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Release of TNF-α from macrophages is mediated by small GTPase Rab37

Ryoichi Mori1, Kazuya Ikematsu, Tetsuya Kitaguchi

  • 1Department of Investigative Pathology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. ryoichi@nagasaki-u.ac.jp

European Journal of Immunology
|August 2, 2011
PubMed

Insights

Rab37 controls TNF-α secretion from macrophages during skin wound healing. This small GTPase interacts with Munc13-1 to regulate cytokine release, a key process in tissue repair.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • Activated macrophages release cytokines crucial for skin wound healing.
  • The precise molecular mechanisms governing cytokine secretion from macrophages remain unclear.

Purpose of the Study:

  • To elucidate the molecular mechanisms controlling cytokine secretion from macrophages during skin wound healing.
  • To investigate the role of small GTPase Rab isoforms, specifically Rab37, in TNF-α secretion.

Main Methods:

  • RT-PCR analysis of Rab isoform expression at wound sites.
  • Gene expression analysis of Rab37 in macrophages stimulated with LPS.
  • Overexpression and knockdown studies of Rab37 and Munc13-1 in RAW264.7 cells.
  • Liquid chromatography/mass spectrometry (LC-MS/MS) to identify Rab37-interacting proteins.
  • Immunocytochemical analysis to visualize protein and vesicle colocalization.

Main Results:

  • Six Rab isoforms (Rab3B, Rab27B, Rab30, Rab33A, Rab37, Rab40C) were upregulated during skin repair.
  • Rab37 gene expression was induced by LPS in macrophages.
  • Rab37 overexpression increased TNF-α secretion; Rab37 knockdown decreased it.
  • Munc13-1 was identified as a Rab37-interacting protein involved in membrane fusion.
  • Rab37 and Munc13-1 colocalized with TNF-α vesicles in activated macrophages.
  • Munc13-1 knockdown reduced TNF-α secretion.

Conclusions:

  • Rab37 plays a significant role in regulating TNF-α secretion from activated macrophages.
  • Rab37 interacts with Munc13-1 to control the release of TNF-α-containing vesicles.
  • These findings reveal a novel molecular mechanism for cytokine secretion in macrophage-mediated skin wound healing.

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