Linked Life Data

15056807

Source:http://linkedlifedata.com/resource/pubmed/id/15056807

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-6-9
pubmed:abstractText
Past studies in our laboratory have shown that silica (-quartz) particle exposure of a mouse alveolar macrophage cell line (MH-S) elicits mitochondrial depolarization and caspase 3 and 9 activation, contributing to apoptosis. However, cellular pathways leading to these outcomes have not been extensively investigated. Initial studies revealed that silica exposure elicits lysosomal permeability after 1 h, as evidenced by leakage of FITC-conjugated dextran and acridine orange. We next evaluated a role for the lysosomal acidic compartment in apoptosis. Cells pretreated with the lysosomotropic weak base ammonium chloride, to increase lysosomal pH, showed decreased caspase activation and apoptotic DNA fragmentation. MH-S cells pretreated with pepstatin A, an inhibitor of lysosomal cathepsin D, showed decreased caspase 9 and 3 activation as well as a decreased percentage of cells that became apoptotic. DNA fragmentation and caspase 9 and 3 activation were also decreased in cells pretreated with despiramine, an inhibitor of lysosomal acidic sphingomyelinase. Silica pretreated with aluminum lactate (to blunt surface active sites) reduced caspase activation and apoptosis. Although aluminum lactate-treated silica still induced lysosomal permeability (by FITC-dextran leakage), one measure of lysosome integrity and function suggested a reduction in the extent and/or nature of lysosomal injury (by acridine orange retention). A role for reactive oxygen species (ROS) was investigated to explore another pathway for silica-induced apoptosis in addition to lysosomal enzymes; however, no role for ROS was apparent. Thus, following silica exposure, lysosomal injury precedes apoptosis, and the apoptotic signaling pathway includes cathepsin D and acidic sphingomyelinase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1096-6080
pubmed:author
pubmed:issnType
Print
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
34-48
pubmed:dateRevised
2010-9-17
pubmed:meshHeading
pubmed-meshheading:15056807-Aluminum Compounds, pubmed-meshheading:15056807-Animals, pubmed-meshheading:15056807-Antioxidants, pubmed-meshheading:15056807-Apoptosis, pubmed-meshheading:15056807-Blotting, Western, pubmed-meshheading:15056807-Caspases, pubmed-meshheading:15056807-Cathepsin D, pubmed-meshheading:15056807-Cell Line, pubmed-meshheading:15056807-DNA Fragmentation, pubmed-meshheading:15056807-Flow Cytometry, pubmed-meshheading:15056807-Hydrogen-Ion Concentration, pubmed-meshheading:15056807-Lactates, pubmed-meshheading:15056807-Lysosomes, pubmed-meshheading:15056807-Macrophages, Alveolar, pubmed-meshheading:15056807-Mice, pubmed-meshheading:15056807-Microscopy, Interference, pubmed-meshheading:15056807-Mitochondria, pubmed-meshheading:15056807-Reactive Oxygen Species, pubmed-meshheading:15056807-Silicon Dioxide, pubmed-meshheading:15056807-Sphingomyelin Phosphodiesterase
pubmed:year
2004
pubmed:articleTitle
Silica-induced apoptosis in mouse alveolar macrophages is initiated by lysosomal enzyme activity.
pubmed:affiliation
Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural