Vitamin D3-upregulated protein-1 (VDUP-1) regulates redox-dependent vascular smooth muscle cell proliferation through interaction with thioredoxin.
Reactive oxygen species are important cellular signaling molecules, and thioredoxin (TRX) is a key regulator of cellular redox balance. We investigated the interaction of TRX with its endogenous inhibitor, vitamin D3-upregulated protein (VDUP)-1, in human aortic smooth muscle cells (SMCs). Adenoviral gene transfer of TRX enhanced TRX enzyme activity 2.7+/-0.4-fold (P<0.05 versus cells infected with adenoviral vector expressing green fluorescent protein [AdGFP]) and resulted in a 3.8+/-0.5-fold increase of cellular DNA synthesis as detected by methyl-[3H]thymidine incorporation (P<0.001). Platelet-derived growth factor (PDGF) also increased TRX enzyme activity 2.5+/-3.3-fold (P<0.05 versus no stimulation) and DNA synthesis 6.5+/-0.3-fold (P<0.001 versus no stimulation) without significant changes in TRX expression. PDGF and H2O2 time-dependently suppressed VDUP-1 expression (13-fold and 30-fold reduction after 1 hour, respectively; P<0.001), and this was inhibited by the cell-permeable antioxidants N-acetylcysteine and 4,5-dihydroxy-1,3-benzene-disulfonic acid (Tiron). Overexpression of VDUP-1 (AdVDUP-1) reduced TRX activity at baseline (-61+/-23% versus control cells, P<0.05) and abolished PDGF-induced TRX activity (-9+/-27% in AdVDUP-1-infected cells; P=NS versus control cells). In addition, overexpression of VDUP-1 blocked PDGF-induced DNA synthesis (1.3+/-0.4-fold increase in AdVDUP-1-infected cells versus 6.5+/-0.4-fold increase in AdGFP-infected cells, P<0.001). In conclusion, VDUP-1 has marked antiproliferative effects in SMCs through the suppression of TRX activity, suggesting that the regulation of VDUP-1 is a critical molecular switch in the transduction of pro-oxidant mitogenic signals. These data also demonstrate that activation of the reductase TRX plays a pivotal role in the redox-dependent proliferation of SMCs.
Schulze
P Christian
PC
Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA.
De Keulenaer
Gilles W
GW
Yoshioka
Jun
J
Kassik
Kimberly A
KA
Lee
Richard T
RT
D021581:Active Transport, Cell Nucleus; D000256:Adenoviridae / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D005822:Genetic Vectors; D006801:Humans; D008954:Models, Biological; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000096:biosynthesis; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D002352:Carrier Proteins; D012333:RNA, Messenger; C486715:TXNIP protein, human; D013879:Thioredoxins