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Park I, Kim HJ, Shin J, Jung YJ, Lee D, Lim J, Park JM, Park JW, Kim J. AFM Imaging Reveals MicroRNA-132 to be a Positive Regulator of Synaptic Functions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306630. [PMID: 38493494 PMCID: PMC11077659 DOI: 10.1002/advs.202306630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/17/2024] [Indexed: 03/19/2024]
Abstract
The modification of synaptic and neural connections in adults, including the formation and removal of synapses, depends on activity-dependent synaptic and structural plasticity. MicroRNAs (miRNAs) play crucial roles in regulating these changes by targeting specific genes and regulating their expression. The fact that somatic and dendritic activity in neurons often occurs asynchronously highlights the need for spatial and dynamic regulation of protein synthesis in specific milieu and cellular loci. MicroRNAs, which can show distinct patterns of enrichment, help to establish the localized distribution of plasticity-related proteins. The recent study using atomic force microscopy (AFM)-based nanoscale imaging reveals that the abundance of miRNA(miR)-134 is inversely correlated with the functional activity of dendritic spine structures. However, the miRNAs that are selectively upregulated in potentiated synapses, and which can thereby support prospective changes in synaptic efficacy, remain largely unknown. Using AFM force imaging, significant increases in miR-132 in the dendritic regions abutting functionally-active spines is discovered. This study provides evidence for miR-132 as a novel positive miRNA regulator residing in dendritic shafts, and also suggests that activity-dependent miRNAs localized in distinct sub-compartments of neurons play bi-directional roles in controlling synaptic transmission and synaptic plasticity.
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Affiliation(s)
- Ikbum Park
- Technical Support Center for Chemical IndustryKorea Research Institute of Chemical Technology (KRICT)Ulsan44412Republic of Korea
| | - Hyun Jin Kim
- Department of Life SciencesPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
| | - Juyoung Shin
- Department of Life SciencesPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
| | - Yu Jin Jung
- Center for Specialty ChemicalsKorea Research Institute of Chemical Technology (KRICT)Ulsan44412Republic of Korea
| | - Donggyu Lee
- Division of Electronics and Information SystemDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988Republic of Korea
| | - Ji‐seon Lim
- Department of ChemistryPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
| | - Jong Mok Park
- Technical Support Center for Chemical IndustryKorea Research Institute of Chemical Technology (KRICT)Ulsan44412Republic of Korea
| | - Joon Won Park
- Department of ChemistryPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
| | - Joung‐Hun Kim
- Department of Life SciencesPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
- Institute of Convergence ScienceYonsei UniversitySeoul03722Republic of Korea
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2
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Li Z, Zhang L, Wang Z, Kang X, Jin H, Zhao W, Zhang J, Su H. Quantification of Phosphatidylserine Molecules on the Surface of Individual Cells Using Single-Molecule Force Spectroscopy. Anal Chem 2024; 96:676-684. [PMID: 38173079 DOI: 10.1021/acs.analchem.3c03517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Identification of the phosphatidylserine (PS) discrepancies occurring on the cellular membrane during apoptotic processes is of the utmost importance. However, monitoring the quantity of PS molecules in real-time at a single-cell level currently remains a challenging task. Here, we demonstrate this objective by leveraging the specific binding and reversible interaction exhibited by the zinc(II) dipyridinamine complex (ZnDPA) with PS. Lipoic acid-functionalized ZnDPA (LP-ZnDPA) was subsequently immobilized onto the surface of an atomic force microscopy cantilever to form a force probe, ALP-ZnDPA, enabling a PS-specific dynamic imaging and detection mode. By utilizing this technique, we can not only create a heat map of the expression level of PS with submicron resolution but also quantify the number of molecules present on a single cell's surface with a detection limit of 1.86 × 104 molecules. The feasibility of the proposed method is demonstrated through the analysis of PS expression levels in different cancer cell lines and at various stages of paclitaxel-induced apoptosis. This study represents the first application of a force probe to quantify PS molecules on the surface of individual cells, providing insight into dynamic changes in PS content during apoptosis at the molecular level and introducing a novel dimension to current detection methodologies.
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Affiliation(s)
- Zhirong Li
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Lulu Zhang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Zhanzhong Wang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Xiongli Kang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Huiying Jin
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Wenjie Zhao
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Jun Zhang
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
| | - Haiquan Su
- Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010020, China
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Ramsden CE, Zamora D, Horowitz MS, Jahanipour J, Calzada E, Li X, Keyes GS, Murray HC, Curtis MA, Faull RM, Sedlock A, Maric D. ApoER2-Dab1 disruption as the origin of pTau-associated neurodegeneration in sporadic Alzheimer's disease. Acta Neuropathol Commun 2023; 11:197. [PMID: 38093390 PMCID: PMC10720169 DOI: 10.1186/s40478-023-01693-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/16/2023] [Indexed: 12/17/2023] Open
Abstract
In sporadic Alzheimer's disease (sAD) specific regions, layers and neurons accumulate hyperphosphorylated Tau (pTau) and degenerate early while others remain unaffected even in advanced disease. ApoER2-Dab1 signaling suppresses Tau phosphorylation as part of a four-arm pathway that regulates lipoprotein internalization and the integrity of actin, microtubules, and synapses; however, the role of this pathway in sAD pathogenesis is not fully understood. We previously showed that multiple ApoER2-Dab1 pathway components including ApoE, Reelin, ApoER2, Dab1, pP85αTyr607, pLIMK1Thr508, pTauSer202/Thr205 and pPSD95Thr19 accumulate together within entorhinal-hippocampal terminal zones in sAD, and proposed a unifying hypothesis wherein disruption of this pathway underlies multiple aspects of sAD pathogenesis. However, it is not yet known whether ApoER2-Dab1 disruption can help explain the origin(s) and early progression of pTau pathology in sAD. In the present study, we applied in situ hybridization and immunohistochemistry (IHC) to characterize ApoER2 expression and accumulation of ApoER2-Dab1 pathway components in five regions known to develop early pTau pathology in 64 rapidly autopsied cases spanning the clinicopathological spectrum of sAD. We found that (1) these selectively vulnerable neuron populations strongly express ApoER2; and (2) multiple ApoER2-Dab1 components representing all four arms of this pathway accumulate in abnormal neurons and neuritic plaques in mild cognitive impairment (MCI) and sAD cases and correlate with histological progression and cognitive deficits. Multiplex-IHC revealed that Dab1, pP85αTyr607, pLIMK1Thr508, pTauSer202/Thr205 and pPSD95Thr19 accumulate together within many of the same ApoER2-expressing neurons and in the immediate vicinity of ApoE/ApoJ-enriched extracellular plaques. Collective findings reveal that pTau is only one of many ApoER2-Dab1 pathway components that accumulate in multiple neuroanatomical sites in the earliest stages of sAD and provide support for the concept that ApoER2-Dab1 disruption drives pTau-associated neurodegeneration in human sAD.
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Affiliation(s)
- Christopher E Ramsden
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA.
- Intramural Program of the National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, 20892, USA.
| | - Daisy Zamora
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Mark S Horowitz
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Jahandar Jahanipour
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Elizabeth Calzada
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Xiufeng Li
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Gregory S Keyes
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH (NIA/NIH), 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Helen C Murray
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Richard M Faull
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Andrea Sedlock
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
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Ramsden CE, Zamora D, Horowitz M, Jahanipour J, Keyes G, Li X, Murray HC, Curtis MA, Faull RM, Sedlock A, Maric D. ApoER2-Dab1 disruption as the origin of pTau-related neurodegeneration in sporadic Alzheimer's disease. RESEARCH SQUARE 2023:rs.3.rs-2968020. [PMID: 37461602 PMCID: PMC10350181 DOI: 10.21203/rs.3.rs-2968020/v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
BACKGROUND Sporadic Alzheimer's disease (sAD) is not a global brain disease. Specific regions, layers and neurons degenerate early while others remain untouched even in advanced disease. The prevailing model used to explain this selective neurodegeneration-prion-like Tau spread-has key limitations and is not easily integrated with other defining sAD features. Instead, we propose that in humans Tau hyperphosphorylation occurs locally via disruption in ApoER2-Dab1 signaling and thus the presence of ApoER2 in neuronal membranes confers vulnerability to degeneration. Further, we propose that disruption of the Reelin/ApoE/ApoJ-ApoER2-Dab1-P85α-LIMK1-Tau-PSD95 (RAAAD-P-LTP) pathway induces deficits in memory and cognition by impeding neuronal lipoprotein internalization and destabilizing actin, microtubules, and synapses. This new model is based in part on our recent finding that ApoER2-Dab1 disruption is evident in entorhinal-hippocampal terminal zones in sAD. Here, we hypothesized that neurons that degenerate in the earliest stages of sAD (1) strongly express ApoER2 and (2) show evidence of ApoER2-Dab1 disruption through co-accumulation of multiple RAAAD-P-LTP components. METHODS We applied in situ hybridization and immunohistochemistry to characterize ApoER2 expression and accumulation of RAAAD-P-LTP components in five regions that are prone to early pTau pathology in 64 rapidly autopsied cases spanning the clinicopathological spectrum of sAD. RESULTS We found that: (1) selectively vulnerable neuron populations strongly express ApoER2; (2) numerous RAAAD-P-LTP pathway components accumulate in neuritic plaques and abnormal neurons; and (3) RAAAD-P-LTP components were higher in MCI and sAD cases and correlated with histological progression and cognitive deficits. Multiplex-IHC revealed that Dab1, pP85αTyr607, pLIMK1Thr508, pTau and pPSD95Thr19 accumulated together within dystrophic dendrites and soma of ApoER2-expressing neurons in the vicinity of ApoE/ApoJ-enriched extracellular plaques. These observations provide evidence for molecular derangements that can be traced back to ApoER2-Dab1 disruption, in each of the sampled regions, layers, and neuron populations that are prone to early pTau pathology. CONCLUSION Findings support the RAAAD-P-LTP hypothesis, a unifying model that implicates dendritic ApoER2-Dab1 disruption as the major driver of both pTau accumulation and neurodegeneration in sAD. This model provides a new conceptual framework to explain why specific neurons degenerate and identifies RAAAD-P-LTP pathway components as potential mechanism-based biomarkers and therapeutic targets for sAD.
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Affiliation(s)
| | - Daisy Zamora
- National Institute on Aging Laboratory of Clinical Investigation
| | - Mark Horowitz
- National Institute on Aging Intramural Research Program
| | | | - Gregory Keyes
- National Institute on Aging Laboratory of Clinical Investigation
| | - Xiufeng Li
- National Institute on Aging Laboratory of Clinical Investigation
| | - Helen C Murray
- The University of Auckland Faculty of Medical and Health Sciences
| | - Maurice A Curtis
- The University of Auckland Faculty of Medical and Health Sciences
| | - Richard M Faull
- The University of Auckland Faculty of Medical and Health Sciences
| | - Andrea Sedlock
- NINDS: National Institute of Neurological Disorders and Stroke
| | - Dragan Maric
- NINDS: National Institute of Neurological Disorders and Stroke
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5
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Ramsden CE, Zamora D, Horowitz MS, Jahanipour J, Keyes GS, Li X, Murray HC, Curtis MA, Faull RM, Sedlock A, Maric D. ApoER2-Dab1 disruption as the origin of pTau-related neurodegeneration in sporadic Alzheimer's disease. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.19.23290250. [PMID: 37333406 PMCID: PMC10274982 DOI: 10.1101/2023.05.19.23290250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
BACKGROUND Sporadic Alzheimer's disease (sAD) is not a global brain disease. Specific regions, layers and neurons degenerate early while others remain untouched even in advanced disease. The prevailing model used to explain this selective neurodegeneration-prion-like Tau spread-has key limitations and is not easily integrated with other defining sAD features. Instead, we propose that in humans Tau hyperphosphorylation occurs locally via disruption in ApoER2-Dab1 signaling and thus the presence of ApoER2 in neuronal membranes confers vulnerability to degeneration. Further, we propose that disruption of the Reelin/ApoE/ApoJ-ApoER2-Dab1-P85α-LIMK1-Tau-PSD95 (RAAAD-P-LTP) pathway induces deficits in memory and cognition by impeding neuronal lipoprotein internalization and destabilizing actin, microtubules, and synapses. This new model is based in part on our recent finding that ApoER2-Dab1 disruption is evident in entorhinal-hippocampal terminal zones in sAD. Here, we hypothesized that neurons that degenerate in the earliest stages of sAD (1) strongly express ApoER2 and (2) show evidence of ApoER2-Dab1 disruption through co-accumulation of multiple RAAAD-P-LTP components. METHODS We applied in situ hybridization and immunohistochemistry to characterize ApoER2 expression and accumulation of RAAAD-P-LTP components in five regions that are prone to early pTau pathology in 64 rapidly autopsied cases spanning the clinicopathological spectrum of sAD. RESULTS We found that: (1) selectively vulnerable neuron populations strongly express ApoER2; (2) numerous RAAAD-P-LTP pathway components accumulate in neuritic plaques and abnormal neurons; and (3) RAAAD-P-LTP components were higher in MCI and sAD cases and correlated with histological progression and cognitive deficits. Multiplex-IHC revealed that Dab1, pP85αTyr607, pLIMK1Thr508, pTau and pPSD95Thr19 accumulated together within dystrophic dendrites and soma of ApoER2-expressing neurons in the vicinity of ApoE/ApoJ-enriched extracellular plaques. These observations provide evidence for molecular derangements that can be traced back to ApoER2-Dab1 disruption, in each of the sampled regions, layers, and neuron populations that are prone to early pTau pathology. CONCLUSION Findings support the RAAAD-P-LTP hypothesis, a unifying model that implicates dendritic ApoER2-Dab1 disruption as the major driver of both pTau accumulation and neurodegeneration in sAD. This model provides a new conceptual framework to explain why specific neurons degenerate and identifies RAAAD-P-LTP pathway components as potential mechanism-based biomarkers and therapeutic targets for sAD.
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Affiliation(s)
- Christopher E. Ramsden
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH 251 Bayview Blvd., Baltimore, MD, 21224, USA
- Intramural Program of the National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, 20892, USA
| | - Daisy Zamora
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH 251 Bayview Blvd., Baltimore, MD, 21224, USA
- Department of Physical Medicine and Rehabilitation, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Mark S. Horowitz
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Jahandar Jahanipour
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Gregory S. Keyes
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Xiufeng Li
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Helen C. Murray
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Maurice A. Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Richard M. Faull
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Private Bag, Auckland, 92019, New Zealand
| | - Andrea Sedlock
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA
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Dumitru AC, Koehler M. Recent advances in the application of atomic force microscopy to structural biology. J Struct Biol 2023; 215:107963. [PMID: 37044358 DOI: 10.1016/j.jsb.2023.107963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/21/2023] [Accepted: 04/07/2023] [Indexed: 04/14/2023]
Abstract
The application of atomic force microscopy (AFM) for (functional) imaging and manipulating biomolecules at all levels of organization has enabled great progress in the structural biology field over the last decades, contributing to the discovery of novel structural entities of biological significance across many disciplines ranging from biochemistry, biomedicine and biophysics to molecular and cell biology, up to food systems and beyond. AFM has the capability to generate high-resolution topographic images spanning from the submolecular to the (sub)cellular range and can probe biochemical and biophysical sample properties in close to native conditions with excellent temporal resolution. Instrumental developments in the past decade enable dynamical structural and conformational studies of single biomolecules and new techniques for structural and chemical modification of the AFM probe have converted the cantilever into a versatile tool to study different biological phenomena, such as the mechanical stability of biomolecular complexes or the force induced dynamic changes of mechanically stressed proteins at the nanoscopic level. To improve the functionality of AFM and approach dynamic processes of complex biological systems ex vivo, AFM is combined with complementary microscopy, nanoscopy and spectroscopy tools. These multimethodological approaches provide unprecedented possibilities of probing physical, chemical and biological properties of complex cellular systems with high spatio-temporal resolution, leading to novel applications that correlate structural results with functional biochemical, biophysical, immunological, or genetic data on the system under study.
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Affiliation(s)
- Andra C Dumitru
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain.
| | - Melanie Koehler
- Leibniz Institute for Food Systems Biology at the Technical University Munich, Freising, Germany.
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Molecular Recognition of Surface Trans-Sialidases in Extracellular Vesicles of the Parasite Trypanosoma cruzi Using Atomic Force Microscopy (AFM). Int J Mol Sci 2022; 23:ijms23137193. [PMID: 35806197 PMCID: PMC9266976 DOI: 10.3390/ijms23137193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/23/2022] [Accepted: 06/26/2022] [Indexed: 02/06/2023] Open
Abstract
Trans-sialidases (TS) are important constitutive macromolecules of the secretome present on the surface of Trypanosoma cruzi (T. cruzi) that play a central role as a virulence factor in Chagas disease. These enzymes have been related to infectivity, escape from immune surveillance and pathogenesis exhibited by this protozoan parasite. In this work, atomic force microscopy (AFM)-based single molecule-force spectroscopy is implemented as a suitable technique for the detection and location of functional TS on the surface of extracellular vesicles (EVs) released by tissue-culture cell-derived trypomastigotes (Ex-TcT). For that purpose, AFM cantilevers with functionalized tips bearing the anti-TS monoclonal antibody mAb 39 as a sense biomolecule are engineered using a covalent chemical ligation based on vinyl sulfonate click chemistry; a reliable, simple and efficient methodology for the molecular recognition of TS using the antibody-antigen interaction. Measurements of the breakdown forces between anti-TS mAb 39 antibodies and EVs performed to elucidate adhesion and forces involved in the recognition events demonstrate that EVs isolated from tissue-culture cell-derived trypomastigotes of T. cruzi are enriched in TS. Additionally, a mapping of the TS binding sites with submicrometer-scale resolution is provided. This work represents the first AFM-based molecular recognition study of Ex-TcT using an antibody-tethered AFM probe.
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