Activation by C5a of endothelial cell caspase 8 and cFLIP

Inflamm Res. 2009 Jan;58(1):30-7. doi: 10.1007/s00011-008-8156-9.


Objectives and design: In this study, we examine the relationship between C5a and activation of cysteine aspartic acid protease 8 (caspase 8) in human umbilical vein endothelial cells (HUVEC).

Materials or subjects: Primary cultures of HUVEC were used.

Treatments: Recombinant human C5a (50 ng/ml) was used in the presence or absence of 10 microg/ml cycloheximide (CHX).

Methods: HUVEC were treated with C5a alone and in the presence of CHX, then monitored for cell viability, poly- ADP-ribose 1 (PARP-1) and caspase 8 activities. Gene and protein expressions were assessed for caspase 8 and the caspase 8 homologue, FLICE -inhibitory protein (cFLIP).

Results: We found a 43.1 +/- 6.9 percent reduction in viability of HUVEC stimulated for 18 h with 50 ng/ml C5a in the presence of 10 microg/ml CHX (p < 0.05). In contrast, the cell viability of cells stimulated for 18 h with 50 ng/ml C5a or 10 microg/ml CHX alone was not significantly different compared to the non-stimulated control. Treatment of HUVEC with C5a induced an increase in caspase 8 activity but did not significantly affect cFLIP levels.

Conclusions: These data suggest caspase 8 activation induced by C5a leads to cell death if protein synthesis of antiapoptotic protein(s) is blocked.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • CASP8 and FADD-Like Apoptosis Regulating Protein / metabolism*
  • Caspase 8 / metabolism*
  • Cells, Cultured
  • Complement C5a / metabolism*
  • Cycloheximide / pharmacology
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Enzyme Activation
  • Humans
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases / metabolism


  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • Complement C5a
  • Cycloheximide
  • PARP1 protein, human
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases
  • Caspase 8