The central logic of the host-targeting approach rests on a fundamental constraint of virology. Viruses are genomic minimalists. They carry only a handful of their own proteins and rely extensively on host-cell factors for nearly every step of replication, from translation of viral messages to genome replication, packaging, and assembly. RNA viruses in particular, which include many of the most medically important pathogens such as influenza, SARS-CoV-2, Ebola, dengue, and enteroviruses, depend heavily on the host cell’s RNA-processing infrastructure. Host RNA-binding proteins, which normally regulate messenger RNA splicing, stability, localization, and translation, are among the most frequently co-opted factors. When a virus enters a cell, these proteins are recruited to viral RNA genomes and transcripts, where they perform functions essential to the invader.

This dependence creates what antiviral researchers call a genetic vulnerability. Because the virus cannot easily replace a missing host function with one of its own, a drug that blocks a critical host RNA-binding protein interaction can place the virus in an evolutionary bind. Resistance mutations that arise against direct-acting antivirals, which typically alter the viral target protein so the drug no longer binds, are far harder to evolve against host targets. The host protein remains unchanged, and any viral mutation that restores dependence on the blocked pathway would itself carry a fitness cost. The result, according to the review, is a higher barrier to drug resistance, one of the persistent weaknesses of conventional antiviral development.

The broad-spectrum potential of this strategy is equally significant. Traditional antivirals are narrow: a drug designed to inhibit the influenza neuraminidase does nothing against coronaviruses, and a protease inhibitor for hepatitis C has no effect on Ebola. This narrowness has repeatedly left clinicians without options when new pathogens emerge, as the early months of the COVID-19 pandemic made painfully clear. Host-targeted antivirals, by contrast, could in principle cover many viruses at once. If diverse RNA viruses all require, for example, host proteins involved in RNA cap formation, translation initiation, or RNA granule dynamics, then a single molecule that modulates that shared host pathway could suppress multiple unrelated infections. Such agents could be stockpiled in advance of outbreaks and deployed rapidly against known and unknown threats, a concept increasingly discussed under the umbrella of pandemic preparedness.

The technical challenge, the article acknowledges, is selectivity. Human RNA-binding proteins are not optional accessories; they are central to the biology of every cell. An inhibitor that shut down a host RNA-binding protein globally would be toxic. The most promising targets, therefore, are those for which viral dependence is unusually high or for which the host can tolerate partial inhibition. Some RNA-binding proteins, such as certain members of the heterogeneous nuclear ribonucleoprotein family and the La autoantigen, have known viral interaction surfaces that are structurally distinct from the regions used for normal cellular functions. Drugs that bind to these viral-specific interfaces, or that disrupt the protein-protein contacts between host factors and viral polymerases or nucleocapsids, could in theory block the virus while sparing the host pathway. Structure-based drug design, enabled by high-resolution cryo-electron microscopy and computational modeling, is making such precision interference increasingly feasible.

Recent advances in the RNA biology toolkit have accelerated the identification of candidate targets. Enhanced crosslinking and immunoprecipitation methods now allow researchers to map, at single-nucleotide resolution, which host proteins bind which viral RNAs inside infected cells. Proteomics approaches quantify how the composition of RNA-bound protein complexes shifts during infection. Together, these techniques have generated dense interaction maps that reveal which host RNA-binding contacts are recurrent across viral families and therefore represent the most broadly useful drug targets. The review synthesizes this growing literature to highlight proteins whose perturbation has been shown, in cell culture and in some cases animal models, to impair multiple viruses simultaneously while remaining tolerable to the host cell.

Several concrete examples illustrate the concept’s maturity. Host proteins involved in mRNA capping and methylation are recruited by viruses ranging from coronaviruses to flaviviruses, which either steal or mimic cap structures to ensure their RNAs are translated. Interfering with these host cofactors can block a step the virus cannot perform independently. Similarly, stress granule components and other RNA granule proteins have emerged as double-edged factors: viruses must either suppress or exploit granule formation, and pharmacological modulation of granule dynamics has been shown in multiple studies to restrict infection. RNA-binding proteins that regulate innate immune sensing, such as those controlling the accessibility of viral RNA to pattern-recognition receptors, offer another angle, since modulating them can amplify the cell’s own antiviral response rather than directly inhibiting the virus.

Translation of these findings into approved medicines remains a work in progress, and the review is candid about the obstacles. Host-targeted drugs must clear a higher toxicity bar than direct-acting antivirals, because their targets are present in healthy tissue. Delivery, dose scheduling, and patient selection all require careful optimization. Combination regimens, pairing a host-targeted agent with a traditional direct-acting antiviral, may offer the best of both worlds: the broad coverage and high resistance barrier of host targeting combined with the potency and safety profile of virus-specific inhibition. Such combinations could also be effective against chronic infections, where resistance development during long-term therapy is a persistent clinical problem. The authors point to the success of host-targeted drugs in other fields, including certain oncology therapies, as evidence that drugging host factors is a realistic goal when the biology is well understood.

The strategic case for investing in this area is framed against the backdrop of recurring epidemic threats. RNA viruses continue to spill over from animal reservoirs, and the review argues that a portfolio of broad-spectrum host-targeted antivirals would function as a form of pharmaceutical insurance, providing immediately deployable countermeasures during the critical window before pathogen-specific drugs and vaccines can be developed. The COVID-19 pandemic demonstrated both the speed with which a novel virus can circle the globe and the difficulty of repurposing narrow antivirals against it. Building a validated pipeline of host RNA-binding protein targets, supported by structural biology, chemical biology, and rigorous animal models, is presented as a research priority that could materially change the outcome of the next outbreak.

Subject of Research: Host RNA-binding proteins as broad-spectrum antiviral drug targets

Article Title: Host RNA-binding proteins as broad-spectrum targets for antiviral therapy

Article References: Biswas, S. (2026). Host RNA-binding proteins as broad-spectrum targets for antiviral therapy. npj Viruses. https://doi.org/10.1038/s44298-026-00234-0

Image Credits: AI Generated

DOI: 10.1038/s44298-026-00234-0

Keywords: antiviral therapy, RNA-binding proteins, host-directed antivirals, RNA viruses, broad-spectrum antivirals, drug resistance, virus-host interactions, pandemic preparedness, viral replication, innate immunity, SARS-CoV-2, influenza