1-磷酸鞘氨醇受体

1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)对动脉粥样硬化等心血管疾病的发生发展具有重要作用。最近研究发现S1P在不同细胞发挥的生物学效应由其受体(sphingosine-1-phosphate receptor,S1PR)介导,以S1PR及其信号机制为基础的研究及治疗策略成为新的研究热点。本文主要综述S1PR的功能、信号通路及对心血管疾病的影响,为心血管疾病的预防和诊疗提供新的靶点。     

鞘氨醇-1-磷酸与免疫细胞的调节

鞘氨醇-1-磷酸（sphingosine-1 phosphate,S1P）是来源于鞘脂代谢途径的多效性信号分子,其代谢受到多种因素调控。S1P由细胞内的鞘氨醇激酶（sphingosine kinases,SphKs）催化鞘氨醇的磷酸化而合成,可通过转运蛋白释放至细胞外。S1P可通过在胞外结合其特异性G蛋白偶联受体及胞内作用而调节多种重要生物学效应。作为细胞外介质和细胞内信使,S1P在免疫系统中也发挥重要的调节作用。S1P参与免疫细胞的迁移、增殖、分化及死亡细胞清除等过程。本文对S1P的代谢以及其对于免疫细胞的调节作用进行综述。     

鞘氨醇激酶-磷酸鞘氨醇轴在血管生成相关性疾病中的作用

血管生成是指在原有血管的基础上形成新血管的过程.病理性血管生成是癌症、心血管类疾病和视网膜病变等一系列疾病的标志.1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)是一种信号脂质,由鞘氨醇激酶(sphingosine kinases,SPHK)合成,通过5种G蛋白偶联受体(sphingosine-...     

1- 磷酸鞘氨醇受体调节剂的研发现状

1- 磷酸鞘氨醇（S1P）具有多种生物学功能,S1P 受体（S1PR）调节剂可以用于治疗多种免疫性疾病。芬戈莫德是首个上市的 S1PR 调节剂,用于治疗多发性硬化症（MS）,2015 年销售额达到27 亿美元。药渡网数据显示：目前全球有14 个S1PR 调节剂进入临床, 适应证包括MS、银屑病、类风湿性关节炎和炎症性肠病等。国内目前针对S1PR 靶点的药物有1 个新药奥芬米洛已获批临床,另1 个 新药CBP-307 处于临床在审评阶段。简介S1PR 的生物学功能和S1PR 调节剂在国内外的开发情况,为靶向S1PR 的药物开发提供参考。     

鞘氨醇-1-磷酸的定量测定——一种新的竞争性结合方法

鞘氨醇-1-磷酸（SPP）是重要的细胞第二信使,影响细胞的生长和死亡.通过培养和收集转染SPP受体-EDG-1的HEK293细胞,与标记及非标记SPP共孵育,利用它们与HEK293细胞的竞争性结合,测定细胞、血清和组织中SPP含量.该法无需特殊仪器,可以测到皮摩尔水平的低含量,批间差异小于15%（6次）.     

鞘氨醇激酶1和1-磷酸鞘氨醇受体2在癫痫大鼠海马组织中表达的变化*

目的:检测鞘氨醇激酶1 (SphK1)和1-磷酸鞘氨醇受体2 (S1PR2) 在癫痫大鼠海马中的表达,探讨SphK1和S1PR2在癫痫中的作用机制。方法:成年雄性SD大鼠108只,随机分为对照(Control)组(n=48)和癫痫(PILO)组(n=60)。癫痫组腹腔注射氯化锂(127 mg/kg),18～20 h后注射匹罗卡品,首剂量为30 mg/kg,发作＜IV级的大鼠重复注射匹罗卡品(10 mg/kg);对照组给予等剂量的生理盐水代替匹罗卡品。根据造模后观察时间和行为学改变,随机分为3个大组,6个亚组:急性期组(E6 h、E1 d、E3 d)、潜伏期组(E7 d)和慢性期组(E30 d、E56 d),每个亚组中对照大鼠和癫痫大鼠各8只。每组取4只大鼠麻醉取海马,另4只取大脑组织。运用Western blot检测SphK1、S1PR2在大鼠海马组织中的表达变化,免疫荧光检测星形胶质细胞活化增生情况及SphK1、S1PR2在星形胶质细胞中的定位表达。结果:与Control组比较,SphK1在造模后急性期(E3 d)、潜伏期(E7 d)和慢性期(E30 d、E56 d)海马中的表达均明显升高(P＜0.05或P＜0.01);S1PR2在急性期(E3 d)、潜伏期(E7 d)和慢性期(E30 d、E56 d)海马组织中的表达均明显下降(P＜0.05或P＜0.01);癫痫大鼠(E7 d)海马星形胶质细胞活化、增生明显(P＜0.05),SphK1和S1PR2在E7d的表达到位为海马星形胶质细胞中。结论:SphK1和S1PR2可能通过调控海马星形胶质细胞活化增生和影响神经元兴奋性参与了癫痫的发病。     

脂质活性信号分子鞘氨醇-1-磷酸及其生物学特性

鞘氨醇-1-磷酸(sphingosine-1-phosphate,S1P)是目前颇受关注的脂质信号分子.体内S1P主要由红细胞内鞘氨醇激酶催化鞘氨醇合成,后经由ATP结合盒式转运子释放入血浆.血浆S1P超过半数存在于高密度脂蛋白和血清白蛋白上.S1P可通过直接胞内作用和激活其特异性G蛋白偶联受体产生多种重要生物学效应.S1P1-5型受体在体内各类型组织和细胞表达水平不同,参与包括细胞增殖、存活、迁移等多种生物学过程.     

1-磷酸鞘氨醇对豚鼠心室肌动作电位和收缩力的影响

目的：研究1-磷酸鞘氨醇（S1P）对豚鼠心室肌动作电位（AP）和心肌收缩力（CF）的影响。方法：实验采用标准玻璃微电极细胞内记录技术记录心室肌细胞动作电位（AP）肌力换能器记录心肌收缩力（CF）。结果：①应用0．1μmol／LS1P后心室肌动作电位幅度（APA）和时程（APD）与应用SIP前比较差异无显著性,而应用1．0μmol／LS1P,10μmol／LS1P后心室肌动作电位的幅度（APA）与应用S1P前比较明显降低而动作电位的时程（APD）与应用S1P前比较明显延长（P〈0．01）。②应用1．0μmol／LS1P和10μmol／LSIP后心室肌的CF与给药前相比明显增强（P〈0．01）,应用0．1μmol／LS1P后心室肌的CF与给药前比较差异无显著性（P〉0．05）。而加入S1P特异性G蛋白耦联内皮细胞分化基因（EDG）受体阻断剂苏拉明后,S1P的上述作用与给药前比较差异无显著性（P〉0．05）。结论：S1P可以降低心室肌动作电位幅值延长动作电住时程,增加心室肌收缩力,并且是通过其特异性的G蛋白耦联内皮细胞分化基因（EDG）受体介导而产生这些作用,有一定的剂量依赖性.     

植物体内的鞘氨醇-1-磷酸(S1P)

鞘氨醇-1-磷酸（S1P）在植物体内也可作为一种信号分子参与ABA介导的保卫细胞信号转导过程,这一途径和异三聚体G蛋白相耦联。文章对此问题的研究进展作了介绍。     

鞘氨醇激酶活性测定方法的建立及其初步应用

目的:建立生物样品中鞘氨醇激酶(SPK)活性和1-磷酸鞘氨醇(S1P)含量的测定方法.方法:用Flag标记的SPK基因表达载体转染ECV304细胞,用Western blot方法检测转染后SPK基因的表达,用酶促反应、同住素掺入和薄层层析的方法检测SPK的活性.提取细胞或组织的S1P,碱性磷酸酶消化去除磷酸根,然后利用SPK的催化活性和同位素标记的方法对S1P进行定量.结果:转染基因后细胞的SPK表达明显升高,活性显著增强,细胞内S1P的含量也明显增多.肝细胞生长因子(HGF)刺激能增强ECV304细胞SPK的活性和细胞内S1P水平.结论:建立了SPK活性和S1P含量的测定方法.     

Sphingosine-1-phosphate signaling controlling osteoclasts and bone homeostasis

Bone is a dynamic organ that is continuously turned over during growth, even in adults. During bone remodeling, homeostasis is regulated by the balance between bone formation by osteoblasts and bone resorption by osteoclasts. However, in pathological conditions such as osteoporosis, osteopetrosis, arthritic joint destruction, and bone metastasis, this equilibrium is disrupted. Since osteoclasts are excessively activated in osteolytic diseases, the inhibition of osteoclast function has been a major therapeutic strategy. It has recently been demonstrated that sphingosine-1-phosphate (S1P), a biologically active lysophospholipid that is enriched in blood, controls the trafficking of osteoclast precursors between the circulation and bone marrow cavities via G protein-coupled receptors, S1PRs. While S1PR1 mediates chemoattraction toward S1P in bone marrow, where S1P concentration is low, S1PR2 mediates chemorepulsion in blood, where the S1P concentration is high. The regulation of precursor recruitment may represent a novel therapeutic strategy for controlling osteoclast-dependent bone remodeling. By means of intravital multiphoton imaging of bone tissues, we have recently revealed that the reciprocal action of S1P controls the migration of osteoclast precursors between bone tissues and blood stream. Imaging technologies have enabled us to visualize the in situ behaviors of different cell types in intact tissues. In this review we also discuss future perspectives on this new method in the field of bone biology and medical sciences in general. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.     

Sphingosine-1-phosphate: dual messenger functions

The sphingolipid metabolite sphingosine-1-phosphate (S1P) is a serum-borne lipid that regulates many vital cellular processes. S1P is the ligand of a family of five specific G protein-coupled receptors that are differentially expressed in different tissues and regulate diverse cellular actions. Much less is known of the intracellular actions of S1P. It has been suggested that S1P may also function as an intracellular second messenger to regulate calcium mobilization, cell growth and suppression of apoptosis in response to a variety of extracellular stimuli. Dissecting the dual actions and identification of intracellular targets of S1P has been challenging, but there is ample evidence to suggest that the balance between S1P and ceramide and/or sphingosine levels in cells is an important determinant of cell fate.     

Sphingosine-1-phosphate signaling in vasculogenesis and angiogenesis

Blood vessels either form de novo through the process of vasculogenesis or through angiogenesis that involves the sprouting and proliferation of endothelial cells in pre-existing blood vessels. A complex interactive network of signaling cascades downstream from at least three of the nine known G-protein-coupled sphingosine-1-phosphate (S1P) receptors act as a prime effector of neovascularization that occurs in embryonic development and in association with various pathologies. This review focuses on the current knowledge of the roles of S1P signaling in vasculogenesis and angiogenesis, with particular emphasis on vascular cell adhesion and motility responses.     

Sphingosine-1-phosphate stimulates rat primary chondrocyte proliferation

Rat primary chondrocytes express the sphingosine-1-phosphate (S1P) receptor, S1P(2), S1P(3), S1P(4), but not S1P(1). When chondrocytes were stimulated with S1P or phytosphingosine-1-phosphate (PhS1P, an S1P(1)- and S1P(4)-selective agonist), phospholipase C-mediated cytosolic calcium increase was dramatically induced. S1P and PhS1P also stimulated two kinds of mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK) and p38 kinase in chondrocytes. In terms of the two phospholipids-mediated functional modulation of chondrocytes, S1P and PhS1P stimulated cellular proliferation. The two phospholipids-induced chondrocyte proliferations were almost completely blocked by PD98059 but not by SB203580, suggesting that ERK but not p38 kinase is essentially required for the proliferation. Pertussis toxin almost completely inhibited the two phospholipids-induced cellular proliferation and ERK activation, indicating the crucial role of G(i) protein. This study demonstrates the physiological role of two important phospholipids (S1P and PhS1P) on the modulation of rat primary chondrocyte proliferation, and the crucial role played by ERK in the process.     

Sphingosine-1-phosphate Phosphatase 1 Regulates Keratinocyte Differentiation and Epidermal Homeostasis

Sphingosine 1-phosphate (S1P) is a bioactive lipid whose levels are tightly regulated by its synthesis and degradation. Intracellularly, S1P is dephosphorylated by the actions of two S1P-specific phosphatases, sphingosine-1-phosphate phosphatases 1 and 2. To identify the physiological functions of S1P phosphatase 1, we have studied mice with its gene, Sgpp1, deleted. Sgpp1^−/− mice appeared normal at birth, but during the 1st week of life they exhibited stunted growth and suffered desquamation, with most dying before weaning. Both Sgpp1^−/− pups and surviving adults exhibited multiple epidermal abnormalities. Interestingly, the epidermal permeability barrier developed normally during embryogenesis in Sgpp1^−/− mice. Keratinocytes isolated from the skin of Sgpp1^−/− pups had increased intracellular S1P levels and displayed a gene expression profile that indicated overexpression of genes associated with keratinocyte differentiation. The results reveal S1P metabolism as a regulator of keratinocyte differentiation and epidermal homeostasis.     

Sphingosine-1-phosphate as a mediator involved in development of fibrotic diseases

Fibrosis is a pathological process characterized by massive deposition of extracellular matrix (ECM) such as type I/III collagens and fibronectin that are secreted by an expanded pool of myofibroblasts, which are phenotypically altered fibroblasts with more contractile, proliferative, migratory and secretory activities. Fibrosis occurs in various organs including the lung, heart, liver and kidney, resulting in loss of normal tissue architecture and functions. Myofibroblasts could originate from multiple sources including tissue-resident fibroblasts, epithelial and endothelial cells through mechanisms of epithelial/endothelial-mesenchymal transition (EMT/EndMT), and bone marrow-derived circulating progenitors called fibrocytes. Emerging evidence in recent years shows that sphingosine-1-phosphate (S1P) acts on several types of target cells and is engaged in pro-fibrotic inflammatory process and fibrogenic process through multiple mechanisms, which include vascular permeability change, leukocyte infiltration, and migration, proliferation and myofibroblast differentiation of fibroblasts. Many of these S1P actions are receptor subtype-specific. In these actions, S1P has multiple cross-talks with other cytokines, particularly transforming growth factor-β (TGFβ), which plays a major role in fibrosis. The cross-talks include the regulation of S1P production through altered expression and activity of sphingosine kinases in fibrotic lesions, altered expression of S1P receptors, and S1P receptor-mediated transactivation of TGFβ signaling pathway. These cross-talks may give rise to a feed-forward, amplifying loop between S1P and TGFβ, and possibly with other cytokines in stimulating fibrogenesis. Another lysophospholipid mediator lysophosphatidic acid has also been recently implicated in fibrosis. The lysophospholipid signaling pathways represent novel, promising therapeutic targets for treating refractory fibrotic diseases. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.     

Sphingosine-1-phosphate modulates growth and adhesion of ovarian cancer cells

Sphingosine-1-phosphate (S1P) is a bioactive lipid molecule. It stimulates the growth of some cells, but inhibits the growth of others. In this study, we describe the detection of sub-microM to microM concentrations of S1P in the ascitic fluids of patients with ovarian cancer. In ovarian cancer cells cultured in vitro, S1P exhibited a dual effect on growth and/or survival. S1P (10 microM) induced cell death when cells were in suspension but stimulated cell growth when cells were attached. The calcium-dependent induction of cell death by S1P is apparently associated with its inhibitory effect on cell attachment and cell adhesion. S1P (10-30 microM) also induced calcium-dependent cell-cell aggregation.     

Sphingosine-1-phosphate lyase SPL is an endoplasmic reticulum-resident, integral membrane protein with the pyridoxal 5'-phosphate binding domain exposed to the cytosol

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that functions as a bioactive lipid molecule. S1P is degraded either by S1P lyase or by S1P phosphohydrolase. The gene encoding mammalian S1P lyase, SPL, has been identified. Here, we characterize the SPL protein in its expression, localization, and topology. The expression levels of the SPL protein correlated well with the dihydrosphingosine-1-phosphate (DHS1P) lyase activity in most tissues. However, liver and heart exhibited high DHS1P lyase activities compared to their SPL protein levels. The SPL mRNA expression was temporally regulated during mouse embryonal development. Immunofluorescence microscopy demonstrated that SPL is localized at the endoplasmic reticulum. Proteinase K digestion studies revealed that the large hydrophilic domain, containing the active site, faces the cytosol. This active site orientation is opposite to that of S1P phosphohydrolase, indicating that the degradation of S1P by two S1P-degrading enzymes occurs in spatially separated sides of the endoplasmic reticulum.     

An update on sphingosine-1-phosphate receptor 1 modulators

Sphingolipids represent an essential class of lipids found in all eukaryotes, and strongly influence cellular signal transduction. Autoimmune diseases like asthma and multiple sclerosis (MS) are mediated by the sphingosine-1-phosphate receptor 1 (S1P₁) to express a variety of symptoms and disease patterns. Inspired by its natural substrate, an array of artificial sphingolipid derivatives has been developed to target this specific G protein-coupled receptor (GPCR) in an attempt to suppress autoimmune disorders. FTY720, also known as fingolimod, is the first oral disease-modifying therapy for MS on the market. In pursuit of improved stability, bioavailability, and efficiency, structural analogues of this initial prodrug have emerged over time. This review covers a brief introduction to the sphingolipid metabolism, the mechanism of action on S1P₁, and an updated overview of synthetic sphingosine S1P₁ agonists.     

Cellular Localization of Sphingosine-1-phosphate Receptor 1 Expression in the Human Central Nervous System

Sphingosine-1-phosphate (S1P), a potent lipid mediator, transduces intracellular signals through the activation of S1P receptors (S1PRs). Although S1PRs have been shown to play an important role in the central nervous system (CNS), accurate localization and the function of S1PR1 in the human CNS are still unclear. In this study, we investigated the localization of S1PR1 in the human CNS of postmortem samples, using a rabbit polyclonal antibody, the specificity of which had been well defined. Immunohistochemical investigation of paraffin-embedded sections revealed diffuse granular staining of the gray matter. The signals of the gray matter were much stronger than those of the white matter. The immunohistochemical expression levels correlated well with the results of quantitative real-time RT-PCR–based analysis and Western blotting. Studies using double immunostaining and immunoelectron microscopy revealed that the antigen was strongly expressed in the membrane of the astrocytic foot processes of glia limitans and astrocytes with radial cytoplasm, but not distributed in neurons. In neurological disorders, hypertrophic astrocytes with strong expression of glial fibrillary acidic protein exhibited significantly decreased expression of S1PR1 in contrast to its strong expression in astrocytes forming fibrillary gliosis. These results indicate that S1PR1 is localized in astrocytes, and its expression level may change during the processes that occur after brain damage. (J Histochem Cytochem 58:847–856, 2010)