Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
2005-6-6
pubmed:abstractText
Helicobacter pylori infection causes chronic inflammation of the gastric mucosa that results from an ineffective immune response. We have demonstrated that one underlying mechanism is induction of macrophage apoptosis mediated by polyamines. The transcription factor c-Myc has been linked to induction of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis. We determined whether H. pylori stimulates transcriptional activation of ODC in macrophages, whether this occurs via c-Myc, and whether these events regulate activation of apoptosis. H. pylori induced a significant increase in ODC promoter activity that peaked at 6 h after stimulation and was closely paralleled by similar increases in ODC mRNA, protein, and enzyme activity. By 2 h after stimulation, c-Myc mRNA and protein expression was induced, protein was translocated to the nucleus, and there was specific binding of a consensus probe for c-Myc to nuclear extracts. Both an antennapedia-linked inhibitor of c-Myc binding (Int-H1-S6A,F8A) and transfection of a c-Myc dominant-negative construct significantly attenuated H. pylori-induced ODC promoter activity, mRNA, enzyme activity, and apoptosis in parallel. Transfection of ODC small interfering RNA inhibited ODC activity and apoptosis to the same degree as inhibition of c-Myc binding. These studies indicate that c-Myc is an important mediator of macrophage activation and may contribute to the mucosal inflammatory response to pathogens such as H. pylori by its effect on ODC.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22492-6
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:15843384-Active Transport, Cell Nucleus, pubmed-meshheading:15843384-Animals, pubmed-meshheading:15843384-Apoptosis, pubmed-meshheading:15843384-Cell Line, pubmed-meshheading:15843384-Enzyme Activation, pubmed-meshheading:15843384-Genes, Dominant, pubmed-meshheading:15843384-Helicobacter pylori, pubmed-meshheading:15843384-Immunoblotting, pubmed-meshheading:15843384-Luciferases, pubmed-meshheading:15843384-Macrophages, pubmed-meshheading:15843384-Mice, pubmed-meshheading:15843384-Ornithine Decarboxylase, pubmed-meshheading:15843384-Polyamines, pubmed-meshheading:15843384-Promoter Regions, Genetic, pubmed-meshheading:15843384-Protein Binding, pubmed-meshheading:15843384-Protein Transport, pubmed-meshheading:15843384-Proto-Oncogene Proteins c-myc, pubmed-meshheading:15843384-RNA, Messenger, pubmed-meshheading:15843384-RNA, Small Interfering, pubmed-meshheading:15843384-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:15843384-Time Factors, pubmed-meshheading:15843384-Transcriptional Activation, pubmed-meshheading:15843384-Transfection
pubmed:year
2005
pubmed:articleTitle
Helicobacter pylori-induced macrophage apoptosis requires activation of ornithine decarboxylase by c-Myc.
pubmed:affiliation
Department of Medicine, Division of Gastroenterology, and Greenebaum Cancer Center, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, MD 21201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural