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A high-throughput screen of preclinical, investigational and FDA-approved drugs identifies compounds that possess antiviral and neuroprotective effects against Zika virus infection in human neural progenitor cells and astrocytes. In response to the current global health emergency posed by the Zika virus (ZIKV) outbreak and its link to microcephaly and other neurological conditions, we performed a drug repurposing screen of ∼6,000 compounds that included approved drugs, clinical trial drug candidates and pharmacologically active compounds; we identified compounds that either inhibit ZIKV infection or suppress infection-induced caspase-3 activity in different neural cells. A pan-caspase inhibitor, emricasan, inhibited ZIKV-induced increases in caspase-3 activity and protected human cortical neural progenitors in both monolayer and three-dimensional organoid cultures. Ten structurally unrelated inhibitors of cyclin-dependent kinases inhibited ZIKV replication. Niclosamide, a category B anthelmintic drug approved by the US Food and Drug Administration, also inhibited ZIKV replication. Finally, combination treatments using one compound from each category (neuroprotective and antiviral) further increased protection of human neural progenitors and astrocytes from ZIKV-induced cell death. Our results demonstrate the efficacy of this screening strategy and identify lead compounds for anti-ZIKV drug development.

Females influence offspring paternity through diverse pre- and post-copulatory mechanisms. Sperm discrimination—the differential physiological response to ejaculates based on male or sperm characteristics—can bias fertilization outcomes, but in vivo evidence of this process in large-bodied mammals is lacking. Here, in a study of nine females and four males, we tested whether two aspects of female physiology that affect sperm survival—vaginal immune response and pH—are modulated by male genetic makeup in a non-human primate, the olive baboon ( Papio anubis ). Our findings suggest post-copulatory differences in vaginal gene expression and pH, with the strongest immune responses and largest pH decreases, harmful to sperm, exhibited by females mating with genetically similar males. These findings are consistent with genetically-based post-copulatory mate discrimination, offering new insights into how interactions between male gametes and the female reproductive tract may shape conception probability in primates.

Chikungunya virus (CHIKV) is a mosquito-borne RNA virus that has emerged as one of the most important global arboviral threats in the last decade. Although the first CHIKV vaccine has recently been FDA approved for use in healthy adults at increased risk, to date, there are no available antiviral drugs for CHIKV infection. CHIKV nsP2 protease plays a crucial role in the processing of the viral polypeptide precursor to release enzymes required for viral replication, thus making it a promising drug target for antiviral discovery. Here, we established a high-throughput pipeline to identify small molecule inhibitors of nsP2 proteolytic activity. The pipeline is composed of a suite of 1,536-well in vitro assays to support quantitative high-throughput (qHTS) screening campaigns. Specifically, we developed a fluorescence resonance energy transfer (FRET)-based assay using a fluorogenic peptide substrate encompassing an endogenous cleavage site and purified recombinant protease domain (nsP2pro). Using this assay, we interrogated ~ 31,000 unique small molecules, including those in drug repurposing libraries as well as chemically diverse and medicinal chemistry-friendly compounds. Hits were selected for follow-up validation against full-length nsP2 and an additional peptide. FRET-based 1,536-well assays for Papain, hepatitis C virus NS3-4A, and human Furin proteases were implemented to characterize compound selectivity. Notably, we developed a high-throughput cell-based proteolytic assay using a split nanoluciferase reporter to identify cell-active hits. Novel compounds were found to be potential nsP2 inhibitors and molecular docking analyses were performed to explain the binding mode of selected hits. In vitro antiviral activity was evaluated for a subset of compounds using a high-throughput CHIKV infection assay. To our knowledge, the pipeline presented here is unprecedented for CHIKV antiviral discovery research.

Neutralizing antibodies targeting the SARS-CoV-2 spike protein have shown a great preventative/therapeutic potential. Here, we report a rapid and efficient strategy for the development and design of SARS-CoV-2 neutralizing humanized nanobody constructs with sub-nanomolar affinities and nanomolar potencies. CryoEM-based structural analysis of the nanobodies in complex with spike revealed two distinct binding modes. The most potent nanobody, RBD-1-2G(NCATS-BL8125), tolerates the N501Y RBD mutation and remains capable of neutralizing the B.1.1.7 (Alpha) variant. Molecular dynamics simulations provide a structural basis for understanding the neutralization process of nanobodies exclusively focused on the spike-ACE2 interface with and without the N501Y mutation on RBD. A primary human airway air-lung interface (ALI) ex vivo model showed that RBD-1-2G-Fc antibody treatment was effective at reducing viral burden following WA1 and B.1.1.7 SARS-CoV-2 infections. Therefore, this presented strategy will serve as a tool to mitigate the threat of emerging SARS-CoV-2 variants.

3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we describe a method for generating functional neural spheroids by cell-aggregation of differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modeling, drug testing, and formation of assembloids to model neurocircuitry. As a proof of concept, we generated spheroids incorporating neurons with Alzheimer’s disease-associated alleles, as well as opioid use disorder modeling spheroids induced by chronic treatment of a mu-opioid receptor agonist. We reversed baseline functional deficits in each pilot disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific neural spheroids as a robust functional assay platform for HTS studies. The authors describe a method for generating functional neural spheroids and assembloids for disease modeling and drug discovery by cell aggregation of differentiated human iPSC derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain.

There is a critical need for physiologically relevant, robust, and ready-to-use in vitro cellular assay platforms to rapidly model the infectivity of emerging viruses and develop new antiviral treatments. Here we describe the cellular complexity of human alveolar and tracheobronchial air liquid interface (ALI) tissue models during SARS-CoV-2 and influenza A virus (IAV) infections. Our results showed that both SARS-CoV-2 and IAV effectively infect these ALI tissues, with SARS-CoV-2 exhibiting a slower replication peaking at later time-points compared to IAV. We detected tissue-specific chemokine and cytokine storms in response to viral infection, including well-defined biomarkers in severe SARS-CoV-2 and IAV infections such as CXCL10, IL-6, and IL-10. Our single-cell RNA sequencing analysis showed similar findings to that found in vivo for SARS-CoV-2 infection, including dampened IFN response, increased chemokine induction, and inhibition of MHC Class I presentation not observed for IAV infected tissues. Finally, we demonstrate the pharmacological validity of these ALI tissue models as antiviral drug screening assay platforms, with the potential to be easily adapted to include other cell types and increase the throughput to test relevant pathogens. Human alveolar and tracheobronchial epithelial air liquid interface (ALI) tissues are used as models to examine cellular responses to SARS-CoV-2 and influenza A virus infections and as antiviral drug screening assay platforms.

Zika virus infection is associated with neurological disorders, yet few studies have directly examined its impact on the peripheral nervous system. Oh et al . show that Zika virus can infect peripheral neurons in the mouse in vivo , as well as human peripheral neurons in vitro , leading to increased cell death and transcriptional dysregulation. Zika virus (ZIKV) infection is associated with neurological disorders of both the CNS and peripheral nervous systems (PNS), yet few studies have directly examined PNS infection. Here we show that intraperitoneally or intraventricularly injected ZIKV in the mouse can infect and impact peripheral neurons in vivo . Moreover, ZIKV productively infects stem-cell-derived human neural crest cells and peripheral neurons in vitro , leading to increased cell death, transcriptional dysregulation and cell-type-specific molecular pathology.

Computational approaches for drug discovery, such as quantitative structure–activity relationship, rely on structural similarities of small molecules to infer biological activity but are often limited to identifying new drug candidates in the chemical spaces close to known ligands. Here we report a biological activity-based modeling (BABM) approach, in which compound activity profiles established across multiple assays are used as signatures to predict compound activity in other assays or against a new target. This approach was validated by identifying candidate antivirals for Zika and Ebola viruses based on high-throughput screening data. BABM models were then applied to predict 311 compounds with potential activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Of the predicted compounds, 32% had antiviral activity in a cell culture live virus assay, the most potent compounds showing a half-maximal inhibitory concentration in the nanomolar range. Most of the confirmed anti-SARS-CoV-2 compounds were found to be viral entry inhibitors and/or autophagy modulators. The confirmed compounds have the potential to be further developed into anti-SARS-CoV-2 therapies. Activity profiles generated from quantitative high-throughput screening improve drug candidate prediction.

The re-emergence of Zika virus (ZIKV) and Ebola virus (EBOV) poses serious and continued threats to the global public health. Effective therapeutics for these maladies is an unmet need. Here, we show that emetine, an anti-protozoal agent, potently inhibits ZIKV and EBOV infection with a low nanomolar half maximal inhibitory concentration (IC50) in vitro and potent activity in vivo. Two mechanisms of action for emetine are identified: the inhibition of ZIKV NS5 polymerase activity and disruption of lysosomal function. Emetine also inhibits EBOV entry. Cephaeline, a desmethyl analog of emetine, which may be better tolerated in patients than emetine, exhibits a similar efficacy against both ZIKV and EBOV infections. Hence, emetine and cephaeline offer pharmaceutical therapies against both ZIKV and EBOV infection.

Microglia are the primary resident immune cells of the brain, playing both protective and deleterious roles in neurological diseases, which makes them an enticing therapeutic target. Here we developed a Neural Microglia Integrated Multicellular iPSC-derived Cultured Spheroids (NeuroMIMICS) system that enables measurements of both neural network activity and immune responses using human iPSC-derived microglia, astrocytes, and neurons. We validated microglia functionalities in these neural tri-cultures including phagocytic activity, directed motility, and inflammatory responses. RNAseq analysis revealed a phenotypical acquisition of immune functionality via microglia incorporation, supported by increased cytokine production in spheroids challenged with pathogen-like insults. We then demonstrated that the incorporation of healthy microglia corrected alpha-synuclein A53T-mediated dysfunctional phenotypes in the neural spheroids. This work demonstrates a unique immunocompetent functional neural model that is robust and suited for high-throughput screening, laying the groundwork for its application to accelerate the discovery of new therapeutics for neurological diseases.