Mitochondrial IRF3 drives pulmonary fibrosis by impairing mitophagy and triggering ferroptosis
Zhang Jiashu1, Liu Jingbao2, Fang Hua3
1Respiratory and Critical Care Medicine, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China; Key Laboratory of Hepatosplenic Surgery, Ministry of Education, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China.
Background:
Pulmonary fibrosis (PF) is a progressive, lethal lung disease with limited treatments. Although inflammation is involved, how it triggers specific oxidative cell death in epithelial cells remains unclear. The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is active in PF, but research has focused on its upstream inflammatory role. The function of its key effector, interferon regulatory factor 3 (IRF3), especially through non-canonical mechanisms, is largely unknown. We hypothesized that activated IRF3 translocates to mitochondria to disrupt quality control and promote ferroptosis, linking inflammation to fibrosis.
Methods:
We employed a bleomycin-induced mouse PF model and TGF-β-stimulated A549 cells. Techniques included molecular analyses (western blot, RT-qPCR, Co-IP), imaging (TEM, immunofluorescence), mitophagy flux assays, and measurement of ferroptosis markers (Fe2+, MDA). Interventions involved H151, si-IRF3, Ferrostatin-1, and Mdivi-1.
Results:
In PF, phosphorylated IRF3 translocated to mitochondria, interacting with PINK1 to impair mitophagy, shown by decreased PINK1, accumulated p62, and reduced LC3-II/LC3-I ratio. This triggered ferroptosis, evidenced by upregulated ACSL4, downregulated GPX4, elevated Fe2+/MDA, and mitochondrial damage. In TGF-β-stimulated A549 cells, IRF3 knockdown or STING inhibition restored mitophagy and suppressed ferroptosis. Mdivi-1 reversed si-IRF3's protection. In vivo, H151 treatment suppressed the IRF3-mitophagy-ferroptosis axis and alleviated PF.
Conclusions:
Mitochondrial IRF3 integrates cGAS-STING signaling with mitophagic dysfunction and ferroptosis to drive PF, revealing a novel therapeutic target.
Insights
Mitochondrial IRF3 links inflammation to ferroptosis in pulmonary fibrosis by impairing mitophagy. Targeting this IRF3-mitophagy-ferroptosis axis offers a novel therapeutic strategy for this lethal lung disease.
Area of Science:
- Cellular Biology
- Molecular Medicine
- Pathology
Background:
- Pulmonary fibrosis (PF) is a fatal lung disease with limited treatment options.
- The role of inflammation in triggering oxidative cell death in epithelial cells in PF is not fully understood.
- The cGAS-STING pathway is implicated in PF, but the non-canonical functions of its effector IRF3 remain largely unexplored.
Purpose of the Study:
- To investigate the role of activated IRF3 in mitochondria.
- To determine if IRF3 disrupts mitochondrial quality control and promotes ferroptosis.
- To establish a link between inflammation, mitophagy, and ferroptosis in the pathogenesis of PF.
Main Methods:
- Utilized a bleomycin-induced mouse PF model and TGF-β-stimulated A549 cells.
- Performed molecular analyses, imaging, mitophagy flux assays, and ferroptosis marker measurements.
- Intervened with H151, si-IRF3, Ferrostatin-1, and Mdivi-1 to assess pathway modulation.
Main Results:
- Phosphorylated IRF3 translocated to mitochondria in PF, impairing mitophagy by interacting with PINK1.
- This mitochondrial dysfunction triggered ferroptosis, indicated by altered key markers and mitochondrial damage.
- IRF3 inhibition or STING pathway blockade restored mitophagy and reduced ferroptosis in vitro and in vivo, with H151 treatment alleviating PF.
Conclusions:
- Mitochondrial IRF3 acts as a crucial integrator of cGAS-STING signaling, mitophagic dysfunction, and ferroptosis in PF.
- This pathway represents a novel mechanism driving disease progression.
- Targeting mitochondrial IRF3 presents a promising therapeutic avenue for pulmonary fibrosis.
More Related Videos
Related Concept Videos
01:19Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
01:16Necrosis
Morphological Manifestations of Necrosis
Necrotic cells show different types of morphological appearance depending on the type of tissue and infection. In coagulative necrosis, cells become...
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
01:30The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q...