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Yi J, Qi B, Yin J, Li R, Chen X, Hu J, Li G, Zhang S, Zhang Y, Yang M. Molecular basis for the catalytic mechanism of human neutral sphingomyelinases 1 (hSMPD2). Nat Commun 2023; 14:7755. [PMID: 38012235 PMCID: PMC10682184 DOI: 10.1038/s41467-023-43580-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: 01/18/2023] [Accepted: 11/14/2023] [Indexed: 11/29/2023] Open
Abstract
Enzymatic breakdown of sphingomyelin by sphingomyelinase (SMase) is the main source of the membrane lipids, ceramides, which are involved in many cellular physiological processes. However, the full-length structure of human neutral SMase has not been resolved; therefore, its catalytic mechanism remains unknown. Here, we resolve the structure of human full-length neutral SMase, sphingomyelinase 1 (SMPD2), which reveals that C-terminal transmembrane helices contribute to dimeric architecture of hSMPD2 and that D111 - K116 loop domain is essential for substrate hydrolysis. Coupled with molecular docking, we clarify the binding pose of sphingomyelin, and site-directed mutagenesis further confirms key residues responsible for sphingomyelin binding. Hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamic (MD) simulations are utilized to elaborate the catalysis of hSMPD2 with the reported in vitro substrates, sphingomyelin and lyso-platelet activating fator (lyso-PAF). Our study provides mechanistic details that enhance our knowledge of lipid metabolism and may lead to an improved understanding of ceramide in disease and in cancer treatment.
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Affiliation(s)
- Jingbo Yi
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Boya Qi
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jian Yin
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ruochong Li
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xudong Chen
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Junhan Hu
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Guohui Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Yuebin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Cryo-EM Facility Center, Southern University of Science & Technology, Shenzhen, China.
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2
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Mühle C, Kornhuber J. Characterization of a Neutral Sphingomyelinase Activity in Human Serum and Plasma. Int J Mol Sci 2023; 24:ijms24032467. [PMID: 36768790 PMCID: PMC9916453 DOI: 10.3390/ijms24032467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Alterations of sphingolipids and their metabolizing enzymes play a role in various diseases. However, peripheral biomarkers for such changes are limited. Particularly, in the increasingly reported involvement of neutral sphingomyelinase (NSM) with four described isoforms in tissues or cells, a peripheral marker is lacking. We here describe the detection of an NSM activity in human serum and plasma samples which hydrolyses fluorescently labeled sphingomyelin to ceramide in a time- and volume-dependent manner. Reaction rates were linear up to 10 days, and serum volumes above 2 vol-% were inhibitory. Biochemical properties were different from acid sphingomyelinase (ASM) with respect to detergent specificity (sodium deoxycholate), pH profile (pH 7-9), and cation dependence: Serum NSM activity was inhibited by EDTA ≥ 1 µM and restored in EDTA-anticoagulated plasma with the addition of ≥ 100 µM Co2+. It was independent of Mg2+, the typical cofactor of cellular NSM species, and even inhibited by [Mg2+] ≥ 20 mM. Serum NSM activity was not correlated with ASM activity and was independent of sex and age in 24 healthy adults. Since human peripheral NSM activity is very low and activities in rodents are even lower or undetectable, future research should aim to increase the reaction rate and determine the source of this enzymatic activity. The established activity could serve as a future biomarker or therapeutic target in diseases affected by sphingolipid derangements.
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Affiliation(s)
- Christiane Mühle
- Correspondence: ; Tel.: +49-9131-85-44738; Fax: +49-9131-85-36381
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3
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Xing ZK, Du LS, Fang X, Liang H, Zhang SN, Shi L, Kuang CX, Han TX, Yang Q. The relationship among amyloid-β deposition, sphingomyelin level, and the expression and function of P-glycoprotein in Alzheimer's disease pathological process. Neural Regen Res 2022; 18:1300-1307. [PMID: 36453415 PMCID: PMC9838140 DOI: 10.4103/1673-5374.358607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In Alzheimer's disease, the transporter P-glycoprotein is responsible for the clearance of amyloid-β in the brain. Amyloid-β correlates with the sphingomyelin metabolism, and sphingomyelin participates in the regulation of P-glycoprotein. The amyloid cascade hypothesis describes amyloid-β as the central cause of Alzheimer's disease neuropathology. Better understanding of the change of P-glycoprotein and sphingomyelin along with amyloid-β and their potential association in the pathological process of Alzheimer's disease is critical. Herein, we found that the expression of P-glycoprotein in APP/PS1 mice tended to increase with age and was significantly higher at 9 and 12 months of age than that in wild-type mice at comparable age. The functionality of P-glycoprotein of APP/PS1 mice did not change with age but was significantly lower than that of wild-type mice at 12 months of age. Decreased sphingomyelin levels, increased ceramide levels, and the increased expression and activity of neutral sphingomyelinase 1 were observed in APP/PS1 mice at 9 and 12 months of age compared with the levels in wild-type mice. Similar results were observed in the Alzheimer's disease mouse model induced by intracerebroventricular injection of amyloid-β1-42 and human cerebral microvascular endothelial cells treated with amyloid-β1-42. In human cerebral microvascular endothelial cells, neutral sphingomyelinase 1 inhibitor interfered with the changes of sphingomyelin metabolism and P-glycoprotein expression and functionality caused by amyloid-β1-42 treatment. Neutral sphingomyelinase 1 regulated the expression and functionality of P-glycoprotein and the levels of sphingomyelin and ceramide. Together, these findings indicate that neutral sphingomyelinase 1 regulates the expression and function of P-glycoprotein via the sphingomyelin/ceramide pathway. These studies may serve as new pursuits for the development of anti-Alzheimer's disease drugs.
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Affiliation(s)
- Zi-Kang Xing
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Li-Sha Du
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Xin Fang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Heng Liang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Sheng-Nan Zhang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Lei Shi
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China
| | - Chun-Xiang Kuang
- Shanghai Key Lab of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Shanghai, China
| | - Tian-Xiong Han
- Department of Traditional Chinese Medicine, Tenth People’s Hospital of Tongji University, Shanghai, China
| | - Qing Yang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, China,Correspondence to: Qing Yang, .
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Chen X, Li J, Gao Z, Yang Y, Kuang W, Dong Y, Chua GH, Huang X, Jiang B, Tian H, Wang Y, Huang X, Li Y, Lam SM, Shui G. Endogenous ceramide phosphoethanolamine modulates circadian rhythm via neural-glial coupling in Drosophila. Natl Sci Rev 2022; 9:nwac148. [PMID: 36713590 PMCID: PMC9875363 DOI: 10.1093/nsr/nwac148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 06/08/2022] [Accepted: 07/13/2022] [Indexed: 02/01/2023] Open
Abstract
While endogenous lipids are known to exhibit rhythmic oscillations, less is known about how specific lipids modulate circadian behavior. Through a series of loss-of-function and gain-of-function experiments on ceramide phosphoethanolamine (CPE) synthase of Drosophila, we demonstrated that pan-glial-specific deficiency in membrane CPE, the structural analog of mammalian sphingomyelin (SM), leads to arrhythmic locomotor behavior and shortens lifespan, while the reverse is true for increasing CPE. Comparative proteomics uncovered dysregulated synaptic glutamate utilization and transport in CPE-deficient flies. An extensive genetic screen was conducted to verify the role of differentially expressed proteins in circadian regulation. Arrhythmic locomotion under cpes1 mutant background was rescued only by restoring endogenous CPE or SM through expressing their respective synthases. Our results underscore the essential role of CPE in maintaining synaptic glutamate homeostasis and modulating circadian behavior in Drosophila. The findings suggest that region-specific elevations of functional membrane lipids can benefit circadian regulation.
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Affiliation(s)
| | | | - Zhongbao Gao
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yang Yang
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenqing Kuang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Dong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gek Huey Chua
- LipidALL Technologies Company Limited, Changzhou213022, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China
| | - Binhua Jiang
- LipidALL Technologies Company Limited, Changzhou213022, China
| | - He Tian
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing100101, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- University of Chinese Academy of Sciences, Beijing 100049, China,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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5
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Fujita J, Taniguchi M, Hashizume C, Ueda Y, Sakai S, Kondo T, Hashimoto-Nishimura M, Hanada K, Kosaka T, Okazaki T. Nuclear Ceramide Is Associated with Ataxia Telangiectasia Mutated Activation in the Neocarzinostatin-Induced Apoptosis of Lymphoblastoid Cells. Mol Pharmacol 2022; 101:322-333. [PMID: 35273080 DOI: 10.1124/molpharm.121.000379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/22/2022] [Indexed: 01/14/2023] Open
Abstract
Ceramide is a bioactive sphingolipid that mediates ionizing radiation- and chemotherapy-induced apoptosis. Neocarzinostatin (NCS) is a genotoxic anti-cancer drug that induces apoptosis in response to DNA double-strand breaks (DSBs) through ataxia telangiectasia mutated (ATM) activation. However, the involvement of ceramide in NCS-evoked nuclear events such as DSB-activated ATM has not been clarified. Here, we found that nuclear ceramide increased by NCS-mediated apoptosis through the enhanced assembly of ATM and the meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 (MRN) complex proteins in human lymphoblastoid L-39 cells. NCS induced an increase of ceramide production through activation of neutral sphingomyelinase (nSMase) and suppression of sphingomyelin synthase (SMS) upstream of DSB-mediated ATM activation. In ATM-deficient lymphoblastoid AT-59 cells compared with L-39 cells, NCS treatment showed a decrease of apoptosis even though ceramide increase and DSBs were observed. Expression of wild-type ATM, but not the kinase-dead mutant ATM, in AT-59 cells increased NCS-induced apoptosis despite similar ceramide accumulation. Interestingly, NCS increased ceramide content in the nucleus through nSMase activation and SMS suppression and promoted colocalization of ceramide with phosphorylated ATM and foci of MRN complex. Inhibition of ceramide generation by the overexpression of SMS suppressed NCS-induced apoptosis through the inhibition of ATM activation and assembly of the MRN complex. In addition, inhibition of ceramide increased by the nSMase inhibitor GW4869 prevented NCS-mediated activation of the ATM. Therefore, our findings suggest the involvement of the nuclear ceramide with ATM activation in NCS-mediated apoptosis. SIGNIFICANCE STATEMENT: This study demonstrates that regulation of ceramide with neutral sphingomyelinase and sphingomyelin synthase in the nucleus in double-strand break-mimetic agent neocarzinostatin (NCS)-induced apoptosis. This study also showed that ceramide increase in the nucleus plays a role in NCS-induced apoptosis through activation of the ataxia telangiectasia mutated/meiotic recombination 11/double-strand break repair/Nijmengen breakage syndrome 1 complex in human lymphoblastoid cells.
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Affiliation(s)
- Jun Fujita
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Makoto Taniguchi
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Chieko Hashizume
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Yoshibumi Ueda
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Shota Sakai
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Tadakazu Kondo
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Mayumi Hashimoto-Nishimura
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Kentaro Hanada
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Takeo Kosaka
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
| | - Toshiro Okazaki
- Division of General and Digestive Surgery, Department of Medicine (J.F., C.H., T.K.) and Medical Research Institute (M.T.), Kanazawa Medical University, Ishikawa, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Ishikawa, Japan (C.H., T.O.); Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (Y.U.); Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan. (S.S., K.H.); Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan (T.K.); and Department of Hematology/Oncology, Faculty of Medicine, Tottori University, Yonago, Japan (M.H.-N.)
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Silvera S, Wilkinson JA, LeBlanc PJ. Characterization of neutral sphingomyelinase activity and isoform expression in rodent skeletal muscle mitochondria. Mitochondrion 2021; 59:184-189. [PMID: 34089907 DOI: 10.1016/j.mito.2021.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/04/2021] [Accepted: 06/01/2021] [Indexed: 12/01/2022]
Abstract
Skeletal muscle is composed of fiber types that differ in mitochondrial content, antioxidant capacity, and susceptibility to apoptosis. Ceramides have been linked to oxidative stress-mediated apoptotic intracellular signalling and the enzyme neutral sphingomyelinase (nSMase) is, in part, responsible for generating these ceramides through the hydrolysis of sphingomyelin. Despite the role of ceramides in mediating apoptosis, there is a gap in the literature regarding nSMase in skeletal muscle mitochondria. This study aimed to characterize total nSMase activity and individual isoform expression in isolated subsarcolemmal (SS) mitochondria from soleus, diaphragm, plantaris, and extensor digitorum longus (EDL). Total nSMase activity did not differ between muscle types. nSMase2 content was detectable in all muscles and higher in EDL, soleus, and plantaris compared to diaphragm whereas nSMase3 was undetectable in all muscles. Finally, total nSMase activity positively correlated to nSMase2 protein content in soleus but not the other muscles. These findings suggest that nSMase associated with SS mitochondria may play a role in intracellular signalling processes involving ceramides in skeletal muscle and nSMase2 may be the key isoform, specifically in slow twitch muscle like soleus. Further studies are needed to fully elucidate the specific contribution of nSMase, along with the role of the various isoforms and mitochondrial subpopulation in generating mitochondrial ceramides in skeletal muscle, and its potential effects on mediating apoptosis.
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Affiliation(s)
- Sebastian Silvera
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada
| | - Jennifer A Wilkinson
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada
| | - Paul J LeBlanc
- Center for Bone and Muscle Health, Faculty of Applied Health Science, Brock University, Canada.
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7
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Stoffel W, Hammels I, Jenke B, Schmidt-Soltau I, Niehoff A. Neutral Sphingomyelinase 2 (SMPD3) Deficiency in Mice Causes Chondrodysplasia with Unimpaired Skeletal Mineralization. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:1831-1845. [PMID: 31199918 DOI: 10.1016/j.ajpath.2019.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 05/10/2019] [Accepted: 05/14/2019] [Indexed: 10/26/2022]
Abstract
SMPD3 deficiency in the neutral sphingomyelinase (Smpd3-/-) mouse results in a novel form of juvenile dwarfism, suggesting smpd3 is a polygenetic determinant of body height. SMPD3 controls homeostasis of the sphingomyelin cycle in the Golgi compartment, essential for membrane remodeling, initiating multiform vesicle formation and transport in the Golgi secretory pathway. Using the unbiased Smpd3-/- genetic model, this study shows that the perturbed Golgi secretory pathway of chondrocytes of the epiphyseal growth zone leads to dysproteostasis, skeletal growth inhibition, malformation, and chondrodysplasia, but showed unimpaired mineralization in primary and secondary enchondral ossification centers. This has been elaborated by biochemical analyses and immunohistochemistry of long bones of Smpd3-/- mice. A more precise definition of the microarchitecture and three-dimensional structure of the bone was shown by peripheral quantitative computed tomography, high-resolution microcomputed tomography, and less precisely by dual-energy X-ray absorptiometry for osteodensitometry. Ablation of the Smpd3 locus as part of a 980-kb deletion on chromosome 8 in the fro/fro mutant, generated by chemical mutagenesis, is held responsible for skeletal hypomineralization, osteoporosis, and multiple fractures of long bones, which are hallmarks of human osteogenesis imperfecta. The phenotype of the genetically unbiased Smpd3-/- mouse, described here, precludes the proposed role of Smpd3 as a candidate gene of human osteogenesis imperfecta, but suggests SMPD3 deficiency as the pathogenetic basis of a novel form of chondrodysplasia.
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Affiliation(s)
- Wilhelm Stoffel
- Laboratory of Molecular Neurosciences, Center of Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany; Center of Molecular Medicine, University of Cologne, Cologne, Germany; Cluster of Excellence, Cellular Stress Responses in Age Associated Diseases, University of Cologne, Cologne, Germany.
| | - Ina Hammels
- Laboratory of Molecular Neurosciences, Center of Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany; Center of Molecular Medicine, University of Cologne, Cologne, Germany
| | - Britta Jenke
- Laboratory of Molecular Neurosciences, Center of Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany; Center of Molecular Medicine, University of Cologne, Cologne, Germany
| | - Inga Schmidt-Soltau
- Laboratory of Molecular Neurosciences, Center of Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany; Center of Molecular Medicine, University of Cologne, Cologne, Germany
| | - Anja Niehoff
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne Center for Musculoskeletal Biomechanics, Faculty of Medicine, University of Cologne, Cologne, Germany
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8
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Stoffel W, Jenke B, Schmidt-Soltau I, Binczek E, Brodesser S, Hammels I. SMPD3 deficiency perturbs neuronal proteostasis and causes progressive cognitive impairment. Cell Death Dis 2018; 9:507. [PMID: 29725009 PMCID: PMC5938706 DOI: 10.1038/s41419-018-0560-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/05/2018] [Indexed: 11/15/2022]
Abstract
Neutral sphingomyelinase smpd3 is most abundantly expressed in neurons of brain. The function of SMPD3 has remained elusive. Here, we report a pathogenetic nexus between absence of SMPD3 in the Golgi compartment (GC) of neurons of the smpd3-/- mouse brain, inhibition of Golgi vesicular protein transport and progressive cognitive impairment. Absence of SMPD3 activity in the Golgi sphingomyelin cycle impedes remodeling of the lipid bilayer, essential for budding and multivesicular body formation. Importantly, we show that inhibition of the Golgi vesicular protein transport causes accumulation of neurotoxic proteins APP, Aβ and phosphorylated Tau, dysproteostasis, unfolded protein response, and apoptosis, which ultimately manifests in progressive cognitive decline, similar to the pathognomonic signatures of familial and sporadic forms of Alzheimer´s disease. This discovery might contribute to the search for other primary pathogenic mechanisms, which link perturbed lipid bilayer structures and protein processing and transport in the neuronal Golgi compartment and neurodegeneration and cognitive deficits.
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Affiliation(s)
- Wilhelm Stoffel
- Laboratory of Molecular Neuroscience, Institute of Biochemistry, University of Cologne, 50931, Cologne, Germany. .,CMMC (Centre for Molecular Medicine), University of Cologne, 50931, Cologne, Germany. .,CECAD (Cluster of Excellence: Cellular Stress Responses in Aging-Associated Diseases), University of Cologne, 50931, Cologne, Germany.
| | - Britta Jenke
- CMMC (Centre for Molecular Medicine), University of Cologne, 50931, Cologne, Germany
| | - Inga Schmidt-Soltau
- CMMC (Centre for Molecular Medicine), University of Cologne, 50931, Cologne, Germany
| | - Erika Binczek
- Laboratory of Molecular Neuroscience, Institute of Biochemistry, University of Cologne, 50931, Cologne, Germany
| | - Susanne Brodesser
- CECAD (Cluster of Excellence: Cellular Stress Responses in Aging-Associated Diseases), University of Cologne, 50931, Cologne, Germany
| | - Ina Hammels
- Laboratory of Molecular Neuroscience, Institute of Biochemistry, University of Cologne, 50931, Cologne, Germany
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Zhou Y, Lin XW, Begum MA, Zhang CH, Shi XX, Jiao WJ, Zhang YR, Yuan JQ, Li HY, Yang Q, Mao C, Zhu ZR. Identification and characterization of Laodelphax striatellus (Insecta: Hemiptera: Delphacidae) neutral sphingomyelinase. INSECT MOLECULAR BIOLOGY 2017; 26:392-402. [PMID: 28374513 DOI: 10.1111/imb.12302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The neutral sphingomyelinase (nSMase) 1 homologue gene LsSMase was cloned from Laodelphax striatellus, a direct sap-sucker and virus vector of gramineous plants, and expressed via a Bac to Bac baculovirus expression system. The LsSMase-enhanced green fluorescent protein fusion protein was located in the endoplasmic reticulum in a similar manner to mammalian nSMase 1. The biochemical properties of LsSMase were determined in detail. The optimal pH and temperature for recombinant LsSMase were 8 and 37 °C, respectively. LsSMase was an Mg2+ or Mn2+ dependent enzyme, but different concentration of each were needed. The activity of LsSMase was significantly stimulated by Ethylene glycol bis(2-aminoethyl ether)tetraacetic acid (EGTA), whereas it was inhibited by ethylenediaminetetraacetic acid. Millimolar concentrations of Zn2+ completely inhibited LsSMase. The reducing agents dithiothreitol and β-mercaptoethanol varied in their effects on activity. Phospholipids were not found to stimulate LsSMase.
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Affiliation(s)
- Y Zhou
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - X-W Lin
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - M-A Begum
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - C-H Zhang
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - X-X Shi
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - W-J Jiao
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Y-R Zhang
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - J-Q Yuan
- Center for Chemical Analysis and Detection, Zhejiang University, Hangzhou, Zhejiang, China
| | - H-Y Li
- Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Q Yang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - C Mao
- Department of Medicine, State University of New York at Stony Brook. Stony Brook, NY, USA
| | - Z-R Zhu
- State Key Laboratory of Rice Biology; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects; and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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10
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Neutral sphingomyelinase (SMPD3) deficiency disrupts the Golgi secretory pathway and causes growth inhibition. Cell Death Dis 2016; 7:e2488. [PMID: 27882938 PMCID: PMC5260872 DOI: 10.1038/cddis.2016.385] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 01/27/2023]
Abstract
Systemic loss of neutral sphingomyelinase (SMPD3) in mice leads to a novel form of systemic, juvenile hypoplasia (dwarfism). SMPD3 deficiency in mainly two growth regulating cell types contributes to the phenotype, in chondrocytes of skeletal growth zones to skeletal malformation and chondrodysplasia, and in hypothalamic neurosecretory neurons to systemic hypothalamus–pituitary–somatotropic hypoplasia. The unbiased smpd3−/− mouse mutant and derived smpd3−/− primary chondrocytes were instrumental in defining the enigmatic role underlying the systemic and cell autonomous role of SMPD3 in the Golgi compartment. Here we describe the unprecedented role of SMPD3. SMPD3 deficiency disrupts homeostasis of sphingomyelin (SM), ceramide (Cer) and diacylglycerol (DAG) in the Golgi SMPD3-SMS1 (SM-synthase1) cycle. Cer and DAG, two fusogenic intermediates, modify the membrane lipid bilayer for the initiation of vesicle formation and transport. Dysproteostasis, unfolded protein response, endoplasmic reticulum stress and apoptosis perturb the Golgi secretory pathway in the smpd3−/− mouse. Secretion of extracellular matrix proteins is arrested in chondrocytes and causes skeletal malformation and chondrodysplasia. Similarly, retarded secretion of proteo-hormones in hypothalamic neurosecretory neurons leads to hypothalamus induced combined pituitary hormone deficiency. SMPD3 in the regulation of the protein vesicular secretory pathway may become a diagnostic target in the etiology of unknown forms of juvenile growth and developmental inhibition.
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11
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Bienias K, Fiedorowicz A, Sadowska A, Prokopiuk S, Car H. Regulation of sphingomyelin metabolism. Pharmacol Rep 2016; 68:570-81. [PMID: 26940196 DOI: 10.1016/j.pharep.2015.12.008] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 11/24/2015] [Accepted: 12/28/2015] [Indexed: 12/17/2022]
Abstract
Sphingolipids (SFs) represent a large class of lipids playing diverse functions in a vast number of physiological and pathological processes. Sphingomyelin (SM) is the most abundant SF in the cell, with ubiquitous distribution within mammalian tissues, and particularly high levels in the Central Nervous System (CNS). SM is an essential element of plasma membrane (PM) and its levels are crucial for the cell function. SM content in a cell is strictly regulated by the enzymes of SM metabolic pathways, which activities create a balance between SM synthesis and degradation. The de novo synthesis via SM synthases (SMSs) in the last step of the multi-stage process is the most important pathway of SM formation in a cell. The SM hydrolysis by sphingomyelinases (SMases) increases the concentration of ceramide (Cer), a bioactive molecule, which is involved in cellular proliferation, growth and apoptosis. By controlling the levels of SM and Cer, SMSs and SMases maintain cellular homeostasis. Enzymes of SM cycle exhibit unique properties and diverse tissue distribution. Disturbances in their activities were observed in many CNS pathologies. This review characterizes the physiological roles of SM and enzymes controlling SM levels as well as their involvement in selected pathologies of the Central Nervous System, such as ischemia/hypoxia, Alzheimer disease (AD), Parkinson disease (PD), depression, schizophrenia and Niemann Pick disease (NPD).
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Affiliation(s)
- Kamil Bienias
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Anna Fiedorowicz
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland; Laboratory of Tumor Molecular Immunobiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Anna Sadowska
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Sławomir Prokopiuk
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Halina Car
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland.
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12
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Kitatani K, Taniguchi M, Okazaki T. Role of Sphingolipids and Metabolizing Enzymes in Hematological Malignancies. Mol Cells 2015; 38:482-95. [PMID: 25997737 PMCID: PMC4469906 DOI: 10.14348/molcells.2015.0118] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 05/07/2015] [Indexed: 12/16/2022] Open
Abstract
Sphingolipids such as ceramide, sphingosine-1-phosphate and sphingomyelin have been emerging as bioactive lipids since ceramide was reported to play a role in human leukemia HL-60 cell differentiation and death. Recently, it is well-known that ceramide acts as an inducer of cell death, that sphingomyelin works as a regulator for microdomain function of the cell membrane, and that sphingosine-1-phosphate plays a role in cell survival/proliferation. The lipids are metabolized by the specific enzymes, and each metabolite could be again returned to the original form by the reverse action of the different enzyme or after a long journey of many metabolizing/synthesizing pathways. In addition, the metabolites may serve as reciprocal bio-modulators like the rheostat between ceramide and sphingosine-1-phosphate. Therefore, the change of lipid amount in the cells, the subcellular localization and the downstream signal in a specific subcellular organelle should be clarified to understand the pathobiological significance of sphingolipids when extracellular stimulation induces a diverse of cell functions such as cell death, proliferation and migration. In this review, we focus on how sphingolipids and their metabolizing enzymes cooperatively exert their function in proliferation, migration, autophagy and death of hematopoetic cells, and discuss the way developing a novel therapeutic device through the regulation of sphingolipids for effectively inhibiting cell proliferation and inducing cell death in hematological malignancies such as leukemia, malignant lymphoma and multiple myeloma.
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Affiliation(s)
- Kazuyuki Kitatani
- Tohoku Medical Megabank Organization, Sendai,
Japan
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai,
Japan
| | - Makoto Taniguchi
- Medical Research Institute, Kanazawa Medical University, Uchinada, Ishikawa 920-0293,
Japan
| | - Toshiro Okazaki
- Medical Research Institute, Kanazawa Medical University, Uchinada, Ishikawa 920-0293,
Japan
- Department of Medicine, Division of Hematology/Immunology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293,
Japan
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Yabu T, Shiba H, Shibasaki Y, Nakanishi T, Imamura S, Touhata K, Yamashita M. Stress-induced ceramide generation and apoptosis via the phosphorylation and activation of nSMase1 by JNK signaling. Cell Death Differ 2014; 22:258-73. [PMID: 25168245 PMCID: PMC4291487 DOI: 10.1038/cdd.2014.128] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 12/20/2022] Open
Abstract
Neutral sphingomyelinase (nSMase) activation in response to environmental stress or inflammatory cytokine stimuli generates the second messenger ceramide, which mediates the stress-induced apoptosis. However, the signaling pathways and activation mechanism underlying this process have yet to be elucidated. Here we show that the phosphorylation of nSMase1 (sphingomyelin phosphodiesterase 2, SMPD2) by c-Jun N-terminal kinase (JNK) signaling stimulates ceramide generation and apoptosis and provide evidence for a signaling mechanism that integrates stress- and cytokine-activated apoptosis in vertebrate cells. An nSMase1 was identified as a JNK substrate, and the phosphorylation site responsible for its effects on stress and cytokine induction was Ser-270. In zebrafish cells, the substitution of Ser-270 for alanine blocked the phosphorylation and activation of nSMase1, whereas the substitution of Ser-270 for negatively charged glutamic acid mimicked the effect of phosphorylation. The JNK inhibitor SP600125 blocked the phosphorylation and activation of nSMase1, which in turn blocked ceramide signaling and apoptosis. A variety of stress conditions, including heat shock, UV exposure, hydrogen peroxide treatment, and anti-Fas antibody stimulation, led to the phosphorylation of nSMase1, activated nSMase1, and induced ceramide generation and apoptosis in zebrafish embryonic ZE and human Jurkat T cells. In addition, the depletion of MAPK8/9 or SMPD2 by RNAi knockdown decreased ceramide generation and stress- and cytokine-induced apoptosis in Jurkat cells. Therefore the phosphorylation of nSMase1 is a pivotal step in JNK signaling, which leads to ceramide generation and apoptosis under stress conditions and in response to cytokine stimulation. nSMase1 has a common central role in ceramide signaling during the stress and cytokine responses and apoptosis.
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Affiliation(s)
- T Yabu
- Nihon University, College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - H Shiba
- Nihon University, College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Y Shibasaki
- Nihon University, College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - T Nakanishi
- Nihon University, College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - S Imamura
- Food Safety Assessment Research Group, National Research Institute of Fisheries Science, 12-4 Fukuura 2, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - K Touhata
- Food Safety Assessment Research Group, National Research Institute of Fisheries Science, 12-4 Fukuura 2, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
| | - M Yamashita
- Food Safety Assessment Research Group, National Research Institute of Fisheries Science, 12-4 Fukuura 2, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
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14
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Juric V, Chen CC, Lau LF. TNFα-induced apoptosis enabled by CCN1/CYR61: pathways of reactive oxygen species generation and cytochrome c release. PLoS One 2012; 7:e31303. [PMID: 22363611 PMCID: PMC3281933 DOI: 10.1371/journal.pone.0031303] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 01/06/2012] [Indexed: 12/20/2022] Open
Abstract
Although TNFα is a strong inducer of apoptosis, its cytotoxicity in most normal cells in vitro requires blockade of NFκB signaling or inhibition of de novo protein synthesis, typically by the addition of cycloheximide. However, several members of CCN (CYR61/CTGF/NOV) family of extracellular matrix proteins enable TNFα-dependent apoptosis in vitro without inhibiting NFκB or de novo protein synthesis, and CCN1 (CYR61) is essential for optimal TNFα cytotoxicity in vivo. Previous studies showed that CCN1 unmasks the cytotoxicity of TNFα by binding integrins α(v)β(5), α(6)β(1), and the cell surface heparan sulfate proteoglycan syndecan 4 to induce the accumulation of a high level of reactive oxygen species (ROS), leading to a biphasic activation of JNK necessary for apoptosis. Here we show for the first time that CCN1 interacts with the low density lipoprotein receptor-related protein 1 (LRP1) in a protein complex, and that binding to LRP1 is critical for CCN1-induced ROS generation and apoptotic synergism with TNFα. We also found that neutral sphingomyelinase 1 (nSMase1), which contributes to CCN1-induced ROS generation, is required for CCN1/TNFα-induced apoptosis. Furthermore, CCN1 promotes the activation of p53 and p38 MAPK, which mediate enhanced cytochrome c release to amplify the cytotoxicity of TNFα. By contrast, LRP1, nSMase1, p53, and p38 MAPK are not required when TNFα-dependent apoptosis is facilitated by the presence of cycloheximide, indicating that they function in the CCN1 signaling pathway that converges with TNFα-induced signaling events. Since CCN1/CYR61 is a physiological regulator of TNFα cytotoxicity at least in some contexts, these findings may reveal important mediators of TNFα-induced apoptosis in vivo and identify potential therapeutic targets for thwarting TNFα-dependent tissue damage.
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Affiliation(s)
- Vladislava Juric
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Chih-Chiun Chen
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Lester F. Lau
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- * E-mail:
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15
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The Roles of Neutral Sphingomyelinases in Neurological Pathologies. Neurochem Res 2012; 37:1137-49. [DOI: 10.1007/s11064-011-0692-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 11/25/2011] [Accepted: 12/29/2011] [Indexed: 12/14/2022]
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16
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Truman JP, Al Gadban MM, Smith KJ, Hammad SM. Acid sphingomyelinase in macrophage biology. Cell Mol Life Sci 2011; 68:3293-305. [PMID: 21533981 DOI: 10.1007/s00018-011-0686-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 03/28/2011] [Accepted: 04/05/2011] [Indexed: 12/21/2022]
Abstract
Macrophages play a central role in innate immune responses, in disposal of cholesterol, and in tissue homeostasis and remodeling. To perform these vital functions macrophages display high endosomal/lysosomal activities. Recent studies have highlighted that acid sphingomyelinase (ASMase), which generates ceramide from sphingomyelin, is involved in modulation of membrane structures and signal transduction in addition to its metabolic role in the lysosome. In this review, we bring together studies on ASMase, its different forms and locations that are necessary for the macrophage to accomplish its diverse functions. We also address the importance of ASMase to several disease processes that are mediated by activated macrophages.
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Affiliation(s)
- Jean-Philip Truman
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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17
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Nagai KI, Takahashi N, Moue T, Niimura Y. Alteration of fatty acid molecular species in ceramide and glucosylceramide under heat stress and expression of sphingolipid-related genes. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/abc.2011.13006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Kawamori T. Animal models for studying the pathophysiology of ceramide. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:109-17. [PMID: 20919649 DOI: 10.1007/978-1-4419-6741-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Bioactive sphingolipids play key roles in the regulation of several fundamental biological processes such as proliferation, apoptosis and transformation. The recent development of genetically engineered mouse (GEM) models has enabled the study of functional roles of sphingolipids in normal development and disease. In this chapter, we review the phenotypes of GEM models (knockout mice) that lack sphingolipid metabolism-related enzymes, discuss what we have learned from animal models and describe future directions of animal models in sphingolipid research.
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Affiliation(s)
- Toshihiko Kawamori
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina, 165 Ashley Avenue, Suite 309, MSC 908, Charleston, South Carolina 29425, USA.
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19
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Zanetti SR, de Los Ángeles Monclus M, Rensetti DE, Fornés MW, Aveldaño MI. Ceramides with 2-hydroxylated, very long-chain polyenoic fatty acids in rodents: From testis to fertilization-competent spermatozoa. Biochimie 2010; 92:1778-86. [PMID: 20831891 DOI: 10.1016/j.biochi.2010.08.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 08/13/2010] [Indexed: 10/19/2022]
Abstract
Sphingolipids from rodent testis and spermatozoa are known to contain non-hydroxylated (N-) and 2-hydroxylated (2-OH) very-long-chain polyunsaturated fatty acids (VLCPUFA). In this study, the contribution of species with each type of fatty acids to the total ceramides (Cer) and sphingomyelins (SM) was investigated in rat and mouse testis and in rat spermatozoa. The major VLCPUFA in both lipids of testis were N- and 2-OH versions of 28:4n-6, 30:5n-6 and 32:5n-6 in the rat, and predominantly of 30:5n-6 in the mouse. Absent altogether from rat pre-puberal testes, SM and Cer with N-VLCPUFA appeared 10 days earlier than those with 2-OH VLCPUFA in postnatal development, in association with germ cell differentiation. Conversely, in adult fertile rats that were gradually deprived of germ cells in vivo after treatment with doxorubicin, SM and Cer with N-VLCPUFA decreased earlier than their 2-OH counterparts, and neither was present in aspermatogenic testes. In rat epididymal spermatozoa, the content of Cer prevailed over that of SM and 2-OH VLCPUFA prevailed over N-VLCPUFA in both lipids. In mature gametes, the acrosomal reaction resulted in an almost complete hydrolysis of the species of SM that contain both types of VLCPUFA to produce the corresponding Cer. Ceramides are biosynthetic precursors of SM in the testis, but themselves final products in spermatozoa. VLCPUFA-rich SM and Cer are thus produced in germ cells with the teleological objective of fulfilling their ultimate physiological role in spermatozoa that are apt and ready to fertilize an oocyte.
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Affiliation(s)
- Samanta R Zanetti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
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20
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Wu BX, Clarke CJ, Hannun YA. Mammalian neutral sphingomyelinases: regulation and roles in cell signaling responses. Neuromolecular Med 2010; 12:320-30. [PMID: 20552297 DOI: 10.1007/s12017-010-8120-z] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 06/02/2010] [Indexed: 12/22/2022]
Abstract
Ceramide, a bioactive lipid, has been extensively studied and identified as an essential bioactive molecule in mediating cellular signaling pathways. Sphingomyelinase (SMase), (EC 3.1.4.12) catalyzes the cleavage of the phosphodiester bond in sphingomyelin (SM) to form ceramide and phosphocholine. In mammals, three Mg(2+)-dependent neutral SMases termed nSMase1, nSMase2 and nSMase3 have been identified. Among the three enzymes, nSMase2 is the most studied and has been implicated in multiple physiological responses including cell growth arrest, apoptosis, development and inflammation. In this review, we summarize recent findings for the cloned nSMases and discuss the insights for their roles in regulation ceramide metabolism and cellular signaling pathway.
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Affiliation(s)
- Bill X Wu
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425, USA
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21
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Stress-induced sphingolipid signaling: role of type-2 neutral sphingomyelinase in murine cell apoptosis and proliferation. PLoS One 2010; 5:e9826. [PMID: 20352118 PMCID: PMC2843740 DOI: 10.1371/journal.pone.0009826] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/01/2010] [Indexed: 01/18/2023] Open
Abstract
Background Sphingomyelin hydrolysis in response to stress-inducing agents, and subsequent ceramide generation, are implicated in various cellular responses, including apoptosis, inflammation and proliferation, depending on the nature of the different acidic or neutral sphingomyelinases. This study was carried out to investigate whether the neutral Mg2+-dependent neutral sphingomyelinase-2 (nSMase2) plays a role in the cellular signaling evoked by TNFalpha and oxidized LDLs, two stress-inducing agents, which are mitogenic at low concentrations and proapoptotic at higher concentrations. Methodology and Principal Findings For this purpose, we used nSMase2-deficient cells from homozygous fro/fro (fragilitas ossium) mice and nSMase2-deficient cells reconstituted with a V5-tagged nSMase2. We report that the genetic defect of nSMase2 (in fibroblasts from fro/fro mice) does not alter the TNFalpha and oxidized LDLs-mediated apoptotic response. Likewise, the hepatic toxicity of TNFalpha is similar in wild type and fro mice, thus is independent of nSMase2 activation. In contrast, the mitogenic response elicited by low concentrations of TNFalpha and oxidized LDLs (but not fetal calf serum) requires nSMase2 activation. Conclusion and Significance nSMase2 activation is not involved in apoptosis mediated by TNFalpha and oxidized LDLs in murine fibroblasts, and in the hepatotoxicity of TNFalpha in mice, but is required for the mitogenic response to stress-inducing agents.
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22
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Gault CR, Obeid LM, Hannun YA. An overview of sphingolipid metabolism: from synthesis to breakdown. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:1-23. [PMID: 20919643 DOI: 10.1007/978-1-4419-6741-1_1] [Citation(s) in RCA: 727] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sphingolipids constitute a class of lipids defined by their eighteen carbon amino-alcohol backbones which are synthesized in the ER from nonsphingolipid precursors. Modification of this basic structure is what gives rise to the vast family of sphingolipids that play significant roles in membrane biology and provide many bioactive metabolites that regulate cell function. Despite the diversity of structure and function of sphingolipids, their creation and destruction are governed by common synthetic and catabolic pathways. In this regard, sphingolipid metabolism can be imagined as an array of interconnected networks that diverge from a single common entry point and converge into a single common breakdown pathway. In their simplest forms, sphingosine, phytosphingosine and dihydrosphingosine serve as the backbones upon which further complexity is achieved. For example, phosphorylation of the C1 hydroxyl group yields the final breakdown products and/or the important signaling molecules sphingosine-1-phosphate, phytosphingosine-1-phosphate and dihydrosphingosine-1-phosphate, respectively. On the other hand, acylation of sphingosine, phytosphingosine, or dihydrosphingosine with one of several possible acyl CoA molecules through the action of distinct ceramide synthases produces the molecules defined as ceramide, phytoceramide, or dihydroceramide. Ceramide, due to the differing acyl CoAs that can be used to produce it, is technically a class of molecules rather than a single molecule and therefore may have different biological functions depending on the acyl chain it is composed of. At the apex of complexity is the group of lipids known as glycosphingolipids (GSL) which contain dozens of different sphingolipid species differing by both the order and type of sugar residues attached to their headgroups. Since these molecules are produced from ceramide precursors, they too may have differences in their acyl chain composition, revealing an additional layer of variation. The glycosphingolipids are divided broadly into two categories: glucosphingolipids and galactosphingolipids. The glucosphingolipids depend initially on the enzyme glucosylceramide synthase (GCS) which attaches glucose as the first residue to the C1 hydroxyl position. Galactosphingolipids, on the other hand, are generated from galactosylceramide synthase (GalCerS), an evolutionarily dissimilar enzyme from GCS. Glycosphingolipids are further divided based upon further modification by various glycosyltransferases which increases the potential variation in lipid species by several fold. Far more abundant are the sphingomyelin species which are produced in parallel with glycosphingolipids, however they are defined by a phosphocholine headgroup rather than the addition of sugar residues. Although sphingomyelin species all share a common headgroup, they too are produced from a variety of ceramide species and therefore can have differing acyl chains attached to their C-2 amino groups. Whether or not the differing acyl chain lengths in SMs dictate unique functions or important biophysical distinctions has not yet been established. Understanding the function of all the existing glycosphingolipids and sphingomyelin species will be a major undertaking in the future since the tools to study and measure these species are only beginning to be developed (see Fig 1 for an illustrated depiction of the various sphingolipid structures). The simple sphingolipids serve both as the precursors and the breakdown products of the more complex ones. Importantly, in recent decades, these simple sphingolipids have gained attention for having significant signaling and regulatory roles within cells. In addition, many tools have emerged to measure the levels of simple sphingolipids and therefore have become the focus of even more intense study in recent years. With this thought in mind, this chapter will pay tribute to the complex sphingolipids, but focus on the regulation of simple sphingolipid metabolism.
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Affiliation(s)
- Christopher R Gault
- Department of Biochemistry, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Ceramide and cholesterol: possible connections between normal aging of the brain and Alzheimer's disease. Just hypotheses or molecular pathways to be identified? Alzheimers Dement 2009; 1:43-50. [PMID: 19595816 DOI: 10.1016/j.jalz.2005.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Even though it is known that aging is the single most important risk factor for Alzheimer's disease (AD), there is a lack of information on the molecular pathway(s) that connect normal aging of the brain to this form of neuropathology. Because of the rise in average lifespan, the number of individuals that reach the seventh or eighth decade of life and become at high risk for AD is rapidly increasing. Current estimations predict that by 2050 about 45 to 50 million individuals will be affected by AD worldwide. Here, we discuss the need for more age-directed research to understand AD neuropathology. We also elaborate on the possible role of cholesterol and ceramide as molecular connections between aging and AD, and as novel therapeutic targets for the prevention of late-onset AD.
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Camino-López S, Badimon L, González A, Canals D, Peña E, Llorente-Cortés V. Aggregated low density lipoprotein induces tissue factor by inhibiting sphingomyelinase activity in human vascular smooth muscle cells. J Thromb Haemost 2009; 7:2137-46. [PMID: 19817993 DOI: 10.1111/j.1538-7836.2009.03638.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Our previous results demonstrated that aggregated low density lipoprotein (agLDL) induces tissue factor (TF) expression and activation through Rho A translocation in human vascular smooth muscle cells (VSMC). We also previously demonstrated that membrane sphingomyelin (SM) content is higher in agLDL-exposed VSMC than in control cells. The main enzymes regulating cellular SM content are the family of sphingomyelinases (Smases) that hydrolize SM to phosphorylcholine and ceramide (CER). OBJECTIVES We wished to investigate whether agLDL has the ability to modulate acidic- (A-) and neutral (N-) Smase activity and whether or not this effect is related to the upregulatory effect of agLDL on Rho A translocation and TF activation in human VSMC. METHODS AND RESULTS By measuring generated [(14)C]-phosphorylcholine, we found that agLDL significantly decreased A-Smase and specially N-Smase activity. Pharmacological Smase inhibitors increased Rho A and TF. Specific loss-of-function of A-Smase or N-Smase 1 (N1-Smase) by siRNA treatment (500 nmol L(-1), 12 hours) dramatically increased membrane Rho A protein levels (5- and 3-fold, respectively). Concomitantly, TF protein expression and TF procoagulant activity were also increased. Inhibition of A-Smase or N-Smase activity by agLDL, siRNA-anti A- or N1-Smase or pharmacological treatment significantly increased the SM content of vascular cells. The inhibition of SM synthesis by fumonisin B(1) (FB(1)) prevented the upregulatory effect of agLDL on TF. CONCLUSIONS These results demonstrate that inhibition of both A- and N1-Smase might explain the upregulatory effect of agLDL on TF activation, and suggest that this effect is related, at least in part, to membrane SM enrichment.
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Affiliation(s)
- S Camino-López
- Cardiovascular Research Center of Barcelona, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, Barcelona
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Zhu D, Sreekumar PG, Hinton DR, Kannan R. Expression and regulation of enzymes in the ceramide metabolic pathway in human retinal pigment epithelial cells and their relevance to retinal degeneration. Vision Res 2009; 50:643-51. [PMID: 19765607 DOI: 10.1016/j.visres.2009.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 09/06/2009] [Accepted: 09/09/2009] [Indexed: 02/07/2023]
Abstract
Ceramide and its metabolic derivatives are important modulators of cellular apoptosis and proliferation. Dysregulation or imbalance of their metabolic pathways may promote the development of retinal degeneration. The aim of this study was to identify the expression and regulation of key enzymes of the ceramide pathway in retinal pigment epithelial (RPE) cells. RT-PCR was used to screen the enzymes involved in ceramide metabolism that are expressed in RPE. Over-expression of neutral sphingomyelinase-2 (SMPD3) or sphingosine kinase 1 (Sphk1) in ARPE-19 cells was achieved by transient transfection of SMPD3 or Sphk1 cDNA subcloned into an expression vector. The number of apoptotic or proliferating cells was determined using TUNEL and BrdU assays, respectively. Neutral sphingomyelinase-1, neutral sphingomyelinase-2, acidic ceramidase, ceramide kinase, SphK1 and Sphk2 were expressed in both ARPE-19 and early passage human fetal RPE (fRPE) cells, while alkaline ceramidase 2 was only expressed in fRPE cells. Over-expression of SMPD3 decreased RPE cell proliferation and increased cell apoptosis. The percentage of apoptotic cells increased proportionally with the amount of transfected SMPD3 DNA. Over-expression of SphK1 promoted cell proliferation and protected ARPE-19 cells from ceramide-induced apoptosis. The effect of C(2) ceramide on induction of apoptosis was evaluated in polarized vs. non-polarized RPE cultures; polarization of RPE was associated with much reduced apoptosis in response to ceramide. In conclusion, RPE cells possess the synthetic machinery for the production of ceramide, sphingosine, ceramide-1-phosphate (C1P), and sphingosine-1-phosphate (S1P). Over-expression of SMPD3 may increase cellular ceramide levels, leading to enhanced cell death and arrested cell proliferation. The selective induction of apoptosis in non-polarized RPE cultures by C(2) ceramide suggests that increased ceramide levels will preferentially affect non-polarized RPE, as are found in late age-related macular degeneration lesions, and may spare the normal RPE monolayer. SphK1 over-expression increased cellular S1P, which promoted cell proliferation and protected RPE from ceramide-induced apoptosis. Understanding the relationship between the metabolism of sphingolipids and their effects in RPE cell survival/death may help us to develop effective and efficient therapies for retinal degeneration.
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Affiliation(s)
- DanHong Zhu
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, USA
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Yabu T, Shimuzu A, Yamashita M. A novel mitochondrial sphingomyelinase in zebrafish cells. J Biol Chem 2009; 284:20349-63. [PMID: 19429680 DOI: 10.1074/jbc.m109.004580] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sphingolipids are important signaling molecules in many biological processes, but little is known regarding their physiological roles in the mitochondrion. We focused on the biochemical characters of a novel sphingomyelinase (SMase) and its function in mitochondrial ceramide generation in zebrafish embryonic cells. The cloned SMase cDNA encoded a polypeptide of 545 amino acid residues (putative molecular weight, 61,300) containing a mitochondrial localization signal (MLS) and a predicted transmembrane domain. The mature endogenous enzyme was predicted to have a molecular weight of 57,000, and matrix-assisted laser de sorption ionization time-of-flight mass spectrometry analysis indicated that the N-terminal amino acid residue of the mature enzyme was Ala-36. The purified enzyme optimally hydrolyzed [(14)C]sphingomyelin in the presence of 10 mm Mg(2+) at pH 7.5. In HEK293 cells that overexpressed SMase cDNA, the enzyme was localized to the mitochondrial fraction, whereas mutant proteins lacking MLS or both the MLS and the transmembrane domain were absent from the mitochondrial fraction. Endogenous SMase protein co-localized with a mitochondrial cytostaining marker. Using a protease protection assay, we found that SMase was distributed throughout the intermembrane space and/or the inner membrane of the mitochondrion. Furthermore, the overexpression of SMase in HEK293 cells induced ceramide generation and sphingomyelin hydrolysis in the mitochondrial fraction. Antisense phosphorothioate oligonucleotide-induced knockdown repressed ceramide generation and sphingomyelin hydrolysis in the mitochondrial fraction in zebrafish embryonic cells. These observations indicate that SMase catalyzes the hydrolysis of sphingomyelin and generates ceramide in mitochondria in fish cells.
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Affiliation(s)
- Takeshi Yabu
- From the National Research Institute of Fisheries Science, Yokohama, Kanagawa 236-8648, Japan
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Pavoine C, Pecker F. Sphingomyelinases: their regulation and roles in cardiovascular pathophysiology. Cardiovasc Res 2009; 82:175-83. [PMID: 19176603 DOI: 10.1093/cvr/cvp030] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sphingomyelinases (SMases) hydrolyse sphingomyelin, releasing ceramide and creating a cascade of bioactive lipids. These lipids include sphingosine and sphingosine-1-phosphate, all of which have a specific signalling capacity. Sphingomyelinase activation occurs in different cardiovascular system cell types, namely cardiac myocytes, endothelial and vascular smooth muscle cells, mediating cell proliferation, cell death, and contraction of cardiac and vascular myocytes. Three main types of SMases contribute to cardiovascular physiology: the lysosomal and secreted acidic SMases (L- and S-ASMases, respectively) and the membrane neutral SMase (NSMase). These three enzymes have common activators, including ischaemia/reperfusion stress and proinflammatory cytokines, but they differ in their enzymatic properties and subcellular locations that determine the final effect of enzyme activation. This review focuses on the recent advances in the understanding of ASMase and NSMase pathways and their specific contribution to cardiovascular pathophysiology. Current knowledge indicates that the inhibitors of the different SMase types are potential tools for the treatment of cardiovascular diseases. Acid SMase inhibitors could be tools against post-ischaemia reperfusion injury and in the treatment of atherosclerosis. Neutral SMase inhibitors could be tools for the treatment of atherosclerosis, heart failure, and age-related decline in vasomotion. However, the design of bioavailable and more specific SMase-type inhibitors remains a challenge.
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Corcoran CA, He Q, Ponnusamy S, Ogretmen B, Huang Y, Sheikh MS. Neutral sphingomyelinase-3 is a DNA damage and nongenotoxic stress-regulated gene that is deregulated in human malignancies. Mol Cancer Res 2008; 6:795-807. [PMID: 18505924 DOI: 10.1158/1541-7786.mcr-07-2097] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, we report the characterization of a novel genotoxic and nongenotoxic stress-regulated gene that we had previously named as SKNY. Our results indicate that SKNY encodes the recently identified neutral sphingomyelinase-3 (nSMase3; hereafter SKNY is referred to as nSMase3). Examination of nSMase3 subcellular distribution reveals nSMase3 to localize to the endoplasmic reticulum (ER), and deletion of a COOH-terminal region containing its putative transmembrane domain and ER targeting signal partly alters its compartmentalization to the ER. Treatment with genotoxic Adriamycin and nongenotoxic tumor necrosis factor-alpha up-regulates endogenous nSMase3 expression, albeit with different kinetics. Tumor necrosis factor-alpha up-regulates nSMase3 expression within 2 h that lasts beyond 24 h and declines to control levels by 36 h. Adriamycin up-regulation of nSMase3 is transient, occurs within 30 min, and declines to control levels by 120 min. Prolonged treatment with Adriamycin by 24 h and beyond, however, causes a down-regulation in nSMase3 expression. Activation of wild-type p53 also down-regulates nSMase3 expression, suggesting that DNA damage-mediated nSMase3 down-regulation seems to occur partly through the tumor suppressor p53. Overexpression of exogenous nSMase3 sensitizes cells to Adriamycin-induced cell killing, a finding consistent with the proposed proapoptotic role of nSMase enzymes and nSMase-generated ceramide. We further investigated nSMase3 expression in various human malignancies and found its expression to be deregulated in several types of primary tumors when compared with their matching normal tissues. Collectively, our results have identified nSMase3 to be an important molecule that is linked to tumorigenesis and cellular stress response.
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Affiliation(s)
- Chad A Corcoran
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA
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Yabu T, Imamura S, Yamashita M, Okazaki T. Identification of Mg2+ -dependent neutral sphingomyelinase 1 as a mediator of heat stress-induced ceramide generation and apoptosis. J Biol Chem 2008; 283:29971-82. [PMID: 18678863 DOI: 10.1074/jbc.m805402200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Neutral sphingomyelinases (SMases) are involved in the induction of ceramide-mediated proapoptotic signaling under heat stress conditions. Although ceramide is an important mediator of apoptosis, the neutral SMase that is activated under heat stress has not been identified. In this study, we cloned an Mg(2+)-dependent neutral SMase from a zebrafish embryonic cell cDNA library using an Escherichia coli expression-cloning vector. Screening of the clones using an SMase activity assay with C(6)-7-nitro-2-1,3-benzoxadiazol-4-yl-sphingomyelin as the substrate resulted in the isolation of one neutral SMase cDNA clone. This cDNA encoded a polypeptide of 420 amino acids (putative molecular weight: 46,900) containing two predicted transmembrane domains in its C-terminal region. The cloned neutral SMase 1 acted as a mediator of stress-induced apoptosis. Bacterially expressed recombinant neutral SMase 1 hydrolyzed [choline-methyl-(14)C]sphingomyelin optimally at pH 7.5 in the presence of an Mg(2+) ion. In zebrafish embryonic cells, the endogenous SMase enzyme was localized in the microsomal fraction. In FLAG-tagged SMase-overexpressing cells, neutral SMase 1 colocalized with a Golgi marker in a cytochemical analysis. Inactivation of the enzyme by an antisense phosphorothioate oligonucleotide repressed the induction of ceramide generation, caspase-3 activation, and apoptotic cell death by heat stress. Thus, neutral SMase 1 participates in an inducible ceramide-mediating, proapoptotic signaling pathway that operates in heat-induced apoptosis in zebrafish embryonic cells.
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Affiliation(s)
- Takeshi Yabu
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan.
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Mutations in the neutral sphingomyelinase gene SMPD3 implicate the ceramide pathway in human leukemias. Blood 2008; 111:4716-22. [PMID: 18299447 DOI: 10.1182/blood-2007-10-113068] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Ceramide is a lipid second messenger derived from the hydrolysis of sphingomyelin by sphingomyelinases (SMases) and implicated in diverse cellular responses, including growth arrest, differentiation, and apoptosis. Defects in the neutral SMase (nSMase) gene Smpd3, the primary regulator of ceramide biosynthesis, are responsible for developmental defects of bone; regulation of ceramide levels have been implicated in macrophage differentiation, but this pathway has not been directly implicated in human cancer. In a genomic screen for gene copy losses contributing to tumorigenesis in a mouse osteosarcoma model, we identified a somatic homozygous deletion specifically targeting Smpd3. Reconstitution of SMPD3 expression in mouse tumor cells lacking the endogenous gene enhanced tumor necrosis factor (TNF)-induced reduction of cell viability. Nucleotide sequencing of the highly conserved SMPD3 gene in a large panel of human cancers revealed mutations in 5 (5%) of 92 acute myeloid leukemias (AMLs) and 8 (6%) of 131 acute lymphoid leukemias (ALLs), but not in other tumor types. In a subset of these mutations, functional analysis indicated defects in protein stability and localization. Taken together, these observations suggest that disruption of the ceramide pathway may contribute to a subset of human leukemias.
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Sabourdy F, Kedjouar B, Sorli SC, Colié S, Milhas D, Salma Y, Levade T. Functions of sphingolipid metabolism in mammals--lessons from genetic defects. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:145-83. [PMID: 18294974 DOI: 10.1016/j.bbalip.2008.01.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 01/15/2008] [Accepted: 01/15/2008] [Indexed: 01/23/2023]
Abstract
Much is known about the pathways that control the biosynthesis, transport and degradation of sphingolipids. During the last two decades, considerable progress has been made regarding the roles this complex group of lipids play in maintaining membrane integrity and modulating responses to numerous signals. Further novel insights have been provided by the analysis of newly discovered genetic diseases in humans as well as in animal models harboring mutations in the genes whose products control sphingolipid metabolism and action. Through the description of the phenotypic consequences of genetic defects resulting in the loss of activity of the many proteins that synthesize, transport, bind, or degrade sphingolipids, this review summarizes the (patho)physiological functions of these lipids.
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Stoffel W, Jenke B, Holz B, Binczek E, Günter RH, Knifka J, Koebke J, Niehoff A. Neutral sphingomyelinase (SMPD3) deficiency causes a novel form of chondrodysplasia and dwarfism that is rescued by Col2A1-driven smpd3 transgene expression. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:153-61. [PMID: 17591962 PMCID: PMC1941606 DOI: 10.2353/ajpath.2007.061285] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neutral sphingomyelinase SMPD3 (nSMase2), a sphingomyelin phosphodiesterase, resides in the Golgi apparatus and is ubiquitously expressed. Gene ablation of smpd3 causes a generalized prolongation of the cell cycle that leads to late embryonic and juvenile hypoplasia because of the SMPD3 deficiency in hypothalamic neurosecretory neurons. We show here that this novel form of combined pituitary hormone deficiency is characterized by the perturbation of the hypothalamus-pituitary growth axis, associated with retarded chondrocyte development and enchondral ossification in the epiphyseal growth plate. To study the contribution by combined pituitary hormone deficiency and by the local SMPD3 deficiency in the epiphyseal growth plate to the skeletal phenotype, we introduced the full-length smpd3 cDNA transgene under the control of the chondrocyte-specific promoter Col2a1. A complete rescue of the smpd3(-/-) mouse from severe short-limbed skeletal dysplasia was achieved. The smpd3(-/-) mouse shares its dwarf and chondrodysplasia phenotype with the most common form of human achondrodysplasia, linked to the fibroblast-growth-factor receptor 3 locus, not linked to deficits in the hypothalamic-pituitary epiphyseal growth plate axis. The rescue of smpd3 in vivo has implications for future research into dwarfism and, particularly, growth and development of the skeletal system and for current screening and future treatment of combined dwarfism and chondrodysplasia.
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Affiliation(s)
- Wilhelm Stoffel
- University of Cologne, Laboratory of Molecular Neurosciences, Joseph Stelzmannstrasse 52, Cologne, Germany 50931, USA.
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Zeidan YH, Hannun YA. Translational aspects of sphingolipid metabolism. Trends Mol Med 2007; 13:327-36. [PMID: 17588815 DOI: 10.1016/j.molmed.2007.06.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 06/01/2007] [Accepted: 06/12/2007] [Indexed: 12/14/2022]
Abstract
Sphingolipids, a major class of lipids in cell membranes, play diverse roles in biological processes. As bioactive and structural molecules, they have signaling activities and biophysical properties that are essential for regulating various cellular, tissue and systemic functions. Moreover, sphingolipids are receiving increasing attention as contributors to the pathogenesis of several human disorders, including, cancer, inflammation and neurological, immune and metabolic disorders. Small-molecule inhibitors and monoclonal antibodies that target sphingolipid metabolism recently enabled giant strides toward treatment of malignant and autoimmune disorders. Here, we review the emerging roles of sphingolipids in disease pathogenesis and the attendant possibilities for sphingolipid-based therapeutics.
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Affiliation(s)
- Youssef H Zeidan
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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Abstract
PURPOSE OF REVIEW Membrane lipids play important roles in signaling reactions. They are involved in most if not all cellular signaling cascades and in a wide variety of tissue and cell types. The purpose of this review is to highlight major pathways of signaling originating in membrane lipids. Details of lipid metabolism, and its relation to protein function, will thus advance understanding of the role of lipids in health and disease. RECENT FINDINGS Major classes of lipids including glycerophospholipids, their metabolites (eicosanoids, endocannabinoids), and sphingolipids have recently generated interest in the field of signal transduction. These lipids are tightly regulated and have an impact on various physiological functions. Importantly, aberrant lipid metabolism often leads to onset of pathology, and thus the precise balance of signaling lipids and their effectors can serve as biomarkers. SUMMARY Membrane lipids form precursors for second messengers and functional assembly matrices on membrane domains during cellular stimulation. Many of these modifications are rapid reactions at lipid headgroups. Metabolism of the fatty acyl portion of membrane lipids leads to the generation of a bewildering complexity of lipid mediators with extended effects in space and time.
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Affiliation(s)
- Aaron Z Fernandis
- National University of Singapore, Yong Loo Lin School of Medicine, Department of Biochemistry and Department of Biological Sciences, Centre for Life Sciences, Singapore
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Puglielli L. Aging of the brain, neurotrophin signaling, and Alzheimer's disease: is IGF1-R the common culprit? Neurobiol Aging 2007; 29:795-811. [PMID: 17313996 PMCID: PMC2387053 DOI: 10.1016/j.neurobiolaging.2007.01.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 09/21/2006] [Accepted: 01/13/2007] [Indexed: 12/26/2022]
Abstract
The last decade has revealed that the lifespan of an organism can be modulated by the signaling pathway that acts downstream of the insulin/insulin-like growth factor 1 receptors (IR/IGF1-R), indicating that there is a "program" that drives the process of aging. New results have now linked the same pathway to the neurogenic capacities of the aging brain, to neurotrophin signaling, and to the molecular pathogenesis of Alzheimer's disease. Therefore, a common signaling cascade now seems to link aging to age-associated pathologies of the brain, suggesting that pharmacologic approaches aimed at the modulation of this pathway can serve to delay the onset of age-associated disorders and improve the quality of life. Work from a wide range of fields performed with different approaches has already identified some of the signaling molecules that act downstream of IGF1-R, and has revealed that a delicate checkpoint exists to balance excessive growth/"immortality" and reduced growth/"senescence" of a cell. Future research will determine how far the connection goes and how much of it we can influence.
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Affiliation(s)
- Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, and Geriatric Research Education Clinical Center, VA Medical Center, VAH-GRECC 11G, 2500 Overlook Terrace, Madison, WI 53705, USA.
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Tani M, Hannun YA. Neutral sphingomyelinase 2 is palmitoylated on multiple cysteine residues. Role of palmitoylation in subcellular localization. J Biol Chem 2007; 282:10047-10056. [PMID: 17272284 DOI: 10.1074/jbc.m611249200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The neutral sphingomyelinases (nSMases) are considered major candidates for mediating the stress-induced production of ceramide. nSMase2, which has two hydrophobic segments near the NH(2)-terminal region, has been reported to be located at the plasma membrane and play important roles in ceramide-mediated signaling. In this study, we found that nSMase2 is palmitoylated on multiple cysteine residues via thioester bonds. Site-directed mutagenesis of cysteine residues to alanine indicated that two cysteine clusters of the enzyme are multiply palmitoylated; one cluster is located between the two hydrophobic segments, and the second one is located in the middle of the catalytic region of the protein. When overexpressed in the confluent phase of MCF-7 cells, wild-type nSMase2 was strictly localized in the plasma membranes, and the cysteine mutants of each palmitoylated cysteine cluster were seen not only at the plasma membrane but also in some punctate structures. Furthermore, mutation of all potential palmitoylation sites resulted in a dramatic reduction in the plasma membrane distribution and an increase in the punctate structures. The palmitoylation-deficient mutant was directed to lysosomes and rapidly degraded. Palmitoylation had no effect on enzyme activity but affected membrane-association properties of the protein. Finally, the catalytic region of nSMase2 where palmitoylation occurs was found to be localized at the inner leaflet of the plasma membrane. In summary, the results from this study reveal for the first time the palmitoylation of nSMase2 via thioester bonds and its importance in the subcellular localization and stability of this protein.
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Affiliation(s)
- Motohiro Tani
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Yusuf A Hannun
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425.
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Clarke CJ, Hannun YA. Neutral sphingomyelinases and nSMase2: Bridging the gaps. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1893-901. [PMID: 16938269 DOI: 10.1016/j.bbamem.2006.06.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Revised: 06/09/2006] [Accepted: 06/12/2006] [Indexed: 11/30/2022]
Abstract
There is strong evidence indicating a role for ceramide as a second messenger in processes such as apoptosis, cell growth and differentiation, and cellular responses to stress. Ceramide formation from the hydrolysis of sphingomyelin is considered to be a major pathway of stress-induced ceramide production with magnesium-dependent neutral sphingomyelinase (N-SMase) identified as a prime candidate in this pathway. The recent cloning of a mammalian N-SMase-nSMase2- and generation of nSMase2 knockout/mutant mice have now provided vital tools with which to further study the regulation and roles of this enzyme in both a physiological and pathological context. In the present review, we summarize current knowledge on N-SMase relating this to what is known about nSMase2. We also discuss the future areas of nSMase2 research important for molecular understanding of this enzyme and its physiological roles.
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Affiliation(s)
- Christopher J Clarke
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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Ng CG, Griffin DE. Acid sphingomyelinase deficiency increases susceptibility to fatal alphavirus encephalomyelitis. J Virol 2006; 80:10989-99. [PMID: 16943298 PMCID: PMC1642146 DOI: 10.1128/jvi.01154-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2006] [Accepted: 08/23/2006] [Indexed: 01/31/2023] Open
Abstract
Sindbis virus (SV), an enveloped virus with a single-stranded, plus-sense RNA genome, is the prototype alphavirus in the Togaviridae family. In mice, SV infects neurons and can cause apoptosis of immature neurons. Sphingomyelin (SM) is the most prevalent cellular sphingolipid, is particularly abundant in the nervous systems of mammals, and is required for alphavirus fusion and entry. The level of SM is tightly regulated by sphingomyelinases. A defect in acid sphingomyelinase (ASMase) results in SM storage and subsequent intracellular accumulation of SM. To better understand the role of the SM pathway in SV pathogenesis, we have characterized SV infection of transgenic mice deficient in the ASMase gene. ASMase knockout (ASM-KO) mice were more susceptible to SV infection than wild-type (WT) or heterozygous (Het) animals. Titers of SV were higher in the brains of ASM-KO mice than in the brains of WT mice. More SV RNA was detected by in situ hybridization, more SV protein was detected by immunohistochemistry, and more terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling-positive cells were present in the cortex and hippocampus of ASM-KO mice than in those of WT or Het mice. Interleukin-6 (IL-6), but not IL-1beta or tumor necrosis factor alpha, was elevated in infected ASM-KO mice compared to levels in WT or Het mice, but studies with IL-6-KO mice and recombinant SV expressing IL-6 showed no role for IL-6 in fatal disease. Together these data indicate that the increase in susceptibility of ASM-KO mice to SV infection was the result of more-rapid replication and spread of SV in the nervous system and increased neuronal death.
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Affiliation(s)
- Ching G Ng
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
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Davis CN, Tabarean I, Gaidarova S, Behrens MM, Bartfai T. IL-1beta induces a MyD88-dependent and ceramide-mediated activation of Src in anterior hypothalamic neurons. J Neurochem 2006; 98:1379-89. [PMID: 16771830 DOI: 10.1111/j.1471-4159.2006.03951.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The proinflammatory cytokine interleukin 1beta (IL-1beta), acting at IL-1R1 receptors, affects neuronal signaling under both physiological and pathophysiological conditions. The molecular mechanism of the rapid synaptic actions of IL-1beta in neurons is not known. We show here that within minutes of IL-1beta exposure, the firing rate of anterior hypothalamic (AH) neurons in culture was inhibited. This effect was prevented by pre-exposure of the cells to the Src family inhibitor, PP2, suggesting the involvement of Src in the hyperpolarizing effects of IL-1beta. The IL-1beta stimulation of neurons induced a rapid increase in the phosphorylation of the tyrosine kinase Src and kinase suppressor of Ras (ceramide activated protein kinase (CAPK)/KSR) in neurons grown on glia from IL-1RI(-/-) mice. These effects of IL-1beta were dependent on the association of the cytosolic adaptor protein, MyD88, to the IL-1 receptor, and on the activation of the neutral sphingomyelinase, leading to production of ceramide. A cell-permeable analog of ceramide mimicked the effects of IL-1beta on the cultured AH neurons. These results suggest that ceramide may be the second messenger of the fast IL-1beta actions in AH neurons, and that this IL-1beta/ceramide pathway may underlie the fast non-transcription-dependent, electrophysiological effects of IL-1beta observed in AH neurons in vivo.
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Affiliation(s)
- Christopher N Davis
- The Harold L. Dorris Neurological Research Institute and Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California 92037, USA
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Won JS, Singh I. Sphingolipid signaling and redox regulation. Free Radic Biol Med 2006; 40:1875-88. [PMID: 16716889 DOI: 10.1016/j.freeradbiomed.2006.01.035] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 01/25/2006] [Accepted: 01/28/2006] [Indexed: 01/09/2023]
Abstract
Sphingolipids including ceramide and its derivatives such as ceramide-1-phosphate, glycosyl-ceramide, and sphinogosine (-1-phosphate) are now recognized as novel intracellular signal mediators for regulation of inflammation, apoptosis, proliferation, and differentiation. One of the important and regulated steps in these events is the generation of these sphingolipids via hydrolysis of sphingomyelin through the action of sphingomyelinases (SMase). Several lines of evidence suggest that reactive oxygen species (ROS; O2-, H2O2, and OH-,) and reactive nitrogen species (RNS; NO, and ONOO-) and cellular redox potential, which is mainly regulated by cellular glutathione (GSH), are tightly linked to the regulation of SMase activation. On the other hand, sphingolipids are also known to play an important role in maintaining cellular redox homeostasis through regulation of NADPH oxidase, mitochondrial integrity, and antioxidant enzymes. Therefore, this paper reviews the relationship between cellular redox and sphingolipid metabolism and its biological significance.
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Affiliation(s)
- Je-Seong Won
- Division of Developmental Neurological Disorder in Charles P. Darby Children's Research Institute, Department of Pediatrics, Medical University of South Carolina, Room 505, 171 Ashley Avenue, Charleston, SC 29425, USA
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Krut O, Wiegmann K, Kashkar H, Yazdanpanah B, Krönke M. Novel tumor necrosis factor-responsive mammalian neutral sphingomyelinase-3 is a C-tail-anchored protein. J Biol Chem 2006; 281:13784-13793. [PMID: 16517606 DOI: 10.1074/jbc.m511306200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two genes encoding neutral sphingomyelinases-1 and -2 (sphingomyelin phosphodiesterases-2 and -3) have been recently identified that hydrolyze sphingomyelin to phosphorylcholine and ceramide. Data bank searches using a peptide sequence derived from a previously purified bovine neutral sphingomyelinase (nSMase) allowed us to identify a cDNA encoding a novel human sphingomyelinase, nSMase3, that shows only a little homology to nSMase1 and -2. nSMase3 was biochemically characterized by overexpression in a yeast strain, JK9-3ddeltaIsc1p, lacking endogenous SMase activity. Similar to nSMase2, nSMase3 is Mg2+-dependent and shows optimal activity at pH 7, which is enhanced in the presence of phosphatidylserine and inhibited by scyphostatin. nSMase3 is ubiquitously expressed as a 4.6-kb mRNA species. nSMase3 lacks an N-terminal signal peptide, yet contains a 23-amino-acid transmembrane domain close to the C terminus, which is indicative for the family of C-tail-anchored integral membrane proteins. Cellular localization studies with hemagglutinin-tagged nSMase3 demonstrated colocalization with markers of the endoplasmic reticulum as well as with Golgi markers. Tumor necrosis factor stimulates rapid activation of nSMase3 in MCF7 cells with peak activity at 1.5 min, which was impaired by expression of dominant negative FAN.
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Affiliation(s)
- Oleg Krut
- Institute for Medical Microbiology, Immunology, and Hygiene, Center for Molecular Medicine-Cologne, University of Cologne, 50935 Köln, Germany
| | - Katja Wiegmann
- Institute for Medical Microbiology, Immunology, and Hygiene, Center for Molecular Medicine-Cologne, University of Cologne, 50935 Köln, Germany
| | - Hamid Kashkar
- Institute for Medical Microbiology, Immunology, and Hygiene, Center for Molecular Medicine-Cologne, University of Cologne, 50935 Köln, Germany
| | - Benjamin Yazdanpanah
- Institute for Medical Microbiology, Immunology, and Hygiene, Center for Molecular Medicine-Cologne, University of Cologne, 50935 Köln, Germany
| | - Martin Krönke
- Institute for Medical Microbiology, Immunology, and Hygiene, Center for Molecular Medicine-Cologne, University of Cologne, 50935 Köln, Germany.
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Stoffel W, Jenke B, Blöck B, Zumbansen M, Koebke J. Neutral sphingomyelinase 2 (smpd3) in the control of postnatal growth and development. Proc Natl Acad Sci U S A 2005; 102:4554-9. [PMID: 15764706 PMCID: PMC555473 DOI: 10.1073/pnas.0406380102] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Neutral sphingomyelinases sphingomyelin phosphodiesterase (SMPD)2 and -3 hydrolyze sphingomyelin to phosphocholine and ceramide. smpd2 is expressed ubiquitously, and smpd3 is expressed predominantly in neurons of the CNS. Their activation and the functions of the released ceramides have been associated with signaling pathways in cell growth, differentiation, and apoptosis. However, these cellular responses remain poorly understood. Here we describe the generation and characterization of the smpd3(-/-) and smpd2(-/-)smpd3(-/-) double mutant mouse, which proved to be devoid of neutral sphingomyelinase activity. SMPD3 plays a pivotal role in the control of late embryonic and postnatal development: the smpd3-null mouse develops a novel form of dwarfism and delayed puberty as part of a hypothalamus-induced combined pituitary hormone deficiency. Our studies suggest that SMPD3 is segregated into detergent-resistant subdomains of Golgi membranes of hypothalamic neurosecretory neurons, where its transient activation modifies the lipid bilayer, an essential step in the Golgi secretory pathway. The smpd3(-/-) mouse might mimic a form of human combined pituitary hormone deficiency.
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Affiliation(s)
- Wilhelm Stoffel
- Laboratory of Molecular Neurosciences, Center of Molecular Medicine, Center of Biochemistry, Faculty of Medicine, University of Cologne, D-50931 Cologne, Germany.
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Karakashian AA, Giltiay NV, Smith GM, Nikolova-Karakashian MN. Expression of neutral sphingomyelinase‐2 (NSMase‐2) in primary rat hepatocytes modulates IL‐β‐induced JNK activation. FASEB J 2004; 18:968-70. [PMID: 15059969 DOI: 10.1096/fj.03-0875fje] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neutral sphingomyelinase (NSMase) has been proposed to mediate interleukin (IL)-1beta signaling in liver. In this paper, we used adenovirus-mediated gene transfer to inducibly express FLAG-tagged mouse NSMase-2 in primary rat hepatocytes in order to further elucidate the molecular nature of the NSMase involved. Initial studies confirmed that the EST clone used in these experiments encoded a Mg2+-dependent NSMase. The in vitro activity of the heterologously expressed enzyme was inhibited in the presence of 0.5% Triton or 50 mM EDTA. In addition, the expression of this NSMase-2 clone in primary hepatocytes led to increased cellular levels of ceramide, indicating that the enzyme is active in situ. Immunofluorescence studies in Hep G2 cells infected with NSMase-2 expressing adenoviruses showed that the FLAG-tagged NSMase-2 was localized to the plasma membrane. Cell viability remained unchanged 72 h following infection and induction. The effect of NSMase-2 expression on IL-1beta-induced activation of c-Jun N-terminal kinase (JNK) was tested. Expression of NSMase-2 increased JNK phosphorylation between 1.5- and 2-fold over the basal level. Furthermore, NSMase-2 was found to strongly increase the ability of IL-1beta to phosphorylate JNK. This potentiation was mediated by a phosphatase from the PP2A family, possibly by modulating the phosphorylation pattern of IL-1beta receptor-associated kinase (IRAK). In conclusion, the data presented suggest that NSMase-2 could be involved in IL-1beta-induced JNK activation in hepatocytes.
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Affiliation(s)
- Alexander A Karakashian
- Department of Physiology, University of Kentucky, A. B. Chandler Medical Center, Lexington, Kentucky 40536, USA
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Testai FD, Landek MA, Dawson G. Regulation of sphingomyelinases in cells of the oligodendrocyte lineage. J Neurosci Res 2004; 75:66-74. [PMID: 14689449 DOI: 10.1002/jnr.10816] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Controversy exists regarding the nature of the "executioner" sphingomyelinase (SMase) in cells and its subcellular localization. A new fluorescence-based assay with the substrate 6-hexadecanoylamino-4-methylumbelliferyl-phosphorylcholine allowed rapid and reliable microassays of neutral (N) and acid (A) SMase activity in cell extracts from primary cultures of neonatal rat oligodendrocytes (OPC) and a human oligodendroglioma cell line (HOG). Total SMase activity was much higher in OPC than in HOG cells. Both staurosporine and tumor necrosis factor-alpha (TNF-alpha) induced apoptosis and activated NSMase in a multiphasic manner in both OPC and HOG cells. The increase in caspase 8 activity preceded the 1 hr peak of NSMase activation, which was followed by caspase 3 activation. In contrast, ASMase activity, which constituted >90% of the total SMase activity, was unresponsive to proapoptotic drugs. Neither reducing ASMase levels by 50% by pretreatment with desipramine nor inhibiting sphingolipid synthesis by 50% with fumonisin B1 had any effect on cell death. Isolation of sphingolipid-rich plasma membrane microdomains (rafts) from the cells by sucrose density gradient ultracentrifugation revealed an enrichment of sphingomyelin, ceramide, and caspase 8. Proapoptotic drugs such as staurosporine promoted the translocation of NSMase to the raft fraction. In contrast, ASMase, other lysosomal hydrolases, and caspase 3 remained absent from rafts even after staurosporine treatment. The staurosporine-induced concomitant increase of ceramide in the raft fraction and caspase 3 in the cytosol could be mimicked by the addition of exogenous bacterial SMase. We conclude that caspase 8 activates NSMase in rafts in oligodendrocytes and that the downstream apoptotic signal is via caspase 3.
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Affiliation(s)
- F D Testai
- Departments of Pediatrics, Biochemistry, and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA
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Marchesini N, Luberto C, Hannun YA. Biochemical properties of mammalian neutral sphingomyelinase 2 and its role in sphingolipid metabolism. J Biol Chem 2003; 278:13775-83. [PMID: 12566438 DOI: 10.1074/jbc.m212262200] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neutral sphingomyelinase (N-SMase) is one of the key enzymes involved in the generation of ceramide; however, the gene(s) encoding for the mammalian N-SMase is still not well defined. Previous studies on the cloned nSMase1 had shown that the protein acts primarily as lyso-platelet-activating factor-phospholipase C. Recently the cloning of another putative N-SMase, nSMase2, was reported. In this study, biochemical characterization of the mouse nSMase2 was carried out using the overexpressed protein in yeast cells in which the inositol phosphosphingolipid phospholipase C (Isc1p) was deleted. N-SMase activity was dependent on Mg(2+) and was activated by phosphatidylserine and inhibited by GW4869. The ability of nSMase2 to recognize endogenous sphingomyelin (SM) as substrate was investigated by overexpressing nSMase2 in MCF7 cells. Mass measurements showed a 40% decrease in the SM levels in the overexpressor cells, and labeling studies demonstrated that nSMase2 accelerated SM catabolism. Accordingly, ceramide measurement showed a 60 +/- 15% increase in nSMase2-overexpressing cells compared with the vector-transfected MCF7. The role of nSMase2 in cell growth was next investigated. Stable overexpression of nSMase2 resulted in a 30-40% decrease in the rate of growth at the late exponential phase. Moreover, tumor necrosis factor induced approximately 50% activation of nSMase2 in MCF7 cells overexpressing the enzyme, demonstrating that nSMase2 is a tumor necrosis factor-responsive enzyme. In conclusion, these results 1) show that nSMase2 is a structural gene for nSMase, 2) suggest that nSMase2 acts as a bona fide N-SMase in cells, and 3) implicate nSMase2 in the regulation of cell growth and cell signaling.
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Affiliation(s)
- Norma Marchesini
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425, USA
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Kilkus J, Goswami R, Testai FD, Dawson G. Ceramide in rafts (detergent-insoluble fraction) mediates cell death in neurotumor cell lines. J Neurosci Res 2003; 72:65-75. [PMID: 12645080 DOI: 10.1002/jnr.10549] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Detergent-resistant lipid microdomains (Rafts) were isolated from human oligodendroglioma (HOG), human neuroblastoma (LA-N-5), and immortalized dorsal root ganglion (F-11) cell lines by sucrose-density gradient ultracentrifugation and shown to be enriched in cholesterol, sphingomyelin, and ceramide. [(3)H]palmitate labeling allowed the Raft fraction to be easily identified as a sharp peak of (3)H radioactivity in the 5-30% sucrose interphase. Treatment of [(3)H]palmitate-labeled cells with staurosporine (to activate caspase 8 and induce apoptosis) or exogenous sphingomyelinase specifically increased the [(3)H]ceramide content of the Raft fraction. Depletion of cholesterol with beta-methylcyclodextran decreased Raft formation and partially blocked staurosporine-induced apoptosis. Similarly, treatment of cells with Fumonisin B1 to inhibit de novo sphingolipid synthesis by 50% reduced the labeling of the Raft fraction and partially blocked staurosporine-induced apoptosis. Staurosporine treatment activated neutral sphingomyelinase but had no effect on acid sphingomyelinase activity or on other lysosomal hydrolases, such as alpha-L-fucosidase. Most of the neutral sphingomyelinase activity is in the Raft fraction, suggesting that the conversion of sphingomyelin to ceramide in Rafts is an important event in neural cell apoptosis.
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Affiliation(s)
- John Kilkus
- Departments of Pediatrics, Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 30637, USA
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Huwiler A, Pfeilschifter J. Nitric Oxide Signalling with a Special Focus on Lipid-Derived Mediators. Biol Chem 2003; 384:1379-89. [PMID: 14669981 DOI: 10.1515/bc.2003.154] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The ways in which cells communicate among each other concerns all aspects of biology, from developmental processes to diseases. Nitric oxide (NO) is one of the most remarkable and unusual regulatory molecules. It is a labile free radical gas that is not stored but generated on demand, and has been implicated in an extraordinarily diverse range of physiological and pathophysiological functions. The modulation of cell signalling by free radicals is an emerging area of research that provides insight into the orchestration of cell adaptation to a changing microenvironment. In a multicellular organism this serves to coordinate complex physiological responses, such as inflammation. Cell signalling is also accompanied by rapid remodelling of membrane lipids by activated lipases. The discovery that NO, which does not reversibly interact with membrane receptors like conventional hormones and growth factors, targets enzymes such as phospholipase A2, sphingomyelinases or ceramidases, has stimulated growing interest in the crosstalk between redox and lipid signalling.
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Affiliation(s)
- Andrea Huwiler
- Pharmazentrum Frankfurt, Klinikum der Johann-Wolfgang-Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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Josephs M, Katan M, Rodrigues-Lima F. Irreversible inactivation of magnesium-dependent neutral sphingomyelinase 1 (NSM1) by peroxynitrite, a nitric oxide-derived oxidant. FEBS Lett 2002; 531:329-34. [PMID: 12417336 DOI: 10.1016/s0014-5793(02)03551-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous results have indicated that the generation of ceramide by hydrolysis of sphingomyelin by magnesium-dependent neutral sphingomyelinase 1 (NSM1) is reversibly inhibited by hydrogen peroxide (H2O2) and oxidized glutathione (GSSG). This redox-dependent reversible regulation of NSM1 activity has been shown to involve the reversible formation and breakage of disulfide bonds. In this paper, we show that peroxynitrite, a nitric oxide-derived oxidant generated by SIN1, inactivates dose-dependently the NSM1 activity in an irreversible manner. In addition, we show that, in contrast to the reversible inhibition of NSM1 by H2O2 or GSSG which involves the formation of disulfide bonds, irreversible inactivation of this enzyme by peroxynitrite generated from SIN1 is likely due to definitive oxidative thiol modification. These results suggest that depending on the nature of the oxidative stress, the enzymatic activity of NSM1 could be reversibly or irreversibly inactivated.
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Affiliation(s)
- Michelle Josephs
- Protein Biochemistry Group, Cancer Research UK Centre for Cell and Molecular Biology, The Institute of Cancer Research, Chester Beatty Laboratories, London, UK
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Martín SF, Gómez-Díaz C, Navas P, Villalba JM. Ubiquinol inhibition of neutral sphingomyelinase in liver plasma membrane: specific inhibition of the Mg2+-dependent enzyme and role of isoprenoid chain. Biochem Biophys Res Commun 2002; 297:581-6. [PMID: 12270134 DOI: 10.1016/s0006-291x(02)02222-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this work, the specificity of ubiquinol as inhibitor of the neutral sphingomyelinases present at the plasma membrane (Mg(2+)-dependent and -independent) and structural requirements for such inhibition have been studied. Our results have shown that ubiquinol specifically inhibits Mg(2+)-dependent neutral sphingomyelinase activity in isolated liver plasma membranes, but no significant participation of the Mg(2+)-independent enzyme was observed. Both the reduction state of the (hydro)quinone ring and the length of the hydrophobic side chain were important determinants in neutral sphingomyelinase inhibition. Ubiquinols inhibited the nSMase more efficiently than ubiquinones, and hydrophobic homologs with six or nine isoprene units were the most effective inhibitors. Inhibition of nSMase by ubiquinols displayed similarities with inhibition by manumycin and the hydroquinones F11334's, suggesting that these compounds could act as structural analogs of ubiquinol. Beyond its participation in mitochondrial energy metabolism, and as antioxidant, this novel role for ubiquinol as a neutral sphingomyelinase inhibitor should be considered an important factor to regulate lipid signaling at the plasma membrane that could be related to its beneficial effects on cells, tissues, and organisms.
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Affiliation(s)
- Sergio F Martín
- Departamento de Biología Celular, Fisiología e Inmunología, Facultad de Ciencias, Universidad de Córdoba, Córdoba 14014, Spain
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