A selective sweep in the Spike gene has driven SARS-CoV-2 human adaptation.

The coronavirus disease 2019 (COVID-19) pandemic underscores the need to better understand animal-to-human transmission of coronaviruses and adaptive evolution within new hosts. We scanned more than 182,000 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes for selective sweep signatures and found a distinct footprint of positive selection located around a non-synonymous change (A1114G; T372A) within the spike protein receptor-binding domain (RBD), predicted to remove glycosylation and increase binding to human ACE2 (hACE2), the cellular receptor. This change is present in all human SARS-CoV-2 sequences but not in closely related viruses from bats and pangolins. As predicted, T372A RBD bound hACE2 with higher affinity in experimental binding assays. We engineered the reversion mutant (A372T) and found that A372 (wild-type [WT]-SARS-CoV-2) enhanced replication in human lung cells relative to its putative ancestral variant (T372), an effect that was 20 times greater than the well-known D614G mutation. Our findings suggest that this mutation likely contributed to SARS-CoV-2 emergence from animal reservoirs or enabled sustained human-to-human transmission.

The E2 glycoprotein holds key residues for Mayaro virus adaptation to the urban Aedes aegypti mosquito.

Adaptation to mosquito vectors suited for transmission in urban settings is a major driver in the emergence of arboviruses. To better anticipate future emergence events, it is crucial to assess their potential to adapt to new vector hosts. In this work, we used two different experimental evolution approaches to study the adaptation process of an emerging alphavirus, Mayaro virus (MAYV), to Ae. aegypti, an urban mosquito vector of many other arboviruses. We identified E2-T179N as a key mutation increasing MAYV replication in insect cells and enhancing transmission after escaping the midgut of live Ae. aegypti. In contrast, this mutation decreased viral replication and binding in human fibroblasts, a primary cellular target of MAYV in humans. We also showed that MAYV E2-T179N generates reduced viremia and displays less severe tissue pathology in vivo in a mouse model. We found evidence in mouse fibroblasts that MAYV E2-T179N is less dependent on the Mxra8 receptor for replication than WT MAYV. Similarly, exogenous expression of human apolipoprotein receptor 2 and Mxra8 enhanced WT MAYV replication compared to MAYV E2-T179N. When this mutation was introduced in the closely related chikungunya virus, which has caused major outbreaks globally in the past two decades, we observed increased replication in both human and insect cells, suggesting E2 position 179 is an important determinant of alphavirus host-adaptation, although in a virus-specific manner. Collectively, these results indicate that adaptation at the T179 residue in MAYV E2 may result in increased vector competence-but coming at the cost of optimal replication in humans-and may represent a first step towards a future emergence event.

Identification of the functional PD-L1 interface region responsible for PD-1 binding and initiation of PD-1 signaling.

The PD-1/PD-L1 checkpoint pathway is important for regulating immune responses and can be targeted by immunomodulatory drugs to treat a variety of immune disorders. However, the precise protein-protein interactions required for the initiation of PD-1/PD-L1 signaling are currently unknown. Previously, we designed a series of first-generation PD-1 targeting peptides based on the native interface region of programmed death ligand 1 (PD-L1) that effectively reduced PD-1/PD-L1 binding. In this work, we further characterized the previously identified lead peptide, MN1.1, to identify key PD-1 binding residues and design an optimized peptide, MN1.4. We show MN1.4 is significantly more stable than MN1.1 in serum and retains the ability to block PD-1/PD-L1 complex formation. We further characterized the immunomodulatory effects of MN1.4 treatment by measuring markers of T cell activation in a co-culture model with ovarian cancer cells and peripheral blood mononuclear cells. We found MN1.4 treatment reduced cytokine secretion and suppressed T cell responses in a similar manner as recombinant PD-L1. Therefore, the PD-L1 interface region used to design MN1.4 appeared sufficient to initiate PD-1 signaling and likely represents the minimum necessary region of PD-L1 required for PD-1 recognition. We propose a peptide agonist for PD-1, such as MN1.4, could have several applications for treating autoimmune disorders caused by PD-1 deficiencies such as type 1 diabetes, inflammatory arthritis, or autoimmune side effects arising from monoclonal antibody-based cancer immunotherapies.

The structural analysis of the periplasmic domain of Sinorhizobium meliloti chemoreceptor McpZ reveals a novel fold and suggests a complex mechanism of transmembrane signaling.

Chemotaxis is a fundamental process whereby bacteria seek out nutrient sources and avoid harmful chemicals. For the symbiotic soil bacterium Sinorhizobium meliloti, the chemotaxis system also plays an essential role in the interaction with its legume host. The chemotactic signaling cascade is initiated through interactions of an attractant or repellent compound with chemoreceptors or methyl-accepting chemotaxis proteins (MCPs). S. meliloti possesses eight chemoreceptors to mediate chemotaxis. Six of these receptors are transmembrane proteins with periplasmic ligand-binding domains (LBDs). The specific functions of McpW and McpZ are still unknown. Here, we report the crystal structure of the periplasmic domain of McpZ (McpZPD) at 2.7 Å resolution. McpZPD assumes a novel fold consisting of three concatenated four-helix bundle modules. Through phylogenetic analyses, we discovered that this helical tri-modular domain fold arose within the Rhizobiaceae family and is still evolving rapidly. The structure, offering a rare view of a ligand-free dimeric MCP-LBD, reveals a novel dimerization interface. Molecular dynamics calculations suggest ligand binding will induce conformational changes that result in large horizontal helix movements within the membrane-proximal domains of the McpZPD dimer that are accompanied by a 5 Å vertical shift of the terminal helix toward the inner cell membrane. These results suggest a mechanism of transmembrane signaling for this family of MCPs that entails both piston-type and scissoring movements. The predicted movements terminate in a conformation that closely mirrors those observed in related ligand-bound MCP-LBDs.

Simulations of cross-amyloid aggregation of amyloid-ß and islet amyloid polypeptide fragments.

Amyloid-ß (Aß) and islet amyloid polypeptide (IAPP) are small peptides, classified as amyloids, that have the potential to self-assemble and form cytotoxic species, such as small soluble oligomers and large insoluble fibrils. The formation of Aß aggregates facilitates the progression of Alzheimer's disease (AD), while IAPP aggregates induce pancreatic ß-cell apoptosis, leading to exacerbation of type 2 diabetes (T2D). Cross-amyloid interactions between Aß and IAPP have been described both in vivo and in vitro, implying the role of Aß or IAPP as modulators of cytotoxic self-aggregation of each species, and suggesting that Aß-IAPP interactions are a potential molecular link between AD and T2D. Using molecular dynamics (MD) simulations, "hotspot" regions of the two peptides were studied to understand the formation of hexamers in a heterogeneous and homogeneous peptide-containing environment. Systems of only Aß(16-22) peptides formed antiparallel, ß-barrel-like structures, while systems of only IAPP(20-29) peptides formed stacked, parallel ß-sheets and had relatively unstable aggregation structures after 2 µs of simulation time. Systems containing both Aß and IAPP (1:1 ratio) hexamers showed antiparallel, ß-barrel-like structures, with an interdigitated arrangement of Aß(16-22) and IAPP(20-29). These ß-barrel structures have features of cytotoxic amyloid species identified in previous literature. Ultimately, this work seeks to provide atomistic insight into both the mechanism behind cross-amyloid interactions and structural morphologies of these toxic amyloid species.

Biophysical insights into OR2T7: Investigation of a potential prognostic marker for glioblastoma.

Glioblastoma multiforme (GBM) is the most aggressive and prevalent form of brain cancer, with an expected survival of 12-15 months following diagnosis. GBM affects the glial cells of the central nervous system, which impairs regular brain function including memory, hearing, and vision. GBM has virtually no long-term survival even with treatment, requiring novel strategies to understand disease progression. Here, we identified a somatic mutation in OR2T7, a G-protein-coupled receptor (GPCR), that correlates with reduced progression-free survival for glioblastoma (log rank p-value = 0.05), suggesting a possible role in tumor progression. The mutation, D125V, occurred in 10% of 396 glioblastoma samples in The Cancer Genome Atlas, but not in any of the 2504 DNA sequences in the 1000 Genomes Project, suggesting that the mutation may have a deleterious functional effect. In addition, transcriptome analysis showed that the p38α mitogen-activated protein kinase (MAPK), c-Fos, c-Jun, and JunB proto-oncogenes, and putative tumor suppressors RhoB and caspase-14 were underexpressed in glioblastoma samples with the D125V mutation (false discovery rate < 0.05). Molecular modeling and molecular dynamics simulations have provided preliminary structural insight and indicate a dynamic helical movement network that is influenced by the membrane-embedded, cytofacial-facing residue 125, demonstrating a possible obstruction of G-protein binding on the cytofacial exposed region. We show that the mutation impacts the "open" GPCR conformation, potentially affecting Gα-subunit binding and associated downstream activity. Overall, our findings suggest that the Val125 mutation in OR2T7 could affect glioblastoma progression by downregulating GPCR-p38 MAPK tumor-suppression pathways and impacting the biophysical characteristics of the structure that facilitates Gα-subunit binding. This study provides the theoretical basis for further experimental investigation required to confirm that the D125V mutation in OR2T7 is not a passenger mutation. With validation, the aforementioned mutation could represent an important prognostic marker and a potential therapeutic target for glioblastoma.

NMR Model of the Entire Membrane-Interacting Region of the HIV-1 Fusion Protein and Its Perturbation of Membrane Morphology.

HIV-1 envelope glycoprotein (Env) is a transmembrane protein that mediates membrane fusion and viral entry. The membrane-interacting regions of the Env, including the membrane-proximal external region (MPER), the transmembrane domain (TMD), and the cytoplasmic tail (CT), not only are essential for fusion and Env incorporation but also can strongly influence the antigenicity of the Env. Previous studies have incrementally revealed the structures of the MPER, the TMD, and the KS-LLP2 regions of the CT. Here, we determined the NMR structure of the full-length CT using a protein fragment comprising the TMD and the CT in bicelles that mimic a lipid bilayer, and by integrating the new NMR data and those acquired previously on other gp41 fragments, we derived a model of the entire membrane-interacting region of the Env. The structure shows that the CT forms a large trimeric baseplate around the TMD trimer, and by residing in the headgroup region of the lipid bilayer, the baseplate causes severe exclusion of lipid in the cytoleaflet of the bilayer. All-atom molecular dynamics simulations showed that the overall structure of the MPER-TMD-CT can be stable in a viral membrane and that a concerted movement of the KS-LLP2 region compensates for the lipid exclusion in order to maintain both structure and membrane integrity. Our structural and simulation results provide a framework for future research to manipulate the membrane structure to modulate the antigenicity of the Env for vaccine development and for mutagenesis studies for investigating membrane fusion and Env interaction with the matrix proteins.

Lipophilic tail modifications of 2-(hydroxymethyl)pyrrolidine scaffold reveal dual sphingosine kinase 1 and 2 inhibitors.

The sphingosine 1-phosphate (S1P) signaling pathway is an attractive target for pharmacological manipulation due to its involvement in cancer progression and immune cell chemotaxis. The synthesis of S1P is catalyzed by the action of sphingosine kinase 1 or 2 (SphK1 or SphK2) on sphingosine and ATP. While potent and selective inhibitors of SphK1 or SphK2 have been reported, development of potent dual SphK1/SphK2 inhibitors are still needed. Towards this end, we report the structure-activity relationship profiling of 2-(hydroxymethyl)pyrrolidine-based inhibitors with 22d being the most potent dual SphK1/SphK2 inhibitor (SphK1 Ki = 0.679 µM, SphK2 Ki = 0.951 µM) reported in this series. 22d inhibited the growth of engineered Saccharomyces cerevisiae and decreased S1P levels in histiocytic lymphoma myeloid cell line (U937 cells), demonstrating inhibition of SphK1 and 2 in vitro. Molecular modeling studies of 22d docked inside the Sph binding pocket of both SphK1 and SphK2 indicate essential hydrogen bond between the 2-(hydroxymethyl)pyrrolidine head to interact with aspartic acid and serine residues near the ATP binding pocket, which provide the basis for dual inhibition. In addition, the dodecyl tail adopts a "J-shape" conformation found in crystal structure of sphingosine bound to SphK1. Collectively, these studies provide insight into the intermolecular interactions in the SphK1 and 2 active sites to achieve maximal dual inhibitory activity.

In Silico Characterization of Structural Distinctions between Isoforms of Human and Mouse Sphingosine Kinases for Accelerating Drug Discovery.

Alterations in cellular signaling pathways are associated with multiple disease states including cancers and fibrosis. Current research efforts to attenuate cancers, specifically lymphatic cancer, focus on inhibition of two sphingosine kinase isoforms, sphingosine kinase 1 (SphK1) and sphingosine kinase 2 (SphK2). Determining differences in structural and physicochemical binding site properties of SphKs is attractive to refine inhibitor potency and isoform selectivity. This study utilizes a predictive in silico approach to determine key differences in binding sites in SphK isoforms in human and mouse species. Homology modeling, molecular docking of inhibitors, analysis of binding pocket residue positions, development of pharmacophore models, and analysis of binding cavity volume were performed to determine isoform- and species-selective characteristics of the binding site and generate a system to rank potential inhibitors. Interestingly, docking studies showed compounds bound to mouse SphK1 in a manner more similar to human SphK2 than to human SphK1, indicating that SphKs in mice have structural properties distinct from humans that confounds prediction of ligand selectivity in mice. Our studies aid in the development and production of new compound classes by highlighting structural distinctions and identifying the role of key residues that cause observable, functional differences in isoforms and between orthologues.

Structure of the sensory domain of McpX from Sinorhizobium meliloti, the first known bacterial chemotactic sensor for quaternary ammonium compounds.

The α-proteobacterium Sinorhizobium meliloti can live freely in the soil or engage in a symbiosis with its legume host. S. meliloti facilitates nitrogen fixation in root nodules, thus providing pivotal, utilizable nitrogen to the host. The organism has eight chemoreceptors, namely McpT to McpZ and IcpA that facilitate chemotaxis. McpX is the first known bacterial sensor of quaternary ammonium compounds (QACs) such as choline and betaines. Because QACs are exuded at chemotaxis-relevant concentrations by germinating alfalfa seeds, McpX has been proposed to contribute to host-specific chemotaxis. We have determined the crystal structure of the McpX periplasmic region (McpXPR) in complex with the proline betaine at 2.7 Å resolution. In the crystal, the protein forms a symmetric dimer with one proline betaine molecule bound to each monomer of McpXPR within membrane-distal CACHE module. The ligand is bound through cation-πinteractions with four aromatic amino acid residues. Mutational analysis in conjunction with binding studies revealed that a conserved aspartate residue is pivotal for ligand binding. We discovered that, in a striking example of convergent evolution, the ligand-binding site of McpXPR resembles that of a group of structurally unrelated betaine-binding proteins including ProX and OpuAC. Through this comparison and docking studies, we rationalized the specificity of McpXPR for this specific group of ligands. Collectively, our structural, biochemical, and molecular docking data have revealed the molecular determinants in McpX that are crucial for its rare ligand specificity for QACs.

HIV-1 Env gp41 Transmembrane Domain Dynamics Are Modulated by Lipid, Water, and Ion Interactions.

The gp41 transmembrane domain (TMD) of the envelope glycoprotein of the human immunodeficiency virus modulates the conformation of the viral envelope spike, the only druggable target on the surface of the virion. Targeting the envelope glycoprotein with small-molecule and antibody therapies requires an understanding of gp41 TMD dynamics, which is often challenging given the difficulties in describing native membrane properties. Here, atomistic molecular dynamics simulations of a trimeric, prefusion gp41 TMD in a model, asymmetric viral membrane that mimics the native viral envelope were performed. Water and chloride ions were observed to permeate the membrane and interact with the highly conserved arginine bundle, (R696)3, at the center of the membrane and influenced TMD stability by creating a network of hydrogen bonds and electrostatic interactions. We propose that this (R696)3 - water - anion network plays an important role in viral fusion with the host cell by modulating protein conformational changes within the membrane. Additionally, R683 and R707 at the exofacial and cytofacial membrane-water interfaces, respectively, are anchored in the lipid headgroup region and serve as a junction point for stabilization of the termini. The membrane thins as a result of the tilting of the gp41 trimer with nearby lipids increasing in volume, leading to an entropic driving force for TMD conformational change. These results provide additional detail and perspective on the influence of certain lipid types on TMD dynamics and a rationale for targeting key residues of the TMD for therapeutic design. These insights into the molecular details of TMD membrane anchoring will build toward a greater understanding of the dynamics that lead to viral fusion with the host cell.

Influence of sequence and lipid type on membrane perturbation by human and rat amyloid ß-peptide (1-42).

The hallmark characteristics of plaque formation and neuronal cell death in Alzheimer's disease (AD) are caused principally by the amyloid ß-peptide (Aß). Aß sequence and lipid composition are essential variables to consider when elucidating the impact of biological membranes on Aß structure and the effect of Aß on membrane integrity. Atomistic molecular dynamics simulations testing two Aß sequences, human and rat Aß (HAß and RAß, respectively), and five lipid types were performed to assess the effect of these variables on membrane perturbation and potential link to AD phenotype differences based on differences in sequence. All metrics agree insomuch that monomeric HAß and RAß contribute to membrane perturbation by causing a more rigid, gel-like lipid phase. Differences between HAß and RAß binding on degree of membrane perturbation were based on lipid headgroup properties. Cholesterol was found to moderate the amount of perturbation caused by HAß and RAß in a model raft membrane. The difference in position of an arginine residue between HAß and RAß influenced peptide-membrane interactions and was determined to be the mediating factor in observed differences in lipid affinity and degree of membrane disruption. Overall, this work increases our understanding of the influence of sequence and lipid type on Aß-membrane interactions and their relationship to AD.

Molecular Dynamics Simulations of Amyloid ß-Peptide (1-42): Tetramer Formation and Membrane Interactions.

The aggregation cascade and peptide-membrane interactions of the amyloid ß-peptide (Aß) have been implicated as toxic events in the development and progression of Alzheimer's disease. Aß42 forms oligomers and ultimately plaques, and it has been hypothesized that these oligomeric species are the main toxic species contributing to neuronal cell death. To better understand oligomerization events and subsequent oligomer-membrane interactions of Aß42, we performed atomistic molecular-dynamics (MD) simulations to characterize both interpeptide interactions and perturbation of model membranes by the peptides. MD simulations were utilized to first show the formation of a tetramer unit by four separate Aß42 peptides. Aß42 tetramers adopted an oblate ellipsoid shape and showed a significant increase in ß-strand formation in the final tetramer unit relative to the monomers, indicative of on-pathway events for fibril formation. The Aß42 tetramer unit that formed in the initial simulations was used in subsequent MD simulations in the presence of a pure POPC or cholesterol-rich raft model membrane. Tetramer-membrane simulations resulted in elongation of the tetramer in the presence of both model membranes, with tetramer-raft interactions giving rise to the rearrangement of key hydrophobic regions in the tetramer and the formation of a more rod-like structure indicative of a fibril-seeding aggregate. Membrane perturbation by the tetramer was manifested in the form of more ordered, rigid membranes, with the pure POPC being affected to a greater extent than the raft membrane. These results provide critical atomistic insight into the aggregation pathway of Aß42 and a putative toxic mechanism in the pathogenesis of Alzheimer's disease.

Purine salvage in Methanocaldococcus jannaschii: Elucidating the role of a conserved cysteine in adenine deaminase.

Adenine deaminases (Ade) and hypoxanthine/guanine phosphoribosyltransferases (Hpt) are widely distributed enzymes involved in purine salvage. Characterization of the previously uncharacterized Ade (MJ1459 gene product) and Hpt (MJ1655 gene product) are discussed here and provide insight into purine salvage in Methanocaldococcus jannaschii. Ade was demonstrated to use either Fe(II) and/or Mn(II) as the catalytic metal. Hpt demonstrated no detectable activity with adenine, but was equally specific for hypoxanthine and guanine with a kcat /KM of 3.2 × 10(7) and 3.0 × 10(7) s(- 1) M(- 1) , respectively. These results demonstrate that hypoxanthine and IMP are the central metabolites in purine salvage in M. jannaschii for AMP and GMP production. A conserved cysteine (C127, M. jannaschii numbering) was examined due to its high conservation in bacterial and archaeal homologues. To assess the role of this highly conserved cysteine in M. jannaschii Ade, site-directed mutagenesis was performed. It was determined that mutation to serine (C127S) completely abolished Ade activity and mutation to alanine (C127A) exhibited 10-fold decrease in kcat over the wild type Ade. To further investigate the role of C127, detailed molecular docking and dynamics studies were performed and revealed adenine was unable to properly orient in the active site in the C127A and C127S Ade model structures due to distinct differences in active site conformation and rotation of D261. Together this work illuminates purine salvage in M. jannaschii and the critical role of a cysteine residue in maintaining active site conformation of Ade. Proteins 2016; 84:828-840. © 2016 Wiley Periodicals, Inc.

Simulations of monomeric amyloid ß-peptide (1-40) with varying solution conditions and oxidation state of Met35: implications for aggregation.

The amyloid ß-peptide (Aß) is a 40-42 residue peptide that is the principal toxic species in Alzheimer's disease (AD). The oxidation of methionine-35 (Met35) to the sulfoxide form (Met35(ox)) has been identified as potential modulator of Aß aggregation. The role Met35(ox) plays in Aß neurotoxicity differs among experimental studies, which may be due to inconsistent solution conditions (pH, buffer, temperature). We applied atomistic molecular dynamics (MD) simulations as a means to probe the dynamics of the monomeric 40-residue alloform of Aß (Aß40) containing Met35 or Met35(ox) in an effort to resolve the conflicting experimental results. We found that Met35 oxidation decreases the ß-strand content of the C-terminal hydrophobic region (residues 29-40), with a specific effect on the secondary structure of residues 33-35, thus potentially impeding aggregation. Further, there is an important interplay between oxidation state and solution conditions, with pH and salt concentration augmenting the effects of oxidation. The results presented here serve to rationalize the conflicting results seen in experimental studies and provide a fundamental biophysical characterization of monomeric Aß40 dynamics in both reduced and oxidized forms, providing insight into the biochemical mechanism of Aß40 and oxidative stress related to AD.

Pain quality of life as measured by utilities.

OBJECTIVE: Utilities are values of health-related quality of life (HRQoL) based on patient preference for a health status. The purpose of this study was to compare indirect measures to a directly elicited utility. DESIGN: Cross-sectional study. SETTING AND PATIENTS: Emory Spine Center and the Emory Center for Chronic Pain at Crawford Long Hospital. Patients at least 18 years of age with chronic pain, defined as pain that persists beyond the normal time of healing, usually beyond 6 months. MEASURES: Chronic pain subjects completed a paper-based, self-administered time trade-off (TTO) survey, EQ-5D survey, and a face-to-face (FTF) TTO interview. Current pain severity was graded using the Numeric Rating Scale-11, subsequently stratified into no (0), mild (1-3), moderate (4-6), and severe (7-10) pain. RESULTS: Paired t test comparing FTF TTO and proxy utility measures stratified by severity revealed FTF TTO utility values significantly higher than EQ-5D utility values for all pain severities (overall mean difference 0.18, standard deviation [SD] 0.30, P < 0.001; Pearson's correlation 0.34, P < 0.0001); FTF TTO utility values were lower than paper TTO utility values, reaching statistical significance for mild and moderate pain (overall mean difference 0.09, SD 0.29, P = 0.0006; Pearson's correlation 0.38, P < 0.0001). CONCLUSIONS: This study demonstrates that the EQ-5D overestimates, whereas the paper version of TTO underestimates, the impact of pain on HRQoL compared with the directly elicited FTF TTO utility. Our findings provide preliminary evidence that utilities vary by method, and directly elicited utility values differ from indirectly elicited measures.

Forgotten Natural Products: Semisynthetic Development of Blasticidin S As an Antibiotic Lead.

Forgotten natural products offer value as antimicrobial scaffolds, providing diverse mechanisms of action that complement existing antibiotic classes. This study focuses on the derivatization of the cytotoxin blasticidin S, seeking to leverage its unique ribosome inhibition mechanism. Despite its complex zwitterionic properties, a selective protection and amidation strategy enabled the creation of a library of blasticidin S derivatives including the natural product P10. The amides exhibited significantly increased activity against Gram-positive bacteria and enhanced specificity for pathogenic bacteria over human cells. Molecular docking and computational property analysis suggested variable binding poses and indicated a potential correlation between cLogP values and activity. This work demonstrates how densely functionalized forgotten antimicrobials can be straightforwardly modified, enabling the further development of blasticidin S derivatives as lead compounds for a novel class of antibiotics.

Discovery of Potent, Orally Bioavailable Sphingosine-1-Phosphate Transporter (Spns2) Inhibitors.

Targeting the S1P pathway has resulted in the development of S1P1 receptor modulators for the treatment of multiple sclerosis and ulcerative colitis. We hypothesize that targeting an upstream node of the S1P pathway may provide an improved adverse event profile. In this report, we performed a structure-activity relationship study focusing on the benzoxazole scaffold in SLB1122168, which lead to the discovery of 11i (SLF80821178) as a potent inhibitor of S1P release from HeLa cells (IC50: 51 ± 3 nM). Administration of SLF80821178 to mice induced ∼50% reduction in circulating lymphocyte counts, recapitulating the lymphopenia characteristic of Spns2 null animals. Molecular modeling studies suggest that SLF80821178 binds Spns2 in its occluded inward-facing state and forms hydrogen bonds with Asn112 and Ser211 and π stacking with Phe234. Taken together, SLF80821178 can serve as a scaffold for future inhibitor development and represents a chemical tool to study the therapeutic implication of inhibiting Spns2.

Data Driven Computational Design and Experimental Validation of Drugs for Accelerated Mitigation of Pandemic-like Scenarios.

Emerging pathogens are a historic threat to public health and economic stability. Current trial-and-error approaches to identify new therapeutics are often ineffective due to their inefficient exploration of the enormous small molecule design space. Here, we present a data-driven computational framework composed of hybrid evolutionary algorithms for evolving functional groups on existing drugs to improve their binding affinity toward the main protease (Mpro) of SARS-CoV-2. We show that combinations of functional groups and sites are critical to design drugs with improved binding affinity, which can be easily achieved using our framework by exploring a fraction of the available search space. Atomistic simulations and experimental validation elucidate that enhanced and prolonged interactions between functionalized drugs and Mpro residues result in their improved therapeutic value over that of the parental compound. Overall, this novel framework is extremely flexible and has the potential to rapidly design inhibitors for any protein with available crystal structures.

An international consensus on effective, inclusive, and career-spanning short-format training in the life sciences and beyond.

Science, technology, engineering, mathematics, and medicine (STEMM) fields change rapidly and are increasingly interdisciplinary. Commonly, STEMM practitioners use short-format training (SFT) such as workshops and short courses for upskilling and reskilling, but unaddressed challenges limit SFT's effectiveness and inclusiveness. Education researchers, students in SFT courses, and organizations have called for research and strategies that can strengthen SFT in terms of effectiveness, inclusiveness, and accessibility across multiple dimensions. This paper describes the project that resulted in a consensus set of 14 actionable recommendations to systematically strengthen SFT. A diverse international group of 30 experts in education, accessibility, and life sciences came together from 10 countries to develop recommendations that can help strengthen SFT globally. Participants, including representation from some of the largest life science training programs globally, assembled findings in the educational sciences and encompassed the experiences of several of the largest life science SFT programs. The 14 recommendations were derived through a Delphi method, where consensus was achieved in real time as the group completed a series of meetings and tasks designed to elicit specific recommendations. Recommendations cover the breadth of SFT contexts and stakeholder groups and include actions for instructors (e.g., make equity and inclusion an ethical obligation), programs (e.g., centralize infrastructure for assessment and evaluation), as well as organizations and funders (e.g., professionalize training SFT instructors; deploy SFT to counter inequity). Recommendations are aligned with a purpose-built framework-"The Bicycle Principles"-that prioritizes evidenced-based teaching, inclusiveness, and equity, as well as the ability to scale, share, and sustain SFT. We also describe how the Bicycle Principles and recommendations are consistent with educational change theories and can overcome systemic barriers to delivering consistently effective, inclusive, and career-spanning SFT.