Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.01.24.633564

Combinations of approved oral nucleoside analogues confer potent suppression of alphaviruses in vitro and in vivo

Verwimp, S.·Wagoner, J.·Arenas, E. G.·De Coninck, L.·Abdelnabi, R.·Hyde, J. L.·Schiffer, J.·White, J. M. M.·Matthijnssens, J.·Neyts, J.·Polyak, S. J.·Delang, L.
View original source ↗Export metadata ↓

Abstract

BackgroundAlphaviruses, including chikungunya virus (CHIKV), pose a significant global health threat, yet specific antiviral therapies remain unavailable. MethodsWe evaluated combinations of three oral directly acting antiviral drugs (sofosbuvir (SOF), molnupiravir (MPV), and favipiravir (FAV)), which are approved for other indications, against CHIKV, Semliki Forest virus (SFV), Sindbis virus (SINV), and Venezuelan Equine Encephalitis virus (VEEV) in vitro and in vivo. We assessed antiviral efficacy in human skin fibroblasts and liver cells, as well as in a mouse model of CHIKV-induced arthritis. FindingsIn human skin fibroblasts, synergistic antiviral effects were observed for combinations of MPV + SOF and FAV + SOF against CHIKV, and for FAV + SOF against SFV. In human liver cells, FAV + MPV conferred additive to synergistic activity against VEEV and SINV, while SOF synergized with FAV against SINV. In mice, MPV improved CHIKV-induced foot swelling and reduced systemic infectious virus titres. Combination treatment with MPV and SOF significantly reduced swelling and infectious virus titres compared to monotherapies of each drug. Sequencing of CHIKV RNA from joint tissue revealed that MPV caused dose- dependent increases in mutations in the CHIKV genome. Upon combination therapy of MPV with SOF, the number of mutations was significantly lower compared to monotherapy with several higher doses of MPV. InterpretationCombining these approved oral nucleoside analogues confers potent suppression of multiple alphaviruses in vitro and in vivo with enhanced control of viral genetic evolution in face of antiviral pressure. These drug combinations may ultimately lead to the development of potent combinations of pan-family alphavirus inhibitors. FundingThis work was supported by a PhD fellowship granted to S.V. by the Research Foundation - Flanders (FWO) (11D5923N). L.D.C. was also supported by Research Foundation - Flanders (FWO) PhD fellowship (11L1325N). Dr. Polyak and Schiffer are partially supported by R01AI121129. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSAlphaviruses such as chikungunya virus (CHIKV), Sindbis virus (SINV), and Venezuelan Equine Encephalitis virus (VEEV) are a major threat for global health. Alphaviruses are responsible for debilitating diseases with major public health implications, yet no antiviral drugs are currently approved for treating these virus infections. Existing treatment options are limited to supportive care and are unlikely to provide protection against future outbreaks of other alphaviruses. Previous studies have shown that oral approved nucleoside analogues such as favipiravir (FAV), molnupiravir (MPV), and sofosbuvir (SOF) have antiviral activity against certain RNA viruses, including alphaviruses. However, systematic in vivo evaluations of these drugs and testing of drug combinations in both in vitro and in vivo settings are limited. Added value of this studyThis study provides a comprehensive evaluation of combinations of FAV, MPV and SOF against multiple alphaviruses in two human cell lines and a CHIKV mouse model. We demonstrate that certain combinations of these drugs confer synergistic antiviral activity, effectively suppressing CHIKV, SFV, SINV, and VEEV replication in vitro. Moreover, in vivo, we show for the first time that MPV treatment results in reduced CHIKV-induced foot swelling and systemic virus replication. Combining MPV with SOF enhances antiviral activity in mice as compared to monotherapy. By sequencing the viral genome, we show that MPV increases the number of mutations in a dose-dependent manner. Combination therapy of MPV and SOF reduces the number of mutations compared to higher doses of MPV. These findings highlight the potential of nucleoside analogue combinations as a promising therapeutic strategy against alphavirus infections. Implications of all the available evidenceThe results of this study suggest that combination therapy with approved nucleoside analogues could provide an effective treatment strategy for alphavirus infections. The observed increased efficacy of drug combinations supports the potential for dose optimization to enhance efficacy while reducing toxicity and development of resistance. Future research should focus on clinical evaluation of these drug combinations, pharmacokinetic studies, and further exploration of their impact on viral evolution. Given the expanding geographical distribution of alphaviruses and the lack of available treatments, these findings provide a foundation for developing pan-alphavirus antiviral therapies that could improve patient outcomes and global outbreak preparedness.

Source connections

Explore related subjects

microbiologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Verwimp, S., Wagoner, J., Arenas, E. G., De Coninck, L., Abdelnabi, R., Hyde, J. L., Schiffer, J., White, J. M. M., Matthijnssens, J., Neyts, J., Polyak, S. J., Delang, L.. 2025-01-25. Combinations of approved oral nucleoside analogues confer potent suppression of alphaviruses in vitro and in vivo. https://doi.org/10.1101/2025.01.24.633564

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

A population-scale landscape of the subgingival microbiome reveals divergent routes to periodontal dysbiosis

Periodontitis is an archetypical mucosal inflammatory disease in which microbiome dysbiosis at the tooth-epithelial interface interacts with host genetic and behavioral risk factors to drive immune-mediated tissue destruction. Although subgingival microbiome compositional shifts are thought to parallel disease severity, microbiome variation at the population-level and its relationship to periodontal clinical phenotypes and disease-modifying factors remain poorly defined. Here, we use unsupervised manifold learning to map the compositional landscape of the subgingival microbiome in 1,355 adults spanning periodontal health to severe periodontitis. We identified eight latent microbiome states organized along a branching continuum from eubiosis to dysbiosis. An intermediate microbial configuration marked ecological destabilization and bifurcation into two distinct periodontitis-associated dysbiotic trajectories, distinguished by links to gingival inflammation and smoking. Although the microbiome trajectories broadly tracked periodontal destruction, a minority of individuals showed discordant microbiome-clinical phenotypes, with some individuals with periodontitis retaining otherwise eubiotic microbiomes enriched for low-abundance pathobionts, while some cases of health or mild disease had highly dysbiotic communities, suggesting distinct host susceptibility. Together, these findings define a population-scale ecological landscape of the subgingival microbiome, reveal divergent trajectories to periodontal dysbiosis, and highlight heterogeneity in the relationship between microbial community structure and clinical disease expression.

microbiology↗
bioRxiv2026

The iron-binding siderophore enterobactin is required for the response of multi-drug resistant Klebsiella pneumoniae to zinc limitation

To persist during infection Klebsiella pneumoniae must overcome nutrient iron and zinc limitation imposed by the host immune system through a process called nutritional immunity. Secreted small molecule siderophores are a major virulence determinant of Klebsiella pneumoniae pathogenesis and are presumed to overcome nutritional immunity by binding iron for bacterial acquisition. In this work, we set out to identify how a multi-drug resistant K. pneumoniae grows in zinc limited environments. Using unbiased transcriptomics, proteomics, and an arrayed transposon screen, we identified that synthesis and uptake of the siderophore enterobactin is required to allow for growth in low zinc conditions. Iron-specific chelators did not replicate this phenotype and addition of supplemental iron through heme in growth media could not complement severe growth defects of enterobactin mutant K. pneumoniae experiencing zinc limitation. Finally, zinc starvation induced enterobactin production independent of the canonical zinc uptake regulator (Zur) transcription factor suggesting an unidentified regulatory mechanism by which Gram-negative pathogens may respond to zinc stress. Together, these studies expand the role of enterobactin beyond iron regulation and highlight a previously unreported link between iron and zinc homeostasis in Klebsiella pneumoniae.

microbiology↗
bioRxiv2026

A microbiota-derived protease links phage susceptibility to host epithelial responses

Bacteriophages are major ecological drivers of gut microbial ecology, yet whether bacterial mechanisms that determine phage susceptibility have consequences for the mammalian host remains poorly understood. Here, we identify dipeptidyl peptidase 11 (Dpp11a), the predominant active serine protease of the prevalent gut commensal Phocaeicola vulgatus, as an unexpected bacterial defence factor. Dpp11a protects against environmental proteases and confers resistance to bacteriophage infection. Metatranscriptomic analyses further reveal increased expression of both dpp11a and P. vulgatus-associated phage transcripts in ulcerative colitis stool samples, indicating that both components of this interaction are transcriptionally active in disease-associated human microbiomes. Using the microfluidic gut-on-a-chip co-culture model HuMiX, we show that the absence of Dpp11 is accompanied by altered epithelial tight-junction remodelling during phage-bacterial infection. Together, our findings reveal that the consequences of bacterial phage defence can extend beyond phage-bacterium interactions to the mammalian epithelium.

microbiology↗