Chronic signaling via the metabolic checkpoint kinase mTORC1 induces macrophage granuloma formation and marks sarcoidosis progression
Ontology highlight
ABSTRACT: Gene expression analysis of primary CSF1-deprived bone marrow-derived macrophages (BMDM) of Tsc2fl/fl LysM+/+ and TSC2fl/fl LysM+/cre mice Maintenance of tissue homeostasis requires a tight control of the in situ-proliferative capacity of tissue-resident macrophages. Here we show that specific deletion of Tsc2 in myeloid cells breaks quiescence and strongly induces macrophage proliferation and hypertrophy leading to granuloma formation in vivo in an mTORC1-dependent manner. Intriguingly, the growth factor CSF1 induces expression of cyclin-dependent kinase 4 (CDK4) via TSC2-mTORC1 to stimulate cell proliferation, while simultaneously NF-κB signaling and apoptosis are inhibited. Tsc2-deficient macrophages show constitutive CDK4 expression and enhanced M2-like polarization that is supported by a metabolic reprogramming towards increased glycolysis and mitochondrial metabolism. Strikingly, mTORC1 activation and macrophage proliferation are identified as a hallmark of the human granulomatous disease sarcoidosis and correlate with a clinically progressive disease outcome. In conclusion, TSC2-mTORC1 integrates macrophage quiescence, polarization, and metabolism to prevent granulomatous disease. Fundamentally, we show that the macrophage cell cycle is controlled by a growth factor-induced expression of CDK4.
ORGANISM(S): Mus musculus
PROVIDER: GSE77075 | GEO | 2017/01/03
SECONDARY ACCESSION(S): PRJNA309394
REPOSITORIES: GEO
ACCESS DATA