Lipids and lipidomics in brain injury and diseases

Lipidomics is systems-level analysis and characterization of lipids and their interacting moieties. The amount of information in the genomic and proteomic fields is greater than that in the lipidomics field, because of the complex nature of lipids and the limitations of tools for analysis. The main innovation during recent years that has spurred advances in lipid analysis has been the development of new mass spectroscopic techniques, particularly the "soft ionization" techniques electrospray ionization and matrix-assisted laser desorption/ionization. Lipid metabolism may be of particular importance for the central nervous system, as it has a high concentration of lipids. The crucial role of lipids in cell signaling and tissue physiology is demonstrated by the many neurological disorders, including bipolar disorders and schizophrenia, and neurodegenerative diseases such as Alzheimer's, Parkinson's, and Niemann-Pick diseases, that involve deregulated lipid metabolism. Altered lipid metabolism is also believed to contribute to cerebral ischemic (stroke) injury. Lipidomics will provide a molecular signature to a certain pathway or a disease condition. Lipidomic analyses (characterizing complex mixtures of lipids and identifying previously unknown changes in lipid metabolism) together with RNA silencing, using small interfering RNA (siRNA), may provide powerful tools to elucidate the specific roles of lipid intermediates in cell signaling and open new opportunities for drug development.     

基于高分辨率质谱的金欣口服液治疗小鼠RSV感染的血清脂质组学研究

目的 基于UHPLC-Q-Exactive Orbitrap MS高分辨率质谱,观察RSV诱发的肺炎模型小鼠的血清中脂质代谢的变化,分析金欣口服液对RSV肺炎小鼠中脂质代谢紊乱的调节作用,探讨金欣口服液治疗RSV诱发的病毒性肺炎的潜在机制。方法 用RSV诱导小鼠病毒性肺炎,灌胃金欣口服液予以治疗,分别采集对照组、模型组、金欣口服液组小鼠的血清样本,提取脂质成分,采用LC-MS分析,采用主成分分析法（PCA）、聚类分析法（CA）等多元统计方法,对小鼠血清脂质代谢轮廓进行分析,同时进行Kruskal–Wallis test以及fold change法进行统计,寻找差异性脂质。结果 RSV感染导致小鼠肺部炎性细胞浸润及不同程度的肺炎,血清中多种脂质代谢物代谢紊乱,具体表现多数PC、PE出现明显上调,金欣口服液均能改善小鼠肺炎症状且显著恢复血清中异常紊乱的脂质。结论 RSV感染可导致小鼠血清中脂质代谢紊乱,而金欣口服液可一定程度恢复RSV模型中代谢紊乱的脂质,提示金欣口服液可通过调节脂质改善RSV诱发的肺炎。      

代谢组学和脂质组学在哮喘研究中的应用进展

哮喘是常见的慢性炎症性疾病,以喘息、胸闷、咳嗽、呼吸急促为主要表现。其发病机制复杂,且具有异质性的特点,给诊断和治疗带来困难。代谢组学和脂质组学可以从机体内小分子代谢物及代谢通路水平探索哮喘的发病机制,指导诊断和治疗。同时,代谢组学和脂质组学符合中医学整体观念,适用于对中医证型客观化和标准化的研究,并为中医药治疗哮喘的可行性提供依据。该文对近年来代谢组学和脂质组学在生物标记物发现和代谢图谱构建的进展进行了综述,旨在为哮喘发病机制、诊断和治疗提供新思路。      

Diagnostic significance of plasma lipid markers and machine learning-based algorithm for gastric cancer

Biomarkers may be of value for the early detection of gastric cancer (GC) and the preoperative identification of tumor characteristics to guide treatment strategies. The present study analyzed the expression levels of phospholipids in plasma from patients with GC using liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) to detect reliable biomarkers for GC. Furthermore, combining the results with a machine learning strategy, the present study attempted to establish a diagnostic system for GC. A total of 20 plasma samples from preoperative patients with GC and 16 plasma samples from tumor-free patients (controls) were selected from our biobank named ‘SHINGEN (Yamanashi Biobank of Gastroenterological Cancers)’, which includes a total of 1,592 plasma samples, and were analyzed by LC/ESI-MS. The obtained data were discriminated using a machine learning-based diagnostic algorithm, whose discriminant ability was confirmed through leave-one-out cross-validation. Using LC/ESI-MS, the levels of 236 lipid molecules were determined. Biomarker analysis revealed that a few lipids that were downregulated in the GC group could discriminate between the GC and control groups. Whole lipid composition analysis using partial least squares regression revealed good discrimination ability between the GC and control groups. Integrative analysis of all molecules using the aforementioned machine learning method exhibited a diagnostic accuracy of 94.4% (specificity, 93.8%; sensitivity, 95.0%). In conclusion, the outcomes of the present study suggested the potential future application of the aforementioned system in clinical settings. By accumulating more reliable data, the present system will be able to detect early-stage cancer and will be capable of predicting the efficacy of each therapeutic strategy.     

Systems approach to inflammation resolution: identification of novel anti-inflammatory and pro-resolving mediators

Summary.  Using a systems approach to profile self-limited inflammatory exudates, we identified three novel families of lipid-derived mediators, coined the resolvins, protectins and most recently, the maresins that control both the magnitude and duration of inflammation. The mapping of these endogenous resolution circuits provides new avenues to probe the molecular basis of many widely occurring inflammatory diseases. This article focuses on our recent advances on the functional metabolomics of this novel genus of specialized pro-resolving mediators (SPM). SPM include resolvins, protectins and maresins and are biosynthesized from essential omega-3 fatty acid precursors. Each possesses potent multi-pronged actions that proved to be stereoselective with human cells and in animal disease models. Resolvins and protectins are also produced in bone marrow. Together, these findings suggest that defective resolution mechanism(s) may underlie some chronic inflammatory diseases. Moreover, identification of functional SPM biosynthesized during inflammation-resolution indicates that resolution is an active process.     

Untargeted Lipidomics of Vesicular Stomatitis Virus-Infected Cells and Viral Particles

The viral lifecycle is critically dependent upon host lipids. Enveloped viral entry requires fusion between viral and cellular membranes. Once an infection has occurred, viruses may rely on host lipids for replication and egress. Upon exit, enveloped viruses derive their lipid bilayer from host membranes during the budding process. Furthermore, host lipid metabolism and signaling are often hijacked to facilitate viral replication. We employed an untargeted HILIC-IM-MS lipidomics approach and identified host lipid species that were significantly altered during vesicular stomatitis virus (VSV) infection. Many glycerophospholipid and sphingolipid species were modified, and ontological enrichment analysis suggested that the alterations to the lipid profile change host membrane properties. Lysophosphatidylcholine (LPC), which can contribute to membrane curvature and serve as a signaling molecule, was depleted during infection, while several ceramide sphingolipids were augmented during infection. Ceramide and sphingomyelin lipids were also enriched in viral particles, indicating that sphingolipid metabolism is important during VSV infection.     

Healthy Breastfeeding Infants Consume Different Quantities of Milk Fat Globule Membrane Lipids

The human milk fat globule membrane (MFGM) contains important lipids for growing infants. Anthropometric measurements, milk samples, and infant milk intake were collected in a cohort of eleven healthy mother–infant dyads during exclusive breastfeeding from birth to six months. One hundred and sixty-six MFGM lipids were analysed using liquid chromatography-mass spectrometry, and the infant intake was calculated. The concentrations and intake were compared and associations between infant intake and growth characteristics explored. The lipid concentrations and infant intake varied widely between mother–infant dyads and between months one and three. The infant intake for many species displayed positive correlations with infant growth, particularly phospholipid species. The high variation in lipid intake is likely an important factor in infant growth, with strong correlations identified between the intake of many MFGM lipids and infant head circumference and weight. This study highlights the need for intake measurements and inclusion in cohort studies to elucidate the role of the human milk lipidome in infant growth and development.     

A review of the role of sebum in the mechanism of acne pathogenesis

Acne is one of the most common skin disorders, and its occurrence is closely related to many factors, including sebum secretion, hormone levels, bacterial infection, and inflammatory reactions. Among these, changes in sebum secretion are believed to be one important factor of acne. Increased sebum secretion can induce acne occurrence, and increasing evidence indicates sebum component changes are also strongly related to acne occurrence. Recently, developments in lipidomics have provided effective lipid analysis methods. These can help elucidate the effects of different types of sebum on acne occurrence and provide a theoretical basis for research on the mechanisms of acne pathogenesis and treatment.     

Association Between Circulating Lipids and Future Weight Gain in Individuals With an At-Risk Mental State and in First-Episode Psychosis

Patients with schizophrenia have a lower than average life span, largely due to the increased prevalence of cardiometabolic comorbidities. There is an unmet public health need to identify individuals with psychotic disorders who have a high risk of rapid weight gain and who are at risk of developing metabolic complications. Here, we applied mass spectrometry-based lipidomics in a prospective study comprising 48 healthy controls (CTR), 44 first-episode psychosis (FEP) patients, and 22 individuals at clinical high risk (CHR) for psychosis, from 2 study centers (Turku, Finland and London, UK). Baseline serum samples were analyzed using lipidomics, and body mass index (BMI) was assessed at baseline and after 12 months. We found that baseline triacylglycerols (TGs) with low double-bond counts and carbon numbers were positively associated with the change in BMI at follow-up. In addition, a molecular signature comprised of 2 TGs (TG[48:0] and TG[45:0]) was predictive of weight gain in individuals with a psychotic disorder, with an area under the receiver operating characteristic curve (AUROC) of 0.74 (95% CI: 0.60–0.85). When independently tested in the CHR group, this molecular signature predicted said weight change with AUROC = 0.73 (95% CI: 0.61–0.83). We conclude that molecular lipids may serve as a predictor of weight gain in psychotic disorders in at-risk individuals and may thus provide a useful marker for identifying individuals who are most prone to developing cardiometabolic comorbidities.