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

Lysophosphatidic acid (LPA) is enriched in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests cancer-associated myofibroblasts play a pivotal role in tumorigenesis through secreting stromal cell-derived factor-1 (SDF-1). In the present study,we demonstrate that LPA induces expression of alpha-smooth muscle actin (alpha-SMA),a marker for myofibroblasts,in human adipose tissue-derived mesenchymal stem cells (hADSCs). The LPA-induced expression of alpha-SMA was completely abrogated by pretreatment of the cells with Ki16425,an antagonist of LPA receptors,or by silencing LPA(1) or LPA(2) isoform expression with small interference RNA (siRNA). LPA elicited phosphorylation of Smad2/3,and siRNA-mediated depletion of endogenous Smad2/3 or adenoviral expression of Smad7,an inhibitory Smad,abrogated the LPA induced expression of alpha-SMA and phosphorylation of Smad2/3. LPA-induced secretion of transforming growth factor (TGF)-beta1 in hADSCs,and pretreatment of the cells with SB431542,a TGF-beta type I receptor kinase inhibitor,or anti-TGF-beta1 neutralizing antibody inhibited the LPA-induced expression of alpha-SMA and phosphorylation of Smad2. Furthermore,ascites from ovarian cancer patients or conditioned medium from ovarian cancer cells induced expression of alpha-SMA and phosphorylation of Smad2,and pretreatment of the cells with Ki16425 or SB431542 abrogated the expression of alpha-SMA and phosphorylation of Smad2. In addition,LPA increased the expression of SDF-1 in hADSCs,and pretreatment of the cells with Ki16425 or SB431562 attenuated the LPA-stimulated expression of SDF-1. These results suggest that cancer-derived LPA stimulates differentiation of hADSCs to myofibroblast-like cells and increases SDF-1 expression through activating autocrine TGF-beta1-Smad signaling pathway. View Publication

Precise,robust and scalable directed differentiation of pluripotent stem cells is an important goal with respect to disease modeling or future therapies. Using the AggreWell™400 system we have standardized the differentiation of human embryonic and induced pluripotent stem cells to a neuronal fate using defined conditions. This allows reproducibility in replicate experiments and facilitates the direct comparison of cell lines. Since the starting point for EB formation is a single cell suspension,this protocol is suitable for standard and novel methods of pluripotent stem cell culture. Moreover,an intermediate population of neural precursor cells,which are routinely textgreater95% NCAM(pos) and Tra-1-60(neg) by FACS analysis,may be expanded and frozen prior to differentiation allowing a convenient starting point for downstream experiments. View Publication

BACKGROUND: Induced pluripotent stem (iPS) cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming,which uses a defined set of transcription factors,iPS cells represent important sources of patient-specific cells for clinical applications. However,before these cells can be used in therapeutic designs,it is essential to understand their genetic stability. METHODOLOGY/PRINCIPAL FINDINGS: Here,we describe DNA damage responses in human iPS cells. We observe hypersensitivity to DNA damaging agents resulting in rapid induction of apoptosis after γ-irradiation. Expression of pluripotency factors does not appear to be diminished after irradiation in iPS cells. Following irradiation,iPS cells activate checkpoint signaling,evidenced by phosphorylation of ATM,NBS1,CHEK2,and TP53,localization of ATM to the double strand breaks (DSB),and localization of TP53 to the nucleus of NANOG-positive cells. We demonstrate that iPS cells temporary arrest cell cycle progression in the G(2) phase of the cell cycle,displaying a lack of the G(1)/S cell cycle arrest similar to human embryonic stem (ES) cells. Furthermore,both cell types remove DSB within six hours of γ-irradiation,form RAD51 foci and exhibit sister chromatid exchanges suggesting homologous recombination repair. Finally,we report elevated expression of genes involved in DNA damage signaling,checkpoint function,and repair of various types of DNA lesions in ES and iPS cells relative to their differentiated counterparts. CONCLUSIONS/SIGNIFICANCE: High degrees of similarity in DNA damage responses between ES and iPS cells were found. Even though reprogramming did not alter checkpoint signaling following DNA damage,dramatic changes in cell cycle structure,including a high percentage of cells in the S phase,increased radiosensitivity and loss of DNA damage-induced G(1)/S cell cycle arrest,were observed in stem cells generated by induced pluripotency. View Publication

The introduction of antibody–drug conjugates represents a significant advancement in targeted therapy of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Our study aims to investigate the role of the DNA damage response pathway and the impact of PARP1 inhibition,utilizing talazoparib,on the response of AML and ALL cells to Gemtuzumab ozogamicin (GO) and Inotuzumab ozogamicin (INO),respectively. AML and ALL cells were treated with GO,INO and γ-calicheamicin in order to induce severe DNA damage and activate the G2/M cell-cycle checkpoint in a dose- and time-dependent manner. The efficacy of PARP1 inhibitors and,in particular,talazoparib in enhancing INO or GO against ALL or AML cells was assessed through measurements of cell viability,cell death,cell cycle progression,DNA damage repair,accumulation of mitotic DNA damage and inhibition of clonogenic capacity. We observed that both ALL and AML cell lines activate the G2/M cell-cycle checkpoint in response to γ-calicheamicin-induced DNA damage,highlighting a shared cellular response mechanism. Talazoparib significantly enhanced the efficacy of INO against ALL cell lines,resulting in reduced cell viability,increased cell death,G2/M cell-cycle checkpoint override,accumulation of mitotic DNA damage and inhibition of clonogenic capacity. Strong synergism was observed in primary ALL cells treated with the combination. In contrast,AML cells exhibited a heterogeneous response to talazoparib in combination with GO. Our findings suggest a potential link between the differential responses of ALL and AML cells to the drug combinations and the ability of talazoparibto override G2/M cell-cycle arrest induced by antibody–drug conjugates. PARP1 emerges as a key player in the response of ALL cells to INO and represents a promising target for therapeutic intervention in this leukemia setting. Our study sheds light on the intricate interplay between the DNA damage response pathway,PARP1 inhibition,and response of γ-calicheamicin-induced DNA damages in AML and ALL. These findings underscore the importance of targeted therapeutic strategies and pave the way for future research aimed at optimizing leukemia treatment approaches. The online version contains supplementary material available at 10.1186/s12967-024-05838-9. View Publication

We present a novel and efficient non-integrating gene expression system in human embryonic stem cells (hESc) utilizing human artificial chromosomes (HAC),which behave as autonomous endogenous host chromosomes and segregate correctly during cell division. HAC are important vectors for investigating the organization and structure of the kinetochore,and gene complementation. HAC have so far been obtained in immortalized or tumour-derived cell lines,but never in stem cells,thus limiting their potential therapeutic application. In this work,we modified the herpes simplex virus type 1 amplicon system for efficient transfer of HAC DNA into two hESc. The deriving stable clones generated green fluorescent protein gene-expressing HAC at high frequency,which were stably maintained without selection for 3 months. Importantly,no integration of the HAC DNA was observed in the hESc lines,compared with the fibrosarcoma-derived control cells,where the exogenous DNA frequently integrated in the host genome. The hESc retained pluripotency,differentiation and teratoma formation capabilities. This is the first report of successfully generating gene expressing de novo HAC in hESc,and is a significant step towards the genetic manipulation of stem cells and potential therapeutic applications. View Publication

Human pluripotent stem cells (PSCs),which include human embryonic stem cells (ESCs) as well as induced pluripotent stem cells (iPSCs),represent an important source of cellular therapies in regenerative medicine and the study of early human development. As such,it is becoming increasingly important to develop methods for the large-scale banking of human PSC lines. There are several well-established methods for the propagation of human PSCs. The key to development of a good manufacturing practice (GMP) bank is to determine a manufacturing method that is amenable to large-scale production using materials that are fully documented. We have developed several banks of hESCs using animal feeder cells,animal-based matrices,or animal-free matrices. Protocols for growing hESCs on mouse embryonic fibroblasts (MEFs) are well established and are very helpful for producing research grade banks of cells. As most human ESCs cultured by research laboratories have been exposed to xenogeneic reagents,it is not imperative that all materials used in the production of a master cell bank be animal-free in origin. Nevertheless,as the field develops,it will no doubt become increasingly important to produce a bank of cells for clinical use without xenogeneic reagents,particularly nonhuman feeder cells which might harbor viruses with potential risk to human health or cell product integrity. Thus,even for cell lines previously exposed to xenogeneic reagents,it is important to minimize any subsequent exposure of the cell lines to additional adventitious agents. We have specifically described procedures for the growth of hESCs on Matrigel,an animal-matrix,and CELLstart,an animal-free matrix,and these can be used to produce hESCs as part of a clinical manufacturing process. View Publication

X-ALD is an inherited neurodegenerative disorder where mutations in the ABCD1 gene result in clinically diverse phenotypes: the fatal disorder of cerebral childhood ALD (cALD) or a milder disorder of adrenomyeloneuropathy (AMN). The various models used to study the pathobiology of X-ALD disease lack the appropriate presentation for different phenotypes of cALD vs AMN. This study demonstrates that induced pluripotent stem cells (IPSC) derived brain cells astrocytes (Ast),neurons and oligodendrocytes (OLs) express morphological and functional activities of the respective brain cell types. The excessive accumulation of saturated VLCFA,a hallmark" of X-ALD� View Publication

NK cells are key innate immune cells that play critical roles in host defense. Although NK cells have been shown to regulate immunity to some infectious diseases,their role in immunity to Trypanosoma congolense has not been investigated. NK cells are vital sources of IFN-gamma and TNF-alpha; two key cytokines that are known to play important roles in resistance to African trypanosomes. In this article,we show that infection with T. congolense leads to increased levels of activated and functional NK cells in multiple tissue compartments. Systemic depletion of NK cells with anti-NK1.1 mAb led to increased parasitemia,which was accompanied by significant reduction in IFN-gamma production by immune cells in the spleens and liver of infected mice. Strikingly,infected NFIL3-/- mice (which genetically lack NK cell development and function) on the normally resistant background were highly susceptible to T. congolense infection. These mice developed fulminating and uncontrolled parasitemia and died significantly earlier (13 ± 1 d) than their wild-type control mice (106 ± 26 d). The enhanced susceptibility of NFIL3-/- mice to infection was accompanied by significantly impaired cytokine (IFN-gamma and TNF-alpha) response by CD3+ T cells in the spleens and liver. Adoptive transfer of NK cells into NFIL3-/- mice before infection rescued them from acute death in a perforin-dependent manner. Collectively,these studies show that NK cells are critical for optimal resistance to T. congolense,and its deficiency leads to enhanced susceptibility in infected mice. View Publication

Glucocorticoids (GCs) play an important role in controlling acute graft-versus-host disease (aGvHD),a frequent complication of allogeneic hematopoietic stem cell transplantation. The anti-inflammatory activity of GCs is mainly ascribed to the modulation of T cells and macrophages,for which reason a genetically induced GC resistance of either of these cell types causes aggravated aGvHD. Since only a few genes are currently known that are differentially regulated under these conditions,we analyzed the expression of 54 candidate genes in the inflamed small intestine of mice suffering from aGvHD when either allogeneic T cells or host myeloid cells were GC resistant using a microfluidic dynamic array platform for high-throughput quantitative PCR. The majority of genes categorized as cytokines (e.g. Il2,Il6),chemokines (e.g. Ccl2,Cxcl1),cell surface receptors (e.g. Fasl,Ctla4) and intracellular molecules (e.g. Dusp1,Arg1) were upregulated in mice transplanted with GC resistant allogeneic T cells. Moreover,the expression of several genes linked to energy metabolism (e.g. Glut1) was altered. Surprisingly,mice harboring GC resistant myeloid cells showed almost no changes in gene expression despite their fatal disease course after aGvHD induction. To identify additional genes in the inflamed small intestine that were affected by a GC resistance of allogeneic T cells,we performed an RNAseq analysis,which uncovered more than 500 differentially expressed transcripts (e.g. Cxcr6,Glut3,Otc,Aoc1,Il1r1,Sphk1) that were enriched for biological processes associated with inflammation and tissue disassembly. The changes in gene expression could be confirmed during full-blown disease but hardly any of them in the preclinical phase using high-throughput quantitative PCR. Further analysis of some of these genes revealed a highly selective expression pattern in T cells,intestinal epithelial cells and macrophages,which correlated with their regulation during disease progression. Collectively,we identified an altered gene expression profile caused by GC resistance of transplanted allogeneic T cells,which could help to define new targets for aGvHD therapy. View Publication