TNF-α-induced ROS production triggering apoptosis is directly linked to Romo1 and Bcl-XL

J. J. Kim, S. B. Lee, J. K. Park, Y. D. Yoo

Research output: Contribution to journalArticlepeer-review

284 Citations (Scopus)

Abstract

Reactive oxygen species (ROS) produced by tumor necrosis factor-α (TNF-α) have an important function in cell death by activating c-Jun N-terminal kinase. However, the exact mechanism of mitochondrial ROS production, after TNF-α stimulation, is not clearly understood. In this study, we determined that ROS modulator 1 (Romo1) and B-cell lymphoma-extra large (Bcl-X L) are directly associated with TNF-α-induced ROS production. In response to TNF-α, TNF complex II, which consists of receptor-interacting protein 1, TNF receptor-associated protein with death domain, TNF receptor-associated factor 2, Fas-associated death domain protein, and pro-caspase-8, binds to the C-terminus of Romo1 located in the mitochondria. Concurrently, Romo1 recruits Bcl-X L to reduce the mitochondrial membrane potential, resulting in ROS production and apoptotic cell death. On the basis of these results, we suggest that Romo1 is a molecular bridge between TNF-α signaling and the mitochondria for ROS production that triggers TNF-α-mediated apoptosis, as well as a novel target in the development of anti-inflammatory agents that block the origin of ROS production.

Original languageEnglish
Pages (from-to)1420-1434
Number of pages15
JournalCell Death and Differentiation
Volume17
Issue number9
DOIs
Publication statusPublished - 2010 Sept

Bibliographical note

Funding Information:
Figure 8 Bcl-XL expression suppresses TNF-a-induced ROS production and cell death mediated by Romo1. (a, b) After HeLa cells were transfected with Bcl-XL for 36 h, cells were incubated with TNF-a and CHX for the indicated times. The cells were stained with CM-H2DCFDA for 30 min, and ROS generation was analyzed by flow cytometry. *P<0.05; ***P<0.001 versus vector by two-way ANOVA. Solid line, not treated with TNF-a plus CHX; Dotted line, treated with TNF-a plus CHX. (c) After HeLa cells were transfected with Romo1, Bcl-XL, or Romo1 and Bcl-XL for 36 h, the cells were observed under an optical microscope (top). The cells were counted by staining with trypan blue (bottom). The results represent the means (±S.E.) of three independent experiments performed in triplicate. **, ##P<0.01; ###P<0.001 by two-way ANOVA. (d) After HeLa cells were transfected with Romo1, Bcl-XL, or Romo1 and Bcl-XL, the cells were treated with TNF-a in the presence of CHX for the indicated times. The cells were observed under an optical microscope (top) and counted by staining with trypan blue (bottom). *P<0.05; **P<0.01 versus vector by two-way ANOVA. (e) After HeLa cells were transfected with Romo1 deletion mutants for 36 h, the cells were counted by staining with trypan blue. The results represent the means (±S.E.) of three independent experiments performed in triplicate. **, ##, ffP<0.01 versus zero time of each case by two-way ANOVA. Bar: 50 mm (the color reproduction of this figure is available on the html full text version of the manuscript) Acknowledgements. This work was supported by Grant FG06-2-20 from the 21st Century Frontier Functional Human Genome Project, funded by the Korean Government (MEST); a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A084537); by the Basic Science Research Program through the National Research Foundation (NRF), funded by the Ministry of Education, Science and Technology (R01-2006-000-10113-0); and by the NRF grant funded by the MEST (SRC program, No. R11-2005-017-04001-0).

Keywords

  • Bcl-X
  • ROS
  • Romo1
  • TNF-α
  • apoptosis
  • mitochondria

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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