Antiviral Chemistry and Chemotherapy最新文献

Severe acute respiratory syndrome coronavirus 2 is an RNA virus currently causing a pandemic. Due to errors during replication, mutations can occur and result in cell adaptation by the virus or in the rise of new variants. This can change the attachment receptors' usage, result in different morphology of plaques, and can affect as well antiviral development. Indeed, a molecule can be active on laboratory strains but not necessarily on circulating strains or be effective only against some viral variants. Experiments with clinical samples with limited cell adaptation should be performed to confirm the efficiency of drugs of interest. In this protocol, we present a method to culture severe acute respiratory syndrome coronavirus 2 from nasopharyngeal swabs, obtain a high viral titer while limiting cell adaptation, and assess antiviral efficiency.

Seasonal flu is caused by influenza infection, a virus that spreads easily in human population with periodical epidemic outbreaks. The high mutational rate of influenza viruses leads to the emergence of strains resistant to the current treatments. Due to that, scientific research is focusing on the development of new anti-influenza agents as alternative or complementary treatments. Olive tree (Olea europaea L.) has been a source of ancestral remedies due to its antimicrobial activity. Thus, the aim of this study was to test the anti-influenza activity of a standardized olive leaf extract rich in elenolic acid (EA), Isenolic^®, compared with oseltamivir. Isenolic^® extract was characterized by High Performance Liquid Chromatography (HPLC)-Mass Spectrometry and its content in EA was determined by HPLC. Cytotoxicity, viral neuraminidase inhibitor activity and cell viability protection against influenza infection of Isenolic^® were tested in vitro using sialic acid overexpressing Madin-Darby Canine Kidney cells. Isenolic^® formulations showed a 4% and 8% dry basis. Oseltamivir and Isenolic^® extracts showed anti-influenza activity. The 8% Isenolic^® formulation showed a dose-dependent neuraminidase inhibitor activity higher than the 4% formulation, and preserved cell viability under viral infection. Thus, Isenolic^® become a promising natural alternative to existing influenza treatments.

Human norovirus is the main cause of viral gastroenteritis, resulting annually in ∼ 700 million infections and 200,000 deaths, of whom most are children <5 years. Mouse norovirus-infected macrophages are the most widely used in vitro system to screen and characterize the antiviral effect of norovirus-targeting small molecules. We have previously established antiviral assays using this system, identified novel inhibitors and performed additional studies in order to have a first insight into their mechanism of action. After the identification of novel small molecules with anti-norovirus activity (part 1 of this protocol), we here describe the logical next step which entails the generation of early information of their mode of action. This information together with a continuous improvement of the potency of compounds will contribute to the optimization of a compound class towards in vivo efficacy and a successful preclinical development.

Dysfunction of CD4⁺ T cells by HIV infection can cause serious immune defects. Recently, Campbell and colleagues described an intriguing and simple therapeutic method for HIV-infected resting central memory CD4⁺ T cells (HIV-T_CM), dependently on inhibitor of apoptosis (IAP) family proteins-targeted and second mitochondria-derived activator of caspases (SMAC) mimetics-mediated apoptosis, which is only triggered in HIV-T_CM and not uninfected ones. Autophagy induction and subsequent formation of a ripoptosome-like death signaling complex were observed after such treatment, which may partially explain the potential mechanism. However, the direct intracellular inhibitory effects of IAPs on autophagy, as well as the critical roles of autophagy in activating extracellular anti-infection immune responses, warrant further investigation. Thus, this pointer aims to provide potential alternative mechanisms and to suggest important avenues for follow-up study.

Human norovirus is the main cause of viral gastroenteritis, resulting annually in ∼ 700 million infections and 200,000 deaths, of whom most are children <5 years. Mouse norovirus-infected macrophages are the most widely used in vitro system to screen and characterize the antiviral effect of norovirus-targeting small molecules. We have previously established antiviral assays using this system, identified novel inhibitors and performed additional studies in order to have a first insight into their mechanism of action. As potent and safe anti-norovirus small molecules are urgently needed, we here describe the detailed protocol for a set of assays that will allow the identification of novel norovirus inhibitors.

Many species of the order Bunyavirales contain potentially fatal viruses that lack effective medical countermeasures and are therefore collectively a major public health threat. Here, we describe a cell-based assay using Bunyamwera virus (BUNV)-mCherry to identify and characterize new antiviral molecules against bunyaviruses. BUNV is the type species for the genus Orthobunyavirus and has been reported to cause mild symptoms in humans, such as fever, joint pain, and rash. One major benefit of using our fluorescence-based assay over classical CPE-based assays is the fact that the antiviral effect of the tested compounds and their effect on the cell viability can be determined within the same assay well. For that reason, this type of assay could significantly advance our preclinical efforts towards finding new antiviral molecules against bunyaviruses.

Background: Drug repurposing is a cost-effective strategy to identify drugs with novel effects. We searched for drugs exhibiting inhibitory activity to Herpes Simplex virus 1 (HSV-1). Our strategy utilized gene expression data generated from HSV-1-infected cell cultures which was paired with drug effects on gene expression. Gene expression data from HSV-1 infected and uninfected neurons were analyzed using BaseSpace Correlation Engine (Illumina®). Based on the general Signature Reversing Principle (SRP), we hypothesized that the effects of candidate antiviral drugs on gene expression would be diametrically opposite (negatively correlated) to those effects induced by HSV-1 infection.

Results: We initially identified compounds capable of inducing changes in gene expression opposite to those which were consequent to HSV-1 infection. The most promising negatively correlated drugs (Valproic acid, Vorinostat) did not significantly inhibit HSV-1 infection further in African green monkey kidney epithelial cells (Vero cells). Next, we tested Sulforaphane and Menadione which showed effects similar to those caused by viral infections (positively correlated). Intriguingly, Sulforaphane caused a modest but significant inhibition of HSV-1 infection in Vero cells (IC50 = 180.4 µM, p = 0.008), but exhibited toxicity when further explored in human neuronal progenitor cells (NPCs) derived from induced pluripotent stem cells.

Conclusions: These results reveal the limits of the commonly used SRP strategy when applied to the identification of novel antiviral drugs and highlight the necessity to refine the SRP strategy to increase its utility.

Macrolides are a large group of antibiotics characterised by the presence of a macro-lactone ring of variable size. The prototype of macrolide antibiotics, erythromycin was first produced by Streptomyces and associated species more than half a century ago; other related drugs were developed. These drugs have been shown to have several pharmacological properties: in addition to their antibiotic activity, they possess some anti-inflammatory properties and have been also considered against non-bacterial infections. In this review, we analysed the available clinical evidences regarding the potential anti-viral activity of macrolides, by focusing on erythromycin, clarithromycin and azithromycin. Overall, there is no significant evidences so far that macrolides might have a direct benefit on most of viral infections considered in this review (RSV, Influenza, coronaviruses, Ebola and Zika viruses). However, their clinical benefit cannot be ruled out without further and focused clinical studies. Macrolides may improve the clinical course of viral respiratory infections somehow, at least through indirect mechanisms relying on some and variable anti-inflammatory and/or immunomodulatory effects, in addition to their well-known antibacterial activity.

Background: Recently, new direct-acting antivirals (DAAs) are known to eradicate chronic hepatitis C (CHC) virus infection and prevent the progression of liver fibrosis. Liver fibrosis may predispose to liver cirrhosis or hepatocellular carcinoma. We investigated the effect of DAAs on liver fibrosis using non-invasive methods, and evaluated the correlations of these methods.

Methods: We retrospectively analyzed 68 patients with CHC who were treated with DAAs and reached sustained virologic response at 12 weeks post-treatment from January 2016 to October 2018. The degree of liver fibrosis was assessed using serum biomarkers, such as AST-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4) index. Liver stiffness was assessed using two-dimensional shear-wave elastography (2 D-SWE). The pre- and post-treatment serum biomarker levels and SWE findings were evaluated and compared.

Results: A total of 68 patients with CHC were enrolled. The median age was 58 years (52.3-73 years) and 37 patients (54.4%) were female. After treatment, the median APRI was decreased from 0.701 to 0.328 (P < 0.0001), and the median FIB-4 was decreased from 2.355 to 1.860 (P < 0.0001). The median kPa in 2 D-SWE significantly reduced from 6.85 to 5.66 (P = 0.013). APRI and FIB-4 were significantly correlated pre- and post-treatment; however, the correlation between the serum biomarkers and 2 D-SWE was partially significant.

Conclusion: The serum fibrosis biomarkers and liver stiffness on 2 D-SWE were shown to be improved after the treatment with DAAs. Further research including larger number of patients is needed to compare the efficacy of each evaluating method.