1
|
Xia X, He X, Zhao T, Yang J, Bi Z, Fu Q, Liu J, Ao D, Wei Y, Wei X. Inhibiting mtDNA-STING-NLRP3/IL-1β axis-mediated neutrophil infiltration protects neurons in Alzheimer's disease. Cell Prolif 2024; 57:e13529. [PMID: 37528567 PMCID: PMC10771109 DOI: 10.1111/cpr.13529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/08/2023] [Accepted: 07/11/2023] [Indexed: 08/03/2023] Open
Abstract
Neutrophil is a pathophysiological character in Alzheimer's disease. The pathogen for neutrophil activation in cerebral tissue is the accumulated amyloid protein. In our present study, neutrophils infiltrate into the cerebra in two models (transgenic model APP/PS1 and stereotactic injection model) and promote neuron apoptosis, releasing their cellular constituents, including mitochondria and mitochondrial DNA (mtDNA). We found that both Aβ1-42 and mtDNA could provoke neutrophil infiltration into the cerebra, and they had synergistic effects when they presented together. This neutrophillic neuroinflammation upregulates expressions of STING, NLRP3 and IL-1β. These inflammatory cytokines with mtDNA constitute the mtDNA-STING-NLRP3/IL-1β axis, which is the prerequisite for neutrophil infiltration. When any factor in this pathway is depleted, the migration of neutrophils into cerebral tissue is ceased, with neurons and cognitive function being protected. Thus, we provide a novel perspective to alleviate the progression of Alzheimer's disease.
Collapse
Affiliation(s)
- Xiangyu Xia
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Xuemei He
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Tingmei Zhao
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Jingyun Yang
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Zhenfei Bi
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Qianmei Fu
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Jian Liu
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Danyi Ao
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yuquan Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| | - Xiawei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China HospitalSichuan UniversityChengduSichuanChina
| |
Collapse
|
2
|
Chiang YF, Nguyen NTK, Hsia SM, Chen HY, Lin SH, Lin CI. Protective Potential of β-Hydroxybutyrate against Glucose-Deprivation-Induced Neurotoxicity Involving the Modulation of Autophagic Flux and the Monomeric Aβ Level in Neuro-2a Cells. Biomedicines 2023; 11:biomedicines11030698. [PMID: 36979677 PMCID: PMC10045359 DOI: 10.3390/biomedicines11030698] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
Hypoglycemia has been known as a potential contributory factor to neurodegenerative diseases, such as Alzheimer’s disease. There may be shared pathogenic mechanisms underlying both conditions, and the ketone body, β-hydroxybutyrate (BHB), as an alternative substrate for glucose may exert neuroprotection against hypoglycemia-induced injury. To investigate this, Neuro-2a cells were subjected to a 24 h period of glucose deprivation with or without the presence of BHB. Cell viability, reactive oxygen species (ROS) production, apoptosis, autophagy, and adenosine triphosphate (ATP) and beta-amyloid peptide (Aβ) levels were evaluated. The results show that Neuro-2a cells deprived of glucose displayed a significant loss of cell survival with a corresponding decrease in ATP levels, suggesting that glucose deprivation was neurotoxic. This effect was likely attributed to the diverse mechanisms including raised ROS, defective autophagic flux and reduced basal Aβ levels (particularly monomeric Aβ). The presence of BHB could partially protect against the loss of cell survival induced by glucose deprivation. The mechanisms underlying the neuroprotective actions of BHB might be mediated, at least in part, through restoring ATP, and modulating ROS production, autophagy flux efficacy and the monomeric Aβ level. Results imply that a possible link between the basal monomeric Aβ and glucose deprivation neurotoxicity, and treatments designed for the prevention of energy impairment, such as BHB, may be beneficial for rescuing surviving cells in relation to neurodegeneration.
Collapse
Affiliation(s)
- Yi-Fen Chiang
- School of Nutrition and Health Sciences, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
| | - Ngan Thi Kim Nguyen
- Programs of Nutrition Science, School of Life Science, National Taiwan Normal University, Taipei 10610, Taiwan
| | - Shih-Min Hsia
- School of Nutrition and Health Sciences, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
- School of Food Safety, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
- Graduate Institute of Metabolism and Obesity Sciences, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
- Nutrition Research Center, Taipei Medical University Hospital, Taipei 11031, Taiwan
| | - Hsin-Yuan Chen
- School of Nutrition and Health Sciences, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
| | - Shyh-Hsiang Lin
- School of Nutrition and Health Sciences, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
- School of Food Safety, College of Nutrition, Taipei Medical University, Taipei 11031, Taiwan
| | - Ching-I Lin
- Department of Nutrition and Health Sciences, Kainan University, Taoyuan 338, Taiwan
- Correspondence: ; Tel.: +886-3-341-2500 (ext. 6193); Fax: +886-3-270-5904
| |
Collapse
|
3
|
Bigi A, Cascella R, Fani G, Bernacchioni C, Cencetti F, Bruni P, Chiti F, Donati C, Cecchi C. Sphingosine 1-phosphate attenuates neuronal dysfunction induced by amyloid-β oligomers through endocytic internalization of NMDA receptors. FEBS J 2023; 290:112-133. [PMID: 35851748 PMCID: PMC10087929 DOI: 10.1111/febs.16579] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/24/2022] [Accepted: 07/18/2022] [Indexed: 01/14/2023]
Abstract
Soluble oligomers arising from the aggregation of the amyloid beta peptide (Aβ) have been identified as the main pathogenic agents in Alzheimer's disease (AD). Prefibrillar oligomers of the 42-residue form of Aβ (Aβ42 O) show membrane-binding capacity and trigger the disruption of Ca2+ homeostasis, a causative event in neuron degeneration. Since bioactive lipids have been recently proposed as potent protective agents against Aβ toxicity, we investigated the involvement of sphingosine 1-phosphate (S1P) signalling pathway in Ca2+ homeostasis in living neurons exposed to Aβ42 O. We show that both exogenous and endogenous S1P rescued neuronal Ca2+ dyshomeostasis induced by toxic Aβ42 O in primary rat cortical neurons and human neuroblastoma SH-SY5Y cells. Further analysis revealed a strong neuroprotective effect of S1P1 and S1P4 receptors, and to a lower extent of S1P3 and S1P5 receptors, which activate the Gi -dependent signalling pathways, thus resulting in the endocytic internalization of the extrasynaptic GluN2B-containing N-methyl-D-aspartate receptors (NMDARs). Notably, the S1P beneficial effect can be sustained over time by sphingosine kinase-1 overexpression, thus counteracting the down-regulation of the S1P signalling induced by Aβ42 O. Our findings disclose underlying mechanisms of S1P neuronal protection against harmful Aβ42 O, suggesting that S1P and its signalling axis can be considered promising targets for therapeutic approaches for AD.
Collapse
Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Caterina Bernacchioni
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Francesca Cencetti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Paola Bruni
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Chiara Donati
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| |
Collapse
|
4
|
Protective Effects and Mechanisms of Dendrobium nobile Lindl. Alkaloids on PC12 Cell Damage Induced by A β 25-35. Behav Neurol 2021; 2021:9990375. [PMID: 34447483 PMCID: PMC8384511 DOI: 10.1155/2021/9990375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/18/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022] Open
Abstract
Background Aβ deposition abnormally in the mitochondria can damage the mitochondrial respiratory chain and activate the mitochondrial-mediated apoptosis pathway, resulting in AD-like symptoms. Objective To observe the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) on Aβ25-35-induced oxidative stress and apoptosis in PC12 cells explore its possible protective mechanisms. Methods PC12 cells were treated with DNLA with different concentrations (0.035 mg/L, 0.3 mg/L, and 3.5 mg/L) for 6 h, followed by administration with Aβ25-35 (10 μM) for 24 h. MTT assay and flow cytometer observe the effect of DNLA on Aβ25-35-induced cytotoxicity and apoptosis of PC12 cell. Based on the mitochondrial apoptosis pathway to study the antiapoptotic effect of DNLA on this model and its relationship with oxidative stress, flow cytometer detected the level of reactive oxygen species (ROS), and ELISA kits were used to detect superoxide dismutase activity (SOD) and glutathione (GSH) content in cells. The JC-1 fluorescent staining observed the effect of DNLA on the mitochondrial membrane potential (MMP) with inverted immunofluorescence microscopy. Western blot was used to detect the levels of mitochondrial apoptosis pathway-related protein and its major downstream proteins Bax, Bcl-2, cleaved-caspase-9, and cleaved-caspase-3. Results DNLA can significantly improve the viability and apoptosis rate of PC12 cell damage induced by Aβ25-35. It also can restore the reduced intracellular ROS content and MMP, while SOD activity and GSH content increase significantly. The expression of apoptosis-related protein Bax, cleaved-caspase-9, and cleaved-caspase-3 decreased when the Bcl-2 protein expression was significantly increased. Conclusion These findings suggest that it can significantly inhibit the apoptosis of PC12 cell damage induced by Aβ25-35. The mechanism may reduce the level of cellular oxidative stress and thus inhibit the mitochondrial-mediated apoptosis pathway.
Collapse
|
5
|
Hao Y, Guo M, Feng Y, Dong Q, Cui M. Lysophospholipids and Their G-Coupled Protein Signaling in Alzheimer's Disease: From Physiological Performance to Pathological Impairment. Front Mol Neurosci 2020; 13:58. [PMID: 32351364 PMCID: PMC7174595 DOI: 10.3389/fnmol.2020.00058] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/24/2020] [Indexed: 12/21/2022] Open
Abstract
Lysophospholipids (LPLs) are bioactive signaling lipids that are generated from phospholipase-mediated hydrolyzation of membrane phospholipids (PLs) and sphingolipids (SLs). Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are two of the best-characterized LPLs which mediate a variety of cellular physiological responses via specific G-protein coupled receptor (GPCR) mediated signaling pathways. Considerable evidence now demonstrates the crucial role of LPA and S1P in neurodegenerative diseases, especially in Alzheimer’s disease (AD). Dysfunction of LPA and S1P metabolism can lead to aberrant accumulation of amyloid-β (Aβ) peptides, the formation of neurofibrillary tangles (NFTs), neuroinflammation and ultimately neuronal death. Summarizing LPA and S1P signaling profile may aid in profound health and pathological processes. In the current review, we will introduce the metabolism as well as the physiological roles of LPA and S1P in maintaining the normal functions of the nervous system. Given these pivotal functions, we will further discuss the role of dysregulation of LPA and S1P in promoting AD pathogenesis.
Collapse
Affiliation(s)
- Yining Hao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Min Guo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yiwei Feng
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiang Dong
- Department of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Mei Cui
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| |
Collapse
|
6
|
Abstract
There is substantial evidence that the enzymes, sphingosine kinase 1 and 2, which catalyse the formation of the bioactive lipid sphingosine 1-phosphate, are involved in pathophysiological processes. In this chapter, we appraise the evidence that both enzymes are druggable and describe how isoform-specific inhibitors can be developed based on the plasticity of the sphingosine-binding site. This is contextualised with the effect of sphingosine kinase inhibitors in cancer, pulmonary hypertension, neurodegeneration, inflammation and sickling.
Collapse
Affiliation(s)
- Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde , Glasgow, Scotland, UK
| | - David R Adams
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, Scotland, UK
| | - Nigel J Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde , Glasgow, Scotland, UK.
| |
Collapse
|
7
|
Pramipexole and Fingolimod exert neuroprotection in a mouse model of Parkinson's disease by activation of sphingosine kinase 1 and Akt kinase. Neuropharmacology 2018; 135:139-150. [DOI: 10.1016/j.neuropharm.2018.02.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 02/14/2018] [Accepted: 02/22/2018] [Indexed: 12/14/2022]
|
8
|
Cao M, Ji C, Zhou Y, Huang W, Ni W, Tong X, Wei JF. Sphingosine kinase inhibitors: A patent review. Int J Mol Med 2018; 41:2450-2460. [PMID: 29484372 DOI: 10.3892/ijmm.2018.3505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/30/2018] [Indexed: 11/05/2022] Open
Abstract
Sphingosine kinases (SphKs) catalyze the conversion of the sphingosine to the promitogenic/migratory product, sphingosine-1-phosphate (S1P). SphK/S1P pathway has been linked to the progression of cancer and various other diseases including allergic inflammatory disease, cardiovascular diseases, rejection after transplantation, the central nervous system, and virus infections. Therefore, SphKs represent potential new targets for developing novel therapeutics for these diseases. The history and development of SphK inhibitors are discussed, summarizing SphK inhibitors by their structures, and describing some applications of SphK inhibitors. We concluded: i) initial SphK inhibitors based on sphingosine have low specificity with several important off-targets. Identification the off-targets that would work synergistically with SphKs, and developing compounds that target the unique C4 domain of SphKs should be the focus of future studies. ii) The modifications of SphK inhibitors, which are devoted to increasing the selectivity to one of the two isoforms, now focus on the alkyl length, the spacer between the head and linker rings, and the insertion and the position of lipidic group in tail region. iii) SphK/S1P signaling pathway holds therapeutic values for many diseases. To find the exact function of each isoform of SphKs increasing the number of SphK inhibitor clinical trials is necessary.
Collapse
Affiliation(s)
- Mengda Cao
- Department of Geriatrics, Beijing Hospital, National Center of Gerontology, Dongcheng, Beijing 100730, P.R. China
| | - Chunmei Ji
- Research Division of Clinical Pharmacology, Τhe First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Yanjun Zhou
- Research Division of Clinical Pharmacology, Τhe First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Wen Huang
- Research Division of Clinical Pharmacology, Τhe First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Weiwei Ni
- Research Division of Clinical Pharmacology, Τhe First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Xunliang Tong
- Department of Geriatrics, Beijing Hospital, National Center of Gerontology, Dongcheng, Beijing 100730, P.R. China
| | - Ji-Fu Wei
- Research Division of Clinical Pharmacology, Τhe First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| |
Collapse
|
9
|
Pyne S, Adams DR, Pyne NJ. Sphingosine 1-phosphate and sphingosine kinases in health and disease: Recent advances. Prog Lipid Res 2016; 62:93-106. [PMID: 26970273 DOI: 10.1016/j.plipres.2016.03.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 12/24/2022]
Abstract
Sphingosine kinases (isoforms SK1 and SK2) catalyse the formation of a bioactive lipid, sphingosine 1-phosphate (S1P). S1P is a well-established ligand of a family of five S1P-specific G protein coupled receptors but also has intracellular signalling roles. There is substantial evidence to support a role for sphingosine kinases and S1P in health and disease. This review summarises recent advances in the area in relation to receptor-mediated signalling by S1P and novel intracellular targets of this lipid. New evidence for a role of each sphingosine kinase isoform in cancer, the cardiovascular system, central nervous system, inflammation and diabetes is discussed. There is continued research to develop isoform selective SK inhibitors, summarised here. Analysis of the crystal structure of SK1 with the SK1-selective inhibitor, PF-543, is used to identify residues that could be exploited to improve selectivity in SK inhibitor development for future therapeutic application.
Collapse
Affiliation(s)
- Susan Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow, G4 0RE, Scotland, UK.
| | - David R Adams
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK.
| | - Nigel J Pyne
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St, Glasgow, G4 0RE, Scotland, UK.
| |
Collapse
|
10
|
Ghasemi R, Dargahi L, Ahmadiani A. Integrated sphingosine-1 phosphate signaling in the central nervous system: From physiological equilibrium to pathological damage. Pharmacol Res 2016; 104:156-64. [DOI: 10.1016/j.phrs.2015.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 11/14/2015] [Accepted: 11/15/2015] [Indexed: 01/09/2023]
|
11
|
Bhavanam NP, Failla A, Cho Y, Lockey RF, Kolliputi N. Commentary: The sphingosine kinase 1/sphingosine-1-phosphate pathway in pulmonary arterial hypertension. Front Pharmacol 2015; 6:229. [PMID: 26539114 PMCID: PMC4610201 DOI: 10.3389/fphar.2015.00229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/28/2015] [Indexed: 11/15/2022] Open
Affiliation(s)
- Naga P Bhavanam
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida Tampa, FL, USA
| | - Athena Failla
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida Tampa, FL, USA
| | - Young Cho
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida Tampa, FL, USA
| | - Richard F Lockey
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida Tampa, FL, USA
| | - Narasaiah Kolliputi
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida Tampa, FL, USA
| |
Collapse
|
12
|
The Molecular Mechanism of Amyloid β42 Peptide Toxicity: The Role of Sphingosine Kinase-1 and Mitochondrial Sirtuins. PLoS One 2015; 10:e0137193. [PMID: 26334640 PMCID: PMC4567180 DOI: 10.1371/journal.pone.0137193] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/22/2015] [Indexed: 12/14/2022] Open
Abstract
Our study focused on the relationship between amyloid β 1–42 (Aβ), sphingosine kinases (SphKs) and mitochondrial sirtuins in regulating cell fate. SphK1 is a key enzyme involved in maintaining sphingolipid rheostat in the brain. Deregulation of the sphingolipid metabolism may play a crucial role in the pathogenesis of Alzheimer’s disease (AD). Mitochondrial function and mitochondrial deacetylases, i.e. sirtuins (Sirt3,-4,-5), are also important for cell viability. In this study, we evaluated the interaction between Aβ1–42, SphKs and Sirts in cell survival/death, and we examined several compounds to indicate possible target(s) for a strategy protecting against cytotoxicity of Aβ1–42. PC12 cells were subjected to Aβ1–42 oligomers and SphK inhibitor SKI II for 24–96 h. Our data indicated that Aβ1–42 enhanced SphK1 expression and activity after 24 h, but down-regulated them after 96 h and had no effect on Sphk2. Aβ1–42 and SKI II induced free radical formation, disturbed the balance between pro- and anti-apoptotic proteins and evoked cell death. Simultaneously, up-regulation of anti-oxidative enzymes catalase and superoxide dismutase 2 was observed. Moreover, the total protein level of glycogen synthase kinase-3β was decreased. Aβ1–42 significantly increased the level of mitochondrial proteins: apoptosis-inducing factor AIF and Sirt3, -4, -5. By using several pharmacologically active compounds we showed that p53 protein plays a significant role at very early stages of Aβ1–42 toxicity. However, during prolonged exposure to Aβ1–42, the activation of caspases, MEK/ERK, and alterations in mitochondrial permeability transition pores were additional factors leading to cell death. Moreover, SphK product, sphingosine-1-phosphate (S1P), and Sirt activators and antioxidants, resveratrol and quercetin, significantly enhanced viability of cells subjected to Aβ1–42. Our data indicated that p53 protein and inhibition of SphKs may be early key events responsible for cell death evoked by Aβ1–42. We suggest that activation of S1P-dependent signalling and Sirts may offer a promising cytoprotective strategy.
Collapse
|