A lipidomic approach to the study of human CD4(+) T lymphocytes in multiple sclerosis

The involvement of the mitochondrial membrane in drug delivery

Treatment effectiveness and biosafety are critical for disease therapy. Bio-membrane modification facilitates the homologous targeting of drugs in vivo by exploiting unique antibodies or antigens, thereby enhancing therapeutic efficacy while ensuring biosafety. To further enhance the precision of disease treatment, future research should shift focus from targeted cellular delivery to targeted subcellular delivery. As the cellular powerhouses, mitochondria play an indispensable role in cell growth and regulation and are closely involved in many diseases (e.g., cancer, cardiovascular, and neurodegenerative diseases). The double-layer membrane wrapped on the surface of mitochondria not only maintains the stability of their internal environment but also plays a crucial role in fundamental biological processes, such as energy generation, metabolite transport, and information communication. A growing body of evidence suggests that various diseases are tightly related to mitochondrial imbalance. Moreover, mitochondria-targeted strategies hold great potential to decrease therapeutic threshold dosage, minimize side effects, and promote the development of precision medicine. Herein, we introduce the structure and function of mitochondrial membranes, summarize and discuss the important role of mitochondrial membrane-targeting materials in disease diagnosis/treatment, and expound the advantages of mitochondrial membrane-assisted drug delivery for disease diagnosis, treatment, and biosafety. This review helps readers understand mitochondria-targeted therapies and promotes the application of mitochondrial membranes in drug delivery. STATEMENT OF SIGNIFICANCE: Bio-membrane modification facilitates the homologous targeting of drugs in vivo by exploiting unique antibodies or antigens, thereby enhancing therapeutic efficacy while ensuring biosafety. Compared to cell-targeted treatment, targeting of mitochondria for drug delivery offers higher efficiency and improved biosafety and will promote the development of precision medicine. As a natural material, the mitochondrial membrane exhibits excellent biocompatibility and can serve as a carrier for mitochondria-targeted delivery. This review provides an overview of the structure and function of mitochondrial membranes and explores the potential benefits of utilizing mitochondrial membrane-assisted drug delivery for disease treatment and biosafety. The aim of this review is to enhance readers' comprehension of mitochondrial targeted therapy and to advance the utilization of mitochondrial membrane in drug delivery.

Mitochondrial and metabolic dysfunction of peripheral immune cells in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by the infiltration of inflammatory cells and demyelination of nerves. Mitochondrial dysfunction has been implicated in the pathogenesis of MS, as studies have shown abnormalities in mitochondrial activities, metabolism, mitochondrial DNA (mtDNA) levels, and mitochondrial morphology in immune cells of individuals with MS. The presence of mitochondrial dysfunctions in immune cells contributes to immunological dysregulation and neurodegeneration in MS. This review provided a comprehensive overview of mitochondrial dysfunction in immune cells associated with MS, focusing on the potential consequences of mitochondrial metabolic reprogramming on immune function. Current challenges and future directions in the field of immune-metabolic MS and its potential as a therapeutic target were also discussed.

Changes in Plasma Phospholipid Metabolism Are Associated with Clinical Manifestations of Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease with fibrosis of the skin and/or internal organs, causing a decrease in quality of life and survival. There is no causative therapy, and the pathophysiology of the SSc remains unclear. Studies showed that lipid metabolism was relevant for autoimmune diseases, but little is known about the role of lipids in SSc. In the present study, we sought to explore the phospholipid profile of SSc by using the lipidomics approach. We also aimed to analyze lipidomics results for different clinical manifestations of SSc. Experiments were performed using high-performance liquid chromatography coupled to mass spectrometry for the lipidomic profiling of plasma samples from patients with SSc. Our study showed, for the first time, significant changes in the level of phospholipids such as plasmalogens and sphingomyelins from the plasma of SSc patients as compared to controls. Phosphatidylcholine plasmalogens species and sphingomyelins were significantly increased in SSc patients as compared to controls. Our results also demonstrated a significant association of changes in the metabolism of phospholipids (phosphatidylcholine and phosphatidylethanolamine plasmalogens species and sphingomyelins) with different clinical manifestations of SSc. Further lipidomic studies might lead to the detection of lipids as new biomarkers or therapeutic targets of SSc.

Carbohydrate and lipid metabolism in multiple sclerosis: Clinical implications for etiology, pathogenesis, diagnosis, prognosis, and therapy

Multiple sclerosis (MS) is a complicated autoimmune disease characterized by inflammatory and demyelinating events in the central nervous system. The exact etiology and pathogenesis of MS have not been elucidated. However, a set of metabolic changes and their effects on immune cells and neural functions have been explained. This review highlights the contribution of carbohydrates and lipids metabolism to the etiology and pathogenesis of MS. Then, we have proposed a hypothetical relationship between such metabolic changes and the immune system in patients with MS. Finally, the potential clinical implications of these metabolic changes in diagnosis, prognosis, and discovering therapeutic targets have been discussed. It is concluded that research on the pathophysiological alterations of carbohydrate and lipid metabolism may be a potential strategy for paving the way toward MS treatment.

Disrupted Lipid Metabolism in Multiple Sclerosis: A Role for Liver X Receptors?

Multiple sclerosis (MS) is a chronic neurological disease driven by autoimmune, inflammatory and neurodegenerative processes leading to neuronal demyelination and subsequent degeneration. Systemic lipid metabolism is disturbed in people with MS, and lipid metabolic pathways are crucial to the protective process of remyelination. The lipid-activated transcription factors liver X receptors (LXRs) are important integrators of lipid metabolism and immunity. Consequently, there is a strong interest in targeting these receptors in a number of metabolic and inflammatory diseases, including MS. We have reviewed the evidence for involvement of LXR-driven lipid metabolism in the dysfunction of peripheral and brain-resident immune cells in MS, focusing on human studies, both the relapsing remitting and progressive phases of the disease are discussed. Finally, we discuss the therapeutic potential of modulating the activity of these receptors with existing pharmacological agents and highlight important areas of future research.

Metabolomic Biomarkers of Multiple Sclerosis: A Systematic Review

Background

Magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, and the McDonald’s clinical criteria are currently utilized tools in diagnosing multiple sclerosis. However, a more conclusive, consistent, and efficient way of diagnosing multiple sclerosis (MS) is yet to be discovered. A potential biomarker, discovered using advances in high-throughput sequencing such as nuclear magnetic resonance (NMR) spectroscopy and other “Omics”-based techniques, may make diagnosis and prognosis more reliable resulting in a more personalized and targeted treatment regime and improved outcomes. The aim of this review was to systematically search the literature for potential biomarkers from any bodily fluid that could consistently and accurately diagnose MS and/or indicate disease progression.

Methods

A systematic literature review of EMBASE, PubMed (MEDLINE), The Cochrane Library, and CINAHL databases produced over a thousand potential studies. Inclusion criteria stated studies with potential biomarker outcomes for people with MS were to be included in the review. Studies were limited to those with human participants who had a clinically defined diagnosis of MS and published in English, with no limit placed on date of publication or the type of bodily fluid sampled.

Results

A total of 1,805 studies were recorded from the literature search. A total of 1,760 studies were removed based on their abstract, with a further 18 removed after considering the full text. A total of 30 studies were considered relevant and had their data retrieved and analyzed. Due to the heterogeneity of focus and results from the refined studies, a narrative synthesis was favored.

Conclusion

Several promising candidate biomarkers suitable for clinical application in MS have been studied. It is recommended follow-up studies with larger sample sizes be completed on several potential biomarkers.

Systems biology approaches to study lipidomes in health and disease

Lipids have many important biological roles, such as energy storage sources, structural components of plasma membranes and as intermediates in metabolic and signaling pathways. Lipid metabolism is under tight homeostatic control, exhibiting spatial and dynamic complexity at multiple levels. Consequently, lipid-related disturbances play important roles in the pathogenesis of most of the common diseases. Lipidomics, defined as the study of lipidomes in biological systems, has emerged as a rapidly-growing field. Due to the chemical and functional diversity of lipids, the application of a systems biology approach is essential if one is to address lipid functionality at different physiological levels. In parallel with analytical advances to measure lipids in biological matrices, the field of computational lipidomics has been rapidly advancing, enabling modeling of lipidomes in their pathway, spatial and dynamic contexts. This review focuses on recent progress in systems biology approaches to study lipids in health and disease, with specific emphasis on methodological advances and biomedical applications.

Metabolic determinants of leukocyte pathogenicity in neurological diseases

Neuroinflammatory and neurodegenerative diseases are characterized by the recruitment of circulating blood-borne innate and adaptive immune cells into the central nervous system (CNS). These leukocytes sustain the detrimental response in the CNS by releasing pro-inflammatory mediators that induce activation of local glial cells, blood-brain barrier (BBB) dysfunction, and neural cell death. However, infiltrating peripheral immune cells could also dampen CNS inflammation and support tissue repair. Recent advances in the field of immunometabolism demonstrate the importance of metabolic reprogramming for the activation and functionality of such innate and adaptive immune cell populations. In particular, an increasing body of evidence suggests that the activity of metabolites and metabolic enzymes could influence the pathogenic potential of immune cells during neuroinflammatory and neurodegenerative disorders. In this review, we discuss the role of intracellular metabolic cues in regulating leukocyte-mediated CNS damage in Alzheimer's and Parkinson's disease, multiple sclerosis and stroke, highlighting the therapeutic potential of drugs targeting metabolic pathways for the treatment of neurological diseases.

Lipidomic UPLC-MS/MS Profiles of Normal-Appearing White Matter Differentiate Primary and Secondary Progressive Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative inflammatory disease where an autoimmune response to components of the central nervous system leads to a loss of myelin and subsequent neurological deterioration. People with MS can develop primary or secondary progressive disease (PPMS, SPMS) and differentiation of the specific differences in the pathogenesis of these two courses, at the molecular level, is currently unclear. Recently, lipidomics studies using human biofluids, mainly plasma and cerebrospinal fluid, have highlighted a possible role for lipids in the initiation and progression of MS. However, there is a lack of lipidomics studies in MS on CNS tissues, such as normal-appearing white matter (NAWM), where local inflammation initially occurs. Herein, we developed an untargeted reverse phase ultra-performance liquid chromatography time of flight tandem mass spectrometry (RP-UPLC-TOF MS^E)-based workflow, in combination with multivariate and univariate statistical analysis, to assess significant differences in lipid profiles in brain NAWM from post-mortem cases of PPMS, SPMS and controls. Groups of eight control, nine PPMS and seven SPMS NAWM samples were used. Correlation analysis of the identified lipids by RP-UPLC-TOF MS^E was undertaken to remove those lipids that correlated with age, gender and post-mortem interval as confounding factors. We demonstrate that there is a significantly altered lipid profile of control cases compared with MS cases and that progressive disease, PPMS and SPMS, can be differentiated on the basis of the lipidome of NAWM with good sensitivity, specificity and prediction accuracy based on receiver operating characteristic (ROC) curve analysis. Metabolic pathway analysis revealed that the most altered lipid pathways between PPMS and SPMS were glycerophospholipid metabolism, glycerophosphatidyl inositol (GPI) anchor synthesis and linoleic acid metabolism. Further understanding of the impact of these lipid alterations described herein associated with progression will provide an increased understanding of the mechanisms underpinning progression and highlight possible new therapeutic targets.

An overview of lipidomic analysis in different human matrices of multiple sclerosis

Multiple sclerosis is a chronic inflammatory and neurodegenerative disease of the central nervous system, and it is one of the most common neurological cause of disability in young adults. It is known that several factors contribute to increase the risk of development and pathogenesis of multiple sclerosis, nonetheless, but the true etiology of this pathology remains unknown. Similar to other inflammatory diseases, oxidative stress and lipid peroxidation are also associated to multiple sclerosis. Alterations in the lipid profile seem to be a hallmark of this pathology which can contribute to the dysregulation of lipid homeostasis and lipid metabolism in multiple sclerosis. Lipidomic studies analysed in this review clearly demonstrate the role of lipids in inflammatory processes, in immunity, and in the onset and development of multiple sclerosis. Several investigations reported alterations of some molecular lipid species, in particular, with decrease of fatty acids (FA) 18:2 and 20:4 and total polyunsaturated FA, with compensatory increases of saturated FA with shorter carbon chains. Oxidized phospholipids were reported in few studies as well. Also, it was shown that clinical lipidomics has potential as a tool to aid both in multiple sclerosis diagnosis and therapeutics by allowing a detailed lipidome profiling of the patients suffering with this disease.

Current Progress of Lipid Analysis in Metabolic Diseases by Mass Spectrometry Methods

BACKGROUND

Obesity, insulin resistance, diabetes, and metabolic syndrome are associated with lipid alterations, and they affect the risk of long-term cardiovascular disease. A reliable analytical instrument to detect changes in the composition or structures of lipids and the tools allowing to connect changes in a specific group of lipids with a specific disease and its progress, is constantly lacking. Lipidomics is a new field of medicine based on the research and identification of lipids and lipid metabolites present in human organism. The primary aim of lipidomics is to search for new biomarkers of different diseases, mainly civilization diseases.

OBJECTIVE

We aimed to review studies reporting the application of mass spectrometry for lipid analysis in metabolic diseases.

METHOD

Following an extensive search of peer-reviewed articles on the mass spectrometry analysis of lipids the literature has been discussed in this review article.

RESULTS

The lipid group contains around 1.7 million species; they are totally different, in terms of the length of aliphatic chain, amount of rings, additional functional groups. Some of them are so complex that their complex analyses are a challenge for analysts. Their qualitative and quantitative analysis of is based mainly on mass spectrometry.

CONCLUSION

Mass spectrometry techniques are excellent tools for lipid profiling in complex biological samples and the combination with multivariate statistical analysis enables the identification of potential diagnostic biomarkers.

Mitochondrial Reactive Oxygen Species and Type 1 Diabetes

SIGNIFICANCE

The complex etiology of type 1 diabetes (T1D) is the outcome of failures in regulating immunity in combination with beta cell perturbations. Mitochondrial dysfunction in beta cells and immune cells may be involved in T1D pathogenesis. Mitochondrial energy production is essential for the major task of beta cells (the secretion of insulin in response to glucose). Mitochondria are a major site of reactive oxygen species (ROS) production. Under immune attack, mitochondrial ROS (mtROS) participate in beta cell damage. Similarly, T cell fate during immune responses is tightly regulated by mitochondrial physiology, morphology, and metabolism. Production of mtROS is essential for signaling in antigen-specific T cell activation. Mitochondrial dysfunction in T cells has been noted as a feature of some human autoimmune diseases. Recent Advances: Preclinical and clinical studies indicate that mitochondrial dysfunction in beta cells sensitizes these cells to immune-mediated destruction via direct or indirect mechanisms. Sensitivity of beta cells to mtROS is associated with genetic T1D risk loci in human and the T1D-prone nonobese diabetic (NOD) mouse. Mitochondrial dysfunction and altered metabolism have also been observed in immune cells of NOD mice and patients with T1D. This immune cell mitochondrial dysfunction has been linked to deleterious functional changes.

CRITICAL ISSUES

It remains unclear how mitochondria control T cell receptor signaling and downstream events, including calcium flux and activation of transcription factors during autoimmunity.

FUTURE DIRECTIONS

Mechanistic studies are needed to investigate the mitochondrial pathways involved in autoimmunity, including T1D. These studies should seek to identify the role of mitochondria in regulating innate and adaptive immune cell activity and beta cell failure.

Mitochondria, Oxidative Stress and Innate Immunity

Canonical functions of mitochondria include the regulation of cellular survival, orchestration of anabolic and metabolic pathways, as well as reactive oxygen species (ROS) signaling. Recent discoveries, nevertheless, have demonstrated that mitochondria are also critical elements to stimulate innate immune signaling cascade that is able to intensify the inflammation upon cytotoxic stimuli beyond microbial infection. Here we review the expanding research field of mitochondria and oxidative stress in innate immune system to highlight the new mechanistic insights and discuss the pathological relevance of mitochondrial dysregulation induced aberrant innate immune responses in a growing list of sterile inflammatory diseases.

IL-17-triggered downregulation of miR-497 results in high HIF-1α expression and consequent IL-1β and IL-6 production by astrocytes in EAE mice

Interleukin 17 (IL-17) is increasingly recognized as a key factor that contributes to the pathogenesis of multiple sclerosis (MS) and its experimental mouse autoimmune encephalomyelitis (EAE) model. However, the roles and regulatory mechanisms of IL-17-induced pro-inflammatory cytokine production in EAE mice remain largely unclear. In this study, the expression of IL-17, hypoxia inducible factor-1α (HIF-1α), IL-1β, IL-6 and microRNA-497 (miR-497), as well as their intrinsic associations, was investigated using EAE model mice and cultured astrocytes exposed to IL-17 in vitro. We observed markedly increased production of IL-17, HIF-1α, IL-1β and IL-6 in the brain tissues of EAE mice, while the expression and secretion of HIF-1α, IL-1β and IL-6 were also significantly increased when cultured primary astrocytes from mice were stimulated with IL-17. Meanwhile, the expression of miR-497 was downregulated both in vivo and in vitro. Subsequent in vitro experiments revealed that IL-17 induced the production of IL-1β and IL-6 in astrocytes through the upregulation of HIF-1α as a transcriptional factor, indicating that IL-17-mediated downregulation of miR-497 enhanced HIF-1α expression. Furthermore, astrocyte-specific knockdown of IL-17RA and HIF-1α or astrocyte-specific overexpression of miR-497 by infection with different lentiviral vectors containing an astrocyte-specific promotor markedly decreased IL-1β and IL-6 production in brain tissues and alleviated the pathological changes and score of EAE mice. Collectively, these findings indicate that decreased miR-497 expression is responsible for IL-17-triggered high HIF-1α expression and consequent IL-1β and IL-6 production by astrocytes in EAE mice.Cellular & Molecular Immunology advance online publication, 1 May 2017; doi:10.1038/cmi.2017.12.

LipidPioneer : A Comprehensive User-Generated Exact Mass Template for Lipidomics

Lipidomics, the comprehensive measurement of lipid species in a biological system, has promising potential in biomarker discovery and disease etiology elucidation. Advances in chromatographic separation, mass spectrometric techniques, and novel substrate applications continue to expand the number of lipid species observed. The total number and type of lipid species detected in a given sample are generally indicative of the sample matrix examined (e.g., serum, plasma, cells, bacteria, tissue, etc.). Current exact mass lipid libraries are static and represent the most commonly analyzed matrices. It is common practice for users to manually curate their own lists of lipid species and adduct masses; however, this process is time-consuming. LipidPioneer, an interactive template, can be used to generate exact masses and molecular formulas of lipid species that may be encountered in the mass spectrometric analysis of lipid profiles. Over 60 lipid classes are present in the LipidPioneer template and include several unique lipid species, such as ether-linked lipids and lipid oxidation products. In the template, users can add any fatty acyl constituents without limitation in the number of carbons or degrees of unsaturation. LipidPioneer accepts naming using the lipid class level (sum composition) and the LIPID MAPS notation for fatty acyl structure level. In addition to lipid identification, user-generated lipid m/z values can be used to develop inclusion lists for targeted fragmentation experiments. Resulting lipid names and m/z values can be imported into software such as MZmine or Compound Discoverer to automate exact mass searching and isotopic pattern matching across experimental data. Graphical Abstract ᅟ.