参考文献

T helper 17 (Th17) cells are pathogenic in many inflammatory diseases,but also support the integrity of the intestinal barrier in a non-inflammatory manner. It is unclear what distinguishes inflammatory Th17 cells elicited by pathogens and tissue-resident homeostatic Th17 cells elicited by commensals. Here,we compared the characteristics of Th17 cells differentiating in response to commensal bacteria (SFB) to those differentiating in response to a pathogen (Citrobacter rodentium). Homeostatic Th17 cells exhibited little plasticity towards expression of inflammatory cytokines,were characterized by a metabolism typical of quiescent or memory T cells,and did not participate in inflammatory processes. In contrast,infection-induced Th17 cells showed extensive plasticity towards pro-inflammatory cytokines,disseminated widely into the periphery,and engaged aerobic glycolysis in addition to oxidative phosphorylation typical for inflammatory effector cells. These findings will help ensure that future therapies directed against inflammatory Th17 cells do not inadvertently damage the resident gut population. View Publication

Extracellular cold-inducible RNA-binding protein (CIRP) exaggerates inflammation and tissue injury in sepsis. Neutrophil extracellular traps (NETs) are released by activated neutrophils during sepsis. NETs contribute to pathogen clearance,but excessive NET formation (NETosis) causes inflammation and tissue damage. Peptidylarginine deiminase 4 (PAD4) is associated with NETosis by increasing histone citrullination and chromatin decondensation. We hypothesized that CIRP induces NETosis in the lungs during sepsis via upregulating PAD4 expression. Sepsis was induced in C57BL/6 wild-type (WT) and CIRP-/- mice by cecal ligation and puncture (CLP). After 20 h of CLP induction,NETs in the lungs of WT and CIRP-/- mice were quantified by flow cytometry by staining the single cell suspensions with MPO and CitH3 Abs. PAD4 expression in the lungs of WT and CIRP-/- mice after sepsis was assessed by Western blotting. In vitro effects of recombinant mouse (rm) CIRP for NETosis and PAD4 expression in the bone marrow-derived neutrophils (BMDN) were assessed by flow cytometry and Western blotting,respectively. After 20 h of CLP,NETosis in the lungs was significantly decreased in CIRP-/- mice compared to WT mice,which also correlated with the decreased PAD4 expression. Intratracheal administration of rmCIRP into WT mice significantly increased NETosis and PAD4 expression in the lungs compared to vehicle-injected mice. In vitro culture of BMDN with rmCIRP significantly increased NETosis and PAD4 expression compared to PBS-treated control. Fluorescence microscopy revealed typical web-like structures consistent with NETs in rmCIRP-treated BMDN. Thus,CIRP serves as a novel inducer of NETosis via PAD4 during sepsis. View Publication

Soybeans are a rich source of isoflavones that have been linked with anti-inflammatory processes and various health benefits. However,specific mechanisms whereby soy bioactives impact immune cell subsets are unclear. Isoflavones,such as genistein and daidzein,are metabolized by microbes to bioactive metabolites as O-desmethylangolensin (O-DMA) and equol,whose presence has been linked to health benefits. We examined how soy isoflavones and metabolites impact natural killer (NK) cell signaling and function. We observe no impact of isoflavones on viability of healthy donor peripheral blood mononuclear cells (PBMCs) or NK cells,even at high (25 µM) concentrations. However,pre-treatment of PBMCs with physiologically-relevant concentrations of genistein (p = 0.0023) and equol (p = 0.006) decreases interleukin (IL)-12/IL-18-induced interferon-gamma (IFN-gamma) production versus controls. Detailed cellular analyses indicate genistein and equol decrease IL-12/IL-18-induced IFN-gamma production by human NK cell subsets,but do not consistently alter cytotoxicity. At the level of signal transduction,genistein decreases IL-12/IL-18-induced total phosphorylated tyrosine,and phosphorylation MAPK pathway components. Further,genistein limits IL-12/IL-18-mediated upregulation of IL-18Ralpha expression on NK cells (p = 0.0109). Finally,in vivo studies revealed that C57BL/6 mice fed a soy-enriched diet produce less plasma IFN-gamma following administration of IL-12/IL-18 versus control-fed animals (p {\textless} 0.0001). This study provides insight into how dietary soy modulates NK cell functions. View Publication

Exposure to Mycobacterium tuberculosis (Mtb) results in heterogeneous clinical outcomes including primary progressive tuberculosis and latent Mtb infection (LTBI). Mtb infection is identified using the tuberculin skin test and interferon-gamma (IFN-gamma) release assay IGRA,and a positive result may prompt chemoprophylaxis to prevent progression to tuberculosis. In the present study,we report on a cohort of Ugandan individuals who were household contacts of patients with TB. These individuals were highly exposed to Mtb but tested negative disease by IFN-gamma release assay and tuberculin skin test,'resisting' development of classic LTBI. We show that 'resisters' possess IgM,class-switched IgG antibody responses and non-IFN-gamma T cell responses to the Mtb-specific proteins ESAT6 and CFP10,immunologic evidence of exposure to Mtb. Compared to subjects with classic LTBI,'resisters' display enhanced antibody avidity and distinct Mtb-specific IgG Fc profiles. These data reveal a distinctive adaptive immune profile among Mtb-exposed subjects,supporting an expanded definition of the host response to Mtb exposure,with implications for public health and the design of clinical trials. View Publication

BACKGROUND Cytotoxic T lymphocyte antigen-4 (CTLA-4) limits T-cell activation and is expressed on T-regulatory cells. Human CTLA-4 deficiency results in severe immune dysregulation. Abatacept (CTLA-4 Ig) is approved for the treatment of rheumatoid arthritis (RA) and its mechanism of action is attributed to effects on T-cells. It is known that CTLA-4 modulates the expression of its ligands CD80 and CD86 on antigen presenting cells (APC) by transendocytosis. As B-cells express CD80/CD86 and function as APC,we hypothesize that B-cells are a direct target of abatacept. OBJECTIVES To investigate direct effects of abatacept on human B-lymphocytes in vitro and in RA patients. METHODS The effect of abatacept on healthy donor B-cells' phenotype,activation and CD80/CD86 expression was studied in vitro. Nine abatacept-treated RA patients were studied. Seven of these were followed up to 24 months,and two up to 12 months only and treatment response,immunoglobulins,ACPA,RF concentrations,B-cell phenotype and ACPA-specific switched memory B-cell frequency were assessed. RESULTS B-cell development was unaffected by abatacept. Abatacept treatment resulted in a dose-dependent decrease of CD80/CD86 expression on B-cells in vitro,which was due to dynamin-dependent internalization. RA patients treated with abatacept showed a progressive decrease in plasmablasts and serum IgG. While ACPA-titers only moderately declined,the frequency of ACPA-specific switched memory B-cells significantly decreased. CONCLUSIONS Abatacept directly targets B-cells by reducing CD80/CD86 expression. Impairment of antigen presentation and T-cell activation may result in altered B-cell selection,providing a new therapeutic mechanism and a base for abatacept use in B-cell mediated autoimmunity. View Publication

Circulating Tumor Cells (CTCs) represent an easy,repeatable and representative access to information regarding solid tumors. However,their detection remains difficult because of their paucity,their short half-life,and the lack of reliable surface biomarkers. Flow cytometry (FC) is a fast,sensitive and affordable technique,ideal for rare cells detection. Adapted to CTCs detection (i.e. extremely rare cells),most FC-based techniques require a time-consuming pre-enrichment step,followed by a 2-hours staining procedure,impeding on the efficiency of CTCs detection. We overcame these caveats and reduced the procedure to less than one hour,with minimal manipulation. First,cells were simultaneously fixed,permeabilized,then stained. Second,using low-speed FC acquisition conditions and two discriminators (cell size and pan-cytokeratin expression),we suppressed the pre-enrichment step. Applied to blood from donors with or without known malignant diseases,this protocol ensures a high recovery of the cells of interest independently of their epithelial-mesenchymal plasticity and can predict which samples are derived from cancer donors. This proof-of-concept study lays the bases of a sensitive tool to detect CTCs from a small amount of blood upstream of in-depth analyses. View Publication

BACKGROUND The goal of antiretroviral therapy (ART) is to suppress HIV-1 replication and reconstitute CD4+ T cells. Here,we report on HIV-infected individuals who had a paradoxical decline in CD4+ T cells despite ART-mediated suppression of plasma HIV-1 load (pVL). We defined such an immunological outcome as extreme immune decline (EXID). METHODS EXID's clinical and immunological characteristics were compared to immunological responders (IRs),immunological nonresponders (INRs),healthy controls (HCs),and idiopathic CD4+ lymphopenia (ICL) patients. T cell immunophenotyping and assembly/activation of inflammasomes were evaluated by flow cytometry. PBMC transcriptome analysis and genetic screening for pathogenic variants were performed. Levels of cytokines/chemokines were measured by electrochemiluminescence. Luciferase immunoprecipitation system and NK-mediated antibody-dependent cellular cytotoxicity (ADCC) assays were used to identify anti-lymphocyte autoantibodies. RESULTS EXIDs were infected with non-B HIV-1 subtypes and after 192 weeks of consistent ART-mediated pVL suppression had a median CD4+ decrease of 157 cells/mul,compared with CD4+ increases of 193 cells/mul and 427 cells/mul in INR and IR,respectively. EXID had reduced naive CD4+ T cells,but similar proportions of cycling CD4+ T cells and HLA-DR+CD38+CD8+ T cells compared with IR and INR. Levels of inflammatory cytokines were also similar in EXID and INR,but the IL-7 axis was profoundly perturbed compared with HC,IR,INR,and ICL. Genes involved in T cell and monocyte/macrophage function,autophagy,and cell migration were differentially expressed in EXID. Two of the 5 EXIDs had autoantibodies causing ADCC,while 2 different EXIDs had an increased inflammasome/caspase-1 activation despite consistently ART-suppressed pVL. CONCLUSIONS EXID is a distinct immunological outcome compared with previously described INR. Anti-CD4+ T cell autoantibodies and aberrant inflammasome/caspase-1 activation despite suppressed HIV-1 viremia are among the mechanisms responsible for EXID. View Publication

TET enzymes are dioxygenases that promote DNA demethylation by oxidizing the methyl group of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Here,we report a close correspondence between 5hmC-marked regions,chromatin accessibility and enhancer activity in B cells,and a strong enrichment for consensus binding motifs for basic region-leucine zipper (bZIP) transcription factors at TET-responsive genomic regions. Functionally,Tet2 and Tet3 regulate class switch recombination (CSR) in murine B cells by enhancing expression of Aicda,which encodes the activation-induced cytidine deaminase (AID) enzyme essential for CSR. TET enzymes deposit 5hmC,facilitate DNA demethylation,and maintain chromatin accessibility at two TET-responsive enhancer elements,TetE1 and TetE2,located within a superenhancer in the Aicda locus. Our data identify the bZIP transcription factor,ATF-like (BATF) as a key transcription factor involved in TET-dependent Aicda expression. 5hmC is not deposited at TetE1 in activated Batf-deficient B cells,indicating that BATF facilitates TET recruitment to this Aicda enhancer. Our study emphasizes the importance of TET enzymes for bolstering AID expression and highlights 5hmC as an epigenetic mark that captures enhancer dynamics during cell activation. View Publication

Intestinal fibrosis is a serious complication in inflammatory bowel disease (IBD). Despite the remarkable success of recent anti-inflammatory therapies for IBD,incidence of intestinal fibrosis and need for bowel resection have not significantly changed. To clarify the contribution of haematopoietic-derived cells in intestinal fibrosis,we prepared bone marrow (BM) chimeric mice (chimeras),which were reconstituted with BM cells derived from enhanced green fluorescent protein (EGFP)-transgenic mice or CC chemokine receptor 2 (CCR2)-deficient mice. After 2 months of transplantation,BM chimeras were treated with azoxymethane/dextran sodium sulphate. During chronic inflammation,CCR2+ BM-derived monocyte and fibrocyte infiltration into the colon and CC chemokine ligand 2 production increased,leading to colon fibrosis in EGFP BM chimeras. In CCR2-deficient BM chimeras,monocyte and fibrocyte numbers in the colonic lamina propria significantly decreased,and colon fibrosis was attenuated. In colon tissue,mRNA expression of tissue inhibitor of metalloproteinase (TIMP)-1 but not of collagen I,transforming growth factor-beta1 or matrix metalloproteinases was significantly different between the two chimeras. CCR2+ monocytes and fibrocytes showed high Timp1 mRNA expression. Our results suggest that infiltrating CCR2+ monocytes and their progenies,fibrocytes,promote colon fibrosis by inhibiting collagen degradation through TIMP-1 production. View Publication

The germinal center (GC) reaction in Peyer's patches (PP) requires continuous access to antigens,but how this is achieved is not known. Here we show that activated antigen-specific CCR6+CCR1+GL7- B cells make close contact with M cells in the subepithelial dome (SED). Using in situ photoactivation analysis of antigen-specific SED B cells,we find migration of cells towards the GC. Following antigen injection into ligated intestinal loops containing PPs,40{\%} of antigen-specific SED B cells bind antigen within 2 h,whereas unspecifc cells do not,indicating B cell-receptor involvment. Antigen-loading is not observed in M cell-deficient mice,but is unperturbed in mice depleted of classical dendritic cells (DC). Thus,we report a M cell-B cell antigen-specific transporting pathway in PP that is independent of DC. We propose that this antigen transporting pathway has a critical role in gut IgA responses,and should be taken into account when developing mucosal vaccines. View Publication