ABSTRACT
Increasing studies have demonstrated that interferon gamma (IFN-γ),which serves as a critical inflammatory cytokine,is essential to induce the immunosuppressive effects of mesenchymal stem cells (MSCs).However,the mechanisms underlying the enhanced immunosuppressive effects of IFN-γ-stimulated MSCs (γMSCs) are not fully understood.MSC-derived rnicrovesicles (MSC-MVs) have been viewed as potential pivotal mediators of the immunosuppressive effects of MSCs.Moreover,microRNAs (miRNAs) are important regulators of immunological processes and can be shuttled from cell to cell by MVs.The aim of our study was to analyze the the miRNA expression signature of MVs derived from γMSCs (γMSC-MVs),which may provide better understanding of the immunosuppressive property of their parent cells.Through miRNA microarray and bioinformatics analysis,we found 62 significantly differentially expressed miRNAs (DEMs) in γMSC-MVs compared with MSC-MVs.And the potential target genes and signaling pathways regulated by DEMs were predicted and analyzed.Interestingly,many DEMs and predicted signaling pathways had been.demonstrated to be involved in immunoregulation.Furthermore,the network between immunoregulation-related pathways and relevant DEMs was constructed.Collectively,our research on the miRNA repertoires of γMSC-MVs not only provides new perspectives into the mechanisms underlying the enhanced immunosuppressive property of γMSCs,but also paves the way to clinical application of these potent organelles in the future.
ABSTRACT
P-450-dependent epoxygenase pathway of arachidonic acid and the products of epoxyeicosatrienoic acids (EETs) have been demonstrated to be involved in angiogenesis and tumor progression.This study examined the expression of EETs and the role of the pathway in the angiogenesis of multiple myeloma (MM).MM cell lines of U266 and RPMI8226 were cultured,and the EETs levels (11,12-EET and 14,15-EET) in the supematant were determined by ELISA.Human umbilical vein endothelial cells (HUVECs) were cultured and used for analysis of the angiogenesis activity of the two MM cell lines,which was examined both in vitro and in vivo by employing MTT,chemotaxis,tube formation and matrigel plug assays.11,12-EET and 14,15-EET were found in the supematant of the cultured MM cells.The levels of the two EETs in the supernatant of U266 cells were significantly higher than those in the RPMI8226 cell supematant (P＜0.05),and the levels paralleled the respective angiogenesis activity of the two different MM cell lines.17-octadecynoic acid (17-ODYA),as a specific inhibitor of P450 enzyme,suppressed HUVECs proliferation and tube formation induced by MM cells.Furthermore,17-ODYA decreased the EET levels in the supernatant of MM cells.These results suggest that EETs may play an important role in the angiogenesis of MM,and the inhibitor 17-ODYA suppresses this effect.
ABSTRACT
Summary: The inhibitory effects ofparthenolide (PTL) on angiogenesis induced by multiple myeloma (MM) cells in vitro, and the mechanism were investigated. Human MM line RPMI8226 cells were cultured in vitro. The effects of MM culture supernatant on the migration and tubule formation ability of human umbilical vein endothelial cells (HUVECs) treated with PTL were observed. By using Western blot, the expression of p65 and IκB-α in MM cells was detected. RT-PCR was used to assay the expression of VEGF, IL-6, MMP2 and MMP9 mRNA in MM cells. ELISA was used to measure the levels of VEGF and IL-6 in MM cell culture supernatant. The expression of MMP2 and MMP9 in MM cells was examined by immunohistochemistry. (1) In 3.5, 5.0, 7.5 and 10 μmol/L PTL groups the number of migrated cells was 310±56, 207±28, 127±21 and 49±10 respectively, which was significantly different from that in positive control group (598±47) (P<0.01). In 3.5 and 5.0 μmol/L PTL groups the areas of capillary-like structures were 0.092±0.003 and 0.063±0.002 mm2, significantly less than in positive control group (0.262±0.012 mm2) (P<0.01), but in 7.5 and 10 μmol/L PTL groups no capillary-like structures were found;(2) After treatment with different concentrations of PTL for 48 h, the expression of p65 protein was gradually decreased, while that of IκB-α was gradually enhanced with the increased concentration of PTL;(3) After treatment with 3.5,5.0, 7.5 and 10 μmol/L PTL for 48 h, the VEGF levels in the supematant were 2373.4±392.2,1982.3±293.3, 1247.0±338.4 and 936.5±168.5 pg/mL respectively, significantly different from those in positive control group (2729±440.0 pg/mL) (P<0.05). After treatment with 7.5 and 10 μmol/L PTL, the IL-6 levels in the culture supernatant were 59.6±2.8 and 41.4±9.8 pg/mL respectively, significantly lower than in positive control group (1287.3±43.5 pg/mL) (P<0.05);(4) RT-PCR revealed that PTL could significantly inhibit the expression of VEGF and IL-6 mRNA in MM cells, but not influence the expression of MMP2 and MMP9 mRNA.;(5) Immunohisto chemistry indicated that PTL had no significant effects on the expression of MMP2 and MMP9 protein in MM cells. It was concluded that the abilities of the culture supematant of MM cells treated with PTL to induce endothelial cells migration and tubule formation were significantly reduced, suggesting PTL could obviously inhibit the angiogenesis induced by MM cells. PTL could decrease NF-kappaB activity and significantly suppress the expression of VEGF and IL-6 mRNA and protein, which might contribute to the mechanism by which PTL inhibited the angiogenesis induced by MM cells.