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Role of NADPH oxidase 4 in lipopolysaccharide-induced proinflammatory responses by human aortic endothelial cells

  1. Hye Sun Parka,1,
  2. Jung Nyeo Chuna,1,
  3. Hye Young Junga,
  4. Chulhee Choib,* and
  5. Yun Soo Baea,*
  1. aDivision of Molecular Life Sciences, Center for Cell Signaling Research, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul 120-750, Republic of Korea
  2. bDepartment of Biosystems, Korea Advanced Institute of Science and Technology, 373-1 Guseong-Dong, Yuseong-Gu, Daejeon, Republic of Korea
  1. *Corresponding authors. Bae is to be contacted at Tel.: +82 2 3277 2729; fax: +82 2 3277 3760. Choi, Tel.: +82 42 869 4321; fax: +82 42 869 4310. Email address: cchoi{at}kaist.ac.kr baeys{at}ewha.ac.kr
  • Received May 3, 2006.
  • Revision received July 21, 2006.
  • Accepted September 18, 2006.

Abstract

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

Methods and 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-κB 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.

Keywords

Key words

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