[Back to Issue 3 ToC] [Back to Journal Contents] [Back to Biochemistry (Moscow) Home page]

A Secreted Caspase-3-Substrate-Cleaving Activity at Low pH Belongs to Cathepsin B: a Study on Primary Brain Cell Cultures

M. V. Onufriev1, A. A. Yakovlev1,2, A. A. Lyzhin3, M. Yu. Stepanichev1, L. G. Khaspekov3, and N. V. Gulyaeva1*

1Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, ul. Butlerova 5a, 117485 Moscow, Russia; fax: (495) 952-4007; E-mail: nata_gul@pisem.net

2Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, ul. Institutskaya 3, 142290 Pushchino, Moscow Region, Russia

3Neurology Research Center, Russian Academy of Medical Sciences, Volokolamskoe Shosse 80, 125367 Moscow, Russia

* To whom correspondence should be addressed.

Received June 11, 2008; Revision received August 5, 2008
The cysteine proteases caspase-3 and cathepsins are involved in both neuronal plasticity and neuropathology. Using primary neuroglial and glial cerebellar cultures, the pH dependence of cleavage of a synthetic caspase-3 substrate, Ac-DEVD-AMC, was studied. At acidic pH, cathepsin B cleaved Ac-DEVD, this activity being significantly higher than that of caspase-3 at pH 7.4. This activity is blocked by peptide inhibitors of both caspase-3 and cathepsin B. Substitution of culture medium for balanced salt solution stimulated cathepsin B secretion in both types of cultures. Ischemia (oxygen–glucose deprivation) significantly decreased secretion of cathepsin B activities into the culture medium.
KEY WORDS: cathepsin B, caspase-3, ischemia/reoxygenation, neurons, glia

DOI: 10.134/S0006297909030067