Giulia Lottini

A small library of 23 pyrrole-based tricyclic derivatives bearing bulky amine moieties was synthesized, and all were evaluated for their antiviral activities against ZIKV and SARS-CoV. Three compounds, derivatives 2g, 2h and 2j, elicited interesting activity against ZIKV: compound 2g, containing a bornylamine residue, showed the best activity against Huh-7 cells with EC₅₀ and CC₅₀ values of 0.4 μM and 230.5 μM, respectively, and a Selectivity Index (SI) of 501. All three compounds reduce ZIKV yield primarily by impairing viral protein.

Human DEAD-box helicase 3 (DDX3) is a multifunctional RNA helicase implicated in mRNA unwinding and the regulation of gene expression. While DDX3 has been extensively studied in the context of RNA virus replication, its role in DNA virus replication remains less understood. In this study, we explore the involvement of DDX3 in the life cycle of Herpes Simplex Virus type 2 (HSV-2), a double-stranded DNA virus. Silencing of DDX3 expression with siRNA significantly impaired HSV-2 replication, indicating that DDX3 supports viral propagation. Unexpectedly, HSV-2 infection led to a marked reduction in cellular DDX3 protein levels during in vitro replication in human cells, particularly at 24 h post-infection, corresponding to the peak of viral production. Notably, this decrease was not accompanied by a reduction in DDX3 mRNA levels, nor was it prevented by proteasome inhibition, suggesting an alternative mechanism of DDX3 depletion. Further analysis revealed substantial amounts of DDX3 protein within HSV-2 virions, supporting the hypothesis that DDX3 is packaged into viral particles during replication. We propose that HSV-2 exploits host DDX3 by incorporating it into progeny virions to facilitate early stages of infection in newly infected cells. However, no evidence linking DDX3 to the assembly process of HSV-2 particles was found. These findings expand the known functional repertoire of DDX3 and highlight its potential as a host factor co-opted by DNA viruses, suggesting a broader relevance in antiviral strategies.

Fibroblast growth factors (FGFs) are a family of proteins that play a crucial role in the development and maintenance of various tissues in the body. There are three function‐al groups of FGFs: canonical FGFs (cFGFs), intracellularly retained FGFs, and metabolic (also called endocrine) FGFs. cFGFs are secreted and act in an autocrine/paracrine fashion to regulate differentiation during foetal development, as well as tissue repair in adults. Recent studies have also begun to unravel the role of cFGFs during viral infections, suggesting that FGF‐2 and other canonical FGFs may have an important virus‐specific role, also by the regulation of the immune response. Because dysregulation in the FGF pathways is pivotal in cancer development, FGFs are the target of many anticancer drugs. These drugs may be repurposed to treat viral infection, since dysregulation of FGF signalling has been implicated in the pathogenesis of viral infections, such as hepatitis C. Overall, the role of cFGFs during viral infection is an underrepresented area of current research. This review focuses on overviewing the effects of canonical FGFs during infection by different viruses. Many studies highlight that the effects of FGFs during viral infection may be complex and context‐dependent. While there is evidence to suggest that FGFs may have a beneficial impact on the immune response and tissue repair during viral infection, further studies are needed to fully understand the mechanisms underlying these effects and to determine in what cases FGFs could be targeted as a therapeutic approach for viral infection.