Strategies to fight infective agents

Emerging and re-emerging infectious diseases pose a threat worldwide, in this context during my PhD project I have been involved in different studies concerning the investigation of different ways to fight infective agents. In particular the main focus has been the development of inhibitors against the main protease of SARS-CoV-2, in fact, a library of peptide-based inhibitors has been developed, with the aim to accomplish a SAR study that could allow the further development of new antiviral agents with the potential to inhibit the replication not only of SARS-CoV-2 but also of other coronaviruses that have the potential to spillover, or similar viral entities such as enteroviruses. The library of compounds includes 25 new Mpro inhibitors which have been designed, synthesized and their inhibitory activity against the main protease of SARS-CoV-2 has been assessed, giving promising outputs. Moreover the most active compounds have been tested in infected VERO E6 cell line. A further exploration that has been pursued in the context of SARS-CoV-2 Mpro inhibition has been the study of a small library of fragments, in order to further expand the knowledge of the active site pocket and explore new accessible scaffolds for the design of small molecule inhibitors against the main protease of SARS-CoV-2. The development of this limited library of compounds is still in progress as well as the biological evaluation of the first compounds that have been synthesized. The second project in which I have been involved during this PhD project has been the repurposing of in house HDACi with a preventive effect against SARS-CoV-2 infection, based on the knowledge of the entry mechanism of SARS-CoV-2 into the host cells, which is achieved through the binding of the viral particles to the host receptor ACE2, whose expression has been correlated with HDAC modulation. For this reason two selective HDACi developed by the research group have been repurposed for their biological evaluation in terms of prophylactic activity of these compounds towards ACE2-mediated entry coronaviruses. The compounds have thus been synthesized and the biological evaluation is ongoing. A further study that has been carried out during this PhD project has been the development of monkeypox VP37 inhibitors. In particular, taking inspiration from the approved anti-viral agent tecovirimat, which is an inhibitor of the VP37 protein of monkeypox, a SAR study has been carried out, exploring different moieties for the cap group that interacts with the external surface of the active site and of the linker unit of these compounds. The compounds that have been synthesized so far have been evaluated from a biological point of view, for their inhibitory potency in infected cells, affording promising results, Finally, among the infective agents with high morbidity and mortality note to mention surely are the Pseudomonas aeruginosa acute and chronic infections in patients affected by cystic fibrosis. During this project, which has been recently published, a family of modulators of the virulence factors within the biofilm of Pa has been developed and the evaluation of the inhibition of the biofilm, and the modulation of pyoverdine and pyocyanin has been assessed with promising results, confirming the efficacy of these compounds.