技术资料

Tissue resident intestinal macrophages are known to exhibit an anti-inflammatory phenotype and produce little pro-inflammatory cytokines upon TLR ligation,allowing symbiotic co-existence with the intestinal microbiota. However,upon acute events such as epithelial damage and concomitant influx of microbes,these macrophages must be able to quickly mount a pro-inflammatory response while more inflammatory macrophages are recruited from the blood stream simultaneously. Here,we show that dietary intake of vitamin A is required for the maintenance of the anti-inflammatory state of tissue resident intestinal macrophages. Interestingly,these anti-inflammatory macrophages were characterized by high levels of Dectin-1 expression. We show that Dectin-1 expression is enhanced by the vitamin A metabolite retinoic acid and our data suggests that Dectin-1 triggering might provide a switch to induce a rapid production of pro-inflammatory cytokines. In addition,Dectin-1 stimulation resulted in an altered metabolic profile which is linked to a pro-inflammatory response. Together,our data suggests that presence of vitamin A in the small intestine enhances an anti-inflammatory phenotype as well as Dectin-1 expression by macrophages and that this anti-inflammatory phenotype can rapidly convert toward a pro-inflammatory state upon Dectin-1 signaling. View Publication

Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here,we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFR$\alpha$+Sca1+ (P$\alpha$S) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition,chromatin structure and gene expression profiles,including the reduced expression of adhesion-related genes. Functionally,the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs,leading to reduced quiescence and diminished myeloid output. Most notably,HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus,genetic alterations in the BM niche lead to long-term functional changes of HSCs. View Publication

Thrombosis is a major cause of mortality in patients with myeloproliferative neoplasms (MPNs),though there is currently little to offer patients with MPN beyond aspirin and cytoreductive therapies such as hydroxyurea for primary prevention. Thrombogenesis in MPN involves multiple cellular mechanisms,including platelet activation and neutrophil-extracellular trap formation; therefore,an antithrombotic agent that targets one or more of these processes would be of therapeutic benefit in MPN. Here,we treated the JAK2V617F knockin mouse model of polycythemia vera with N-acetylcysteine (NAC),a sulfhydryl-containing compound with broad effects on glutathione replenishment,free radical scavenging,and reducing disulfide bonds,to investigate its antithrombotic effects in the context of MPN. Strikingly,NAC treatment extended the lifespan of JAK2V617F mice without impacting blood counts or splenomegaly. Using an acute pulmonary thrombosis model in vivo,we found that NAC reduced thrombus formation to a similar extent as the irreversible platelet inhibitor aspirin. In vitro analysis of platelet activation revealed that NAC reduced thrombin-induced platelet-leukocyte aggregate formation in JAK2V617F mice. Furthermore,NAC reduced neutrophil extracellular trap formation in primary human neutrophils from patients with MPN as well as healthy controls. These results provide evidence that N-acetylcysteine inhibits thrombosis in JAK2V617F mice and provide a pre-clinical rationale for investigating NAC as a therapeutic to reduce thrombotic risk in MPN. View Publication

Cancer stem cells are critical for cancer initiation,development,and treatment resistance. Our understanding of these processes,and how they relate to glioblastoma heterogeneity,is limited. To overcome these limitations,we performed single-cell RNA sequencing on 53586 adult glioblastoma cells and 22637 normal human fetal brain cells,and compared the lineage hierarchy of the developing human brain to the transcriptome of cancer cells. We find a conserved neural tri-lineage cancer hierarchy centered around glial progenitor-like cells. We also find that this progenitor population contains the majority of the cancer's cycling cells,and,using RNA velocity,is often the originator of the other cell types. Finally,we show that this hierarchal map can be used to identify therapeutic targets specific to progenitor cancer stem cells. Our analyses show that normal brain development reconciles glioblastoma development,suggests a possible origin for glioblastoma hierarchy,and helps to identify cancer stem cell-specific targets. View Publication

Preclinical in vitro models provide an essential tool to study cancer cell biology as well as aid in translational research,including drug target identification and drug discovery efforts. For any model to be clinically relevant,it needs to recapitulate the biology and cell heterogeneity of the primary tumor. We recently developed and described a conditional reprogramming (CR) cell technology that addresses many of these needs and avoids the deficiencies of most current cancer cell lines,which are usually clonal in origin. Here,we used the CR cell method to generate a collection of patient-derived cell cultures from non-small cell lung cancers (NSCLC). Whole exome sequencing and copy number variations are used for the first time to address the capability of CR cells to keep their tumor-derived heterogeneity. Our results indicated that these primary cultures largely maintained the molecular characteristics of the original tumors. Using a mutant-allele tumor heterogeneity (MATH) score,we showed that CR cells are able to keep and maintain most of the intra-tumoral heterogeneity,suggesting oligoclonality of these cultures. CR cultures therefore represent a pre-clinical lung cancer model for future basic and translational studies. View Publication

The limited ability of cytotoxic CD8+ T cells to infiltrate solid tumors and function within the tumor microenvironment presents a major roadblock to effective immunotherapy. Ion channels and Ca2+-dependent signaling events control the activity of T cells and are implicated in the failure of immune surveillance in cancer. Reduced KCa3.1 channel activity mediates the heightened inhibitory effect of adenosine on the chemotaxis of circulating T cells from head and neck squamous cell carcinoma (HNSCC) patients. Herein,we conducted experiments that elucidate the mechanisms of KCa3.1 dysfunction and impaired chemotaxis in HNSCC CD8+ T cells. The Ca2+ sensor calmodulin (CaM) controls multiple cellular functions including KCa3.1 activation. Our data showed that CaM expression is lower in HNSCC than healthy donor (HD) T cells. This reduction was due to an intrinsic decrease in the genes encoding CaM combined to the failure of HNSCC T cells to upregulate CaM upon activation. Furthermore,the reduction in CaM was confined to the plasma membrane and resulted in decreased CaM-KCa3.1 association and KCa3.1 activity (which was rescued by the delivery of CaM). IFN$\gamma$ production,also Ca2+- and CaM-dependent,was instead not reduced in HNSCC T cells,which maintained intact cytoplasmic CaM and Ca2+ fluxing ability. Knockdown of CaM in HD T cells decreased KCa3.1 activity,but not IFN$\gamma$ production,and reduced their chemotaxis in the presence of adenosine,thus recapitulating HNSCC T cell dysfunction. Activation of KCa3.1 with 1-EBIO restored the ability of CaM knockdown HD T cells to chemotax in the presence of adenosine. Additionally,1-EBIO enhanced INF$\gamma$ production. Our data showed a localized downregulation of membrane-proximal CaM that suppressed KCa3.1 activity in HNSCC circulating T cells and limited their ability to infiltrate adenosine-rich tumor-like microenvironments. Furthermore,they indicate that KCa3.1 activators could be used as positive CD8+ T cell modulators in cancers. View Publication

Cancer is believed to arise from stem cells,but mechanisms that limit the acquisition of mutations and tumor development have not been well defined. We show that a +4 stem cell (SC) in the gastric antrum,marked by expression of Cck2r (a GPCR) and Delta-like ligand 1 (DLL1),is a label-retaining cell that undergoes predominant asymmetric cell division. This +4 antral SC is Notch1low/ Numb+ and repressed by signaling from gastrin-expressing endocrine (G) cells. Chemical carcinogenesis of the stomach is associated with loss of G cells,increased symmetric stem cell division,glandular fission,and more rapid stem cell lineage tracing,a process that can be suppressed by exogenous gastrin treatment. This hormonal suppression is associated with a marked reduction in gastric cancer mutational load,as revealed by exomic sequencing. Taken together,our results show that gastric tumorigenesis is associated with increased symmetric cell division that facilitates mutation and is suppressed by GPCR signaling. View Publication

A promising strategy to limit cholera severity involves blockers mimicking the canonical cholera toxin ligand (CT) ganglioside GM1. However,to date the efficacies of most of these blockers have been evaluated in noncellular systems that lack ligands other than GM1. Importantly,the CT B subunit (CTB) has a noncanonical site that binds fucosylated structures,which in contrast to GM1 are highly expressed in the human intestine. Here we evaluate the capacity of norbornene polymers displaying galactose and/or fucose to block CTB binding to immobilized protein-linked glycan structures and also to primary human and murine small intestine epithelial cells (SI ECs). We show that the binding of CTB to human SI ECs is largely dependent on the noncanonical binding site,and interference with the canonical site has a limited effect while the opposite is observed with murine SI ECs. The galactose-fucose polymer blocks binding to fucosylated glycans but not to GM1. However,the preincubation of CT with the galactose-fucose polymer only partially blocks toxic effects on cultured human enteroid cells,while preincubation with GM1 completely blocks CT-mediated secretion. Our results support a model whereby the binding of fucose to the noncanonical site places CT in close proximity to scarcely expressed galactose receptors such as GM1 to enable binding via the canonical site leading to CT internalization and intoxication. Our finding also highlights the importance of complementing CTB binding studies with functional intoxication studies when assessing the efficacy inhibitors of CT. View Publication

BACKGROUND/OBJECTIVE A subset of neovascular age-related macular degeneration (nvAMD) subjects appears to be refractory to the effects of anti-VEGF treatment and require frequent intravitreal injections. The vascular phenotype of the choroidal neovascular (CNV) lesions may contribute to the resistance. Animal studies of CNV lesions have shown that cells originating from bone marrow are capable of forming varying cell types in the lesions. This raised the possibility of a similar cell population in human nvAMD subjects. MATERIALS AND METHODS Blood draws were obtained from subjects with active nvAMD while patients were receiving standard of care anti-VEGF injections. Subjects were classified as refractory or non-refractory to anti-VEGF treatment based on previous number of injections in the preceding 12 months. Peripheral blood mononuclear cells (PBMCs) were isolated and CD34-positive cells purified using magnetic bead sorting. The isolated cells were expanded in StemSpan SFEM media to increase cell numbers. After expansion,the cells were split and plated in either endothelial or mesenchymal promoting conditions. Phenotype analysis was performed via qPCR. RESULTS There was no significant difference in the number of PBMCs and CD34-positive cells between refractory and non-refractory nvAMD subjects. The growth pattern distribution between endothelial and mesenchymal media conditions were very similar between refractory and non-refractory subjects. qPCR and immunostaining demonstrated positive expression of endothelial markers in endothelial media,and markers such as NG2 and $\alpha$SMA in mesenchymal media. However,analysis of subsequent samples from AMD subjects demonstrated high variability in both the numbers and differentiation properties of this cell population. CONCLUSIONS CD34+ cells can be isolated from nvAMD subjects and show both endothelial and pericyte-like characteristics after differentiation in certain media conditions. However,nvAMD subjects show high variability in both numbers of cells and differentiation characteristics in repeat sampling. This variability highlights the importance of taking multiple samples from nvAMD subjects for any clinical trials focused on biomarkers for the disease. View Publication

Scleroderma (SSc) is an autoimmune connective tissue disease characterized by immune dysregulation,vasculopathy,and fibrosis. We have previously demonstrated that low Fli1 expression in SSc fibroblasts and endothelial cells plays an important role in SSc pathogenesis. Cells of myeloid and lymphoid origin also express Fli1 and are dysregulated in patients with SSc,playing key roles in disease pathogenesis. However,the role for immune Fli1 in SSc is not yet clear. Our aim was to elucidate whether Fli1 contributes to the immune dysregulation seen in SSc. Comparison of the expression of Fli1 in monocytes,B- and T-cell fractions of PBMCs isolated from SSc patients and healthy controls (HC),showed an increase in Fli1 levels in monocytes. We used siRNA transfected human myeloid cells and mouse peritoneal macrophages obtained from Fli1 flox/flox LysMCre+/+ mice,and found that markers of alternative macrophage activation were increased with Fli1 deletion. Coculture of Fli1-deficient myeloid cells and primary human or mouse fibroblasts resulted in a potent induction of collagen type I,independent of TGF$\beta$ upregulation. We next analyzed global gene expression profile in response to Fli1 downregulation,to gain further insight into the molecular mechanisms of this process and to identify differentially expressed genes in myeloid cells. Of relevance to SSc,the top most upregulated pathways were hallmark IFN-$\gamma$ and IFN-$\alpha$ response. Additionally,several genes previously linked to SSc pathogenesis and fibrosis in general were also induced,including CCL2,CCL7,MMP12,and CXCL10. ANKRD1,a profibrotic transcription co-regulator was the top upregulated gene in our array. Our results show that Fli1-deficient myeloid cells share key features with cells from SSc patients,with higher expression of profibrotic markers and activation of interferon responsive genes,thus suggesting that dysregulation of Fli1 in myeloid cells may contribute to SSc pathogenesis. View Publication

The incidence of Merkel cell carcinoma (MCC),a rare and highly metastatic skin malignancy,has sharply increased in the last decade. Clinical biomarkers are urgently needed for MCC prognosis,treatment response monitoring,and early diagnosis of relapse. The clinical interest of circulating tumors cells (CTCs) has been validated in many solid cancers. The aim of this study was to compare CTC detection and characterization in blood samples of patients with MCC using the CellSearch System and the RosetteSep -DEPArray workflow,an innovative procedure to enrich,detect and isolate single CTCs. In preliminary experiments (using spiked MCC cell lines) both methods allowed detecting very few MCC cells. In blood samples from 19 patients with MCC at different stages,CellSearch detected MCC CTCs in 26{\%} of patients,and the R-D workflow in 42{\%} of patients. The detection of CTC-positive patients increased to 52{\%} by the cumulative positivity rate of both methodologies. Moreover,Merkel cell polyomavirus DNA,involved in MCC oncogenesis,was detected in tumor biopsies,but not in all single CTCs from the same patient,reflecting the tumor heterogeneity. Our data demonstrate the possibility to detect,isolate and characterize CTCs in patients with MCC using two complementary approaches. View Publication

Seasonal and pandemic influenza infection remains a major public health concern worldwide. Driving robust humoral immunity has been a challenge given preexisting,often cross-reactive,immunity and in particular,poorly immunogenic avian antigens. To overcome immune barriers,the adjuvant MF59 has been used in seasonal influenza vaccines to increase antibody titers and improve neutralizing activity,translating to a moderate increase in protection in vulnerable populations. However,its effects on stimulating antibody effector functions,including NK cell activation,monocyte phagocytosis,and complement activity,all of which have been implicated in protection against influenza,have yet to be defined. Using systems serology,we assessed changes in antibody functional profiles in individuals who received H5N1 avian influenza vaccine administered with MF59,with alum,or delivered unadjuvanted. MF59 elicited antibody responses that stimulated robust neutrophil phagocytosis and complement activity. Conversely,vaccination with MF59 recruited NK cells poorly and drove moderate monocyte phagocytic activity,both likely compromised because of the induction of antibodies that did not bind FCGR3A. Collectively,defining the humoral antibody functions induced by distinct adjuvants may provide a path to designing next-generation vaccines that can selectively leverage the humoral immune functions,beyond binding and neutralization,resulting in better protection from infection. View Publication