Antiviral drug development for treatment of acute and chronic viral infections
Creators: name: DRAGONI, FILIPPO
Publisher: name: Universit� degli Studi di Siena
Year: 2021

description: Background
Viruses are aetiologic agents of several human infectious diseases, which can be distinguished into acute and chronic. Among the agents causing acute infections, arboviruses, such as Dengue (DENV), West Nile (WNV) and Zika (ZIKV) Viruses, have increasingly spread worldwide. Moreover, the newly discovered Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), causing the COVID-19 disease, is responsible for an incredibly quantity of infections and deaths. Conversely, the Human Immunodeficiency Virus (HIV-1) is a well-known pathogen able to cause chronic latent infection, but it still represents a global public health concern.
The main strategy for combating viral infections is a combination of vaccination and antiviral drugs. However, vaccines are available only for a minority of viral pathogens, thus the demand for new antiviral strategies has significantly increased. Anyway, the screening of candidate compounds requires the assessment of their antiviral effects in vitro.

Results and discussion
An easy-to-perform and fast flavivirus immunodetection assay (IA) was developed to determine antiviral activity of promising compounds against ZIKV and DENV, able to distinguish between the inhibitory effect of molecules targeting the early and post-budding phases of viral replication cycle.

Considering that the activity of sofosbuvir, a nucleotide analog licensed for HCV infection, has been documented against different flaviviruses, we investigated whether it may exert an activity also against WNV. We determined for the first time the antiviral activity of sofosbuvir against WNV in both cell-based and enzymatic assays. Moreover, in vitro selection and molecular docking experiments indicated that HCV and WNV share a similar sofosbuvir resistance pattern.

The ?ORIGINALE CHEMIAE in Antiviral Strategy? project aims to identify promising broad-spectrum antivirals by taking advantage of the Multi-Component Chemistry strategy. Antiviral activity of molecules was determined in vitro against DENV, WNV, HIV-1 and SARS-CoV-2. Two compounds were able to inhibit viral replication against two different families of viruses (DENV/WNV and SARS-CoV-2), and two compounds were able to inhibit viral replication against viruses with remarkable differences in their replication cycle (DENV/WNV and HIV-1).

At the beginning of the pandemic, an Italian network named SCIRE (SARS-CoV-2 Italian Research Enterprise) was created in order to trace SARS-COV-2 evolution. By NGS whole genome sequencing, it was defined that the initial outbreak in Italy was mainly attributable to the SARS-CoV-2 lineage B.1 and to its uncontrolled circulation for an estimated period of 4 weeks.

Developing strategies to eradicate chronic HIV-1 infection are a high priority. Recently, it was hypothesized that maraviroc (MVC), may exert a latency reversing effect in addition to its antiviral activity. Thus, the MVC-mediated HIV-1 induction was explored. An increased HIV-1 expression was detected at the highest MVC concentration in two of the three cell line models tested. In ex vivo CD4 T cells, MVC-mediated induction was detected sparsely on individual samples. Such evidences suggest the role of MVC as a weak latency reversing agent of the HIV-1 provirus induction.

Conclusions
Control of viral infections is a continuous challenge for public health. The development of effective antiviral compounds could be reasonably the key to halt the spread or to mitigate severe clinical manifestations of acute viral diseases. Moreover, antiviral therapy is essential to the maintenance of undetectable viral loads in chronic infection. Furthermore, developing of compounds able to exert a reversal latency effect may be a remarkable benefit in exacerbate chronic viral infections. 
In conclusion, the key concept of this thesis is to underline the strong need, and partially participate, in enhancing antiviral therapies strategies to counteract the burden of both acute and chronic viral diseases.