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Abstract Background The unprecedented increase in the older population and ever-increasing incidence of dementia are leading to a “silver tsunami” in upcoming decades. To combat multimorbidity and maintain daily activities, elderly people face a high prevalence of polypharmacy. However, how these medications affect dementia-related pathology, such as Alzheimer’s β-amyloid (Aβ) fibrils formation, remains unknown. In the present study, we aimed to analyze the medication profiles of Alzheimer’s disease (AD; n = 124), mild cognitive impairment (MCI; n = 114), and non-demented (ND; n = 228) patients to identify highly prevalent drugs and to determine the effects of those drugs on Aβ fibrils formation. Methods Study subjects (≥ 65 years) were recruited from an academic geriatric practice that heavily focuses on memory disorders. The disease state was defined based on the score of multiple cognitive assessments. Individual medications for each subject were listed and categorized into 10 major drug classes. Statistical analysis was performed to determine the frequency of individual and collective drug classes, which are expressed as percentages of the respective cohorts. 10 µM monomeric β-amyloid (Aβ) 42 and fibrillar Aβ (fAβ) were incubated for 6–48 h in the presence of 25 µM drugs. fAβ was prepared with a 1:10 ratio of Aβ42 to Aβ40. The amount of Aβ fibrils was monitored using a thioflavin T (Th-T) assay. Neuronal cells (N2A and SHSY-5Y) were treated with 25 µM drugs, and cell death was measured using a lactose dehydrogenase (LDH) assay. Results We noticed a high prevalence (82–90%) of polypharmacy and diverse medication profiles including anti-inflammatory (65–77%), vitamin and mineral (64–72%), anti-cholesterol (33–41%), anti-hypersensitive (35–39%), proton pump inhibitor (23–34%), anti-thyroid (9–21%), anti-diabetic (5–13%), anti-constipation (9–11%), anti-coagulant (10–13%), and anti-insomnia (9–20%) drugs in the three cohorts. Our LDH assay with 18 highly prevalent drug components showed toxic effects of Norvasc, Tylenol, Colace, and Plavix on N2A cells, and of vitamin D and Novasc on SH-SY5Y cells. All these drugs except Colace significantly reduced the amount of Aβ fibril when incubated with Aβ42 for a short period (6 h). However, Lipitor, vitamin D, Levothyroxine, Prilosec, Flomax, and Norvasc prominently reduce the amount of fibrils when incubated with monomeric Aβ42 for a longer period (48 h). Furthermore, our disaggregation study with fAβ showed consistent results for cholecalciferol (vitamin D), omeprazole (Prilosec), clopidogrel hydrogensulfate (Flomax), levothyroxine, and amlodipine (Norvasc). The chemical structures of these four efficient molecules contain polyphenol components, a characteristic feature of the structures of polyphenolic inhibitors of Aβ fibrillation. Conclusion A higher polypharmacy incidence was observed in an elderly population of 228 ND, 114 MCI, and 124 AD patients. We found that several highly recommended drug components, including vitamin D3, Levothyroxine, Prilosec, Flomax, and Norvasc, efficiently reduce the amount of fibrils formed by monomeric Aβ42 and existing preformed Aβ fibrils in vitro. However, only Levothyroxine was able to prevent Aβ-mediated toxicity to SH-SY5Y cells. Our study suggested that these drugs likely function as polyphenolic inhibitors of Aβ.

ADP-ribosyltransferases use NAD.sup.+ to catalyse substrate ADP-ribosylation.sup.1, and thereby regulate cellular pathways or contribute to toxin-mediated pathogenicity of bacteria.sup.2-4. Reversible ADP-ribosylation has traditionally been considered a protein-specific modification.sup.5, but recent in vitro studies have suggested nucleic acids as targets.sup.6-9. Here we present evidence that specific, reversible ADP-ribosylation of DNA on thymidine bases occurs in cellulo through the DarT-DarG toxin-antitoxin system, which is found in a variety of bacteria (including global pathogens such as Mycobacterium tuberculosis, enteropathogenic Escherichia coli and Pseudomonas aeruginosa).sup.10. We report the structure of DarT, which identifies this protein as a diverged member of the PARP family. We provide a set of high-resolution structures of this enzyme in ligand-free and pre- and post-reaction states, which reveals a specialized mechanism of catalysis that includes a key active-site arginine that extends the canonical ADP-ribosyltransferase toolkit. Comparison with PARP-HPF1, a well-established DNA repair protein ADP-ribosylation complex, offers insights into how the DarT class of ADP-ribosyltransferases evolved into specific DNA-modifying enzymes. Together, our structural and mechanistic data provide details of this PARP family member and contribute to a fundamental understanding of the ADP-ribosylation of nucleic acids. We also show that thymine-linked ADP-ribose DNA adducts reversed by DarG antitoxin (functioning as a noncanonical DNA repair factor) are used not only for targeted DNA damage to induce toxicity, but also as a signalling strategy for cellular processes. Using M. tuberculosis as an exemplar, we show that DarT-DarG regulates growth by ADP-ribosylation of DNA at the origin of chromosome replication. Structural and mechanistic data of the ADP-ribosyltransferase DarT demonstrate the role of ADP-ribosylation of DNA by this enzyme in generating toxicity and regulating cellular signalling processes in bacteria., Author(s): Marion Schuller [sup.1] , Rachel E. Butler [sup.2] , Antonio Ariza [sup.1] , Callum Tromans-Coia [sup.1] , Gytis Jankevicius [sup.1] [sup.3] , Tim D. W. Claridge [sup.4] , Sharon [...]

Background Lowe syndrome and Dent-2 disease are caused by mutations in the OCRL gene, which encodes for an inositol 5-phosphatase. The renal phenotype associated with OCRL mutations typically comprises a selective proximal tubulopathy, which can manifest as Fanconi syndrome in the most extreme cases. Methods Here, we report a 12-year-old male with nephrotic-range proteinuria and focal segmental glomerulosclerosis on renal biopsy. As a glomerular pathology was suspected, extensive investigation of tubular function was not performed. Results Surprisingly, whole exome sequencing identified a genetic variant in OCRL (c1467-2A>G) that introduced a novel splice mutation leading to skipping of exon 15. In situ hybridisation of adult human kidney tissue and zebrafish larvae showed OCRL expression in the glomerulus, supporting a role for OCRL in glomerular function. In cultured podocytes, we found that OCRL associated with the linker protein IPIP27A and CD2AP, a protein that is important for maintenance of the podocyte slit diaphragm. Conclusion Taken together, this work suggests a previously under-appreciated role for OCRL in glomerular function and highlights the importance of investigating tubular function in patients with persistent proteinuria., Author(s): Rebecca Preston [sup.1] , Richard W Naylor [sup.1] , Graham Stewart [sup.2] , Agnieszka Bierzynska [sup.3] , Moin A Saleem [sup.3] , Martin Lowe [sup.4] , Rachel Lennon [sup.1] [...]

Gene doping in horses is a threat to the fairness in sport and has serious implications for animal welfare. To investigate the effect of long‐term storage on the detection of AAV in plasma and whole blood, samples from an administration study using an adeno‐associated virus serotype 6 expressing green fluorescence protein (AAV6‐GFP) were stored at −20°C for 8 months before analysis. The AAV vector was detected in stored plasma samples, following the same detection profile as the fresh plasma samples. The stored blood showed lower overall DNA detection but followed the same detection profile as the plasma samples. This study provides confidence that re‐analysing plasma samples and/or analysing a frozen 'B' sample with different matrix such as whole blood after prolonged storage will still result in the detection of gene doping material. [ABSTRACT FROM AUTHOR]

Methane (CH4) dynamics in wetlands are spatially variable and difficult to estimate at ecosystem scales. Patches with different plant functional types (PFT) represent discrete units within wetlands that may help characterize patterns in CH4 variability. We investigate dissolved porewater CH4 concentrations, a representation of net CH4 production and potential source of atmospheric flux, in five wetland patches characterized by a dominant PFT or lack of plants. Using soil, porewater, and plant variables we hypothesized to influence CH4, we used three modeling approaches—Classification and regression tree, AIC model selection, and Structural Equation Modeling—to identify direct and indirect influences on porewater CH4 dynamics. Across all three models, dissolved porewater CO2 concentration was the dominant driver of CH4 concentrations, partly through the influence of PFT patches. Plants in each patch type likely had variable influence on CH4 via root exudates (a substrate for methanogens), capacity to transport gas (both O2 from and CH4 to the atmosphere), and plant litter quality which impacted soil respiration and production of CO2 in the porewater. We attribute the importance of CO2 to the dominant methanogenic pathway we identified, which uses CO2 as a terminal electron acceptor. We propose a mechanistic relationship between PFT patches and porewater CH4 dynamics which, when combined with sources of CH4 loss including methanotrophy, oxidation, or plant‐mediated transport, can provide patch‐scale estimates of CH4 flux. Combining these estimates with the distribution of PFTs can improve ecosystem CH4 flux estimates in heterogenous wetlands and improve global CH4 budgets. Plain Language Summary: Methane is a potent greenhouse gas and understanding what controls methane production from microbes to plant communities can improve our estimates of wetland fluxes and global methane budgets. We propose characterizing methane dynamics in herbaceous wetlands at the scale of plant patches as patches integrate multiple local properties, are generally discrete, and relatively easy to map and measure. To characterize common wetland patch types, we investigate patterns of dissolved methane, soil biogeochemistry, and plant properties in 4 vegetated (submerged vegetation, forb, grass, and sedge) and 1 unvegetated wetland patch types in a temperate, freshwater, herbaceous wetland. We found that methane production differs significantly across patches and is largely correlated with each plant's capacity to transport gas to and from the soil, the quality of plant litter, and the properties of dissolved organic carbon in each patch. This work improves our understanding of how patches uniquely influence methane and by mapping the distribution of these patches we can improve our estimates of wetland methane fluxes. Key Points: Herbaceous plant patches present a unit of measure that can integrate multiples scales controlling wetland methane dynamicsMethane dynamics in the soil are linked to plant‐mediated rhizosphere oxygenation, litter quality, and DOC compositionGrass and sedge functional types seem to modulate methane via different mechanisms, highlighting the importance of using functional type [ABSTRACT FROM AUTHOR]