Effect of mTORC1 and 2 inhibition on myofibroblast global gene expression 

ABSTRACT: Background: Mechanistic target of rapamycin (mTOR) is a nodal serine/threonine protein kinase critical for the control of fundamental cellular processes. Dysregulated mTOR signalling has been shown in cancer, COPD and idiopathic pulmonary fibrosis (IPF). mTOR forms the catalytic subunit of 2 protein complexes: mTORC1 and mTORC2 which differ in upstream inputs, downstream effects and sensitivity to the allosteric inhibitor rapamycin. Aim: To compare the effects of the mTORC1 inhibitor rapamycin with an ATP-competitive inhibitor of mTORC1/2, AZD8055, on TGFβ1 induced transcriptional responses during myofibroblast differentiation by RNA-Seq analysis. Methods: Primary human lung fibroblasts were treated with TGFβ1 for 24h to induce myofibroblast differentiation and extra cellular matrix (ECM) production in the presence of rapamycin or AZD8055. Fibroblasts were also treated with rapamycin or AZD8055 without TGFβ1. Total mRNA was analysed by RNA-Seq. Results: On a global transcriptomic level, TGFβ1 significantly affected the expression of ~4,200 genes by more than 1.5 fold, of which ~1,100 changes were reversed by pan-mTORC1/2 inhibition, while being insensitive to rapamycin. Only 15 gene changes were reversed exclusively by rapamycin. Analysis of the rapamycin-insensitive, mTOR sensitive myofibroblast transcriptome revealed ECM-receptor interaction, metabolism and actin cytoskeleton regulation as major affected pathways. Conclusions: Our data support the conclusion that therapeutic approaches aimed at interfering with TGFb1 induced myofibroblast differentiation and ECM production require dual mTOR1/2 inhibition and may, in part, explain the lack of clinical efficacy of everolimus in the context of IPF.

ORGANISM(S): Homo sapiens

PROVIDER: GSE102674 | GEO | 2019/05/01

REPOSITORIES: GEO