TNF-α, PDGF, and TGF-β1 expression by primary mouse bronchiolar-alveolar epithelial and mesenchymal cells: TNF-α induces TGF-β1

G. Sakuntala Warshamana, Miriam Corti, Arnold R. Brody

Research output: Contribution to journalArticle

87 Scopus citations

Abstract

The bronchiolar-alveolar epithelium (BAE) is a primary target site for inhaled agents that cause lung injury. These cells, consequently, release a broad range of mediators that influence other cell populations, including interstitial lung fibroblasts that are central to the development of interstitial pulmonary fibrosis (IPF). A number of peptide growth factors (GF) have been postulated to be essential in the pathogenesis of IPF. We demonstrate here that primary populations of mouse BAE and mesenchymal cells, maintained in culture, synthesize four potent GF. These are platelet-derived growth factor isoforms (PDGF) A and B, transforming growth factor beta-1 (TGF-β1), and tumor necrosis factor alpha (TNF-α). A mouse lung epithelial cell isolation technique pioneered in this laboratory has been used to purify the BAE cells to greater than 85% (80 ± 5.6% alveolar type II and 9 ± 2.3% Clara cells) in culture. Northern analysis, RNase protection assay, and immunocytochemistry (ICC) were used to establish mRNA and protein expression of the GF over time in the cultured BAE and mesenchymal cells. We show for the first time in these primary mouse lung cells that treatment of both cell types with TNF-α upregulates expression of TGF-β1. The four GF are produced by both epithelial and mesenchymal cells but with different temporal patterns. TGF-β1 is expressed constitutively by BAE and mesenchymal cells, whereas TNF-α expression wanes over time. The findings by ICC were consistent with levels of mRNA expression in both cell types. As genetically defined and altered mouse strains are becoming increasingly valuable for modeling lung disease, studying the gene expression patterns of target cells from these animals in vitro would be useful in sorting out the complex responses by individual cell types of the lung and the interactions among the multitude of mediators that are released during lung cell injury.

Original languageEnglish (US)
Pages (from-to)13-33
Number of pages21
JournalExperimental and Molecular Pathology
Volume71
Issue number1
DOIs
StatePublished - 2001
Externally publishedYes

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Keywords

  • Alveolar type II cells
  • Growth factors
  • Immunocytochemistry
  • Northern analysis
  • RNase protection assay

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Pathology and Forensic Medicine

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