1. Retinoid-induced mu opioid receptor expression by phytohemagglutinin-stimulated U937 cells.
- Author
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Royal W 3rd, Leander MV, and Bissonnette R
- Subjects
- Cell Differentiation drug effects, Gene Expression Regulation drug effects, Humans, Polymerase Chain Reaction, Promoter Regions, Genetic drug effects, RNA, Messenger analysis, RNA, Messenger genetics, Receptors, Opioid, mu genetics, Receptors, Retinoic Acid antagonists & inhibitors, Retinoid X Receptors agonists, Retinoid X Receptors pharmacology, Signal Transduction drug effects, U937 Cells, Phytohemagglutinins pharmacology, Receptors, Opioid, mu metabolism
- Abstract
Opioid use may be associated with an increased risk of neurological disease in human immunodeficiency virus (HIV) infection through effects on immune cell function. Studies were performed to examine the effects of specific retinoid receptor activation on mu opioid receptor (MOR) production by phytohemagglutinin (PHA)-stimulated U937 cells, a mononuclear cell line. PHA stimulation increased activation of the MOR promoter as well as levels of MOR mRNA, total receptor protein in cell lysates, and surface and cytoplasmic receptor expression. Retinoid X receptor (RXR) agonist and retinoic acid receptor (RAR) antagonist further increased MOR expression by the PHA-stimulated cells. In contrast, MOR expression was suppressed by RAR agonist and by RXR antagonist. Finally, opioid receptor binding was also increased by RXR agonist and RXR antagonist; no increase in binding occurred in the presence of RAR agonists and RXR antagonist. All together, these studies suggest that MOR expression in U937 cells can be differentially regulated by specific retinoid receptor activation. Such effects may have important clinical relevance for opioid users with HIV infection, including individuals with neurological disease.
- Published
- 2005
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