搜索结果: 'gmp t cell activator'

In up to one-third of patients with acute myeloid leukemia,a C-terminal frame-shift mutation results in abnormal and abundant cytoplasmic accumulation of the usually nucleoli-bound protein nucleophosmin (NPM),and this is thought to function in cancer pathogenesis. Here,we demonstrate a gain-of-function role for cytoplasmic NPM in the inhibition of caspase signaling. The NPM mutant specifically inhibits the activities of the cell-death proteases,caspase-6 and -8,through direct interaction with their cleaved,active forms,but not the immature procaspases. The cytoplasmic NPM mutant not only affords protection from death ligand-induced cell death but also suppresses caspase-6/-8-mediated myeloid differentiation. Our data hence provide a potential explanation for the myeloid-specific involvement of cytoplasmic NPM in the leukemogenesis of a large subset of acute myeloid leukemia. View Publication

Taking advantage of fluorescent substrates for their metabolic marker aldehyde dehydrogenase (ALDH),hematopoietic stem cells (HSC) were defined as SSC(lo)ALDH(br) - reflecting their low orthogonal light scattering and bright fluorescence intensity in flow cytometry. Based thereon,we investigated the usefulness of ALDH activity for characterizing HSC graft quality,particularly under stress conditions. We first compared the expression of ALDH vs CD34 in bone marrow and peripheral blood stem cell (PBSC) samples over 7 days. We noted that (i) only ALDH activity but not CD34 expression strongly reflected colony-forming ability over time,and that (ii) PBSC grafts stored at room temperature lost most of their progenitor cells within just 48 h. We then retrospectively related ALDH and CD34 expression as well as granulocyte-macrophage colony-forming units (CFU-GM) potential for 19 cryopreserved allogeneic PBSC grafts to engraftment data. Strikingly,in all six patients who received markedly decreased numbers of SSC(lo)ALDH(br) cells,this was associated not only with almost complete loss of CFU-GM potential but also with delayed establishment/permanent absence of full hematopoietic donor cell chimerism,whereas all other patients showed early complete donor chimerism. In conclusion,we suggest to measure ALDH activity as a surrogate marker for HSC activity,and to transport and store PBSC under controlled cooling conditions. View Publication

Stem cells are undifferentiated cells defined by their ability to self-renew and differentiate to progenitors and terminally differentiated cells. Stem cells have been isolated from almost all tissues,and an emerging idea is that they share common characteristics such as the presence of ATP-binding cassette transporter G2 and high telomerase and aldehyde dehydrogenase (ALDH) activity,raising the hypothesis of a set of universal stem cell markers. In the present study,we describe the isolation of primitive neural stem cells (NSCs) from adult and embryonic murine neurospheres and dissociated tissue,based on the expression of high levels of ALDH activity. Single-cell suspension was stained with a fluorescent ALDH substrate termed Aldefluor and then analyzed by flow cytometry. A population of cells with low side scatter (SSC(lo)) and bright ALDH (ALDH(br)) activity was isolated. SSC(lo)ALDH(br) cells are capable of self-renewal and are able to generate new neurospheres and neuroepithelial stem-like cells. Furthermore,these cells are multipotent,differentiating both in neurons and macroglia,as determined by immunocytochemistry and real-time reverse transcription-polymerase chain reaction analysis. To evaluate the engraftment potential of SSC(lo)ALDH(br) cells in vivo,we transplanted them into mouse brain. Donor-derived neurons with mature morphology were detected in the cortex and subcortical areas,demonstrating the capacity of this cell population to differentiate appropriately in vivo. The ALDH expression assay is an effective method for direct identification of NSCs,and improvement of the stem cell isolation protocol may be useful in the development of a cell-mediated therapeutic strategy for neurodegenerative diseases. View Publication

The adult rat hippocampus contains fibroblast growth factor 2-responsive stem cells that are self-renewing and have the ability to generate both neurons and glia in vitro,but little is known about the molecular events that regulate stem cell differentiation. Hippocampus-derived stem cell clones were used to examine the effects of retinoic acid (RA) on neuronal differentiation. Exposure to RA caused an immediate up-regulation of NeuroD,increased p21 expression,and concurrent exit from cell cycle. These changes were accompanied by a threefold increase in the number of cells differentiating into immature neurons. An accompanying effect of RA was to sustain or up-regulate trkA,trkB,trkC,and p75NGFR expression. Without RA treatment,cells were minimally responsive to neurotrophins (NTs),whereas the sequential application of RA followed by brain-derived neurotrophic factor or NT-3 led to a significant increase in neurons displaying mature y-a-minobutyric acid,acetylcholinesterase,tyrosine hydroxylase,or calbindin phenotypes. Although NTs promoted maturation,they had little effect on the total number of neurons generated,suggesting that RA and neurotrophins acted at distinct stages in neurogenesis. RA first promoted the acquisition of a neuronal fate,and NTs subsequently enhanced maturation by way of RA-dependent expression of the Trk receptors. In combination,these sequential effects were sufficient to stimulate stem cell-derived progenitors to differentiate into neurons displaying a variety of transmitter phenotypes. View Publication

Mast cells (MCs) play an important role in the regulation of protective adaptive immune responses against pathogens. However,it is still unclear whether MCs promote such host defense responses via direct effects on T cells or rather by modifying the functions of antigen-presenting cells. To identify the underlying mechanisms of the immunoregulatory capacity of MCs,we investigated the impact of MCs on dendritic cell (DC) maturation and function. We found that murine peritoneal MCs underwent direct crosstalk with immature DCs that induced DC maturation as evidenced by enhanced expression of costimulatory molecules. Furthermore,the MC/DC interaction resulted in the release of the T-cell modulating cytokines IFN-γ,IL-2,IL-6 and TGF-β into coculture supernatants and increased the IL-12p70,IFN-γ,IL-6 and TGF-β secretion of LPS-matured DCs. Such MC-primed" DCs subsequently induced efficient CD4+ T-cell proliferation. Surprisingly� View Publication

Hearing loss due to damage to auditory hair cells is normally irreversible because mammalian hair cells do not regenerate. Here,we show that new hair cells can be induced and can cause partial recovery of hearing in ears damaged by noise trauma,when Notch signaling is inhibited by a γ-secretase inhibitor selected for potency in stimulating hair cell differentiation from inner ear stem cells in vitro. Hair cell generation resulted from an increase in the level of bHLH transcription factor Atoh1 in response to inhibition of Notch signaling. In vivo prospective labeling of Sox2-expressing cells with a Cre-lox system unambiguously demonstrated that hair cell generation resulted from transdifferentiation of supporting cells. Manipulating cell fate of cochlear sensory cells in vivo by pharmacological inhibition of Notch signaling is thus a potential therapeutic approach to the treatment of deafness. View Publication

The high mobility group A1 gene (HMGA1) has been previously implicated in breast carcinogenesis,and is considered an attractive target for therapeutic intervention because its expression is virtually absent in normal adult tissue. Other studies have shown that knockdown of HMGA1 reduces the tumorigenic potential of breast cancer cells in vitro. Therefore,we sought to determine if silencing HMGA1 can affect breast cancer development and metastatic progression in vivo. We silenced HMGA1 expression in the human breast cancer cell line MDA-MB-231 using an RNA interference vector,and observed a significant reduction in anchorage-independent growth and tumorsphere formation,which respectively indicate loss of tumorigenesis and self-renewal ability. Moreover,silencing HMGA1 significantly impaired xenograft growth in immunodeficient mice,and while control cells metastasized extensively to the lungs and lymph nodes,HMGA1-silenced cells generated only a few small metastases. Thus,our results show that interfering with HMGA1 expression reduces the tumorigenic and metastatic potential of breast cancer cells in vivo,and lend further support to investigations into targeting HMGA1 as a potential treatment for breast cancer. View Publication

CD8+ T cell longevity regulated by metabolic activity plays important roles in cancer immunotherapy. Although in vitro-polarized,transferred IL-9-secreting CD8+ Tc9 (cytotoxic T lymphocyte subset 9) cells exert greater persistence and antitumor efficacy than Tc1 cells,the underlying mechanism remains unclear. Here,we show that tumor-infiltrating Tc9 cells display significantly lower lipid peroxidation than Tc1 cells in several mouse models,which is strongly correlated with their persistence. Using RNA-sequence and functional validation,we found that Tc9 cells exhibited unique lipid metabolic programs. Tc9 cell-derived IL-9 activated STAT3,upregulated fatty acid oxidation and mitochondrial activity,and rendered Tc9 cells with reduced lipid peroxidation and resistance to tumor- or ROS-induced ferroptosis in the tumor microenvironment. IL-9 signaling deficiency,inhibiting STAT3,or fatty acid oxidation increased lipid peroxidation and ferroptosis of Tc9 cells,resulting in impaired longevity and antitumor ability. Similarly,human Tc9 cells also exhibited lower lipid peroxidation than Tc1 cells and tumor-infiltrating CD8+ T cells expressed lower IL9 and higher lipid peroxidation- and ferroptosis-related genes than circulating CD8+ T cells in patients with melanoma. This study indicates that lipid peroxidation regulates Tc9 cell longevity and antitumor effects via the IL-9/STAT3/fatty acid oxidation pathway and regulating T cell lipid peroxidation can be used to enhance T cell-based immunotherapy in human cancer. View Publication

Cancer stem cells (CSCs) residing in colorectal cancer tissues have tumorigenic capacity and contribute to chemotherapeutic resistance and disease relapse. It is well known that the survival of colorectal CSCs after 5-fluorouracil (5-FU)-based therapy leads to cancer recurrence. Thus CSCs represent a promising drug target. Here,we designed and synthesized novel hybrid molecules linking 5-FU with the plant-derived compound thymoquinone (TQ) and tested the potential of individual compounds and their combination to eliminate colorectal CSCs. Both,Combi and SARB hybrid showed augmented cytotoxicity against colorectal cancer cells,but were non-toxic to organoids prepared from healthy murine small intestine. NanoString analysis revealed a unique signature of deregulated gene expression in response to the combination of TQ and 5-FU (Combi) and SARB treatment. Importantly,two principle stem cell regulatory pathways WNT/{\ss}-Catenin and PI3K/AKT were found to be downregulated after Combi and hybrid treatment. Furthermore,both treatments strikingly eliminated CD133+ CSC population,accompanying the depleted self-renewal capacity by eradicating long-term propagated 3D tumor cell spheres at sub-toxic doses. In vivo xenografts on chicken eggs of SARB-treated HCT116 cells showed a prominent nuclear {\ss}-Catenin and E-cadherin staining. This was in line with the reduced transcriptional activity of {\ss}-Catenin and diminished cell adhesion under SARB exposure. In contrast to 5-FU,both,Combi and SARB treatment effectively reduced the angiogenic capacity of the remaining resistant tumor cells. Taken together,combination or hybridization of single compounds target simultaneously a broader spectrum of oncogenic pathways leading to an effective eradication of colorectal cancer cells. View Publication

Medulloblastoma (MB),the most frequent malignant childhood brain tumor,can arise from cellular malfunctions during hindbrain development. Here we generate humanized models for Sonic Hedgehog (SHH)-subgroup MB via MYCN overexpression in primary human hindbrain-derived neuroepithelial stem (hbNES) cells or iPSC-derived NES cells,which display a range of aggressive phenotypes upon xenografting. iPSC-derived NES tumors develop quickly with leptomeningeal dissemination,whereas hbNES-derived cells exhibit delayed tumor formation with less dissemination. Methylation and expression profiling show that tumors from both origins recapitulate hallmarks of infant SHH MB and reveal that mTOR activation,as a result of increased Oct4,promotes aggressiveness of human SHH tumors. Targeting mTOR decreases cell viability and prolongs survival,showing the utility of these varied models for dissecting mechanisms mediating tumor aggression and demonstrating the value of humanized models for a better understanding of pediatric cancers. View Publication

Human hematopoiesis starts at early yolk sac and undergoes site- and stage-specific changes over development. The intrinsic mechanism underlying property changes in hematopoiesis ontogeny remains poorly understood. Here,we analyzed single-cell transcriptome of human primary hematopoietic stem/progenitor cells (HSPCs) at different developmental stages,including yolk-sac (YS),AGM,fetal liver (FL),umbilical cord blood (UCB) and adult peripheral blood (PB) mobilized HSPCs. These stage-specific HSPCs display differential intrinsic properties,such as metabolism,self-renewal,differentiating potentialities etc. We then generated highly co-related gene regulatory network (GRNs) modules underlying the differential HSC key properties. Particularly,we identified GRNs and key regulators controlling lymphoid potentiality,self-renewal as well as aerobic respiration in human HSCs. Introducing selected regulators promotes key HSC functions in HSPCs derived from human pluripotent stem cells. Therefore,GRNs underlying key intrinsic properties of human HSCs provide a valuable guide to generate fully functional HSCs in vitro.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13619-024-00192-z. View Publication

Low Earth Orbit (LEO) has emerged as a unique environment for evaluating altered stem cell properties in microgravity. LEO has become increasingly accessible for research and development due to progress in private spaceflight. Axiom Mission 2 (Ax-2) was launched as the second all-private astronaut mission to the International Space Station (ISS). Frozen human induced pluripotent stem cells (hiPSCs) expressing green fluorescent protein (GFP) under the SOX2 promoter,as well as fibroblasts differentiated from SOX2-GFP hiPSCs,were sent to the ISS. Astronauts then thawed and seeded both cell types into commercially available 96-well plates,which provided surface tension that reduced fluid movement out of individual wells and showed that hiPSCs or hiPSC-derived fibroblasts could survive either in suspension or attached to a Matrigel substrate. Furthermore,both cell types could be transfected with red fluorescent protein (RFP)-expressing plasmid. We demonstrate that hiPSCs and hiPSC-fibroblasts can be thawed in microgravity in off-the-shelf,commercially-available cell culture hardware,can associate into 3D spheroids or grow adherently in Matrigel,and can be transfected with DNA. This lays the groundwork for future biomanufacturing experiments in space. View Publication