Project description:Lung cancer is closely associated with chronic inflammation, but the mechanism underlying such inflammation has not been clearly defined. The lung is a mucosal tissue colonized by a diverse bacterial community at the steady state, and pulmonary infections commonly present in lung cancer patients are linked to clinical outcomes. Here we provide evidence that local microbiota provoke inflammation associated with lung adenocarcinoma by activating lung-resident gamma-delta T cells. Germ-free or antibiotic-treated mice were significantly protected from lung tumor initiation and progression induced by Kras mutation and p53 loss. Mechanistically, commensal bacteria stimulated My88-dependent IL-1beta and IL-23 production from myeloid cells, inducing proliferation and activation of Vγ6+Vδ1+ γδ T cells that produced IL-17 and other effector molecules to promote inflammation and tumor cell proliferation. Our findings provide a clear link between local microbiota-immune crosstalk and lung tumorigenesis, and thereby define key cellular and molecular mediators that may serve as effective targets in lung cancer treatment and prevention.
Project description:The ocular surface is colonized by commensal microbiota, which tune the local mucosal immune response. However, the mechanisms underlying the induction of an IL-17 response by γδ T cells in response to ocular commensal bacteria, particularly Corynebacterium mastitidis (C. mast), have not been fully investigated. Here, we demonstrated that intrinsic TLR2 activation in γδ T cells by commensal microbiota is required for their IL-17A production and fatty acid oxidation. We also identified IκBζ, a transcription factor whose expression is upregulated by TLR2 signaling, as a key regulator to enhance the expression of genes responsible for IL-17A production and FAO program. This study highlights the role of TLR2-mediated transcriptional regulation in targeting effector cytokines and metabolic programs to support IL-17A responses to commensal bacteria.
Project description:The ocular surface is colonized by commensal microbiota, which tune the local mucosal immune response. However, the mechanisms underlying the induction of an IL-17 response by γδ T cells in response to ocular commensal bacteria, particularly Corynebacterium mastitidis (C. mast), have not been fully investigated. Here, we demonstrated that intrinsic TLR2 activation in γδ T cells by commensal microbiota is required for their IL-17A production and fatty acid oxidation. We also identified IκBζ, a transcription factor whose expression is upregulated by TLR2 signaling, as a key regulator to enhance the expression of genes responsible for IL-17A production and FAO program. This study highlights the role of TLR2-mediated transcriptional regulation in targeting effector cytokines and metabolic programs to support IL-17A responses to commensal bacteria.
Project description:Obesity is detrimental to the immune system. It impairs lymphatics, T cell development, and lymphopoiesis; induces dysfunction of antitumor immunity; and also promotes tumor progression. However, direct evidence of the impact of obesity on viral infection is lacking. We found an unexpected protective role of obesity against herpes simplex virus 2 infection of the genital mucosa in mice. Although conventional antiviral immunity was comparable between obese mice and lean mice, obesity enhanced the cytotoxic subset of γδ T cells. This effect was mediated by L-arginine produced by commensal microbiota in the genital mucosa, which induced “pseudonormoxia” of γδ T cells, resulting in increased NKG2D expression of γδ T cells through the downregulation of HIF1A by inducing NO production, thereby protecting mice from lethal genital herpes. Thus, our work illuminates one mechanism by which obesity-induced compositional changes in the vaginal microbiota can affect mucosal immune responses against viral infection.
Project description:The mammalian gastrointestinal tract harbors thousands of bacterial species that include symbionts as well as potential pathogens. The immune responses that limit access of these bacteria to underlying tissue remain poorly defined. In this study, we used microarrays to uncover the transcriptional responses that occur in small intestinal γδ intraepithelial lymphocytes following bacterial challenge. γδ intraepithelial lymphocytes (γδ IEL) were isolated by flow cytometry from the small intestines of germ-free mice, or from age- and sex-matched conventionally-raised counterparts. We extracted RNAs from these purified γδ IEL for analysis on Affymetrix DNA microarrays. The mice were all >8 weeks in age, and each sample represents a pool of RNAs from 5-8 mice.
Project description:Triple negative breast cancer (TNBC) lacks targeted therapy options. TNBC is enriched in breast cancer stem cells (BCSCs), which play a key role in metastasis, chemoresistance, relapse and mortality. γδ T cells hold great potential in immunotherapy against cancer, and might be an alternative to target TNBC. γδ T cells are commonly observed to infiltrate solid tumors and have an extensive repertoire of tumor sensing, recognizing stress-induced molecules and phosphoantigens (pAgs) on transformed cells. We show that patient derived triple negative BCSCs are efficiently recognized and killed by ex vivo expanded γδ T cells from healthy donors. Orthotopically xenografted BCSCs, however, were refractory to γδ T cell immunotherapy. Mechanistically, we unraveled concerted differentiation and immune escape: xenografted BCSCs lost stemness, expression of γδ T cell ligands, adhesion molecules and pAgs, thereby evading immune recognition by γδ T cells. Indeed, neither pro-migratory engineered γδ T cells, nor anti-PD 1 checkpoint blockade significantly prolonged overall survival of tumor-bearing mice. BCSC immune escape was independent of the immune pressure exerted by the γδ T cells, and could be pharmacologically reverted by Zoledronate or IFN-α treatment. These results pave the way for novel combinatorial immunotherapies for TNBC.
Project description:Tissue physiology and responses to injury can be controlled by the cross-talk between all physiological systems including the nervous and immune system. How the microbiota influences this dialogue remains unclear. Here, we show that adaptive responses to the microbiota directly promote sensory neuron regeneration. At homeostasis, commensal-specific Th17 co-localize with sensory neurons within the dermis and display a transcriptional profile associated with tissue and nerve repair. Following injury, commensal-specific Th17 cells promote axon growth and local nerve regeneration. Mechanistically, our data support the idea that IL17-A produced by commensal-specific T cells directly signal sensory neurons via IL17RA, the transcription of which is specifically upregulated in injured neurons. Collectively our work reveals that microbiota-specific T cells can bridge biological systems by directly promoting neuronal repair and identify IL17-A as a major determinant of this fundamental process.
Project description:Essential to terrestrial life is the formation of a competent skin barrier that prevents desiccation and entry by harmful substances. A tightly orchestrated series of cellular changes is required for the proper formation of the epidermal permeability barrier. These changes occur in the context of the commensal skin microbiota. Using germ free mice and antibiotic depletion models, we demonstrate the microbiota is necessary for proper differentiation and repair of the barrier. These effects were mediated by keratinocyte signaling through the aryl hydrocarbon receptor (AHR), a xenobiotic receptor that also regulates epidermal differentiation. Murine skin lacking keratinocyte AHR was more susceptible to infection by S. aureus and increased pathology in a model of atopic dermatitis. Topical colonization with a defined consortium of human skin commensals restored barrier competence in germ free skin and during epicutaneous sensitization; these effects were dependent on keratinocyte AHR. We reveal a fundamental role for the commensal skin microbiota in directing skin barrier formation and repair through the AHR, with far-reaching implications for the numerous skin disorders characterized by disrupted epidermal differentiation and/or barrier competence.