The Plasmodium proteasome is an emerging antimalarial target due to its essential role in all the major life cycle stages of the parasite and its contribution to the establishment of resistance to artemisinin (ART)-based therapies. However, because of a similarly essential role for the host proteasome, the key property of any antiproteasome therapeutic is selectivity. Several parasite-specific proteasome inhibitors have recently been reported, however, their selectivity must be improved to enable clinical development. Here we describe screening of diverse libraries of non-natural synthetic fluorogenic substrates to identify determinants at multiple positions on the substrate that produce enhanced selectivity. We find that selection of an optimal electrophilic "warhead" is essential to enable high selectivity that is driven by the peptide binding elements on the inhibitor. We also find that host cell toxicity is dictated by the extent of coinhibition of the human β2 and β5 subunits. Using this information, we identify compounds with over 3 orders of magnitude selectivity for the parasite enzyme. Optimization of the pharmacological properties resulted in molecules that retained high potency and selectivity, were soluble, sufficiently metabolically stable and orally bioavailable. These molecules are highly synergistic with ART and can clear parasites in a mouse model of infection, making them promising leads as antimalarial drugs.

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All bacteria display surface-exposed glycans that can play an important role in their interaction with the host and in select cases mimic the glycans found on host cells, an event called molecular or glycan mimicry. In this review, we highlight the key bacteria that display human glycan mimicry and provide an overview of the involved glycan structures. We also discuss the general trends and outstanding questions associated with human glycan mimicry by bacteria. Finally, we provide an overview of several techniques that have emerged from the discipline of chemical glycobiology, which can aid in the study of the composition, variability, interaction and functional role of these mimicking glycans.

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Purpose: Accurate dosimetry is essential in radioembolization. To this purpose, an automatic protocol for healthy liver dosimetry based on dual isotope (DI) SPECT imaging, combining holmium-166 (166 Ho)-microspheres, and technetium-99 m (99m Tc)-colloid was developed: 166 Ho-microspheres used as scout and therapeutic particles, and 99m Tc-colloid to identify the healthy liver. DI SPECT allows for an automatic and accurate estimation of absorbed doses, introducing true personalized dosimetry. However, photon crosstalk between isotopes can compromise image quality. This study investigates the effect of 99m Tc downscatter on 166 Ho dosimetry, by comparing 166 Ho-SPECT reconstructions of patient scans acquired before (166 Hoonly) and after additional administration of 99m Tc-colloid (166 Ho-DI). Methods: The 166 Ho-only and 166 Ho-DI scans were performed in short succession by injecting 99m Tc-colloid on the scanner table. To compensate for 99m Tc downscatter, its influence was accounted for in the DI image reconstruction using energy window-based scatter correction methods. The qualitative assessment was performed by independent blinded comparison by two nuclear medicine physicians assessing 65 pairs of SPECT/CT. Inter-observer agreement was tested by Cohen's kappa coefficient. For the quantitative analysis, two volumes of interest within the liver, VOI TUMOR , and VOI HEALTHY were manually delineated on the 166 Ho-only reconstruction and transferred to the co-registered 166 Ho-DI reconstruction. Absorbed dose within the resulting VOIs, and in the lungs (VOI LUNGS), was calculated based on the administered therapeutic activity. Results: The qualitative assessment showed no distinct clinical preference for either 166 Ho-only or 166 Ho-DI SPECT (kappa = 0.093). Quantitative analysis indicated that the mean absorbed dose difference between 166 Ho-DI and 166 Ho-only was − 2.00 ± 2.84 Gy (median 27 Gy; p value < 0.00001), − 5.27 ± 8.99 Gy (median 116 Gy; p value = 0.00035), and 0.80 ± 1.08 Gy (median 3 Gy; p value < 0.00001) for VOI HEALTHY, VOI TUMOR, and VOI LUNGS , respectively. The corresponding Pearson's correlation coefficient between 166 Ho-only and 166 Ho-DI for absorbed dose was 0.97, 0.99, and 0.82, respectively. Conclusion: The DI protocol enables automatic dosimetry with undiminished image quality and accuracy.