Iron Chelators Inhibit VCAM-1 Expression in Human Dermal Microvascular Endothelial Cells

• Published in: Journal of investigative dermatology Vol. 120; no. 5; pp. 871 - 879
• Main Authors: Koo, Sang-Wahn, Casper, Katherine A., Otto, Kristen B., Gira, Amy K., Swerlick, Robert A.
• Format: Journal Article
• Language: English
• Published: Danvers, MA Elsevier Inc 01.05.2003; Nature Publishing; Elsevier Limited
• Subjects: 2,2'-Dipyridyl - pharmacology; adhesion; Biological and medical sciences; Blotting, Western; Cells, Cultured; Chelating Agents - pharmacology; Chromatin - metabolism; Deferoxamine - pharmacology; Dermatology; DNA-Binding Proteins - metabolism; Dose-Response Relationship, Drug; Endothelium; Endothelium, Vascular - metabolism; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Free Radical Scavengers - pharmacology; gene regulation; Humans; Interferon Regulatory Factor-1; Investigative techniques, diagnostic techniques (general aspects); iron; Iron - metabolism; Iron Chelating Agents - pharmacology; Kinetics; Medical sciences; Microscopy, Fluorescence; NF-kappa B - metabolism; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Phosphoproteins - metabolism; Phosphorylation; Reactive Oxygen Species; RNA, Heterogeneous Nuclear - metabolism; RNA, Messenger - metabolism; Serine - metabolism; Skin - metabolism; Transcription, Genetic; Tumor Necrosis Factor-alpha - metabolism; Up-Regulation; Vascular Cell Adhesion Molecule-1 - biosynthesis; iron; adhesion; gene regulation; Endothelium; Human; Cell culture; Microcirculation; Endothelial cell; Vascular cell adhesion molecule 1; Endothelium/gene regulation/adhesion/iron; Chelating agent; Iron; Derm; Gene expression
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1046/j.1523-1747.2003.12144.x

Vascular cell adhesion molecule (VCAM)-1 expression may be coupled to redox-sensitive regulatory pathways, and iron may play a role in generation of reactive oxygen species that participate in these signaling pathways. To investigate the role of iron in TNFα-induced VCAM-1 gene expression, human dermal microvascular endothelial cells (HDMEC) were stimulated with TNFα in the presence of iron chelators and examined for expression of VCAM-1. The iron chelators dipyridyl (DP) and desferoxamine (DFO) inhibited VCAM-1 protein and mRNA induction in a concentration- and time-dependent manner. The induction of VCAM-1 was not inhibited by nonmetal binding reactive oxygen species (ROS) scavengers, implying a direct effect of iron in the expression of these adhesion molecules. The effect of iron was mediated at the level of gene transcription since pretreatment with DP abrogated the TNFα-mediated up-regulation of VCAM-1 heterogeneous nuclear RNA. Pretreatment of HDMEC with DP prior to TNFα treatment had no effect on p65 nuclear localization, DNA binding, or serine phosphorylation. DP pretreatment inhibited TNFα- and IFNγ-mediated interferon regulatory factor 1 (IRF-1) protein expression, although restoration of IRF-1 expression failed to reconstitute VCAM-1 expression. DP treatment also blocked VCAM-1 induction in human umbilical vein endothelium and blocked induction of a host of NF-kB activated genes in HDMEC including ICAM-1, IL-8, and tissue factor. IkBα, an NF-kB inducible and constitutively accessible gene not requiring chromatin remodeling for transcription, was not affected by DP treatment. These data suggest that iron plays a critical role in TNFα mediated VCAM-1 induction in HDMEC, and the target for iron effects may be IRF-1, NF-kB, and potentially chromatin remodeling.