GPU, Graphics Processing Unit

  • 文章类型: Journal Article
    计算机辅助方法的使用继续推动各种疾病模型加速药物发现,有趣的是,允许特异性抑制致病靶标。氯化物细胞内通道蛋白4(CLIC4)是一类与肿瘤和血管生物学密切相关的新型细胞内离子通道。它调节细胞增殖,细胞凋亡和血管生成;并参与多种病理信号通路。然而,缺乏特异性抑制剂阻碍了其向转化研究的发展。这里,我们整合了结构生物信息学和实验研究方法,以发现和验证CLIC4的小分子抑制剂.通过高性能计算驱动的盲对接方法,从1615个食品和药物管理局(FDA)批准的药物库中鉴定出高亲和力变构结合剂,导致选择两性霉素B和雷帕霉素。NMR测定证实了两种药物的结合和构象破坏作用,同时它们还逆转了应激诱导的CLIC4的膜易位并抑制了内皮细胞迁移。结构和动力学模拟研究进一步表明,这些化合物的抑制机制取决于催化谷胱甘肽(GSH)样位点环和延伸的催化β环的变构调节,这可能引起对CLIC4催化活性的干扰。来自本研究的基于结构的见解为CLIC4的选择性靶向治疗相关病理提供了基础。
    The use of computer-aided methods have continued to propel accelerated drug discovery across various disease models, interestingly allowing the specific inhibition of pathogenic targets. Chloride Intracellular Channel Protein 4 (CLIC4) is a novel class of intracellular ion channel highly implicated in tumor and vascular biology. It regulates cell proliferation, apoptosis and angiogenesis; and is involved in multiple pathologic signaling pathways. Absence of specific inhibitors however impedes its advancement to translational research. Here, we integrate structural bioinformatics and experimental research approaches for the discovery and validation of small-molecule inhibitors of CLIC4. High-affinity allosteric binders were identified from a library of 1615 Food and Drug Administration (FDA)-approved drugs via a high-performance computing-powered blind-docking approach, resulting in the selection of amphotericin B and rapamycin. NMR assays confirmed the binding and conformational disruptive effects of both drugs while they also reversed stress-induced membrane translocation of CLIC4 and inhibited endothelial cell migration. Structural and dynamics simulation studies further revealed that the inhibitory mechanisms of these compounds were hinged on the allosteric modulation of the catalytic glutathione (GSH)-like site loop and the extended catalytic β loop which may elicit interference with the catalytic activities of CLIC4. Structure-based insights from this study provide the basis for the selective targeting of CLIC4 to treat the associated pathologies.
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  • 文章类型: Journal Article
    紧密连接蛋白(Cldns)定义了跨膜蛋白家族,它们是紧密连接完整性和组织选择性的主要决定因素。它们促进在两个面对的细胞之间的界面处形成屏障或离子选择性通道,穿过细胞旁空间。多个Cldn亚基形成复合物,其包括沿着单个细胞的膜的顺式(细胞内)相互作用和跨相邻细胞的跨(细胞间)相互作用。Cldn组件的第一个描述是通过电子显微镜提供的,而电生理学,诱变和细胞生物学实验解决了不同Cldn同源物的功能作用。然而,Cldn亚基和复合物的分子细节的研究受到缺乏实验天然结构的阻碍,目前仅限于Cldn15。基于计算机的技术的最新实现极大地促进了Cldn属性的阐明。分子动力学模拟和对接计算被广泛用于完善从Cldn15的晶体结构假设的第一个Cldn多聚体模型,并有助于引入新的,另类,安排。虽然发现这两种多聚体组件都可以解释某些家族成员的生理特性,他们为他人提供了相互矛盾的结果。在这次审查中,我们说明了通过使用最先进的计算方法实现的基于Cldn的系统的主要发现。这些结果提供的信息可能有助于改善Cldn特性的表征,并有助于设计新的有效策略来控制药物或其他分子的细胞旁转运。
    Claudins (Cldns) define a family of transmembrane proteins that are the major determinants of the tight junction integrity and tissue selectivity. They promote the formation of either barriers or ion-selective channels at the interface between two facing cells, across the paracellular space. Multiple Cldn subunits form complexes that include cis- (intracellular) interactions along the membrane of a single cell and trans- (intercellular) interactions across adjacent cells. The first description of Cldn assemblies was provided by electron microscopy, while electrophysiology, mutagenesis and cell biology experiments addressed the functional role of different Cldn homologs. However, the investigation of the molecular details of Cldn subunits and complexes are hampered by the lack of experimental native structures, currently limited to Cldn15. The recent implementation of computer-based techniques greatly contributed to the elucidation of Cldn properties. Molecular dynamics simulations and docking calculations were extensively used to refine the first Cldn multimeric model postulated from the crystal structure of Cldn15, and contributed to the introduction of a novel, alternative, arrangement. While both these multimeric assemblies were found to account for the physiological properties of some family members, they gave conflicting results for others. In this review, we illustrate the major findings on Cldn-based systems that were achieved by using state-of-the-art computational methodologies. The information provided by these results could be useful to improve the characterization of the Cldn properties and help the design of new efficient strategies to control the paracellular transport of drugs or other molecules.
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  • 文章类型: Journal Article
    一些驱虫药的疗效不佳以及对广泛耐药性的担忧日益增加,这突显了发现新药的必要性。变形线虫是一种重要的模式生物,广泛用于耐药性研究和药物筛选,目前的金标准是运动试验。我们应用了一种深度学习方法MaskR-CNN来分析包含不同速率的活动蠕虫的运动性视频,并将其与其他具有不同复杂程度的常用算法进行了比较。即Wiggle指数和宽视场线虫跟踪平台。MaskR-CNN在蠕虫的检测以及运动性预测的精度方面始终优于其他算法,检测和运动预测的平均绝对百分比误差为7.6%,平均绝对误差为5.6%,分别。使用MaskR-CNN进行运动性分析,证实了在检测重叠物体时使用非最大抑制的算法的常见问题。这会对整体精度产生负面影响。使用交叉联合作为衡量活动/非活动实例分类的总体准确率为89%,表明它是基于运动特征的先前使用的方法的可行替代方案,如身体弯曲。与此处评估的现有方法相比,MaskR-CNN表现更好,我们预计这种方法将扩大蠕虫运动视频分析的可能方法的数量。
    Poor efficacy of some anthelmintics and rising concerns about the widespread drug resistance have highlighted the need for new drug discovery. The parasitic nematode Haemonchus contortus is an important model organism widely used for studies of drug resistance and drug screening with the current gold standard being the motility assay. We applied a deep learning approach Mask R-CNN for analysing motility videos containing varying rates of motile worms and compared it to other commonly used algorithms with different levels of complexity, namely the Wiggle Index and the Wide Field-of-View Nematode Tracking Platform. Mask R-CNN consistently outperformed the other algorithms in terms of the detection of worms as well as the precision of motility forecasts, having a mean absolute percentage error of 7.6% and a mean absolute error of 5.6% for the detection and motility forecasts, respectively. Using Mask R-CNN for motility assays confirmed the common problem with algorithms that use non-maximum suppression in detecting overlapping objects, which negatively impacts the overall precision. The use of intersect over union as a measure of the classification of motile / non-motile instances had an overall accuracy of 89%, indicating that it is a viable alternative to previously used methods based on movement characteristics, such as body bends. In comparison to the existing methods evaluated here, Mask R-CNN performed better and we anticipate that this method will broaden the number of possible approaches to video analysis of worm motility.
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  • 文章类型: Journal Article
    UNASSIGNED: Both Hip Dysplasia(DDH) and Femoro-acetabular-Impingement(FAI) are complex three-dimensional hip pathologies causing hip pain and osteoarthritis in young patients. 3D-MRI-based models were used for radiation-free computer-assisted surgical planning. Automatic segmentation of MRI-based 3D-models are preferred because manual segmentation is time-consuming.To investigate(1) the difference and(2) the correlation for femoral head coverage(FHC) between automatic MR-based and manual CT-based 3D-models and (3) feasibility of preoperative planning in symptomatic patients with hip diseases.
    UNASSIGNED: We performed an IRB-approved comparative, retrospective study of 31 hips(26 symptomatic patients with hip dysplasia or FAI). 3D MRI sequences and CT scans of the hip were acquired. Preoperative MRI included axial-oblique T1 VIBE sequence(0.8 mm3 isovoxel) of the hip joint. Manual segmentation of MRI and CT scans were performed. Automatic segmentation of MRI-based 3D-models was performed using deep learning.
    UNASSIGNED: (1)The difference between automatic and manual segmentation of MRI-based 3D hip joint models was below 1 mm(proximal femur 0.2 ± 0.1 mm and acetabulum 0.3 ± 0.5 mm). Dice coefficients of the proximal femur and the acetabulum were 98 % and 97 %, respectively. (2)The correlation for total FHC was excellent and significant(r = 0.975, p < 0.001) between automatic MRI-based and manual CT-based 3D-models. Correlation for total FHC (r = 0.979, p < 0.001) between automatic and manual MR-based 3D models was excellent.(3)Preoperative planning and simulation of periacetabular osteotomy was feasible in all patients(100 %) with hip dysplasia or acetabular retroversion.
    UNASSIGNED: Automatic segmentation of MRI-based 3D-models using deep learning is as accurate as CT-based 3D-models for patients with hip diseases of childbearing age. This allows radiation-free and patient-specific preoperative simulation and surgical planning of periacetabular osteotomy for patients with DDH.
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