Linked Life Data

10482394

Source:http://linkedlifedata.com/resource/pubmed/id/10482394

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1999-10-25
pubmed:abstractText
Human monocytic leukemia cells (U937) were challenged with synthetic melittin, and arachidonic acid (AA)/acylated lipids from both cells (pellet) and media (supernatant) were analyzed by thin layer chromatography (TLC). From these data, melittin-mediated activation/inhibition of major phospholipases in U937 cells was related to pore formation, permeabilization and cytolysis as determined by light microscopy. Also, the effect of melittin on acylhydrolase activity in the cell-free sonicated lysates of U937 cells was examined. Here we report that synthetic melittin (1 microM) caused cytolysis of U937 cells within 10-15 min. Cellular hypertrophy (5 min) and aggregation (1 min) preceded cytolysis. TLC analysis of these lipids showed that total levels (cellular + medium) of diacylglycerol (DAG), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) decreased, while that of arachidonic acid (AA) increased continuously (5-30 min). However, levels of phosphatidylethanol (PEt) phosphatidic acid (PA) and phosphatidylserine (PS) were increased transiently at 5-10 min being maximal at 5 min. Taken together, the combined levels of PEt and PA (an end product of phopholipase D, PLD) were about 42-fold higher than the level of AA at 5-10 min. Enhancement of AA levels appeared to result from in vitro reactions of various acylhydrolases and their phospholipid substrates (free/membrane bound) liberated into the medium during pore formation/cell lysis. Incubation of sonicated cell lysates also enhanced release of AA, which decreased upon addition of melittin, indicating that melittin inhibited these acylhydrolases. A consistent decrease in the level of DAG showed that phospholipase C was unaffected. Hence, transient activation of PLD bymelittin at the point of initiation of cytolysis, suggested a role for PLD in melittin-mediated membrane disruption/cytolysis by an uncharacterized signal transduction mechanism.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0041-0101
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1605-19
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Melittin activates endogenous phospholipase D during cytolysis of human monocytic leukemia cells.
pubmed:affiliation
Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555-1070, USA. sssaini@utmb.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.