Developing therapeutics against SARS-CoV-2 could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the Spike (S) protein, but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from ten convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. An mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2, but does not bind the RBD. We defined the epitope of 4A8 as the N terminal domain (NTD) of the S protein by determining its cryo-EM structure in complex with the S protein to an overall resolution of 3.1 Angstrom and local resolution of 3.3 Angstrom for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.

The biogenesis of exosomes, small secreted vesicles involved in signalling processes, remains incompletely understood. Here, we report evidence that the syndecan heparan sulphate proteoglycans and their cytoplasmic adaptor syntenin control the formation of exosomes. Syntenin interacts directly with ALIX through LYPX(n)L motifs, similarly to retroviral proteins, and supports the intraluminal budding of endosomal membranes. Syntenin exosomes depend on the availability of heparan sulphate, syndecans, ALIX and ESCRTs, and impact on the trafficking and confinement of FGF signals. This study identifies a key role for syndecan-syntenin-ALIX in membrane transport and signalling processes.

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Background This is the first randomised controlled trial for assessment of the immunogenicity and safety of a candidate non-replicating adenovirus type-5 (Ad5)-vectored COVID-19 vaccine, aiming to determine an appropriate dose of the candidate vaccine for an efficacy study. Methods This randomised, double-blind, placebo-controlled, phase 2 trial of the Ad5-vectored COVID-19 vaccine was done in a single centre in Wuhan, China. Healthy adults aged 18 years or older, who were HIV-negative and previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-free, were eligible to participate and were randomly assigned to receive the vaccine at a dose of 1 × 10 11 viral particles per mL or 5 × 10 10 viral particles per mL, or placebo. Investigators allocated participants at a ratio of 2:1:1 to receive a single injection intramuscularly in the arm. The randomisation list (block size 4) was generated by an independent statistician. Participants, investigators, and staff undertaking laboratory analyses were masked to group allocation. The primary endpoints for immunogenicity were the geometric mean titres (GMTs) of specific ELISA antibody responses to the receptor binding domain (RBD) and neutralising antibody responses at day 28. The primary endpoint for safety evaluation was the incidence of adverse reactions within 14 days. All recruited participants who received at least one dose were included in the primary and safety analyses. This study is registered with ClinicalTrials.gov , NCT04341389 . Findings 603 volunteers were recruited and screened for eligibility between April 11 and 16, 2020. 508 eligible participants (50% male; mean age 39·7 years, SD 12·5) consented to participate in the trial and were randomly assigned to receive the vaccine (1 × 10 11 viral particles n=253; 5 × 10 10 viral particles n=129) or placebo (n=126). In the 1 × 10 11 and 5 × 10 10 viral particles dose groups, the RBD-specific ELISA antibodies peaked at 656·5 (95% CI 575·2–749·2) and 571·0 (467·6–697·3), with seroconversion rates at 96% (95% CI 93–98) and 97% (92–99), respectively, at day 28. Both doses of the vaccine induced significant neutralising antibody responses to live SARS-CoV-2, with GMTs of 19·5 (95% CI 16·8–22·7) and 18·3 (14·4–23·3) in participants receiving 1 × 10 11 and 5 × 10 10 viral particles, respectively. Specific interferon γ enzyme-linked immunospot assay responses post vaccination were observed in 227 (90%, 95% CI 85–93) of 253 and 113 (88%, 81–92) of 129 participants in the 1 × 10 11 and 5 × 10 10 viral particles dose groups, respectively. Solicited adverse reactions were reported by 183 (72%) of 253 and 96 (7...

Although serum from patients with Parkinson's disease contains elevated levels of numerous pro-inflammatory cytokines including IL-6, TNF, IL-1β, and IFNγ, whether inflammation contributes to or is a consequence of neuronal loss remains unknown. Mutations in parkin, an E3 ubiquitin ligase, and PINK1, a ubiquitin kinase, cause early onset Parkinson's disease. Both PINK1 and parkin function within the same biochemical pathway and remove damaged mitochondria from cells in culture and in animal models via mitophagy, a selective form of autophagy. The in vivo role of mitophagy, however, is unclear, partly because mice that lack either PINK1 or parkin have no substantial Parkinson's-disease-relevant phenotypes. Mitochondrial stress can lead to the release of damage-associated molecular patterns (DAMPs) that can activate innate immunity, suggesting that mitophagy may mitigate inflammation. Here we report a strong inflammatory phenotype in both Prkn and Pink1 mice following exhaustive exercise and in Prkn;mutator mice, which accumulate mutations in mitochondrial DNA (mtDNA). Inflammation resulting from either exhaustive exercise or mtDNA mutation is completely rescued by concurrent loss of STING, a central regulator of the type I interferon response to cytosolic DNA. The loss of dopaminergic neurons from the substantia nigra pars compacta and the motor defect observed in aged Prkn;mutator mice are also rescued by loss of STING, suggesting that inflammation facilitates this phenotype. Humans with mono- and biallelic PRKN mutations also display elevated cytokines. These results support a role for PINK1- and parkin-mediated mitophagy in restraining innate immunity.

The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that uniquely functions as an ion channel. Here, we present a 3.9 Å structure of dephosphorylated human CFTR without nucleotides, determined by electron cryomicroscopy (cryo-EM). Close resemblance of this human CFTR structure to zebrafish CFTR under identical conditions reinforces its relevance for understanding CFTR function. The human CFTR structure reveals a previously unresolved helix belonging to the R domain docked inside the intracellular vestibule, precluding channel opening. By analyzing the sigmoid time course of CFTR current activation, we propose that PKA phosphorylation of the R domain is enabled by its infrequent spontaneous disengagement, which also explains residual ATPase and gating activity of dephosphorylated CFTR. From comparison with MRP1, a feature distinguishing CFTR from all other ABC transporters is the helix-loop transition in transmembrane helix 8, which likely forms the structural basis for CFTR's channel function.

Implicit methods for modeling protein electrostatics require dielectric properties of the system to be known, in particular, the value of the dielectric constant of protein. While numerous values of the internal protein dielectric constant were reported in the literature, still there is no consensus of what the optimal value is. Perhaps this is due to the fact that the protein dielectric constant is not a “constant” but is a complex function reflecting the properties of the protein’s structure and sequence. Here, we report an implementation of a Gaussian-based approach to deliver the dielectric constant distribution throughout the protein and surrounding water phase by utilizing the 3D structure of the corresponding macromolecule. In contrast to previous reports, we construct a smooth dielectric function throughout the space of the system to be modeled rather than just constructing a “Gaussian surface” or smoothing molecule–water boundary. Analysis on a large set of proteins shows that (a) the average dielectric constant inside the protein is relatively low, about 6–7, and reaches a value of about 20–30 at the protein’s surface, and (b) high average local dielectric constant values are associated with charged residues while low dielectric constant values are automatically assigned to the regions occupied by hydrophobic residues. In terms of energetics, a benchmarking test was carried out against the experimental pKa’s of 89 residues in staphylococcal nuclease (SNase) and showed that it results in a much better RMSD (= 1.77 pK) than the corresponding calculations done with a homogeneous high dielectric constant with an optimal value of 10 (RMSD = 2.43 pK).

BACKGROUND & AIMS The risk of pancreatic cancer is increased in patients with a strong family history of pancreatic cancer or a predisposing germline mutation. Screening can detect curable, non-invasive pancreatic neoplasms, but the optimal imaging approach is not known. We determined the baseline prevalence and characteristics of pancreatic abnormalities using 3 imaging tests to screen asymptomatic, high-risk individuals (HRI). METHODS We screened 225 asymptomatic adult HRI at 5 academic US medical centers once, using computed tomography (CT), magnetic resonance imaging (MRI), and endoscopic ultrasonography (EUS). We compared results in a blinded, independent fashion. RESULTS Ninety-two of 216 HRI (42%) were found to have at least 1 pancreatic mass (84 cystic, 3 solid) or a dilated pancreatic duct (n=5) by any of the imaging modalities. Fifty-one of the 84 HRI with a cyst (60.7%) had multiple lesions, typically small (mean 0.55 cm, range 2–39 mm), in multiple locations. The prevalence of pancreatic lesions increased with age; they were detected in 14% of subjects <50 years old, 34% of subjects 50–59 years old, and 53% of subjects 60–69 years old (P<.0001). CT, MRI, and EUS detected a pancreatic abnormality in 11%, 33.3%, and 42.6% of the HRI, respectively. Among these abnormalities, proven or suspected neoplasms were identified in 85 HRI (82 intraductal papillary mucinous neoplasms [IPMN] and 3 pancreatic endocrine tumors). Three of 5 HRI who underwent pancreatic resection had high-grade dysplasia in <3 cm IPMNs and in multiple intraepithelial neoplasias. CONCLUSIONS Screening of asymptomatic HRI frequently detects small pancreatic cysts, including curable, non-invasive high-grade neoplasms. EUS and MRI detect pancreatic lesions better than CT.