Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2003-10-21
pubmed:abstractText
Activation of the aryl hydrocarbon receptor (AHR), a basic helix-loop-helix transcription factor, in lymphocytes by the immunosuppressive environmental contaminant 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD) has been shown to cause thymic atrophy in every species studied. We set out to identify the specific hemopoietic cellular populations in which the AHR was activated to lead to thymic atrophy and to determine the effect of AHR activation in those cellular populations. Initially, we examined whether AHR activation in intrathymic dendritic cells could mediate TCDD-induced thymic atrophy. It was found that thymic atrophy occurred only when the AHR could be activated in the thymocytes but not hemopoietic-derived dendritic cells or other APCs. We next analyzed the effect of TCDD on the proliferation of thymocytes in vivo. There was a significant increase in the percentage of thymocytes in the G(1) phase of the cell cycle and a significant decrease in the percentage of S plus G(2)/M thymocytes, especially in the CD4(-)CD8(-)CD3(-) triple-negative intrathymic progenitor cell population 24 h after exposure to 30 micro g/kg TCDD. Furthermore, by 12 h after exposure to TCDD, we observed approximately 60% reduction of 5-bromo-2'-deoxyuridine incorporation in specific intrathymic progenitor cell populations. This reduction persisted for at least 6 days. These data indicate that intrathymic progenitor cells are direct targets of TCDD in the thymus and suggest that TCDD causes thymic atrophy by reducing entrance into cell cycle in these populations.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
171
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4582-91
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Cell proliferation arrest within intrathymic lymphocyte progenitor cells causes thymic atrophy mediated by the aryl hydrocarbon receptor.
pubmed:affiliation
Department of Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't