What does this research mean for the field?

Cellular senescence during healthy lung aging contributes to significant alterations in the extracellular matrix proteome through autocrine and paracrine signaling. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This research investigates how senescence affects the extracellular matrix in aging lungs.

May 20, 2026

C29-11 Senescence in Healthy Lung Aging Contributes to Changes in the Extracellular Matrix Proteome

Key Points

This research investigates how senescence affects the extracellular matrix in aging lungs.
Utilized 20 healthy human lung tissues (ages 4 months to 90 years) for LC-MS/MS analysis.
Prepared immunohistochemistry slides for tissue evaluation and ex vivo models using PCLS.
Induced senescence using bleomycin and assessed via mRNA, protein levels, and staining.
Identified 15 key ECM proteins significantly altered with age, including S100A9 and COL12A1.
Confirmed senescence markers in fibroblasts and PCLS through mRNA and staining.
Further treatment showed recombinant S100A9 increased senescence and ECM protein expression.

Abstract

Abstract Rationale Aging is characterized by several hallmarks, including senescence, which has been implicated in chronic lung diseases. Senescence is a stress-induced mechanism leading to permanent cell cycle arrest and increased release of cytokines and chemokines. Previous studies have focused largely on cellular outcomes of senescence, however, effects on the extracellular matrix (ECM) altered upon lung aging and injury, remain elusive. We aim to decipher changes in the ECM proteome in the aging lung and investigate whether and how trigger- and cell-specific senescence is sufficient to drive ECM changes. Methods Twenty healthy human donor lung tissues were obtained (4mo-90yrs) for label-free liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis completed in the Schilling Lab. Immunohistochemistry slides were prepared with human cohort tissue embedded in paraffin. Fibroblasts and precision cut lung slices (PCLS), an ex vivo model for multicellular interactions and ECM in the native lung, were prepared from human lung tissue into 300um thick and 1cm diameter slices. Samples were treated with bleomycin (15ug/mL) to induce senescence. Results LC-MS/MS was performed on 20 human donor lung tissues ranging from 4 months to 90 years old, to identify a list of proteins differentially expressed with age. Statistical analysis revealed significant changes in abundance and expression of proteins, with the largest group representing ECM proteins, identified through the MatrisomeDB. To further investigate whether these changes are mediated by cellular senescence, we analyzed senescent fibroblasts and PCLS. Senescence was confirmed by assessing p21/p16 mRNA and protein levels, and β-galactosidase staining. We identified 15 key ECM proteins that were significantly altered in both lists, including S100A9, FBLN1, NID1 and COL12A1. Localization of key proteins was identified through immunohistochemistry slides of the aging cohort. These proteins were associated with activated fibroblasts (Pdgfra/aSMA), alveolar type 2 epithelial cells (Sftpc/HTII-280), and infiltrating immune cell populations (CD68/CD177). Further treatment of epithelial cells and fibroblasts with recombinant S100A9 resulted in increased senescence and ECM expression, including identified proteins NID1 and FBLN1. Conclusion The lung ECM is significantly altered over the lifespan. Autocrine and paracrine signaling of senescent cells contributing to ECM alterations. This abstract is funded by: NIA U54 AG075931

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