Abstract
Objective
Environmental exposure and genetic mutations are key factors in the pathogenesis and exacerbation of fibrosis. This work maps the distribution ozone (O3) signals and examines the impact of exposure in lung remodeling.Materials and methods
Spatial transcriptomic and proteomic analyses were performed on CD68+ macrophages and CD45- non-immune cells from histologically distinct regions of air- or O3-exposed (0.8 ppm, 3 h) SP-C mutant lungs. Fibrosis was initiated by tamoxifen-mediated induction of a disease-linked Surfactant Protein (SP)-C gene mutation. The effects of O3 exposure prior or after SP-C induction were assessed via histology, flow cytometry, and immunohistochemistry.Results
Multi-omics analysis of O3 injury revealed spatially restricted and cell-specific responses, characterized by mitochondrial metabolism and antioxidant pathway enrichment in injured-region macrophages, while peri-injured cells displayed pro-survival and lipid metabolism signatures. O3 exposure induced senescence and cell-cycle regulatory signals in all CD45- cells, with peri-injured exhibiting additional metabolic and collagen remodeling pathways. Proteomics showed widespread phospho-signaling in CD45- cells, an effect restricted to peri-injured areas in CD68+ macrophages. O3 exposure in fibrosing SP-C mutant mice caused Ly6Chi monocyte influx at 3 days but dampened the expansion of CD4+/CD8+ T cell observed in the O3 exposed uninduced lung. Fibrotic remodeling, cell proliferation (Ki67), and immune composition were not influenced by O3 exposure at 7 days, though their combination increased mouse mortality and inflammatory cell activation (iNOS).Conclusion
These data identify O3 exposure as a modifier of regional inflammatory and stress-response pathways with modest effects on disease progression in the SP-C mutant lung.