Watch for ICE in neurodegeneration.

Neuronal death occurs naturally during brain development and is a common response to an external insult. Cell death, whose mechanisms are currently being elucidated, appears in three forms: necrosis, apoptosis and programmed cell death. Recently, attention has focused on a family of cysteine proteases whose prototype is interleukin-1 beta converting enzyme (ICE). ICE, essential for IL-1 beta production and, thus, critical to necrotic mechanisms, also plays a role in apoptosis mediated through the stimulation of the lymphocyte fas antigen. The absence of ICE expression in neurons makes ICE an unlikely direct participant in neuronal death. However, the existence of ICE family members in neurons combined with the pharmacological inhibition of both apoptosis in vitro and programmed cell death during development make ICE homologs candidates for mediating these two forms of cell death. Since several neurodegenerative diseases as well as at least one neurological disorder may have an apoptotic component, antagonists of this protease family may be neuroprotective.