Bile acids and sphingolipids in cholangiocarcinoma

Objective:Cholangiocarcinoma(CCA)is a rare but highly malignant hepatobiliary cancer with a very poor prognosis and limited treatment options.CCA is commonly associated with chronic cholestasis and significantly elevated levels of primary and conjugated bile acids(CBAs),which are correlated with bile duct obstruction.

Sphingolipids in cardiovascular and cerebrovascular systems:Pathological implications and potential therapeutic targets

The sphingolipid metabolites ceramide,sphingosine,and sphingosine-1-phosphate(S1P) and its enzyme sphingosine kinase(SphK) play an important role in the regulation of cell proliferation,survival,inflammation,and cell death.Ceramide and sphingosine usually inhibit proliferation and promote apoptosis,while its metabolite S1P phosphorylated by SphK stimulates growth and suppresses apoptosis.Because these metabolites are interconvertible,it has been proposed that it is not the absolute amounts of these metabolites but rather their relative levels that determine cell fate.The relevance of this "sphingolipid rheostat" and its role in regulating cell fate has been borne out by work in many labs using many different cell types and experimental manipulations.A central finding of these studies is that SphK is a critical regulator of the sphingolipid rheostat,as it not only produces the pro-growth,anti-apoptotic messenger S1P,but also decreases levels of pro-apoptotic ceramide and sphingosine.Activation of bioactive sphingolipid S1P signaling has emerged as a critical protective pathway in response to acute ischemic injury in both cardiac and cerebrovascular disease,and these observations have considerable relevance for future potential therapeutic targets.

Emerging roles and therapeutic potentials of sphingolipids in pathophysiology:emphasis on fatty acyl heterogeneity

Sphingolipids not only exert structural roles in cellular membranes,but also act as signaling molecules in various physiological and pathological processes.A myriad of studies have shown that abnormal levels of sphingolipids and their metabolic enzymes are associated with a variety of human diseases.Moreover,blood sphingolipids can also be used as biomarkers for disease diagnosis.This review summarizes the biosynthesis,metabolism,and pathological roles of sphingolipids,with emphasis on the biosynthesis of ceramide,the precursor for the biosynthesis of complex sphingolipids with different fatty acyl chains.The possibility of using sphingolipids for disease prediction,diagnosis,and treatment is also discussed.Targeting endogenous ceramides and complex sphingolipids along with their specific fatty acyl chain to promote future drug development will also be discussed.

Bile acids and sphingolipids in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the fastest-growing diseases, and its global prevalence is estimated to increase >50% by 2030. NAFLD is comorbid with metabolic syndrome, obesity, type 2 diabetes, and insulin resistance. Despite extensive research efforts, there are no pharmacologic or biological therapeutics for the treatment of NAFLD. Bile acids and sphingolipids are well-characterized signaling molecules. Over the last few decades, researchers have uncovered potential mechanisms by which bile acids and sphingolipids regulate hepatic lipid metabolism. Dysregulation of bile acid and sphingolipid metabolism has been linked to steatosis, inflammation, and fibrosis in patients with NAFLD. This clinical observation has been recapitulated in animal models, which are well-accepted by experts in the hepatology field. Recent transcriptomic and lipidomic studies also show that sphingolipids are important players in the pathogenesis of NAFLD. Moreover, the identification of bile acids as activators of sphingolipid-mediated signaling pathways established a novel theory for bile acid and sphingolipid biology. In this review, we summarize the recent advances in the understanding of bile acid and sphingolipid-mediated signaling pathways as potential contributors to NAFLD. A better understanding of the pathologic effects mediated by bile acids and sphingolipids will facilitate the development of new diagnostic and therapeutic strategies for NAFLD.

Sphingolipids Profiling of Plasma in Patients with Diabetes Mellitus Associated with Atherosclerosis by a Novel Normal-Phase UPLC-QToF MS Method

A novel normal-phase UPLC-QToF MS method was developed for sphingolipids analysis,which was then applied to separate and identify seven classes of sphingolipids in plasma.The time-consuming of this novel method was much shorter than previous 2D LC–MS method,while the sensitivity,repeatability and resolution for sphingolipids analysis were better or comparable.Besides,the differences of lipids in human plasma among diabetes mellitus patients,diabetes mellitus associated with atherosclerosis patients and control subjects were also compared.Finally,12 sphingolipids species were identified as the amounts of which in diabetes mellitus associated with atherosclerosis patients were significantly higher than them in diabetes mellitus patients(VIP>1.0,p value<0.05,fold change>1.5).As the isomers of GalCs and GluCs were successfully separated,it was found that five GluCs,rather than GalCs,were included in these 12 potential biomarkers.These results suggest the need to separate GalCs from GluCs,and also indicated that there may be some extra activation pathways of diabetes mellitus associated with atherosclerosis,different from the atherosclerosis pathway and the diabetes mellitus pathway,causing cardiovascular disease.

miR-139-5p对人肝癌细胞增殖和侵袭的影响

目的 探讨微小RNA(miRNA)-139-5p在肝癌组织中的表达及其对人肝癌细胞增殖、侵袭的影响和潜在的分子机制。方法 采用生物信息学方法,从GEO数据库中下载GSE36915数据集,进行差异miRNA分析,结合TCGA-LICH数据集中的生存数据,筛选与预后显著相关的miRNA。采用实时荧光定量PCR(qRT-PCR)检测miR-139-5p在肝癌及其癌旁组织中的表达。利用CCK-8实验、Transwell实验观察miR-139-5p对人肝癌细胞SK-Hep-1和SMMC-7721的表型变化。采用高通量测序检测过表达miR-139-5p的SK-Hep-1细胞中基因表达的变化,确定miR-139-5p调控的潜在的信号通路和靶基因,并采用免疫印迹实验和报告基因实验进行验证。结果 通过对GSE36915数据集进行分析,共鉴定到50个显著差异表达的miRNA。结合TCGA-LICH数据集中的生存数据,发现在差异最显著的20个miRNA中,miR-15b-3p、miR-1180-3p、miR-139-5p、miR-139-3p与预后显著相关,最终确定miR-139-5p为进一步研究对象。miR-139-5p在100对肝癌组织的相对表达水平显著低于对应癌旁组织[(0.50±0.33) vs (1.02±0.43),P<0.001],且低水平的miR-139-5p肝癌患者中位生存期较短(25.5个月vs 43.0个月,P<0.01)。人肝癌细胞系SK-Hep-1和SMMC-7721中过表达miR-139-5p,可以显著抑制肝癌细胞的增殖和侵袭。高通量测序分析发现,在过表达miR-139-5p的SK-Hep-1细胞中,差异表达基因显著富集在Sphingolipid信号通路。经免疫印迹实验和报告基因实验验证,Sphingolipid信号通路中神经酰胺合成酶6(ceramide synthase 6,CerS6)是miR-139-5p的新的靶点。结论 miR-139-5p在肝癌组织中表达减少,导致其下游靶基因CerS6过量表达,从而激活Sphingolipid信号通路,促进肝癌发生发展。本研究提示miR-139-5p可以作为肝癌治疗的新的靶点。

Characterization of the sphingolipid profiling of Emiliania huxleyi against virus infection

Lipidomics approach by UPLC-Q-Exactive-MS was used for the identification,quantification,comparison,and characterization of sphingolipids in virus infected marine Emiliania huxleyi BOF92 cells.The results show that 16 significantly changed sphingolipids(including Cer,CerG1,and SPHm)were identified during viral infection.Our data confirmed previously recognized facts that viral infection led to a shift toward virus-specific sphingolipids,which is consistent with the down-regulation of genes involved in the host de novo sphingolipid biosynthesis.Moreover,we revealed the upregulation of virusencoded homologous genes participating in de novo sphingolipids biosynthesis and virus-specific hydroxylated long chain bases(LCBs)as phytoCer,suggesting the competitive inhibition of host sphingolipid synthesis to produce the required building blocks for viral production,replication,and assembly.Additionally,Cer 40꞉1;2,Cer 40꞉2;2 isomer,and CerG139꞉0;2,Cer 39꞉0;2 as novel metabolite markers might indicate the general dysfunctions in E.huxleyi in response to viral infection.Our results show that viral infection led to a profound remodeling of host sphingolipidome,by which viruses depend on the hijacking of host sphingolipid metabolism to support the viral life cycle.

Role of glioma immune biomarker ORMDL2 in the diagnosis and prognosis of glioma

Obiective:To investigate the prognostic value of ORMDL2 in human glioma and its relationship with immune invasion.Methods:The clinical survival data from TCGA-LGG&GBM,CGGA and GEO were used to evaluate the clinical prognostic value of ORMDL2.The cut off value of ORMDL2 was detected with pROC package to draw ROC curve to prove its value in differential diagnosis of glioma.The first 300 genes with the most significant positive correlation with ORMDL2 were selected to establish PPI network through STRING database and conduct GO and pathway analysis.The relationship between the expression of ORMDL2 mRNA and immune cell infiltration was investigated by using ssGSEA and TIMER2.0 databases.Results:The expression of ORMDL2 mRNA in glioma was significantly higher than that in adjacent normal tissues,and the difference was most significant in high-grade glioma.The expression of ORMDL2 was increased in human glioma,which was related to the clinicopathological characteristics and poor prognosis of glioma patients.In addition,the increased expression of ORMDL2 was associated with a series of immune infiltrating cells,including macrophages.Conclusion:ORMDL2 plays an important role in glioma immune cell infiltration and is a biomarker of prognosis of glioma patients.

Research progress of sphingosine 1-phosphate and its signal transduction in central nervous system diseases

Sphingosine 1-phosphate(S1P),as a sphingolipid metabolite,has become a key substance in regulating various physiological processes,involved in differentiation,proliferation,migration,morphogenesis,cytoskeleton formation,adhesion,apoptosis,etc.process.Sphingosine 1-phosphate can not only activate the S1P-S1PR signaling pathway by binding to the corresponding receptors on the cell membrane,but also play a role in the cell.In recent years,studies have found that there is a certain relationship between its level changes and the occurrence and development of central nervous system diseases.This article reviews the latest knowledge of sphingosine-1-phosphate in the occurrence and treatment of nervous system diseases,and further clarifies its molecular mechanism in the treatment and development of central nervous system diseases.

New insights into renal lipid dysmetabolism in diabetic kidney disease

Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs,including the kidney.Research suggests that impaired cholesterol metabolism,increased lipid uptake or synthesis,increased fatty acid oxidation,lipid droplet accumulation and an imbalance in biologically active sphingolipids(such as ceramide,ceramide-1-phosphate and sphingosine-1-phosphate)contribute to the development of diabetic kidney disease(DKD).Currently,the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production,oxidative stress,inflammation,or cell death.Therefore,control of renal lipid dysmetabolism is a very important therapeutic goal,which needs to be archived.This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.

Regulation of cancer cell migration and invasion by sphingosine-1-phosphate

Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid that has been implicated in regulation of a number of cancer cell malignant behaviors, including cell proliferation, survival, chemotherapeutic resistance and angiogenesis. However, the effects of S1P on cancer cell migration, invasion and metastasis, are perhaps its most complex, due to the fact that, depending upon the S1P receptors that mediate its responses and the crosstalk with other signaling pathways, S1P can either positively or negatively regulate invasion. This review summarizes the effects of S1P on cancer cell invasion and the mechanisms by which it affects this important aspect of cancer cell behavior.

Obesity-associated steatotic liver exhibits aberrant or altered sphingolipid composition and preferentially accumulates ceramide species containing long chain fatty acids

The sphingolipid (SL) signaling pathways are induced by reactive oxygen species and proin-flammatory molecules, which are shown to be upregulated in the obese state. The present work was conducted to determine if an altered SL pathway exists, and contributes to the pathogenesis of hepatic steatosis associated with obesity. Steatotic and non-steatotic livers were procured from Zucker Obese female rats and their lean counterparts in this pre-clinical study, and assessed for enzymes involved in degradation as well as in phos-phorylation of proapoptotic SLs. The expression of enzymes [sphingo-myelinase (SMase), ceramidase, and sphingosine kinase-1 (SK1)] and apoptotic proteins (Bax and Bcl-2) was quantified by ELISA and by Western Blot. Sphingomyelin (SM), ceramide, ceramide-1 phosphate (C1P), sphingosine (SPH), and sphingosine-1-phosphate (S1P) levels were quantified by high-performance liquid chroma-tography (HPLC)-tandem mass spectroscopy (MS). Obese steatotic livers exhibited significantly upregulated ceramidase and down-regulated SK1 and C1P levels (P < 0.05), as well as significantly lower levels of SM and higher levels of ceramide species containing long chain fatty acids, compared to their lean counterparts. These findings demonstrate that obese liver harbours SLs that favour a proapoptotic environment. Moreover, accumulation of ceramides containing long chain fatty acids could be involved in the pathogenesis of hepatic steatosis.

Orosomucoid-like protein 3,rhinovirus and asthma

The genetic variants of orosomucoid-like protein 3(ORMDL3)gene are associated with highly significant increases in the number of human rhinovirus(HRV)-induced wheezing episodes in children.Recent investigations have been focused on the mechanisms of ORMDL3 in rhinovirus infection for asthma and asthma exacerbations.ORMDL3 not only regulates major human rhinovirus receptor intercellular adhesion molecule 1 expression,but also plays pivotal roles in viral infection through metabolisms of ceramide and sphingosine-1-phosphate,endoplasmic reticulum(ER)stress,ER-Golgi interface and glycolysis.Research on the roles of ORMDL3 in HRV infection will lead us to identify new biomarkers and novel therapeutic targets in childhood asthma and viral induced asthma exacerbations.

Regulatory role of sphingosine kinase and sphingosine-1-phosphate receptor signaling in progenitor/stem cells

Balanced sphingolipid signaling is important for the maintenance of homeostasis. Sphingolipids were demonstrated to function as structural components, second messengers, and regulators of cell growth and survival in normal and disease-affected tissues. Particularly, sphingosine kinase 1 (SphK1) and its product sphingosine-1-phosphate (S1P) operate as mediators and facilitators of proliferation-linked signaling. Unlimited proliferation (selfrenewal) within the regulated environment is a hallmark of progenitor/stem cells that was recently associated with the S1P signaling network in vasculature, nervous,muscular, and immune systems. S1P was shown to regulate progenitor-related characteristics in normal and cancerstemcells(CSCs) viaG-protein coupled receptorsS1Pn(n=1 to 5). The SphK/S1P axis is crucially involved in the regulation of embryonic development of vasculature and the nervous system, hematopoietic stem cell migration, regeneration of skeletal muscle, and development of multiple sclerosis. The ratio of the S1P receptor expression, localization, and specific S1P receptoractivated downstream effectors influenced the rate of selfrenewal and should be further explored as regeneration related targets. Considering malignant transformation,it is essential to control the level of self-renewal capacity.Proliferation of the progenitor cell should be synchronized with differentiation to provide healthy lifelong function of blood, immune systems, and replacement of damaged ordead cells. The differentiation-related role of SphK/S1P remains poorly assessed. A few pioneering investigations exploredpharmacologicaltoolsthattargetsphingolipid signaling and can potentially confine and direct self-renewal towards normal differentiation. Further investigation is required to test the role of the SphK/S1P axis in regulation of self-renewal and differentiation.

Advances on Current Techniques and Methodologies in Milk Lipidomics

Milk is a complex biological fluid containing lipids,proteins,carbohydrates and minerals,which are essential for infant growth.While the lipid portion constitutes only 3%-5%of the total milk composition,it accounts for over 50%of the infant’s daily energy intake.The dominant portion(approximately 98%)is in the form of triacylglycerols and polar lipids,such as glycerophospholipids and sphingolipids,forming minor components.Recently,with the development of lipidomics,important progresses have been made in milk lipidomics,and the identification and quantification of several milk lipids at the group and molecular species level has become a reality,thereby providing useful information for the infant formula industry.In this review,an overview of the separation of the main components of milk lipids was presented,including glycerolipids,phospholipids and sphingolipids.The analytical methods and strategies for milk lipidomics,including gas chromatography-mass spectrometry(MS),capillary electrophoresis MS,nuclear magnetic resonance,matrix-assisted laser desorption ionization-MS,electrospray ionization-MS,shotgun lipidomics and liquid chromatography-MS,were reviewed.Additionally,the bioinformatics of lipidomics for milk lipid determination,including lipid classification,lipid databases and lipid analysis software,were investigated.This review would aid future investigations of the nutrition of milk lipids and refined researches on formula milk powder.

Sphk1 Expression and Survival Outcomes in Squamous Cell Carcinoma of the Oral Cavity

Sphingosine kinase 1 (SphK1) is an important mediator of apoptosis and the proliferation of cancer cells. It is upregulated in cells showing increasing radioresistance. Here we present the correlation between SphK1 expression and survival outcomes in patients with carcinoma of the oral cavity. A retrospective chart review was performed between January 2009 and August 2010 at the University of Southern California. Patients diagnosed with an advanced-stage primary tumor restricted to the oral cavity and a minimum follow-up of two years were included. Patients who did not receive post-operative radiation therapy were excluded. Eighteen patients met the inclusion criteria with 10 (55.6%) patients demonstrating high expression of SphK1 and 8 (44.4%) patients demonstrating a low-to-moderate expression of SphK1. Tumor recurrence occurred in 9 patients (50.0%): 5 patients (27.8%) in the SphK1high cohort at a mean time to progression of 2.5 mo and 4 patients (22.2%) in the SphK1low cohort at a mean time to progression of 11.0 mo (p = 0.023). Death occurred in 8 patients (66.7%) in the SphK1high cohort and 3 patients (16.7%) in the SphK1low cohort (p = 0.036). Higher expression of SphK1 correlates with greater radioresistance and poorer survival outcomes in patients with HNSCC of the oral cavity.

Sphingosine 1-phosphate in inflammation

Sphingolipids are formed via the metabolism of sphingomyelin,aconstituent of the plasma membrane.or by denovosynthesis.Enzymatic pathways result in the formation of sevenal different lipid meiators,which are knowm to bave important roles in many elllar proceses.imcluding polfeatioe,apoptosis and migation Several studies nDowr suggest that these shingolipid mediators,inchding cenamide,ceramside i-pbosphate and sphingosine 1-pbosphate(SIP).are likely to have a integral role in infamation.This can involve,for example activation of po-inammatory transcription factors in different cell types and indiuction of cyloxygenase-2.leading t如o productio of pro-inamatory prostaglandins.The mode of action of each sphingolipid is different.Increased ceramide production leads to the formation of ceramide-rich areas of the membnane.which may assemble sigalling compleses,whereas SIP acts via b-affnity G-protein-coupled SIP receptors on the plasma membrane.Recent studies bave demonstated that in vitro efects of sphingolipids o infammation can translate into in vivo models.This review will higblight the areas of research where spbingolipids ae involved in infamomation and the mecharisms of acion of each mediator.In adirion,the therpeutic poternial of dinugs that alter sphingolipid actions mill be exmined with reference to disease states,such as asthma and infammatary bowel disease,which invove importanot ifmaxmsutory components.A signifcant body of research now indicates that sphingolipids ure intimately inolved in the infammatory process and recent studies have demonstated that these lipids.together with associated enzymes and receptors,can provide effective drug targets for the treatment of pathological inflammation.

Defect of insulin signal in peripheral tissues: important role of ceramide

In healthy people,balance between glucose production and its utilization is precisely controlled.When circulating glucose reaches a critical threshold level,pancreaticβcells secrete insulin that has two major actions:to lower circulating glucose levels by facilitating its uptake mainly into skeletal muscle while inhibiting its production by the liver.Interestingly,dietary triglycerides are the main source of fatty acids to fulfill energy needs of oxidative tissues.Normally,the unconsumed fraction of excess of fatty acids is stored in lipid droplets that are localized in adipocytes to provide energy during fasting periods.Thus,adipose tissue acts as a trap for fatty acid excess liberated from plasma triglycerides.When the buffering action of adipose tissue to store fatty acids is impaired,fatty acids that build up in othertissues are metabolized as sphingolipid derivatives such as ceramides.Several studies suggest that ceramides are among the most active lipid second messengers to inhibit the insulin signaling pathway and this review describes the major role played by ceramide accumulation in the development of insulin resistance of peripherals tissues through the targeting of specific proteins of the insulin signaling pathway.

Oral mucosal lipids are antibacterial against Porphyromonas gingivalis, induce ultrastructural damage, and alter bacterial lipid and protein compositions

Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria;however,little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria.In this study,we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis,an important colonizer of the oral cavity implicated in periodontitis.Minimal inhibitory concentrations,minimal bactericidal concentrations,and kill kinetics revealed variable,but potent,activity of oral mucosal and salivary lipids against P.gingivalis,indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria,although specific components of bacterial membranes are also likely important.Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane.This information,coupled with the association of treatment lipids with P.gingivalis lipids revealed via thin layer chromatography,suggests that the plasma membrane is a likely target of lipid antibacterial activity.Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P.gingivalis stress response,including proteins important in fatty acid biosynthesis,metabolism and energy production,protein processing,cell adhesion and virulence.Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces.

Crosslink between lipids and acute uveitis：a lipidomic analysis

AIM:To explore the roles of phospholipids and sphingolipids in the inflammatory process of uveitis.METHODS:Aqueous humor(AH) and the retina were obtained from endotoxin-induced uveitis(EIU) rats during the acute inflammation stage(24 h after endotoxin injection).Lipids were extracted using a modified Bligh and Dyer method and subjected to mass spectrometric identification using class-specific lipid standards and ratiometric quantification.Relative intensity analysis was performed to evaluate the amount change of common lipids between the EIU and control groups.RESULTS:Unique lipid species encompassing all five phospholipid classes were found in both control and the EIU AH and retina.Commensurate with the significantly increased level of lysophospholipids in the EIU AH and retina,we found that the ratio of lysophospholipids to total phospholipids was significantly increased too.We also detected a significant increase in 18:0 lysophosphatidylcholine levels in the EIU group(fold change =6.4 in AH and 3.8 in retina).Cer240,Cer241,and SM240 levels remarkably increased in the EIU AH.Enhanced C12 ceramide-1-phosphate(C12 C-1-P),C16 C-1-P,C24 C-1-P,and upregulated Cer160,Cer240,SM120,and SM240 were found in EIU retina.C-1-P was believed to restore homeostasis by inhibiting nuclear factor kappa B(NF-κB) activation.However,we still found elevated NF-κB levels in the EIU retina.CONCLUSION:A variety of lipids might have played a critical role in EIU inflammation.Exogenous topical application of these protective lipids or inhibition of these pro-inflammatory lipids may be useful therapeutic strategies for the resolution of EIU.