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Maula T, Al Sazzad MA, Slotte JP. Influence of Hydroxylation, Chain Length, and Chain Unsaturation on Bilayer Properties of Ceramides. Biophys J 2016; 109:1639-51. [PMID: 26488655 DOI: 10.1016/j.bpj.2015.08.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/14/2015] [Accepted: 08/31/2015] [Indexed: 11/29/2022] Open
Abstract
Mammalian ceramides constitute a family of at least a few hundred closely related molecules distinguished by small structural differences, giving rise to individual molecular species that are expressed in distinct cellular compartments, or tissue types, in which they are believed to execute distinct functions. We have examined how specific structural details influence the bilayer properties of a selection of biologically relevant ceramides in mixed bilayers together with sphingomyelin, phosphatidylcholine, and cholesterol. The ceramide structure varied with regard to interfacial hydroxylation, the identity of the headgroup, the length of the N-acyl chain, and the position of cis-double bonds in the acyl chains. The interactions of the ceramides with sphingomyelin, their lateral segregation into ceramide-rich domains in phosphatidylcholine bilayers, and the effect of cholesterol on such domains were studied with DSC and various fluorescence-based approaches. The largest differences arose from the presence and relative position of cis-double bonds, causing destabilization of the ceramide's interactions and lateral packing relative to common saturated and hydroxylated species. Less variation was observed as a consequence of interfacial hydroxylation and the N-acyl chain length, although an additional hydroxyl in the sphingoid long-chain base slightly destabilized the ceramide's interactions and packing relative to a nonhydroxyceramide, whereas an additional hydroxyl in the N-acyl chain had the opposite effect. In conclusion, small structural details conferred variance in the bilayer behavior of ceramides, some causing more dramatic changes in the bilayer properties, whereas others imposed only fine adjustments in the interactions of ceramides with other membrane lipids, reflecting possible functional implications in distinct cell or tissue types.
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Affiliation(s)
- Terhi Maula
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
| | - Md Abdullah Al Sazzad
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
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Vogt D, Stark H. Therapeutic Strategies and Pharmacological Tools Influencing S1P Signaling and Metabolism. Med Res Rev 2016; 37:3-51. [PMID: 27480072 DOI: 10.1002/med.21402] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 06/01/2016] [Accepted: 06/28/2016] [Indexed: 02/06/2023]
Abstract
During the last two decades the study of the sphingolipid anabolic, catabolic, and signaling pathways has attracted enormous interest. Especially the introduction of fingolimod into market as first p.o. therapeutic for the treatment of multiple sclerosis has boosted this effect. Although the complex regulation of sphingosine-1-phosphate (S1P) and other catabolic and anabolic sphingosine-related compounds is not fully understood, the influence on different (patho)physiological states from inflammation to cytotoxicity as well as the availability of versatile pharmacological tools that represent new approaches to study these states are described. Here, we have summarized various aspects concerning the many faces of sphingolipid function modulation by different pharmacological tools up to clinical candidates. Due to the immense heterogeneity of physiological or pharmacological actions and complex cross regulations, it is difficult to predict their role in upcoming therapeutic approaches. Currently, inflammatory, immunological, and/or antitumor aspects are discussed.
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Affiliation(s)
- Dominik Vogt
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, D-60438, Frankfurt, Germany
| | - Holger Stark
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany
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53
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Role of sphingomyelinase in mitochondrial ceramide accumulation during reperfusion. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1955-63. [PMID: 27479697 DOI: 10.1016/j.bbadis.2016.07.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 01/27/2023]
Abstract
Ceramide accumulation in mitochondria has been associated with reperfusion damage, but the underlying mechanisms are not clearly elucidated. In this work we investigate the role of sphingomyelinases in mitochondrial ceramide accumulation, its effect on reactive oxygen species production, as well as on mitochondrial function by using the sphingomyelinase inhibitor, tricyclodecan-9-yl-xanthogenate (D609). Correlation between neutral sphingomyelinase (nSMase) activity and changes in ceramide content were performed in whole tissue and in isolated mitochondria from reperfused hearts. Overall results demonstrated that D609 treatment attenuates cardiac dysfuncion, mitochondrial injury and oxidative stress. Ceramide was accumulated in mitochondria, but not in the microsomal fraction of the ischemic-reperfused (I/R) group. In close association, the activity of nSMase increased, whereas glutathione (GSH) levels diminished in mitochondria after reperfusion. On the other hand, reduction of ceramide levels in mitochondria from I/R+D609 hearts correlated with diminished nSMase activity, coupling of oxidative phosphorylation and with mitochondrial integrity maintenance. These results suggest that mitochondrial nSMase activity contributes to compartmentation and further accumulation of ceramide in mitochondria, deregulating their function during reperfusion.
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Tang Y, Cao K, Wang Q, Chen J, Liu R, Wang S, Zhou J, Xie H. Silencing of CerS6 increases the invasion and glycolysis of melanoma WM35, WM451 and SK28 cell lines via increased GLUT1-induced downregulation of WNT5A. Oncol Rep 2016; 35:2907-15. [PMID: 26934938 DOI: 10.3892/or.2016.4646] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/17/2015] [Indexed: 11/06/2022] Open
Abstract
Ceramide synthases (CerSs) have been shown to regulate numerous aspects of cancer development. CerS6 has been suggested to be involved in cancer etiology. However, little is known concerning the exact effect of CerS6 on the malignant behavior of melanoma, including glycolysis, proliferation and invasion. In the present study, we found that the expression of CerS6 was low in the melanoma cell lines, including WM35, WM451 and SK-28, and the expression level was related to the malignanct behavior of the melanoma cell lines. We constructed overexpression and silencing models of CerS6 in three melanoma cell lines and found that silencing of CerS6 promoted the ability of proliferation and invasion in the melanoma cell lines. Additionally, downregulation of CerS6 upregulated the activity of glycolysis-related enzyme, and enhanced the expression of glycolysis-related genes, including GLUT1 and MCT1. Furthermore, we identified the genes whose expression levels were changed after silencing of CerS6 by gene microarray. The expression of glycolysis-related gene SLC2A1 (also known as GLUT1) was found to be upregulated, while notably WNT5A was downregulated. The altered expression of GLUT1 and WNT5A was verified by qPCR and western blotting. Furthermore, silencing of GLUT1 in the melanoma cells resulted in the increased expression of WNT5A and the decreased ability of invasion and proliferation in the melanoma cells. Collectively, silencing of CerS6 induced the increased expression of GLUT1, which downregulated the expression of WNT5A and enhanced the invasion and proliferation of melanoma cells. Thus, CerS6 may provide a novel therapeutic target for melanoma treatment.
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Affiliation(s)
- Yuanyuan Tang
- Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Ke Cao
- Department of Oncology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Qi Wang
- Department of Oncology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Jia Chen
- Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Rui Liu
- Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Shaohua Wang
- Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Jianda Zhou
- Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Huiqing Xie
- Department of Rehabilitation, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
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Jung JS, Choi MJ, Ko HM, Kim HS. Short-chain C2 ceramide induces heme oxygenase-1 expression by upregulating AMPK and MAPK signaling pathways in rat primary astrocytes. Neurochem Int 2016; 94:39-47. [PMID: 26873583 DOI: 10.1016/j.neuint.2016.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 11/15/2022]
Abstract
Ceramide belongs to the group of sphingolipid metabolites that are produced in the brain and peripheral systems and act as intracellular second messengers. Although some physiological roles of ceramide have been reported in the brain, the role of ceramide in astrocytes has not been clearly demonstrated. In the present study, we investigated the antioxidant effects of the cell-permeable short-chain C2 ceramide in rat brain astrocytes. C2 ceramide inhibited hydrogen peroxide-induced reactive oxygen species generation and subsequent cell death in rat primary astrocytes. C2 ceramide increased the expression of phase II antioxidant enzymes, such as heme oxygenase-1 (HO-1), NAD(P)H:quinine oxidoreductase 1 (NQO1), and superoxide dismutase (SOD) that are under the control of Nrf2/ARE signaling pathways. Detailed mechanistic studies revealed that C2 ceramide increased the nuclear translocation and DNA binding of nuclear factor-E2-related factor 2 (Nrf2) and c-Jun to the antioxidant response element (ARE), and increased ARE-mediated transcriptional activity. Moreover, C2 ceramide increased the interaction between Nrf2 and c-Jun as shown by antibody co-immunoprecipitation assay. Further analysis of signaling pathways revealed that AMPK and MAP kinases are involved in HO-1 expression by modulating ARE-mediated transcriptional activity. Therefore, the upregulation of antioxidant enzymes by C2 ceramide may be a potential therapeutic modality for neurodegenerative diseases that are accompanied by oxidative stress.
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Affiliation(s)
- Ji-Sun Jung
- Department of Molecular Medicine and Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, South Korea
| | - Min-Ji Choi
- Department of Molecular Medicine and Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, South Korea
| | - Hyun-Myung Ko
- Department of Molecular Medicine and Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, South Korea
| | - Hee-Sun Kim
- Department of Molecular Medicine and Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, South Korea.
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Jernigan PL, Makley AT, Hoehn RS, Edwards MJ, Pritts TA. The role of sphingolipids in endothelial barrier function. Biol Chem 2016; 396:681-91. [PMID: 25867999 DOI: 10.1515/hsz-2014-0305] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Sphingolipids are a ubiquitous family of essential lipids with an increasingly understood role as biologically active mediators in numerous physiologic and pathologic processes. Two particular sphingolipid species, sphingosine-1-phosphate and ceramide, and their metabolites interact both directly and indirectly with endothelial cells to regulate vascular permeability. Sphingosine-1-phosphate generally augments endothelial integrity while ceramide tends to promote vascular leak, and a tight balance between the two is necessary to maintain normal physiologic function. The mechanisms by which sphingolipids regulate endothelial barrier function are complex and occur through multiple different pathways, and disruptions or imbalances in these pathways have been implicated in a number of specific disease processes. With improved understanding of sphingolipid biology, endothelial function, and the interactions between the two, several targets for therapeutic intervention have emerged and there is immense potential for further advancement in this field.
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Zhang Y, Pan Y, Bian Z, Chen P, Zhu S, Gu H, Guo L, Hu C. Ceramide Production Mediates Aldosterone-Induced Human Umbilical Vein Endothelial Cell (HUVEC) Damages. PLoS One 2016; 11:e0146944. [PMID: 26788916 PMCID: PMC4720365 DOI: 10.1371/journal.pone.0146944] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 12/23/2015] [Indexed: 01/09/2023] Open
Abstract
Here, we studied the underlying mechanism of aldosterone (Aldo)-induced vascular endothelial cell damages by focusing on ceramide. We confirmed that Aldo (at nmol/L) inhibited human umbilical vein endothelial cells (HUVEC) survival, and induced considerable cell apoptosis. We propose that ceramide (mainly C18) production might be responsible for Aldo-mediated damages in HUVECs. Sphingosine-1-phosphate (S1P), an anti-ceramide lipid, attenuated Aldo-induced ceramide production and following HUVEC damages. On the other hand, the glucosylceramide synthase (GCS) inhibitor PDMP or the ceramide (C6) potentiated Aldo-induced HUVEC apoptosis. Eplerenone, a mineralocorticoid receptor (MR) antagonist, almost completely blocked Aldo-induced C18 ceramide production and HUVEC damages. Molecularly, ceramide synthase 1 (CerS-1) is required for C18 ceramide production by Aldo. Knockdown of CerS-1 by targeted-shRNA inhibited Aldo-induced C18 ceramide production, and protected HUVECs from Aldo. Reversely, CerS-1 overexpression facilitated Aldo-induced C18 ceramide production, and potentiated HUVEC damages. Together, these results suggest that C18 ceramide production mediates Aldo-mediated HUVEC damages. MR and CerS-1 could be the two signaling molecule regulating C18 ceramide production by Aldo.
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Affiliation(s)
- Yumei Zhang
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Yu Pan
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Zhixiang Bian
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Peihua Chen
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Shijian Zhu
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Huiyi Gu
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Liping Guo
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
| | - Chun Hu
- Division of Nephrology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, 201999, China
- * E-mail:
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FragClust and TestClust, two informatics tools for chemical structure hierarchical clustering analysis applied to lipidomics. The example of Alzheimer's disease. Anal Bioanal Chem 2016; 408:2215-26. [DOI: 10.1007/s00216-015-9229-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/25/2015] [Accepted: 11/27/2015] [Indexed: 01/08/2023]
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Lin CF, Tsai CC, Huang WC, Wang YC, Tseng PC, Tsai TT, Chen CL. Glycogen Synthase Kinase-3β and Caspase-2 Mediate Ceramide- and Etoposide-Induced Apoptosis by Regulating the Lysosomal-Mitochondrial Axis. PLoS One 2016; 11:e0145460. [PMID: 26727221 PMCID: PMC4699703 DOI: 10.1371/journal.pone.0145460] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/03/2015] [Indexed: 11/18/2022] Open
Abstract
Glycogen synthase kinase-3β (GSK-3β) regulates the sequential activation of caspase-2 and caspase-8 before mitochondrial apoptosis. Here, we report the regulation of Mcl-1 destabilization and cathepsin D-regulated caspase-8 activation by GSK-3β and caspase-2. Treatment with either the ceramide analogue C2-ceramide or the topoisomerase II inhibitor etoposide sequentially induced lysosomal membrane permeabilization (LMP), the reduction of mitochondrial transmembrane potential, and apoptosis. Following LMP, cathepsin D translocated from lysosomes to the cytoplasm, whereas inhibiting cathepsin D blocked mitochondrial apoptosis. Furthermore, cathepsin D caused the activation of caspase-8 but not caspase-2. Inhibiting GSK-3β and caspase-2 blocked Mcl-1 destabilization, LMP, cathepsin D re-localization, caspase-8 activation, and mitochondrial apoptosis. Expression of Mcl-1 was localized to the lysosomes, and forced expression of Mcl-1 prevented apoptotic signaling via the lysosomal-mitochondrial pathway. These results demonstrate the importance of GSK-3β and caspase-2 in ceramide- and etoposide-induced apoptosis through mechanisms involving Mcl-1 destabilization and the lysosomal-mitochondrial axis.
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Affiliation(s)
- Chiou-Feng Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Cheng-Chieh Tsai
- Department of Nursing, Chung Hwa University of Medical Technology, Tainan, 717, Taiwan
| | - Wei-Ching Huang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Yu-Chih Wang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Po-Chun Tseng
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Tsung-Ting Tsai
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Chia-Ling Chen
- Translational Research Center, Taipei Medical University, Taipei, 110, Taiwan
- * E-mail:
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60
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Methods for Testing Immunological Factors. DRUG DISCOVERY AND EVALUATION: PHARMACOLOGICAL ASSAYS 2016. [PMCID: PMC7122208 DOI: 10.1007/978-3-319-05392-9_45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hypersensitivity reactions can be elicited by various factors: either immunologically induced, i.e., allergic reactions to natural or synthetic compounds mediated by IgE, or non-immunologically induced, i.e., activation of mediator release from cells through direct contact, without the induction of, or the mediation through immune responses. Mediators responsible for hypersensitivity reactions are released from mast cells. An important preformed mediator of allergic reactions found in these cells is histamine. Specific allergens or the calcium ionophore 48/80 induce release of histamine from mast cells. The histamine concentration can be determined with the o-phthalaldehyde reaction.
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61
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Yang L, Jin GH, Zhou JY. The Role of Ceramide in the Pathogenesis of Alcoholic Liver Disease. Alcohol Alcohol 2015; 51:251-7. [PMID: 26511776 DOI: 10.1093/alcalc/agv119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 09/22/2015] [Indexed: 02/06/2023] Open
Abstract
AIMS Ceramide is an important second messenger in the sphingomyelin signaling pathway. In this review, we will focus on the potential role of ceramide in the pathogenesis of alcoholic liver disease (ALD). METHODS We have summarized the relevant studies and reviews about the role of ceramide in ALD. In addition, we have discussed the role of acid sphingomyelinase and protein phosphatase 2A in ALD, which are associated with ceramide and hepatic steatosis. RESULTS Recent studies have proved that the immunoreactivity and content of ceramide were increased, both in experimental models of chronic alcohol-induced steatohepatitis and human livers with severe chronic alcohol-related liver disease. Consistent with that, the levels of protein phosphatase 2A and acid sphingomyelinase were increased. Of relevance, the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) was inhibited, which could block the fatty acid oxidation and promote its synthesis. CONCLUSIONS It was hypothesized that ethanol promoted ceramide accumulation and increased PP2A activity by activating ASMase, which may be an important mechanism in the inhibitory effect on AMPK phosphorylation and then contributed to the progression of steatosis. ASMase, a specific mechanism of ceramide generation, was proved to be a regulator of steatosis, fibrosis, lipotoxicity and endoplasmic reticulum stress.
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Affiliation(s)
- Liu Yang
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Guo-Hua Jin
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Jun-Ying Zhou
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
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Inhibition of sphingosine kinase 2 downregulates the expression of c-Myc and Mcl-1 and induces apoptosis in multiple myeloma. Blood 2015; 124:1915-25. [PMID: 25122609 DOI: 10.1182/blood-2014-03-559385] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Sphingolipid metabolism is being increasingly recognized as a key pathway in regulating cancer cell survival and proliferation. However, very little is known about its role in multiple myeloma (MM). We investigated the potential of targeting sphingosine kinase 2 (SK2) for the treatment of MM. We found that SK2 was overexpressed in MM cell lines and in primary human bone marrow (BM) CD1381 myeloma cells. Inhibition of SK2 by SK2- specific short hairpin RNA or ABC294640 (a SK2 specific inhibitor) effectively inhibited myeloma cell proliferation and induced caspase 3–mediated apoptosis. ABC294640 inhibited primary human CD1381 myeloma cells with the same efficacy as with MM cell lines. ABC294640 effectively induced apoptosis of myeloma cells, even in the presence of BM stromal cells. Furthermore, we found that ABC294640 downregulated the expression of pS6 and directed c-Myc and myeloid cell leukemia 1 (Mcl-1) for proteasome degradation. In addition, ABC294640 increased Noxa gene transcription and protein expression. ABC294640, per se, did not affect the expression of B-cell lymphoma 2 (Bcl-2), but acted synergistically with ABT-737 (a Bcl-2 inhibitor) in inducing myeloma cell death. ABC294640 suppressed myeloma tumor growth in vivo in mouse myeloma xenograft models. Our data demonstrated that SK2 provides a novel therapeutic target for the treatment of MM.This trial was registered at www.clinicaltrials.gov as #NCT01410981.
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63
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Hermann A, Sitdikova GF, Weiger TM. Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels. Biomolecules 2015; 5:1870-911. [PMID: 26287261 PMCID: PMC4598779 DOI: 10.3390/biom5031870] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 01/13/2023] Open
Abstract
All cells contain ion channels in their outer (plasma) and inner (organelle) membranes. Ion channels, similar to other proteins, are targets of oxidative impact, which modulates ion fluxes across membranes. Subsequently, these ion currents affect electrical excitability, such as action potential discharge (in neurons, muscle, and receptor cells), alteration of the membrane resting potential, synaptic transmission, hormone secretion, muscle contraction or coordination of the cell cycle. In this chapter we summarize effects of oxidative stress and redox mechanisms on some ion channels, in particular on maxi calcium-activated potassium (BK) channels which play an outstanding role in a plethora of physiological and pathophysiological functions in almost all cells and tissues. We first elaborate on some general features of ion channel structure and function and then summarize effects of oxidative alterations of ion channels and their functional consequences.
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Affiliation(s)
- Anton Hermann
- Department of Cell Biology, Division of Cellular and Molecular Neurobiology, University of Salzburg, Salzburg 5020, Austria.
| | - Guzel F Sitdikova
- Department of Physiology of Man and Animals, Kazan Federal University, Kazan 420008, Russia.
| | - Thomas M Weiger
- Department of Cell Biology, Division of Cellular and Molecular Neurobiology, University of Salzburg, Salzburg 5020, Austria.
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64
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Uchida Y, Kim YI, Park K. Signaling roles of ceramide and its metabolites in cutaneous antimicrobial defense. DERMATOL SIN 2015. [DOI: 10.1016/j.dsi.2015.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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65
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Xu W, Xu B, Yao Y, Yu X, Shen J. The novel HDAC inhibitor AR-42-induced anti-colon cancer cell activity is associated with ceramide production. Biochem Biophys Res Commun 2015; 463:545-50. [PMID: 26026677 DOI: 10.1016/j.bbrc.2015.05.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 05/25/2015] [Indexed: 01/22/2023]
Abstract
In the current study, we investigated the potential activity of AR-42, a novel histone deacetylase (HDAC) inhibitor, against colon cancer cells. Our in vitro results showed that AR-42 induced ceramide production, exerted potent anti-proliferative and pro-apoptotic activities in established (SW-620 and HCT-116 lines) and primary human colon cancer cells. Exogenously-added sphingosine 1-phosphate (S1P) suppressed AR-42-induced activity, yet a cell-permeable ceramide (C4) facilitated AR-42-induced cytotoxicity against colon cancer cells. In addition, AR-42-induced ceramide production and anti-colon cancer cell activity were inhibited by the ceramide synthase inhibitor fumonisin B1, but were exacerbated by PDMP, which is a ceramide glucosylation inhibitor. In vivo, oral administration of a single dose of AR-42 dramatically inhibited SW-620 xenograft growth in severe combined immunodeficient (SCID) mice, without inducing overt toxicities. Together, these results show that AR-42 dramatically inhibits colon cancer cell proliferation in vitro and in vivo, and ceramide production might be the key mechanism responsible for its actions.
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Affiliation(s)
- Weihong Xu
- Department of Clinical Laboratory, Tongren Hospital, Shanghai, China
| | - Bin Xu
- Department of Clinical Laboratory, Tongren Hospital, Shanghai, China
| | - Yiting Yao
- Department of Clinical Laboratory, Tongren Hospital, Shanghai, China
| | - Xiaoling Yu
- Department of Clinical Laboratory, Tongren Hospital, Shanghai, China
| | - Jie Shen
- Department of Administrative, Tongren Hospital, No. 786 Yuyuan Road, Changning District, Shanghai, China.
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66
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Wauquier F, Léotoing L, Philippe C, Spilmont M, Coxam V, Wittrant Y. Pros and cons of fatty acids in bone biology. Prog Lipid Res 2015; 58:121-45. [PMID: 25835096 DOI: 10.1016/j.plipres.2015.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/06/2015] [Accepted: 03/23/2015] [Indexed: 12/12/2022]
Abstract
Despite the growing interest in deciphering the causes and consequences of obesity-related disorders, the mechanisms linking fat intake to bone behaviour remain unclear. Since bone fractures are widely associated with increased morbidity and mortality, most notably in elderly and obese people, bone health has become a major social and economic issue. Consistently, public health system guidelines have encouraged low-fat diets in order to reduce associated complications. However, from a bone point of view, mechanisms linking fat intake to bone alteration remain quite controversial. Thus, after more than a decade of dedicated studies, this timely review offers a comprehensive overview of the relationships between bone and fatty acids. Using clinical evidences as a starting-point to more complex molecular elucidation, this work highlights the complexity of the system and reveals that bone alteration that cannot be solved simply by taking ω-3 pills. Fatty acid effects on bone metabolism can be both direct and indirect and require integrated investigations. Furthermore, even at the level of a single cell, one fatty acid is able to trigger several different independent pathways (receptors, metabolites…) which may all have a say in the final cellular metabolic response.
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Affiliation(s)
- Fabien Wauquier
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Laurent Léotoing
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Claire Philippe
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Mélanie Spilmont
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Véronique Coxam
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France
| | - Yohann Wittrant
- INRA, UMR 1019, UNH, CRNH Auvergne, F-63009 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; Equipe Alimentation, Squelette et Métabolismes, France.
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Bellini L, Campana M, Mahfouz R, Carlier A, Véret J, Magnan C, Hajduch E, Le Stunff H. Targeting sphingolipid metabolism in the treatment of obesity/type 2 diabetes. Expert Opin Ther Targets 2015; 19:1037-50. [PMID: 25814122 DOI: 10.1517/14728222.2015.1028359] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Obesity is a major factor that is linked to the development of type 2 diabetes (T2D). Excess circulating fatty acids (FAs), which characterize obesity, induce insulin resistance, steatosis, β cells dysfunction and apoptosis. These deleterious effects have been defined as lipotoxicity. AREAS COVERED FAs are metabolized to different lipid species, including ceramides which play a crucial role in lipotoxicity. The action of ceramides on tissues, such as muscle, liver, adipose tissue and pancreatic β cells, during the development of T2D will also be reviewed. In addition, the potential antagonist action of other sphingolipids, namely sphingoid base phosphates, on lipotoxicity in skeletal muscle and β cells will be addressed. EXPERT OPINION Ceramide is a critical mediator to the development of T2D linked to obesity. Targeting proteins involved in ceramide's deleterious action has not been possible due to their involvement in many other intracellular signaling pathways. A possible means of counteracting ceramide action would be to prevent the accumulation of the specific ceramide species involved in both insulin resistance and β-cell apoptosis/dysfunction. Another possibility would be to adjust the dynamic balance between ceramide and sphingoid base phosphate, both known to display opposing properties on the development of T2D-linked obesity.
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Affiliation(s)
- Lara Bellini
- Université PARIS-DIDEROT (7), Unité Biologie Fonctionnelle et Adaptative - UMR CNRS 8251, Équipe Régulation de la glycémie par le système nerveux central (REGLYS) , 4, rue Marie-Andrée Lagroua Weill-Halle, 75205 PARIS Cedex 13 , France +01 57 27 77 97 ; +01 57 27 77 96 ;
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Kumagai T, Kozakai Y, Ishino T, Yajima Y, Nakagawa Y, Imai H. Nrf2 up-regulates the induction of acidic sphingomyelinase by electrophiles. J Biochem 2015; 158:127-37. [PMID: 25762726 DOI: 10.1093/jb/mvv030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/01/2015] [Indexed: 11/13/2022] Open
Abstract
Acidic sphingomyelinase (ASMase) catalyses the generation of ceramide from sphingomyelin. Ceramide is a lipid mediator and is implicated in mediating and regulating various cellular processes including cell proliferation, differentiation, stress response and inflammation. We have previously reported that electrophiles including diethyl maleate (DEM), heavy metals and cigarette smoke extracts induced ASMase expression in human bladder carcinoma ECV-304 cells, but the mechanism of ASMase mRNA induction by electrophiles remains unknown. In this study, we clarified the involvement of NF-E2-related factor 2 (Nrf2) in the induction of ASMase mRNA by DEM. Promoter analysis using a series of deletion mutants of the human ASMase gene showed that ARE-like element1 located in a region between -200 and -160 bp upstream of the transcription start point is mainly a DEM-responsive element. Moreover, an electrophoretic mobility shift assay using ARE-like element1 revealed that Nrf2 is a candidate transcription factor that binds to ARE-like element1 in response to DEM. Finally, alteration of Nrf2 expression by overexpression and knockdown could regulate the induction of ASMase mRNA by DEM. This is the first evidence that supports the possibility that sphingolipid metabolism is affected via the induction of ASMase by the Nrf2 pathway.
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Affiliation(s)
- Takeshi Kumagai
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yosuke Kozakai
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Tomohiro Ishino
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuichi Yajima
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasuhito Nakagawa
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Hirotaka Imai
- Laboratory of Hygienic Chemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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69
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Cheng L, Chen YZ, Peng Y, Yi N, Gu XS, Jin Y, Bai XM. Ceramide production mediates cinobufotalin-induced growth inhibition and apoptosis in cultured hepatocellular carcinoma cells. Tumour Biol 2015; 36:5763-71. [PMID: 25724183 DOI: 10.1007/s13277-015-3245-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/10/2015] [Indexed: 12/21/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a highly aggressive and lethal neoplasm with poor prognosis. The aim of this study is to investigate the anticancer activity of cinobufotalin, a bufadienolide isolated from toad venom, in cultured HCC cells, and to study the underlying mechanisms. We found that cinobufotalin (at nmol/L) significantly inhibited HCC cell growth and survival while inducing considerable cell apoptosis. Further, cinobufotalin inhibited sphingosine kinase 1 (SphK1) activity and induced pro-apoptotic ceramide production. Ceramide synthase-1 small hairpin RNA (shRNA)-depletion inhibited cinobufotalin-induced ceramide production and HCC cell apoptosis. On the other hand, the glucosylceramide synthase (GCS) inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) facilitated cinobufotalin-induced ceramide production and cell apoptosis. SphK1 inhibitor II (SKI-II), similar to cinobufotalin, increased cellular ceramide level and promoted HCC cell apoptosis. Finally, we observed that cinobufotalin inactivated Akt-S6K1 signaling in HepG2 cells, which was again inhibited by ceramide synthase-1 shRNA-depletion. In conclusion, the results of this study suggest that cinobufotalin induces growth inhibition and apoptosis in cultured HCC cells through ceramide production. Cinobufotalin may be investigated as a novel anti-HCC agent.
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Affiliation(s)
- Long Cheng
- Department of Interventional Radiology, The Second Affiliated Hospital of Soochow University, Soochow University, Suzhou, 215001, China
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70
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Murray JM, Thompson AM, Vitsky A, Hawes M, Chuang WL, Pacheco J, Wilson S, McPherson JM, Thurberg BL, Karey KP, Andrews L. Nonclinical safety assessment of recombinant human acid sphingomyelinase (rhASM) for the treatment of acid sphingomyelinase deficiency:the utility of animal models of disease in the toxicological evaluation of potential therapeutics. Mol Genet Metab 2015; 114:217-25. [PMID: 25092414 DOI: 10.1016/j.ymgme.2014.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 11/28/2022]
Abstract
Recombinant human acid sphingomyelinase (rhASM) is being developed as an enzyme replacement therapy for patients with acid sphingomyelinase deficiency (Niemann-Pick disease types A and B), which causes sphingomyelin to accumulate in lysosomes. In the acid sphingomyelinase knock-out (ASMKO) mouse, intravenously administered rhASM reduced tissue sphingomyelin levels in a dose-dependent manner. When rhASM was administered to normal rats, mice, and dogs, no toxicity was observed up to a dose of 30mg/kg. However, high doses of rhASM≥10mg/kg administered to ASMKO mice resulted in unexpected toxicity characterized by cardiovascular shock, hepatic inflammation, adrenal hemorrhage, elevations in ceramide and cytokines (especially IL-6, G-CSF, and keratinocyte chemoattractant [KC]), and death. The toxicity could be completely prevented by the administration of several low doses (3mg/kg) of rhASM prior to single or repeated high doses (≥20mg/kg). These results suggest that the observed toxicity involves the rapid breakdown of large amounts of sphingomyelin into ceramide and/or other toxic downstream metabolites, which are known signaling molecules with cardiovascular and pro-inflammatory effects. Our results suggest that the nonclinical safety assessment of novel therapeutics should include the use of specific animal models of disease whenever feasible.
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Affiliation(s)
- James M Murray
- Department of Pharmacology and Toxicology, Genzyme Corporation, Framingham, MA 01701, USA.
| | - Anne Marie Thompson
- Department of Pharmacology and Toxicology, Genzyme Corporation, Framingham, MA 01701, USA
| | - Allison Vitsky
- Department of Pathology, Genzyme Corporation, Framingham, MA 01701, USA
| | - Michael Hawes
- Department of Pathology, Genzyme Corporation, Framingham, MA 01701, USA
| | - Wei-Lien Chuang
- Department of Biologics Structural and Functional Research, Genzyme Corporation, Framingham, MA 01701, USA
| | - Joshua Pacheco
- Department of Biologics Structural and Functional Research, Genzyme Corporation, Framingham, MA 01701, USA
| | - Stephen Wilson
- Charles River Laboratories, Preclinical Services, Reno, NV 89511, USA
| | - John M McPherson
- Department of Biologics Research and Development, Genzyme Corporation, Framingham, MA 01701, USA
| | - Beth L Thurberg
- Department of Pathology, Genzyme Corporation, Framingham, MA 01701, USA
| | - Kenneth P Karey
- Early Process Development, Genzyme Corporation, Framingham, MA 01701, USA
| | - Laura Andrews
- Department of Pharmacology and Toxicology, Genzyme Corporation, Framingham, MA 01701, USA
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71
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Yang L, Zheng LY, Tian Y, Zhang ZQ, Dong WL, Wang XF, Zhang XY, Cao C. C6 ceramide dramatically enhances docetaxel-induced growth inhibition and apoptosis in cultured breast cancer cells: a mechanism study. Exp Cell Res 2015; 332:47-59. [PMID: 25576381 DOI: 10.1016/j.yexcr.2014.12.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 12/14/2014] [Accepted: 12/26/2014] [Indexed: 01/26/2023]
Abstract
Here we reported that co-administration of docetaxel and a cell-permeable short-chain ceramide (C6) resulted in a striking increase in growth inhibition and apoptosis in primary and transformed breast cells (MCF-7 and MDA-231), which were associated with mitochondrial permeability transition pore (mPTP) opening, a significant reactive oxygen species (ROS) production and the pro-apoptotic AMP-Protein Kinase (AMPK) as well as c-Jun N-terminal kinases (JNK) activations. Contrarily, the mPTP blocker sanglifehrin A (SfA) or the ROS scavenger N-acetyl-l-cysteine (NAC) largely inhibited co-administration-induced cytotoxicity. Further, cyclosporin A (CsA), the inhibitor of cyclophilin-D (Cyp-D, the key mPTP component), as well as Cyp-D RNA silencing also suppressed breast cancer cell death by the co-treatment, while cells overexpressing Cyp-D showed hypersensitivity to docetaxel. Meanwhile, JNK and AMPK inhibition alleviated cell death induced by the co-administration in cultured breast cancer cells. Significantly, C6 ceramide plus docetaxel caused dramatic human epidermal growth factor receptor (HER)-1/-2 degradation and downstream Akt/Erk inhibition in HER-2 expressing MDA-231 cells. These in vitro findings provide confidence in support of further development of C6 ceramide as an adjunct of docetaxel for the treatment of the metastatic breast cancer.
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Affiliation(s)
- Lan Yang
- Department of Breast Surgery, the Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Li-Yun Zheng
- Department of Neurology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Ye Tian
- Department of Radiotherapy and Oncology, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Zhi-Qing Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215021, China
| | - Wan-Li Dong
- Department of Neurology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xu-Fen Wang
- Department of Breast Surgery, the Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
| | - Xiao-Ying Zhang
- Department of Cardiothoracic Surgery, the Third Affiliated Hospital of Soochow University, Changzhou, China.
| | - Cong Cao
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215021, China.
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Carroll B, Donaldson JC, Obeid L. Sphingolipids in the DNA damage response. Adv Biol Regul 2014; 58:38-52. [PMID: 25434743 DOI: 10.1016/j.jbior.2014.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 12/16/2022]
Abstract
Recently, sphingolipid metabolizing enzymes have emerged as important targets of many chemotherapeutics and DNA damaging agents and therefore play significant roles in mediating the physiological response of the cell to DNA damage. In this review we will highlight points of connection between the DNA damage response (DDR) and sphingolipid metabolism; specifically how certain sphingolipid enzymes are regulated in response to DNA damage and how the bioactive lipids produced by these enzymes affect cell fate.
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Affiliation(s)
- Brittany Carroll
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Jane Catalina Donaldson
- Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Lina Obeid
- Northport VA Medical Center, Northport, NY 11768, USA; Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794, USA.
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El-Dahshan A, Al-Gharabli SI, Radetzki S, Al-Tel TH, Kumar P, Rademann J. Flexible, polymer-supported synthesis of sphingosine derivatives provides ceramides with enhanced biological activity. Bioorg Med Chem 2014; 22:5506-12. [DOI: 10.1016/j.bmc.2014.07.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 11/26/2022]
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Zhou Y, Niu J, Li S, Hou H, Xu Y, Zhang W, Jiang Y. Radioprotective effects of valproic acid, a histone deacetylase inhibitor, in the rat brain. Biomed Rep 2014; 3:63-69. [PMID: 25469249 DOI: 10.3892/br.2014.367] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/27/2014] [Indexed: 01/08/2023] Open
Abstract
Radiotherapy is commonly used in the treatment of brain tumors but can cause significant damage to surrounding normal brain. The radioprotective effects of valproic acid (VPA) on normal tissue in the rat brain were evaluated following irradiation. Male Wistar rats were used in the present study and 48 rats were randomly divided into four groups consisting of 12 rats each. The whole-brain irradiation (WBI) was delivered by X-ray and the rats received the following treatment once a day for 5 days. The control group (sham-exposed group) received sham irradiation plus physiological saline. The VPA group received sham irradiation plus 150 mg VPA/kg. The X-ray group received WBI plus physiological saline. The combined group received WBI plus 150 mg/kg intraperitoneally VPA. A total of 6 months post-irradiation, the rats were sacrificed and the brains were harvested. Cell apoptosis in the cortex was determined by immunohistochemistry 24 h post-irradiation using an antibody for protein caspase-3. Transmission electron microscope (TEM) analyses were used to assess the effects of VPA on the radioprotection of rat normal brain cells 6 months post-irradiation. The weights of the animals in the TEM group measured over the two weeks after the first injection of VPA were also observed. Histological findings demonstrated that apoptosis occurred on the cortex 1 day after treatment, peaking in the X-ray group. The cells of the combined group showed a moderate caspase-3 staining compared to the X-ray group. There was a trend towards a lower body weight of the X-ray group following irradiation compared to either no-irradiation or rats of the combined group, although there was no significant difference in the average weight between the combined group and irradiated rats. Mild swelling of the capillary endothelial cells in the irregular lumen was observed in the combined group, whereas the X-ray group showed a severe structural disorder. In conclusion, VPA supplementation during radiotherapy may be beneficial for radioprotection following WBI by reducing normal brain cell injury.
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Affiliation(s)
- Yong Zhou
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Junjie Niu
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Shupeng Li
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Huaying Hou
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Ying Xu
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Wei Zhang
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Yuhua Jiang
- Cancer Centre, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
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75
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Kim HC, Al-Mahrouki A, Gorjizadeh A, Sadeghi-Naini A, Karshafian R, Czarnota GJ. Quantitative ultrasound characterization of tumor cell death: ultrasound-stimulated microbubbles for radiation enhancement. PLoS One 2014; 9:e102343. [PMID: 25051356 PMCID: PMC4106764 DOI: 10.1371/journal.pone.0102343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 06/17/2014] [Indexed: 12/15/2022] Open
Abstract
The aim of this study was to assess the efficacy of quantitative ultrasound imaging in characterizing cancer cell death caused by enhanced radiation treatments. This investigation focused on developing this ultrasound modality as an imaging-based non-invasive method that can be used to monitor therapeutic ultrasound and radiation effects. High-frequency (25 MHz) ultrasound was used to image tumor responses caused by ultrasound-stimulated microbubbles in combination with radiation. Human prostate xenografts grown in severe combined immunodeficiency (SCID) mice were treated using 8, 80, or 1000 µL/kg of microbubbles stimulated with ultrasound at 250, 570, or 750 kPa, and exposed to 0, 2, or 8 Gy of radiation. Tumors were imaged prior to treatment and 24 hours after treatment. Spectral analysis of images acquired from treated tumors revealed overall increases in ultrasound backscatter intensity and the spectral intercept parameter. The increase in backscatter intensity compared to the control ranged from 1.9±1.6 dB for the clinical imaging dose of microbubbles (8 µL/kg, 250 kPa, 2 Gy) to 7.0±4.1 dB for the most extreme treatment condition (1000 µL/kg, 750 kPa, 8 Gy). In parallel, in situ end-labelling (ISEL) staining, ceramide, and cyclophilin A staining demonstrated increases in cell death due to DNA fragmentation, ceramide-mediated apoptosis, and release of cyclophilin A as a result of cell membrane permeabilization, respectively. Quantitative ultrasound results indicated changes that paralleled increases in cell death observed from histology analyses supporting its use for non-invasive monitoring of cancer treatment outcomes.
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Affiliation(s)
- Hyunjung Christina Kim
- Department of Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Azza Al-Mahrouki
- Department of Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Alborz Gorjizadeh
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Ali Sadeghi-Naini
- Department of Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Raffi Karshafian
- Department of Physics, Ryerson University, Toronto, Ontario, Canada
| | - Gregory J. Czarnota
- Department of Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physics, Ryerson University, Toronto, Ontario, Canada
- * E-mail:
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In vitro palmitate treatment of myotubes from postmenopausal women leads to ceramide accumulation, inflammation and affected insulin signaling. PLoS One 2014; 9:e101555. [PMID: 25000528 PMCID: PMC4084812 DOI: 10.1371/journal.pone.0101555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/07/2014] [Indexed: 11/19/2022] Open
Abstract
Menopause is associated with an increased incidence of insulin resistance and metabolic diseases. In a chronic palmitate treatment model, we investigated the role of skeletal muscle fatty acid exposure in relation to the metabolic deterioration observed with menopause. Human skeletal muscle satellite cells were isolated from premenopausal (n = 6) and postmenopausal (n = 5) women. In an in vitro model, the myotubes were treated with palmitate (300 µM) for one-, two- or three days during differentiation. Effects on lipid accumulation, inflammation and insulin signaling were studied. Palmitate treatment led to a 108% (CI 95%: 50%; 267%) increase in intramyocellular ceramide in the myotubes from the postmenopausal women (post-myotubes) compared with a 26% (CI 95%: -57%; 96%) increase in myotubes from the premenopausal women (pre-myotubes), (p<0.05). Furthermore, post-myotubes had a 22% (CI 95%: 4%; 34%) increase in pJNK (p = 0.04) and a 114% (CI 95%: 50%; 177%) increase in Hsp70 protein expression (p = 0.03) after three days of palmitate treatment, compared with pre-myotubes, in which no increase in either pJNK (-12% (CI 95: -26%; 2%)) or Hsp70 (7% (CI 95: -78%; 91%)) was detected. Furthermore, post-myotubes showed a blunted insulin stimulated phosphorylation of AS160 in response to chronic palmitate treatment compared with pre-myotubes (p = 0.02). The increased intramyocellular ceramide content in the post-myotubes was associated with a significantly higher mRNA expression of Serine Palmitoyltransferase1 (SPT1) after one day of palmitate treatment (p = 0.03) in post-myotubes compared with pre-myotubes. Our findings indicate that post-myotubes are more prone to develop lipid accumulation and defective insulin signaling following chronic saturated fatty acid exposure as compared to pre-myotubes.
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Li Y, Li S, Qin X, Hou W, Dong H, Yao L, Xiong L. The pleiotropic roles of sphingolipid signaling in autophagy. Cell Death Dis 2014; 5:e1245. [PMID: 24853423 PMCID: PMC4047895 DOI: 10.1038/cddis.2014.215] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 04/10/2014] [Accepted: 04/15/2014] [Indexed: 12/11/2022]
Abstract
The autophagic process involves encompassing damaged proteins and organelles within double- or multi-membraned structures and delivering these molecules to the lytic compartments of vacuoles. Sphingolipids (SLs), which are ubiquitous membrane lipids in eukaryotes, participate in the generation of various membrane structures, including rafts, caveolae, and cytosolic vesicles. SLs are a complex family of molecules that have a growing number of members, including ceramide, sphingosine-1-phosphate, and dihydroceramide, which have been associated with the essential cellular process of autophagy. This review highlights recent studies focusing on the regulation and function of SL-associated autophagy and its role in cell fate, diseases, and therapeutic interventions.
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Affiliation(s)
- Y Li
- 1] The State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an 710032, China [2] Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - S Li
- 1] The State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an 710032, China [2] Department of Oral Biology, Stomatology School, The Fourth Military Medical University, Xi'an 710032, China
| | - X Qin
- Department of Chemistry, Pharmacy School, The Fourth Military Medical University, Xi'an 710032, China
| | - W Hou
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - H Dong
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - L Yao
- The State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an 710032, China
| | - L Xiong
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
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Bleasel JM, Wong JH, Halliday GM, Kim WS. Lipid dysfunction and pathogenesis of multiple system atrophy. Acta Neuropathol Commun 2014; 2:15. [PMID: 24502382 PMCID: PMC3922275 DOI: 10.1186/2051-5960-2-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/03/2014] [Indexed: 12/24/2022] Open
Abstract
Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by the accumulation of α-synuclein protein in the cytoplasm of oligodendrocytes, the myelin-producing support cells of the central nervous system (CNS). The brain is the most lipid-rich organ in the body and disordered metabolism of various lipid constituents is increasingly recognized as an important factor in the pathogenesis of several neurodegenerative diseases. α-Synuclein is a 17 kDa protein with a close association to lipid membranes and biosynthetic processes in the CNS, yet its precise function is a matter of speculation, particularly in oligodendrocytes. α-Synuclein aggregation in neurons is a well-characterized feature of Parkinson’s disease and dementia with Lewy bodies. Epidemiological evidence and in vitro studies of α-synuclein molecular dynamics suggest that disordered lipid homeostasis may play a role in the pathogenesis of α-synuclein aggregation. However, MSA is distinct from other α-synucleinopathies in a number of respects, not least the disparate cellular focus of α-synuclein pathology. The recent identification of causal mutations and polymorphisms in COQ2, a gene encoding a biosynthetic enzyme for the production of the lipid-soluble electron carrier coenzyme Q10 (ubiquinone), puts membrane transporters as central to MSA pathogenesis, although how such transporters are involved in the early myelin degeneration observed in MSA remains unclear. The purpose of this review is to bring together available evidence to explore the potential role of membrane transporters and lipid dyshomeostasis in the pathogenesis of α-synuclein aggregation in MSA. We hypothesize that dysregulation of the specialized lipid metabolism involved in myelin synthesis and maintenance by oligodendrocytes underlies the unique neuropathology of MSA.
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79
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Stafford JH, Hao G, Best AM, Sun X, Thorpe PE. Highly specific PET imaging of prostate tumors in mice with an iodine-124-labeled antibody fragment that targets phosphatidylserine. PLoS One 2013; 8:e84864. [PMID: 24367699 PMCID: PMC3868598 DOI: 10.1371/journal.pone.0084864] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/20/2013] [Indexed: 02/07/2023] Open
Abstract
Phosphatidylserine (PS) is an attractive target for imaging agents that identify tumors and assess their response to therapy. PS is absent from the surface of most cell types, but becomes exposed on tumor cells and tumor vasculature in response to oxidative stresses in the tumor microenvironment and increases in response to therapy. To image exposed PS, we used a fully human PS-targeting antibody fragment, PGN635 F(ab’)2, that binds to complexes of PS and β2-glycoprotein I. PGN635 F(ab’)2 was labeled with the positron-emitting isotope iodine-124 (124I) and the resulting probe was injected into nude mice bearing subcutaneous or orthotopic human PC3 prostate tumors. Biodistribution studies showed that 124I-PGN635 F(ab’)2 localized with remarkable specificity to the tumors with little uptake in other organs, including the liver and kidneys. Clear delineation of the tumors was achieved by PET 48 hours after injection. Radiation of the tumors with 15 Gy or systemic treatment of the mice with 10 mg/kg docetaxel increased localization in the tumors. Tumor-to-normal (T/N) ratios were inversely correlated with tumor growth measured over 28 days. These data indicate that 124I-PGN635 F(ab’)2 is a promising new imaging agent for predicting tumor response to therapy.
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Affiliation(s)
- Jason H. Stafford
- Department of Pharmacology, The Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- *
| | - Guiyang Hao
- Department of Radiology, The Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Anne M. Best
- Department of Pharmacology, The Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Xiankai Sun
- Department of Radiology, The Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Philip E. Thorpe
- Department of Pharmacology, The Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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80
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Ishii T, Warabi E, Siow RCM, Mann GE. Sequestosome1/p62: a regulator of redox-sensitive voltage-activated potassium channels, arterial remodeling, inflammation, and neurite outgrowth. Free Radic Biol Med 2013; 65:102-116. [PMID: 23792273 DOI: 10.1016/j.freeradbiomed.2013.06.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/06/2013] [Accepted: 06/07/2013] [Indexed: 12/14/2022]
Abstract
Sequestosome1/p62 (SQSTM1) is an oxidative stress-inducible protein regulated by the redox-sensitive transcription factor Nrf2. It is not an antioxidant but known as a multifunctional regulator of cell signaling with an ability to modulate targeted or selective degradation of proteins through autophagy. SQSTM1 implements these functions through physical interactions with different types of proteins including atypical PKCs, nonreceptor-type tyrosine kinase p56(Lck) (Lck), polyubiquitin, and autophagosomal factor LC3. One of the notable physiological functions of SQSTM1 is the regulation of redox-sensitive voltage-gated potassium (Kv) channels which are composed of α and β subunits: (Kvα)4 (Kvβ)4. Previous studies have established that SQSTM1 scaffolds PKCζ, enhancing phosphorylation of Kvβ which induces inhibition of pulmonary arterial Kv1.5 channels under acute hypoxia. Recent studies reveal that Lck indirectly interacts with Kv1.3 α subunits and plays a key role in acute hypoxia-induced Kv1.3 channel inhibition in T lymphocytes. Kv1.3 channels provide a signaling platform to modulate the migration and proliferation of arterial smooth muscle cells and activation of T lymphocytes, and hence have been recognized as a therapeutic target for treatment of restenosis and autoimmune diseases. In this review, we focus on the functional interactions of SQSTM1 with Kv channels through two key partners aPKCs and Lck. Furthermore, we provide molecular insights into the functions of SQSTM1 in suppression of proliferation of arterial smooth muscle cells and neointimal hyperplasia following carotid artery ligation, in T lymphocyte differentiation and activation, and in NGF-induced neurite outgrowth in PC12 cells.
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Affiliation(s)
- Tetsuro Ishii
- School of Medicine, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Eiji Warabi
- School of Medicine, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8575, Japan
| | - Richard C M Siow
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, School of Medicine, King's College London, London SE1 9NH, UK
| | - Giovanni E Mann
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, School of Medicine, King's College London, London SE1 9NH, UK
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81
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Dasgupta S, Kong J, Bieberich E. Phytoceramide in vertebrate tissues: one step chromatography separation for molecular characterization of ceramide species. PLoS One 2013; 8:e80841. [PMID: 24312247 PMCID: PMC3843679 DOI: 10.1371/journal.pone.0080841] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/15/2013] [Indexed: 11/19/2022] Open
Abstract
Ceramide is a precursor for complex sphingolipids in vertebrates, while plants contain phytoceramide. By using a novel chromatography purification method we show that phytoceramide comprises a significant proportion of animal sphingolipids. Total ceramide including phytoceramide from mouse tissue (brain, heart, liver) lipid extracts and cell culture (mouse primary astrocytes, human oligodendroglioma cells) was eluted as a single homogenous fraction, and then analyzed by thin layer chromatography, and further characterized by gas chromatography-mass spectrometry (GC-MS). We detected a unique band that migrated between non-hydroxy fatty acyl ceramide and hydroxy fatty acyl ceramide, and identified it as phytoceramide. Using RT-PCR, we confirmed that mouse tissues expressed desaturase 2, an enzyme that has been reported to generate phytoceramide from dihydroceramide. Previously, only trace amounts of phytoceramide were reported in vertebrate intestine, kidney, and skin. While its function is still elusive, this is the first report of phytoceramide characterization in glial cells and vertebrate brain, heart, and liver.
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Affiliation(s)
- Somsankar Dasgupta
- Program in Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia, United States of America
| | - Jina Kong
- Program in Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia, United States of America
| | - Erhard Bieberich
- Program in Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia, United States of America
- * E-mail:
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82
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Pacheco A, Azevedo F, Rego A, Santos J, Chaves SR, Côrte-Real M, Sousa MJ. C2-phytoceramide perturbs lipid rafts and cell integrity in Saccharomyces cerevisiae in a sterol-dependent manner. PLoS One 2013; 8:e74240. [PMID: 24040213 PMCID: PMC3770674 DOI: 10.1371/journal.pone.0074240] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 07/31/2013] [Indexed: 11/19/2022] Open
Abstract
Specific ceramides are key regulators of cell fate, and extensive studies aimed to develop therapies based on ceramide-induced cell death. However, the mechanisms regulating ceramide cytotoxicity are not yet fully elucidated. Since ceramides also regulate growth and stress responses in yeast, we studied how different exogenous ceramides affect yeast cells. C2-phytoceramide, a soluble form of phytoceramides, the yeast counterparts of mammalian ceramides, greatly reduced clonogenic survival, particularly in the G2/M phase, but did not induce autophagy nor increase apoptotic markers. Rather, the loss of clonogenic survival was associated with PI positive staining, disorganization of lipid rafts and cell wall weakening. Sensitivity to C2-phytoceramide was exacerbated in mutants lacking Hog1p, the MAP kinase homolog of human p38 kinase. Decreasing sterol membrane content reduced sensitivity to C2-phytoceramide, suggesting sterols are the targets of this compound. This study identified a new function of C2-phytoceramide through disorganization of lipid rafts and induction of a necrotic cell death under hypo-osmotic conditions. Since lipid rafts are important in mammalian cell signaling and adhesion, our findings further support pursuing the exploitation of yeast to understand the basis of synthetic ceramides' cytotoxicity to provide novel strategies for therapeutic intervention in cancer and other diseases.
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Affiliation(s)
- Andreia Pacheco
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal
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83
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Pinto SN, Fernandes F, Fedorov A, Futerman AH, Silva LC, Prieto M. A combined fluorescence spectroscopy, confocal and 2-photon microscopy approach to re-evaluate the properties of sphingolipid domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2099-110. [DOI: 10.1016/j.bbamem.2013.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/10/2013] [Accepted: 05/13/2013] [Indexed: 12/29/2022]
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84
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Electronegative LDL: a circulating modified LDL with a role in inflammation. Mediators Inflamm 2013; 2013:181324. [PMID: 24062611 PMCID: PMC3766570 DOI: 10.1155/2013/181324] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/19/2013] [Indexed: 12/13/2022] Open
Abstract
Electronegative low density lipoprotein (LDL(−)) is a minor modified fraction of LDL found in blood. It comprises a heterogeneous population of LDL particles modified by various mechanisms sharing as a common feature increased electronegativity. Modification by oxidation is one of these mechanisms. LDL(−) has inflammatory properties similar to those of oxidized LDL (oxLDL), such as inflammatory cytokine release in leukocytes and endothelial cells. However, in contrast with oxLDL, LDL(−) also has some anti-inflammatory effects on cultured cells. The inflammatory and anti-inflammatory properties ascribed to LDL(−) suggest that it could have a dual biological effect.
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85
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Elevation in sphingomyelin synthase activity is associated with increases in amyloid-beta peptide generation. PLoS One 2013; 8:e74016. [PMID: 23977395 PMCID: PMC3748018 DOI: 10.1371/journal.pone.0074016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/25/2013] [Indexed: 11/19/2022] Open
Abstract
A pathological hallmark of Alzheimer’s disease (AD) is the presence of amyloid-beta peptide (Aβ) plaques in the brain. Aβ is derived from a sequential proteolysis of the transmenbrane amyloid precursor protein (APP), a process which is dependent on the distribution of lipids present in the plasma membrane. Sphingomyelin is a major membrane lipid, however its role in APP processing is unclear. Here, we assessed the expression of sphingomyelin synthase (SGMS1; the gene responsible for sphingomyelin synthesis) in human brain and found that it was significantly elevated in the hippocampus of AD brains, but not in the cerebellum. Secondly, we assessed the impact of altering SGMS activity on Aβ generation. Inhibition of SGMS activity significantly reduced the level of Aβ in a dose- and time dependent manner. The decrease in Aβ level occurred without changes in APP expression or cell viability. These results when put together indicate that SGMS activity impacts on APP processing to produce Aβ and it could be a contributing factor in Aβ pathology associated with AD.
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86
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Huang X, Withers BR, Dickson RC. Sphingolipids and lifespan regulation. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:657-64. [PMID: 23954556 DOI: 10.1016/j.bbalip.2013.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/01/2013] [Accepted: 08/06/2013] [Indexed: 02/08/2023]
Abstract
Diseases including cancer, type 2 diabetes, cardiovascular and immune dysfunction and neurodegeneration become more prevalent as we age, and combined with the increase in average human lifespan, place an ever increasing burden on the health care system. In this chapter we focus on finding ways of modulating sphingolipids to prevent the development of age-associated diseases or delay their onset, both of which could improve health in elderly, fragile people. Reducing the incidence of or delaying the onset of diseases of aging has blossomed in the past decade because of advances in understanding signal transduction pathways and cellular processes, especially in model organisms, that are largely conserved in most eukaryotes and that can be modulated to reduce signs of aging and increase health span. In model organisms such interventions must also increase lifespan to be considered significant, but this is not a requirement for use in humans. The most encouraging interventions in model organisms involve lowering the concentration of one or more sphingolipids so as to reduce the activity of key signaling pathways, one of the most promising being the Target of Rapamycin Complex 1 (TORC1) protein kinase pathway. Other potential ways in which modulating sphingolipids may contribute to improving the health profile of the elderly is by reducing oxidative stresses, inflammatory responses and growth factor signaling. Lastly, perhaps the most interesting way to modulate sphingolipids and promote longevity is by lowering the activity of serine palmitoyltransferase, the first enzyme in the de novo sphingolipid biosynthesis pathway. Available data in yeasts and rodents are encouraging and as we gain insights into molecular mechanisms the strategies for improving human health by modulating sphingolipids will become more apparent. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Xinhe Huang
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA
| | - Bradley R Withers
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA
| | - Robert C Dickson
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA.
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87
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Robciuc A, Hyötyläinen T, Jauhiainen M, Holopainen JM. Ceramides in the pathophysiology of the anterior segment of the eye. Curr Eye Res 2013; 38:1006-16. [PMID: 23885886 DOI: 10.3109/02713683.2013.810273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
PURPOSE Sphingolipid (SL) research reached a peak in the past years. Yet this positive trend was not evident for eye research as the relative number of studies centered on SLs is decreasing. Our aim is to encourage the inclusion of SL metabolites in studies of ocular pathophysiology by summarizing recent findings and current awareness concerning ceramides in the anterior segment of the eye. METHODS Review of literature relating to ceramides as bioactive lipids and the extent to which their particular nature was investigated in ocular pathophysiology. RESULTS Ceramides are rare but indispensable lipids that influence cellular responses through their effects on membrane biophysical properties or direct interaction with target proteins. Their biological significance is increased by variability and adaptability as there are tens of enzymes designed to modulate their function. The eye offers a set of unique environments where ceramides or other SLs have not been extensively studied. Not surprisingly, ceramides were associated with apoptosis in the metabolically active tissues, while little is known about its effects on the biophysical properties of the tears or lens lipids. More so, there are still aspects of the ocular homeostasis control where SLs contribution has not been investigated to date (e.g. pathogen aggression). CONCLUSIONS Ceramides and SL metabolism still receive increasing attention and have proven to be a significant metabolite in many research fields (e.g. cancer, stress response and inflammation) and there are yet many questions that they will aid answer. With the present work, we seek to increase awareness of these lipids also in eye research and to highlight their importance as common regulators of various diseases.
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Affiliation(s)
- Alexandra Robciuc
- Department of Ophthalmology, University of Helsinki, Helsinki Eye Lab, Helsinki, Finland
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88
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Chen CL, Lin CF, Wan SW, Wei LS, Chen MC, Yeh TM, Liu HS, Anderson R, Lin YS. Anti–Dengue Virus Nonstructural Protein 1 Antibodies Cause NO-Mediated Endothelial Cell Apoptosis via Ceramide-Regulated Glycogen Synthase Kinase-3β and NF-κB Activation. THE JOURNAL OF IMMUNOLOGY 2013; 191:1744-52. [DOI: 10.4049/jimmunol.1201976] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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89
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Trounce IA, Crouch PJ, Carey KT, McKenzie M. Modulation of ceramide-induced cell death and superoxide production by mitochondrial DNA-encoded respiratory chain defects in Rattus xenocybrid mouse cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:817-25. [DOI: 10.1016/j.bbabio.2013.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/26/2013] [Accepted: 03/28/2013] [Indexed: 10/27/2022]
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90
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Abstract
The role of sphingolipids as bioactive signaling molecules that can regulate cell fate decisions puts them at center stage for cancer treatment and prevention. While ceramide and sphingosine have been established as antigrowth molecules, sphingosine-1-phosphate (S1P) offers a progrowth message to cells. The enzymes responsible for maintaining the balance between these "stop" or "go" signals are the sphingosine kinases (SK), SK1 and SK2. While the relative contribution of SK2 is still being elucidated and may involve an intranuclear role, a substantial amount of evidence suggests that regulation of sphingolipid levels by SK1 is an important component of carcinogenesis. Here, we review the literature regarding the role of SK1 as an oncogene that can function to enhance cancer cell viability and promote tumor growth and metastasis; highlighting the importance of developing specific SK1 inhibitors to supplement current cancer therapies.
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Affiliation(s)
- Linda A Heffernan-Stroud
- Molecular and Cellular Biology and Pathobiology Program, Medical University of South Carolina, Charleston, SC, USA
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91
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Abstract
Members of the ABCA (ATP-binding cassette subfamily A) family are characterized by their ability to transport lipids across cellular membranes and regulate lipid homoeostasis in the brain and peripheral tissues. ABCA8 is a little-known member of this subfamily that was originally cloned from human brain libraries and has no known function. In an effort to elucidate the role of ABCA8 in the brain we first undertook a comprehensive analysis of its expression in the human brain. ABCA8 was differentially expressed in multiple regions of adult human brains with significantly higher expression in oligodendrocyte-enriched white matter regions compared with grey matter cortical regions. We then assessed the impact of ABCA8 on sphingomyelin production in oligodendrocyte and showed that ABCA8 was able to significantly stimulate both sphingomyelin synthase 1 expression and sphingomyelin production. Furthermore, ABCA8 expression in the prefrontal cortex across the human life span correlated strongly with age-associated myelination, and the myelinating gene p25α was significantly up-regulated with ABCA8. The present study represents the first extensive expression and functional study of ABCA8 in the human brain and the results strongly suggest that ABCA8 regulates lipid metabolism in oligodendrocytes and potentially plays a role in myelin formation and maintenance.
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92
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McArdle MA, Finucane OM, Connaughton RM, McMorrow AM, Roche HM. Mechanisms of obesity-induced inflammation and insulin resistance: insights into the emerging role of nutritional strategies. Front Endocrinol (Lausanne) 2013; 4:52. [PMID: 23675368 PMCID: PMC3650620 DOI: 10.3389/fendo.2013.00052] [Citation(s) in RCA: 339] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 04/22/2013] [Indexed: 12/11/2022] Open
Abstract
Obesity and associated chronic inflammation initiate a state of insulin resistance (IR). The secretion of chemoattractants such as MCP-1 and MIF and of cytokines IL-6, TNF-α, and IL-1β, draw immune cells including dendritic cells, T cells, and macrophages into adipose tissue (AT). Dysfunctional AT lipid metabolism leads to increased circulating free fatty acids, initiating inflammatory signaling cascades in the population of infiltrating cells. A feedback loop of pro-inflammatory cytokines exacerbates this pathological state, driving further immune cell infiltration and cytokine secretion and disrupts the insulin signaling cascade. Disruption of normal AT function is causative of defects in hepatic and skeletal muscle glucose homeostasis, resulting in systemic IR and ultimately the development of type 2 diabetes. Pharmaceutical strategies that target the inflammatory milieu may have some potential; however there are a number of safety concerns surrounding such pharmaceutical approaches. Nutritional anti-inflammatory interventions could offer a more suitable long-term alternative; whilst they may be less potent than some pharmaceutical anti-inflammatory agents, this may be advantageous for long-term therapy. This review will investigate obese AT biology, initiation of the inflammatory, and insulin resistant environment; and the mechanisms through which dietary anti-inflammatory components/functional nutrients may be beneficial.
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Affiliation(s)
- Maeve A. McArdle
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Orla M. Finucane
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Ruth M. Connaughton
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Aoibheann M. McMorrow
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
| | - Helen M. Roche
- Nutrigenomics Research Group, UCD Conway Institute, School of Public Health, Physiotherapy and Population Science, University College DublinDublin, Republic of Ireland
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93
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Reich A, Mędrek K. Effects of narrow band UVB (311 nm) irradiation on epidermal cells. Int J Mol Sci 2013; 14:8456-66. [PMID: 23594996 PMCID: PMC3645754 DOI: 10.3390/ijms14048456] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/09/2013] [Accepted: 04/09/2013] [Indexed: 01/02/2023] Open
Abstract
Ultraviolet radiation (UVR) is known to be one of the most important environmental hazards acting on the skin. It was revealed that chronic exposure to UVR accelerates skin aging, induces immunosuppression and may lead to the development of skin cancers. On the other hand, UVR has been shown to be effective in the treatment of numerous skin diseases and thus, various phototherapy modalities have been developed to date. Narrow-band ultraviolet B (NB-UVB) emitting a light with a peak around 311 nm has been demonstrated to be effective in the treatment of various skin disorders; currently it is one of the most commonly used phototherapy devices. Despite NB-UVB has been developed more than 30 years ago, the exact mechanism of its therapeutic action remains poorly understood. To date, most of NB-UVB effects were attributed to its influence on immune cells; however, nearly 90% of NB-UVB irradiation is absorbed by epidermis and keratinocytes seem to be important players in mediating NB-UVB biological activity. Here, we have reviewed the current data about the influence of NB-UVB on epidermal cells, with a special emphasis on cell proliferation and death.
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Affiliation(s)
- Adam Reich
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Chałubińskiego 1, Wrocław 50-368, Poland.
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94
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Wargo MJ. Choline catabolism to glycine betaine contributes to Pseudomonas aeruginosa survival during murine lung infection. PLoS One 2013; 8:e56850. [PMID: 23457628 PMCID: PMC3572970 DOI: 10.1371/journal.pone.0056850] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/15/2013] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa can acquire and metabolize a variety of molecules including choline, an abundant host-derived molecule. In P. aeruginosa, choline is oxidized to glycine betaine which can be used as an osmoprotectant, a sole source of carbon and nitrogen, and as an inducer of the virulence factor, hemolytic phospholipase C (PlcH) via the transcriptional regulator GbdR. The primary objective was to determine the contribution of choline conversion to glycine betaine to P. aeruginosa survival during mouse lung infection. A secondary objective was to gain insight into the relative contributions of the different roles of glycine betaine to P. aeruginosa survival during infection. Using a model of acute murine pneumonia, we determined that deletion of the choline oxidase system (encoded by betBA) decreased P. aeruginosa survival in the mouse lung. Deletion of the glycine betaine demethylase genes (gbcA-B), required for glycine betaine catabolism, did not impact P. aeruginosa survival in the lung. Thus, the defect of the betBA mutant was not due to a requirement for glycine betaine catabolism or dependence on a downstream metabolite. Deletion of betBA decreased the abundance of plcH transcript during infection, which suggested a role for PlcH in the betBA survival defect. To test the contribution of plcH to the betBA mutant phenotype a betBAplcHR double deletion mutant was generated. The betBA and betBAplcHR double mutant had a small but significant survival defect compared to the plcHR single mutant, suggesting that regulation of plcH expression is not the only role for glycine betaine during infection. The conclusion was that choline acquisition and its oxidation to glycine betaine contribute to P. aeruginosa survival in the mouse lung. While defective plcH induction can explain a portion of the betBA mutant phenotype, the exact mechanisms driving the betBA mutant survival defect remain unknown.
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Affiliation(s)
- Matthew J Wargo
- Department of Microbiology and Molecular Genetics and The Vermont Lung Center, University of Vermont College of Medicine, Burlington, Vermont, United States of America.
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Tikhonenko M, Lydic TA, Opreanu M, Li Calzi S, Bozack S, McSorley KM, Sochacki AL, Faber MS, Hazra S, Duclos S, Guberski D, Reid GE, Grant MB, Busik JV. N-3 polyunsaturated Fatty acids prevent diabetic retinopathy by inhibition of retinal vascular damage and enhanced endothelial progenitor cell reparative function. PLoS One 2013; 8:e55177. [PMID: 23383097 PMCID: PMC3558503 DOI: 10.1371/journal.pone.0055177] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/19/2012] [Indexed: 11/23/2022] Open
Abstract
Objective The vasodegenerative phase of diabetic retinopathy is characterized by not only retinal vascular degeneration but also inadequate vascular repair due to compromised bone marrow derived endothelial progenitor cells (EPCs). We propose that n-3 polyunsaturated fatty acid (PUFA) deficiency in diabetes results in activation of the central enzyme of sphingolipid metabolism, acid sphingomyelinase (ASM) and that ASM represents a molecular metabolic link connecting the initial damage in the retina and the dysfunction of EPCs. Research Design and Methods Type 2 diabetic rats on control or docosahexaenoic acid (DHA)-rich diet were studied. The number of acellular capillaries in the retinas was assessed by trypsin digest. mRNA levels of interleukin (IL)-1β, IL-6, intracellular adhesion molecule (ICAM)-1 in the retinas from diabetic animals were compared to controls and ASM protein was assessed by western analysis. EPCs were isolated from blood and bone marrow and their numbers and ability to form colonies in vitro, ASM activity and lipid profiles were determined. Results DHA-rich diet prevented diabetes-induced increase in the number of retinal acellular capillaries and significantly enhanced the life span of type 2 diabetic animals. DHA-rich diet blocked upregulation of ASM and other inflammatory markers in diabetic retina and prevented the increase in ASM activity in EPCs, normalized the numbers of circulating EPCs and improved EPC colony formation. Conclusions In a type 2 diabetes animal model, DHA-rich diet fully prevented retinal vascular pathology through inhibition of ASM in both retina and EPCs, leading to a concomitant suppression of retinal inflammation and correction of EPC number and function.
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Affiliation(s)
- Maria Tikhonenko
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Todd A. Lydic
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Madalina Opreanu
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Sergio Li Calzi
- Department of Pharmacology and Therapeutics University of Florida, Gainesville, Florida, United States of America
| | - Svetlana Bozack
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Kelly M. McSorley
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Andrew L. Sochacki
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Matthew S. Faber
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Sugata Hazra
- Department of Pharmacology and Therapeutics University of Florida, Gainesville, Florida, United States of America
| | - Shane Duclos
- Biomedical Research Models, Inc., Worcester, Massachusetts, United States of America
| | - Dennis Guberski
- Biomedical Research Models, Inc., Worcester, Massachusetts, United States of America
| | - Gavin E. Reid
- Department of Chemistry and Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
| | - Maria B. Grant
- Department of Pharmacology and Therapeutics University of Florida, Gainesville, Florida, United States of America
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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96
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The Induction of Cytokine Release in Monocytes by Electronegative Low-Density Lipoprotein (LDL) Is Related to Its Higher Ceramide Content than Native LDL. Int J Mol Sci 2013; 14:2601-16. [PMID: 23358250 PMCID: PMC3588005 DOI: 10.3390/ijms14022601] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/05/2013] [Accepted: 01/16/2013] [Indexed: 12/21/2022] Open
Abstract
Electronegative low-density lipoprotein (LDL(−)) is a minor modified LDL subfraction that is present in blood. LDL(−) promotes inflammation and is associated with the development of atherosclerosis. We previously reported that the increase of cytokine release promoted by this lipoprotein subfraction in monocytes is counteracted by high-density lipoprotein (HDL). HDL also inhibits a phospholipase C-like activity (PLC-like) intrinsic to LDL(−). The aim of this work was to assess whether the inhibition of the PLC-like activity by HDL could decrease the content of ceramide (CER) and diacylglycerol (DAG) generated in LDL(−). This knowledge would allow us to establish a relationship between these compounds and the inflammatory activity of LDL(−). LDL(−) incubated at 37 °C for 20 h increased its PLC-like activity and, subsequently, the amount of CER and DAG. We found that incubating LDL(−) with HDL decreased both products in LDL(−). Native LDL was modified by lipolysis with PLC or by incubation with CER-enriched or DAG-enriched liposomes. The increase of CER in native LDL significantly increased cytokine release, whereas the enrichment in DAG did not show these inflammatory properties. These data point to CER, a resultant product of the PLC-like activity, as a major determinant of the inflammatory activity induced by LDL(−) in monocytes.
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97
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Abstract
There are several well-established mechanisms involved in radiation-induced cell death in mammalian cell systems. The p53-mediated apoptotic pathway is the most widely recognized mechanism (Lowe et al. Nature 362:847-849, 1993), although apoptosis has long been considered a less relevant mechanism of radiation-induced cell death (Steel, Acta Oncol 40:968-975, 2001; Brown and Wouters, Cancer Res 59:1391-1399, 1999; Olive and Durand, Int J Radiat Biol 71:695-707, 1997). We and others have recently focused instead on the emerging links between radiation, apoptosis, and ceramide and showed that ceramide is a sphingolipid-derived second messenger capable of initiating apoptotic cascades in response to various stress stimuli, including radiation.Ceramide, the backbone of all sphingolipids, is synthesized by a family of ceramide synthases (CerS), each using acyl-CoAs of defined chain length for N-acylation of the sphingoid long-chain base. Six mammalian CerS homologs have been cloned that demonstrated high selectivity towards acyl-CoAs (Lahiri et al. FEBS Lett 581:5289-5294, 2007), and more recently, it was shown that their activity can be modulated by dimer formation (Mesicek et al. Cell Signal 22:1300-1307, 2010; Laviad et al. J Biol Chem 283:5677-5684, 2008).This de novo ceramide synthesis has been observed in irradiated cells through a pathway normally suppressed by ataxia telangiectasia-mutated (ATM) protein, a key component of the cellular response to DNA double-strand breaks (Liao et al. J Biol Chem 274:17908-17917, 1999). ATM is not the sole factor known to affect apoptotic potential by modulating CerS activity. Recent work has also implicated protein kinase Cα (PKCα) as a potential CerS activator (Truman et al. Cancer Biol Ther 8:54-63, 2009).In this review, we summarize involvement of CerS in sphingolipid-mediated apoptosis in irradiated human prostate cancer cells and discuss future directions in this field.
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Affiliation(s)
- Carla Hajj
- Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
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98
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Accumulated bending energy elicits neutral sphingomyelinase activity in human red blood cells. Biophys J 2012; 102:2077-85. [PMID: 22824271 DOI: 10.1016/j.bpj.2012.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 02/01/2012] [Accepted: 03/12/2012] [Indexed: 02/02/2023] Open
Abstract
We propose that accumulated membrane bending energy elicits a neutral sphingomyelinase (SMase) activity in human erythrocytes. Membrane bending was achieved by osmotic or chemical processes, and SMase activity was assessed by quantitative thin-layer chromatography, high-performance liquid chromatography, and electrospray ionization-mass spectrometry. The activity induced by hypotonic stress in erythrocyte membranes had the pH dependence, ion dependence, and inhibitor sensitivity of mammalian neutral SMases. The activity caused a decrease in SM contents, with a minimum at 6 min after onset of the hypotonic conditions, and then the SM contents were recovered. We also elicited SMase activity by adding lysophosphatidylcholine externally or by generating it with phospholipase A(2). The same effect was observed upon addition of chlorpromazine or sodium deoxycholate at concentrations below the critical micellar concentration, and even under hypertonic conditions. A unifying factor of the various agents that elicit this SMase activity is the accumulated membrane bending energy. Both hypo-and hypertonic conditions impose an increased curvature, whereas the addition of surfactants or phospholipase A(2) activation increases the outer monolayer area, thus leading to an increased bending energy. The fact that this latent SMase activity is tightly coupled to the membrane bending properties suggests that it may be related to the general phenomenon of stress-induced ceramide synthesis and apoptosis.
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99
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Ren X, Xu J, Cooper JP, Kang MH, Erdreich-Epstein A. c-Abl is an upstream regulator of acid sphingomyelinase in apoptosis induced by inhibition of integrins αvβ3 and αvβ5. PLoS One 2012; 7:e42291. [PMID: 22879933 PMCID: PMC3411766 DOI: 10.1371/journal.pone.0042291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/05/2012] [Indexed: 12/17/2022] Open
Abstract
Inhibition of integrins αvβ3/αvβ5 by the cyclic function-blocking peptide, RGDfV (Arg-Gly-Asp-Phe-Val) can induce apoptosis in both normal cells and tumor cells. We show that RGDfV induced apoptosis in ECV-304 carcinoma cells, increased activity and mRNA expression of acid sphingomyelinase (ASM), and increased ceramides C16, C18∶0, C24∶0 and C24∶1 while decreasing the corresponding sphingomyelins. siRNA to ASM decreased RGDfV-induced apoptosis as measured by TUNEL, PARP cleavage, mitochondrial depolarization, and caspase-3 and caspase-8 activities, as well as by annexinV in a 3D collagen model. These findings indicate a causal role for ASM in RGDfV-induced apoptosis in ECV-304. We have shown that c-Abl, a non-receptor tyrosine kinase, also mediates RGDfV-induced apoptosis. However, c-Abl, has not been previously linked to ASM in any system. Here we show that STI-571 (imatinib, inhibitor of c-Abl) inhibited RGDfV-induced ASM activity. Furthermore, STI-571 and c-Abl-siRNA both inhibited RGDfV-induced increase in ASM mRNA, but ASM-siRNA did not affect c-Abl phosphorylation or expression, supporting that c-Abl regulates the RGDfV-induced increase in ASM expression. These studies implicate ASM as a mediator of apoptosis induced by inhibition of integrins αvβ3/αvβ5, and for the first time place c-Abl as an upstream regulator of ASM expression and activity.
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Affiliation(s)
- Xiuhai Ren
- Division of Hematology-Oncology, Department of Pediatrics, Keck School of Medicine, University of Southern California and the Saban Research Institute of Children's Hospital Los Angeles, Los Angeles, California, United States of America
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100
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Kolliputi N, Galam L, Parthasarathy PT, Tipparaju SM, Lockey RF. NALP-3 inflammasome silencing attenuates ceramide-induced transepithelial permeability. J Cell Physiol 2012; 227:3310-6. [PMID: 22169929 DOI: 10.1002/jcp.24026] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The hallmark of acute lung injury (ALI) is the influx of proinflammatory cytokines into lung tissue and alveolar permeability that ultimately leads to pulmonary edema. However, the mechanisms involved in inflammatory cytokine production and alveolar permeability are unclear. Recent studies suggest that excessive production of ceramide has clinical relevance as a mediator of pulmonary edema and ALI. Our earlier studies indicate that the activation of inflammasome promotes the processing and secretion of proinflammatory cytokines and causes alveolar permeability in ALI. However, the role of ceramide in inflammasome activation and the underlying mechanism in relation to alveolar permeability is not known. We hypothesized that ceramide activates the inflammasome and causes inflammatory cytokine production and alveolar epithelial permeability. To test this hypothesis, we analyzed the lung ceramide levels during hyperoxic ALI in mice. The effect of ceramide on activation of inflammasome and production of inflammatory cytokine was assessed in primary mouse alveolar macrophages and THP-1 cells. Alveolar transepithelial permeability was determined in alveolar epithelial type-II cells (AT-II) and THP-1 co-cultures. Our results reveal that ceramide causes inflammasome activation, induction of caspase-1, IL-1β cleavage, and release of proinflammatory cytokines. In addition, ceramide further induces alveolar epithelial permeability. Short-hairpin RNA silencing of inflammasome components abrogated ceramide-induced secretion of proinflammatory cytokines in vitro. Inflammasome silencing abolishes ceramide-induced alveolar epithelial permeability in AT-II. Collectively, our results demonstrate for the first time that ceramide-induced secretion of proinflammatory cytokines and alveolar epithelial permeability occurs though inflammasome activation.
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Affiliation(s)
- Narasaiah Kolliputi
- Division of Allergy and Immunology, Department of Internal Medicine, College of Medicine, University of South Florida, Tampa, Florida 33612, USA.
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