Biology subjects

Irizarry-Caro, R. A.

Publications and source records attributed to Irizarry-Caro, R. A..

2 recordsLinked to original sources

bioRxiv2018

T cells instruct dendritic cells to produce inflammasome independent IL-1β causing systemic inflammation

While IL-1{beta} is critical for anti-microbial host defense, it is also a key mediator of autoimmune inflammation. Inflammasome activation following pathogenic insults is known to result in IL-1{beta} production. However, the molecular events that produce IL-1{beta} during T cell driven autoimmune diseases remain unclear. Here, we have discovered an inflammasome-independent pathway of IL-1{beta} production that is triggered upon cognate interactions between dendritic cells and effector CD4 T cells. Analogous to inflammasome activation, this \"T cell-instructed IL-1{beta} also relies on two independent signaling events. TNF produced by activated CD4 T cells engages TNFR signaling on DCs leading to pro-IL-1{beta} synthesis. Subsequently, FasL, also expressed by effector CD4 T cells, engages Fas on DCs leading to caspase-8 dependent pro-IL-1{beta} cleavage. Remarkably, this two-step mechanism is completely independent of pattern recognition receptor activation. IL-1{beta} produced upon cognate DC-effector CD4 T cell interaction causes wide spread leukocyte infiltration, a hallmark of systemic inflammation as well as autoimmune pathology. This study has uncovered a novel feature of DC-T cell cross-talk that allows for active IL-1{beta} secretion independent of innate sensing pathways and provides a mechanistic explanation for IL-1{beta} production and its downstream consequences in CD4 T cell driven autoimmune pathology.

immunology↗

bioRxiv2018

Transcriptome profiling of pathogen-specific CD4 T cells identifies T-cell-intrinsic caspase-1 as an important regulator of Th17 differentiation

One sentence summaryOur study revealed that DCs shape distinct pathogen-specific CD4 T cell transcriptome and from which, we discovered an unexpected role for T-cell-intrinsic caspase-1 in promoting Th17 differentiation.\n\nABSTRACTDendritic cells (DCs) are critical for priming and differentiation of pathogen-specific CD4 T cells. However, to what extent innate cues from DCs dictate transcriptional changes in T cells leading to effector heterogeneity remains elusive. Here we have used an in vitro approach to prime naive CD4 T cells by DCs stimulated with distinct pathogens. We have found that such pathogen-primed CD4 T cells express unique transcriptional profiles dictated by the nature of the priming pathogen. In contrast to cytokine-polarized Th17 cells that display signatures of terminal differentiation, pathogen-primed Th17 cells maintain a high degree of heterogeneity and plasticity. Further analysis identified caspase-1 as one of the genes upregulated only in pathogen-primed Th17 cells but not in cytokine-polarized Th17 cells. T-cell-intrinsic caspase-1, independent of its function in inflammasome, is critical for inducing optimal pathogen-driven Th17 responses. More importantly, T cells lacking caspase-1 fail to induce colitis following transfer into RAG-deficient mice, further demonstrating the importance of caspase-1 for the development of pathogenic Th17 cells in vivo. This study underlines the importance of DC-mediated priming in identifying novel regulators of T cell differentiation.

immunology↗