Role Of Sphingosine-1-phosphate Signaling Research Articles

The Crosstalk between FcεRI and Sphingosine Signaling in Allergic Inflammation.

Sphingolipid molecules have recently attracted attention as signaling molecules in allergic inflammation diseases. Sphingosine-1-phosphate (S1P) is synthesized by two isoforms of sphingosine kinases (SPHK 1 and SPHK2) and is known to be involved in various cellular processes. S1P levels reportedly increase in allergic inflammatory diseases, such as asthma and anaphylaxis. FcεRI signaling is necessary for allergic inflammation as it can activate the SPHKs and increase the S1P level; once S1P is secreted, it can bind to the S1P receptors (S1PRs). The role of S1P signaling in various allergic diseases is discussed. Increased levels of S1P are positively associated with asthma and anaphylaxis. S1P can either induce or suppress allergic skin diseases in a context-dependent manner. The crosstalk between FcεRI and S1P/SPHK/S1PRs is discussed. The roles of the microRNAs that regulate the expression of the components of S1P signaling in allergic inflammatory diseases are also discussed. Various reports suggest the role of S1P in FcεRI-mediated mast cell (MC) activation. Thus, S1P/SPHK/S1PRs signaling can be the target for developing anti-allergy drugs.

New mechanism for mesenchymal stem cell microvesicle to restore lung permeability: intracellular S1P signaling pathway independent of S1P receptor-1

BackgroundMicrovesicles (MVs) derived from human bone marrow mesenchymal stem cell (MSC) were demonstrated to restore lung protein permeability and attenuate acute lung injury. In our previous study, we found that MSC MV increased sphingosine-1-phosphate (S1P) kinase1 mRNA levels in injured human lung microvascular endothelial cells (HLMVEC) significantly. However, the role of S1P signaling in MSC MV to restore lung protein permeability is unknown.MethodsIn this study, we hypothesized that MSC MV might restore lung permeability in part through increasing intracellular S1P signaling pathway in injured HLMVEC independent of S1P receptors. We used the transwell co-culture system to study the effect of MSC MV on protein permeability of Lipopolysaccharide (LPS) damaged HLMVEC.ResultsOur results showed that LPS significantly increased the permeability of HLMVEC to FITC-dextran (70 kDa) within 24 h. MSC MV restores this permeability and, to a large extent, prevents the cytoskeleton protein F-actin from recombining into “actin stress fibers,” and restores the positions of tight junctions and adhesion junctions in the damaged HLMVEC. This therapeutic effect of MSC MV was related to the increase in the S1P level in injured HLMVEC and was not eliminated when adding the antagonist of S1P receptor, suggesting that MSC MV to restore lung permeability was independent of S1P receptors on HLMVEC. Laser confocal further observed that Ca2+ mobilization and Rac1 activation in LPS injured HLMVEC were increased in parallel with the increase in intracellular S1P level after MSC MV treatment.ConclusionsIn short, MSC MV partially restored protein permeability across HLMVEC through the intracellular S1P signaling pathway independent of S1P receptor-1.

Skeletal Muscle and COVID-19: The Potential Involvement of Bioactive Sphingolipids

SARS-CoV-2 virus infection is the cause of the coronavirus disease 2019 (COVID-19), which is still spreading over the world. The manifestation of this disease can range from mild to severe and can be limited in time (weeks) or persist for months in about 30–50% of patients. COVID-19 is considered a multiple organ dysfunction syndrome and the musculoskeletal system manifestations are beginning to be considered of absolute importance in both COVID-19 patients and in patients recovering from the SARS-CoV-2 infection. Musculoskeletal manifestations of COVID-19 and other coronavirus infections include loss of muscle mass, muscle weakness, fatigue or myalgia, and muscle injury. The molecular mechanisms by which SARS-CoV-2 can cause damage to skeletal muscle (SkM) cells are not yet well understood. Sphingolipids (SLs) represent an important class of eukaryotic lipids with structural functions as well as bioactive molecules able to modulate crucial processes, including inflammation and viral infection. In the last two decades, several reports have highlighted the role of SLs in modulating SkM cell differentiation, regeneration, aging, response to insulin, and contraction. This review summarizes the consequences of SARS-CoV-2 infection on SkM and the potential involvement of SLs in the tissue responses to virus infection. In particular, we highlight the role of sphingosine 1-phosphate signaling in order to aid the prediction of novel targets for preventing and/or treating acute and long-term musculoskeletal manifestations of virus infection in COVID-19.

Mechanisms of sphingosine-1-phosphate (S1P) signaling on excessive stress-induced root resorption during orthodontic molar intrusion.

The aim of this study was to investigate cementocyte mechanotransduction during excessive orthodontic intrusive force-induced root resorption and the role of S1P signaling in this process. Fifty-four 12-week-old male Wistar rats were randomly divided into 3 groups: control group (Control), intrusive stress application group (Stress), and intrusive stress together with S1PR2-specific antagonist injection group (Stress + JTE). A rat molar intrusion model was established on animals in the Stress and the Stress + JTE groups. The animals in the Stress + JTE group received daily intraperitoneal (i.p.) injection of S1PR2 antagonist JTE-013, while the Control and Stress groups received only the vehicle. Histomorphometric, immunohistochemical, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses were performed after euthanizing of the rats. Root resorption was promoted in the Stress group with increased volumes of resorption pits and amounts of molar intrusion compared with the Control group. The expression levels of cementogenic- and cementoclastic-related factors were affected under excessive intrusive force. Immunohistochemical staining and qRT-PCR analysis showed promoted S1P signaling activities during molar intrusion. Western blot analysis indicated decreased nuclear translocation of β-catenin under excessive intrusive force. Through the administration of JTE-013, S1P signaling activity was suppressed and excessive intrusive force-induced root resorption was reversed. The regulation of S1P signaling could also influence the nuclear translocation of β-catenin and the expressions of cementogenic- and cementoclastic-related factors. Root resorption was promoted under excessive orthodontic intrusive force due to the disruption of cementum homeostasis. S1P signaling pathway might play an important role in cementocyte mechanotransduction in this process. The S1P signaling might be a promising therapeutic target for novel therapeutic approaches to prevent external root resorption caused by excessive orthodontic intrusive force.

S1P Signalling Differentially Affects Migration of Peritoneal B Cell Populations In Vitro and Influences the Production of Intestinal IgA In Vivo.

Introduction: Sphingosine-1-phosphate (S1P) regulates the migration of follicular B cells (B2 cells) and directs the positioning of Marginal zone B cells (MZ B cells) within the spleen. The function of S1P signalling in the third B cell lineage, B1 B cells, mainly present in the pleural and peritoneal cavity, has not yet been determined. Methods: S1P receptor expression was analysed in peritoneal B cells by real-time polymerase chain reaction (qPCR). The chemotactic response to S1P was studied in vitro. The role of S1P signalling was further explored in a s1p4−/− mouse strain. Results: Peritoneal B cells expressed considerable amounts of the S1P receptors 1 and 4 (S1P1 and S1P4, respectively). S1P1 showed differential expression between the distinct peritoneal B cell lineages. While B2 cells showed no chemotactic response to S1P, B1 B cells showed a migration response to S1P. s1p4−/− mice displayed significant alterations in the composition of peritoneal B cell populations, as well as a significant reduction of mucosal immunoglobulin A (IgA) in the gut. Discussion: S1P signalling influences peritoneal B1 B cell migration. S1P4 deficiency alters the composition of peritoneal B cell populations and reduces secretory IgA levels. These findings suggest that S1P signalling may be a target to modulate B cell function in inflammatory intestinal pathologies.

Sphingosine 1-phosphate signaling contributes to cardiac inflammation, dysfunction, and remodeling following myocardial infarction

Sphingosine 1-phosphate (S1P) mediates multiple pathophysiological effects in the cardiovascular system. However, the role of S1P signaling in pathological cardiac remodeling following myocardial infarction (MI) remains controversial. In this study, we found that cardiac S1P greatly increased post-MI, accompanied with a significant upregulation of cardiac sphingosine kinase-1 (SphK1) and S1P receptor 1 (S1PR1) expression. In MI-operated mice, inhibition of S1P production by using PF543 (the SphK1 inhibitor) ameliorated cardiac remodeling and dysfunction. Conversely, interruption of S1P degradation by inhibiting S1P lyase augmented cardiac S1P accumulation and exacerbated cardiac remodeling and dysfunction. In the cardiomyocyte, S1P directly activated proinflammatory responses via a S1PR1-dependent manner. Furthermore, activation of SphK1/S1P/S1PR1 signaling attributed to β1-adrenergic receptor stimulation-induced proinflammatory responses in the cardiomyocyte. Administration of FTY720, a functional S1PR1 antagonist, obviously blocked cardiac SphK1/S1P/S1PR1 signaling, ameliorated chronic cardiac inflammation, and then improved cardiac remodeling and dysfunction in vivo post-MI. In conclusion, our results demonstrate that cardiac SphK1/S1P/S1PR1 signaling plays an important role in the regulation of proinflammatory responses in the cardiomyocyte and targeting cardiac S1P signaling is a novel therapeutic strategy to improve post-MI cardiac remodeling and dysfunction.

Sphingosine-1-phosphate lyase is an endogenous suppressor of pulmonary fibrosis: role of S1P signalling and autophagy

IntroductionIdiopathic pulmonary fibrosis (IPF) is characterised by accumulation of fibroblasts and myofibroblasts and deposition of extracellular matrix proteins. Sphingosine-1-phosphate (S1P) signalling plays a critical role in pulmonary fibrosis.MethodsS1P lyase (S1PL)...

Abstract 407: FTY720 suppressed CT26 murine colon cancer peritoneal carcinomatosis progression by decreasing tumor associated macrophages and TNF-alpha

Abstract Introduction: The median survival of colon cancer peritoneal carcinomatosis (PC), the dissemination of cancer cells throughout the abdominal cavity, is only 5-9 months, which is a reflection of lack of effective treatment. The tumor microenvironment of solid cancers is characterized by a reactive stroma with an abundance of inflammatory mediators. Tumor associated macrophages (TAM), one of major players in the connection between inflammation and cancer, control a number of functions of the tumor microenvironment. including development and progression of PC, since they produce TNF-alpha that promotes adhesion of cancer cells to the peritoneum. In advanced cancer, TNF-alpha increases the metabolic rate and reduces body weight, known as cachexia. Sphingosine-1-phosphate (S1P), a bioactive lipid mediator that is produced by sphingosine kinase 1 (SphK1) plays important roles in cancer progression through S1P receptor-1 (S1PR1). The aim of this study was to elucidate the role of S1P signaling in TAMs and TNF-alpha production in murine colon cancer PC model using FTY720, a pro-drug that is converted in vivo to a functional antagonist of S1PR1 that disrupts S1P signaling. Methods: A murine colon cancer PC model was generated by IP injection of CT26-luc cells in immune intact BALB/c mice. FTY720 was given by gavage 1mg/kg oral daily. Mice were sacrificed 13 days after CT26-luc-cells injection. Expression of TNF-alpha, F4/80, CD86, and CD206 were determined by qPCR. TNF-alpha expression was determined by immunohistochemistry. Results: FTY720 completely suppressed the progression of CT26 PC, which is evaluated by the number and total weight of PC nodules, and it preserved body weight loss in the statement of cachexia. Also FTY720 significantly decreased F4/80 mRNA levels in the PC nodules. However there were no significant differences in the CD86/CD206 ratios in the tumors of the both FTY720 treated group and no treated group, which suggests that there are no changes in M1/M2 composition of the macrophage population. TNF-alpha mRNA in the tumors was also significantly decreased by FTY720 treated group and FTY720 significantly decreased expression of TNF-alpha. Conclusion: Our results suggest that FTY720 significantly decreased numbers of TAMs and production of TNF-alpha in PC tumors, which resulted in suppression of PC progression. Given its additional favorable effect against cachexia, FTY720 may provide better quality of life in advanced colon cancer PC patients. Citation Format: Tomoyoshi Aoyagi, Dorit Avini, Masayuki Nagahashi, Akimitsu Yamada, Krista P. Terracina, Wei-Ching Huang, Kazunori Aoki, Yasunori Matsumoto, Sarah Spiegel, Hisahiro Matsubara, Kazuaki Takabe. FTY720 suppressed CT26 murine colon cancer peritoneal carcinomatosis progression by decreasing tumor associated macrophages and TNF-alpha. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 407. doi:10.1158/1538-7445.AM2015-407

Sphingosine Kinase 1 Deficiency Confers Protection against Hyperoxia-Induced Bronchopulmonary Dysplasia in a Murine Model: Role of S1P Signaling and Nox Proteins

Bronchopulmonary dysplasia of the premature newborn is characterized by lung injury, resulting in alveolar simplification and reduced pulmonary function. Exposure of neonatal mice to hyperoxia enhanced sphingosine-1-phosphate (S1P) levels in lung tissues; however, the role of increased S1P in the pathobiological characteristics of bronchopulmonary dysplasia has not been investigated. We hypothesized that an altered S1P signaling axis, in part, is responsible for neonatal lung injury leading to bronchopulmonary dysplasia. To validate this hypothesis, newborn wild-type, sphingosine kinase1(-/-) (Sphk1(-/-)), sphingosine kinase 2(-/-) (Sphk2(-/-)), and S1P lyase(+/-) (Sgpl1(+/-)) mice were exposed to hyperoxia (75%) from postnatal day 1 to 7. Sphk1(-/-), but not Sphk2(-/-) or Sgpl1(+/-), mice offered protection against hyperoxia-induced lung injury, with improved alveolarization and alveolar integrity compared with wild type. Furthermore, SphK1 deficiency attenuated hyperoxia-induced accumulation of IL-6 in bronchoalveolar lavage fluids and NADPH oxidase (NOX) 2 and NOX4 protein expression in lung tissue. In vitro experiments using human lung microvascular endothelial cells showed that exogenous S1P stimulated intracellular reactive oxygen species (ROS) generation, whereas SphK1 siRNA, or inhibitor against SphK1, attenuated hyperoxia-induced S1P generation. Knockdown of NOX2 and NOX4, using specific siRNA, reduced both basal and S1P-induced ROS formation. These results suggest an important role for SphK1-mediated S1P signaling-regulated ROS in the development of hyperoxia-induced lung injury in a murine neonatal model of bronchopulmonary dysplasia.

Sphingosine-1-phosphate receptor-3 signaling up-regulates epidermal growth factor receptor and enhances epidermal growth factor receptor-mediated carcinogenic activities in cultured lung adenocarcinoma cells

Sphingosine-1-phosphate (S1P) regulates a wide array of biological functions. However, the role of S1P signaling in tumorigenesis remains to be elucidated. In this study, we show that S1P receptor subtype 3 (S1P₃) is markedly up-regulated in a subset of lung adenocarcinoma cells compared to normal lung epithelial cells. Specific knockdown of S1P₃ receptors inhibits proliferation and anchorage-independent growth of lung adenocarcinoma cells. Mechanistically, we demonstrate that S1P₃ signaling increases epidermal growth factor receptor (EGFR) expression via the Rho kinase (ROCK) pathway in lung adenocarcinoma cells. Nuclear run-off analysis indicates that S1P/S1P₃ signaling transcriptionally increases EGFR expression. Knockdown of S1P₃ receptors diminishes the S1P-stimulated EGFR expression in lung adenocarcinoma cells. Moreover, S1P treatment greatly enhances EGF-stimulated colony formation, proliferation and invasion of lung adenocarcinoma cells. Together, these results suggest that the enhanced S1P₃-EGFR signaling axis may contribute to the tumorigenesis or progression of lung adenocarcinomas.

Role of sphingosine 1-phosphate signaling for the pathogenesis of autoimmune diseases

Sphingosine 1-phosphate (S1P) acts as an extracellular mediator by binding to G protein- coupled receptors, regulating cell proliferation, angiogenesis and inflammation. FTY720 (FTY) is a high-affinity agonist for S1P receptors, inducing internalization of receptors, rendering the cells unresponsive to S1P. Here, we review the role of S1P signaling for the pathogenesis of autoimmune diseases and the therapeutic effects of FTY on autoimmune diseases.

Spingosine-1-phosphate stimulates proliferation and counteracts interleukin-1 induced nitric oxide formation in articular chondrocytes

Sphingosine-1-phosphate (S1P) is a messenger molecule, with important functions in inflammation and wound healing. The present study was performed to elucidate a possible role of S1P signaling in articular chondrocytes. Human and bovine primary chondrocytes were cultured in monolayer. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect S1P receptor mRNA. Proliferation of S1P stimulated chondrocytes was measured by 3H-thymidine uptake. Supernatants of cultured bovine chondrocytes stimulated with S1P alone or in combination with interleukin-1beta (IL-1beta) were tested for nitric oxide (NO) formation and expression of inducible nitric oxide synthase (iNOS). Matrixmetalloprotease-13 (MMP-13) and aggrecanase-1 (ADAMTS-4) were evaluated using real-time PCR. Glycosaminoglycan (GAG) loss from bovine cartilage explants was evaluated using the dimethylene blue method. S1P1, S1P2 and S1P3 but not S1P4 and S1P5 receptor mRNA were detected in human and bovine chondrocytes. S1P dose dependently induced proliferation in bovine and human chondrocytes. S1P significantly reduced NO formation and iNOS mRNA and protein expression, both in un-stimulated and IL-1beta stimulated bovine chondrocytes. Furthermore, S1P dose dependently inhibited IL-1beta induced expression of ADAMTS-4 and MMP-13 and diminished IL-1beta mediated GAG depletion from cartilage explants. These results suggest that S1P provides an anti-catabolic signal in articular chondrocytes.