Dataset Information

Efficacious anti-CTLA-4 antibodies drive myeloid activation and TME reprograming through FcγR engagement and Type-I interferon signaling

ABSTRACT: Despite the clinical success of checkpoints inhibitors, a significant gap still exists in our understanding of their in vivo mechanism of action, thus limiting the rational development of next generation agents. Amongst these, anti-CTLA-4 antibodies were originally developed to block inhibitory signals into activated effector T cells. However, several recent studies have demonstrated that depletion of regulatory T cells expressing high levels of CTLA-4 is critical to anti-CTLA-4 anti-tumor activity. Whereas the mechanism of action remains controversial, the emerging data support clinical development of new antibodies with enhanced killing activity. Here, using single-cell RNA sequencing in in vivo and in vitro mouse models, we sought to dissect the impact of anti-CTLA-4 blocking, Treg depleting, and FcR engaging activity on the immune responses within tumors. We observed a rapid remodeling of the innate immune landscape as early as 24-hours post-treatment. Immune remodeling was driven mainly by FcγR-engagement, and not by Treg depletion or CTLA-4 blockade, and included reduction of suppressive macrophages and activation of type-I interferon signaling. Our findings indicate that FcγR engagement and innate immune remodeling are involved in successful anti-CTLA-4 treatment, supporting further development of optimized immunotherapy agents with these features.

ORGANISM(S): Mus musculus

PROVIDER: GSE186484 | GEO | 2022/08/11

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:Maternal antibodies specific for antigens in the developing brain are implicated as risk factors for neurodevelopmental disorders, but how these antibodies interfere with neurodevelopment remain speculative. It has been postulated that immunoglobulin G-immune complexes (IgG-IC) activate Fc gamma receptors (FcγR) on non-immune cells in the brain, thereby modulating intracellular signaling and/or internalizing function-blocking antibodies specific for intracellular antigens. However, testing this hypothesis has been hindered by the paucity of data regarding FcγR in the developing brain. Thus, we first investigated FcγR expression in the brain of neonatal male and female rats using quantitative PCR analyses. FcgrIa, FcgrIIa, FcgrIIb, FcgrIIIa and Fcgrt transcripts were detectable in the cortex, hippocampus and cerebellum at postnatal days 1 and 7. These transcripts were also present in primary hippocampal and cortical cell cultures, where their expression was upregulated by IFNγ. In order to confirm protein abundance of FcγRIa, FcγRIIb and FcγRIIIa in cultured hippocampal and cortical neurons and astrocytes on the single cell and tissue level we used immunocytochemistry, western blotting, proteotype analysis, and flow cytometry. The data shows that a subpopulation of these cells co-express the excitatory FcγRIa and the inhibitory FcγRIIb. Functional analysis shows that exposure of hippocampal and cortical cell cultures to IgG-IC increased intracellular calcium and Erk phosphorylation, and triggered FcγR-mediated internalization of IgG. Collectively, these data demonstrate that developing neurons and astrocytes express signaling competent FcγR. which could establish a molecular mode of action of maternal antibodies could influence vulnerability to neurodevelopmental disorders via direct interactions with FcγR on non-immune cells in the developing brain. These findings support the hypothesis that maternal antibodies influence vulnerability to neurodevelopmental disorders via direct interactions with FcγR on non-immune cells in the developing brain.

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

Efficacious anti-CTLA-4 antibodies drive myeloid activation and TME reprograming through FcγR engagement and Type-I interferon signaling

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets