Amelioration of cataracts and proteolysis in cultured lenses by cysteine protease inhibitor E64

T. R. Shearer, M. Azuma, L. L. David, T. Murachi

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Cataracts were produced in cultured rat lenses by either 10 μM calcium, ionophore A23187, 25 μM sodium selenite, or 30 mM xylose. E64, an inhibitor of cysteine proteases, such as calpain (EC., reduced severity of cataract and proteolysis of crystallins when included at a 500 μM concentration in the culture medium along with cataractogenic agents. Calpain II enzyme activity and the amount of calpain antigen were decreased in the cytosol of cataractous lens. However, E64 caused an increase in the amount of an 80-kD calpain subunit associated with the ethyleneglycol-bis-(β-aminoethylether) tetraacetic acid/ethylenediaminetetraacetic acid-washed insoluble proteins when lenses were incubated with cataractous agents. These data indicate that E64 was at least partially effective in inhibiting lens calpain, and that activation of lens calpain may involve binding to the insoluble fraction. These results provide strong evidence for the activation of calpain in rodent cataracts and suggest testing inhibitors of calpain as anticataract drugs.

Original languageEnglish (US)
Pages (from-to)533-540
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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