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GATA2 restricts genomic actions of innate immune mediators on fetal hematopoietic progenitor cells

ABSTRACT: Innate immune signaling protects against pathogens, controls hematopoietic development and functions in oncogenesis, yet the relationship between these mechanisms is incompletely defined. Downregulating the GATA2 transcription factor in fetal hematopoietic progenitor cells upregulates genes encoding innate immune regulators, increases Interferon-g (IFNg) signaling and disrupts differentiation. Here, we demonstrate that deletion of an enhancer that confers GATA2 expression in fetal progenitor cells elevated Toll-Like Receptor (TLR) TLR1/2 and TLR2/6 expression and signaling. Genetic rescue by expressing GATA2 downregulated the elevated TLR signaling. IFNg amplified TLR1/2 and TLR2/6 signaling in GATA2-deficient progenitor cells, synergistically activating cytokine/chemokine genes and elevating cytokine/chemokine production in their myeloid cell progeny. Genome-wide analysis of how IFNg and TLR signaling remodels the progenitor cell transcriptome in GATA2-deficient cells revealed exaggerated responses at innate immune genes harboring motifs for signal-dependent transcription factors. Thus, GATA2 establishes a transcriptome that constrains innate immune signaling, and insufficient GATA2 renders fetal progenitor cells hypersensitive to innate immune signaling.

ORGANISM(S): Mus musculus

PROVIDER: GSE218445 | GEO | 2023/04/15

REPOSITORIES: GEO

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Project description:The activation of TLR-MyD88 (Toll like receptor- Myeloid differentiation factor 88) signaling within T cells functions as a potent costimulatory signal that boosts antitumor and antiviral responses. However, the molecular mechanisms underlying the costimulatory processes are poorly understood. We compared microarray gene analysis data between TLR1-TLR2 stimulated and unstimulated T cell receptor transgenic âpmelâ and MyD88-/-pmel CD8+ T cells and identified changes in the expression levels of several TNF family members. In particular, TLR-stimulation increased 4-1BB levels in pmel but not in MyD88-/-pmel T cells. A link between 4-1BB and TLR1-TLR2 signaling in CD8+ T cells was highlighted by in fact that 4-1BB-/- T cells exhibited suboptimal responses to TLR1-TLR2 agonist, but responded normally to CD28 or OX40 costimulation. Moreover, blocking 4-1BB signaling with antibodies also hindered the costimulatory effects of the TLR1-TLR2 agonist. The elevated levels of 4-1BB transcripts in TLR1-TLR2âstimulated cells were not due to increased mRNA stability nor increased histone activation but instead were associated with increased binding of p65 and c-Jun to two distinct 4-1BB promoter sites. Combining TLR1-TLR2 ligand with an agonistic anti-4-1BB antibody enhanced the antitumor activity in mice with established melanoma tumors. These studies reveal that the costimulatory effects of TLR1-TLR2 signaling in CD8+ T cells are in part mediated by 4-1BB and are important for mounting an effective antitumor immune response. CD8+ T cells from the B6.Cg-Thy1/Cy Tg(TcraTcrb)8Rest/J mice, referred to as âpmelâ T cells or from MyD88 knockout pmel mice (MyD88â/âpmel) were sorted. pmel and MyD88â/âpmel T cells were activated using MyD88â/â CD8 T cell-depleted splenocytes pulsed with 10ng/ml of mgp100. This was with or without 10Âµg/ml of Pam3CSK4. pmel or MyD88â/âpmel CD8 T cells were enriched and used for the extraction of RNA used for genomic analysis.

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GATA2 restricts genomic actions of innate immune mediators on fetal hematopoietic progenitor cells

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