Colocalization of TGF-beta 1 and collagen I and III, fibronectin and glycosaminoglycans during lung branching morphogenesis.
The possible in vivo role of TGF-beta 1 in regulating various proteins of the extracellular matrix, including fibronectin, collagen I and III, and glycosaminoglycans, was examined by immunohistochemical methods during critical stages of lung morphogenesis in the 11- to 18-day-old mouse embryo. Sections of Bouin-fixed, paraffin-embedded whole embryos were exposed to polyclonal antibodies specific to synthetic peptides present in the precursor part of TGF-beta 1 (pro-TGF-beta 1), in the processed TGF-beta 1 (antibody CC), collagen I and III, fibronectin, followed by the PAP or ABC technique to visualize the location of the antibody. GAG were stained with Alcian Blue 8GX. Our results indicate colocalization of TGF-beta 1 expression and that of matrix proteins in the developing lung when branching morphogenesis (cleft formation) and tissue stabilization occur. The presence of TGF-beta 1 at the epithelial-mesenchymal interfaces of stalks and clefts at a time when matrix proteins can first be visualized in these areas, suggests a direct participation of the growth factor in the development of the basic architecture of the lung.
Heine
U I
UI
Biological Carcinogenesis and Development Program, National Cancer Institute, Frederick Cancer Research Facility, Maryland 21701.
Munoz
E F
EF
Flanders
K C
KC
Roberts
A B
AB
Sporn
M B
MB
D000818:Animals; D003094:Collagen / Q000032:analysis*; D005109:Extracellular Matrix / Q000737:chemistry; D005353:Fibronectins / Q000032:analysis*; D006025:Glycosaminoglycans / Q000032:analysis*; D007150:Immunohistochemistry; D008168:Lung / Q000737:chemistry* / Q000196:embryology; D051379:Mice; D009024:Morphogenesis; D016212:Transforming Growth Factor beta / Q000032:analysis*
D005353:Fibronectins; D006025:Glycosaminoglycans; D016212:Transforming Growth Factor beta; D003094:Collagen