A model of the aged lung epithelium in idiopathic pulmonary fibrosis

Chronic injury of alveolar lung epithelium leads to epithelial disintegrity in idiopathic pulmonary fibrosis (IPF). We had reported earlier that Grhl2, a transcriptional factor, maintains alveolar epithelial cell integrity by directly regulating components of adherens and tight junctions and thus hypothesized an important role of GRHL2 in pathogenesis of IPF. Comparison of GRHL2 distribution at different stages of human lung development showed its abundance in developing lung epithelium and in adult lung epithelium. However, GRHL2 is detected in normal human lung mesenchyme only at early fetal stage (week 9). Similar mesenchymal reexpression of GRHL2 was also observed in IPF. Immunofluorescence analysis in serial sections from three IPF patients revealed at least two subsets of alveolar epithelial cells (AEC), based on differential GRHL2 expression and the converse fluorescence intensities for epithelial vs. mesenchymal markers. Grhl2 was not detected in mesenchyme in intraperitoneal bleomycin-induced injury as well as in spontaneously occurring fibrosis in double-mutant HPS1 and HPS2 mice, whereas in contrast in a radiation-induced fibrosis model, with forced Forkhead box M1 (Foxm1) expression, an overlap of Grhl2 with a mesenchymal marker was observed in fibrotic regions. Grhl2's role in alveolar epithelial cell plasticity was confirmed by altered Grhl2 gene expression analysis in IPF and further validated by in vitro manipulation of its expression in alveolar epithelial cell lines. Our findings reveal important pathophysiological differences between human IPF and specific mouse models of fibrosis and support a crucial role of GRHL2 in epithelial activation in lung fibrosis and perhaps also in epithelial plasticity.

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Network-based identification genetic effect of SARS-CoV-2 infections to Idiopathic pulmonary fibrosis (IPF) patients

Briefings in Bioinformatics ◽

10.1093/bib/bbaa235 ◽

2020 ◽

Cited By ~ 2

Author(s):

Tasnimul Alam Taz ◽

Kawsar Ahmed ◽

Bikash Kumar Paul ◽

Md Kawsar ◽

Nargis Aktar ◽

...

Keyword(s):

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Protein Interactions ◽

Drug Targets ◽

Genetic Effect ◽

Protein Protein Interactions ◽

Lung Epithelium ◽

Drug Molecules ◽

Lung Injuries

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is accountable for the cause of coronavirus disease (COVID-19) that causes a major threat to humanity. As the spread of the virus is probably getting out of control on every day, the epidemic is now crossing the most dreadful phase. Idiopathic pulmonary fibrosis (IPF) is a risk factor for COVID-19 as patients with long-term lung injuries are more likely to suffer in the severity of the infection. Transcriptomic analyses of SARS-CoV-2 infection and IPF patients in lung epithelium cell datasets were selected to identify the synergistic effect of SARS-CoV-2 to IPF patients. Common genes were identified to find shared pathways and drug targets for IPF patients with COVID-19 infections. Using several enterprising Bioinformatics tools, protein–protein interactions (PPIs) network was designed. Hub genes and essential modules were detected based on the PPIs network. TF-genes and miRNA interaction with common differentially expressed genes and the activity of TFs are also identified. Functional analysis was performed using gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway and found some shared associations that may cause the increased mortality of IPF patients for the SARS-CoV-2 infections. Drug molecules for the IPF were also suggested for the SARS-CoV-2 infections.

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