Project description:Innate immune cells shape the host response to microbial pathogens. Here we studied the role of TLR7/9 in dendritic cell (DC) responses to Histoplasma capsulatum, an intracellular fungal pathogen of humans. Whereas macrophages succumbed to Histoplasma infection, TLR7/9 were critical for DCs to produce Type I interferons (IFN-I), restrict fungal growth, and survive fungal infection. In the mouse model of infection, optimal IFN-I and IFN gamma production, host survival, and restriction of cerebral fungal burden were also dependent on TLR7/9. Interestingly, CD103+ conventional DCs were the major producer of IFN-I in the lungs of infected mice, revealing a previously unknown role for these cells and uncovering their pivotal function in modulating the host immune response to endemic fungi.
Project description:Innate immune cells shape the host response to microbial pathogens. Here we studied the role of TLR7/9 in dendritic cell (DC) responses to Histoplasma capsulatum, an intracellular fungal pathogen of humans. Whereas macrophages succumbed to Histoplasma infection, TLR7/9 were critical for DCs to produce Type I interferons (IFN-I), restrict fungal growth, and survive fungal infection. In the mouse model of infection, optimal IFN-I and IFN gamma production, host survival, and restriction of cerebral fungal burden were also dependent on TLR7/9. Interestingly, CD103+ conventional DCs were the major producer of IFN-I in the lungs of infected mice, revealing a previously unknown role for these cells and uncovering their pivotal function in modulating the host immune response to endemic fungi. In 6-well tissue culture treated dishes, 1 x 10 6 BMDCs or BMMs were subjected to either mock infection, infection with UV-treated Histoplasma, or infection with live Histoplasma yeasts at an MOI of 4. UV-treated (UVT) yeasts were prepared by subjecting G217B to UV light (UV Stratalinker 1800) for 1 hour; these yeasts failed to generate colonies when plated on HMM agarose.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of genes differentially expressed between WT, Batf3 KO and Notch2 KO colons following C. rodentium infection. Mice were infected with 2 x 10^9 C. rodentium and colons harvested at either Day 4 or Day 9.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of differentially expressed genes in ESAM+ and ESAM- CD11b+ and DEC205+ splenic classical DC subsets. Splenocytes were harvested from WT C57Bl/6 or WT Cx3cr1-gfp mice and cDC subsets sorted to >95% purity on the FACSAriaII.
Project description:Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of Notch2-dependent genes in CD11b+ and DEC205+ splenic classical DC subsets. Splenocytes were harvested from littermate WT Notch2 f/f C57Bl/6 or Notch2 CD11c-cre C57Bl/6 mice and DC subsets sorted to >95% purity on the FACSAriaII.
Project description:Epstein-Barr virus (EBV) causes endemic Burkitt lymphoma and immunosuppression-related lymphomas. These B-cell malignancies arise by distinct transformation pathways and utilize divergent viral and host expression programs. To identify host dependency factors elicited by EBV latent-infection states, we performed parallel genome-wide CRISPR/Cas9 screens in Burkitt lymphoma (BL) and lymphoblasotid cell lines (LCL). Our results highlighted 57 BL and 87 LCL genes selectively critical for their growth and survival. LCL hits were enriched for EBV-induced genes, including viral super-enhancer targets and multiple kinases. We uncovered key CD19/CD81 roles in EBV membrane protein-driven PI3K/AKT activation and mechanisms by which EBV evades tumor suppressor responses to its growth program. LMP1-induced cFLIP was critical for LCL defense against TNFa-mediated programmed cell death, while EBV-induced BATF/IRF4 were critical for LCL BIM suppression and MYC induction. EBV super-enhancer targeted IRF2 protected LCLs against BLIMP1 responses. Collectively, our results identify host/pathogen interaction-driven synthetic lethal targets for therapeutic intervention.
Project description:Successful host defense against pathogens requires innate immune recognition of the correct pathogen associated molecular patterns (PAMPs) by pathogen recognition receptors (PRRs) to trigger the appropriate gene program tailored to the pathogen. While many PRR pathways have been shown to contribute to the innate immune response to specific pathogens, the relative importance of each pathway for the complete transcriptional program elicited has not been examined in detail. Herein, we used RNA-sequencing with wildtype and mutant macrophages to delineate the innate immune pathways responsible for the early transcriptional response to Staphylococcus aureus, a ubiquitous microorganism that can activate a wide variety of PRRs. Unexpectedly, only two PRR pathways – the Toll-like receptor (TLR) and Stimulator of Interferon Gene (STING) pathways - were identified as dominant regulators of approximately 95% of the genes that were potently induced within the first four hours of macrophage infection with live S. aureus. TLR signaling predominantly activated an inflammatory program, STING signaling activated an antiviral/type I interferon response, and both pathways contributed to a program linking innate and adaptive immunity. Only a small number of genes were induced in the absence of TLR or STING signaling, and these genes possessed a strong hypoxia signature. STING pathway activation required live S. aureus and was largely dependent on the DNA sensor cyclic guanosine-adenosine synthase (cGAS) recognition of S. aureus DNA. Interestingly, using a cutaneous infection model, we found that the TLR and STING pathways played opposite roles in host defense to S. aureus, with TLR signaling being required for protective interleukin (IL)-1 and neutrophil recruitment and STING signaling having an opposite effect. These results provide novel insights into the complex interplay of innate immune signaling pathways triggered byS. aureus and uncover opposing roles of TLR and STING in cutaneous host defense to S. aureus.