ST-2191, an Anellated Bismorpholino Derivative of Oxy-Fingolimod, Shows Selective S1P1 Agonist and Functional Antagonist Potency In Vitro and In Vivo.

Sphingosine 1-phosphate (S1P) is an extensively studied signaling molecule that contributes to cell proliferation, survival, migration and other functions through binding to specific S1P receptors. The cycle of S1P1 internalization upon S1P binding and recycling to the cell surface when local S1P concentrations are low drives T cell trafficking. S1P1 modulators, such as fingolimod, disrupt this recycling by inducing persistent S1P1 internalization and receptor degradation, which results in blocked egress of T cells from the secondary lymphoid tissues. The approval of these compounds for the treatment of multiple sclerosis has placed the development of S1PR modulators in the focus of pharmacological research, mostly for autoimmune indications. Here, we report on a novel anellated bismorpholino derivative of oxy-fingolimod, named ST-2191, which exerts selective S1P1 agonist and functional antagonist potency. ST-2191 is also effective in reducing the lymphocyte number in mice, and this effect is not dependent on phosphorylation by sphingosine kinase 2 for activity. These data show that ST-2191 is a novel S1P1 modulator, but further experiments are needed to analyze the therapeutic impact of ST-2191 in animal models of autoimmune diseases.

Sphingosine-1-phosphate modulates PAR1-mediated human platelet activation in a concentration-dependent biphasic manner.

Sphingosine 1-phosphate (S1P) is a bioactive signalling sphingolipid that is increased in diseases such as obesity and diabetes. S1P can modulate platelet function, however the direction of effect and S1P receptors (S1PRs) involved are controversial. Here we describe the role of S1P in regulating human platelet function and identify the receptor subtypes responsible for S1P priming. Human platelets were treated with protease-activated receptor 1 (PAR-1)-activating peptide in the presence or absence of S1P, S1PR agonists or antagonists, and sphingosine kinases inhibitors. S1P alone did not induce platelet aggregation but at low concentrations S1P enhanced PAR1-mediated platelet responses, whereas PAR1 responses were inhibited by high concentrations of S1P. This biphasic effect was mimicked by pan-S1PR agonists. Specific agonists revealed that S1PR1 receptor activation has a positive priming effect, S1PR2 and S1PR3 have no effect on platelet function, whereas S1PR4 and S1PR5 receptor activation have an inhibitory effect on PAR-1 mediated platelet function. Although platelets express both sphingosine kinase 1/2, enzymes which phosphorylate sphingosine to produce S1P, only dual and SphK2 inhibition reduced platelet function. These results support a role for SphK2-mediated S1P generation in concentration-dependent positive and negative priming of platelet function, through S1PR1 and S1PR4/5 receptors, respectively.

Battling COVID-19 Pandemic: Sphingosine-1-Phosphate Analogs as an Adjunctive Therapy?

With the sudden outbreak of COVID-19 patient worldwide and associated mortality, it is critical to come up with an effective treatment against SARS-CoV-2. Studies suggest that mortality due to COVID 19 is mainly attributed to the hyper inflammatory response leading to cytokine storm and ARDS in infected patients. Sphingosine-1-phosphate receptor 1 (S1PR1) analogs, AAL-R and RP-002, have earlier provided in-vivo protection from the pathophysiological response during H1N1 influenza infection and improved mortality. Recently, it was shown that the treatment with sphingosine-1-phosphate receptor 1 analog, CYM5442, resulted in the significant dampening of the immune response upon H1N1 challenge in mice and improved survival of H1N1 infected mice in combination with an antiviral drug, oseltamivir. Hence, here we suggest to investigate the possible utility of using S1P analogs to treat COVID-19.

ASP1126, a Novel Sphingosine-1-Phosphate-Selective Agonist With a Favorable Safety Profile, Prolongs Allograft Survival in Rats and Nonhuman Primates in Combination With Tacrolimus With a Broad Safety Margin for Bradycardia.

Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that acts through the members of a family of 5 G protein-coupled receptors (S1P1 to S1P5). Among these, S1P1 is a major regulator of lymphocyte trafficking. Fingolimod, whose active metabolite, fingolimod phosphate, acts as a nonselective S1P-receptor agonist, exerts its immunomodulatory effect, at least in part, by regulating lymphocyte trafficking via downregulation of S1P1 expression on lymphocytes. Here, we describe the pharmacologic profile of a novel S1P1 agonist, ASP1126. ASP1126 preferentially activated S1P1 compared to S1P3 in rat and human guanosine-5'-(γ-thio)-triphosphate (GTPγS) assays. Oral single administration of ASP1126 decreased the number of peripheral lymphocytes and repeated dosing showed a cumulative effect on lymphopenia in both rats and monkeys. ASP1126 prolonged allograft survival in a rat heterotopic heart transplantation model in combination with a subtherapeutic dose of tacrolimus that was independent of drug-drug interactions. In addition, in nonhuman primate (NHP) renal transplantation, pretreatment with ASP1126 reduced not only the number of naive T cells and central memory T cells but also effector memory T cells in the peripheral blood, all of which could contribute to acute graft rejection and prolonged allograft survival in combination with tacrolimus. Further, we confirmed that ASP1126 has a broad ranging safety margin with respect to its effect on lung weight in rats and bradycardia in NHPs, which were the adverse events found in clinical studies of fingolimod. ASP1126 with improved safety profile has the potential to be an adjunct therapy in combination with tacrolimus in clinical transplantation.

Past, Present and Future of Therapeutic Interventions Targeting Leukocyte Trafficking in Inflammatory Bowel Disease.

Studies in the 1990s using animal models of intestinal inflammation delineated the crucial molecules involved in leukocyte attraction and retention to the inflamed gut and associated lymphoid tissues. The first drug targeting leukocyte trafficking tested in inflammatory bowel diseases was the anti-ICAM-1 antisense oligonucleotide alicaforsen, showing only modest efficacy. Subsequently, the anti-α4 monoclonal antibody natalizumab proved efficacious for induction and maintenance of remission in Crohn's disease, but was associated with progressive multifocal leukoencephalopathy due to its ability to interfere with both α4ß1 and α4ß7 function. Later developments in this area took advantage of the fairly selective expression of MAdCAM-1 in the digestive organs, showing that vedolizumab, a more specific monoclonal antibody selectively blocking MAdCAM-1 binding to integrin α4ß7, was efficacious for induction and maintenance of remission in ulcerative colitis and Crohn's disease, and it was not associated with neurological complications. Currently, other drugs targeting the ß7 subunit, immunoglobulin superfamily molecules expressed on the endothelium, as well as blockade of lymphocyte recirculation in lymph nodes through modulation of sphingosine 1-phosphate receptors are under development. The potential use and risks of combined anti-trafficking therapy will be examined in this review.

Selective Sphingosine 1-Phosphate Receptor 1 Agonist Is Protective Against Ischemia/Reperfusion in Mice.

BACKGROUND AND PURPOSE: Growing evidence supports that the immunomodulatory drug fingolimod is protective in stroke. Fingolimod binds to 4 of 5 sphingosine-1-phosphate (S1P) receptors and, among other actions, it induces lymphopenia. In this study, we investigated whether a selective S1P1 agonist is protective in experimental stroke. METHODS: Drug selectivity was studied in vitro in cells overexpressing the human S1P receptors. Mice (n=54) received different doses of LASW1238 (3 or 10 mg/kg), fingolimod (1 mg/kg), or the vehicle intraperitoneal, and lymphopenia was studied at different time points. After intraluminal middle cerebral artery occlusion for 45 minutes and immediately after reperfusion, mice (n=56) received the drug treatment. At 24 hours, a neurological test was performed and infarct volume was measured. Treatment and all the analyses were performed in a blind fashion. RESULTS: In vitro functional assays showed that LASW1238 is a selective agonist of the S1P1 receptor. At 10 mg/kg, this compound induced sustained lymphopenia in mice comparable with fingolimod, whereas at 3 mg/kg it induced short-lasting lymphopenia. After ischemia, both LASW1238 (10 mg/kg) and fingolimod reduced infarct volume, but only LASW1238 (10 mg/kg) showed statistically significant differences versus the vehicle. The neurological function and plasma cytokine levels were not different between groups. CONCLUSIONS: The selective S1P1 agonist LASW1238 reduces infarct volume after ischemia/reperfusion in mice, but only when lymphopenia is sustained for at least 24 hours. S1P1 and lymphocytes are potential targets for drug treatment in stroke. Defining the best drug dosing regimens to control the extent and duration of lymphopenia is critical to achieve the desired effects.

Identification and synthesis of potent and selective pyridyl-isoxazole based agonists of sphingosine-1-phosphate 1 (S1P1).

The synthesis and structure-activity relationship (SAR) of a series of pyridyl-isoxazole based agonists of S1P1 are discussed. Compound 5b provided potent in vitro activity with selectivity, had an acceptable pharmacokinetic profile, and demonstrated efficacy in a dose dependent manner when administered orally in a rodent model of arthritis.

Potent and Selective Agonists of Sphingosine 1-Phosphate 1 (S1P1): Discovery and SAR of a Novel Isoxazole Based Series.

Sphingosine 1-phosphate (S1P) is the endogenous ligand for the sphingosine 1-phosphate receptors (S1P1-5) and evokes a variety of cellular responses through their stimulation. The interaction of S1P with the S1P receptors plays a fundamental physiological role in a number of processes including vascular development and stabilization, lymphocyte migration, and proliferation. Agonism of S1P1, in particular, has been shown to play a significant role in lymphocyte trafficking from the thymus and secondary lymphoid organs, resulting in immunosuppression. This article will detail the discovery and SAR of a potent and selective series of isoxazole based full agonists of S1P1. Isoxazole 6d demonstrated impressive efficacy when administered orally in a rat model of arthritis and in a mouse experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis.

Emerging Strategies to Enhance Homing and Engraftment of Hematopoietic Stem Cells.

Successful clinical outcomes from transplantation of hematopoietic stem cells (HSCs) depend upon efficient HSC homing to bone marrow (BM), subsequent engraftment, and, finally, BM repopulation. Homing of intravenously administered HSCs from peripheral blood (PB) through the circulation to the BM stem cell niches, which is the first critical step that precedes their engraftment, is enforced by chemotactic factors released in the BM microenvironment that chemoattract HSCs. These chemotactic factors include α-chemokine stromal-derived factor 1 (SDF-1), the bioactive phosphosphingolipids sphingosine-1-phosphate (S1P) and ceramid-1-phosphate (C1P), and the extracellular nucleotides ATP and UTP. Stem cells may also respond to a Ca(2+) or H(+) gradient by employing calcium- or proton-sensing receptors, respectively. In this review, we will present emerging strategies based on ex vivo manipulation of graft HSCs that are aimed at enhancing the responsiveness of HSCs to BM-secreted chemoattractants and/or promoting HSC adhesion and seeding efficiency in the BM microenvironment.

Mechanism of sphingosine-1-phosphate induced cardioprotection against I/R injury in diabetic rat heart: Possible involvement of glycogen synthase kinase 3ß and mitochondrial permeability transition pore.

There is growing evidence that diabetes mellitus causes attenuation of the bioactive metabolite of membrane sphingolipids, sphingosine-1-phosphate, and this may be a key mechanism in the decreased cardioprotective effect of ischaemic preconditioning (IPC) in the diabetic heart. Thus, this study has been designed to investigate the role and pharmacological potential of sphingosine-1-phosphate in diabetic rat heart. Diabetes was produced in Wistar rats by administration of a low dose of streptozotocin (STZ) (35 mg/kg, i.p., once) and feeding a high fat diet (HFD) for 6 weeks. Isolated rat heart was subjected to 30 min ischaemia followed by 120 min of reperfusion (I/R). The heart was subjected to pre-ischaemic treatment (before ischaemia for 20 min) and pharmacological preconditioning with the S1P agonist FTY720 (0.6 µmol/L) with and without atractyloside (an mPTP opener; in the last episode of reperfusion before I/R). Myocardial infarction was assessed in terms of increase in lactate dehydrogenase (LDH), creatinine kinase-MB (CK-MB), myeloperoxidase (MPO) level and infarct size (triphenyltetrazolium chloride staining). Immunohistochemistry analysis was done for assessment of tumour necrosis factor (TNF)-α and glycogen synthase kinase (GSK)-3ß level in cardiac tissue. Pre-ischaemic treatment and pharmacological preconditioning with FTY720 significantly decreased I/R-induced myocardial infarction, TNF-alpha, GSK-3ß level and release of LDH and CK-MB as compared to control group. The cardioprotective effect of S1P agonist was significantly attenuated by atractyloside. It may be concluded that S1P agonist FTY720 prevents the diabetic heart from ischaemic reperfusion injury, possibly through inhibition of GSK-3ß and regulation of opening of mitochondrial permeability transition pore.

Recruitment of mesenchymal stem cells and macrophages by dual release of stromal cell-derived factor-1 and a macrophage recruitment agent enhances wound closure.

In this study, the wound closure of mouse skin defects was examined in terms of recruitment of mesenchymal stem cells (MSC) and macrophages. For the cells recruitment, stromal derived factor-1 (SDF-1) of a MSC recruitment agent and sphingosine-1 phosphate agonist (SEW2871) of a macrophages recruitment agent were incorporated into gelatin hydrogels, and then released in a controlled fashion. When applied to a skin wound defect of mice, gelatin hydrogels incorporating mixed 500 ng SDF-1 and 0.4, 0.8, or 1.6 mg SEW2871-micelles recruited a higher number of both MSC and macrophages than those incorporating SDF-1 or phosphate buffered saline. However, the number of M1 phenotype macrophages for the hydrogel incorporating mixed SDF-1 and SEW2871-micelles recruited was remarkably low to a significant extent compared with that for those hydrogel incorporating 0.4, 0.8, or 1.6 mg SEW2871-micelles. On the other hand, the number of M2 macrophages 3 days after the implantation of the hydrogels incorporating SDF-1 and 0.4 mg SEW2871-micelles significantly increased compared with that for other hydrogels. In vivo experiments revealed the hydrogels incorporating SDF-1 and 0.4 mg SEW2871-micelles promoted the wound closure of skin defect to a significant stronger extent than those incorporating SEW2871-micelles, SDF-1, and a mixture of SDF-1 and higher doses of SEW2871-micelles. It is concluded that the in vivo recruitment of MSC and macrophages to the defects may contribute to the tissue regeneration of skin wound.

HDL-bound sphingosine-1-phosphate restrains lymphopoiesis and neuroinflammation.

Lipid mediators influence immunity in myriad ways. For example, circulating sphingosine-1-phosphate (S1P) is a key regulator of lymphocyte egress. Although the majority of plasma S1P is bound to apolipoprotein M (ApoM) in the high-density lipoprotein (HDL) particle, the immunological functions of the ApoM-S1P complex are unknown. Here we show that ApoM-S1P is dispensable for lymphocyte trafficking yet restrains lymphopoiesis by activating the S1P1 receptor on bone marrow lymphocyte progenitors. Mice that lacked ApoM (Apom(-/-)) had increased proliferation of Lin(-) Sca-1(+) cKit(+) haematopoietic progenitor cells (LSKs) and common lymphoid progenitors (CLPs) in bone marrow. Pharmacological activation or genetic overexpression of S1P1 suppressed LSK and CLP cell proliferation in vivo. ApoM was stably associated with bone marrow CLPs, which showed active S1P1 signalling in vivo. Moreover, ApoM-bound S1P, but not albumin-bound S1P, inhibited lymphopoiesis in vitro. Upon immune stimulation, Apom(-/-) mice developed more severe experimental autoimmune encephalomyelitis, characterized by increased lymphocytes in the central nervous system and breakdown of the blood-brain barrier. Thus, the ApoM-S1P-S1P1 signalling axis restrains the lymphocyte compartment and, subsequently, adaptive immune responses. Unique biological functions imparted by specific S1P chaperones could be exploited for novel therapeutic opportunities.

Emerging biology of sphingosine-1-phosphate: its role in pathogenesis and therapy.

Membrane sphingolipids are metabolized to sphingosine-1-phosphate (S1P), a bioactive lipid mediator that regulates many processes in vertebrate development, physiology, and pathology. Once exported out of cells by cell-specific transporters, chaperone-bound S1P is spatially compartmentalized in the circulatory system. Extracellular S1P interacts with five GPCRs that are widely expressed and transduce intracellular signals to regulate cellular behavior, such as migration, adhesion, survival, and proliferation. While many organ systems are affected, S1P signaling is essential for vascular development, neurogenesis, and lymphocyte trafficking. Recently, a pharmacological S1P receptor antagonist has won approval to control autoimmune neuroinflammation in multiple sclerosis. The availability of pharmacological tools as well as mouse genetic models has revealed several physiological actions of S1P and begun to shed light on its pathological roles. The unique mode of signaling of this lysophospholipid mediator is providing novel opportunities for therapeutic intervention, with possibilities to target not only GPCRs but also transporters, metabolic enzymes, and chaperones.

Efectos cardioprotectores de reducción de tamaño del infarto de miocardio y prevención del remodelado ventricular postinfarto del adonista del receptor de esfingosina-1-fosfato: estudio experimental en un modelo porcino de isquemia-reperfusión / No disponible

La isquemia miocárdica induce fenómenos de muerte celular por necrosis y apoptosis. La apoptosis es un proceso que requiere energía (dependiente de oxígeno y ATP), por lo que -aunque los genes proapoptóticos se activen durante la isquemia- el programa apoptótico no se lleva a cabo hasta la reperfusión (cuando el oxígeno está nuevamente disponible para sintetizar ATP). La esfingosina 1-fosfato es un fosfolípido presente en el cuerpo con propiedades antiapoptóticas ya demostradas. Fingolimod es el único agonista sintético del receptor de esfingosina 1-fosfato (S1P-R) que está aprobado para uso en pacientes (en concreto, para esclerosis múltiple). Nuestra hipótesis consiste en que la activación del receptor S1P-R mediante el tratamiento con Fingolimod durante el periodo isquémico del infarto agudo de miocardio disminuye la apoptosis, aumenta el miocardio preservado, reduce el tamaño de infarto y mitiga el remodelado del ventrículo izquierdo en un modelo porcino de isquemia-reperfusión (I-R). Se indujo isquemia-reperfusión en cerdos Yorkshire mediante la oclusión percutánea de la arteria coronaria descendente anterior en su segmento proximal durante 60 minutos. Los animales fueron aleatorizados a recibir Fingolimod o salino (grupo control). Los animales fueron evaluados con resonancia magnética cardiaca (RM), ecocardiografía 3D, técnicas de hemodinámica invasiva, histología y análisis por Western blot. En un estudio inicial, se observó los cerdos tratados con Fingolimod presentaban a las 24 horas post-IAM menos apoptosis en el miocardio isquémico y más activación de proteínas cardioprotectoras y anti-apoptóticas que los cerdos del grupo control. En un estudio a largo plazo, la RM cardiaca una semana post-infarto (IAM) mostró que, a pesar de tener un tamaño similar de área en riesgo en el miocardio en ambos grupos, Fingolimod redujo significativamente el tamaño del infarto y mejoró la función sistólica del ventrículo izquierdo (VI). Estos efectos cardioprotectores seguían asimismo presentes un mes post-IAM, pues los cerdos tratados con Fingolimod presentaban menor tamaño de IAM, mejor función sistólica de VI y menor remodelado cardiaco a nivel anatómico (expresado como menos dilatación de VI, menor masa de VI y menor pérdida de la morfología normal del VI). Adicionalmente, Fingolimod mitigó el desarrollo del remodelado adverso del ventrículo izquierdo a nivel histológico (una disminución de la hipertrofia de los cardiomiocitos y de la fibrosis intersticial) y molecular (menor activación de Akt y de ERK1/2). Finalmente, el grupo Fingolimod presentaba asimismo menor activación neurohormonal (medida como menores niveles de catecolaminas). La activación precoz de S1P-R mediante el tratamiento con Fingolimod previo a la reperfusión provoca efectos cardioprotectores beneficiosos, incrementa el miocardio salvado, reduce el tamaño de infarto, mejora la función sistólica y la mecánica miocárdica del VI y mitiga el remodelado cardiaco adverso post-IAM

Myocardic ischemia induces cell death due to necrosis or apoptosis. Apoptosis requires energy (obtained from oxygen and ATP). Th Although proapoptotic genes are activated during ischemia the apoptotic programm does not take place until re-perfusion (when oxygen is again available to synthesize ATP). Sphingosine -1-phosphate is a phospholipid with known antiapoptotic properties. Fingolimod is the only synthetic agonist known of spingosine-1-phosphate receptor ( S1P-R) aproved for use in patients ( with multiple sclerosis). Our hypotheis is that activation of S-1-P R with Fingolimod during the period of ischemia of acute myocardic infartion decreases apoptosis, reduce the size and the process of remodeling of left ventricle in a porcine model of ischemia-reperfusion (I-R). Thus, I-R was induced in Yorkshire pigs by oclusión of coronary ateria in its proximal segment during 60 min. and treated or not with Fingolimod. Animals were evaluated by cardiac magnetic resonance (RM), ecocardiography 3D, hemodynamic tecniques, histology and Western blot analysis. Pigs treated with Fingolimod after 24 hr showed lower apoptosis of the myocardium and activation of antiapototic proteins Tan control group. In a long term study Fingolimod reduced the size of infartion and improved sustolic function of left ventricle. In addition Fingolimod decreased cardiomyocites hypertrophy and activation of molecular parameters as Akt and ERK 1/2. We conclude that early activation of S1P-R by Fingolimod reduces the size of infartion improves systolic function and mitigates adverse cardiac remodelling

S1P-Dependent trafficking of intracellular yersinia pestis through lymph nodes establishes Buboes and systemic infection.

Pathologically swollen lymph nodes (LNs), or buboes, characterize Yersinia pestis infection, yet how they form and function is unknown. We report that colonization of the draining LN (dLN) occurred due to trafficking of infected dendritic cells and monocytes in temporally distinct waves in response to redundant chemotactic signals, including through CCR7, CCR2, and sphingosine-1-phospate (S1P) receptors. Retention of multiple subsets of phagocytes within peripheral LNs using the S1P receptor agonist FTY720 or S1P1-specific agonist SEW2871 increased survival, reduced colonization of downstream LNs, and limited progression to transmission-associated septicemic or pneumonic disease states. Conditional deletion of S1P1 in mononuclear phagocytes abolished node-to-node trafficking of infected cells. Thus, Y. pestis-orchestrated LN remodeling promoted its dissemination via host cells through the lymphatic system but can be blocked by prevention of leukocyte egress from DLNs. These findings define a novel trafficking route of mononuclear phagocytes and identify S1P as a therapeutic target during infection.

Neutrophils exhibit differential requirements for homing molecules in their lymphatic and blood trafficking into draining lymph nodes.

Although much is described about the molecules involved in neutrophil migration from circulation into tissues, less is known about the molecular mechanisms that regulate neutrophil entry into lymph nodes (LNs) draining a local inflammatory site. In this study, we investigated neutrophil migration toward LNs in a context of inflammation induced by immunization of BALB/c mice with OVA emulsified in CFA. We demonstrated that neutrophils can enter LNs of OVA/CFA-immunized mice not only via lymphatic vessels but also from blood, across high endothelial venules. By adoptive transfer experiments, we showed that this influx was dependent on an inflammatory-state condition and previous neutrophil stimulation with OVA/anti-OVA immune complexes. Importantly, we have demonstrated that, in the migratory pattern to LNs, neutrophils used L-selectin and P-selectin glycoprotein ligand-1, macrophage-1 Ag and LFA-1 integrins, and CXCR4 to get access across high endothelial venules, whereas macrophage-1 Ag, LFA-1, and CXCR4 were involved in their trafficking through afferent lymphatics. Strikingly, we found that stimulation with immune complexes significantly upregulated the expression of sphingosine-1-phosphate receptor 4 on neutrophils, and that treatment with the sphingosine-1-phosphate agonist FTY720 altered neutrophil LN-homing ability. These findings summarized in this article disclose the molecular pattern that controls neutrophil recruitment to LNs.

Controlled release of sphingosine-1-phosphate agonist with gelatin hydrogels for macrophage recruitment.

The objective of this study is to design a drug delivery system (DDS) for the in vivo promotion of macrophage recruitment. As the drug, a water-insoluble agonist of sphingosine-1-phosphate type 1 receptor (SEW2871) was selected. SEW2871 (SEW) was water-solubilized by micelle formation with gelatin grafted by L-lactic acid oligomer. SEW micelles were mixed with gelatin, followed by dehydrothermal crosslinking of gelatin to obtain gelatin hydrogels incorporating SEW micelles. SEW was released from the hydrogels incorporating SEW micelles in vitro and in vivo. The water-solubilized SEW showed in vitro macrophage migration activity. When implanted into the back subcutis or the skin wound defect of mice, the hydrogel incorporating SEW micelles promoted macrophage migration toward the tissue around the implanted site to a significantly great extent compared with SEW-free hydrogel and that mixed with SEW micelles. The hydrogel is a promising DDS to enhance macrophage recruitment in vivo.

Sphingosine-1 phosphate and central nervous system.

The development of fingolimod, an unselective functional antagonist of the interactions between sphingosine 1 phosphate (S1P) and sphingosine 1 phosphate receptors (S1PRs), as the first oral therapy for multiple sclerosis (MS) has been a milestone. The parallel intensive research on the role of S1P, sphingosine kinases, and the five known S1PRs, their tissue distribution and expression in physiological and pathological conditions have led to a wide range of interesting findings. The initial focus of this research in the context of developing fingolimod as a treatment of MS has been on its immunological effects. The wide distribution and important roles of sphingosine, its metabolites, and their receptors in the central nervous system (CNS) in general, in myelin, and in all cell types of this organ have spurred interest to examine S1P and its five receptors in the brain as well. The present review will concentrate on the latter area and give a brief overview of what is known about S1P/S1PR interactions in the CNS in physiological and pathological conditions.

Cytokine storm plays a direct role in the morbidity and mortality from influenza virus infection and is chemically treatable with a single sphingosine-1-phosphate agonist molecule.

Cytokine storm defines a dysregulation of and an excessively exaggerated immune response most often accompanying selected viral infections and several autoimmune diseases. Newly emerging and re-emerging infections of the respiratory tract, especially influenza, SARS, and hantavirus post considerable medical problems. Their morbidities and mortalities are often a direct result of cytokine storm. This chapter visits primarily influenza virus infection and resultant cytokine storm. It provides the compelling evidence that illuminates cytokine storm in influenza pathogenesis and the clear findings that cytokine storm is chemically tractable by therapy directed toward sphingosine-1-phosphate receptor (S1PR) modulation, specifically S1P1R agonist therapy. The mechanism(s) of how S1P1R signaling works and the pathways involved are subjects of this review.

Ginsenoside compound K inhibits angiogenesis via regulation of sphingosine kinase-1 in human umbilical vein endothelial cells.

Ginsenoside compound K (CK) is a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer (Araliaceae), has long been used to treat against the development of cancer, inflammation, allergies, and diabetes. This study examined the anti-angiogenic properties of CK against sphingosine 1-phosphate (S1P)-induced cell migration via regulation of sphingosine kinase 1 (SPHK1) in human umbilical vein endothelial cells (HUVEC). Studies on S1P-induced cell migration, expression of SPHK1 and MMPs and analysis of sphingolipid metabolites by LC-MS/MS were examined after the treatment of CK (2.5, 5, 10 µg/mL) in HUVEC. S1P produced by SPHK1 is also involved in cell growth, migration, and protection of apoptosis; therefore, we sought to investigate whether ginsenosides are able to regulate SPHK1. For this purpose, we developed an inhibitory assay of SPHK1 activity and an analytical method for detection of S1P and other sphingolipid metabolites in HUVEC. Ginsenoside CK inhibited 100 nM S1P-induced cell migrations in a dose-dependent manner. Among tested ginsenosides, CK exclusively inhibited S1P production, SPHK1 activity and SPHK1 expression in HUVEC, whereas expression of the pro-apoptotic sphingolipids, sphingosine and ceramide, was increased in response to CK. The major subspecies of the increased ceramide was C24:0-ceramide. CK also disrupted the sphingolipid rheostat, which ultimately influences cell fate, and dose-dependently inhibited HUVEC migration by reducing expression of metalloproteinases (MMPs). Ginsenoside CK acts as a unique HUVEC migration inhibitor by regulating MMP expression, as well as the activity of SPHK1 and its related sphingolipid metabolites.