Generation and Study of Antibodies against Two Triangular Trimers Derived from Aß.

Monoclonal antibodies (mAbs) that target the P-amyloid peptide (Aß) are important Alzheimer's disease research tools and are now being used as Alzheimer's disease therapies. Conformation-specific mAbs that target oligomeric and fibrillar Aß assemblies are of particular interest, as these assemblies are associated with Alzheimer's disease pathogenesis and progression. This paper reports the generation of rabbit mAbs against two different triangular trimers derived from Aß. These antibodies are the first mAbs generated against Aß oligomer mimics in which the high-resolution structures of the oligomers are known. We describe the isolation of the mAbs using single B-cell sorting of peripheral blood mononuclear cells (PBMCs) from immunized rabbits, the selectivity of the mAbs for the triangular trimers, the immunoreactivity of the mAbs with aggregated Aß42, and the immunoreactivity of the mAbs in brain tissue from the 5xFAD Alzheimer's disease mouse model. The characterization of these mAbs against structurally defined trimers derived from Aß enhances understanding of antibody-amyloid recognition and may benefit the development of diagnostics and immunotherapies in Alzheimer's disease.

Antibodies Raised Against an Aß Oligomer Mimic Recognize Pathological Features in Alzheimer's Disease and Associated Amyloid-Disease Brain Tissue.

Antibodies that target the ß-amyloid peptide (Aß) and its associated assemblies are important tools in Alzheimer's disease research and have emerged as promising Alzheimer's disease therapies. This paper reports the creation and characterization of a triangular Aß trimer mimic composed of Aß17-36 ß-hairpins and the generation and study of polyclonal antibodies raised against the Aß trimer mimic. The Aß trimer mimic is covalently stabilized by three disulfide bonds at the corners of the triangular trimer to create a homogeneous oligomer. Structural, biophysical, and cell-based studies demonstrate that the Aß trimer mimic shares characteristics with oligomers of full-length Aß. X-ray crystallography elucidates the structure of the trimer and reveals that four copies of the trimer assemble to form a dodecamer. SDS-PAGE, size exclusion chromatography, and dynamic light scattering reveal that the trimer also forms higher-order assemblies in solution. Cell-based toxicity assays show that the trimer elicits LDH release, decreases ATP levels, and activates caspase-3/7 mediated apoptosis. Immunostaining studies on brain slices from people who lived with Alzheimer's disease and people who lived with Down syndrome reveal that the polyclonal antibodies raised against the Aß trimer mimic recognize pathological features including different types of Aß plaques and cerebral amyloid angiopathy.

Probing differences among Aß oligomers with two triangular trimers derived from Aß.

The assembly of the ß-amyloid peptide (Aß) to form oligomers and fibrils is closely associated with the pathogenesis and progression of Alzheimer's disease. Aß is a shape-shifting peptide capable of adopting many conformations and folds within the multitude of oligomers and fibrils the peptide forms. These properties have precluded detailed structural elucidation and biological characterization of homogeneous, well-defined Aß oligomers. In this paper, we compare the structural, biophysical, and biological characteristics of two different covalently stabilized isomorphic trimers derived from the central and C-terminal regions Aß. X-ray crystallography reveals the structures of the trimers and shows that each trimer forms a ball-shaped dodecamer. Solution-phase and cell-based studies demonstrate that the two trimers exhibit markedly different assembly and biological properties. One trimer forms small soluble oligomers that enter cells through endocytosis and activate capase-3/7-mediated apoptosis, while the other trimer forms large insoluble aggregates that accumulate on the outer plasma membrane and elicit cellular toxicity through an apoptosis-independent mechanism. The two trimers also exhibit different effects on the aggregation, toxicity, and cellular interaction of full-length Aß, with one trimer showing a greater propensity to interact with Aß than the other. The studies described in this paper indicate that the two trimers share structural, biophysical, and biological characteristics with oligomers of full-length Aß. The varying structural, assembly, and biological characteristics of the two trimers provide a working model for how different Aß trimers can assemble and lead to different biological effects, which may help shed light on the differences among Aß oligomers.

Current Peptide Vaccine and Immunotherapy Approaches Against Alzheimer's Disease.

Peptide vaccines and immunotherapies against aggregating proteins involved in the pathogenesis and progression of Alzheimer's disease (AD) - the ß-amyloid peptide (Aß) and tau - are promising therapeutic avenues against AD. Two decades of effort has led to the controversial FDA approval of the monoclonal antibody Aducanumab (Aduhelm), which has subsequentially sparked the revival and expedited review of promising monoclonal antibody immunotherapies that target Aß. In this review, we explore the development of Aß and tau peptide vaccines and immunotherapies with monoclonal antibodies in clinical trials against AD.

Midwives' experiences with screening for intimate partner violence in Santiago, Chile.

Although intimate partner violence (IPV) is well-established as a highly prevalent global issue, research examining the experience of health providers who screen women at risk for IPV is scarce. We aimed to explore the experience of midwives in primary health care centers in Santiago, Chile, regarding identification of at-risk women and barriers to screening. We highlight the intersection of complex issues of global relevance, such as culture, language, provider-patient relationships, and allocation of time and resources. In our results, we illustrate the importance of providing midwives extended time, interpreter services, and cross-cultural education to address IPV in their transcultural context.

Virus-encoded histone doublets are essential and form nucleosome-like structures.

The organization of genomic DNA into defined nucleosomes has long been viewed as a hallmark of eukaryotes. This paradigm has been challenged by the identification of "minimalist" histones in archaea and more recently by the discovery of genes that encode fused remote homologs of the four eukaryotic histones in Marseilleviridae, a subfamily of giant viruses that infect amoebae. We demonstrate that viral doublet histones are essential for viral infectivity, localize to cytoplasmic viral factories after virus infection, and ultimately are found in the mature virions. Cryogenic electron microscopy (cryo-EM) structures of viral nucleosome-like particles show strong similarities to eukaryotic nucleosomes despite the limited sequence identify. The unique connectors that link the histone chains contribute to the observed instability of viral nucleosomes, and some histone tails assume structural roles. Our results further expand the range of "organisms" that require nucleosomes and suggest a specialized function of histones in the biology of these unusual viruses.

A cyclic peptide inhibitor of the SARS-CoV-2 main protease.

This paper presents the design and study of a first-in-class cyclic peptide inhibitor against the SARS-CoV-2 main protease (Mpro). The cyclic peptide inhibitor is designed to mimic the conformation of a substrate at a C-terminal autolytic cleavage site of Mpro. The cyclic peptide contains a [4-(2-aminoethyl)phenyl]-acetic acid (AEPA) linker that is designed to enforce a conformation that mimics a peptide substrate of Mpro. In vitro evaluation of the cyclic peptide inhibitor reveals that the inhibitor exhibits modest activity against Mpro and does not appear to be cleaved by the enzyme. Conformational searching predicts that the cyclic peptide inhibitor is fairly rigid, adopting a favorable conformation for binding to the active site of Mpro. Computational docking to the SARS-CoV-2 Mpro suggests that the cyclic peptide inhibitor can bind the active site of Mpro in the predicted manner. Molecular dynamics simulations provide further insights into how the cyclic peptide inhibitor may bind the active site of Mpro. Although the activity of the cyclic peptide inhibitor is modest, its design and study lays the groundwork for the development of additional cyclic peptide inhibitors against Mpro with improved activities.

Structure-based drug design of an inhibitor of the SARS-CoV-2 (COVID-19) main protease using free software: A tutorial for students and scientists.

This paper describes the structure-based design of a preliminary drug candidate against COVID-19 using free software and publicly available X-ray crystallographic structures. The goal of this tutorial is to disseminate skills in structure-based drug design and to allow others to unleash their own creativity to design new drugs to fight the current pandemic. The tutorial begins with the X-ray crystallographic structure of the main protease (Mpro) of the SARS coronavirus (SARS-CoV) bound to a peptide substrate and then uses the UCSF Chimera software to modify the substrate to create a cyclic peptide inhibitor within the Mpro active site. Finally, the tutorial uses the molecular docking software AutoDock Vina to show the interaction of the cyclic peptide inhibitor with both SARS-CoV Mpro and the highly homologous SARS-CoV-2 Mpro. The supporting information provides an illustrated step-by-step protocol, as well as a video showing the inhibitor design process, to help readers design their own drug candidates for COVID-19 and the coronaviruses that will cause future pandemics. An accompanying preprint in bioRxiv [https://doi.org/10.1101/2020.08.03.234872] describes the synthesis of the cyclic peptide and the experimental validation as an inhibitor of SARS-CoV-2 Mpro.

Structure-Based Drug Design of an Inhibitor of the SARS-CoV-2 (COVID-19) Main Protease Using Free Software: A Tutorial for Students and Scientists.

This paper describes the structure-based design of a preliminary drug candidate against COVID-19 using free software and publicly available X-ray crystallographic structures. The goal of this tutorial is to disseminate skills in structure-based drug design and to allow others to unleash their own creativity to design new drugs to fight the current pandemic. The tutorial begins with the X-ray crystallographic structure of the main protease (Mpro) of the SARS coronavirus (SARS-CoV) bound to a peptide substrate and then uses the UCSF Chimera software to modify the substrate to create a cyclic peptide inhibitor within the Mpro active site. Finally, the tutorial uses the molecular docking software AutoDock Vina to show the interaction of the cyclic peptide inhibitor with both SARS-CoV Mpro and the highly homologous SARS-CoV-2 Mpro. The supporting information (supplementary material) provides an illustrated step-by-step guide for the inhibitor design, to help readers design their own drug candidates for COVID-19 and the coronaviruses that will cause future pandemics. An accompanying preprint in bioRxiv [https://doi.org/10.1101/2020.08.03.234872] describes the synthesis of the cyclic peptide and the experimental validation as an inhibitor of SARS-CoV-2 Mpro.

Structure-Based Design of a Cyclic Peptide Inhibitor of the SARS-CoV-2 Main Protease

This paper presents the design and study of a first-in-class cyclic peptide inhibitor against the SARS-CoV-2 main protease (Mpro). The cyclic peptide inhibitor is designed to mimic the conformation of a substrate at a C-terminal autolytic cleavage site of Mpro. Synthesis and evaluation of a first-generation cyclic peptide inhibitor reveals that the inhibitor is active against Mpro in vitro and is non-toxic toward human cells in culture. The initial hit described in this manuscript, UCI-1, lays the groundwork for the development of additional cyclic peptide inhibitors against Mpro with improved activities.

IL-13 Predicts the Need for Mechanical Ventilation in COVID-19 Patients

Immune dysregulation is characteristic of the more severe stages of SARS-CoV-2 infection. Understanding the mechanisms by which the immune system contributes to COVID-19 severity may open new avenues to treatment. Here we report that elevated interleukin-13 (IL-13) was associated with the need for mechanical ventilation in two independent patient cohorts. In addition, patients who acquired COVID-19 while prescribed Dupilumab had less severe disease. In SARS-CoV-2 infected mice, IL-13 neutralization reduced death and disease severity without affecting viral load, demonstrating an immunopathogenic role for this cytokine. Following anti-IL-13 treatment in infected mice, in the lung, hyaluronan synthase 1 (Has1) was the most downregulated gene and hyaluronan accumulation was decreased. Blockade of the hyaluronan receptor, CD44, reduced mortality in infected mice, supporting the importance of hyaluronan as a pathogenic mediator, and indicating a new role for IL-13 in lung disease. Understanding the role of IL-13 and hyaluronan has important implications for therapy of COVID-19 and potentially other pulmonary diseases. SummaryL-13 levels are elevated in patients with severe COVID-19. In a mouse model of disease, IL-13 neutralization results in reduced disease and lung hyaluronan deposition. Similarly, blockade of hyaluronans receptor, CD44, reduces disease, highlighting a novel mechanism for IL-13-mediated pathology.

A novel interprofessional approach to end-of-life care education: A pilot study.

Navigating the biomedical, emotional, and logistical complexity of end-of-life (EOL) care requires seamless interprofessional teamwork. Unfortunately, EOL care, interprofessional collaboration, and the role of support services such as hospice are not adequately emphasized in nursing and medical curricula. This article describes a student-run program, entitled the "HeArt of Medicine", which was designed to foster a reflective and collaborative approach to EOL care. The program consists of three workshops with a novel blend of art, science, and practical information, highlighting the need for interprofessional teamwork. Participants were surveyed before and after the workshops on their attitudes toward EOL care. Composite participant scores after workshops demonstrated increased comfort with and knowledge of EOL care topics (p = 0.001). The results show that this program has had a positive impact on participants' knowledge, comfort, and collaboration in EOL settings.