BACKGROUNDThe sphingosine 1-phosphate (S1P) receptors (S1PRs) are a group of G protein-coupled receptors expressed on the surface of lymphocytes. The interaction between S1P and S1PRs plays a significant role in the migration and distribution of lymphocytes.

OBJECTIVETo investigate the influence of S1PR5 defect on the lymphocytes distribution in mice.

METHODSThe distribution of different subsets of lymphocyte in the mice with S1PR5 defect was examined by flow cytometry.

RESULTSCompared with wild type mice, the number of NK cells in the peripheral blood (PB) and spleen (SP) from the mice with S1PR5 defect decreased very significantly 〔PB: 6.4±0.45% vs 2.2±0.47(P<0.01,n=3)；SP: 3.0±0.91% vs 0.68±0.14%(P<0.05,n=3)〕. However, the NK cell number in the bone marrow (BM) and lymphonodes (LN) of the mice with S1PR5 defect increased very significantly 〔BM: 0.97±0.20 % vs 2.6±0.35% (P<0.01, n=3); LN: 0.35±0.16% vs 1.7±0.15% (P<0.01, n=3)〕. The percentages of CD3(+) lymphocyte in peripheral blood, spleen and lymph node were not statistically significantly different between these 2 types of mice 〔PB: 17.3±7.9% vs 17.0±4.6% (P>0.05, n=3); SP: 33.0±6.0% vs 27.4±1.8% (P>0.05, n=3); LN: 42.3±10.7% vs 51.2±2.7% (P>0.05, n=3)〕.

CONCLUSIONS1PR5 defect can significantly influence the NK cell distribution.

Animals ; Bone Marrow ; Cell Count ; Flow Cytometry ; Lymphocytes ; Lysophospholipids ; Mice ; Receptors, Lysosphingolipid ; Sphingosine ; analogs & derivatives

Sphingosine-1-phosphate (S1P) has been demonstrated to be a mediator and marker of heart diseases. We hypothesized that the expression of S1P receptors is involved in the S1P-mediated cardioprotection in vivo and may serve as a biomarker of ischemic heart disease. In vivo models of myocardial ischemia (MI) and ischemia-reperfusion (IR) were established by ligation of the left anterior descending artery (LAD) of rat heart, the mRNA expressions of S1PR1-3 were detected using real time PCR at different time intervals after ischemia (LAD for 15 min, 30 min, and 1 h) and IR. The results showed that mRNA expression of S1PR3, but not S1PR1 and S1PR2, increased greatly after IR. No statistical difference was found in any of the three S1P receptors after MI within 1 h. Regarding the studies of lipid concentration changes in myocardiopathy, we conclude that S1P receptors are not early response biomarkers for MI. There are different mechanisms when S1P plays a protection role in heart during MI and IR. The cooperation of lipid content and S1P receptor expression appears to form a regulation network during MI and IR.
Animals ; Lysophospholipids ; physiology ; Myocardial Reperfusion Injury ; physiopathology ; Rats ; Receptors, Lysosphingolipid ; physiology ; Sphingosine ; analogs & derivatives ; physiology

AIMTo establish the methods for determining the activity of sphingosine kinase(SPK) and the content of sphingosine 1-phosphate (S1P) in biological samples.

METHODSThe ECV304 cells were transfected with pcDNA3 vector encoding Flag-labeled SPK gene. The expression of SPK was measured by Western blot assay and the activity of SPK was determined by enzymatic reaction, isotope incorporation and thin-layer chromatography methods. The S1P in biological samples was extracted, digested by alkaline phosphatase and then catalyzed by SPK. The S1P contents were determined according to the amounts of products.

RESULTSSPK gene transfection could enhance the expression and activity of SPK in cells markedly, and the cellular S1P was also increased obviously. HGF stimulation could increase the activity of SPK and cellular S1P in ECV304 cells.

CONCLUSIONMethods for determining the activity of SPK and the content of SPK in biological samples were established.

Cell Line ; Cytophotometry ; Humans ; Isotope Labeling ; Lysophospholipids ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Sphingosine ; analogs & derivatives ; metabolism

Sphingosine 1-phosphate (S1P), which can be impacted by different growth factors through sphingosine kinase (SphK), is a bioactive lipid produced by metabolism of sphingolipid with various biological responses. Recombinant human granulocyte-colony-stimulating factor (rhG-CSF) have been used widely in peripheral blood stem/progenitor cell mobilization. This study was aimed to investigate the effects of rhG-CSF on S1P concentration in plasma of donors. The peripheral blood mononuclear cells and blood plasma were collected from 8 peripheral blood progenitor cell donors before mobilization and on the fifth day of mobilization with rhG-CSF. The SphK mRNA expression of blood mononuclear cells were detected by RT-PCR. The changes of S1P concentration were assayed with SphK enzyme catalyzed reaction. The results showed that both kinds blood mononuclear cells collected before and after rhG-CSF mobilization expressed SphK mRNA. The S1P concentration is low in donor's plasma both before and after mobilization with rhG-CSF, and there was no markedly change of S1P concentration in plasma before and after mobilization (P > 0.05). In conclusion, mobilization with rhG-CSF does not impact S1P concentration in donors' plasma.
Blood Donors ; Granulocyte Colony-Stimulating Factor ; therapeutic use ; Hematopoietic Stem Cell Mobilization ; Humans ; Lysophospholipids ; blood ; RNA, Messenger ; blood ; Recombinant Proteins ; Sphingosine ; analogs & derivatives ; blood

OBJECTIVETo investigate the effects of FTY720, a new immunosuppressive agent, on apoptosis and autophagy in multiple myeloma(MM) cell line U266 and to clarify its molecular mechanism.

METHODSU266 cells were treated with 0, 2.5, 5.0, 10.0 and 20.0 µmol/L FTY720 for 24 hours, and the cell viability was assayed by CCK-8 method. Then U266 cells were treated with 20.0 µmol/L FTY720 for 0, 2, 6 and 24 hours, the cell viability was tested. The apoptotic rates induced by different doses and time points of FTY720 were tested by flow cytometry separately. The expression of LC3B was detected by Western blot after U266 cells treated with different doses of FTY720 to see autophagy. U266 cells were treated with FTY720 ± Bafilomycin A1, an inhibitor of autophagy, for 24 hours, then the cell viability and apoptotic rates were tested. Meanwhile the expression of survivin, anti-apoptotic factors, were tested by Western blot.

RESULTSThe cell viability and the apoptotic rates were inhibited significantly by FTY720 (P < 0.05) in time-dependent and dose-dependent manner. The expression of LC3B-II increased significantly in a dose-dependent manner, it indicated that the autophagy was induced by FTY720. Bafilomycin A1 could rescue the cell viability and apoptotic rates in U266 cells treated with FTY720, and it could also rescue the expression of survivin decreased by FTY720.

CONCLUSIONSFTY720 can cause apoptosis and autophagy of U266 cells. The autophagy promote the apoptosis, which maybe due to the degradation of anti-apoptotic factors such as survivin or their upstream factors in lysosomes through autophagy.

Apoptosis ; drug effects ; Autophagy ; drug effects ; Cell Line, Tumor ; Fingolimod Hydrochloride ; Humans ; Multiple Myeloma ; pathology ; Propylene Glycols ; pharmacology ; Sphingosine ; analogs & derivatives ; pharmacology

Action Potentials ; drug effects ; physiology ; Animals ; Guinea Pigs ; Heart Ventricles ; drug effects ; Lysophospholipids ; pharmacology ; Myocardial Contraction ; drug effects ; physiology ; Myocardium ; Sphingosine ; analogs & derivatives ; pharmacology

This study is to investigate the effects of ceramide on GSTA1 expression in Caco-2 cells. After being exposed to ceramide for a fixed time, GSTA1 protein expression was detected by Western blotting analysis; GSTA1 mRNA expression was detected by real time PCR; dual luciferase assay was used to analyze GSTA1 transcriptional activity and GSTA1 activity was determined toward androstanedione (AD) as substrate. The data showed that ceramide can significantly induce the expression of protein and GSTA1 mRNA, and increase transcriptional activity and enzyme activity of GSTA1. The results demonstrated that ceramide may increase resistance to chemotherapeutics in Caco-2 cells by up-regulating the expression of GSTA1.
Caco-2 Cells ; Enzyme Activation ; drug effects ; Glutathione Transferase ; genetics ; metabolism ; Humans ; RNA, Messenger ; metabolism ; Sphingosine ; analogs & derivatives ; pharmacology ; Transcriptional Activation ; drug effects ; Up-Regulation

OBJECTIVEDiabetic nephropathy (DN) is the major cause of end-stage renal disease worldwide and its prevalence continues to increase. Currently, therapies for DN provide only partial renoprotection; hence new targets for therapeutic intervention need to be identified. In this review, we summarized the new target, sphingosine kinase-1/sphingosine 1-phosphate (SphK1/S1P) pathway, explored its potential therapeutic role in the prevention and treatment of DN.

DATA SOURCESMost relevant articles were mainly identified by searching PubMed in English.

STUDY SELECTIONMainly original articles and critical review articles by major pioneer investigators in this field were selected to be reviewed.

RESULTSSphK1/S1P pathway can be activated by hyperglycemia, advanced glycation end products, and many pro-inflammatory cytokines, which leads to fibronectin, transforming growth factor-β1 up-regulation and AP-1 activation. And then it could promote glomerular mesangial cells proliferation and extracellular matrix accumulation, mediating the initiation and progression of diabetic renal fibrosis.

CONCLUSIONSSphK1/S1P pathway is closely correlated with the pathogenesis of DN. The results suggest that SphK1/S1P pathway as a new target for clinically improving DN in future is of great prospect.

Diabetic Nephropathies ; enzymology ; metabolism ; Extracellular Matrix ; metabolism ; Humans ; Lysophospholipids ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Signal Transduction ; Sphingosine ; analogs & derivatives ; metabolism

Sphingosine 1-phosphate (S1P) is an important biologically active lysophospholipid that transmits signals through a family of G-protein-coupled receptors (GPCRs) to regulate the vital functions of several types of immune cells. The S1P GPCRs suppress both generation of specialized functional cytokines, such as IFN-gamma and IL-4, and proliferation of T-cells. Although S1P is chemotactic to T cells, B cells, dendritic cells, and natural killer cells, the major effect of S1P on the immune system is the regulation of lymphocyte recirculation and tissue distribution by S1P and S1P1. Chemotactic response of CD4+CD25+ regulatory T cells to S1P is reduced, but its optimal suppressive activities require S1P. FTY720, a new class of immunomodulator, is rapidly phosphorylated by sphingosine kinase 2 in vivo to form the biologically active phosphorylated-FTY720 (FTY720-P), which closely resembles S1P. The FTY720-P is a true agonist for S1P1, S1P3, S1P4, and S1P5, it affects the tissue distribution and functional activity of T cells, B cells, dendritic cells and regulatory T cells. FTY720 were demonstrated to be a hypotoxic, great effective and reversible immunosuppressive efficacy to prevent allograft rejection and treat some autoimmune diseases. In this article, the synthesis and metabolism of S1P, the expression of S1P GPCRs in immune cells, the effect of S1P on immune cells, the drugs targeted to S1P GPCRs and their clinical implications are reviewed.
Fingolimod Hydrochloride ; Humans ; Immunomodulation ; physiology ; Lysophospholipids ; immunology ; physiology ; Propylene Glycols ; metabolism ; Receptors, G-Protein-Coupled ; immunology ; physiology ; Sphingosine ; analogs & derivatives ; immunology ; metabolism ; physiology

Sphingolipids, especially ceramide and S1P, are structural components of biological membranes and bioactive molecules which participate in diverse cellular activities such as cell division, differentiation, gene expression and apoptosis. Emerging evidence demonstrates the role of sphingolipids in hepatocellular death, which contributes to the progression of several liver diseases including ischaemia-reperfusion liver injury, steatohepatitis or hepatocarcinogenesis. Furthermore, some data indicate that the accumulation of some sphingolipids contributes to the hepatic dysfunctions. Hence, understanding of sphingolipid may open up a novel therapeutic avenue to liver diseases. This review focuses on the progress in the sphingolipid metabolic pathway with a focus on hepatic diseases and drugs targeting the sphingolipid pathway.
Apoptosis ; Ceramides ; metabolism ; Fatty Liver ; metabolism ; physiopathology ; Humans ; Liver Diseases ; metabolism ; physiopathology ; Lysophospholipids ; metabolism ; Reperfusion Injury ; metabolism ; physiopathology ; Sphingolipids ; metabolism ; Sphingosine ; analogs & derivatives ; metabolism