|M.Sc Student||Einav Tayeb-Fligelman|
|Subject||Design and Synthesis of Small and Flexible Aminoglycoside|
Based Scaffolds for Treatment of Human Genetic
|Department||Department of Chemistry||Supervisor||Full Professor Baasov Timor|
|Full Thesis text|
Nonsense mutations result in the formation of truncated proteins that in many cases might manifest as fatal diseases. For many of these diseases there is presently no effective treatment other than symptomatic. Studies conducted during the last few decades, have demonstrated the ability of certain aminoglycosides to participate in the eukaryotic translation process in a way that enables the ribosome to readthrough the nonsense codon, and thereby form, to some extent, full length functional proteins. However, the use of aminoglycosides for the treatment of genetic diseases suffers serious disadvantages, a fact that raise the need to optimize aminoglycosides-activity as readthrough inducers.
The goal of this work was to design, synthesize and evaluate the activity of small and flexible aminoglycoside-based scaffolds possessing good readthrough activity, low toxicity and high selectivity to the eukaryotic ribosome as well as to the readthrough mechanism as oppose to other mechanisms promoting inhibition in protein translation.
Synthesis of these flexible scaffolds included the selective cleavage of ring I (A), ring II (NB110), as well as both rings (NB116) of our laboratory's well established scaffold Paromamine, in addition to replacing its ring II with an acyclic moiety comprising a new chiral center (NB148 and NB149). While NB110 exhibited no readthrough activity and compound A decomposed, NB116, NB149 and mostly NB148 demonstrated similar to higher readthrough activity than that of Paromamine, with significantly reduced inhibition of translation. More importantly, when subjected to IC50 tests, the two diastereomers, NB148 and NB149, were found to be tremendously poor inhibitors of prokaryotic and eukaryotic ribosomes.
The fact that we were able to increase readthrough activity and at the same time decrease inhibition of translation, encourage us to believe that by enhancing the flexibility of our scaffolds we created “smart” and small molecules that display a mechanistic preference toward the readthrough mechanism rather than other mechanisms that promote inhibition of translation, a preference that may be expressed in much lower levels of toxicity. With these findings we have opened a new direction in the creation of aminoglycoside-based readthrough inducers that may offer promise in the treatment of human genetic diseases.