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Evaluation of Caspase Activation to Assess Innate Immune Cell Death
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Differential effects of caspase inhibitors on TNF-induced necroptosis

Hirofumi Sawai1

  • 1Department of Internal Medicine, Osaka Dental University, 8-1 Kuzuhahanazonocho, Hirakata, Osaka 573-1121, Japan. sawai@cc.osaka-dent.ac.jp

Biochemical and Biophysical Research Communications
|February 16, 2013
PubMed

Insights

Tumor necrosis factor (TNF) can induce necroptosis with caspase inhibitors. Z-DEVD-fmk induced necroptosis, while Z-Asp-CH2-DCB did not, suggesting Z-Asp-CH2-DCB is a specific caspase-3 inhibitor.

Area of Science:

  • Cellular biology
  • Molecular mechanisms of cell death
  • Apoptosis and necroptosis pathways

Background:

  • Tumor necrosis factor (TNF) is known to trigger necroptosis, a form of programmed cell death, particularly when caspases are inhibited.
  • The specificity of various caspase inhibitors in modulating TNF-induced cell death pathways requires further investigation.

Purpose of the Study:

  • To investigate whether caspase inhibitors other than Z-VAD-fmk can induce TNF-mediated necroptosis.
  • To determine the specificity of Z-DEVD-fmk and Z-Asp-CH2-DCB in inhibiting different caspases during TNF signaling.

Main Methods:

  • Treatment of cells with TNF in the presence of different caspase inhibitors (Z-VAD-fmk, Z-DEVD-fmk, Z-Asp-CH2-DCB).
  • Assessment of necroptosis induction.
  • Analysis of caspase-3 and caspase-8 activation and cleavage.
  • Evaluation of RIP1 cleavage and degradation.

Main Results:

  • TNF-induced necroptosis was observed with Z-VAD-fmk and Z-DEVD-fmk, but not with Z-Asp-CH2-DCB.
  • Z-Asp-CH2-DCB, unlike Z-DEVD-fmk, allowed partial proteolysis of procaspase-3 and procaspase-8.
  • Partial RIP1 degradation was observed with Z-Asp-CH2-DCB, contrasting with complete inhibition by Z-VAD-fmk and Z-DEVD-fmk.

Conclusions:

  • Partial caspase-8 activation by Z-Asp-CH2-DCB may suppress TNF-induced necroptosis through RIP1 cleavage.
  • Z-Asp-CH2-DCB functions as a caspase-3-specific inhibitor, whereas Z-DEVD-fmk does not in this context.

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