Xuhong Cheng

University of Texas MD Anderson Cancer Center, Houston, TX, United States

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Publications (10)187.57 Total impact

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    ABSTRACT: Production of type I interferons (IFN-I) is a crucial innate immune mechanism against viral infections. IFN-I induction is subject to negative regulation by both viral and cellular factors, but the underlying mechanism remains unclear. We report that the noncanonical NF-κB pathway was stimulated along with innate immune cell differentiation and viral infections and had a vital role in negatively regulating IFN-I induction. Genetic deficiencies in major components of the noncanonical NF-κB pathway caused IFN-I hyperinduction and rendered cells and mice substantially more resistant to viral infection. Noncanonical NF-κB suppressed signal-induced histone modifications at the Ifnb promoter, an action that involved attenuated recruitment of the transcription factor RelA and a histone demethylase, JMJD2A. These findings reveal an unexpected function of the noncanonical NF-κB pathway and highlight an important mechanism regulating antiviral innate immunity.
    Immunity 03/2014; 40(3):342-54. · 19.80 Impact Factor
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    ABSTRACT: Microglia are crucial for the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Here we show that the E3 ubiquitin ligase Peli1 is abundantly expressed in microglia and promotes microglial activation during the course of EAE induction. Peli1 mediates the induction of chemokines and proinflammatory cytokines in microglia and thereby promotes recruitment of T cells into the central nervous system. The severity of EAE is reduced in Peli1-deficient mice despite their competent induction of inflammatory T cells in the peripheral lymphoid organs. Notably, Peli1 regulates Toll-like receptor (TLR) pathway signaling by promoting degradation of TNF receptor-associated factor 3 (Traf3), a potent inhibitor of mitogen-activated protein kinase (MAPK) activation and gene induction. Ablation of Traf3 restores microglial activation and CNS inflammation after the induction of EAE in Peli1-deficient mice. These findings establish Peli1 as a microglia-specific mediator of autoimmune neuroinflammation and suggest a previously unknown signaling mechanism of Peli1 function.
    Nature medicine 04/2013; · 27.14 Impact Factor
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    ABSTRACT: The non-canonical NF-κB pathway forms a major arm of NF-κB signalling that mediates important biological functions, including lymphoid organogenesis, B-lymphocyte function, and cell growth and survival. Activation of the non-canonical NF-κB pathway involves degradation of an inhibitory protein, TNF receptor-associated factor 3 (TRAF3), but how this signalling event is controlled is still unknown. Here we have identified the deubiquitinase OTUD7B as a pivotal regulator of the non-canonical NF-κB pathway. OTUD7B deficiency in mice has no appreciable effect on canonical NF-κB activation but causes hyperactivation of non-canonical NF-κB. In response to non-canonical NF-κB stimuli, OTUD7B binds and deubiquitinates TRAF3, thereby inhibiting TRAF3 proteolysis and preventing aberrant non-canonical NF-κB activation. Consequently, the OTUD7B deficiency results in B-cell hyper-responsiveness to antigens, lymphoid follicular hyperplasia in the intestinal mucosa, and elevated host-defence ability against an intestinal bacterial pathogen, Citrobacter rodentium. These findings establish OTUD7B as a crucial regulator of signal-induced non-canonical NF-κB activation and indicate a mechanism of immune regulation that involves OTUD7B-mediated deubiquitination and stabilization of TRAF3.
    Nature 01/2013; · 38.60 Impact Factor
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    ABSTRACT: Immunoglobulin class switching is crucial for the generation of antibody diversity in humoral immunity and, when deregulated, also has severe pathological consequences. How the magnitude of immunoglobulin isotype switching is controlled is still poorly understood. Here we identify the kinase TBK1 as a pivotal negative regulator of class switching to the immunoglobulin A (IgA) isotype. B cell-specific ablation of TBK1 in mice resulted in uncontrolled production of IgA and the development of nephropathy-like disease signs. TBK1 negatively regulated IgA class switching by attenuating noncanonical signaling via the transcription factor NF-κB, an action that involved TBK1-mediated phosphorylation and subsequent degradation of the NF-κB-inducing kinase NIK. Our findings establish TBK1 as a pivotal negative regulator of the noncanonical NF-κB pathway and identify a unique mechanism that controls IgA production.
    Nature Immunology 09/2012; 13(11):1101-9. · 26.20 Impact Factor
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    ABSTRACT: The maintenance of immune homeostasis requires regulatory T cells (Treg cells). Here we found that Treg cell–specific ablation of Ubc13, a Lys63 (K63)-specific ubiquitin-conjugating enzyme, caused aberrant T cell activation and autoimmunity. Although Ubc13 deficiency did not affect the survival of Treg cells or expression of the transcription factor Foxp3, it impaired the in vivo suppressive function of Treg cells and rendered them sensitive to the acquisition of T helper type 1 (TH1) cell– and interleukin 17 (IL-17)-producing helper T (TH17) cell–like effector phenotypes. This function of Ubc13 involved its downstream target, the kinase IKK. The Ubc13-IKK signaling axis controlled the expression of specific Treg cell effector molecules, including IL-10 and SOCS1. Collectively, our findings suggest that the Ubc13-IKK signaling axis regulates the molecular program that maintains Treg cell function and prevents Treg cells from acquiring inflammatory phenotypes.
    Nature Immunology 04/2012; 13(5):481-90. · 26.20 Impact Factor
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    ABSTRACT: T cell activation is subject to tight regulation to avoid inappropriate responses to self antigens. Here we show that genetic deficiency in the ubiquitin ligase Peli1 caused hyperactivation of T cells and rendered T cells refractory to suppression by regulatory T cells and transforming growth factor-β (TGF-β). As a result, Peli1-deficient mice spontaneously developed autoimmunity characterized by multiorgan inflammation and autoantibody production. Peli1 deficiency resulted in the nuclear accumulation of c-Rel, a member of the NF-κB family of transcription factors with pivotal roles in T cell activation. Peli1 negatively regulated c-Rel by mediating its Lys48 (K48) ubiquitination. Our results identify Peli1 as a critical factor in the maintenance of peripheral T cell tolerance and demonstrate a previously unknown mechanism of c-Rel regulation.
    Nature Immunology 08/2011; 12(10):1002-9. · 26.20 Impact Factor
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    ABSTRACT: Follicular helper T (Tfh) cells have a central role in mediating humoral immune responses. Generation of Tfh cells depends on both T-cell intrinsic factors and the supporting function of B cells, but the underlying molecular mechanisms are incompletely understood. Here we show that NF-κB-inducing kinase (NIK), a central component of the noncanonical NF-κB signaling pathway, is required for Tfh cell development. Unlike other known Tfh regulators, NIK acts by controlling the supporting function of B cells. NIK and its upstream BAFF receptor regulate B-cell expression of inducible costimulator ligand (ICOSL), a molecule required for Tfh cell generation. Consistently, injection of a recombinant ICOSL protein into NIK-deficient mice largely rescues their defect in Tfh cell development. We provide biochemical and genetic evidence indicating that the ICOSL gene is a specific target of the noncanonical NF-κB. Our findings suggest that the noncanonical NF-κB pathway regulates the development of Tfh cells by mediating ICOSL gene expression in B cells.
    Proceedings of the National Academy of Sciences 08/2011; 108(31):12827-32. · 9.74 Impact Factor
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    ABSTRACT: T cell receptor-stimulated NF-kappaB activation requires CARMA1 and is negatively regulated by the deubiquitinase CYLD. Recent studies suggest that CARMA1 regulates regulatory T cell (Treg) development, although the role of NF-kappaB in this event is incompletely understood. We show that CYLD deficiency causes constitutive NF-kappaB activation in thymocytes, which is associated with enhanced frequency of Treg cells. The NF-kappaB activation in CYLD-deficient thymocytes is independent of CARMA1, because the NF-kappaB activation was also detected in CYLD/CARMA1 double knock-out thymocytes. Interestingly, although loss of CYLD causes NF-kappaB activation in the CARMA1-deficient thymocytes, the CYLD deficiency fails to rescue the defect of CARMA1 knock-out mice in Treg development. Furthermore, inhibition of canonical NF-kappaB by an IkappaBalpha transgene only partially inhibits Treg development. We demonstrate that CARMA1 regulates IL-2 receptor signaling and controls the IL-2-stimulated maturation of Treg precursors to mature Tregs. These results suggest that the role of CARMA1 in Treg regulation involves both NF-kappaB activation and IL-2 receptor signaling.
    Journal of Biological Chemistry 03/2010; 285(21):15696-703. · 4.65 Impact Factor
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    ABSTRACT: Th17 cells play an important role in mediating autoimmune diseases, but the molecular mechanism underlying Th17 differentiation is incompletely understood. We show here that NF-kappaB-inducing kinase (NIK), which is known to regulate B-cell maturation and lymphoid organogenesis, is important for the induction of Th17 cells. NIK-deficient naive CD4 T cells are attenuated in the differentiation to Th17 cells, although they are competent in committing to the other effector lineages. Consistently, NIK knockout mice are resistant to experimental autoimmune encephalomyelitis, a disease model that involves the function of Th17 cells. This phenotype was also detected in Rag2 knockout mice reconstituted with NIK-deficient T cells, confirming a T-cell intrinsic defect. We further show that NIK mediates synergistic activation of STAT3 by T-cell receptor and IL-6 receptor signals. NIK deficiency attenuates activation of STAT3 and induction of STAT3 target genes involved in Th17-commitment program. These findings establish NIK as an important signaling factor that regulates Th17 differentiation and experimental autoimmune encephalitis induction.
    Blood 06/2009; 113(26):6603-10. · 9.06 Impact Factor