Fig. 6.

S1P1 receptor contributes to high density lipoprotein-induced cell proliferation of mice adipose-derived stem cells. a Western blot confirms the presence of several classical receptors for high density lipoprotein (HDL) in mice adipose-derived stem cells (ADSCs). Human umbilical vein endothelial cells (EC) were used as a positive control to validate the result. Data show that only S1P1, a classical receptor for HDL, was expressed in mice ADSCs. b MTT assay and c bromodeoxyuridine (BrdU) assay show that the effect of HDL-promoting cell proliferation in mice ADSCs was blocked when pretreated with S1P1 receptor specific inhibitor VPC23019 for 30 minutes prior to 24 hours of HDL treatment. d Western blot change in expression of various signal pathway molecules and cell cycle regulatory proteins in mice ADSCs pretreated with S1P1 receptor inhibitor VPC23019 for 30 minutes prior to incubation with HDL for 1 hour. e p-Akt, f p-ERK, g cyclin D₁, h cyclin E, i p21, j p27. Results are the mean ± standard error of three experiments for each condition determined by densitometry relative to corresponding total protein/beta-actin. *P <0.05, **P <0.01, ***P <0.001