Dysregulated lung stroma drives emphysema exacerbation by potentiating resident lymphocytes to suppress an epithelial stem cell reservoir

C Wang, B Hyams, NC Allen, K Cautivo, K Monahan… - Immunity, 2023 - cell.com
C Wang, B Hyams, NC Allen, K Cautivo, K Monahan, M Zhou, MW Dahlgren, CO Lizama…
Immunity, 2023cell.com
Aberrant tissue-immune interactions are the hallmark of diverse chronic lung diseases.
Here, we sought to define these interactions in emphysema, a progressive disease
characterized by infectious exacerbations and loss of alveolar epithelium. Single-cell
analysis of human emphysema lungs revealed the expansion of tissue-resident lymphocytes
(TRLs). Murine studies identified a stromal niche for TRLs that expresses Hhip, a disease-
variant gene downregulated in emphysema. Stromal-specific deletion of Hhip induced the …
Summary
Aberrant tissue-immune interactions are the hallmark of diverse chronic lung diseases. Here, we sought to define these interactions in emphysema, a progressive disease characterized by infectious exacerbations and loss of alveolar epithelium. Single-cell analysis of human emphysema lungs revealed the expansion of tissue-resident lymphocytes (TRLs). Murine studies identified a stromal niche for TRLs that expresses Hhip, a disease-variant gene downregulated in emphysema. Stromal-specific deletion of Hhip induced the topographic expansion of TRLs in the lung that was mediated by a hyperactive hedgehog-IL-7 axis. 3D immune-stem cell organoids and animal models of viral exacerbations demonstrated that expanded TRLs suppressed alveolar stem cell growth through interferon gamma (IFNγ). Finally, we uncovered an IFNγ-sensitive subset of human alveolar stem cells that was preferentially lost in emphysema. Thus, we delineate a stromal-lymphocyte-epithelial stem cell axis in the lung that is modified by a disease-variant gene and confers host susceptibility to emphysema.
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