Browsing by Author "Wu, Xin"

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    Cloning and expression of a rat brain interleukin-1beta-converting enzyme (ICE)-related protease (IRP) and its possible role in apoptosis of cultured cerebellar granule neurons
    (Society for Neuroscience, 1997-03-01) Ni, Binhui; Wu, Xin; Du, Yansheng; Su, Yuan; Hamilton-Byrd, Elizabeth; Rockey, Pamela K.; Rosteck, Paul, Jr.; Poirier, Guy G.; Paul, Steven M.; Pharmacology and Toxicology, School of Medicine
    Several members of the IL-1beta-converting enzyme (ICE) family of proteases recently have been implicated in the intracellular cascade mediating the apoptotic death of various cell types. It is unclear, however, whether ICE-related proteases are involved in apoptosis of mammalian neurons and, if so, how they are activated. Here we report the cloning of an ICE-related protease (IRP) from rat brain, which displays strong sequence identity to human CPP32. In situ hybridization histochemistry reveals that this IRP mRNA is expressed in neuron-enriched regions of the developing and adult rat brain but is profoundly downregulated in the adult (compared with developing) brain. To investigate whether this IRP is involved in the death of neurons in the developing brain, we studied IRP expression in cultured cerebellar granule neurons. In cultured cerebellar granule neurons, reduction of extracellular K+ reliably induces apoptosis and stimulates overexpression of IRP mRNA. The latter is especially prominent 4 hr after switching from high K+ to low K+ medium. The expression of IRP mRNA was maintained at this level for at least 8 hr and was followed by apoptotic death of these neurons. Induction of IRP mRNA and cell death are blocked completely by adding depolarizing concentrations of K+