Unbiased Quantitation of Alveolar Type II to Alveolar Type I Cell Transdifferentiation during Repair after Lung Injury in Mice
| Autor: | Jazalle McClendon, Rubin M. Tuder, Nicole L. Jansing, Peter M. Henson, Dallas M. Hyde, Rachel L. Zemans |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Pulmonary and Respiratory Medicine Pathology medicine.medical_specialty transdifferentiation Cells 1.1 Normal biological development and functioning Alveolar Epithelium alveolar epithelium Respiratory System Clinical Biochemistry Mice Transgenic Cardiorespiratory Medicine and Haematology Biology Lung injury Stem cell marker Transgenic Epithelium Green fluorescent protein Mice 03 medical and health sciences lung injury and repair 0302 clinical medicine Underpinning research In vivo medicine 2.1 Biological and endogenous factors Animals Aetiology Lung Molecular Biology Cells Cultured Cell Proliferation Cultured Alveolar type Transdifferentiation Lung Injury Cell Biology respiratory system Cell biology Pulmonary Alveoli Major Technical Advances 030104 developmental biology Alveolar Epithelial Cells 030220 oncology & carcinogenesis Cell Transdifferentiation Respiratory |
| Zdroj: | American journal of respiratory cell and molecular biology, vol 57, iss 5 |
| ISSN: | 1535-4989 1044-1549 |
| Popis: | The alveolar epithelium consists of squamous alveolar type (AT) I and cuboidal ATII cells. ATI cells cover 95-98% of the alveolar surface, thereby playing a critical role in barrier integrity, and are extremely thin, thus permitting efficient gas exchange. During lung injury, ATI cells die, resulting in increased epithelial permeability. ATII cells re-epithelialize the alveolar surface via proliferation and transdifferentiation into ATI cells. Transdifferentiation is characterized by down-regulation of ATII cell markers, up-regulation of ATI cell markers, and cell spreading, resulting in a change in morphology from cuboidal to squamous, thus restoring normal alveolar architecture and function. The mechanisms underlying ATII to ATI cell transdifferentiation have not been well studied in vivo. A prerequisite for mechanistic investigation is a rigorous, unbiased method to quantitate this process. Here, we used SPCCreERT2;mTmG mice, in which ATII cells and their progeny express green fluorescent protein (GFP), and applied stereologic techniques to measure transdifferentiation during repair after injury induced by LPS. Transdifferentiation was quantitated as the percent of alveolar surface area covered by ATII-derived (GFP+) cells expressing ATI, but not ATII, cell markers. Using this methodology, the time course and magnitude of transdifferentiation during repair was determined. We found that ATI cell loss and epithelial permeability occurred by Day 4, and ATII to ATI cell transdifferentiation began by Day 7 and continued until Day 16. Notably, transdifferentiation and barrier restoration are temporally correlated. This methodology can be applied to investigate the molecular mechanisms underlying transdifferentiation, ultimately revealing novel therapeutic targets to accelerate repair after lung injury. |
| Databáze: | OpenAIRE |
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