Boczkowski, J. | Search bioRxiv

bioRxiv2025

Targeting p16INK4a reverses alveolar epithelial cell dysfunction and induces lung regeneration in emphysema

Pulmonary emphysema involves impaired regenerative capacity of alveolar type 2 epithelial cells (AT2), the main progenitor cells in alveoli. However, the mechanisms underlying dysfunctional epithelial repair remain unclear. In a mouse model of elastase-induced emphysema, we observed an accumulation of activated AT2s in the lung, associated with an overexpression of p16INK4a (p16), a cell cycle inhibitor known to influence stem cell fate. Deletion of p16 promoted the transition of AT2 into alveolar type 1 (AT1) cells, resulting in tissue regeneration in both mice and alveolar organoids. Pharmacological targeting of the p16 pathway using senolytic agents recapitulate this regenerative effect, further supporting the role of p16 as a key brake on epithelial plasticity. These findings demonstrate that alveolar epithelial cell dysfunction can be reversed by p16 deletion or by eliminating p16+ cells, thereby reactivating the AT2-to-AT1 transition and promoting endogenous alveolar regeneration. This work identifies the p16 pathway as a promising therapeutic target for restoring damaged alveoli in emphysema.

cell biology↗

bioRxiv2017

Inflammatory Cellular Response To Mechanical Ventilation In Elastase-Induced Experimental Emphysema: Role Of Pre-Existing Alveolar Macrophages Infiltration

BackgroundAn excessive pulmonary inflammatory response could explain the poor prognosis of chronic obstructive pulmonary disease (COPD) patients submitted to invasive mechanical ventilation. The aim of this study was to evaluate the response to normal tidal volume (Vt) mechanical ventilation in a murine model of pulmonary emphysema, which represents the alveolar component of COPD. In this model, two time points associated with different levels of lung inflammation but similar lung destruction, were analyzed.\n\nMethodsC57BL/6 mice received a tracheal instillation of 5 IU of porcine pancreatic elastase (Elastase mice) or the same volume of saline (Saline mice). Fourteen (D14) and 21 (D21) days after instillation, mice were anesthetized, intubated, and either mechanically ventilated (MV) with a normal Vt (8 mL/kg) or maintained on spontaneous ventilation (SV) during two hours. We analyzed respiratory mechanics, emphysema degree (mean chord length by lung histological analysis), and lung inflammation (bronchoalveolar lavage (BAL) cellularity, proportion and activation of total lung inflammatory cells by flow cytometry).\n\nResultsAs compared with Saline mice, Elastase mice showed a similarly increased mean chord length and pulmonary compliance at D14 and D21, while BAL cellularity was comparable between groups. Lung mechanics was similarly altered during mechanical ventilation in Elastase and Saline mice. Activated alveolar macrophages CD11bmid were present in lung parenchyma in both Elastase SV mice and Elastase MV mice at D14 but were absent at D21 and in Saline mice, indicating an inflammatory state with elastase at D14 only. At D14, Elastase MV mice showed a significant increase in percentage of neutrophils concomitant with a decrease in percentage of alveolar macrophages in total lung, as compared with Elastase SV mice. Furthermore, alveolar macrophages of Elastase MV mice at D14 overexpressed Gr1, and monocytes showed a trend to overexpression of CD62L, compared with Elastase SV mice.\n\nConclusionsIn an elastase-induced model of pulmonary emphysema, normal Vt mechanical ventilation produced an increase in the proportion of pulmonary neutrophils, and an activation of alveolar macrophages and pulmonary monocytes. This response was observed only when the emphysema model showed an underlying inflammation (D14), reflected by the presence of activated alveolar macrophages CD11bmid.

cell biology↗