Critical role for the TGF-β1/mTORC1 signalling axis in defining the transcriptional identity of CTHRC1+ pathologic fibroblasts in idiopathic pulmonary fibrosis

ABSTRACT: Fibroblasts represent key effector cells responsible for fibrogenesis during wound healing and pathological fibrosis, including idiopathic pulmonary fibrosis (IPF), the most rapidly progressive and fatal fibrotic lung disease. Single-cell RNA sequencing of fibrotic lung tissue has identified a novel population of high collagen-producing fibroblasts not present in non-diseased control lung, characterised by high expression of the marker, collagen triple helix repeat containing 1 (CTHRC1). The cardinal pro-fibrotic mediator TGF-β1 has been widely implicated in promoting fibrogenesis in multiple fibrotic conditions. In addition to the canonical Smad signalling pathway, TGF-β1-induced collagen I production is under critical regulatory control by the mTORC1/4E-BP1 signalling hub. Using pharmacological inhibition (dual ATP-competitive mTOR inhibitors and rapamycin) in combination with gene-editing approaches, we now demonstrate that the role of the mTORC1 axis extends to the regulation of over a third of all TGF-β1 regulated matrisome genes. We further show that the global transcriptome of TGF-β1-stimulated fibroblasts matches that of CTHRC1+ pathological fibroblast population in the IPF lung. In contrast, the TGF-β1 induced transcriptome of fibroblasts in which mTORC1-signalling is disrupted (by RPTOR gene editing using CRISPR-Cas9) does not map to any known fibroblast population. These data define, for the first time, a critical role for both TGF-β1 and the mTORC1 signalling hub in determining the transcriptional identity of CTHRC1+ pathological fibroblasts and provide strong scientific support for targeting mTORC1 as a therapeutic strategy in IPF and potentially other fibrotic conditions associated with dysregulated TGF-β1 profibrotic signalling.

ORGANISM(S): Homo sapiens

PROVIDER: GSE272972 | GEO | 2026/07/21

REPOSITORIES: GEO