Names | |
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Preferred IUPAC name (2S,3R,4E)-2-Amino-3-hydroxyoctadec-4-en-1-yl dihydrogen phosphate | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.164.436 |
KEGG | |
MeSH | sphingosine+1-phosphate |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C18H38NO5P | |
Molar mass | 379.472 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Sphingosine-1-phosphate (S1P) is a signaling sphingolipid, also known as lysosphingolipid. It is also referred to as a bioactive lipid mediator. Sphingolipids at large form a class of lipids characterized by a particular aliphatic aminoalcohol, which is sphingosine.
S1P is formed from ceramide, [1] which is composed of a sphingosine and a fatty acid. Ceramidase, an enzyme primarily present in plasma membrane, will convert ceramide to sphingosine. [1] Sphingosine is then phosphorylated by sphingosine kinase (SK) isoenzymes. [2] There are two identified mammalian isoenzymes, SK1 and SK2. [3] [4] [5] [6] These two enzymes have different tissue distribution. SK1 is highly expressed in spleen, lung and leukocytes, [3] while SK2 is highly expressed in liver and kidney. [3] SK2 is located mainly in the mitochondria, nucleus and the endoplasmic reticulum whereas SK1 is mainly located in cytoplasm and the cell membrane. [7] [8] [9]
S1P can be dephosphorylated to sphingosine by sphingosine phosphatases and can be irreversibly degraded by an enzyme, sphingosine phosphate lyase.
S1P is a blood borne lipid mediator, in particular in association with lipoproteins such as high density lipoprotein (HDL). [10] It is less abundant in tissue fluids. This is referred to as the S1P gradient, which seems to have biological significance in immune cell trafficking.
Originally thought as an intracellular second messenger, it was discovered to be an extracellular ligand for G protein-coupled receptor S1PR1 in 1998. It is now known that sphingosine-1-phosphate receptors (S1P receptors) are members of the lysophospholipid receptor family. There are five described to date. Most of the biological effects of S1P are mediated by signaling through the cell surface receptors.
Although S1P is of importance in the entire human body, it is a major regulator of vascular and immune systems, orchestrating how immune cells migrate within the arterial wall. [11] In addition, it might be relevant in the skin. In the vascular system, S1P regulates angiogenesis, vascular stability, and permeability. In the immune system, it is now recognized as a major regulator of trafficking of T- and B-cells. S1P interaction with its receptor S1PR1 is needed for the egress of immune cells from the lymphoid organs (such as thymus and lymph nodes) into the lymphatic vessels. Inhibition of S1P receptors was shown to be critical for immunomodulation. S1P has also been shown to directly suppress TLR mediated immune response from T cells. [12]
A research team, led by a scientist at Weill Cornell Medical College, has discovered that red blood cells perform a second vital function: angiogenesis. Given its role in creating new blood vessels, scientists recognize S1P as vital to human health — and a player in some diseases, such as cancer. And although S1P is known to be blood borne, no one realized until this study that S1P is supplied by red blood cells to control blood vessel growth.
The levels of S1P (in a range of 5–40 μmol/L) are 5 to 10 times up-regulated in ovarian cancer patients' ascites. S1P at this physiological concentration stimulates migration and invasion of epithelial ovarian cancer cells but inhibits migration of normal ovarian surface epithelial cells. [13] Most (more than 90%) ovarian cancers arise from the epithelium of the ovary. Therefore, extracellular S1P could have an important role in cancer progression by promoting migration of epithelial ovarian cancer cells.
Ozonization of human blood is associated with increased concentrations of S1P in the plasma. [14]
In addition, S1P modulates the proliferation of skin cells. This in particular applies to keratinocytes [15] while fibroblasts are not addressed in this way, apart from cell growth and differentiation. While S1P suppresses epidermal proliferation as the glucocorticoids do, it differs from them in so far, as proliferation of dermal fibroblasts is not reduced. In fact, S1P even activates fibroblast-derived extracellular matrix protein production.
Administration of S1P has been shown to protect oocytes from chemotherapeutic agents in vitro, [16] [17] [18] as well as in vivo from chemotherapeutic and radiation therapies. [16] [19] [20] [21] which otherwise induce apoptosis of the cells. S1P has protected ovarian tissue xenografts in SCID mouse models from radiation induced atresia. [21] In animal models these protected oocytes have been used to produce healthy live young. [19] [22] Radiotherapies and chemotherapies can cause apoptosis of ovarian follicles, causing premature ovarian failure, [23] and so S1P is of great interest in fertility preservation. [24] However, its mechanism of inhibiting the sphingomyelin apoptotic pathway may also interfere with the apoptosis action of chemotherapy drugs. [25]
Due to the hyperproliferative action against epidermal cells, S1P has been considered as an active pharmaceutical ingredient for hyperproliferative skin diseases, in particular, psoriasis vulgaris and acne vulgaris.[ citation needed ]
Although S1P is active at very low concentrations, bioavailability of the compound in human skin is a concern. Therefore, a topical formulation based on specific drug carriers has been considered inevitable.[ citation needed ]
Lpath Inc has produced and optimized a monoclonal anti-S1P antibody (Sphingomab). Sphingomab can absorb S1P from the extracellular fluid, thereby lowering the effective concentration of S1P.[ citation needed ]
Sonepcizumab is an experimental anti-S1P monoclonal antibody that has had a phase II clinical trial for renal cell carcinoma. [26] Sonepcizumab (LT1009) as ASONEP (for intravenous injection) has been studied for solid tumours. [27] As iSONEP, a formulation for intravitreal injection, it has been studied for age-related macular degeneration. [28]
There are 5 types of Sphingosine-1-phosphate receptor.
The drug fingolimod (FTY720), which agonizes the S1P receptor, [29] prevents autoimmune lymphocytes from moving from the lymphoid organs into the central nervous system. It has been shown in phase III clinical trials to reduce relapses and improve other outcomes in multiple sclerosis. [30] [31] S1P, as well as FTY720, has been shown to have anti-inflammatory properties at low concentrations and prevent monocyte:endothelial interactions in aorta, possibly through the S1P1 receptor. [32] [33] The S1P receptor agonist etrasimod has been shown to induce remission in patient with ulcerative colitis. [34]
ONO-4641 (a drug of Ono Pharmaceutical Co., Ltd.) is a sphingosine-1-phosphate (S1P) receptor agonist which keeps lymphocytes in lymph nodes and thereby inhibits the infiltration of lymphocytes into lesions. The compound is therefore expected to be a drug for the treatment of auto-immune diseases such as multiple sclerosis, which is regarded as an intractable disease.[ citation needed ]
Ozanimod is an agonist of the S1P1 and S1P5 receptors. [35] and has been studied for various forms of multiple sclerosis. [36]
In biochemistry, a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. This process is known as phosphorylation, where the high-energy ATP molecule donates a phosphate group to the substrate molecule. As a result, kinase produces a phosphorylated substrate and ADP. Conversely, it is referred to as dephosphorylation when the phosphorylated substrate donates a phosphate group and ADP gains a phosphate group. These two processes, phosphorylation and dephosphorylation, occur four times during glycolysis.
Sphingolipids are a class of lipids containing a backbone of sphingoid bases, which are a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sphinx because of their enigmatic nature. These compounds play important roles in signal transduction and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue. A sphingolipid with a terminal hydroxyl group is a ceramide. Other common groups bonded to the terminal oxygen atom include phosphocholine, yielding a sphingomyelin, and various sugar monomers or dimers, yielding cerebrosides and globosides, respectively. Cerebrosides and globosides are collectively known as glycosphingolipids.
Fingolimod, sold under the brand name Gilenya, is an immunomodulating medication, used for the treatment of multiple sclerosis. Fingolimod is a sphingosine-1-phosphate receptor modulator, which sequesters lymphocytes in lymph nodes, preventing them from contributing to an autoimmune reaction. It has been reported to reduce the rate of relapses in relapsing-remitting multiple sclerosis by approximately one-half over a two-year period.
Sphingosine kinase (SphK) is a conserved lipid kinase that catalyzes formation sphingosine-1-phosphate (S1P) from the precursor sphingolipid sphingosine. Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate, are lipid second messengers involved in diverse cellular processes. There are two forms of SphK, SphK1 and SphK2. SphK1 is found in the cytosol of eukaryotic cells, and migrates to the plasma membrane upon activation. SphK2 is localized to the nucleus.
Lipid signaling, broadly defined, refers to any biological cell signaling event involving a lipid messenger that binds a protein target, such as a receptor, kinase or phosphatase, which in turn mediate the effects of these lipids on specific cellular responses. Lipid signaling is thought to be qualitatively different from other classical signaling paradigms because lipids can freely diffuse through membranes. One consequence of this is that lipid messengers cannot be stored in vesicles prior to release and so are often biosynthesized "on demand" at their intended site of action. As such, many lipid signaling molecules cannot circulate freely in solution but, rather, exist bound to special carrier proteins in serum.
Sphingosine kinase 1 is an enzyme that in humans is encoded by the SPHK1 gene.
Sphingosine-1-phosphate receptor 1, also known as endothelial differentiation gene 1 (EDG1) is a protein that in humans is encoded by the S1PR1 gene. S1PR1 is a G-protein-coupled receptor which binds the bioactive signaling molecule sphingosine 1-phosphate (S1P). S1PR1 belongs to a sphingosine-1-phosphate receptor subfamily comprising five members (S1PR1-5). S1PR1 was originally identified as an abundant transcript in endothelial cells and it has an important role in regulating endothelial cell cytoskeletal structure, migration, capillary-like network formation and vascular maturation. In addition, S1PR1 signaling is important in the regulation of lymphocyte maturation, migration and trafficking.
CD69 is a human transmembrane C-Type lectin protein encoded by the CD69 gene. It is an early activation marker that is expressed in hematopoietic stem cells, T cells, and many other cell types in the immune system. It is also implicated in T cell differentiation as well as lymphocyte retention in lymphoid organs.
Sphingosine-1-phosphate receptor 3 also known as S1PR3 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate (S1P). Hence this receptor is also known as S1P3.
Sphingosine-1-phosphate receptor 4 also known as S1PR4 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate (S1P). Hence this receptor is also known as S1P4.
Sphingosine-1-phosphate receptor 2, also known as S1PR2 or S1P2, is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate (S1P).
4-Deoxypyridoxine is a vitamin B6 antagonist. It may be toxic to developing embryos since it can have negative effects on collagen and elastin during development. The presence of this compound can produce vitamin B6 deficiency, which suppresses the immune system. 4-Deoxypyridoxine lowers vitamin B6 concentration by competitively inhibiting some of the enzymes necessary for the regeneration of vitamin B6. The related immunosuppression can be beneficial in animal models of Trichinella spiralis infections. 4-Deoxypyridoxine has also been described as an inhibitor of sphingosine-1-phosphate lyase. The inhibition of sphingosine-1-phosphate lyase by 4-deoxypyridoxine has been shown to prevent cell death of ex vivo animal pancreatic islets. The use of 4-deoxypyridoxine to prevent stress-induced apoptosis is suggest that the compound, as well as other inhibitors of sphingosine-1-phosphate lyase, could be used to increase the viability of donor pancreatic tissue in the treatment of diabetes.
Safingol is a lyso-sphingolipid protein kinase inhibitor. It has the molecular formula C18H39NO2 and is a colorless solid. Medicinally, safingol has demonstrated promising anticancer potential as a modulator of multi-drug resistance and as an inducer of necrosis. The administration of safingol alone has not been shown to exert a significant effect on tumor cell growth. However, preclinical and clinical studies have shown that combining safingol with conventional chemotherapy agents such as fenretinide, vinblastine, irinotecan and mitomycin C can dramatically potentiate their antitumor effects. In phase I clinical trials, it was found to be safe to co-administer with cisplatin, but caused reversible dose-dependent hepatotoxicity.
Sphingosine kinase 2 is a protein that in humans is encoded by the SPHK2 gene.
The sphingosine-1-phosphate receptors are a class of G protein-coupled receptors that are targets of the lipid signalling molecule Sphingosine-1-phosphate (S1P). They are divided into five subtypes: S1PR1, S1PR2, S1PR3, S1PR4 and S1PR5.
Sarah Spiegel is professor and chair of the Department of Biochemistry and Molecular Biology at Virginia Commonwealth University (VCU). In the mid-1990s she discovered the sphingosine-1-phosphate (S1P) molecule, a lipid which has been identified as a signaler for the spread of cancer, inflammation, and cardiovascular disease. Her research continues to focus on S1P.
Ozanimod, sold under the brand name Zeposia, is an immunomodulatory medication for the treatment of relapsing multiple sclerosis and ulcerative colitis. It acts as a sphingosine-1-phosphate receptor (S1PR) agonist, sequestering lymphocytes to peripheral lymphoid organs and away from their sites of chronic inflammation.
Sphingosine-1-phosphate receptor modulators are a class of drugs used as immunomodulators, most notably in cases of multiple sclerosis.
Cells destined for apoptosis release molecules referred to as find-me signals. These signal molecules are used to attract phagocytes which engulf and eliminate damaged cells. Find-me signals are typically released by the apoptotic cells while the cell membrane remains intact. This ensures that the phagocytic cells are able to remove the dying cells before their membranes are compromised. A leaky membrane leads to secondary necrosis which may cause additional inflammation, therefore, it is best to remove dying cells before this occurs. One cell is capable of releasing multiple find-me signals. Should a cell lack the ability to release its find-me signal, other cells may release additional find-me signals to overcome the discrepancy.
Cell extrusion, discovered in 2001, is a process conserved in epithelial from humans to sea sponge to seamlessly remove unwanted or dying cells while maintaining the integrity of the epithelial barrier. If cells were to die without extrusion, gaps would be created, compromising the epithelia's function. While cell targeted to die by apoptotic stimuli extrude to prevent gaps from forming, most cells die as a result of extruding live cells. To maintain epithelial cell number homeostasis, live cells extrude when they become too crowded.