Protein and Peptide Substances in the Treatment of Respiratory Syncytial Infection: Current State

Respiratory syncytial virus infection (RSVI) is an acute medical and social problem in many countries globally. Infection is most dangerous for infants under one year old and the elderly. Despite its epidemiological relevance, only two drugs are registered for clinical use against RSVI: ribavirin (approved in a limited number of countries due to side effects) and palivizumab (Synagis), which is intended only for the prevention, but not the treatment, of infection. Currently, various research groups are searching for new drugs against RSV, with three main areas of research: small molecules, polymeric drugs (proteins and peptides), and plant extracts. This review is devoted to currently developed protein and peptide anti-RSV drugs

Activity of Ingavirin (6-[2-(1H-Imidazol-4-yl)ethylamino]-5-oxo-hexanoic Acid) Against Human Respiratory Viruses in in Vivo Experiments

Respiratory viral infections constitute the most frequent reason for medical consultations in the World. They can be associated with a wide range of clinical manifestations ranging from self-limited upper respiratory tract infections to more devastating conditions such as pneumonia. In particular, in serious cases influenza A leads to pneumonia, which is particularly fatal in patients with cardiopulmonary diseases, obesity, young children and the elderly. In the present study, we show a protective effect of the low-molecular weight compound Ingavirin (6-[2-(1H-imidazol-4-yl)ethylamino]-5-oxohexanoic acid) against influenza A (H1N1) virus, human parainfluenza virus and human adenovirus infections in animals. Mortality, weight loss, infectious titer of the virus in tissues and tissue morphology were monitored in the experimental groups of animals. The protective action of Ingavirin was observed as a reduction of infectious titer of the virus in the lung tissue, prolongation of the life of the infected animals, normalization of weight dynamics throughout the course of the disease, lowering of mortality of treated animals compared to a placebo control and normalization of tissue structure. In case of influenza virus infection, the protective activity of Ingavirin was similar to that of the reference compound Tamiflu. Based on the results obtained, Ingavirin should be considered as an important part of anti-viral prophylaxis and therapy

Monoterpene-Containing Substituted Coumarins as Inhibitors of Respiratory Syncytial Virus (RSV) Replication

Respiratory syncytial virus (RSV) is a critical cause of infant mortality. However, there are no vaccines and adequate drugs for its treatment. We showed, for the first time, that O-linked coumarin–monoterpene conjugates are effective RSV inhibitors. The most potent compounds are active against both RSV serotypes, A and B. According to the results of the time-of-addition experiment, the conjugates act at the early stages of virus cycle. Based on molecular modelling data, RSV F protein may be considered as a possible target

Inhibition of Cyclin-Dependent Kinases 8/19 Restricts Bacterial and Virus-Induced Inflammatory Responses in Monocytes

Hyperactivation of the immune system remains a dramatic, life-threatening complication of viral and bacterial infections, particularly during pneumonia. Therapeutic approaches to counteract local and systemic outbreaks of cytokine storm and to prevent tissue damage remain limited. Cyclin-dependent kinases 8 and 19 (CDK8/19) potentiate transcriptional responses to the altered microenvironment, but CDK8/19 potential in immunoregulation is not fully understood. In the present study, we investigated how a selective CDK8/19 inhibitor, Senexin B, impacts the immunogenic profiles of monocytic cells stimulated using influenza virus H1N1 or bacterial lipopolysaccharides. Senexin B was able to prevent the induction of gene expression of proinflammatory cytokines in THP1 and U937 cell lines and in human peripheral blood-derived mononuclear cells. Moreover, Senexin B substantially reduced functional manifestations of inflammation, including clustering and chemokine-dependent migration of THP1 monocytes and human pulmonary fibroblasts (HPF)

Discovery of N-Containing (-)-Borneol Esters as Respiratory Syncytial Virus Fusion Inhibitors

Respiratory syncytial virus (RSV) causes acute respiratory infections, thus, posing a serious threat to the health of infants, children, and elderly people. In this study, we have discovered a series of potent RSV entry inhibitors with the (-)-borneol scaffold. The active compounds 3b, 5a, 5c, 7b, 9c, 10b, 10c, and 14b were found to exhibit activity against RSV A strain A2 in HEp-2 cells. The most active substances, 3b (IC50 = 8.9 μM, SI = 111) and 5a (IC50 = 5.0 μM, SI = 83), displayed more potency than the known antiviral agent Ribavirin (IC50 = 80.0 μM, SI = 50). Time-of-addition assay and temperature shift studies demonstrated that compounds 3b, 5a, and 6b inhibited RSV entry, probably by interacting with the viral F protein that mediated membrane fusion, while they neither bound to G protein nor inhibited RSV attachment to the target cells. Appling procedures of molecular modeling and molecular dynamics, the binding mode of compounds 3b and 5a was proposed. Taken together, the results of this study suggest (-)-borneol esters to be promising lead compounds for developing new anti-RSV agents

Cationic Perylene Antivirals with Aqueous Solubility for Studies In Vivo

Perylene-based compounds are attracting significant attention due to their high broad-spectrum antiviral activity against enveloped viruses. Despite unambiguous results of in vitro studies and high selectivity index, the poor water solubility of these compounds prevented in vivo evaluation of their antiviral properties. In this work, we synthesized a series of compounds with a perylene pharmacophore bearing positively charged substituents to improve the aqueous solubility of this unique type of antivirals. Three types of charged groups were introduced: (1) quaternary morpholinium salts (3a–b); (2) a 2′-O-l-valinyl-uridine hydrochloride residue (8), and (3) a 3-methylbenzothiazolium cation (10). The synthesized compounds were evaluated based both on antiviral properties in vitro (CHIKV, SARS-CoV-2, and IAV) and on solubility in aqueous media. Compound 10 has the greatest aqueous solubility, making it preferable for pre-evaluation by intragastrical administration in a mouse model of lethal influenza pneumonia. The results indicate that the introduction of a positively charged group is a viable strategy for the design of drug candidates with a perylene scaffold for in vivo studies

Identification and Study of the Action Mechanism of Small Compound That Inhibits Replication of Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is known to cause annual epidemics of respiratory infections; however, the lack of specific treatment options for this disease poses a challenge. In light of this, there has been a concerted effort to identify small molecules that can effectively combat RSV. This article focuses on the mechanism of action of compound K142, which was identified as a primary screening leader in the earlier stages of the project. The research conducted demonstrates that K142 significantly reduces the intensity of virus penetration into the cells, as well as the formation of syncytia from infected cells. These findings show that the compound’s interaction with the surface proteins of RSV is a key factor in its antiviral activity. Furthermore, pharmacological modeling supports that K142 effectively interacts with the F-protein. However, in vivo studies have shown only weak antiviral activity against RSV infection, with a slight decrease in viral load observed in lung tissues. As a result, there is a need to enhance the bioavailability or antiviral properties of this compound. Based on these findings, we hypothesize that further modifications of the compound under study could potentially increase its antiviral activity