Role of Ubiquitin Carboxy Terminal Hydrolase-L1 in Neural Cell Apoptosis Induced by Ischemic Retinal Injury in Vivo

Takayuki Harada, Chikako Harada, Yu Lai Wang, Hitoshi Osaka, Kazuhito Amanai, Kohichi Tanaka, Shuichi Takizawa, Rieko Setsuie, Mikako Sakurai, Yae Sato, Mami Noda, Keiji Wada

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69 Citations (Scopus)

Abstract

Ubiquitin is thought to be a stress protein that plays an important role in protecting cells under stress conditions; however, its precise role is unclear. Ubiquitin expression level is controlled by the balance of ubiquitinating and deubiquitinating enzymes. To investigate the function of deubiquitinating enzymes on ischemia-induced neural cell apoptosis in vivo, we analyzed gracile axonal dystrophy (gad) mice with an exon deletion for ubiquitin carboxy terminal hydrolase-L1 (UCH-L1), a neuron-specific deubiquitinating enzyme. In wild-type mouse retina, light stimuli and ischemic retinal injury induced strong ubiquitin expression in the inner retina, and its expression pattern was similar to that of UCH-L1. On the other hand, gad mice showed reduced ubiquitin induction after light stimuli and ischemia, whereas expression levels of antiapoptotic (Bcl-2 and XIAP) and prosurvival (brain-derived neurotrophic factor) proteins that are normally degraded by an ubiquitin-proteasome pathway were significantly higher. Consistently, ischemia-induced caspase activity and neural cell apoptosis were suppressed ∼70% in gad mice. These results demonstrate that UCH-L1 is involved in ubiquitin expression after stress stimuli, but excessive ubiquitin induction following ischemic injury may rather lead to neural cell apoptosis in vivo.

Original languageEnglish
Pages (from-to)59-64
Number of pages6
JournalAmerican Journal of Pathology
Volume164
Issue number1
DOIs
Publication statusPublished - Jan 2004

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All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine

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