg 2004; 39: 170–173.