Lung basement membranes are compositionally and structurally altered following resolution of influenza infection.

Identification of pathways preventing timely recovery from acute respiratory viral infection is under-studied but essential for long-term health. Using unbiased proteomics, we reveal an unexpected, reduction in lung basement membrane proteins 21 days after influenza infection when mice had symptomatically recovered. Basement membrane provides a critical scaffold for heterogeneous cell types and the proteins they secrete/express at the endothelial and epithelial barrier. Further peptide location fingerprinting analysis shows inherent structure-associated changes within core collagen IV and laminin components, particularly within the NC1 domains of collagen IV. Our results imply lingering damage to the basement membrane network despite symptomatic recovery from viral infection. Surprisingly, similar structure-associated changes in laminin and collagen IV components are also observed in non-infected, aged mice indicating that inflammation-driven basement membrane degeneration may contribute to tissue ageing. Interestingly, macrophages in regions deficient in basement membrane express collagen IV and laminin chains. Repair of the basement membrane should therefore be targeted to improve overall lung health.