Protective responses against pathogens require a rapid mobilization of resting neutrophils and the timely removal of activated ones. Neutrophils are exceptionally short-lived leukocytes, yet it remains unclear whether the lifespan of pathogen-engaged neutrophils is regulated differently from that in the circulating steady-state pool. Here, we have found that under homeostatic conditions, the mRNA-destabilizing protein tristetraprolin (TTP) regulates apoptosis and the numbers of activated infiltrating murine neutrophils but not neutrophil cellularity. Activated TTP-deficient neutrophils exhibited decreased apoptosis and enhanced accumulation at the infection site. In the context of myeloid-specific deletion of
Florian Ebner, Vitaly Sedlyarov, Saren Tasciyan, Masa Ivin, Franz Kratochvill, Nina Gratz, Lukas Kenner, Andreas Villunger, Michael Sixt, Pavel Kovarik
Ajitha Thanabalasuriar, Bas G.J. Surewaard, Michelle E. Willson, Arpan S. Neupane, Charles K. Stover, Paul Warrener, George Wilson, Ashley E. Keller, Bret R. Sellman, Antonio DiGiandomenico, Paul Kubes
A large proportion of human T cells are autoreactive to group 1 CD1 proteins, which include CD1a, CD1b, and CD1c. However, the physiological role of the CD1 proteins remains poorly defined. Here, we have generated a double-transgenic mouse model that expresses human CD1b and CD1c molecules (hCD1Tg) as well as a CD1b-autoreactive TCR (HJ1Tg) in the ApoE-deficient background (hCD1Tg HJ1Tg
Sreya Bagchi, Ying He, Hong Zhang, Liang Cao, Ildiko Van Rhijn, D. Branch Moody, Johann E. Gudjonsson, Chyung-Ru Wang
Inflammatory bowel disease (IBD) is characterized by dysregulation in both cytokines and responses to intestinal microbes, and proper regulation of pattern recognition receptor (PRR) signaling is critical for intestinal immune homeostasis. Altered functions for the IBD risk locus containing rs7554511, which encompasses the
Jie Yan, Matija Hedl, Clara Abraham
Tissue-resident immune cells play a key role in local and systemic immune responses. The liver, in particular, hosts a large number of invariant natural killer T (iNKT) cells, which are involved in diverse immune responses. However, the mechanisms that regulate survival and homeostasis of liver iNKT cells are poorly defined. Here we have found that liver iNKT cells constitutively express the costimulatory TNF superfamily receptor OX40 and that OX40 stimulation results in massive pyroptotic death of iNKT cells, characterized by the release of potent proinflammatory cytokines that induce liver injury. This OX40/NKT pyroptosis pathway also plays a key role in concanavalin A–induced murine hepatitis. Mechanistically, we demonstrated that liver iNKT cells express high levels of caspase 1 and that OX40 stimulation activates caspase 1 via TNF receptor–associated factor 6–mediated recruitment of the paracaspase MALT1. We also found that activation of caspase 1 in iNKT cells results in processing of pro–IL-1β to mature IL-1β as well as cleavage of the pyroptotic protein gasdermin D, which generates a membrane pore–forming fragment to produce pyroptotic cell death. Thus, our study has identified OX40 as a death receptor for iNKT cells and uncovered a molecular mechanism of pyroptotic cell death. These findings may have important clinical implications in the development of OX40-directed therapies.
Peixiang Lan, Yihui Fan, Yue Zhao, Xiaohua Lou, Howard P. Monsour, Xiaolong Zhang, Yongwon Choi, Yaling Dou, Naoto Ishii, Rafik M. Ghobrial, Xiang Xiao, Xian Chang Li
Proinflammatory cytokine overproduction and excessive cell death, coupled with impaired clearance of apoptotic cells, have been implicated as causes of failure to resolve gut inflammation in inflammatory bowel diseases. Here we have found that dendritic cells expressing the apoptotic cell–recognizing receptor CD300f play a crucial role in regulating gut inflammatory responses in a murine model of colonic inflammation. CD300f-deficient mice failed to resolve dextran sulfate sodium–induced colonic inflammation as a result of defects in dendritic cell function that were associated with abnormal accumulation of apoptotic cells in the gut. CD300f-deficient dendritic cells displayed hyperactive phagocytosis of apoptotic cells, which stimulated excessive TNF-α secretion predominantly from dendritic cells. This, in turn, induced secondary IFN-γ overproduction by colonic T cells, leading to prolonged gut inflammation. Our data highlight a previously unappreciated role for dendritic cells in controlling gut homeostasis and show that CD300f-dependent regulation of apoptotic cell uptake is essential for suppressing overactive dendritic cell–mediated inflammatory responses, thereby controlling the development of chronic gut inflammation.
Ha-Na Lee, Linjie Tian, Nicolas Bouladoux, Jacquice Davis, Mariam Quinones, Yasmine Belkaid, John E. Coligan, Konrad Krzewski
Inborn errors of DNA repair or replication underlie a variety of clinical phenotypes. We studied 5 patients from 4 kindreds, all of whom displayed intrauterine growth retardation, chronic neutropenia, and NK cell deficiency. Four of the 5 patients also had postnatal growth retardation. The association of neutropenia and NK cell deficiency, which is unusual among primary immunodeficiencies and bone marrow failures, was due to a blockade in the bone marrow and was mildly symptomatic. We discovered compound heterozygous rare mutations in Go-Ichi-Ni-San (GINS) complex subunit 1 (
Julien Cottineau, Molly C. Kottemann, Francis P. Lach, Young-Hoon Kang, Frédéric Vély, Elissa K. Deenick, Tomi Lazarov, Laure Gineau, Yi Wang, Andrea Farina, Marie Chansel, Lazaro Lorenzo, Christelle Piperoglou, Cindy S. Ma, Patrick Nitschke, Aziz Belkadi, Yuval Itan, Bertrand Boisson, Fabienne Jabot-Hanin, Capucine Picard, Jacinta Bustamante, Céline Eidenschenk, Soraya Boucherit, Nathalie Aladjidi, Didier Lacombe, Pascal Barat, Waseem Qasim, Jane A. Hurst, Andrew J. Pollard, Holm H. Uhlig, Claire Fieschi, Jean Michon, Vladimir P. Bermudez, Laurent Abel, Jean-Pierre de Villartay, Frédéric Geissmann, Stuart G. Tangye, Jerard Hurwitz, Eric Vivier, Jean-Laurent Casanova, Agata Smogorzewska, Emmanuelle Jouanguy
Programmed death ligand-1 (PD-L1) interacts with programmed death-1 (PD-1) and the immunostimulatory molecule CD80 and functions as a checkpoint to regulate immune responses. The interaction of PD-L1 with CD80 alone has been shown to exacerbate the severity of graft-versus-host disease (GVHD), whereas costimulation of CD80 and PD-1 ameliorates GVHD. Here we have demonstrated that temporary depletion of donor CD4+ T cells early after hematopoietic cell transplantation effectively prevents GVHD while preserving strong graft-versus-leukemia (GVL) effects in allogeneic and xenogeneic murine GVHD models. Depletion of donor CD4+ T cells increased serum IFN-γ but reduced IL-2 concentrations, leading to upregulation of PD-L1 expression by recipient tissues and donor CD8+ T cells. In GVHD target tissues, the interactions of PD-L1 with PD-1 on donor CD8+ T cells cause anergy, exhaustion, and apoptosis, thereby preventing GVHD. In lymphoid tissues, the interactions of PD-L1 with CD80 augment CD8+ T cell expansion without increasing anergy, exhaustion, or apoptosis, resulting in strong GVL effects. These results indicate that the outcome of PD-L1–mediated signaling in CD8+ T cells depends on the presence or absence of CD4+ T cells, the nature of the interacting receptor expressed by CD8+ T cells, and the tissue environment in which the signaling occurs.
Xiong Ni, Qingxiao Song, Kaniel Cassady, Ruishu Deng, Hua Jin, Mingfeng Zhang, Haidong Dong, Stephen Forman, Paul J. Martin, Yuan-Zhong Chen, Jianmin Wang, Defu Zeng
The growth factor receptor Kit is involved in hematopoietic and nonhematopoietic development. Mice bearing
Pierre Cunin, Loka R. Penke, Jonathan N. Thon, Paul A. Monach, Tatiana Jones, Margaret H. Chang, Mary M. Chen, Imene Melki, Steve Lacroix, Yoichiro Iwakura, Jerry Ware, Michael F. Gurish, Joseph E. Italiano, Eric Boilard, Peter A. Nigrovic
Acute graft-versus-host disease (aGVHD) is the most common complication for patients undergoing allogeneic stem cell transplantation. Despite extremely aggressive therapy targeting donor T cells, patients with grade III or greater aGVHD of the lower GI tract, who do not respond to therapy with corticosteroids, have a dismal prognosis. Thus, efforts to improve understanding of the function of local immune and non-immune cells in regulating the inflammatory process in the GI tract during aGVHD are needed. Here, we demonstrate, using murine models of allogeneic BMT, that type 2 innate lymphoid cells (ILC2s) in the lower GI tract are sensitive to conditioning therapy and show very limited ability to repopulate from donor bone marrow. Infusion of donor ILC2s was effective in reducing the lethality of aGVHD and in treating lower GI tract disease. ILC2 infusion was associated with reduced donor proinflammatory Th1 and Th17 cells, accumulation of donor myeloid-derived suppressor cells (MDSCs) mediated by ILC2 production of IL-13, improved GI tract barrier function, and a preserved graft-versus-leukemia (GVL) response. Collectively, these findings suggest that infusion of donor ILC2s to restore gastrointestinal tract homeostasis may improve treatment of severe lower GI tract aGVHD.
Danny W. Bruce, Heather E. Stefanski, Benjamin G. Vincent, Trisha A. Dant, Shannon Reisdorf, Hemamalini Bommiasamy, David A. Serody, Justin E. Wilson, Karen P. McKinnon, Warren D. Shlomchik, Paul M. Armistead, Jenny P.Y. Ting, John T. Woosley, Bruce R. Blazar, Dietmar M.W. Zaiss, Andrew N.J. McKenzie, James M. Coghill, Jonathan S. Serody