Rac-dependent monocyte chemoattractant protein-1 production is induced by nutrient deprivation.
Under ischemic conditions, the vessel wall recruits inflammatory cells. Human aortic endothelial cells (HAECs) exposed to hypoxia followed by reoxygenation produce monocyte chemoattractant protein-1 (MCP-1); however, most experiments have been performed in the presence of nutrient deprivation (ND). We hypothesized that ND rather than hypoxia mediates endothelial MCP-1 production during ischemia, and that the small GTP-binding protein Rac1 and reactive oxygen species (ROS) are involved in this process. ND was generated by shifting HAECs from 10% to 1% FBS. Superoxide production by HAECs was increased 6 to 24 hours after ND, peaking at 18 hours. MCP-1 production was increased over a similar time frame, but peaked later at 24 hours. These effects were blocked by treatment with antioxidants such as superoxide dismutase mimetic and N-acetylcysteine (NAC), or NADPH oxidase inhibitors, DPI and gp91ds-tat. Superoxide and MCP-1 production were enhanced by RacV12 (constitutively active) in the absence of ND, and were inhibited by RacN17 (dominant-negative) adenoviral transduction under ND, suggesting that the small G-protein Rac1 is required. In conclusion, ND, an important component of ischemia, is sufficient to induce MCP-1 production by HAECs, and such production requires a functional Rac1, redox-dependent pathway.
Lopes
Neuza H M
NH
Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
Vasudevan
Sanjay S
SS
Gregg
David
D
Selvakumar
Balakrishnan
B
Pagano
Patrick J
PJ
Kovacic
Herve
H
Goldschmidt-Clermont
Pascal J
PJ
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D000975:Antioxidants / Q000494:pharmacology; D018929:Cell Culture Techniques / Q000379:methods; D002460:Cell Line; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D003470:Culture Media / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
D000975:Antioxidants; D018932:Chemokine CCL2; D003470:Culture Media; D004791:Enzyme Inhibitors; D016328:NF-kappa B; D010455:Peptides; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; C118258:SN50 peptide; D013481:Superoxides; D019255:NADPH Oxidases; D020830:rac1 GTP-Binding Protein