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- Gu, Gucci Jijuan, 1984-, et al.
(författare)
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Elevated MARK2-Dependent Phosphorylation of Tau in Alzheimer's Disease
- 2013
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 33:3, s. 699-713
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Tidskriftsartikel (refereegranskat)abstract
- The appearance of neurofibrillary tangles (NFT), one of the major hallmarks of Alzheimer's disease (AD), is most likely caused by inappropriate phosphorylation and/or dephosphorylation of tau, eventually leading to the accumulation of NFTs. Enhanced phosphorylation of tau on Ser(262) is detected early in the course of the disease and may have a role in the formation of tangles. Several kinases such as microtubule-affinity regulating kinase (MARK), protein kinase A, calcium calmodulin kinase II, and checkpoint kinase 2 are known to phosphorylate tau on Ser(262) in vitro. In this study, we took advantage of the in situ proximity ligation assay to investigate the role of MARK2, one of the four MARK isoforms, in AD. We demonstrate that MARK2 interacts with tau and phosphorylates tau at Ser(262) in stably transfected NIH/3T3 cells expressing human recombinant tau. Staurosporine, a protein kinase inhibitor, significantly reduced the interaction between MARK2 and tau, and also phosphorylation of tau at Ser(262). Furthermore, we observed elevated interactions between MARK2 and tau in post-mortem human AD brains, compared to samples from non-demented elderly controls. Our results from transfected cells demonstrate a specific interaction between MARK2 and tau, as well as MARK2-dependent phosphorylation of tau at Ser(262). Furthermore, the elevated interactions between MARK2 and tau in AD brain sections suggests that MARK2 may play an important role in early phosphorylation of tau in AD, possibly qualifying as a therapeutic target for intervention to prevent disease progression.
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- Kaur, Amanpreet, et al.
(författare)
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Chemoselective bicyclobutane-based mass spectrometric detection of biological thiols uncovers human and bacterial metabolites
- 2023
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 14:20, s. 5291-5301
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur is an essential element of life. Thiol-containing metabolites in all organisms are involved in the regulation of diverse biological processes. Especially, the microbiome produces bioactive metabolites or biological intermediates of this compound class. The analysis of thiol-containing metabolites is challenging due to the lack of specific tools, making these compounds difficult to investigate selectively. We have now developed a new methodology comprising bicyclobutane for chemoselective and irreversible capturing of this metabolite class. We utilized this new chemical biology tool immobilized onto magnetic beads for the investigation of human plasma, fecal samples, and bacterial cultures. Our mass spectrometric investigation detected a broad range of human, dietary and bacterial thiol-containing metabolites and we even captured the reactive sulfur species cysteine persulfide in both fecal and bacterial samples. The described comprehensive methodology represents a new mass spectrometric strategy for the discovery of bioactive thiol-containing metabolites in humans and the microbiome.
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- Wang, Xuying, et al.
(författare)
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Analytical survey of tattoo inks – a chemical and legal perspective with focus on sensitizing substances
- 2021
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Ingår i: Contact Dermatitis. - : John Wiley & Sons. - 0105-1873 .- 1600-0536. ; 85, s. 340-353
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tattoo inks have been reported to elicit allergic contact dermatitis.Objectives: To investigate the labels and the contents of metals and pigments in tattoo inks, considering restrictions within the European Union.Methods: 73 tattoo inks currently available on the market, either bought or donated (already used), were investigated for trace metals and pigments by inductively coupled plasma mass spectrometry and by matrix assisted laser desorption/ionization time of flight tandem mass spectrometry.Results: 93% of the bought tattoo inks violated European legal requirements on labeling. 50% of the tattoo inks declared at least one pigment ingredient wrongly. 61% inks contained pigments of concern, especially for red inks. Iron, aluminium, titanium, and copper (most in green/blue inks) were the main metals detected in the inks. The level of metal impurities was only in a few cases exceeding current restriction limits. Total chromium (0.35-139 µg/g) and nickel (0.1-41 µg/g) were found in almost all samples. The levels of iron, chromium, manganese, cobalt, nickel, zinc, lead, and arsenic were found to significantly covary.Conclusions: It is important for tattoo ink manufacturers to follow the regulations and decrease nickel and chromium impurities, to prevent contact allergy and toxic reactions among the users.
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