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Dominguez-Meijide A, Vasili E, König A, Cima-Omori MS, Ibáñez de Opakua A, Leonov A, Ryazanov S, Zweckstetter M, Griesinger C, Outeiro TF. Effects of pharmacological modulators of α-synuclein and tau aggregation and internalization. Sci Rep 2020; 10:12827. [PMID: 32732936 PMCID: PMC7393090 DOI: 10.1038/s41598-020-69744-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) and Alzheimer's disease (AD) are common neurodegenerative disorders of the elderly and, therefore, affect a growing number of patients worldwide. Both diseases share, as a common hallmark, the accumulation of characteristic protein aggregates, known as Lewy bodies (LB) in PD, and neurofibrillary tangles in AD. LBs are primarily composed of misfolded α-synuclein (aSyn), and neurofibrillary tangles are primarily composed of tau protein. Importantly, upon pathological evaluation, most AD and PD/Lewy body dementia cases exhibit mixed pathology, with the co-occurrence of both LB and neurofibrillary tangles, among other protein inclusions. Recent studies suggest that both aSyn and tau pathology can spread and propagate through neuronal connections. Therefore, it is important to investigate the mechanisms underlying aggregation and propagation of these proteins for the development of novel therapeutic strategies. Here, we assessed the effects of different pharmacological interventions on the aggregation and internalization of tau and aSyn. We found that anle138b and fulvic acid decrease aSyn and tau aggregation, that epigallocatechin gallate decreases aSyn aggregation, and that dynasore reduces tau internalization. Establishing the effects of small molecules with different chemical properties on the aggregation and spreading of aSyn and tau will be important for the development of future therapeutic interventions.
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Affiliation(s)
- Antonio Dominguez-Meijide
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, 37073, Göttingen, Germany.,Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, IDIS, University of Santiago de Compostela, Santiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Eftychia Vasili
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, 37073, Göttingen, Germany
| | - Annekatrin König
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, 37073, Göttingen, Germany
| | - Maria-Sol Cima-Omori
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Alain Ibáñez de Opakua
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Andrei Leonov
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Sergey Ryazanov
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.,Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.,Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Christian Griesinger
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, 37073, Göttingen, Germany. .,Max Planck Institute for Experimental Medicine, Göttingen, Germany. .,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK.
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Fan F, Ji C, Wu Y, Ferguson SM, Tamarina N, Philipson LH, Lou X. Dynamin 2 regulates biphasic insulin secretion and plasma glucose homeostasis. J Clin Invest 2015; 125:4026-41. [PMID: 26413867 DOI: 10.1172/jci80652] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 08/20/2015] [Indexed: 12/18/2022] Open
Abstract
Alterations in insulin granule exocytosis and endocytosis are paramount to pancreatic β cell dysfunction in diabetes mellitus. Here, using temporally controlled gene ablation specifically in β cells in mice, we identified an essential role of dynamin 2 GTPase in preserving normal biphasic insulin secretion and blood glucose homeostasis. Dynamin 2 deletion in β cells caused glucose intolerance and substantial reduction of the second phase of glucose-stimulated insulin secretion (GSIS); however, mutant β cells still maintained abundant insulin granules, with no signs of cell surface expansion. Compared with control β cells, real-time capacitance measurements demonstrated that exocytosis-endocytosis coupling was less efficient but not abolished; clathrin-mediated endocytosis (CME) was severely impaired at the step of membrane fission, which resulted in accumulation of clathrin-coated endocytic intermediates on the plasma membrane. Moreover, dynamin 2 ablation in β cells led to striking reorganization and enhancement of actin filaments, and insulin granule recruitment and mobilization were impaired at the later stage of GSIS. Together, our results demonstrate that dynamin 2 regulates insulin secretory capacity and dynamics in vivo through a mechanism depending on CME and F-actin remodeling. Moreover, this study indicates a potential pathophysiological link between endocytosis and diabetes mellitus.
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Fà M, Staniszewski A, Saeed F, Francis YI, Arancio O. Dynamin 1 is required for memory formation. PLoS One 2014; 9:e91954. [PMID: 24643165 PMCID: PMC3958425 DOI: 10.1371/journal.pone.0091954] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/16/2014] [Indexed: 02/07/2023] Open
Abstract
Dynamin 1–3 isoforms are known to be involved in endocytotic processes occurring during synaptic transmission. No data has directly linked dynamins yet with normal animal behavior. Here we show that dynamin pharmacologic inhibition markedly impairs hippocampal-dependent associative memory. Memory loss was associated with changes in synaptic function occurring during repetitive stimulation that is thought to be linked with memory induction. Synaptic fatigue was accentuated by dynamin inhibition. Moreover, dynamin inhibition markedly reduced long-term potentiation, post-tetanic potentiation, and neurotransmitter released during repetitive stimulation. Most importantly, the effect of dynamin inhibition onto memory and synaptic plasticity was due to a specific involvement of the dynamin 1 isoform, as demonstrated through a genetic approach with siRNA against this isoform to temporally block it. Taken together, these findings identify dynamin 1 as a key protein for modulation of memory and release evoked by repetitive activity.
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Affiliation(s)
- Mauro Fà
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Agnieszka Staniszewski
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Faisal Saeed
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Yitshak I. Francis
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
- * E-mail:
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Straub SG, Sharp GWG. Evolving insights regarding mechanisms for the inhibition of insulin release by norepinephrine and heterotrimeric G proteins. Am J Physiol Cell Physiol 2012; 302:C1687-98. [PMID: 22492651 DOI: 10.1152/ajpcell.00282.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Norepinephrine has for many years been known to have three major effects on the pancreatic β-cell which lead to the inhibition of insulin release. These are activation of K(+) channels to hyperpolarize the cell and prevent the gating of voltage-dependent Ca(2+) channels that increase intracellular Ca(2+) concentration ([Ca(2+)](i)) and trigger release; inhibition of adenylyl cyclases, thus preventing the augmentation of stimulated insulin release by cyclic AMP; and a "distal" effect that occurs downstream of increased [Ca(2+)](i) to inhibit exocytosis. All three are mediated by the pertussis toxin (PTX)-sensitive heterotrimeric Gi and Go proteins. The distal inhibitory effect on exocytosis is now known to be due to the binding of G protein βγ subunits to the synaptosomal-associated protein of 25 kDa (SNAP-25) on the soluble NSF attachment protein receptor (SNARE) complex. Recent studies have uncovered two more actions of norepinephrine on the β-cell: 1) retardation of the refilling of the readily releasable granule pool after it has been discharged, an action that is mediated by Gαi(1) and/or Gαi(2); and 2) inhibition of endocytosis that is mediated by Gz. Of importance also are new findings that Gαo regulates the number of docked granules in the β-cell, and that Gαo(2) maintains a tonic inhibitory influence on secretion. The latter provides another explanation as to why PTX, which blocks the effect of Gαo(2), was initially called "islet activating protein." Finally, there is clear evidence that overexpression of α(2A)-adrenergic receptors in β-cells can cause type 2 diabetes.
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Affiliation(s)
- Susanne G Straub
- Department of Molecular Medicine, Cornell University, Ithaca, New York 14853-6401, USA
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Delayed endosome-dependent CamKII and p38 kinase signaling in cardiomyocytes destabilizes Kv4.3 mRNA. J Mol Cell Cardiol 2012; 52:971-7. [PMID: 22266351 DOI: 10.1016/j.yjmcc.2012.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 12/20/2011] [Accepted: 01/03/2012] [Indexed: 12/22/2022]
Abstract
The Kv4.3 transient outward current (I(to)) channel, which produces early repolarization in human cardiomyocytes, is downregulated with cardiac pathology. This is evident in cultured neonatal rat cardiomyocytes in which Angiotensin II (Ang II) acts via p38 mitogen-activated protein kinase (p38K) to increase apoptosis and induce Kv4.3 mRNA destabilization to downregulate the channel protein. However, it is not understood how p38K activation, which is activated transiently for minutes, induces downstream effects hours later. Here we show that there is a second phase of p38K activation. Inhibiting this delayed p38K activation eliminated Kv4.3 mRNA destabilization. Furthermore, inhibiting endosome generation left the transient activation of p38K intact, but blocked delayed p38K activation and the Kv4.3 effect. CamKII was also found to be required for delayed p38K activation and Kv4.3 mRNA destabilization. Finally, CamKII methionine oxidation and activation are biphasic, with the delayed phase requiring endosomes. Hence, in addition to participating in channel traffic, cardiomyocyte endosomes control channel mRNA expression by mediating delayed oxidative CamKII-p38K signaling.
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Liang K, Du W, Zhu W, Liu S, Cui Y, Sun H, Luo B, Xue Y, Yang L, Chen L, Li F. Contribution of different mechanisms to pancreatic beta-cell hyper-secretion in non-obese diabetic (NOD) mice during pre-diabetes. J Biol Chem 2011; 286:39537-45. [PMID: 21914804 DOI: 10.1074/jbc.m111.295931] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The development of insulin-dependent diabetes mellitus (IDDM) results from the selective destruction of pancreatic beta-cells. Both humans and spontaneous models of IDDM, such as NOD mice, have an extended pre-diabetic stage. Dynamic changes in beta-cell mass and function during pre-diabetes, such as insulin hyper-secretion, remain largely unknown. In this paper, we evaluated pre-diabetic female NOD mice at different ages (6, 10, and 14 weeks old) to illustrate alterations in beta-cell mass and function as disease progressed. We found an increase in beta-cell mass in 6-week-old NOD mice that may account for improved glucose tolerance in these mice. As NOD mice aged, beta-cell mass progressively reduced with increasing insulitis. In parallel, secretory ability of individual beta-cells was enhanced due to an increase in the size of slowly releasable pool (SRP) of vesicles. Moreover, expression of both SERCA2 and SERCA3 genes were progressively down-regulated, which facilitated depolarization-evoked secretion by prolonging Ca(2+) elevation upon glucose stimulation. In summary, we propose that different mechanisms contribute to the insulin hyper-secretion at different ages of pre-diabetic NOD mice, which may provide some new ideas concerning the progression and management of type I diabetes.
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Affiliation(s)
- Kuo Liang
- Department of General Surgery, XuanWu Hospital, Capital Medical University, Beijing, 100053, PR China
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