The protein alpha-synuclein is predominantly expressed in neurons and is associated with neurodegenerative diseases like Parkinson's disease and dementia with Lewy bodies. However, the normal ...function of alpha-synuclein in neurons is not clearly defined. We have previously shown that mice lacking alpha-synuclein expression exhibit markedly increased viral growth in the brain, increased mortality and increased neuronal cell death, implicating alpha-synuclein in the neuronal innate immune response. To investigate the mechanism of alpha-synuclein-induced immune responses to viral infections in the brain, we challenged alpha-synuclein knockout mice and human alpha-synuclein knockout dopaminergic neurons with RNA virus infection and discovered that alpha-synuclein is required for neuronal expression of interferon-stimulated genes. Furthermore, human alpha-synuclein knockout neurons treated with type 1 interferon failed to induce a broad range of interferon stimulated genes, implying that alpha-synuclein interacts with type 1 interferon signalling. We next found that alpha-synuclein accumulates in the nucleus of interferon-treated human neurons after interferon treatment and we demonstrated that interferon-mediated phosphorylation of STAT2 is dependent on alpha-synuclein expression in human neurons. Next, we found that activated STAT2 co-localizes with alpha-synuclein following type 1 interferon stimulation in neurons. Finally, we found that brain tissue from patients with viral encephalitis expresses increased levels of phospho-serine129 alpha-synuclein in neurons. Taken together, our results show that alpha-synuclein expression supports neuron-specific interferon responses by localizing to the nucleus, supporting STAT2 activation, co-localizing with phosphorylated STAT2 in neurons and supporting expression of interferon-stimulated genes. These data provide a novel mechanism that links interferon activation and alpha-synuclein function in neurons.
DNA double strand breaks (DSB) are repaired by nonhomologous end-joining (NHEJ) or homologous recombination (HR). Recent genetic data in yeast shows that the choice between these two pathways for the ...repair of DSBs is via competition between the NHEJ protein, Ku, and the HR protein, Mre11/Rad50/Xrs2 (MRX) complex. To study the interrelationship between human Ku and Mre11 or Mre11/Rad50 (MR), we established an in vitro DNA end resection system using a forked model dsDNA substrate and purified human Ku70/80, Mre11, Mre11/Rad50, and exonuclease 1 (Exo1). Our study shows that the addition of Ku70/80 blocks Exo1-mediated DNA end resection of the forked dsDNA substrate. Although human Mre11 and MR bind to the forked double strand DNA, they could not compete with Ku for DNA ends or actively mediate the displacement of Ku from the DNA end either physically or via its exonuclease or endonuclease activity. Our in vitro studies show that Ku can block DNA resection and suggest that Ku must be actively displaced for DNA end processing to occur and is more complicated than the competition model established in yeast.
Background: Pathway choice for the repair of double strand breaks is not fully understood.
Results: Human Ku blocks exonuclease 1-mediated DNA processing in the presence of Mre11 or Mre11/Rad50.
Conclusion: Unlike in yeast, the displacement of Ku from DNA ends is not mediated by Mre11 or the Mre11/Rad50 complex.
Significance: Pathway choice between nonhomologous end-joining and homologous recombination is likely more complex than simple competition between the two pathways.
Catheter-associated urinary tract infection (CAUTI) is the commonest hospital-acquired infection, accounting for over 100,000 hospital admissions within the USA annually. Biomaterials and processes ...intended to reduce the risk of bacterial colonization of the catheters for long-term users have not been successful, mainly because of the need for long duration of activity in flow conditions. Here we report the results of impregnation of urinary catheters with a combination of rifampicin, sparfloxacin and triclosan. In flow experiments, the antimicrobial catheters were able to prevent colonization by common uropathogens Proteus mirabilis, Staphylococcus aureus and Escherichia coli for 7 to 12weeks in vitro compared with 1–3days for other, commercially available antimicrobial catheters currently used clinically. Resistance development was minimized by careful choice of antimicrobial combinations. Drug release profiles and distribution in the polymer, and surface analysis were also carried out and the process had no deleterious effect on the mechanical performance of the catheter or its balloon. The antimicrobial catheter therefore offers for the first time a means of reducing infection and its complications in long-term urinary catheter users.
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To address the increasing incidence of gonorrhoea and antimicrobial resistance, we compared the efficacy of Listerine and Biotène mouthwashes for preventing gonorrhoea among men who have sex with men ...(MSM).
The OMEGA trial was a multicentre, parallel-group, double-blind randomised controlled trial among MSM, done at three urban sexual health clinics and one general practice clinic in Australia. Men were eligible if they were diagnosed with oropharyngeal gonorrhoea by nucleic acid amplification test (NAAT) in the previous 30 days or were aged 16–24 years. They were randomly assigned to receive Listerine (intervention) or Biotène (control) via a computer-generated sequence (1:1 ratio, block size of four). Participants, clinicians, data collectors, data analysts, and outcome adjudicators were masked to the interventions after assignment. Participants were instructed to rinse and gargle with 20 mL of mouthwash for 60 s at least once daily for 12 weeks. Oropharyngeal swabs were collected by research nurses every 6 weeks, and participants provided saliva samples every 3 weeks, to be tested for Neisseria gonorrhoeae with NAAT and quantitative PCR. The primary outcome was proportion of MSM diagnosed with oropharyngeal N gonorrhoeae infection at any point over the 12-week period, defined as a positive result for either oropharyngeal swabs or saliva samples by NAAT, and the cumulative incidence of oropharyngeal gonorrhoea at the week 12 visit. A modified intention-to-treat analysis for the primary outcome was done that included men who provided at least one follow-up specimen over the 12-week study period. The trial was registered on the Australian and New Zealand Clinical Trials Registry (ACTRN12616000247471).
Between March 30, 2016, and Oct 26, 2018, 786 MSM were screened and 256 were excluded. 264 MSM were randomly assigned to the Biotène group and 266 to the Listerine group. The analysis population included 227 (86%) men in the Biotène group and 219 (82%) in the Listerine group. Oropharyngeal gonorrhoea was detected in ten (4%) of 227 of MSM in the Biotène group and in 15 (7%) of 219 in the Listerine group (adjusted risk difference 2·5%, 95% CI −1·8 to 6·8). The cumulative incidence of oropharyngeal gonorrhoea at the week 12 visit did not differ between the two mouthwash groups (adjusted risk difference 3·1%, 95% CI −1·4 to 7·7).
Listerine did not reduce the incidence of oropharyngeal gonorrhoea compared with Biotène. However, previous research suggests that mouthwash might reduce the infectivity of oropharyngeal gonorrhoea; therefore, further studies of mouthwash examining its inhibitory effect on N gonorrhoeae are warranted to determine if it has a potential role for the prevention of transmission.
Australian National Health and Medical Research Council.
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) regulate glucose and energy homeostasis. Targeting both pathways with GIP receptor (GIPR) antagonist antibody ...(GIPR-Ab) and GLP-1 receptor (GLP-1R) agonist, by generating GIPR-Ab/GLP-1 bispecific molecules, is an approach for treating obesity and its comorbidities. In mice and monkeys, these molecules reduce body weight (BW) and improve many metabolic parameters. BW loss is greater with GIPR-Ab/GLP-1 than with GIPR-Ab or a control antibody conjugate, suggesting synergistic effects. GIPR-Ab/GLP-1 also reduces the respiratory exchange ratio in DIO mice. Simultaneous receptor binding and rapid receptor internalization by GIPR-Ab/GLP-1 amplify endosomal cAMP production in recombinant cells expressing both receptors. This may explain the efficacy of the bispecific molecules. Overall, our GIPR-Ab/GLP-1 molecules promote BW loss, and they may be used for treating obesity.
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GIPR-Ab/GLP-1 is a bispecific molecule used for the treatment of obesityGIPR-Ab/GLP-1 antagonizes GIPR and agonizes GLP-1R in vitroGIPR-Ab/GLP-1 synergistically reduces body weight and metabolic values in animalsGreater receptor internalization with GIPR-Ab/GLP-1 amplifies endosomal cAMP levels
Lu et al. show that tackling obesity with bispecific molecules that antagonize/agonize GIPR/GLP-1R pathways decreases body weight and metabolic parameters in obese mice and monkeys. Mechanistic studies suggest that such molecules bind to GIPR and GLP-1R simultaneously and trigger receptor internalization, amplifying endosomal cAMP signaling in cells expressing both receptors.
Most TPSs (terpene synthases) contain plasticity residues that are responsible for diversified terpene products and functional evolution, which provide a potential for improving catalytic efficiency. ...Artemisinin, a sesquiterpene lactone from Artemisia annua L., is widely used for malaria treatment and progress has been made in engineering the production of artemisinin or its precursors. In the present paper, we report a new sesquiterpene synthase from A. annua, AaBOS (A. annua α-bisabolol synthase), which has high sequence identity with AaADS (A. annua amorpha-4,11-diene synthase), a key enzyme in artemisinin biosynthesis. Comparative analysis of the two enzymes by domain-swapping and structure-based mutagenesis led to the identification of several plasticity residues, whose alteration changed the product profile of AaBOS to include γ-humulene as the major product. To elucidate the underlying mechanisms, we solved the crystal structures of AaBOS and a γ-humulene-producing AaBOS mutant (termed AaBOS-M2). Among the plasticity residues, position 399, located in the substrate-binding pocket, is crucial for both enzymes. In AaBOS, substitution of threonine for leucine (AaBOSL339T) is required for γ-humulene production; whereas in AaADS, replacing the threonine residue with serine (AaADST399S) resulted in a substantial increase in the activity of amorpha-4,11-diene production, probably as a result of accelerated product release. The present study demonstrates that substitution of plasticity residues has potential for improving catalytic efficiency of the enzyme.
Vagus nerve stimulation (VNS) has been shown to enhance learning and memory, yet the mechanisms behind these enhancements are unknown. Here, we present evidence that epigenetic modulation underlies ...VNS-induced improvements in cognition. We show that VNS enhances novelty preference (NP); alters the hippocampal, cortical, and blood epigenetic transcriptomes; and epigenetically modulates neuronal plasticity and stress-response signaling genes in male Sprague Dawley rats. Brain-behavior analysis revealed structure-specific relationships between NP test performance (NPTP) and epigenetic alterations. In the hippocampus, NPTP correlated with decreased histone deacetylase 11 (HDAC11), a transcriptional repressor enriched in CA1 cells important for memory consolidation. In the cortex, the immediate early gene (IEG) ARC was increased in VNS rats and correlated with transcription of plasticity genes and epigenetic regulators, including HDAC3. For rats engaged in NPTP, ARC correlated with performance. Interestingly, blood ARC transcripts decreased in VNS rats performing NPTP, but increased in VNS-only rats. Because DNA double-strand breaks (DSBs) facilitate transcription of IEGs, we investigated phosphorylated H2A.X (γH2A.X), a histone modification known to colocalize with DSBs. In agreement with reduced cortical stress-response transcription factor NF-κB1, chromatin immunoprecipitation revealed reduced γH2A.X in the ARC promoter. Surprisingly, VNS did not significantly reduce transcription of cortical or hippocampal proinflammatory cytokines. However, TNFRSF11B (osteoprotegerin) correlated with NPTP as well as plasticity, stress-response signaling, and epigenetic regulation transcripts in both hippocampus and cortex. Together, our findings provide the first evidence that VNS induces widespread changes in the cognitive epigenetic landscape and specifically affects epigenetic modulators associated with NPTP, stress-response signaling, memory consolidation, and cortical neural remodeling.
Recent studies have implicated vagus nerve stimulation (VNS) in enhanced learning and memory. However, whereas epigenetic modifications are known to play an important role in memory, the particular mechanisms involved in VNS-enhanced cognition are unknown. In this study, we examined brain and behavior changes in VNS and sham rats performing a multiday novelty preference (NP) task. We found that VNS activated specific histone modifications and DNA methylation changes at important stress-response signaling and plasticity genes. Both cortical and hippocampal plasticity changes were predictive of NP test performance. Our results reveal important epigenetic alterations associated with VNS cognitive improvements, as well as new potential pharmacological targets for enhancing cortical and hippocampal plasticity.
The low intrinsic nonlinearity and low signal latency characteristic of Hollow Core Photonic Bandgap Fibers (HC-PBGFs) have fueled strong interest for data transmission applications. Whereas most ...research to date has looked at improving the optical performance of HC-PBGFs (e.g., reducing the loss, increasing the transmission bandwidth and achieving well-tempered modal properties through the suppression of surface mode resonances). In this study, we address the challenging problem of scaling up the fabrication of these fibers to multi-kilometer lengths-an indispensable step to prove this fiber technology as viable. We report the fabrication of low loss, wide bandwidth HC-PBGFs operating both in the conventional telecoms window (1.55 μm) and in the predicted region of minimum loss (2 μm), in lengths that substantially exceed the state of the art. At 2 μm, we obtained a 3.85 km long fiber with ≈3 dB/km loss and >160 nm wide 3 dB bandwidth. Additionally, we report an HC-PBGF operating at 1.55 μm with a length of just over 11 km, transmission bandwidth in excess of 200 nm and a longitudinally uniform loss of ≈5 dB/km, measured via cutback and an integrated scattering method. We used the latter fiber to demonstrate error-free, low-latency, direct-detection 10 Gb/s transmission across the entire C-Band as well as 20 Gb/s quadrature phase shift keyed transmission. These represent the first demonstrations of data transmission over a length of HC-PBGF exceeding 10 km.
There is mounting evidence regarding the cardiovascular benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP-1 RA) among patients with ...atherosclerotic cardiovascular disease (ASCVD) and type 2 diabetes mellitus (T2DM). There is paucity of data assessing real-world practice patterns for these drug classes. We aimed to assess utilization rates of these drug classes and facility-level variation in their use.
We used the nationwide Veterans Affairs (VA) health care system data set from 1 January 2020 to 31 December 2020 and included patients with established ASCVD and T2DM. Among these patients, we assessed the use of SGLT2i and GLP-1 RA and the facility-level variation in their use. Facility-level variation was computed using median rate ratios (MRR), a measure of likelihood that two random facilities differ in use of SGLT2i and GLP-1 RA in patients with ASCVD and T2DM.
Among 537,980 patients with ASCVD and T2DM across 130 VA facilities, 11.2% of patients received an SGLT2i while 8.0% of patients received a GLP-1 RA. Patients receiving these cardioprotective glucose-lowering drug classes were on average younger and had a higher proportion of non-Hispanic Whites. Overall, median (10th-90th percentile) facility-level rates were 14.92% (9.31-22.50) for SGLT2i and 10.88% (4.44-17.07) for GLP-1 RA. There was significant facility-level variation among SGLT2i use-MRRunadjusted: 1.41 (95% CI 1.35-1.47) and MRRadjusted: 1.55 (95% CI 1.46 -1.63). Similar facility-level variation was observed for use of GLP-1 RA-MRRunadjusted: 1.34 (95% CI 1.29-1.38) and MRRadjusted: 1.78 (95% CI 1.65-1.90).
Overall utilization rates of SGLT2i and GLP-1 RA among eligible patients are low, with significantly higher residual facility-level variation in the use of these drug classes. Our results suggest opportunities to optimize their use to prevent future adverse cardiovascular events among these patients.
The gastrointestinal tract microbiome has been suggested as a potential therapeutic target for metabolic diseases such as obesity and Type 2 diabetes mellitus (T2DM). However, the relationship ...between changes in microbial communities and metabolic disease-phenotypes are still poorly understood. In this study, we used antibiotics with markedly different antibacterial spectra to modulate the gut microbiome in a diet-induced obesity mouse model and then measured relevant biochemical, hormonal and phenotypic biomarkers of obesity and T2DM. Mice fed a high-fat diet were treated with either ceftazidime (a primarily anti-Gram negative bacteria antibiotic) or vancomycin (mainly anti-Gram positive bacteria activity) in an escalating three-dose regimen. We also dosed animals with a well-known prebiotic weight-loss supplement, 10% oligofructose saccharide (10% OFS). Vancomycin treated mice showed little weight change and no improvement in glycemic control while ceftazidime and 10% OFS treatments induced significant weight loss. However, only ceftazidime showed significant, dose dependent improvement in key metabolic variables including glucose, insulin, protein tyrosine tyrosine (PYY) and glucagon-like peptide-1 (GLP-1). Subsequently, we confirmed the positive hyperglycemic control effects of ceftazidime in the Zucker diabetic fatty (ZDF) rat model. Metagenomic DNA sequencing of bacterial 16S rRNA gene regions V1-V3 showed that the microbiomes of ceftazidime dosed mice and rats were enriched for the phylum Firmicutes while 10% OFS treated mice had a greater abundance of Bacteroidetes. We show that specific changes in microbial community composition are associated with obesity and glycemic control phenotypes. More broadly, our study suggests that in vivo modulation of the microbiome warrants further investigation as a potential therapeutic strategy for metabolic diseases.
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