| 1. |
- Andersson, Maria, et al.
(författare)
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Synthesis and bioanalytical evaluation of morphine-3-O-sulfate and morphine-6-O-sulfate in human urine and plasma using LC-MS/MS
- 2012
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Ingår i: Journal of Separation Science. - : Wiley. - 1615-9306 .- 1615-9314. ; 35:3, s. 367-375
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to synthesize morphine-3-O-sulfate and morphine-6-O-sulfate for use as reference substances, and to determine the sulfate conjugates as possible heroin and morphine metabolites in plasma and urine by a validated LC-MS/MS method. Morphine-6-O-sulfate and morphine-3-O-sulfate were prepared as dihydrates from morphine hydrochloride, in overall yields of 41 and 39% with product purities of >99.5% and >98%, respectively. For bioanalysis, the chromatographic system consisted of a reversed-phase column and gradient elution. The tandem mass spectrometer was operated in the positive electrospray mode using selected reaction monitoring, of transition m/z 366.15 to 286.40. The measuring range was 5500?ng/mL for morphine-3-O-sulfate and 4.5454?ng/mL for morphine-6-O-sulfate in plasma. In urine, the measuring range was 505000?ng/mL for morphine-3-O-sulfate and 45.44544?ng/mL for morphine-6-O-sulfate. The intra-assay and total imprecision (coefficient of variation) was below 11% for both analytes in urine and plasma. Quantifiable levels of morphine-3-O-sulfate in authentic urine and plasma samples were found. Only one authentic urine sample contained a detectable level of morphine-6-O-sulfate, while no detectable morphine-6-O-sulfate was found in plasma samples.
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| 2. |
- Björk, Linnea, et al.
(författare)
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Distinct Heterocyclic Moieties Govern the Selectivity of Thiophene‐Vinylene‐Based Ligands towards Aβ or Tau Pathology in Alzheimer's Disease
- 2023
-
Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; 26:41, s. e202300583-
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Tidskriftsartikel (refereegranskat)abstract
- Distinct 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 Alzheimer'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.
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| 3. |
- Butina, Karen, et al.
(författare)
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Optotracing for selective fluorescence-based detection, visualization and quantification of live S. aureus in real-time
- 2020
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Ingår i: npj Biofilms and Microbiomes. - : Nature Research. - 2055-5008. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Methods for bacterial detection are needed to advance the infection research and diagnostics. Based on conformation-sensitive fluorescent tracer molecules, optotracing was recently established for dynamic detection and visualization of structural amyloids and polysaccharides in the biofilm matrix of gram-negative bacteria. Here, we extend the use of optotracing for detection of gram-positive bacteria, focussing on the clinically relevant opportunistic human pathogen Staphylococcus aureus. We identify a donor-acceptor-donor-type optotracer, whose binding-induced fluorescence enables real-time detection, quantification, and visualization of S. aureus in monoculture and when mixed with gram-negative Salmonella Enteritidis. An algorithm-based automated high-throughput screen of 1920 S. aureus transposon mutants recognized the cell envelope as the binding target, which was corroborated by super-resolution microscopy of bacterial cells and spectroscopic analysis of purified cell wall components. The binding event was essentially governed by hydrophobic interactions, which permitted custom-designed tuning of the binding selectivity towards S. aureus versus Enterococcus faecalis by appropriate selection of buffer conditions. Collectively this work demonstrates optotracing as an enabling technology relevant for any field of basic and applied research, where visualization and detection of S. aureus is needed.
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| 4. |
- Butina, Karen, et al.
(författare)
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Structural Properties Dictating Selective Optotracer Detection of Staphylococcus aureus
- 2022
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 23:11
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Tidskriftsartikel (refereegranskat)abstract
- Optotracers are conformation-sensitive fluorescent tracer molecules that detect peptide- and carbohydrate-based biopolymers. Their binding to bacterial cell walls allows selective detection and visualisation of Staphylococcus aureus (S. aureus). Here, we investigated the structural properties providing optimal detection of S. aureus. We quantified spectral shifts and fluorescence intensity in mixes of bacteria and optotracers, using automatic peak analysis, cross-correlation, and area-under-curve analysis. We found that the length of the conjugated backbone and the number of charged groups, but not their distribution, are important factors for selective detection of S. aureus. The photophysical properties of optotracers were greatly improved by incorporating a donor-acceptor-donor (D-A-D)-type motif in the conjugated backbone. With significantly reduced background and binding-induced on-switch of fluorescence, these optotracers enabled real-time recordings of S. aureus growth. Collectively, this demonstrates that chemical structure and photophysics are key tunable characteristics in the development of optotracers for selective detection of bacterial species.
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| 5. |
- Calvo-Rodriguez, Maria, et al.
(författare)
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In vivo detection of tau fibrils and amyloid beta aggregates with luminescent conjugated oligothiophenes and multiphoton microscopy
- 2019
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Ingår i: Acta neuropathologica communications. - : BMC. - 2051-5960. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The detection of amyloid beta deposits and neurofibrillary tangles, both hallmarks of Alzheimers disease (AD), is key to understanding the mechanisms underlying these pathologies. Luminescent conjugated oligothiophenes (LCOs) enable fluorescence imaging of these protein aggregates. Using LCOs and multiphoton microscopy, individual tangles and amyloid beta deposits were labeled in vivo and imaged longitudinally in a mouse model of tauopathy and cerebral amyloidosis, respectively. Importantly, LCO HS-84, whose emission falls in the green region of the spectrum, allowed for the first time longitudinal imaging of tangle dynamics following a single intravenous injection. In addition, LCO HS-169, whose emission falls in the red region of the spectrum, successfully labeled amyloid beta deposits, allowing multiplexing with other reporters whose emission falls in the green region of the spectrum. In conclusion, this method can provide a new approach for longitudinal in vivo imaging using multiphoton microscopy of AD pathologies as well as other neurodegenerative diseases associated with protein aggregation in mouse models.
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| 6. |
- Calvo-Rodriguez, Maria, et al.
(författare)
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Real-time imaging of mitochondrial redox reveals increased mitochondrial oxidative stress associated with amyloid ß aggregates in vivo in a mouse model of Alzheimer's disease
- 2024
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Ingår i: Molecular Neurodegeneration. - : BMC. - 1750-1326. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundReactive oxidative stress is a critical player in the amyloid beta (A beta) toxicity that contributes to neurodegeneration in Alzheimer's disease (AD). Damaged mitochondria are one of the main sources of reactive oxygen species and accumulate in A beta plaque-associated dystrophic neurites in the AD brain. Although A beta causes neuronal mitochondria reactive oxidative stress in vitro, this has never been directly observed in vivo in the living mouse brain. Here, we tested for the first time whether A beta plaques and soluble A beta oligomers induce mitochondrial oxidative stress in surrounding neurons in vivo, and whether this neurotoxic effect can be abrogated using mitochondrial-targeted antioxidants.MethodsWe expressed a genetically encoded fluorescent ratiometric mitochondria-targeted reporter of oxidative stress in mouse models of the disease and performed intravital multiphoton microscopy of neuronal mitochondria and A beta plaques.ResultsFor the first time, we demonstrated by direct observation in the living mouse brain exacerbated mitochondrial oxidative stress in neurons after both A beta plaque deposition and direct application of soluble oligomeric A beta onto the brain, and determined the most likely pathological sequence of events leading to oxidative stress in vivo. Oxidative stress could be inhibited by both blocking calcium influx into mitochondria and treating with the mitochondria-targeted antioxidant SS31. Remarkably, the latter ameliorated plaque-associated dystrophic neurites without impacting A beta plaque burden.ConclusionsConsidering these results, combination of mitochondria-targeted compounds with other anti-amyloid beta or anti-tau therapies hold promise as neuroprotective drugs for the prevention and/or treatment of AD.
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| 7. |
- Choong, Ferdinand X., et al.
(författare)
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Stereochemical Identification of Glucans by a Donor-Acceptor-Donor Conjugated Pentamer Enables Multi-Carbohydrate Anatomical Mapping in Plant Tissues
- 2019
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Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 26:7, s. 4253-4264
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Tidskriftsartikel (refereegranskat)abstract
- Optotracing is a novel method for analytical imaging of carbohydrates in plant and microbial tissues. This optical method applies structure-responsive oligothiophenes as molecular fluorophores emitting unique optical signatures when bound to polysaccharides. Herein, we apply Carbotrace680, a short length anionic oligothiophene with a central heterocyclic benzodithiazole (BTD) motif, to probe for different glucans. The donor-acceptor-donor type electronic structure of Carbotrace680 provides improved spectral properties compared to oligothiophenes due to the possibility of intramolecular charge-transfer transition to the BTD motif. This enables differentiation of glucans based on the glycosidic linkage stereochemistry. Thus -configured starch is readily differentiated from -configured cellulose. The versatility of optotracing is demonstrated by dynamic monitoring of thermo-induced starch remodelling, shown in parallel by spectrophotometry and microscopy of starch granules. Imaging of Carbotrace680 bound to multiple glucans in plant tissues provided direct identification of their physical locations, revealing the spatial relationship between structural (cellulose) and storage (starch) glucans at sub-cellular scale. Our work forms the basis for the development of superior optotracers for sensitive detection of polysaccharides. Our non-destructive method for anatomical mapping of glucans in biomass will serve as an enabling technology for developments towards efficient use of plant-derived materials and biomass.
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| 8. |
- Farhangi, Hadis, et al.
(författare)
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Optimizing growth conditions in vertical farming: enhancing lettuce and basil cultivation through the application of the Taguchi method
- 2023
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Ingår i: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the findings of an experimental study that investigated the impact of various environmental factors on the growth of lettuce and basil plants in vertical farms. The study employed the Taguchi method, a statistical design of experiments approach, to efficiently identify the optimal growth conditions for these crops in a hyper-controlled environment. By reducing the time and cost of designing and running experiments, this method allowed for the simultaneous investigation of multiple environmental factors that affect plant growth. A total of 27 treatments were selected using the Taguchi approach, and the signal to noise ratio was calculated to predict the optimal levels of each environmental condition for maximizing basil and lettuce growth parameters. The results showed that most of the parameters, except for EC and relative humidity for certain growth parameters, were interrelated with each other. To validate the results, confirmation tests were conducted based on the predicted optimal parameters. The low error ratio between expected and predicted values (1-3%) confirmed the effectiveness of the Taguchi approach for determining the optimal environmental conditions for plant growth in vertical farms.
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| 9. |
- Faustini, Gaia, et al.
(författare)
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Synapsin III gene silencing redeems alpha-synuclein transgenic mice from Parkinsons disease-like phenotype
- 2022
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Ingår i: Molecular Therapy. - : Cell Press. - 1525-0016 .- 1525-0024. ; 30:4, s. 1465-1483
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Tidskriftsartikel (refereegranskat)abstract
- Fibrillary aggregated alpha-synuclein (alpha-syn) deposition in Lewy bodies (LB) characterizes Parkinsons disease (PD) and is believed to trigger dopaminergic synaptic failure and a retrograde terminal-to-cell body neuronal degeneration. We described that the neuronal phosphoprotein synapsin III (Syn III) cooperates with alpha-syn to regulate dopamine (DA) release and can be found in the insoluble alpha-syn fibrils composing LB. Moreover, we showed that a-syn aggregates deposition, and the associated onset of synaptic deficits and neuronal degeneration occurring following adeno-associated viral vectors-mediated overexpression of human alpha-syn in the nigrostriatal system are hindered in Syn III knock out mice. This supports that Syn III facilitates alpha-syn aggregation. Here, in an interventional experimental design, we found that by inducing the gene silencing of Syn III in human alpha-syn transgenic mice at PD-like stage with advanced alpha-syn aggregation and overt striatal synaptic failure, we could lower alpha-syn aggregates and striatal fibers loss. In parallel, we observed recovery from synaptic vesicles clumping, DA release failure, and motor functions impairment. This supports that Syn III consolidates alpha-syn aggregates, while its downregulation enables their reduction and redeems the PD-like phenotype. Strategies targeting Syn III could thus constitute a therapeutic option for PD.
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| 10. |
- Gomez-Gutierrez, Ruben, et al.
(författare)
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Two structurally defined A & beta; polymorphs promote different pathological changes in susceptible mice
- 2023
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Ingår i: EMBO Reports. - : WILEY. - 1469-221X .- 1469-3178. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- Misfolded A & beta; is involved in the progression of Alzheimers disease (AD). However, the role of its polymorphic variants or conformational strains in AD pathogenesis is not fully understood. Here, we study the seeding properties of two structurally defined synthetic misfolded A & beta; strains (termed 2F and 3F) using in vitro and in vivo assays. We show that 2F and 3F strains differ in their biochemical properties, including resistance to proteolysis, binding to strain-specific dyes, and in vitro seeding. Injection of these strains into a transgenic mouse model produces different pathological features, namely different rates of aggregation, formation of different plaque types, tropism to specific brain regions, differential recruitment of A & beta;(40)/A & beta;(42) peptides, and induction of microglial and astroglial responses. Importantly, the aggregates induced by 2F and 3F are structurally different as determined by ssNMR. Our study analyzes the biological properties of purified A & beta; polymorphs that have been characterized at the atomic resolution level and provides relevant information on the pathological significance of misfolded A & beta; strains.
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| 11. |
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| 12. |
- Gustafsson, Camilla, et al.
(författare)
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Deciphering the Electronic Transitions of Thiophene-Based Donor-Acceptor-Donor Pentameric Ligands Utilized for Multimodal Fluorescence Microscopy of Protein Aggregates
- 2021
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Ingår i: ChemPhysChem. - : Wiley-VCH Verlag. - 1439-4235 .- 1439-7641. ; 22:3, s. 323-335
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Tidskriftsartikel (refereegranskat)abstract
- Anionic pentameric thiophene acetates can be used for fluorescence detection and diagnosis of protein amyloid aggregates. Replacing the central thiophene unit by benzothiadiazole (BTD) or quinoxaline (QX) leads to large emission shifts and basic spectral features have been reported [Chem. Eur. J. 2015, 21, 15133-13137]. Here we present new detailed experimental results of solvent effects, time-resolved fluorescence and examples employing multi-photon microscopy and lifetime imaging. Quantum chemical response calculations elucidate how the introduction of the BTD/QX groups changes the electronic states and emissions. The dramatic red-shift follows an increased conjugation and quinoid character of the π-electrons of the thiophene backbone. An efficient charge transfer in the excited states S1 and S2 compared to the all-thiophene analogue makes these more sensitive to the polarity and quenching by the solvent. Taken together, the results guide in the interpretation of images of stained Alzheimer disease brain sections employing advanced fluorescence microscopy and lifetime imaging, and can aid in optimizing future fluorescent ligand development.
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| 13. |
- Herrmann, Uli S., et al.
(författare)
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Structure-based drug design identifies polythiophenes as antiprion compounds
- 2015
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 7:299, s. 299ra123-
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Tidskriftsartikel (refereegranskat)abstract
- Prions cause transmissible spongiform encephalopathies for which no treatment exists. Prions consist of PrPSc, a misfolded and aggregated form of the cellular prion protein (PrPC). We explore the antiprion properties of luminescent conjugated polythiophenes (LCPs) that bind and stabilize ordered protein aggregates. By administering a library of structurally diverse LCPs to the brains of prion-infected mice via osmotic minipumps, we found that antiprion activity required a minimum of five thiophene rings bearing regularly spaced carboxyl side groups. Solid-state nuclear magnetic resonance analyses and molecular dynamics simulations revealed that anionic side chains interacted with complementary, regularly spaced cationic amyloid residues of model prions. These findings allowed us to extract structural rules governing the interaction between LCPs and protein aggregates, which we then used to design a new set of LCPs with optimized binding. The new set of LCPs showed robust prophylactic and therapeutic potency in prion-infected mice, with the lead compound extending survival by greater than80% and showing activity against both mouse and hamster prions as well as efficacy upon intraperitoneal administration into mice. These results demonstrate the feasibility of targeted chemical design of compounds that may be useful for treating diseases of aberrant protein aggregation such as prion disease.
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| 14. |
- Hosseini, Hadis, et al.
(författare)
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Nutrient Use in Vertical Farming : Optimal Electrical Conductivity of Nutrient Solution for Growth of Lettuce and Basil in Hydroponic Cultivation
- 2021
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Ingår i: Horticulturae. - : MDPI. - 2311-7524. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- During the past few decades, vertical farming has attracted a lot of interest as an alternative food production method. Vertical farms use engineered growth environments and hydroponic cultivation techniques for growing plants indoors. One of the important factors in vertical farming for the cultivation of different plants is the amount of nutrients, which can be measured as electrical conductivity (EC). Studying the optimal EC is important for avoiding nutrient loss and deficiency in vertical farms. In this study, we investigated the effect of five EC levels (2, 1.2, 0.9, 0.7, and 0.5 dS m(-1)) of Hoagland nutrient solution on the growth and development of basil cultivar Emily and lettuce cultivar Batavia-Caipira. During the study, the environmental parameters were kept fixed using an automatic dosing machine. The experiment was done in automatic vertical farms using the hydroponic ebb-flow cultivation technique with a temperature of 20 +/- 1 degrees C, relative humidity of 50-60%, CO2 concentration of 450 ppm, pH = 6, the PPFD (photosynthetic photon flux density) of 215 +/- 5.5 mu mol m(-2) s(-1), and the photoperiod of 16:8 h (day/night). Each treatment was replicated four times. We studied the effects on several growth parameters (including the dry and fresh weight of leaves and roots, number of leaves, and leaf area) as well as the chlorophyll and nitrogen concentration of the leaves. According to the results, the basil and lettuce growth parameters among the five treatments have been significantly higher in the treatment with EC of 1.2 and 0.9 dS m(-1). These EC values are lower than the recommended EC value given as the optimum in the previous studies. However, the concentration of chlorophyll and nitrogen show different trends and were higher in full strength of nutrient solution with EC = 2 dS m(-1).
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| 15. |
- Janosik, Tomasz, et al.
(författare)
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Efficient sulfonation of 1-phenylsulfonyl-1H-pyrroles and 1-phenylsulfonyl-1H-indoles using chlorosulfonic acid in acetonitrile
- 2006
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Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 62:8, s. 1699-1707
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Tidskriftsartikel (refereegranskat)abstract
- The sulfonation of various 1-phenylsulfonyl-1H-pyrroles and 1-phenylsulfonyl-1H-indoles using chlorosulfonic acid in acetonitrile has been studied, leading to the development of a clean and operationally simple protocol allowing direct synthesis of the corresponding 1-phenylsulfonyl-1H-pyrrole-3-sulfonyl chlorides and 1-phenylsulfonyl-1H-indole-3-sulfonyl chlorides, respectively, both of which may be easily converted to various sulfonamide derivatives by treatment with nitrogen nucleophiles. Efficient and selective removal of the phenylsulfonyl- or tosyl groups in the sulfonamide series may be achieved under mild conditions.
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| 16. |
- Kirschenbaum, Daniel, et al.
(författare)
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Whole-brain microscopy reveals distinct temporal and spatial efficacy of anti-A beta therapies
- 2023
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Ingår i: EMBO Molecular Medicine. - : WILEY. - 1757-4676 .- 1757-4684. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- Many efforts targeting amyloid-beta (A beta) plaques for the treatment of Alzheimers Disease thus far have resulted in failures during clinical trials. Regional and temporal heterogeneity of efficacy and dependence on plaque maturity may have contributed to these disappointing outcomes. In this study, we mapped the regional and temporal specificity of various anti-A beta treatments through high-resolution light-sheet imaging of electrophoretically cleared brains. We assessed the effect on amyloid plaque formation and growth in Thy1-APP/PS1 mice subjected to beta-secretase inhibitors, polythiophenes, or anti-A beta antibodies. Each treatment showed unique spatiotemporal A beta clearance, with polythiophenes emerging as a potent anti-A beta compound. Furthermore, aligning with a spatial-transcriptomic atlas revealed transcripts that correlate with the efficacy of each A beta therapy. As observed in this study, there is a striking dependence of specific treatments on the location and maturity of A beta plaques. This may also contribute to the clinical trial failures of A beta-therapies, suggesting that combinatorial regimens may be significantly more effective in clearing amyloid deposition.
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| 17. |
- Klingstedt, Therése, et al.
(författare)
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Distinct Spacing Between Anionic Groups: An Essential Chemical Determinant for Achieving Thiophene-Based Ligands to Distinguish Beta-Amyloid or Tau Polymorphic Aggregates
- 2015
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlag. - 0947-6539 .- 1521-3765. ; 21:25, s. 9072-9082
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of protein aggregates is associated with many devastating neurodegenerative diseases and the existence of distinct aggregated morphotypes has been suggested to explain the heterogeneous phenotype reported for these diseases. Thus, the development of molecular probes able to distinguish such morphotypes is essential. We report an anionic tetrameric oligothiophene compound that can be utilized for spectral assignment of different morphotypes of -amyloid or tau aggregates present in transgenic mice at distinct ages. The ability of the ligand to spectrally distinguish between the aggregated morphotypes was reduced when the spacing between the anionic substituents along the conjugated thiophene backbone was altered, which verified that specific molecular interactions between the ligand and the protein aggregate are necessary to detect aggregate polymorphism. Our findings provide the structural and functional basis for the development of new fluorescent ligands that can distinguish between different morphotypes of protein aggregates.
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| 18. |
- Klingstedt, Therése, et al.
(författare)
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The structural basis for optimal performance of oligothiophene based fluorescent amyloid ligands : Conformational flexibility is essential for spectral assignment of a diversity of protein aggregates
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Protein misfolding diseases are characterized by deposition of protein aggregates and optical ligands for molecular characterization of these disease-associated structures are important for understanding their potential role in the pathogenesis of the disease. Luminescent conjugated oligothiophenes (LCOs) have proven useful for optical identification of a broader subset of disease-associated protein aggregates than conventional ligands, such as Thioflavin T (ThT) and Congo red. Herein, the molecular requirements for achieving LCOs able to detect non-thioflavinophilic Aβ aggregates or non-congophilic prion aggregates, as well as spectrally discriminate Aβ and tau aggregates, were investigated. An anionic pentameric LCO was subjected to chemical engineering by i) replacing thiophene units with selenophene or phenylene moieties or ii) alternating the anionic substituents along the thiophene backbone. In addition, two asymmetric tetrameric ligands were generated. Overall, the results from this study identified conformational freedom and extended conjugation of the conjugated backbone as crucial determinants for obtaining superior thiophene-based optical ligands for sensitive detection and spectral assignment of diseaseassociated protein aggregates.
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| 19. |
- Klingstedt, Therése, et al.
(författare)
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The Structural Basis for Optimal Performance of Oligothiophene-Based Fluorescent Amyloid Ligands : Conformational Flexibility is Essential for Spectral Assignment of a Diversity of Protein Aggregates
- 2013
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlag. - 0947-6539 .- 1521-3765. ; 19:31, s. 10179-10192
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Tidskriftsartikel (refereegranskat)abstract
- Protein misfolding diseases are characterized by deposition of protein aggregates, and optical ligands for molecular characterization of these disease-associated structures are important for understanding their potential role in the pathogenesis of the disease. Luminescent conjugated oligothiophenes (LCOs) have proven useful for optical identification of a broader subset of disease-associated protein aggregates than conventional ligands, such as thioflavin T and Congo red. Herein, the molecular requirements for achieving LCOs able to detect nonthioflavinophilic Aβ aggregates or non-congophilic prion aggregates, as well as spectrally discriminate Aβ and tau aggregates, were investigated. An anionic pentameric LCO was subjected to chemical engineering by: 1) replacing thiophene units with selenophene or phenylene moieties, or 2) alternating the anionic substituents along the thiophene backbone. In addition, two asymmetric tetrameric ligands were generated. Overall, the results from this study identified conformational freedom and extended conjugation of the conjugated backbone as crucial determinants for obtaining superior thiophene-based optical ligands for sensitive detection and spectral assignment of disease-associated protein aggregates.
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| 20. |
- Klingstedt, Therése, et al.
(författare)
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Thiophene-Based Ligands for Specific Assignment of Distinct Aβ Pathologies in Alzheimer's Disease
- 2024
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Ingår i: ACS CHEMICAL NEUROSCIENCE. - : AMER CHEMICAL SOC. - 1948-7193. ; 15:7, s. 1581-1595
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Tidskriftsartikel (refereegranskat)abstract
- Aggregated species of amyloid-beta (A beta) are one of the pathological hallmarks in Alzheimer's disease (AD), and ligands that selectively target different A beta deposits are of great interest. In this study, fluorescent thiophene-based ligands have been used to illustrate the features of different types of A beta 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 A beta 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 A beta plaques, whereas LL-1 mainly stained cored and neuritic A beta deposits. In the PSEN1 A431E cases, each ligand was binding to specific types of A beta plaques. The ligand-labeled A beta deposits were localized in distinct cortical layers, and a laminar staining pattern could be seen. Biochemical characterization of the A beta aggregates in the individual layers also showed that the variation of ligand binding properties was associated with certain A beta 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 A beta deposits. Overall, our findings showed that a combination of ligands was essential to identify distinct aggregated A beta species associated with different forms of AD.
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| 21. |
- Klingstedt, Therése, et al.
(författare)
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Thiophene-Based Optical Ligands That Selectively Detect A beta Pathology in Alzheimers Disease
- 2021
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Ingår i: ChemBioChem. - : Wiley-V C H Verlag GMBH. - 1439-4227 .- 1439-7633. ; 22:15, s. 2568-2581
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Tidskriftsartikel (refereegranskat)abstract
- In 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-beta (A beta) aggregates in brain tissue from individuals diagnosed neuropathologically as having Alzheimers disease (AD). The selectivity for A beta was dependent on the position of nitrogen in the heterocyclic compounds, and the ability to bind A beta 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 A beta aggregation and for designing molecules for imaging of A beta pathology.
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| 22. |
- Lantz, Linda, et al.
(författare)
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Synthesis and Characterization of Thiophene-based Donor-Acceptor-Donor Heptameric Ligands for Spectral Assignment of Polymorphic Amyloid-beta Deposits
- 2020
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Ingår i: Chemistry - A European Journal. - : WILEY-V C H VERLAG GMBH. - 0947-6539 .- 1521-3765. ; 26:33, s. 7425-7432
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Tidskriftsartikel (refereegranskat)abstract
- Protein deposits are associated with many devastating diseases and fluorescent ligands able to visualize these pathological entities are essential. Here, we report the synthesis of thiophene-based donor-acceptor-donor heptameric ligands that can be utilized for spectral assignment of distinct amyloid-beta (A beta) aggregates, one of the pathological hallmarks in Alzheimers disease. The ability of the ligands to selectively distinguish A beta deposits was abolished when the chemical composition of the ligands was altered. Our findings provide the structural and functional basis for the development of new fluorescent ligands that can distinguish between aggregated proteinaceous species consisting of the same peptide or protein. In addition, such ligands might aid in interpreting the potential role of polymorphic A beta deposits in the pathogenesis of Alzheimers disease.
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| 23. |
- Lantz, Linda, et al.
(författare)
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Thiophene-Based Ligands for Histological Multiplex Spectral Detection of Distinct Protein Aggregates in Alzheimers Disease
- 2023
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Ingår i: Chemistry - A European Journal. - : WILEY-V C H VERLAG GMBH. - 0947-6539 .- 1521-3765.
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Tidskriftsartikel (refereegranskat)abstract
- The 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 Alzheimers disease (AD). The ability of the ligands to selectively identify AD-associated pathological alterations, such as deposits composed of aggregates of the amyloid-beta (A beta) 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.
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| 24. |
- Selegård, Robert, et al.
(författare)
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Distinct Electrostatic Interactions Govern the Chiro-Optical Properties and Architectural Arrangement of Peptide-Oligothiophene Hybrid Materials
- 2017
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Ingår i: Macromolecules. - : AMER CHEMICAL SOC. - 0024-9297 .- 1520-5835. ; 50:18, s. 7102-7110
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Tidskriftsartikel (refereegranskat)abstract
- The development of chiral optoelectronic materials is of great interest due to their potential of being utilized in electronic devices, biosensors, and artificial enzymes. Herein, we report the chiral optical properties and architectural arrangement of optoelectronic materials generated from noncovalent self-assembly of a cationic synthetic peptide and five chemically defined anionic pentameric oligothiophenes. The peptide-oligothiophene hybrid materials exhibit a three-dimensional ordered helical structure and optical activity in the pi-pi* transition region that are observed due to a single chain induced chirality of the conjugated thiophene backbone upon interaction with the peptide. The latter property is highly dependent on electrostatic interactions between the peptide and the oligothiophene, verifying that a distinct spacing of the carboxyl groups along the thiophene backbone is a major chemical determinant for having a hybrid material with distinct optoelectronic properties. The necessity of the electrostatic interaction between specific carboxyl functionalities along the thiophene backbone and the lysine residues of the peptide, as well as the induced circular dichroism of the thiophene backbone, was also confirmed by theoretical calculations. We foresee that our findings will aid in designing optoelectronic materials with dynamic architectonical precisions as well as offer the possibility to create the next generation of materials for organic electronics and organic bioelectronics.
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| 25. |
- Shahnawaz, Mohammad, et al.
(författare)
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Discriminating alpha-synuclein strains in Parkinsons disease and multiple system atrophy
- 2020
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Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 578:7794, s. 273-277
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Tidskriftsartikel (refereegranskat)abstract
- Synucleinopathies are neurodegenerative diseases that are associated with the misfolding and aggregation of alpha-synuclein, including Parkinsons disease, dementia with Lewy bodies and multiple system atrophy(1). Clinically, it is challenging to differentiate Parkinsons disease and multiple system atrophy, especially at the early stages of disease(2). Aggregates of alpha-synuclein in distinct synucleinopathies have been proposed to represent different conformational strains of alpha-synuclein that can self-propagate and spread from cell to cell(3-6). Protein misfolding cyclic amplification (PMCA) is a technique that has previously been used to detect alpha-synuclein aggregates in samples of cerebrospinal fluid with high sensitivity and specificity(7,8). Here we show that the alpha-synuclein-PMCA assay can discriminate between samples of cerebrospinal fluid from patients diagnosed with Parkinsons disease and samples from patients with multiple system atrophy, with an overall sensitivity of 95.4%. We used a combination of biochemical, biophysical and biological methods to analyse the product of alpha-synuclein-PMCA, and found that the characteristics of the alpha-synuclein aggregates in the cerebrospinal fluid could be used to readily distinguish between Parkinsons disease and multiple system atrophy. We also found that the properties of aggregates that were amplified from the cerebrospinal fluid were similar to those of aggregates that were amplified from the brain. These findings suggest that alpha-synuclein aggregates that are associated with Parkinsons disease and multiple system atrophy correspond to different conformational strains of alpha-synuclein, which can be amplified and detected by alpha-synuclein-PMCA. Our results may help to improve our understanding of the mechanism of alpha-synuclein misfolding and the structures of the aggregates that are implicated in different synucleinopathies, and may also enable the development of a biochemical assay to discriminate between Parkinsons disease and multiple system atrophy. Protein misfolding cyclic amplification (PMCA) technology can discriminate between patients with Parkinsons disease and patients with multiple system atrophy on the basis of the characteristics of the alpha-synuclein aggregates in the cerebrospinal fluid.
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| 26. |
- Shirani, Hamid, et al.
(författare)
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A Palette of Fluorescent Thiophene-Based Ligands for the Identification of Protein Aggregates
- 2015
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 21:43, s. 15133-15137
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Tidskriftsartikel (refereegranskat)abstract
- By replacing the central thiophene unit of an anionic pentameric oligothiophene with other heterocyclic moities, a palette of pentameric thiophene-based ligands with distinct fluorescent properties were synthesized. All ligands displayed superior selectivity towards recombinant amyloid fibrils as well as disease-associated protein aggregates in tissue sections.
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| 27. |
- Shirani, Hamid
(författare)
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Application of metalation reactions for synthesis of sulfur/selenium-containing heterocyclic compounds
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals mainly with the synthesis of various sulfur/selenium-containing heterocyclic compounds, many of which include structural features present in several biologically active molecules, with particular emphasis on compounds of synthetic importance, such as indoles, as well as other heteroaromatic species. In the first part, an efficient procedure toward synthesis of new 3-(arylthio)indoles based on reactions of aryl Grignard reagents or lithiated heteroaromatics with protected 3,3′-dithiobisindoles is described. In addition, the heterocyclic core of the marine alkaloid echinosulfone A, namely 3,3′-bis(indolyl) sulfone, was obtained by treatment of a 3-lithioindole derivative with bis(phenylsulfonyl) sulfide. These methodologies offer convenient synthetic routes toward a wide range of 3-(arylthio)indoles in good yields. In an extension, the sulfonation of 1-(phenylsulfonyl)indoles and pyrroles using chlorosulfonic acid in acetonitrile has been studied, leading to development of a simple and clean protocol for synthesis of the corresponding 1-phenylsulfonyl-1H-indole-3-sulfonyl chlorides and 1-phenylsulfonyl-1H-pyrrole-3-sulfonyl chlorides. In the second part, a new practical approach is described toward the synthesis of several biologically active indolothiopyrans and related selenopyrans, as analogues of indolocarbazoles. The target compounds were accessed via treatment of C-2 metalated indoles with bis(phenylsulfonyl) sulfide or selenide, followed by cyclization of the intermediate 2,2′-di(indolyl) sulfide/selenides, involving for example triethyl orthoformate under acidic conditions. The final section of this thesis describes a new method for synthesis of dibenzo[b,f]thiepins and related fused systems via ortho-metalation of aromatic acetals, followed by treatment with bis(phenylsulfonyl) sulfide, initially giving symmetrical diaryl-sulfides, which were subjected to deacetalization, and finally McMurry coupling. The method could also be extended to preparation of thiepin analogues such as 1-sila-, 1-germa- and 1-selenacyclohepta-2,4,6-trienes containing two fused aromatic or heterocyclic units.
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| 28. |
- Shirani, Hamid, et al.
(författare)
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New routes to 3-(Arylthio)indoles : Application to the synthesis of the 3,3 '-bis(indolyl) sulfone core of the marine alkaloid echinosulfone A
- 2006
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Ingår i: Synlett. - : Georg Thieme Verlag KG. - 0936-5214 .- 1437-2096. ; :15, s. 2459-2463
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Tidskriftsartikel (refereegranskat)abstract
- A new approach to 3-(arylthio)indoles and related compounds has been developed, based on the reactions of aryl Grignard reagents or lithiated heteroaroinatics with a phenylsulfonyl-protected 3,3'-bis(indolyl) disulfide. In addition, a rational approach to the 3,3'-bis(indolyl) sulfone core of the alkaloid echinosulfone A has been accomplished, involving treatment of a 3-lithioindole with bis(phenylsulfonyl) sulfide as the key step.
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| 29. |
- Shirani, Hamid, et al.
(författare)
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Synthesis of Thiophene-Based Optical Ligands That Selectively Detect Tau Pathology in Alzheimers Disease
- 2017
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Ingår i: Chemistry - A European Journal. - : WILEY-V C H VERLAG GMBH. - 0947-6539 .- 1521-3765. ; 23:67, s. 17127-17135
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of protein aggregates is associated with many devastating neurodegenerative diseases and the development of molecular ligands able to detect these pathological hallmarks is essential. Here, the synthesis of thiophene based optical ligands, denoted bi-thiophene-vinyl-benzothiazoles (bTVBTs) that can be utilized for selective assignment of tau aggregates in brain tissue with Alzheimers disease (AD) pathology is reported. The ability of the ligands to selectively distinguish tau deposits from the other AD associated pathological hallmark, senile plaques consisting of aggregated amyloid- (A) peptide, was reduced when the chemical composition of the ligands was altered, verifying that specific molecular interactions between the ligands and the aggregates are necessary for the selective detection of tau deposits. Our findings provide the structural and functional basis for the development of new fluorescent ligands that can distinguish between aggregated proteinaceous species consisting of different proteins. In addition, the bTVBT scaffold might be utilized to create powerful practical research tools for studying the underlying molecular events of tau aggregation and for creating novel agents for clinical imaging of tau pathology in AD.
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| 30. |
- Simon, Rozalyn, et al.
(författare)
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Pentameric Thiophene-Based Ligands that Spectrally Discriminate Amyloid-b and Tau Aggregates Display Distinct Solvatochromism and Viscosity-Induced Spectral Shifts
- 2014
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 20:39, s. 12537-12543
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Tidskriftsartikel (refereegranskat)abstract
- A wide range of neurodegenerative diseases are characterized by the deposition of multiple protein aggregates. Ligands for molecular characterization and discrimination of these pathological hallmarks are thus important for understanding their potential role in pathogenesis as well as for clinical diagnosis of the disease. In this regard, luminescent conjugated oligothiophenes (LCOs) have proven useful for spectral discrimination of amyloid-beta (Aβ) and tau neurofibrillary tangles (NFTs), two of the pathological hallmarks associated with Alzheimer’s disease. Herein, the solvatochromism of a library of anionic pentameric thiophene-based ligands, as well as their ability to spectrally discriminate Aβ and tau aggregates, were investigated. Overall, the results from this study identified distinct solvatochromic and viscosity-dependent behavior of thiophene-based ligands that can be applied as indices to direct the chemical design of improved LCOs for spectral separation of Aβ and tau aggregates in brain tissue sections. The results also suggest that the observed spectral transitions of the ligands are due to their ability to conform by induced fit to specific microenvironments within the binding interface of each particular protein aggregate. We foresee that these findings might aid in the chemical design of thiophene-based ligands that are increasingly selective for distinct disease-associated protein aggregates.
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| 31. |
- Simon, Rozalyn, et al.
(författare)
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pH-dependent optical transitions in anionic pentameric oligothiophenes
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Understanding the photo-physical processes in fluorescent probes are essential as such dyes are widely utilized in molecular biology. Here we report the pH-dependent optical transitions of a library of anionic pentameric luminescent conjugated oligothiophenes (LCOs) that have been used for fluorescent identification of protein aggregates, the pathological hallmark of many devastating diseases. Absorption-, excitation- and emission spectra were recorded for all LCOs in different buffers with a pH range from 3.5 to 7. p-FTAA, a LCO having a central core consisting of a trimeric thiophene building block with head-to-head acetic acid functionalization as well as terminal carboxyl groups extending the pentameric thiophene backbone, displayed pH/dependent optical characteristics correlating to a non-planar to planar transition of the conjugated backbone as well as aggregation between adjacent thiophene chain upon protonation of the acetic acid side chains. In contrast, chemically related analogues to p-FTAA lacking the terminal carboxyl groups extending the pentameric thiophene backbone or the conformational ability to undergo a non/planar to planar transition of the conjugated backbone, displayed different optical characteristics compared to p-FTAA. Overall these studies highlighted that minor chemical alteration of LCOs can result in major difference in the optical characteristics obtained from the dyes and the results might aid in designing novel LCOs that have superior optical performance as amyloid ligands.
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| 32. |
- Wahlström, Niklas, 1990-, et al.
(författare)
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Cellulose from the green macroalgae Ulva lactuca: isolation, characterization, optotracing, and production of cellulose nanofibrils
- 2020
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Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X.
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Tidskriftsartikel (refereegranskat)abstract
- We report (1) successful extraction and characterization of cellulose from northern hemisphere green macroalgae Ulva lactuca (Ulva fenestrata) collected along the Swedish west coast and cultivated indoors under controlled conditions, followed by (2) its utilization in the production of lignin-free cellulose nanofibrils (CNF). Cellulose was extracted by sequential treatment with ethanol, hydrogen peroxide, sodium hydroxide, and hydrochloric acid, yielding a cellulose-rich insoluble fraction. The extracted cellulose was disintegrated into CNF using a mechanical homogenization process without any further enzymatic pre-treatments. In addition, regenerated cellulose was prepared. XRD characterization of the CNF showed characteristic peaks for the cellulose I allomorph and confirmed that the nanofibrils were semicrystalline with a crystallinity index of 48%. Regenerated cellulose was mostly amorphous with an XRD pattern indicating the presence of the cellulose II allomorph. The cellulose fractions were essentially free from inorganic substances and thermally stable up to around 260 degrees C. Structural mapping with CP-MAS C-13-NMR sustains the cellulose content of CNF and regenerated cellulose, respectively, yet ion chromatography identified the presence of 10-15% xylose in the fractions. Optotracing was used as a novel and non-disruptive tool to selectively assess the polysaccharide composition of the cellulose fractions and produced CNF aiming to shed light on this hitherto non-resolved origin of xylose in Ulva cell wall matter. Fluorescence excitation and emission spectra of a panel of 4 oligothiophenes identified and verified the presence of cellulose and sustain the conclusion that the isolated fractions consist of cellulose intertwined with a small amount of a xylose-containing glucan copolymer. [GRAPHICS] .
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