Evidence of tumor necrosis factor receptor 1 signaling in human temporal lobe epilepsy

Exp Neurol. 2006 Dec;202(2):410-20. doi: 10.1016/j.expneurol.2006.07.003. Epub 2006 Aug 17.


Seizures, particularly when prolonged, may cause neuronal loss within vulnerable brain structures such as the hippocampus, in part by activating programmed (apoptotic) cell death pathways. Experimental modeling suggests that seizures activate tumor necrosis factor receptor 1 (TNFR1) and engage downstream pro- and anti-apoptotic signaling cascades. Whether such TNFR1-mediated signaling occurs in human temporal lobe epilepsy (TLE) is unknown. Presently, we examined this pathway in hippocampus surgically obtained from refractory TLE patients and contrasted findings to matched autopsy controls. Western blotting established that total protein levels of the TNFR1 proximal signaling adaptor TNFR-associated protein with death domain (TRADD), cleaved initiator caspase-8 and apoptosis signal-regulating kinase 1 (ASK1) were higher in TLE samples than controls. Intracellular distribution analyses revealed raised cytoplasmic levels of TNFR1, TRADD and the caspase-8 recruitment adaptor Fas-associated protein with death domain (FADD), and higher levels of TRADD and cleaved caspase-8 in the microsomal fraction, in TLE samples. Immunoprecipitation studies detected TRADD-FADD binding, and fluorescence microscopy revealed TRADD co-localization with FADD in TLE hippocampus. These data suggest that TNFR1 signaling is engaged in the hippocampus of patients with refractory temporal lobe epilepsy.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Blotting, Western / methods
  • Caspase 8 / metabolism
  • Epilepsy, Temporal Lobe / metabolism*
  • Epilepsy, Temporal Lobe / pathology
  • Female
  • Fluorescent Antibody Technique / methods
  • Humans
  • Indoles
  • MAP Kinase Kinase Kinase 5 / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Models, Biological
  • Postmortem Changes
  • Receptors, Tumor Necrosis Factor, Type I / metabolism*
  • Signal Transduction / physiology*
  • Subcellular Fractions / metabolism


  • Indoles
  • Receptors, Tumor Necrosis Factor, Type I
  • DAPI
  • MAP Kinase Kinase Kinase 5
  • Caspase 8