Amyotrophic lateral sclerosis (ALS) is a devastating motor neuroncopper, zinc superoxide dismutase ͉ motor neuron ͉ neurodegeneration

We present an unconventional approach to antiviral drug discovery, which is used to identify potent small molecules against rabies virus. First, we conceptualized viral capsid assembly as occurring via a hostcatalyzed biochemical pathway, in contrast to the classical view of capsid formation by self-assembly. This suggested opportunities for antiviral intervention by targeting previously unappreciated catalytic host proteins, which were pursued. Second, we hypothesized these host proteins to be components of heterogeneous, labile, and dynamic multi-subunit assembly machines, not easily isolated by specific target protein-focused methods. This suggested the need to identify active compounds before knowing the precise protein target. A cell-free translation-based small molecule screen was established to recreate the hypothesized interactions involving newly synthesized capsid proteins as host assembly machine substrates. Hits from the screen were validated by efficacy against infectious rabies virus in mammalian cell culture. Used as affinity ligands, advanced analogs were shown to bind a set of proteins that effectively reconstituted drug sensitivity in the cell-free screen and included a small but discrete subfraction of cellular ATP-binding cassette family E1 (ABCE1), a host protein previously found essential for HIV capsid formation. Taken together, these studies advance an alternate view of capsid formation (as a host-catalyzed biochemical pathway), a different paradigm for drug discovery (whole pathway screening without knowledge of the target), and suggest the existence of labile assembly machines that can be rendered accessible as next-generation drug targets by the means described.assembly intermediate | viral-host interaction | whole pathway screen | drug discovery paradigm | protein heterogeneity

Antiviral compounds displaying remarkable features have been identified by an unconventional drug screen and advanced through animal validation. Efficacy is observed against the six viral families causing most human respiratory viral disease, irrespective of strain, including both influenza (FLUV) and SARS-CoV-2, with cell culture EC50 at or below 100 nM. Survival benefit is demonstrated in pigs against another member of family Coronaviridae, porcine epidemic diarrhea virus (PEDV), and shown equally effective in mild and severe disease. Respiratory syncytial virus (RSV) titer is reduced by drug treatment in cotton rats. A substantial barrier to viral resistance is demonstrated for FLUV. Drug resin affinity chromatography (DRAC) reveals a novel drug target: a multi-protein complex (MPC) formed transiently, in an energy-dependent fashion, and composed of host proteins implicated in both viral lifecycles and manipulation of innate immunity. The protein composition of this host MPC is modified upon viral infection, with increase or decrease of some proteins and appearance or complete loss of others. Valosin-containing protein, also known as Transitional endoplasmatic reticulum ATPase (VCP/p97), is present in the target MPC of uninfected cells and significantly increased in both FLUV and CoV infection. SQSTM1/p62, a key regulator of the autophagy pathway of innate immunity whose dysfunction is implicated in cytokine storm, is i) found in the target MPC from uninfected cells, ii) diminished in DRAC eluates by infection, and iii) restored by drug treatment of infected cells. 14-3-3 is one of likely several proteins that comprise the drug-binding site. Advanced compounds with improved pharmacokinetic (PK) properties and lung exposure are approaching criteria for a Target Product Profile. We propose these novel drug targets to comprise a previously unappreciated molecular basis for homeostasis that is modified by viruses to allow exploitation for viral propagation and is restored by treatment with the therapeutic compounds presented. This discovery has transformative implications for treatment of respiratory viral-related disease, applicable to everything from seasonal FLUV to COVID-19 and future novel respiratory viruses, due to the pan-family nature of drug activity and barrier to resistance development.

Two structurally-unrelated small molecule chemotypes, represented by compounds PAV-617 and PAV-951, with antiviral activity in cell culture against monkeypox virus (MPXV) and human immunodeficiency virus (HIV) respectively, were studied for anti-cancer efficacy. Each exhibited apparent pan-cancer cytotoxicity, reasonable pharmacokinetics, and non-toxicity in mice at active concentrations. Anti-tumor properties of each compound were validated in mouse xenografts against A549 human lung cancer. The targets of these compounds are unconventional: each binds to a different transient, energy-dependent multi-protein complex containing the protein KAP-1(TRIM28), an allosteric modulator known to broadly regulate mechanisms underlying viral and nonviral disease states including cancer. Treatment with these compounds alters the target multi-protein complexes in a manner consistent with allosteric modulation as their mechanism of action. These compounds appear to remove a block, crucial for cancer survival and progression, on the homeostatic linkage of uncontrolled cellular proliferation to apoptosis. These compounds may provide starting points for development of next-generation non-toxic, cancer therapeutics.

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