Unlocking G-Quadruplexes as Antiviral Targets

Guanine-rich DNA and RNA sequences can fold into noncanonical nucleic acid structures called G-quadruplexes (G4s). Since the discovery that these structures may act as scaffolds for the binding of specific ligands, G4s aroused the attention of a growing number of scientists. The versatile roles of G4 structures in viral replication, transcription, and translation suggest direct applications in therapy or diagnostics. G4-interacting molecules (proteins or small molecules) may also affect the balance between latent and lytic phases, and increasing evidence reveals that G4s are implicated in generally suppressing viral processes, such as replication, transcription, translation, or reverse transcription. In this review, we focus on the discovery of G4s in viruses and the role of G4 ligands in the antiviral drug discovery process. After assessing the role of viral G4s, we argue that host G4s participate in immune modulation, viral tumorigenesis, cellular pathways involved in virus maturation, and DNA integration of viral genomes, which can be potentially employed for antiviral therapeutics. Furthermore, we scrutinize the impediments and shortcomings in the process of studying G4 ligands and drug discovery. Finally, some unanswered questions regarding viral G4s are highlighted for prospective future projects. SIGNIFICANCE STATEMENT: G-quadruplexes (G4s) are noncanonical nucleic acid structures that have gained increasing recognition during the last few decades. First identified as relevant targets in oncology, their importance in virology is now increasingly clear. A number of G-quadruplex ligands are known: viral transcription and replication are the main targets of these ligands. Both viral and cellular G4s may be targeted; this review embraces the different aspects of G-quadruplexes in both host and viral contexts.

Passionflower in the treatment of opiates withdrawal: a double-blind randomized controlled trial

OBJECTIVE

Clonidine-based therapies have been utilized as the main protocol for opiate detoxification for several years. However, detoxification with clonidine has its limitations, including lack of efficacy for mental symptoms. Accumulating evidence shows the efficacy of Passiflora incarnata extract in the management of anxiety. In our continuing study of traditional medicines, which have neurotropic effects, this plant had an anxiolytic effect, which may be used as an adjuvant agent in the detoxification of opiates by clonidine. We present the results of a double-blind randomized controlled trial of clonidine plus passiflora extract vs. clonidine plus placebo in the outpatient detoxification of 65 opiates addicts.

METHODS

A total of 65 opiates addicts were assigned randomly to treatment with passiflora extract plus clonidine tablet or clonidine tablet plus placebo drop during a 14-day double-blind clinical trial. All patients met the DSM IV criteria for opioid dependence. The fixed daily dose was 60 drops of passiflora extract and a maximum daily dose of 0.8 mg of clonidine administered in three divided doses. The severity of the opiate withdrawal syndrome was measured on days 0, 1, 2, 3, 4, 7 and 14 using the Short Opiate Withdrawal Scale (SOWS).

CONCLUSION

Both protocols were equally effective in treating the physical symptoms of withdrawal syndromes. However, the passiflora plus clonidine group showed a significant superiority over clonidine alone in the management of mental symptoms. These results suggested that passiflora extract may be an effective adjuvant agent in the management of opiate withdrawal. However, a larger study to confirm our results is warranted.