385 research outputs found

    Structural characterization of copper(II) binding to α-Synuclein: Insights into the bioinorganic chemistry of Parkinson's disease

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    The aggregation of α -synuclein (AS) is characteristic of Parkinson’s disease and other neurodegenerative synucleinopathies. We demonstrate here that Cu(II) ions are effective in accelerating AS aggregation at physiologically relevant concentrations without altering the resultant fibrillar structures. By using numerous spectroscopic techniques (absorption, CD, EPR, and NMR), we have located the primary binding for Cu(II) to a specific site in the N terminus, involving His-50 as the anchoring residue and other nitrogen oxygen donor atoms in a square planar or distorted tetragonal geometry. The carboxylate-rich C terminus, originally thought to drive copper binding, is able to coordinate a second Cu(II) equivalent, albeit with a 300-fold reduced affinity. The NMR analysis of AS–Cu(II) complexes reveals the existence of conformational restrictions in the native state of the protein. The metallobiology of Cu(II) in Parkinson’s disease is discussed by a comparative analysis with other Cu(II)-binding proteins involved in neurodegenerative disorders

    Enhanced antiviral function of magnesium chloride-modified Heparin on a broad spectrum of viruses

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    Previous studies reported on the broad-spectrum antiviral function of heparin. Here we investigated the antiviral function of magnesium-modified heparin and found that modified heparin displayed a significantly enhanced antiviral function against human adenovirus (HAdV) in immortalized and primary cells. Nuclear magnetic resonance analyses revealed a conformational change of heparin when complexed with magnesium. To broadly explore this discovery, we tested the antiviral function of modified heparin against herpes simplex virus type 1 (HSV-1) and found that the replication of HSV-1 was even further decreased compared to aciclovir. Moreover, we investigated the antiviral effect against the new severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and measured a 55-fold decreased viral load in the supernatant of infected cells associated with a 38-fold decrease in virus growth. The advantage of our modified heparin is an increased antiviral effect compared to regular heparin

    Reducing tau aggregates with anle138b delays disease progression in a mouse model of tauopathies.

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    Pathological tau aggregation leads to filamentous tau inclusions and characterizes neurodegenerative tauopathies such as Alzheimer's disease and frontotemporal dementia and parkinsonism linked to chromosome 17. Tau aggregation coincides with clinical symptoms and is thought to mediate neurodegeneration. Transgenic mice overexpressing mutant human P301S tau exhibit many neuropathological features of human tauopathies including behavioral deficits and increased mortality. Here, we show that the di-phenyl-pyrazole anle138b binds to aggregated tau and inhibits tau aggregation in vitro and in vivo. Furthermore, anle138b treatment effectively ameliorates disease symptoms, increases survival time and improves cognition of tau transgenic PS19 mice. In addition, we found decreased synapse and neuron loss accompanied by a decreased gliosis in the hippocampus. Our results suggest that reducing tau aggregates with anle138b may represent an effective and promising approach for the treatment of human tauopathies

    Brigatinib Versus Crizotinib in ALK Inhibitor–Naive Advanced ALK-Positive NSCLC: Final Results of Phase 3 ALTA-1L Trial

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    Introduction: In the phase 3 study entitled ALK in Lung cancer Trial of brigAtinib in 1st Line (ALTA-1L), which is a study of brigatinib in ALK inhibitor–naive advanced ALK-positive NSCLC, brigatinib exhibited superior progression-free survival (PFS) versus crizotinib in the two planned interim analyses. Here, we report the final efficacy, safety, and exploratory results. Methods: Patients were randomized to brigatinib 180 mg once daily (7-d lead-in at 90 mg once daily) or crizotinib 250 mg twice daily. The primary end point was a blinded independent review committee–assessed PFS. Genetic alterations in plasma cell-free DNA were assessed in relation to clinical efficacy. Results: A total of 275 patients were enrolled (brigatinib, n = 137; crizotinib, n = 138). At study end, (brigatinib median follow-up = 40.4 mo), the 3-year PFS by blinded independent review committee was 43% (brigatinib) versus 19% (crizotinib; median = 24.0 versus 11.1 mo, hazard ratio [HR] = 0.48, 95% confidence interval [CI]: 0.35–0.66). The median overall survival was not reached in either group (HR = 0.81, 95% CI: 0.53–1.22). Posthoc analyses suggested an overall survival benefit for brigatinib in patients with baseline brain metastases (HR = 0.43, 95% CI: 0.21–0.89). Detectable baseline EML4-ALK fusion variant 3 and TP53 mutation in plasma were associated with poor PFS. Brigatinib exhibited superior efficacy compared with crizotinib regardless of EML4-ALK variant and TP53 mutation. Emerging secondary ALK mutations were rare in patients progressing on brigatinib. No new safety signals were observed. Conclusions: In the ALTA-1L final analysis, with longer follow-up, brigatinib continued to exhibit superior efficacy and tolerability versus crizotinib in patients with or without poor prognostic biomarkers. The suggested survival benefit with brigatinib in patients with brain metastases warrants future study

    A Compact Multiphoton 3D Imaging System for Recording Fast Neuronal Activity

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    We constructed a simple and compact imaging system designed specifically for the recording of fast neuronal activity in a 3D volume. The system uses an Yb:KYW femtosecond laser we designed for use with acousto-optic deflection. An integrated two-axis acousto-optic deflector, driven by digitally synthesized signals, can target locations in three dimensions. Data acquisition and the control of scanning are performed by a LeCroy digital oscilloscope. The total cost of construction was one order of magnitude lower than that of a typical Ti:sapphire system. The entire imaging apparatus, including the laser, fits comfortably onto a small rig for electrophysiology. Despite the low cost and simplicity, the convergence of several new technologies allowed us to achieve the following capabilities: i) full-frame acquisition at video rates suitable for patch clamping; ii) random access in under ten microseconds with dwelling ability in the nominal focal plane; iii) three-dimensional random access with the ability to perform fast volume sweeps at kilohertz rates; and iv) fluorescence lifetime imaging. We demonstrate the ability to record action potentials with high temporal resolution using intracellularly loaded potentiometric dye di-2-ANEPEQ. Our design proffers easy integration with electrophysiology and promises a more widespread adoption of functional two-photon imaging as a tool for the study of neuronal activity. The software and firmware we developed is available for download at http://neurospy.org/ under an open source license
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