RT Journal Article
SR Electronic
T1 Transcriptome analysis of IPF fibroblastic foci identifies key pathways involved in fibrogenesis
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP thoraxjnl-2020-214902
DO 10.1136/thoraxjnl-2020-214902
A1 Delphine Guillotin
A1 Adam R Taylor
A1 Manuela Platé
A1 Paul F Mercer
A1 Lindsay M Edwards
A1 Ross Haggart
A1 Gino Miele
A1 Robin J McAnulty
A1 Toby M Maher
A1 Robert E Hynds
A1 Mariam Jamal-Hanjani
A1 Richard P Marshall
A1 Andrew J Fisher
A1 Andy D Blanchard
A1 Rachel C Chambers
YR 2020
UL http://thorax.bmj.com/content/early/2020/11/18/thoraxjnl-2020-214902.abstract
AB Introduction Fibroblastic foci represent the cardinal pathogenic lesion in idiopathic pulmonary fibrosis (IPF) and comprise activated fibroblasts and myofibroblasts, the key effector cells responsible for dysregulated extracellular matrix deposition in multiple fibrotic conditions. The aim of this study was to define the major transcriptional programmes involved in fibrogenesis in IPF by profiling unmanipulated myofibroblasts within fibrotic foci in situ by laser capture microdissection.Methods The challenges associated with deriving gene calls from low amounts of RNA and the absence of a meaningful comparator cell type were overcome by adopting novel data mining strategies and by using weighted gene co-expression network analysis (WGCNA), as well as an eigengene-based approach to identify transcriptional signatures, which correlate with fibrillar collagen gene expression.Results WGCNA identified prominent clusters of genes associated with cell cycle, inflammation/differentiation, translation and cytoskeleton/cell adhesion. Collagen eigengene analysis revealed that transforming growth factor β1 (TGF-β1), RhoA kinase and the TSC2/RHEB axis formed major signalling clusters associated with collagen gene expression. Functional studies using CRISPR-Cas9 gene-edited cells demonstrated a key role for the TSC2/RHEB axis in regulating TGF-β1-induced mechanistic target of rapamycin complex 1 activation and collagen I deposition in mesenchymal cells reflecting IPF and other disease settings, including cancer-associated fibroblasts.Conclusion These data provide strong support for the human tissue-based and bioinformatics approaches adopted to identify critical transcriptional nodes associated with the key pathogenic cell responsible for fibrogenesis in situ and further identify the TSC2/RHEB axis as a potential novel target for interfering with excessive matrix deposition in IPF and other fibrotic conditions.