Crystalline silica-induced recruitment and immuno-imbalance of CD4 +
Tissue Resident Memory T cells promote the progression of silicosis.
Abstract
Background: Occupational crystalline silica (CS) particle exposure leads
to silicosis. The burden of CS-associated disease remains high, and
treatment options are limited due to vague mechanisms. CD4
+ tissue-resident memory T cells (T
RM) accumulate in the lung responded to CS particles,
mediating the pathogenesis of silicosis. Methods: Based on silicosis
murine model by single intratracheal instillation of CS suspension, we
further employ adoptive transfer, FTY720 treatment, and parabiosis
murine model to explore their source. After defining T
RM cell subsets by CD103 and CD69, we intervene CD103
+subset and block IL-7 signaling to alleviate
silicosis. Results: The CD4 + T RM
cells are derived from peripheral lymphocyte recruitment and in
situ expansion. Specifically, T RM-Treg cells depend
more on circulating T cell replenishment. The cell retention markers
CD103 and CD69 can divide the T RM cells into effector
and regulatory subsets. However, targeting CD103 + T
RM-Treg cells do not mitigate disease phenotype since
the T RM subsets exerted immunosuppressive but not
pro-fibrotic roles. We further dissect that IL-7 signaling promotes the
progression of silicosis by tuning the maintenance of T
RM-effector T cells. Conclusion: Our findings highlight
the distinct role of CD4 + T RM cells
in mediating CS-induced fibrosis and provide potential therapeutic
strategies for silicosis.