Bone morphogenetic protein 4 mediates apoptosis of capillary endothelial cells during rat pupillary membrane regression.
Programmed capillary regression is essential for development, but little is known about the mechanism behind this phenomenon. In this study, we characterized the molecular determinants of capillary regression utilizing the pupillary membrane (PM) in the newborn rat's eye. We observed in the 1-day-culture system that apoptotic endothelial cells decrease in number with the addition of a natural antagonist, Noggin, strongly suggesting the involvement of the bone morphogenetic protein (BMP) family in PM regression. In addition, the lens-conditioned medium (Lens-CM) induced apoptosis of HUVE cells and inhibited endothelial tubulogenesis, which were completely blocked by both Noggin and the BMP4-specific neutralizing antibody. Activation of BMP4 pathway in endothelial cells was confirmed by both the up-regulation of Msx genes correlated with apoptosis and the translocation of Smad1 into the nucleus. We showed a transient expression of BMP4 in Lens-CM by immunoprecipitation assay. Furthermore, the transcorneal injection of BMP4 in rats enhanced the apoptosis of PMs, while that of Noggin attenuated it. These results indicate that BMP4 pathways play pivotal roles in capillary regression in a paracrine manner between lens and PMs.
Kiyono
Mari
M
Department of Genetics, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan.
Shibuya
Masabumi
M
D000818:Animals; D017209:Apoptosis; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002196:Capillaries / Q000166:cytology*; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D018920:Coculture Techniques; D003315:Cornea / Q000378:metabolism; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology*; D018398:Homeodomain Proteins / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism; D008024:Ligands; D008222:Lymphokines / Q000378:metabolism; D051957:MSX1 Transcription Factor; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009924:Organ Culture Techniques; D010766:Phosphorylation; D011233:Precipitin Tests; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013347:Subcellular Fractions; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D051020:bcl-X Protein; D000099176:Noggin Protein
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D008222:Lymphokines; D051957:MSX1 Transcription Factor; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D051020:bcl-X Protein; D000099176:Noggin Protein; C494813:Bcl2l1 protein, rat; C525811:Bmp4 protein, rat; C084119:MSX2 protein; C497998:Msx1 protein, rat