Functional role of CD105 in TGF-beta1 signalling in murine and human endothelial cells.
BACKGROUND
Angiogenesis is important in health and several disease states. CD105 is a proliferation-associated and hypoxia-inducible transmembrane protein abundantly expressed in angiogenic endothelial cells. CD105 is a receptor for transforming growth factors (TGF)-beta1 and -beta3. The exact mechanisms for CD105 regulation of vascular development have not been fully elucidated.


METHODS
In this study, an antisense approach to create a murine and a human stably transfected endothelial cell line expressing a reduction in CD105 protein was used.


RESULTS
We showed that inhibition of CD105 in cultured murine and human endothelial cells enhanced the ability of TGF-beta1 to suppress growth and migration, and influenced TGF-beta1 promoter activity. TGF-beta1 not only reduced the length of the capillary-like structures, but also caused mortality in CD105-deficient murine antisense cells compared to control cultures. To determine whether CD105 affected TGF-beta1-induced gene expression, a luciferase assay in transiently transfected cells with p3TP-Lux promoter constructs was performed. Both murine and human antisense transfectants showed a significant increase in p3TP-Lux promoter activity. Further studies on the functional importance of CD105 was undertaken in irradiated normoxic and hypoxic cells. The levels of pro- and anti-apoptotic markers were also evaluated. There was an increase in pro-apoptotic marker (p53), but a reduction in anti-apoptotic marker (Bcl-2) in CD105-deficient cells.


CONCLUSIONS
These results provide direct evidence that CD105 antagonises the inhibitory effects of TGF-beta1 on human and murine vascular endothelial cells and that normal cellular levels of CD105 are required for the formation of new blood vessels.
Warrington
Kelly
K
Division of Laboratory and Regenerative Medicine, Medical School, The University of Manchester M13 9PT, UK.
Hillarby
M Chantal
MC
Li
Chenggang
C
Letarte
Michelle
M
Kumar
Shant
S
D000818:Animals; D015703:Antigens, CD; D048708:Cell Growth Processes / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D016373:DNA, Antisense / Q000235:genetics; D000071063:Endoglin; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D051379:Mice; D016372:RNA, Antisense / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000502:physiology*; D053773:Transforming Growth Factor beta1; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
D015703:Antigens, CD; D016373:DNA, Antisense; C064206:ENG protein, human; D000071063:Endoglin; D016372:RNA, Antisense; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D016159:Tumor Suppressor Protein p53; D019010:Vascular Cell Adhesion Molecule-1