Inhibition of LTβR-signalling activates Wnt-induced regeneration in lung

Lymphotoxin β-receptor (LTβR)-signalling orchestrates lymphoid neogenesis and subsequent tertiary lymphoid structures (TLS)(1,2), associated with severe chronic inflammatory diseases spanning multiple organ systems(3–6). How LTβR-signalling drives chronic tissue damage particularly in the lung, which mechanism(s) regulate this process, and whether LTβR-blockade might be of therapeutic value has remained unclear. Here we demonstrate increased expression of LTβR-ligands on adaptive and innate immune-cells, enhanced non-canonical NF-κB signalling and enriched LTβR-target gene expression in epithelial cells of lungs from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and mice exposed to chronic cigarette smoke. Therapeutic inhibition of LTβR-signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue (iBALT), induced lung tissue regeneration, and reverted airway-fibrosis and systemic muscle wasting. Mechanistically, LTβR-signalling blockade dampened epithelial non-canonical NF-κB activation, reduced TGFβ-signalling in airways, induced regeneration by preventing epithelial cell-death and by activating Wnt/β-catenin-signalling in alveolar epithelial progenitor cells. These findings highlight that LTβR-signalling inhibition represents a viable therapeutic option combining anti-TLS, anti-apoptotic with tissue regenerative strategies.