Recent characterization of broadly neutralizing antibodies (bnAbs) against influenza virus identified the conserved hemagglutinin (HA) stem as a target for development of universal vaccines and therapeutics. Although several stem bnAbs are being evaluated in clinical trials, antibodies are generally unsuited for oral delivery. Guided by structural knowledge of the interactions and mechanism of anti-stem bnAb CR6261, we selected and optimized small molecules that mimic the bnAb functionality. Our lead compound neutralizes influenza A group 1 viruses by inhibiting HA-mediated fusion in vitro, protects mice against lethal and sublethal influenza challenge after oral administration, and effectively neutralizes virus infection in reconstituted three-dimensional cell culture of fully differentiated human bronchial epithelial cells. Cocrystal structures with H1 and H5 HAs reveal that the lead compound recapitulates the bnAb hotspot interactions.

Using siRNA therapeutics to treat hematologic malignancies has been unsuccessful because blood cancer cells exhibit remarkable resistance to standard transfection methods. Herein, the successful delivery of siRNA therapeutics with a dual-targeted, layer-by-layer nanoparticle (LbL-NP) is reported. The LbL-NP protects siRNA from nucleases in the bloodstream by embedding it within polyelectrolyte layers that coat a polymeric core. The outermost layer consists of hyaluronic acid (a CD44-ligand) covalently conjugated to CD20 antibodies. The CD20/CD44 dual-targeting outer layer provides precise binding to blood cancer cells, followed by receptormediated endocytosis of the LbL-NP. This siRNA delivery platform is used to silence B-cell lymphoma 2 (BCL-2), a pro-survival protein, in vitro and in vivo. The dual-targeting approach significantly enhances internalization of BCL-2 siRNA in lymphoma and leukemia cells, which leads to significant downregulation of BCL-2 expression. Systemic administration of the dual-targeted, siRNA-loaded nanoparticle induces apoptosis and hampers proliferation of blood cancer cells, both in cell culture and in orthotopic non-Hodgkin's lymphoma animal models. These results provide the basis for approaches to targeting blood-borne cancers and other diseases and suggest that LbL nanoassemblies are a promising approach for delivering therapeutic siRNA to hematopoetic cell types that are known to evade transfection by other means.

We have discovered two related chemical series of nonpeptide urotensin-II (U-II) receptor antagonists based on piperazino-phthalimide (5 and 6) and piperazino-isoindolinone (7) scaffolds. These structure types are distinctive from those of U-II receptor antagonist series reported in the literature. Antagonist 7a exhibited single-digit nanomolar potency in rat and human cell-based functional assays, as well as strong binding to the human U-II receptor. In advanced pharmacological testing, 7a blocked the effects of U-II in vitro in a rat aortic ring assay and in vivo in a rat ear-flush model. A discussion of U-II receptor antagonist pharmacophores is presented, and a specifically defined model is suggested from tricycle 13, which has a high degree of conformational constraint.

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