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Using time-lapse imaging,we have identified a series of bottlenecks that restrict growth of early-passage human embryonic stem cells (hESCs) and that are relieved by karyotypically abnormal variants that are selected by prolonged culture. Only a minority of karyotypically normal cells divided after plating,and these were mainly cells in the later stages of cell cycle at the time of plating. Furthermore,the daughter cells showed a continued pattern of cell death after division,so that few formed long-term proliferating colonies. These colony-forming cells showed distinct patterns of cell movement. Increasing cell density enhanced cell movement facilitating cell:cell contact,which resulted in increased proportion of dividing cells and improved survival postplating of normal hESCs. In contrast,most of the karyotypically abnormal cells reentered the cell cycle on plating and gave rise to healthy progeny,without the need for cell:cell contacts and independent of their motility patterns. ?? 2014 The Authors. View Publication

Directed neural differentiation of human embryonic stem cells (ESCs) enables researchers to generate diverse neuronal populations for human neural development study and cell replacement therapy. To realize this potential,it is critical to precisely understand the role of various endogenous and exogenous factors involved in neural differentiation. Cell density,one of the endogenous factors,is involved in the differentiation of human ESCs. Seeding cell density can result in variable terminal cell densities or localized cell densities (LCDs),giving rise to various outcomes of differentiation. Thus,understanding how LCD determines the differentiation potential of human ESCs is important. The aim of this study is to highlight the role of LCD in the differentiation of H9 human ESCs into neuroectoderm (NE),the primordium of the nervous system. We found the initially seeded cells form derived cells with variable LCDs and subsequently affect the NE differentiation. Using a newly established method for the quantitative examination of LCD,we demonstrated that in the presence of induction medium supplemented with or without SMAD signaling blockers,high LCD promotes the differentiation of NE. Moreover,SMAD signaling blockade promotes the differentiation of NE but not non-NE germ layers,which is dependent on high LCDs. Taken together,this study highlights the need to develop innovative strategies or techniques based on LCDs for generating neural progenies from human ESCs. View Publication

The generation of personalized induced pluripotent stem cells (iPSCs) followed by targeted genome editing provides an opportunity for developing customized effective cellular therapies for genetic disorders. However,it is critical to ascertain whether edited iPSCs harbor unfavorable genomic variations before their clinical application. To examine the mutation status of the edited iPSC genome and trace the origin of possible mutations at different steps,we have generated virus-free iPSCs from amniotic cells carrying homozygous point mutations in beta-hemoglobin gene (HBB) that cause severe beta-thalassemia (beta-Thal),corrected the mutations in both HBB alleles by zinc finger nuclease-aided gene targeting,and obtained the final HBB gene-corrected iPSCs by excising the exogenous drug resistance gene with Cre recombinase. Through comparative genomic hybridization and whole-exome sequencing,we uncovered seven copy number variations,five small insertions/deletions,and 64 single nucleotide variations (SNVs) in beta-Thal iPSCs before the gene targeting step and found a single small copy number variation,19 insertions/deletions,and 340 single nucleotide variations in the final gene-corrected beta-Thal iPSCs. Our data revealed that substantial but different genomic variations occurred at factor-induced somatic cell reprogramming and zinc finger nuclease-aided gene targeting steps,suggesting that stringent genomic monitoring and selection are needed both at the time of iPSC derivation and after gene targeting. View Publication

Notoginsenoside R1 (NGR1) is the main monomeric component extracted from the dried roots and rhizomes of Panax notoginseng,and exerts pharmacological action against myocardial infarction (MI). Owing to the differences in compound distribution,absorption,and metabolism in vivo,exploring a more effective drug delivery system with a high therapeutic targeting effect is crucial. In the early stages of MI,CD11b-expressing monocytes and neutrophils accumulate at infarct sites. Thus,we designed a mesoporous silica nanoparticle-conjugated CD11b antibody with loaded NGR1 (MSN-NGR1-CD11b antibody),which allowed NGR1 precise targeted delivery to the heart in a noninvasively manner. By increasing targeting to the injured myocardium,intravenous injection of MSN-NGR1-CD11b antibody nanoparticle in MI mice improved cardiac function and angiogenesis,reduced cell apoptosis,and regulate macrophage phenotype and inflammatory factors and chemokines. In order to further explore the mechanism of NGR1 protecting myocardium,cell oxidative stress model and oxygen-glucose deprivation (OGD) model were established. NGR1 protected H9C2 cells and primary cardiomyocytes against oxidative injury induced by H2O2 and OGD treatment. Further network pharmacology and molecular docking analyses suggested that the AKT,MAPK and Hippo signaling pathways were involved in the regulation of NGR1 in myocardial protection. Indeed,NGR1 could elevate the levels of p-Akt and p-ERK,and promote the nuclear translocation of YAP. Furthermore,LY294002 (AKT inhibitor),U0126 (ERK1/2 inhibitor) and Verteporfin (YAP inhibitor) administration in H9C2 cells indicated the involvement of AKT,MAPK and Hippo signaling pathways in NGR1 effects. Meanwhile,MSN-NGR1-CD11b antibody nanoparticles enhanced the activation of AKT and MAPK signaling pathways and the nuclear translocation of YAP at the infarcted site. Our research demonstrated that MSN-NGR1-CD11b antibody nanoparticle injection after MI enhanced the targeting of NGR1 to the infarcted myocardium and improved cardiac function. More importantly,our pioneering research provides a new strategy for targeting drug delivery systems to the ischemic niche. View Publication

Central nervous system (CNS) cancers are responsible for high rates of morbidity and mortality worldwide. Malignant CNS tumors such as adult Glioblastoma (GBM) and pediatric embryonal CNS tumors such as medulloblastoma (MED) and atypical teratoid rhabdoid tumors (ATRT) present relevant therapeutic challenges due to the lack of response to classic treatment regimens with radio and chemotherapy. Recent findings on the Zika virus’ (ZIKV) ability to infect and kill CNS neoplastic cells draw attention to the virus’ oncolytic potential. Studies demonstrating the safety of using ZIKV for treating malignant CNS tumors,enabling the translation of this approach to clinical trials,are scarce in the literature. Here we developed a co-culture model of mature human cerebral organoids assembled with GBM,MED or ATRT tumor cells and used these assembloids to test ZIKV oncolytic effect,replication potential and preferential targeting between normal and cancer cells. Our hybrid co-culture models allowed the tracking of tumor cell growth and invasion in cerebral organoids. ZIKV replication and ensuing accumulation in the culture medium was higher in organoids co-cultured with tumor cells than in isolated control organoids without tumor cells. ZIKV infection led to a significant reduction in tumor cell proportion in organoids with GBM and MED cells,but not with ATRT. Tumoroids (3D cultures of tumor cells alone) were efficiently infected by ZIKV. Interestingly,ZIKV rapidly replicated in GBM,MED,and ATRT tumoroids reaching significantly higher viral RNA accumulation levels than co-cultures. Moreover,ZIKV infection reduced viable cells number in MED and ATRT tumoroids but not in GBM tumoroids. Altogether,our findings indicate that ZIKV has greater replication rates in aggressive CNS tumor cells than in normal human cells comprising cerebral organoids. However,such higher ZIKV replication in tumor cells does not necessarily parallels oncolytic effects,suggesting cellular intrinsic and extrinsic factors mediating tumor cell death by ZIKV. View Publication

During gastrulation,the primitive streak (PS) forms and begins to differentiate into mesendodermal subtypes. This process involves an epithelial-mesenchymal transition (EMT),which is marked by cadherin switching,where E-Cadherin is downregulated,and N-Cadherin is upregulated. To understand the relationships between differentiation,EMT,and cadherin switching,we made measurements of these processes during differentiation of human pluripotent stem cells (hPSCs) to PS and subsequently to mesendoderm subtypes using established protocols,as well as variants in which signaling through key pathways including Activin,BMP,and Wnt were modulated. We found that perturbing signaling so that cells acquired identities ranging from anterior to posterior PS had little impact on the subsequent differentiation potential of cells but strongly impacted the degree of cadherin switching. The degree of E-Cadherin downregulation and N-Cadherin upregulation were uncorrelated and had different dependence on signaling. The exception to the broad potential of cells throughout the PS was the loss of definitive endoderm potential in cells with mid to posterior PS identities. Thus,cells induced to different PS coordinates had similar potential within the mesoderm but differed in cadherin switching. Consistently,E-Cadherin knockout did not alter cell fates outcomes during differentiation. Overall,cadherin switching and EMT are modulated independently of cell fate commitment in mesendodermal differentiation. View Publication

BackgroundSchizophrenia (SCZ) is a severe psychiatric disorder associated with alterations in early brain development. Details of underlying pathomechanisms remain unclear,despite genome and transcriptome studies providing evidence for aberrant cellular phenotypes and pathway deregulation in developing neuronal cells. However,mechanistic insight at the protein level is limited.MethodsHere,we investigate SCZ-specific protein expression signatures of neuronal progenitor cells (NPC) derived from patient iPSC in comparison to healthy controls using high-throughput Western Blotting (DigiWest) in a targeted proteomics approach.ResultsSCZ neural progenitors displayed altered expression and phosphorylation patterns related to Wnt and MAPK signaling,protein synthesis,cell cycle regulation and DNA damage response. Consistent with impaired cell cycle control,SCZ NPCs also showed accumulation in the G2/M cell phase and reduced differentiation capacity. Furthermore,we correlated these findings with elevated p53 expression and phosphorylation levels in SCZ patient-derived cells,indicating a potential implication of p53 in hampering cell cycle progression and efficient neurodevelopment in SCZ.ConclusionsThrough targeted proteomics we demonstrate that SCZ NPC display coherent mechanistic alterations in regulation of DNA damage response,cell cycle control and p53 expression. These findings highlight the suitability of iPSC-based approaches for modeling psychiatric disorders and contribute to a better understanding of the disease mechanisms underlying SCZ,particularly during early development.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12888-024-06127-x. View Publication

AbstractMyeloproliferative neoplasms (MPNs) are characterized by an increased production of blood cells due to the acquisition of mutations such as JAK2V617F. TGF‐β,whose secretion is increased in MPN patients,is known to negatively regulate haematopoietic stem cell (HSC) proliferation. Using an isogenic JAK2V617F or JAK2 wild‐type UT‐7 cell line we observed that JAK2V617F cells resist to TGF‐β antiproliferative activity. Although TGF‐β receptors and SMAD2/3 expressions are similar in both cell types,TGF‐β‐induced phosphorylation of SMAD2/3 is reduced in UT‐7 JAK2V617F cells compared with JAK2 WT cells. We confirmed that JAK2V617F mutated cells are resistant to the antiproliferative effect of TGF‐β in a competitive assay as we observed a positive selection of JAK2V617F cells when exposed to TGF‐β. Using cell lines,CD34‐positive cells from MPN patients and bone marrow cells from JAK2V617F knock‐in mice we identified a down regulation of the SHP‐1 phosphatase,which is required for the regulation of HSC quiescence by TGF‐β. The transduction of SHP‐1 cDNA (but not a phosphatase inactive cDNA) restores the antiproliferative effect of TGF‐β in JAK2V617F mutated cells. Finally,SC‐1,a known agonist of SHP‐1,antagonized the selection of JAK2V617F mutated cells in the presence of TGF‐β. In conclusion,we show a JAK2‐dependent down regulation of SHP‐1 in MPN patients' cells which is related to their resistance to the antiproliferative effect of TGF‐β. This may participate in the clonal selection of cancer cells in MPNs. View Publication

IntroductionCD8+ T cells are vital in the immune control of cancer and a key player in cell-based cancer immunotherapy. Recent studies have shown that microbial short-chain fatty acids (SCFA) can promote both effector and memory phenotypes in CD8+ T cells and may thereby enhance protection against cancer.MethodsIn this study,we determined the effect of SCFA butyrate on mouse CD8+ T cell function in vitro and in vivo,using the OT-I model.ResultsButyrate co-culture with anti-CD3 + anti-CD28 activated T cells in vitro enhanced the frequency of effector CD8+ IFN-γ-producing cells,and the amount of cytokine produced per cell. Culture with butyrate also enhanced the activation,TCR expression,and levels of phosphorylated mTOR proteins within CD8+ T cells but reduced proliferation rate and increased apoptosis. Butyrate-treated activated cells conferred tumor protection after adoptive transfer. Butyrate-treated cells were present at higher frequencies within the tumor compared to non-butyrate treated cells,and expressed IFN-γ. When analyzed using high dimensional cytometry,the tumors of mice that received butyrate-treated cells were enriched in clusters displaying an effector memory phenotype with high expression of IL-15Rβ and T-bet.DiscussionOur findings show that butyrate promotes the effector activity of CD8+ T cells in culture,which can persist in vivo while also stimulating memory phenotypes. Consequently,butyrate treatment may have strong application in T cell-based immunotherapies to improve protective cell functions and patient outcomes. View Publication

Venetoclax plus azacitidine treatment is clinically beneficial for elderly and unfit acute myeloid leukemia (AML) patients. However,the treatment is rarely curative,and relapse due to resistant disease eventually emerges. Since no current clinically feasible treatments are known to be effective at the state of acquired venetoclax resistance,this is becoming a major challenge in AML treatment. Studying venetoclax-resistant AML cell lines,we observed that venetoclax induced sublethal apoptotic signaling and DNA damage even though cell survival and growth were unaffected. This effect could be due to venetoclax inducing a sublethal degree of mitochondrial outer membrane permeabilization. Based on these results,we hypothesized that the sublethal apoptotic signaling induced by venetoclax could constitute a vulnerability in venetoclax-resistant AML cells. This was supported by screens with a broad collection of drugs,where we observed a synergistic effect between venetoclax and PARP inhibition in venetoclax-resistant cells. Additionally,the venetoclax-PARP inhibitor combination prevented the acquisition of venetoclax resistance in treatment naïve AML cell lines. Furthermore,the addition of azacitidine to the venetoclax-PARP inhibitor combination enhanced venetoclax induced DNA damage and exhibited exceptional sensitivity and long-term responses in the venetoclax-resistant AML cell lines and samples from AML patients that had clinically relapsed under venetoclax-azacitidine therapy. In conclusion,we mechanistically identify a new vulnerability in acquired venetoclax-resistant AML cells and identify PARP inhibition as a potential therapeutic approach to overcome acquired venetoclax resistance in AML. Subject terms: Acute myeloid leukaemia,Acute myeloid leukaemia View Publication

Circulating tumour cell (CTC) enumeration and profiling has been established as a valuable clinical tool in many solid malignancies. A key challenge in CTC research is the limited number of cells available for study. Ex vivo CTC culture permits expansion of these rare cell populations for detailed characterisation,functional assays including drug sensitivity testing,and investigation of the pathobiology of metastases. We report for the first time the establishment and characterisation of two continuous CTC lines from patients with gastroesophageal cancer. The two cell lines (designated UWG01CTC and UWG02CTC) demonstrated rapid tumorigenic growth in immunodeficient mice and exhibit distinct genotypic and phenotypic profiles which are consistent with the tumours of origin. UWG02CTC exhibits an EpCAM+,cytokeratin+,CD44+ phenotype,while UWG01CTC,which was derived from a patient with metastatic neuroendocrine cancer,displays an EpCAM-,weak cytokeratin phenotype,with strong expression of neuroendocrine markers. Further,the two cell lines show distinct differences in drug and radiation sensitivity which match differential cancer-associated gene expression pathways. This is strong evidence implicating EpCAM negative CTCs in metastasis. These novel,well characterised,long-term CTC cell lines from gastroesophageal cancer will facilitate ongoing research into metastasis and the discovery of therapeutic targets. View Publication

Ataxia with oculomotor apraxia type 1 (AOA1) is a rare,autosomal recessive,early-onset,progressive cerebellar ataxia caused by mutations in the APTX gene,which encodes aprataxin,a DNA-adenylate hydrolase involved in DNA damage repair. The pathogenesis of AOA1 remains unclear. The purpose of this study was to investigate the pathogenesis of a novel mutation,p.H201P/H201R,carried by our AOA1 patient and the mechanism of AOA1 in an induced pluripotent stem cells (iPSCs) model. We edited iPSCs derived from a healthy individual to carry the APTX homozygous mutation p.H201P (H201P-iPSCs) or p.H201R (H201R-iPSCs) via CRISPR/Cas9. We found that aprataxin expression was absent in both H201P- and H201R-iPSCs. The capacity of these APTX-mutant iPSCs to differentiate into neural progenitor cells (NPCs) and mature neurons was diminished. We observed an increase in DNA single-strand breaks (SSB) via a comet assay and poly(ADP-ribose) staining,and an increase in the ratio of cleaved PARP-1/total PARP-1 in APTX-mutant NPCs and early immature neurons (EiNs),in addition of a heightened sensitivity to tert-butyl hydroperoxide in APTX-mutant EiNs. Moreover,a decrease of APE1 expression was observed in APTX-mutant NPCs and H201R-EiNs during neural differentiation. Our study established a practical iPSCs model to investigate AOA1 disease. We found that mutant aprataxin leads to defective neural differentiation,accompanied by the accumulation of DNA SSBs with increased cleaved PARP-1 and reduced APE1 expression of the base excision repair pathway. View Publication