Biology subjects

Raulet, D.

Publications and source records attributed to Raulet, D..

5 recordsLinked to original sources

bioRxiv2025

Intra-Tumoral Treg Ablation Unleashes NK Cell-Mediated Control of CD8 T Cell-Resistant Tumors

Cancer cells frequently lose MHC I to evade CD8+ T cell recognition. While Natural Killer (NK) cells are poised to target MHC I-deficient cancer cells, MHC I loss alone is often insufficient to unleash fully effective NK cell responses. Here we show that selective intra-tumoral (IT) ablation of regulatory T (Treg) cells elicited potent antitumor NK cell responses that controlled MHC I-deficient and even MHC I+ cancers. Tregs controlled the activation, maturation, and anti-tumor cytotoxic activity of NK cells within the tumor microenvironment. Mechanistically, IT Tregs prevented the cDC2-dependent induction of IL-2 production by CD4+ Tconv cells that was necessary for NK cell activation. Systemically administered antibodies that selectively depleted IT Tregs similarly empowered NK- dependent tumor control. These findings expand the breadth of Treg-mediated cancer immunosuppression to encompass antitumor NK cells and suggest that targeting Tregs in tumors can control CD8+ T cell-resistant cancers. One Sentence SummaryIT Treg ablation drives NK cell tumor control via CD4+ Tconv-derived IL-2, eliminating MHC I+/MHC I- cancers without systemic toxicity.

immunology↗

bioRxiv2024

UFMylation suppresses Type I IFN signaling during M. tuberculosis infection of human macrophages

Type I Interferons (IFN-I) promote host defense against a wide range of viral infections, but inhibit control of several bacterial pathogens, including Mycobacterium tuberculosis (Mtb). Given the significance of IFN-I signaling in determining Mtb infection outcomes, we sought to uncover new molecular mechanisms that regulate IFN-I during mycobacterial infection, specifically focusing on how IFN-I signaling is regulated at the earliest stages of mycobacterial infection as modeled by macrophage infection. To comprehensively identify these host genes, we performed a reporter-based, genome- wide CRISPR-interference screen in human macrophages infected with Mycobacterium marinum, a close relative of Mtb. Our screen detected 2035 significantly enriched genes (p<0.05), which included many known regulators of IFN-I, but also many unexpected genes as potentially novel regulators of IFN-I signaling. One of these unexpected genes was UFL1, an E3-like ligase that catalyzes conjugation of the ubiquitin-like protein, UFM1, in a process termed UFMylation. UFL1-deficiency during Mtb macrophage infection resulted in increased expression of IFN-{beta}, interferon-stimulated genes, and other pro-inflammatory genes, such as TNF and IL-6, at both the transcript and protein level. Depletion of other UFMylation components phenocopied UFL1-deficiency, suggesting that UFMylation activity is required for IFN-I repression. Full transcriptional profiling revealed a broad increase in the inflammatory response of UFL1-deficient cells during Mtb infection, including both protective inflammatory cytokines and potentially detrimental interferon-stimulated genes. Our results suggest a role for UFMylation in suppressing IFN-I signaling and inflammatory responses during the earliest stages of Mtb infection. IMPORTANCEMycobacterium tuberculosis was estimated to have caused over 1 million deaths in 2025 - the most deaths globally by a single bacterial pathogen. Past studies in mice and humans have shown that some host immune responses, such as IFN-I signaling, can enhance susceptibility to M. tuberculosis. We report the results of our genome-wide CRISPR-interference screen to determine regulators of IFN-I signaling during the earliest stages of mycobacterial infection. This screen identified new regulators of IFN-I signaling, including the UFMylation pathway, which appears to play an unexpected role in suppressing both IFN-I signaling and a broader inflammatory response. These findings may be relevant for the development of therapeutics and prophylactics for tuberculosis that impact IFN-I signaling - a known determinant of tuberculosis susceptibility.

microbiology↗

bioRxiv2022

Induced CD45 Proximity Potentiates Natural Killer Cell Receptor Antagonism

Natural Killer (NK) cells are a major subset of innate immune cells that are essential for host defense against pathogens and cancer. Two main classes of inhibitory NK receptors (NKR), KIR and CD94/NKG2A, play a key role in suppressing NK activity upon engagement with tumor cells or virus infected cells, limiting their antitumor and antiviral activity. Here, we find that single-chain mouse NKR antagonists linked to a VHH that binds the cell surface phosphatase CD45 potentiate NK and T activity to a greater extent than NKR blocking antibodies alone in vitro. We also uncovered crosstalk between mouse NKG2A and Ly49 that collectively inhibit NK cell activation, such that CD45-NKG2A and CD45-Ly49 bispecific molecules show synergistic effects in their ability to enhance NK cell activation. The basis of the activity enhancement by CD45 ligation may reflect greater antagonism of inhibitory signaling from engagement of MHC I on target cells, combined with other mechanisms, including avidity effects, tonic signaling, antagonism of weak inhibition from engagement of MHC I on non-target cells and possibly CD45 segregation within the NK cell-target cell synapse. These engineered ligands uncover a mechanism for enhancing the activity of mouse NK and T cells that merits evaluation in the context of human NKR antagonist cancer immunotherapies.

bioengineering↗

bioRxiv2021

Binary outcomes of enhancer activity underlie stable random monoallelic expression

Mitotically stable random monoallelic gene expression (RME) is documented for a small percentage of autosomal genes. Here we investigated the role of enhancers in the RME of natural killer (NK) cell receptor genes. Enhancers were accessible and enriched in H3K27ac on silent and active alleles alike, decoupling enhancer activation and expression. Enhancers controlled gene expression frequency, as predicted by the binary model of enhancer action, and enhancer deletion converted the broadly expressed Nkg2d into an RME gene, recapitulating natural variegation. The results suggested that RME is a consequence of general enhancer properties and therefore many genes may be subject to some degree of RME, which was borne out by analysis of a panel of genes previously thought to be universally expressed within defined hematopoietic lineages: Nkg2d, Cd45, Cd8a and Thy1. We propose that previously documented RME is an extreme on a continuum of intrinsically probabilistic gene expression.

molecular biology↗

bioRxiv2019

SLC19A1 is a cyclic dinucleotide transporter

The accumulation of DNA in the cytosol serves as a key immunostimulatory signal associated with infections, cancer and genomic damage1,2. Cytosolic DNA triggers immune responses by activating the cGAS/STING pathway3. The binding of DNA to the cytosolic enzyme cGAMP synthase (cGAS), activates its enzymatic activity, leading to the synthesis of a second messenger, cyclic[G(2,5)pA(3,5)] (23-cGAMP)4-8. 23-cGAMP, a cyclic dinucleotide (CDN), activates the protein stimulator of interferon genes (STING)9, which in turn activates the transcription factors IRF3 and NF-{kappa}B promoting the transcription of genes encoding type I interferons and other cytokines and mediators that stimulate a broader immune response. Exogenous 23-cGAMP and other CDNs, including CDNs produced by bacteria and synthetic CDNs used in cancer immunotherapy, must traverse the cell membrane to activate STING in target cells. How these charged CDNs pass through the lipid bilayer is unknown. Here we used a genome-wide CRISPR interference screen to identify the reduced folate carrier SLC19A1 as the major CDN transporter for uptake of synthetic and naturally occurring CDNs. CDN uptake and functional responses are inhibited by depleting SLC19A1 from cells and enhanced by overexpressing SLC19A1. In both cell lines and primary cells ex vivo, CDN uptake is inhibited competitively by folate and blocked by the SLC19A1 inhibitor sulfasalazine, a medication approved for the treatment of inflammatory diseases. The identification of SLC19A1 as the major transporter of CDNs into cells has far reaching implications for the immunotherapeutic treatment of cancer10, transport of 23-cGAMP from tumor cells to other immune cells to trigger the anti-tumor immune response11, host responsiveness to CDN-producing pathogenic microorganisms12, and potentially in certain inflammatory diseases.

immunology↗