参考文献

Background Progressive T cell decline in aged humans is associated with a deficiency of naive (TN) and central memory (TCM) T cells. We have previously reported increased tumor necrosis factor-? (TNF-?)-induced apoptosis in TN and TCM T cells in aged humans; however,the molecular basis of increased apoptosis remains to be defined. Since expression of TNF receptors (TNFRs) was reported to be comparable in young and aged,we investigated signaling events downstream of TNFRs to understand the molecular basis of increased TNF-?-induced apoptosis in aged TN and TCM CD8+ cells. Results The expression of TRAF-2 and RIP,phosphorylation of JNK,IKK?/?,and I?B?,and activation of NF-?B activation were significantly decreased in TN and TCM CD8+ cells from aged subjects as compared to young controls. Furthermore,expression of A20,Bcl-xL,cIAP1,and FLIP-L and FLIP-S was significantly decreased in TN and TCM CD8+ cells from aged subjects. Conclusions These data demonstrate that an impaired expression/function of molecules downstream TNFR signaling pathway that confer survival signals contribute to increased apoptosis of TN and TCM CD8+ cells in aged humans. View Publication

The classical model of hematopoiesis predicts a dichotomous lineage restriction of multipotent hematopoietic progenitors (MPPs) into common lymphoid progenitors (CLPs) and common myeloid progenitors (CMPs). However,this idea has been challenged by the identification of lymphoid progenitors retaining partial myeloid potential (e.g.,LMPPs),implying that granulocytes can arise within both the classical lymphoid and the myeloid branches. Here,we resolve this issue by using cell-surface CD133 expression to discriminate functional progenitor populations. We show that eosinophilic and basophilic granulocytes as well as erythrocytes and megakaryocytes derive from a common erythro-myeloid progenitor (EMP),whereas neutrophilic granulocytes arise independently within a lympho-myeloid branch with long-term progenitor function. These findings challenge the concept of a CMP and restore dichotomy to the classical hematopoietic model. View Publication

Recent compelling evidence indicates that Th17 confer host immunity against a variety of microbes,including extracellular and intracellular pathogens. Therefore,understanding mechanisms for the induction and activation of Ag-specific Th17 is important for the rational design of vaccines against pathogens. To study this,we employed an in vitro system in which influenza hemagglutinin (HA) 1 was delivered to dendritic cells (DCs) via Dectin-1 using anti-human Dectin-1 (hDectin-1)-HA1 recombinant fusion proteins. We found that healthy individuals maintained broad ranges of HA1-specific memory Th17 that were efficiently activated by DCs targeted with anti-hDectin-1-HA1. Nonetheless,these DCs were not able to induce a significant level of HA1-specific Th17 responses even in the presence of the Th17-promoting cytokines IL-1? and IL-6. We further found that the induction of surface IL-1R1 expression by signals via TCRs and common ?-chain receptors was essential for naive CD4(+) T cell differentiation into HA1-specific Th17. This process was dependent on MyD88,but not IL-1R-associated kinase 1/4. Thus,interruptions in STAT3 or MyD88 signaling led to substantially diminished HA1-specific Th17 induction. Taken together,the de novo generation of pathogen-specific human Th17 requires complex,but complementary,actions of multiple signals. Data from this study will help us design a new and effective vaccine strategy that can promote Th17-mediated immunity against microbial pathogens. View Publication

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is an exuberant stroma comprised of diverse cell types that enable or suppress tumor progression. Here,we explored the role of oncogenic KRAS in protumorigenic signaling interactions between cancer cells and host cells. We show that KRAS mutation (KRAS) drives cell-autonomous expression of type I cytokine receptor complexes (IL2r?–IL4r? and IL2r?–IL13r?1) in cancer cells that in turn are capable of receiving cytokine growth signals (IL4 or IL13) provided by invading Th2 cells in the microenvironment. Early neoplastic lesions show close proximity of cancer cells harboring KRAS and Th2 cells producing IL4 and IL13. Activated IL2r?–IL4r? and IL2r?–IL13r?1 receptors signal primarily via JAK1-STAT6. Integrated transcriptomic,chromatin occupancy,and metabolomic studies identified MYC as a direct target of activated STAT6 and that MYC drives glycolysis. Thus,paracrine signaling in the tumor microenvironment plays a key role in the KRAS-driven metabolic reprogramming of PDAC. SIGNIFICANCE: Type II cytokines,secreted by Th2 cells in the tumor microenvironment,can stimulate cancer cell-intrinsic MYC transcriptional upregulation to drive glycolysis. This KRAS-driven heterotypic signaling circuit in the early and advanced tumor microenvironment enables cooperative protumorigenic interactions,providing candidate therapeutic targets in the KRAS pathway for this intractable disease. View Publication

The intestinal epithelial regeneration is driven by intestinal stem cells under homeostatic conditions. Differentiated intestinal epithelial cells,such as Paneth cells,are capable of acquiring multipotency and contributing to regeneration upon the loss of intestinal stem cells. Paneth cells also support intestinal stem cell survival and regeneration. We report here that depletion of an RNA-binding protein named polypyrimidine tract binding protein 1 (PTBP1) in mouse intestinal epithelial cells causes intestinal stem cell death and epithelial regeneration failure. Mechanistically,we show that PTBP1 inhibits neuronal-like splicing programs in intestinal crypt cells,which is critical for maintaining intestinal stem cell stemness. This function is achieved at least in part through promoting the non-productive splicing of its paralog PTBP2. Moreover,PTBP1 inhibits the expression of an AKT inhibitor PHLDA3 in Paneth cells and permits AKT activation,which presumably maintains Paneth cell plasticity and function in supporting intestinal stem cell niche. We show that PTBP1 directly binds to a CU-rich region in the 3' UTR of Phlda3,which we demonstrate to be critical for downregulating the mRNA and protein levels of Phlda3. Our results thus reveal the multifaceted in vivo regulation of intestinal epithelial regeneration by PTBP1 at the post-transcriptional level. View Publication

While readily achieved in cell lines,the application of CRISPR-Cas9 gene editing in human-derived organoids suffers from limited efficacy and complex protocols. Here,we describe a multi-guide RNA CRISPR-Cas9 gene-editing protocol which efficiently achieves complete gene knockout in adult human colonic organoids. This protocol also describes crucial steps including how to harvest patient tissue to maximize gene-editing efficacy and a technique to validate gene knockout following editing with immunofluorescent staining of the organoids against the target protein. View Publication

Heartland virus (HRTV),a phlebovirus first isolated from two Missouri farmers in 2009,has been proposed to be transmitted to humans by the bite of infected Amblyomma americanum ticks. It is closely related to severe fever with thrombocytopenia syndrome virus (SFTSV) from China,another previously unrecognized phlebovirus that has subsequently been associated with hundreds of cases of severe disease in humans. To expand diagnostic capacity to detect HRTV infections,20 hybridoma clones secreting anti-HRTV murine monoclonal antibodies (MAbs) were developed using splenocytes from HRTV-inoculated AG129 alpha/beta and gamma interferon receptor-deficient mice. Nine of these MAbs were characterized herein for inclusion in future HRTV diagnostic assay development. All of the MAbs developed were found to be non-neutralizing and reactive to linear epitopes on HRTV nucleocapsid protein. MAb 2AF11 was found to be cross-reactive with SFTSV. View Publication

In cancer microenvironment,aberrant glycosylation events of ECM proteins and cell surface receptors occur. We developed a protocol to generate 3D bioprinted models of colorectal cancer (CRC) crosslinking hyaluronic acid and gelatin functionalized with three signalling glycans characterized in CRC,3'-Sialylgalactose,6'-Sialylgalactose and 2'-Fucosylgalactose. The crosslinking,performed exploiting azide functionalized gelatin and hyaluronic acid and 4arm-PEG-dibenzocyclooctyne,resulted in biocompatible hydrogels that were 3D bioprinted with commercial CRC cells HT-29 and patient derived CRC tumoroids. The glycosylated hydrogels showed good 3D printability,biocompatibility and stability over the time. SEM and synchrotron radiation SAXS/WAXS analysis revealed the influence of glycosylation in the construct morphology,whereas MALDI-MS imaging showed that protein profiles of tumoroid cells vary with glycosylation,indicating that sialylation and fucosylation of ECM proteins induce diverse alterations to the proteome of the tumoroid and surrounding cells. View Publication

Human intestinal organoids (HIOs) derived from pluripotent stem cells provide a valuable model for investigating human intestinal organogenesis and physiology,but they lack the immune components required to fully recapitulate the complexity of human intestinal biology and diseases. To address this issue and to begin to decipher human intestinal-immune crosstalk during development,we generated HIOs containing immune cells by transplanting HIOs under the kidney capsule of mice with a humanized immune system. We found that human immune cells temporally migrate to the mucosa and form cellular aggregates that resemble human intestinal lymphoid follicles. Moreover,after microbial exposure,epithelial microfold cells are increased in number,leading to immune cell activation determined by the secretion of IgA antibodies in the HIO lumen. This in vivo HIO system with human immune cells provides a framework for future studies on infection- or allergen-driven intestinal diseases. View Publication

Abs have been shown to be protective in passive immunotherapy of tuberculous infection using mouse experimental models. In this study,we report on the properties of a novel human IgA1,constructed using a single-chain variable fragment clone (2E9),selected from an Ab phage library. The purified Ab monomer revealed high binding affinities for the mycobacterial ?-crystallin Ag and for the human Fc?RI (CD89) IgA receptor. Intranasal inoculations with 2E9IgA1 and recombinant mouse IFN-? significantly inhibited pulmonary H37Rv infection in mice transgenic for human CD89 but not in CD89-negative littermate controls,suggesting that binding to CD89 was necessary for the IgA-imparted passive protection. 2E9IgA1 added to human whole-blood or monocyte cultures inhibited luciferase-tagged H37Rv infection although not for all tested blood donors. Inhibition by 2E9IgA1 was synergistic with human rIFN-? in cultures of purified human monocytes but not in whole-blood cultures. The demonstration of the mandatory role of Fc?RI (CD89) for human IgA-mediated protection is important for understanding of the mechanisms involved and also for translation of this approach toward development of passive immunotherapy of tuberculosis. View Publication