OBJECTIVES: To investigate the role of sphingosine-1-phosphate receptor 5 (S1PR5) in modulating barrier function of mouse brain microvascular endothelial cells with oxygen-glucose deprivation and reoxygenation (OGD/R). METHODS: Mouse brain microvascular endothelial cells (bEnd.3) were exposed to OGD/R to induce barrier dysfunction following treatment with S1PR5-specific agonist A971432 or lentivirus-mediated transfection with a S1PR5-specific siRNA, a S1PR5-overexpressing plasmid, or their respective negative control sequences. The changes in viability and endothelial barrier permeability of the treated cells were evaluated with CCK-8 assay and FITC-dextran permeability assay; the levels of intracellular reactive oxygen species (ROS) and localization and expression levels of the proteins related with barrier function and oxidative stress were detected using immunofluorescence staining, DCFH-DA probe and Western blotting. RESULTS: S1PR5 activation obviously enhanced viability of bEnd.3 cells exposed to OGD/R (P<0.0001). Both activation and overexpression of S1PR5 reduced FITC-dextran leakage, while S1PR5 knockdown significantly increased FITC-dextran leakage in the exposed bEnd.3 cells. Activation and overexpression of S1PR5 both increased the cellular expressions of the barrier proteins ZO-1 and occludin, while S1PR5 knockdown produced the opposite effect. In cells exposed to OGD/R, ROS production was significantly reduced by S1PR5 activation and overexpression but increased following S1PR5 knockdown. Overexpression of S1PR5 obviously increased the expressions of the antioxidant proteins Nrf2, HO-1 and SOD2 in the exposed cells. CONCLUSIONS S1PR5 activation and overexpression significantly improve cell viability and reduce permeability of a mouse brain microvascular endothelial cell model of OGD/R, the mechanism of which may involve the reduction in ROS production and upregulation of the antioxidant proteins.
Animals ; Mice ; Oxidative Stress ; Endothelial Cells/cytology* ; Brain/blood supply* ; Reactive Oxygen Species/metabolism* ; Receptors, Lysosphingolipid/metabolism* ; Sphingosine-1-Phosphate Receptors ; Blood-Brain Barrier/metabolism* ; Glucose ; Cell Line ; Oxygen/metabolism* ; NF-E2-Related Factor 2/metabolism*

OBJECTIVE: To observe the expressions of sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate receptor 2 (S1PR2) in hippocampus of epileptic rats and to investigate the pathogenesis of SphK1 and S1PR2 in epilepsy. METHODS: One hundred and eight male Sprague-Dawley (SD) rats were randomly divided into control group (n=48) and pilocarpine (PILO) group (n=60). A robust convulsive status epilepticus (SE) was induced in PILO group rats by the application of pilocarpine. Control group rats were injected with respective of physiological saline. Pilocarpine group was randomly divided into 6 subgroups (n=8): acute group (E6 h, E1 d, E3 d), latent group (E7 d) and chronic group (E30 d, E56 d). Each subgroup has 8 control rats and 8 epileptic rats. Hippocampal tissue and brain slices were obtained from control rats and rats subjected to the Li-PILO model of epilepsy at 6 h, 1 d, 3 d,7 d,30 d and 56 d after status epilepticus (SE). Western blot technique was used to determine the expressions of SphK1 and S1PR2 in hippocampus at different point of time after pilocarpine treatment. Immunofluorescence was applied to detect the activation and proliferation of hippocampal astrocytes and the localization of SphK1 and S1PR2 in rat hippocampal astrocytes. RESULTS: Compared with control group, the levels of SphK1 in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d) were significantly increased while the expressions of S1PR2 were decreased in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d)(P＜0.05 or P＜0.01). Immunofluorescence results showed astrocyte activation and proliferation in hippocampus of epileptic (E7 d) rats (P＜0.05). Confocal microscopy confirmed the preferential expressions of SphK1 and S1PR2 in epileptic rat(E7 d)hippocampal astrocytes. CONCLUSION The results indicate that SphK1 and S1PR2 may play an important role in the pathogenesis of epilepsy by regulating the activation and proliferation of hippocampal astrocytes and altering neuronal excitability.
Animals ; Astrocytes ; enzymology ; Epilepsy ; enzymology ; physiopathology ; Hippocampus ; cytology ; enzymology ; Male ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Pilocarpine ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Lysosphingolipid ; metabolism

Objective: To screen lentiviral vectors carrying siRNA which can specifically down-regulate the gene expression of the sphingosine-1-phosphate receptor 3 (S1PR3) in the corpus cavernosum smooth muscle (CCSM) cells of rats with spontaneous hypertension (SHT) and investigate the influence of the vectors on the signaling pathways of ROCK1, ROCK2 and eNOS in the CCSM cells of SHT rats. METHODS: Using the S1PR3 mRNA sequence of the rat as an interfering target, we designed and synthesized three pairs of siRNA sequences (siRNA1, 2 and 3) targeting S1PR3 and one pair of negative control, and then constructed and packaged them into lentiviral vectors. We cultured the CCSM cells of SHT and Wistar-Kyoto (WKY) rats in vitro and randomly divided them into groups A (SHT untransfected control), B (SHT transfected and carrying negative control virus), C (SHT transfected and carrying siRNA1 targeting S1PR3), D (SHT transfected and carrying siRNA2 targeting S1PR3), E (SHT transfected and carrying siRNA3 targeting S1PR3), and F (WKY untransfected control). With the multiplicity of infection (MOI) = 60, we transfected the CCSM cells of the SHT rats with the lentiviral vector and then determined the expression of the green fluorescent protein (GFP) as well as the mRNA and protein expressions of S1PR3, ROCK1, ROCK2 and eNOS in the CCSM cells of the SHT and WKY rats by RT-PCR and Western blot. RESULTS: Gene sequencing proved the successful construction of the lentiviral vector. The transfection efficiency of the CCSM cells of the rats was >80% in groups B, C, D and E. Compared with group A, the mRNA and protein expressions of S1PR3, ROCK1 and ROCK2 exhibited no significant difference in group B but were remarkably decreased in groups C, D, E and F (P< 0.05), most significantly in group E, with the inhibition rates of the mRNA and protein expressions of S1PR3 of (34.2±2.9) and (77.7±4.7)%, those of ROCK1 of (33.3±1.4) and (51.1±7.3)%, and those of ROCK2 of (30.8±3.6) and (58.32±5.5)%, respectively. The mRNA and protein expressions of eNOS in group A showed no significant difference from those in groups B, C, D and E (P>0.05) but remarkably lower than those in group F (P< 0.05). Compared with group F, the mRNA and protein expressions of S1PR3, ROCK1 and ROCK2 were not significantly different from those in group E (P>0.05) but markedly increased in groups A, B, C and D (P< 0.05), while those of eNOS remarkably decreased in groups A, B, C, D and E (P< 0.05). CONCLUSIONS The three constructed lentiviral vectors carrying siRNA targeting different loci of the S1PR3 gene could significantly inhibit the expression of S1P3 as well as RhoA/Rho kinase signaling pathways in the CCSM cells of SHT rats, and the vector carrying siRNA3 exhibited the highest inhibitory effect.
Animals ; Down-Regulation ; Gene Expression ; Genetic Vectors ; Green Fluorescent Proteins ; metabolism ; Lentivirus ; genetics ; Male ; Myocytes, Smooth Muscle ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Penis ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Inbred WKY ; Receptors, Lysosphingolipid ; genetics ; metabolism ; Signal Transduction ; Sphingosine-1-Phosphate Receptors ; Transfection ; rho-Associated Kinases ; metabolism

OBJECTIVETo investigate the expressions of sphingosine-1-phosphate receptors 1-3 (S1P1- 3) in the corpus cavernosum of castrated male rats and its relationship with the NOS/NO/cGMP and RhoA/Rho kinase signaling pathways.

METHODSWe equally randomized 18 eight-week-old healthy male SD rats into a sham-operation control, a castration, and a testosterone replacement (TR) group and harvested the bilateral testes and epididymides from the rats in the latter two groups, followed by 4 weeks of subcutaneous injection of testosterone propionate at 3 mg per kilogram of the body weight per day for those in the TR group and that of plant oil for those in the control and castration groups. At the age of 12 weeks, we measured the serum testosterone (T) level and maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP) of the animals and determined the expressions of SlP1-3, eNOS, P-eNOS, ROCK1, and ROCK2 in the corpus cavernosum by Western blot and immunohistochemistry.

RESULTSThe serum T level was significantly decreased in the rats of the castration group as compared with those of the control and TR groups ([0.41 ± 0.04] vs [16.01 ± 1.02] and [15.84 ± 1.32] nmol/L, P < 0.01), with no statistically significant difference between the latter two groups. The ICPmax/MAP at 0 V, 3 V, and 5 V electric stimulation was remarkably lower in the rats of the castration group (0.088 ± 0.014, 0.323 ± 0.014, and 0.432 ± 0.012) than in those of the control group (0.155 ± 0.011, 0.711 ± 0. 010, and 0.819 ± 0.024) and TR group (0.153 ± 0.012, 0.696 ± 0.017, and 0.763 ± 0.027) (P < 0.01), with no significant difference between the latter two groups. With GAPDH as internal control, the animals of the castration group showed markedly reduced expressions of S1P1 ([49.99 ± 3.39]%), eNOS ([46.82 ± 3.81]%) , and P-eNOS ([45.42 ± 4.35]%) in comparison with those in the control group ([72.57 ± 3.06], [89.76 ± 3.98], and [82.53 ± 8.92] and TR group ([71.77 ± 4.43], [87.19 ± 4.23], and [79.82 ± 7.38]%) (P < 0.01) , while the expressions of S1P2, S1P3, ROCK1, and ROCK2 were significantly upregulated in the castration group ([82.35 ± 4.13], [61.03 ± 5.14], [74.50 ± 4.02], and [69.83 ± 5.75]%) as compared with those in the control group ([41.67 ± 1.68], [31.66 ± 2.67], [35.69 ± 5.56], and [39.85 ± 7.17]%) and TR group ([42.80 ± 3.87], [32.25 ± 4.22], 38.06 ± 5.21], and [42.36 ± 4.44]%) (P < 0.01).

CONCLUSIONAndrogen deficiency induces significant reduction of ICPmax/ MAP in male rats, which is possibly associated with the decline of S1P1 in the corpus cavernosum, inhibition of the eNOS/NO/cGMP signaling pathway, increased expressions of S1P2 and S1P3, and activation of the RhoA/Rho kinase signaling pathway.

Animals ; Male ; Nitric Oxide Synthase Type III ; metabolism ; Orchiectomy ; Penis ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Lysosphingolipid ; metabolism ; Testosterone ; blood ; pharmacology ; rho-Associated Kinases ; metabolism

The aim of this study was to examine the priming effect of sphingosine 1-phosphate (S1P) on fMLP-activated neutrophils, mainly to detect the neutrophil respiratory burst products, and to investigate the signaling pathway involved in S1P activity. Flow cytometry was used to evaluate the new isolated neutrophil; the superoxide anion output was detected indirectly by cytochrome C reduction in respiratory burst; the dihydro-rhodamine 123 was used to detect the intensity of respiratory burst; the signal transduction pathways of neutrophil respiratory burst were explored by Western blot. The results showed that after pretreated with S1P, the level of superoxide anion released by fMLP-activated neutrophils significantly increased; the Rhodamine 123 mean fluorescence intensity in S1P primed fMLP-activated neutrophils group was significantly higher than that in fMLP treatment group; PI3K and Akt proteins involved in the signal pathway of neutrophil respiratory burst. It is concluded that S1P is a new priming reagent, which primes respiratory burst of fMLP-activated neutrophils; this signal pathway may be that S1P interacts with its receptor, activates PI3K, then activates Akt-transmitting signals through NADPH oxidase, finally results in the respiratory burst.
Cells, Cultured ; Humans ; Lysophospholipids ; metabolism ; NADPH Oxidases ; metabolism ; Neutrophils ; metabolism ; physiology ; Proto-Oncogene Proteins c-akt ; metabolism ; Receptors, Lysosphingolipid ; metabolism ; Respiratory Burst ; Signal Transduction ; Sphingosine ; analogs & derivatives ; metabolism ; Superoxides ; metabolism

Sphingosine-1-phosphate (S1P) is a lysophospholipid signaling molecule that regulates important biological functions in both intracellular and extracellular compartments. It interacts with five G protein-coupled receptors subtypes (S1PR(1-5)) to generate multiple downstream signaling. Activation of S1PR1 has been validated to be involved in the process of immune modulation. Fingolimod (FTY720), the novel S1PR1 agonist, has been approved for the treatment of multiple sclerosis in clinical trials. The study towards discovery of selective S1PR1 agonists has become hot spot for immunological diseases. This article summarized the research progress of S1PR1 agonists, emphasizing their structure types, structure-activity relationship and direction of development.
Animals ; Fingolimod Hydrochloride ; Humans ; Immunosuppressive Agents ; pharmacology ; therapeutic use ; Lysophospholipids ; physiology ; Multiple Sclerosis ; drug therapy ; Propylene Glycols ; pharmacology ; therapeutic use ; Receptors, Lysosphingolipid ; agonists ; classification ; metabolism ; physiology ; Sphingosine ; analogs & derivatives ; pharmacology ; physiology ; therapeutic use ; Structure-Activity Relationship

Natural killer (NK) cells can suppress the development of graft vs host disease (GVHD) while retaining antitumor response in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Sphingosine-1-phosphate receptor 5 (S1PR5) can regulate NK cell migration and distribution in vivo by interacting with sphingosine-1-phosphate (S1P). This study was aimed to investigate S1PR5 expression change of NK cells in allo-HSCT and to explore the relationship between S1PR5 change and frequency of acute/chronic graft-versus-host disease (aGVHD/cGVHD). The S1PR5 expression was detected by real time quantitative PCR in the RNA extracted from blood NK cells of 17 couples of donor and recipient one month after allo-HSCT. The results showed that S1PR5 mRNA level variations in NK cells of donors and recipients post-allo-HSCT were not statistically significant (0.235 ± 0.191 vs 0.330 ± 0.261, P > 0.05). S1PR5 expression of NK cells was significantly lower in patients with aGVHD than those in patient without aGVHD (0.973 ± 0.834 vs 6.166 ± 5.32, P < 0.05). Compared with the corresponding donor, S1PR5 expression levels of patient declined by more than 10 that caused the high incidence of aGVHD. No significant correlation was found between S1PR5 expression of NK cells and cGVHD (3.401 ± 2.324 vs 2.762 ± 1.972, P > 0.05). It is concluded that the decreased expression level of NK cells S1PR5 is associated with aGVHD occurrence. Possible mechanism is due to S1PR5 low expression affecting distribution of NK cells in vivo, so affecting the regulation of NK cells for aGVHD.
Graft vs Host Disease ; blood ; epidemiology ; metabolism ; Hematopoietic Stem Cell Transplantation ; adverse effects ; methods ; Humans ; Killer Cells, Natural ; metabolism ; Receptors, Lysosphingolipid ; metabolism ; Transplantation, Homologous ; adverse effects

FTY720 is a synthetic compound derived from the metabolites of Isaria sinclairii. Its unique chemical structure and mechanism appear to be distinctive from other known immunosuppressors. In the present study, the effect of FTY720 on immunosuppression and toxicity to heart was evaluated by detection of lymphocytes count, heart rate in rats, the survival time of the allografts of skin slice in mice and binding to S1P1 and S1P3 receptors by confocal. The results showed that FTY720 could induce lymphopenia, reduce the heart rates in rats and prolong the survival time of the allografts of skin slice in mice. The assay results on confocal showed that FTY720 can bind with S1P1 and S1P3 on surface of CHO-S1P1 and CHO-S1P3 cells. FTY720 could be developed for wide application for organ transplantation and self-immunity diseases.
Animals ; Cricetinae ; Cricetulus ; Female ; Fingolimod Hydrochloride ; Graft Survival ; drug effects ; Heart Rate ; drug effects ; Immunosuppressive Agents ; pharmacology ; Lymphocyte Count ; Lymphocytes ; cytology ; drug effects ; Lymphopenia ; chemically induced ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Microscopy, Confocal ; Propylene Glycols ; pharmacology ; Protein Binding ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Lysosphingolipid ; agonists ; metabolism ; Skin Transplantation ; Sphingosine ; analogs & derivatives ; pharmacology ; Transplantation, Homologous

OBJECTIVE: To investigate the variation of senescent endothelial function by regulating the sphingosine-1-phosphate receptor type 2 (S1P2) expression in cultured human umbilical vein endothelial cells (HUVECs). METHODS: The S1P2 receptor expression was regulated by transfecting the cDNA or shRNA of S1P2 in cultured HUVECs. The expression levels of S1P2 receptor in HUVECs were detected by RT-PCR and Western blot. EC chemotaxis was measured by the transwell migration assay. The wound healing assay was performed by a scratch wound model on EC monolayer. Matrigel morphogenesis assay was employed to assess the in vitro angiogenic responses. RESULTS: After up-regulating the S1P2 expression in young ECs, the S1P-stimulated formation of a tubular-like network in Matrigel was dramatically diminished in transfected ECs (P<0.05). Quantification of the wound healing assay showed that transfected ECs grew much slower than young ECs (P<0.05). The chemotactic capability was significantly decreased in transfected ECs (P<0.05). Furthermore, the senescent-associated impairments were revoked by the downregulation of S1P2 receptor in senescent HUVECs. CONCLUSION The impaired functions (chemotactic, wound-healing and morphogenetic responses) in senescent HUVECs in vitro are mediated by S1P2 receptor.
Cells, Cultured ; Cellular Senescence ; genetics ; Human Umbilical Vein Endothelial Cells ; cytology ; physiology ; Humans ; RNA Interference ; RNA, Small Interfering ; genetics ; Receptors, Lysosphingolipid ; genetics ; metabolism ; Sphingosine-1-Phosphate Receptors ; Transfection ; Up-Regulation

CD4+ T cells mainly interact with Sphingosine 1-phosphate (S1P) to regulate immune function through Sphingosine 1-phosphate receptor 1 (S1P1). This study was aimed to investigate the effects of recombinant human granulocyte-colony-stimulating factor (rhG-CSF) mobilization on S1P1 expression in CD4+ T cells of donor's peripheral blood. The CD4+T cells of peripheral blood were isolated by magnetic beads from 17 allo-hematopoietic stem cell transplantation (allo-HSCT) donors before and at fourth day of mobilization with rhG-CSF. The S1P1 expression was detected by real time quantitative PCR in the RNA extracted from CD4+ T cells collected before and after rhG-CSF mobilization. The results showed that the expression of S1P1 was found in CD4+ cells before and after rhG-CSF mobilization, but the expression level of SIP1 in CD4+ cells after rhG-CSF mobilization was significantly lower than that before rhG-CSF mobilization (p<0.01). It is concluded that the mobilization with rhG-CSF obviously down-regulates the expression of S1P1 in CD4+ T cells of donor's peripheral blood.
CD4-Positive T-Lymphocytes ; drug effects ; metabolism ; Granulocyte Colony-Stimulating Factor ; pharmacology ; Hematopoietic Stem Cell Mobilization ; methods ; Hematopoietic Stem Cell Transplantation ; Humans ; Receptors, Lysosphingolipid ; metabolism ; Recombinant Proteins