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Skeens A, Markle JM, Petipas G, Frey SL, Legleiter J. Divalent cations promote huntingtin fibril formation on endoplasmic reticulum derived and model membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184339. [PMID: 38763270 DOI: 10.1016/j.bbamem.2024.184339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 04/24/2024] [Accepted: 05/12/2024] [Indexed: 05/21/2024]
Abstract
Huntington's Disease (HD) is caused by an abnormal expansion of the polyglutamine (polyQ) domain within the first exon of the huntingtin protein (htt). This expansion promotes disease-related htt aggregation into amyloid fibrils and the formation of proteinaceous inclusion bodies within neurons. Fibril formation is a complex heterogenous process involving an array of aggregate species such as oligomers, protofibrils, and fibrils. In HD, structural abnormalities of membranes of several organelles develop. In particular, the accumulation of htt fibrils near the endoplasmic reticulum (ER) impinges upon the membrane, resulting in ER damage, altered dynamics, and leakage of Ca2+. Here, the aggregation of htt at a bilayer interface assembled from ER-derived liposomes was investigated, and fibril formation directly on these membranes was enhanced. Based on these observations, simplified model systems were used to investigate mechanisms associated with htt aggregation on ER membranes. As the ER-derived liposome fractions contained residual Ca2+, the role of divalent cations was also investigated. In the absence of lipids, divalent cations had minimal impact on htt structure and aggregation. However, the presence of Ca2+ or Mg2+ played a key role in promoting fibril formation on lipid membranes despite reduced htt insertion into and association with lipid interfaces, suggesting that the ability of divalent cations to promote fibril formation on membranes is mediated by induced changes to the lipid membrane physicochemical properties. With enhanced concentrations of intracellular calcium being a hallmark of HD, the ability of divalent cations to influence htt aggregation at lipid membranes may play a role in aggregation events that lead to organelle abnormalities associated with disease.
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Affiliation(s)
- Adam Skeens
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Jordyn M Markle
- The Department of Chemistry, Gettysburg College, 300 N. Washington Street, Gettysburg, PA 17325, USA
| | - Gabriella Petipas
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Shelli L Frey
- The Department of Chemistry, Gettysburg College, 300 N. Washington Street, Gettysburg, PA 17325, USA.
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA; Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA.
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2
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Chen Y, Xu R, Liu Q, Zeng Y, Chen W, Liu Y, Cao Y, Liu G, Chen Y. Rosmarinic acid ameliorated oxidative stress, neuronal injuries, and mitochondrial dysfunctions mediated by polyglutamine and ɑ-synuclein in Caenorhabditis elegans models. Mol Neurobiol 2024:10.1007/s12035-024-04206-4. [PMID: 38703342 DOI: 10.1007/s12035-024-04206-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024]
Abstract
Numerous natural antioxidants have been developed into agents for neurodegenerative diseases (NDs) treatment. Rosmarinic acid (RA), an excellent antioxidant, exhibits neuroprotective activity, but its anti-NDs efficacy remains puzzling. Here, Caenorhabditis elegans models were employed to systematically reveal RA-mediated mechanisms in delaying NDs from diverse facets, including oxidative stress, the homeostasis of neural and protein, and mitochondrial disorders. Firstly, RA significantly inhibited reactive oxygen species accumulation, reduced peroxide malonaldehyde production, and strengthened the antioxidant defense system via increasing superoxide dismutase activity. Besides, RA reduced neuronal loss and ameliorated polyglutamine and ɑ-synuclein-mediated dyskinesia in NDs models. Further, in combination with the data and molecular docking results, RA may bind specifically to Huntington protein and ɑ-synuclein to prevent toxic protein aggregation and thus enhance proteostasis. Finally, RA ameliorated mitochondrial dysfunction including increasing adenosine triphosphate and mitochondrial membrane potential levels and rescuing mitochondrial membrane proteins' expressions and mitochondrial structural abnormalities via regulating mitochondrial dynamics genes and improving the mitochondrial kinetic homeostasis. Thus, this study systematically revealed the RA-mediated neuroprotective mechanism and promoted RA as a promising nutritional intervention strategy to prevent NDs.
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Affiliation(s)
- Yun Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Ruina Xu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Qiaoxing Liu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Yanting Zeng
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Weitian Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Yongfa Liu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Yong Cao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China
| | - Guo Liu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China.
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, Guangdong, China.
| | - Yunjiao Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, 510640, Guangdong, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510640, Guangdong, China.
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3
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Skeens A, Siriwardhana C, Massinople SE, Wunder MM, Ellis ZL, Keith KM, Girman T, Frey SL, Legleiter J. The polyglutamine domain is the primary driver of seeding in huntingtin aggregation. PLoS One 2024; 19:e0298323. [PMID: 38483973 PMCID: PMC10939245 DOI: 10.1371/journal.pone.0298323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 01/22/2024] [Indexed: 03/17/2024] Open
Abstract
Huntington's Disease (HD) is a fatal, neurodegenerative disease caused by aggregation of the huntingtin protein (htt) with an expanded polyglutamine (polyQ) domain into amyloid fibrils. Htt aggregation is modified by flanking sequences surrounding the polyQ domain as well as the binding of htt to lipid membranes. Upon fibrillization, htt fibrils are able to template the aggregation of monomers into fibrils in a phenomenon known as seeding, and this process appears to play a critical role in cell-to-cell spread of HD. Here, exposure of C. elegans expressing a nonpathogenic N-terminal htt fragment (15-repeat glutamine residues) to preformed htt-exon1 fibrils induced inclusion formation and resulted in decreased viability in a dose dependent manner, demonstrating that seeding can induce toxic aggregation of nonpathogenic forms of htt. To better understand this seeding process, the impact of flanking sequences adjacent to the polyQ stretch, polyQ length, and the presence of model lipid membranes on htt seeding was investigated. Htt seeding readily occurred across polyQ lengths and was independent of flanking sequence, suggesting that the structured polyQ domain within fibrils is the key contributor to the seeding phenomenon. However, the addition of lipid vesicles modified seeding efficiency in a manner suggesting that seeding primarily occurs in bulk solution and not at the membrane interface. In addition, fibrils formed in the presence of lipid membranes displayed similar seeding efficiencies. Collectively, this suggests that the polyQ domain that forms the amyloid fibril core is the main driver of seeding in htt aggregation.
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Affiliation(s)
- Adam Skeens
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Chathuranga Siriwardhana
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Sophia E. Massinople
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Michelle M. Wunder
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Zachary L. Ellis
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Kaitlyn M. Keith
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Tyler Girman
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Shelli L. Frey
- The Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania, United States of America
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
- Rockefeller Neurosciences Institutes, West Virginia University, Morgantown, West Virginia, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia, United States of America
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4
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Gamage YI, Pan J. Elucidating the Influence of Lipid Composition on Bilayer Perturbations Induced by the N-terminal Region of the Huntingtin Protein. BIOPHYSICA 2023; 3:582-597. [PMID: 38737720 PMCID: PMC11087071 DOI: 10.3390/biophysica3040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Understanding the membrane interactions of the N-terminal 17 residues of the huntingtin protein (HttN) is essential for unraveling its role in cellular processes and its impact on huntingtin misfolding. In this study, we used atomic force microscopy (AFM) to examine the effects of lipid specificity in mediating bilayer perturbations induced by HttN. Across various lipid environments, the peptide consistently induced bilayer disruptions in the form of holes. Notably, our results unveiled that cholesterol enhanced bilayer perturbation induced by HttN, while phosphatidylethanolamine (PE) lipids suppressed hole formation. Furthermore, anionic phosphatidylglycerol (PG) and cardiolipin lipids, along with cholesterol at high concentrations, promoted the formation of double-bilayer patches. This unique structure suggests that the synergy among HttN, anionic lipids, and cholesterol can enhance bilayer fusion, potentially by facilitating lipid intermixing between adjacent bilayers. Additionally, our AFM-based force spectroscopy revealed that HttN enhanced the mechanical stability of lipid bilayers, as evidenced by an elevated bilayer puncture force. These findings illuminate the complex interplay between HttN and lipid membranes and provide useful insights into the role of lipid composition in modulating membrane interactions with the huntingtin protein.
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Affiliation(s)
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620
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5
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Burtscher J, Pepe G, Maharjan N, Riguet N, Di Pardo A, Maglione V, Millet GP. Sphingolipids and impaired hypoxic stress responses in Huntington disease. Prog Lipid Res 2023; 90:101224. [PMID: 36898481 DOI: 10.1016/j.plipres.2023.101224] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/20/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Huntington disease (HD) is a debilitating, currently incurable disease. Protein aggregation and metabolic deficits are pathological hallmarks but their link to neurodegeneration and symptoms remains debated. Here, we summarize alterations in the levels of different sphingolipids in an attempt to characterize sphingolipid patterns specific to HD, an additional molecular hallmark of the disease. Based on the crucial role of sphingolipids in maintaining cellular homeostasis, the dynamic regulation of sphingolipids upon insults and their involvement in cellular stress responses, we hypothesize that maladaptations or blunted adaptations, especially following cellular stress due to reduced oxygen supply (hypoxia) contribute to the development of pathology in HD. We review how sphingolipids shape cellular energy metabolism and control proteostasis and suggest how these functions may fail in HD and in combination with additional insults. Finally, we evaluate the potential of improving cellular resilience in HD by conditioning approaches (improving the efficiency of cellular stress responses) and the role of sphingolipids therein. Sphingolipid metabolism is crucial for cellular homeostasis and for adaptations following cellular stress, including hypoxia. Inadequate cellular management of hypoxic stress likely contributes to HD progression, and sphingolipids are potential mediators. Targeting sphingolipids and the hypoxic stress response are novel treatment strategies for HD.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, 1015 Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, 1005 Lausanne, Switzerland.
| | - Giuseppe Pepe
- IRCCS Neuromed, Via Dell'Elettronica, 86077 Pozzilli, Italy
| | - Niran Maharjan
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, 3010 Bern, Switzerland; Department for Biomedical Research (DBMR), University of Bern, 3010 Bern, Switzerland
| | | | - Alba Di Pardo
- IRCCS Neuromed, Via Dell'Elettronica, 86077 Pozzilli, Italy
| | | | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, 1015 Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, 1005 Lausanne, Switzerland
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6
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Adegbuyiro A, Stonebraker AR, Sedighi F, Fan CK, Hodges B, Li P, Valentine SJ, Legleiter J. Oxidation Promotes Distinct Huntingtin Aggregates in the Presence and Absence of Membranes. Biochemistry 2022; 61:1517-1530. [PMID: 35759798 DOI: 10.1021/acs.biochem.2c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expansion of a polyglutamine (polyQ) domain within the first exon of the huntingtin (htt) protein is the underlying cause of Huntington's disease, a genetic neurodegenerative disorder. PolyQ expansion triggers htt aggregation into oligomers, fibrils, and inclusions. The 17 N-terminal amino acids (Nt17) of htt-exon1, which directly precede the polyQ domain enhances polyQ fibrillization and functions as a lipid-binding domain. A variety of post-translational modifications occur within Nt17, including oxidation of two methionine residues. Here, the impact of oxidation within Nt17 on htt aggregation both in the presence and absence of lipid membranes was investigated. Treatment with hydrogen peroxide (H2O2) reduced fibril formation in a dose-dependent manner, resulting in shorter fibrils and an increased oligomer population. With excessive H2O2 treatments, fibrils developed a unique morphological feature around their periphery. In the presence of total brain lipid vesicles, H2O2 impacted fibrillization in a similar manner. That is, oligomerization was promoted at the expense of fibril elongation. The interaction of unoxidized and oxidized htt with supported lipid bilayers was directly observed using in situ atomic force microscopy. Without oxidation, granular htt aggregates developed on the bilayer surface. However, in the presence of H2O2, distinct plateau-like regions initially developed on the bilayer surface that gave way to rougher patches containing granular aggregates. Collectively, these observations suggest that oxidation of methionine residues within Nt17 plays a crucial role in both the aggregation of htt and its ability to interact with lipid surfaces.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Caleb K Fan
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Breanna Hodges
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Peng Li
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States
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7
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Phospholipid Profiles Are Selectively Altered in the Putamen and White Frontal Cortex of Huntington's Disease. Nutrients 2022; 14:nu14102086. [PMID: 35631226 PMCID: PMC9143248 DOI: 10.3390/nu14102086] [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] [Received: 04/26/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 11/17/2022] Open
Abstract
Huntington’s disease (HD) is a genetic, neurodegenerative illness that onsets in late adulthood as a series of progressive and terminal cognitive, motor, and psychiatric deficits. The disease is caused by a polyQ mutation in the Huntingtin gene (HTT), producing a polyglutamine expansion in the Huntingtin protein (HTT). HTT interacts with phospholipids in vitro; however, its interactions are changed when the protein is mutated in HD. Emerging evidence suggests that the susceptibility of brain regions to pathological stimuli is influenced by lipid composition. This study aimed to identify where and how phospholipids are changed in human HD brain tissue. Phospholipids were extracted using a modified MTBE method from the post-mortem brain of 13 advanced-stage HD patients and 13 age- and sex-matched controls. Targeted precursor ion scanning mass spectrometry was used to detect phospholipid species. In the white cortex of HD patients, there was a significantly lower abundance of phosphatidylcholine (PC) and phosphatidylserine (PS), but no difference in phosphatidylethanolamine (PE). In HD putamen, ester-linked 22:6 was lower in all phospholipid classes promoting a decrease in the relative abundance of ester polyunsaturated fatty acids in PE. No differences in phospholipid composition were identified in the caudate, grey cortex or cerebellum. Ether-linked PE fatty acids appear protected in the HD brain, as no changes were identified. The nature of phospholipid alterations in the HD brain is dependent on the lipid (subclass, species, and bond type) and the location.
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8
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Roy M, Nath AK, Pal I, Dey SG. Second Sphere Interactions in Amyloidogenic Diseases. Chem Rev 2022; 122:12132-12206. [PMID: 35471949 DOI: 10.1021/acs.chemrev.1c00941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.
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Affiliation(s)
- Madhuparna Roy
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arnab Kumar Nath
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Ishita Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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9
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Beasley M, Frazee N, Groover S, Valentine SJ, Mertz B, Legleiter J. Physicochemical Properties Altered by the Tail Group of Lipid Membranes Influence Huntingtin Aggregation and Lipid Binding. J Phys Chem B 2022; 126:3067-3081. [PMID: 35439000 DOI: 10.1021/acs.jpcb.1c10254] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Huntington's disease is a neurodegenerative disorder caused by an expanded polyglutamine (polyQ) domain within the huntingtin protein (htt) that initiates toxic protein aggregation. Htt directly interacts with membranes, influencing aggregation and spurring membrane abnormalities. These interactions are facilitated by the 17 N-terminal residues (Nt17) that form an amphipathic α-helix implicated in both lipid binding and aggregation. Here, the impact of unsaturation in phospholipid tails on htt-lipid interaction and htt aggregation was determined. There was no correlation between the degree of htt-lipid complexation and the degree of htt aggregation in the presence of each lipid system, indicating that lipid systems with different properties uniquely alter the membrane-mediated aggregation mechanisms. Also, the association between Nt17 and membrane surfaces is determined by complementarity between hydrophobic residues and membrane defects and how easily the peptide can partition into the bilayer. Our results provide critical insights into how membrane physical properties influence downstream htt aggregation.
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Affiliation(s)
- Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Nicolas Frazee
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Sharon Groover
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Blake Mertz
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,WVU Cancer Institute, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Blanchette Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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10
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Phillips GR, Saville JT, Hancock SE, Brown SHJ, Jenner AM, McLean C, Fuller M, Newell KA, Mitchell TW. The long and the short of Huntington’s disease: how the sphingolipid profile is shifted in the caudate of advanced clinical cases. Brain Commun 2021; 4:fcab303. [PMID: 35169703 PMCID: PMC8833324 DOI: 10.1093/braincomms/fcab303] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/27/2021] [Accepted: 12/21/2021] [Indexed: 01/01/2023] Open
Abstract
Huntington’s disease is a devastating neurodegenerative disorder that onsets in late adulthood as progressive and terminal cognitive, psychiatric and motor deficits. The disease is genetic, triggered by a CAG repeat (polyQ) expansion mutation in the Huntingtin gene and resultant huntingtin protein. Although the mutant huntingtin protein is ubiquitously expressed, the striatum degenerates early and consistently in the disease. The polyQ mutation at the N-terminus of the huntingtin protein alters its natural interactions with neural phospholipids in vitro, suggesting that the specific lipid composition of brain regions could influence their vulnerability to interference by mutant huntingtin; however, this has not yet been demonstrated in vivo. Sphingolipids are critical cell signalling molecules, second messengers and membrane components. Despite evidence of sphingolipid disturbance in Huntington’s mouse and cell models, there is limited knowledge of how these lipids are affected in human brain tissue. Using post-mortem brain tissue from five brain regions implicated in Huntington’s disease (control n = 13, Huntington’s n = 13), this study aimed to identify where and how sphingolipid species are affected in the brain of clinically advanced Huntington’s cases. Sphingolipids were extracted from the tissue and analysed using targeted mass spectrometry analysis; proteins were analysed by western blot. The caudate, putamen and cerebellum had distinct sphingolipid changes in Huntington’s brain whilst the white and grey frontal cortex were spared. The caudate of Huntington’s patients had a shifted sphingolipid profile, favouring long (C13–C21) over very-long-chain (C22–C26) ceramides, sphingomyelins and lactosylceramides. Ceramide synthase 1, which synthesizes the long-chain sphingolipids, had a reduced expression in Huntington’s caudate, correlating positively with a younger age at death and a longer CAG repeat length of the Huntington’s patients. The expression of ceramide synthase 2, which synthesizes very-long-chain sphingolipids, was not different in Huntington’s brain. However, there was evidence of possible post-translational modifications in the Huntington’s patients only. Post-translational modifications to ceramide synthase 2 may be driving the distinctive sphingolipid profile shifts of the caudate in advanced Huntington’s disease. This shift in the sphingolipid profile is also found in the most severely affected brain regions of several other neurodegenerative conditions and may be an important feature of region-specific cell dysfunction in neurodegenerative disease.
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Affiliation(s)
- Gabrielle R. Phillips
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Jennifer T. Saville
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
| | - Sarah E. Hancock
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Simon H. J. Brown
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Andrew M. Jenner
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Catriona McLean
- Department of Anatomical Pathology, Alfred Health and Florey Neuroscience, Parkville, VIC 3052, Australia
| | - Maria Fuller
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
- Adelaide Medical School, University of Adelaide, Adelaide, SA 5000, Australia
| | - Kelly A. Newell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Todd W. Mitchell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
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11
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The Cytotoxicity and Clearance of Mutant Huntingtin and Other Misfolded Proteins. Cells 2021; 10:cells10112835. [PMID: 34831058 PMCID: PMC8616338 DOI: 10.3390/cells10112835] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 02/07/2023] Open
Abstract
Protein misfolding and aggregation are implicated in many neurodegenerative diseases. One of these diseases is Huntington's, which is caused by increased glutamine-encoding trinucleotide repeats within the Huntingtin gene. Like other misfolded proteins, mutated Huntingtin proteins with polyglutamine expansions are prone to aggregation. Misfolded proteins exist as soluble monomers, small aggregates, or as large insoluble inclusion bodies. Misfolded protein aggregates are believed to be cytotoxic by stressing the protein degradation machinery, disrupting membrane structure, or sequestering other proteins. We recently showed that expression of misfolded proteins lowers cellular free ubiquitin levels, which compromises the protein degradation machinery. Therefore, the efficient degradation of misfolded proteins is critical to preserve cell health. Cells employ two major mechanisms to degrade misfolded proteins. The first is the ubiquitin-proteasome system (UPS), which ubiquitinates and degrades misfolded proteins with the assistance of segregase Cdc48/p97. The UPS pathway is mainly responsible for the clearance of misfolded proteins present as monomers or smaller aggregates. The second pathway is macroautophagy/autophagy, in which protein aggregates or inclusion bodies are recruited into an autophagosome before transport to the vacuole/lysosome for degradation. This review is focused on the current understanding of the cytotoxicity of misfolded proteins as well as their clearance pathways, with a particular emphasis on mutant Huntingtin.
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12
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Vieweg S, Mahul-Mellier AL, Ruggeri FS, Riguet N, DeGuire SM, Chiki A, Cendrowska U, Dietler G, Lashuel HA. The Nt17 Domain and its Helical Conformation Regulate the Aggregation, Cellular Properties and Neurotoxicity of Mutant Huntingtin Exon 1. J Mol Biol 2021; 433:167222. [PMID: 34492254 DOI: 10.1016/j.jmb.2021.167222] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022]
Abstract
Converging evidence points to the N-terminal domain comprising the first 17 amino acids of the Huntingtin protein (Nt17) as a key regulator of its aggregation, cellular properties and toxicity. In this study, we further investigated the interplay between Nt17 and the polyQ domain repeat length in regulating the aggregation and inclusion formation of exon 1 of the Huntingtin protein (Httex1). In addition, we investigated the effect of removing Nt17 or modulating its local structure on the membrane interactions, neuronal uptake, and toxicity of monomeric or fibrillar Httex1. Our results show that the polyQ and Nt17 domains synergistically modulate the aggregation propensity of Httex1 and that the Nt17 domain plays important roles in shaping the surface properties of mutant Httex1 fibrils and regulating their poly-Q-dependent growth, lateral association and neuronal uptake. Removal of Nt17 or disruption of its transient helical conformations slowed the aggregation of monomeric Httex1 in vitro, reduced inclusion formation in cells, enhanced the neuronal uptake and nuclear accumulation of monomeric Httex1 proteins, and was sufficient to prevent cell death induced by Httex1 72Q overexpression. Finally, we demonstrate that the uptake of Httex1 fibrils into primary neurons and the resulting toxicity are strongly influenced by mutations and phosphorylation events that influence the local helical propensity of Nt17. Altogether, our results demonstrate that the Nt17 domain serves as one of the key master regulators of Htt aggregation, internalization, and toxicity and represents an attractive target for inhibiting Htt aggregate formation, inclusion formation, and neuronal toxicity.
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Affiliation(s)
- Sophie Vieweg
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anne-Laure Mahul-Mellier
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Francesco S Ruggeri
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Nathan Riguet
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean M DeGuire
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Urszula Cendrowska
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Giovanni Dietler
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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13
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Adegbuyiro A, Sedighi F, Jain P, Pinti MV, Siriwardhana C, Hollander JM, Legleiter J. Mitochondrial membranes modify mutant huntingtin aggregation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183663. [PMID: 34089719 PMCID: PMC8328955 DOI: 10.1016/j.bbamem.2021.183663] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/17/2021] [Accepted: 05/28/2021] [Indexed: 02/08/2023]
Abstract
Huntington's disease (HD) is a neurodegenerative disease caused by the expansion of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ tracts are prone to aggregate into oligomers and insoluble fibrils. Mutant htt (mhtt) localizes to variety of organelles, including mitochondria. Specifically, mitochondrial defects, morphological alteration, and dysfunction are observed in HD. Mitochondrial lipids, cardiolipin (CL) in particular, are essential in mitochondria function and have the potential to directly interact with htt, altering its aggregation. Here, the impact of mitochondrial membranes on htt aggregation was investigated using a combination of mitochondrial membrane mimics and tissue-derived mitochondrial-enriched fractions. The impact of exposure of outer and inner mitochondrial membrane mimics (OMM and IMM respectively) to mhtt was explored. OMM and IMM reduced mhtt fibrillization, with IMM having a larger effect. The role of CL in mhtt aggregation was investigated using a simple PC system with varying molar ratios of CL. Lower molar ratios of CL (<5%) promoted fibrillization; however, increased CL content retarded fibrillization. As revealed by in situ AFM, mhtt aggregation and associated membrane morphological changes at the surface of OMM mimics was markedly different compared to IMM mimics. While globular deposits of mhtt with few fibrillar aggregates were observed on OMM, plateau-like domains were observed on IMM. A similar impact on htt aggregation was observed with exposure to purified mitochondrial-enriched fractions. Collectively, these observations suggest mitochondrial membranes heavily influence htt aggregation with implication for HD.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Pranav Jain
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Mark V Pinti
- Division of Exercise Physiology, West Virginia School of Medicine, Morgantown, WV 26506, United States; Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Chathuranga Siriwardhana
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - John M Hollander
- Division of Exercise Physiology, West Virginia School of Medicine, Morgantown, WV 26506, United States; Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States; Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, United States; Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, United States.
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14
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Groover SE, Adegbuyiro A, Fan CK, Hodges BL, Beasley M, Taylor K, Stonebraker AR, Siriwardhana C, Legleiter J. Macromolecular crowding in solution alters huntingtin interaction and aggregation at interfaces. Colloids Surf B Biointerfaces 2021; 206:111969. [PMID: 34246856 DOI: 10.1016/j.colsurfb.2021.111969] [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: 03/10/2021] [Revised: 06/16/2021] [Accepted: 07/05/2021] [Indexed: 10/20/2022]
Abstract
Huntington's disease (HD) is a fatal neurodegenerative disease caused by an extended polyglutamine (polyQ) domain within the first exon of the huntingtin protein (htt). PolyQ expansion directly invokes the formation of a heterogenous mixture of toxic htt aggregates, including fibrils and oligomers. While htt is a cytosolic protein, it also associates with numerous membranous surfaces within the cell, leading to altered organelle morphology and dysfunction. Here, the impact of macromolecular crowding on htt aggregation in bulk solution and at solid/liquid or membrane/liquid interfaces was investigated. Dextran, Ficoll, and polyethylene glycol (PEG) were used as crowding agents. In bulk solution, crowding enhanced the heterogeneity of non-fibrillar aggregate species formed in a crowder dependent manner. However, crowding agents interfered with the deposition of htt fibrils on mica, suggesting that a crowded aqueous phase influences the interaction of htt with interfaces. By use of in situ atomic force microcopy (AFM), the aggregation of htt directly at mica and bilayer interfaces was tracked. The predominate aggregates type observed to form at the mica interface was fibrillar, but oligomeric aggregates of various stabilities were also observed. Crowding in the aqueous phase suppressed deposition and formation of htt aggregates on mica. In contrast, the addition of crowders enhanced deposition of htt aggregates onto supported total brain lipid extract (TBLE) bilayers. Different crowding agents led to distinct htt aggregates on supported bilayers with unique morphological impact on bilayer integrity. Collectively, these observations point to the complexity of htt aggregation at interfaces and that crowding in the aqueous phase profoundly influences this process.
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Affiliation(s)
- Sharon E Groover
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Caleb K Fan
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Breanna L Hodges
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Katelyn Taylor
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Chathuranga Siriwardhana
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, United States; Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, United States; Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, United States.
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15
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Diociaiuti M, Bonanni R, Cariati I, Frank C, D’Arcangelo G. Amyloid Prefibrillar Oligomers: The Surprising Commonalities in Their Structure and Activity. Int J Mol Sci 2021; 22:ijms22126435. [PMID: 34208561 PMCID: PMC8235680 DOI: 10.3390/ijms22126435] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
It has been proposed that a “common core” of pathologic pathways exists for the large family of amyloid-associated neurodegenerations, including Alzheimer’s, Parkinson’s, type II diabetes and Creutzfeldt–Jacob’s Disease. Aggregates of the involved proteins, independently from their primary sequence, induced neuron membrane permeabilization able to trigger an abnormal Ca2+ influx leading to synaptotoxicity, resulting in reduced expression of synaptic proteins and impaired synaptic transmission. Emerging evidence is now focusing on low-molecular-weight prefibrillar oligomers (PFOs), which mimic bacterial pore-forming toxins that form well-ordered oligomeric membrane-spanning pores. At the same time, the neuron membrane composition and its chemical microenvironment seem to play a pivotal role. In fact, the brain of AD patients contains increased fractions of anionic lipids able to favor cationic influx. However, up to now the existence of a specific “common structure” of the toxic aggregate, and a “common mechanism” by which it induces neuronal damage, synaptotoxicity and impaired synaptic transmission, is still an open hypothesis. In this review, we gathered information concerning this hypothesis, focusing on the proteins linked to several amyloid diseases. We noted commonalities in their structure and membrane activity, and their ability to induce Ca2+ influx, neurotoxicity, synaptotoxicity and impaired synaptic transmission.
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Affiliation(s)
- Marco Diociaiuti
- Centro Nazionale Malattie Rare, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
- Correspondence:
| | - Roberto Bonanni
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy; (R.B.); (G.D.)
| | - Ida Cariati
- PhD in Medical-Surgical Biotechnologies and Translational Medicine, Department of Clinical Sciences and Translational Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Claudio Frank
- UniCamillus-Saint Camillus International University of Health Sciences, Via di Sant’Alessandro 8, 00131 Rome, Italy;
| | - Giovanna D’Arcangelo
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy; (R.B.); (G.D.)
- Centre of Space Bio-Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy
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16
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Babbi G, Savojardo C, Martelli PL, Casadio R. Huntingtin: A Protein with a Peculiar Solvent Accessible Surface. Int J Mol Sci 2021; 22:ijms22062878. [PMID: 33809039 PMCID: PMC8001614 DOI: 10.3390/ijms22062878] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 11/30/2022] Open
Abstract
Taking advantage of the last cryogenic electron microscopy structure of human huntingtin, we explored with computational methods its physicochemical properties, focusing on the solvent accessible surface of the protein and highlighting a quite interesting mix of hydrophobic and hydrophilic patterns, with the prevalence of the latter ones. We then evaluated the probability of exposed residues to be in contact with other proteins, discovering that they tend to cluster in specific regions of the protein. We then found that the remaining portions of the protein surface can contain calcium-binding sites that we propose here as putative mediators for the protein to interact with membranes. Our findings are justified in relation to the present knowledge of huntingtin functional annotation.
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Affiliation(s)
- Giulia Babbi
- Biocomputing Group, University of Bologna, Via San Giacomo 9/2, 40126 Bologna, Italy; (G.B.); (C.S.); (R.C.)
| | - Castrense Savojardo
- Biocomputing Group, University of Bologna, Via San Giacomo 9/2, 40126 Bologna, Italy; (G.B.); (C.S.); (R.C.)
| | - Pier Luigi Martelli
- Biocomputing Group, University of Bologna, Via San Giacomo 9/2, 40126 Bologna, Italy; (G.B.); (C.S.); (R.C.)
- Correspondence: ; Tel.: +39-051-2094005
| | - Rita Casadio
- Biocomputing Group, University of Bologna, Via San Giacomo 9/2, 40126 Bologna, Italy; (G.B.); (C.S.); (R.C.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, Via Giovanni Amendola 122/O, 70126 Bari, Italy
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17
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Hunter M, Demarais NJ, Faull RLM, Grey AC, Curtis MA. An imaging mass spectrometry atlas of lipids in the human neurologically normal and Huntington's disease caudate nucleus. J Neurochem 2021; 157:2158-2172. [PMID: 33606279 DOI: 10.1111/jnc.15325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/25/2021] [Accepted: 02/17/2021] [Indexed: 12/24/2022]
Abstract
Huntington's disease (HD) is a fatal disorder associated with germline trinucleotide repeat expansions in the HTT gene and characterised by striatal neurodegeneration. No efficacious interventions are available for HD, highlighting a major unmet medical need. The molecular mechanisms underlying HD are incompletely understood despite its monogenic aetiology. However, direct interactions between HTT and membrane lipids suggest that lipidomic perturbations may be implicated in the neuropathology of HD. In this study, we employed matrix-assisted laser desorption/ionisation imaging mass spectrometry (MALDI-IMS) to generate a comprehensive, unbiased and spatially resolved lipidomic atlas of the caudate nucleus (CN) in human post-mortem tissue from neurologically normal (n = 10) and HD (n = 13) subjects. Fourier transform-ion cyclotron resonance mass spectrometry and liquid chromatography-tandem mass spectrometry were used for lipid assignment. Lipidomic specialisation was observed in the grey and white matter constituents of the CN and these features were highly conserved between subjects. While the majority of lipid species were highly conserved in HD, compared to age-matched controls, CN specimens from HD cases in our cohort spanning a range of neuropathological grades showed a lower focal abundance of the neuroprotective docosahexaenoic and adrenic acids, several cardiolipins, the ganglioside GM1 and glycerophospholipids with long polyunsaturated fatty acyls. HD cases showed a higher focal abundance of several sphingomyelins and glycerophospholipids with shorter monosaturated fatty acyls. Moreover, we demonstrate that MALDI-IMS is tractable as a primary discovery modality comparing heterogeneous human brain tissue, provided that appropriate statistical approaches are adopted. Our findings support further investigation into the potential role of lipidomic aberrations in HD.
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Affiliation(s)
- Mandana Hunter
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Nicholas J Demarais
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Angus C Grey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
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18
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Groover SE, Beasley M, Ramamurthy V, Legleiter J. Phosphomimetic Mutations Impact Huntingtin Aggregation in the Presence of a Variety of Lipid Systems. Biochemistry 2020; 59:4681-4693. [PMID: 33256402 DOI: 10.1021/acs.biochem.0c00788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of a polyglutamine (polyQ) tract in the first exon of the htt protein (htt). PolyQ expansion triggers the aggregation of htt into a variety of structures, including oligomers and fibrils. This aggregation is impacted by the first 17 N-terminal amino acids (Nt17) of htt that directly precedes the polyQ domain. Beyond impacting aggregation, Nt17 associates with lipid membranes by forming an amphipathic α-helix. Post-translational modifications within Nt17 are known to modify HD pathology, and in particular, phosphorylation at T3, S13, and/or S16 retards fibrillization and ameliorates the phenotype in HD models. Due to Nt17's propensity to interact with lipid membranes, the impact of introducing phosphomimetic mutations (T3D, S13D, and S16D) into htt-exon1 on aggregation in the presence of a variety of model lipid membranes (total brain lipid extract, 1-palmitoyl-2-oleoyl-glycero-3-phosphatidylcholine, and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1'-rac-glycerol) was investigated. Phosphomimetic mutations altered htt's interaction with and aggregation in the presence of lipids; however, this was dependent on the lipid system.
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Affiliation(s)
- Sharon E Groover
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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19
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Cholesteryl ester levels are elevated in the caudate and putamen of Huntington's disease patients. Sci Rep 2020; 10:20314. [PMID: 33219259 PMCID: PMC7680097 DOI: 10.1038/s41598-020-76973-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/04/2020] [Indexed: 11/17/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative illness caused by a mutation in the huntingtin gene (HTT) and subsequent protein (mhtt), to which the brain shows a region-specific vulnerability. Disturbances in neural cholesterol metabolism are established in HD human, murine and cell studies; however, cholesteryl esters (CE), which store and transport cholesterol in the brain, have not been investigated in human studies. This study aimed to identify region-specific alterations in the concentrations of CE in HD. The Victorian Brain Bank provided post-mortem tissue from 13 HD subjects and 13 age and sex-matched controls. Lipids were extracted from the caudate, putamen and cerebellum, and CE were quantified using targeted mass spectrometry. ACAT 1 protein expression was measured by western blot. CE concentrations were elevated in HD caudate and putamen compared to controls, with the elevation more pronounced in the caudate. No differences in the expression of ACAT1 were identified in the striatum. No remarkable differences in CE were detected in HD cerebellum. The striatal region-specific differences in CE profiles indicate functional subareas of lipid disturbance in HD. The increased CE concentration may have been induced as a compensatory mechanism to reduce cholesterol accumulation.
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20
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Lipid headgroups alter huntingtin aggregation on membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183497. [PMID: 33130095 DOI: 10.1016/j.bbamem.2020.183497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022]
Abstract
Huntington's Disease is a fatal neurodegenerative disorder caused by expansion of a glutamine repeat region (polyQ) beyond a critical threshold within exon1 of the huntingtin protein (htt). As a consequence of polyQ expansion, htt associates into a variety of aggregate species that are thought to underlie cellular toxicity. Within cells, htt associates with numerous membranous organelles and surfaces that exert influence on the aggregation process. In particular, the first 17 amino acids at the N-terminus of htt (Nt17) serve as a lipid-binding domain that is intrinsically disordered in bulk solution but adopts an amphipathic α-helical structure upon binding membranes. Beyond this, Nt17 is implicated in initiating htt fibrillization. As the interaction between Nt17 and lipid membranes is likely influenced by lipid properties, the impact of lipid headgroups on htt-exon1 aggregation, membrane activity, and the ability to form protein:lipid complexes was determined. Htt-exon1 with a disease-length polyQ domain (46Q) was exposed to lipid vesicles comprised of lipids with either zwitterionic (POPC and POPE) or anionic (POPG and POPS) headgroups. With zwitterionic head groups, large lipid to peptide ratios were required to have a statistically significant impact on htt aggregation. Anionic lipids enhanced htt fibrillization, even at low lipid:protein ratios, and this was accompanied by changes in aggregate morphology. Despite the larger impact of anionic lipids, htt-exon1(46Q) was more membrane active with zwitterionic lipid systems. The ability of Nt17 to form complexes with lipids was also mediated by lipid headgroups as zwitterionic ionic lipids more readily associated with multimeric forms of Nt17 in comparison with anionic lipids. Collectively, these results highlight the complexity of htt/membrane interactions and the resulting impact on the aggregation process.
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21
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Sipione S, Monyror J, Galleguillos D, Steinberg N, Kadam V. Gangliosides in the Brain: Physiology, Pathophysiology and Therapeutic Applications. Front Neurosci 2020; 14:572965. [PMID: 33117120 PMCID: PMC7574889 DOI: 10.3389/fnins.2020.572965] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Gangliosides are glycosphingolipids highly abundant in the nervous system, and carry most of the sialic acid residues in the brain. Gangliosides are enriched in cell membrane microdomains ("lipid rafts") and play important roles in the modulation of membrane proteins and ion channels, in cell signaling and in the communication among cells. The importance of gangliosides in the brain is highlighted by the fact that loss of function mutations in ganglioside biosynthetic enzymes result in severe neurodegenerative disorders, often characterized by very early or childhood onset. In addition, changes in the ganglioside profile (i.e., in the relative abundance of specific gangliosides) were reported in healthy aging and in common neurological conditions, including Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), stroke, multiple sclerosis and epilepsy. At least in HD, PD and in some forms of epilepsy, experimental evidence strongly suggests a potential role of gangliosides in disease pathogenesis and potential treatment. In this review, we will summarize ganglioside functions that are crucial to maintain brain health, we will review changes in ganglioside levels that occur in major neurological conditions and we will discuss their contribution to cellular dysfunctions and disease pathogenesis. Finally, we will review evidence of the beneficial roles exerted by gangliosides, GM1 in particular, in disease models and in clinical trials.
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Affiliation(s)
- Simonetta Sipione
- Department of Pharmacology, Faculty of Medicine and Dentistry, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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22
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Sedighi F, Adegbuyiro A, Legleiter J. SUMOylation Prevents Huntingtin Fibrillization and Localization onto Lipid Membranes. ACS Chem Neurosci 2020; 11:328-343. [PMID: 31880908 DOI: 10.1021/acschemneuro.9b00509] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD), a genetic neurodegenerative disease, is caused by an expanded polyglutamine (polyQ) domain in the first exon of the huntingtin protein (htt). PolyQ expansion destabilizes protein structure, resulting in aggregation into a variety of oligomers, protofibrils, and fibrils. Beyond the polyQ domain, adjacent protein sequences influence the aggregation process. Specifically, the first 17 N-terminal amino acids (Nt17) directly preceding the polyQ domain promote the formation of α-helix-rich oligomers that represent intermediate species associated with fibrillization. Due to its propensity to form an amphipathic α-helix, Nt17 also facilitates lipid binding. Three lysine residues (K6, K9, and K15) within Nt17 can be SUMOylated, which modifies htt's accumulation and toxicity within cells in a variety of HD models. The impact of SUMOylation on htt aggregation and direct interaction with lipid membranes was investigated. SUMOylation of htt-exon1 inhibited fibril formation while promoting larger, amorphous aggregate species. These amorphous aggregates were SDS soluble but nonetheless exhibited levels of β-sheet structure similar to that of htt-exon1 fibrils. In addition, SUMOylation prevented htt binding, aggregation, and accumulation on model lipid bilayers comprised of total brain lipid extract. Collectively, these observations demonstrate that SUMOylation promotes a distinct htt aggregation pathway that may affect htt toxicity.
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Affiliation(s)
- Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
- Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
- Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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23
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Beasley M, Stonebraker AR, Hasan I, Kapp KL, Liang BJ, Agarwal G, Groover S, Sedighi F, Legleiter J. Lipid Membranes Influence the Ability of Small Molecules To Inhibit Huntingtin Fibrillization. Biochemistry 2019; 58:4361-4373. [PMID: 31608620 DOI: 10.1021/acs.biochem.9b00739] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease (HD), are associated with specific proteins aggregating and depositing within tissues and/or cellular compartments. The aggregation of these proteins is characterized by the formation of extended, β-sheet rich fibrils, termed amyloid. In addition, a variety of other aggregate species also form, including oligomers and protofibrils. Specifically, HD is caused by the aggregation of the huntingtin (htt) protein that contains an expanded polyglutamine domain. Due to the link between protein aggregation and disease, small molecule aggregation inhibitors have been pursued as potential therapeutic agents. Two such small molecules are epigallocatechin 3-gallate (EGCG) and curcumin, both of which inhibit the fibril formation of several amyloid-forming proteins. However, amyloid formation is a complex process that is strongly influenced by the protein's environment, leading to distinct aggregation pathways. Thus, changes in the protein's environment may alter the effectiveness of aggregation inhibitors. A well-known modulator of amyloid formation is lipid membranes. Here, we investigated if the presence of lipid vesicles altered the ability of EGCG or curcumin to modulate htt aggregation and influence the interaction of htt with lipid membranes. The presence of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine or total brain lipid extract vesicles prevented the curcumin from inhibiting htt fibril formation. In contrast, EGCG's inhibition of htt fibril formation persisted in the presence of lipids. Collectively, these results highlight the complexity of htt aggregation and demonstrate that the presence of lipid membranes is a key modifier of the ability of small molecules to inhibit htt fibril formation.
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Affiliation(s)
- Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Iraj Hasan
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Kathryn L Kapp
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Barry J Liang
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Garima Agarwal
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Sharon Groover
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States.,Rockefeller Neurosciences Institute , West Virginia University , 1 Medical Center Drive , P.O. Box 9303, Morgantown , West Virginia 26505 , United States.,Department of Neuroscience , West Virginia University , 1 Medical Center Drive , P.O. Box 9303, Morgantown , West Virginia 26505 , United States
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24
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Herrera F, Branco-Santos J, Outeiro T. Threonine 3 regulates Serine 13/16 phosphorylation in the huntingtin exon 1. ACTA ACUST UNITED AC 2019. [DOI: 10.19185/matters.201905000005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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25
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Levy GR, Shen K, Gavrilov Y, Smith PES, Levy Y, Chan R, Frydman J, Frydman L. Huntingtin's N-Terminus Rearrangements in the Presence of Membranes: A Joint Spectroscopic and Computational Perspective. ACS Chem Neurosci 2019; 10:472-481. [PMID: 30149694 DOI: 10.1021/acschemneuro.8b00353] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Huntington's disease is a neurodegenerative disorder resulting from an expanded polyglutamine (polyQ) repeat of the Huntingtin (Htt) protein. Affected tissues often contain aggregates of the N-terminal Htt exon 1 (Htt-Ex1) fragment. The N-terminal N17 domain proximal to the polyQ tract is key to enhance aggregation and modulate Htt toxicity. Htt-Ex1 is intrinsically disordered, yet it has been postulated that under physiological conditions membranes induce the N17 to adopt an α-helical structure, which then plays a key role in regulating Htt protein aggregation. The present study leverages the recently available assignment of NMR peaks in an N17Q17 construct, in order to provide a look into the changes occurring in vitro upon exposing this fragment to various brain extract fragments as well as to synthetic bilayers. Residue-specific changes were observed by 3D HNCO NMR, whose nature was further clarified with ancillary CD and aggregation studies, as well as with molecular dynamic calculations. From this combination of measurements and computations, a unified picture emerges, whereby transient structures consisting of α-helices spanning a fraction of the N17 residues form during N17Q17-membrane interactions. These interactions are fairly dynamic, but they qualitatively mimic more rigid variants that have been discussed in the literature. The nature of these interactions and their potential influence on the aggregation process of these kinds of constructs under physiological conditions are briefly assessed.
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Affiliation(s)
| | - Koning Shen
- Department of Biology, Stanford University, Stanford, California 94305, United States
| | | | | | | | - Rebecca Chan
- Department of Biology, Stanford University, Stanford, California 94305, United States
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California 94305, United States
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26
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Sahoo A, Matysiak S. Computational insights into lipid assisted peptide misfolding and aggregation in neurodegeneration. Phys Chem Chem Phys 2019; 21:22679-22694. [DOI: 10.1039/c9cp02765c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An overview of recent advances in computational investigation of peptide–lipid interactions in neurodegeneration – Alzheimer's, Parkinson's and Huntington's disease.
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Affiliation(s)
- Abhilash Sahoo
- Biophysics Program
- Institute of Physical Science and Technology
- University of Maryland
- College Park
- USA
| | - Silvina Matysiak
- Biophysics Program
- Institute of Physical Science and Technology
- University of Maryland
- College Park
- USA
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27
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Boussicault L, Kacher R, Lamazière A, Vanhoutte P, Caboche J, Betuing S, Potier MC. CYP46A1 protects against NMDA-mediated excitotoxicity in Huntington's disease: Analysis of lipid raft content. Biochimie 2018; 153:70-79. [DOI: 10.1016/j.biochi.2018.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/27/2018] [Indexed: 12/15/2022]
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28
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Ceccon A, Schmidt T, Tugarinov V, Kotler SA, Schwieters CD, Clore GM. Interaction of Huntingtin Exon-1 Peptides with Lipid-Based Micellar Nanoparticles Probed by Solution NMR and Q-Band Pulsed EPR. J Am Chem Soc 2018; 140:6199-6202. [PMID: 29727175 DOI: 10.1021/jacs.8b02619] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipid-based micellar nanoparticles promote aggregation of huntingtin exon-1 peptides. Here we characterize the interaction of two such peptides, httNTQ 7 and httNTQ 10 comprising the N-terminal amphiphilic domain of huntingtin followed by 7 and 10 glutamine repeats, respectively, with 8 nm lipid micelles using NMR chemical exchange saturation transfer (CEST), circular dichroism and pulsed Q-band EPR. Exchange between free and micelle-bound httNTQ n peptides occurs on the millisecond time scale with a KD ∼ 0.5-1 mM. Upon binding micelles, residues 1-15 adopt a helical conformation. Oxidation of Met7 to a sulfoxide reduces the binding affinity for micelles ∼3-4-fold and increases the length of the helix by a further two residues. A structure of the bound monomer unit is calculated from the backbone chemical shifts of the micelle-bound state obtained from CEST. Pulsed Q-band EPR shows that a monomer-dimer equilibrium exists on the surface of the micelles and that the two helices of the dimer adopt a parallel orientation, thereby bringing two disordered polyQ tails into close proximity which may promote aggregation upon dissociation from the micelle surface.
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Affiliation(s)
- Alberto Ceccon
- Laboratory of Chemical Physics , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland 20892-520 , United States
| | - Thomas Schmidt
- Laboratory of Chemical Physics , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland 20892-520 , United States
| | - Vitali Tugarinov
- Laboratory of Chemical Physics , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland 20892-520 , United States
| | - Samuel A Kotler
- Laboratory of Chemical Physics , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland 20892-520 , United States
| | - Charles D Schwieters
- Imaging Sciences Laboratory , Center for Information Technology, National Institutes of Health , Bethesda , Maryland 20892-5624 , United States
| | - G Marius Clore
- Laboratory of Chemical Physics , National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda , Maryland 20892-520 , United States
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29
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Caterino M, Squillaro T, Montesarchio D, Giordano A, Giancola C, Melone MAB. Huntingtin protein: A new option for fixing the Huntington's disease countdown clock. Neuropharmacology 2018. [PMID: 29526547 DOI: 10.1016/j.neuropharm.2018.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Huntington's disease is a dreadful, incurable disorder. It springs from the autosomal dominant mutation in the first exon of the HTT gene, which encodes for the huntingtin protein (HTT) and results in progressive neurodegeneration. Thus far, all the attempted approaches to tackle the mutant HTT-induced toxicity causing this disease have failed. The mutant protein comes with the aberrantly expanded poly-glutamine tract. It is primarily to blame for the build-up of β-amyloid-like HTT aggregates, deleterious once broadened beyond the critical ∼35-37 repeats threshold. Recent experimental findings have provided valuable information on the molecular basis underlying this HTT-driven neurodegeneration. These findings indicate that the poly-glutamine siding regions and many post-translation modifications either abet or counter the poly-glutamine tract. This review provides an overall, up-to-date insight into HTT biophysics and structural biology, particularly discussing novel pharmacological options to specifically target the mutated protein and thus inhibit its functions and toxicity.
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Affiliation(s)
- Marco Caterino
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy
| | - Tiziana Squillaro
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Daniela Montesarchio
- InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA; Department of Medicine, Surgery and Neuroscience University of Siena, Siena, Italy
| | - Concetta Giancola
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy.
| | - Mariarosa A B Melone
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
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30
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Pandey NK, Isas JM, Rawat A, Lee RV, Langen J, Pandey P, Langen R. The 17-residue-long N terminus in huntingtin controls stepwise aggregation in solution and on membranes via different mechanisms. J Biol Chem 2018; 293:2597-2605. [PMID: 29282287 PMCID: PMC5818184 DOI: 10.1074/jbc.m117.813667] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/19/2017] [Indexed: 01/05/2023] Open
Abstract
Aggregation of huntingtin protein arising from expanded polyglutamine (polyQ) sequences in the exon-1 region of mutant huntingtin plays a central role in the pathogenesis of Huntington's disease. The huntingtin aggregation pathways are of therapeutic and diagnostic interest, but obtaining critical information from the physiologically relevant htt exon-1 (Httex1) protein has been challenging. Using biophysical techniques and an expression and purification protocol that generates clean, monomeric Httex1, we identified and mapped three distinct aggregation pathways: 1) unseeded in solution; 2) seeded in solution; and 3) membrane-mediated. In solution, aggregation proceeded in a highly stepwise manner, in which the individual domains (N terminus containing 17 amino acids (N17), polyQ, and proline-rich domain (PRD)) become ordered at very different rates. The aggregation was initiated by an early oligomer requiring a pathogenic, expanded Gln length and N17 α-helix formation. In the second phase, β-sheet forms in the polyQ. The slowest step is the final structural maturation of the PRD. This stepwise mechanism could be bypassed by seeding, which potently accelerated aggregation and was a prerequisite for prion-like spreading in vivo Remarkably, membranes could catalyze aggregation even more potently than seeds, in a process that caused significant membrane damage. The N17 governed membrane-mediated aggregation by anchoring Httex1 to the membrane, enhancing local concentration and promoting collision via two-dimensional diffusion. Considering its central roles in solution and in membrane-mediated aggregation, the N17 represents an attractive target for inhibiting multiple pathways. Our approach should help evaluate such inhibitors and identify diagnostic markers for the misfolded forms identified here.
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Affiliation(s)
- Nitin K Pandey
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - J Mario Isas
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Anoop Rawat
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Rachel V Lee
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Jennifer Langen
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Priyatama Pandey
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Ralf Langen
- From the Departments of Physiology and Neuroscience and of Biochemistry and Molecular Medicine. Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
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31
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Chaibva M, Gao X, Jain P, Campbell WA, Frey SL, Legleiter J. Sphingomyelin and GM1 Influence Huntingtin Binding to, Disruption of, and Aggregation on Lipid Membranes. ACS OMEGA 2018; 3:273-285. [PMID: 29399649 PMCID: PMC5793032 DOI: 10.1021/acsomega.7b01472] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/25/2017] [Indexed: 05/09/2023]
Abstract
Huntington disease (HD) is an inherited neurodegenerative disease caused by the expansion beyond a critical threshold of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ promotes the formation of a variety of oligomeric and fibrillar aggregates of htt that accumulate into the hallmark proteinaceous inclusion bodies associated with HD. htt is also highly associated with numerous cellular and subcellular membranes that contain a variety of lipids. As lipid homeostasis and metabolism abnormalities are observed in HD patients, we investigated how varying both the sphingomyelin (SM) and ganglioside (GM1) contents modifies the interactions between htt and lipid membranes. SM composition is altered in HD, and GM1 has been shown to have protective effects in animal models of HD. A combination of Langmuir trough monolayer techniques, vesicle permeability and binding assays, and in situ atomic force microscopy (AFM) were used to directly monitor the interaction of a model, synthetic htt peptide and a full-length htt-exon1 recombinant protein with model membranes comprised of total brain lipid extract (TBLE) and varying amounts of exogenously added SM or GM1. The addition of either SM or GM1 decreased htt insertion into the lipid monolayers. However, TBLE vesicles with an increased SM content were more susceptible to htt-induced permeabilization, whereas GM1 had no effect on permeablization. Pure TBLE bilayers and TBLE bilayers enriched with GM1 developed regions of roughened, granular morphologies upon exposure to htt-exon1, but plateau-like domains with a smoother appearance formed in bilayers enriched with SM. Oligomeric aggregates were observed on all bilayer systems regardless of induced morphology. Collectively, these observations suggest that the lipid composition and its subsequent effects on membrane material properties strongly influence htt binding and aggregation on lipid membranes.
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Affiliation(s)
- Maxmore Chaibva
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Xiang Gao
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Pranav Jain
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Warren A. Campbell
- Department
of Chemistry, Gettysburg College, 300 N. Washington Avenue, Campus Box 0393, Gettysburg, Pennsylvania 17325, United States
| | - Shelli L. Frey
- Department
of Chemistry, Gettysburg College, 300 N. Washington Avenue, Campus Box 0393, Gettysburg, Pennsylvania 17325, United States
- E-mail: . Phone: 717-337-6259 (S.L.F.)
| | - Justin Legleiter
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
- Blanchette
Rockefeller Neurosciences Institutes, West
Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States
- E-mail: . Phone: 304-293-0175 (J.L.)
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32
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Al-Ramahi I, Giridharan SSP, Chen YC, Patnaik S, Safren N, Hasegawa J, de Haro M, Wagner Gee AK, Titus SA, Jeong H, Clarke J, Krainc D, Zheng W, Irvine RF, Barmada S, Ferrer M, Southall N, Weisman LS, Botas J, Marugan JJ. Inhibition of PIP4Kγ ameliorates the pathological effects of mutant huntingtin protein. eLife 2017; 6:29123. [PMID: 29256861 PMCID: PMC5743427 DOI: 10.7554/elife.29123] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/13/2017] [Indexed: 12/15/2022] Open
Abstract
The discovery of the causative gene for Huntington’s disease (HD) has promoted numerous efforts to uncover cellular pathways that lower levels of mutant huntingtin protein (mHtt) and potentially forestall the appearance of HD-related neurological defects. Using a cell-based model of pathogenic huntingtin expression, we identified a class of compounds that protect cells through selective inhibition of a lipid kinase, PIP4Kγ. Pharmacological inhibition or knock-down of PIP4Kγ modulates the equilibrium between phosphatidylinositide (PI) species within the cell and increases basal autophagy, reducing the total amount of mHtt protein in human patient fibroblasts and aggregates in neurons. In two Drosophila models of Huntington’s disease, genetic knockdown of PIP4K ameliorated neuronal dysfunction and degeneration as assessed using motor performance and retinal degeneration assays respectively. Together, these results suggest that PIP4Kγ is a druggable target whose inhibition enhances productive autophagy and mHtt proteolysis, revealing a useful pharmacological point of intervention for the treatment of Huntington’s disease, and potentially for other neurodegenerative disorders.
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Affiliation(s)
- Ismael Al-Ramahi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | | | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Samarjit Patnaik
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Junya Hasegawa
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Maria de Haro
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Amanda K Wagner Gee
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Steven A Titus
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Hyunkyung Jeong
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jonathan Clarke
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Dimitri Krainc
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Wei Zheng
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Robin F Irvine
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Noel Southall
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Lois S Weisman
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Juan Botas
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Juan Jose Marugan
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
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33
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Bäuerlein FJB, Saha I, Mishra A, Kalemanov M, Martínez-Sánchez A, Klein R, Dudanova I, Hipp MS, Hartl FU, Baumeister W, Fernández-Busnadiego R. In Situ Architecture and Cellular Interactions of PolyQ Inclusions. Cell 2017; 171:179-187.e10. [PMID: 28890085 DOI: 10.1016/j.cell.2017.08.009] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/30/2017] [Accepted: 08/07/2017] [Indexed: 02/06/2023]
Abstract
Expression of many disease-related aggregation-prone proteins results in cytotoxicity and the formation of large intracellular inclusion bodies. To gain insight into the role of inclusions in pathology and the in situ structure of protein aggregates inside cells, we employ advanced cryo-electron tomography methods to analyze the structure of inclusions formed by polyglutamine (polyQ)-expanded huntingtin exon 1 within their intact cellular context. In primary mouse neurons and immortalized human cells, polyQ inclusions consist of amyloid-like fibrils that interact with cellular endomembranes, particularly of the endoplasmic reticulum (ER). Interactions with these fibrils lead to membrane deformation, the local impairment of ER organization, and profound alterations in ER membrane dynamics at the inclusion periphery. These results suggest that aberrant interactions between fibrils and endomembranes contribute to the deleterious cellular effects of protein aggregation. VIDEO ABSTRACT.
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Affiliation(s)
- Felix J B Bäuerlein
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Itika Saha
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Archana Mishra
- Department of Molecules, Signaling, and Development, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Maria Kalemanov
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Graduate School of Quantitative Biosciences Munich, 81337 Munich, Germany
| | - Antonio Martínez-Sánchez
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Rüdiger Klein
- Department of Molecules, Signaling, and Development, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 80336 Munich, Germany
| | - Irina Dudanova
- Department of Molecules, Signaling, and Development, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Mark S Hipp
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 80336 Munich, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 80336 Munich, Germany.
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
| | - Rubén Fernández-Busnadiego
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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In Situ Atomic Force Microscopy Studies on Nucleation and Self-Assembly of Biogenic and Bio-Inspired Materials. MINERALS 2017. [DOI: 10.3390/min7090158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Mutant Huntingtin Is Secreted via a Late Endosomal/Lysosomal Unconventional Secretory Pathway. J Neurosci 2017; 37:9000-9012. [PMID: 28821645 DOI: 10.1523/jneurosci.0118-17.2017] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/26/2017] [Accepted: 08/09/2017] [Indexed: 12/22/2022] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by the expansion of a CAG triplet in the gene encoding for huntingtin (Htt). The resulting mutant protein (mHtt) with extended polyglutamine (polyQ) sequence at the N terminus leads to neuronal degeneration both in a cell-autonomous and a non-cell-autonomous manner. Recent studies identified mHtt in the extracellular environment and suggested that its spreading contributes to toxicity, but the mechanism of mHtt release from the cell of origin remains unknown. In this study, we performed a comprehensive, unbiased analysis of secretory pathways and identified an unconventional lysosomal pathway as an important mechanism for mHtt secretion in mouse neuroblastoma and striatal cell lines, as well as in primary neurons. mHtt secretion was dependent on synaptotagmin 7, a regulator of lysosomal secretion, and inhibited by chemical ablation of late endosomes/lysosomes, suggesting a lysosomal secretory pattern. mHtt was targeted preferentially to the late endosomes/lysosomes compared with wild-type Htt. Importantly, we found that late endosomal/lysosomal targeting and secretion of mHtt could be inhibited efficiently by the phosphatidylinositol 3-kinase and neutral sphingomyelinase chemical inhibitors, Ly294002 and GW4869, respectively. Together, our data suggest a lysosomal mechanism of mHtt secretion and offer potential strategies for pharmacological modulation of its neuronal secretion.SIGNIFICANCE STATEMENT This is the first study examining the mechanism of mutant huntingtin (mHTT) secretion in an unbiased manner. We found that the protein is secreted via a late endosomal/lysosomal unconventional secretory pathway. Moreover, mHtt secretion can be reduced significantly by phosphatidylinositol 3-kinase and neutral sphingomyelinase inhibitors. Understanding and manipulating the secretion of mHtt is important because of its potentially harmful propagation in the brain.
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Shrivastava AN, Aperia A, Melki R, Triller A. Physico-Pathologic Mechanisms Involved in Neurodegeneration: Misfolded Protein-Plasma Membrane Interactions. Neuron 2017; 95:33-50. [DOI: 10.1016/j.neuron.2017.05.026] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 05/12/2017] [Accepted: 05/19/2017] [Indexed: 12/12/2022]
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37
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Chaibva M, Jawahery S, Pilkington AW, Arndt JR, Sarver O, Valentine S, Matysiak S, Legleiter J. Acetylation within the First 17 Residues of Huntingtin Exon 1 Alters Aggregation and Lipid Binding. Biophys J 2017; 111:349-362. [PMID: 27463137 DOI: 10.1016/j.bpj.2016.06.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 02/06/2023] Open
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disorder caused by an expanded polyglutamine (polyQ) domain near the N-terminus of the huntingtin (htt) protein. Expanded polyQ leads to htt aggregation. The first 17 amino acids (Nt(17)) in htt comprise a lipid-binding domain that undergoes a number of posttranslational modifications that can modulate htt toxicity and subcellular localization. As there are three lysines within Nt(17), we evaluated the impact of lysine acetylation on htt aggregation in solution and on model lipid bilayers. Acetylation of htt-exon1(51Q) and synthetic truncated htt-exon 1 mimicking peptides (Nt(17)-Q35-P10-KK) was achieved using a selective covalent label, sulfo-N-hydroxysuccinimide (NHSA). With this treatment, all three lysine residues (K6, K9, and K15) in Nt(17) were significantly acetylated. N-terminal htt acetylation retarded fibril formation in solution and promoted the formation of larger globular aggregates. Acetylated htt also bound lipid membranes and disrupted the lipid bilayer morphology less aggressively compared with the wild-type. Computational studies provided mechanistic insights into how acetylation alters the interaction of Nt(17) with lipid membranes. Our results highlight that N-terminal acetylation influences the aggregation of htt and its interaction with lipid bilayers.
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Affiliation(s)
- Maxmore Chaibva
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Sudi Jawahery
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Albert W Pilkington
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - James R Arndt
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Olivia Sarver
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Stephen Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Silvina Matysiak
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland; Biophysics Program, Institute for Physical Chemistry and Technology, University of Maryland, College Park, Maryland.
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia; NanoSAFE, West Virginia University, Morgantown, West Virginia; Center for Neurosciences, West Virginia University, Morgantown, West Virginia.
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38
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Adegbuyiro A, Sedighi F, Pilkington AW, Groover S, Legleiter J. Proteins Containing Expanded Polyglutamine Tracts and Neurodegenerative Disease. Biochemistry 2017; 56:1199-1217. [PMID: 28170216 DOI: 10.1021/acs.biochem.6b00936] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several hereditary neurological and neuromuscular diseases are caused by an abnormal expansion of trinucleotide repeats. To date, there have been 10 of these trinucleotide repeat disorders associated with an expansion of the codon CAG encoding glutamine (Q). For these polyglutamine (polyQ) diseases, there is a critical threshold length of the CAG repeat required for disease, and further expansion beyond this threshold is correlated with age of onset and symptom severity. PolyQ expansion in the translated proteins promotes their self-assembly into a variety of oligomeric and fibrillar aggregate species that accumulate into the hallmark proteinaceous inclusion bodies associated with each disease. Here, we review aggregation mechanisms of proteins with expanded polyQ-tracts, structural consequences of expanded polyQ ranging from monomers to fibrillar aggregates, the impact of protein context and post-translational modifications on aggregation, and a potential role for lipid membranes in aggregation. As the pathogenic mechanisms that underlie these disorders are often classified as either a gain of toxic function or loss of normal protein function, some toxic mechanisms associated with mutant polyQ tracts will also be discussed.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Albert W Pilkington
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Sharon Groover
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, 217 Clark Hall, West Virginia University , Morgantown, West Virginia 26506, United States.,Blanchette Rockefeller Neurosciences Institute, Robert C. Byrd Health Sciences Center, P.O. Box 9304, West Virginia University , Morgantown, West Virginia 26506, United States.,NanoSAFE, P.O. Box 6223, West Virginia University , Morgantown, West Virginia 26506, United States
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39
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Debnath K, Shekhar S, Kumar V, Jana NR, Jana NR. Efficient Inhibition of Protein Aggregation, Disintegration of Aggregates, and Lowering of Cytotoxicity by Green Tea Polyphenol-Based Self-Assembled Polymer Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2016; 8:20309-20318. [PMID: 27427935 DOI: 10.1021/acsami.6b06853] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Green tea polyphenol epigallocatechin-3-gallate (EGCG) is known for its antiamyloidogenic property, and it is observed that molecular EGCG binds with amyloid structure, redirects fibrillation kinetics, remodels mature fibril, and lowers the amyloid-derived toxicity. However, this unique property of EGCG is difficult to utilize because of their poor chemical stability and substandard bioavailability. Here we report a nanoparticle form of EGCG of 25 nm size (nano-EGCG) which is 10-100 times more efficient than molecular EGCG in inhibiting protein aggregation, disintegrating mature protein aggregates, and lowering amyloidogenic cytotoxicity. The most attractive advantage of nano-EGCG is that it efficiently protects neuronal cells from the toxic effect of extracellular amyloid beta or intracellular mutant huntingtin protein aggregates by preventing their aggregation. We found that the better performance of nano-EGCG is due to the combined effect of increased chemical stability of EGCG against degradation, stronger binding with protein aggregates, and efficient entry into the cell for interaction with aggregated protein structure. This result indicates that the nanoparticle form of antiamyloidogenic molecules can be more powerful in prevention and curing of protein aggregation derived diseases.
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Affiliation(s)
- Koushik Debnath
- Centre for Advanced Materials, Indian Association for the Cultivation of Science , Kolkata 700032, India
| | - Shashi Shekhar
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre , Manesar, Gurgaon 122051, India
| | - Vipendra Kumar
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre , Manesar, Gurgaon 122051, India
| | - Nihar R Jana
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre , Manesar, Gurgaon 122051, India
| | - Nikhil R Jana
- Centre for Advanced Materials, Indian Association for the Cultivation of Science , Kolkata 700032, India
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40
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Arndt JR, Chaibva M, Legleiter J. The emerging role of the first 17 amino acids of huntingtin in Huntington's disease. Biomol Concepts 2016; 6:33-46. [PMID: 25741791 DOI: 10.1515/bmc-2015-0001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/09/2015] [Indexed: 01/01/2023] Open
Abstract
Huntington's disease (HD) is caused by a polyglutamine (polyQ) domain that is expanded beyond a critical threshold near the N-terminus of the huntingtin (htt) protein, directly leading to htt aggregation. While full-length htt is a large (on the order of ∼350 kDa) protein, it is proteolyzed into a variety of N-terminal fragments that accumulate in oligomers, fibrils, and larger aggregates. It is clear that polyQ length is a key determinant of htt aggregation and toxicity. However, the flanking sequences around the polyQ domain, such as the first 17 amino acids on the N terminus (Nt17), influence aggregation, aggregate stability, influence other important biochemical properties of the protein and ultimately its role in pathogenesis. Here, we review the impact of Nt17 on htt aggregation mechanisms and kinetics, structural properties of Nt17 in both monomeric and aggregate forms, the potential role of posttranslational modifications (PTMs) that occur in Nt17 in HD, and the function of Nt17 as a membrane targeting domain.
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41
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Ho CS, Khadka NK, She F, Cai J, Pan J. Polyglutamine aggregates impair lipid membrane integrity and enhance lipid membrane rigidity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:661-70. [PMID: 26806158 DOI: 10.1016/j.bbamem.2016.01.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 10/22/2022]
Abstract
Lipid membranes are suggested as the primary target of amyloid aggregates. We study aggregates formed by a polyglutamine (polyQ) peptide, and their disruptive effect on lipid membranes. Using solution atomic force microscopy (AFM), we observe polyQ oligomers coexisting with short fibrils, which have a twisted morphology that likely corresponds to two intertwined oligomer strings. Fourier transform infrared spectroscopy reveals that the content of β-sheet enriched aggregates increases with incubation time. Using fluorescence microscopy, we find that exposure to polyQ aggregates results in deflated morphology of giant unilamellar vesicles. PolyQ aggregates induced membrane disruption is further substantiated by time-dependent calcein leakage from the interior to the exterior of lipid vesicles. Detailed structural and mechanical perturbations of lipid membranes are revealed by solution AFM. We find that membrane disruption by polyQ aggregates proceeds by a two-step process, involving partial and full disruption. In addition to height contrast, the resulting partially and fully disrupted bilayers have distinct rigidity and adhesion force properties compared to the intact bilayer. Specifically, the bilayer rigidity increases as the intact bilayer becomes partially and fully disrupted. Surprisingly, the adhesion force first decreases and then increases during the disruption process. By resolving individual fibrils deposited on bilayer surface, we show that both the length and the number of fibrils can increase with incubation time. Our results highlight that membrane disruption could be the molecular basis of polyQ aggregates induced cytotoxicity.
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Affiliation(s)
- Chian Sing Ho
- Department of Physics, University of South Florida, Tampa, FL 33620, United States
| | - Nawal K Khadka
- Department of Physics, University of South Florida, Tampa, FL 33620, United States
| | - Fengyu She
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620, United States.
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42
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Côté S, Binette V, Salnikov ES, Bechinger B, Mousseau N. Probing the Huntingtin 1-17 membrane anchor on a phospholipid bilayer by using all-atom simulations. Biophys J 2016; 108:1187-98. [PMID: 25762330 DOI: 10.1016/j.bpj.2015.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/18/2015] [Accepted: 02/02/2015] [Indexed: 12/12/2022] Open
Abstract
Mislocalization and aggregation of the huntingtin protein are related to Huntington's disease. Its first exon-more specifically the first 17 amino acids (Htt17)-is crucial for the physiological and pathological functions of huntingtin. It regulates huntingtin's activity through posttranslational modifications and serves as an anchor to membrane-containing organelles of the cell. Recently, structure and orientation of the Htt17 membrane anchor were determined using a combined solution and solid-state NMR approach. This prompted us to refine this model by investigating the dynamics and thermodynamics of this membrane anchor on a POPC bilayer using all-atom, explicit solvent molecular dynamics and Hamiltonian replica exchange. Our simulations are combined with various experimental measurements to generate a high-resolution atomistic model for the huntingtin Htt17 membrane anchor on a POPC bilayer. More precisely, we observe that the single α-helix structure is more stable in the phospholipid membrane than the NMR model obtained in the presence of dodecylphosphocholine detergent micelles. The resulting Htt17 monomer has its hydrophobic plane oriented parallel to the bilayer surface. Our results further unveil the key residues interacting with the membrane in terms of hydrogen bonds, salt-bridges, and nonpolar contributions. We also observe that Htt17 equilibrates at a well-defined insertion depth and that it perturbs the physical properties-order parameter, thickness, and area per lipid-of the bilayer in a manner that could favor its dimerization. Overall, our observations reinforce and refine the NMR measurements on the Htt17 membrane anchor segment of huntingtin that is of fundamental importance to its biological functions.
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Affiliation(s)
- Sébastien Côté
- Département de Physique and Groupe de Recherche sur les Protéines Membranaires, Université de Montréal, Montréal, Québec, Canada.
| | - Vincent Binette
- Département de Physique and Groupe de Recherche sur les Protéines Membranaires, Université de Montréal, Montréal, Québec, Canada
| | - Evgeniy S Salnikov
- Université de Strasbourg/Centre National de la Recherche Scientifique, UMR7177, Institut de Chimie, Strasbourg, France
| | - Burkhard Bechinger
- Université de Strasbourg/Centre National de la Recherche Scientifique, UMR7177, Institut de Chimie, Strasbourg, France
| | - Normand Mousseau
- Département de Physique and Groupe de Recherche sur les Protéines Membranaires, Université de Montréal, Montréal, Québec, Canada.
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43
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Gao X, Campbell WA, Chaibva M, Jain P, Leslie AE, Frey SL, Legleiter J. Cholesterol Modifies Huntingtin Binding to, Disruption of, and Aggregation on Lipid Membranes. Biochemistry 2015; 55:92-102. [PMID: 26652744 DOI: 10.1021/acs.biochem.5b00900] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disease caused by abnormally long CAG-repeats in the huntingtin gene that encode an expanded polyglutamine (polyQ) domain near the N-terminus of the huntingtin (htt) protein. Expanded polyQ domains are directly correlated to disease-related htt aggregation. Htt is found highly associated with a variety of cellular and subcellular membranes that are predominantly comprised of lipids. Since cholesterol homeostasis is altered in HD, we investigated how varying cholesterol content modifies the interactions between htt and lipid membranes. A combination of Langmuir trough monolayer techniques, vesicle permeability and binding assays, and in situ atomic force microscopy were used to directly monitor the interaction of a model, synthetic htt peptide and a full-length htt-exon1 recombinant protein with model membranes comprised of total brain lipid extract (TBLE) and varying amounts of exogenously added cholesterol. As the cholesterol content of the membrane increased, the extent of htt insertion decreased. Vesicles containing extra cholesterol were resistant to htt-induced permeabilization. Morphological and mechanical changes in the bilayer associated with exposure to htt were also drastically altered by the presence of cholesterol. Disrupted regions of pure TBLE bilayers were grainy in appearance and associated with a large number of globular aggregates. In contrast, morphological changes induced by htt in bilayers enriched in cholesterol were plateau-like with a smooth appearance. Collectively, these observations suggest that the presence and amount of cholesterol in lipid membranes play a critical role in htt binding and aggregation on lipid membranes.
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Affiliation(s)
- Xiang Gao
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Warren A Campbell
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Maxmore Chaibva
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Pranav Jain
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Ashley E Leslie
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Shelli L Frey
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States.,NanoSAFE, P.O. Box 6223, West Virginia University, Morgantown, West Virginia 26506, United States.,The Center for Neurosciences, West Virginia University, Morgantown, West Virginia 26505, United States
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44
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Berger TR, Montie HL, Jain P, Legleiter J, Merry DE. Identification of novel polyglutamine-expanded aggregation species in spinal and bulbar muscular atrophy. Brain Res 2015; 1628:254-264. [PMID: 26453288 DOI: 10.1016/j.brainres.2015.09.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/26/2015] [Accepted: 09/28/2015] [Indexed: 11/16/2022]
Abstract
Polyglutamine-repeat disorders are part of a larger family of neurodegenerative diseases characterized by protein misfolding and aggregation. In spinal and bulbar muscular atrophy (SBMA), polyglutamine expansion within the androgen receptor (AR) causes progressive debilitating muscular atrophy and lower motor neuron loss in males. Although soluble polyglutamine-expanded aggregation species are considered toxic intermediates in the aggregation process, relatively little is known about the spectrum of structures that are formed. Here we identify novel polyglutamine-expanded AR aggregates that are SDS-soluble and bind the toxicity-predicting antibody 3B5H10. Soluble, 3B5H10-reactive aggregation species exist in low-density conformations and are larger by atomic force microscopy, suggesting that they may be less compact than later-stage, insoluble aggregates. We demonstrate disease-relevance in vivo and draw correlations with toxicity in vitro. This article is part of a Special Issue entitled SI: Neuroprotection.
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Affiliation(s)
- Tamar R Berger
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, USA
| | - Heather L Montie
- Philadelphia College of Osteopathic Medicine, Department of Bio-Medical Sciences, Philadelphia, PA, USA
| | - Pranav Jain
- West Virginia University, Department of Chemistry, Morgantown, WV, USA
| | - Justin Legleiter
- West Virginia University, Department of Chemistry, Morgantown, WV, USA
| | - Diane E Merry
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, USA.
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45
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Is membrane homeostasis the missing link between inflammation and neurodegenerative diseases? Cell Mol Life Sci 2015; 72:4795-805. [PMID: 26403788 PMCID: PMC5005413 DOI: 10.1007/s00018-015-2038-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/16/2015] [Accepted: 09/03/2015] [Indexed: 12/14/2022]
Abstract
Systemic inflammation and infections are associated with neurodegenerative diseases. Unfortunately, the molecular bases of this link are still largely undiscovered. We, therefore, review how inflammatory processes can imbalance membrane homeostasis and theorize how this may have an effect on the aggregation behavior of the proteins implicated in such diseases. Specifically, we describe the processes that generate such imbalances at the molecular level, and try to understand how they affect protein folding and localization. Overall, current knowledge suggests that microglia pro-inflammatory mediators can generate membrane damage, which may have an impact in terms of triggering or accelerating disease manifestation.
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46
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Kegulian NC, Sankhagowit S, Apostolidou M, Jayasinghe SA, Malmstadt N, Butler PC, Langen R. Membrane Curvature-sensing and Curvature-inducing Activity of Islet Amyloid Polypeptide and Its Implications for Membrane Disruption. J Biol Chem 2015; 290:25782-93. [PMID: 26283787 DOI: 10.1074/jbc.m115.659797] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 11/06/2022] Open
Abstract
Islet amyloid polypeptide (IAPP) is a 37-amino acid amyloid protein intimately associated with pancreatic islet β-cell dysfunction and death in type II diabetes. In this study, we combine spectroscopic methods and microscopy to investigate α-helical IAPP-membrane interactions. Using light scattering and fluorescence microscopy, we observe that larger vesicles become smaller upon treatment with human or rat IAPP. Electron microscopy shows the formation of various highly curved structures such as tubules or smaller vesicles in a membrane-remodeling process, and spectrofluorometric detection of vesicle leakage shows disruption of membrane integrity. This effect is stronger for human IAPP than for the less toxic rat IAPP. From CD spectra in the presence of different-sized vesicles, we also uncover the membrane curvature-sensing ability of IAPP and find that it transitions from inducing to sensing membrane curvature when lipid negative charge is decreased. Our in vivo EM images of immunogold-labeled rat IAPP and human IAPP show both forms to localize to mitochondrial cristae, which contain not only locally curved membranes but also phosphatidylethanolamine and cardiolipin, lipids with high spontaneous negative curvature. Disruption of membrane integrity by induction of membrane curvature could apply more broadly to other amyloid proteins and be responsible for membrane damage observed in other amyloid diseases as well.
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Affiliation(s)
- Natalie C Kegulian
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Shalene Sankhagowit
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Melania Apostolidou
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Sajith A Jayasinghe
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Noah Malmstadt
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Peter C Butler
- the Larry Hillblom Islet Research Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Ralf Langen
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033,
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47
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De Genst E, Chirgadze DY, Klein FAC, Butler DC, Matak-Vinković D, Trottier Y, Huston JS, Messer A, Dobson CM. Structure of a single-chain Fv bound to the 17 N-terminal residues of huntingtin provides insights into pathogenic amyloid formation and suppression. J Mol Biol 2015; 427:2166-78. [PMID: 25861763 PMCID: PMC4451460 DOI: 10.1016/j.jmb.2015.03.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/17/2015] [Accepted: 03/30/2015] [Indexed: 10/25/2022]
Abstract
Huntington's disease is triggered by misfolding of fragments of mutant forms of the huntingtin protein (mHTT) with aberrant polyglutamine expansions. The C4 single-chain Fv antibody (scFv) binds to the first 17 residues of huntingtin [HTT(1-17)] and generates substantial protection against multiple phenotypic pathologies in situ and in vivo. We show in this paper that C4 scFv inhibits amyloid formation by exon1 fragments of huntingtin in vitro and elucidate the structural basis for this inhibition and protection by determining the crystal structure of the complex of C4 scFv and HTT(1-17). The peptide binds with residues 3-11 forming an amphipathic helix that makes contact with the antibody fragment in such a way that the hydrophobic face of this helix is shielded from the solvent. Residues 12-17 of the peptide are in an extended conformation and interact with the same region of another C4 scFv:HTT(1-17) complex in the asymmetric unit, resulting in a β-sheet interface within a dimeric C4 scFv:HTT(1-17) complex. The nature of this scFv-peptide complex was further explored in solution by high-resolution NMR and physicochemical analysis of species in solution. The results provide insights into the manner in which C4 scFv inhibits the aggregation of HTT, and hence into its therapeutic potential, and suggests a structural basis for the initial interactions that underlie the formation of disease-associated amyloid fibrils by HTT.
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Affiliation(s)
- Erwin De Genst
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Dimitri Y Chirgadze
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Fabrice A C Klein
- Translational Medicine and Neurogenetics Programme, Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch Cédex, France
| | - David C Butler
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA; Department of Biomedical Sciences, University at Albany, Albany, NY 12208, USA
| | - Dijana Matak-Vinković
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Yvon Trottier
- Translational Medicine and Neurogenetics Programme, Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch Cédex, France
| | - James S Huston
- James S. Huston, The Antibody Society, Newton, MA 02462, USA
| | - Anne Messer
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA; Department of Biomedical Sciences, University at Albany, Albany, NY 12208, USA
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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48
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Arndt JR, Brown RJ, Burke KA, Legleiter J, Valentine SJ. Lysine residues in the N-terminal huntingtin amphipathic α-helix play a key role in peptide aggregation. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:117-126. [PMID: 25601683 DOI: 10.1002/jms.3504] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/27/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
Huntington's disease is a genetic neurodegenerative disorder caused by an expansion in a polyglutamine domain near the N-terminus of the huntingtin (htt) protein that results in the formation of protein aggregates. Here, htt aggregate structure has been examined using hydrogen-deuterium exchange techniques coupled with tandem mass spectrometry. The focus of the study is on the 17-residue N-terminal flanking region of the peptide that has been shown to alter htt aggregation kinetics and morphology. A top-down sequencing strategy employing electron transfer dissociation is utilized to determine the location of accessible and protected hydrogens. In these experiments, peptides aggregate in a deuterium-rich solvent at neutral pH and are subsequently subjected to deuterium-hydrogen back-exchange followed by rapid quenching, disaggregation, and tandem mass spectrometry analysis. Electrospray ionization of the peptide solution produces the [M + 5H](5+) to [M + 10H](10+) charge states and reveals the presence of multiple peptide sequences differing by single glutamine residues. The [M + 7H](7+) to [M + 9](9+) charge states corresponding to the full peptide are used in the electron transfer dissociation analyses. Evidence for protected residues is observed in the 17-residue N-terminal tract and specifically points to lysine residues as potentially playing a significant role in htt aggregation.
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Affiliation(s)
- James R Arndt
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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Shamitko-Klingensmith N, Legleiter J. Investigation of temperature induced mechanical changes in supported bilayers by variants of tapping mode atomic force microscopy. SCANNING 2015; 37:23-35. [PMID: 25369473 DOI: 10.1002/sca.21175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/28/2014] [Accepted: 10/06/2014] [Indexed: 06/04/2023]
Abstract
Tapping mode atomic force microscopy (AFM) is an invaluable technique for examining topographical features of biological materials in solution, and there has been a growing interest in developing techniques to provide further compositional contrast and information concerning surface mechanical properties. Phase shifts, cantilever response at higher harmonic frequencies of the drive, and time-resolved tip/sample force reconstruction have all been shown to provide additional compositional contrast of surfaces, as compared to basic tapping mode AFM imaging. This study aimed to demonstrate the relative ability of these different imaging techniques to detect temperature induced changes in the elastic modulus of supported total brain lipid extract (TBLE) bilayer patches on mica. To aid in direct comparison between the different imaging techniques, all required data was obtained simultaneously while capturing traditional tapping mode AFM topography images. While all of the techniques were able to provide compositional contrast consistent with known temperature-induced changes in the bilayer patch, interpretation of the resulting contrast was not always straightforward. Phase imaging suffered from contrast inversion. Individual harmonics responded in a variety of ways to the temperature-induced changes in elastic modulus of the bilayer. The maximum tapping force (or peak force) associated with imaging the bilayer correctly reflected the changes in elastic modulus of the lipid bilayer. Importantly, as the required data can be obtained simultaneously, combining these different imaging techniques can lead to a more complete understanding of a sample's mechanical features.
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Affiliation(s)
- Nicole Shamitko-Klingensmith
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia; NanoSAFE, West Virginia University, Morgantown, West Virginia
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50
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Sahoo B, Singer D, Kodali R, Zuchner T, Wetzel R. Aggregation behavior of chemically synthesized, full-length huntingtin exon1. Biochemistry 2014; 53:3897-907. [PMID: 24921664 PMCID: PMC4075985 DOI: 10.1021/bi500300c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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Repeat
length disease thresholds vary among the 10 expanded polyglutamine
(polyQ) repeat diseases, from about 20 to about 50 glutamine residues.
The unique amino acid sequences flanking the polyQ segment are thought
to contribute to these repeat length thresholds. The specific portions
of the flanking sequences that modulate polyQ properties are not always
clear, however. This ambiguity may be important in Huntington’s
disease (HD), for example, where in vitro studies
of aggregation mechanisms have led to distinctly different mechanistic
models. Most in vitro studies of the aggregation
of the huntingtin (HTT) exon1 fragment implicated in the HD mechanism
have been conducted on inexact molecules that are imprecise either
on the N-terminus (recombinantly produced peptides) or on the C-terminus
(chemically synthesized peptides). In this paper, we investigate the
aggregation properties of chemically synthesized HTT exon1 peptides
that are full-length and complete, containing both normal and expanded
polyQ repeat lengths, and compare the results directly to previously
investigated molecules containing truncated C-termini. The results
on the full-length peptides are consistent with a two-step aggregation
mechanism originally developed based on studies of the C-terminally
truncated analogues. Thus, we observe relatively rapid formation of
spherical oligomers containing from 100 to 600 HTT exon1 molecules
and intermediate formation of short protofibril-like structures containing
from 500 to 2600 molecules. In contrast to this relatively rapid assembly,
mature HTT exon1 amyloid requires about one month to dissociate in vitro, which is similar to the time required for neuronal
HTT exon1 aggregates to disappear in vivo after HTT
production is discontinued.
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Affiliation(s)
- Bankanidhi Sahoo
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15260, United States
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