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Luo S, Luo Y, Wang Z, Yin H, Wu Q, Du X, Xie X. Super-enhancer mediated upregulation of MYEOV suppresses ferroptosis in lung adenocarcinoma. Cancer Lett 2024; 589:216811. [PMID: 38490328 DOI: 10.1016/j.canlet.2024.216811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/02/2024] [Accepted: 03/09/2024] [Indexed: 03/17/2024]
Abstract
Super-enhancers (SEs) exerted a crucial role in regulating the transcription of oncogenes across various malignancies while the roles of SEs driven genes and the core regulatory elements remain elusive in LUAD. In this study, cancer-specific-SE-genes of lung adenocarcinoma (LUAD) were profiled through H3K27ac ChIP-seq data of cancer cell lines and normal lung tissues, which enriched in in biological processes and pathways integral to the pathophysiology of LUAD. Based on this study, LUAD cells were susceptible to SEs inhibitors, with a reduction of cell proliferation as well as an elevation of apoptosis upon JQ1 or THZ1 intervention. Moreover, the integration of SEs landscapes, CRISPRi, ChIP-PCR, Hi-C data analysis and dual-luciferase reporter assays revealed that myeloma overexpressed gene (MYEOV) was aberrantly overexpressed in LUAD via transcriptional activation by the core SE elements. Functionally, the knockdown of MYEOV undermined cell proliferation in vitro and tumor growth in vivo. In addition, the knockdown of MYEOV generated a prominent ferroptotic phenotype, characterized by elevation of intracellular ferrous iron, reactive oxygen species and lipid peroxidation, together with alteration in marker proteins (SLC7A11, GPX4, FTH1, and ACSL4). Instead, the overexpression of MYEOV accelerated cell proliferation and abrogated ferroptosis. Clinically, the overexpression of MYEOV was observed in LUAD tissues indicating a poor prognosis in patients with LUAD. Mechanistically, SMPD1-induced autophagic degradation of GPX4 assumed a crucial role in the process of ferroptosis triggered by MYEOV knockdown. Serving as an oncogene repressing ferroptosis, promoting proliferation as well as shortening survival in LUAD, SEs-mediated activation of MYEOV might distinguish as a promising therapeutic target.
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Affiliation(s)
- Shuimei Luo
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Yang Luo
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Ziming Wang
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Haofeng Yin
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Qing Wu
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Xiaowei Du
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China
| | - Xianhe Xie
- Department of Oncology, Molecular Oncology Research Institute, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China; Department of Oncology, National Regional Medical Center, Binhai Campus of The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350212, China; Fujian Key Laboratory of Precision Medicine for Cancer, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, 350000, China.
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Das K, Keshava S, Kolesnick R, Pendurthi UR, Rao LVM. MicroRNA-10a enrichment in factor VIIa-released endothelial extracellular vesicles: potential mechanisms. J Thromb Haemost 2024; 22:441-454. [PMID: 37926194 PMCID: PMC10872460 DOI: 10.1016/j.jtha.2023.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/09/2023] [Accepted: 10/24/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND Factor VIIa induces the release of extracellular vesicles (EVs) from endothelial cells (EEVs). Factor VIIa-released EEVs are enriched with microRNA-10a (miR10a) and elicit miR10a-dependent cytoprotective responses. OBJECTIVES To investigate mechanisms by which FVIIa induces miR10a expression in endothelial cells and sorts miR10a into the EVs. METHODS Activation of Elk-1 and TWIST1 expression was analyzed by immunofluorescence microscopy and immunoblot analysis. Small interfering RNA silencing approach was used to knock down the expression of specific genes in endothelial cells. EVs secreted from endothelial cells or released into circulation in mice were isolated by centrifugation and quantified by nanoparticle tracking analysis. Factor VIIa or EVs were injected into mice; mice were challenged with lipopolysaccharides to assess the cytoprotective effects of FVIIa or EVs. RESULTS FVIIa activation of ERK1/2 triggered the activation of Elk-1, which led to the induction of TWIST1, a key transcription factor involved in miR10a expression. Factor VIIa also induced the expression of La, a small RNA-binding protein. Factor VIIa-driven acid sphingomyelinase (ASM) activation and the subsequent activation of the S1P receptor pathway were responsible for the induction of La. Silencing of ASM or La significantly reduced miR10a levels in FVIIa-released EEVs without affecting the cellular expression of miR10a. Factor VIIa-EEVs from ASM knocked-down cells failed to provide cytoprotective responses in cell and murine model systems. Administration of FVIIa protected wild-type but not ASM-/- mice against lipopolysaccharide-induced inflammation and vascular leakage. CONCLUSION Our data suggest that enhanced cellular expression of miR10a coupled with La-dependent sorting of miR10a is responsible for enriching FVIIa-released EVs with miR10a.
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Affiliation(s)
- Kaushik Das
- Department of Cellular and Molecular Biology, UT Tyler School of Medicine, the University of Texas Health Science Center at Tyler, Tyler, Texas, USA
| | - Shiva Keshava
- Department of Cellular and Molecular Biology, UT Tyler School of Medicine, the University of Texas Health Science Center at Tyler, Tyler, Texas, USA
| | | | - Usha R Pendurthi
- Department of Cellular and Molecular Biology, UT Tyler School of Medicine, the University of Texas Health Science Center at Tyler, Tyler, Texas, USA
| | - L Vijaya Mohan Rao
- Department of Cellular and Molecular Biology, UT Tyler School of Medicine, the University of Texas Health Science Center at Tyler, Tyler, Texas, USA.
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Mir IH, Thirunavukkarasu C. The relevance of acid sphingomyelinase as a potential target for therapeutic intervention in hepatic disorders: current scenario and anticipated trends. Arch Toxicol 2023; 97:2069-2087. [PMID: 37248308 PMCID: PMC10226719 DOI: 10.1007/s00204-023-03529-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/22/2023] [Indexed: 05/31/2023]
Abstract
Acid sphingomyelinase (ASMase) serves as one of the most remarkable enzymes in sphingolipid biology. ASMase facilitates the hydrolysis of sphingomyelin, yielding ceramide and phosphorylcholine via the phospholipase C signal transduction pathway. Owing to its prominent intervention in apoptosis, ASMase, and its product ceramide is now at the bleeding edge of lipid research due to the coalesced efforts of several research institutions over the past 40 years. ASMase-catalyzed ceramide synthesis profoundly alters the physiological properties of membrane structure in response to a broad range of stimulations, orchestrating signaling cascades for endoplasmic reticulum stress, autophagy, and lysosomal membrane permeabilization, which influences the development of hepatic disorders, such as steatohepatitis, hepatic fibrosis, drug-induced liver injury, and hepatocellular carcinoma. As a result, the potential to modulate the ASMase action with appropriate pharmaceutical antagonists has sparked a lot of curiosity. This article emphasizes the fundamental mechanisms of the systems that govern ASMase aberrations in various hepatic pathologies. Furthermore, we present an insight into the potential therapeutic agents used to mitigate ASMase irregularities and the paramountcy of such inhibitors in drug repurposing.
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Affiliation(s)
- Ishfaq Hassan Mir
- Department of Biochemistry and Molecular Biology, Pondicherry University, Puducherry, 605 014, India
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Pauletto PJT, Delgado CP, da Rocha JBT. Acid sphingomyelinase (ASM) and COVID-19: A review of the potential use of ASM inhibitors against SARS-CoV-2. Cell Biochem Funct 2023; 41:284-295. [PMID: 36929117 DOI: 10.1002/cbf.3789] [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: 07/20/2022] [Revised: 02/16/2023] [Accepted: 02/26/2023] [Indexed: 03/18/2023]
Abstract
In the last 2 years, different pharmacological agents have been indicated as potential inhibitors of SARS-CoV-2 in vitro. Specifically, drugs termed as functional inhibitors of acid sphingomyelinase (FIASMAs) have proved to inhibit the SARS-CoV-2 replication using different types of cells. Those therapeutic agents share several chemical structure characteristics and some well-known representatives are fluoxetine, escitalopram, fluvoxamine, and others. Most of the FIASMAs are primarily used as effective therapeutic agents to treat different pathologies, therefore, they are natural drug candidates for repositioning strategy. In this review, we summarize the two main proposed mechanisms mediating acid sphingomyelinase (ASM) inhibition and how they can explain the inhibition of SARS-CoV-2 replication by FIASMAs. The first mechanism implies a disruption in the lysosomal pH fall as the endosome-lysosome moves toward the interior of the cell. In fact, changes in cholesterol levels in endosome-lysosome membranes, which are associated with ASM inhibition is thought to be mediated by lysosomal proton pump (ATP-ase) inactivation. The second mechanism involves the formation of an extracellular ceramide-rich domain, which is blocked by FIASMAs. The ceramide-rich domains are believed to facilitate the SARS-CoV-2 entrance into the host cells.
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Affiliation(s)
- Pedro José Tronco Pauletto
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Cassia Pereira Delgado
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - João Batista Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
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Wang R, Qin Z, Huang L, Luo H, Peng H, Zhou X, Zhao Z, Liu M, Yang P, Shi T. SMPD1 expression profile and mutation landscape help decipher genotype-phenotype association and precision diagnosis for acid sphingomyelinase deficiency. Hereditas 2023; 160:11. [PMID: 36907956 PMCID: PMC10009935 DOI: 10.1186/s41065-023-00272-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/28/2023] [Indexed: 03/14/2023] Open
Abstract
BACKGROUND Acid sphingomyelinase deficiency (ASMD) disorder, also known as Niemann-Pick disease (NPD) is a rare genetic disease caused by mutations in SMPD1 gene, which encodes sphingomyelin phosphodiesterase (ASM). Except for liver and spleen enlargement and lung disease, two subtypes (Type A and B) of NDP have different onset times, survival times, ASM activities, and neurological abnormalities. To comprehensively explore NPD's genotype-phenotype association and pathophysiological characteristics, we collected 144 NPD cases with strict quality control through literature mining. RESULTS The difference in ASM activity can differentiate NPD type A from other subtypes, with the ratio of ASM activity to the reference values being lower in type A (threshold 0.045 (4.45%)). Severe variations, such as deletion and insertion, can cause complete loss of ASM function, leading to type A, whereas relatively mild missense mutations generally result in type B. Among reported mutations, the p.Arg3AlafsX76 mutation is highly prevalent in the Chinese population, and the p.R608del mutation is common in Mediterranean countries. The expression profiles of SMPD1 from GTEx and single-cell RNA sequencing data of multiple fetal tissues showed that high expressions of SMPD1 can be observed in the liver, spleen, and brain tissues of adults and hepatoblasts, hematopoietic stem cells, STC2_TLX1-positive cells, mesothelial cells of the spleen, vascular endothelial cells of the cerebellum and the cerebrum of fetuses, indicating that SMPD1 dysfunction is highly likely to have a significant effect on the function of those cell types during development and the clinicians need pay attention to these organs or tissues as well during diagnosis. In addition, we also predicted 21 new pathogenic mutations in the SMPD1 gene that potentially cause the NPD, signifying that more rare cases will be detected with those mutations in SMPD1. Finally, we also analysed the function of the NPD type A cells following the extracellular milieu. CONCLUSIONS Our study is the first to elucidate the effects of SMPD1 mutation on cell types and at the tissue level, which provides new insights into the genotype-phenotype association and can help in the precise diagnosis of NPD.
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Affiliation(s)
- Ruisong Wang
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
- Affiliated Hospital of Hunan University of Arts and Science (the Maternal and Child Health Hospital), Medical college, 3150 Dongting Ave., Changde, Hunan Province, People's Republic of China, 415000
| | - Ziyi Qin
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Long Huang
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Huiling Luo
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Han Peng
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Xinyu Zhou
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Zhixiang Zhao
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Mingyao Liu
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
- Changde Research Centre for Artificial Intelligence and Biomedicine, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China
| | - Pinhong Yang
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China.
- Changde Research Centre for Artificial Intelligence and Biomedicine, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China.
| | - Tieliu Shi
- College of Life and Environmental Sciences, Hunan University of Arts and Science, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China.
- Changde Research Centre for Artificial Intelligence and Biomedicine, 3150 Dongting Ave., Changde, 415000, Hunan Province, People's Republic of China.
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6
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Pfrieger FW. The Niemann-Pick type diseases – A synopsis of inborn errors in sphingolipid and cholesterol metabolism. Prog Lipid Res 2023; 90:101225. [PMID: 37003582 DOI: 10.1016/j.plipres.2023.101225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
Disturbances of lipid homeostasis in cells provoke human diseases. The elucidation of the underlying mechanisms and the development of efficient therapies represent formidable challenges for biomedical research. Exemplary cases are two rare, autosomal recessive, and ultimately fatal lysosomal diseases historically named "Niemann-Pick" honoring the physicians, whose pioneering observations led to their discovery. Acid sphingomyelinase deficiency (ASMD) and Niemann-Pick type C disease (NPCD) are caused by specific variants of the sphingomyelin phosphodiesterase 1 (SMPD1) and NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2) genes that perturb homeostasis of two key membrane components, sphingomyelin and cholesterol, respectively. Patients with severe forms of these diseases present visceral and neurologic symptoms and succumb to premature death. This synopsis traces the tortuous discovery of the Niemann-Pick diseases, highlights important advances with respect to genetic culprits and cellular mechanisms, and exposes efforts to improve diagnosis and to explore new therapeutic approaches.
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7
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Lin G, Tepe B, McGrane G, Tipon RC, Croft G, Panwala L, Hope A, Liang AJH, Zuo Z, Byeon SK, Wang L, Pandey A, Bellen HJ. Exploring therapeutic strategies for infantile neuronal axonal dystrophy (INAD/PARK14). eLife 2023; 12:82555. [PMID: 36645408 PMCID: PMC9889087 DOI: 10.7554/elife.82555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/15/2023] [Indexed: 01/17/2023] Open
Abstract
Infantile neuroaxonal dystrophy (INAD) is caused by recessive variants in PLA2G6 and is a lethal pediatric neurodegenerative disorder. Loss of the Drosophila homolog of PLA2G6, leads to ceramide accumulation, lysosome expansion, and mitochondrial defects. Here, we report that retromer function, ceramide metabolism, the endolysosomal pathway, and mitochondrial morphology are affected in INAD patient-derived neurons. We show that in INAD mouse models, the same features are affected in Purkinje cells, arguing that the neuropathological mechanisms are evolutionary conserved and that these features can be used as biomarkers. We tested 20 drugs that target these pathways and found that Ambroxol, Desipramine, Azoramide, and Genistein alleviate neurodegenerative phenotypes in INAD flies and INAD patient-derived neural progenitor cells. We also develop an AAV-based gene therapy approach that delays neurodegeneration and prolongs lifespan in an INAD mouse model.
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Affiliation(s)
- Guang Lin
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Burak Tepe
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Geoff McGrane
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | - Regine C Tipon
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | - Gist Croft
- New York Stem Cell Foundation Research InstituteNew YorkUnited States
| | | | | | - Agnes JH Liang
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Seul Kee Byeon
- Department of Laboratory Medicine and Pathology, Mayo ClinicRochesterUnited States
| | - Lily Wang
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo ClinicRochesterUnited States
- Manipal Academy of Higher Education, ManipalKarnatakaIndia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
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8
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Mächtel R, Boros FA, Dobert JP, Arnold P, Zunke F. From Lysosomal Storage Disorders to Parkinson's Disease - Challenges and Opportunities. J Mol Biol 2022:167932. [PMID: 36572237 DOI: 10.1016/j.jmb.2022.167932] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Lysosomes are specialized organelles with an acidic pH that act as recycling hubs for intracellular and extracellular components. They harbour numerous different hydrolytic enzymes to degrade substrates like proteins, peptides, and glycolipids. Reduced catalytic activity of lysosomal enzymes can cause the accumulation of these substrates and loss of lysosomal integrity, resulting in lysosomal dysfunction and lysosomal storage disorders (LSDs). Post-mitotic cells, such as neurons, seem to be highly sensitive to damages induced by lysosomal dysfunction, thus LSDs often manifest with neurological symptoms. Interestingly, some LSDs and Parkinson's disease (PD) share common cellular pathomechanisms, suggesting convergence of aetiology of the two disease types. This is further underlined by genetic associations of several lysosomal genes involved in LSDs with PD. The increasing number of lysosome-associated genetic risk factors for PD makes it necessary to understand functions and interactions of lysosomal proteins/enzymes both in health and disease, thereby holding the potential to identify new therapeutic targets. In this review, we highlight genetic and mechanistic interactions between the complex lysosomal network, LSDs and PD, and elaborate on methodical challenges in lysosomal research.
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Affiliation(s)
- Rebecca Mächtel
- Department of Molecular Neurology, University Clinics Erlangen, Erlangen, Germany
| | | | - Jan Philipp Dobert
- Department of Molecular Neurology, University Clinics Erlangen, Erlangen, Germany
| | - Philipp Arnold
- Institute of Functional and Clinical Anatomy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Friederike Zunke
- Department of Molecular Neurology, University Clinics Erlangen, Erlangen, Germany.
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Ueda S, Manabe Y, Kubo N, Morino N, Yuasa H, Shiotsu M, Tsuji T, Sugawara T, Kambe T. Early secretory pathway-resident Zn transporter proteins contribute to cellular sphingolipid metabolism through activation of sphingomyelin phosphodiesterase 1. Am J Physiol Cell Physiol 2022; 322:C948-C959. [PMID: 35294847 DOI: 10.1152/ajpcell.00020.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sphingomyelin phosphodiesterase 1 (SMPD1) converts sphingomyelin into ceramide and phosphocholine; hence, loss of SMPD1 function causes abnormal accumulation of sphingomyelin in lysosomes, which results in the lipid-storage disorder Niemann-Pick disease (types A and B). SMPD1 activity is dependent on zinc, which is coordinated at the active site of the enzyme, and although SMPD1 has been suggested to acquire zinc at the sites where the enzyme is localized, precisely how SMPD1 acquires zinc remains to be clarified. Here, we addressed this using a gene-disruption/re-expression strategy. Our results revealed that Zn transporter 5 (ZNT5)-ZNT6 heterodimers and ZNT7 homodimers, which localize in the compartments of the early secretory pathway, play essential roles in SMPD1 activation. Both ZNT complexes contribute to cellular sphingolipid metabolism by activating SMPD1 because cells lacking the functions of the two complexes exhibited a reduced ceramide to sphingomyelin content ratio in terms of their dominant molecular species and an increase in the sphingomyelin content in terms of three minor species. Moreover, mutant cells contained multilamellar body-like structures, indicative of membrane stacking and accumulation, in the cytoplasm. These findings provide novel insights into the molecular mechanism underlying the activation of SMPD1, a key enzyme in sphingolipid metabolism.
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Affiliation(s)
- Sachiko Ueda
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yuki Manabe
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Naoya Kubo
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Naho Morino
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hana Yuasa
- Department of Food Science and Biotechnology, Faculty of Agriculture, Kyoto University, Kyoto, Japan
| | - Miku Shiotsu
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tokuji Tsuji
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tatsuya Sugawara
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Administration of an Acidic Sphingomyelinase (ASMase) Inhibitor, Imipramine, Reduces Hypoglycemia-Induced Hippocampal Neuronal Death. Cells 2022; 11:cells11040667. [PMID: 35203316 PMCID: PMC8869983 DOI: 10.3390/cells11040667] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/31/2022] [Accepted: 02/12/2022] [Indexed: 01/27/2023] Open
Abstract
Severe hypoglycemia (below 35 mg/dL) appears most often in diabetes patients who continuously inject insulin. To rapidly cease the hypoglycemic state in this study, glucose reperfusion was conducted, which can induce a secondary neuronal death cascade following hypoglycemia. Acid sphingomyelinase (ASMase) hydrolyzes sphingomyelin into ceramide and phosphorylcholine. ASMase activity can be influenced by cations, pH, redox, lipids, and other proteins in the cells, and there are many changes in these factors in hypoglycemia. Thus, we expect that ASMase is activated excessively after hypoglycemia. Ceramide is known to cause free radical production, excessive inflammation, calcium dysregulation, and lysosomal injury, resulting in apoptosis and the necrosis of neurons. Imipramine is mainly used in the treatment of depression and certain anxiety disorders, and it is particularly known as an ASMase inhibitor. We hypothesized that imipramine could decrease hippocampal neuronal death by reducing ceramide via the inhibition of ASMase after hypoglycemia. In the present study, we confirmed that the administration of imipramine significantly reduced hypoglycemia-induced neuronal death and improved cognitive function. Therefore, we suggest that imipramine may be a promising therapeutic tool for preventing hypoglycemia-induced neuronal death.
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11
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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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12
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Breiden B, Sandhoff K. Acid Sphingomyelinase, a Lysosomal and Secretory Phospholipase C, Is Key for Cellular Phospholipid Catabolism. Int J Mol Sci 2021; 22:9001. [PMID: 34445706 PMCID: PMC8396676 DOI: 10.3390/ijms22169001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/14/2021] [Accepted: 08/16/2021] [Indexed: 02/06/2023] Open
Abstract
Here, we present the main features of human acid sphingomyelinase (ASM), its biosynthesis, processing and intracellular trafficking, its structure, its broad substrate specificity, and the proposed mode of action at the surface of the phospholipid substrate carrying intraendolysosomal luminal vesicles. In addition, we discuss the complex regulation of its phospholipid cleaving activity by membrane lipids and lipid-binding proteins. The majority of the literature implies that ASM hydrolyses solely sphingomyelin to generate ceramide and ignores its ability to degrade further substrates. Indeed, more than twenty different phospholipids are cleaved by ASM in vitro, including some minor but functionally important phospholipids such as the growth factor ceramide-1-phosphate and the unique lysosomal lysolipid bis(monoacylglycero)phosphate. The inherited ASM deficiency, Niemann-Pick disease type A and B, impairs mainly, but not only, cellular sphingomyelin catabolism, causing a progressive sphingomyelin accumulation, which furthermore triggers a secondary accumulation of lipids (cholesterol, glucosylceramide, GM2) by inhibiting their turnover in late endosomes and lysosomes. However, ASM appears to be involved in a variety of major cellular functions with a regulatory significance for an increasing number of metabolic disorders. The biochemical characteristics of ASM, their potential effect on cellular lipid turnover, as well as a potential impact on physiological processes will be discussed.
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Affiliation(s)
| | - Konrad Sandhoff
- Membrane Biology and Lipid Biochemistry Unit, LIMES Institute, University of Bonn, 53121 Bonn, Germany
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13
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Ilnytska O, Lai K, Gorshkov K, Schultz ML, Tran BN, Jeziorek M, Kunkel TJ, Azaria RD, McLoughlin HS, Waghalter M, Xu Y, Schlame M, Altan-Bonnet N, Zheng W, Lieberman AP, Dobrowolski R, Storch J. Enrichment of NPC1-deficient cells with the lipid LBPA stimulates autophagy, improves lysosomal function, and reduces cholesterol storage. J Biol Chem 2021; 297:100813. [PMID: 34023384 PMCID: PMC8294588 DOI: 10.1016/j.jbc.2021.100813] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 04/29/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
Niemann-Pick C (NPC) is an autosomal recessive disorder characterized by mutations in the NPC1 or NPC2 genes encoding endolysosomal lipid transport proteins, leading to cholesterol accumulation and autophagy dysfunction. We have previously shown that enrichment of NPC1-deficient cells with the anionic lipid lysobisphosphatidic acid (LBPA; also called bis(monoacylglycerol)phosphate) via treatment with its precursor phosphatidylglycerol (PG) results in a dramatic decrease in cholesterol storage. However, the mechanisms underlying this reduction are unknown. In the present study, we showed using biochemical and imaging approaches in both NPC1-deficient cellular models and an NPC1 mouse model that PG incubation/LBPA enrichment significantly improved the compromised autophagic flux associated with NPC1 disease, providing a route for NPC1-independent endolysosomal cholesterol mobilization. PG/LBPA enrichment specifically enhanced the late stages of autophagy, and effects were mediated by activation of the lysosomal enzyme acid sphingomyelinase. PG incubation also led to robust and specific increases in LBPA species with polyunsaturated acyl chains, potentially increasing the propensity for membrane fusion events, which are critical for late-stage autophagy progression. Finally, we demonstrated that PG/LBPA treatment efficiently cleared cholesterol and toxic protein aggregates in Purkinje neurons of the NPC1I1061T mouse model. Collectively, these findings provide a mechanistic basis supporting cellular LBPA as a potential new target for therapeutic intervention in NPC disease.
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Affiliation(s)
- Olga Ilnytska
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA; Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey, USA.
| | - Kimberly Lai
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Kirill Gorshkov
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark L Schultz
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Bruce Nguyen Tran
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Maciej Jeziorek
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Thaddeus J Kunkel
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ruth D Azaria
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hayley S McLoughlin
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Miriam Waghalter
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Yang Xu
- Departments of Anesthesiology and Cell Biology, New York University School of Medicine, New York, New York, USA
| | - Michael Schlame
- Departments of Anesthesiology and Cell Biology, New York University School of Medicine, New York, New York, USA
| | - Nihal Altan-Bonnet
- Laboratory of Host-Pathogen Dynamics, National Heart, Lung and Blood Institute, Bethesda, Maryland, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Radek Dobrowolski
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA; Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey, USA
| | - Judith Storch
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA; Rutgers Center for Lipid Research, Rutgers University, New Brunswick, New Jersey, USA.
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14
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Xiang H, Jin S, Tan F, Xu Y, Lu Y, Wu T. Physiological functions and therapeutic applications of neutral sphingomyelinase and acid sphingomyelinase. Biomed Pharmacother 2021; 139:111610. [PMID: 33957567 DOI: 10.1016/j.biopha.2021.111610] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/05/2021] [Accepted: 04/12/2021] [Indexed: 11/15/2022] Open
Abstract
Sphingomyelin (SM) can be converted into ceramide (Cer) by neutral sphingomyelinase (NSM) and acid sphingomyelinase (ASM). Cer is a second messenger of lipids and can regulate cell growth and apoptosis. Increasing evidence shows that NSM and ASM play key roles in many processes, such as apoptosis, immune function and inflammation. Therefore, NSM and ASM have broad prospects in clinical treatments, especially in cancer, cardiovascular diseases (such as atherosclerosis), nervous system diseases (such as Alzheimer's disease), respiratory diseases (such as chronic obstructive pulmonary disease) and the phenotype of dwarfisms in adolescents, playing a complex regulatory role. This review focuses on the physiological functions of NSM and ASM and summarizes their roles in certain diseases and their potential applications in therapy.
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Affiliation(s)
- Hongjiao Xiang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Shengjie Jin
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Fenglang Tan
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yifan Xu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yifei Lu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tao Wu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
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15
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Canals D, Salamone S, Santacreu BJ, Aguilar D, Hernandez-Corbacho MJ, Ostermeyer-Fay AG, Greene M, Nemeth E, Haley JD, Obeid LM, Hannun YA. The doxorubicin-induced cell motility network is under the control of the ceramide-activated protein phosphatase 1 alpha. FASEB J 2021; 35:e21396. [PMID: 33583073 PMCID: PMC8220868 DOI: 10.1096/fj.202002427r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 12/20/2022]
Abstract
We have recently reported that a specific pool of ceramide, located in the plasma membrane, mediated the effects of sublethal doses of the chemotherapeutic compound doxorubicin on enhancing cancer cell migration. We identified neutral sphingomyelinase 2 (nSMase2) as the enzyme responsible to generate this bioactive pool of ceramide. In this work, we explored the role of members of the protein phosphatases 1 family (PP1), and we identified protein phosphatase 1 alpha isoform (PP1 alpha) as the specific PP1 isoform to mediate this phenotype. Using a bioinformatics approach, we build a functional interaction network based on phosphoproteomics data on plasma membrane ceramide. This led to the identification of several ceramide-PP1 alpha downstream substrates. Studies on phospho mutants of ezrin (T567) and Scrib (S1378/S1508) demonstrated that their dephosphorylation is sufficient to enhance cell migration. In summary, we identified a mechanism where reduced doses of doxorubicin result in the dysregulation of cytoskeletal proteins and enhanced cell migration. This mechanism could explain the reported effects of doxorubicin worsening cancer metastasis in animal models.
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Affiliation(s)
- Daniel Canals
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Silvia Salamone
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Bruno Jaime Santacreu
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Facultad de Farmacia y Bioquimica, Catedra de Biologia Celular y Molecular, Buenos Aires, Argentina
| | - Daniel Aguilar
- Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBEREHD), Barcelona, Catalunya, Spain
| | | | | | - Meaghan Greene
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Erika Nemeth
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - John D. Haley
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Department of Pathology, Stony Brook University, NY, USA
| | - Lina M. Obeid
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Northport VA Hospital, Northport, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
| | - Yusuf A. Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA
- Stony Brook Cancer Center, Stony Brook, NY, USA
- Department of Biochemistry, Stony Brook University, Stony Brook, NY, USA
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16
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Xiong X, Lee CF, Li W, Yu J, Zhu L, Kim Y, Zhang H, Sun H. Acid Sphingomyelinase regulates the localization and trafficking of palmitoylated proteins. Biol Open 2019; 8:bio.040311. [PMID: 31142470 PMCID: PMC6826292 DOI: 10.1242/bio.040311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In human, loss of acid sphingomyelinase (ASM/SMPD1) causes Niemann–Pick disease, type A. ASM hydrolyzes sphingomyelins to produce ceramides but protein targets of ASM remain largely unclear. Our mass spectrometry-based proteomic analyses have identified >100 proteins associated with the ASM-dependent, detergent-resistant membrane microdomains (lipid rafts), with >60% of these proteins being palmitoylated, including SNAP23, Src-family kinases Yes and Lyn, and Ras and Rab family small GTPases. Inactivation of ASM abolished the presence of these proteins in the plasma membrane, with many of them trapped in the Golgi. While palmitoylation inhibitors and palmitoylation mutants phenocopied the effects of ASM inactivation, we demonstrated that ASM is required for the transport of palmitoylated proteins, such as SNAP23 and Lyn, from the Golgi to the plasma membrane without affecting palmitoylation directly. Importantly, ASM delivered extracellularly can regulate the trafficking of SNAP23 from the Golgi to the plasma membrane. Our studies suggest that ASM, acting at the plasma membrane to produce ceramides, regulates the localization and trafficking of the palmitoylated proteins. Summary: Acid sphingomyelinase (ASM) regulates palmitoylated protein trafficking and localization.
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Affiliation(s)
- Xiahui Xiong
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Chia-Fang Lee
- Protea Biosciences, 1311 Pineview drive, Morgantown, West Virginia, USA
| | - Wenjing Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Jiekai Yu
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Linyu Zhu
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Yongsoon Kim
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Hui Zhang
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
| | - Hong Sun
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154-4003, USA
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17
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Ramírez-Montiel F, Mendoza-Macías C, Andrade-Guillén S, Rangel-Serrano Á, Páramo-Pérez I, Rivera-Cuéllar PE, España-Sánchez BL, Luna-Bárcenas G, Anaya-Velázquez F, Franco B, Padilla-Vaca F. Plasma membrane damage repair is mediated by an acid sphingomyelinase in Entamoeba histolytica. PLoS Pathog 2019; 15:e1008016. [PMID: 31461501 PMCID: PMC6713333 DOI: 10.1371/journal.ppat.1008016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 08/02/2019] [Indexed: 12/15/2022] Open
Abstract
Entamoeba histolytica is a pathogen that during its infective process confronts the host defenses, which damages the amoebic plasma membrane (PM), resulting in the loss of viability. However, it is unknown whether amoebic trophozoites are able to repair their PM when it is damaged. Acid sphingomyelinases (aSMases) have been reported in mammalian cells to promote endocytosis and removal of PM lesions. In this work, six predicted amoebic genes encoding for aSMases were found to be transcribed in the HM1:IMSS strain, finding that the EhaSM6 gene is the most transcribed in basal growth conditions and rendered a functional protein. The secreted aSMase activity detected was stimulated by Mg+2 and inhibited by Co+2. Trophozoites that overexpress the EhaSM6 gene (HM1-SM6HA) exhibit an increase of 2-fold in the secreted aSMase activity. This transfectant trophozoites exposed to pore-forming molecules (SLO, Magainin, β-Defensin 2 and human complement) exhibited an increase from 6 to 25-fold in the secreted aSMase activity which correlated with higher amoebic viability in a Ca+2 dependent process. However, other agents that affect the PM such as hydrogen peroxide also induced an increase of secreted aSMase, but to a lesser extent. The aSMase6 enzyme is N- and C-terminal processed. Confocal and transmission electron microscopy showed that trophozoites treated with SLO presented a migration of lysosomes containing the aSMase towards the PM, inducing the formation of membrane patches and endosomes in the control strain. These cellular structures were increased in the overexpressing strain, indicating the involvement of the aSMase6 in the PM injury repair. The pore-forming molecules induced an increase in the expression of EhaSM1, 2, 5 and 6 genes, meanwhile, hydrogen peroxide induced an increase in all of them. In all the conditions evaluated, the EhaSM6 gene exhibited the highest levels of induction. Overall, these novel findings show that the aSMase6 enzyme from E. histolytica promotes the repair of the PM damaged with pore-forming molecules to prevent losing cell integrity. This novel system could act when encountered with the lytic defense systems of the host. The host-amoeba relationship is based on a series of interplays between host defense mechanisms and parasite survival strategies. While host cells elaborate diverse mechanisms for pathogen elimination, Entamoeba histolytica trophozoites have also developed complex strategies to counteract host immune response and facilitate its own survival while confronting host defenses. E. histolytica exposed to pore-forming proteins such as β-Defensin 2, human complement and Streptolysin O (SLO), increases the activity of secreted aSMase, which is related to greater amoebic viability. Other agents that affect plasma membrane (PM) may also increase secreted aSMase but to a lesser extent. SLO form pores in the PM of E. histolytica trophozoites that initiates the uncontrolled entry of Ca2+, recognized as the primary trigger for cell responses which favors the migration of the lysosomes to the periphery of the cell, fuses with the PM and release their content, including aSMase to the external side of the cell. The secreted aSMase favoring the internalization of the lesion for its degradation in phagolysosomes. During the early stages of PM damage, the pores are rapidly blocked by patch-like structures that prevent the lysis of the trophozoite and immediately begin internalizing the lesion. The aSMase6 overexpression favors the repair of the lesion and the survival of E. histolytica trophozoites. Pore-forming proteins induced an increase in the expression of EhaSM1, 2, 5 and 6 genes, meanwhile oxidative stress induced an increase in all of them. Here we report, for the first time, that E. histolytica possess a mechanism for PM damage repair mediated by aSMase similar to the system described in mammalian cells.
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Affiliation(s)
- Fátima Ramírez-Montiel
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Claudia Mendoza-Macías
- Departmento de Farmacia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Sairy Andrade-Guillén
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Ángeles Rangel-Serrano
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Itzel Páramo-Pérez
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Paris E. Rivera-Cuéllar
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - B. Liliana España-Sánchez
- CONACYT_Centro de Investigación y Desarrollo en Electroquímica (CIDETEQ) S.C. Parque Tecnológico, San Fandila, Querétaro, México
| | - Gabriel Luna-Bárcenas
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV) Unidad Querétaro, Fracc. Real de Juriquilla, Querétaro, Querétaro, México
| | - Fernando Anaya-Velázquez
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
| | - Bernardo Franco
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
- * E-mail: (BF); (FPV)
| | - Felipe Padilla-Vaca
- Departmento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Guanajuato, Mexico
- * E-mail: (BF); (FPV)
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18
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Andrews NW. Solving the secretory acid sphingomyelinase puzzle: Insights from lysosome-mediated parasite invasion and plasma membrane repair. Cell Microbiol 2019; 21:e13065. [PMID: 31155842 DOI: 10.1111/cmi.13065] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/03/2019] [Accepted: 05/30/2019] [Indexed: 12/19/2022]
Abstract
Acid sphingomyelinase (ASM) is a lysosomal enzyme that cleaves the phosphorylcholine head group of sphingomyelin, generating ceramide. Recessive mutations in SMPD1, the gene encoding ASM, cause Niemann-Pick Disease Types A and B. These disorders are attributed not only to lipid accumulation inside lysosomes but also to changes on the outer leaflet of the plasma membrane, highlighting an extracellular role for ASM. Secretion of ASM occurs under physiological conditions, and earlier studies proposed two forms of the enzyme, one resident in lysosomes and another form that would be diverted to the secretory pathway. Such differential intracellular trafficking has been difficult to explain because there is only one SMPD1 transcript that generates an active enzyme, found primarily inside lysosomes. Unexpectedly, studies of cell invasion by the protozoan parasite Trypanosoma cruzi revealed that conventional lysosomes can fuse with the plasma membrane in response to elevations in intracellular Ca2+ , releasing their contents extracellularly. ASM exocytosed from lysosomes remodels the outer leaflet of the plasma membrane, promoting parasite invasion and wound repair. Here, we discuss the possibility that ASM release during lysosomal exocytosis, in response to various forms of stress, may represent a major source of the secretory form of this enzyme.
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Affiliation(s)
- Norma W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
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19
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Snider JM, Luberto C, Hannun YA. Approaches for probing and evaluating mammalian sphingolipid metabolism. Anal Biochem 2019; 575:70-86. [PMID: 30917945 DOI: 10.1016/j.ab.2019.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/22/2019] [Accepted: 03/22/2019] [Indexed: 01/02/2023]
Abstract
Sphingolipid metabolism plays a critical role in regulating processes that control cellular fate. This dynamic pathway can generate and degrade the central players: ceramide, sphingosine and sphingosine-1-phosphate in almost any membrane in the cell, adding an unexpected level of complexity in deciphering signaling events. While in vitro assays have been developed for most enzymes in SL metabolism, these assays are setup for optimal activity conditions and can fail to take into account regulatory components such as compartmentalization, substrate limitations, and binding partners that can affect cellular enzymatic activity. Therefore, many in-cell assays have been developed to derive results that are authentic to the cellular situation which may give context to alteration in SL mass. This review will discuss approaches for utilizing probes for mammalian in-cell assays to interrogate most enzymatic steps central to SL metabolism. The use of inhibitors in conjunction with these probes can verify the specificity of cellular assays as well as provide valuable insight into flux in the SL network. The use of inhibitors specific to each of the central sphingolipid enzymes are also discussed to assist researchers in further interrogation of these pathways.
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Affiliation(s)
- Justin M Snider
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA; The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
| | - Chiara Luberto
- The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Yusuf A Hannun
- Department of Medicine, Stony Brook University, Stony Brook, NY, USA; The Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA; Departments of Biochemistry, Pathology and Pharmacology, Stony Brook University, Stony Brook, NY, USA.
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20
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Novgorodov SA, Voltin JR, Wang W, Tomlinson S, Riley CL, Gudz TI. Acid sphingomyelinase deficiency protects mitochondria and improves function recovery after brain injury. J Lipid Res 2019; 60:609-623. [PMID: 30662008 PMCID: PMC6399498 DOI: 10.1194/jlr.m091132] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/11/2019] [Indexed: 12/12/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of disability worldwide and a prominent risk factor for neurodegenerative diseases. The expansion of nervous tissue damage after the initial trauma involves a multifactorial cascade of events, including excitotoxicity, oxidative stress, inflammation, and deregulation of sphingolipid metabolism that further mitochondrial dysfunction and secondary brain damage. Here, we show that a posttranscriptional activation of an acid sphingomyelinase (ASM), a key enzyme of the sphingolipid recycling pathway, resulted in a selective increase of sphingosine in mitochondria during the first week post-TBI that was accompanied by reduced activity of mitochondrial cytochrome oxidase and activation of the Nod-like receptor protein 3 inflammasome. TBI-induced mitochondrial abnormalities were rescued in the brains of ASM KO mice, which demonstrated improved behavioral deficit recovery compared with WT mice. Furthermore, an elevated autophagy in an ASM-deficient brain at the baseline and during the development of secondary brain injury seems to foster the preservation of mitochondria and brain function after TBI. Of note, ASM deficiency attenuated the early stages of reactive astrogliosis progression in an injured brain. These findings highlight the crucial role of ASM in governing mitochondrial dysfunction and brain-function impairment, emphasizing the importance of sphingolipids in the neuroinflammatory response to TBI.
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Affiliation(s)
- Sergei A Novgorodov
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Joshua R Voltin
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Wenxue Wang
- Microbiology and Immunology Medical University of South Carolina, Charleston, SC 29425
| | - Stephen Tomlinson
- Microbiology and Immunology Medical University of South Carolina, Charleston, SC 29425
| | | | - Tatyana I Gudz
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
- Ralph H. Johnson Veterans Affairs Medical Center Charleston, SC 29401
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Abstract
The kinetoplastid parasite Trypanosoma brucei causes African trypanosomiasis in both humans and animals. Infections place a significant health and economic burden on developing nations in sub-Saharan Africa, but few effective anti-parasitic treatments are currently available. Hence, there is an urgent need to identify new leads for drug development. The T. brucei neutral sphingomyelinase (TbnSMase) was previously established as essential to parasite survival, consequently being identified as a potential drug target. This enzyme may catalyse the single route to sphingolipid catabolism outside the T. brucei lysosome. To obtain new insight into parasite sphingolipid catabolism, the substrate specificity of TbnSMase was investigated using electrospray ionization tandem mass spectrometry (ESI-MS/MS). Recombinant TbnSMase was shown to degrade sphingomyelin, inositol-phosphoceramide and ethanolamine-phosphoceramide sphingolipid substrates, consistent with the sphingolipid complement of the parasites. TbnSMase also catabolized ceramide-1-phosphate, but was inactive towards sphingosine-1-phosphate. The broad-range specificity of this enzyme towards sphingolipid species is a unique feature of TbnSMase. Additionally, ESI-MS/MS analysis revealed previously uncharacterized activity towards lyso-phosphatidylcholine despite the enzyme's inability to degrade phosphatidylcholine. Collectively, these data underline the enzyme's importance in choline homoeostasis and the turnover of sphingolipids in T. brucei.
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Lin G, Lee PT, Chen K, Mao D, Tan KL, Zuo Z, Lin WW, Wang L, Bellen HJ. Phospholipase PLA2G6, a Parkinsonism-Associated Gene, Affects Vps26 and Vps35, Retromer Function, and Ceramide Levels, Similar to α-Synuclein Gain. Cell Metab 2018; 28:605-618.e6. [PMID: 29909971 DOI: 10.1016/j.cmet.2018.05.019] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/23/2018] [Accepted: 05/22/2018] [Indexed: 11/16/2022]
Abstract
Mutations in PLA2G6 (PARK14) cause neurodegenerative disorders in humans, including autosomal recessive neuroaxonal dystrophy and early-onset parkinsonism. We show that loss of iPLA2-VIA, the fly homolog of PLA2G6, reduces lifespan, impairs synaptic transmission, and causes neurodegeneration. Phospholipases typically hydrolyze glycerol phospholipids, but loss of iPLA2-VIA does not affect the phospholipid composition of brain tissue but rather causes an elevation in ceramides. Reducing ceramides with drugs, including myriocin or desipramine, alleviates lysosomal stress and suppresses neurodegeneration. iPLA2-VIA binds the retromer subunits Vps35 and Vps26 and enhances retromer function to promote protein and lipid recycling. Loss of iPLA2-VIA impairs retromer function, leading to a progressive increase in ceramide. This induces a positive feedback loop that affects membrane fluidity and impairs retromer function and neuronal function. Similar defects are observed upon loss of vps26 or vps35 or overexpression of α-synuclein, indicating that these defects may be common in Parkinson disease.
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Affiliation(s)
- Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Dongxue Mao
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Wen-Wen Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Liping Wang
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA.
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23
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Novgorodov SA, Voltin JR, Gooz MA, Li L, Lemasters JJ, Gudz TI. Acid sphingomyelinase promotes mitochondrial dysfunction due to glutamate-induced regulated necrosis. J Lipid Res 2017; 59:312-329. [PMID: 29282302 DOI: 10.1194/jlr.m080374] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/05/2017] [Indexed: 12/11/2022] Open
Abstract
Inhibiting the glutamate/cystine antiporter system xc-, a key antioxidant defense machinery in the CNS, could trigger a novel form of regulated necrotic cell death, ferroptosis. The underlying mechanisms of system xc--dependent cell demise were elucidated using primary oligodendrocytes (OLs) treated with glutamate to block system xc- function. Pharmacological analysis revealed ferroptosis as a major contributing factor to glutamate-initiated OL death. A sphingolipid profile showed elevations of ceramide species and sphingosine that were preventable by inhibiting of an acid sphingomyelinase (ASM) activity. OL survival was enhanced by both downregulating ASM expression and blocking ASM activity. Glutamate-induced ASM activation seems to involve posttranscriptional mechanisms and was associated with a decreased GSH level. Further investigation of the mechanisms of OL response to glutamate revealed enhanced reactive oxygen species production, augmented lipid peroxidation, and opening of the mitochondrial permeability transition pore that were attenuated by hindering ASM. Of note, knocking down sirtuin 3, a deacetylase governing the mitochondrial antioxidant system, reduced OL survival. The data highlight the importance of the mitochondrial compartment in regulated necrotic cell death and accentuate the novel role of ASM in disturbing mitochondrial functions during OL response to glutamate toxicity, which is essential for pathobiology in stroke and traumatic brain injury.
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Affiliation(s)
- Sergei A Novgorodov
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Joshua R Voltin
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Monika A Gooz
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - Li Li
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - John J Lemasters
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - Tatyana I Gudz
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425 .,Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401
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24
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Zhu L, Xiong X, Kim Y, Okada N, Lu F, Zhang H, Sun H. Acid sphingomyelinase is required for cell surface presentation of Met receptor tyrosine kinase in cancer cells. J Cell Sci 2016; 129:4238-4251. [PMID: 27802163 DOI: 10.1242/jcs.191684] [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: 05/03/2016] [Accepted: 09/30/2016] [Indexed: 12/22/2022] Open
Abstract
Receptor tyrosine kinases (RTKs) are embedded in the lipid bilayer of the plasma membrane, but the specific roles of various lipids in cell signaling remain largely uncharacterized. We have previously found that acid sphingomyelinase (ASM; also known as SMPD1) regulates the conserved DAF-2 (the ortholog IGF-1R in mammals) RTK signaling pathway in Caenorhabditis elegans How ASM and its catalytic products, ceramides, control RTK signaling pathways remain unclear. Here, we report that ASM regulates the homeostasis of Met, an RTK that is frequently overexpressed in various cancers. Inactivation of ASM led to a rapid loss of Met from the plasma membrane, reduced Met phosphorylation and activation, and induced Met accumulation in the trans-Golgi network (TGN). However, trafficking of integrin β3 and vesicular stomatitis virus glycoprotein (VSVG) was largely unaffected. Knockdown of syntaxin 6 (STX6) also blocked the Golgi exit of Met. Depletion of either ASM or STX6 led to aberrant trafficking of Met to lysosomes, promoting its degradation. Our studies reveal that ASM and ceramides, together with STX6 and cholesterol, constitute a new regulatory mechanism for the exit of Met from the Golgi during its biosynthetic route, which is used to rapidly replenish and regulate the plasma membrane levels of Met in various cancer cells.
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Affiliation(s)
- Linyu Zhu
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China.,Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
| | - Xiahui Xiong
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
| | - Yongsoon Kim
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
| | - Naomi Okada
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
| | - Fei Lu
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - Hui Zhang
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
| | - Hong Sun
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89135, USA
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25
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Gorelik A, Illes K, Heinz LX, Superti-Furga G, Nagar B. Crystal structure of mammalian acid sphingomyelinase. Nat Commun 2016; 7:12196. [PMID: 27435900 PMCID: PMC4961792 DOI: 10.1038/ncomms12196] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/08/2016] [Indexed: 01/07/2023] Open
Abstract
Acid sphingomyelinase (ASMase, ASM, SMPD1) converts sphingomyelin into ceramide, modulating membrane properties and signal transduction. Inactivating mutations in ASMase cause Niemann-Pick disease, and its inhibition is also beneficial in models of depression and cancer. To gain a better understanding of this critical therapeutic target, we determined crystal structures of mammalian ASMase in various conformations. The catalytic domain adopts a calcineurin-like fold with two zinc ions and a hydrophobic track leading to the active site. Strikingly, the membrane interacting saposin domain assumes either a closed globular conformation independent from the catalytic domain, or an open conformation, which establishes an interface with the catalytic domain essential for activity. Structural mapping of Niemann-Pick mutations reveals that most of them likely destabilize the protein's fold. This study sheds light on the molecular mechanism of ASMase function, and provides a platform for the rational development of ASMase inhibitors and therapeutic use of recombinant ASMase.
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Affiliation(s)
- Alexei Gorelik
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 0B1,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec, Canada H3G 0B1
| | - Katalin Illes
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 0B1,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec, Canada H3G 0B1
| | - Leonhard X. Heinz
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria,Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria,Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Bhushan Nagar
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 0B1,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec, Canada H3G 0B1,
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26
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Gilbert S, Loranger A, Omary MB, Marceau N. Keratin impact on PKCδ- and ASMase-mediated regulation of hepatocyte lipid raft size - implication for FasR-associated apoptosis. J Cell Sci 2016; 129:3262-73. [PMID: 27422101 DOI: 10.1242/jcs.171124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/13/2016] [Indexed: 11/20/2022] Open
Abstract
Keratins are epithelial cell intermediate filament (IF) proteins that are expressed as pairs in a cell-differentiation-regulated manner. Hepatocytes express the keratin 8 and 18 pair (denoted K8/K18) of IFs, and a loss of K8 or K18, as in K8-null mice, leads to degradation of the keratin partner. We have previously reported that a K8/K18 loss in hepatocytes leads to altered cell surface lipid raft distribution and more efficient Fas receptor (FasR, also known as TNFRSF6)-mediated apoptosis. We demonstrate here that the absence of K8 or transgenic expression of the K8 G62C mutant in mouse hepatocytes reduces lipid raft size. Mechanistically, we find that the lipid raft size is dependent on acid sphingomyelinase (ASMase, also known as SMPD1) enzyme activity, which is reduced in absence of K8/K18. Notably, the reduction of ASMase activity appears to be caused by a less efficient redistribution of surface membrane PKCδ toward lysosomes. Moreover, we delineate the lipid raft volume range that is required for an optimal FasR-mediated apoptosis. Hence, K8/K18-dependent PKCδ- and ASMase-mediated modulation of lipid raft size can explain the more prominent FasR-mediated signaling resulting from K8/K18 loss. The fine-tuning of ASMase-mediated regulation of lipid rafts might provide a therapeutic target for death-receptor-related liver diseases.
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Affiliation(s)
- Stéphane Gilbert
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
| | - Anne Loranger
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
| | - M Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Normand Marceau
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
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27
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Xiong ZJ, Huang J, Poda G, Pomès R, Privé GG. Structure of Human Acid Sphingomyelinase Reveals the Role of the Saposin Domain in Activating Substrate Hydrolysis. J Mol Biol 2016; 428:3026-42. [PMID: 27349982 DOI: 10.1016/j.jmb.2016.06.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 11/29/2022]
Abstract
Acid sphingomyelinase (ASM) is a lysosomal phosphodiesterase that catalyzes the hydrolysis of sphingomyelin to produce ceramide and phosphocholine. While other lysosomal sphingolipid hydrolases require a saposin activator protein for full activity, the ASM polypeptide incorporates a built-in N-terminal saposin domain and does not require an external activator protein. Here, we report the crystal structure of human ASM and describe the organization of the three main regions of the enzyme: the N-terminal saposin domain, the proline-rich connector, and the catalytic domain. The saposin domain is tightly associated along an edge of the large, bowl-shaped catalytic domain and adopts an open form that exposes a hydrophobic concave surface approximately 30Å from the catalytic center. The calculated electrostatic potential of the enzyme is electropositive at the acidic pH of the lysosome, consistent with the strict requirement for the presence of acidic lipids in target membranes. Docking studies indicate that sphingomyelin binds with the ceramide-phosphate group positioned at the binuclear zinc center and molecular dynamic simulations indicate that the intrinsic flexibility of the saposin domain is important for monomer-dimer exchange and for membrane interactions. Overall, ASM uses a combination of electrostatic and hydrophobic interactions to cause local disruptions of target bilayers in order to bring the lipid headgroup to the catalytic center in a membrane-bound reaction.
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Affiliation(s)
- Zi-Jian Xiong
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jingjing Huang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Gennady Poda
- Drug Discovery, Ontario Institute for Cancer Research, Toronto, Ontario, Canada; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Régis Pomès
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Molecular Structure and Function, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gilbert G Privé
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
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28
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Adada M, Luberto C, Canals D. Inhibitors of the sphingomyelin cycle: Sphingomyelin synthases and sphingomyelinases. Chem Phys Lipids 2016. [DOI: 10.1016/j.chemphyslip.2015.07.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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29
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Castro-Gomes T, Corrotte M, Tam C, Andrews NW. Plasma Membrane Repair Is Regulated Extracellularly by Proteases Released from Lysosomes. PLoS One 2016; 11:e0152583. [PMID: 27028538 PMCID: PMC4814109 DOI: 10.1371/journal.pone.0152583] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 12/28/2022] Open
Abstract
Eukaryotic cells rapidly repair wounds on their plasma membrane. Resealing is Ca2+-dependent, and involves exocytosis of lysosomes followed by massive endocytosis. Extracellular activity of the lysosomal enzyme acid sphingomyelinase was previously shown to promote endocytosis and wound removal. However, whether lysosomal proteases released during cell injury participate in resealing is unknown. Here we show that lysosomal proteases regulate plasma membrane repair. Extracellular proteolysis is detected shortly after cell wounding, and inhibition of this process blocks repair. Conversely, surface protein degradation facilitates plasma membrane resealing. The abundant lysosomal cysteine proteases cathepsin B and L, known to proteolytically remodel the extracellular matrix, are rapidly released upon cell injury and are required for efficient plasma membrane repair. In contrast, inhibition of aspartyl proteases or RNAi-mediated silencing of the lysosomal aspartyl protease cathepsin D enhances resealing, an effect associated with the accumulation of active acid sphingomyelinase on the cell surface. Thus, secreted lysosomal cysteine proteases may promote repair by facilitating membrane access of lysosomal acid sphingomyelinase, which promotes wound removal and is subsequently downregulated extracellularly by a process involving cathepsin D.
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Affiliation(s)
- Thiago Castro-Gomes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Matthias Corrotte
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Christina Tam
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, 20742, United States of America
- * E-mail:
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30
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Melland-Smith M, Ermini L, Chauvin S, Craig-Barnes H, Tagliaferro A, Todros T, Post M, Caniggia I. Disruption of sphingolipid metabolism augments ceramide-induced autophagy in preeclampsia. Autophagy 2016; 11:653-69. [PMID: 25853898 DOI: 10.1080/15548627.2015.1034414] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Bioactive sphingolipids including ceramides are involved in a variety of pathophysiological processes by regulating cell death and survival. The objective of the current study was to examine ceramide metabolism in preeclampsia, a serious disorder of pregnancy characterized by oxidative stress, and increased trophoblast cell death and autophagy. Maternal circulating and placental ceramide levels quantified by tandem mass spectrometry were elevated in pregnancies complicated by preeclampsia. Placental ceramides were elevated due to greater de novo synthesis via high serine palmitoyltransferase activity and reduced lysosomal breakdown via diminished ASAH1 expression caused by TGFB3-induced E2F4 transcriptional repression. SMPD1 activity was reduced; hence, sphingomyelin degradation by SMPD1 did not contribute to elevated ceramide levels in preeclampsia. Oxidative stress triggered similar changes in ceramide levels and acid hydrolase expression in villous explants and trophoblast cells. MALDI-imaging mass spectrometry localized the ceramide increases to the trophophoblast layers and syncytial knots of placentae from pregnancies complicated by preeclampsia. ASAH1 inhibition or ceramide treatment induced autophagy in human trophoblast cells via a shift of the BOK-MCL1 rheostat toward prodeath BOK. Pharmacological inhibition of ASAH1 activity in pregnant mice resulted in increased placental ceramide content, abnormal placentation, reduced fetal growth, and increased autophagy via a similar shift in the BOK-MCL1 system. Our results reveal that oxidative stress-induced reduction of lysosomal hydrolase activities in combination with elevated de novo synthesis leads to ceramide overload, resulting in increased trophoblast cell autophagy, and typifies preeclampsia as a sphingolipid storage disorder.
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Key Words
- 2-OE, 2-oleoylethanolamine
- 3-KDS, 3-keto dihydrosphingosine
- 3-MA, 3-methyladenine
- ACTB, actin β
- ASAH1, N-acylsphingosine amidohydrolase (acid ceramidase) 1
- BECN1, Beclin 1, autophagy related
- BOK
- BOK, BCL2-related ovarian killer
- BafA1, bafilomycin A1
- CANX, calnexin
- CASP3 (caspase 3, apoptosis-related cysteine peptidase)
- CERs, ceramides
- CT, cytotrophoblast cells
- D-NMAPPD, N-[(1R,2R)-2-hydroxyl-1-(hydroxyL-methyl)-2-(4-nitrophenyl) ethyl]-tetradecanamide
- DHCer, dihydro-ceramide
- E2F4, E2F transcription factor 4, p107/p130-binding
- HIF1A, hypoxia inducible factor 1, α, subunit (basic helix-loop-helix transcription factor)
- LAMP1, lysosomal-associated membrane protein 1
- LC-MS/MS, liquid chromatography-tandem mass spectrometry
- LC3B-II, cleaved and lipidated form of microtubule-associated protein 1 light chain 3 β (MAP1LC3B/LC3B)
- MALDI-MS, matrix-assisted laser desorption/ionization-mass spectrometry
- MCL1
- MCL1, myeloid cell leukemia 1
- PE, preeclampsia
- PTC, preterm control
- S1P, sphingosine-1-phosphate
- SM, sphingomyelin
- SMPD1, sphingomyelin phosphodiesterase 1, acid lysosomal (acid sphingomyelinase)
- SNP, sodium nitroprusside (III)
- SPH, sphingosine
- SPT, serine palmitoyltransferase
- SQSTM1/p62, sequestosome 1
- ST, syncytium/syncytiotrophoblast cells
- Sa, sphinganine
- TC, term control
- TGFB, transforming growth factor β
- autophagy
- oxidative stress
- placenta
- preeclampsia
- siRNA, small-interfering ribonucleic acid
- sphingolipid metabolism
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Affiliation(s)
- Megan Melland-Smith
- a The Lunenfeld-Tanenbaum Research Institute; Mount Sinai Hospital ; Toronto , ON Canada
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31
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Abstract
Glycosphingolipids (GSLs) are a family of bioactive lipids that in addition to their role in the regulation of structural properties of membrane bilayers have emerged as crucial players in many biological processes and signal transduction pathways. Rather than being uniformly distributed within membrane bilayers, GSLs are localized in selective domains called lipid rafts where many signaling platforms operate. One of the most important functions of GSLs, particularly ceramide, is their ability to regulate cell death pathways and hence cell fate. This complex role is accomplished by the ability of GSLs to act in distinct subcellular strategic centers, such as mitochondria, endoplasmic reticulum (ER) or lysosomes to mediate apoptosis, ER stress, autophagy, lysosomal membrane permeabilization and necroptosis. Hence better understanding the role of GSLs in cell death may be of relevance for a number of pathological processes and diseases, including neurodegeneration, metabolic liver diseases and cancer.
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32
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Zampieri S, Filocamo M, Pianta A, Lualdi S, Gort L, Coll MJ, Sinnott R, Geberhiwot T, Bembi B, Dardis A. SMPD1 Mutation Update: Database and Comprehensive Analysis of Published and Novel Variants. Hum Mutat 2015; 37:139-47. [PMID: 26499107 DOI: 10.1002/humu.22923] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 10/12/2015] [Indexed: 01/15/2023]
Abstract
Niemann-Pick Types A and B (NPA/B) diseases are autosomal recessive lysosomal storage disorders caused by the deficient activity of acid sphingomyelinase (ASM) because of the mutations in the SMPD1 gene. Here, we provide a comprehensive updated review of already reported and newly identified SMPD1 variants. Among them, 185 have been found in NPA/B patients. Disease-causing variants are equally distributed along the SMPD1 gene; most of them are missense (65.4%) or frameshift (19%) mutations. The most frequently reported mutation worldwide is the p.R610del, clearly associated with an attenuated NP disease type B phenotype. The available information about the impact of 52 SMPD1 variants on ASM mRNA and/or enzymatic activity has been collected and whenever possible, phenotype/genotype correlations were established. In addition, we created a locus-specific database easily accessible at http://www.inpdr.org/genes that catalogs the 417 SMPD1 variants reported to date and provides data on their in silico predicted effects on ASM protein function or mRNA splicing. The information reviewed in this article, providing new insights into the genotype/phenotype correlation, is extremely valuable to facilitate diagnosis and genetic counseling of families affected by NPA/B.
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Affiliation(s)
- Stefania Zampieri
- Regional Coordinator Centre for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Mirella Filocamo
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Annalisa Pianta
- Regional Coordinator Centre for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Susanna Lualdi
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Laura Gort
- Sección Errores Congénitos del Metabolismo-IBC, Serv Bioquímica y Genética Molecular, Hospital Clínic; IDIBAPS; CIBERER, Barcelona, Spain
| | - Maria Jose Coll
- Sección Errores Congénitos del Metabolismo-IBC, Serv Bioquímica y Genética Molecular, Hospital Clínic; IDIBAPS; CIBERER, Barcelona, Spain
| | - Richard Sinnott
- Department of Computing and Information Systems, University of Melbourne, Melbourne, Australia
| | | | - Bruno Bembi
- Regional Coordinator Centre for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Andrea Dardis
- Regional Coordinator Centre for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
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Mevalonate inhibits acid sphingomyelinase activity, increases sphingomyelin levels and inhibits cell proliferation of HepG2 and Caco-2 cells. Lipids Health Dis 2015; 14:130. [PMID: 26493087 PMCID: PMC4618740 DOI: 10.1186/s12944-015-0137-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 10/15/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Sphingomyelin (SM) and cholesterol are two types of lipid closely related biophysically. Treating the cells with exogenous sphingomyelinase (SMase) induces trafficking of cholesterol from membrane to intracellular pools and inhibition of cholesterol synthesis. In the present work, we address a question whether increased cholesterol synthesis affects hydrolysis of SM by endogenous SMases. METHODS Both HepG2 and Caco-2 cells were incubated with mevalonate. The SMase activity was determined and its mRNA examined by qPCR. The cellular levels of cholesterol, SM, and phosphatidylcholine (PC) were determined and cell proliferation rate assayed. RESULTS We found that mevalonate dose-dependently decreased acid but not neutral SMase activity in both HepG2 and Caco-2 cells with HepG2 cells being more sensitive to mevalonate. Kinetic examination in HepG2 cells revealed that acid SMase activity was increasing with cell proliferation, and such an increase was reversed by mevalonate treatment. Acid SMase mRNA was not significantly decreased and Western blot showed signs of proteolysis of acid SMase by mevalonate. After mevalonate treatment, the levels of cholesterol were significantly increased associated with increases in SM and PC. The cell growth was retarded by mevalonate and the effect was more obvious in HepG2 cells than in Caco-2 cells. CONCLUSION Mevalonate can trigger a mechanism to enhance SM levels by inhibition of acid SMase. The effect may ensure the coordinate changes of SM and cholesterol in the cells. Mevalonate also affects cell growth with mechanism required further characterization.
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Gulbins E, Walter S, Becker KA, Halmer R, Liu Y, Reichel M, Edwards MJ, Müller CP, Fassbender K, Kornhuber J. A central role for the acid sphingomyelinase/ceramide system in neurogenesis and major depression. J Neurochem 2015; 134:183-92. [DOI: 10.1111/jnc.13145] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 03/15/2015] [Accepted: 04/09/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Erich Gulbins
- Department of Surgery; University of Cincinnati; Cincinnati Ohio USA
- Department of Molecular Biology; University of Duisburg-Essen; Essen Germany
| | - Silke Walter
- Department of Neurology; University Hospital of the Saarland; Homburg/Saar Germany
| | - Katrin Anne Becker
- Department of Molecular Biology; University of Duisburg-Essen; Essen Germany
| | - Ramona Halmer
- Department of Neurology; University Hospital of the Saarland; Homburg/Saar Germany
| | - Yang Liu
- Department of Neurology; University Hospital of the Saarland; Homburg/Saar Germany
| | - Martin Reichel
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen; Erlangen Germany
| | | | - Christian P. Müller
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen; Erlangen Germany
| | - Klaus Fassbender
- Department of Neurology; University Hospital of the Saarland; Homburg/Saar Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy; Friedrich-Alexander-University of Erlangen; Erlangen Germany
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Fonteh AN, Ormseth C, Chiang J, Cipolla M, Arakaki X, Harrington MG. Sphingolipid metabolism correlates with cerebrospinal fluid Beta amyloid levels in Alzheimer's disease. PLoS One 2015; 10:e0125597. [PMID: 25938590 PMCID: PMC4418746 DOI: 10.1371/journal.pone.0125597] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 03/24/2015] [Indexed: 12/14/2022] Open
Abstract
Sphingolipids are important in many brain functions but their role in Alzheimer’s disease (AD) is not completely defined. A major limit is availability of fresh brain tissue with defined AD pathology. The discovery that cerebrospinal fluid (CSF) contains abundant nanoparticles that include synaptic vesicles and large dense core vesicles offer an accessible sample to study these organelles, while the supernatant fluid allows study of brain interstitial metabolism. Our objective was to characterize sphingolipids in nanoparticles representative of membrane vesicle metabolism, and in supernatant fluid representative of interstitial metabolism from study participants with varying levels of cognitive dysfunction. We recently described the recruitment, diagnosis, and CSF collection from cognitively normal or impaired study participants. Using liquid chromatography tandem mass spectrometry, we report that cognitively normal participants had measureable levels of sphingomyelin, ceramide, and dihydroceramide species, but that their distribution differed between nanoparticles and supernatant fluid, and further differed in those with cognitive impairment. In CSF from AD compared with cognitively normal participants: a) total sphingomyelin levels were lower in nanoparticles and supernatant fluid; b) levels of ceramide species were lower in nanoparticles and higher in supernatant fluid; c) three sphingomyelin species were reduced in the nanoparticle fraction. Moreover, three sphingomyelin species in the nanoparticle fraction were lower in mild cognitive impairment compared with cognitively normal participants. The activity of acid, but not neutral sphingomyelinase was significantly reduced in the CSF from AD participants. The reduction in acid sphingomylinase in CSF from AD participants was independent of depression and psychotropic medications. Acid sphingomyelinase activity positively correlated with amyloid β42 concentration in CSF from cognitively normal but not impaired participants. In dementia, altered sphingolipid metabolism, decreased acid sphingomyelinase activity and its lost association with CSF amyloid β42 concentration, underscores the potential of sphingolipids as disease biomarkers, and acid sphingomyelinase as a target for AD diagnosis and/or treatment.
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Affiliation(s)
- Alfred N. Fonteh
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
- * E-mail:
| | - Cora Ormseth
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
| | - Jiarong Chiang
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
| | - Matthew Cipolla
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
| | - Xianghong Arakaki
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
| | - Michael G. Harrington
- Molecular Neurology Program, Huntington Medical Research Institutes, 99 N El Molino Ave, Pasadena, California, United Sates of America
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Oninla VO, Breiden B, Babalola JO, Sandhoff K. Acid sphingomyelinase activity is regulated by membrane lipids and facilitates cholesterol transfer by NPC2. J Lipid Res 2014; 55:2606-19. [PMID: 25339683 PMCID: PMC4242453 DOI: 10.1194/jlr.m054528] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/15/2015] [Indexed: 11/20/2022] Open
Abstract
During endocytosis, membrane components move to intraluminal vesicles of the endolysosomal compartment for digestion. At the late endosomes, cholesterol is sorted out mainly by two sterol-binding proteins, Niemann-Pick protein type C (NPC)1 and NPC2. To study the NPC2-mediated intervesicular cholesterol transfer, we developed a liposomal assay system. (Abdul-Hammed, M., B. Breiden, M. A. Adebayo, J. O. Babalola, G. Schwarzmann, and K. Sandhoff. 2010. Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion. J. Lipid Res. 51: 1747-1760.) Anionic lipids stimulate cholesterol transfer between liposomes while SM inhibits it, even in the presence of anionic bis(monoacylglycero)phosphate (BMP). Preincubation of vesicles containing SM with acid sphingomyelinase (ASM) (SM phosphodiesterase, EC 3.1.4.12) results in hydrolysis of SM to ceramide (Cer), which enhances cholesterol transfer. Besides SM, ASM also cleaves liposomal phosphatidylcholine. Anionic phospholipids derived from the plasma membrane (phosphatidylglycerol and phosphatidic acid) stimulate SM and phosphatidylcholine hydrolysis by ASM more effectively than BMP, which is generated during endocytosis. ASM-mediated hydrolysis of liposomal SM was also stimulated by incorporation of diacylglycerol (DAG), Cer, and free fatty acids into the liposomal membranes. Conversely, phosphatidylcholine hydrolysis was inhibited by incorporation of cholesterol, Cer, DAG, monoacylglycerol, and fatty acids. Our data suggest that SM degradation by ASM is required for physiological secretion of cholesterol from the late endosomal compartment, and is a key regulator of endolysosomal lipid digestion.
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Affiliation(s)
- Vincent O. Oninla
- LIMES Institute, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, D-53121 Bonn, Germany
- Department of Chemistry, University of Ibadan, Ibadan, Nigeria
| | - Bernadette Breiden
- LIMES Institute, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, D-53121 Bonn, Germany
| | | | - Konrad Sandhoff
- LIMES Institute, Membrane Biology and Lipid Biochemistry Unit, Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, D-53121 Bonn, Germany
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Zhu H, Yoshimoto T, Yamashima T. Heat shock protein 70.1 (Hsp70.1) affects neuronal cell fate by regulating lysosomal acid sphingomyelinase. J Biol Chem 2014; 289:27432-43. [PMID: 25074941 PMCID: PMC4183783 DOI: 10.1074/jbc.m114.560334] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/18/2014] [Indexed: 12/17/2022] Open
Abstract
The inducible expression of heat shock protein 70.1 (Hsp70.1) plays cytoprotective roles in its molecular chaperone function. Binding of Hsp70 to an endolysosomal phospholipid, bis(monoacylglycero)phosphate (BMP), has been recently shown to stabilize lysosomal membranes by enhancing acid sphingomyelinase (ASM) activity in cancer cells. Using the monkey experimental paradigm, we have reported that calpain-mediated cleavage of oxidized Hsp70.1 causes neurodegeneration in the hippocampal cornu ammonis 1 (CA1), whereas expression of Hsp70.1 in the motor cortex without calpain activation contributes to neuroprotection. However, the molecular mechanisms of the lysosomal destabilization/stabilization determining neuronal cell fate have not been elucidated. To elucidate whether regulation of lysosomal ASM could affect the neuronal fate, we analyzed Hsp70.1-BMP binding and ASM activity by comparing the motor cortex and the CA1. We show that Hsp70.1 being localized at the lysosomal membrane, lysosomal lipid BMP levels, and the lipid binding domain of Hsp70.1 are crucial for Hsp70.1-BMP binding. In the postischemic motor cortex, Hsp70.1 being localized at the lysosomal membrane could bind to BMP without calpain activation and decreased BMP levels, resulting in increasing ASM activity and lysosomal stability. However, in the postischemic CA1, calpain activation and a concomitant decrease in the lysosomal membrane localization of Hsp70.1 and BMP levels may diminish Hsp70.1-BMP binding, resulting in decreased ASM activity and lysosomal rupture with leakage of cathepsin B into the cytosol. A TUNEL assay revealed the differential neuronal vulnerability between the CA1 and the motor cortex. These results suggest that regulation of ASM activation in vivo by Hsp70.1-BMP affects lysosomal stability and neuronal survival or death after ischemia/reperfusion.
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Affiliation(s)
- Hong Zhu
- From the Departments of Restorative Neurosurgery, Molecular Pharmacology, and
| | | | - Tetsumori Yamashima
- From the Departments of Restorative Neurosurgery, Psychiatry and Neurobiology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, Japan
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Tsunemi T, Krainc D. Zn²⁺ dyshomeostasis caused by loss of ATP13A2/PARK9 leads to lysosomal dysfunction and alpha-synuclein accumulation. Hum Mol Genet 2013; 23:2791-801. [PMID: 24334770 DOI: 10.1093/hmg/ddt572] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutations in ATP13A2 (PARK9) cause Kufor-Rakeb syndrome (KRS) characterized by juvenile-onset parkinsonism, pyramidal signs and dementia. PARK9 belongs to type 5 P-type ATPase with its putative function as a cation transporter. Loss of PARK9 leads to lysosomal dysfunction and subsequent α-synuclein (α-Syn) accumulation. However, the mechanistic link between PARK9 and lysosomal dysfunction remains unclear. Here, we found that patient fibroblasts expressing mutant PARK9 or primary neurons with silenced PARK9 exhibited increased sensitivity to extracellular zinc (Zn(2+)). This effect was rescued with the Zn(2+) chelators clioquinol or TPEN. PARK9-deficient cells showed decreased lysosomal sequestration of Zn(2+) and increased expression of zinc transporters. Importantly, increased concentrations of Zn(2+) (Zn(2+) stress) resulted in lysosomal dysfunction that was partially restored by expression of wild-type PARK9. Zn(2+) stress also caused increased expression of α-Syn and consequently decreased activity of the lysosomal enzyme glucocerebrosidase. Together, these data suggest that PARK9 loss of function leads to dyshomeostasis of intracellular Zn(2+) that in turn contributes to lysosomal dysfunction and accumulation of α-Syn. It will be of interest to examine whether therapeutic lowering of zinc may prove beneficial for patients with KRS.
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Affiliation(s)
- Taiji Tsunemi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, MassGeneral Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
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Fernandez A, Matias N, Fucho R, Ribas V, Von Montfort C, Nuño N, Baulies A, Martinez L, Tarrats N, Mari M, Colell A, Morales A, Dubuquoy L, Mathurin P, Bataller R, Caballeria J, Elena M, Balsinde J, Kaplowitz N, Garcia-Ruiz C, Fernandez-Checa JC. ASMase is required for chronic alcohol induced hepatic endoplasmic reticulum stress and mitochondrial cholesterol loading. J Hepatol 2013; 59:805-13. [PMID: 23707365 PMCID: PMC3779525 DOI: 10.1016/j.jhep.2013.05.023] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 05/07/2013] [Accepted: 05/13/2013] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS The pathogenesis of alcohol-induced liver disease (ALD) is poorly understood. Here, we examined the role of acid sphingomyelinase (ASMase) in alcohol induced hepatic endoplasmic reticulum (ER) stress, a key mechanism of ALD. METHODS We examined ER stress, lipogenesis, hyperhomocysteinemia, mitochondrial cholesterol (mChol) trafficking and susceptibility to LPS and concanavalin-A in ASMase(-)(/-) mice fed alcohol. RESULTS Alcohol feeding increased SREBP-1c, DGAT-2, and FAS mRNA in ASMase(+/+) but not in ASMase(-/-) mice. Compared to ASMase(+/+) mice, ASMase(-/-) mice exhibited decreased expression of ER stress markers induced by alcohol, but the level of tunicamycin-mediated upregulation of ER stress markers and steatosis was similar in both types of mice. The increase in homocysteine levels induced by alcohol feeding was comparable in both ASMase(+/+) and ASMase(-/-) mice. Exogenous ASMase, but not neutral SMase, induced ER stress by perturbing ER Ca(2+) homeostasis. Moreover, alcohol-induced mChol loading and StARD1 overexpression were blunted in ASMase(-/-) mice. Tunicamycin upregulated StARD1 expression and this outcome was abrogated by tauroursodeoxycholic acid. Alcohol-induced liver injury and sensitization to LPS and concanavalin-A were prevented in ASMase(-/-) mice. These effects were reproduced in alcohol-fed TNFR1/R2(-/-) mice. Moreover, ASMase does not impair hepatic regeneration following partial hepatectomy. Of relevance, liver samples from patients with alcoholic hepatitis exhibited increased expression of ASMase, StARD1, and ER stress markers. CONCLUSIONS Our data indicate that ASMase is critical for alcohol-induced ER stress, and provide a rationale for further clinical investigation in ALD.
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Affiliation(s)
- Anna Fernandez
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Núria Matias
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Raquel Fucho
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Vicente Ribas
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Claudia Von Montfort
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Natalia Nuño
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Anna Baulies
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Laura Martinez
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Núria Tarrats
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Montserrat Mari
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Anna Colell
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Albert Morales
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Laurent Dubuquoy
- Université Lille Nord de France, and Service des Maladies de l'Appareil Digestif, Hôpital Huriez, Lille, France; Unité 995, Institut National de la Santé et de la Recherche Médicale, Lille, France
| | - Philippe Mathurin
- Université Lille Nord de France, and Service des Maladies de l'Appareil Digestif, Hôpital Huriez, Lille, France; Unité 995, Institut National de la Santé et de la Recherche Médicale, Lille, France
| | - Ramón Bataller
- Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Joan Caballeria
- Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | | | - Jesus Balsinde
- Institut of Molecular Biology and Genetics, CSIC-CIBERDEM, Valladolid, Spain
| | - Neil Kaplowitz
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033
| | - Carmen Garcia-Ruiz
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain,Carmen Garcia-Ruiz and Jose C Fernandez-Checa share senior authorship. Correspondence addressed to Jose C Fernandez-Checa,
| | - Jose C. Fernandez-Checa
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain,Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033,Carmen Garcia-Ruiz and Jose C Fernandez-Checa share senior authorship. Correspondence addressed to Jose C Fernandez-Checa,
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Abstract
The enzyme acid sphingomyelinase catalyzes the hydrolysis of sphingomyelin to ceramide. The importance of the enzyme for cell functions was first recognized in Niemann-Pick disease type A and B, the genetic disorders with a massive accumulation of sphingomyelin in many organs. Studies in the last years demonstrated that the enzyme also has an important role in cell signalling. Thus, the acid sphingomyelinase has a central function for the re-organization of molecules within the cell upon stimulation and thereby for the response of cells to stress and the induction of cell death but also proliferation and differentiation. Here, we discuss the current state of the art of the structure, regulation, and function of the acid sphingomyelinase.
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Affiliation(s)
- Brian Henry
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
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Qin J, Dawson G. Evidence for coordination of lysosomal (ASMase) and plasma membrane (NSMase2) forms of sphingomyelinase from mutant mice. FEBS Lett 2012; 586:4002-9. [PMID: 23046545 PMCID: PMC3498985 DOI: 10.1016/j.febslet.2012.09.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 01/01/2023]
Abstract
NSMase2 is associated to the plasma membrane, whereas ASMase is predominantly lysosomal; both hydrolyze sphingomyelin (SM) to ceramide and phosphocholine. Although SM accumulated in both ASMase(-/-) and fro/fro (NSMase2(-/-)) fibroblasts, the reduction of ceramides was more dramatic in fro/fro cells. ASMase mRNA, protein and enzyme activity were substantially elevated in fro/fro fibroblasts. In contrast, NSMase2 activity was unaffected in ASMase(-/-) fibroblasts. ASMase(-/-) cells showed normal cell cycling whereas fro/fro cells grew slowly and were arrested in G1/G0 and could be corrected by transfection with smpd3 gene. This suggests two distinct subcellular pathways for SM catabolism with distinct functions.
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Affiliation(s)
- Jingdong Qin
- Department of Pediatrics, University of Chicago, Chicago, Illinois 60637
| | - Glyn Dawson
- Department of Pediatrics, University of Chicago, Chicago, Illinois 60637
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637
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Shaw BF, Schneider GF, Whitesides GM. Effect of surfactant hydrophobicity on the pathway for unfolding of ubiquitin. J Am Chem Soc 2012; 134:18739-45. [PMID: 23095057 DOI: 10.1021/ja3079863] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This paper describes the interaction between ubiquitin (UBI) and three sodium n-alkyl sulfates (SC(n)S) that have the same charge (Z = -1) but different hydrophobicity (n = 10, 12, or 14). Increasing the hydrophobicity of the n-alkyl sulfate resulted in (i) an increase in the number of distinct intermediates (that is, complexes of UBI and surfactant) that form along the pathway of unfolding, (ii) a decrease in the minimum concentrations of surfactant at which intermediates begin to form (i.e., a more negative ΔG(binding) of surfactant for UBI), and (iii) an increase in the number of surfactant molecules bound to UBI in each intermediate or complex. These results demonstrate that small changes in the hydrophobicity of a surfactant can significantly alter the binding interactions with a folded or unfolded cytosolic protein.
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Affiliation(s)
- Bryan F Shaw
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
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Ebolavirus requires acid sphingomyelinase activity and plasma membrane sphingomyelin for infection. J Virol 2012; 86:7473-83. [PMID: 22573858 DOI: 10.1128/jvi.00136-12] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Acid sphingomyelinase (ASMase) converts the lipid sphingomyelin (SM) to phosphocholine and ceramide and has optimum activity at acidic pH. Normally, ASMase is located in lysosomes and endosomes, but membrane damage or the interaction with some bacterial and viral pathogens can trigger its recruitment to the plasma membrane. Rhinovirus and measles viruses each require ASMase activity during early stages of infection. Both sphingomyelin and ceramide are important components of lipid rafts and are potent signaling molecules. Each plays roles in mediating macropinocytosis, which has been shown to be important for ebolavirus (EBOV) infection. Here, we investigated the role of ASMase and its substrate, SM, in EBOV infection. The work was performed at biosafety level 4 with wild-type virus with specificity and mechanistic analysis performed using virus pseudotypes and virus-like particles. We found that virus particles strongly associate with the SM-rich regions of the cell membrane and depletion of SM reduces EBOV infection. ASM-specific drugs and multiple small interfering RNAs strongly inhibit the infection by EBOV and EBOV glycoprotein pseudotyped viruses but not by the pseudotypes bearing the glycoprotein of vesicular stomatitis virus. Interestingly, the binding of virus-like particles to cells is strongly associated with surface-localized ASMase as well as SM-enriched sites. Our work suggests that ASMase activity and SM presence are necessary for efficient infection of cells by EBOV. The inhibition of this pathway may provide new avenues for drug treatment.
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Qin J, Berdyshev E, Poirer C, Schwartz NB, Dawson G. Neutral sphingomyelinase 2 deficiency increases hyaluronan synthesis by up-regulation of Hyaluronan synthase 2 through decreased ceramide production and activation of Akt. J Biol Chem 2012; 287:13620-32. [PMID: 22383528 PMCID: PMC3340193 DOI: 10.1074/jbc.m111.304857] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 02/21/2012] [Indexed: 02/06/2023] Open
Abstract
Fibroblasts from the fro/fro mouse, with a deletion in the Smpd3 gene coding for the active site of neutral sphingomyelinase 2 (NSMase2), secreted increased amounts of hyaluronan (HA). This was reversed by transfection with the Smpd3 gene, suggesting a connection between sphingolipid and glycosaminoglycan metabolism. The deficiency of NSMase2 resulted in storage of sphingomyelin (SM) and cholesterol with a 50% reduction in ceramides (Cer). RT-PCR and Western blot analysis showed that increased HA secretion resulted from increased hyaluronan synthase 2 (HAS2) activity localized to sphingolipid-enriched lipid rafts. Although cholesterol levels were also elevated in lipid rafts from mouse fibroblasts deficient in lysosomal acid SMase activity (deletion of the Smpd1(-/-) gene), there was no increase in HA secretion. We then showed that in fro/fro fibroblasts, the reduced ceramide was associated with decreased phosphorylation of protein phosphatase 2A (PP2A) and increased phosphorylation of its substrate Akt-p, together with PI3K, PDK1, mTOR (mammalian target of rapamycin), and p70S6K, although PTEN was unaffected. Exogenous ceramide, as well as inhibitors of Akt (Akt inhibitor VIII), PI 3-kinase (LY294002 and wortmannin), and mTOR (rapamycin) reduced secretion of HA, whereas the NSMase2 inhibitor GW4869 increased HA synthesis and secretion. We propose that NSMase2/Cer are the key mediators of the regulation of HA synthesis, via microdomains and the Akt/mTOR pathway.
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Affiliation(s)
| | - Evgeny Berdyshev
- the Department of Medicine, Institute for Personalized Respiratory Medicine, University of Illinois, Chicago, Illinois 60612, and
| | - Christophe Poirer
- the Georgia Health Sciences University, Vascular Biology Center, Athens, Georgia 30912
| | - Nancy B. Schwartz
- From the Departments of Pediatrics and
- Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637
| | - Glyn Dawson
- From the Departments of Pediatrics and
- Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637
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45
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Moles A, Tarrats N, Fernández-Checa JC, Marí M. Cathepsin B overexpression due to acid sphingomyelinase ablation promotes liver fibrosis in Niemann-Pick disease. J Biol Chem 2011; 287:1178-88. [PMID: 22102288 DOI: 10.1074/jbc.m111.272393] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Niemann-Pick disease (NPD) is a lysosomal storage disease caused by the loss of acid sphingomyelinase (ASMase) that features neurodegeneration and liver disease. Because ASMase-knock-out mice models NPD and our previous findings revealed that ASMase activates cathepsins B/D (CtsB/D), our aim was to investigate the expression and processing of CtsB/D in hepatic stellate cells (HSCs) from ASMase-null mice and their role in liver fibrosis. Surprisingly, HSCs from ASMase-knock-out mice exhibit increased basal level and activity of CtsB as well as its in vitro processing in culture, paralleling the enhanced expression of fibrogenic markers α-smooth muscle actin (α-SMA), TGF-β, and pro-collagen-α1(I) (Col1A1). Moreover, pharmacological inhibition of CtsB blunted the expression of α-SMA and Col1A1 and proliferation of HSCs from ASMase-knock-out mice. Consistent with the enhanced activation of CtsB in HSCs from ASMase-null mice, the in vivo liver fibrosis induced by chronic treatment with CCl(4) increased in ASMase-null compared with wild-type mice, an effect that was reduced upon CtsB inhibition. In addition to liver, the enhanced proteolytic processing of CtsB was also observed in brain and lung of ASMase-knock-out mice, suggesting that the overexpression of CtsB may underlie the phenotype of NPD. Thus, these findings reveal a functional relationship between ASMase and CtsB and that the ablation of ASMase leads to the enhanced processing and activation of CtsB. Therefore, targeting CtsB may be of relevance in the treatment of liver fibrosis in patients with NPD.
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Affiliation(s)
- Anna Moles
- Liver Unit-Hospital Clínic, Centro de Investigación Biomédica en Red en el Área Temática de Entermedades Hepáticas y Digestivas, and Department of Cell Death and Proliferation, Instituto de Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas, 08036 Barcelona, Spain
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46
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Reichel M, Beck J, Mühle C, Rotter A, Bleich S, Gulbins E, Kornhuber J. Activity of Secretory Sphingomyelinase Is Increased in Plasma of Alcohol-Dependent Patients. Alcohol Clin Exp Res 2011; 35:1852-9. [DOI: 10.1111/j.1530-0277.2011.01529.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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