Role of NADPH oxidase 4 in lipopolysaccharide-induced proinflammatory responses by human aortic endothelial cells.
OBJECTIVE
We investigated the role of NADPH oxidase 4 (Nox4) on lipopolysaccharide (LPS)-induced proinflammatory responses by human aortic endothelial cells (HAECs).


RESULTS
Yeast two-hybrid and glutathione-S-transferase pull-down assays indicated that the cytosolic Toll/IL-1R region of Toll-like receptor 4 (TLR4) (amino acids 739-769) is the responsible domain for interaction with the COOH terminal of Nox4 (amino acids 451-530). Consistently, overexpression of the COOH-terminal region of Nox4 inhibited nuclear factor-kappaB activation in response to LPS. Downregulation of Nox4 by transfection of siRNA specific to Nox4 in HAECs resulted in a failure to induce reactive oxygen species (ROS) generation and subsequent expression of intercellular adhesion molecule-1 (ICAM-1) and chemokines such as IL-8 and monocyte chemoattractant protein-1 (MCP-1) in response to LPS. Furthermore, transient transfection of endothelial cells with Nox4 siRNA led to a decrease in migration and adhesion of monocytes in response to LPS by 36% and 52%, respectively.


CONCLUSIONS
Nox4 plays a central role in LPS-induced proinflammatory responses by endothelial cells in an ROS-dependent manner.
Park
Hye Sun
HS
Division of Molecular Life Sciences, Center for Cell Signaling Research, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul 120-750, Republic of Korea.
Chun
Jung Nyeo
JN
Jung
Hye Young
HY
Choi
Chulhee
C
Bae
Yun Soo
YS
D001011:Aorta; D001424:Bacterial Infections / Q000201:enzymology / Q000276:immunology*; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000032:analysis; D042783:Endothelial Cells / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection / Q000379:methods; D020798:Two-Hybrid System Techniques
C111835:CCL2 protein, human; D018932:Chemokine CCL2; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; D034741:RNA, Small Interfering; D018799:Intercellular Adhesion Molecule-1; D006861:Hydrogen Peroxide; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human