TY - JOUR
T1 - Hypoxia-inducible factors in the first trimester human lung
AU - Groenman, Frederick
AU - Rutter, Martin
AU - Caniggia, Isabella
AU - Tibboel, Dick
AU - Post, Martin
PY - 2007/4/1
Y1 - 2007/4/1
N2 - Lung development takes place in a relatively low-oxygen environment, which is beneficial for lung organogenesis, including vascular development. Hypoxia-inducible factor (HIF)-1 plays an important role in mediating oxygen-regulated events. HIF-1 is stable and initiates gene transcription under hypoxia, whereas in normoxia, interaction with the von Hippel-Lindau (VHL) tumor suppressor protein leads to rapid degradation of the HIF-1α subunit. Interaction with VHL requires hydroxylation of HIF-1α proline residues by prolyl hydroxylases (PHDs). We investigated the expression of the various components regulating HIF-1α stability in first trimester (8-14 weeks) human lungs. Spatial expression was assessed by immunohistochemistry and temporal expression by quantitative PCR. Immunoreactivity for PHD1, PHD3, and seven in absentia homolog (SIAH)1 was noted in the pulmonary epithelium. PHD2 was not expressed in the airway epithelium, but in the lung parenchyma. HIF-1α and vascular endothelial growth factor (VEGF) immunoreactivity were primarily detected in the branching epithelium. HIF-2α and ARNT proteins localized to the developing epithelium as well as mesenchymal, most likely vascular, structures in the parenchyma. VEGF receptor 2 (VEGFR2) was found in the subepithelium as well as in vascular structures of the mesenchyme. All components of the VEC complex (VHL, NEDD8, and Cullin2) were found in the epithelium. Quantitative PCR analysis demonstrated that VEGF, VEGFR1, HIF-1α, HIF-2α, ARNT, PHD1, PHD2, PHD3, and SIAH1 gene expression was constant during early pulmonary organogenesis. Cumulatively, the data suggest that the lung develops in a low-oxygen environment that allows for proper vascular development through HIF-regulated pathways.
AB - Lung development takes place in a relatively low-oxygen environment, which is beneficial for lung organogenesis, including vascular development. Hypoxia-inducible factor (HIF)-1 plays an important role in mediating oxygen-regulated events. HIF-1 is stable and initiates gene transcription under hypoxia, whereas in normoxia, interaction with the von Hippel-Lindau (VHL) tumor suppressor protein leads to rapid degradation of the HIF-1α subunit. Interaction with VHL requires hydroxylation of HIF-1α proline residues by prolyl hydroxylases (PHDs). We investigated the expression of the various components regulating HIF-1α stability in first trimester (8-14 weeks) human lungs. Spatial expression was assessed by immunohistochemistry and temporal expression by quantitative PCR. Immunoreactivity for PHD1, PHD3, and seven in absentia homolog (SIAH)1 was noted in the pulmonary epithelium. PHD2 was not expressed in the airway epithelium, but in the lung parenchyma. HIF-1α and vascular endothelial growth factor (VEGF) immunoreactivity were primarily detected in the branching epithelium. HIF-2α and ARNT proteins localized to the developing epithelium as well as mesenchymal, most likely vascular, structures in the parenchyma. VEGF receptor 2 (VEGFR2) was found in the subepithelium as well as in vascular structures of the mesenchyme. All components of the VEC complex (VHL, NEDD8, and Cullin2) were found in the epithelium. Quantitative PCR analysis demonstrated that VEGF, VEGFR1, HIF-1α, HIF-2α, ARNT, PHD1, PHD2, PHD3, and SIAH1 gene expression was constant during early pulmonary organogenesis. Cumulatively, the data suggest that the lung develops in a low-oxygen environment that allows for proper vascular development through HIF-regulated pathways.
KW - Development
KW - Human
KW - Hypoxia-inducible factor
KW - Pulmonary vascularization
UR - http://www.scopus.com/inward/record.url?scp=33947599958&partnerID=8YFLogxK
U2 - https://doi.org/10.1369/jhc.6A7129.2006
DO - https://doi.org/10.1369/jhc.6A7129.2006
M3 - Article
C2 - 17189520
SN - 0022-1554
VL - 55
SP - 355
EP - 363
JO - Journal of Histochemistry and Cytochemistry
JF - Journal of Histochemistry and Cytochemistry
IS - 4
ER -