Mitochondrial dysfunction due to myeloid TFAM loss limits senolytic efficacy in allergic airway inflammation

RATIONALE: Macrophages are key drivers of allergic airway inflammation, but the mitochondrial mechanisms regulating these responses remain incompletely defined. Mitochondrial transcription factor A (TFAM) is essential for mitochondrial DNA (mtDNA) maintenance and mitochondrial homeostasis. OBJECTIVES: To define the role of myeloid TFAM in mitochondrial stress, senescence, allergic airway inflammation, and response to senolytic therapy. METHODS: Allergic airway inflammation was induced with dust mite, ragweed, and Aspergillus (DRA) in myeloid-specific TFAM-deficient mice TFAMfl/flLysMcre and littermate controls. Inflammatory, remodeling, mitochondrial, and senescence-associated outcomes were assessed in vivo and in macrophage-based mechanistic studies, including human alveolar macrophages. ABT-263 was used to evaluate senolytic responsiveness. MEASUREMENTS AND MAIN RESULTS: Myeloid TFAM deficiency worsened DRA-induced airway inflammation, eosinophilia, goblet cell hyperplasia, and collagen deposition, and increased pulmonary inflammatory, cGAS-STING, and senescence-associated markers. TFAM-deficient macrophages showed reduced mitochondrial mass and mitochondrial gene expression, increased cytosolic mtDNA, and greater susceptibility to TGF-β-induced senescence. In human alveolar macrophages, IL-4 decreased TFAM expression and mtDNA content, increased cytosolic mtDNA, and induced senescence-associated genes. ABT-263 suppressed IL-4-induced senescence and inflammatory gene expression in macrophages and reduced eosinophilia and inflammatory mediator production in allergen-challenged control mice, but these effects were largely lost in TFAMfl/flLysMcre mice. CONCLUSIONS: Myeloid TFAM limits mtDNA stress, senescence-associated inflammation, and allergic airway pathology, and influences responsiveness to senolytic therapy.