Browsing by Author "Klingstedt, Therése"
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Item Distinct Chemical Determinants are Essential for Achieving Ligands for Superior Optical Detection of Specific Amyloid-β Deposits in Alzheimer's Disease(Wiley, 2024) Wu, Xiongyu; Shirani, Hamid; Vidal, Ruben; Ghetti, Bernardino; Ingelsson, Martin; Klingstedt, Therése; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineAggregated forms of different proteins are common hallmarks for several neurodegenerative diseases, including Alzheimer's disease, and ligands that selectively detect specific protein aggregates are vital. Herein, we investigate the molecular requirements of thiophene-vinyl-benzothiazole based ligands to detect a specific type of Aβ deposits found in individuals with dominantly inherited Alzheimer's disease caused by the Arctic APP E693G mutation. The staining of these Aβ deposits was alternated when switching the terminal heterocyclic moiety attached to the thiophene-vinyl-benzothiazole scaffold. The most prevalent staining was observed for ligands having a terminal 3-methyl-1H-indazole moiety or a terminal 1,2-dimethoxybenzene moiety, verifying that specific molecular interactions between these ligands and the aggregates were necessary. The synthesis of additional thiophene-vinyl-benzothiazole ligands aided in pinpointing additional crucial chemical determinants, such as positioning of nitrogen atoms and methyl substituents, for achieving optimal staining of Aβ aggregates. When combining the optimized thiophene-vinyl-benzothiazole based ligands with a conventional ligand, CN-PiB, distinct staining patterns were observed for sporadic Alzheimer's disease versus dominantly inherited Alzheimer's disease caused by the Arctic APP E693G mutation. Our findings provide chemical insights for developing novel ligands that allow for a more precise assignment of Aβ deposits, and might also aid in creating novel agents for clinical imaging of distinct Aβ aggregates in AD.Item Distinct Heterocyclic Moieties Govern the Selectivity of Thiophene-Vinylene-Based Ligands Towards Aβ or Tau Pathology in Alzheime’s Disease(Wiley, 2023) Björk, Linnea; Shirani, Hamid; Todarwal, Yogesh; Linares, Mathieu; Vidal, Ruben; Ghetti, Bernardino; Norman, Patrick; Klingstedt, Therése; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineDistinct aggregated proteins are correlated with numerous neurodegenerative diseases and the development of ligands that selectively detect these pathological hallmarks is vital. Recently, the synthesis of thiophene-based optical ligands, denoted bi-thiophene-vinyl-benzothiazoles (bTVBTs), that could be utilized for selective assignment of tau pathology in brain tissue with Alzheime's disease (AD) pathology, was reported. Herein, we investigate the ability of these ligands to selectively distinguish tau deposits from aggregated amyloid-β (Aβ), the second AD associated pathological hallmark, when replacing the terminal thiophene moiety with other heterocyclic motifs. The selectivity for tau pathology was reduced when introducing specific heterocyclic motifs, verifying that specific molecular interactions between the ligands and the aggregates are necessary for selective detection of tau deposits. In addition, ligands having certain heterocyclic moieties attached to the central thiophene-vinylene building block displayed selectivity to aggregated Aβ pathology. Our findings provide chemical insights for the development of ligands that can distinguish between aggregated proteinaceous species consisting of different proteins and might also aid in creating novel agents for clinical imaging of tau pathology in AD.Item Dual-ligand fluorescence microscopy enables chronological and spatial histological assignment of distinct amyloid-β deposits(Elsevier, 2025) Klingstedt, Therése; Shirani, Hamid; Parvin, Farjana; Nyström, Sofie; Hammarström, Per; Graff, Caroline; Ingelsson, Martin; Vidal, Ruben; Ghetti, Bernardino; Sehlin, Dag; Syvänen, Stina; Nilsson, K. Peter. R.; Pathology and Laboratory Medicine, School of MedicineDifferent types of deposits comprised of amyloid-β (Aβ) peptides are one of the pathological hallmarks of Alzheimer's disease (AD) and novel methods that enable identification of a diversity of Aβ deposits during the AD continuum are essential for understanding the role of these aggregates during the pathogenesis. Herein, different combinations of five fluorescent thiophene-based ligands were used for detection of Aβ deposits in brain tissue sections from transgenic mouse models with aggregated Aβ pathology, as well as brain tissue sections from patients affected by sporadic or dominantly inherited AD. When analyzing the sections with fluorescence microscopy, distinct ligand staining patterns related to the transgenic mouse model or to the age of the mice were observed. Likewise, specific staining patterns of different Aβ deposits were revealed for sporadic versus dominantly inherited AD, as well as for distinct brain regions in sporadic AD. Thus, by using dual-staining protocols with multiple combinations of fluorescent ligands, a chronological and spatial histological designation of different Aβ deposits could be achieved. This study demonstrates the potential of our approach for resolving the role and presence of distinct Aβ aggregates during the AD continuum and pinpoints the necessity of using multiple ligands to obtain an accurate assignment of different Aβ deposits in the neuropathological evaluation of AD, as well as when evaluating therapeutic strategies targeting Aβ aggregates.Item Luminescent conjugated oligothiophenes distinguish between α-synuclein assemblies of Parkinson’s disease and multiple system atrophy(BMC, 2019-12-03) Klingstedt, Therése; Ghetti, Bernardino; Holton, Janice L.; Ling, Helen; Nilsson, K. Peter R.; Goedert, Michel; Pathology and Laboratory Medicine, School of MedicineSynucleinopathies [Parkinson’s disease with or without dementia, dementia with Lewy bodies and multiple system atrophy] are neurodegenerative diseases that are defined by the presence of filamentous α-synuclein inclusions. We investigated the ability of luminescent conjugated oligothiophenes to stain the inclusions of Parkinson’s disease and multiple system atrophy. They stained the Lewy pathology of Parkinson’s disease and the glial cytoplasmic inclusions of multiple system atrophy. Spectral analysis of HS-68-stained inclusions showed a red shift in multiple system atrophy, but the difference with Parkinson’s disease was not significant. However, when inclusions were double-labelled for HS-68 and an antibody specific for α-synuclein phosphorylated at S129, they could be distinguished based on colour shifts with blue designated for Parkinson’s disease and red for multiple system atrophy. The inclusions of Parkinson’s disease and multiple system atrophy could also be distinguished using fluorescence lifetime imaging. These findings are consistent with the presence of distinct conformers of assembled α-synuclein in Parkinson’s disease and multiple system atrophy.Item Mutation ∆K281 in MAPT causes Pick’s disease(Springer, 2023) Schweighauser, Manuel; Garringer, Holly J.; Klingstedt, Therése; Nilsson, K. Peter R.; Masuda‑Suzukake, Masami; Murrell, Jill R.; Risacher, Shannon L.; Vidal, Ruben; Scheres, Sjors H. W.; Goedert, Michel; Ghetti, Bernardino; Newell, Kathy L.; Pathology and Laboratory Medicine, School of MedicineTwo siblings with deletion mutation ∆K281 in MAPT developed frontotemporal dementia. At autopsy, numerous inclusions of hyperphosphorylated 3R Tau were present in neurons and glial cells of neocortex and some subcortical regions, including hippocampus, caudate/putamen and globus pallidus. The inclusions were argyrophilic with Bodian silver, but not with Gallyas-Braak silver. They were not labelled by an antibody specific for tau phosphorylated at S262 and/or S356. The inclusions were stained by luminescent conjugated oligothiophene HS-84, but not by bTVBT4. Electron cryo-microscopy revealed that the core of tau filaments was made of residues K254-F378 of 3R Tau and was indistinguishable from that of Pick's disease. We conclude that MAPT mutation ∆K281 causes Pick's disease.Item Proteophenes - Amino Acid Functionalized Thiophene-based Fluorescent Ligands for Visualization of Protein Deposits in Tissue Sections with Alzheimer's Disease Pathology(Wiley, 2022) Björk, Linnea; Bäck, Marcus; Lantz, Linda; Ghetti, Bernardino; Vidal, Ruben; Klingstedt, Therése; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineProtein deposits composed of specific proteins or peptides are associated with several neurodegenerative diseases and fluorescent ligands able to detect these pathological hallmarks are vital. Here, we report the synthesis of a class of thiophene-based ligands, denoted proteophenes, with different amino acid side-chain functionalities along the conjugated backbone, which display selectivity towards specific disease-associated protein aggregates in tissue sections with Alzheimer's disease (AD) pathology. The selectivity of the ligands towards AD associated pathological hallmarks, such as aggregates of the amyloid-β (Aβ) peptide or tau filamentous inclusions, was highly dependent on the chemical nature of the amino acid functionality, as well as on the location of the functionality along the pentameric thiophene backbone. Finally, the concept of synthesizing donor-acceptor-donor proteophenes with distinct photophysical properties was shown. Our findings provide the structural and functional basis for the development of new thiophene-based ligands that can be utilized for optical assignment of different aggregated proteinaceous species in tissue sections.Item Tau Protein Binding Modes in Alzheimer's Disease for Cationic Luminescent Ligands(American Chemical Society, 2021) Todarwal, Yogesh; Gustafsson, Camilla; Minh, Nghia Nguyen Thi; Ertzgaard, Ingrid; Klingstedt, Therése; Ghetti, Bernardino; Vidal, Ruben; König, Carolin; Lindgren, Mikael; Nilsson, K. Peter R.; Linares, Mathieu; Norman, Patrick; Pathology and Laboratory Medicine, School of MedicineThe bi-thiophene-vinylene-benzothiazole (bTVBT4) ligand developed for Alzheimer's disease (AD)-specific detection of amyloid tau has been studied by a combination of several theoretical methods and experimental spectroscopies. With reference to the cryo-EM tau structure of the tau protofilament ( Nature 2017, 547, 185), a periodic model system of the fibril was created, and the interactions between this fibril and bTVBT4 were studied with nonbiased molecular dynamics simulations. Several binding sites and binding modes were identified and analyzed, and the results for the most prevailing fibril site and ligand modes are presented. A key validation of the simulation work is provided by the favorable comparison of the theoretical and experimental absorption spectra of bTVBT4 in solution and bound to the protein. It is conclusively shown that the ligand-protein binding occurs at the hydrophobic pocket defined by the residues Ile360, Thr361, and His362. This binding site is not accessible in the Pick's disease (PiD) fold, and fluorescence imaging of bTVBT4-stained brain tissue samples from patients diagnosed with AD and PiD provides strong support for the proposed tau binding site.Item Thiophene-Based Ligands for Histological Multiplex Spectral Detection of Distinct Protein Aggregates in Alzheimer′s Disease(Wiley, 2023) Lantz, Linda; Shirani, Hamid; Ghetti, Bernardino; Vidal, Ruben; Klingstedt, Therése; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineThe aggregation and accumulation of proteins in the brain is the defining feature of many devastating neurodegenerative diseases. The development of fluorescent ligands that bind to these accumulations, or deposits, is essential for the characterization of these neuropathological lesions. We report the synthesis of donor-acceptor-donor (D-A-D) thiophene-based ligands with different emission properties. The D-A-D ligands displayed selectivity towards distinct disease-associated protein deposits in histological sections from postmortem brain tissue of individuals affected by Alzheimer's disease (AD). The ability of the ligands to selectively identify AD-associated pathological alterations, such as deposits composed of aggregates of the amyloid-β (Aβ) peptide or tau, was reduced when the chemical composition of the ligands was altered. When combining the D-A-D ligands with conventional thiophene-based ligands, superior spectral separation of distinct protein aggregates in AD tissue sections was obtained. Our findings provide the structural and functional basis for the development of new fluorescent ligands that can distinguish between aggregated proteinaceous species, as well as offer novel strategies for developing multiplex fluorescence detection of protein aggregates in tissue sections.Item Thiophene-Based Ligands for Specific Assignment of Distinct Aβ Pathologies in Alzheimer's Disease(American Chemical Society, 2024) Klingstedt, Therése; Lantz, Linda; Shirani, Hamid; Ge, Junyue; Hanrieder, Jörg; Vidal, Ruben; Ghetti, Bernardino; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineAggregated species of amyloid-β (Aβ) are one of the pathological hallmarks in Alzheimer's disease (AD), and ligands that selectively target different Aβ deposits are of great interest. In this study, fluorescent thiophene-based ligands have been used to illustrate the features of different types of Aβ deposits found in AD brain tissue. A dual-staining protocol based on two ligands, HS-276 and LL-1, with different photophysical and binding properties, was developed and applied on brain tissue sections from patients affected by sporadic AD or familial AD associated with the PSEN1 A431E mutation. When binding to Aβ deposits, the ligands could easily be distinguished for their different fluorescence, and distinct staining patterns were revealed for these two types of AD. In sporadic AD, HS-276 consistently labeled all immunopositive Aβ plaques, whereas LL-1 mainly stained cored and neuritic Aβ deposits. In the PSEN1 A431E cases, each ligand was binding to specific types of Aβ plaques. The ligand-labeled Aβ deposits were localized in distinct cortical layers, and a laminar staining pattern could be seen. Biochemical characterization of the Aβ aggregates in the individual layers also showed that the variation of ligand binding properties was associated with certain Aβ peptide signatures. For the PSEN1 A431E cases, it was concluded that LL-1 was binding to cotton wool plaques, whereas HS-276 mainly stained diffuse Aβ deposits. Overall, our findings showed that a combination of ligands was essential to identify distinct aggregated Aβ species associated with different forms of AD.Item Thiophene‐Based Optical Ligands That Selectively Detect Aβ Pathology in Alzheimer's Disease(Wiley, 2021-08-03) Klingstedt, Therése; Shirani, Hamid; Ghetti, Bernardino; Nilsson, K. Peter R.; Pathology and Laboratory Medicine, School of MedicineIn several neurodegenerative diseases, the presence of aggregates of specific proteins in the brain is a significant pathological hallmark; thus, developing ligands able to bind to the aggregated proteins is essential for any effort related to imaging and therapeutics. Here we report the synthesis of thiophene‐based ligands containing nitrogen heterocycles. The ligands selectively recognized amyloid‐β (Aβ) aggregates in brain tissue from individuals diagnosed neuropathologically as having Alzheimer's disease (AD). The selectivity for Aβ was dependent on the position of nitrogen in the heterocyclic compounds, and the ability to bind Aβ was shown to be reduced when introducing anionic substituents on the thiophene backbone. Our findings provide the structural and functional basis for the development of ligands that can differentiate between aggregated proteinaceous species comprised of distinct proteins. These ligands might also be powerful tools for studying the pathogenesis of Aβ aggregation and for designing molecules for imaging of Aβ pathology.