技术资料

A capability for analyzing complex cellular communication among tissues is important in drug discovery and development,and in vitro technologies for doing so are required for human applications. A prominent instance is communication between the gut and the liver,whereby perturbations of one tissue can influence behavior of the other. Here,we present a study on human gut-liver tissue interactions under normal and inflammatory contexts,via an integrative multi-organ platform comprising human liver (hepatocytes and Kupffer cells),and intestinal (enterocytes,goblet cells,and dendritic cells) models. Our results demonstrated long-term (>2 weeks) maintenance of intestinal (e.g.,barrier integrity) and hepatic (e.g.,albumin) functions in baseline interaction. Gene expression data comparing liver in interaction with gut,versus isolation,revealed modulation of bile acid metabolism. Intestinal FGF19 secretion and associated inhibition of hepatic CYP7A1 expression provided evidence of physiologically relevant gut-liver crosstalk. Moreover,significant non-linear modulation of cytokine responses was observed under inflammatory gut-liver interaction; for example,production of CXCR3 ligands (CXCL9,10,11) was synergistically enhanced. RNA-seq analysis revealed significant upregulation of IFNα/β/γ signaling during inflammatory gut-liver crosstalk,with these pathways implicated in the synergistic CXCR3 chemokine production. Exacerbated inflammatory response in gut-liver interaction also negatively affected tissue-specific functions (e.g.,liver metabolism). These findings illustrate how an integrated multi-tissue platform can generate insights useful for understanding complex pathophysiological processes such as inflammatory organ crosstalk. Biotechnol. Bioeng. 2017;114: 2648-2659. textcopyright 2017 Wiley Periodicals,Inc. View Publication

Macrophages are a source of both proinflammatory and restorative functions in damaged tissue through complex dynamic phenotypic changes. Here,we sought to determine whether monocyte-derived macrophages (MDMs) contribute to recovery after acute sterile brain injury. By profiling the transcriptional dynamics of MDMs in the murine brain after experimental intracerebral hemorrhage (ICH),we found robust phenotypic changes in the infiltrating MDMs over time and demonstrated that MDMs are essential for optimal hematoma clearance and neurological recovery. Next,we identified the mechanism by which the engulfment of erythrocytes with exposed phosphatidylserine directly modulated the phenotype of both murine and human MDMs. In mice,loss of receptor tyrosine kinases AXL and MERTK reduced efferocytosis of eryptotic erythrocytes and hematoma clearance,worsened neurological recovery,exacerbated iron deposition,and decreased alternative activation of macrophages after ICH. Patients with higher circulating soluble AXL had poor 1-year outcomes after ICH onset,suggesting that therapeutically augmenting efferocytosis may improve functional outcomes by both reducing tissue injury and promoting the development of reparative macrophage responses. Thus,our results identify the efferocytosis of eryptotic erythrocytes through AXL/MERTK as a critical mechanism modulating macrophage phenotype and contributing to recovery from ICH. View Publication

Dendritic cells (DCs) are a heterogeneous population of professional antigen-presenting cells and are key cells of the immune system,acquiring different phenotypes in accordance with their localization during the immune response. A subset of inflammatory DCs is derived from circulating monocytes (Mo) and has a key role in inflammation and infection. The pathways controlling Mo-DC differentiation are not fully understood. Our objective was to investigate the possible role of nicotinamide adenine dinucleotide phosphate reduced form oxidases (NOXs) in Mo-DC differentiation. In this study,we revealed that Mo-DC differentiation was inhibited by NOX inhibitors and reactive oxygen species scavengers. We show that the Mo-DC differentiation was dependent on p22phox,and not on gp91phox/NOX2,as shown by the reduced Mo-DC differentiation observed in chronic granulomatous disease patients lacking p22phox. Moreover,we revealed that NOX5 expression was strongly increased during Mo-DC differentiation,but not during Mo-macrophage differentiation. NOX5 was expressed in circulating myeloid DC,and at a lower level in plasmacytoid DC. Interestingly,NOX5 was localized at the outer membrane of the mitochondria and interacted with p22phox in Mo-DC. Selective inhibitors and small interfering RNAs for NOX5 indicated that NOX5 controlled Mo-DC differentiation by regulating the JAK/STAT/MAPK and NFκB pathways. These data demonstrate that the NOX5-p22phox complex drives Mo-DC differentiation,and thus could be critical for immunity and inflammation. View Publication

Pulmonary bacterial infections are a leading cause of death. Since the introduction of antibiotics,multidrug-resistant Klebsiella pneumoniae became an escalating threat. Therefore,development of methods to augment antibacterial defense is warranted. Neutrophil recruitment is critical to clear bacteria,and neutrophil migration in the lung requires the production of ELR(+) CXC chemokines. Although lung-specific CXCL1/keratinocyte cell-derived chemokine (KC) transgene expression causes neutrophil-mediated clearance of K. pneumoniae,the mechanisms underlying KC-mediated host defense against K. pneumoniae have not been explored. In this study,we delineated the host defense functions of KC during pulmonary K. pneumoniae infection using KC(-/-) mice. Our findings demonstrate that KC is important for expression of CXCL2/MIP-2 and CXCL5/LPS-induced CXC chemokine,and activation of NF-κB and MAPKs in the lung. Furthermore,KC derived from both hematopoietic and resident cells contributes to host defense against K. pneumoniae. Neutrophil depletion in mice before K. pneumoniae infection reveals no differences in the production of MIP-2 and LPS-induced CXC chemokine or activation of NF-κB and MAPKs in the lung. Using murine bone marrow-derived and alveolar macrophages,we confirmed KC-mediated upregulation of MIP-2 and activation of NF-κB and MAPKs on K. pneumoniae infection. Moreover,neutralizing KC in bone marrow-derived macrophages before K. pneumoniae challenge decreases bacteria-induced production of KC and MIP-2,and activation of NF-κB and MAPKs. These findings reveal the importance of KC produced by hematopoietic and resident cells in regulating pulmonary host defense against a bacterial pathogen via the activation of transcription factors and MAPKs,as well as the expression of cell adhesion molecules and other neutrophil chemoattractants. View Publication

Combined analyses of gene networks and DNA sequence variation can provide new insights into the aetiology of common diseases that may not be apparent from genome-wide association studies alone. Recent advances in rat genomics are facilitating systems-genetics approaches. Here we report the use of integrated genome-wide approaches across seven rat tissues to identify gene networks and the loci underlying their regulation. We defined an interferon regulatory factor 7 (IRF7)-driven inflammatory network (IDIN) enriched for viral response genes,which represents a molecular biomarker for macrophages and which was regulated in multiple tissues by a locus on rat chromosome 15q25. We show that Epstein-Barr virus induced gene 2 (Ebi2,also known as Gpr183),which lies at this locus and controls B lymphocyte migration,is expressed in macrophages and regulates the IDIN. The human orthologous locus on chromosome 13q32 controlled the human equivalent of the IDIN,which was conserved in monocytes. IDIN genes were more likely to associate with susceptibility to type 1 diabetes (T1D)-a macrophage-associated autoimmune disease-than randomly selected immune response genes (P = 8.85 × 10(-6)). The human locus controlling the IDIN was associated with the risk of T1D at single nucleotide polymorphism rs9585056 (P = 7.0 × 10(-10); odds ratio,1.15),which was one of five single nucleotide polymorphisms in this region associated with EBI2 (GPR183) expression. These data implicate IRF7 network genes and their regulatory locus in the pathogenesis of T1D. View Publication

The recruitment of monocytes and their differentiation into macrophages at sites of inflammation are key events in determining the outcome of the inflammatory response and initiating the return to tissue homeostasis. To study monocyte trafficking and macrophage differentiation in vivo,we have generated a novel transgenic reporter mouse expressing a green fluorescent protein (GFP) under the control of the human CD68 promoter. CD68-GFP mice express high levels of GFP in both monocyte and embryo-derived tissue resident macrophages in adult animals. The human CD68 promoter drives GFP expression in all CD115(+) monocytes of adult blood,spleen,and bone marrow; we took advantage of this to directly compare the trafficking of bone marrow-derived CD68-GFP monocytes to that of CX3CR1(GFP) monocytes in vivo using a sterile zymosan peritonitis model. Unlike CX3CR1(GFP) monocytes,which downregulate GFP expression on differentiation into macrophages in this model,CD68-GFP monocytes retain high-level GFP expression for 72 hours after differentiation into macrophages,allowing continued cell tracking during resolution of inflammation. In summary,this novel CD68-GFP transgenic reporter mouse line represents a powerful resource for analyzing monocyte mobilization and monocyte trafficking as well as studying the fate of recruited monocytes in models of acute and chronic inflammation. View Publication

The c-myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define its role during the hematopoietic lineage commitment,we silenced c-myb in human CD34(+) hematopoietic stem/progenitor cells. Noteworthy,c-myb silencing increased the commitment capacity toward the macrophage and megakaryocyte lineages,whereas erythroid differentiation was impaired,as demonstrated by clonogenic assay,morphologic and immunophenotypic data. Gene expression profiling and computational analysis of promoter regions of genes modulated in c-myb-silenced CD34(+) cells identified the transcription factors Kruppel-Like Factor 1 (KLF1) and LIM Domain Only 2 (LMO2) as putative targets,which can account for c-myb knockdown effects. Indeed,chromatin immunoprecipitation and luciferase reporter assay demonstrated that c-myb binds to KLF1 and LMO2 promoters and transactivates their expression. Consistently,the retroviral vector-mediated overexpression of either KLF1 or LMO2 partially rescued the defect in erythropoiesis caused by c-myb silencing,whereas only KLF1 was also able to repress the megakaryocyte differentiation enhanced in Myb-silenced CD34(+) cells. Our data collectively demonstrate that c-myb plays a pivotal role in human primary hematopoietic stem/progenitor cells lineage commitment,by enhancing erythropoiesis at the expense of megakaryocyte diffentiation. Indeed,we identified KLF1 and LMO2 transactivation as the molecular mechanism underlying Myb-driven erythroid versus megakaryocyte cell fate decision. View Publication

The type-III interferon (IFN) family is composed of 3 molecules in humans: IFN-lambda1 (interleukin-29 [IL-29]),IFN-lambda2 (IL-28A),and IFN-lambda3 (IL-28B),each of which signals through the same receptor complex. Plasmacytoid dendritic cells (pDCs) are major IFN-lambda producers among peripheral lymphocytes. Recently,it has been shown that IFN-lambda1 exerts a powerful inhibitory effect over the T-helper 2 (Th2) response by antagonizing the effect of IL-4 on CD4(+) T cells and inhibiting the production of Th2-associated cytokines. Here,we asked whether Th2 cytokines exert reciprocal control over IFN-lambda production. IL-4 treatment during stimulation of human peripheral lymphocytes significantly elevated IFN-lambda1 transcription and secretion. However,pDCs were not directly responsive to IL-4. Using depletion and reconstitution experiments,we showed that IL-4-responsive monocytes are an intermediary cell,responding to IL-4 by elevating their secretion of IL-1 receptor antagonist (IL-Ra); this IL-1Ra acts on pDCs to elevate their IFN-lambda1 output. Thus,our experiments revealed a novel mechanism for regulation of both IFN-lambda1 production and pDC function,and suggests an expanded immunomodulatory role for Th2-associated cytokines. View Publication

FNDC4 is a secreted factor sharing high homology with the exercise-associated myokine irisin (FNDC5). Here we report that Fndc4 is robustly upregulated in several mouse models of inflammation as well as in human inflammatory conditions. Specifically,FNDC4 levels are increased locally at inflamed sites of the intestine of inflammatory bowel disease patients. Interestingly,administration of recombinant FNDC4 in the mouse model of induced colitis markedly reduces disease severity compared with mice injected with a control protein. Conversely,mice lacking Fndc4 develop more severe colitis. Analysis of binding of FNDC4 to different immune cell types reveals strong and specific binding to macrophages and monocytes. FNDC4 treatment of bone marrow-derived macrophages in vitro results in reduced phagocytosis,increased cell survival and reduced proinflammatory chemokine expression. Hence,treatment with FNDC4 results in a state of dampened macrophage activity,while enhancing their survival. Thus,we have characterized FNDC4 as a factor with direct therapeutic potential in inflammatory bowel disease and possibly other inflammatory diseases. View Publication