Effects of bone morphogenic proteins and transforming growth factor-beta on In-vitro production of endothelin-1 by human pulmonary microvascular endothelial cells.
BACKGROUND
Altered endothelial cell (EC)-derived mediator levels, including increased endothelin-1 (ET-1), are hallmarks of human pulmonary arterial hypertension (PAH). Gene mutations for receptors for bone morphogenic proteins (BMP), or transforming growth factor-beta (TGF-beta) cause heritable PAH. The effects of BMPs and TGF-beta on ET-1 production by human pulmonary microvascular EC (HMVEC-LBl) are unknown.


METHODS
HMVEC-LBl were exposed in-vitro to BMPs 2, 4, and 7 or TGF-beta1 in basal or complete medium. ET production was measured, as well as total cellular protein. Levels of Smad 5 and phosphorylated Smads 1/5 were also measured.


RESULTS
BMP-4 did not increase ET-1 while BMP-2 increased it minimally in basal medium. BMP-7 increased ET-1, but only at 100 ng/ml. By contrast, TGF-beta increased ET-1 throughout most of the studied dose range. All BMPs and TGF-beta increased levels of phosphorylated Smads 1/5 without depleting levels of Smad 5.


CONCLUSIONS
With the exception of BMP-7 at high-concentrations, the BMPs that interact with BMP receptor 2, the receptor implicated in heritable PAH, do not or minimally modulate in-vitro constitutive ET-1 production by HMVEC-LBl. TGF-beta increases ET-1 synthesis, and this may have clinical relevance in PAH.
Center for Pulmonary Vascular Disease, Division of Cardiology and Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
Gregory P
GP
Star
Michele
M
Giovinazzo
David
D
Langleben
D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism / Q000494:pharmacology; D055415:Bone Morphogenetic Protein 4 / Q000378:metabolism / Q000494:pharmacology; D055419:Bone Morphogenetic Protein 7 / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D008833:Microcirculation; D010766:Phosphorylation / Q000187:drug effects; D051898:Smad1 Protein / Q000378:metabolism; D051902:Smad5 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism / Q000494:pharmacology
D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019332:Endothelin-1; C497399:SMAD1 protein, human; C497797:SMAD5 protein, human; D051898:Smad1 Protein; D051902:Smad5 Protein; D053773:Transforming Growth Factor beta1