10 research outputs found

    d4eBP acts downstream of both dTOR and dFoxo to modulate cardiac functional aging in Drosophila

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75079/1/ACEL_504_sm_FigS1_TableS1-S2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/75079/2/j.1474-9726.2009.00504.x.pd

    Btla signaling in conventional and regulatory lymphocytes coordinately tempers humoral immunity in the intestinal mucosa

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    The Btla inhibitory receptor limits innate and adaptive immune responses, both preventing the development of autoimmune disease and restraining anti-viral and anti-tumor responses. It remains unclear how the functions of Btla in diverse lymphocytes contribute to immunoregulation. Here, we show that Btla inhibits activation of genes regulating metabolism and cytokine signaling, including Il6 and Hif1a, indicating a regulatory role in humoral immunity. Within mucosal Peyer\u27s patches, we find T-cell-expressed Btla-regulated Tfh cells, while Btla in T or B cells regulates GC B cell numbers. Treg-expressed Btla is required for cell-intrinsic Treg homeostasis that subsequently controls GC B cells. Loss of Btla in lymphocytes results in increased IgA bound to intestinal bacteria, correlating with altered microbial homeostasis and elevations in commensal and pathogenic bacteria. Together our studies provide important insights into how Btla functions as a checkpoint in diverse conventional and regulatory lymphocyte subsets to influence systemic immune responses

    Gut microbiota dependent anti-tumor immunity restricts melanoma growth in Rnf5 mice

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    Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5 and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5 mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5 mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth

    Gut microbiota dependent anti-tumor immunity restricts melanoma growth in Rnf5−/− mice

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    Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5−/− and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5−/− mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5−/− mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth

    Highly Complementary Target RNAs Promote Release of Guide RNAs from Human Argonaute2

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    Argonaute proteins use small RNAs to guide the silencing of complementary target RNAs in many eukaryotes. Although small RNA biogenesis pathways are well studied, mechanisms for removal of guide RNAs from Argonaute are poorly understood. Here we show that the Argonaute2 (Ago2) guide RNA complex is extremely stable, with a half-life on the order of days. However, highly complementary target RNAs destabilize the complex and significantly accelerate release of the guide RNA from Ago2. This “unloading” activity can be enhanced by mismatches between the target and the guide 5â€Č end and attenuated by mismatches to the guide 3â€Č end. The introduction of 3â€Č mismatches leads to more potent silencing of abundant mRNAs in mammalian cells. These findings help to explain why the 3â€Č ends of mammalian microRNAs (miRNAs) rarely match their targets, suggest a mechanism for sequence-specific small RNA turnover, and offer insights for controlling small RNAs in mammalian cells
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