Human Immunodeficiency Viruses (HIV-1 and HIV-2) rely upon host-encoded proteins to facilitate their replication. Here we combined genome-wide siRNA analyses with interrogation of human interactome databases to assemble a host-pathogen biochemical network containing 213 confirmed host cellular factors and 11 HIV-1-encoded proteins. Protein complexes that regulate ubiquitin conjugation, proteolysis, DNA damage response and RNA splicing were identified as important modulators of early stage HIV-1 infection. Additionally, over 40 new factors were shown to specifically influence initiation and/or kinetics of HIV-1 DNA synthesis, including cytoskeletal regulatory proteins, modulators of post-translational modification, and nucleic acid binding proteins. Finally, fifteen proteins with diverse functional roles, including nuclear transport, prostaglandin synthesis, ubiquitination, and transcription, were found to influence nuclear import or viral DNA integration. Taken together, the multi-scale approach described here has uncovered multiprotein virus-host interactions that likely act in concert to facilitate early steps of HIV-1 infection.

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Most malaria drug development focuses on parasite stages detected in red-blood cells even though to achieve eradication next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4,000 commercially available compounds with previously demonstrated blood stage activity (IC50 < 1 μM), and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. Our orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 mg/kg) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms.

Hippo signaling represents a tumor suppressor pathway that regulates organ size and tumorigenesis through phosphorylation and inhibition of the transcription coactivator YAP. Here, we show that serum deprivation dramatically induces YAP Ser127 phosphorylation and cytoplasmic retention, independent of cell-cell contact. Through chemical isolation and activity profiling, we identified serum-derived sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) as small molecule activators of YAP. S1P induces YAP nuclear localization through S1P(2) receptor, Rho GTPase activation, and F-actin polymerization, independent of the core Hippo pathway kinases. Bioinformatics studies also showed that S1P stimulation induces YAP target gene expression in mouse liver and human embryonic stem cells. These results revealed potent small molecule regulators of YAP and suggest that S1P and LPA might modulate cell proliferation and tumorigenesis through YAP activation.

Diarrheal disease is responsible for 8.6% of global child mortality. Recent epidemiological studies found the protozoan parasite Cryptosporidium to be a leading cause of pediatric diarrhea with particularly grave impact on infants and immunocompromised individuals. There is neither a vaccine nor effective treatment. We establish a drug discovery process built on scalable phenotypic assays and mouse models that takes advantage of transgenic parasites. Screening a library of compounds with anti-parasitic activity we identified pyrazolopyridines as inhibitors of Cryptosporidium parvum and C. hominis. Oral treatment with the pyrazolopyridine KDU731 results in potent reduction in intestinal infection of immunocompromised mice. Treatment also leads to rapid resolution of diarrhea and dehydration in neonatal calves, a clinical model of cryptosporidiosis that closely resembles human infection. Our results suggest the Cryptosporidium lipid kinase PI(4)K as a target for pyrazolopyridines and warrant further preclinical evaluation of KDU731 as a drug candidate for the treatment of cryptosporidiosis.