技术资料

Dendritic cells (DC) play an essential role in innate immunity and radiation-elicited immune responses. LGP2 is a RIG-I like receptor (RLR) involved in cytoplasmic RNA recognition and anti-viral responses. Although LGP2 has also been linked to cell survival of both tumor cells and T cells,the role of LGP2 in mediating DC function and anti-tumor immunity elicited by radiotherapy remains unclear. Here we report that tumor DC are linked to the clinical outcome of breast cancer patients who received radiotherapy (RT) and the presence of DC correlates with gene expression of LGP2 in the tumor microenvironment. In preclinical models,host LGP2 was essential for optimal anti-tumor control by ionizing radiation (IR). The absence of LGP2 in DC dampened type I interferon production and the priming capacity of DC. In the absence of LGP2,MDA5-mediated activation of type I IFN signaling was abrogated. The MDA5/LGP2 agonist high molecular weight poly I: C improved the anti-tumor effect of IR. This study reveals a previously undefined role of LGP2 in host immunity and provides a new strategy to improve the efficacy of radiotherapy. View Publication

SARS-CoV-2,a $\beta$-coronavirus,has rapidly spread across the world,highlighting its high transmissibility,but the underlying morphogenesis and pathogenesis remain poorly understood. Here,we characterize the replication dynamics,cell tropism and morphogenesis of SARS-CoV-2 in organotypic human airway epithelial (HAE) cultures. SARS-CoV-2 replicates efficiently and infects both ciliated and secretory cells in HAE cultures. In comparison,HCoV-NL63 replicates to lower titers and is only detected in ciliated cells. SARS-CoV-2 shows a similar morphogenetic process as other coronaviruses but causes plaque-like cytopathic effects in HAE cultures. Cell fusion,apoptosis,destruction of epithelium integrity,cilium shrinking and beaded changes are observed in the plaque regions. Taken together,our results provide important insights into SARS-CoV-2 cell tropism,replication and morphogenesis. 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

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

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

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

The efficient generation of hepatocytes from human pluripotent stem cells (hPSCs) requires the induction of a proper endoderm population,broadly characterized by the expression of the cell surface marker CXCR4. Strategies to identify and isolate endoderm subpopulations predisposed to the liver fate do not exist. In this study,we generated mouse monoclonal antibodies against human embryonic stem cell-derived definitive endoderm with the goal of identifying cell surface markers that can be used to track the development of this germ layer and its specification to a hepatic fate. Through this approach,we identified two endoderm-specific antibodies,HDE1 and HDE2,which stain different stages of endoderm development and distinct derivative cell types. HDE1 marks a definitive endoderm population with high hepatic potential,whereas staining of HDE2 tracks with developing hepatocyte progenitors and hepatocytes. When used in combination,the staining patterns of these antibodies enable one to optimize endoderm induction and hepatic specification from any hPSC line. View Publication

The routine application of human pluripotent stem cells (hPSCs) and their derivatives in biomedicine and drug discovery will require the constant supply of high-quality cells by defined processes. Culturing hPSCs as cell-only aggregates in (three-dimensional [3D]) suspension has the potential to overcome numerous limitations of conventional surface-adherent (two-dimensional [2D]) cultivation. Utilizing single-use instrumented stirred-tank bioreactors,we showed that perfusion resulted in a more homogeneous culture environment and enabled superior cell densities of 2.85 X 10(6) cells per milliliter and 47% higher cell yields compared with conventional repeated batch cultures. Flow cytometry,quantitative reverse-transcriptase polymerase chain reaction,and global gene expression analysis revealed a high similarity across 3D suspension and 2D precultures,underscoring that matrix-free hPSC culture efficiently supports maintenance of pluripotency. Interestingly,physiological data and gene expression assessment indicated distinct changes of the cells' energy metabolism,suggesting a culture-induced switch from glycolysis to oxidative phosphorylation in the absence of hPSC differentiation. Our data highlight the plasticity of hPSCs' energy metabolism and provide clear physiological and molecular targets for process monitoring and further development. This study paves the way toward more efficient GMP-compliant cell production and underscores the enormous process development potential of hPSCs in suspension culture. SIGNIFICANCE Human pluripotent stem cells (hPSCs) are a unique source for the,in principle,unlimited production of functional human cell types in vitro,which are of high value for therapeutic and industrial applications. This study applied single-use,clinically compliant bioreactor technology to develop advanced,matrix-free,and more efficient culture conditions for the mass production of hPSCs in scalable suspension culture. Using extensive analytical tools to compare established conditions with this novel culture strategy,unexpected physiological features of hPSCs were discovered. These data allow a more rational process development,providing significant progress in the field of translational stem cell research and medicine. View Publication

The intestinal epithelial repair after injury is coordinated by intestinal stem cells (ISCs). Fucosylation catalyzed by fucosyltransferase 2 (FUT2) of the intestinal epithelium is beneficial to mucosal healing but poorly defined is the influence on ISCs. The dextran sulfate sodium (DSS) and lipopolysaccharide (LPS) model were used to assess the role of FUT2 on ISCs after injury. The apoptosis,function,and stemness of ISCs were analyzed using intestinal organoids from WT and Fut2?ISC (ISC-specific Fut2 knockout) mice incubated with LPS and fucose. N-glycoproteomics,UEA-1 chromatography,and site-directed mutagenesis were monitored to dissect the regulatory mechanism,identify the target fucosylated protein and the corresponding modification site. Fucose could alleviate intestinal epithelial damage via upregulating FUT2 and ?-1,2-fucosylation of ISCs. Oxidative stress,mitochondrial dysfunction,and cell apoptosis were impeded by fucose. Meanwhile,fucose sustained the growth and proliferation capacity of intestinal organoids treated with LPS. Contrarily,FUT2 depletion in ISCs aggravated the epithelial damage and disrupted the growth and proliferation capacity of ISCs via escalating LPS-induced endoplasmic reticulum (ER) stress and initiating the IRE1/TRAF2/ASK1/JNK branch of unfolded protein response (UPR). Fucosylation of the chaperone protein HYOU1 at the N-glycosylation site of asparagine (Asn) 862 mediated by FUT2 was identified to facilitate ISCs survival and self-renewal,and improve ISCs resistance to ER stress and inflammatory injury. Our study highlights a fucosylation-dependent protective mechanism of ISCs against inflammation,which may provide a fascinating strategy for treating intestinal injury disorders. View Publication

Acute coronary syndrome (ACS) is the most severe clinical manifestation of coronary heart disease.We performed an epigenome-wide analysis of circulating CD4+ and CD8+ T cells isolated from ACS patients and healthy subjects (HS),enrolled in the DIANA clinical trial,by reduced-representation bisulphite sequencing (RRBS). In CD4+ T cells,we identified 61 differentially methylated regions (DMRs) associated with 57 annotated genes (53% hyper- and 47% hypo-methylated) by comparing ACS patients vs HS. In CD8+ T cells,we identified 613 DMRs associated with 569 annotated genes (28% hyper- and 72% hypo-methylated) in ACS patients as compared to HS. In CD4+vs CD8+ T cells of ACS patients we identified 175 statistically significant DMRs associated with 157 annotated genes (41% hyper- and 59% hypo-methylated). From pathway analyses,we selected six differentially methylated hub genes (NFATC1,TCF7,PDGFA,PRKCB,PRKCZ,ABCA1) and assessed their expression levels by q-RT-PCR. We found an up-regulation of selected genes in ACS patients vs HS (P < 0.001). ABCA1,TCF7,PDGFA,and PRKCZ gene expression was positively associated with CK-MB serum concentrations (r = 0.75,P = 0.03; r = 0.760,P = 0.029; r = 0.72,P = 0.044; r = 0.74,P = 0.035,respectively).This pilot study is the first single-base resolution map of DNA methylome by RRBS in CD4+ and CD8+ T cells and provides specific methylation signatures to clarify the role of aberrant methylation in ACS pathogenesis,thus supporting future research for novel epigenetic-sensitive biomarkers in the prevention and early diagnosis of this pathology. View Publication

Despite the growing knowledge of T cell responses in COVID-19 patients,there is a lack of detailed characterizations for T cell-antigen interactions and T cell functions. Here,with a predicted peptide library from SARS-CoV-2 S and N proteins,we found that specific CD8+ T cell responses were identified in over 75% of COVID-19 convalescent patients (15/20) and an epitope from the N protein,N361-369 (KTFPPTEPK),was the most dominant epitope from our selected peptide library. Importantly,we discovered 2 N361-369-specific T cell receptors (TCRs) with high functional avidity that were independent of the CD8 co-receptor. These TCRs exhibited complementary cross-reactivity to several presently reported N361-369 mutant variants,as to the wild-type epitope. Further,the natural functions of these TCRs in the cytotoxic immunity against SARS-CoV-2 were determined with dendritic cells (DCs) and the lung organoid model. We found that the N361-369 epitope could be normally processed and endogenously presented by these different types of antigen presenting cells,to elicit successful activation and effective cytotoxicity of CD8+ T cells ex vivo. Our study evidenced potential mechanisms of cellular immunity to SARS-CoV-2,and illuminated potential ways of viral clearance in COVID-19 patients. These results indicate that utilizing CD8-independent TCRs against SARS-CoV-2-associated antigens may provide functional superiority that is beneficial for the adoptive cell immunotherapies based on natural or genetically engineered T cells. Additionally,this information is highly relevant for the development of the next-generation vaccines with protections against continuously emerged SARS-CoV-2 mutant strains. View Publication

Proton export is often considered a detoxifying process in animal cells,with monocarboxylate symporters coexporting excessive lactate and protons during glycolysis or the Warburg effect. We report a novel mechanism by which lactate/H+ export is sufficient to induce cell growth. Increased intracellular pH selectively activates catalysis by key metabolic gatekeeper enzymes HK1/PKM2/G6PDH,thereby enhancing glycolytic and pentose phosphate pathway carbon flux. The result is increased nucleotide levels,NADPH/NADP+ ratio,and cell proliferation. Simply increasing the lactate/proton symporter monocarboxylate transporter 4 (MCT4) or the sodium-proton antiporter NHE1 was sufficient to increase intracellular pH and give normal hematopoietic cells a significant competitive growth advantage in vivo. This process does not require additional cytokine triggers and is exploited in malignancy,where leukemogenic mutations epigenetically increase MCT4. Inhibiting MCT4 decreased intracellular pH and carbon flux and eliminated acute myeloid leukemia-initiating cells in mice without cytotoxic chemotherapy. Intracellular alkalization is a primitive mechanism by which proton partitioning can directly reprogram carbon metabolism for cell growth. View Publication