Critical role of calpain in axonal damage-induced retinal ganglion cell death

Morin Ryu, Masayuki Yasuda, Dong Shi, Ahmed Y. Shanab, Ryou Watanabe, Noriko Himori, Kazuko Omodaka, Yu Yokoyama, Jiro Takano, Takaomi Saido, Toru Nakazawa

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

Calpain, an intracellular cysteine protease, has been widely reported to be involved in neuronal cell death. The purpose of this study is to investigate the role of calpain activation in axonal damage-induced retinal ganglion cell (RGC) death. Twelve-week-old male calpstatin (an endogenous calpain inhibitor) knockout mice (CAST KO) and wild-type (WT) mice were used in this study. Axonal damage was induced by optic nerve crush (NC) or tubulin destruction induced by leaving a gelatin sponge soaked with vinblastine (VB), a microtubule disassembly chemical, around the optic nerve. Calpain activation was assessed by immunoblot analysis, which indirectly quantified the cleaved α-fodrin, a substrate of calpain. RGCs were retrogradely labeled by injecting a fluorescent tracer, Fluoro-Gold (FG), and the retinas were harvested and flat-mounted retinas prepared. The densities of FG-labeled RGCs harvested from the WT and CAST KO groups were assessed and compared. Additionally, a calpain inhibitor (SNJ-1945, 100 mg/kg/day) was administered orally, and the density of surviving RGCs was compared with that of the vehicle control group. The mean density of surviving RGCs in the CAST KO group was significantly lower than that observed in the WT group, both in NC and in VB. The mean density of surviving RGCs in the SNJ-1945-treated group was significantly higher than that of the control group. The calpain inhibitor SNJ-1945 has a neuroprotective effect against axonal damage-induced RGC death. This pathway may be an important therapeutic target for preventing this axonal damage-induced RGC death, including glaucoma and diabetic optic neuropathy and other CNS diseases that share a common etiology.

Original languageEnglish
Pages (from-to)802-815
Number of pages14
JournalJournal of Neuroscience Research
Volume90
Issue number4
DOIs
Publication statusPublished - 2012 Apr

Keywords

  • Axonal damage
  • Calpastatin
  • Glaucoma
  • Neuroprotection
  • SNJ1945

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience

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