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Tanaka D, Yaguchi H, Yoshizaki K, Kudo A, Mori F, Nomura T, Pan J, Miki Y, Takahashi H, Hara T, Wakabayashi K, Yabe I. Behavioral and histological analyses of the mouse Bassoon p.P3882A mutation corresponding to the human BSN p.P3866A mutation. Front Neurosci 2024; 18:1414145. [PMID: 39130376 PMCID: PMC11310129 DOI: 10.3389/fnins.2024.1414145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 07/11/2024] [Indexed: 08/13/2024] Open
Abstract
Tauopathy is known to be a major pathognomonic finding in important neurodegenerative diseases such as progressive supranuclear palsy (PSP) and corticobasal degeneration. However, the mechanism by which tauopathy is triggered remains to be elucidated. We previously identified the point mutation c.11596C > G, p.Pro3866Ala in the Bassoon gene (BSN) in a Japanese family with PSP-like syndrome. We showed that mutated BSN may have been involved in its own insolubilization and tau accumulation. Furthermore, BSN mutations have also been related to various neurological diseases. In order to further investigate the pathophysiology of BSN mutation in detail, it is essential to study it in mouse models. We generated a mouse model with the mouse Bassoon p.P3882A mutation, which corresponds to the human BSN p.P3866A mutation, knock-in (KI) and we performed systematic behavioral and histological analyses. Behavioral analyses revealed impaired working memory in a Y-maze test at 3 months of age and decreased locomotor activity in the home cage at 3 and 12 months of age in KI mice compared to those in wild-type mice. Although no obvious structural abnormalities were observed at 3 months of age, immunohistochemical studies showed elevation of Bsn immunoreactivity in the hippocampus and neuronal loss without tau accumulation in the substantia nigra at 12 months of age in KI mice. Although our mice model did not show progressive cognitive dysfunction and locomotor disorder like PSP-like syndrome, dopaminergic neuronal loss was observed in the substantia nigra in 12-month-old KI mice. It is possible that BSN mutation may result in dopaminergic neuronal loss without locomotor symptoms due to the early disease stage. Thus, further clinical course can induce cognitive dysfunction and locomotor symptoms.
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Affiliation(s)
- Daiki Tanaka
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroaki Yaguchi
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kaichi Yoshizaki
- Department of Disease Model, Aichi Developmental Disability Center, Kasugai, Japan
- Integrated Analysis of Bioresource and Health Care, Future Medical Sciences, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Akihiko Kudo
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Fumiaki Mori
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Taichi Nomura
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Jing Pan
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuo Miki
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Taichi Hara
- Laboratory of Food and Life Science, Faculty of Human Sciences, Waseda University, Tokyo, Japan
| | - Koichi Wakabayashi
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ichiro Yabe
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Bavarsad MS, Grinberg LT. SV2A PET imaging in human neurodegenerative diseases. Front Aging Neurosci 2024; 16:1380561. [PMID: 38699560 PMCID: PMC11064927 DOI: 10.3389/fnagi.2024.1380561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 05/05/2024] Open
Abstract
This manuscript presents a thorough review of synaptic vesicle glycoprotein 2A (SV2A) as a biomarker for synaptic integrity using Positron Emission Tomography (PET) in neurodegenerative diseases. Synaptic pathology, characterized by synaptic loss, has been linked to various brain diseases. Therefore, there is a need for a minimally invasive approach to measuring synaptic density in living human patients. Several radiotracers targeting synaptic vesicle protein 2A (SV2A) have been created and effectively adapted for use in human subjects through PET scans. SV2A is an integral glycoprotein found in the membranes of synaptic vesicles in all synaptic terminals and is widely distributed throughout the brain. The review delves into the development of SV2A-specific PET radiotracers, highlighting their advancements and limitations in neurodegenerative diseases. Among these tracers, 11C-UCB-J is the most used so far. We summarize and discuss an increasing body of research that compares measurements of synaptic density using SV2A PET with other established indicators of neurodegenerative diseases, including cognitive performance and radiological findings, thus providing a comprehensive analysis of SV2A's effectiveness and reliability as a diagnostic tool in contrast to traditional markers. Although the literature overall suggests the promise of SV2A as a diagnostic and therapeutic monitoring tool, uncertainties persist regarding the superiority of SV2A as a biomarker compared to other available markers. The review also underscores the paucity of studies characterizing SV2A distribution and loss in human brain tissue from patients with neurodegenerative diseases, emphasizing the need to generate quantitative neuropathological maps of SV2A density in cases with neurodegenerative diseases to fully harness the potential of SV2A PET imaging in clinical settings. We conclude by outlining future research directions, stressing the importance of integrating SV2A PET imaging with other biomarkers and clinical assessments and the need for longitudinal studies to track SV2A changes throughout neurodegenerative disease progression, which could lead to breakthroughs in early diagnosis and the evaluation of new treatments.
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Affiliation(s)
| | - Lea T. Grinberg
- Memory and Aging Center, Weill Institute for Neurosciences, University of California, San Francisco (UCSF), San Francisco, CA, United States
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Dinamarca MC, Colombo L, Tousiaki NE, Müller M, Pecho-Vrieseling E. Synaptic and functional alterations in the development of mutant huntingtin expressing hiPSC‐derived neurons. Front Mol Biosci 2022; 9:916019. [PMID: 35928225 PMCID: PMC9343803 DOI: 10.3389/fmolb.2022.916019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
Huntington’s disease (HD) is a monogenic disease that results in a combination of motor, psychiatric, and cognitive symptoms. It is caused by a CAG trinucleotide repeat expansion in the exon 1 of the huntingtin (HTT) gene, which results in the production of a mutant HTT protein (mHTT) with an extended polyglutamine tract (PolyQ). Severe motor symptoms are a hallmark of HD and typically appear during middle age; however, mild cognitive and personality changes often occur already during early adolescence. Wild-type HTT is a regulator of synaptic functions and plays a role in axon guidance, neurotransmitter release, and synaptic vesicle trafficking. These functions are important for proper synapse assembly during neuronal network formation. In the present study, we assessed the effect of mHTT exon1 isoform on the synaptic and functional maturation of human induced pluripotent stem cell (hiPSC)-derived neurons. We used a relatively fast-maturing hiPSC line carrying a doxycycline-inducible pro-neuronal transcription factor, (iNGN2), and generated a double transgenic line by introducing only the exon 1 of HTT, which carries the mutant CAG (mHTTEx1). The characterization of our cell lines revealed that the presence of mHTTEx1 in hiPSC-derived neurons alters the synaptic protein appearance, decreases synaptic contacts, and causes a delay in the development of a mature neuronal activity pattern, recapitulating some of the developmental alterations observed in HD models, nonetheless in a shorted time window. Our data support the notion that HD has a neurodevelopmental component and is not solely a degenerative disease.
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Affiliation(s)
| | - Laura Colombo
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Matthias Müller
- Novartis Institute for Biomedical Research, Basel, Switzerland
| | - Eline Pecho-Vrieseling
- Department of Biomedicine, University of Basel, Basel, Switzerland
- *Correspondence: Eline Pecho-Vrieseling,
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Mees I, Tran H, Roberts A, Lago L, Li S, Roberts BR, Hannan AJ, Renoir T. Quantitative Phosphoproteomics Reveals Extensive Protein Phosphorylation Dysregulation in the Cerebral Cortex of Huntington's Disease Mice Prior to Onset of Symptoms. Mol Neurobiol 2022; 59:2456-2471. [PMID: 35083661 DOI: 10.1007/s12035-021-02698-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 12/13/2021] [Indexed: 11/29/2022]
Abstract
Protein phosphorylation plays a role in many important cellular functions such as cellular plasticity, gene expression, and intracellular trafficking. All of these are dysregulated in Huntington's disease (HD), a devastating neurodegenerative disorder caused by an expanded CAG repeat in exon 1 of the huntingtin gene. However, no studies have yet found protein phosphorylation differences in preclinical HD mouse models. Our current study investigated changes occurring in the cortical phosphoproteome of 8-week-old (prior to motor deficits) and 20-week-old (fully symptomatic) R6/1 transgenic HD mice. When comparing 8-week-old HD mice with their wild-type (WT) littermates, we found 660 peptides differentially phosphorylated, which were mapped to 227 phosphoproteins. These proteins were mainly involved in synaptogenesis, cytoskeleton organization, axon development, and nervous system development. Tau protein, found hyperphosphorylated at multiple sites in early symptomatic HD mice, also appeared as a main upstream regulator for the changes observed. Surprisingly, we found fewer changes in the phosphorylation profile of HD mice at the fully symptomatic stage, with 29 peptides differentially phosphorylated compared to WT mice, mapped to 25 phosphoproteins. These proteins were involved in cAMP signaling, dendrite development, and microtubule binding. Furthermore, huntingtin protein appeared as an upstream regulator for the changes observed at the fully symptomatic stage, suggesting impacts on kinases and phosphatases that extend beyond the mutated polyglutamine tract. In summary, our findings show that the most extensive changes in the phosphorylation machinery appear at an early presymptomatic stage in HD pathogenesis and might constitute a new target for the development of treatments.
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Affiliation(s)
- Isaline Mees
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Harvey Tran
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Anne Roberts
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Larissa Lago
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Shanshan Li
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Blaine R Roberts
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Anthony J Hannan
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia.,Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Thibault Renoir
- Melbourne Brain Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3010, Australia. .,Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia.
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Iuliano M, Seeley C, Sapp E, Jones EL, Martin C, Li X, DiFiglia M, Kegel-Gleason KB. Disposition of Proteins and Lipids in Synaptic Membrane Compartments Is Altered in Q175/Q7 Huntington's Disease Mouse Striatum. Front Synaptic Neurosci 2021; 13:618391. [PMID: 33815086 PMCID: PMC8013775 DOI: 10.3389/fnsyn.2021.618391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Dysfunction at synapses is thought to be an early change contributing to cognitive, psychiatric and motor disturbances in Huntington's disease (HD). In neurons, mutant Huntingtin collects in aggregates and distributes to the same sites as wild-type Huntingtin including on membranes and in synapses. In this study, we investigated the biochemical integrity of synapses in HD mouse striatum. We performed subcellular fractionation of striatal tissue from 2 and 6-month old knock-in Q175/Q7 HD and Q7/Q7 mice. Compared to striata of Q7/Q7 mice, proteins including GLUT3, Na+/K+ ATPase, NMDAR 2b, PSD95, and VGLUT1 had altered distribution in Q175/Q7 HD striata of 6-month old mice but not 2-month old mice. These proteins are found on plasma membranes and pre- and postsynaptic membranes supporting hypotheses that functional changes at synapses contribute to cognitive and behavioral symptoms of HD. Lipidomic analysis of mouse fractions indicated that compared to those of wild-type, fractions 1 and 2 of 6 months Q175/Q7 HD had altered levels of two species of PIP2, a phospholipid involved in synaptic signaling, increased levels of cholesterol ester and decreased cardiolipin species. At 2 months, increased levels of species of acylcarnitine, phosphatidic acid and sphingomyelin were measured. EM analysis showed that the contents of fractions 1 and 2 of Q7/Q7 and Q175/Q7 HD striata had a mix of isolated synaptic vesicles, vesicle filled axon terminals singly or in clusters, and ER and endosome-like membranes. However, those of Q175/Q7 striata contained significantly fewer and larger clumps of particles compared to those of Q7/Q7. Human HD postmortem putamen showed differences from control putamen in subcellular distribution of two proteins (Calnexin and GLUT3). Our biochemical, lipidomic and EM analysis show that the presence of the HD mutation conferred age dependent disruption of localization of synaptic proteins and lipids important for synaptic function. Our data demonstrate concrete biochemical changes suggesting altered integrity of synaptic compartments in HD mice that may mirror changes in HD patients and presage cognitive and psychiatric changes that occur in premanifest HD.
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