101
|
Abstract
Defects in autophagy have been linked to a wide range of medical illnesses, including cancer as well as infectious, neurodegenerative, inflammatory, and metabolic diseases. These observations have led to the hypothesis that autophagy inducers may prevent or treat certain clinical conditions. Lifestyle and nutritional factors, such as exercise and caloric restriction, may exert their known health benefits through the autophagy pathway. Several currently available FDA-approved drugs have been shown to enhance autophagy, and this autophagy-enhancing action may be repurposed for use in novel clinical indications. The development of new drugs that are designed to be more selective inducers of autophagy function in target organs is expected to maximize clinical benefits while minimizing toxicity. This Review summarizes the rationale and current approaches for developing autophagy inducers in medicine, the factors to be considered in defining disease targets for such therapy, and the potential benefits of such treatment for human health.
Collapse
|
102
|
Reidick C, El Magraoui F, Meyer HE, Stenmark H, Platta HW. Regulation of the Tumor-Suppressor Function of the Class III Phosphatidylinositol 3-Kinase Complex by Ubiquitin and SUMO. Cancers (Basel) 2014; 7:1-29. [PMID: 25545884 PMCID: PMC4381249 DOI: 10.3390/cancers7010001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/08/2014] [Indexed: 12/19/2022] Open
Abstract
The occurrence of cancer is often associated with a dysfunction in one of the three central membrane-involution processes—autophagy, endocytosis or cytokinesis. Interestingly, all three pathways are controlled by the same central signaling module: the class III phosphatidylinositol 3-kinase (PI3K-III) complex and its catalytic product, the phosphorylated lipid phosphatidylinositol 3-phosphate (PtdIns3P). The activity of the catalytic subunit of the PI3K-III complex, the lipid-kinase VPS34, requires the presence of the membrane-targeting factor VPS15 as well as the adaptor protein Beclin 1. Furthermore, a growing list of regulatory proteins associates with VPS34 via Beclin 1. These accessory factors define distinct subunit compositions and thereby guide the PI3K-III complex to its different cellular and physiological roles. Here we discuss the regulation of the PI3K-III complex components by ubiquitination and SUMOylation. Especially Beclin 1 has emerged as a highly regulated protein, which can be modified with Lys11-, Lys48- or Lys63-linked polyubiquitin chains catalyzed by distinct E3 ligases from the RING-, HECT-, RBR- or Cullin-type. We also point out other cross-links of these ligases with autophagy in order to discuss how these data might be merged into a general concept.
Collapse
Affiliation(s)
- Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum 44801, Germany.
| | - Fouzi El Magraoui
- Biomedical Research, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften-ISAS, Dortmund 44139, Germany.
| | - Helmut E Meyer
- Biomedical Research, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften-ISAS, Dortmund 44139, Germany.
| | - Harald Stenmark
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo 0310, Norway.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, Bochum 44801, Germany.
| |
Collapse
|
103
|
Gonfloni S. Defying c-Abl signaling circuits through small allosteric compounds. Front Genet 2014; 5:392. [PMID: 25429298 PMCID: PMC4228975 DOI: 10.3389/fgene.2014.00392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 10/25/2014] [Indexed: 11/13/2022] Open
Abstract
Many extracellular and intracellular signals promote the c-Abl tyrosine kinase activity. c-Abl in turn triggers a multitude of changes either in protein phosphorylation or in gene expression in the cell. Yet, c-Abl takes part in diverse signaling routes because of several domains linked to its catalytic core. Complex conformational changes turn on and off its kinase activity. These changes affect surface features of the c-Abl kinase and likely its capability to bind actin and/or DNA. Two specific inhibitors (ATP-competitive or allosteric compounds) regulate the c-Abl kinase through different mechanisms. NMR studies show that a c-Abl fragment (SH3-SH2-linker-SH1) adopts different conformational states upon binding to each inhibitor. This supports an unconventional use for allosteric compounds to unraveling physiological c-Abl signaling circuits.
Collapse
|
104
|
Lonskaya I, Hebron M, Chen W, Schachter J, Moussa C. Tau deletion impairs intracellular β-amyloid-42 clearance and leads to more extracellular plaque deposition in gene transfer models. Mol Neurodegener 2014; 9:46. [PMID: 25384392 PMCID: PMC4247762 DOI: 10.1186/1750-1326-9-46] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/21/2014] [Indexed: 01/02/2023] Open
Abstract
Background Tau is an axonal protein that binds to and regulates microtubule function. Hyper-phosphorylation of Tau reduces its binding to microtubules and it is associated with β-amyloid deposition in Alzheimer’s disease. Paradoxically, Tau reduction may prevent β-amyloid pathology, raising the possibility that Tau mediates intracellular Aβ clearance. The current studies investigated the role of Tau in autophagic and proteasomal intracellular Aβ1-42 clearance and the subsequent effect on plaque deposition. Results Tau deletion impaired Aβ clearance via autophagy, but not the proteasome, while introduction of wild type human Tau into Tau−/− mice partially restored autophagic clearance of Aβ1-42, suggesting that exogenous Tau expression can support autophagic Aβ1-42 clearance. Tau deletion impaired autophagic flux and resulted in Aβ1-42 accumulation in pre-lysosomal autophagic vacuoles, affecting Aβ1-42 deposition into the lysosome. This autophagic defect was associated with decreased intracellular Aβ1-42 and increased plaque load in Tau−/− mice, which displayed less cell death. Nilotinib, an Abl tyrosine kinase inhibitor that promotes autophagic clearance mechanisms, reduced Aβ1-42 only when exogenous human Tau was expressed in Tau−/− mice. Conclusions These studies demonstrate that Tau deletion affects intracellular Aβ1-42 clearance, leading to extracellular plaque. Electronic supplementary material The online version of this article (doi:10.1186/1750-1326-9-46) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | | | | | | | - Charbel Moussa
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, 3970 Reservoir RD, Washington, DC 20057, USA.
| |
Collapse
|
105
|
Targeting autophagy in neurodegenerative diseases. Trends Pharmacol Sci 2014; 35:583-91. [DOI: 10.1016/j.tips.2014.09.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/28/2014] [Accepted: 09/03/2014] [Indexed: 12/14/2022]
|
106
|
Zhao W, Zhang J, Davis EG, Rebeck GW. Aging reduces glial uptake and promotes extracellular accumulation of Aβ from a lentiviral vector. Front Aging Neurosci 2014; 6:210. [PMID: 25177293 PMCID: PMC4133689 DOI: 10.3389/fnagi.2014.00210] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/28/2014] [Indexed: 01/27/2023] Open
Abstract
We used a lentiviral system for expressing secreted human Aβ in the brains of young and old APOE knock-in mice. This system allowed us to examine Aβ metabolism in vivo, and test the effects of both aging and APOE genotype, two of the strongest risk factors for Alzheimer’s disease. We injected the Aβ1-42 lentivirus into the motor cortex of young (2 month old) and old (20–22 month old) APOE3 and APOE4 mice. After 2 weeks of lentiviral expression, we analyzed the pattern of Aβ accumulation, glial activation, and phosphor-tau. In young mice, Aβ accumulated mainly within neurons with no evidence of extracellular Aβ. Significantly higher levels of intraneuronal Aβ were observed in APOE4 mice compared to APOE3 mice. In old mice, APOE4 predisposed again to higher levels of Aβ accumulation, but the Aβ was mainly in extracellular spaces. In younger mice, we also observed Aβ in microglia but not astrocytes. The numbers of microglia containing Aβ were significantly higher in APOE3 mice compared to APOE4 mice, and were significantly lower in both genetic backgrounds with aging. The astrocytes in old mice were activated to a greater extent in the brain regions where Aβ was introduced, an effect that was again increased by the presence of APOE4. Finally, phospho-tau accumulated in the region of Aβ expression, with evidence of extracellular phospho-tau increasing with aging. These data suggest that APOE4 predisposes to less microglial clearance of Aβ, leading to more intraneuronal accumulation. In older brains, decreased clearance leads to more extracellular Aβ, and more downstream consequences relating to astrocyte activation and phospho-tau accumulation. We conclude that both aging and APOE genotype affect pathways related to Aβ metabolism by microglia.
Collapse
Affiliation(s)
- Wenjuan Zhao
- School of Pharmacy, Shanghai Jiao Tong University Shanghai, China
| | - Jiguo Zhang
- Department of Pharmacology, School of Pharmacy, Taishan Medical University Taian, China
| | - Elizabeth G Davis
- Department of Neuroscience, Georgetown University Medical Center Washington, DC, USA
| | - G William Rebeck
- Department of Neuroscience, Georgetown University Medical Center Washington, DC, USA
| |
Collapse
|
107
|
Nassif M, Valenzuela V, Rojas-Rivera D, Vidal R, Matus S, Castillo K, Fuentealba Y, Kroemer G, Levine B, Hetz C. Pathogenic role of BECN1/Beclin 1 in the development of amyotrophic lateral sclerosis. Autophagy 2014; 10:1256-71. [PMID: 24905722 DOI: 10.4161/auto.28784] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pharmacological activation of autophagy is becoming an attractive strategy to induce the selective degradation of aggregate-prone proteins. Recent evidence also suggests that autophagy impairment may underlie the pathogenesis of several neurodegenerative diseases. Mutations in the gene encoding SOD1 (superoxide disumutase 1) trigger familial amyotrophic lateral sclerosis (ALS), inducing its misfolding and aggregation and the progressive loss of motoneurons. It is still under debate whether autophagy has a protective or detrimental role in ALS. Here we evaluate the impact of BECN1/Beclin 1, an essential autophagy regulator, in ALS. BECN1 levels were upregulated in both cells and animals expressing mutant SOD1. To evaluate the impact of BECN1 to the pathogenesis of ALS in vivo, we generated mutant SOD1 transgenic mice heterozygous for Becn1. We observed an unexpected increase in life span of mutant SOD1 transgenic mice haploinsufficient for Becn1 compared with littermate control animals. These effects were accompanied by enhanced accumulation of SQSTM1/p62 and reduced levels of LC3-II, and an altered equilibrium between monomeric and oligomeric mutant SOD1 species in the spinal cord. At the molecular level, we detected an abnormal interaction of mutant SOD1 with the BECN1-BCL2L1 complex that may impact autophagy stimulation. Our data support a dual role of BECN1 in ALS and depict a complex scenario in terms of predicting the effects of manipulating autophagy in a disease context.
Collapse
Affiliation(s)
- Melissa Nassif
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Vicente Valenzuela
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Diego Rojas-Rivera
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - René Vidal
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Neurounion Biomedical Foundation; Santiago, Chile
| | - Soledad Matus
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Neurounion Biomedical Foundation; Santiago, Chile
| | - Karen Castillo
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Yerko Fuentealba
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile
| | - Guido Kroemer
- INSERM U848; Villejuif, France; Metabolomics and Cell Biology Platforms; Institut Gustave Roussy; Villejuif, France; Equipe 11 labellisée par la Ligue contre le Cancer; Centre de Recherche des Cordeliers; Paris, France; Pôle de Biologie; Hôpital Européen Georges Pompidou; Paris, France; Université Paris Descartes; Sorbonne Paris Cité; Paris, France
| | - Beth Levine
- Department of Internal Medicine and Howard Hughes Medical Institute; UT Southwestern Medical Center; Dallas, TX USA
| | - Claudio Hetz
- Biomedical Neuroscience Institute; Faculty of Medicine; University of Chile; Santiago, Chile; Center for Molecular Studies of the Cell (CEMC); Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Neurounion Biomedical Foundation; Santiago, Chile; Department of Immunology and Infectious Diseases; Harvard School of Public Health; Boston, MA USA
| |
Collapse
|
108
|
Wenqiang C, Lonskaya I, Hebron ML, Ibrahim Z, Olszewski RT, Neale JH, Moussa CEH. Parkin-mediated reduction of nuclear and soluble TDP-43 reverses behavioral decline in symptomatic mice. Hum Mol Genet 2014; 23:4960-9. [PMID: 24847002 DOI: 10.1093/hmg/ddu211] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The transactivation DNA-binding protein (TDP)-43 binds to thousands of mRNAs, but the functional outcomes of this binding remain largely unknown. TDP-43 binds to Park2 mRNA, which expresses the E3 ubiquitin ligase parkin. We previously demonstrated that parkin ubiquitinates TDP-43 and facilitates its translocation from the nucleus to the cytoplasm. Here we used brain penetrant tyrosine kinase inhibitors (TKIs), including nilotinib and bosutinib and showed that they reduce the level of nuclear TDP-43, abrogate its effects on neuronal loss, and reverse cognitive and motor decline. Nilotinib decreased soluble and insoluble TDP-43, while bosutinib did not affect the insoluble level. Parkin knockout mice exhibited high levels of endogenous TDP-43, while nilotinib and bosutinib did not alter TDP-43, underscoring an indispensable role for parkin in TDP-43 sub-cellular localization. These data demonstrate a novel functional relationship between parkin and TDP-43 and provide evidence that TKIs are potential therapeutic candidates for TDP-43 pathologies.
Collapse
Affiliation(s)
- Chen Wenqiang
- Department of Traditional Chinese Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China Department of Neuroscience
| | - Irina Lonskaya
- Department of Traditional Chinese Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Michaeline L Hebron
- Department of Traditional Chinese Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Zainab Ibrahim
- School of Nursing and Health Sciences, Georgetown University Medical Center, Washington, DC 20007, USA
| | | | | | - Charbel E-H Moussa
- Department of Traditional Chinese Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| |
Collapse
|
109
|
Hebron ML, Lonskaya I, Olopade P, Selby ST, Pagan F, Moussa CEH. Tyrosine Kinase Inhibition Regulates Early Systemic Immune Changes and Modulates the Neuroimmune Response in α-Synucleinopathy. ACTA ACUST UNITED AC 2014; 5:259. [PMID: 25635231 PMCID: PMC4308054 DOI: 10.4172/2155-9899.1000259] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Objectives Neuro-inflammation is common in α-Synucleinopathies and Tauopathies; and evidence suggests a link between the tyrosine kinase Abl and neurodegeneration. Abl upregulates α-Synuclein and promotes Tau hyper-phosphorylation (p-Tau), while Abl inhibitors facilitate autophagic clearance. Methods A model of α-Synucleinopathy harboring human mutant A53T α-Synuclein and exhibits concomitant increase in murine p-Tau was used to determine the immunological response to Abl inhibition. Results Age-dependent alterations of brain immunity, including loss of IL-10 and decreased levels of IL-2 and IL-3 were observed in old A53T mice. Brain CCL2 and CCL5 were decreased, but CX3CL1 remained constantly elevated. Young A53T mice exhibited differential systemic and central immune profiles in parallel with increased blood markers of adaptive immunity, suggesting an early systemic immune response. Tyrosine kinase inhibitors (TKIs), including nilotinib and bosutinib reduced brain and peripheral α-Synuclein and p-Tau and modulated blood immunological responses. TKIs did not affect brain IL-10, but they changed the levels of all measured blood immune markers, except CX3CL1. TKIs altered microglia morphology and reduced the number of astrocyte and dendritic cells, suggesting beneficial regulation of microglia. Conclusions These data indicate that tyrosine kinase inhibition affects neuro-inflammation via early changes of the peripheral immune profile, leading to modulation of the neuro-immune response to α-Synuclein and p-Tau.
Collapse
Affiliation(s)
- Michaeline L Hebron
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington D.C., 20007, USA
| | - Irina Lonskaya
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington D.C., 20007, USA
| | - Paul Olopade
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington D.C., 20007, USA
| | - Sandra T Selby
- Department of Oncology, Lombardi Cancer Center, Georgetown University Medical Center, Washington D.C., 20007, USA
| | - Fernando Pagan
- Neurorestoration Group, Movement Disorders Program, National Parkinson Foundation Center of Excellence, Georgetown University Hospital, Washington D.C., 20007, USA ; Deparment of Neurology, Georgetown University Hospital, Washington D.C., 20007, USA
| | - Charbel E-H Moussa
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington D.C., 20007, USA ; Neurorestoration Group, Movement Disorders Program, National Parkinson Foundation Center of Excellence, Georgetown University Hospital, Washington D.C., 20007, USA
| |
Collapse
|
110
|
Cacabelos R, Cacabelos P, Torrellas C, Tellado I, Carril JC. Pharmacogenomics of Alzheimer's disease: novel therapeutic strategies for drug development. Methods Mol Biol 2014; 1175:323-556. [PMID: 25150875 DOI: 10.1007/978-1-4939-0956-8_13] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is a major problem of health and disability, with a relevant economic impact on our society. Despite important advances in pathogenesis, diagnosis, and treatment, its primary causes still remain elusive, accurate biomarkers are not well characterized, and the available pharmacological treatments are not cost-effective. As a complex disorder, AD is a polygenic and multifactorial clinical entity in which hundreds of defective genes distributed across the human genome may contribute to its pathogenesis. Diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena, together with structural and functional genomic dysfunctions, lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death, the major neuropathological hallmarks of AD. Future perspectives for the global management of AD predict that genomics and proteomics may help in the search for reliable biomarkers. In practical terms, the therapeutic response to conventional drugs (cholinesterase inhibitors, multifactorial strategies) is genotype-specific. Genomic factors potentially involved in AD pharmacogenomics include at least five categories of gene clusters: (1) genes associated with disease pathogenesis; (2) genes associated with the mechanism of action of drugs; (3) genes associated with drug metabolism (phase I and II reactions); (4) genes associated with drug transporters; and (5) pleiotropic genes involved in multifaceted cascades and metabolic reactions. The implementation of pharmacogenomic strategies will contribute to optimize drug development and therapeutics in AD and related disorders.
Collapse
Affiliation(s)
- Ramón Cacabelos
- Chair of Genomic Medicine, Camilo José Cela University, 28692, Villanueva de la Cañada, Madrid, Spain,
| | | | | | | | | |
Collapse
|
111
|
Lonskaya I, Desforges NM, Hebron ML, Moussa CEH. Ubiquitination increases parkin activity to promote autophagic α-synuclein clearance. PLoS One 2013; 8:e83914. [PMID: 24386307 PMCID: PMC3873413 DOI: 10.1371/journal.pone.0083914] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/11/2013] [Indexed: 12/13/2022] Open
Abstract
Parkinson’s disease (PD) is a movement disorder associated with genetic and age related causes. Although autosomal recessive early onset PD linked to parkin mutations does not exhibit α-Synuclein accumulation, while autosomal dominant and sporadic PD manifest with α-Synuclein inclusions, loss of dopaminergic substantia nigra neurons is a common denominator in PD. Here we show that decreased parkin ubiquitination and loss of parkin stability impair interaction with Beclin-1 and alter α-Synuclein degradation, leading to death of dopaminergic neurons. Tyrosine kinase inhibition increases parkin ubiquitination and interaction with Beclin-1, promoting autophagic α-Synuclein clearance and nigral neuron survival. However, loss of parkin via deletion increases α-Synuclein in the blood compared to the brain, suggesting that functional parkin prevents α-Synuclein release into the blood. These studies demonstrate that parkin ubiquitination affects its protein stability and E3 ligase activity, possibly leading to α-Synuclein sequestration and subsequent clearance.
Collapse
Affiliation(s)
- Irina Lonskaya
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington, DC, United States of America
| | - Nicole M. Desforges
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington, DC, United States of America
| | - Michaeline L. Hebron
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington, DC, United States of America
| | - Charbel E-H. Moussa
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, Washington, DC, United States of America
- * E-mail:
| |
Collapse
|
112
|
Lonskaya I, Hebron ML, Desforges NM, Schachter JB, Moussa CEH. Nilotinib-induced autophagic changes increase endogenous parkin level and ubiquitination, leading to amyloid clearance. J Mol Med (Berl) 2013; 92:373-86. [PMID: 24337465 DOI: 10.1007/s00109-013-1112-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/15/2013] [Accepted: 11/28/2013] [Indexed: 12/13/2022]
Abstract
UNLABELLED Alzheimer's disease (AD) is a neurodegenerative disorder associated with amyloid accumulation and autophagic changes. Parkin is an E3 ubiquitin ligase involved in proteasomal and autophagic clearance. We previously demonstrated decreased parkin solubility and interaction with the key autophagy enzyme beclin-1 in AD, but tyrosine kinase inhibition restored parkin-beclin-1 interaction. In the current studies, we determined the mechanisms of nilotinib-induced parkin-beclin-1 interaction, which leads to amyloid clearance. Nilotinib increased endogenous parkin levels and ubiquitination, which may enhance parkin recycling via the proteasome, leading to increased activity and interaction with beclin-1. Parkin solubility was decreased and autophagy was altered in amyloid expressing mice, suggesting that amyloid stress affects parkin stability, leading to failure of protein clearance via the lysosome. Isolation of autophagic vacuoles revealed amyloid and parkin accumulation in autophagic compartments but nilotinib decreased insoluble parkin levels and facilitated amyloid deposition into lysosomes in wild type, but not parkin(-/-) mice, further underscoring an essential role for endogenous parkin in amyloid clearance. These results suggest that nilotinib boosts the autophagic machinery, leading to increased level of endogenous parkin that undergoes ubiquitination and interacts with beclin-1 to facilitate amyloid clearance. These data suggest that nilotinib-mediated autophagic changes may trigger parkin response via increased protein levels, providing a therapeutic strategy to reduce Aβ and Tau in AD. KEY MESSAGE Parkin solubility (stability) is decreased in AD and APP transgenic mice. Nilotinib-induced autophagic changes increase endogenous parkin level. Increased parkin level leads to ubiquitination and proteasomal recycling. Re-cycling decreases insoluble parkin and increases parkin-beclin-1 interaction. Beclin-1-parkin interaction enhances amyloid clearance.
Collapse
Affiliation(s)
- Irina Lonskaya
- Department of Neuroscience, Laboratory for Dementia and Parkinsonism, Georgetown University Medical Center, 3970 Reservoir Rd, NW, TRB, Room WP26B, Washington, DC, 20057, USA
| | | | | | | | | |
Collapse
|