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The emerging epidemic of drug resistance places the development of efficacious and safe antibiotics in the spotlight of current research. Here, we report the design of next-generation aminoglycosides. Discovery efforts were driven by rational synthesis focusing on 4′ alkylations of the aminoglycoside paromomycin, with the goal to alleviate the most severe and disabling side effect of aminoglycosides—irreversible hearing loss. Compounds were evaluated for target activity in in vitro ribosomal translation assays, antibacterial potency against selected pathogens, cytotoxicity against mammalian cells, and in vivo ototoxicity. The results of this study produced potent compounds with excellent selectivity at the ribosomal target, promising antibacterial activity, and little, if any, ototoxicity upon chronic administration. The favorable biocompatibility profile combined with the promising antibacterial activity emphasizes the potential of next-generation aminoglycosides in the treatment of infectious diseases without the risk of ototoxicity., IMPORTANCE The ever-widening epidemic of multidrug-resistant infectious diseases and the paucity of novel antibacterial agents emerging from modern screening platforms mandate the reinvestigation of established drugs with an emphasis on improved biocompatibility and overcoming resistance mechanisms. Here, we describe the preparation and evaluation of derivatives of the established aminoglycoside antibiotic paromomycin that effectively remove its biggest deficiency, ototoxicity, and overcome certain bacterial resistance mechanisms.

Clinical use of 2-deoxystreptamine aminoglycoside antibiotics, which target the bacterial ribosome, is compromised by adverse effects related to limited drug selectivity. Here we present a series of 4′,6′-O-acetal and 4′-O-ether modifications on glucopyranosyl ring I of aminoglycosides. Chemical modifications were guided by measuring interactions between the compounds synthesized and ribosomes harbouring single point mutations in the drug-binding site, resulting in aminoglycosides that interact poorly with the drug-binding pocket of eukaryotic mitochondrial or cytosolic ribosomes. Yet, these compounds largely retain their inhibitory activity for bacterial ribosomes and show antibacterial activity. Our data indicate that 4′-O-substituted aminoglycosides possess increased selectivity towards bacterial ribosomes and little activity for any of the human drug-binding pockets., Aminoglycoside antibiotics target the ribosome but their limited selectivity for the bacterial ribosome can cause side effects in humans. Here, the authors synthesize 4′-O-ether or 4′,6′-O-acetal modifications and show that these compounds possess increased selectivity against bacterial ribosomes.

Background There are a surprising number of interconnecting fibre tracts linking the two cerebral hemispheres, the largest of these being the corpus callosum, but the hippocampal and anterior commissures are also sizable structures. The posterior commissure bridges the upper part of the midbrain and lies adjacent to the posterior end of the third ventricle. Hydrocephalus is known to cause thinning of the corpus callosum but its effect on the other interconnections has not been extensively investigated. On day E18 at the onset of hydrocephalus in the HTx rat development of the corpus callosum is incomplete. The observed thinning of the corpus callosum in fetal onset hydrocephalus is likely to deprive the hemispheres of interconnections. This study was carried out to investigate the effect of hydrocephalus on the other interconnecting fibre tracts and in particular whether adaptive changes occur in any of them.