Sphingosine-1-phosphate (S1P) is the main metabolite produced in the process of phospholipid metabolism, which can promote proliferation, migration, and apoptosis of cells, and maintain the barrier function of vascular endothelium. The latest researches showed that S1P can alleviate acute lung injury (ALI) and the inflammation caused by ALI, while the dosage of S1P is still needed to be considered. Mesenchymal stem cells (MSCs) have been a emerging therapy with potential therapeutic effects on ALI because of their characteristics of self-replication and multi-directional differentiation, and their advantages in hematopoiesis, immune regulation, and tissue repair. S1P can promote differentiation of MSCs and participate in immune regulation, while MSCs can regulate the homeostasis of S1P in the body. The synergistic effect of S1P and MSC provides a new treatment method for ALI. This article reviews the production and biological function of S1P, receptor and signal pathway of S1P, the therapeutic effects of S1P on ALI, and the research advances of S1P combined with MSCs in the treatment of ALI, aiming to provide theoretical references for the development of S1P targeted drugs in the treatment of ALI and the search for new combined treatment schemes for ALI.
Acute Lung Injury ; Animals ; Lung/metabolism* ; Lysophospholipids/pharmacology* ; Mice ; Mice, Inbred C57BL ; Sphingosine/pharmacology*

The aim of the present study was to explore the role of orphan G protein-coupled receptor 55 (GPR55) in diabetic gastroparesis (DG). Streptozotocin (STZ) was used to mimic the DG model, and the body weight and blood glucose concentration were tested 4 weeks after STZ injection (i.p.). Electrogastrogram and phenolsulfonphthalein test were used for detecting gastric emptying. Motilin (MTL), gastrin (GAS), vasoactive intestinal peptide (VIP), and somatostatin (SS) levels in plasma were determined using radioimmunology. Real-time PCR and Western blot were applied to identify the expression of GPR55 in gastric tissue, and immunohistochemistry was used to detect the distribution. The effect of lysophosphatidylinositol (LPI), an agonist of GPR55, was observed. STZ mice showed increased blood glucose concentration, lower body weight, decreased amplitude of slow wave, and delayed gastric emptying. LPI antagonized these effects of STZ. Compared to the control group, STZ caused significant decreases of MTL and GAS levels (P < 0.01), as well as increases of SS and VIP levels (P < 0.01). The changes of these hormones induced by STZ were counteracted when using LPI. GPR55 located in mice stomach, and it was up-regulated in DG. Although LPI showed no effects on the distribution and expression of GPR55 in normal mice, it could inhibit STZ-induced GPR55 up-regulation. These results suggest GPR55 is involved in the regulation of gastric movement of DG, and may serve as a new target of DG treatment. LPI, an agonist of GPR55, can protect against STZ-induced DG, and the mechanism may involve the change of GPR55 expression and modification of gastrointestinal movement regulating hormones.
Animals ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Gastroparesis ; metabolism ; pathology ; Lysophospholipids ; pharmacology ; Mice ; Receptors, Cannabinoid ; metabolism

BACKGROUNDDiarrhea is a common clinical feature of ulcerative colitis resulting from unbalanced intestinal fluid and salt absorption and secretion. The Cl(-)/HCO3(-) exchanger SLC26A3 is strongly expressed in the mid-distal colon and plays an essential role in colonic Cl(-) absorption and HCO3(-) secretion. Slc26a3 expression is up-regulated by lysophosphatidic acid (LPA) in vitro. Our study was designed to investigate the effects of LPA on SLC26A3 expression and the diarrheal phenotype in a mouse colitis model.

METHODSColitis was induced in C57BL/6 mice by adding 4% of dextran sodium sulfate (DSS) to the drinking water. The mice were assigned to LPA treatment DSS group, phosphate-buffered saline (PBS) treatment DSS group, DSS only group and untreated mice with a completely randomized design. Diarrhea severity was evaluated by measuring mice weight, disease activity index (DAI), stool water content and macroscopic evaluation of colonic damage. The effect of LPA treatment on Slc26a3 mRNA level and protein expression in the different groups of mice was investigated by quantitative PCR and Western blotting.

RESULTSAll mice treated with DSS lost weight, but the onset and severity of weight loss was attenuated in the LPA treatment DSS group. The increases in stool water content and the macroscopic inflammation score in LPA treatment DSS group were significantly lower compared to DSS control group or PBS treatment DSS group ((18.89±8.67)% vs. (28.97±6.95)% or (29.48±6.71)%, P = 0.049, P = 0.041, respectively and 2.67±0.81 vs. 4.5±0.83 or 4.5±0.54, P = 0.020, P = 0.006, respectively), as well as the increase in DAI (P = 0.004, P = 0.008, respectively). LPA enema resulted in higher Slc26a3 mRNA and protein expression levels compared to PBS-treated and untreated DSS colitis mice.

CONCLUSIONLPA increases Slc26a3 expression in the inflamed intestine and reduces diarrhea severity in DSS-induced colitis, suggesting LPA might be a therapeutic strategy in the treatment of colitis associated diarrhea.

Animals ; Antiporters ; genetics ; metabolism ; Colitis ; chemically induced ; drug therapy ; Colon ; immunology ; metabolism ; Dextran Sulfate ; pharmacology ; Dextrans ; pharmacology ; Diarrhea ; drug therapy ; metabolism ; Female ; Immunoblotting ; Intestines ; drug effects ; metabolism ; Lysophospholipids ; therapeutic use ; Mice ; Mice, Inbred C57BL

Sphingolipids as an important regulator play a critical role in the cell biological functions. Among them, ceramide (Cer) and sphingosine (Sph) induce apoptosis and inhibit cell proliferation; on the contrary sphingosine 1-phosphate (S1P) promotes cell survival and proliferation. The balance between ceramide/sphingosine and S1P forms a so-called "sphingolipid-rheostat", which decides the cell fate. Sphingosine kinases, which catalyze the phosphorylation of sphingosine to S1P, are critical regulators of this balance. Here, we review the role of sphingosine kinase 1 (SphK1) in regulating fundamental biological processes and tumorigenesis and the potential of SphK1 as a new target for cancer therapeutics.
Amino Alcohols ; pharmacology ; Animals ; Apoptosis ; drug effects ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Ceramides ; metabolism ; Enzyme Activation ; Enzyme Inhibitors ; pharmacology ; Humans ; Lysophospholipids ; metabolism ; Neoplasms ; metabolism ; pathology ; Neovascularization, Pathologic ; Phosphorylation ; Phosphotransferases (Alcohol Group Acceptor) ; antagonists & inhibitors ; metabolism ; Sphingosine ; analogs & derivatives ; metabolism ; Thiazoles ; pharmacology

To study the effect of sphingosine-1-phosphate (S1P) on the cardiomyogenic differentiation of human umbilical cord mesenchymal stem cells (UC-MSCs) and human adipose-derived mesenchymal stem cells (AD-MSCs), we seeded the cells in the culture plates and used cardiomyocyte culture medium (CMCM) combining with different concentration of S1P to induce UC-MSCs and AD-MSCs in vitro for 7, 14 and 28 days. Cardiomyogenic differentiations were identified through immunofluorescence staining, and the results were observed with fluorescence microscopy and confocal microscopy. The effects of S1P and CMCM on cell activity were evaluated by the methyl thiazolyl tetrazolium assay. The functional characteristic similar to cardiomyocytes was evaluated through detecting calcium transient. Our results showed that cardiomyogenic differentiation of UC-MSCs or AD-MSCs were enhanced with S1P concentration increasing, but cell activities declined. Results showed that the suitable differentiation time was 14 days, and the optimal concentration of S1P was 0.5 micromol/L. When working together with CMCM, S1P could promote the differentiation of UC-MSCs or AD-MSCs into functional cardiomyocytes, giving rise to specific electrophysiological properties (the calcium transient). Taken together, our results suggested that S1P could promote the differentiation of UC-MSCs or AD-MSCs into functional cardiomyocytes when being cultured in CMCM.
Adipose Tissue ; cytology ; metabolism ; Cell Differentiation ; drug effects ; Cells, Cultured ; Culture Media ; Humans ; Lysophospholipids ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Myocytes, Cardiac ; cytology ; Sphingosine ; analogs & derivatives ; pharmacology ; Umbilical Cord ; cytology

Phosphatidylinositol 3-kinase (PI3K) is essential for both G protein-coupled receptor (GPCR)- and receptor tyrosine kinase (RTK)-mediated cancer cell migration. Here, we have shown that maximum migration is achieved by full activation of phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) in the presence of Gbetagamma and PI3K signaling pathways. Lysophosphatidic acid (LPA)-induced migration was higher than that of epidermal growth factor (EGF)-induced migration; however, LPA-induced activation of Akt was lower than that stimulated by EGF. LPA-induced migration was partially blocked by either Gbetagamma or RTK inhibitor and completely blocked by both inhibitors. LPA-induced migration was synergistically increased in the presence of EGF and vice versa. In correlation with these results, sphingosine-1-phosphate (S1P)-induced migration was also synergistically induced in the presence of insulin-like growth factor-1 (IGF-1). Finally, silencing of P-Rex1 abolished the synergism in migration as well as in Rac activation. Moreover, synergistic activation of MMP-2 and cancer cell invasion was attenuated by silencing of P-Rex1. Given these results, we suggest that P-Rex1 requires both Gbetagamma and PI3K signaling pathways for synergistic activation of Rac, thereby inducing maximum cancer cell migration and invasion.
Cell Line, Tumor ; *Cell Movement/drug effects ; Enzyme Activation/drug effects ; GTP-Binding Protein beta Subunits/*metabolism ; GTP-Binding Protein gamma Subunits/*metabolism ; Guanine Nucleotide Exchange Factors/metabolism ; Humans ; Lysophospholipids/pharmacology ; Neoplasms/enzymology/*metabolism ; Phosphatidylinositol 3-Kinases/*metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Receptors, G-Protein-Coupled/metabolism ; Signal Transduction

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

OBJECTIVETo explore the mechanism of protective effect of Sphingosine-1-phosphate(S1P) in cultured neonatal rat cardiomyocytes dining simulated hypoxia/reoxygenation.

METHODSOn the basis of culturing neonatal rat cardiomyocytes, the model of hypoxia-reoxygennation was built by using method of Liquid Paraffin covering, the impact of S1P on apoptosis and p-Akt and mitochondrial membrane potential were studied by using method of Propidine Iodide staining and Western blot and Bhodanmine123 staining.

RESULTSSiP could reduce apoptosis rate (P < 0.01) and stabilize the mitochondrial membrane potential (P < 0.05) and improved the level of p-Akt1 (P < 0.01) in hypoxia/reoxygenation cardiomyocytes significantly. But wonnannin could block these effects of S1P partially.

CONCLUSIONSiP can obviously restrain apoptosis in curtured rat neonatal cardiomyocytes during simulated hypoxia/reoxygenation. Stabilization of mitochondrial membrane potential by P13K-AM signaling pathway is likely to play a role in protective action of S1P.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Cell Hypoxia ; Cells, Cultured ; Female ; Lysophospholipids ; pharmacology ; Male ; Membrane Potential, Mitochondrial ; drug effects ; Myocardial Reperfusion Injury ; prevention & control ; Myocytes, Cardiac ; cytology ; Oncogene Protein v-akt ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Primary Cell Culture ; Protective Agents ; pharmacology ; Rats ; Signal Transduction ; Sphingosine ; analogs & derivatives ; pharmacology

OBJECTIVETo investigate the effect and potential mechanism of lysophosphatidic acid (LPA) and antiarrhythmic peptide (AAP10) on rabbit ventricular arrhythmia.

METHODSTwenty-four rabbits were randomly divided into three groups (n = 8 each): control group, LPA group and AAP10 + LPA group. Using arterially perfused rabbit ventricular wedge preparations, transmural ECG and action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments with two separate floating microeletrodes. The incidence of ventricular arrhythmia post S1S2 stimulation was recorded. Protein levels of nonphosphorylated Cx43 and total Cx43 were evaluated by Western blot. The distribution of nonphosphorylated Cx43 was observed by confocal immunofluorescence microscopy.

RESULTSCompared with the control group, the QT interval, endocardial action potential duration, transmural repolarization dispersion (TDR) and incidence of ventricular arrhythmia were significantly increased and nonphosphorylated Cx43 expression was significantly upregulated in the LPA group. Compared with the LPA group, cotreatment with AAP10 can reduce the QT interval, endocardial action potential duration, TDR and incidence of ventricular arrhythmia (25.0% vs 62.5%, P < 0.01) and downregulate nonphosphorylated Cx43.

CONCLUSIONSLPA could promote the arrhythmia possibly by upregulating nonphosphorylated Cx43 and subsequent gap junction transmission inhibition. Gap junction enhancer AAP10 could attenuate the pro-arrhythmic effect of LPA probably by downregulating myocardial nonphosphorylated Cx43 expression.

Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; chemically induced ; metabolism ; physiopathology ; Connexin 43 ; metabolism ; Lysophospholipids ; adverse effects ; Oligopeptides ; pharmacology ; Rabbits

This study examined whether propofol and aminophylline affect the mobilization of intracellular calcium in human umbilical vein endothelial cells. Intracellular calcium was measured using laser scanning confocal microscopy. Cultured and serum-starved cells on round coverslips were incubated with propofol or aminophylline for 30 min, and then stimulated with lysophosphatidic acid, propofol and aminophylline. The results were expressed as relative fluorescence intensity and fold stimulation. Propofol decreased the concentration of intracellular calcium, whereas aminophylline caused increased mobilization of intracellular calcium in a concentration-dependent manner. Propofol suppressed the lysophosphatidic acid-induced mobilization of intracellular calcium in a concentration-dependent manner. Propofol further prevented the aminophylline-induced increase of intracellular calcium at clinically relevant concentrations. However, aminophylline reversed the inhibitory effect of propofol on the elevation of intracellular calcium by lysophosphatidic acid. Our results suggest that propofol and aminophylline antagonize each other on the mobilization of intracellular calcium in human umbilical vein endothelial cells at clinically relevant concentrations. Serious consideration should be given to how this interaction affects mobilization of intracellular calcium when these two drugs are used together.
Aminophylline/*antagonists & inhibitors/pharmacology ; Anesthetics, Intravenous/*antagonists & inhibitors/pharmacology ; Bronchodilator Agents/*antagonists & inhibitors/pharmacology ; Calcium/*metabolism ; Cells, Cultured ; Endothelial Cells/*drug effects/metabolism ; Endothelium, Vascular/cytology ; Humans ; Lysophospholipids/pharmacology ; Microscopy, Confocal ; Propofol/*antagonists & inhibitors/pharmacology ; Umbilical Veins/cytology