Delta-opioid receptor activation promotes mesenchymal stem cell survival via PKC/STAT3 signaling pathway.
BACKGROUND
The survival of stem cells upon transplantation into ischemic myocardium is a major concern in cell-based therapy. In this study, we tested the hypothesis that activation of opioid receptors would enhance the survival of mesenchymal stem cells (MSCs) upon exposure to an injury stimulus.


RESULTS
MSCs were obtained from rat bone marrow and cultured in basal DMEM cell culture medium. Delta-opioid receptor (DOR) was present in MSCs as examined by reverse transcription-polymerase chain reaction and immunochemistry. Activation of DOR with 5µmol/L SNC80 (DOR agonist) for 24h significantly enhanced MSC viability upon exposure to 5µg/ml actinomycin D as determined by TUNEL and MTT assays. The cytoprotection was abolished with 20µmol/L naltrindole hydrochloride (a DOR antagonist). Treatment of the cells with 1.5µmol/L chelerythrine (protein kinase C inhibitor) and 1.25µmol/L WP1066 (signal transducer and activator of transcription 3 (STAT3) inhibitor) blocked SNC80-induced cytoprotection. Furthermore, treatment of the cells with chelerythrine also blocked STAT3-phosphorylation and Mcl-1 gene expression.


CONCLUSIONS
Taken together, the results indicate that DOR plays a critical role in MSC survival upon exposure to actinomycin D through activation of protein kinase C and its downstream signaling molecules STAT3 and Mcl-1. DOR may be a novel therapeutic target for stem cell survival during cell-based therapy.
Department of Pathology, University of Cincinnati, Cincinnati, OH 45267, USA.
Sayaka
S
Higuchi
Masaaki
M
Ii
Ping
P
Zhu
Muhammad
M
Ashraf
D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003609:Dactinomycin / Q000494:pharmacology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D023421:Models, Animal; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D017465:Receptors, Opioid, delta / Q000187:drug effects / Q000502:physiology*; D050796:STAT3 Transcription Factor / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D001549:Benzamides; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D010879:Piperazines; D019253:Proto-Oncogene Proteins c-bcl-2; D017465:Receptors, Opioid, delta; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; C088464:4-(alpha-(4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N,N-diethylbenzamide; D003609:Dactinomycin; D009271:Naltrexone; D011493:Protein Kinase C; C055382:naltrindole