The Fas/FasL apoptotic pathway is involved in kappa-opioid-induced apoptosis of human endometrial stromal cells.
Human endometrium expresses specific kappa-opioid binding sites and their endogenous ligands, the dynorphins. In neural crest-derived tissues, kappa-opioids affect apoptosis, a phenomenon of major significance in endometrial stroma physiology. Our hypothesis was that endometrial kappa-opioids may play a role in endometrial stromal cell apoptosis. Thus, we examined the effect of the synthetic kappa-opioid agonist, U69593, on the apoptotic rate of human endometrial stromal cells in primary culture. Apoptosis of endometrial stromal cells was elevated after 3 h exposure to 100 nmol/l U69593, and remained elevated for up to 3 days. This effect was dose-dependent and was reversed by the general opioid antagonist, naloxone, suggesting that it is mediated via opioid receptors. In parallel, semi-quantitative Western blot and flow cytometry analysis showed that U69593 caused a rapid but transient up-regulation of Fas protein, suggesting that its effect on apoptosis is mediated by activation of the Fas/FasL apoptotic pathway. Additionally, U69593 increased the content of the anti-apoptotic members of the Bcl-2 family of proteins, the Bcl-2 and Bcl-x(L), whereas it had no significant effect on the apoptosis-promoting homologues Bax, Bcl-x(S) and Bak. This implies that a transient survival mechanism is activated in stromal cells as a parallel rescue response to the apoptosis-inducing factor. In conclusion, our data suggest that endometrial opioid dynorphins may participate in the apoptotic processes related to endometrial tissue remodelling during early pregnancy or menstruation.
Chatzaki
E
E
Department of Pharmacology, School of Medicine, University of Crete, Heraklion GR-711 10, Crete, Greece.
Makrigiannakis
A
A
Margioris
A N
AN
Kouimtzoglou
E
E
Gravanis
A
A
D017209:Apoptosis / Q000187:drug effects; D044482:Benzeneacetamides; D002478:Cells, Cultured; D004717:Endometrium / Q000166:cytology* / Q000187:drug effects; D053222:Fas Ligand Protein; D005260:Female; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology; D017473:Receptors, Opioid, kappa / Q000819:agonists / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects; D019014:fas Receptor / Q000378:metabolism*
D044482:Benzeneacetamides; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; D019014:fas Receptor; C045444:U 69593