| 1. |
- Bhattacharjee, Payel, 1984, et al.
(författare)
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Aristolochic acid and its derivatives as inhibitors of snake venom L-amino acid oxidase
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 138, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Snake venom L-amino acid oxidase (LAAO) exerts toxicity by inducing hemorrhage, pneumorrhagia, pulmonary edema, cardiac edema, liver cell necrosis etc. Being well conserved, inhibitors of the enzyme may be synthesized using the template of the substrate, substrate binding site and features of the catalytic site of the enzyme. Previous findings showed that aristolochic acid (AA), a major constituent of Aristolochia indica, inhibits Russell's viper venom LAAO enzyme activity since, AA interacts with DNA and causes genotoxicity, derivatives of this compound were synthesized by replacing the nitro group to reduce toxicity while retaining the inhibitory potency. The interactions of AA and its derivatives with LAAO were followed by inhibition kinetics and surface plasmon resonance. Similar interactions with DNA were followed by absorption spectroscopy and atomic force microscopy. LAAO-induced cytotoxicity was evaluated by generation of reactive oxygen species (ROS), cell viability assays, confocal and epifluorescence microscopy. The hydroxyl (AA-OH) and chloro (AA-C1) derivatives acted as inhibitors of LAAO but did not interact with DNA. The derivatives significantly reduced LAAO-induced ROS generation and cytotoxicity in human embryonic kidney (HER 293) and hepatoma (HepG2) cell lines. Confocal images indicated that AA, AA-OH and AA-Cl interfered with the binding of LAAO to the cell membrane. AA-OH and AA-CI significantly inhibited LAAO activity and reduced LAAO-induced cytotoxicity. (C) 2017 Elsevier Ltd. All rights reserved.
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| 2. |
- Bhattacharjee, Payel, 1984, et al.
(författare)
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Mass Spectrometric Analysis of Lewy Body-Enriched alpha-Synuclein in Parkinson's Disease
- 2019
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 18:5, s. 2109-2120
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease (PD) is characterized by intraneuronal inclusions of aggregated alpha-synuclein protein (so-called Lewy bodies) in distinct brain regions. Multiple posttranslational modifications may affect the structure and function of alpha-synuclein. Mass spectrometry-based analysis may be useful for the characterization and quantitation of alpha-synuclein forms, but has proven challenging, mainly due to the insolubility of Lewy bodies in aqueous buffer. In the present study, we developed a novel method by combining differential solubilization with immunoprecipitation and targeted proteomics using liquid chromatography and tandem mass spectrometry. Brain tissue homogenization and sample preparation were modified to facilitate analysis of soluble, detergent-soluble, and detergent-insoluble protein fractions (Lewy body-enriched). The method was used to compare alpha-synuclein forms from cingulate cortex (affected) and occipital cortex (unaffected) in two study sets of PD patients and controls. We identified similar to 20 modified alpha-synuclein variants, including species with N-terminal acetylation and C-terminal truncations at amino acids 103 and 119. The levels of alpha-synuclein forms Ac-alpha-syn(1-6), alpha-syn(13-21), alpha-syn(35-43), alpha-syn(46-58), alpha-syn(61-80), and alpha-syn(81-96) except alpha-syn(103-119) were significantly increased in PD cingulate region compared to controls in the Lewy body-enriched alpha-synuclein fraction. In the soluble fraction, only Ac-alpha-syn(1-6) was significantly increased in PD compared to controls. None of the detected alpha-synuclein variants were Lewy body-specific, but acetylated forms should be examined further as potential biomarkers for abnormal alpha-synuclein accumulation.
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| 3. |
- Brinkmalm, Ann, et al.
(författare)
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Detection of α-Synuclein in Biological Samples Using Mass Spectrometry
- 2019
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Ingår i: Methods in molecular biology (Clifton, N.J.). - New York, NY : Springer. - 1940-6029. ; , s. 209-220
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Bokkapitel (refereegranskat)abstract
- Here we describe a method using mass spectrometry to characterize and quantify immuno-enriched α-synuclein forms from biochemically fractionated brain tissue.
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| 4. |
- Rodrigues, M., et al.
(författare)
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Structure-specific amyloid precipitation in biofluids
- 2022
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Ingår i: Nature Chemistry. - : Springer Science and Business Media LLC. - 1755-4330 .- 1755-4349. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The composition of soluble toxic protein aggregates formed in vivo is currently unknown in neurodegenerative diseases, due to their ultra-low concentration in human biofluids and their high degree of heterogeneity. Here we report a method to capture amyloid-containing aggregates in human biofluids in an unbiased way, a process we name amyloid precipitation. We use a structure-specific chemical dimer, a Y-shaped, bio-inspired small molecule with two capture groups, for amyloid precipitation to increase affinity. Our capture molecule for amyloid precipitation (CAP-1) consists of a derivative of Pittsburgh Compound B (dimer) to target the cross beta-sheets of amyloids and a biotin moiety for surface immobilization. By coupling CAP-1 to magnetic beads, we demonstrate that we can target the amyloid structure of all protein aggregates present in human cerebrospinal fluid, isolate them for analysis and then characterize them using single-molecule fluorescence imaging and mass spectrometry. Amyloid precipitation enables unbiased determination of the molecular composition and structural features of the in vivo aggregates formed in neurodegenerative diseases.
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