Sphingosine 1-phosphate Receptor Agonist Research Articles

An Efficient Scale-Up Synthesis of BMS-520, a Potent and Selective Isoxazole-Containing S1P1 Receptor Agonist

This article reports an efficient scale-up synthesis of 1-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylic acid (BMS-520), a potent and selective isoxazole-containing S1P1 receptor agonist. This process features a highly regioselective cycloaddition leading to a key intermediate, ethyl 3-phenyl-4-(trifluoromethyl)isoxazole-5-carboxylate, a chemo-selective hydrolysis of its regioisomers, as well as an improved method for 1,2,4-oxadiazole formation, relative to the original synthesis. The improved process was applied to the preparation of multiple batches of BMS-520 for preclinical toxicological studies.

Spingosine-1-phosphate receptor 1 agonist alleviates hypersensitivity pneumonitis induced by Methanosphaera stadtmanae

Abstract Hypersensitivity pneumonitis (HP) is characterized by the formation of B cell-rich tertiary lymphoid tissue (TLT) in the lung, and by a granulocytic response upon antigen rechallenge. Clinically, antigen avoidance is the only effective approach to manage HP symptoms and progression. Sphingosine-1-phosphate receptor 1 (S1PR1) regulates key mechanisms underlying the formation of TLTs such as lymphocyte trafficking and intercellular interactions. Given that TLTs are key to the antigen-specific response in the lung, we investigated the impact of an S1PR1 agonist on pulmonary TLTs accumulation and determined the effect of quantitative TLTs modulation on the granulocytic response to an antigen rechallenge. Experimental HP was induced in mice using intranasal instillations of an immunogenic archaea found in farm bioaerosol, Methanosphaera stadtmanae (MSS), for 3 weeks. After a 48 hours resting period, mice were treated for 7 days with the S1PR1 agonist, RP001 (1mg/kg/day), or its vehicle using osmotic pumps. Five days after treatment initiation, mice were either euthanized, rechallenged with saline or rechallenged with MSS. Mice were euthanized 48h later to quantify pulmonary TLTs and inflammatory cells. RP001 did not influence TLTs accumulation and lung inflammation prior to MSS rechallenge. After MSS rechallenge, RP001 reduced the accumulation of TLTs by 49% (p=0.02) and reduced neutrophil accumulation by 39% (p=0.002), when compared to vehicle. Thus, S1PR1 modulation, after the initiation of a HP-like disease, alleviated TLTs accumulation along with the neutrophilic response to an antigen rechallenge. Our results support the concept that S1PR1 modulation can interfere with mechanisms that sustain HP.

Ozanimod (RPC1063) is a potent sphingosine-1-phosphate receptor-1 (S1P1 ) and receptor-5 (S1P5 ) agonist with autoimmune disease-modifying activity.

Sphingosine1-phosphate (S1P) receptors mediate multiple events including lymphocyte trafficking, cardiac function, and endothelial barrier integrity. Stimulation of S1P1 receptors sequesters lymphocyte subsets in peripheral lymphoid organs, preventing their trafficking to inflamed tissue sites, modulating immunity. Targeting S1P receptors for treating autoimmune disease has been established in clinical studies with the non-selective S1P modulator, FTY720 (fingolimod, Gilenya™). The purpose of this study was to assess RPC1063 for its therapeutic utility in autoimmune diseases. The specificity and potency of RPC1063 (ozanimod) was evaluated for all five S1P receptors, and its effect on cell surface S1P1 receptor expression, was characterized in vitro. The oral pharmacokinetic (PK) parameters and pharmacodynamic effects were established in rodents, and its activity in three models of autoimmune disease (experimental autoimmune encephalitis, 2,4,6-trinitrobenzenesulfonic acid colitis and CD4(+) CD45RB(hi) T cell adoptive transfer colitis) was assessed. RPC1063 was specific for S1P1 and S1P5 receptors, induced S1P1 receptor internalization and induced a reversible reduction in circulating B and CCR7(+) T lymphocytes in vivo. RPC1063 showed high oral bioavailability and volume of distribution, and a circulatory half-life that supports once daily dosing. Oral RPC1063 reduced inflammation and disease parameters in all three autoimmune disease models. S1P receptor selectivity, favourable PK properties and efficacy in three distinct disease models supports the clinical development of RPC1063 for the treatment of relapsing multiple sclerosis and inflammatory bowel disease, differentiates RPC1063 from other S1P receptor agonists, and could result in improved safety outcomes in the clinic.

Endothelial Nogo-B regulates sphingolipid biosynthesis to promote pathological cardiac hypertrophy during chronic pressure overload.

We recently discovered that endothelial Nogo-B, a membrane protein of the ER, regulates vascular function by inhibiting the rate-limiting enzyme, serine palmitoyltransferase (SPT), in de novo sphingolipid biosynthesis. Here, we show that endothelium-derived sphingolipids, particularly sphingosine-1-phosphate (S1P), protect the heart from inflammation, fibrosis, and dysfunction following pressure overload and that Nogo-B regulates this paracrine process. SPT activity is upregulated in banded hearts in vivo as well as in TNF-α-activated endothelium in vitro, and loss of Nogo removes the brake on SPT, increasing local S1P production. Hence, mice lacking Nogo-B, systemically or specifically in the endothelium, are resistant to the onset of pathological cardiac hypertrophy. Furthermore, pharmacological inhibition of SPT with myriocin restores permeability, inflammation, and heart dysfunction in Nogo-A/B-deficient mice to WT levels, whereas SEW2871, an S1P1 receptor agonist, prevents myocardial permeability, inflammation, and dysfunction in WT banded mice. Our study identifies a critical role of endothelial sphingolipid biosynthesis and its regulation by Nogo-B in the development of pathological cardiac hypertrophy and proposes a potential therapeutic target for the attenuation or reversal of this clinical condition.

Novel S1P1 receptor agonists – Part 4: Alkylaminomethyl substituted aryl head groups

In a previous communication we reported on the discovery of alkylamino pyridine derivatives (e.g. 1) as a new class of potent, selective and efficacious S1P1 receptor (S1PR1) agonists. However, more detailed profiling revealed that this compound class is phototoxic in vitro. Here we describe a new class of potent S1PR1 agonists wherein the exocyclic nitrogen was moved away from the pyridine ring (e.g. 11c). Further structural modifications led to the identification of novel alkylaminomethyl substituted phenyl and thienyl derivatives as potent S1PR1 agonists. These new alkylaminomethyl aryl compounds showed no phototoxic potential. Based on their in vivo efficacy and ability to penetrate the brain, the 5-alkyl-aminomethyl thiophenes appeared to be the most interesting class. Potent and selective S1PR1 agonist 20e, for instance, maximally reduced the blood lymphocyte count (LC) for 24 h after oral administration of 10 mg/kg to rat and its brain concentrations reached >500 ng/g over 24 h.

Novel S1P1 receptor agonists – Part 5: From amino-to alkoxy-pyridines

In a previous communication we reported on the discovery of aminopyridine 1 as a potent, selective and orally active S1P1 receptor agonist. More detailed studies revealed that this compound is phototoxic in vitro. As a result of efforts aiming at eliminating this undesired property, a series of alkoxy substituted pyridine derivatives was discovered. The photo irritancy factor (PIF) of these alkoxy pyridines was significantly lower than the one of aminopyridine 1 and most compounds were not phototoxic. Focused SAR studies showed, that 2-, 3-, and 4-pyridine derivatives delivered highly potent S1P1 receptor agonists. While the 2-pyridines were clearly more selective against S1PR3, the corresponding 3- or 4-pyridine analogues showed significantly longer oral half-lives and as a consequence longer pharmacological duration of action after oral administration. One of the best compounds, cyclopentoxy-pyridine 45b lacked phototoxicity, showed EC50 values of 0.7 and 140 nM on S1PR1 and S1PR3, respectively, and maximally reduced the blood lymphocyte count for at least 24 h after oral administration of 10 mg/kg to Wistar rats.

Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1.

Apolipoprotein M (ApoM) transports sphingosine-1-phosphate (S1P) in plasma, and ApoM-deficient mice (Apom(-/-)) have ∼50% reduced plasma S1P levels. There are 5 known S1P receptors, and S1P induces adherens junction formation between endothelial cells through the S1P1 receptor, which in turn suppresses vascular leak. Increased vascular permeability is a hallmark of inflammation. The purpose of this study was to explore the relationships between vascular leakage in ApoM deficiency and S1P1 function in normal physiology and in inflammation. Vascular permeability in the lungs was assessed by accumulation of dextran molecules (70 kDa) and was increased ∼40% in Apom(-/-) mice compared to WT (C57Bl6/j) mice. Reconstitution of plasma ApoM/S1P or treatment with an S1P1 receptor agonist (SEW2871) rapidly reversed the vascular leakage to a level similar to that in WT mice, suggesting that it is caused by decreased plasma levels of S1P and reduced S1P1 stimulation. In a carrageenan-induced model of inflammation, Apom(-/-) mice had increased vascular leakage compared with that in WT mice. Adenoviral overexpression of ApoM in Apom(-/-) mice decreased the vascular leakage compared to adenoviral overexpression of green fluorescent protein. The study suggests that vascular leakage of albumin-sized particles in ApoM deficiency is S1P- and S1P1-dependent and this dependency exacerbates the response to inflammatory stimuli.-Christensen, P. M., Liu, C. H., Swendeman, S. L., Obinata, H., Qvortrup, K., Nielsen, L B., Hla, T., Di Lorenzo, A., Christoffersen, C. Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1.

Therapeutic Impact of Sphingosine 1-phosphate Receptor Signaling in Multiple Sclerosis.

Multiple sclerosis (MS) is a female predominant autoimmune demyelinating disease of central nervous system. The proper etiology is not clear. The existing therapies with interferon beta (Betaseron, Rebif), glatiramer acetate (copolymer 1, copaxone) are found to be promising for MS patients. The alpha-4 integrin antagonist monoclonal antibody Natalizumab has been found to decrease brain inflammation in relapsing-remitting MS via inhibition of alpha-4 beta- 1 integrinmediated mode of action of antigen -primed T cells to enter into central nervous system through blood brain barrier. The advancement of drug development introduced prospects of CD52 monoclonal antibody Alemtuzumab and CD20 monoclonal antibody Rituximab in MS therapy. The benefit versus risk ratios of these therapeutic monoclonal antibodies are currently under clinical trial. The ongoing researches demonstrated the importance of HMG-CoA reductase inhibitor statins, NF-κBp65 inhibitor NBD peptide, and antagonist of poly-ADP-ribose polymerase (PARP) in experimental autoimmune encephalomyelitis (EAE), animal model for MS. Recently, the clinical trials indicated the therapeutic prospect of G-protein coupled sphingosine 1-phosphate receptor (S1PR) in MS patients. Recent studies showed remyelination through selective activation of oligodendrocyte progenitor cells. In the context, role of S1PR-mediated signals following interaction with natural ligand S1P and agonist Fingolimod (FTY720) gain profound therapeutic importance in prevention of demyelination in MS brain. The S1PR agonist Fingolimod (FTY 720) has recently been approved by Food and Drug Administration for MS therapy. In the review, we provided an insight on S1PR mode of action in the aspect of treatment of autoimmune disorder, re-myelination and regeneration of axons in damaged central nervous system in multiple sclerosis.

Interfering with interferons

Sphingosine 1-phosphate receptor agonists suppress immunopathology by targeting the type I interferon receptor for degradation.

Therapeutic Potential of the Modulation of Sphingosine-1-Phosphate Receptors.

It is accepted that sphingolipids (SL) are not only structural lipids in cellular membranes, but also key regulators of different cell process. Sphingosine-1-phosphate (S1P) is a member of this family involved, inter alia, in cell migration, angiogenesis and cell proliferation processes, being able to play different intracellular and extracellular roles. When S1P is transported out of the cell, it binds S1P specific G protein-coupled receptors, which are mainly involved in the regulation of the immune, vascular and nervous systems. These effects account for the vast diversity of functions that arise from the activation of S1P receptors. Deregulation of S1P levels is correlated with several pathologies, such as autoimmune disorders and cancer. Consequently, the correct modulation of these receptors represents a valuable approach for the development of new therapeutic strategies. Along this line, the non-selective S1P receptor agonist fingolimod (FTY720) has been commercialized recently for the treatment of multiple sclerosis and several related S1P receptor modulators are ongoing clinical trials. However, despite the progress in this field, the biological functions of S1P receptors are not still well elucidated. For this reason, several studies are being developed in order to better understand the functions of these receptors, making use of new selective S1P receptor agonists and antagonists as pharmacological tools.

Effects of FTY720 on peripheral blood lymphocytes and graft infiltrating cells in a rat model of chronic renal allograft rejection

AimsChronic renal allograft loss is still an unsolved problem in kidney transplantation. We evaluated the impact of FTY720, a S1P receptor agonist, known to deplete lymphocytes from the peripheral blood by sequestering them into lymph nodes and Peyer's patches, on blood lymphocytes and graft infiltrating cells in a rat model of chronic real allograft rejection. MethodsLEW rats served as recipients for LEW.1U7B kidney grafts. All animals were treated with CsA (5mg/kg) for 10days after renal transplantation and monitored for kidney function, peripheral blood lymphocytes and graft infiltrating cells.In the intervention group (n=7) FTY720 therapy was started 7weeks post-KTx in a dose of 0.5mg/kg p. o. three times a week. ResultsIn the control group the survival of the rats was 9, 11, 18 and 4×24 weeks, in the intervention group 2×8, 9, 2×11, 18 and 20weeks. While in the intervention group the number of T- and B-lymphocytes in the peripheral blood was successfully reduced during FTY720 treatment, both groups showed significant amounts of T- and B-lymphocytes in the kidney grafts. Animals in both groups developed donor specific antibodies, extensive albuminuria and severe chronic changes in the grafts. ConclusionsFTY720 was highly effective to reduce T- and B-lymphocytes in the peripheral blood, but not effective in clearing their infiltration in the graft. Graft survival was not prolonged by FTY720 treatment starting late after kidney transplantation.

S1PR1-mediated IFNAR1 degradation modulates plasmacytoid dendritic cell interferon-α autoamplification

Blunting immunopathology without abolishing host defense is the foundation for safe and effective modulation of infectious and autoimmune diseases. Sphingosine 1-phosphate receptor 1 (S1PR1) agonists are effective in treating infectious and multiple autoimmune pathologies; however, mechanisms underlying their clinical efficacy are yet to be fully elucidated. Here, we uncover an unexpected mechanism of convergence between S1PR1 and interferon alpha receptor 1 (IFNAR1) signaling pathways. Activation of S1PR1 signaling by pharmacological tools or endogenous ligand sphingosine-1 phosphate (S1P) inhibits type 1 IFN responses that exacerbate numerous pathogenic conditions. Mechanistically, S1PR1 selectively suppresses the type I IFN autoamplification loop in plasmacytoid dendritic cells (pDCs), a specialized DC subset, for robust type I IFN release. S1PR1 agonist suppression is pertussis toxin-resistant, but inhibited by an S1PR1 C-terminal-derived transactivating transcriptional activator (Tat)-fusion peptide that blocks receptor internalization. S1PR1 agonist treatment accelerates turnover of IFNAR1, suppresses signal transducer and activator of transcription 1 (STAT1) phosphorylation, and down-modulates total STAT1 levels, thereby inactivating the autoamplification loop. Inhibition of S1P-S1PR1 signaling in vivo using the selective antagonist Ex26 significantly elevates IFN-α production in response to CpG-A. Thus, multiple lines of evidence demonstrate that S1PR1 signaling sets the sensitivity of pDC amplification of IFN responses, thereby blunting pathogenic immune responses. These data illustrate a lipid G-protein coupled receptor (GPCR)-IFNAR1 regulatory loop that balances effective and detrimental immune responses and elevated endogenous S1PR1 signaling. This mechanism will likely be advantageous in individuals subject to a range of inflammatory conditions.

Sphingosine 1-phospate differentially modulates maturation and function of human Langerhans-like cells

BackgroundAs mediators between innate and adaptive immune responses, Langerhans cells (LCs) are in the focus of recent investigations to determine their role in allergic inflammatory diseases like allergic contact dermatitis and atopic dermatitis. Sphingosine 1-phosphate (S1P) is a crucial lipid mediator in the skin and potentially interferes with LC homeostasis but also functional properties, such as cytokine release, migration and antigen-uptake which are considered to be key events in the initiation and maintenance of pathological disorders. ObjectiveHere, we used human Langerhans-like cells to study the influence of S1P-mediated signalling on LC maturation, cytokine release, migration and endocytosis. MethodsImmature Langerhans-like cells were generated from the human acute myeloid leukaemia cell line MUTZ-3 (MUTZ-LCs) and human primary monocytes (MoLCs). S1P receptor expression was determined by quantitative RT-PCR and western blotting. Expression of maturation markers were investigated by flow cytometry. The influence of S1P signalling on cytokine release was quantified by ELISA. Migration assays and FITC-dextran uptake in the presence of S1P, specific S1 P receptor agonists and antagonists as well as fingolimod (FTY720) were analysed through fluorescence microscopy and flow cytometry. ResultsS1P receptor protein expression was confirmed for S1P1, S1P2 and S1P4 in MUTZ-LCs and S1P1 and S1P2 in MoLCs. In mature cells S1P receptors were downregulated. S1P did not induce maturation in MUTZ-LCs, whereas in MoLCs CD83 and CD86 were slightly upregulated. IL-8 release of MUTZ-LCs matured in the presence of S1P was not altered, however, reduced IL-6 and IL-12p70 levels were observed in mature MoLCs. Interestingly, immature MUTZ-LCs revealed a significantly increased S1P-dependent migratory capacity, whereas CCL20 induced migration was significantly decreased in the presence of S1P. Furthermore, migratory capacity towards CCL21 in mature MUTZ-LCs but not MoLCs was significantly lower when cells were stimulated with S1P. S1P, FTY720 and specific S1P receptor agonists did not modulate the endocytotic capacity of immature MUTZ-LCs and MoLCs. These findings were further supported by testing specific antagonists of S1P1−4 in the absence or presence of S1P. ConclusionOur data demonstrate that S1P regulates key events of human LC maturation including cytokine release and migration. These findings are of particular importance when considering the potential use of S1P in inflammatory skin disorders.

Sphingosine-1-Phosphate/Sphingosine-1-Phosphate Receptor 2 Axis Can Promote Mouse and Human Primary Mast Cell Angiogenic Potential through Upregulation of Vascular Endothelial Growth Factor-A and Matrix Metalloproteinase-2.

Mast cells (MC) are present in most vascularized tissues around the vasculature likely exerting immunomodulatory functions. Endowed with diverse mediators, resident MC represent first-line fine-tuners of local microenvironment. Sphingosine-1-phosphate (S1P) functions as a pluripotent signaling sphingolipid metabolite in health and disease. S1P formation occurs at low levels in resting MC and is upregulated upon activation. Its export can result in type 2 S1P receptor- (S1PR2-) mediated stimulation of MC, further fueling inflammation. However, the role of S1PR2 ligation in proangiogenic vascular endothelial growth factor- (VEGF-) A and matrix metalloproteinase- (MMP-) 2 release from MC is unknown. Using a preclinical MC-dependent model of acute allergic responses and in vitro stimulated primary mouse bone marrow-derived MC (BMMC) or human primary skin MC, we report that S1P signaling resulted in substantial amount of VEGF-A release. Similar experiments using S1pr2-deficient mice or BMMC or selective S1P receptor agonists or antagonists demonstrated that S1P/S1PR2 ligation on MC is important for VEGF-A secretion. Further, we show that S1P stimulation triggered transcriptional upregulation of VEGF-A and MMP-2 mRNA in human but not in mouse MC. S1P exposure also triggered MMP-2 secretion from human MC. These studies identify a novel proangiogenic axis encompassing MC/S1P/S1PR2 likely relevant to inflammation.

AKP-11 - A Novel S1P1 Agonist with Favorable Safety Profile Attenuates Experimental Autoimmune Encephalomyelitis in Rat Model of Multiple Sclerosis.

Sphingosine-1-phosphate receptor 1 (S1P1) mediated regulation of lymphocyte egress from lymphoid organs is recognized as the mechanism of FTY720 (Fingolimod, Gilenya) efficacy in relapsing-remitting forms of multiple sclerosis (RRMS). In this study we describe a novel S1P1 agonist AKP-11, next generation of S1P1 agonist, with immunomodulatory activities in cell culture model and for therapeutic efficacy against an animal model of MS, i.e. experimental autoimmune encephalomyelitis (EAE) but without the adverse effects observed with FTY720. Like FTY720, AKP-11 bound to S1P1 is internalized and activates intracellular AKT and ERKs cellular signaling pathways. In contrast to FTY720, AKP-11 mediated S1P1 downregulation is independent of sphingosine kinase activity indicating it to be a direct agonist of S1P1. The S1P1 loss and inhibition of lymphocyte egress by FTY720 leads to lymphopenia. In comparison with FTY720, oral administration of AKP-11 caused milder and reversible lymphopenia while providing a similar degree of therapeutic efficacy in the EAE animal model. Consistent with the observed reversible lymphopenia with AKP-11, the S1P1 recycled back to cell membrane in AKP-11 treated cells following its withdrawal, but not with withdrawal of FTY720. Accordingly, a smaller degree of ubiquitination and proteolysis of S1P1 was observed in AKP-11 treated cells as compared to FTY720. Consistent with previous observations, FTY720 treatment is associated with adverse effects of bradycardia and lung vascular leaks in rodents, whereas AKP-11 treatment had undetectable effects on bradycardia and reduced lung vascular leaks as compared to FTY720. Taken together, the data documents that AKP-11 treatment cause milder and reversible lymphopenia with milder adverse effects while maintaining therapeutic efficacy similar to that observed with FTY720, thus indicating therapeutic potential of AKP-11 for treatment of MS and related autoimmune disorders.

Sphingosine-1-Phosphate Receptor-1 Selective Agonist Enhances Collateral Growth and Protects against Subsequent Stroke.

Background and PurposeCollateral growth after acute occlusion of an intracranial artery is triggered by increasing shear stress in preexisting collateral pathways. Recently, sphingosine-1-phosphate receptor-1 (S1PR1) on endothelial cells was reported to be essential in sensing fluid shear stress. Here, we evaluated the expression of S1PR1 in the hypoperfused mouse brain and investigated the effect of a selective S1PR1 agonist on leptomeningeal collateral growth and subsequent ischemic damage after focal ischemia.MethodsIn C57Bl/6 mice (n = 133) subjected to unilateral common carotid occlusion (CCAO) and sham surgery. The first series examined the time course of collateral growth, cell proliferation, and S1PR1 expression in the leptomeningeal arteries after CCAO. The second series examined the relationship between pharmacological regulation of S1PR1 and collateral growth of leptomeningeal anastomoses. Animals were randomly assigned to one of the following groups: LtCCAO and daily intraperitoneal (ip) injection for 7 days of an S1PR1 selective agonist (SEW2871, 5 mg/kg/day); sham surgery and daily ip injection for 7 days of SEW2871 after surgery; LtCCAO and daily ip injection for 7 days of SEW2871 and an S1PR1 inverse agonist (VPC23019, 0.5 mg/kg); LtCCAO and daily ip injection of DMSO for 7 days after surgery; and sham surgery and daily ip injection of DMSO for 7 days. Leptomeningeal anastomoses were visualized 14 days after LtCCAO by latex perfusion method, and a set of animals underwent subsequent permanent middle cerebral artery occlusion (pMCAO) 7days after the treatment termination. Neurological functions 1hour, 1, 4, and 7days and infarction volume 7days after pMCAO were evaluated.ResultsIn parallel with the increase in S1PR1 mRNA levels, S1PR1 expression colocalized with endothelial cell markers in the leptomeningeal arteries, increased markedly on the side of the CCAO, and peaked 7 days after CCAO. Mitotic cell numbers in the leptomeningeal arteries increased after CCAO. Administration of the S1PR1 selective agonist significantly increased cerebral blood flow (CBF) and the diameter of leptomeningeal collateral vessels (42.9 ± 2.6 μm) compared with the controls (27.6 ± 5.7 μm; P < 0.01). S1PR1 inverse agonist administration diminished the effect of the S1PR1 agonist (P < 0.001). After pMCAO, S1PR1 agonist pretreated animals showed significantly smaller infarct volume (17.5% ± 4.0% vs. 7.7% ± 4.0%, P < 0.01) and better functional recovery than vehicle-treated controls.ConclusionsThese results suggest that S1PR1 is one of the principal regulators of leptomeningeal collateral recruitment at the site of increased shear stress and provide evidence that an S1PR1 selective agonist has a role in promoting collateral growth and preventing of ischemic damage and neurological dysfunction after subsequent stroke in patients with intracranial major artery stenosis or occlusion.

Abstract 130: Sphingosine-1-Phosphate Signaling Plays a Role in High Blood Pressure Programmed by Intrauterine Growth Restriction in Mouse

Intrauterine growth restriction (IUGR) is a risk factor for hypertension and cardiovascular (CV) disease in later life, but the underlying mechanisms remain unclear. The bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P) is critically involved in CV development in the fetus, and plays a significant role in the regulation of CV health in adulthood. S1P receptor (S1PR) type 1, 2 and 3 are widely expressed in CV system which S1PR1 has a protective role against kidney injury, while S1PR3 is involved in controlling BP. Yet, the contribution of S1P on BP in IUGR is unknown. In the present studies, we tested the hypothesis that IUGR alters renal S1P receptors expression during- and post-nephrogenesis, which contributes to high BP in male IUGR mouse. C57bl/6J mice underwent sham or reduced uterine perfusion (RUP) at day 13 of gestation with delivery at full term. IUGR offspring (from RUP dam) had a lower birth weight than control (p&lt;0.05). Kidneys were isolated from 2 day old male pups or adult 24 week old male control and IUGR. S1PR3 protein expression was increased in 2 day old IUGR kidneys (2.4 fold vs control, N=3, p&lt; 0.01). At 24 weeks of age, S1PR3 mRNA levels were increased (1.2 fold vs control, N=4, p&lt; 0.05) whereas S1PR3 protein levels were decreased (0.75 fold vs control, N=4, p&lt; 0.05) in IUGR kidneys. mRNA and protein expression levels of S1PR1 and S1PR2 were not different between control and IUGR kidneys. Finally, we assessed the role of S1PRs agonist on BP of IUGR. Male IUGR offspring had a significantly higher BP compared to male control via carotid catheter in the conscious state (control: 112.1±2.1, IUGR: 125.0±3.7 mmHg; N=7, P &lt;0.05). Acute administration of FTY720 (1 mg/kgBW i.p, Fingomod), a S1P receptor type 1, 3 agonist did not significantly alter BP in control (106.0 ± 5.7 mmHg) but significantly decreased BP in IUGR (105.7±2.3 mmHg, p&lt; 0.05). A dose response to FTY720 (10 mg/kgBW) decreased BP in both control (94.0±2.0 mmHg, p&lt; 0.05) and IUGR (99.3±2.3 mmHg, p&lt; 0.05). Together our data suggest that IUGR programs an alteration of renal S1PR3 expression in both during- and post-nephrogenesis thereby contributing to an increase in sensitivity to S1PRs agonist. Thus, S1P signaling is a putative mechanism underlying the hypertension of IUGR offspring.

Small Molecules in the Treatment of Psoriasis.

Preclinical Research Psoriasis is an inflammatory systemic skin disease that affects various parts of the body requiring long-term management due to its chronic nature. Available treatment options include topical, systemic or biological therapies, which have long-term limitations associated to toxicity, tolerability and risk for adverse effects requiring its intermittent use and close monitoring. Small molecules modulate proinflammatory cytokines, selectively inhibit signaling pathways and showing potential to treat inflammatory diseases in patients not responding to conventional treatments. Presently, small molecules available are phosphodiesterase 4 inhibitors or Janus kinase inhibitors. Other small molecules under development for psoriasis include fumaric acid esters, amygdalin analogs, protein kinase C inhibitors, mitogen-activated protein kinase inhibitors, spleen protein kinase inhibitors, other tyrosine kinase inhibitors, sphingosine 1-phosphate receptor agonists, and A3 adenosine receptor agonists. These new treatment options represent important advances in the development of specific drugs to respond to the goals of treatment and improve patient quality of life.

Sphingosine-1-phosphate receptor 1 agonism attenuates lung ischemia-reperfusion injury.

Outcomes for lung transplantation are the worst of any solid organ, and ischemia-reperfusion injury (IRI) limits both short- and long-term outcomes. Presently no therapeutic agents are available to prevent IRI. Sphingosine 1-phosphate (S1P) modulates immune function through binding to a set of G protein-coupled receptors (S1PR1-5). Although S1P has been shown to attenuate lung IRI, the S1P receptors responsible for protection have not been defined. The present study tests the hypothesis that protection from lung IRI is primarily mediated through S1PR1 activation. Mice were treated with either vehicle, FTY720 (a nonselective S1P receptor agonist), or VPC01091 (a selective S1PR1 agonist and S1PR3 antagonist) before left lung IR. Function, vascular permeability, cytokine expression, neutrophil infiltration, and myeloperoxidase levels were measured in lungs. After IR, both FTY720 and VPC01091 significantly improved lung function (reduced pulmonary artery pressure and increased pulmonary compliance) vs. vehicle control. In addition, FTY720 and VPC01091 significantly reduced vascular permeability, expression of proinflammatory cytokines (IL-6, IL-17, IL-12/IL-23 p40, CC chemokine ligand-2, and TNF-α), myeloperoxidase levels, and neutrophil infiltration compared with control. No significant differences were observed between VPC01091 and FTY720 treatment groups. VPC01091 did not significantly affect elevated invariant natural killer T cell infiltration after IR, and administration of an S1PR1 antagonist reversed VPC01091-mediated protection after IR. In conclusion, VPC01091 and FTY720 provide comparable protection from lung injury and dysfunction after IR. These findings suggest that S1P-mediated protection from IRI is mediated by S1PR1 activation, independent of S1PR3, and that selective S1PR1 agonists may provide a novel therapeutic strategy to prevent lung IRI.

FTY720 Phosphate Activates Sphingosine-1-Phosphate Receptor 2 and Selectively Couples to Gα12/13/Rho/ROCK to Induce Myofibroblast Contraction.

FTY720 phosphate (FTY720-P; 2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol, monodihydrogen phosphate ester) is a nonselective sphingosine-1-phosphate (S1P) receptor agonist thought to be devoid of activity at the S1P2 receptor subtype. However, we have recently shown that FTY720-P displays significant S1P2 receptor agonist activity in recombinant cells and fibroblasts expressing endogenous S1P2 receptors. To elucidate the S1P2-dependent signaling pathways that were activated by FTY720-P, we employed second messenger assays and impedance-based assays in combination with pharmacological and small interfering RNA-based pathway inhibition in recombinant Chinese hamster ovary (CHO)-S1P2 cells as well as human lung myofibroblasts generated in vitro. In CHO-S1P2 cells, FTY720-P did not modulate cAMP or calcium levels. However, reporter-gene assays, impedance-based assays with a selective Rho-associated kinase (ROCK) inhibitor, Gα12/13 knockdown and activated Rho-pull-down assays demonstrated that FTY720-P potently activated Gα12/13/Rho/ROCK signaling. S1P similarly activated Gα12/13/Rho/ROCK signaling via S1P2 receptors, whereas the two selective S1P1 receptor agonists (Z,Z)-5-(3-chloro-4-[(2R)-2,3-dihydroxy-propoxy]-benzylidene)-2-propylimino-3-o-tolyl-thiazolidin-4-one (ponesimond) and 5-[4-phenyl-5-(trifluoromethyl)thiophen-2-yl]-3-[3-(trifluoromethyl)phenyl]1,2,4-oxadiazole (SEW2871) were inactive. In lung myofibroblasts, which mainly expressed the S1P2 receptor subtype, we showed that FTY720-P selectively activated the Gα12/13/Rho/ROCK pathway via the S1P2 receptor. Moreover, the activation of the Gα12/13/Rho/ROCK pathway in myofibroblasts by FTY720-P caused potent myofibroblast contraction similar to that induced by the natural ligand S1P. Thus, complementing second messenger assays with unbiased label-free assays or phenotypic assays in native expression systems can uncover activation of additional pathways, such as Gα12/13/Rho/ROCK signaling.