During viral infection and tissue injury, efficient immune clearance of infected or damaged cells is crucial for host defense and homeostasis. Here, we identify mitochondrial RNA (mtRNA) as a broad-spectrum damage-associated molecular pattern (DAMP) that coordinates antiviral and damage-related immune clearance. Through an integrative approach combining in vitro cellular assays and multi-strain murine models, we demonstrate that viral infection and cellular stress promote POLRMT-dependent mtRNA synthesis and its release into the cytosol through BAX/mPTP-mediated mitochondrial pores. Once released, mtRNA activates the MAVS signaling pathway, triggering a robust type I interferon response that operates independently of the cGAS-STING axis. Notably, viruses exploit a negative feedback loop for immune evasion: type I interferon upregulates the exoribonuclease PNPT1, which degrades cytosolic mtRNA and thereby dampens the mtRNA-MAVS axis. Critically, pharmacological inhibition of PNPT1 with lanthanum chloride (LanC), combined with BH3 mimetics that relieve the BCL-2-mediated blockade of BAX/BAK pores, synergistically reactivates mtRNA release and restores antiviral immunity. This dual strategy demonstrates potent antiviral and anti-fibrotic efficacy in preclinical models without significant toxicity. Our findings establish the mtRNA-MAVS axis as a central, broadly applicable immune surveillance pathway and provide a mechanistic framework for developing therapies that overcome both viral immune evasion and the limitations of current STING-targeted agonists.
Mingfu Tian, Guangli Li, Zelin Chai et al.· Cell Death & Disease· 0 citations
The COVID-19 pandemic has substantially reshaped population humoral immunity. However, whether individuals in the post-pandemic era have developed broader cross-neutralizing antibody responses against diverse coronaviruses remains unclear. To address this question, we evaluated serum neutralizing activity in 869 individuals from Wuhan, China, including 78 pre-pandemic samples collected in 2017 and 791 post-pandemic samples collected in 2025. Compared with pre-pandemic sera, post-pandemic sera exhibited enhanced neutralizing activity against multiple sarbecoviruses and the merbecovirus MjHKU4r-CoV-1, with mean viral inhibition increasing by 1.7% to 76.5% at a 1:20 serum dilution, most prominently against clade 1b sarbecoviruses. In contrast, no appreciable enhancement was observed against endemic human alphacoronaviruses or MERS-CoV. Neutralizing responses were strongly correlated across sarbecoviruses, particularly within clade 1b. Antigenic mapping showed that genetic relatedness did not reliably predict antigenic relationships, as Pangolin-GD, Pangolin-GX, and Khosta-2 were genetically more divergent yet antigenically closer to ancestral SARS-CoV-2 (D614G) than contemporary SARS-CoV-2 variants. Notably, both cohorts robustly neutralized Khosta-2, primarily through S1-directed antibodies, suggesting pre-existing cross-reactive immunity induced by endemic human coronaviruses that was further boosted by SARS-CoV-2 exposure. Collectively, these findings demonstrate that post-pandemic sera exhibit enhanced cross-neutralizing antibody responses predominantly against sarbecoviruses, potentially strengthening population immunity against related zoonotic sarbecoviruses and increasing the immunological barrier to their emergence in humans.
Shixiong Zhou, Chunhai Liu, Weiyong Liu et al.· Journal of Infection· 0 citations
