Abstract
Aim Pulmonary hypertension (PH) is a severe complication of congenital diaphragmatic
hernia (CDH). Transforming growth factor-β (TGFβ) signaling is suggested to be involved
in PH development by regulating embryonic angiogenesis, cell proliferation, and cell
differentiation. Altered TGFβ signaling has been demonstrated in experimental CDH
lungs. Elastin microfibril interfacer 1 (Emilin-1) is an extracellular matrix glycoprotein
expressed in endothelial and vascular smooth muscle cells and known to regulate TGFβ
processing and arterial diameter. We designed this study to investigate the pulmonary
vascular expression of Emilin-1 in nitrofen-induced CDH rats.
Materials and Methods Following ethical approval (REC913b, REC1103), time-pregnant Sprague Dawley rats
received nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on
D21 and divided into CDH group and control group. Quantitative real-time polymerase
chain reaction (n = 11 each group), Western blot analysis, and confocal microscopy were used to determine
the gene and protein expression of Emilin-1.
Main Results Relative Emilin-1 messenger RNA (ribonucleic acid) levels were significantly downregulated
in CDH lung tissue compared with controls (CDH: 0.043 ± 0.003; control: 0.067 ± 0.004;
p < 0.001). Western blotting confirmed the decreased pulmonary Emilin-1 protein expression
in CDH lungs. Confocal microscopy demonstrated a markedly diminished expression of
Emilin-1 in the CDH pulmonary vasculature compared with controls.
Conclusion To our knowledge, this study demonstrates for the first time a decreased Emilin-1
gene and protein expression in the pulmonary vasculature of nitrofen-induced CDH.
Emilin-1 deficiency through its interaction with TGFß may result in abnormal vascular
remodeling resulting in PH in this model.
Keywords
Emilin-1 - TGFβ - congenital diaphragmatic hernia - nitrofen - pulmonary hypertension
