搜索结果: 'methocult media formulations for mouse hematopoietic cells serum containing'

Exosomes are cell-derived nanovesicles that hold promise as living vehicles for intracellular delivery of therapeutics to mammalian cells. This potential,however,is undermined by the lack of effective methods to load exosomes with therapeutic proteins and to facilitate their uptake by target cells. Here,we demonstrate how a vesicular stomatitis virus glycoprotein (VSVG) can both load protein cargo onto exosomes and increase their delivery ability via a pseudotyping mechanism. By fusing a set of fluorescent and luminescent reporters with VSVG,we show the successful targeting and incorporation of VSVG fusions into exosomes by gene transfection and fluorescence tracking. We subsequently validate our system by live cell imaging of VSVG and its participation in endosomes/exosomes that are ultimately released from transfected HEK293 cells. We show that VSVG pseudotyping of exosomes does not affect the size or distributions of the exosomes,and both the full-length VSVG and the VSVG without the ectodomain are shown to integrate into the exosomal membrane,suggesting that the ectodomain is not required for protein loading. Finally,exosomes pseudotyped with full-length VSVG are internalized by multiple-recipient cell types to a greater degree compared to exosomes loaded with VSVG without the ectodomain,confirming a role of the ectodomain in cell tropism. In summary,our work introduces a new genetically encoded pseudotyping platform to load and enhance the intracellular delivery of therapeutic proteins via exosome-based vehicles to target cells. View Publication

Ex vivo amplification of human hematopoietic stem cells (HSC) without loss of their self-renewing potential represents an important target for transplantation,gene and cellular therapies. Valproic acid is a safe and widely used neurologic agent that acts as a potent inhibitor of histone deacetylase activities. Here,we show that valproic acid addition to liquid cultures of human CD34+ cells isolated from cord blood,mobilized peripheral blood,and bone marrow strongly enhances the ex vivo expansion potential of different cytokine cocktails as shown by morphologic,cytochemical,immunophenotypical,clonogenic,and gene expression analyses. Notably,valproic acid highly preserves the CD34 positivity after 1 week (range,40-89%) or 3 weeks (range,21-52%) amplification cultures with two (Flt3L + thrombopoietin) or four cytokines (Flt3L + thrombopoietin + stem cell factor + interleukin 3). Moreover,valproic acid treatment increases histone H4 acetylation levels at specific regulatory sites on HOXB4,a transcription factor gene with a key role in the regulation of HSC self-renewal and AC133,a recognized marker gene for stem cell populations. Overall,our results relate the changes induced by valproic acid on chromatin accessibility with the enhancement of the cytokine effect on the maintenance and expansion of a primitive hematopoietic stem cell population. These findings underscore the potentiality of novel epigenetic approaches to modify HSC fate in vitro. View Publication

Bone marrow injury is a major adverse side effect of radiation and chemotherapy. Attempts to limit such damage are warranted,but their success requires a better understanding of how radiation and anticancer drugs harm the bone marrow. Here,we report one pivotal role of the BH3-only protein Puma in the radiosensitivity of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). Puma deficiency in mice confers resistance to high-dose radiation in a hematopoietic cell-autonomous manner. Unexpectedly,loss of one Puma allele is sufficient to confer mice radioresistance. Interestingly,null mutation in Puma protects both primitive and differentiated hematopoietic cells from damage caused by low-dose radiation but selectively protects HSCs and HPCs against high-dose radiation,thereby accelerating hematopoietic regeneration. Consistent with these findings,Puma is required for radiation-induced apoptosis in HSCs and HPCs,and Puma is selectively induced by irradiation in primitive hematopoietic cells,and this induction is impaired in Puma-heterozygous cells. Together,our data indicate that selective targeting of p53 downstream apoptotic targets may represent a novel strategy to protecting HSCs and HPCs in patients undergoing intensive cancer radiotherapy and chemotherapy. View Publication

The c-myb proto-oncogene encodes an obligate hematopoietic cell transcription factor important for lineage commitment,proliferation,and differentiation. Given its critical functions,c-Myb regulatory factors are of great interest but remain incompletely defined. Herein we show that c-Myb expression is subject to posttranscriptional regulation by microRNA (miRNA)-15a. Using a luciferase reporter assay,we found that miR-15a directly binds the 3'-UTR of c-myb mRNA. By transfecting K562 myeloid leukemia cells with a miR-15a mimic,functionality of binding was shown. The mimic decreased c-Myb expression,and blocked the cells in the G(1) phase of cell cycle. Exogenous expression of c-myb mRNA lacking the 3'-UTR partially rescued the miR-15a induced cell-cycle block. Of interest,the miR-15a promoter contained several potential c-Myb protein binding sites. Occupancy of one canonical c-Myb binding site was demonstrated by chromatin immunoprecipitation analysis and shown to be required for miR-15a expression in K562 cells. Finally,in studies using normal human CD34(+) cells,we showed that c-Myb and miR-15a expression were inversely correlated in cells undergoing erythroid differentiation,and that overexpression of miR-15a blocked both erythroid and myeloid colony formation in vitro. In aggregate,these findings suggest the presence of a c-Myb-miR-15a autoregulatory feedback loop of potential importance in human hematopoiesis. View Publication

Ex vivo culture of human hematopoietic cells is a crucial component of many therapeutic applications. Although current culture conditions have been optimized using quantitative in vitro progenitor assays,knowledge of the conditions that permit maintenance of primitive human repopulating cells is lacking. We report that primitive human cells capable of repopulating nonobese diabetic (NOD)/severe combined immunodeficiency (SCID) mice (SCID-repopulating cells; SRC) can be maintained and/or modestly increased after culture of CD34+CD38- cord blood cells in serum-free conditions. Quantitative analysis demonstrated a 4- and 10-fold increase in the number of CD34+CD38- cells and colony-forming cells,respectively,as well as a 2- to 4-fold increase in SRC after 4 d of culture. However,after 9 d of culture,all SRC were lost,despite further increases in total cells,CFC content,and CD34+ cells. These studies indicate that caution must be exercised in extending the duration of ex vivo cultures used for transplantation,and demonstrate the importance of the SRC assay in the development of culture conditions that support primitive cells. View Publication

The hematopoietic stem cell and multipotent progenitor (HSC/MPP) pool dynamically responds to stress to adapt blood output to specific physiological demands. In β-thalassemia (Bthal),severe anemia and ineffective erythropoiesis generate expansion of erythroid precursors and a chronic stress status in the bone marrow (BM) microenvironment. However,the response to the BM altered status at the level of the HSC/MPP compartment in terms of lineage commitment has not been investigated. Bulk and single-cell RNA-sequencing reveal that Bthal HSCs/MPPs are expanded and activated with enhanced priming along the whole Ery differentiation trajectory. Consistently,HSC/MPP showed an altered TGFβ expression and autophagy transcriptional signatures along with a declined dormancy state. We discovered that the altered TGFβ signaling fosters the Ery potential of HSCs by reducing their autophagic levels,and in vivo stimulation of autophagy is sufficient to rescue the imbalance of the HSC compartment. Our findings identify the interplay between TGFβ and HSC autophagy as a key driver in the context of non-malignant hematopoiesis. Subject terms: Haematopoietic stem cells,Haematological diseases,Autophagy View Publication

Human embryonic stem cells (hESC) are difficult to adapt to 96-well plate assays,such as the MTT assay,because they survive best when plated as colonies,which are not easily counted and plated accurately. Two methods were developed to address this problem. In the first,ROCK inhibitor (ROCKi) was used,which allows accurate counting and plating of single hESC. In the second,small colonies were plated without ROCKi but with adaptations for accurate counting and plating. The MTT assay was also adapted for use with mouse neural stem cells. These methods allow the MTT assay to be conducted rapidly and accurately with high reproducibility between replicate experiments. When screening volatile chemicals in a 96-well plate,vapor effects may occur and dose ranges must be carefully defined. The methods were validated using the NIH assay guidance tool. These methodss could readily be translated to other 96-well plate assay. View Publication

ABSTRACTBackgroundIdiopathic pulmonary fibrosis (IPF) is a lethal disease with an unknown etiology and complex pathophysiology that are not fully understood. The disease involves intricate cellular interplay,particularly among various immune cells. Currently,there is no treatment capable of reversing the fibrotic process or aiding lung regeneration. Hepatocyte growth factor (HGF) has demonstrated antifibrotic properties,whereas the adoptive transfer of modified T cells is a well‐established treatment for various malignancies. We aimed to understand the dynamics of T cells in the progression of lung fibrosis and to study the therapeutic benefit of adoptive T cell transfer in a bleomycin‐injured mouse lung (BLM) model.MethodsT cells were isolated from the spleen of naïve mice and transfected in vitro with mouse HGF plasmid and were administered intratracheally to the mice lungs 7 days post‐bleomycin injury to the lung. Lung tissue and bronchoalveolar lavage were collected and analyzed using flow cytometry,histology,qRT‐PCR,ELISA,and hydroxyproline assay.ResultsOur findings demonstrate the successful T cell therapy of bleomycin‐induced lung injury through the adoptive transfer of HGF‐transfected T cells in mice. This treatment resulted in decreased collagen deposition and a balancing of immune cell exhaustion and cytokine homeostasis compared with untreated controls. In vitro testing showed enhanced apoptosis in myofibroblasts induced by HGF‐overexpressing T cells.ConclusionsTaken together,our data highlight the great potential of adoptive T cell transfer as an emerging therapy to counteract lung fibrosis. This study explores the potential of T cells as a therapeutic strategy against idiopathic pulmonary fibrosis (IPF),a progressive lung disease for which there is currently no treatment to reverse fibrosis or restore normal lung function. To investigate an innovative approach using adoptive T cell transfer,T cells isolated from healthy mice were genetically modified to carry a plasmid containing hepatocyte growth factor (HGF). The modified cells were delivered directly into the airways of mice with bleomycin‐induced lung fibrosis. The results showed a significant reduction in fibrotic scarring,improved immune regulation,and increased apoptosis of pathogenic myofibroblasts. These results highlight the potential of HGF‐engineered T cells as a promising therapeutic approach to combat IPF. View Publication

Androgens have been used in the treatment of bone marrow failure syndromes without a clear understanding of their mechanism of action. Blood counts of patients with dyskeratosis congenita or aplastic anemia with mutations in telomerase genes can improve with androgen therapy. Here we observed that exposure in vitro of normal peripheral blood lymphocytes and human bone marrow-derived CD34(+) cells to androgens increased telomerase activity,coincident with higher TERT mRNA levels. Cells from patients who were heterozygous for telomerase mutations had low baseline telomerase activity,which was restored to normal levels by exposure to androgens. Estradiol had an effect similar to androgens on TERT gene expression and telomerase enzymatic activity. Tamoxifen abolished the effects of both estradiol and androgens on telomerase function,and letrozole,an aromatase inhibitor,blocked androgen effects on telomerase activity. Conversely,flutamide,an androgen receptor antagonist,did not affect androgen stimulation of telomerase. Down-regulation by siRNA of estrogen receptor-alpha (ER alpha),but not ER beta,inhibited estrogen-stimulated telomerase function. Our results provide a mechanism for androgen therapy in bone marrow failure: androgens appear to regulate telomerase expression and activity mainly by aromatization and through ER alpha. These findings have potential implications for the choice of current androgenic compounds and the development of future agents for clinical use. View Publication

Hematopoietic stem progenitor cells (HSPCs) undergo phenotypical and functional changes during their emergence and development. Although the molecular programs governing the development of human hematopoietic stem cells (HSCs) have been investigated broadly,the relationships between dynamic metabolic alterations and their functions remain poorly characterized. In this study,we comprehensively described the proteomics of HSPCs in the human fetal liver (FL),umbilical cord blood (UCB),and adult bone marrow (aBM). The metabolic state of human HSPCs was assessed via a Seahorse assay,RT‒PCR,and flow cytometry-based metabolic-related analysis. To investigate whether perturbing glutathione metabolism affects reactive oxygen species (ROS) production,the metabolic state,and the expansion of human HSPCs,HSPCs were treated with buthionine sulfoximine (BSO),an inhibitor of glutathione synthetase,and N-acetyl-L-cysteine (NAC). We investigated the metabolomic landscape of human HSPCs from the fetal,perinatal,and adult developmental stages by in-depth quantitative proteomics and predicted a metabolic switch from the oxidative state to the glycolytic state during human HSPC development. Seahorse assays,mitochondrial activity,ROS level,glucose uptake,and protein synthesis rate analysis supported our findings. In addition,immune-related pathways and antigen presentation were upregulated in UCB or aBM HSPCs,indicating their functional maturation upon development. Glutathione-related metabolic perturbations resulted in distinct responses in human HSPCs and progenitors. Furthermore,the molecular and immunophenotypic differences between human HSPCs at different developmental stages were revealed at the protein level for the first time. The metabolic landscape of human HSPCs at three developmental stages (FL,UCB,and aBM),combined with proteomics and functional validations,substantially extends our understanding of HSC metabolic regulation. These findings provide valuable resources for understanding human HSC function and development during fetal and adult life. The online version contains supplementary material available at 10.1186/s13287-024-03930-x. View Publication

To exploit the full potential of human pluripotent stem cells for regenerative medicine,developmental biology and drug discovery,defined culture conditions are needed. Media of known composition that maintain human embryonic stem (hES) cells have been developed,but finding chemically defined,robust substrata has proven difficult. We used an array of self-assembled monolayers to identify peptide surfaces that sustain pluripotent stem cell self-renewal. The effective substrates displayed heparin-binding peptides,which can interact with cell-surface glycosaminoglycans and could be used with a defined medium to culture hES cells for more than 3 months. The resulting cells maintained a normal karyotype and had high levels of pluripotency markers. The peptides supported growth of eight pluripotent cell lines on a variety of scaffolds. Our results indicate that synthetic substrates that recognize cell-surface glycans can facilitate the long-term culture of pluripotent stem cells. View Publication