Metabolomics reveals metabolite changes of patients with pulmonary arterial hypertension in China

The specific mechanism of pulmonary arterial hypertension (PAH) remains elusive. The present study aimed to explore the underlying mechanism of PAH through the identity of novel biomarkers for PAH using metabolomics approach. Serum samples from 40 patients with idiopathic PAH (IPAH), 20 patients with congenital heart disease‐associated PAH (CHD‐PAH) and 20 healthy controls were collected and analysed by ultra‐high‐performance liquid chromatography coupled with high‐resolution mass spectrometry (UPLC‐HRMS). Orthogonal partial least square‐discriminate analysis (OPLS‐DA) was applied to screen potential biomarkers. These results were validated in monocrotaline (MCT)‐induced PAH rat model. The OPLS‐DA model was successful in screening distinct metabolite signatures which distinguished IPAH and CHD‐PAH patients from healthy controls, respectively (26 and 15 metabolites). Unbiased analysis from OPLS‐DA identified 31 metabolites from PAH patients which were differentially regulated compared to the healthy controls. Our analysis showed dysregulation of the different metabolic pathways, including lipid metabolism, glucose metabolism, amino acid metabolism and phospholipid metabolism pathways in PAH patients compared to their healthy counterpart. Among these metabolites from dysregulated metabolic pathways, a panel of metabolites from lipid metabolism and fatty acid oxidation (lysophosphatidylcholine, phosphatidylcholine, perillic acid, palmitoleic acid, N‐acetylcholine‐d ‐sphingomyelin, oleic acid, palmitic acid and 2‐Octenoylcarnitine metabolites) were found to have a close association with PAH. The results from the analysis of both real‐time quantitative PCR and Western blot showed that expression of LDHA, CD36, FASN, PDK1 GLUT1 and CPT‐1 in right heart/lung were significantly up‐regulated in MCT group than the control group.     

基于脂质组学技术研究急性缺血性脑卒中临床诊断标志物

目的:急性缺血性脑卒中(Acute ischemic stroke, AIS)是由于血流减少导致的脑功能突然丧失。由于AIS发病机制是异质性和多因素的,我们建立全面的脂质组学方法来阐明AIS进程相关的脂质变化和复杂的脂质代谢网络。方法:选取26例AIS患者血液标本和27例健康志愿者血清作为研究对象,进行总脂抽提,通过基于LC-MS策略的非靶向脂质组学方法进行规模性、整体性的脂质组学分析。结果:对AIS患者和健康志愿者血浆进行大规模脂质定性定量分析,通过Progenesis~? QI软件分析Xevo~? G2-XS QTOF质谱系统MSE采集的子离子数据,精确定量到1054个脂质特征差异,准确定性得到368个脂质分子,多变量统计分析中差异脂质组成能将AIS患者和健康志愿者区分开来,通路富集分析图显示差异脂质主要参与甘油磷脂代谢的紊乱。结论:AIS患者血浆脂质组成与健康志愿者存在显著差异,差异表达的脂质可能与AIS发生有关。这些发现有助于开发新的诊断标志物和AIS治疗靶点。     

Gene expression changes induced by valproate in the process of rat hippocampal neural stem cells differentiation

Valproate (VPA), an effective clinical approved anti‐epileptic drug and mood stabilizer, has been believed to induce neuronal differentiation at the expense of inhibiting astrocytic and oligodendrocytic differentiation. Nevertheless, the involving mechanisms of it remain unclear yet. In the present study, we explored the global gene expression changes of fetus rat hippocampal neural stem cells following VPA treatment by high‐throughput microarray. We obtained 874 significantly upregulated genes and 258 obviously downregulated genes (fold change > 2 and P < 0.05). Then, we performed gene ontology and pathway analyses of these differentially expressed genes and chose several genes associated with nervous system according to gene ontology analysis to conduct expression analysis to validate the reliability of the array results as well as reveal possible mechanisms of VPA. To get a better comprehension of the differentially regulated genes by VPA, we conducted protein–protein association analysis of these genes, which offered a source for further studies. In addition, we made the overlap between the VPA‐downregulated genes and the predicted target genes of VPA‐upregulated microRNAs (miRNAs), which were previously demonstrated. These overlapped genes may provide a source to find functional VPA/miRNA/mRNA axes during neuronal differentiation. This study first constructed a comprehensive potential downstream gene map of VPA in the process of neuronal differentiation.     

Top-down lipidomics of low density lipoprotein reveal altered lipid profiles in advanced chronic kidney disease

This study compared the molecular lipidomic profile of LDL in patients with nondiabetic advanced renal disease and no evidence of CVD to that of age-matched controls, with the hypothesis that it would reveal proatherogenic lipid alterations. LDL was isolated from 10 normocholesterolemic patients with stage 4/5 renal disease and 10 controls, and lipids were analyzed by accurate mass LC/MS. Top-down lipidomics analysis and manual examination of the data identified 352 lipid species, and automated comparative analysis demonstrated alterations in lipid profile in disease. The total lipid and cholesterol content was unchanged, but levels of triacylglycerides and N-acyltaurines were significantly increased, while phosphatidylcholines, plasmenyl ethanolamines, sulfatides, ceramides, and cholesterol sulfate were significantly decreased in chronic kidney disease (CKD) patients. Chemometric analysis of individual lipid species showed very good discrimination of control and disease sample despite the small cohorts and identified individual unsaturated phospholipids and triglycerides mainly responsible for the discrimination. These findings illustrate the point that although the clinical biochemistry parameters may not appear abnormal, there may be important underlying lipidomic changes that contribute to disease pathology. The lipidomic profile of CKD LDL offers potential for new biomarkers and novel insights into lipid metabolism and cardiovascular risk in this disease.     

Systems level analysis of lipidome

Lipids, once thought to be mainly for energy-storage and structural purpose, have now gained immense recognition as a class of critical metabolites with versatile functions. The diversity and complexity of the cellular lipids are the main challenge for the comprehensive analysis of a lipidome. Lipidomics, which aims at mapping all of the lipids in a cell, is expanded rapidly in recent years, mainly attributed to recent advances in mass spectrometry (MS). MS-based lipidomic approaches developed recently allow the quick profiling of hundreds of lipids in a crude lipid extract. With the aid of latest computational tools/software (chemometrics), aberrant lipid metabolites or important signaling lipid(s) could be easily identified using unbiased lipid profiling approaches. Further tandem MS (MS/MS)-based lipidomic approaches, known as targeted approaches and able to convey structural information, hold the promise for high-throughput lipidome analysis. In this review, I discussed the basic strategy for systems level analysis of lipidome in biomedical study.     

Molecular interactions between wheat and cereal aphid (Sitobion avenae): analysis of changes to the wheat proteome

Aphids are major insect pests of cereal crops, acting as virus vectors as well as causing direct damage. The responses of wheat to infestation by cereal aphid (Sitobion avenae) were investigated in a proteomic analysis. Approximately, 500 protein spots were reproducibly detected in the extracts from leaves of wheat seedlings after extraction and 2‐DE. Sixty‐seven spots differed significantly between control and infested plants following 24 h of aphid feeding, with 27 and 11 up‐regulated, and 8 and 21 down‐regulated, in local or systemic tissues, respectively. After 8 days, 80 protein spots differed significantly between control and aphid treatments with 13 and 18 up‐regulated and 27 and 22 down‐regulated in local or systemic tissues, respectively. As positive controls, plants were treated with salicylic acid or methyl jasmonate; 81 and 37 differentially expressed protein spots, respectively, were identified for these treatments. Approximately, 50% of differentially expressed protein spots were identified by PMF, revealing that the majority of proteins altered by aphid infestation were involved in metabolic processes and photosynthesis. Other proteins identified were involved in signal transduction, stress and defence, antioxidant activity, regulatory processes, and hormone responses. Responses to aphid attack at the proteome level were broadly similar to basal non‐specific defence and stress responses in wheat, with evidence of down‐regulation of insect‐specific defence mechanisms, in agreement with the observed lack of aphid resistance in commercial wheat lines.     

Validation of a multiplexed and targeted lipidomics assay for accurate quantification of lipidomes

A major challenge of lipidomics is to determine and quantify the precise content of complex lipidomes to the exact lipid molecular species. Often, multiple methods are needed to achieve sufficient lipidomic coverage to make these determinations. Multiplexed targeted assays offer a practical alternative to enable quantitative lipidomics amenable to quality control standards within a scalable platform. Herein, we developed a multiplexed normal phase liquid chromatography-hydrophilic interaction chromatography multiple reaction monitoring method that quantifies lipid molecular species across over 20 lipid classes spanning wide polarities in a single 20-min run. Analytical challenges such as in-source fragmentation, isomer separations, and concentration dynamics were addressed to ensure confidence in selectivity, quantification, and reproducibility. Utilizing multiple MS/MS product ions per lipid species not only improved the confidence of lipid identification but also enabled the determination of relative abundances of positional isomers in samples. Lipid class-based calibration curves were applied to interpolate lipid concentrations and guide sample dilution. Analytical validation was performed following FDA Bioanalytical Method Validation Guidance for Industry. We report repeatable and robust quantitation of 900 lipid species measured in NIST-SRM-1950 plasma, with over 700 lipids achieving inter-assay variability below 25%. To demonstrate proof of concept for biomarker discovery, we analyzed plasma from mice treated with a glucosylceramide synthase inhibitor, benzoxazole 1. We observed expected reductions in glucosylceramide levels in treated animals but, more notably, identified novel lipid biomarker candidates from the plasma lipidome. These data highlight the utility of this qualified lipidomic platform for enabling biological discovery.     

Lipidomic alteration of plasma in cured COVID-19 patients using ultra high-performance liquid chromatography with high-resolution mass spectrometry

Background: The pandemic of novel coronavirus disease 2019 (COVID-19) has become a serious public health crisis worldwide. The symptoms of COVID-19 vary from mild to severe among different age groups, but the physiological changes related to COVID-19 are barely understood.Methods: In the present study, a high-resolution mass spectrometry (HRMS)-based lipidomic strategy was used to characterize the endogenous plasma lipids for cured COVID-19 patients with different ages and symptoms. These patients were further divided into two groups: those with severe symptoms or who were elderly and relatively young patients with mild symptoms. In addition, automated lipidomic identification and alignment was conducted by LipidSearch software. Multivariate and univariate analyses were used for differential comparison.Results: Nearly 500 lipid compounds were identified in each cured COVID-19 group through LipidSearch software. At the level of lipid subclasses, patients with severe symptoms or elderly patients displayed dramatic changes in plasma lipidomic alterations, such as increased triglycerides and decreased cholesteryl esters (ChE). Some of these differential lipids might also have essential biological functions. Furthermore, the differential analysis of plasma lipids among groups was performed to provide potential prognostic indicators, and the change in signaling pathways.Conclusions: Dyslipidemia was observed in cured COVID-19 patients due to the viral infection and medical treatment, and the discharged patients should continue to undergo consolidation therapy. This work provides valuable knowledge about plasma lipid markers and potential therapeutic targets of COVID-19 and essential resources for further research on the pathogenesis of COVID-19.     

Lipidomic profiling of model organisms and the world's major pathogens

Lipidomics is a subspecialty of metabolomics that focuses on water insoluble metabolites that form membrane barriers. Most lipidomic databases catalog lipids from common model organisms, like humans or Escherichia coli. However, model organisms' lipid profiles show surprisingly little overlap with those of specialized pathogens, creating the need for organism-specific lipidomic databases. Here we review rapid progress in lipidomic platform development with regard to chromatography, detection and bioinformatics. We emphasize new methods of comparative lipidomics, which use aligned datasets to identify lipids changed after introducing a biological variable. These new methods provide an unprecedented ability to broadly and quantitatively describe lipidic change during biological processes and identify changed lipids with low error rates.     

Heterogeneity of lipidomic profiles among lung cancer subtypes of patients

Lung cancer is a leading cause of cancer‐related deaths with an increasing incidence and poor prognoses. To further understand the regulatory mechanisms of lipidomic profiles in lung cancer subtypes, we measure the profiles of plasma lipidome between health and patients with lung cancer or among patients with squamous cell carcinomas, adenocarcinoma or small cell lung cancer and to correct lipidomic and genomic profiles of lipid‐associated enzymes and proteins by integrating the data of large‐scale genome screening. Our studies demonstrated that circulating levels of PS and lysoPS significantly increased, while lysoPE and PE decreased in patients with lung cancer. Our data indicate that lung cancer‐specific and subtype‐specific lipidomics in the circulation are important to understand mechanisms of systemic metabolisms and identify diagnostic biomarkers and therapeutic targets. The carbon atoms, dual bonds or isomerism in the lipid molecule may play important roles in lung cancer cell differentiations and development. This is the first try to integrate lipidomic data with lipid protein‐associated genomic expression among lung cancer subtypes as the part of clinical trans‐omics. We found that a large number of lipid protein‐associated genes significantly change among cancer subtypes, with correlations with altered species and spatial structures of lipid metabolites.     

Lipid signalling in plant responses to abiotic stress

Lipids are one of the major components of biological membranes including the plasma membrane, which is the interface between the cell and the environment. It has become clear that membrane lipids also serve as substrates for the generation of numerous signalling lipids such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, N‐acylethanolamines, free fatty acids and others. The enzymatic production and metabolism of these signalling molecules are tightly regulated and can rapidly be activated upon abiotic stress signals. Abiotic stress like water deficit and temperature stress triggers lipid‐dependent signalling cascades, which control the expression of gene clusters and activate plant adaptation processes. Signalling lipids are able to recruit protein targets transiently to the membrane and thus affect conformation and activity of intracellular proteins and metabolites. In plants, knowledge is still scarce of lipid signalling targets and their physiological consequences. This review focuses on the generation of signalling lipids and their involvement in response to abiotic stress. We describe lipid‐binding proteins in the context of changing environmental conditions and compare different approaches to determine lipid–protein interactions, crucial for deciphering the signalling cascades.     

Revealing serum lipidomic characteristics and potential lipid biomarkers in patients with POEMS syndrome

POEMS syndrome is a rare plasma cell dyscrasia with distinct lipid metabolism abnormalities at disease onset. However, the serum lipidomic characteristics in patients with POEMS syndrome were not investigated. The study performed an untargeted lipidome screening by liquid chromatography-tandem mass spectrometry (LS-MS/MS) in the pre- and post-treatment serum of 24 patients with POEMS syndrome, together with the serum of 24 paired healthy controls. Patients with POEMS syndrome had a distinct serum lipid composition compared with healthy controls, and a 3-lipid model had a predictive accuracy of 93.5% in distinguishing patients and healthy controls consisting of fatty acyl 17-oxo-20Z-hexacosenoic acid, phosphatidylcholine(16:0/18:1(9Z)) and sterol lipid 5b-pregnanediol. Four lipids including 17-oxo-20Z-hexacosenoic acid (r = 0.423, P = .040) were correlated with risk stratification, and 2 lipids including Cer(d18:0/13:0) were inversely related to serum vascular endothelial growth factor level (r=−0.465, P = .022). Eleven lipids were related to disease activity, including arachidonic acid which was inversely related and lysoPC(20:4) which was positively related. The study indicated a distinct lipid characteristic profile of patients with POEMS syndrome different from healthy controls and identified several lipids that may serve as potential diagnostic markers and monitors of therapeutic efficacy, as well as indicating potential metabolism pathways involved in the pathological process.     

Proteomic analysis of proteins differentially expressed in uterine lymphocytes obtained from wild‐type and NOD mice

Non‐obese diabetic (NOD) mice exhibit impaired fertility and decreased litter size when compared to wild type (WT) mice. However, it is unclear why allogeneic pregnant NOD mice are prone to spontaneous embryo loss. Herein, two‐dimensional gel electrophoresis (2‐DE) and mass spectrometry (MS) were used to detect differentially expressed proteins in the uterine lymphocytes isolated from these mice and WT BALB/c controls. We found 24 differentially expressed proteins. The differential expression of 10 of these proteins was further confirmed by Western blot analysis. Out of the 24 identified proteins, 20 were expressed in uterine lymphocytes of WT mice at a level at least 2 times higher than in NOD mice, whereas 4 were down‐regulated. Western blot analysis confirmed that 8 proteins were up‐regulated and 2 proteins were down‐regulated in WT mice compared with NOD mice, consistent with the results of 2‐DE and MS. Additionally, most of the highly expressed proteins in WT uterine lymphocytes were expressed at a significantly lower level in the corresponding splenic group (17/20). These results suggest that up‐regulated expression of these proteins may be specific to uterine lymphocytes. Reported functions of the highly expressed proteins affect key functions during pregnancy, including cell movement, cell cycle control, and metabolisms. Finally, we analyzed the constitutional ratio of CD3⁺ and CD49b⁺ cells in the isolated lymphocytes by flow cytometry. Our results suggest that the differentially expressed proteins may participate in the modulation of embryo implantation and early‐stage development of embryos, and subsequently influence pregnancy outcome. J. Cell. Biochem. 108: 447–457, 2009. © 2009 Wiley‐Liss, Inc.     

Lipidomic changes during different growth stages of Nitzschia closterium f. minutissima

Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF–MS) is a powerful lipidomic tool. In this study, we developed a UPLC/Q-TOF–MS based method to investigate the lipid metabolomic changes in different growth phases of Nitzschia closterium f. minutissima. The data classification and biomarker selection were carried out by using multivariate statistical analysis, including principal components analysis (PCA), projection to latent structures with discriminant analysis (PLS-DA), and orthogonal projection to latent structures with discriminant analysis (OPLS-DA). We discovered that the intercellular lipid metabolites were significantly different among exponential, early stationary and late stationary phases. Thirty-one lipid molecules were selected and identified as putative biomarkers, including free fatty acid, Harderoporphyrin, phosphatidylglycerol, 1,2-diacyglycerl-3-O-4′-(N,N-trimethy)-homoserine, triacylglycerol, cholesterol, sulfoquinovosyldiacylglycerol, lyso-sulfoquinovosyldiacylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and lyso-digalactosyldiacylglycerol. These lipids have been shown previously to function in energy storage, membrane stability and photosynthesis efficiency during the growth of diatoms. Further analysis on the putative biomarkers demonstrated that nitrate starvation played critical role in the transition from exponential phase to stationary phase in N. closterium. This study is the first one to explore the lipidomic changes of microalgae in different growth phases, which promotes better understanding of their physiology and ecology.     

柞蚕微粒子病潜在生物标志物的挖掘

【目的】挖掘柞蚕Antheraea pernyi微粒子病的潜在生物标志物,为开发该病害检测方法及研究柞蚕被微孢子虫Nosema pernyi侵染后体内代谢产物的差异及功能奠定基础。【方法】利用高效液相色谱和高分辨率质谱进行非靶向代谢组学分析,调查健康和患微粒子病柞蚕雌成虫血淋巴中代谢物差异。【结果】正离子模式下从健康和患微粒子病柞蚕雌成虫血淋巴中共获得8 870个代谢物,注释代谢物5 390个,筛选到差异表达代谢物472个(上调260个,下调212个),其中二级鉴定差异表达代谢物12个(上调8个,下调4个);负离子模式下获得6 716个代谢物,注释代谢物3 848个,筛选到差异表达代谢物301个(上调207个,下调94个),其中二级鉴定差异表达代谢物9个(上调8个,下调1个)。正离子模式下二级鉴定的差异表达代谢物包括缬氨酸(valine)、苯并噻唑(benzothiazole)、3-脱羟基肉碱(3-dehydroxycarnitine)、1 甲基鸟嘌呤(1-methylguanine)、2-乙氧基萘(2-ethoxynaphthalene)、N6-乙酰基-L-赖氨酸(N6-acetyl-L-lysine)、生物素(biotin)、桑色素(morin)、噻吗洛尔(timolol)、酰基肉碱15∶0(acylcarnitine 15∶0)、酰基肉碱18∶4(acylcarnitine 18∶4)和异槲皮苷(isoquercitrin);负离子模式下二级鉴定的差异表达代谢物包括二甲基丙二酸(dimethylmalonic acid)、戊二酸(glutaric acid)、2,5-二羟基苯甲酸(2,5-dihydroxybenzoic acid)、1,3-二乙酰基丙烷(1,3-diacetylpropane)、3-(4-羟基苯基)乳酸(DL-p-hydroxyphenyllactic acid)、泛酸(pantothenate)、荧光素(fluorescein)、飞燕草素-3-O-beta-吡喃葡萄糖苷(delphinidin-3-O-beta-glucopyranoside)和溶血磷酯酰肌醇16∶1 (lysoPI 16∶1)。【结论】健康与患柞蚕微粒子病的柞蚕雌成虫血淋巴内代谢物具有显著差异,通过代谢组学挖掘出21个二级鉴定的差异表达代谢物,这些代谢物可作为潜在生物标志物用于开发柞蚕微粒子病的检测方法。     

Plasma GABA levels in neurological patients under treatment with valproic acid

The effect of chronic treatment with valproic acid (VPA), administered as its sodium salt, on the plasma concentrations of GABA was studied in 5 in-patients. Within 2–10 days of treatment with daily doses of 1500–3000 mg sodium VPA GABA levels increased to 30–80 % compared to control days. This increase was transient in 3 out of 5 patients. In 19 epileptic patients under VPA medication plasma GABA levels were 40 % higher than those determined in non-epileptic patients serving as controls. The possibility that the increase in plasma GABA induced by VPA reflects similar increases in brain GABA content is discussed.     

Potential biomarkers for the clinical prognosis of severe dengue

Currently, several assays can confirm acute dengue infection at the point-of-care. However, none of these assays can predict the severity of the disease symptoms. A prognosis test that predicts the likelihood of a dengue patient to develop a severe form of the disease could permit more efficient patient triage and treatment. We hypothesise that mRNA expression of apoptosis and innate immune response-related genes will be differentially regulated during the early stages of dengue and might predict the clinical outcome. Aiming to identify biomarkers for dengue prognosis, we extracted mRNA from the peripheral blood mononuclear cells of mild and severe dengue patients during the febrile stage of the disease to measure the expression levels of selected genes by quantitative polymerase chain reaction. The selected candidate biomarkers were previously identified by our group as differentially expressed in microarray studies. We verified that the mRNA coding for CFD, MAGED1, PSMB9, PRDX4 and FCGR3B were differentially expressed between patients who developed clinical symptoms associated with the mild type of dengue and patients who showed clinical symptoms associated with severe dengue. We suggest that this gene expression panel could putatively serve as biomarkers for the clinical prognosis of dengue haemorrhagic fever.     

Unbiased lipidomic profiling reveals metabolomic changes during the onset and antipsychotics treatment of schizophrenia disease

Introduction

Schizophrenia (SCH) is one of the most common psychiatric disorders, which involves impairments in motivation and cognition. The pathological mechanisms underlying SCH are still unknown, and no effective therapies can prevent or treat perfectly the cognitive impairments and deficit symptoms caused by SCH.

Objectives

We aimed to find the lipid expression change in plasma that underlie SCH onset and antipsychotics treatment.

Methods

We performed a data independent acquisition-based untargeted lipidomic approach on a quadrupole-time of flight liquid chromatography coupled to mass spectrometry platform. The plasma lipidomic profiles of SCH patients (n?=?20) pre- and post-antipsychotics treatment were acquired as well as healthy controls (n?=?29). Grouped or paired t-test were used to analyze the data.

Results

Over 1000 features were detected by our lipidomic analysis, of which 445 lipids belonging to 17 lipid species were reliably identified by tandem mass spectrometry. After statistical analysis, 47 lipids belonging to 9 lipid species were found to be dysregulated between naive SCH patients and healthy controls, and 50 lipids belonging to 9 lipid species were found to be dysregulated after antipsychotics treatment. These findings include several new SCH-relevant lipid species such as sphingomyelin, acylcarnitine and ceramide. Four types of lipid expression regulative patterns can be concluded from the above mentioned findings, revealing information about mechanism, side-effect and potential target of antipsychotics.

Conclusions

The work presented here have revealed several new lipid species which are significantly dysregulated in SCH disease development or antipsychotics treatment. These lipids provide new evidence for the pathological studies of SCH and new antipsychotics development, or can be considered as potentially candidate biomarkers for further validation.