Abstract
Heme oxygenase-1 (HO-1) is an inducible enzyme that degrades heme to carbon monoxide, iron ions, and biliverdin. Its expression can be induced by 15-deoxy-Delta(12,14)prostaglandin-J(2) (15d-PGJ(2)), a natural ligand of peroxisome proliferator-activated receptor-gamma transcription factor. In macrophages and vascular smooth muscle cells, 15d-PGJ(2) up-regulates the expression of vascular endothelial growth factor (VEGF), a fundamental regulator of angiogenesis. Here we investigated the involvement of HO-1 in the 15d-PGJ(2)-mediated regulation of VEGF production by human microvascular endothelial cells (HMEC-1). Resting HMEC-1 released approximately 20 pg/ml VEGF protein after 24 h of incubation. Treatment of cells with 15d-PGJ(2) (1-10 microM) significantly and dose-dependently increased the VEGF promoter activity, mRNA expression, and protein secretion. In the same cells, 15d-PGJ(2) potently induced the expression of HO-1 protein that correlated with HO-1 promoter activity. Activation of HO-1 with hemin or ectopic overexpression of HO-1 in HMEC-1 perfectly mimicked the effect of 15d-PGJ(2) and led to increased VEGF production. Importantly, the inhibition of the HO-1 pathway by tin protoporphyrin-IX significantly reduced the stimulatory effect of 15d-PGJ(2) on VEGF synthesis. Thus, we postulate that the up-regulation of VEGF expression in response to 15d-PGJ(2 )in HMEC-1 is mediated by the activation of HO-1.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Line
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Endothelial Growth Factors / biosynthesis*
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Endothelial Growth Factors / genetics
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Endothelium, Vascular / cytology
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Endothelium, Vascular / drug effects*
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Endothelium, Vascular / metabolism
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Enzyme Activation
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Enzyme Induction
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation
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Genes, Reporter
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Heme Oxygenase (Decyclizing) / antagonists & inhibitors
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Heme Oxygenase (Decyclizing) / genetics
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Heme Oxygenase (Decyclizing) / metabolism*
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Heme Oxygenase-1
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Hemin / pharmacology
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Humans
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Intercellular Signaling Peptides and Proteins / biosynthesis*
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Intercellular Signaling Peptides and Proteins / genetics
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Interleukin-8 / metabolism
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Lymphokines / biosynthesis*
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Lymphokines / genetics
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Membrane Proteins
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Mice
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Photosensitizing Agents / chemistry
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Photosensitizing Agents / metabolism
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Promoter Regions, Genetic
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Prostaglandin D2 / analogs & derivatives*
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Prostaglandin D2 / pharmacology*
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Protoporphyrins / chemistry
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Protoporphyrins / metabolism
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RNA, Messenger / metabolism
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
Substances
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Endothelial Growth Factors
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Enzyme Inhibitors
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Intercellular Signaling Peptides and Proteins
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Interleukin-8
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Lymphokines
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Membrane Proteins
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Photosensitizing Agents
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Protoporphyrins
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RNA, Messenger
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
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9-deoxy-delta-9-prostaglandin D2
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Hemin
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protoporphyrin IX
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HMOX1 protein, human
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Heme Oxygenase (Decyclizing)
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Heme Oxygenase-1
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Hmox1 protein, mouse
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Prostaglandin D2