IMR Press / FBL / Volume 29 / Issue 8 / DOI: 10.31083/j.fbl2908305
Open Access Short Communication
Investigation of Aberrant Basaloid Cells in a Rat Model of Lung Fibrosis
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Affiliation
1 Department of Neuroscience, Psychology, Drug Area and Child Health, University of Florence, 50139 Florence, Italy
2 Target Innovation Department, Global Research and Preclinical Development, Chiesi Farmaceutici S.p.A., 43122 Parma, Italy
3 Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
*Correspondence: emanuela.bocchi@unifi.it (Emanuela Bocchi); f.ruscitti@chiesi.com (Francesca Ruscitti)
Front. Biosci. (Landmark Ed) 2024, 29(8), 305; https://doi.org/10.31083/j.fbl2908305
Submitted: 8 May 2024 | Revised: 19 July 2024 | Accepted: 31 July 2024 | Published: 22 August 2024
Copyright: © 2024 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease (ILD) whose cause and pathogenesis are not yet well understood. Until now, no animal model of lung fibrosis succeeds in recapitulating all IPF features, thus the use of different rodent models is essential for the evaluation and development of new effective pharmacological treatments. Recently, the alveolar epithelial dysfunction has been emphasized in the etiopathogenesis context of IPF. Remarkably, the role of an aberrant basaloid cell type, primarily found in humans and confirmed in mice, seems to be crucial in the establishment and progression of the disease/model. Our work aimed to characterize for the first time this cell population in a rat model of lung fibrosis induced by a double bleomycin (BLM) administration, demonstrating the translational value of the model and its potential use in the testing of effective new drugs. Methods: Rats received an intratracheal BLM administration at day 0 and 4. Animals were sacrificed 21 and 28 days post-BLM. The fibrosis evaluation was carried out through histological (Ashcroft score and automatic image analysis) and immunoenzymatic analysis. Immunofluorescence was used for the characterization of the aberrant basaloid cells markers. Results: Lung histology revealed an increase in severe grades of Ashcroft scores and areas of fibrosis, resulting in a rise of collagen deposition at both the analyzed time-points. Immunofluorescence staining indicated the presence of KRT8+ cells in bronchial epithelial cells from both controls (saline, SAL) and BLM-treated animals. Interesting, KRT8+ cells were found exclusively in the fibrotic parenchyma (confirmed by the alpha-smooth muscle actin (α-SMA) staining for myofibroblasts) of BLM-treated animals. Moreover, KRT8+ cells co-expressed markers as Prosurfactant protein C (Pro-SPC) and Vimentin, suggesting their intermediate state potentially originating from alveolar type II (AT2) cells, and participating to the abnormal epithelial–mesenchymal crosstalk. Conclusion: Previous preclinical studies demonstrated the presence of KRT8+ aberrant basaloid-like cells in murine models of lung fibrosis. This work investigated the same cell population in a different rodent (the rat) model of lung fibrosis triggered by a double administration of BLM. Our results provided a further confirmation that, in rats, the intratracheal administration of BLM induced the appearance of a population of cells compatible with the KRT8+ alveolar differentiation intermediate (ADI) cells, as described previously in the mouse. This piece of work enforces previous evidence and further support the use of a rat model of BLM resembling the alveolar epithelial dysfunction to evaluate new clinical candidates for development in IPF.

Keywords
idiopathic pulmonary fibrosis
IPF
aberrant basaloid cells
fibroblastic foci
progressive pulmonary fibrosis
KRT8+ epithelial cells
bronchiolization
bleomycin
Funding
Chiesi Farmaceutici S.p.A
Figures
Fig. 1.
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