1
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Sun B, Ding T, Zhou W, Porter TS, Lew MD. Single-Molecule Orientation Imaging Reveals the Nano-Architecture of Amyloid Fibrils Undergoing Growth and Decay. NANO LETTERS 2024. [PMID: 38828968 DOI: 10.1021/acs.nanolett.4c01263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Amyloid-beta (Aβ42) aggregates are characteristic Alzheimer's disease signatures, but probing how their nanoscale architectures influence their growth and decay remains challenging using current technologies. Here, we apply time-lapse single-molecule orientation-localization microscopy (SMOLM) to measure the orientations and rotational "wobble" of Nile blue (NB) molecules transiently binding to Aβ42 fibrils. We correlate fibril architectures measured by SMOLM with their growth and decay over the course of 5 to 20 min visualized by single-molecule localization microscopy (SMLM). We discover that stable Aβ42 fibrils tend to be well-ordered and signified by well-aligned NB orientations and small wobble. SMOLM also shows that increasing order and disorder are signatures of growing and decaying fibrils, respectively. We also observe SMLM-invisible fibril remodeling, including steady growth and decay patterns that conserve β-sheet organization. SMOLM reveals that increased fibril architectural heterogeneity is correlated with dynamic remodeling and that large-scale fibril remodeling tends to originate from strongly heterogeneous local regions.
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Affiliation(s)
- Brian Sun
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Weiyan Zhou
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tara S Porter
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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2
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Chen H, Yan G, Wen MH, Brooks KN, Zhang Y, Huang PS, Chen TY. Advancements and Practical Considerations for Biophysical Research: Navigating the Challenges and Future of Super-resolution Microscopy. CHEMICAL & BIOMEDICAL IMAGING 2024; 2:331-344. [PMID: 38817319 PMCID: PMC11134610 DOI: 10.1021/cbmi.4c00019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 04/06/2024] [Accepted: 04/10/2024] [Indexed: 06/01/2024]
Abstract
The introduction of super-resolution microscopy (SRM) has significantly advanced our understanding of cellular and molecular dynamics, offering a detailed view previously beyond our reach. Implementing SRM in biophysical research, however, presents numerous challenges. This review addresses the crucial aspects of utilizing SRM effectively, from selecting appropriate fluorophores and preparing samples to analyzing complex data sets. We explore recent technological advancements and methodological improvements that enhance the capabilities of SRM. Emphasizing the integration of SRM with other analytical methods, we aim to overcome inherent limitations and expand the scope of biological insights achievable. By providing a comprehensive guide for choosing the most suitable SRM methods based on specific research objectives, we aim to empower researchers to explore complex biological processes with enhanced precision and clarity, thereby advancing the frontiers of biophysical research.
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Affiliation(s)
- Huanhuan Chen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Guangjie Yan
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Meng-Hsuan Wen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Kameron N. Brooks
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Yuteng Zhang
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Pei-San Huang
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Tai-Yen Chen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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3
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Sun B, Ding T, Zhou W, Porter TS, Lew MD. Single-Molecule Orientation Imaging Reveals the Nano-Architecture of Amyloid Fibrils Undergoing Growth and Decay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.24.586510. [PMID: 38585908 PMCID: PMC10996564 DOI: 10.1101/2024.03.24.586510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Amyloid-beta ( A β 42 ) aggregates are characteristic signatures of Alzheimer's disease, but probing how their nanoscale architectures influence their growth and decay remains challenging using current technologies. Here, we apply time-lapse single-molecule orientation-localization microscopy (SMOLM) to measure the orientations and rotational "wobble" of Nile blue (NB) molecules transiently binding to A β 42 fibrils. We quantify correlations between fibril architectures, measured by SMOLM, and their growth and decay visualized by single-molecule localization microscopy (SMLM). We discover that stable A β 42 fibrils tend to be well-ordered, signified by well-aligned NB orientations and small wobble. SMOLM also shows that increasing order and disorder are signatures of growing and decaying A β 42 fibrils, respectively. We also observe SMLM-invisible fibril remodeling, including steady growth and decay patterns that conserve β -sheet organization. SMOLM reveals that increased heterogeneity in fibril architectures is correlated with more dynamic remodeling and that large-scale fibril remodeling tends to originate from local regions that exhibit strong heterogeneity.
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Affiliation(s)
- Brian Sun
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Weiyan Zhou
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Tara S. Porter
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Matthew D. Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
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4
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Dunot J, Ribera A, Pousinha PA, Marie H. Spatiotemporal insights of APP function. Curr Opin Neurobiol 2023; 82:102754. [PMID: 37542943 DOI: 10.1016/j.conb.2023.102754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/29/2023] [Accepted: 07/07/2023] [Indexed: 08/07/2023]
Abstract
The amyloid-β precursor protein (APP) is a ubiquitous protein with a strong genetic link to Alzheimer's disease. Although the protein was identified more than forty years ago, its physiological function is still unclear. In recent years, advances in technology have allowed researchers to tackle APP functions in greater depth. In this review, we discuss the latest research pertaining to APP functions from development to aging. We also address the different roles that APP could play in specific types of cells of the central and peripheral nervous system and in other organs of the body. We argue that, until we fully identify the functions of APP in space and time, we will be missing important pieces of the puzzle to solve its pathological implication in Alzheimer's disease and beyond.
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Affiliation(s)
- Jade Dunot
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France. https://twitter.com/DunotJade
| | - Aurore Ribera
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France. https://twitter.com/aurore_et_al_
| | - Paula A Pousinha
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France.
| | - Hélène Marie
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, 06560, Valbonne, France.
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5
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Belapurkar V, Mahadeva Swamy HS, Singh N, Kedia S, Setty SRG, Jose M, Nair D. Real-time heterogeneity of supramolecular assembly of amyloid precursor protein is modulated by an endocytic risk factor PICALM. Cell Mol Life Sci 2023; 80:295. [PMID: 37726569 PMCID: PMC11072284 DOI: 10.1007/s00018-023-04939-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/10/2023] [Accepted: 07/25/2023] [Indexed: 09/21/2023]
Abstract
Recently, the localization of amyloid precursor protein (APP) into reversible nanoscale supramolecular assembly or "nanodomains" has been highlighted as crucial towards understanding the onset of the molecular pathology of Alzheimer's disease (AD). Surface expression of APP is regulated by proteins interacting with it, controlling its retention and lateral trafficking on the synaptic membrane. Here, we evaluated the involvement of a key risk factor for AD, PICALM, as a critical regulator of nanoscale dynamics of APP. Although it was enriched in the postsynaptic density, PICALM was also localized to the presynaptic active zone and the endocytic zone. PICALM colocalized with APP and formed nanodomains with distinct morphological properties in different subsynaptic regions. Next, we evaluated if this localization to subsynaptic compartments was regulated by the C-terminal sequences of APP, namely, the "Y682ENPTY687" domain. Towards this, we found that deletion of C-terminal regions of APP with partial or complete deletion of Y682ENPTY687, namely, APP-Δ9 and APP-Δ14, affected the lateral diffusion and nanoscale segregation of APP. Lateral diffusion of APP mutant APP-Δ14 sequence mimicked that of a detrimental Swedish mutant of APP, namely, APP-SWE, while APP-Δ9 diffused similar to wild-type APP. Interestingly, elevated expression of PICALM differentially altered the lateral diffusion of the APP C-terminal deletion mutants. These observations confirm that the C-terminal sequence of APP regulates its lateral diffusion and the formation of reversible nanoscale domains. Thus, when combined with autosomal dominant mutations, it generates distinct molecular patterns leading to onset of Alzheimer's disease (AD).
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Affiliation(s)
- Vivek Belapurkar
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Interdisciplinary Institute for Neuroscience CNRS UMR5297, University of Bordeaux, Bordeaux, France
| | - H S Mahadeva Swamy
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Tata Institute for Genetics and Society, Bengaluru, India
| | - Nivedita Singh
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
| | - Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Mini Jose
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India.
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6
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Cai W, Li L, Sang S, Pan X, Zhong C. Physiological Roles of β-amyloid in Regulating Synaptic Function: Implications for AD Pathophysiology. Neurosci Bull 2023; 39:1289-1308. [PMID: 36443453 PMCID: PMC10387033 DOI: 10.1007/s12264-022-00985-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
The physiological functions of endogenous amyloid-β (Aβ), which plays important role in the pathology of Alzheimer's disease (AD), have not been paid enough attention. Here, we review the multiple physiological effects of Aβ, particularly in regulating synaptic transmission, and the possible mechanisms, in order to decipher the real characters of Aβ under both physiological and pathological conditions. Some worthy studies have shown that the deprivation of endogenous Aβ gives rise to synaptic dysfunction and cognitive deficiency, while the moderate elevation of this peptide enhances long term potentiation and leads to neuronal hyperexcitability. In this review, we provide a new view for understanding the role of Aβ in AD pathophysiology from the perspective of physiological meaning.
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Affiliation(s)
- Wenwen Cai
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Linxi Li
- Basic Medical College, Nanchang University, Nanchang, 330031, China
| | - Shaoming Sang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xiaoli Pan
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Chunjiu Zhong
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science & Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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7
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Mangalwedhekar R, Singh N, Thakur CS, Seelamantula CS, Jose M, Nair D. Achieving nanoscale precision using neuromorphic localization microscopy. NATURE NANOTECHNOLOGY 2023; 18:380-389. [PMID: 36690737 DOI: 10.1038/s41565-022-01291-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/09/2022] [Indexed: 06/17/2023]
Abstract
Neuromorphic cameras are a new class of dynamic-vision-inspired sensors that encode the rate of change of intensity as events. They can asynchronously record intensity changes as spikes, independent of the other pixels in the receptive field, resulting in sparse measurements. This recording of such sparse events makes them ideal for imaging dynamic processes, such as the stochastic emission of isolated single molecules. Here we show the application of neuromorphic detection to localize nanoscale fluorescent objects below the diffraction limit, with a precision below 20 nm. We demonstrate a combination of neuromorphic detection with segmentation and deep learning approaches to localize and track fluorescent particles below 50 nm with millisecond temporal resolution. Furthermore, we show that combining information from events resulting from the rate of change of intensities improves the classical limit of centroid estimation of single fluorescent objects by nearly a factor of two. Additionally, we validate that using post-processed data from the neuromorphic detector at defined windows of temporal integration allows a better evaluation of the fractalized diffusion of single particle trajectories. Our observations and analysis is useful for event sensing by nonlinear neuromorphic devices to ameliorate real-time particle localization approaches at the nanoscale.
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Affiliation(s)
| | - Nivedita Singh
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Chetan Singh Thakur
- Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore, India
| | | | - Mini Jose
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India.
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8
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Fyn nanoclustering requires switching to an open conformation and is enhanced by FTLD-Tau biomolecular condensates. Mol Psychiatry 2023; 28:946-962. [PMID: 36258016 PMCID: PMC9908554 DOI: 10.1038/s41380-022-01825-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/19/2022] [Accepted: 09/27/2022] [Indexed: 11/08/2022]
Abstract
Fyn is a Src kinase that controls critical signalling cascades and has been implicated in learning and memory. Postsynaptic enrichment of Fyn underpins synaptotoxicity in dementias such as Alzheimer's disease and frontotemporal lobar degeneration with Tau pathology (FTLD-Tau). The FLTD P301L mutant Tau is associated with a higher propensity to undergo liquid-liquid phase separation (LLPS) and form biomolecular condensates. Expression of P301L mutant Tau promotes aberrant trapping of Fyn in nanoclusters within hippocampal dendrites by an unknown mechanism. Here, we used single-particle tracking photoactivated localisation microscopy to demonstrate that the opening of Fyn into its primed conformation promotes its nanoclustering in dendrites leading to increased Fyn/ERK/S6 downstream signalling. Preventing the auto-inhibitory closed conformation of Fyn through phospho-inhibition or through perturbation of its SH3 domain increased Fyn's nanoscale trapping, whereas inhibition of the catalytic domain had no impact. By combining pharmacological and genetic approaches, we demonstrate that P301L Tau enhanced both Fyn nanoclustering and Fyn/ERK/S6 signalling via its ability to form biomolecular condensates. Together, our findings demonstrate that Fyn alternates between a closed and an open conformation, the latter being enzymatically active and clustered. Furthermore, pathogenic immobilisation of Fyn relies on the ability of P301L Tau to form biomolecular condensates, thus highlighting the critical importance of LLPS in controlling nanoclustering and downstream intracellular signalling events.
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9
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Haukedal H, Corsi GI, Gadekar VP, Doncheva NT, Kedia S, de Haan N, Chandrasekaran A, Jensen P, Schiønning P, Vallin S, Marlet FR, Poon A, Pires C, Agha FK, Wandall HH, Cirera S, Simonsen AH, Nielsen TT, Nielsen JE, Hyttel P, Muddashetty R, Aldana BI, Gorodkin J, Nair D, Meyer M, Larsen MR, Freude K. Golgi fragmentation - One of the earliest organelle phenotypes in Alzheimer's disease neurons. Front Neurosci 2023; 17:1120086. [PMID: 36875643 PMCID: PMC9978754 DOI: 10.3389/fnins.2023.1120086] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/30/2023] [Indexed: 02/18/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, with no current cure. Consequently, alternative approaches focusing on early pathological events in specific neuronal populations, besides targeting the well-studied amyloid beta (Aβ) accumulations and Tau tangles, are needed. In this study, we have investigated disease phenotypes specific to glutamatergic forebrain neurons and mapped the timeline of their occurrence, by implementing familial and sporadic human induced pluripotent stem cell models as well as the 5xFAD mouse model. We recapitulated characteristic late AD phenotypes, such as increased Aβ secretion and Tau hyperphosphorylation, as well as previously well documented mitochondrial and synaptic deficits. Intriguingly, we identified Golgi fragmentation as one of the earliest AD phenotypes, indicating potential impairments in protein processing and post-translational modifications. Computational analysis of RNA sequencing data revealed differentially expressed genes involved in glycosylation and glycan patterns, whilst total glycan profiling revealed minor glycosylation differences. This indicates general robustness of glycosylation besides the observed fragmented morphology. Importantly, we identified that genetic variants in Sortilin-related receptor 1 (SORL1) associated with AD could aggravate the Golgi fragmentation and subsequent glycosylation changes. In summary, we identified Golgi fragmentation as one of the earliest disease phenotypes in AD neurons in various in vivo and in vitro complementary disease models, which can be exacerbated via additional risk variants in SORL1.
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Affiliation(s)
- Henriette Haukedal
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Giulia I Corsi
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark
| | - Veerendra P Gadekar
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark
| | - Nadezhda T Doncheva
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark.,Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
| | - Noortje de Haan
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Abinaya Chandrasekaran
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Pia Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Pernille Schiønning
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Sarah Vallin
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Frederik Ravnkilde Marlet
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Poon
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Carlota Pires
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Fawzi Khoder Agha
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans H Wandall
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Susanna Cirera
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Anja Hviid Simonsen
- Danish Dementia Research Centre, Department of Neurology, Neuroscience Centre, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Troels Tolstrup Nielsen
- Danish Dementia Research Centre, Department of Neurology, Neuroscience Centre, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Jørgen Erik Nielsen
- Danish Dementia Research Centre, Department of Neurology, Neuroscience Centre, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Poul Hyttel
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Ravi Muddashetty
- Institute for Stem Cell Science and Regenerative Medicine, Bengaluru, India
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jan Gorodkin
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
| | - Morten Meyer
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Martin Røssel Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Kristine Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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10
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Rajeev P, Singh N, Kechkar A, Butler C, Ramanan N, Sibarita JB, Jose M, Nair D. Nanoscale regulation of Ca2+ dependent phase transitions and real-time dynamics of SAP97/hDLG. Nat Commun 2022; 13:4236. [PMID: 35869063 PMCID: PMC9307800 DOI: 10.1038/s41467-022-31912-1] [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: 09/17/2021] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Synapse associated protein-97/Human Disk Large (SAP97/hDLG) is a conserved, alternatively spliced, modular, scaffolding protein critical in regulating the molecular organization of cell-cell junctions in vertebrates. We confirm that the molecular determinants of first order phase transition of SAP97/hDLG is controlled by morpho-functional changes in its nanoscale organization. Furthermore, the nanoscale molecular signatures of these signalling islands and phase transitions are altered in response to changes in cytosolic Ca2+. Additionally, exchange kinetics of alternatively spliced isoforms of the intrinsically disordered region in SAP97/hDLG C-terminus shows differential sensitivities to Ca2+ bound Calmodulin, affirming that the molecular signatures of local phase transitions of SAP97/hDLG depends on their nanoscale heterogeneity and compositionality of isoforms. SAP97/hDLG is a ubiquitous, alternatively spliced, and conserved modular scaffolding protein involved in the organization cell junctions and excitatory synapses. Here, authors confirm that SAP97/hDLG condenses in to nanosized molecular domains in both heterologous cells and hippocampal pyramidal neurons. Authors demonstrate that in vivo and in vitro condensation, molecular signatures of nanoscale condensates and exchange kinetics of SAP97/hDLG is modulated by the local availability of alternatively spliced isoforms. Additionally, SAP97/hDLG isoforms exhibits a differential sensitivity to Ca2+ bound Calmodulin, resulting in altered properties of nanocondensates and their real-time regulation
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11
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Jose M, Sivanand A, Channakeshava C. Membrane Cholesterol Is a Critical Determinant for Hippocampal Neuronal Polarity. Front Mol Neurosci 2021; 14:746211. [PMID: 34744625 PMCID: PMC8566733 DOI: 10.3389/fnmol.2021.746211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
Maintaining a normal cholesterol balance is crucial for the functioning of a healthy brain. Dysregulation in cholesterol metabolism and homeostasis in the brain have been correlated to various neurological disorders. The majority of previous studies in primary cultures focus on the role of cholesterol balance in neuronal development after polarity has been established. Here we have investigated how transient alteration of membrane lipids, specifically cholesterol, affects neuronal development and polarity in developing hippocampal neurons prior to polarity establishment, soon after initiation of neurite outgrowth. We observed that temporary cholesterol perturbation affects axonal and dendritic development differentially in an opposing manner. Transient membrane cholesterol deficiency increased neuronal population with a single neurite, simultaneously generating a second population of neurons with supernumerary axons. Brief replenishment of cholesterol immediately after cholesterol sequestering rescued neuronal development defects and restored polarity. The results showed a small window of cholesterol concentration to be complementing neurite outgrowth, polarity reestablishment, and in determining the normal neuronal morphology, emphasizing the critical role of precise membrane lipid balance in defining the neuronal architecture. Membrane cholesterol enhancement modified neurite outgrowth but did not significantly alter polarity. Cholesterol sequestering at later stages of development has shown to enhance neurite outgrowth, whereas distinct effects for neurite development and polarity were observed at early developmental stages, signifying the relevance of precise membrane cholesterol balance in altering neuronal physiology. Our results confirm cholesterol to be a key determinant for axo-dendritic specification and neuronal architecture and emphasize the possibility to reverse neuronal developmental defects caused by cholesterol deficiency by modulating membrane cholesterol during the early developmental stages.
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Affiliation(s)
- Mini Jose
- Centre for Neuroscience, Indian institute of Science, Bangalore, India
| | - Aiswarya Sivanand
- Centre for Neuroscience, Indian institute of Science, Bangalore, India
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12
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Super-resolution microscopy: a closer look at synaptic dysfunction in Alzheimer disease. Nat Rev Neurosci 2021; 22:723-740. [PMID: 34725519 DOI: 10.1038/s41583-021-00531-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 11/08/2022]
Abstract
The synapse has emerged as a critical neuronal structure in the degenerative process of Alzheimer disease (AD), in which the pathogenic signals of two key players - amyloid-β (Aβ) and tau - converge, thereby causing synaptic dysfunction and cognitive deficits. The synapse presents a dynamic, confined microenvironment in which to explore how key molecules travel, localize, interact and assume different levels of organizational complexity, thereby affecting neuronal function. However, owing to their small size and the diffraction-limited resolution of conventional light microscopic approaches, investigating synaptic structure and dynamics has been challenging. Super-resolution microscopy (SRM) techniques have overcome the resolution barrier and are revolutionizing our quantitative understanding of biological systems in unprecedented spatio-temporal detail. Here we review critical new insights provided by SRM into the molecular architecture and dynamic organization of the synapse and, in particular, the interactions between Aβ and tau in this compartment. We further highlight how SRM can transform our understanding of the molecular pathological mechanisms that underlie AD. The application of SRM for understanding the roles of synapses in AD pathology will provide a stepping stone towards a broader understanding of dysfunction in other subcellular compartments and at cellular and circuit levels in this disease.
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Kedia S, Mandal K, Netrakanti PR, Jose M, Sisodia SS, Nair D. Nanoscale organization of Nicastrin, the substrate receptor of the γ-secretase complex, as independent molecular domains. Mol Brain 2021; 14:158. [PMID: 34645511 PMCID: PMC8515736 DOI: 10.1186/s13041-021-00855-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/09/2021] [Indexed: 11/10/2022] Open
Abstract
Alterations in the canonical processing of Amyloid Precursor Protein generate proteoforms that contribute to the onset of Alzheimer’s Disease. Modified composition of γ-secretase or mutations in its subunits has been directly linked to altered generation of Amyloid beta. Despite biochemical evidence about the role of γ-secretase in the generation of APP, the molecular origin of how spatial heterogeneity in the generation of proteoforms arises is not well understood. Here, we evaluated the localization of Nicastrin, a γ-secretase subunit, at nanometer sized functional zones of the synapse. With the help of super resolution microscopy, we confirm that Nicastrin is organized into nanodomains of high molecular density within an excitatory synapse. A similar nanoorganization was also observed for APP and the catalytic subunit of γ-secretase, Presenilin 1, that were discretely associated with Nicastrin nanodomains. Though Nicastrin is a functional subunit of γ-secretase, the Nicastrin and Presenilin1 nanodomains were either colocalized or localized independent of each other. The Nicastrin and Presenilin domains highlight a potential independent regulation of these molecules different from their canonical secretase function. The collisions between secretases and substrate molecules decide the probability and rate of product formation for transmembrane proteolysis. Our observations of secretase nanodomains indicate a spatial difference in the confinement of substrate and secretases, affecting the local probability of product formation by increasing their molecular availability, resulting in differential generation of proteoforms even within single synapses.
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Affiliation(s)
- Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, 560012, Bangalore, India
| | - Kousik Mandal
- Centre for Neuroscience, Indian Institute of Science, 560012, Bangalore, India
| | | | - Mini Jose
- Centre for Neuroscience, Indian Institute of Science, 560012, Bangalore, India
| | - Sangram S Sisodia
- Centre for Molecular Neurobiology, Department of Neurobiology, The University of Chicago, 60637, Chicago, IL, USA
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, 560012, Bangalore, India.
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Lankipalli S, H S MS, Selvam D, Samanta D, Nair D, Ramagopal UA. Cryptic association of B7-2 molecules and its implication for clustering. Protein Sci 2021; 30:1958-1973. [PMID: 34191384 PMCID: PMC8376414 DOI: 10.1002/pro.4151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
T-cell co-stimulation through CD28/CTLA4:B7-1/B7-2 axis is one of the extensively studied pathways that resulted in the discovery of several FDA-approved drugs for autoimmunity and cancer. However, many aspects of the signaling mechanism remain elusive, including oligomeric association and clustering of B7-2 on the cell surface. Here, we describe the structure of the IgV domain of B7-2 and its cryptic association into 1D arrays that appear to represent the pre-signaling state of B7-2 on the cell membrane. Super-resolution microscopy experiments on heterologous cells expressing B7-2 and B7-1 suggest, B7-2 form relatively elongated and larger clusters compared to B7-1. The sequence and structural comparison of other B7 family members, B7-1:CTLA4 and B7-2:CTLA-4 complex structures, support our view that the observed B7-2 1D zipper array is physiologically important. This observed 1D zipper-like array also provides an explanation for its clustering, and upright orientation on the cell surface, and avoidance of spurious signaling.
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Affiliation(s)
- Swetha Lankipalli
- Biological Sciences DivisionPoornaprajna Institute of Scientific Research (PPISR)BengaluruIndia
- Manipal Academy of Higher EducationManipalKarnatakaIndia
| | | | - Deepak Selvam
- Jawaharlal Nehru Center for Advance Scientific ResearchBengaluruKarnatakaIndia
- National Institute for Research in TuberculosisChennaiIndia
| | - Dibyendu Samanta
- School of Bioscience, Sir J. C. Bose Laboratory ComplexIndian Institute of Technology KharagpurKharagpurIndia
| | - Deepak Nair
- Centre for NeuroscienceIndian Institute of ScienceBangaloreIndia
| | - Udupi A. Ramagopal
- Biological Sciences DivisionPoornaprajna Institute of Scientific Research (PPISR)BengaluruIndia
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15
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Yu Y, Gao Y, Winblad B, Tjernberg LO, Schedin-Weiss S. A Super-Resolved View of the Alzheimer's Disease-Related Amyloidogenic Pathway in Hippocampal Neurons. J Alzheimers Dis 2021; 83:833-852. [PMID: 34366358 PMCID: PMC8543249 DOI: 10.3233/jad-215008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Processing of the amyloid-β protein precursor (AβPP) is neurophysiologically important due to the resulting fragments that regulate synapse biology, as well as potentially harmful due to generation of the 42 amino acid long amyloid β-peptide (Aβ42), which is a key player in Alzheimer's disease. OBJECTIVE Our aim was to clarify the subcellular locations of the fragments involved in the amyloidogenic pathway in primary neurons with a focus on Aβ42 and its immediate substrate AβPP C-terminal fragment (APP-CTF). To overcome the difficulties of resolving these compartments due to their small size, we used super-resolution microscopy. METHODS Mouse primary hippocampal neurons were immunolabelled and imaged by stimulated emission depletion (STED) microscopy, including three-dimensional three-channel imaging, and quantitative image analyses. RESULTS The first (β-secretase) and second (γ-secretase) cleavages of AβPP were localized to functionally and distally distinct compartments. The β-secretase cleavage was observed in early endosomes in soma, where we were able to show that the liberated N- and C-terminal fragments were sorted into distinct vesicles budding from the early endosomes. Lack of colocalization of Aβ42 and APP-CTF in soma suggested that γ-secretase cleavage occurs in neurites. Indeed, APP-CTF was, in line with Aβ42 in our previous study, enriched in the presynapse but absent from the postsynapse. In contrast, full-length AβPP was not detected in either the pre- or the postsynaptic side of the synapse. Furthermore, we observed that endogenously produced and endocytosed Aβ42 were localized in different compartments. CONCLUSION These findings provide critical super-resolved insight into amyloidogenic AβPP processing in primary neurons.
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Affiliation(s)
- Yang Yu
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Yang Gao
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Bengt Winblad
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden.,Theme Inflammation and Aging, Karolinska University Hospital, Huddinge, Sweden
| | - Lars O Tjernberg
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Sophia Schedin-Weiss
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
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16
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Tanwar M, Kateriya S, Nair D, Jose M. Optogenetic modulation of real-time nanoscale dynamics of HCN channels using photoactivated adenylyl cyclases. RSC Chem Biol 2021; 2:863-875. [PMID: 34458814 PMCID: PMC8341789 DOI: 10.1039/d0cb00124d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 02/12/2021] [Indexed: 12/12/2022] Open
Abstract
Adenosine 3',5'-cyclic monophosphate (cAMP) is a key second messenger that activates several signal transduction pathways in eukaryotic cells. Alteration of basal levels of cAMP is known to activate protein kinases, regulate phosphodiesterases and modulate the activity of ion channels such as Hyper polarization-activated cyclic nucleotide gated channels (HCN). Recent advances in optogenetics have resulted in the availability of novel genetically encoded molecules with the capability to alter cytoplasmic profiles of cAMP with unprecedented spatial and temporal precision. Using single molecule based super-resolution microscopy and different optogenetic modulators of cellular cAMP in both live and fixed cells, we illustrate a novel paradigm to report alteration in nanoscale confinement of ectopically expressed HCN channels. We characterized the efficacy of cAMP generation using ensemble photoactivation of different optogenetic modulators. Then we demonstrate that local modulation of cAMP alters the exchange of membrane bound HCN channels with its nanoenvironment. Additionally, using high density single particle tracking in combination with both acute and chronic optogenetic elevation of cAMP in the cytoplasm, we show that HCN channels are confined to sub 100 nm sized functional domains on the plasma membrane. The nanoscale properties of these domains along with the exchange kinetics of HCN channels in and out of these molecular zones are altered upon temporal changes in the cytoplasmic cAMP. Using HCN2 point mutants and a truncated construct of HCN2 with altered sensitivity to cAMP, we confirmed these alterations in lateral organization of HCN2 to be specific to cAMP binding. Thus, combining these advanced non-invasive paradigms, we report a cAMP dependent ensemble and single particle behavior of HCN channels mediated by its cyclic nucleotide binding domain, opening innovative ways to dissect biochemical pathways at the nanoscale and real-time in living cells.
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Affiliation(s)
- Meenakshi Tanwar
- Centre for Neuroscience, Indian Institute of Science Bangalore-560012 India
| | - Suneel Kateriya
- Laboratory of Optobiology, School of Biotechnology, Jawaharlal Nehru University New Delhi-110067 India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science Bangalore-560012 India
| | - Mini Jose
- Centre for Neuroscience, Indian Institute of Science Bangalore-560012 India
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17
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Kedia S, Ramanan N, Nair D. Quantifying molecular aggregation by super resolution microscopy within an excitatory synapse from mouse hippocampal neurons. STAR Protoc 2021; 2:100470. [PMID: 33937876 PMCID: PMC8076707 DOI: 10.1016/j.xpro.2021.100470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Super-resolution microscopy (SRM) has been widely adopted to probe molecular distribution at excitatory synapses. We present an SRM paradigm to evaluate the nanoscale organization heterogeneity between neuronal subcompartments. Using mouse hippocampal neurons, we describe the identification of the morphological characteristics of nanodomains within functional zones of a single excitatory synapse. This information can be used to correlate structure and function at molecular resolution in single synapses. The protocol can be applied to immunocytochemical/histochemical samples across different imaging paradigms. For complete details on the use and execution of this protocol, please refer to Kedia et al. (2021).
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Affiliation(s)
- Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | | | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
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18
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Kedia S, Ramakrishna P, Netrakanti PR, Singh N, Sisodia SS, Jose M, Kumar S, Mahadevan A, Ramanan N, Nadkarni S, Nair D. Alteration in synaptic nanoscale organization dictates amyloidogenic processing in Alzheimer's disease. iScience 2020; 24:101924. [PMID: 33409475 PMCID: PMC7773964 DOI: 10.1016/j.isci.2020.101924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/22/2020] [Accepted: 12/07/2020] [Indexed: 01/08/2023] Open
Abstract
Despite intuitive insights into differential proteolysis of amyloid precursor protein (APP), the stochasticity behind local product formation through amyloidogenic pathway at individual synapses remain unclear. Here, we show that the major components of amyloidogenic machinery namely, APP and secretases are discretely organized into nanodomains of high local concentration compared to their immediate environment in functional zones of the synapse. Additionally, with the aid of multiple models of Alzheimer's disease (AD), we confirm that this discrete nanoscale chemical map of amyloidogenic machinery is altered at excitatory synapses. Furthermore, we provide realistic models of amyloidogenic processing in unitary vesicles originating from the endocytic zone of excitatory synapses. Thus, we show how an alteration in the stochasticity of synaptic nanoscale organization contributes to the dynamic range of C-terminal fragments β (CTFβ) production, defining the heterogeneity of amyloidogenic processing at individual synapses, leading to long-term synaptic deficits as seen in AD. Components of amyloidogenic machinery are organized into nanodomains Assembly of nanodomains differs between functional zones of the synapse Stochasticity of nanoscale organization dictates dynamic range of APP proteolysis Variability in composition of amyloidogenic machinery is associated with AD
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Affiliation(s)
- Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | | | | | - Nivedita Singh
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Sangram S Sisodia
- Center for Molecular Neurobiology, Department of Neurobiology, The University of Chicago, IL 60637, USA
| | - Mini Jose
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Sathish Kumar
- Department of Neurology, University of Bonn, Bonn 53127, Germany
| | - Anita Mahadevan
- Department of Neuropathology, NIMHANS, Bangalore 560029, India
| | | | - Suhita Nadkarni
- Indian Institute of Science Education and Research, Pune 411008, India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India
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Preferential Protein Partitioning in Biological Membrane with Coexisting Liquid Ordered and Liquid Disordered Phase Behavior: Underlying Design Principles. J Membr Biol 2020; 253:551-562. [PMID: 33170308 DOI: 10.1007/s00232-020-00150-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/31/2020] [Indexed: 12/17/2022]
Abstract
Several studies now show that certain proteins exhibit selective preference toward liquid ordered (L[Formula: see text]) or toward liquid disordered (L[Formula: see text]) regions of the heterogeneous membrane and some of them have preference for the L[Formula: see text]-L[Formula: see text] interface. Spatially heterogenous organization of lipids, enriched in specific protein molecules, function as platforms for signaling and are involved in several other physiologically critical functions. In this review, we collate together some of the experimental observations of cases where proteins preferentially segregate into different phases and highlight the importance of these preferential localization in terms of underlying functions. We also try to understand the structural features and chemical makeup of the membrane-interacting motifs of these proteins. Finally, we put forth some preliminary analysis on class I viral fusion proteins, some of which are known to partition at the L[Formula: see text]-L[Formula: see text] interface, and through them we try to understand the evolutionary design principles of phase segregating proteins. Put together, this review summarizes the existing studies on preferential partitioning of proteins into different membrane phases while emphasizing the need to understand the molecular design-level features that can help us "engineer" functionally rich peptides and proteins with a programmed membrane partitioning.
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Kedia S, Nair D. Nanoscale rearrangement of APP organization as a therapeutic target for Alzheimer's disease. Med Hypotheses 2020; 143:110143. [PMID: 32759014 DOI: 10.1016/j.mehy.2020.110143] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/16/2020] [Accepted: 07/23/2020] [Indexed: 12/19/2022]
Abstract
Despite the importance of canonical processing of Amyloid Precursor Protein at synapses as a major risk factor for the development of Alzheimer's Disease, there have been very little progress on designing effective therapeutic paradigms targeting it. Majority of the drugs developed or under clinical evaluation focus on the clearance of the detrimental proteoforms or secretases involved in the proteolysis of APP. The lack of interventions targeting APP is in part due to the lack of information in understanding the fine organization of APP and the chemical map of its association with subsynaptic functional zones of the synapse. The recent advances to evaluate the molecular organization of synapses allows us to readdress the need for designing tools to target the full-length APP. Here, we describe the potential role of nanoscale segregation of synaptic APP and how this organization influences the local processing of APP in different subsynaptic compartments opening avenues for early intervention strategies. We envision the need to design smart molecules which would interfere with the real-time chemical composition and physical properties of APP at nanoscale. These tools could alter the balance of proteoforms generated and/or enhance the proteolysis by selective secretases to reduce the toxic products formed through amyloidogenic pathway. We believe that such an approach would be rational to treat or delay the onset of neurodegenerative diseases like AD.
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Affiliation(s)
- Shekhar Kedia
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India.
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India.
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