The research team set out to determine whether dampening this kinase pathway could influence the course of infection with A/Puerto Rico/8/1934, the laboratory H1N1 strain universally abbreviated as PR8. Their experimental design was deliberately multi-layered. In cell culture, they infected susceptible cells with PR8 and treated them with GSK583 at defined concentrations, then quantified viral RNA and viral protein accumulation inside the cells. To measure the production of infectious progeny, they performed plaque-forming assays on culture supernatants, a classical virological technique in which diluted samples are overlaid onto fresh monolayers of cells and each infectious particle gives rise to a visible zone of cytopathic effect. In parallel, they moved to a mouse model of PR8 infection, treating animals early after inoculation and tracking body weight, disease severity, pulmonary viral load, and inflammatory markers over the course of the experiment.

The cellular results were consistent and pointed in a single direction. GSK583 reduced both the amount of viral RNA and the abundance of viral protein within infected cells, and supernatants collected from treated cultures contained significantly fewer plaque-forming units, indicating that the compound suppressed the release of infectious virions rather than merely distorting intracellular readouts. Importantly, the investigators used time-of-addition experiments to pinpoint where in the viral life cycle the drug exerted its effect. In this approach, the compound is added at different times relative to infection — before the virus is introduced, during the attachment phase, or only after adsorption has been completed. If a drug directly inactivates virions or blocks their binding to cell surface receptors, it must be present early to show activity. GSK583 failed to directly inactivate PR8 and did not measurably inhibit viral attachment under the conditions tested; instead, its antiviral effect became detectable only after the virus had adsorbed to cells. This pattern is characteristic of a compound that interferes with post-entry stages of replication or with host signaling pathways that the virus co-opts.

Having established antiviral activity in vitro, the team turned to the mouse model, where the stakes for host-directed therapy are higher because the immune system contributes both to viral clearance and to tissue damage. When GSK583 was administered early after infection, treated animals experienced alleviated disease severity compared with untreated controls. Quantitative assessment of lung tissue revealed reduced signals for the viral nucleoprotein — both its RNA transcripts and the antigen itself — indicating that viral replication in the respiratory tract was genuinely blunted, not simply redistributed. Alongside the reduction in viral load, the treated mice showed lower inflammatory readouts in the lung. This dual effect is notable because excessive inflammation is a hallmark of severe influenza, contributing to acute lung injury and, in the worst cases, acute respiratory distress syndrome, a syndrome that the authors explicitly reference in framing the clinical significance of their work.

The mechanistic core of the study concerns the RIPK2–MKK7–JNK signaling module. RIPK2 is a kinase with well-documented roles in innate immunity, particularly as an adaptor that transduces signals from NOD-like pattern recognition receptors, and the mitogen-activated protein kinase cascade it engages includes MKK7, a dual-specificity kinase that phosphorylates and activates JNK. JNK, in turn, is a stress-activated protein kinase whose phosphorylation status is a sensitive indicator of inflammatory and stress signaling intensity. Using protein interaction assays, the investigators demonstrated that the physical association between RIPK2 and MKK7 was linked to PR8 replication-related readouts under their experimental conditions, and that JNK phosphorylation tracked with viral replication. Genetic knockdown experiments and pharmacological inhibition corroborated the involvement of this axis, providing convergent lines of evidence rather than relying on a single technique.

Against this mechanistic backdrop, the effect of GSK583 became interpretable. Treatment with the compound was accompanied by a reduction in the RIPK2–MKK7 interaction and a corresponding decrease in JNK phosphorylation, findings consistent with the hypothesis that the drug works by loosening a signaling complex that influenza virus either requires or exploits. The authors are careful in their language here: they describe the data as consistent with a potential link between the signaling module and the observed antiviral effect, rather than claiming definitive causation. This restraint is scientifically appropriate, because RIPK2 has pleiotropic functions and inhibitor specificity is never absolute, a caveat the team acknowledges directly when they call for further studies to define the mechanistic specificity of the pathway in influenza infection.

Beyond the JNK arm, the study documented effects on a second major inflammatory pathway. GSK583 treatment reduced the phosphorylation of NF-κB p65, the canonical subunit of the transcription factor that drives expression of a large suite of pro-inflammatory genes, and it lowered the transcript levels of selected inflammatory cytokines in infected cells. The intersection of these two pathways is significant for influenza biology. The JNK and NF-κB cascades are both activated during influenza infection, both contribute to cytokine storm pathology, and both have been implicated in supporting various stages of the viral life cycle in prior literature. A single compound that dampens phosphorylation events in both cascades while simultaneously reducing viral replication therefore offers a pharmacologically attractive profile, at least in the models examined.

The translational implications deserve careful framing. GSK583 was developed in an industrial setting as a RIPK2 inhibitor, and its repurposing for influenza represents the kind of cross-indication thinking that host-directed antiviral research increasingly encourages. Because the target is a host protein, the theoretical barrier to viral escape is much higher than for virus-targeted drugs: the virus cannot simply mutate its own polymerase to render a host-directed compound obsolete. Moreover, a host-directed agent could in principle retain activity against multiple influenza subtypes and even against unrelated respiratory viruses that co-opt overlapping signaling networks. However, host-directed approaches carry their own risks, since interfering with innate immune signaling can impair genuine host defense, and the therapeutic window must be established empirically. The mouse data showing alleviated disease severity with early treatment are encouraging on this point, but early intervention windows are a known limitation of antiviral therapy in practice, because patients frequently present after peak viral replication has occurred.

The study’s methodological rigor is worth noting for readers assessing the strength of the conclusions. Cytotoxicity considerations were built into the design, with the abstract referencing the half-maximal cytotoxic concentration, the half-maximal inhibitory concentration, and the selectivity index — standard pharmacological metrics that distinguish genuine antiviral activity from nonspecific toxicity. Statistical analyses employed Student’s t-tests, analysis of variance, and log-rank tests as appropriate to the data structure, and all animal procedures were reviewed and approved by the Institutional Animal Care and Use Committee of Huazhong University of Science and Technology. The authors also flag that the paper was released as an accepted manuscript under accelerated sharing, subject to final editorial production, and they explicitly position their findings as proof-of-concept rather than as a validated therapeutic strategy.

What, then, does this work contribute to the field? It extends the map of host factors that influenza virus interacts with, placing RIPK2-associated signaling squarely within the network of pathways whose manipulation affects viral replication. It provides a concrete pharmacological tool — a compound with an existing development history — that the community can use to probe this pathway further. And it demonstrates, in both cellular and animal systems, that attenuating this signaling module can simultaneously reduce viral load and inflammatory output, addressing the two faces of influenza pathology in a single intervention. The open questions are equally clear: whether the RIPK2–MKK7 interaction is a direct requirement of the virus or an indirect consequence of altered cellular physiology, whether the effect generalizes beyond PR8 to circulating human strains and other subtypes, and whether the therapeutic window in mammals is wide enough to support clinical development. The authors’ call for further studies on mechanistic specificity and broader applicability is the appropriate next step, and the present findings supply a well-documented starting point for that work.

Subject of Research: Host-directed antiviral activity of the RIPK2 inhibitor GSK583 against A/PR/8 H1N1 influenza virus infection and associated inflammatory signaling

Article Title: GSK583 attenuates viral and inflammatory readouts in an A/PR/8 H1N1 infection model

Article References: Kuang, J., Zhou, J., Xiang, J., Ren, F., Fu, J.-J., Zhu, G., Li, Z., Ruan, H., Tan, X., Zhang, W., Zhou, M., Xu, J., Yang, Q., & Shang, Y. (2026). GSK583 attenuates viral and inflammatory readouts in an A/PR/8 H1N1 infection model. Virology Journal. https://doi.org/10.1186/s12985-026-03283-2

Image Credits: AI Generated

DOI: 10.1186/s12985-026-03283-2

Keywords: GSK583, RIPK2, influenza A virus, H1N1, JNK signaling, MKK7, NF-κB, host-directed antivirals, PR8 mouse model, inflammation, viral replication, antiviral therapy

Cowpea mild mottle virus, formally named Carlavirus vignae, is a betaflexivirus with a flexible filamentous particle and a single-stranded, positive-sense RNA genome. It infects soybean and other legume crops across tropical and subtropical regions, causing mosaic symptoms, leaf mottling and yield losses that make it a growing concern for soybean production. Like all positive-sense RNA viruses, it must co-opt host cell machinery to copy its genome, yet for betaflexiviruses the identity of the plant proteins involved in that process has remained largely a mystery. The new study, led by Larissa G. Zanardo, F. Murilo Zerbini and Claudine M. Carvalho of the Universidade Federal de Viçosa and collaborators at several Brazilian institutions, set out to close that gap by searching systematically for soybean proteins that contact the viral replication machinery.

The team’s starting point was the viral RNA-dependent RNA polymerase, the enzyme at the heart of genome replication. For many RNA viruses, the polymerase sits at the center of a multiprotein replication complex that also includes host factors, membranes and viral accessory proteins. Identifying which host proteins are pulled into this complex is therefore a critical step toward understanding, and potentially disrupting, the infection cycle. To find such partners, the researchers constructed a soybean complementary DNA library and screened it against the CPMMV polymerase domain using a yeast two-hybrid assay, a technique in which two candidate proteins are fused to separate halves of a transcription factor; if the proteins interact, the reassembled factor switches on reporter genes that make the yeast colonies change color.

Controls were carefully built into the screen. The viral polymerase domain fused to the yeast DNA-binding domain proved neither toxic to the yeast cells nor capable of switching on reporters on its own, ruling out false positives from self-activation. When the full soybean library was interrogated, one clone that repeatedly came through the screen encoded GmASMT8, a member of the N-acetylserotonin O-methyltransferase family. These enzymes are best known in plants for catalyzing steps in the melatonin biosynthesis pathway, converting N-acetylserotonin into melatonin, a molecule implicated in stress responses and development. A role for such an enzyme in viral replication had not previously been described for this virus family.

To confirm that the interaction was genuine rather than an artifact of the yeast system, the researchers turned to bimolecular fluorescence complementation. In this approach, the two candidate proteins are each fused to one nonfluorescent half of a fluorescent protein and expressed together in plant cells; fluorescence is restored only if the proteins come into close proximity. The assay again supported a physical association between the CPMMV polymerase domain and GmASMT8, providing independent evidence in a plant cellular environment that the two proteins meet during infection.

Subcellular localization studies then revealed where these encounters take place. GmASMT8 was found distributed in the cytoplasm, the expected location for a soluble metabolic enzyme. The viral polymerase domain, by contrast, formed punctate structures associated with the endoplasmic reticulum, a pattern consistent with the membrane-associated replication sites that many positive-sense RNA viruses build on ER membranes. The cytoplasmic distribution of GmASMT8 overlaps with these ER-associated viral structures, making the cytoplasm the plausible arena in which the host enzyme and the viral polymerase interact to support genome replication.

Correlation alone does not establish function, so the team next asked whether GmASMT8 actually matters for viral multiplication. Gene expression analysis showed that GmASMT8 transcript levels rise during CPMMV infection, indicating that the plant’s own program responds to the virus by producing more of the enzyme. The researchers then manipulated the gene in both directions. When GmASMT8 was overexpressed in soybean protoplasts, single plant cells stripped of their walls that are a standard platform for testing viral replication, CPMMV accumulated to higher levels than in control cells. Conversely, when GmASMT8 expression was knocked down in whole soybean plants using virus-induced gene silencing, a technique that harnesses an unrelated viral vector, in this case bean pod mottle virus, to trigger the plant’s RNA interference machinery against a target gene, viral accumulation dropped markedly.

The silencing experiments were validated with appropriate controls. A construct targeting the phytoene desaturase gene produced the characteristic photobleached phenotype, confirming that the vector system efficiently silenced soybean genes, and quantitative measurements confirmed that GmASMT8 transcripts were reduced in plants receiving the GmASMT8 silencing construct over multiple time points. Statistical comparisons across treatments supported the conclusion that reduced GmASMT8 levels translate into reduced viral loads. Taken together, the gain-of-function and loss-of-function results position GmASMT8 as a positive regulator of CPMMV accumulation, meaning the virus benefits from the presence of this host enzyme throughout its infection cycle.

The broader significance of the work lies in what it reveals about a poorly charted corner of plant virology. Betaflexiviridae includes economically important genera such as Carlavirus, Potexvirus, Trichovirus and Foveavirus, whose members infect crops ranging from potatoes and grapes to fruit trees and ornamentals. Despite this agricultural importance, the host factors that support betaflexivirus replication have remained largely unknown, in contrast to the extensive host-factor catalogs available for viruses such as potyviruses or tombusviruses. By identifying GmASMT8 as a partner of the CPMMV polymerase domain, the Brazilian team has delivered the first report of a host protein interacting with the replication enzyme of any Betaflexiviridae member, establishing a foundation for comparative studies across the family.

The study also raises intriguing questions about why a melatonin-biosynthetic enzyme would serve a virus. One possibility is that GmASMT8 contributes a biochemical activity that directly assists RNA synthesis or the assembly of replication complexes. Another is that the virus manipulates the enzyme’s normal role in stress hormone metabolism, perhaps dampening antiviral responses that depend on melatonin or related signaling molecules. Distinguishing between these mechanisms will require further experiments, but the practical implications are already apparent. Host factors that viruses depend on are attractive targets for resistance breeding and genome editing, because disrupting a host protein that a virus needs can confer broad and durable resistance while imposing minimal cost on the plant. If GmASMT8 proves dispensable for normal soybean growth under field conditions, reducing its availability to the virus, or blocking the protein-protein interaction with the viral polymerase, could become a strategy for protecting soybean crops against cowpea mild mottle virus. For now, the study stands as a reminder that even well-studied cellular enzymes can harbor hidden roles in the arms race between plants and their pathogens.

Subject of Research: Host factor GmASMT8 in the replication of the betaflexivirus Carlavirus vignae in soybean

Article Title: The betaflexivirus Carlavirus vignae recruits N-acetylserotonin O-methyltransferase 8 (GmASMT8) during its replication in soybean

Article References: Zanardo, L. G., Barbosa, T. M. C., Alves, M. S., Queiroz, S. S., Bruckner, F. P., Silva, F. N., Zerbini, F. M., & Carvalho, C. M. (2026). The betaflexivirus Carlavirus vignae recruits N-acetylserotonin O-methyltransferase 8 (GmASMT8) during its replication in soybean. Virology Journal. https://doi.org/10.1186/s12985-026-03293-0

Image Credits: AI Generated

DOI: 10.1186/s12985-026-03293-0

Keywords: CPMMV, GmASMT8, Betaflexiviridae, Carlavirus, soybean, RNA-dependent RNA polymerase, viral replication, host-virus interaction, yeast two-hybrid, virus-induced gene silencing, plant virology, melatonin biosynthesis

The team, led by Jinping Dou and Shuang Wei, who contributed equally to the work, with corresponding authors Xingjian Liu and Yinü Li, worked from GETV-BJ0304, an attenuated strain previously isolated by the group. Attenuated strains are attractive backbones for reverse genetics systems because they can be manipulated under less stringent containment considerations while still recapitulating core features of alphavirus biology. Using a seamless cloning method, the researchers assembled the complete viral genome rapidly, avoiding the restriction-site scars and extraneous sequences that plague older ligation-based approaches. Seamless assembly matters in this context because alphavirus genomes are compact and densely packed; even small insertions of nonviral sequence at junction sites can alter replication kinetics and confound downstream experiments.

Getah virus belongs to the Alphavirus genus within the Togaviridae family, a group characterized by a positive-sense, single-stranded RNA genome of roughly 11 to 12 kilobases. The genome is organized into two open reading frames: the nonstructural polyprotein encoded at the 5′ end, which supplies the replication machinery, and the structural polyprotein at the 3′ end, which is translated from a subgenomic RNA. This subgenomic RNA is produced from an internal promoter, conventionally called the 26S subgenomic promoter (26SGP), which drives very high levels of structural protein expression during infection. That architecture creates two natural insertion points for a reporter gene, and each comes with distinct trade-offs that the Beijing team set out to quantify.

The first strategy exploits the 2A self-cleaving peptide, a short sequence, originally described in picornaviruses, that induces ribosomal skipping during translation. When a reporter gene such as enhanced green fluorescent protein (EGFP) is fused to a viral polyprotein through a 2A sequence, the translating ribosome ‘skips’ a peptide bond at the 2A motif, releasing the reporter as a largely separate protein while leaving the viral polyprotein essentially intact. The elegance of this approach is that the reporter is expressed from the same mRNA as the viral protein, so reporter output tracks faithfully with viral gene expression, and the viral genome length increases only modestly. The second strategy inserts an additional copy of the 26S subgenomic promoter upstream of the reporter gene, creating a second subgenomic RNA dedicated to reporter translation. This duplicated-promoter design can drive very high reporter expression, but it adds substantial sequence to the genome and introduces an extra promoter element that the viral replication machinery must recognize and that recombination can act upon.

Which strategy wins has often been assumed rather than tested, particularly for attenuated alphavirus backbones where genomic flexibility may differ from that of virulent laboratory strains. The researchers constructed reporter viruses carrying EGFP through both routes and then subjected the resulting recombinants to a battery of characterization assays. The results were decisive: for the GETV-BJ0304 backbone, the 2A self-cleaving peptide strategy proved highly efficient and stable. The recombinant virus, designated GETV-2A/EGFP, displayed high infection efficiency and, importantly, maintained its reporter over serial passages, a property that many reporter alphaviruses lose as deletion or mutation of the foreign sequence confers a replicative advantage.

Genetic stability is the quiet battleground of reporter virology. A reporter virus that sheds its fluorescent cargo after a few rounds of replication is worse than useless, because it silently biases experiments: the cells that remain fluorescent are those infected by the fittest, reporter-retaining variants, which may not represent the population the researcher intends to study. By demonstrating that GETV-2A/EGFP retains high-level EGFP expression through extended passaging, the study provides a technical platform whose fluorescence can be taken as a reliable proxy for infection. That reliability underpins quantitative applications ranging from neutralization assays and antiviral screening to single-cell analyses of viral spread, where fluorescence intensity and infected-cell counts feed directly into the analysis.

The comparison also carries broader lessons for alphavirus reverse genetics. The 26S promoter duplication strategy, while capable of strong expression, imposes a larger genomic burden and creates duplicated promoter sequences that are intrinsically recombination-prone. In an attenuated backbone, where replication fidelity and genomic tolerance may already be strained, that burden appears to be decisive. The 2A approach, by contrast, keeps the added sequence short and avoids duplicating regulatory elements, aligning reporter expression with the natural translational output of the viral polyprotein. The finding does not necessarily generalize to every alphavirus or every backbone, but it offers an evidence-based default for researchers constructing reporter clones in attenuated strains, replacing intuition with head-to-head data.

Why does Getah virus warrant this level of technical investment? The virus circulates in a transmission cycle involving mosquitoes and vertebrate hosts, and it has caused notable epizootics in horses, characterized by fever, edema, and urticarial rash, as well as reproductive disease and neurological signs in piglets. Although GETV is not currently a major human pathogen, its recent outbreaks and demonstrated potential for increased virulence have placed it alongside other arboviruses as a public-safety concern. Climate change, expanding mosquito vector ranges, and intensification of livestock production all create conditions favorable to emergence. A robust reverse genetics system is the prerequisite for dissecting which viral proteins and RNA elements drive host range, virulence, and transmission, and for rationally designing attenuated vaccine candidates or antiviral targets rather than discovering them by trial and error.

The platform described in the study enables exactly that dissection. With a stable fluorescent reporter embedded in an otherwise authentic viral genome, researchers can monitor replication in real time, quantify infection in the presence of interfering RNAs or candidate drugs, and screen host genes for factors that restrict or support GETV invasion. The authors frame the system as a crucial technical platform for in-depth analysis of GETV replication and pathogenic mechanisms, as well as for exploring new strategies that help the host resist viral invasion. In practical terms, that means the clone can serve as the starting point for mutant libraries, for structure-function studies of the nonstructural proteins, and for testing how specific mutations alter tropism in mosquito and mammalian cells.

The work, funded by China’s National Key Research and Development Program, the National Natural Sciences Foundation of China, the Agricultural Science and Technology Innovation Program, and the Central Public-interest Scientific Institution Basal Research Fund, arrives as an open-access publication, making the construction logic and characterization data available to laboratories worldwide. As arboviruses continue to test the boundaries of veterinary and public health preparedness, tools of this kind, a rapidly assembled infectious clone paired with a validated, stable reporter strategy, convert an emerging pathogen from an opaque threat into an experimentally tractable one. For Getah virus, the 2A-based design now stands as the benchmark against which future reporter constructs will be measured.

Subject of Research: Construction and comparison of reporter gene insertion strategies in Getah virus reverse genetics systems

Article Title: Comparison and characterization of construction strategies for Getah virus infectious clones with stable, high-level expression of reporter gene

Article References: Dou, J., Wei, S., Gao, X., Wu, T., Zhao, Z., Zhang, Z., Liu, X., & Li, Y. (2026). Comparison and characterization of construction strategies for Getah virus infectious clones with stable, high-level expression of reporter gene. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06457-x

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06457-x

Keywords: Getah virus, alphavirus, reverse genetics, infectious clone, reporter gene, EGFP, 2A self-cleaving peptide, subgenomic promoter, arbovirus, genetic stability, viral replication, veterinary virology

Long noncoding RNAs, typically defined as transcripts longer than two hundred nucleotides that are not translated into proteins, were once dismissed by many researchers as transcriptional noise. Early genome sequencing projects revealed that while only a small fraction of the human genome encodes proteins, the vast majority of it is transcribed into RNA. Skeptics argued that most of these transcripts were accidental byproducts of a cellular machinery that transcribes promiscuously. Over the past two decades, however, careful functional studies have dismantled that view. Individual long noncoding RNAs have been shown to sculpt chromatin, modulate the stability and translation of messenger RNAs, serve as scaffolds for multi-protein complexes, and act as molecular decoys that sequester transcription factors or microRNAs. Their regulatory reach extends across nearly every layer of gene expression, and their expression patterns are often exquisitely specific to particular cell types, developmental stages, and physiological conditions, including infection.

What makes the cross-kingdom framing particularly compelling is that long noncoding RNAs are not a peculiarity of animals. Plants produce them in abundance, and plant pathologists have documented RNA molecules that move from fungal pathogens into plant cells and vice versa. Small RNAs were the first cross-kingdom RNA travelers to be described in detail, with fungal pathogens such as Botrytis cinerea shown to deliver small RNAs into plant cells where they hijack the host’s own RNA interference machinery to suppress immune genes. Long noncoding RNAs now appear to participate in comparable exchanges, functioning both as sources of regulatory small RNAs and as independent effectors in their own right. In agricultural contexts, this discovery has opened an entirely new frontier: if pathogen RNAs silence crop immune genes, then engineered host RNAs might be deployed to silence essential pathogen genes, a strategy sometimes described as host-induced gene silencing.

In mammalian systems, the interplay between long noncoding RNAs and pathogens is equally rich. Upon infection, host cells reprogram their long noncoding RNA landscape on a massive scale. Interferon signaling, the centerpiece of antiviral immunity, induces a constellation of noncoding transcripts whose functions are only beginning to be mapped. Some of these RNAs amplify antiviral responses, acting as positive regulators that stabilize interferon-stimulated messenger RNAs or promote the signaling cascades triggered by pattern-recognition receptors. Others do the opposite, serving as brakes on inflammation that prevent immune damage to host tissues. Pathogens, in turn, have learned to manipulate this layer of regulation. Viruses encode their own noncoding RNAs and also reshape the abundance of host long noncoding RNAs, co-opting regulatory molecules to create a cellular environment favorable to viral replication, persistence, and escape from immune surveillance.

Bacterial pathogens add yet another dimension to the dialogue. Although bacteria do not possess the same RNA processing machinery as eukaryotes, they are masters of RNA regulation, using small RNAs and structured RNA elements to fine-tune gene expression in response to environmental cues. Emerging work suggests that bacterial RNAs can be released into host cells, whether through outer membrane vesicles, secretion systems, or the controlled lysis of bacterial cells, and that these molecules can modulate host signaling pathways. Conversely, host long noncoding RNAs influence the outcome of bacterial infection by regulating the expression of genes involved in innate immunity, inflammasome activation, autophagy, and cell death. Each of these pathways is a battleground, and RNA regulation sits at the heart of the fight.

The mechanistic versatility of long noncoding RNAs helps explain why they are such effective mediators of this dialogue. Unlike proteins, which must be synthesized, folded, and often trafficked through elaborate pathways, RNAs can be produced rapidly and can act through base-pairing interactions that are comparatively simple to predict and, at least in principle, to engineer. A single long noncoding RNA can interact with DNA, other RNAs, and proteins simultaneously, functioning as a hub that integrates multiple regulatory inputs. This multifunctionality means that a pathogen that targets one host long noncoding RNA can, in a single move, perturb an entire regulatory network. It also means that experimental perturbation of these RNAs, through antisense oligonucleotides, small interfering RNAs, or CRISPR-based approaches, can reveal network-level effects that single-gene knockout studies of proteins might miss.

Technological advances have driven much of the recent progress. Long-read sequencing technologies now allow full-length characterization of transcript isoforms, revealing complexity that short-read approaches obscured. Strand-specific and single-cell RNA sequencing methods have made it possible to profile the noncoding transcriptome of individual infected cells, exposing the heterogeneity of host responses within a tissue. Cross-kingdom RNA detection has benefited from computational pipelines designed to distinguish pathogen-derived reads from host transcripts, a nontrivial challenge given the low abundance of microbial RNAs within a sea of host RNA. Functional validation remains the rate-limiting step: assigning a concrete mechanism to a differentially expressed long noncoding RNA requires loss-of-function and gain-of-function experiments, mapping of interaction partners, and careful demonstration that observed effects are not artifacts of off-target perturbation. The field has matured considerably in its rigor, and the commentary in Cell Research reflects that maturation, emphasizing that the most convincing examples of cross-kingdom RNA communication are those in which the transferred RNA is detected in the recipient, its target is identified, and a functional consequence is demonstrated.

The translational implications are substantial. Host long noncoding RNAs that promote antiviral or antibacterial defense could serve as biomarkers that distinguish active infection from convalescence, or as predictors of disease severity. Therapeutically, RNA-based drugs have finally come of age: antisense oligonucleotides and small interfering RNA therapeutics have been approved for a range of conditions, and the mRNA vaccine success of the COVID-19 pandemic demonstrated that RNA delivery technologies can be scaled to global public health needs. Applying these tools to infection biology, whether by enhancing protective host noncoding RNAs or by directly silencing pathogen transcripts, is a logical next step. In agriculture, RNA-based crop protection strategies are already moving from the laboratory to the field, and a deeper understanding of cross-kingdom RNA exchange will inform both the design of such products and the assessment of their ecological effects on the wider microbiome.

Significant questions remain open. The mechanisms by which RNAs cross cellular boundaries, survive extracellular environments, and enter recipient cells are still incompletely understood, and the physiological relevance of some reported transfers continues to be debated. Dosage is a critical issue: RNA communication depends on molecules reaching functional concentrations in recipient cells, and measuring that accurately in vivo is technically demanding. Specificity is another challenge, since long noncoding RNAs often act at low levels through partial complementarity, raising the risk of unintended interactions when RNAs are manipulated therapeutically. Nonetheless, the conceptual shift is clear and consequential. Host and pathogen are no longer best understood as two organisms exchanging only molecular blows at the protein level; they are two transcriptomes in conversation, each reading and misreading the other’s RNA messages. The commentary’s central message, that long noncoding RNAs broaden the host–pathogen dialogue across kingdoms, captures a field in the midst of redefining itself, and it points toward a future in which the language of RNA becomes as central to infection biology as the language of proteins has always been.

Subject of Research: The role of long noncoding RNAs in cross-kingdom host–pathogen communication and infection biology.

Article Title: Long noncoding RNAs cross kingdoms to broaden host–pathogen dialogue

Article References: Halilovic, L., & Jin, H. (2026). Long noncoding RNAs cross kingdoms to broaden host–pathogen dialogue. Cell Research. https://doi.org/10.1038/s41422-026-01289-7

Image Credits: AI Generated

DOI: 10.1038/s41422-026-01289-7

Keywords: long noncoding RNAs, host-pathogen interactions, cross-kingdom RNA, infection biology, antiviral immunity, gene regulation, RNA therapeutics, plant pathology, viral replication, interferon signaling, host-induced gene silencing, Cell Research

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