Role of acidic sphingomyelinase in thymol-mediated dendritic cell death

Mol Nutr Food Res. 2010 Dec;54(12):1833-41. doi: 10.1002/mnfr.200900577.

Abstract

Scope: Thymol is a component of several plants with antimicrobial activity. Little is known about the effects of thymol on immune cells of the host. This study addressed the effects of thymol on dendritic cells (DCs), regulators of innate and adaptive immunity.

Methods and results: Immunohistochemistry, Western blotting and fluorescence-activated cell sorting analysis were performed in bone marrow-derived DCs either from wild-type mice or from mice lacking acid sphingomyelinase (ASM⁻/⁻) treated and untreated for 24 h with thymol (2-100 μg/mL). Thymol treatment resulted in activation of ASM, stimulation of ceramide formation, downregulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, activation of caspase 3 and caspase 8, DNA fragmentation as well as cell membrane scrambling. The effects were dependent on the presence of ASM and were lacking in ASM⁻/⁻ mice or in wild-type DCs treated with sphingomyelinase inhibitor amitriptyline.

Conclusion: Thymol triggers suicidal DC death, an effect mediated by and requiring activation of ASM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Caspase 3 / metabolism
  • Caspase 8 / metabolism
  • Cell Death / drug effects*
  • Cells, Cultured
  • Ceramides / biosynthesis
  • DNA Fragmentation
  • Dendritic Cells / drug effects*
  • Dendritic Cells / enzymology
  • Down-Regulation
  • Flow Cytometry
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Sphingomyelin Phosphodiesterase / metabolism*
  • Thymol / pharmacology*
  • bcl-X Protein / metabolism

Substances

  • Bcl2l1 protein, mouse
  • Ceramides
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-X Protein
  • Thymol
  • Sphingomyelin Phosphodiesterase
  • Casp3 protein, mouse
  • Casp8 protein, mouse
  • Caspase 3
  • Caspase 8