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Calpain secreted by activated human lymphoid cells degrades myelin
Author(s) -
Deshpande R. V.,
Goust J. M.,
Hogan E. L.,
Banik N. L.
Publication year - 1995
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490420214
Subject(s) - calpain , calpastatin , myelin , myelin basic protein , egta , biochemistry , extracellular , microbiology and biotechnology , antigen , biology , chemistry , enzyme , calcium , immunology , central nervous system , organic chemistry , neuroscience
Calpain secreted by lymphoid (MOLT‐3, M.R.) or monocytic (U‐937, THP‐1) cell lines activated with PMA and A23187 degraded myelin antigens. The degradative effect of enzymes released in the extracellular medium was tested on purified myelin basic protein and rat central nervous system myelin in vitro. The extent of protein degradation was determined by SDS‐PAGE and densitometric analysis. Various proteinase inhibitors were used to determine to what extent protein degradation was mediated by calpain and/or other enzymes. Lysosomal and serine proteinase inhibitors inhibited 20‐40% of the myelindegradative activity found in the incubation media of cell lines, whereas the calcium chelator (EGTA), the calpain‐specific inhibitor (calpastatin), and a monoclonal antibody to m calpain blocked myelin degradation by 60‐80%. Since breakdown products of MBP generated by calpain may include fragments with antigenic epitopes, this enzyme may play an important role in the initiation of immune‐mediated demyelination. © 1995 Wiley‐Liss, Inc.