4′-Fluorouridine is an oral antiviral that blocks respiratory syncytial virus and SARS-CoV-2 replication

Preparing antiviral defenses Antiviral drugs are an important tool in the battle against COVID-19. Both remdesivir and molnupiravir, which target the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase, were first developed against other RNA viruses. This highlights the importance of broad-spectrum antivirals that can be rapidly deployed against related emerging pathogens. Sourimant et al . used respiratory syncytial virus (RSV) as a primary indication in identifying further drugs that target the polymerase enzyme of RNA viruses. The authors explored derivatives of molnupiravir and identified 4′ fluorouridine (EIDD-2749) as an inhibitor of the polymerase of RSV and SARS-CoV-2. This drug can be delivered orally and was effective against RSV in mice and SARS-CoV-2 in ferrets. —VV

ATP6V1B2 and IFI27 and their intrinsic functional genomic characteristics associated with SARS-CoV-2

Genes functionally associated with SARS-CoV-2 and genes functionally related to COVID-19 disease can be different, whose distinction will become the first essential step for successfully fighting against the COVID-19 pandemic. Unfortunately, this first step has not been completed in all biological and medical research. Using a newly developed max-competing logistic classifier, two genes, ATP6V1B2 and IFI27, stand out to be critical in transcriptional response to SARS-CoV-2 with differential expressions derived from NP/OP swab PCR. This finding is evidenced by combining these two genes with one another gene in predicting disease status to achieve better-indicating power than existing classifiers with the same number of genes. In addition, combining these two genes with three other genes to form a five-gene classifier outperforms existing classifiers with ten or more genes. With their exceptional predicting power, these two genes can be critical in fighting against the COVID-19 pandemic as a new focus and direction. Comparing the functional effects of these genes with a five-gene classifier with 100% accuracy identified and tested from blood samples in the literature, genes and their transcriptional response and functional effects to SARS-CoV-2 and genes and their functional signature patterns to COVID-19 antibody are significantly different, which can be interpreted as the former is the point of a phenomenon, and the latter is the essence of the disease. Such significant findings can help explore the causal and pathological clue between SARS-CoV-2 and COVID-19 disease and fight against the disease with more targeted vaccines, antiviral drugs, and therapies.

Omicron favors neuropilin1 binding over ACE2: Increased infectivity and available drugs

COVID-19 pandemic is continue with thousands of new cases every day around the world, even then different vaccines have been developed and proven efficacious against SARS-CoV-2. Several know antivirals drugs have been repurposed or tested against SARS-CoV-2 but we still don’t have an effective therapeutic strategy to control this viral infection. Moreover, in the race of finding out an efficient antiviral, excess uses of antiviral drugs developed a selective pressure on the virus that results in the high frequency of mutations and the possible emergence of antiviral drug resistance against SARS-CoV-2. Omicron is a recently emerged, highly mutated variant of SARS-CoV-2, reported for high infectivity. In the present study, we performed molecular docking analysis between available potential antiviral drugs (remdesivir, nirmatrelvir, molnupiravir, EIDD-1931, GS-441524, and favipiravir) and omicron S protein including S protein/ACE2 complex. Our results suggest high infectivity of omicron, however, the known antiviral drugs were found efficacious against omicron variant. Further, to investigate the high infectivity of omicron, we performed a docking experiment between omicron S protein and neuropilin1 (NRP1). Surprisingly, results suggest high affinities with NRP1 than ACE2. Overall, results suggest that omicron favors NRP1 binding over ACE2, the possible reason behind improved infectivity of omicron variant.

Hsp90 Inhibitors Inhibit the Entry of Herpes Simplex Virus 1 Into Neuron Cells by Regulating Cofilin-Mediated F-Actin Reorganization

Herpes simplex virus 1 (HSV-1) is a common neurotropic virus, the herpes simplex encephalitis (HSE) caused by which is considered to be the most common sporadic but fatal encephalitis. Traditional antiviral drugs against HSV-1 are limited to nucleoside analogs targeting viral factors. Inhibition of heat shock protein 90 (Hsp90) has potent anti-HSV-1 activities via numerous mechanisms, but the effects of Hsp90 inhibitors on HSV-1 infection in neuronal cells, especially in the phase of virus entry, are still unknown. In this study, we aimed to investigate the effects of the Hsp90 inhibitors on HSV-1 infection of neuronal cells. Interestingly, we found that Hsp90 inhibitors promoted viral adsorption but inhibited subsequent penetration in neuronal cell lines and primary neurons, which jointly confers the antiviral activity of the Hsp90 inhibitors. Mechanically, Hsp90 inhibitors mainly impaired the interaction between Hsp90 and cofilin, resulting in reduced cofilin membrane distribution, which led to F-actin polymerization to promote viral attachment. However, excessive polymerization of F-actin inhibited subsequent viral penetration. Consequently, unidirectional F-actin polymerization limits the entry of HSV-1 virions into neuron cells. Our research extended the molecular mechanism of Hsp90 in HSV-1 infection in neuron cells and provided a theoretical basis for developing antiviral drugs targeting Hsp90.

Disorders of the Cholinergic System in COVID-19 Era—A Review of the Latest Research

The appearance of the SARS-CoV-2 virus initiated many studies on the effects of the virus on the human body. So far, its negative influence on the functioning of many morphological and physiological units, including the nervous system, has been demonstrated. Consequently, research has been conducted on the changes that SARS-CoV-2 may cause in the cholinergic system. The aim of this study is to review the latest research from the years 2020/2021 regarding disorders in the cholinergic system caused by the SARS-CoV-2 virus. As a result of the research, it was found that the presence of the COVID-19 virus disrupts the activity of the cholinergic system, for example, causing the development of myasthenia gravis or a change in acetylcholine activity. The SARS-CoV-2 spike protein has a sequence similar to neurotoxins, capable of binding nicotinic acetylcholine receptors (nAChR). This may be proof that SARS-CoV-2 can bind nAChR. Nicotine and caffeine have similar structures to antiviral drugs, capable of binding angiotensin-converting enzyme 2 (ACE 2) epitopes that are recognized by SARS-CoV-2, with the potential to inhibit the formation of the ACE 2/SARS-CoV-2 complex. The blocking is enhanced when nicotine and caffeine are used together with antiviral drugs. This is proof that nAChR agonists can be used along with antiviral drugs in COVID-19 therapy. As a result, it is possible to develop COVID-19 therapies that use these compounds to reduce cytokine production. Another promising therapy is non-invasive stimulation of the vagus nerve, which soothes the body’s cytokine storm. Research on the influence of COVID-19 on the cholinergic system is an area that should continue to be developed as there is a need for further research. It can be firmly stated that COVID-19 causes a dysregulation of the cholinergic system, which leads to a need for further research, because there are many promising therapies that will prevent the SARS-CoV-2 virus from binding to the nicotinic receptor. There is a need for further research, both in vitro and in vivo. It should be noted that in the functioning of the cholinergic system and its connection with the activity of the COVID-19 virus, there might be many promising dependencies and solutions.

In Vitro Efficacy of Cyclosporine A and Various Antiseptics and Antiviral Drugs on Adenovirus Genotype 8, a Common Cause of Epidemic Keratoconjunctivitis

Purpose: To evaluate the in vitro efficacy of cidofovir, ganciclovir, povidone iodine, chlorhexidine, and cyclosporine A on adenovirus genotype 8 Methods: Conjunctival samples were collected from patients with adenoviral conjunctivitis and cultured in A549 cells. Adenovirus diagnosis was confirmed by RT-PCR. For each drug, the 50% cytotoxic concentration (CC₅₀) was determined. Subsequently, the antiviral activity was tested at concentrations below CC₅₀, and the 50% inhibitor concentration (IC₅₀) of drugs was determined.Results: While the IC₅₀ of cidofovir against adenovirus genotype 8 was 3.07 ± 0.8 µM, ganciclovir, povidone iodine, chlorhexidine, and cyclosporine A were not found to be effective against adenovirus genotype 8 at concentrations below the CC₅₀ value.Conclusions: Cidofovir was found effective and the IC₅₀ value was within the ranges in the literature. Ganciclovir and cyclosporine A were found to be ineffective at doses below the cytotoxic dose, povidone iodine and chlorhexidine were found to be highly cytotoxic.

Molecules Containing Cyclobutyl Fragments as Therapeutic Tools: A Review on Cyclobutyl Drugs

In recent years, cyclobutyl has become ever more influential in the field of drug design. Its unique four-membered ring structure is not only a useful intermediate for the synthesis of biomedical candidate materials, but also an indispensable framework for drug design and application. According to the therapeutic field, cyclobutyl drugs are roughly divided into tumor and cancer drugs, nervous system drugs, analgesics, antiviral drugs, and gastrointestinal drugs. Among them, platinum-based anticancer drugs containing cyclobutyl fragments have achieved remarkable success in the treatment of cancer, bringing new hope for the development of more cyclobutyl drugs. This article provides details of the research progress of the structure types, structure-activity relationships, targets, and mechanisms of cyclobutyl drugs that have been on the market or are in the clinical stage, and provides ideas for the discovery and synthesis of novel cyclobutyl-containing drugs.

Efficacy and safety of convalescent plasma therapy for severe COVID-19 patients：case series study and literature review

Background Coronavirus disease 2019 (COVID-19) is a new acute respiratory infectious disease which can lead to multiple organ dysfunction in severe patients. However, it is still a lack of effective antiviral drugs for COVID-19. Herein we investigated the efficacy and safety of convalescent plasma (CP) in the treatment of severe COVID-19, with an attempt to explore new therapeutic method. Methods Clinical data of three imported severe COVID-19 patients with CP treatment, who were under quarantine and treated in a designated COVID-19 hospital from March 2020 to April 2020, were collected and analyzed. Results The three patients were clinically classified as severe type, including one male and two females, aged 57, 59 and 65 years old, respectively. The main underling diseases included hypertension, diabetes, sequela of cerebral infarction and postoperative thyroid adenoma. The common symptoms included cough, fever and short of breath. All the patients received antiviral drugs and other supportive treatments. Additionally, CP treatment was also administrated for them. Forty-eight to seventy-two hours after CP transfusion, all the patients improved with alleviated symptoms, elevated arterial oxygen saturation, decreased C-reactive protein and interleukin-6 markers. And the total lymphocytes, T lymphocytes (CD3+) and their subsets (CD4+, CD8+) also obviously increased. Repeated chest CTs also showed obvious absorption of lesions in bilateral lung. Only one patient had mild allergic reaction during CP infusion, but no severe adverse reactions were found. Conclusions The early application of CP for severe COVID-19 patients can improve the condition rapidly, and the therapy is generally effective and safe.