Downregulation of p300 gene expression in airway mesenchyme of nitrofen-induced hypoplastic lungs.
OBJECTIVE
Congenital diaphragmatic hernia (CDH) is a relatively common developmental abnormality causing life-threatening respiratory distress at birth. The nitrofen model has been widely used to investigate the pathogenesis of hypoplastic lungs associated with CDH. Embryos lacking p300 and CBP genes are significantly smaller in lung formation. We hypothesized that pulmonary gene expression of p300 and CBP is downregulated during late gestation in the nitrofen-induced CDH model.


METHODS
Time-pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetal lungs were harvested on D18 and D21 (n = 8 at each time point). Pulmonary gene expression of p300 and CBP was analyzed by quantitative real-time PCR. Immunohistochemistry was performed to investigate expression and localization of pulmonary p300 and CBP proteins.


RESULTS
Relative mRNA expression levels of p300 were significantly decreased in nitrofen-induced hypoplastic lungs on D18 compared to controls (3.00 ± 0.20 vs. 3.76 ± 0.14; p = 0.0039), while CBP levels were not altered. p300 immunoreactivity was markedly diminished in surrounding mesenchymal compartments and nuclei of proximal and distal airway cells, while CBP expression was not altered.


CONCLUSIONS
Downregulation of p300 gene expression during the early canalicular stage may disrupt epithelial-mesenchymal signaling interactions, contributing to the development of hypoplastic lungs in the nitrofen-induced CDH model.
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
Hiromizu
H
Takahashi
Florian
F
Friedmacher
Naho
N
Fujiwara
Alejandro
A
Hofmann
Toshiaki
T
Takahashi
Prem
P
Puri
D000015:Abnormalities, Multiple / Q000139:chemically induced / Q000235:genetics*; D000818:Animals; D015536:Down-Regulation; D050881:E1A-Associated p300 Protein / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation; D065630:Hernias, Diaphragmatic, Congenital / Q000139:chemically induced / Q000235:genetics*; D008168:Lung / Q000002:abnormalities*; D008171:Lung Diseases / Q000139:chemically induced / Q000235:genetics*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D008648:Mesoderm / Q000378:metabolism; D010647:Phenyl Ethers; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
D008565:Membrane Proteins; C408142:Pag1 protein, rat; D010647:Phenyl Ethers; D010750:Phosphoproteins; D050881:E1A-Associated p300 Protein; C494362:Ep300 protein, rat; C007350:nitrofen