101
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Assmann N, Finlay DK. Metabolic regulation of immune responses: therapeutic opportunities. J Clin Invest 2016; 126:2031-9. [PMID: 27249676 DOI: 10.1172/jci83005] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Immune cell metabolism is dynamically regulated in parallel with the substantial changes in cellular function that accompany immune cell activation. While these changes in metabolism are important for facilitating the increased energetic and biosynthetic demands of activated cells, immune cell metabolism also has direct roles in controlling the functions of immune cells and shaping the immune response. A theme is emerging wherein nutrients, metabolic enzymes, and metabolites can act as an extension of the established immune signal transduction pathways, thereby adding an extra layer of complexity to the regulation of immunity. This Review will outline the metabolic configurations adopted by different immune cell subsets, describe the emerging roles for metabolic enzymes and metabolites in the control of immune cell function, and discuss the therapeutic implications of this emerging immune regulatory axis.
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102
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Guma M, Tiziani S, Firestein GS. Metabolomics in rheumatic diseases: desperately seeking biomarkers. Nat Rev Rheumatol 2016; 12:269-81. [PMID: 26935283 PMCID: PMC4963238 DOI: 10.1038/nrrheum.2016.1] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Metabolomics enables the profiling of large numbers of small molecules in cells, tissues and biological fluids. These molecules, which include amino acids, carbohydrates, lipids, nucleotides and their metabolites, can be detected quantitatively. Metabolomic methods, often focused on the information-rich analytical techniques of NMR spectroscopy and mass spectrometry, have potential for early diagnosis, monitoring therapy and defining disease pathogenesis in many therapeutic areas, including rheumatic diseases. By performing global metabolite profiling, also known as untargeted metabolomics, new discoveries linking cellular pathways to biological mechanisms are being revealed and are shaping our understanding of cell biology, physiology and medicine. These pathways can potentially be targeted to diagnose and treat patients with immune-mediated diseases.
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Affiliation(s)
- Monica Guma
- Division of Rheumatology, Allergy and Immunology, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, California 92093-0656, USA
| | - Stefano Tiziani
- Department of Nutritional Sciences, University of Texas at Austin, 1400 Barbara Jordan Boulevard, Austin, Texas 78723, USA
| | - Gary S Firestein
- Division of Rheumatology, Allergy and Immunology, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, California 92093-0656, USA
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Abstract
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by a loss of tolerance to multiple endogenous antigens. SLE etiology remains largely unknown, despite recent insight into the immunopathogenesis of the disease. T cells are important in the development of the disease by amplifying the immune response and contributing to organ damage. Aberrant signaling, cytokine secretion, and tissue homing displayed by SLE T cells have been extensively studied and the underlying pathogenic molecular mechanisms are starting to be elucidated. T-cell-targeted treatments are being explored in SLE patients. This review is an update on the T-cell abnormalities and related therapeutic options in SLE.
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Affiliation(s)
- D Comte
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - M P Karampetsou
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - G C Tsokos
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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104
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Lactosylceramide-accumulation in lipid-rafts mediate aberrant-autophagy, inflammation and apoptosis in cigarette smoke induced emphysema. Apoptosis 2015; 20:725-39. [PMID: 25638276 DOI: 10.1007/s10495-015-1098-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ceramide-accumulation is known to be involved in the pathogenesis of chronic inflammatory lung diseases including cigarette smoke-induced emphysema (CS-emphysema) but the exact sphingolipid metabolite that initiates emphysema progression remains ambiguous. We evaluated here a novel role for the sphingolipid, lactosylceramide (LacCer), as a potential mechanism for pathogenesis of CS-emphysema. We assessed the expression of LacCer, and LacCer-dependent inflammatory, apoptosis and autophagy responses in lungs of mice exposed to CS, as well as peripheral lung tissues from COPD subjects followed by experimental analysis to verify the role of LacCer in CS-emphysema. We observed significantly elevated LacCer-accumulation in human COPD lungs with increasing severity of emphysema over non-emphysema controls. Moreover, increased expression of defective-autophagy marker, p62, in lung tissues of severe COPD subjects suggest that LacCer induced aberrant-autophagy may contribute to the pathogenesis of CS-emphysema. We verified that CS-extract treatment significantly induces LacCer-accumulation in both bronchial-epithelial cells (BEAS2B) and macrophages (Raw264.7) as a mechanism to initiate aberrant-autophagy (p62-accumulation) and apoptosis that was rescued by pharmacological inhibitor of LacCer-synthase. Further, we corroborated that CS exposure induces LacCer-accumulation in murine lungs that can be controlled by LacCer-synthase inhibitor. We propose LacCer-accumulation as a novel prognosticator of COPD-emphysema severity, and provide evidence on the therapeutic efficacy of LacCer-synthase inhibitor in CS induced COPD-emphysema.
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105
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Regulation of Adaptive Immunity in Health and Disease by Cholesterol Metabolism. Curr Allergy Asthma Rep 2015; 15:48. [PMID: 26149587 DOI: 10.1007/s11882-015-0548-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Four decades ago, it was observed that stimulation of T cells induces rapid changes in cellular cholesterol that are required before proliferation can commence. Investigators returning to this phenomenon have finally revealed its molecular underpinnings. Cholesterol trafficking and its dysregulation are now also recognized to strongly influence dendritic cell function, T cell polarization, and antibody responses. In this review, the state of the literature is reviewed on how cholesterol and its trafficking regulate the cells of the adaptive immune response and in vivo disease phenotypes of dysregulated adaptive immunity, including allergy, asthma, and autoimmune disease. Emerging evidence supporting a potential role for statins and other lipid-targeted therapies in the treatment of these diseases is presented. Just as vascular biologists have embraced immunity in the pathogenesis and treatment of atherosclerosis, so should basic and clinical immunologists in allergy, pulmonology, and other disciplines seek to encompass a basic understanding of lipid science.
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106
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Zhang X, Zhang D, Liu W, Li H, Fu R, Liu X, Xue F, Yang R. Abnormal lipid rafts related ganglioside expression and signaling in T lymphocytes in immune thrombocytopenia patients. Autoimmunity 2015; 49:58-68. [PMID: 26287565 DOI: 10.3109/08916934.2015.1070837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Aberrant T lymphocytes signaling is considered to play a crucial role in the abnormal immune state of primary immune thrombocytopenia (ITP). Lipid raft has been verified to engage in the T cell receptor (TCR)-mediated T lymphocytes signal transduction. Whether lipid raft-associated T cells signal transduction has impact on the pathogenesis of ITP is still unconfirmed. In this study, we aimed to reveal the abnormality in structure and function of lipid rafts (LRs) in CD4(+) and CD8(+) T lymphocytes of patients with ITP. Our results showed that there was an increased lipid raft aggregation in ITP patients, while this kind of increase would not be influenced by platelet counts or therapeutic regimes. Stimulation by anti-CD3/CD28 monoclonal antibodies promoted enhanced lipid raft clustering in T lymphocytes of ITP patients compared with negative controls. Methyl-β-cyclodextrin (MβCD) could block the abnormal lipid raft aggregation and disrupt the TCR-mediated T cells proliferation and cytokines secretion, including both proinflammatory cytokines and anti-inflammatory cytokines. The spontaneous activation of T lymphocytes from ITP patients might be due to the elevated co-localization of protein tyrosine phosphatase (PTP) CD45 and lipid rafts in patients' CD4(+) and CD8(+) T lymphocytes. These findings suggest that the autoactivation of T lymphocytes from ITP patients may lead to the abnormality in lipid raft structure and raft-anchored proteins, and the changes conversely promote the TCR-mediated T cells activation of ITP patients.
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Affiliation(s)
- Xian Zhang
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Donglei Zhang
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Wenjie Liu
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Huiyuan Li
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Rongfeng Fu
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Xiaofan Liu
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Feng Xue
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
| | - Renchi Yang
- a State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College , Tianjin , PR China
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107
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Manipulating membrane lipid profiles to restore T-cell function in autoimmunity. Biochem Soc Trans 2015; 43:745-51. [PMID: 26551723 DOI: 10.1042/bst20150111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 01/08/2023]
Abstract
Plasma membrane lipid rafts are heterogeneous cholesterol and glycosphingolipid (GSL)-enriched microdomains, within which the tight packing of cholesterol with the saturated-acyl chains of GSLs creates a region of liquid-order relative to the surrounding disordered membrane. Thus lipid rafts govern the lateral mobility and interaction of membrane proteins and regulate a plethora of signal transduction events, including T-cell antigen receptor (TCR) signalling. The pathways regulating homoeostasis of membrane cholesterol and GSLs are tightly controlled and alteration of these metabolic processes coincides with immune cell dysfunction as is evident in atherosclerosis, cancer and autoimmunity. Indeed, membrane lipid composition is emerging as an important factor influencing the ability of cells to respond appropriately to microenvironmental stimuli. Consequently, there is increasing interest in targeting membrane lipids or their metabolic control as a novel therapeutic approach to modulate immune cell behaviour and our recent work demonstrates that this is a promising strategy in T-cells from patients with the autoimmune disease systemic lupus erythematosus (SLE).
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108
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Abstract
The liver X receptors (LXRs), LXRα and LXRβ, are transcription factors with well-established roles in the regulation of lipid metabolism and cholesterol homeostasis. In addition, LXRs influence innate and adaptive immunity, including responses to inflammatory stimuli, proliferation and differentiation, migration, apoptosis and survival. However, the majority of work describing the role of LXRs in immune cells has been carried out in mouse models, and there are a number of known species-specific differences concerning LXR function. Here we review what is known about the role of LXRs in human immune cells, demonstrating the importance of these receptors in the integration of lipid metabolism and immune function, but also highlighting the need for a better understanding of the species, isoform, and cell-type specific effects of LXR activation.
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109
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Hou TY, McMurray DN, Chapkin RS. Omega-3 fatty acids, lipid rafts, and T cell signaling. Eur J Pharmacol 2015; 785:2-9. [PMID: 26001374 DOI: 10.1016/j.ejphar.2015.03.091] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 02/16/2015] [Accepted: 03/16/2015] [Indexed: 12/24/2022]
Abstract
n-3 polyunsaturated fatty acids (PUFA) have been shown in many clinical studies to attenuate inflammatory responses. Although inflammatory responses are orchestrated by a wide spectrum of cells, CD4(+) T cells play an important role in the etiology of many chronic inflammatory diseases such as inflammatory bowel disease and obesity. In light of recent concerns over the safety profiles of non-steroidal anti-inflammatory drugs (NSAIDs), alternatives such as bioactive nutraceuticals are becoming more attractive. In order for these agents to be accepted into mainstream medicine, however, the mechanisms by which nutraceuticals such as n-3 PUFA exert their anti-inflammatory effects must be fully elucidated. Lipid rafts are nanoscale, dynamic domains in the plasma membrane that are formed through favorable lipid-lipid (cholesterol, sphingolipids, and saturated fatty acids) and lipid-protein (membrane-actin cytoskeleton) interactions. These domains optimize the clustering of signaling proteins at the membrane to facilitate efficient cell signaling which is required for CD4(+) T cell activation and differentiation. This review summarizes novel emerging data documenting the ability of n-3 PUFA to perturb membrane-cytoskeletal structure and function in CD4(+) T cells. An understanding of these underlying mechanisms will provide a rationale for the use of n-3 PUFA in the treatment of chronic inflammation.
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Affiliation(s)
- Tim Y Hou
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA
| | - David N McMurray
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University System Health Science Center, College Station, TX, USA
| | - Robert S Chapkin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University System Health Science Center, College Station, TX, USA.
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110
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Effect of Leflunomide on the Abnormal Expression of Lipid Rafts and F-Actin in B Lymphocytes from Patients with Systemic Lupus Erythematosus. J Immunol Res 2015; 2015:832916. [PMID: 26090500 PMCID: PMC4452103 DOI: 10.1155/2015/832916] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 11/18/2022] Open
Abstract
Purposes. To investigate the possible changes in B cell subsets and in B cell expression patterns of lipid rafts (LRs) and F-actin in patients with SLE and whether leflunomide treatment may have effect on these changes. Methods. The B cell subsets and LRs expression were determined by flow cytometry and confocal microscopy, and F-actin expression was examined by confocal microscopy. Results. CD27+IgD+ B cell subsets were significantly decreased while CD38+CD95+ B cell subsets increased in SLE patients. The LRs levels of B cells were remarkably increased and positively correlated with SLEDAI and anti-dsDNA titer in SLE patients. The expression level of LRs was significantly higher in CD38+ B cells than CD38− B cells and negatively correlated with C3 levels. The increased expression of LRs was associated with reduced expression of F-actin in the B cells from active SLE patients. Furthermore, in vitro treatment of the cells with A771726 reduced the expression level of LRs, attenuated the overaggregation of LRs, and normalized the distribution of F-actin. Conclusions. There were abnormalities in B cell subsets and LRs and F-actin expression of B cell from SLE patients. Modulation of B cell expression of LRs and F-actin by LEF could be a potential therapeutic target for SLE.
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111
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Moulton VR, Tsokos GC. T cell signaling abnormalities contribute to aberrant immune cell function and autoimmunity. J Clin Invest 2015; 125:2220-7. [PMID: 25961450 DOI: 10.1172/jci78087] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a prototype systemic autoimmune disease that results from a break in immune tolerance to self-antigens, leading to multi-organ destruction. Autoantibody deposition and inflammatory cell infiltration in target organs such as kidneys and brain lead to complications of this disease. Dysregulation of cellular and humoral immune response elements, along with organ-defined molecular aberrations, form the basis of SLE pathogenesis. Aberrant T lymphocyte activation due to signaling abnormalities, linked to defective gene transcription and altered cytokine production, are important contributors to SLE pathophysiology. A better understanding of signaling and gene regulation defects in SLE T cells will lead to the identification of specific novel molecular targets and predictive biomarkers for therapy.
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112
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Abstract
Cancer cells have long been known to fuel their pathogenic growth habits by sustaining a high glycolytic flux, first described almost 90 years ago as the so-called Warburg effect. Immune cells utilize a similar strategy to generate the energy carriers and metabolic intermediates they need to produce biomass and inflammatory mediators. Resting lymphocytes generate energy through oxidative phosphorylation and breakdown of fatty acids, and upon activation rapidly switch to aerobic glycolysis and low tricarboxylic acid flux. T cells in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have a disease-specific metabolic signature that may explain, at least in part, why they are dysfunctional. RA T cells are characterized by low adenosine triphosphate and lactate levels and increased availability of the cellular reductant NADPH. This anti-Warburg effect results from insufficient activity of the glycolytic enzyme phosphofructokinase and differentiates the metabolic status in RA T cells from those in cancer cells. Excess production of reactive oxygen species and a defect in lipid metabolism characterizes metabolic conditions in SLE T cells. Owing to increased production of the glycosphingolipids lactosylceramide, globotriaosylceramide and monosialotetrahexosylganglioside, SLE T cells change membrane raft formation and fail to phosphorylate pERK, yet hyperproliferate. Borrowing from cancer metabolomics, the metabolic modifications occurring in autoimmune disease are probably heterogeneous and context dependent. Variations of glucose, amino acid and lipid metabolism in different disease states may provide opportunities to develop biomarkers and exploit metabolic pathways as therapeutic targets.
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Affiliation(s)
- Zhen Yang
- Department of Medicine, Stanford University School of Medicine, CCSR Building Rm 2225, 269 Campus Drive West, Stanford, CA, 94305-5166, USA.
| | - Eric L Matteson
- Division of Rheumatology, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA.
| | - Jörg J Goronzy
- Department of Medicine, Stanford University School of Medicine, CCSR Building Rm 2225, 269 Campus Drive West, Stanford, CA, 94305-5166, USA.
| | - Cornelia M Weyand
- Department of Medicine, Stanford University School of Medicine, CCSR Building Rm 2225, 269 Campus Drive West, Stanford, CA, 94305-5166, USA.
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113
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Yin Y, Choi SC, Xu Z, Perry DJ, Seay H, Croker BP, Sobel ES, Brusko TM, Morel L. Normalization of CD4+ T cell metabolism reverses lupus. Sci Transl Med 2015; 7:274ra18. [PMID: 25673763 PMCID: PMC5292723 DOI: 10.1126/scitranslmed.aaa0835] [Citation(s) in RCA: 460] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease in which autoreactive CD4(+) T cells play an essential role. CD4(+) T cells rely on glycolysis for inflammatory effector functions, but recent studies have shown that mitochondrial metabolism supports their chronic activation. How these processes contribute to lupus is unclear. We show that both glycolysis and mitochondrial oxidative metabolism are elevated in CD4(+) T cells from lupus-prone B6.Sle1.Sle2.Sle3 (TC) mice as compared to non-autoimmune controls. In vitro, both the mitochondrial metabolism inhibitor metformin and the glucose metabolism inhibitor 2-deoxy-d-glucose (2DG) reduced interferon-γ (IFN-γ) production, although at different stages of activation. Metformin also restored the defective interleukin-2 (IL-2) production by TC CD4(+) T cells. In vivo, treatment of TC mice and other lupus models with a combination of metformin and 2DG normalized T cell metabolism and reversed disease biomarkers. Further, CD4(+) T cells from SLE patients also exhibited enhanced glycolysis and mitochondrial metabolism that correlated with their activation status, and their excessive IFN-γ production was significantly reduced by metformin in vitro. These results suggest that normalization of T cell metabolism through the dual inhibition of glycolysis and mitochondrial metabolism is a promising therapeutic venue for SLE.
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Affiliation(s)
- Yiming Yin
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Seung-Chul Choi
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Zhiwei Xu
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Daniel J Perry
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Howard Seay
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Byron P Croker
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Eric S Sobel
- Division of Rheumatology and Clinical Immunology, Department of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Todd M Brusko
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Laurence Morel
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA.
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114
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Schiffmann R. The consequences of genetic and pharmacologic reduction in sphingolipid synthesis. J Inherit Metab Dis 2015; 38:77-84. [PMID: 25164785 DOI: 10.1007/s10545-014-9758-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
Abstract
A new therapy based on substrate synthesis reduction in sphingolipidoses is showing promise. The consequences of decreasing sphingolipid synthesis depend on the level at which synthetic blockage occurs and on the extent of the blockage. Complete synthetic blockage may be lethal if it includes all sphingolipids, such as in a global knockout of serine palmitoyltransferase. Partial inhibition of sphingolipid synthetic pathways is usually benign and may have beneficial effects in a number of lysosomal diseases and in more common pathologies, as seen in animal models for atherosclerosis, polycystic kidney disease, diabetes, and asthma. Studies of various forms of sphingolipid synthesis reduction serve to highlight not only the cellular role of these lipids but also the potential risks and therapeutic benefits of pharmacological agents to be used in therapy for human diseases.
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Affiliation(s)
- Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Research Institute, 3812 Elm Street, Dallas, TX, USA,
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115
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Allende ML, Proia RL. Simplifying complexity: genetically resculpting glycosphingolipid synthesis pathways in mice to reveal function. Glycoconj J 2014; 31:613-22. [PMID: 25351657 PMCID: PMC4245496 DOI: 10.1007/s10719-014-9563-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 10/03/2014] [Indexed: 11/30/2022]
Abstract
Glycosphingolipids (GSLs) are a group of plasma-membrane lipids notable for their extremely diverse glycan head groups. The metabolic pathways for GSLs, including the identity of the biosynthetic enzymes needed for synthesis of their glycans, are now well understood. Many of their cellular functions, which include plasma-membrane organization, regulation of cell signaling, endocytosis, and serving as binding sites for pathogens and endogenous receptors, have also been established. However, an understanding of their functions in vivo had been lagging. Studies employing genetic manipulations of the GSL synthesis pathways in mice have been used to systematically reduce the large numbers and complexity of GSL glycan structures, allowing the in vivo functions of GSLs to be revealed from analysis of the resulting phenotypes. Findings from these studies have produced a clearer picture of the role of GSLs in mammalian physiology, which is the topic of this review.
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Affiliation(s)
- Maria Laura Allende
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 10, Room 9D-06; 10 Center DR MSC 1821, Bethesda, MD, 20892-1821, USA
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116
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Guma M, Sanchez-Lopez E, Lodi A, Garcia-Carbonell R, Tiziani S, Karin M, Lacal JC, Firestein GS. Choline kinase inhibition in rheumatoid arthritis. Ann Rheum Dis 2014; 74:1399-407. [PMID: 25274633 DOI: 10.1136/annrheumdis-2014-205696] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/13/2014] [Indexed: 01/20/2023]
Abstract
OBJECTIVES Little is known about targeting the metabolome in non-cancer conditions. Choline kinase (ChoKα), an essential enzyme for phosphatidylcholine biosynthesis, is required for cell proliferation and has been implicated in cancer invasiveness. Aggressive behaviour of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) led us to evaluate whether this metabolic pathway could play a role in RA FLS function and joint damage. METHODS Choline metabolic profile of FLS cells was determined by (1)H magnetic resonance spectroscopy ((1)HMRS) under conditions of ChoKα inhibition. FLS function was evaluated using the ChoKα inhibitor MN58b (IC₅₀=4.2 μM). For arthritis experiments, mice were injected with K/BxN sera. MN58b (3 mg/kg) was injected daily intraperitoneal beginning on day 0 or day 4 after serum administration. RESULTS The enzyme is expressed in synovial tissue and in cultured RA FLS. Tumour necrosis factor (TNF) and platelet-derived growth factor (PDGF) stimulation increased ChoKα expression and levels of phosphocholine in FLS measured by Western Blot (WB) and metabolomic studies of choline-containing compounds in cultured RA FLS extracts respectively, suggesting activation of this pathway in RA synovial environment. A ChoKα inhibitor also suppressed the behaviour of cultured FLS, including cell migration and resistance to apoptosis, which might contribute to cartilage destruction in RA. In a passive K/BxN arthritis model, pharmacologic ChoKα inhibition significantly decreased arthritis in pretreatment protocols as well as in established disease. CONCLUSIONS These data suggest that ChoKα inhibition could be an effective strategy in inflammatory arthritis. It also suggests that targeting the metabolome can be a new treatment strategy in non-cancer conditions.
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Affiliation(s)
- M Guma
- Division of Rheumatology, Allergy and Immunology, UC San Diego School of Medicine, La Jolla, California, USA
| | - E Sanchez-Lopez
- Laboratory of Gene Regulation and Signal Transduction, UC San Diego School of Medicine, La Jolla, California, USA Departments of Pharmacology, UC San Diego School of Medicine, La Jolla, California, USA Pathology, UC San Diego School of Medicine, La Jolla, California, USA
| | - A Lodi
- Department of Nutritional Sciences & Dell Pediatric Research Institute, University of Texas at Austin, Austin, Texas, USA
| | - R Garcia-Carbonell
- Laboratory of Gene Regulation and Signal Transduction, UC San Diego School of Medicine, La Jolla, California, USA Departments of Pharmacology, UC San Diego School of Medicine, La Jolla, California, USA Pathology, UC San Diego School of Medicine, La Jolla, California, USA
| | - S Tiziani
- Department of Nutritional Sciences & Dell Pediatric Research Institute, University of Texas at Austin, Austin, Texas, USA
| | - M Karin
- Laboratory of Gene Regulation and Signal Transduction, UC San Diego School of Medicine, La Jolla, California, USA Departments of Pharmacology, UC San Diego School of Medicine, La Jolla, California, USA Pathology, UC San Diego School of Medicine, La Jolla, California, USA
| | - J C Lacal
- Division of Translational Oncology, Health Research Institute and University Hospital "Fundación Jiménez Díaz", Madrid, Spain
| | - G S Firestein
- Division of Rheumatology, Allergy and Immunology, UC San Diego School of Medicine, La Jolla, California, USA
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117
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Aberrant presentation of self-lipids by autoimmune B cells depletes peripheral iNKT cells. Cell Rep 2014; 9:24-31. [PMID: 25263549 DOI: 10.1016/j.celrep.2014.08.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/04/2014] [Accepted: 08/20/2014] [Indexed: 11/23/2022] Open
Abstract
Invariant natural killer T (iNKT) cells provide cognate help via CD1d to lipid antigen-presenting B cells for antibody production, but whether B cells reciprocally regulate iNKT cells remains largely unexplored. Here, we found peripheral, but not thymic, iNKT cells to be numerically reduced in autoimmune mice lacking Fas specifically in B cells. The residual iNKT cells were antigenically overstimulated, had altered cytokine production, and manifested enhanced proliferation and apoptosis. B cell-specific ablation of CD1d ameliorated these iNKT defects, suggesting that inappropriate presentation of CD1d-restricted self-lipids by autoimmune B cell-depleted peripheral iNKT cells. CD1d(+) autoimmune B cells have reduced α-galactosidase A expression and, as revealed by lipidomic profiling, altered lipidome with aberrant accumulation of certain self-lipids and reduction of others. These findings unveil a critical link between autoimmunity, B cell lipidome, and the maintenance of peripheral iNKT cells and highlight an essential homeostatic function of B cells beyond antibody production.
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Abstract
During infections or acute conditions high-density lipoproteins cholesterol (HDL-C) levels decrease very rapidly and HDL particles undergo profound changes in their composition and function. These changes are associated with poor prognosis following endotoxemia or sepsis and data from genetically modified animal models support a protective role for HDL. The same is true for some parasitic infections, where the key player appears to be a specific and minor component of HDL, namely apoL-1. The ability of HDL to influence cholesterol availability in lipid rafts in immune cells results in the modulation of toll-like receptors, MHC-II complex, as well as B- and T-cell receptors, while specific molecules shuttled by HDL such as sphingosine-1-phosphate (S1P) contribute to immune cells trafficking. Animal models with defects associated with HDL metabolism and/or influencing cell cholesterol efflux present features related to immune disorders. All these functions point to HDL as a platform integrating innate and adaptive immunity. The aim of this review is to provide an overview of the connection between HDL and immunity in atherosclerosis and beyond.
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Affiliation(s)
- Alberico Luigi Catapano
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, Milan 20133, Italy IRCCS Multimedica, Milan, Italy
| | - Angela Pirillo
- IRCCS Multimedica, Milan, Italy Center for the Study of Atherosclerosis, Ospedale Bassini, Cinisello Balsamo, Italy
| | - Fabrizia Bonacina
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, Milan 20133, Italy
| | - Giuseppe Danilo Norata
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, Milan 20133, Italy Center for the Study of Atherosclerosis, Ospedale Bassini, Cinisello Balsamo, Italy The Blizard Institute, Centre for Diabetes, Barts and The London School of Medicine & Dentistry, Queen Mary University, London, UK
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119
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Connective tissue diseases: Role for T cell lipid metabolism defects in SLE pathogenesis. Nat Rev Rheumatol 2014; 10:127. [PMID: 24514916 DOI: 10.1038/nrrheum.2014.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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120
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Kidani Y, Bensinger SJ. Lipids rule: resetting lipid metabolism restores T cell function in systemic lupus erythematosus. J Clin Invest 2014; 124:482-5. [PMID: 24463443 DOI: 10.1172/jci74141] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is a devastating autoimmune disease characterized by chronic inflammation and systemic destruction of host organs or tissue. A key feature of SLE is T cell dysfunction characterized by hyperresponsive antigen receptor signaling. In this issue of the JCI, McDonald and colleagues provide evidence that homeostasis of a subset of lipids, the glycosphingolipids (GSLs), is severely perturbed in the membranes of T cells from SLE patients. Furthermore, normalization of GSLs restored TCR signaling and ameliorated T cell dysfunction. These data suggest that targeting host metabolism may be an effective means of reinforcing self-tolerance and attenuating autoimmunity.
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