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Ge J, Koutarapu S, Jha D, Dulewicz M, Zetterberg H, Blennow K, Hanrieder J. Tetramodal Chemical Imaging Delineates the Lipid-Amyloid Peptide Interplay at Single Plaques in Transgenic Alzheimer's Disease Models. Anal Chem 2023; 95:4692-4702. [PMID: 36856542 PMCID: PMC10018455 DOI: 10.1021/acs.analchem.2c05302] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/16/2023] [Indexed: 03/02/2023]
Abstract
Beta-amyloid (Aβ) plaque pathology is one of the most prominent histopathological feature of Alzheimer's disease (AD). The exact pathogenic mechanisms linking Aβ to AD pathogenesis remain however not fully understood. Recent advances in amyloid-targeting pharmacotherapies highlight the critical relevance of Aβ aggregation for understanding the molecular basis of AD pathogenesis. We developed a novel, integrated, tetramodal chemical imaging paradigm for acquisition of trimodal mass spectrometry imaging (MSI) and interlaced fluorescent microscopy from a single tissue section. We used this approach to comprehensively investigate lipid-Aβ correlates at single plaques in two different mouse models of AD (tgAPPSwe and tgAPPArcSwe) with varying degrees of intrinsic properties affecting amyloid aggregation. Integration of the multimodal imaging data and multivariate data analysis identified characteristic patterns of plaque-associated lipid- and peptide localizations across both mouse models. Correlative fluorescence microscopy using structure-sensitive amyloid probes identified intra-plaque structure-specific lipid- and Aβ patterns, including Aβ 1-40 and Aβ 1-42 along with gangliosides (GM), phosphoinositols (PI), conjugated ceramides (CerP and PE-Cer), and lysophospholipids (LPC, LPA, and LPI). Single plaque correlation analysis across all modalities further revealed how these distinct lipid species were associated with Aβ peptide deposition across plaque heterogeneity, indicating different roles for those lipids in plaque growth and amyloid fibrillation, respectively. Here, conjugated ceramide species correlated with Aβ core formation indicating their involvement in initial plaque seeding or amyloid maturation. In contrast, LPI and PI were solely correlated with general plaque growth. In addition, GM1 and LPC correlated with continuous Aβ deposition and maturation. The results highlight the potential of this comprehensive multimodal imaging approach and implement distinct lipids in amyloidogenic proteinopathy.
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Affiliation(s)
- Junyue Ge
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
| | - Srinivas Koutarapu
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
| | - Durga Jha
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
| | - Maciej Dulewicz
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
| | - Henrik Zetterberg
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
- Clinical
Neurochemistry Laboratory, Sahlgrenska University
Hospital, Mölndal
Hospital, House V3, SE-431 80 Mölndal, Sweden
- Department
of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
- UK
Dementia Research Institute at University College London, Queen Square, London WC1N 3BG, United Kingdom
- Hong
Kong Center for Neurodegenerative Diseases, Hong Kong 1512-1518, China
- Wisconsin
Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, University
of Wisconsin-Madison, Madison, Wisconsin 53726, United States
| | - Kaj Blennow
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
- Clinical
Neurochemistry Laboratory, Sahlgrenska University
Hospital, Mölndal
Hospital, House V3, SE-431 80 Mölndal, Sweden
| | - Jörg Hanrieder
- Department
of Psychiatry and Neurochemistry, Sahlgrenska
Academy at the University of Gothenburg, Mölndal Hospital, House V3, SE-431 80 Mölndal, Sweden
- Clinical
Neurochemistry Laboratory, Sahlgrenska University
Hospital, Mölndal
Hospital, House V3, SE-431 80 Mölndal, Sweden
- Department
of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
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Pan J, Zhou L, Zhang C, Xu Q, Sun Y. Targeting protein phosphatases for the treatment of inflammation-related diseases: From signaling to therapy. Signal Transduct Target Ther 2022; 7:177. [PMID: 35665742 PMCID: PMC9166240 DOI: 10.1038/s41392-022-01038-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/28/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Inflammation is the common pathological basis of autoimmune diseases, metabolic diseases, malignant tumors, and other major chronic diseases. Inflammation plays an important role in tissue homeostasis. On one hand, inflammation can sense changes in the tissue environment, induce imbalance of tissue homeostasis, and cause tissue damage. On the other hand, inflammation can also initiate tissue damage repair and maintain normal tissue function by resolving injury and restoring homeostasis. These opposing functions emphasize the significance of accurate regulation of inflammatory homeostasis to ameliorate inflammation-related diseases. Potential mechanisms involve protein phosphorylation modifications by kinases and phosphatases, which have a crucial role in inflammatory homeostasis. The mechanisms by which many kinases resolve inflammation have been well reviewed, whereas a systematic summary of the functions of protein phosphatases in regulating inflammatory homeostasis is lacking. The molecular knowledge of protein phosphatases, and especially the unique biochemical traits of each family member, will be of critical importance for developing drugs that target phosphatases. Here, we provide a comprehensive summary of the structure, the "double-edged sword" function, and the extensive signaling pathways of all protein phosphatases in inflammation-related diseases, as well as their potential inhibitors or activators that can be used in therapeutic interventions in preclinical or clinical trials. We provide an integrated perspective on the current understanding of all the protein phosphatases associated with inflammation-related diseases, with the aim of facilitating the development of drugs that target protein phosphatases for the treatment of inflammation-related diseases.
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Affiliation(s)
- Jie Pan
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Lisha Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Chenyang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Qiang Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Yang Sun
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China.
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Cottrill KA, Giacalone VD, Margaroli C, Bridges RJ, Koval M, Tirouvanziam R, McCarty NA. Mechanistic analysis and significance of sphingomyelinase-mediated decreases in transepithelial CFTR currents in nHBEs. Physiol Rep 2021; 9:e15023. [PMID: 34514718 PMCID: PMC8436056 DOI: 10.14814/phy2.15023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/02/2021] [Indexed: 12/15/2022] Open
Abstract
Loss of function of the cystic fibrosis transmembrane conductance regulator (CFTR) causes cystic fibrosis (CF). In the lungs, this manifests as immune cell infiltration and bacterial infections, leading to tissue destruction. Previous work has determined that acute bacterial sphingomyelinase (SMase) decreases CFTR function in bronchial epithelial cells from individuals without CF (nHBEs) and with CF (cfHBEs, homozygous ΔF508-CFTR mutation). This study focuses on exploring the mechanisms underlying this effect. SMase increased the abundance of dihydroceramides, a result mimicked by blockade of ceramidase enzyme using ceranib-1, which also decreased CFTR function. The SMase-mediated inhibitory mechanism did not involve the reduction of cellular CFTR abundance or removal of CFTR from the apical surface, nor did it involve the activation of 5' adenosine monophosphate-activated protein kinase. In order to determine the pathological relevance of these sphingolipid imbalances, we evaluated the sphingolipid profiles of cfHBEs and cfHNEs (nasal) as compared to non-CF controls. Sphingomyelins, ceramides, and dihydroceramides were largely increased in CF cells. Correction of ΔF508-CFTR trafficking with VX445 + VX661 decreased some sphingomyelins and all ceramides, but exacerbated increases in dihydroceramides. Additional treatment with the CFTR potentiator VX770 did not affect these changes, suggesting rescue of misfolded CFTR was sufficient. We furthermore determined that cfHBEs express more acid-SMase protein than nHBEs. Lastly, we determined that airway-like neutrophils, which are increased in the CF lung, secrete acid-SMase. Identifying the mechanism of SMase-mediated inhibition of CFTR will be important, given the imbalance of sphingolipids in CF cells and the secretion of acid-SMase from cell types relevant to CF.
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Affiliation(s)
- Kirsten A. Cottrill
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Vincent D. Giacalone
- Immunology and Molecular Pathogenesis PhD ProgramEmory UniversityAtlantaGeorgiaUSA
| | - Camilla Margaroli
- Department of MedicineDivision of PulmonaryAllergy & Critical Care MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
- Program in Protease/Matrix BiologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Robert J. Bridges
- Department of Physiology and BiophysicsCenter for Genetic DiseasesChicago Medical SchoolNorth ChicagoIllinoisUSA
| | - Michael Koval
- Department of MedicineDivision of Pulmonary, Allergy, Critical Care and Sleep Medicine and Department of Cell BiologyEmory UniversityAtlantaGeorgiaUSA
| | - Rabindra Tirouvanziam
- Department of Pediatrics and Children’s Healthcare of AtlantaCenter for Cystic Fibrosis and Airways Disease ResearchEmory University School of MedicineAtlantaGeorgiaUSA
| | - Nael A. McCarty
- Molecular and Systems Pharmacology PhD ProgramEmory UniversityAtlantaGeorgiaUSA
- Department of Pediatrics and Children’s Healthcare of AtlantaCenter for Cystic Fibrosis and Airways Disease ResearchEmory University School of MedicineAtlantaGeorgiaUSA
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Wang G, Bieberich E. Sphingolipids in neurodegeneration (with focus on ceramide and S1P). Adv Biol Regul 2018; 70:51-64. [PMID: 30287225 PMCID: PMC6251739 DOI: 10.1016/j.jbior.2018.09.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/20/2018] [Accepted: 09/21/2018] [Indexed: 04/14/2023]
Abstract
For many decades, research on sphingolipids associated with neurodegenerative disease focused on alterations in glycosphingolipids, particularly glycosylceramides (cerebrosides), sulfatides, and gangliosides. This seemed quite natural since many of these glycolipids are constituents of myelin and accumulated in lipid storage diseases (sphingolipidoses) resulting from enzyme deficiencies in glycolipid metabolism. With the advent of recognizing ceramide and its derivative, sphingosine-1-phosphate (S1P), as key players in lipid cell signaling and regulation of cell death and survival, research focus shifted toward these two sphingolipids. Ceramide and S1P are invoked in a plethora of cell biological processes participating in neurodegeneration such as ER stress, autophagy, dysregulation of protein and lipid transport, exosome secretion and neurotoxic protein spreading, neuroinflammation, and mitochondrial dysfunction. Hence, it is timely to discuss various functions of ceramide and S1P in neurodegenerative disease and to define sphingolipid metabolism and cell signaling pathways as potential targets for therapy.
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Affiliation(s)
- Guanghu Wang
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky, Lexington, KY, USA.
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5
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Bieberich E. Sphingolipids and lipid rafts: Novel concepts and methods of analysis. Chem Phys Lipids 2018; 216:114-131. [PMID: 30194926 PMCID: PMC6196108 DOI: 10.1016/j.chemphyslip.2018.08.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/20/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022]
Abstract
About twenty years ago, the functional lipid raft model of the plasma membrane was published. It took into account decades of research showing that cellular membranes are not just homogenous mixtures of lipids and proteins. Lateral anisotropy leads to assembly of membrane domains with specific lipid and protein composition regulating vesicular traffic, cell polarity, and cell signaling pathways in a plethora of biological processes. However, what appeared to be a clearly defined entity of clustered raft lipids and proteins became increasingly fluid over the years, and many of the fundamental questions about biogenesis and structure of lipid rafts remained unanswered. Experimental obstacles in visualizing lipids and their interactions hampered progress in understanding just how big rafts are, where and when they are formed, and with which proteins raft lipids interact. In recent years, we have begun to answer some of these questions and sphingolipids may take center stage in re-defining the meaning and functional significance of lipid rafts. In addition to the archetypical cholesterol-sphingomyelin raft with liquid ordered (Lo) phase and the liquid-disordered (Ld) non-raft regions of cellular membranes, a third type of microdomains termed ceramide-rich platforms (CRPs) with gel-like structure has been identified. CRPs are "ceramide rafts" that may offer some fresh view on the membrane mesostructure and answer several critical questions for our understanding of lipid rafts.
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Affiliation(s)
- Erhard Bieberich
- Department of Physiology at the University of Kentucky, Lexington, KY, United States.
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6
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Therapeutic targeting of PP2A. Int J Biochem Cell Biol 2017; 96:182-193. [PMID: 29107183 DOI: 10.1016/j.biocel.2017.10.008] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022]
Abstract
Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase that regulates many cellular processes. Given the central role of PP2A in regulating diverse biological functions and its dysregulation in many diseases, including cancer, PP2A directed therapeutics have become of great interest. The main approaches leveraged thus far can be categorized as follows: 1) inhibiting endogenous inhibitors of PP2A, 2) targeted disruption of post translational modifications on PP2A subunits, or 3) direct targeting of PP2A. Additional insight into the structural, molecular, and biological framework driving the efficacy of these therapeutic strategies will provide a foundation for the refinement and development of novel and clinically tractable PP2A targeted therapies.
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7
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8
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Salminen A, Kaarniranta K, Kauppinen A. Age-related changes in AMPK activation: Role for AMPK phosphatases and inhibitory phosphorylation by upstream signaling pathways. Ageing Res Rev 2016; 28:15-26. [PMID: 27060201 DOI: 10.1016/j.arr.2016.04.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/18/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
AMP-activated protein kinase (AMPK) is a fundamental regulator of energy metabolism, stress resistance, and cellular proteostasis. AMPK signaling controls an integrated signaling network which is involved in the regulation of healthspan and lifespan e.g. via FoxO, mTOR/ULK1, CRCT-1/CREB, and SIRT1 signaling pathways. Several studies have demonstrated that the activation capacity of AMPK signaling declines with aging, which impairs the maintenance of efficient cellular homeostasis and enhances the aging process. However, it seems that the aging process affects AMPK activation in a context-dependent manner since occasionally, it can also augment AMPK activation, possibly attributable to the type of insult and tissue homeostasis. Three protein phosphatases, PP1, PP2A, and PP2C, inhibit AMPK activation by dephosphorylating the Thr172 residue of AMPKα, required for AMPK activation. In addition, several upstream signaling pathways can phosphorylate Ser/Thr residues in the β/γ interaction domain of the AMPKα subunit that subsequently blocks the activation of AMPK. These inhibitory pathways include the insulin/AKT, cyclic AMP/PKA, and RAS/MEK/ERK pathways. We will examine the evidence whether the efficiency of AMPK responsiveness declines during the aging process. Next, we will review the mechanisms involved in curtailing the activation of AMPK. Finally, we will elucidate the potential age-related changes in the inhibitory regulation of AMPK signaling that might be a part of the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
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Xu K, Wang L, Feng W, Feng Y, Shu HK. Phosphatidylinositol-3 kinase-dependent translational regulation of Id1 involves the PPM1G phosphatase. Oncogene 2016; 35:5807-5816. [PMID: 27065332 PMCID: PMC5064830 DOI: 10.1038/onc.2016.115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/04/2016] [Accepted: 01/22/2016] [Indexed: 12/30/2022]
Abstract
Id1 is a helix-loop-helix transcriptional modulator that increases the aggressiveness of malignant glial neoplasms. Since most glioblastomas (GBMs) show increased phosphatidylinositol-3 kinase (PI-3K) signaling, we sought to determine whether this pathway regulates Id1 expression. Higher basal Id1 expression correlates with dysregulated PI-3K signaling in multiple established GBM cell lines. Further characterization of PI-3K-dependent Id1 regulation reveals that chemical or genetic inhibition of PI-3K signaling reduces Id1 protein but not mRNA expression. Overall, PI-3K signaling appears to enhance Id1 translation with no significant effect on its stability. PI-3K signaling is known to regulate protein translation through mTORC1-dependent phosphorylation of 4E-BP1, which reduces its association with and inhibition of the translation initiation factor eIF4E. Interestingly, while inhibition of PI-3K and AKT lowers 4E-BP1 phosphorylation and expression of Id1 in all cases, inhibition of TORC1 with rapamycin does not consistently have a similar effect suggesting an alternative mechanism for PI-3K-dependent regulation of Id1 translation. We now identify a potential role for the serine-threonine phosphatase PPM1G in translational regulation of Id1 protein expression. PPM1G knockdown by siRNA increase both 4E-BP1 phosphorylation and Id1 expression and PPM1G and 4E-BP1 co-associates in GBM cells. Furthermore, PPM1G is a phosphoprotein and this phosphorylation appears to be regulated by PI-3K activity. Finally, PI-3K inhibition increases PPM1G activity when assessed by an in vitro phosphatase assay. Our findings provide the first evidence that the PI-3K/AKT signaling pathway modulates PPM1G activity resulting in a shift in the balance between hyper- and hypo-phosphorylated 4E-BP1 and translational regulation of Id1 expression.
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Affiliation(s)
- K Xu
- Department of Radiation Oncology and the Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - L Wang
- Department of Radiation Oncology and the Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - W Feng
- Department of Pharmacology, Emory University, Atlanta, GA, USA
| | - Y Feng
- Department of Pharmacology, Emory University, Atlanta, GA, USA
| | - H-Kg Shu
- Department of Radiation Oncology and the Winship Cancer Institute, Emory University, Atlanta, GA, USA
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Abstract
Studies over the past two decades have identified ceramide as a multifunctional central molecule in the sphingolipid biosynthetic pathway. Given its diverse tumor suppressive activities, molecular understanding of ceramide action will produce fundamental insights into processes that limit tumorigenesis and may identify key molecular targets for therapeutic intervention. Ceramide can be activated by a diverse array of stresses such as heat shock, genotoxic damage, oxidative stress and anticancer drugs. Ceramide triggers a variety of tumor suppressive and anti-proliferative cellular programs such as apoptosis, autophagy, senescence, and necroptosis by activating or repressing key effector molecules. Defects in ceramide generation and metabolism in cancer contribute to tumor cell survival and resistance to chemotherapy. The potent and versatile anticancer activity profile of ceramide has motivated drug development efforts to (re-)activate ceramide in established tumors. This review focuses on our current understanding of the tumor suppressive functions of ceramide and highlights the potential downstream targets of ceramide which are involved in its tumor suppressive action.
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Xie LJ, Chen QF, Chen MX, Yu LJ, Huang L, Chen L, Wang FZ, Xia FN, Zhu TR, Wu JX, Yin J, Liao B, Shi J, Zhang JH, Aharoni A, Yao N, Shu W, Xiao S. Unsaturation of very-long-chain ceramides protects plant from hypoxia-induced damages by modulating ethylene signaling in Arabidopsis. PLoS Genet 2015; 11:e1005143. [PMID: 25822663 PMCID: PMC4379176 DOI: 10.1371/journal.pgen.1005143] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 03/12/2015] [Indexed: 01/16/2023] Open
Abstract
Lipid remodeling is crucial for hypoxic tolerance in animals, whilst little is known about the hypoxia-induced lipid dynamics in plants. Here we performed a mass spectrometry-based analysis to survey the lipid profiles of Arabidopsis rosettes under various hypoxic conditions. We observed that hypoxia caused a significant increase in total amounts of phosphatidylserine, phosphatidic acid and oxidized lipids, but a decrease in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Particularly, significant gains in the polyunsaturated species of PC, PE and phosphatidylinositol, and losses in their saturated and mono-unsaturated species were evident during hypoxia. Moreover, hypoxia led to a remarkable elevation of ceramides and hydroxyceramides. Disruption of ceramide synthases LOH1, LOH2 and LOH3 enhanced plant sensitivity to dark submergence, but displayed more resistance to submergence under light than wild type. Consistently, levels of unsaturated very-long-chain (VLC) ceramide species (22:1, 24:1 and 26:1) predominantly declined in the loh1, loh2 and loh3 mutants under dark submergence. In contrast, significant reduction of VLC ceramides in the loh1-1 loh3-1 knockdown double mutant and lacking of VLC unsaturated ceramides in the ads2 mutants impaired plant tolerance to both dark and light submergences. Evidence that C24:1-ceramide interacted with recombinant CTR1 protein and inhibited its kinase activity in vitro, enhanced ER-to-nucleus translocation of EIN2-GFP and stabilization of EIN3-GFP in vivo, suggests a role of ceramides in modulating CTR1-mediated ethylene signaling. The dark submergence-sensitive phenotypes of loh mutants were rescued by a ctr1-1 mutation. Thus, our findings demonstrate that unsaturation of VLC ceramides is a protective strategy for hypoxic tolerance in Arabidopsis.
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Affiliation(s)
- Li-Juan Xie
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qin-Fang Chen
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Mo-Xian Chen
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Lu-Jun Yu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Li Huang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Liang Chen
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Feng-Zhu Wang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Fan-Nv Xia
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Tian-Ren Zhu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian Yin
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Bin Liao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianxin Shi
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jian-Hua Zhang
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Asaph Aharoni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Nan Yao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wensheng Shu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shi Xiao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Pondugula SR, Flannery PC, Apte U, Babu JR, Geetha T, Rege SD, Chen T, Abbott KL. Mg2+/Mn2+-dependent phosphatase 1A is involved in regulating pregnane X receptor-mediated cytochrome p450 3A4 gene expression. Drug Metab Dispos 2015; 43:385-91. [PMID: 25561723 PMCID: PMC11024896 DOI: 10.1124/dmd.114.062083] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/05/2015] [Indexed: 04/20/2024] Open
Abstract
Variations in the expression of human pregnane X receptor (hPXR)-mediated cytochrome p450 3A4 (CYP3A4) in liver can alter therapeutic response to a variety of drugs and may lead to potential adverse drug interactions. We sought to determine whether Mg(2+)/Mn(2+)-dependent phosphatase 1A (PPM1A) regulates hPXR-mediated CYP3A4 expression. PPM1A was found to be coimmunoprecipitated with hPXR. Genetic or pharmacologic activation of PPM1A led to a significant increase in hPXR transactivation of CYP3A4 promoter activity. In contrast, knockdown of endogenous PPM1A not only attenuated hPXR transactivation, but also increased proliferation of HepG2 human liver carcinoma cells, suggesting that PPM1A expression levels regulate hPXR, and that PPM1A expression is regulated in a proliferation-dependent manner. Indeed, PPM1A expression and hPXR transactivation were found to be significantly reduced in subconfluent HepG2 cells compared with confluent HepG2 cells, suggesting that both PPM1A expression and hPXR-mediated CYP3A4 expression may be downregulated in proliferating livers. Elevated PPM1A levels led to attenuation of hPXR inhibition by tumor necrosis factor-α and cyclin-dependent kinase-2, which are known to be upregulated and essential during liver regeneration. In mouse regenerating livers, similar to subconfluent HepG2 cells, expression of both PPM1A and the mouse PXR target gene cyp3a11 was found to be downregulated. Our results show that PPM1A can positively regulate PXR activity by counteracting PXR inhibitory signaling pathways that play a major role in liver regeneration. These results implicate a novel role for PPM1A in regulating hPXR-mediated CYP3A4 expression in hepatocytes and may explain a mechanism for CYP3A repression in regenerating livers.
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Affiliation(s)
- Satyanarayana R Pondugula
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Patrick C Flannery
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Udayan Apte
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Jeganathan Ramesh Babu
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Thangiah Geetha
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Shraddha D Rege
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Taosheng Chen
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
| | - Kodye L Abbott
- Department of Anatomy, Physiology, and Pharmacology (S.R.P., P.C.F., K.L.A.) and Department of Nutrition, Dietetics, and Hospitality Management (J.R.B., S.D.R.), Auburn University, Auburn, Alabama; Department of Chemistry (T.G.), Auburn University at Montgomery, Montgomery, Alabama; Department of Chemical Biology and Therapeutics (T.C.), St. Jude Children's Research Hospital, Memphis, Tennessee; and Department of Pharmacology, Toxicology, and Therapeutics (U.A.), University of Kansas, Kansas City, Kansas
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13
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Oaks J, Ogretmen B. Regulation of PP2A by Sphingolipid Metabolism and Signaling. Front Oncol 2015; 4:388. [PMID: 25642418 PMCID: PMC4295541 DOI: 10.3389/fonc.2014.00388] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 12/27/2014] [Indexed: 12/21/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that is a primary regulator of cellular proliferation through targeting of proliferative kinases, cell cycle regulators, and apoptosis inhibitors. It is through the regulation of these regulatory elements that gives PP2A tumor suppressor functions. In addition to mutations on the regulatory subunits, the phosphatase/tumor suppressing activity of PP2A is also inhibited in several cancer types due to overexpression or modification of the endogenous PP2A inhibitors such as SET/I2PP2A. This review focuses on the current literature regarding the interactions between the lipid signaling molecules, selectively sphingolipids, and the PP2A inhibitor SET for the regulation of PP2A, and the therapeutic potential of sphingolipids as PP2A activators for tumor suppression via targeting SET oncoprotein.
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Affiliation(s)
- Joshua Oaks
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina , Charleston, SC , USA
| | - Besim Ogretmen
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina , Charleston, SC , USA
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14
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Rego A, Trindade D, Chaves SR, Manon S, Costa V, Sousa MJ, Côrte-Real M. The yeast model system as a tool towards the understanding of apoptosis regulation by sphingolipids. FEMS Yeast Res 2013; 14:160-78. [DOI: 10.1111/1567-1364.12096] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/02/2013] [Accepted: 09/06/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- António Rego
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
- Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Dário Trindade
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
- CNRS; UMR5095; Université de Bordeaux 2; Bordeaux France
| | - Susana R. Chaves
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
| | - Stéphen Manon
- CNRS; UMR5095; Université de Bordeaux 2; Bordeaux France
| | - Vítor Costa
- Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; Instituto de Ciências Biomédicas Abel Salazar; Universidade do Porto; Porto Portugal
| | - Maria João Sousa
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
| | - Manuela Côrte-Real
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
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15
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Tanoue K, Miller Jenkins LM, Durell SR, Debnath S, Sakai H, Tagad HD, Ishida K, Appella E, Mazur SJ. Binding of a third metal ion by the human phosphatases PP2Cα and Wip1 is required for phosphatase activity. Biochemistry 2013; 52:5830-43. [PMID: 23906386 DOI: 10.1021/bi4005649] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The PPM phosphatases require millimolar concentrations of Mg²⁺ or Mn²⁺ to activate phosphatase activity in vitro. The human phosphatases PP2Cα (PPM1A) and Wip1 (PPM1D) differ in their physiological function, substrate specificity, and apparent metal affinity. A crystallographic structure of PP2Cα shows only two metal ions in the active site. However, recent structural studies of several bacterial PP2C phosphatases have indicated three metal ions in the active site. Two residues that coordinate the third metal ion are highly conserved, suggesting that human PP2C phosphatases may also bind a third ion. Here, isothermal titration calorimetry analysis of Mg²⁺ binding to PP2Cα distinguished binding of two ions to high affinity sites from the binding of a third ion with a millimolar affinity, similar to the apparent metal affinity required for catalytic activity. Mutational analysis indicated that Asp239 and either Asp146 or Asp243 was required for low-affinity binding of Mg²⁺, but that both Asp146 and Asp239 were required for catalysis. Phosphatase activity assays in the presence of MgCl₂, MnCl₂, or mixtures of the two, demonstrate high phosphatase activity toward a phosphopeptide substrate when Mg²⁺ was bound to the low-affinity site, whether Mg²⁺ or Mn²⁺ ions were bound to the high affinity sites. Mutation of the corresponding putative third metal ion-coordinating residues of Wip1 affected catalytic activity similarly both in vitro and in human cells. These results suggest that phosphatase activity toward phosphopeptide substrates by PP2Cα and Wip1 requires the binding of a Mg²⁺ ion to the low-affinity site.
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Affiliation(s)
- Kan Tanoue
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
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16
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Neubauer HA, Pitson SM. Roles, regulation and inhibitors of sphingosine kinase 2. FEBS J 2013; 280:5317-36. [PMID: 23638983 DOI: 10.1111/febs.12314] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 04/29/2013] [Accepted: 04/29/2013] [Indexed: 12/19/2022]
Abstract
The bioactive sphingolipids ceramide, sphingosine and sphingosine-1-phosphate (S1P) are important signalling molecules that regulate a diverse array of cellular processes. Most notably, the balance of the levels of these three sphingolipids in cells, termed the 'sphingolipid rheostat', can dictate cell fate, where ceramide and sphingosine enhance apoptosis and S1P promotes cell survival and proliferation. The sphingosine kinases (SKs) catalyse the production of S1P from sphingosine and are therefore central regulators of the sphingolipid rheostat and attractive targets for cancer therapy. Two SKs exist in humans: SK1 and SK2. SK1 has been extensively studied and there is a large body of evidence to demonstrate its role in promoting cell survival, proliferation and neoplastic transformation. SK1 is also elevated in many human cancers which appears to contribute to carcinogenesis, chemotherapeutic resistance and poor patient outcome. SK2, however, has not been as well characterized, and there are contradictions in the key physiological functions that have been proposed for this isoform. Despite this, many studies are now emerging that implicate SK2 in key roles in a variety of diseases, including the development of a range of solid tumours. Here, we review the literature examining SK2, its physiological and pathophysiological functions, the current knowledge of its regulation, and recent developments in targeting this complex enzyme.
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Affiliation(s)
- Heidi A Neubauer
- Centre for Cancer Biology, SA Pathology, Adelaide, Australia; School of Molecular and Biomedical Science, University of Adelaide, Australia
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17
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Hage-Sleiman R, Esmerian MO, Kobeissy H, Dbaibo G. p53 and Ceramide as Collaborators in the Stress Response. Int J Mol Sci 2013; 14:4982-5012. [PMID: 23455468 PMCID: PMC3634419 DOI: 10.3390/ijms14034982] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 01/22/2013] [Accepted: 02/01/2013] [Indexed: 02/08/2023] Open
Abstract
The sphingolipid ceramide mediates various cellular processes in response to several extracellular stimuli. Some genotoxic stresses are able to induce p53-dependent ceramide accumulation leading to cell death. However, in other cases, in the absence of the tumor suppressor protein p53, apoptosis proceeds partly due to the activity of this "tumor suppressor lipid", ceramide. In the current review, we describe ceramide and its roles in signaling pathways such as cell cycle arrest, hypoxia, hyperoxia, cell death, and cancer. In a specific manner, we are elaborating on the role of ceramide in mitochondrial apoptotic cell death signaling. Furthermore, after highlighting the role and mechanism of action of p53 in apoptosis, we review the association of ceramide and p53 with respect to apoptosis. Strikingly, the hypothesis for a direct interaction between ceramide and p53 is less favored. Recent data suggest that ceramide can act either upstream or downstream of p53 protein through posttranscriptional regulation or through many potential mediators, respectively.
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Affiliation(s)
- Rouba Hage-Sleiman
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mails: (M.O.E.); (G.D.)
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +961-1-350-000 (ext. 4883)
| | - Maria O. Esmerian
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mails: (M.O.E.); (G.D.)
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mail:
| | - Hadile Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mail:
| | - Ghassan Dbaibo
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Infectious Diseases, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mails: (M.O.E.); (G.D.)
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Riad El Solh, 1107 2020 Beirut, Lebanon; E-Mail:
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18
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Jung JS, Shin KO, Lee YM, Shin JA, Park EM, Jeong J, Kim DH, Choi JW, Kim HS. Anti-inflammatory mechanism of exogenous C2 ceramide in lipopolysaccharide-stimulated microglia. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1016-26. [PMID: 23384839 DOI: 10.1016/j.bbalip.2013.01.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/17/2013] [Accepted: 01/28/2013] [Indexed: 01/04/2023]
Abstract
Ceramide is a major molecule among the sphingolipid metabolites which are produced in the brain and other organs and act as intracellular second messengers. Although a variety of physiological roles of ceramide have been reported in the periphery and central nervous systems, the role of ceramide in microglial activation has not been clearly demonstrated. In the present study, we examined the effects of exogenous cell permeable short chain ceramides on microglial activation in vitro and in vivo. We found that C2, C6, and C8 ceramide and C8 ceramide-1-phosphate inhibited iNOS and proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated BV2 microglial cells and rat primary microglia. In addition, the administration of C2 ceramide suppressed microglial activation in the brains of LPS-exposed mice. By HPLC and LC/MS/MS analyses, we found that C2 ceramide on its own, rather than its modified form (i.e. ceramide-1-phosphate or long chain ceramides), mainly work by penetrating into microglial cells. Further mechanistic studies by using the most effective C2 ceramide among the short chain ceramides tested, revealed that C2 ceramide exerts anti-inflammatory effects via inhibition of the ROS, MAPKs, PI3K/Akt, and Jak/STAT pathways with upregulation of PKA and hemeoxygenase-1 expressions. Interestingly, we found that C2 ceramide inhibits TLR4 signaling by interfering with LPS and TLR4 interactions. Therefore, our data collectively suggests the therapeutic potential of short chain ceramides such as C2 for neuroinflammatory disorders such as Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Ji-Sun Jung
- Department of Molecular Medicine, Ewha Womans University Medical School, Seoul, Republic of Korea
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19
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De Munter S, Köhn M, Bollen M. Challenges and opportunities in the development of protein phosphatase-directed therapeutics. ACS Chem Biol 2013; 8:36-45. [PMID: 23214403 DOI: 10.1021/cb300597g] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein phosphatases have both protective and promoting roles in the etiology of diseases. A prominent example is the existence of oncogenic as well as tumor-suppressing protein phosphatases. A few protein phosphatase activity modulators are already applied in therapies. These were however not developed in target-directed approaches, and the recent discovery of phosphatase involvement followed their application in therapy. Nevertheless, these examples demonstrate that small molecules can be generated that modulate the activity of protein phosphatases and are beneficial for the treatment of protein phosphorylation diseases. We describe here strategies for the development of activators and inhibitors of protein phosphatases and clarify some long-standing misconceptions concerning the druggability of these enzymes. Recent developments suggest that it is feasible to design potent and selective protein phosphatase modulators with a therapeutic potential.
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Affiliation(s)
- Sofie De Munter
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Maja Köhn
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg,
Germany
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
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