Antiviral research最新文献

Monoclonal antibodies targeting the Spike protein of SARS-CoV-2 are effective against COVID-19 and might mitigate future pandemics. However, their efficacy is challenged by the emergence of antibody-resistant virus variants. We developed a method to efficiently identify such resistant mutants based on selection from mutagenized virus pools. By inducing mutations with the active compound of Molnupiravir, N4-hydroxycytidine (NHC), and subsequently passaging the virus in the presence of antibodies, we identified specific Spike mutations linked to resistance. Validation of these mutations was conducted using pseudotypes and immunofluorescence analysis. From a Wuhan-like strain of SARS-CoV-2, we identified the following mutations conferring strong resistance towards the corresponding antibodies: Bamlanivimab – E484K, F490S and S494P; Sotrovimab – E340K; Cilgavimab – K444R/E and N450D. From the Omicron B.1.1.529 variant, the strongly selected mutations were: Bebtelovimab – V445A; Sotrovimab – E340K and K356M; Cilgavimab – K444R, V445A and N450D. We also identified escape mutations in the Wuhan-like Spike for the broadly neutralizing antibodies S2K146 – combined G485S and Q493R – and S2H97 – D428G, K462E and S514F. Structural analysis revealed that the selected mutations occurred at antibody-binding residues within the receptor-binding domains of the Spike protein. Most of the selected mutants largely maintained ACE2 binding and infectivity. Notably, many of the identified resistance-conferring mutations are prevalent in real-world SARS-CoV-2 variants, but some of them (G485S, D428G, and K462E) have not yet been observed in circulating strains. Our approach offers a strategy for predicting the therapeutic efficacy of antibodies against emerging virus variants.

Flavivirus infections result in a variety of outcomes, from clinically inapparent infections to severe, sometimes fatal cases characterized by hemorrhagic manifestations and vascular leakage leading to shock (dengue), meningomyeloencephalitis (West Nile), and congenital abnormalities (Zika). Although there are approved vaccines against several flaviviruses, potentially enhancing cross-reactive immune responses have complicated the development and implementation of vaccines against dengue and Zika viruses, and no specific therapeutics currently exist. The flavivirus nonstructural protein 1 (NS1) is a promising antiviral target because it is a conserved multifunctional virulence factor that directly triggers vascular leak. We previously showed that interactions between NS1 and the ApoA1 lipoprotein modulate DENV infection. Here, we evaluated the potential of the ApoA1-mimetic peptide, 4F, to interfere with endothelial dysfunction mediated by the NS1 protein of dengue, Zika, and West Nile flaviviruses. In an in vitro model consisting of human endothelial cell monolayers, 4F inhibited NS1-induced hyperpermeability, as measured by a transendothelial electrical resistance assay, and prevented NS1-triggered disruption of the endothelial glycocalyx layer. We also demonstrate that treatment with 4F inhibited NS1 interaction with endothelial cells. Finally, we show that 4F protects against lethal DENV challenge in a mouse model, reducing morbidity and mortality in a dose-dependent manner. Our data demonstrate the potential of 4F to inhibit flavivirus NS1-mediated pathology and severe dengue disease in mice and suggest that 4F can also serve as a molecular tool to probe different NS1 functions in vitro and in vivo.

Objectives

CXC chemokine receptor 7 (CXCR7) plays pivotal roles in different virus infections. However, no research focused on the role of CXCR7 in hepatitis B virus (HBV)-infected patients. The primary aim of this study is to elucidate the role of CXCR7 in predicting the treatment response of chronic hepatitis B (CHB) patients undergoing pegylated interferon-alpha (PegIFNα) therapy.

Methods

Two cohorts with a total of 945 Chinese CHB patients (Cohort 1, n = 238; Cohort 2, n = 707) were enrolled in this retrospective study, all the patients were positive for hepatitis B e antigen (HBeAg) and received PegIFNα treatment for 48 weeks and followed-up for 24 weeks post-treatment. Nineteen tag single-nucleotide polymorphisms (SNPs) were selected within and surrounding the CXCR7 gene region. The associations of CXCR7 SNPs and polygenic score (PGS) with PegIFNα treatment response were investigated in the two cohorts.

Results

Among the 19 candidate SNPs of CXCR7, rs2952665 (A > G) was significantly associated with combined response (CR, defined as HBeAg seroconversion and HBV DNA level <3.3log₁₀IU/mL, P = 0.002) and hepatitis B surface antigen (HBsAg) decline (P = 0.015) in the two cohorts at week 72. Furthermore, a PGS comprising CXCR7_rs2952665 and five additional SNPs, which were previously recognized as biomarkers of PegIFNα treatment response, demonstrated a robust correlation with both CR (P = 1.38 × 10⁻¹²) and HBsAg decline (P = 0.003) in all the patients.

Conclusion

This research illustrated that CXCR7_rs2952665 is a promising predictor of the PegIFNα therapy efficiency in Chinese HBeAg-positive CHB patients. A PGS consisting of CXCR7_rs2952665 and five previously reported SNPs predicts treatment response to PegIFNα better.

Severe fever with thrombocytopenia syndrome virus (SFTSV), recently named as Dabie bandavirus, belongs to the family Phenuiviridae of the order Bunyavirales, is a newly-identified bunyavirus with a case fatality rate of up to 30%, posing a serious threat to public health. Lipid rafts on plasm membranes are important for the entry of enveloped viruses; however, the role of lipid rafts in bunyavirus entry remains unclear. In this study, we found that methyl-beta-cyclodextrin (MβCD), a drug that disrupts cholesterol in lipid rafts of cell membranes, inhibits SFTSV infection. Additionally, there is a back-complementary effect of SFTSV infection upon the addition of cholesterol. Moreover, the concentration of SFTSV particles in lipid rafts during entry directly indicated the role of lipid rafts as a gateway, whereas MβCD could inhibit SFTSV entry by affecting the structure of lipid rafts. In an in vivo study, MβCD also reduced the susceptibility of mice to SFTSV infection. Our results suggest that SFTSV can interact with Talin1 proteins on lipid rafts to enter host cells by endocytosis of lipid rafts and reveal the potential therapeutic value of MβCD for SFTSV infection.

Broad-spectrum antivirals can be extremely important for pandemic preparedness. Targeting host factors dispensable for the host but indispensable for the virus can result in high barrier to resistance and a large range of viruses targeted. PI4KB is a lipid kinase involved in the replication of several RNA viruses, but common inhibitors of this target are mainly active against members of the Picornaviridae family. Herein we describe the optimization of bithiazole PI4KB inhibitors as broad-spectrum antivirals (BSAs) active against different members of the Picornaviridae, Coronaviridae, Flaviviridae and Poxviridae families. Since some of these viruses are transmitted via respiratory route, the efficacy of one of the most promising compounds was evaluated in an airway model. The molecule showed complete viral inhibition and absence of toxicity. These results pave the road for the development of new BSAs.

While historically confined to endemic areas, Monkeypox virus (MPXV) infection has increasingly garnered international attention due to sporadic outbreaks in non-endemic countries in the last two decades and its potential for human-to-human transmission. In 2022, a multi-country outbreak of mpox disease was declared by the World Health Organization (WHO) and nearly 100 000 mpox cases have been reported since the beginning of this pandemic. The clade II variant of the virus appears to be responsible for the vast majority of these infections. While there are no antiviral drugs currently approved to treat mpox specifically, the use of tecovirimat (TPOXX®) and brincidofovir (Tembexa®) is recommended by the Centers for Disease Control and Prevention (CDC) for compassionate use in severe mpox cases, since both are FDA-approved for the treatment of the closely related smallpox disease. Given the emergence of multiple tecovirimat-resistant infections, we aimed to evaluate the treatment efficacy of brincidofovir and its active compound, cidofovir, against MPXV clade II strains. Following intranasal infection, we show that cidofovir and brincidofovir can strongly reduce the viral replication of MPXV clade IIa and IIb viruses in the respiratory tract of susceptible mice when administered systemically and orally, respectively. The high antiviral activity of both compounds against historical and currently circulating MPXV strains supports their therapeutic potential for clinical application.

Pyrazolo[3,4-d]pyrimidines represent one potent class of well tolerated and highly active rhinovirus (RV) inhibitors that act as capsid binders. The lead compound OBR-5-340 inhibits a broad-spectrum of RVs. Aiming to improve lead activity, we evaluated the impact of structural modifications in the 3-phenyl ring of OBR-5-340 on its potency and spectrum of anti-RV activity vitro. Our results demonstrate the crucial role of substitution at position 4 for strong, broad-spectrum anti-RV activity. The 4-methyl (RCB23137) and 4-chloro (RCB23138) derivatives outperformed OBR-5-340 in terms of potency and anti-RV activity spectrum. Based on these findings, the compounds were selected for computational binding studies. Molecular dynamic simulations with six RVs differing in OBR-5-340, RCB23137, and RCB23138 sensitivity proved the impact of dynamic features of two VP1 loops enveloping these inhibitors on antiviral potency.

The use of fixed dose-combinations of antivirals with different mechanisms of action has proven key in the successful treatment of infections with HIV and HCV. For the treatment of infections with SARS-CoV-2 and possible future epi-/pandemic coronaviruses, it will be important to explore the efficacy of combinations of different drugs, in particular to avoid resistance development, such as in patients with immunodeficiencies. This work explores the effect of a combination of 3 broad-spectrum antiviral nucleosides on the replication of coronaviruses. To that end, we made use of primary human airway epithelial cell (HAEC) cultures grown at the air-liquid interface that were infected with the beta coronavirus OC43. We found that the triple combination of GS-441524 (the parent nucleoside of remdesivir), molnupiravir and ribavirin resulted in a more pronounced antiviral efficacy than what could be expected from a purely additive antiviral effect. The potency of this triple combination was next tested in SARS-CoV-2 infected hamsters in a prophylactic setup. To that end, for each of the drugs, intentionally suboptimal or even ineffective doses were selected. Yet, in the lungs of all hamsters that received triple prophylactic therapy (but not in those that received the respective double combinations) no infectious virus was detectable. Our findings indicate that co-administration of approved drugs for the treatment of coronavirus infections should be further explored but also against other families of viruses with epidemic and pandemic potential for which no effective antiviral treatment is available.

Most coronavirus vaccines focus on the spike (S) antigen, but the frequent mutations in S raise concerns about the vaccine efficacy against new variants. Although additional antigens with conserved sequences are have been tested, the extent to which these vaccines can provide immunity against different coronavirus species remains unclear. In this study, we assessed the potential of nucleocapsid (N) as a coronavirus vaccine antigen. Immunization with MERS-CoV N induced robust immune responses, providing significant protection against MERS-CoV. Notably, MERS-CoV N elicited cross-reactive T cell responses to SARS-CoV-2 N and significantly reduced lung inflammation following a SARS-CoV-2 challenge in the transient hACE2 mouse model. However, in K18-hACE transgenic mice, the vaccine showed limited protection. Collectively, our findings suggest that coronavirus N can be an effective vaccine antigen against homologous viruses, but its efficacy may vary across different coronaviruses, highlighting the need for further research on pan-coronavirus vaccines using conserved antigens.

Given the worldwide risk for the outbreak of emerging/re-emerging respiratory viruses, establishment of new antiviral strategies is greatly demanded. In this study, we present a scheme to identify gapmer antisense oligonucleotides (ASOs) targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA that efficiently inhibit viral replication. We synthesized approximately 300 gapmer ASOs designed to target various SARS-CoV-2 RNA regions and evaluated their activity in cell-based assays. Through a multistep screening in cell culture systems, we identified that ASO#41, targeting the coding region for viral main protease, reduced SARS-CoV-2 RNA levels in infected cells and inhibited virus-induced cytopathic effects. Antiviral effect of ASO#41 was also observed in iPS cell-derived human lung organoids. ASO#41 depleted intracellular viral RNAs during genome replication in an endogenous RNaseH-dependent manner. ASO#41 showed a wide range of antiviral activity against SARS-CoV-2 variants of concern including Alpha, Delta, and Omicron. Intranasal administration to mice exhibited intracellular accumulation of ASO#41 in the lung and significantly reduced the viral infectious titer, with milder body weight loss due to SARS-CoV-2 infection. Further chemical modification with phosphoryl guanidine-containing backbone linkages provided an elevation of anti-SARS-CoV-2 activity, with 23.4 nM of 50% antiviral inhibitory concentration, one of the strongest anti-SARS-CoV-2 ASOs reported so far. Our study presents an approach to identify active ASOs against SARS-CoV-2, which is potentially useful for establishing an antiviral strategy by targeting genome RNA of respiratory viruses.