Host-derived lactic acid disrupts IFN efficacy via antiviral inhibition and proinflammatory amplification

Mingfu Tian; Siwei Chen; Ju Huang; Yan Tan; Xuan Wang; Meng Li; Jianyong Zhu; Moran Li; Hongli Guo; Xu Li; Zelin Chai; Li Shan; Yuhang Fu; Yijun Tang; Ziyi Zhang; Min Li; Congcong Huang; Na Wang; Weixing Du; Lina Sun; Kailang Wu; Qiang Tu; Ke Lan; Zhixin Liu

doi:10.1038/s41467-026-76000-w

. 2026 Jul 27;17:9085. doi: 10.1038/s41467-026-76000-w

Host-derived lactic acid disrupts IFN efficacy via antiviral inhibition and proinflammatory amplification

Mingfu Tian ^1,^2,^#, Siwei Chen ^1,^2,^#, Ju Huang ^1,^2,^#, Yan Tan ³, Xuan Wang ^1,³, Meng Li ³, Jianyong Zhu ³, Moran Li ^1,³, Hongli Guo ^1,³, Xu Li ², Zelin Chai ², Li Shan ^1,³, Yuhang Fu ^3,^4,⁵, Yijun Tang ¹, Ziyi Zhang ^1,^4,⁵, Min Li ¹, Congcong Huang ¹, Na Wang ¹, Weixing Du ³, Lina Sun ⁷, Kailang Wu ², Qiang Tu ^6,^✉, Ke Lan ^2,^✉, Zhixin Liu ^1,^2,^3,^4,^5,^✉

PMCID: PMC13518924 PMID: 42649175

Abstract

Circulating emerging viruses endanger public health. Type I interferons (IFNs) confer robust preclinical antiviral efficacy yet face incompletely defined clinical hurdles: narrow therapeutic windows, suboptimal activity and severe adverse events. Herein, we show that IFNs confer antiviral protection exclusively upon pre-infection administration. Once infection is established, IFNs are ineffective yet induce prominent adverse effects, with host-derived lactic acid (LAC) as the key mediator: it promotes viral immune evasion, impairs IFN therapeutic efficacy, triggers inflammatory storms, and elicits adverse reactions. Mechanistically, LAC suppresses IFN activity via membrane receptor-mediated Silent Information Regulator 1 (SIRT1) upregulation and synergizes with IFNs to hyperactivate Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B cells (NF-κB), initiating cytokine storms and forming an “antiviral failure-inflammatory amplification” feedback loop. Based on this mechanism, we develop a combinatorial therapy of IFNs plus an U.S. Food and Drug Administration (FDA)-approved lactate dehydrogenase inhibitor. This regimen reverses LAC-mediated IFN suppression, mitigates inflammation, and achieves dual “antiviral + anti-inflammatory” benefits. Notably, it retains robust efficacy even in late-stage infections, overcoming IFN monotherapy drawbacks and addressing the core bottleneck restricting IFN clinical application. Our study identifies LAC as a pivotal target for broad-spectrum antiviral development and provides a potential strategy to combat emerging viral pandemics.

Subject terms: Infection, Virus-host interactions, Inflammation, Viral infection

This study identifies host-produced lactic acid as a critical factor limiting the efficacy of IFN treatment after viral infection. Combining IFN with stiripentol, an approved LDH inhibitor, restores antiviral activity and alleviates inflammation in viral infection models.

Introduction

Driven by accelerating globalization and ongoing ecological alterations, viral infections have emerged as a major disruptive threat to global public health. Frequent cross-species transmission and global viral pandemics not only pose a life-threatening risk to human health, leading to substantial morbidity and mortality, but also trigger systemic public health crises with profound socioeconomic impacts^1,2. Although vaccination and antiviral interventions offer effective approaches to contain known epidemic viruses, their inherent limitations—narrow viral tropism, susceptibility to escape mutants, and a development cycle that lags behind viral evolution—render them ineffective against emerging and unknown viral pathogens. Thus, the development of broad-spectrum antiviral agents that are independent of specific viral types and possess pan-inhibitory activity has become a core imperative in global public health. This holds important strategic value for constructing a pre-emptive defense barrier against emerging viral infections and safeguarding global public health security.

Within the host’s immune regulatory network against viral infections, interferons (IFNs) hold a central role as the primary known broad-spectrum antiviral factors^3,4, exerting potent inhibitory effects on diverse viruses regardless of viral species. Extensive preclinical research studies have demonstrated robust antiviral activity of IFNs in both in vitro cellular systems and in vivo animal models. For instance, pretreatment with recombinant IFN-α reduces influenza virus titers by 10²–10³-fold in MDCK cells⁵, through targeting viral RNA replication and protein translation. Conversely, IFN-α/β receptor-deficient mice succumb to lethal infection within 3–5 days following low-dose challenge with vesicular stomatitis virus (VSV) or Semliki Forest virus (SFV), with tissue viral loads elevated by 10³–10⁴- fold relative to wild-type littermates. In contrast, wild-type mice rapidly induce IFN responses to clear the virus within 72 h, with 100% survival⁶. During the COVID-19 pandemic, IFNs similarly exhibited significant antiviral potential, with multiple in vitro and in vivo studies confirming their efficacy in suppressing viral replication and mitigating host tissue damage. Collectively, these findings establish IFNs as indispensable effector molecules of innate immunity, thereby providing a theoretical and experimental foundation for the development of IFN-based broad-spectrum antiviral strategies—addressing the unmet global public health need highlighted earlier.

However, a profound discrepancy persists between the potent broad-spectrum antiviral potential of IFNs in preclinical studies and their limited clinical utility⁷. Currently, their clinical indications are highly restricted—approved only for a handful of conditions, including chronic hepatitis B (CHB), chronic hepatitis C (CHC), and hairy cell leukemia^8–11. Even for Hepatitis C Virus (HCV), IFNs are not first-line therapy and are reserved for specific patient cohorts meeting strict eligibility criteria¹². More critically, for acute viral infections with higher incidence and broader public health impact (e.g., acute influenza, COVID-19, and dengue fever), IFNs are not recommended for routine use; instead, their application is hampered by suboptimal efficacy¹³ and elevated risk of adverse events^14–16. For instance, while IFN-α treatment shortens viral shedding by 1–2 days in acute influenza patients, it fails to substantially alleviate clinical manifestations such as fever and cough, and may induce adverse reactions including headache, fatigue, and myelosuppression¹⁷. In early acute COVID-19, despite in vitro and animal studies demonstrating viral replication inhibition by IFN-α/λ, multicenter randomized controlled trials (RCTs) show no improvement in hospitalization or severe disease progression rates among mild cases. For severe cases, IFN therapy may even exacerbate lung injury via excessive inflammatory activation, worsening clinical outcomes¹⁸. The core regulatory mechanisms underlying this stark divide between IFN’s preclinical promise and clinical performance remain incompletely defined, highlighting an urgent need for systematic mechanistic investigations to facilitate the rational clinical deployment of IFNs.

Emerging evidence indicates that the clinical limitations of IFNs stem from multifaceted factors. Animal studies have confirmed that the protective effects of IFNs against infections such as SARS-CoV and MERS-CoV are strictly dependent on prophylactic administration or early post-infection intervention¹⁹. However, due to limitations in viral detection technologies and patient presentation timelines, early clinical intervention is rarely achievable, resulting in missed optimal treatment windows. Mechanistically, IFNs exert antiviral effects primarily by activating the JAK-STAT pathway—inducing antiviral effector molecule expression to suppress viral replication, while regulating the activation and differentiation of dendritic cells and T cells to constrain excessive inflammation²⁰. By the time acute viral infection patients seek clinical care, however, viruses have already completed initial replication, immune responses are initiated, and some patients have entered a phase of hyperinflammation. At this stage, IFN therapy not only loses its antiviral efficacy but also abnormally triggers inflammatory responses, further exacerbating disease severity²¹. Although backed by some clinical studies, the causes of IFN therapeutic failure and adverse effects remain unclear, with no effective countermeasures available. Elucidating the mechanisms underlying IFN therapeutic failure and adverse effects in late-stage treatment is critical for optimizing IFN usage strategies, expanding clinical applications, and developing broad-spectrum antiviral agents, thus offering novel therapeutic directions for addressing current and future emerging viral pandemics.

To address this key scientific question, we integrated analyses of clinical samples, and cell/animal models of multi-viral infections, demonstrating that host-derived LAC produced following established viral infection is the central driver of IFN therapeutic failure. Lactate not only directly suppresses IFN antiviral activity but also induces cytokine storms in the presence of IFNs, exerting dual effects that exacerbate host damage and undermine clinical outcomes. Mechanistically, LAC directly inhibits IFN antiviral signaling transduction via activating cell membrane receptors and downstream SIRT1 signaling. Concurrently, in synergy with IFNs, LAC potently activates the NF-κB pathway to induce inflammatory storms, forming a double negative feedback loop characterized by “antiviral failure and enhanced inflammation”. Based on this mechanism, we developed a specific combination therapy of IFN plus the LAC dehydrogenase inhibitor stiripentol—an FDA-approved antiepileptic drug. This regimen effectively reduces host LAC production, reverses LAC-mediated antiviral suppression and proinflammatory effects, and achieves the dual benefit of “antiviral activity + inflammation control” with IFN therapy. Successfully overcoming some clinical limitations of IFNs, this combined therapy improves late-stage treatment efficacy and reduces side effects, providing a novel strategy for the development of broad-spectrum antiviral agents and offering new therapeutic prospects for combating current and future viral pandemics.

Results

Interferon treatment loses efficacy and induces a proinflammatory response in the context of established viral infection

As a central effector molecule of the innate immune network, interferons (IFNs) are well-recognized key broad-spectrum antiviral agents. Their potent antiviral activity, independent of viral species, has been fully validated both in vitro cell systems and in vivo murine models. However, a stark contrast exists between the robust antiviral potential of IFNs in preclinical studies and their severe clinical limitations. Currently, clinical indications of IFNs are extremely narrow—approved only for a few disorders such as CHB and CHC, where type I IFN-α serves as the standard therapeutic subtype, and often not as first-line therapy options. For acute viral infections with high incidence and broad impact—including influenza and COVID-19—IFNs are not recommended for routine use due to limited efficacy and elevated risk of adverse events. To date, the mechanisms underlying IFN therapeutic failure and adverse effects remain elusive, and no effective solutions exist to address this clinical dilemma, which greatly hinders the full realization of their clinical potential and the development of broad-spectrum antiviral strategies.

To systematically investigate the core mechanisms limiting the clinical utility of IFNs and define the critical time window for IFN-α intervention, we established multiple virus-infected cell models (Fig. 1A). By varying the timing of treatment and validating across multiple viruses and cell types, we elucidated its mode of action and universality. We selected three distinct viruses covering RNA and DNA genotypes: influenza A virus (H1N1), vesicular stomatitis virus (VSV), and herpes simplex virus type 1 (HSV-1). H1N1 is a highly prevalent human RNA virus with frequent mutations and limited clinical intervention options. VSV serves as a versatile laboratory RNA virus with broad cellular tropism. HSV-1, a representative DNA virus with latent infection properties, was further included to validate the generality of our findings across divergent viral types. Combined results showed that pretreatment with 2 nM IFN-α2a 2 h prior to infection effectively suppressed viral replication, whereas IFN-α antiviral activity was significantly attenuated once infection was established (Fig. 1 and Fig. S1). Specifically, pre-infection IFN-α pretreatment (−2 h) markedly inhibited the replication of influenza A virus (H1N1), VSV and HSV-1 in human non-immune A549 cells, reducing viral RNA and protein expression levels. This effect was consistently validated in immune cells (murine peritoneal macrophages, PM) and other primary cells (murine lung fibroblasts, MLF) (Fig. 1B, C and S1A–D). In contrast, IFN-α administration following viral infection significantly impaired antiviral efficacy, with even early post-infection treatment (4 h) resulting in reduced antiviral activity. (Fig. 1B, C and S1A–D). Furthermore, considering the proinflammatory potential of IFNs, we investigated this aspect. Results indicated that IFN-α pretreatment significantly suppressed virus-induced secretion of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) (Fig. 1D and Fig. S1E). However, after infection was established, IFN-α therapy not only lacked anti-inflammatory effects but also significantly exacerbated inflammatory responses at later stages, particularly in influenza virus-infected cells (Fig. 1D and Fig. S1E). These findings clearly demonstrate that IFN antiviral efficacy is strictly time-dependent: optimal antiviral effects are only achieved when administered pre-infection. Following established viral infection, therapeutic efficacy is drastically diminished and accompanied by proinflammatory adverse effects—an observation independent of virus and cell type, with substantial generality.

To further validate the in vivo relevance of in vitro findings, we recapitulated the experimental design in murine models (Fig. 1E). Mice were infected with different viruses and treated with IFN-α either pre-infection or post-infection, with systematic analysis of viral replication and pathological damage across infected tissues. Results demonstrated that compared to pre-infection pretreatment, IFN-α administration following infection significantly reduced antiviral potency. Even treatment initiated one day post-infection showed compromised efficacy, with later treatments correlating with weaker antiviral activity (Fig. 1F and Fig. S1F, G). In contrast, IFN-α pretreatment effectively suppressed viral replication in mice (Fig. 1F and Fig. S1F, G). More importantly, compared to infection alone, post-infection IFN-α therapy significantly exacerbated inflammatory responses in the liver and lung tissues of mice, inducing more severe histopathological damage and inflammatory cell infiltration (Fig. 1G, H and Fig. S2A–C). Conversely, IFN-α pretreatment effectively inhibited viral replication, significantly attenuating inflammatory responses and histopathological damage (Fig. 1E–H and Figs. S1F, G and S2). This pattern was consistently observed across different viral infection models and tissue types, confirming its in vivo generality.

In summary, our study demonstrates that IFN-α administration prior to viral infection fully exerts its antiviral effects while significantly reducing inflammatory responses and virus-induced histopathological damage. In contrast, IFN-α therapy initiated after viral infection is established not only results in drastically diminished antiviral activity but also exacerbates inflammatory responses and tissue injury. Notably, this phenomenon exhibits broad generality across different viral infection models, cell types, and in vivo tissues. Fundamentally, the prophylactic intervention models of “pre-infection pretreatment” or “concomitant administration” used in preclinical studies are not clinically feasible, as prophylactic pre-infection use is rarely achievable, and optimal timing is difficult to determine. Clinical interventions for diagnosed patients typically occur after infection is established, where treatment induces a double negative effect of “antiviral failure and enhanced side effects”—this constitutes the core reason why preclinical IFN efficacy cannot be fully recapitulated in clinical practice.

Established viral infection suppresses IFN-α signaling transduction

The antiviral effects of IFN-α are primarily mediated by its binding to interferon receptors, leading to activation of the downstream JAK-STAT signaling pathway and subsequent induction of the expression of core antiviral factors, including MX1²² and OAS1²³. To delineate whether LAC interferes with IFN-α signaling at the receptor level or via downstream effectors, we assessed IFNAR1 protein abundance in cells treated with IFN-α alone or in combination with LAC. LAC treatment did not alter IFNAR1 expression (Fig. S3A), demonstrating that LAC acts downstream of the interferon receptor to regulate IFN-α signaling. Consistent with this finding, we observed a significant attenuation of IFN-α antiviral activity following established viral infection. We therefore hypothesized that impaired JAK-STAT signaling transduction following infection is the key mechanism underlying IFN-α therapeutic failure.

To test this hypothesis, we administered IFN-α at two critical time points (12 and 24 h) following established influenza, VSV or HSV-1 infection (Fig. 2A, C and Fig. S3B), using direct IFN-α treatment (without viral infection) as a control. Results showed that IFN-α failed to effectively activate the JAK-STAT signaling pathway following established viral infection in both non-immune cells (A549, MLF) and immune cells (PM). In contrast, IFN-α treatment efficiently activated this pathway and its downstream effectors in normal, uninfected cells. Specifically, following infection with different viruses, the phosphorylation of STAT1—a key upstream transducer in the IFN signaling pathway—was significantly suppressed (Fig. 2B, D and Fig. S4A). Concurrently, the expression levels of downstream core interferon-stimulated genes (ISGs), including ISG15, MX1, IFIT1, and OAS1, were markedly downregulated (Figs. S3C, D and S4B, C). These findings demonstrate that impaired JAK-STAT signaling transduction following established viral infection is the core mechanism of IFN-α antiviral failure. This regulatory effect was consistent across different viruses and cell types, indicating broad generality.

To further validate these findings in vivo, we established a murine model of H1N1 influenza virus infection. Mice were treated with IFN-α (200 ng per mouse) post-infection, and lung tissues were collected for analysis (Fig. 2E). In vivo results were fully consistent with in vitro observations: compared to IFN-α treatment in uninfected mice, IFN-α treatment following viral infection failed to effectively activate the JAK-STAT signaling pathway in mouse lung tissues. Expression of key downstream effector genes (ISG15, MX1, IFIT1, and OAS1) was significantly reduced, ultimately limiting IFN-α antiviral efficacy (Fig. 2F). These in vivo data confirm that established viral infection specifically suppresses IFN-α-mediated JAK-STAT signaling transduction and downstream effector expression.

In summary, through integrated in vitro and in vivo experiments, this study demonstrates that IFN-α fails to effectively activate the JAK-STAT signaling pathway following established viral infection—this constitutes the key reason for its diminished antiviral potency. Importantly, this mechanism exhibits generality across different cell types and viral infection models.

Lactic acid mediates the suppression of IFN-α antiviral signaling after viral infection

Prior studies have confirmed that IFN-α-mediated JAK-STAT signaling is significantly suppressed following established viral infection, and this inhibitory effect is conserved across multiple cell types and viral infection models. This suggests the existence of a universal regulatory mechanism that transcends infection contexts and cellular backgrounds to impair the antiviral function of the IFN pathway.

To elucidate the molecular mechanism underlying this universal suppression, we performed transcriptomic sequencing on VSV-infected PM cells. In the present study, an in-depth analysis was conducted on the most significantly upregulated genes following infection. Combined with the focused mining of differentially expressed genes (DEGs) and the results of TOP20 pathway enrichment analysis, our findings revealed that: after viral infection, in addition to the significant activation of immune-related pathways, glucose metabolism-related pathways were also significantly upregulated, among which the glycolysis pathway-related genes exhibited the most prominent changes in expression(Fig. 3A–C), indicating that the glycolytic pathway is prominently activated by viruses. To verify the causal link between aberrant glucose metabolism and JAK-STAT pathway suppression, we pretreated A549 and PM cells with key upstream/downstream glycolytic inhibitors (2-deoxy-D-glucose [2-DG], lactate dehydrogenase inhibitor oxamate, and pyruvate transport inhibitor UK-5099), followed by IFN-α stimulation during viral infection (Fig. 3D). Results demonstrated that inhibiting early glycolytic steps and lactate dehydrogenase effectively restored IFN-α-mediated JAK-STAT signaling activation(Fig. 3E, F), indicating that the impaired IFN-α responsiveness in the late phase of viral infection is closely associated with lactate dehydrogenase, a key downstream glycolytic enzyme.

Fig. 3 — A Gene set enrichment analysis (GSEA) depicting the top 20 enriched pathways in VSVG-infected PM cells versus mock (n = 3 biological replicates). B GSEA enrichment plot for the Hallmark Glycolysis pathway in VSVG-infected PM cells (n = 3 biological replicates). C Heatmap showing glycolysis-related gene expression in VSVG-infected PM cells (n = 3 biological replicates). D Schematic illustrating the effects of glycolysis inhibitor 2-DG, LDH inhibitor oxamate, and pyruvate transport inhibitor UK-5099 on glycolysis. E Western blot analysis of core JAK-STAT signaling proteins in IFN-α-treated A549 cells and PMs, with or without glycolysis inhibition by 2-DG. F RT-PCR detection of JAK-STAT downstream antiviral genes (MX1, OAS1) in VSV-infected PMs treated with IFN-α alongside 2-DG, oxamate, or UK-5099. Data were mean ± SD; n = 3 biologically independent cell batches. One-way ANOVA (two-tailed). ns no significant, ∗p < 0.05, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001. G Intracellular LAC concentrations in VSV/H1N1-infected A549 cells and MLFs. Data were mean ± SD; n = 3 biologically independent cell batches. One-way ANOVA (two-tailed). ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001. H Serum LAC levels in VSV/H1N1-infected mice. Data were mean ± SD; n = 4 biologically independent C57BL/6J mice. One-way ANOVA (two-tailed). ∗∗∗p < 0.001 and ∗∗∗∗p < 0.0001. I Blood LAC analysis in clinical cohorts: LAC levels of COVID-19 patients (n = 210 biologically independent subjects) vs healthy controls (n = 58 biologically independent subjects), Unpaired two-tailed Student’s t-test for two-group comparisons; longitudinal LAC detection in influenza patients (n = 23 biologically independent subjects) on Day 0 and Day 3 post admission. Data were mean ± SD; One-way ANOVA (two-tailed). ns no significant, ∗∗p < 0.01, ∗∗∗∗p < 0.0001. J Western blot analysis of JAK-STAT pathway factors in cells treated with LAC combined with IFN-α. K Schematic of in vivo LAC and IFN-α administration in mice (n = 4 per group). L Western blot and densitometric quantification of JAK-STAT upstream factors in LAC/IFN-α treated mice. Data were mean ± SD; n = 4 biologically independent C57BL/6J mice. One-way ANOVA (two-tailed). ∗∗p < 0.01. Source data are provided as a Source Data file.

Lactate dehydrogenase (LDH) primarily catalyzes the metabolism of pyruvate to lactate, whereas inhibition of LDH restores interferon (IFN) activity (Fig. 3E, F). Building on this observation, we further investigated the role of lactate in suppressing IFN function. We found that intracellular LAC levels increased progressively over time following viral infection, with a significant elevation observed as early as the acute phase of infection (Fig. 3G)—consistent with the early impairment of IFN-mediated antiviral activity following infection (Fig. 1 and Fig. S1). Furthermore, in murine models, serum LAC levels were significantly elevated in virus-infected mice (Fig. 3H). More importantly, analysis of clinical samples confirmed the pathological relevance of this phenomenon: COVID-19 patients exhibited significantly higher LAC levels relative to healthy individuals (physiological normal concentration of lactate, 0.5–1.6 mmol/L) (Fig. 3I, left). Dynamic monitoring of LAC levels in influenza patients revealed a marked upward trend 3 days after positive infection detection, with no significant change at initial positive infection detection (Fig. 3I, right)—consistent with the progressive elevation of LAC induced by viral infection. Collectively, these results from cellular, animal, and clinical studies consistently demonstrate that viral infection induces a significant increase in host LAC levels, with clear clinical relevance.

Based on these observations, we propose a central hypothesis: Lactate derived from glucose metabolism is the key effector inhibiting IFN-α-mediated JAK-STAT signaling activation during viral infection. Notably, lactate exerts concentration-dependent effects (physiological vs. supraphysiological). Elevated lactate (exceeding physiological levels) was detected in our cellular models, murine specimens, and clinical samples post-infection, with concentrations reaching up to 10 mmol/L in subsets of patients and mice (Fig. 3G–I). To better reflect clinical practice—where interferon therapy is typically initiated after infection establishment, when patients already exhibit elevated lactate (Fig. 3I)—we used supraphysiological lactate concentrations in our treatment regimens, and interferon treatment was given after LAC treatment. A549 cells, PMs, and MLFs were pretreated with 10 mM LAC for 24 h, followed by IFN-α stimulation. Results demonstrated that LAC directly and significantly suppressed IFN-α-mediated JAK-STAT signaling activation. Specifically, in the presence of LAC, IFN-α-induced phosphorylation of STAT1 (a key upstream molecule in the pathway) and the expression of downstream core antiviral genes (ISG15, MX1, IFIT1, and OAS1) were significantly inhibited across multiple cell types (Fig. 3J and Fig. S5A–C). These findings clearly confirm that elevated host LAC induced by viral infection directly inhibits IFN signaling transduction, thereby impairing host antiviral capacity. To further define the regulatory specificity of lactate toward innate immune signaling, we subsequently detected additional core components of the JAK-STAT cascade and several parallel signaling pathways. Neither the protein abundance of STAT2 and IRF9 nor the activation status of MAPK, PI3K and mTOR pathways was markedly altered upon lactate exposure (Fig. S6A). Of note, phosphorylated IRF9 was hardly detectable under our experimental conditions, which is consistent with previous studies showing that IRF9 functions mainly relying on nuclear translocation instead of phosphorylation modification. Combined with our nuclear and cytoplasmic fractionation results, we further confirmed that lactate prominently blocks IFN-α-triggered STAT1 nuclear translocation (Fig. S6B). Collectively, these data indicate that lactate selectively interferes with STAT1 phosphorylation and subsequent nuclear translocation to restrain STAT1-dependent signaling transduction, rather than inducing non-specific suppression of broader immune-related cascades. This specific inhibitory characteristic further explains the targeted modulation of IFN-α antiviral responses by lactate.

To verify the in vivo generality of this mechanism, we reproduced the experiments in murine models (Fig. 3K). Results were fully consistent with in vitro observations: LAC significantly suppressed IFN-α-mediated JAK-STAT signaling activation in mice (Fig. 3L and Fig. S6C). Compared to direct IFN-α treatment, the presence of LAC reduced STAT1 phosphorylation levels and significantly inhibited the expression of downstream antiviral genes (ISG15, MX1, IFIT1, and OAS1) in mouse lung tissues.

In summary, this study demonstrates that established viral infection specifically induces excessive LAC production in the host. As a key regulatory molecule, LAC directly impairs the antiviral efficacy of IFN-α by targeting and inhibiting IFN-α-mediated JAK-STAT signaling activation. This regulatory mechanism is valid across multiple cell types and murine in vivo models. Furthermore, the consistent elevation of LAC levels in clinical patients with COVID-19, influenza, and other infections indicates that LAC is not merely a metabolic byproduct of infection but a key factor contributing to viral immune escape and disease progression—further highlighting the generality and clinical significance of this mechanism.

Lactic acid triggers the proinflammatory effects of interferon

Prior studies, along with our own data, have established that IFN therapy significantly exacerbates inflammation following established viral infection (Fig. 1). Given that LAC levels are progressively elevated in cells, murine models, and clinical patients over the course of infection (Fig. 3D–L), and that LAC is a key regulatory factor inhibiting the antiviral activity of IFN-α (Fig. 3 and Figs. S5 and S6), we hypothesized that LAC may contribute to disease progression by amplifying IFN-α-induced inflammatory responses—prompting targeted investigations.

We first performed correlation analyses on clinical samples from influenza and COVID-19 patients. LAC levels in patients were significantly positively correlated with inflammatory markers (interleukin-6 [IL-6], high-sensitivity C-reactive protein [CRP]) and tissue damage markers (creatine kinase-MB [CK-MB], lactic acid dehydrogenase [LDH]) (Fig. 4A). This clinical association between elevated LAC, inflammation, and tissue injury provided a foundation for mechanistic inquiry. To define the central role of LAC in inflammatory regulation, we further investigated the inflammatory response characteristics of virus-infected cells in the presence of LAC (Fig. 4B). Results showed that compared to viral infection or IFN-α alone, LAC treatment significantly promoted the expression of key proinflammatory cytokines, including IL-1β, IL-1α, IL-6, and TNF-α (Fig. 4C and Fig. S7A–D)—a phenomenon conserved across different viral infections and multiple cell types. To further systematically clarify the dose-dependent effect of LAC on viral replication, we performed a broader concentration gradient validation. A gradient of LAC concentrations ranging from 0 to 20 mM was applied to VSV- and H1N1-infected A549 cells, covering physiological and pathological lactate concentrations in vivo. Consistent with our previous findings, LAC steadily facilitated the replication of both VSV and H1N1 throughout the detected concentration range (Fig. S7E), further verifying the robustness and generalizability of the pro-viral characteristic of LAC.

To validate the in vivo relevance of these in vitro findings, we established a murine model of viral infection combined with LAC treatment (Fig. 4D). Results showed that compared to viral infection alone, LAC treatment significantly enhanced viral replication (Fig. 4E and Fig. S8A, B)—consistent with our previous conclusion that “LAC impairs IFN-α antiviral activity by targeting and inhibiting IFN-α-mediated JAK-STAT signaling” (Fig. 3). More critically, LAC treatment significantly exacerbated tissue inflammatory responses and pathological damage in mice compared to viral infection alone (Fig. 4F, G an Fig. S8C–E). These in vivo experiments further confirm that LAC not only inhibits IFN-α antiviral effects but also amplifies its proinflammatory activity, accelerating disease progression.

Since the NF-κB signaling pathway is the core mediator of proinflammatory cytokine production, we further evaluated the regulatory effect of IFN-α treatment on cellular inflammatory responses in the presence of LAC (Fig. 4H). Strikingly, LAC significantly enhanced IFN-α-induced phosphorylation of p65—a key upstream molecule in the NF-κB signaling pathway (Fig. 4I and Fig. S9A–D)—and upregulated the expression of downstream IL-1β, IL-1α, IL-6, and TNF-α. In contrast, treatment with LAC or IFN-α alone failed to significantly activate the NF-κB pathway or the expression of related proinflammatory cytokines (Fig. 4I and Fig. S9A–D). This reveals that IFN-α alone is insufficient to drive substantial inflammation, but in the presence of LAC, it acquires potent proinflammatory capacity, even capable of inducing a cytokine storm in the absence of infection.

To further validate these findings, exclude confounding factors such as viruses, and confirm the direct regulatory role of LAC in IFN-α proinflammatory effects, we established a murine model of LAC combined with IFN-α treatment in the absence of viral infection (Fig. 4J). Results showed that IFN-α monotherapy had no significant effect on mouse survival and did not induce obvious tissue damage or inflammatory responses (Fig. 4K–M). In contrast, compared to the IFN-α monotherapy group, the LAC + IFN-α combination group exhibited significantly reduced mouse survival (Fig. 4K), with severe inflammatory infiltration and pathological damage in liver tissues (Fig. 4L, M). This critical evidence further confirms that LAC can directly trigger IFN-α‘s proinflammatory effects, inducing cytokine storms and exacerbating tissue damage even without viral involvement.

In summary, this study clearly demonstrates that LAC is a key regulatory factor underlying IFN-α therapeutic failure and adverse effects. It exacerbates virus-associated pathological damage and impairs clinical outcomes through a dual mechanism¹: impairing IFN-α antiviral activity by inhibiting IFN-α-mediated JAK-STAT signaling, thereby promoting viral replication²; directly triggering IFN-α‘s proinflammatory potential to induce cytokine storms, exacerbating tissue inflammation and pathological damage, ultimately leading to host death—even in the absence of viral infection. This finding not only reveals the key mechanism underlying the adverse effects of IFN-α in clinical therapy but also suggests that LAC levels may serve as a potential biomarker for evaluating IFN-α treatment safety. It provides an important theoretical basis and clinical reference for optimizing antiviral therapeutic strategies and improving patient prognosis.

Lactic acid attenuates antiviral JAK-STAT signaling through PKA-SIRT1 axis activation

Having identified LAC as a key driver of impaired interferon-α (IFN-α) antiviral function and exacerbated tissue inflammatory damage, this study further dissected its underlying molecular mechanism. Given reports that LAC can modulate target protein function via direct lactylation modification, we first investigated whether it modulates JAK-STAT pathway activation by inducing lactylation of signal transducer and activator of transcription 1 (STAT1). A549 and PM cells were treated with gradient concentrations of LAC, and results showed no significant differences in STAT1 protein expression across groups (Fig. 5A, B), indicating that LAC does not affect STAT1 protein synthesis or stability. Furthermore, HA-tagged STAT1 recombinant plasmid was overexpressed in 293 T cells, and co-immunoprecipitation (Co-IP) assays confirmed that STAT1 was not lactylated (Fig. 5C). These findings clearly rule out the possibility that LAC regulates STAT1 function via direct lactylation modification.

Fig. 5 — A, B Western blot analysis of STAT1 in cells (A549, PMs) treated with the indicated concentrations of LAC. C Co-immunoprecipitation (Co-IP) analysis of STAT1 lactylation modification. Panlac: Rabbit monoclonal anti-L-lactyl lysine, used for detecting lysine L-lactylation modification. D Western blot analysis of *STAT1* phosphorylation (*p-STAT1*) and *ISG15* expression in cells (A549 and PMs) co-treated with GPR132-PKA pathway inhibitors (H-89, Telmisartan), MCT1 inhibitor (AZD3965), LAC, and IFN-α. E Western blot analysis of STAT1 phosphorylation (*p-STAT1*) and *ISG15* expression in cells (A549, PM) co-treated with GPR132-PKA-SIRT1 pathway inhibitors (Compound C, EX527), p300 inhibitor (C646), LAC, and IFN-α. F Western blot and RT-PCR analyses of *SIRT1* in cells (A549, PM) stimulated with LAC. Data were presented as mean ± SD; n = 3 biologically independent cell batches. Unpaired two-tailed Student’s t-test for two-group comparisons. ∗p < 0.05 and ∗∗p < 0.01. G Schematic of in vivo LAC administration. Mice (n = 4 per group) were stimulated with LAC at 0 and 8 h, followed by the collection of liver and kidney tissues for detection and analysis. H Western blot and RT-PCR analyses of *SIRT1* in LAC-stimulated mice. Data were presented as mean ± SD; n = 4 biologically independent C57BL/6J mice. Unpaired two-tailed Student’s t-test for two-group comparisons. ∗p < 0.05 and ∗∗p < 0.01. I Western blot analysis and densitometric quantification of the key upstream factor of the JAK-STAT signaling pathway (*p-STAT1*) in mice co-treated with GPR132-PKA-SIRT1 pathway inhibitors (H-89, EX527), LAC, and IFN-α. Data were presented as mean ± SD; n = 3 biologically independent C57BL/6 J mice. One-way ANOVA (two-tailed). ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗∗p < 0.0001. J) Schematic model summarizing the molecular mechanism by which infection-induced LAC suppresses JAK-STAT antiviral signaling pathway and exacerbates tissue inflammatory damage. This panel was created with BioRender.com under CC BY 4.0 publication license. Source data are provided as a Source Data file.

LAC has also been shown to exert indirect regulatory effects by activating multiple signaling pathways—for example, initiating the downstream GPR132-PKA pathway via G protein-coupled receptor 132 (GPR132)^24–26, activating the PKA signaling pathway after transmembrane transport mediated by monocarboxylate transporter 1 (MCT1)²⁷, or regulating gene transcription via the histone acetyltransferase p300 as a key substrate for histone lactylation²⁸ (Fig. S10A). However, which component of these signaling pathways mediates LAC’s inhibitory effect on the IFN pathway remains unclear. To address this question, A549 and PM cells were pretreated with the GPR132 antagonist Telmisartan, PKA inhibitor H-89, or MCT1 inhibitor AZD3965, followed by co-stimulation with LAC and IFN-α. Results demonstrated that targeted inhibition of the GPR132-PKA pathway and MCT1 in A549 and PM cells significantly restored STAT1 phosphorylation levels and the expression of ISG15 (Fig. 5D). This demonstrates that LAC’s inhibition of the IFN pathway is dependent on MCT1-mediated transmembrane transport, GPR132 receptor binding, and downstream PKA signaling activation—with PKA downstream molecules potentially serving as key regulatory nodes.

To identify the key downstream mediator of PKA, we screened downstream factors. Previous studies have shown that PKA downstream molecules can regulate biological functions by activating AMPK²⁹ and SIRT1³⁰. Concomitantly, lactate can also directly induce histone lactylation via p300. We pretreated cells and lung with the AMPK inhibitor Compound C, SIRT1 inhibitor EX527, or p300 inhibitor C646, followed by co-stimulation with LAC and IFN-α. Results showed that only the SIRT1 inhibitor EX527 effectively restored IFN-α-mediated JAK-STAT pathway activation (Fig. 5E and Fig. S10B), while AMPK and p300 inhibitors had no such effect—confirming that SIRT1 is the key downstream molecule mediating LAC’s inhibition of the IFN pathway. Meanwhile, high-throughput sequencing analysis of bronchoalveolar lavage fluid (BALF) from COVID-19 patients and healthy controls demonstrated a significant upregulation of SIRT1 in the patient cohort compared with other SIRT families. (Fig. S10C). In addition, we further detected SIRT1 expression in peripheral blood mononuclear cells (PBMCs) isolated from healthy donors and influenza-infected patients, and found that SIRT1 expression was markedly elevated in patients compared with healthy individuals (Fig. S10D). Previous studies have demonstrated that SIRT1, an NAD+-dependent deacetylase, negatively regulates the JAK-STAT pathway by promoting STAT1 acetylation and inhibiting its phosphorylation³¹, but its role in LAC-mediated IFN inhibition has not been reported. We found that LAC treatment significantly upregulated SIRT1 protein expression in multiple cell lines, including A549 and PM (Fig. 5F). At the in vivo level, SIRT1 expression was also significantly increased in mouse liver and kidney tissues following intraperitoneal LAC injection (Fig. 5G, H). Consistent in vitro and in vivo results confirm that LAC specifically induces excessive SIRT1 expression. Lastly, mice were pretreated with the PKA inhibitor H-89 and the SIRT1 inhibitor EX527, followed by co-stimulation with LAC and IFN-α. Our results demonstrated that LAC significantly suppressed the activation of the JAK-STAT signaling pathway in mouse lung tissues, while H-89 and EX527 effectively reversed this LAC-mediated inhibitory effect (Fig. 5I).

To further verify the PKA-SIRT1 regulatory axis and exclude the off-target effects of pharmacological inhibitors, we first performed siRNA-mediated genetic interference under virus-free conditions. Knockdown of MCT1, PKA or SIRT1 completely abolished the inhibitory effect of LAC on JAK-STAT signaling, and robust pathway activation was still retained even under LAC and IFN-α co-treatment (Fig. S11A, B). We further validated this axis in authentic viral infection models. In VSV and H1N1 infected cells, siRNA knockdown of SIRT1, PKA and LDHA markedly restored endogenous IFN-α-triggered STAT1 phosphorylation and simultaneously inhibited viral replication (Fig. S11C, D), confirming the indispensable role of the PKA-SIRT1 axis under real pathological conditions.

In summary, this study demonstrates that excessive LAC accumulation induced by viral infection can specifically upregulate SIRT1 expression via PKA activation, inhibiting STAT1 phosphorylation and blocking the JAK-STAT antiviral signaling pathway—ultimately impairing IFN-α antiviral efficacy and exacerbating tissue inflammatory damage (Fig. 5J). This mechanism not only reveals a potential strategy for viral escape from host antiviral immunity but also provides a key pathophysiological explanation for the poor antiviral response and inflammation-related adverse effects (e.g., hepatorenal impairment) observed in clinical IFN-α therapy. Viral infection patients often exhibit abnormally elevated LAC metabolism in clinical settings, and the LAC-SIRT1-JAK-STAT regulatory axis identified in this study suggests that targeting LAC metabolism may serve as a potential intervention strategy to improve IFN-α therapeutic response and reduce treatment-related damage.

Combined administration of stiripentol and IFN-α synergistically inhibits viral replication and inflammatory responses

Previous studies, including our own, have clearly identified LAC as a key regulatory factor that impairs IFN-α antiviral efficacy and exacerbates virus-induced tissue inflammatory damage. Based on this, targeted inhibition of LAC production may serve as an effective strategy to restore IFN-α antiviral activity and alleviate inflammation-related damage associated with viral replication.

Building on these findings, we developed a specific combined therapeutic regimen of IFN-α plus the LAC dehydrogenase (LDH) inhibitor stiripentol. As an FDA-approved clinical drug for the treatment of severe myoclonic epilepsy in infants³², stiripentol’s classical mechanism of action involves regulating γ-aminobutyric acid (GABA)-ergic nervous system function to inhibit excessive neuronal excitation^33,34. Critically, it also inhibits the property of inhibiting the activity of LDH—a key enzyme in previous studies have confirmed. Previous studies have confirmed that stiripentol can downregulate the lactylation modification level of NBS1 protein by inhibiting LAC production in gastric cancer cells, reduce tumor cell DNA repair capacity, and thereby overcome tumor radioresistance and chemoresistance³⁵.

Stiripentol was verified to effectively suppress LAC production induced by viral infection in cells and mice (Fig. 6A). Subsequently, we treated it with stetamentanol as shown in the figure (Fig. 6B). Results showed that compared to pre-infection IFN-α monotherapy, IFN-α alone almost lost its antiviral activity after infection was established. In contrast, stiripentol treatment effectively rescued IFN-α-mediated JAK-STAT signaling activation post-infection and significantly inhibited viral replication (Fig. 6C)—confirming the core role of the combined therapy in reversing IFN-α antiviral failure.

To further verify whether the pharmacological effect of stiripentol is specifically dependent on LAC regulation, we performed lactate add-back rescue experiments. Exogenous lactate supplementation effectively reversed the restorative effect of stiripentol on IFN-α-JAK-STAT signaling (Fig. S12A), confirming that the protective action of stiripentol is strictly lactate-dependent. In addition, our previous LDHA knockdown results further support that LDH/LAC acts as the key downstream mediator responsible for stiripentol function. Collectively, these data demonstrate that stiripentol restores IFN-α efficacy mainly through reducing endogenous LAC production, rather than via non-specific off-target effects.

To evaluate the in vivo potential of the combined therapy, we established a murine viral infection model. After infection was established, mice were treated with IFN-α monotherapy, stiripentol monotherapy, or their combination (Fig. 6D). Results confirmed that post-infection, IFN-α monotherapy failed to effectively activate the JAK-STAT signaling pathway or induce antiviral gene expression (Fig. 6E). Stiripentol monotherapy partially restored IFN-α antiviral function and upregulated the expression of antiviral factors (Fig. S12C). Strikingly, the IFN-α + stiripentol combination group exhibited the optimal effect, even when administered post- infection, it still drove IFN-α to efficiently activate the JAK-STAT antiviral signaling pathway, significantly induce antiviral factor expression, and inhibit viral replication (Fig. 6E and Fig. S12C)—fully validating the in vivo antiviral efficacy of the combined therapy.

Given previous evidence that LAC can directly trigger IFN-α’s proinflammatory effects, inducing cytokine storms and exacerbating tissue damage even in the absence of virus, we further evaluated the regulatory role of the combined therapy on post-infection inflammatory responses. Results showed that compared to the high levels of inflammatory cytokines in the IFN-α monotherapy group, stiripentol monotherapy partially downregulated inflammatory cytokine expression. In contrast, the combination therapy group significantly suppressed infection-induced cytokine storms (Fig. S13A, B), demonstrating potent anti-inflammatory activity. Histopathological analysis further revealed that compared to viral infection alone, IFN-α monotherapy post-infection significantly increased inflammatory neutrophil infiltration in mouse liver and lung tissues, inducing more severe histopathological damage (Fig. 6F, G and Fig. S13C–E). Stiripentol monotherapy had no significant improvement in tissue damage or inflammatory neutrophil infiltration. However, compared to the infection-only group and each monotherapy group, the combination therapy group showed significantly reduced inflammatory neutrophil infiltration and markedly alleviated histopathological damage in liver and lung tissues (Fig. 6F, G and Fig. S13C–E)—achieving synergistic benefits of “antiviral activity + inflammation control”.

A core bottleneck in current clinical application of IFN-α lies in the impracticality of prophylactic intervention strategies widely used in preclinical studies (e.g., “pre-infection pretreatment” or “concomitant administration”). Prophylactic administration prior to infection cannot be routinely performed clinically, nor can the optimal timing of administration be accurately determined. Clinical therapeutic interventions for confirmed patients mostly initiate after infection is established, where IFN-α monotherapy often leads to a dualseed dilemma of “antiviral failure + enhanced inflammatory side effects”. The core advantage of this combined therapy is its significant efficacy even when intervention is initiated post-infection—completely breaking the strict restriction of traditional IFN-α therapy on administration timing. It effectively reverses LAC-mediated IFN-α antiviral inhibition and proinflammatory adverse effects, overcomes some core limitations of clinical IFN-α application, and significantly improves late-stage infection treatment efficacy while reducing the side effects of monotherapy. This not only provides a novel strategy for the development of broad-spectrum antiviral drugs but also offers new therapeutic options and directions for addressing current and future viral pandemics—presenting a practical solution to the long-standing problem of limited clinical application of IFN-α in antiviral therapy.

Discussion

The global spread of emerging and re-emerging viral pandemics continues to pose a severe threat to public health security. While vaccines and traditional antiviral drugs have provided partial solutions for combating known viruses, their inherent limitations have become increasingly prominent: vaccines require a long development cycle, are vulnerable to viral mutation and escape, and can only target specific viral subtypes; traditional antiviral drugs mostly target specific viral proteins, facing challenges such as rapid development of drug resistance and ineffectiveness against unknown viruses. These shortcomings collectively highlight the urgency and strategic significance of developing broad-spectrum antiviral agents that are relatively independent of viral types.

Since the first discovery of interferons (IFNs) by Isaacs and Lindenmann in 1957³⁶, their pivotal role as core effector molecules of the host innate antiviral immunity has been fully validated through decades of research, making them a central target for studies on antiviral immune mechanisms and clinical translation. In contrast to their prominent role in preclinical research, the current clinical application of IFNs is extremely limited. They are only approved for a few diseases, such as chronic hepatitis B and chronic hepatitis C, and are rarely the first-line treatment of choice. For acute viral infections with high incidence and wide impact, such as acute influenza and COVID-19, IFNs are not recommended for routine use; instead, they are strictly restricted due to limited efficacy and high risk of adverse reactions. To date, the core mechanisms underlying IFN clinical failure and side effects remain unclear, and there is a lack of effective solutions to address this clinical dilemma, which has greatly hindered the full realization of their clinical value and the development of broad-spectrum antiviral strategies.

Through systematic validation using clinical samples, multi-viral infection cell models, and murine models, this study found that the prophylactic intervention modes such as “pre-infection pretreatment” or “concomitant administration” widely used in preclinical research are rarely feasible in clinical practice. Prophylactic use before infection is difficult to implement, and the optimal timing of administration is even more challenging to determine. Clinical therapeutic interventions for confirmed patients mostly occur at the established infection stage, where drug administration results in a dual negative effect of “antiviral failure + enhanced side effects”—this is the core reason why the basic efficacy of IFNs cannot be translated into clinical outcomes. Mechanistically, this study identified host-derived LAC induced by viral infection as the key driver of the clinical bottleneck of IFN therapy, and clarified its dual regulatory mechanism of “LAC-SIRT1-JAK-STAT/LAC-NF-κB”. Ultimately, a transformative combination therapy of IFN plus stiripentol was developed, providing a novel strategy for broad-spectrum antiviral treatment.

This study confirmed that IFN therapeutic efficacy is highly dependent on the timing of infection, which provides a key entry point for explaining the discrepancy between its preclinical and clinical efficacy. In vitro experiments demonstrated that IFN pretreatment can effectively inhibit the replication of various viruses and reduce inflammatory responses in multiple cell types; however, administration after the establishment of viral infection not only significantly impairs antiviral activity but also exacerbates cytokine storms and tissue damage. In vivo experiments further verified the universality of this rule, suggesting that clinical therapeutic interventions for confirmed patients after established infection are the core cause of poor IFN efficacy. In-depth studies revealed that virus-induced LAC at concentrations far exceeding the normal physiological level serves as the central factor mediating the abnormal function of IFN. Our experimental model was established to simulate clinical infection scenarios. Particularly, with respect to the lactate stimulation intervention step, we designed the treatment sequence based on the clinical pathological process in which lactate is first induced upon infection prior to interferon administration. Subsequent experimental validation confirmed that interferon alone failed to trigger an inflammatory response; instead, lactate produced during viral infection acts as the critical synergistic factor mediating the induction of inflammatory reactions. Transcriptome analysis and metabolic detection confirmed that different viral infections universally activate the host glycolytic pathway, leading to a significant increase in LAC levels in cells and serum—this phenomenon was validated in clinical samples from COVID-19 and influenza patients, highlighting its pathological relevance. This further indicates that LAC, previously considered a mere metabolic byproduct, may play a key role in infection-related disease progression. Mechanistic experiments clarified that LAC impairs IFN therapeutic effects through a dual mechanism¹: LAC induces excessive SIRT1 expression via the GPR132-PKA signaling pathway, thereby inhibiting STAT1 phosphorylation, blocking the activation of the JAK-STAT antiviral signaling pathway, and directly impairing the viral inhibitory capacity of IFNs²; LAC synergizes with IFNs to efficiently activate the NF-κB pathway, inducing storms of proinflammatory cytokines such as IL-1β and IL-6, and exacerbating tissue damage. Notably, combined treatment with LAC and IFNs can induce inflammatory damage and mouse death even in the absence of viral infection, confirming that this proinflammatory effect is independent of viral replication and serves as a key inducer of IFN clinical side effects. This mechanism not only clarifies the critical role of LAC in regulating IFN antiviral function but also reveals the central role of SIRT1 in LAC-mediated IFN signaling inhibition, providing a clear molecular target for targeted intervention.

Accumulating evidence has demonstrated that type I interferon-mediated innate immune responses exhibit obvious gender differences, which are closely associated with differential expression of X-linked genes and the regulatory effects of estrogen³⁷. Moreover, glycolytic metabolism and SIRT1-related signaling activities are also regulated by sex hormones³⁸, implying potential gender heterogeneity in lactate-mediated IFN signaling suppression. In the present study, all core in vivo functional validations were primarily performed in male mice to maintain consistent experimental conditions and unified phenotypic results. Nevertheless, we further conducted parallel verification experiments in female mice (Fig. S14). Consistent with the findings obtained in male mice, viral infection could trigger an obvious elevation of serum lactate in female individuals, and elevated lactate was capable of effectively restraining IFN-α-dependent antiviral signaling transduction. Meanwhile, the combined therapeutic strategy consisting of stiripentol and IFN-α also exerted stable regulatory effects on immune response and viral restriction in female mice. These results suggest that the core lactate-centered regulatory mechanism and the synergistic antiviral regimen established in this study possess good universality across different genders. Considering the main research focus and research scope of this work, we did not carry out in-depth exploration on sex-specific molecular regulatory discrepancies and clinical data stratified by gender, and further systematic research in this direction will be carried out in follow-up studies.

Based on the above mechanisms, this study innovatively developed a “IFN combined with LAC dehydrogenase (LDH) inhibitor stiripentol” combination therapy, realizing a complete chain of “mechanism-target-drug”. As an FDA-approved clinical drug, stiripentol’s property of inhibiting LDH activity and blocking LAC production was first applied in antiviral therapy. In vitro and in vivo experiments confirmed that even when intervention is initiated after the establishment of viral infection, this combination therapy can effectively reduce LAC levels, restore IFN-mediated JAK-STAT pathway activation, and significantly inhibit viral replication; meanwhile, it can potently block LAC-IFN synergistically induced cytokine storms, alleviate hepatopulmonary pathological damage, and achieve dual benefits of “efficient antiviral activity + precise inflammation control”. The core advantage of this regimen lies in breaking the strict restriction of IFN on administration timing, solving the practical clinical problem of “difficulty in early intervention”. Additionally, the clinical application basis of stiripentol reduces translational risks, enabling the rapid advancement of clinical research. The aforementioned combination therapy provides novel targets and technical strategies for the development of broad-spectrum antiviral agents. Beyond its substantial antiviral activity, IFN also exerts potent effects in contexts such as antitumor therapy and antibacterial infection. Previous studies have demonstrated that LAC is similarly highly expressed in the tumor microenvironment and infected lesions^39,40, indicating that LAC may also interact with interferons. Based on this observation, the relevant mechanism of action and combined therapeutic regimen proposed herein are also expected to open new avenues and provide innovative strategies for the treatment of tumors and other diseases. This offers novel therapeutic approaches and drug options for addressing existing and future unknown diseases as well as viral pandemics, holding significant clinical translational value and public health implications.

Methods

Comprehensive information regarding the reagents, consumables, antibodies, and other relevant materials utilized in the experiments is available in Supplementary Data 1.

Patient samples

All clinical samples were collected from Shiyan People’s Hospital, Hubei University of Medicine. A total of 210 patients diagnosed with COVID-19, 23 patients with influenza, and 58 healthy control subjects were enrolled in this study, all of whom were admitted to the hospital between January 2022 and December 2023. Peripheral blood samples were collected from all enrolled participants to detect lactate levels, inflammatory factor levels, and myocardial injury markers. Blood sampling for COVID-19 and influenza patients was performed on Day 1 and Day 3 after disease onset, and all peripheral blood samples from patients with confirmed COVID-19 or influenza were collected within 7 days after pathogen confirmation and hospitalization. All healthy control subjects were inpatients admitted for routine physical examination. At the time of blood collection, none of the healthy controls presented with respiratory symptoms, fever, viral infection, or inflammatory diseases. Additionally, all subjects exhibited negative respiratory virus nucleic acid test results to rule out potential occult infection.

Cells

In this study, various cell lines, including HEK293T, VERO, A549, and MDCK, were obtained from the American Type Culture Collection (ATCC). Primary peritoneal macrophages were isolated from male mice 5 days following intraperitoneal injection of thioglycollate broth medium. Lung fibroblasts were isolated by mincing male mouse lungs and digesting them with Hank’s solution. These were cultured in DMEM media. All media were supplemented with 10% fetal bovine serum and 100 U/mL penicillin/streptomycin. The cells were maintained at 37 °C in a humidified atmosphere with 5% CO₂. It’s noteworthy that all cell lines used in the study were regularly tested and confirmed to be free from mycoplasma contamination.

Viruses

Influenza H1N1-PR stocks were propagated in Serum Free Medium for MDCK Cells. VSV-GFP propagated in Serum Free Medium for VERO Cells.

Animals

All mice were maintained in a specific-pathogen-free facility with a 12-h light/dark cycle, constant temperature of 22 ± 2 °C and humidity of 50 ± 5%, and were allowed ad libitum access to food and water. Six-week-old male C57BL/6J wild-type mice were purchased from Changsheng Biotechnology (Liaoning, China). Mice were infected with the H1N1 virus via intranasal instillation and with the VSV virus via intraperitoneal injection. Additionally, mice were administered IFN-α, LAC and stiripentol via intraperitoneal injection for stimulation. All animal experiments were approved by the Institutional Animal Care and Use Committee (IACUC) of Hubei University of Medicine. All animal experiments were approved by the Institutional Animal Care and Use Committee (IACUC) of Hubei University of Medicine (approval ID: Hubei Univ. Med. Animal Welfare No. 2025-Shen-092). All animal procedures were carried out following the ARRIVE guidelines and the national laboratory animal welfare regulations of China.

Infection and transfection

For infection, A549, PM and MLF cells were infected with DMEM containing viruses with a multiplicity of infection (MOI). For transfection, plasmids were transfected by using Lipofectamine 3000 according to the manufacturer's instructions, and cells were harvested or further treated as indicated.

Immunoblotting (IB)

Cells were harvested and lysed with lysis buffer (150 mM NaCl, 50 mM Tris-HCl [PH 7.4], 1% Triton X-100, 1 mM EDTA [pH 8.0], 0.1% SDS supplemented with a protease inhibitor cocktail) for 30 min at 4 °C. The supernatants were collected by centrifugation at 12,000×g for 25 min at 4 °C. Protein concentrations were determined using the Bradford method. Equal amounts of protein were separated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred onto a polyvinylidene fluoride (PVDF) membrane. After blocking with 5% non-fat milk dissolved in TBST (phosphate-buffered saline with 0.1% Tween-20), it was incubated with the primary Abs, followed by horseradish peroxidase-conjugated goat anti-rabbit or anti-mouse IgG. The proteins were detected on a Bio-Rad ChemiDoc imaging system by using enhanced chemiluminescence (ECL).

Immunoprecipitation (IP)

For protein–protein interactions assays, cells were lysed in RIPA lysis buffer (150 mM NaCl, 0.5% NP-40, and 5 mM EDTA) containing a mixture of protease inhibitors (Roche). Primary antibodies were incubated with Protein A/G agarose beads for 30 min at room temperature, followed by incubation with cell lysates for 3 h with rotation at room temperature (RT). The beads were washed four times with lysis buffer and analyzed by IB.

Immunohistochemistry(IHC) analysis

Thin sections of hepatic and pulmonary tissues were treated to remove paraffin and restore hydration. They were then placed in a sodium citrate buffer with a pH of 6.0 for antigen retrieval and allowed to cool. Following this, endogenous peroxidase activity was suppressed for a duration of 10 min through the application of a 0.3% (v/v) hydrogen peroxide solution in methanol. After being incubated with a 10% goat serum blocking solution for 30 min, the samples were subjected to Ly-6G (1:200) antibodies overnight. Following two rounds of washing, the samples underwent a 30 min incubation at room temperature with a secondary antibody diluted at a ratio of 1:100. The cell nuclei were subsequently stained with hematoxylin following the color development using the DAB kit.

RNA extraction and quantitative RT-PCR

Total RNA was extracted from cells or tissues that have been processed with Trizol. About 0.6 μg of total RNA was reverse transcribed to synthesize cDNA by HiScript II Q RT SuperMix, using ChamQ SYBR qPCR Master Mix for qPCR. Real-time quantitative PCR was run in duplicate using iTaq SYBRGreen (Bio-Rad), following the manufacturer’s instructions. Data were presented as relative mRNA abundance normalized to GAPDH expression in each sample (Primer sequence information is shown in Supplementary Data 2).

RNA-sequencing and data processing

Virus-infected cells were immediately transferred into 1 ml Trizol, snap-frozen in liquid nitrogen, and kept at −80 °C. RNA extraction was performed by GeneDenovo (QIAGEN, China). RNA integrity number (RIN) was determined using the Agilent RNA 6000 Nano Kit for quality control, and all samples were above 8.5. After sequencing, samples were aligned to the Ensembl_release111 Genome. For the pathway analysis, GSEA (4.2.3) was used to identify pathway enrichment among the total genes expressed in the PM cells infected with VSVG or mock.

Lactate measurements

L-lactic acid levels in cells and mouse tissues were measured using the L-lactic acid assay kit according to the manufacturer’s instructions.

Nucleo-cytoplasmic fractionation

Cells were rinsed twice with cold PBS. Cytoplasmic and nuclear protein fractions were isolated using a nuclear/cytosol fractionation kit per the manufacturer’s protocol. Briefly, cells were lysed sequentially with cytoplasmic extraction reagents on ice. After centrifugation, the cytoplasmic supernatant was collected. The remaining pellet was lysed with nuclear extraction buffer and centrifuged to obtain nuclear extracts. The prepared samples were applied for subsequent assays.

Enzyme-linked immunosorbent assay

Purified proteins were immobilized onto 96-well plates in a carbonate buffer (200 ng per well) and incubated at 4 °C overnight. After five washes with PBST (PBS with 0.05% Tween-20), blocking was performed using 1% BSA in PBST. Subsequently, mouse serum samples were added and incubated at room temperature for 2 h. Following five times of washing, secondary antibodies were added for 1 h. Then, the HRP diluted in PBST with 1% BSA was added and incubated for an additional hour. After five times washing, the TMB substrate was applied, and the reaction was stopped by adding 1 M H₂SO₄. Absorbance at 450 nm was measured and recorded. The obtained data were analyzed using GraphPad Prism 9.

H&E staining of liver and lung tissues

Hepatic and pulmonary tissues were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned into 4-μm slices. Sections were deparaffinized in xylene, hydrated through a graded ethanol series, stained with filtered Harris hematoxylin for 8 min and 0.5% eosin Y for 3 min, followed by dehydration and clearing. Stained sections were mounted with neutral balsam and visualized under a light microscope.

Statistics and reproducibility

In this study, an unpaired two-tailed Student’s t-test was adopted for comparisons between two groups, and one-way analysis of variance (one-way ANOVA) was performed for multi-group comparisons without further post hoc correction for multiple comparisons. This statistical scheme was selected as our experimental design centered on pre-specified comparisons of core groups, instead of exploratory pairwise comparisons covering all experimental groups. The reproducibility of partial western blot results was validated via biological replicates within each experimental group, repeated viral infection treatments and independent cellular replicate experiments. All P values presented in this manuscript match the corresponding statistical tests. The primary conclusions of this work are statistically robust and fully substantiated by the experimental datasets. Complete frequentist statistical outputs, including test statistics, degrees of freedom, exact P values, effect sizes and 95% confidence intervals for all comparative analyses, have been provided in the supplementary Source Data file for comprehensive verification.

Ethics statement

All experimental protocols of the present study strictly complied with all applicable ethical regulations. This research was formally reviewed and approved by the Ethics Committee of Shiyan People’s Hospital Affiliated to Hubei University of Medicine (Ethics Approval Number: 2025-PR-052). All procedures involving human clinical samples were carried out in full accordance with the ethical standards laid down in the Declaration of Helsinki. Prior to sample collection, both verbal and written informed consent were acquired from every enrolled participant.

Reporting summary

Further information on research design is available in the Nature Portfolio Reporting Summary linked to this article.

Supplementary information

Supplementary Materials^{(3.4MB, pdf)}

41467_2026_76000_MOESM2_ESM.pdf^{(29.2KB, pdf)}

Description of Additional Supplementary File

Supplementary data 1^{(12.2KB, xlsx)}

Supplementary data 2^{(10.6KB, xlsx)}

Reporting summary^{(2.8MB, pdf)}

Transparent Peer Review file^{(4.5MB, pdf)}

Source data

source data^{(8.9MB, xlsx)}

Author contributions

K.L. and Z.L. contributed to the study concept and design. M.T., S.C., and J.H. carried out most of the experiments. X.W., M.L., J.Z., M.L., H.G., X.L., Z.C., S.L., Y.F., J.T., Z.Z., M.L., C.H., N.W., and W.D. analysed the data with help from K.L. and Z.L. contributed to the drafting of the manuscript. Q.T., L.S., K.W., and Y.T. contributed to the reagents. Q.T., J.W., and Z.L. contributed to editing the manuscript. All authors contributed to the article and approved the submitted version.

Peer review

Peer review information

Nature Communications thanks Shuofeng Yuan, Sebastian Schloer and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. A peer review file is available.

Funding

This work was supported by research grants from National Natural Science Foundation of China (32188101 and 32400131), Hubei Provincial Natural Science Foundation (2023BCB058 and 2026AFC0261), Natural Science Foundation of Hubei Provincial Department of Education (D20242105), China Postdoctoral Science Foundation (2024T170687, 2024M752482, and GZB20230541), the Open Research Fund of State Key Laboratory of Virology and Biosafety (SKLVKF2025014), Innovative Research Program for Graduates of Hubei University of Medicine (YC2026010) and the Hubei Provincial Training Program of Innovation and Entrepreneurship for Undergraduates (S202610929016 and X202610929055).

Data availability

All quantitative raw values underlying graphs are supplied as a Source Data file. RNA-seq data have been deposited in GEO under accession GSE325117. Individual de-identified clinical data are available from the corresponding author upon reasonable written request, subject to institutional ethical approval. Source data are provided with this paper.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

These authors contributed equally: Mingfu Tian, Siwei Chen, Ju Huang.

Contributor Information

Qiang Tu, Email: tuqiang1986@163.com.

Ke Lan, Email: klan@whu.edu.cn.

Zhixin Liu, Email: lzx20022456@126.com.

Supplementary information

The online version contains supplementary material available at 10.1038/s41467-026-76000-w.

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9.Shapiro, S. et al. mRNA cytokine profile in peripheral blood cells from chronic hepatitis C virus (HCV-infected patients: effects of interferon-alpha (IFN-alpha) treatment. Clin. Exp. Immunol.114, 55–60 (1998). [DOI] [PMC free article] [PubMed] [Google Scholar]
10.Waldmann, T. A. Cytokines in cancer immunotherapy. Cold. Spring. Harb. Perspect. Biol. 10, a028472 (2018). [DOI] [PMC free article] [PubMed]
11.Locke, M. C. et al. Interferon alpha, but not interferon beta, acts early to control chronic chikungunya virus pathogenesis. J. Virol.96, e0114321 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
12.Cooke, G. S. et al. Treatment options to support the elimination of hepatitis C: an open-label, factorial, randomised controlled non-inferiority trial. Lancet405, 1769–1780 (2025). [DOI] [PMC free article] [PubMed] [Google Scholar]
13.Finter, N. B. et al. The use of interferon-alpha in virus infections. Drugs42, 749–765 (1991). [DOI] [PMC free article] [PubMed] [Google Scholar]
14.Tannock, G. A. et al. A study of intranasally administered interferon A (rIFN-alpha 2A) for the seasonal prophylaxis of natural viral infections of the upper respiratory tract in healthy volunteers. Epidemiol. Infect.101, 611–621 (1988). [DOI] [PMC free article] [PubMed] [Google Scholar]
15.Galbraith, M. D. et al. Specialized interferon action in COVID-19. Proc. Natl. Acad. Sci. USA119, e2116730119 (2022). [DOI] [PMC free article] [PubMed]
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18.Kalil, A. C. et al. Efficacy of interferon beta-1a plus remdesivir compared with remdesivir alone in hospitalised adults with covid-19: a double-bind, randomised, placebo-controlled, phase 3 trial. Lancet Respir. Med.9, 1365–1376 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
19.Wong, L. R. & Perlman, S. Immune dysregulation and immunopathology induced by SARS-CoV-2 and related coronaviruses - are we our own worst enemy? Nat. Rev. Immunol.22, 47–56 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
20.Randall, R. E. & Goodbourn, S. Interferons and viruses: an interplay between induction, signalling, antiviral responses and virus countermeasures. J. Gen. Virol.89, 1–47 (2008). [DOI] [PubMed] [Google Scholar]
21.Kim, Y. M. & Shin, E. C. Type I and III interferon responses in SARS-CoV-2 infection. Exp. Mol. Med.53, 750–760 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
22.Xiao, H. et al. The human interferon-induced mxa protein inhibits early stages of influenza a virus infection by retaining the incoming viral genome in the cytoplasm. J. Virol.87, 13053–13058 (2013). [DOI] [PMC free article] [PubMed] [Google Scholar]
23.Kristiansen, H. et al. Extracellular 2’−5’ oligoadenylate synthetase stimulates RNase l-independent antiviral activity: a novel mechanism of virus-induced innate immunity. J. Virol.84, 11898–11904 (2010). [DOI] [PMC free article] [PubMed] [Google Scholar]
24.Liu, W. et al. Lactate modulates iron metabolism by binding soluble adenylyl cyclase. Cell Metab.35, 1597–1612.e1596 (2023). [DOI] [PubMed] [Google Scholar]
25.Ngai, D., Schilperoort, M. & Tabas, I. Efferocytosis-induced lactate enables the proliferation of pro-resolving macrophages to mediate tissue repair. Nat. Metab.5, 2206–2219 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]
26.Cantó, C. et al. Ampk regulates energy expenditure by modulating NAD+ metabolism and SIRT1 activity. Nature458, 1056–1060 (2009). [DOI] [PMC free article] [PubMed] [Google Scholar]
27.Hahn, E. L., Halestrap, A. P. & Gamelli, R. L. Expression of the lactate transporter MCT1 in macrophages. Shock13, 253–260 (2000). [DOI] [PubMed] [Google Scholar]
28.Zhang, D. et al. Metabolic regulation of gene expression by histone lactylation. Nature574, 575–580 (2019). [DOI] [PMC free article] [PubMed] [Google Scholar]
29.Medina, E. A. et al. PKA/AMPK signaling in relation to adiponectin’s antiproliferative effect on multiple myeloma cells. Leukemia28, 2080–2089 (2014). [DOI] [PubMed] [Google Scholar]
30.Gerhart-Hines, Z. et al. The cAMP/PKA pathway rapidly activates SIRT1 to promote fatty acid oxidation independently of changes in NAD(+). Mol. Cell44, 851–863 (2011). [DOI] [PMC free article] [PubMed] [Google Scholar]
31.Yu, S. S. et al. Deacetylase sirtuin 1 mitigates type I IFN- and type II IFN-induced signaling and antiviral immunity. J. Virol.98, e0008824 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]
32.Chiron, C. et al. Stiripentol in severe myoclonic epilepsy in infancy: a randomised placebo-controlled syndrome-dedicated trial. Sticlo study group. Lancet356, 1638–1642 (2000). [DOI] [PubMed] [Google Scholar]
33.Fisher, J. L. The effects of stiripentol on GABA(A) receptors. Epilepsia52, 76–78 (2011). [DOI] [PMC free article] [PubMed] [Google Scholar]
34.Fisher, J. L. The anti-convulsant stiripentol acts directly on the GABA(A) receptor as a positive allosteric modulator. Neuropharmacology56, 190–197 (2009). [DOI] [PMC free article] [PubMed] [Google Scholar]
35.Chen, H. et al. Nbs1 lactylation is required for efficient DNA repair and chemotherapy resistance. Nature631, 663–669 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]
36.Isaacs, A. & Lindenmann, J. Virus interference. I. The interferon. Proc. R. Soc. Lond. B. Biol. Sci.147, 258–267 (1957). [PubMed] [Google Scholar]
37.Pujantell, M. & Altfeld, M. Consequences of sex differences in type I IFN responses for the regulation of antiviral immunity. Front. Immunol.13, 986840 (2022). [DOI] [PMC free article] [PubMed]
38.Tao, Z. & Cheng, Z. Hormonal regulation of metabolism-recent lessons learned from insulin and estrogen. Clin. Sci.137, 415–434 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]
39.Li, J. et al. Histone lactylation bridges metabolic reprogramming with chromatin-immune crosstalk in triple-negative breast cancer. Cancer Lett.639, 218227 (2025). [DOI] [PubMed] [Google Scholar]
40.Peng, X. et al. Lactic acid: the culprit behind the immunosuppressive microenvironment in hepatocellular carcinoma [J]. Biochim. Biophys. Acta Rev. Cancer1879, 189164 (2024). [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary Materials^{(3.4MB, pdf)}

41467_2026_76000_MOESM2_ESM.pdf^{(29.2KB, pdf)}

Description of Additional Supplementary File

Supplementary data 1^{(12.2KB, xlsx)}

Supplementary data 2^{(10.6KB, xlsx)}

Reporting summary^{(2.8MB, pdf)}

Transparent Peer Review file^{(4.5MB, pdf)}

source data^{(8.9MB, xlsx)}

Data Availability Statement

[CR1] 1.Del Rio, C., Collins, L. F. & Malani, P. Long-term health consequences of covid-19. JAMA324, 1723–1724 (2020). [DOI] [PMC free article] [PubMed] [Google Scholar]

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[CR8] 8.Asselah, T. et al. Interferon therapy for chronic hepatitis B. Clin. Liver Dis.11, 839–849 (2007). viii. [DOI] [PubMed] [Google Scholar]

[CR9] 9.Shapiro, S. et al. mRNA cytokine profile in peripheral blood cells from chronic hepatitis C virus (HCV-infected patients: effects of interferon-alpha (IFN-alpha) treatment. Clin. Exp. Immunol.114, 55–60 (1998). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR10] 10.Waldmann, T. A. Cytokines in cancer immunotherapy. Cold. Spring. Harb. Perspect. Biol. 10, a028472 (2018). [DOI] [PMC free article] [PubMed]

[CR11] 11.Locke, M. C. et al. Interferon alpha, but not interferon beta, acts early to control chronic chikungunya virus pathogenesis. J. Virol.96, e0114321 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR12] 12.Cooke, G. S. et al. Treatment options to support the elimination of hepatitis C: an open-label, factorial, randomised controlled non-inferiority trial. Lancet405, 1769–1780 (2025). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR13] 13.Finter, N. B. et al. The use of interferon-alpha in virus infections. Drugs42, 749–765 (1991). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR14] 14.Tannock, G. A. et al. A study of intranasally administered interferon A (rIFN-alpha 2A) for the seasonal prophylaxis of natural viral infections of the upper respiratory tract in healthy volunteers. Epidemiol. Infect.101, 611–621 (1988). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR15] 15.Galbraith, M. D. et al. Specialized interferon action in COVID-19. Proc. Natl. Acad. Sci. USA119, e2116730119 (2022). [DOI] [PMC free article] [PubMed]

[CR16] 16.Hayden, F. G. et al. Prevention of natural colds by contact prophylaxis with intranasal alpha 2-interferon. N. Engl. J. Med.314, 71–75 (1986). [DOI] [PubMed] [Google Scholar]

[CR17] 17.Davidson, S. et al. Ifnλ is a potent anti-influenza therapeutic without the inflammatory side effects of ifnα treatment. EMBO Mol. Med.8, 1099–1112 (2016). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR18] 18.Kalil, A. C. et al. Efficacy of interferon beta-1a plus remdesivir compared with remdesivir alone in hospitalised adults with covid-19: a double-bind, randomised, placebo-controlled, phase 3 trial. Lancet Respir. Med.9, 1365–1376 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR19] 19.Wong, L. R. & Perlman, S. Immune dysregulation and immunopathology induced by SARS-CoV-2 and related coronaviruses - are we our own worst enemy? Nat. Rev. Immunol.22, 47–56 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR20] 20.Randall, R. E. & Goodbourn, S. Interferons and viruses: an interplay between induction, signalling, antiviral responses and virus countermeasures. J. Gen. Virol.89, 1–47 (2008). [DOI] [PubMed] [Google Scholar]

[CR21] 21.Kim, Y. M. & Shin, E. C. Type I and III interferon responses in SARS-CoV-2 infection. Exp. Mol. Med.53, 750–760 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR22] 22.Xiao, H. et al. The human interferon-induced mxa protein inhibits early stages of influenza a virus infection by retaining the incoming viral genome in the cytoplasm. J. Virol.87, 13053–13058 (2013). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR23] 23.Kristiansen, H. et al. Extracellular 2’−5’ oligoadenylate synthetase stimulates RNase l-independent antiviral activity: a novel mechanism of virus-induced innate immunity. J. Virol.84, 11898–11904 (2010). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR24] 24.Liu, W. et al. Lactate modulates iron metabolism by binding soluble adenylyl cyclase. Cell Metab.35, 1597–1612.e1596 (2023). [DOI] [PubMed] [Google Scholar]

[CR25] 25.Ngai, D., Schilperoort, M. & Tabas, I. Efferocytosis-induced lactate enables the proliferation of pro-resolving macrophages to mediate tissue repair. Nat. Metab.5, 2206–2219 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR26] 26.Cantó, C. et al. Ampk regulates energy expenditure by modulating NAD+ metabolism and SIRT1 activity. Nature458, 1056–1060 (2009). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR27] 27.Hahn, E. L., Halestrap, A. P. & Gamelli, R. L. Expression of the lactate transporter MCT1 in macrophages. Shock13, 253–260 (2000). [DOI] [PubMed] [Google Scholar]

[CR28] 28.Zhang, D. et al. Metabolic regulation of gene expression by histone lactylation. Nature574, 575–580 (2019). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR29] 29.Medina, E. A. et al. PKA/AMPK signaling in relation to adiponectin’s antiproliferative effect on multiple myeloma cells. Leukemia28, 2080–2089 (2014). [DOI] [PubMed] [Google Scholar]

[CR30] 30.Gerhart-Hines, Z. et al. The cAMP/PKA pathway rapidly activates SIRT1 to promote fatty acid oxidation independently of changes in NAD(+). Mol. Cell44, 851–863 (2011). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR31] 31.Yu, S. S. et al. Deacetylase sirtuin 1 mitigates type I IFN- and type II IFN-induced signaling and antiviral immunity. J. Virol.98, e0008824 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR32] 32.Chiron, C. et al. Stiripentol in severe myoclonic epilepsy in infancy: a randomised placebo-controlled syndrome-dedicated trial. Sticlo study group. Lancet356, 1638–1642 (2000). [DOI] [PubMed] [Google Scholar]

[CR33] 33.Fisher, J. L. The effects of stiripentol on GABA(A) receptors. Epilepsia52, 76–78 (2011). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR34] 34.Fisher, J. L. The anti-convulsant stiripentol acts directly on the GABA(A) receptor as a positive allosteric modulator. Neuropharmacology56, 190–197 (2009). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR35] 35.Chen, H. et al. Nbs1 lactylation is required for efficient DNA repair and chemotherapy resistance. Nature631, 663–669 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR36] 36.Isaacs, A. & Lindenmann, J. Virus interference. I. The interferon. Proc. R. Soc. Lond. B. Biol. Sci.147, 258–267 (1957). [PubMed] [Google Scholar]

[CR37] 37.Pujantell, M. & Altfeld, M. Consequences of sex differences in type I IFN responses for the regulation of antiviral immunity. Front. Immunol.13, 986840 (2022). [DOI] [PMC free article] [PubMed]

[CR38] 38.Tao, Z. & Cheng, Z. Hormonal regulation of metabolism-recent lessons learned from insulin and estrogen. Clin. Sci.137, 415–434 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]

[CR39] 39.Li, J. et al. Histone lactylation bridges metabolic reprogramming with chromatin-immune crosstalk in triple-negative breast cancer. Cancer Lett.639, 218227 (2025). [DOI] [PubMed] [Google Scholar]

[CR40] 40.Peng, X. et al. Lactic acid: the culprit behind the immunosuppressive microenvironment in hepatocellular carcinoma [J]. Biochim. Biophys. Acta Rev. Cancer1879, 189164 (2024). [DOI] [PubMed] [Google Scholar]

PERMALINK

Host-derived lactic acid disrupts IFN efficacy via antiviral inhibition and proinflammatory amplification

Mingfu Tian

Siwei Chen

Ju Huang

Yan Tan

Xuan Wang

Meng Li

Jianyong Zhu

Moran Li

Hongli Guo

Xu Li

Zelin Chai

Li Shan

Yuhang Fu

Yijun Tang

Ziyi Zhang

Min Li

Congcong Huang

Na Wang

Weixing Du

Lina Sun

Kailang Wu

Qiang Tu

Ke Lan

Zhixin Liu

Abstract

Introduction

Results

Interferon treatment loses efficacy and induces a proinflammatory response in the context of established viral infection

Fig. 1. IFN-α fails to protect against established viral infection and promotes inflammation.

Established viral infection suppresses IFN-α signaling transduction

Fig. 2. Established viral infection suppresses IFN-α signaling transduction.

Lactic acid mediates the suppression of IFN-α antiviral signaling after viral infection

Fig. 3. Lactic acid mediates the suppression of IFN-α antiviral signaling after viral infection.

Lactic acid triggers the proinflammatory effects of interferon

Fig. 4. Lactic acid exacerbates virus-induced inflammatory responses.

Lactic acid attenuates antiviral JAK-STAT signaling through PKA-SIRT1 axis activation

Fig. 5. Lactic acid attenuates antiviral JAK-STAT signaling through PKA-SIRT1 axis activation.

Combined administration of stiripentol and IFN-α synergistically inhibits viral replication and inflammatory responses

Fig. 6. Combined administration of stiripentol and IFN-α synergistically inhibits viral replication and inflammatory responses.

Discussion

Methods

Patient samples

Cells

Viruses

Animals

Infection and transfection

Immunoblotting (IB)

Immunoprecipitation (IP)

Immunohistochemistry(IHC) analysis

RNA extraction and quantitative RT-PCR

RNA-sequencing and data processing

Lactate measurements

Nucleo-cytoplasmic fractionation

Enzyme-linked immunosorbent assay

H&E staining of liver and lung tissues

Statistics and reproducibility

Ethics statement

Reporting summary

Supplementary information

Source data

Author contributions

Peer review

Peer review information

Funding

Data availability

Competing interests

Footnotes

Contributor Information

Supplementary information

References

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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