The role of transforming growth factor-beta 2 and 3 in formation of ventral body wall in the cadmium-induced omphalocele chick model.
OBJECTIVE
In the chick embryo, the administration of cadmium (Cd) induces ventral body wall defects (VBWDs) similar to the human omphalocele. Transforming growth factors beta (TGFs-beta) are involved in many developmental processes, including ventral body wall formation. The Tgfbeta2(-/-) Tgfbeta3(-/-) double knockout mice and Tgfbeta2(-/-) Tgfbeta3(+/-) mutants show VBWD, whereas Tgfbeta2(+/-) Tgfbeta3(-/-) mutants display normal ventral body wall fusion. We designed this study to investigate the messenger RNA (mRNA) levels of TGF-beta2 and TGF-beta3 in the Cd-induced omphalocele chick model during early embryogenesis.


METHODS
Chick embryos were exposed to either Cd or saline, harvested 1 hour (1H), 4H, and 8H after treatment and then divided into 2 groups: control and Cd (n = 8 at each time-point, respectively). Reverse transcription polymerase chain reaction was performed to evaluate the mRNA levels of TGF-beta2 and TGF-beta3 and statistically analyzed.


RESULTS
The mRNA expression levels of TGF-beta2 at 1H were significantly decreased in the Cd group compared to controls (P < .05). However, the levels of TGF-beta3 were not altered at all the time-points studied.


CONCLUSIONS
We provide evidence, for the first time, that TGF-beta2 gene expression is downregulated during a narrow window of early embryogenesis in the Cd chick model. Our data show that TGF-beta2 is the key gene involved in the formation of ventral body wall.
Doi
Takashi
T
The Children's Research Center, Our Lady's Children's Hospital, Dublin, Ireland.
Puri
Prem
P
Bannigan
John
J
Thompson
Jennifer
J
D034861:Abdominal Wall / Q000196:embryology; D000818:Animals; D002104:Cadmium; D002642:Chick Embryo; D006554:Hernia, Umbilical / Q000196:embryology*; D012333:RNA, Messenger / Q000032:analysis; D053781:Transforming Growth Factor beta2 / Q000378:metabolism*; D053782:Transforming Growth Factor beta3 / Q000378:metabolism*
D012333:RNA, Messenger; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3; D002104:Cadmium