Effects of the blood coagulation vitamin K as an inhibitor of arterial calcification.
BACKGROUND
The transformation of smooth muscle cells (VSMCs) in the vessel wall to osteoblast like cells is known to precede arterial calcification which may cause bleeding complications. The vitamin K-dependent protein MGP has been identified as an inhibitor of this process by binding BMP-2, a growth factor known to trigger the transformation. In this study, we determined if the vitamin K-dependent Gla region in MGP by itself can inhibit the growth factor activity of BMP-2 and if menaquinone-4 (MK4) regulates gene expression in VSMCs.


METHODS
A synthetic gamma-carboxyglutamic acid (Gla) containing peptide covering the Gla region in human MGP was used to test its ability to inhibit BMP-2 induced transformation of mouse pro-myoblast C2C12 cells into osteoblasts. MK4 was tested by microarray analysis as a gene regulatory molecule in VSMCs.


CONCLUSIONS
The results show that the Gla - but not the Glu-peptide inhibited the transformation which provide evidence that the Gla region in MGP is directly involved in the BMP-2/MGP interaction and emphasizes the importance of the vitamin K-dependent modification of MGP. From the data obtained from the microarray analysis, we focused on two quantitatively altered cDNAs representing proteins known to be associated with vessel wall calcification. DT-diaphorase of the vitamin K-cycle, showed increased gene expression with a 4.8-fold higher specific activity in MK4 treated cells. Osteoprotegrin gene expression was down regulated and osteoprotegrin protein secretion from the MK4 treated cells was lowered to 1.8-fold. These findings suggest that MK4 acts as an anti-calcification component in the vessel wall.
Wallin
Reidar
R
Department of Internal Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA. rwallin@wfubmc.edu
Schurgers
Leon
L
Wajih
Nadeem
N
D000818:Animals; D000933:Antifibrinolytic Agents / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000166:cytology; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002114:Calcinosis / Q000473:pathology* / Q000517:prevention & control*; D002135:Calcium-Binding Proteins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D016326:Extracellular Matrix Proteins / Q000494:pharmacology; D006801:Humans; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects*; D032446:Myoblasts / Q000166:cytology; D010006:Osteoblasts / Q000166:cytology; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014812:Vitamin K / Q000494:pharmacology*; D024482:Vitamin K 2 / Q000031:analogs & derivatives / Q000494:pharmacology; D000097568:Matrix Gla Protein
D000933:Antifibrinolytic Agents; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D010446:Peptide Fragments; D016212:Transforming Growth Factor beta; D014812:Vitamin K; D024482:Vitamin K 2; D000097568:Matrix Gla Protein; C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; C525720:Bmp2 protein, rat; C030814:menatetrenone