Mice Doubly-Deficient in Lysosomal Hexosaminidase A and Neuraminidase 4 Show Epileptic Crises and Rapid Neuronal Loss

Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HexA gene coding for the α-subunit of lysosomal β-hexosaminidase A, which converts GM2 to GM3 ganglioside. Hexa−/− mice, depleted of β-hexosaminidase A, remain asymptomatic to 1 year of age, because they catabolise GM2 ganglioside via a lysosomal sialidase into glycolipid GA2, which is further processed by β-hexosaminidase B to lactosyl-ceramide, thereby bypassing the β-hexosaminidase A defect. Since this bypass is not effective in humans, infantile Tay-Sachs disease is fatal in the first years of life. Previously, we identified a novel ganglioside metabolizing sialidase, Neu4, abundantly expressed in mouse brain neurons. Now we demonstrate that mice with targeted disruption of both Neu4 and Hexa genes (Neu4−/−;Hexa−/−) show epileptic seizures with 40% penetrance correlating with polyspike discharges on the cortical electrodes of the electroencephalogram. Single knockout Hexa−/− or Neu4−/− siblings do not show such symptoms. Further, double-knockout but not single-knockout mice have multiple degenerating neurons in the cortex and hippocampus and multiple layers of cortical neurons accumulating GM2 ganglioside. Together, our data suggest that the Neu4 block exacerbates the disease in Hexa−/− mice, indicating that Neu4 is a modifier gene in the mouse model of Tay-Sachs disease, reducing the disease severity through the metabolic bypass. However, while disease severity in the double mutant is increased, it is not profound suggesting that Neu4 is not the only sialidase contributing to the metabolic bypass in Hexa−/− mice

The Soft Power of Anglia: British Cold War Cultural Diplomacy in the USSR

This article contributes to the growing literature on the cultural Cold War through an exploration of the British national projection magazine Anglia, produced by the Foreign Office for distribution in the USSR from 1962 to 1992. As well as drawing attention to the significance of national magazines in general, the article sheds light on Britain's distinctive approach to propaganda and cultural diplomacy during the Cold War. It considers why the magazine was set up and endured for so long, despite considerable reservations about its value. It examines how Britain was projected in a manner that accorded with British understandings about the need for ‘subtle’ propaganda. Finally, it addresses the question of the magazine's impact in the USSR

Architecture and hydration of the arginine‐binding site of neuropilin‐1

Neuropilin-1 (NRP1) is a transmembrane co-receptor involved in binding interactions with variety of ligands and receptors, including receptor tyrosine kinases. Expression of NRP1 in several cancers correlates with cancer stages and poor prognosis. Thus, NRP1 has been considered a therapeutic target and is the focus of multiple drug discovery initiatives. Vascular endothelial growth factor (VEGF) binds to the b1 domain of NRP1 through interactions between the C-terminal arginine of VEGF and residues in the NRP1 binding site including Tyr297, Tyr353, Asp320, Ser346, and Thr349. We obtained several complexes of the synthetic ligands and the NRP1-b1 domain and used X-ray crystallography and computational methods to analyze atomic details and hydration profile of this binding site. We observed side chain flexibility for Tyr297 and Asp320 in the 6 new high resolution crystal structures of arginine analogues bound to NRP1. In addition, we identified conserved water molecules in binding site regions which can be targeted for drug design. The computational prediction of the VEGF ligand-binding site hydration map of NRP1 was in agreement with the experimentally-derived, conserved hydration structure. Displacement of certain conserved water molecules by a ligand's functional groups may contribute to binding affinity, whilst other water molecules perform as protein - ligand bridges. Our report provides a comprehensive description of the binding site for the peptidic ligands' C-terminal arginines in the b1 domain of NRP1, highlights the importance of conserved structural waters in drug design, and validates the utility of the computational hydration map prediction method in the context of neuropilin. This article is protected by copyright. All rights reserved

Small Molecule Neuropilin‑1 Antagonists Combine Antiangiogenic and Antitumor Activity with Immune Modulation through Reduction of Transforming Growth Factor Beta (TGFβ) Production in Regulatory T‑Cells

We report the design, synthesis, and biological evaluation of some potent small-molecule neuropilin-1 (NRP1) antagonists. NRP1 is implicated in the immune response to tumors, particularly in Treg cell fragility, required for PD1 checkpoint blockade. The design of these compounds was based on a previously identified compound EG00229. The design of these molecules was informed and supported by X-ray crystal structures. Compound <b>1</b> (EG01377) was identified as having properties suitable for further investigation. Compound <b>1</b> was then tested in several in vitro assays and was shown to have antiangiogenic, antimigratory, and antitumor effects. Remarkably, <b>1</b> was shown to be selective for NRP1 over the closely related protein NRP2. In purified Nrp1⁺, FoxP3⁺, and CD25⁺ populations of Tregs from mice, <b>1</b> was able to block a glioma-conditioned medium-induced increase in TGFβ production. This comprehensive characterization of a small-molecule NRP1 antagonist provides the basis for future in vivo studies