技术资料

During the progression of autoimmune (type 1) diabetes,T cells and macrophages infiltrate the pancreas,disrupt islet function,and destroy insulin-producing beta cells. B-lymphocytes,particularly innate like B-cell populations such as marginal zone B cells and B-1 cells,have been implicated in many autoimmune diseases,and non-obese diabetic (NOD) mice that lack B cells do not develop spontaneous autoimmune diabetes. Hence,inhibitors of B cell signaling pathways could be useful for limiting the autoimmune processes that contribute to type 1 diabetes. Signaling via phosphoinositide 3-kinase (PI3K) regulates many cellular processes. The p110$\delta$ isoform of PI3K is expressed primarily in cells of hematopoietic origin and the catalytic activity of p110$\delta$ is important for B cell migration,activation,proliferation,and antigen presentation. Because innate-like B cells are particularly sensitive to inhibition of p110$\delta$ activity,and p110$\delta$ inhibitors also suppress pro-inflammatory functions of other cell types that contribute to autoimmunity,we tested whether a p110$\delta$ inhibitor could delay the onset or reduce the incidence of autoimmune diabetes in NOD mice. We found that long-term preventative treatment of pre-diabetic NOD mice with IC87114,a highly selective small molecule inhibitor of p110$\delta$,reduced the infiltration of inflammatory cells into the pancreatic islets and,accordingly,delayed and reduced the loss of glucose homeostasis. Moreover in a therapeutic treatment mode,IC87114 treatment conferred prolonged protection from progression to overt diabetes in a number of animals. These findings suggest that PI3K$\delta$ inhibitors could be useful for managing type 1 diabetes. View Publication

DNA double-strand breaks (DSB) are the most cytotoxic lesions induced by topoisomerase II poisons. Nonhomologous end joining (NHEJ) is a major pathway for DSB repair and requires DNA-dependent protein kinase (DNA-PK) activity. DNA-PK catalytic subunit (DNA-PKcs) is structurally similar to PI-3K,which promotes cell survival and proliferation and is upregulated in many cancers. KU-0060648 is a dual inhibitor of DNA-PK and PI-3K in vitro. KU-0060648 was investigated in a panel of human breast and colon cancer cells. The compound inhibited cellular DNA-PK autophosphorylation with IC(50) values of 0.019 $\mu$mol/L (MCF7 cells) and 0.17 $\mu$mol/L (SW620 cells),and PI-3K-mediated AKT phosphorylation with IC(50) values of 0.039 $\mu$mol/L (MCF7 cells) and more than 10 $\mu$mol/L (SW620 cells). Five-day exposure to 1 $\mu$mol/L KU-0060648 inhibited cell proliferation by more than 95{\%} in MCF7 cells but only by 55{\%} in SW620 cells. In clonogenic survival assays,KU-0060648 increased the cytotoxicity of etoposide and doxorubicin across the panel of DNA-PKcs-proficient cells,but not in DNA-PKcs-deficient cells,thus confirming that enhanced cytotoxicity was due to DNA-PK inhibition. In mice bearing SW620 and MCF7 xenografts,concentrations of KU-0060648 that were sufficient for in vitro growth inhibition and chemosensitization were maintained within the tumor for at least 4 hours at nontoxic doses. KU-0060648 alone delayed the growth of MCF7 xenografts and increased etoposide-induced tumor growth delay in both in SW620 and MCF7 xenografts by up to 4.5-fold,without exacerbating etoposide toxicity to unacceptable levels. The proof-of-principle in vitro and in vivo chemosensitization with KU-0060648 justifies further evaluation of dual DNA-PK and PI-3K inhibitors. View Publication

Pulmonary metastasis of breast cancer requires recruitment and expansion of T-regulatory cells (Treg) that promote escape from host protective immune cells. However,it remains unclear precisely how tumors recruit Tregs to support metastatic growth. Here we report the mechanistic involvement of a unique and previously undescribed subset of regulatory B cells. These cells,designated tumor-evoked Bregs (tBreg),phenotypically resemble activated but poorly proliferative mature B2 cells (CD19(+) CD25(High) CD69(High)) that express constitutively active Stat3 and B7-H1(High) CD81(High) CD86(High) CD62L(Low) IgM(Int). Our studies with the mouse 4T1 model of breast cancer indicate that the primary role of tBregs in lung metastases is to induce TGF-$\beta$-dependent conversion of FoxP3(+) Tregs from resting CD4(+) T cells. In the absence of tBregs,4T1 tumors cannot metastasize into the lungs efficiently due to poor Treg conversion. Our findings have important clinical implications,as they suggest that tBregs must be controlled to interrupt the initiation of a key cancer-induced immunosuppressive event that is critical to support cancer metastasis. View Publication

To investigate the difference in heart rate (HR) recovery after exercise between children and young adults,we administered a constant load of light exercise intensity and progressive treadmill exercise tests to nine children (aged 9 to 12 y,group A) and eight young adults (six male and two female,aged 17 to 21 y,group B) who had a history of Kawasaki disease without significant coronary arterial lesions. HR after both exercise protocols was analyzed. The low-frequency (LF) and high-frequency (HF) components of HR variability were measured,and LF/HF was calculated (log LF,log HF,log L/H). Arterial baroreflex sensitivity was assessed by the phenylephrine method. There were no differences between groups A and B in resting HR,peak HR,peak oxygen uptake,and decreases in systolic blood pressure during the recovery period. HR 1 and 2 min after peak exercise and 1 min after constant-load exercise was significantly lower in group A than in group B (p {\textless} 0.05),and the changes in HR from peak values after both exercise tests were also greater in group A than in group B (p {\textless} 0.05-0.01). Although no difference in arterial baroreflex sensitivity was observed,log HF was significantly higher in group A than in group B (p {\textless} 0.01),and log L/H was significantly lower in group A than in group B (p {\textless} 0.05). The value of log HF correlated inversely with the decrease in HR immediately after both exercise protocols (p {\textless} 0.05-0.01). Although log L/H correlated with the decrease in HR after peak exercise (p {\textless} 0.05-0.0005),the early decline in HR after constant-load exercise did not correlate with log L/H. Arterial baroreflex sensitivity did not correlate with the decrease in HR at any recovery time. These data suggest that the early phase of HR recovery after light to severe exercise is influenced by the cardiac parasympathetic nervous activity at rest and that the greater central cholinergic modulation of HR in children than in young adults may be responsible in part for children's faster HR recovery after exercise. View Publication

The tryptophan metabolite kynurenine has critical immunomodulatory properties and can function as an aryl hydrocarbon receptor (AHR) ligand. Here we show that the ability of T cells to transport kynurenine is restricted to cells activated by the T-cell antigen receptor or proinflammatory cytokines. Kynurenine is transported across the T-cell membrane by the System L transporter SLC7A5. Accordingly,the ability of kynurenine to activate the AHR is restricted to T cells that express SLC7A5. We use the fluorescence spectral properties of kynurenine to develop a flow cytometry-based assay for rapid,sensitive and quantitative measurement of the kynurenine transport capacity in a single cell. Our findings provide a method to assess the susceptibility of T cells to kynurenine,and a sensitive single cell assay to monitor System L amino acid transport. View Publication

Chronic myelomonocytic leukemia (CMML) is a clinically heterogeneous neoplasm in which JAK2 inhibition has demonstrated reductions in inflammatory cytokines and promising clinical activity. We hypothesize that annotation of inflammatory cytokines may uncover mutation-independent cytokine subsets associated with novel CMML prognostic features. A Luminex cytokine profiling assay was utilized to profile cryopreserved peripheral blood plasma from 215 CMML cases from three academic centers,along with center-specific,age-matched plasma controls. Significant differences were observed between CMML patients and healthy controls in 23 out of 45 cytokines including increased cytokine levels in IL-8,IP-10,IL-1RA,TNF-alpha$,IL-6,MCP-1/CCL2,hepatocyte growth factor (HGF),M-CSF,VEGF,IL-4,and IL-2RA. Cytokine associations were identified with clinical and genetic features,and Euclidian cluster analysis identified three distinct cluster groups associated with important clinical and genetic features in CMML. CMML patients with decreased IL-10 expression had a poor overall survival when compared to CMML patients with elevated expression of IL-10 (P = 0.017),even when adjusted for ASXL1 mutation and other prognostic features. Incorporating IL-10 with the Mayo Molecular Model statistically improved the prognostic ability of the model. These established cytokines,such as IL-10,as prognostically relevant and represent the first comprehensive study exploring the clinical implications of the CMML inflammatory state. View Publication

The intestine is maintained by stem cells located at the base of crypts and distinguished by the expression of LGR5. Genetically engineered mouse models have provided a wealth of information about intestinal stem cells,whereas less is known about human intestinal stem cells owing to difficulty detecting and isolating these cells. We established an organoid repository from patient-derived adenomas,adenocarcinomas and normal colon,which we analyzed for variants in 71 colorectal cancer (CRC)-associated genes. Normal and neoplastic colon tissue organoids were analyzed by immunohistochemistry and fluorescent-activated cell sorting for LGR5. LGR5-positive cells were isolated from four adenoma organoid lines and were subjected to RNA sequencing. We found that LGR5 expression in the epithelium and stroma was associated with tumor stage,and by integrating functional experiments with LGR5-sorted cell RNA sequencing data from adenoma and normal organoids,we found correlations between LGR5 and CRC-specific genes,including dickkopf WNT signaling pathway inhibitor 4 (DKK4) and SPARC-related modular calcium binding 2 (SMOC2). Collectively,this work provides resources,methods and new markers to isolate and study stem cells in human tissue homeostasis and carcinogenesis. View Publication

Replacing defective retinal pigment epithelial (RPE) cells with those derived from human embryonic stem cells (hESCs) or human-induced pluripotent stem cells (hiPSCs) is a potential strategy for treating retinal degenerative diseases. Early clinical trials have demonstrated that hESC-derived or hiPSC-derived RPE cells can be delivered safely as a suspension to the human eye. The next step is transplantation of hESC/hiPSC-derived RPE cells as cell sheets that are more physiological. We have developed a tissue-engineered product consisting of hESC-derived RPE cells grown as sheets on human amniotic membrane as a biocompatible substrate. We established a surgical approach to engraft this tissue-engineered product into the subretinal space of the eyes of rats with photoreceptor cell loss. We show that transplantation of the hESC-RPE cell sheets grown on a human amniotic membrane scaffold resulted in rescue of photoreceptor cell death and improved visual acuity in rats with retinal degeneration compared to hESC-RPE cells injected as a cell suspension. These results suggest that tissue-engineered hESC-RPE cell sheets produced under good manufacturing practice conditions may be a useful approach for treating diseases of retinal degeneration. View Publication

Zika virus (ZIKV) infects fetal and adult human brain and is associated with serious neurological complications. To date,no therapeutic treatment is available to treat ZIKV-infected patients. We performed a high-content chemical screen using human pluripotent stem cell-derived cortical neural progenitor cells (hNPCs) and found that hippeastrine hydrobromide (HH) and amodiaquine dihydrochloride dihydrate (AQ) can inhibit ZIKV infection in hNPCs. Further validation showed that HH also rescues ZIKV-induced growth and differentiation defects in hNPCs and human fetal-like forebrain organoids. Finally,HH and AQ inhibit ZIKV infection in adult mouse brain in vivo. Strikingly,HH suppresses viral propagation when administered to adult mice with active ZIKV infection,highlighting its therapeutic potential. Our approach highlights the power of stem cell-based screens and validation in human forebrain organoids and mouse models in identifying drug candidates for treating ZIKV infection and related neurological complications in fetal and adult patients. View Publication

Reports of multiple distinct mitoxantrone-resistant sublines without overexpression of P-glycoprotein or the multidrug-resistance associated protein have raised the possibility of the existence of another major transporter conferring drug resistance. In the present study,a cDNA library from mitoxantrone-resistant S1-M1-80 human colon carcinoma cells was screened by differential hybridization. Two cDNAs of different lengths were isolated and designated MXR1 and MXR2. Sequencing revealed a high degree of homology for the cDNAs with Expressed Sequence Tag sequences previously identified as belonging to an ATP binding cassette transporter. Homology to the Drosophila white gene and its homologues was found for the predicted amino acid sequence. Using either cDNA as a probe in a Northern analysis demonstrated high levels of expression in the S1-M1-80 cells and in the human breast cancer subline,MCF-7 AdVp3000. Levels were lower in earlier steps of selection,and in partial revertants. The gene is amplified 10-12-fold in the MCF-7 AdVp3000 cells,but not in the S1-M1-80 cells These studies are consistent with the identification of a new ATP binding cassette transporter,which is overexpressed in mitoxantrone-resistant cells. View Publication

MCF-7/AdrVp is a multidrug-resistant human breast cancer subline that displays an ATP-dependent reduction in the intracellular accumulation of anthracycline anticancer drugs in the absence of overexpression of known multidrug resistance transporters such as P glycoprotein or the multidrug resistance protein. RNA fingerprinting led to the identification of a 2.4-kb mRNA that is overexpressed in MCF-7/AdrVp cells relative to parental MCF-7 cells. The mRNA encodes a 655-aa [corrected] member of the ATP-binding cassette superfamily of transporters that we term breast cancer resistance protein (BCRP). Enforced expression of the full-length BCRP cDNA in MCF-7 breast cancer cells confers resistance to mitoxantrone,doxorubicin,and daunorubicin,reduces daunorubicin accumulation and retention,and causes an ATP-dependent enhancement of the efflux of rhodamine 123 in the cloned transfected cells. BCRP is a xenobiotic transporter that appears to play a major role in the multidrug resistance phenotype of MCF-7/AdrVp human breast cancer cells. View Publication

The Ly-49 family consists of at least nine members,of which Ly-49A and C have been found to be NK-cell inhibitory receptors specific for class I MHC. The functions of other Ly-49 molecules are still unclear. Further analysis of Ly-49 is complicated by the cross-reactivities of some anti-Ly-49 antibodies initially thought to be specific for individual Ly-49 molecules. Studies on the role of Ly-49 in hybrid resistance as well as on allelic exclusion are also complicated by our recent finding that a novel Ly-49CB6 gene is the likely allelic form of Ly-49CBALB as opposed to a previously reported highly related but distinct gene in B6 mice. In cell-cell binding assays,only Ly-49A and C show significant binding to class I MHC. Ly-49A and C also bind some polysaccharides,and carbohydrates on class I MHC seem to be important for its binding to Ly-49. However,this interaction involves not only the carbohydrate recognition domain of Ly-49 but also a part of the stalk region,suggesting that both carbohydrates and peptide backbone of class I MHC may be recognized by Ly-49. It is likely that additional Ly-49 molecules yet to be identified function as NK-inhibitory receptors specific for class I MHC. View Publication