Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19

Area of Science:

• Pulmonology
• Immunology
• Pathology

Background:

• Post-Acute Sequelae of COVID-19 (PASC) presents significant long-term health challenges, with unclear mechanisms behind persistent inflammation and poor organ recovery.
• Respiratory PASC, characterized by abnormal lung function and pulmonary fibrosis, requires further investigation into its underlying pathophysiology.

Approach:

• Developed a mouse model of post-viral lung sequelae mirroring human PASC, utilizing spatial transcriptomics and imaging.
• Analyzed clinical cohorts of PASC patients with pulmonary complications to validate findings.

Key Points:

• Identified unique immune cell-epithelial progenitor interactions driving fibroproliferation in respiratory PASC.
• Discovered that lung-resident CD8+ T cell-macrophage interactions maintain abnormal progenitor cells, hindering alveolar regeneration.
• Elucidated a mechanism where CD8+ T cell-derived IFN-γ and TNF induce chronic IL-1β release from macrophages, promoting fibrosis.

Conclusions:

• Dysregulated immune-epithelial progenitor niche drives respiratory PASC.
• Therapeutic neutralization of IFN-γ, TNF, or IL-1β post-infection can improve alveolar regeneration and lung function.
• Highlighted potential late-stage therapeutic strategies for post-viral fibrotic disease.