N-myc and STAT interactor (NMI) drives poly(I:C)-induced pulmonary coagulopathy via STAT3-dependent tissue factor upregulation
Background
Viral pneumonia is a significant cause of mortality, often exacerbated by associated pulmonary coagulopathy. The precise upstream molecular drivers that initiate this coagulation cascade remain poorly understood, hindering the development of targeted therapies. Current standard-of-care often focuses on anticoagulation, but addressing the root cause of hypercoagulability could offer more effective intervention. This study investigates novel mechanisms contributing to thrombotic complications in virus-induced lung inflammation, specifically focusing on the STAT3 pathway and its role in TF expression.
Study Design
Researchers utilized a poly(I:C)-induced pneumonia model in mice to simulate viral lung inflammation. They integrated bulk and single-cell transcriptomics to identify key molecular signatures. Mechanistic evaluations involved Nmi knockout mice and pharmacological inhibition of STAT3 using Stattic. Endpoints included assessment of lung injury, tissue factor (TF) expression via qPCR and Western blot, and quantification of lung microthrombosis. The study also involved administering recombinant NMI to Nmi knockout mice to confirm its role.
Results
Transcriptomic analyses across human and murine viral pneumonia datasets revealed robust upregulation of N-myc and STAT interactor (NMI), which strongly correlated with coagulation markers. NMI was identified as a critical damage-associated molecular pattern (DAMP) promoting poly(I:C)-induced pulmonary coagulopathy. Mechanistically, extracellular NMI was found to activate alveolar epithelial STAT3 signaling, directly upregulating tissue factor (TF) to initiate the extrinsic coagulation cascade. This finding highlights a novel NMI-STAT3-TF axis. In vivo, Nmi ablation or pharmacological STAT3 inhibition with Stattic significantly attenuated lung microthrombosis and coagulopathy. This protective phenotype in Nmi knockout mice was reversed by recombinant NMI administration, confirming NMI's direct pro-coagulant role.
Nmiablation orSTAT3inhibition significantly attenuated lung microthrombosis and coagulopathy in the poly(I:C) model.
Key Findings
- NMI is robustly upregulated in human and murine viral pneumonia, correlating with coagulation markers.
- Extracellular NMI activates alveolar epithelial
STAT3signaling, directly upregulatingtissue factor (TF). Nmiablation or pharmacologicalSTAT3inhibition significantly attenuated lung microthrombosis and coagulopathy.- Recombinant NMI administration reversed the protective phenotype in
Nmiknockout mice, confirming its role.
Why It Matters
This research identifies a novel and critical NMI-STAT3-TF axis as a key contributor to pulmonary coagulopathy in viral pneumonia, offering a new therapeutic target. Targeting NMI or STAT3 could represent a preclinical strategy to manage thrombotic complications, potentially reducing mortality in severe viral lung infections. While still in preclinical animal models, these findings suggest that existing STAT3 inhibitors like Stattic could be repurposed or novel NMI-targeting agents developed. This could lead to protocols that modulate coagulation at an earlier, more upstream point than current anticoagulants, potentially improving outcomes for patients with severe viral pneumonia.
nmi
stattic
pulmonary-coagulopathy
viral-pneumonia
stat3-inhibitor
tissue-factor