1. PECAM-1-dependent heme oxygenase-1 regulation via an Nrf2-mediated pathway in endothelial cells.
- Author
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Saragih H, Zilian E, Jaimes Y, Paine A, Figueiredo C, Eiz-Vesper B, Blasczyk R, Larmann J, Theilmeier G, Burg-Roderfeld M, Andrei-Selmer LC, Becker JU, Santoso S, and Immenschuh S
- Subjects
- Active Transport, Cell Nucleus, Animals, CHO Cells, Cell Line, Cricetinae, Cricetulus, GPI-Linked Proteins metabolism, Gene Knockdown Techniques, Heme Oxygenase-1 genetics, Human Umbilical Vein Endothelial Cells, Humans, Isoantigens metabolism, L Cells, Mice, Myeloblastin metabolism, Platelet Endothelial Cell Adhesion Molecule-1 genetics, RNA, Messenger genetics, RNA, Messenger metabolism, Reactive Oxygen Species metabolism, Receptors, Cell Surface metabolism, Signal Transduction, Up-Regulation, Endothelial Cells metabolism, Heme Oxygenase-1 metabolism, NF-E2-Related Factor 2 metabolism, Platelet Endothelial Cell Adhesion Molecule-1 metabolism
- Abstract
The antioxidant enzyme heme oxygenase (HO)-1, which catalyses the first and rate-limiting step of heme degradation, has major anti-inflammatory and immunomodulatory effects via its cell-type-specific functions in the endothelium. In the current study, we investigated whether the key endothelial adhesion and signalling receptor PECAM-1 (CD31) might be involved in the regulation of HO-1 gene expression in human endothelial cells (ECs). To this end PECAM-1 expression was down-regulated in human umbilical vein ECs (HUVECs) by an adenoviral vector-based knockdown approach. PECAM-1 knockdown markedly induced HO-1, but not the constitutive HO isoform HO-2. Nuclear translocation of the transcription factor NF-E2-related factor-2 (Nrf2), which is a master regulator of the inducible antioxidant cell response, and intracellular levels of reactive oxygen species (ROS) were increased in PECAM-1-deficient HUVECs, respectively. PECAM-1-dependent HO-1 regulation was also examined in PECAM-1 over-expressing Chinese hamster ovary and murine L-cells. Endogenous HO-1 gene expression and reporter gene activity of transiently transfected luciferase HO-1 promoter constructs with Nrf2 target sequences were decreased in PECAM-1 over-expressing cells. Moreover, a regulatory role of ROS for HO-1 regulation in these cells is demonstrated by studies with the antioxidant N-acetylcysteine and exogenous hydrogenperoxide. Finally, direct interaction of PECAM-1 with a native complex of its binding partner NB1 (CD177) and serine proteinase 3 (PR3) from human neutrophils, markedly induced HO-1 expression in HUVECs. Taken together, we demonstrate a functional link between HO-1 gene expression and PECAM-1 in human ECs, which might play a critical role in the regulation of inflammation.
- Published
- 2014
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