[Role of sphingosine 1-phosphate receptor signaling in hematopoietic stem/progenitor cell transmigration].
OBJECTIVE
To determine the role of sphingosine 1-phosphate receptor (S1PRs ) signaling in CD34+ hematopoietic stem/progenitor cell transmigration.


METHODS
CD34(+) cells were separated by Ficoll density gradient centrifugation and incubated in DMEM medium with 10% fetal calf serum. The cells were pretreated by FTY720, with or without pertussis toxin (PTX) and antiCXCR4 mAb in the medium, followed by addition of 100 ng/ml SDF-1 into the lower chamber of a Costar 24-well transwell. The migrated cells were counted using FACS and the migrating rates were determined. The expressions of sphingosine 1-phosphate receptors were analyzed in CD34(+) cells before and after the transmigration by reverse transcriptase- polymerase chain reaction (RT-PCR). Cord blood CD34(+) cells were treated with or without FTY720 (10(+) mol/L), and the expressions of CD49d (VLA-4), CD11a (LFA-1), and CD62L (L-selectin) were analyzed at 1, 8, and 16 h after the treatment.


RESULTS
While FTY720 did not affect spontaneous migration, a substantial increase of SDF-1-induced transmigration was observed in the presence of FTY720 (15.26 2.14 to 28.64 2.37). The FTY720-enhanced transmigration was completely blocked by addition of PTX or antiCXCR4 mAb. S1p1-5 was expressed in fresh isolated cord blood CD34(+) cells. The migrating cells stimulated by FTY720 and SDF-1 only expressed S1P1, S1P3, and S1P4. The expressions of CD49d, CD11a and CD62L on CD34(+) cells treated with FTY720 remained unchanged at the selected time points as compared with the control.


CONCLUSIONS
S1PRs are involved the transmigration of CD34(+) cells. The activation of S1PRs results in increased chemotactic response of CD34(+) to SDF-1. These effects are mediated through CXCR4 and PTX-sensitive Gi proteins. Only the CD34(+) cells expressing the specific receptors can rapidly transmigrate. The activation of the S1PRs does not affect the expressions of the adhesion molecules on cord blood CD34(+) cells.
Second Affiliated Hospital of Guangzhou Medical College, Guangzhou Institute of Cardiovascular Diseases, Guangzhou, China. owenc@126.com
Wen-chao
WC
Ou
Shi-ming
SM
Liu
Long-geng
LG
Xiong
Guo-qing
GQ
Li
Meng-qun
MQ
Tan
D018952:Antigens, CD34 / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D000068876:Fingolimod Hydrochloride; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D011409:Propylene Glycols / Q000494:pharmacology; D049349:Receptors, Lysosphingolipid / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000081025:Sphingosine-1-Phosphate Receptors
D018952:Antigens, CD34; D054377:Chemokine CXCL12; D011409:Propylene Glycols; D049349:Receptors, Lysosphingolipid; C477362:S1PR1 protein, human; D000081025:Sphingosine-1-Phosphate Receptors; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine