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Updated: Jul 21, 2025

Single-channel Analysis and Calcium Imaging in the Podocytes of the Freshly Isolated Glomeruli
Published on: June 27, 2015
PAI-1 regulates AT2-mediated re-alveolarization and ion permeability
Gibran Ali1, Mo Zhang1,2, Jianjun Chang1
1Department of Cellular and Molecular Biology, Texas Lung Injury Institute, University of Texas at Tyler Health Science Center, Tyler, TX, USA.
Elevated plasminogen activator inhibitor-1 (PAI-1) in injured lungs impairs alveolar epithelial regeneration. This is due to reduced self-renewal of alveolar type 2 (AT2) cells, especially CD44+ cells, hindering lung repair.
Area of Science:
- Pulmonary Medicine
- Regenerative Medicine
- Cell Biology
Background:
- Acute lung injury (ALI) is marked by high levels of plasminogen activator inhibitor-1 (PAI-1) in lung fluid and circulation.
- The specific role of PAI-1, encoded by the Serpine1 gene, in the repair of injured lung epithelium remains unclear.
Purpose of the Study:
- To investigate the function of Serpine1 in regulating the fate of alveolar type 2 (AT2) cells.
- To analyze AT2 cell behavior in a humanized mouse model with mutated Serpine1 (Serpine1Tg).
Main Methods:
- Cultured wild-type (wt) and Serpine1Tg AT2 cells as monolayers and 3D alveolospheres.
- Assessed colony formation and organoid surface area.
- Quantified AT1 and AT2 cells using immunohistochemistry and FACS, and analyzed epithelial barrier properties.
Main Results:
- Serpine1Tg AT2 cells showed significantly reduced self-renewal and colony formation compared to wt controls.
- Organoids derived from Serpine1Tg AT2 cells exhibited decreased surface area, indicating impaired re-epithelialization.
- FACS analysis revealed fewer AT2 cells, particularly CD44+ cells, and an altered AT1:AT2 cell ratio in Serpine1Tg organoids.
Conclusions:
- Elevated PAI-1 in injured lungs negatively impacts alveolar epithelial regeneration.
- This downregulation is mediated by reduced AT2 cell self-renewal, especially affecting the CD44+ subpopulation.
- Findings highlight PAI-1 as a critical factor in limiting lung epithelial repair.
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