Details

Autor(en) / Beteiligte

• Zhao, Jingsong
• Bu, Ding
• Lee, Matt
• Slavkin, Harold C.
• Hall, Frederick L.
• Warburton, David

Titel

Abrogation of Transforming Growth Factor-β Type II Receptor Stimulates Embryonic Mouse Lung Branching Morphogenesis in Culture

Ist Teil von

• Developmental biology, 1996-11, Vol.180 (1), p.242-257

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1996

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• TGF-β1 is a known inhibitor of branching morphogenesis when added exogenously to mouse embryonic lungs in culture. However, the issue of whether endogenous TGF-β signaling has a function in the process of lung organogenesis is not completely resolved. We utilized immunoperturbation and antisense oligodeoxynucleotide inhibitory strategies to abrogate TGF-β type II receptor function in embryonic mouse lungs undergoing branching morphogenesis in serumless explant culture. Antisera directed against a TGF-β type II receptor N-terminal peptide that perturbs TGF-β ligand–receptor binding increased branching by 70%. Similarly, antisense TGF-β type II receptor oligodeoxynucleotides (40 μM) resulted in a 58% increase in branching, compared to scrambled and mismatched sequence controls, while TGF-β type II receptor mRNA and its protein expression levels were suppressed by 95 and 84%, respectively. Addition of exogenous TGF-β1 did not overcome the stimulatory effects either of TGF-β type II receptor immunoperturbation or of antisense oligodeoxynucleotide treatment on lung branching morphogenesis. Usingin situhybridization and immunohistochemistry, both TGF-β type II receptor mRNA and protein were localized to the epithelium lining the developing airways, and to the surrounding mesenchyme, indicating that TGF-β type II receptor is an important regulator of epithelial–mesenchymal interaction. Exogenous TGF-β1 decreased cyclin A mRNA levels in control embryonic lung explants, while TGF-β type II receptor antisense oligodeoxynucleotides prevented the downregulation of cyclin A mRNA expression by exogenous TGF-β1. In addition, PCNA immunostaining of the primitive bronchial epithelium was increased in the presence of TGF-β type II receptor antisense oligodeoxynucleotides either alone or together with exogenous TGF-β1, whereas TGF-β1 alone decreased PCNA staining. Thus, abrogation of TGF-β type II receptor expression prevented TGF-β1-induced epithelial cell G1arrest. These results demonstrate, for the first time, that abrogation of the TGF-β type II receptor stimulates embryonic lung organogenesis in culture and reverses the negative influence of endogenous TGF-β signaling upon epithelial cell cycle progression.