Dataset Information

A lineage of myelolymphoblastic innate cells unmasked by inactivation of mTOR complex 1

ABSTRACT: Blockades in hematopoiesis deprive the host of vital blood cells and frequently cause leukemia. Here we show that inactivation of mTORC1 in hematopoietic stem cells by deletion of Raptor unmasked a cell type, hereby called myelolymphoblastic innate cell (MLIC) based on unique gene expression signature, cell surface markers, morphology and functions. The MLICs are CD11b(+)Gr-1(-)B7-H1(high)F4/80(low) and have morphology of lymphoblasts with active Ig loci but no gene rearrangement. Within weeks of Raptor deletion, the MLICs account for nearly 50% of bone marrow cells and are found throughout both the lymphoid and non-lymphoid organs. Nevertheless, the MLICs are not malignant as they undergo very limited proliferation in vivo. Importantly, the MLICs broadly express pattern-recognition receptors and produce large amounts of inflammatory cytokines in response to all TLR ligands tested, rendering the host highly susceptible to pathogen-associated molecular patterns. Our data suggest that hematopoietic cell-intrinsic mTORC1 prevents development of self-destructive innate immune attack by suppressing generation of MLICs.

ORGANISM(S): Mus musculus

PROVIDER: GSE67863 | GEO | 2017/12/05

SECONDARY ACCESSION(S): PRJNA281089

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:The mechanistic target of rapamycin (mTOR) pathway integrates diverse environmental inputs, including immune signals and metabolic cues, to direct T cell fate decisions1. Activation of mTOR, comprised of mTORC1 and mTORC2 complexes, delivers an obligatory signal for proper activation and differentiation of effector CD4+ T cells2,3, whereas in the regulatory T cell (Treg) compartment, the Akt-mTOR axis is widely acknowledged as a crucial negative regulator of Treg de novo differentiation4-8 and population expansion9. However, whether mTOR signaling affects the homeostasis and function of Tregs remains largely unexplored. Here we show that mTORC1 signaling is a pivotal positive determinant of Treg function. Tregs have elevated steady-state mTORC1 activity compared to naïve T cells. Signals via T cell receptor (TCR) and IL-2 provide major inputs for mTORC1 activation, which in turn programs suppressive function of Tregs. Disruption of mTORC1 through Treg-specific deletion of the essential component Raptor leads to a profound loss of Treg suppressive activity in vivo and development of a fatal early-onset inflammatory disorder. Mechanistically, Raptor/mTORC1 signaling in Tregs promotes cholesterol/lipid metabolism, with the mevalonate pathway particularly important for coordinating Treg proliferation and upregulation of suppressive molecules CTLA-4 and ICOS to establish Treg functional competency. In contrast, mTORC1 does not directly impact the expression of Foxp3 or anti- and pro-inflammatory cytokines in Tregs, suggesting a non-conventional mechanism for Treg functional regulation. Lastly, we provide evidence that mTORC1 maintains Treg function partly through inhibiting the mTORC2 pathway. Our results demonstrate that mTORC1 acts as a fundamental ‘rheostat’ in Tregs to link immunological signals from TCR and IL-2 to lipogenic pathways and functional fitness, and highlight a central role of metabolic programming of Treg suppressive activity in immune homeostasis and tolerance. We used microarrays to explore the gene expression profiles differentially expressed in regulatory T-cells from wild-type and CD4(cre) x Raptor(fl/fl) mice

Dataset Information

A lineage of myelolymphoblastic innate cells unmasked by inactivation of mTOR complex 1

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure