Synthesis and Antimicrobial Activity of Short Analogues of the Marine Antimicrobial Peptide Turgencin A: Effects of SAR Optimizations, Cys-Cys Cyclization and Lipopeptide Modifications

We have synthesised short analogues of the marine antimicrobial peptide Turgencin A from the colonial Arctic ascidian Synoicum turgens. In this study, we focused on a central, cationic 12-residue Cys-Cys loop region within the sequence. Modified (tryptophan- and arginine-enriched) linear peptides were compared with Cys-Cys cyclic derivatives, and both linear and Cys-cyclic peptides were N-terminally acylated with octanoic acid (C8 ), decanoic acid (C10) or dodecanoic acid (C12). The highest antimicrobial potency was achieved by introducing dodecanoic acid to a cyclic Turgencin A analogue with low intrinsic hydrophobicity, and by introducing octanoic acid to a cyclic analogue displaying a higher intrinsic hydrophobicity. Among all tested synthetic Turgencin A lipopeptide analogues, the most promising candidates regarding both antimicrobial and haemolytic activity were C12-cTurg-1 and C8-cTurg-2. These optimized cyclic lipopeptides displayed minimum inhibitory concentrations of 4 µg/mL against Staphylococcus aureus, Escherichia coli and the fungus Rhodothorula sp. Mode of action studies on bacteria showed a rapid membrane disruption and bactericidal effect of the cyclic lipopeptides. Haemolytic activity against human erythrocytes was low, indicating favorable selective targeting of bacterial cells

Antimicrobial Activity of Short Analogues of the Marine Peptide EeCentrocin 1: Synthesis of Lipopeptides and Head-to-Tail Cyclic Peptides and Mechanism of Action Studies

We have synthesised a series of 12-residue analogues of a previously reported lead peptide (P6) developed from the heavy chain of the marine peptide EeCentrocin 1, isolated from the sea urchin Echinus esculentus. We optimised the lead peptide by increasing its net positive charge, its lipophilicity through N-terminal fatty acid acylation or incorporation of a Trp residue, and by synthesising head-to- tail cyclic peptides under pseudo–high-dilution conditions. All peptides were screened for antimicrobial and antifungal activity, and toxicity was determined against human red blood cells. The two most potent peptide analogues were the linear peptide P6-W6R8 and its head-to-tail cyclic analogue cP6-W6R8 displaying minimum inhibitory concentrations of 0.4–6.6 μM against Gram-positive and Gram-negative bacteria and 6.2–13 μM against fungi. All peptides showed low haemolytic activity except for two of the lipopeptides, in which haemolytic activity correlated with increasing acyl chain length. Mode of action studies using bacterial biosensor strains revealed a membrane disruptive effect of both the linear and the cyclic peptide. Overall, the results of our study demonstrated that relatively simple structural modifications could be successfully employed in the development of potent antimicrobial lead peptides derived from marine natural products

People's interest in brain health testing: Findings from an international, online cross-sectional survey

Brain health entails mental wellbeing and cognitive health in the absence of brain disorders. The past decade has seen an explosion of tests, cognitive and biological, to predict various brain conditions, such as Alzheimer's Disease. In line with these current developments, we investigated people's willingness and reasons to—or not to—take a hypothetical brain health test to learn about risk of developing a brain disease, in a cross-sectional multilanguage online survey. The survey was part of the Global Brain Health Survey, open to the public from 4th June 2019 to 31st August 2020. Respondents were largely recruited via European brain councils and research organizations. 27,590 people responded aged 18 years or older and were predominantly women (71%), middle-aged or older (>40 years; 83%), and highly educated (69%). Responses were analyzed to explore the relationship between demographic variables and responses. Results: We found high public interest in brain health testing: over 91% would definitely or probably take a brain health test and 86% would do so even if it gave information about a disease that cannot be treated or prevented. The main reason for taking a test was the ability to respond if one was found to be at risk of brain disease, such as changing lifestyle, seeking counseling or starting treatment. Higher interest in brain health testing was found in men, respondents with lower education levels and those with poor self-reported cognitive health. Conclusion: High public interest in brain health and brain health testing in certain segments of society, coupled with an increase of commercial tests entering the market, is likely to put pressure on public health systems to inform the public about brain health testing in years to come.publishedVersio

The PTPN22 C1858T gene variant is associated with proinsulin in new-onset type 1 diabetes

<p>Abstract</p> <p>Background</p> <p>The protein tyrosine phosphatase nonreceptor type 2 (<it>PTPN22</it>) has been established as a type 1 diabetes susceptibility gene. A recent study found the C1858T variant of this gene to be associated with lower residual fasting C-peptide levels and poorer glycemic control in patients with type 1 diabetes. We investigated the association of the C1858T variant with residual beta-cell function (as assessed by stimulated C-peptide, proinsulin and insulin dose-adjusted HbA_1c), glycemic control, daily insulin requirements, diabetic ketoacidosis (DKA) and diabetes-related autoantibodies (IA-2A, GADA, ICA, ZnT8Ab) in children during the first year after diagnosis of type 1 diabetes.</p> <p>Methods</p> <p>The C1858T variant was genotyped in an international cohort of children (n = 257 patients) with newly diagnosed type 1 diabetes during 12 months after onset. We investigated the association of this variant with liquid-meal stimulated beta-cell function (proinsulin and C-peptide) and antibody status 1, 6 and 12 months after onset. In addition HbA_1cand daily insulin requirements were determined 1, 3, 6, 9 and 12 months after diagnosis. DKA was defined at disease onset.</p> <p>Results</p> <p>A repeated measurement model of all time points showed the stimulated proinsulin level is significantly higher (22%, p = 0.03) for the T allele carriers the first year after onset. We also found a significant positive association between proinsulin and IA levels (est.: 1.12, p = 0.002), which did not influence the association between <it>PTPN22 </it>and proinsulin (est.: 1.28, p = 0.03).</p> <p>Conclusions</p> <p>The T allele of the C1858T variant is positively associated with proinsulin levels during the first 12 months in newly diagnosed type 1 diabetes children.</p

Fructooligosacharides Reduce Pseudomonas aeruginosa PAO1 Pathogenicity through Distinct Mechanisms

Pseudomonas aeruginosa is ubiquitously present in the environment and acts as an opportunistic pathogen on humans, animals and plants. We report here the effects of the prebiotic polysaccharide inulin and its hydrolysed form FOS on this bacterium. FOS was found to inhibit bacterial growth of strain PAO1, while inulin did not affect growth rate or yield in a significant manner. Inulin stimulated biofilm formation, whereas a dramatic reduction of the biofilm formation was observed in the presence of FOS. Similar opposing effects were observed for bacterial motility, where FOS inhibited the swarming and twitching behaviour whereas inulin caused its stimulation. In co-cultures with eukaryotic cells (macrophages) FOS and, to a lesser extent, inulin reduced the secretion of the inflammatory cytokines IL-6, IL-10 and TNF- a . Western blot experiments indicated that the effects mediated by FOS in macrophages are associated with a decreased activation of the NF- k B pathway. Since FOS and inulin stimulate pathway activation in the absence of bacteria, the FOS mediated effect is likely to be of indirect nature, such as via a reduction of bacterial virulence. Further, this modulatory effect is observed also with the highly virulent ptxS mutated strain. Co-culture experiments of P. aeruginosa with IEC18 eukaryotic cells showed that FOS reduces the concentration of the major virulence factor, exotoxin A, suggesting that this is a possible mechanism for the reduction of pathogenicity. The potential of these compounds as components of antibacterial and anti-inflammatory cocktails is discussed.The authors acknowledge financial support from FEDER funds and Fondo Social Europeo through grants from the Spanish Ministry of Economy and Competitiveness (grants SAF2011-22922, SAF2011-22812) the Andalusian regional government Junta de Andalucía (grant CVI-7335) and the Centre of Networked Biomedical Research on Hepatic and Digestive Diseases (CIBERehd) which is funded by the Carlos III Health Institute and the Ramón Areces Foundation, Spain

Center Size and Glycemic Control: An International Study With 504 Centers From Seven Countries

The variance in glycemic control between different childhood diabetes centers is not fully understood. Although the International Society for Pediatric and Adolescent Diabetes guidelines from 2014 recommended center sizes of more than 150 patients (1), it has not been thoroughly investigated whether glycemic control is associated with center size (2–4). We have data from more than 500 childhood diabetes centers from seven different countries and thereby a unique opportunity to elaborate further on this association. Therefore, this study aims to investigate the relationship between center size and glycemic control in children with type 1 diabetes (T1D). Patient data have been described previously (5). Briefly, the population comprised children with T1D in the age-group 3 months from seven high-income countries during 2013–2014: Austria, Denmark, England, Germany, Norway, Sweden, and Wales. Data were anonymized and obtained from five national registries/audits on children with T1D (Austria and Germany use the same electronic health record and England and Wales have a common National Paediatric Diabetes Audit, while Denmark, Norway, and Sweden have national registries). Mean HbA1c was compared between groups after adjusting for sex, age (<6 years, 6 to <12 years, and 12–18 years), duration of diabetes (<2 years, 2 to <5 years, and ≥5 years), and minority status (yes/no) (HbA1c adj) before and after stratifying for treatment modality (insulin injection/pump). Center size was defined as the number of patients with diabetes reported to be cared for in a center. Center size groupings were 1) <20, 2) 20 to <50, 3) 50 to <100, 4) 100 to <200, and 5) ≥200 patients. In total 54,494 children (48% females) with T1D across 504 centers in seven countries were included in the study. The number of centers per country varied between 14 (Wales) and 219 (Germany). Mean (SD) for age was 12.5 (3.9) years, mean age at T1D onset was 7.5 (4.0) years, and mean T1D duration was 5.0 (3.7) years. A total of 21% of patients had minority status, which varied between 5% (Wales) and 28% (Austria). A total of 38.1% of patients were on pump treatment, and the percentage varied between 25% (England) and 69% (Denmark). National coverage of T1D patients was >95% in all countries, apart from Austria, which had ∼80% data coverage. Included patients had 100% data coverage for all of the following variables: sex, age, diabetes duration, minority status, and HbA1c. Data on treatment modality were not available for 2,428 patients (4.5%); of these, 2,130 were from England and 154 were from Sweden. A total of 23.2% of centers had 200 patients, representing 12.3% of all centers. The distribution of small and large centers in the seven countries varied. England and Sweden had few small centers (34%). HbA1c adj was significantly higher in the centers with 50 patients, in both pen users (P 50 patients managed equally well; therefore, centralizing to very-high-volume diabetes centers may not necessarily be an advantage. Future research should focus on identifying reasons leading to differences in glycemic control in T1D patients cared for in small and large centers, e.g., the lack or presence of an updated multidisciplinary diabetes team