Advances in Computational Methods to Discover New NS2B-NS3 Inhibitors Useful Against Dengue and Zika Viruses.

The Flaviviridae virus family consists of the genera Hepacivirus, Pestivirus, and Flavivirus, with approximately 70 viral types that use arthropods as vectors. Among these diseases, dengue (DENV) and zika virus (ZIKV) serotypes stand out, responsible for thousands of deaths worldwide. Due to the significant increase in cases, the World Health Organization (WHO) declared DENV a potential threat for 2019 due to being transmitted by infected travelers. Furthermore, ZIKV also has a high rate of transmissibility, highlighted in the outbreak in 2015, generating consequences such as Guillain-Barré syndrome and microcephaly. According to clinical outcomes, those infected with DENV can be asymptomatic, and in other cases, it can be lethal. On the other hand, ZIKV has severe neurological symptoms in newborn babies and adults. More serious symptoms include microcephaly, brain calcifications, intrauterine growth restriction, and fetal death. Despite these worrying data, no drug or vaccine is approved to treat these diseases. In the drug discovery process, one of the targets explored against these diseases is the NS2B-NS3 complex, which presents the catalytic triad His51, Asp75, and Ser135, with the function of cleaving polyproteins, with specificity for basic amino acid residues, Lys- Arg, Arg-Arg, Arg-Lys or Gln-Arg. Since NS3 is highly conserved in all DENV serotypes and plays a vital role in viral replication, this complex is an excellent drug target. In recent years, computer-aided drug discovery (CADD) is increasingly essential in drug discovery campaigns, making the process faster and more cost-effective, mainly explained by discovering new drugs against DENV and ZIKV. Finally, the main advances in computational methods applied to discover new compounds against these diseases will be presented here. In fact, molecular dynamics simulations and virtual screening is the most explored approach, providing several hit and lead compounds that can be used in further optimizations. In addition, fragment-based drug design and quantum chemistry/molecular mechanics (QM/MM) provides new insights for developing anti-DENV/ZIKV drugs. We hope that this review offers further helpful information for researchers worldwide and stimulates the use of computational methods to find a promising drug for treating DENV and ZIKV.

Bradykinin-target therapies in SARS-CoV-2 infection: current evidence and perspectives.

Coronavirus disease 2019 (COVID-19) is a potentially fatal disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that preferentially infects the respiratory tract. Bradykinin (BK) is a hypotensive substance that recently emerged as one of the mechanisms to explain COVID-19-related complications. Concerning this, in this review, we try to address the complex link between BK and pathophysiology of COVID-19, investigating the role of this peptide as a potential target for pharmacological modulation in the management of SARS-CoV-2. The pathology of COVID-19 may be more a result of the BK storm than the cytokine storm, and which BK imbalance is a relevant factor in the respiratory disorders caused by SARS-CoV-2 infection. Regarding this, an interesting point of intervention for this disease is to modulate BK signaling. Some drugs, such as icatibant, ecallantide, and noscapine, and even a human monoclonal antibody, lanadelumab, have been studied for their potential utility in COVID-19 by modulating BK signaling. The interaction of the BK pathway and the involvement of cytokines such as IL-6 and IL1 may be key to the use of blockers, even if only as adjuvants. In fact, reduction of BK, mainly DABK, is considered a relevant strategy to improve clinical conditions of COVID-19 patients. In this context, despite the current unproven clinical efficacy, drugs repurposing that block B1 or B2 receptor activation have gained prominence for the treatment of COVID-19 in the world.

Revealing Insights into Natural Products Against mcr-1-Producing Bacteria.

Bacterial resistance has become a major global concern, affecting about 500, 000 individuals in 22 countries. Thus, it is clear that Gram-negative bacteria have been receiving more attention in this scenario. These bacteria perform several resistance mechanisms, such as modifying lipid A from lipopolysaccharides as a product of the mcr-1 gene expression. This gene was initially identified in animals; however, it quickly spread to humans, spreading to 70 countries. Mcr-1 gene attributes resistance to polymyxin B and colistin, which are drugs established as the last alternative to combat Enterobacteriaceae bacteria. Notwithstanding the prevalence and lack of antibiotic therapies for such bacteria, this article aimed to compile information about natural compounds against the resistance attributed by this gene, including the activity of isolated colistin or its associations with other antibiotics. Among the studies that evaluated colistin's synergistic action with other compounds, azidothymidine and isoalantholactone stood out. On the other hand, the paenipeptin 1 analog showed satisfactory activities when associated with other antibiotics. Besides, it is worth mentioning that molecular docking results between ostole and eugenol toward phosphoethanolamine transferase MCR-1 revealed that these compounds could interact with critical amino acid residues for the catalytic action of this enzyme. Based on this, natural agents' role is evident against infections caused by mcr-1-positive bacteria, directly contributing to the development of new effective pharmacotherapies.