A significant role for the heme oxygenase-1 gene in endothelial cell cycle progression.
Heme oxygenase (HO) catalyzes the conversion of heme to biliverdin with the release of iron and carbon monoxide. HO-1 is inducible by inflammatory conditions, which cause oxidative stress in endothelial cells. Overexpression of human HO-1 in endothelial cells may have the potential to provide protection against a variety of agents that cause oxidative stress. We investigated the physiological significance of human HO-1 overexpression, using a retroviral vector, on cell cycle progression in the presence and absence of pyrrolidine dithiocarbamate (PDTC). The addition of PDTC (25 and 50 microM) to human microvessel endothelial cells over 24 h resulted in significant (P < 0.05) abnormalities in DNA distribution and cell cycle progression compared to cells overexpressing the HO-1 gene. The addition of PDTC resulted in a significantly decreased G(1) phase and an increased G(2)/M phase in the control cells, but not in cells transduced with the human HO-1 gene (P < 0.05). Further, PDTC had a potent effect on DNA distribution abnormalities in exponentially grown cells compared to subconfluent cells. Upregulation of HO activity in endothelial cells, as a result of overexpressing human HO-1, prevented PDTC-mediated abnormalities in DNA distribution. Inhibition of HO activity by tin-mesoporphyrin (SnMP) (30 microM) resulted in enhancement of PDTC-mediated abnormalities in cell cycle progression. Bilirubin or iron did not mediate DNA distribution. We conclude that an increase in endothelial cell HO-1 activity with subsequent generation of carbon monoxide, elicited by gene transfer, reversed the PDTC-mediated abnormalities in cell cycle progression and is thus a potential therapeutic means for attenuating the effects of oxidative stress-causing agents.
Kushida
Taketoshi
T
Department of Medicine and Pharmacology, New York Medical College, Valhalla, New York 10595, USA.
Quan
Shuo
S
Yang
Liming
L
Ikehara
Susumu
S
Kappas
Attallah
A
Abraham
Nader G
NG
D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001664:Biliverdine / Q000494:pharmacology; D002248:Carbon Monoxide / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D051547:Heme Oxygenase-1; D006801:Humans; D007501:Iron / Q000494:pharmacology; D008565:Membrane Proteins; D008665:Metalloporphyrins / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012190:Retroviridae / Q000235:genetics; D013859:Thiocarbamates / Q000494:pharmacology; D014162:Transfection
D000975:Antioxidants; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D008665:Metalloporphyrins; D011759:Pyrrolidines; D013859:Thiocarbamates; C055421:tin mesoporphyrin; C020972:pyrrolidine dithiocarbamic acid; D002248:Carbon Monoxide; D004247:DNA; D007501:Iron; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D001664:Biliverdine