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

The transcription factor REST is a key suppressor of neuronal genes in non-neuronal tissues. REST has been shown to suppress proneuronal microRNAs in neural progenitors indicating that REST-mediated neurogenic suppression may act in part via microRNAs. We used neural differentiation of Rest-null mouse ESC to identify dozens of microRNAs regulated by REST during neural development. One of the identified microRNAs,miR-375,was upregulated during human spinal motor neuron development. We found that miR-375 facilitates spinal motor neurogenesis by targeting the cyclin kinase CCND2 and the transcription factor PAX6. Additionally,miR-375 inhibits the tumor suppressor p53 and protects neurons from apoptosis in response to DNA damage. Interestingly,motor neurons derived from a spinal muscular atrophy patient displayed depressed miR-375 expression and elevated p53 protein levels. Importantly,SMA motor neurons were significantly more susceptible to DNA damage induced apoptosis suggesting that miR-375 may play a protective role in motor neurons. View Publication

Appropriate culture methods for the interrogation of primary leukemic samples were hitherto lacking and current assays for compound screening are not adapted for large-scale investigation of synergistic combinations. In this study,we report a novel approach that efficiently distills synthetic lethal interactions between small molecules active on primary human acute myeloid leukemia (AML) specimens. In single-dose experiments and under culture conditions preserving leukemia stem cell activity,our strategy considerably reduces the number of tests needed for the identification of promising compound combinations. Initially conducted with a selected library of 5000 small molecules and 20 primary AML specimens,it reveals 5 broad classes of sensitized therapeutic target pathways along with their synergistic patient-specific fingerprints. This novel method opens new avenues for the development of AML personalized therapeutics and may be generalized to other tumor types,for which in vitro cancer stem cell cultures have been developed. View Publication

Ion channels and transporters have increasingly recognized roles in cancer progression through the regulation of cell proliferation,migration,and death. Glioblastoma stem-like cells (GSCs) are a source of tumor formation and recurrence in glioblastoma multiforme,a highly aggressive brain cancer,suggesting that ion channel expression may be perturbed in this population. However,little is known about the expression and functional relevance of ion channels that may contribute to GSC malignancy. Using RNA sequencing,we assessed the enrichment of ion channels in GSC isolates and non-tumor neural cell types. We identified a unique set of GSC-enriched ion channels using differential expression analysis that is also associated with distinct gene mutation signatures. In support of potential clinical relevance,expression of selected GSC-enriched ion channels evaluated in human glioblastoma databases of The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project correlated with patient survival times. Finally,genetic knockdown as well as pharmacological inhibition of individual or classes of GSC-enriched ion channels constrained growth of GSCs compared to normal neural stem cells. This first-in-kind global examination characterizes ion channels enriched in GSCs and explores their potential clinical relevance to glioblastoma molecular subtypes,gene mutations,survival outcomes,regional tumor expression,and experimental responses to loss-of-function. Together,the data support the potential biological and therapeutic impact of ion channels on GSC malignancy and provide strong rationale for further examination of their mechanistic and therapeutic importance. View Publication

iPSC-derived cells (from induced pluripotent stem cells) are a useful source that provide a powerful and widely accepted tool for the study of various types of human cells in vitro. Indeed,iPSC-derived cells from patients with hereditary diseases have been shown to reproduce the hallmarks of these diseases in vitro,phenotypes that can then also be manipulated in vitro. Quantitative reverse transcription PCR (qRT-PCR) is often used to characterize the progress of iPSC differentiation,validate mature cell types and to determine levels of pathological markers. Quantitative reverse transcription PCR (qRT-PCR) is used to quantify mRNA levels. This method requires some way of normalizing the data,typically by relating the obtained levels of gene expression to the levels of expression of a house keeping gene" View Publication

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor,with dismal survival outcomes. Recently,cancer stem cells (CSCs) have been demonstrated to play a role in therapeutic resistance and are considered to be the most likely cause of cancer relapse. The identification of CSCs is an important step toward finding new and effective ways to treat GBM. Tenascin-C (TNC) protein has been identified as a potential marker for CSCs in gliomas based on previous work. Here,we have investigated the expression of TNC in tissue microarrays including 17 GBMs,18 WHO grade III astrocytomas,15 WHO grade II astrocytomas,4 WHO grade I astrocytomas,and 7 normal brain tissue samples by immunohistochemical staining. TNC expression was found to be highly associated with the grade of astrocytoma. It has a high expression level in most of the grade III astrocytomas and GBMs analyzed and a very low expression in most grade II astrocytomas,whereas it is undetectable in grade I astrocytomas and normal brain tissues. Double-immunofluorescence staining for TNC and CD133 in GBM tissues revealed that there was a high overlap between theses two positive populations. The results were further confirmed by flow cytometry analysis of TNC and CD133 in GBM-derived stem-like neurospheres in vitro. A limiting dilution assay demonstrated that the sphere formation ability of CD133(+)/TNC(+) and CD133(-)/TNC(+) cell populations is much higher than that of the CD133(+)/TNC(-) and CD133(-)/TNC(-) populations. These results suggest that TNC is not only a potential prognostic marker for GBM but also a potential marker for glioma CSCs,where the TNC(+) population is identified as a CSC population overlapping with part of the CD133(-) cell population. View Publication

Aim: Reprogramming of somatic cells utilizing viral free methods provide a remarkable method to generate human induced pluripotent stem cells (hiPSCs) for regenerative medicine. In this study,we evaluate developmental ontogeny of cardiomyocytes following induced differentiation of hiPSCs. Main Methods: Fibroblasts were reprogrammed with episomal vectors to generate hiPSC and were subsequently differentiated to cardiomyocytes. Ontogenic development of cardiomyocytes was studied by real-time PCR. Key findings: Human iPSCs derived from episomal based vectors maintain classical pluripotency markers,generate teratomas and spontaneously differentiate into three germ layers in vitro. Cardiomyogenic induction of these hiPSCs efficiently generated cardiomyocytes. Ontogenic gene expression studies demonstrated that differentiation of cardiomyocytes was initiated by increased expression of mesodermal markers,followed by early cardiac committed markers,structural and ion channel genes. Furthermore,our correlation analysis of gene expression studies with human heart demonstrated that pivotal structural genes like cardiac troponin,actinin,myosin light chain maintained a high correlation with ion channel genes indicating coordinated activation of cardiac transcriptional machinery. Finally,microelectrode recordings show that these cardiomyocytes could respond aptly to pharmacologically active drugs. Cardiomyocytes showed a chronotropic response to isoproterenol,reduced Na+ influx with quinidine,prolongation of beating rate corrected field potential duration (cFPD) with E-4031 and reduced beating frequency and shortened cFPD with verapamil. Significance: Our study shows that viral free hiPSCs efficiently differentiate into cardiomyocytes with cardiac-specific molecular,structural,and functional properties that recapitulate developmental ontogeny of cardiogenesis. These results,coupled with the potential to generate patient-specific hiPSC lines hold great promise for the development of in vitro platform for drug pharmacogenomics; disease modeling and regenerative medicine. textcopyright 2012 Elsevier Inc. All rights reserved. View Publication

Electrospun poly-l-lactic acid (PLLA) nanofiber mats carrying surface amine groups,previously introduced by nitrogen atmospheric pressure nonequilibrium plasma,are embedded into aqueous solutions of oligomeric acrylamide-end capped AGMA1,a biocompatible polyamidoamine with arg-gly-asp (RGD)-reminiscent repeating units. The resultant mixture is finally cured giving PLLA-AGMA1 hydrogel composites that absorb large amounts of water and,in the swollen state,are translucent,soft,and pliable,yet as strong as the parent PLLA mat. They do not split apart from each other when swollen in water and remain highly flexible and resistant,since the hydrogel portion is covalently grafted onto the PLLA nanofibers via the addition reaction of the surface amine groups to a part of the terminal acrylic double bonds of AGMA1 oligomers. Preliminary tested as scaffolds,the composites prove capable of maintaining short-term undifferentiated cultures of human pluripotent stem cells in feeder-free conditions. View Publication

We investigated roles for chemoattractants in dissemination of HIV-1 by examining the induction of T cell-active chemokines in HIV-1-infected human monocyte-derived macrophages and dendritic cells. Of the 12 chemokines analyzed,mRNAs for two,CXCL10 and CXCL11,ligands for the chemokine receptor CXCR3,were up-regulated in both cell types upon infection by HIV-1. Induction of these chemokine genes in infected cultures was dependent on both viral entry and reverse transcriptase activity,but not on the HIV-1 envelope glycoprotein. Conditioned medium from infected cells was chemotactic for freshly isolated human CD4+ T cells,and chemotaxis was abolished by pretreatment with an Ab against CXCR3. A lymph node from an HIV-1-infected individual expressed CXCL10 and CXCL11 mRNAs in the paracortex,including venules,as detected by in situ hybridization,whereas neither mRNA was detected after highly active antiretroviral therapy. Because CCR5 on CD4+ T cells is found predominantly on cells that also express CXCR3,these data implicate CXCL10 and CXCL11 in the recruitment of susceptible T cells to HIV-1-infected lymph nodes,macrophages,and dendritic cells. This recruitment might enhance the sequestration of T cells in infected lymphoid organs and the spread of infection between cells,contributing to the immunopathology of AIDS. View Publication

Genome editing with engineered site-specific endonucleases involves nonhomologous end-joining,leading to reading frame disruption. The approach is applicable to dominant negative disorders,which can be treated simply by knocking out the mutant allele,while leaving the normal allele intact. We applied this strategy to dominant dystrophic epidermolysis bullosa (DDEB),which is caused by a dominant negative mutation in the COL7A1 gene encoding type VII collagen (COL7). We performed genome editing with TALENs and CRISPR/Cas9 targeting the mutation,c.80688084delinsGA. We then cotransfected Cas9 and guide RNA expression vectors expressed with GFP and DsRed,respectively,into induced pluripotent stem cells (iPSCs) generated from DDEB fibroblasts. After sorting,90% of the iPSCs were edited,and we selected four gene-edited iPSC lines for further study. These iPSCs were differentiated into keratinocytes and fibroblasts secreting COL7. RT-PCR and Western blot analyses revealed gene-edited COL7 with frameshift mutations degraded at the protein level. In addition,we confirmed that the gene-edited truncated COL7 could neither associate with normal COL7 nor undergo triple helix formation. Our data establish the feasibility of mutation site-specific genome editing in dominant negative disorders. View Publication

BACKGROUND Chimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA) on multiple myeloma (MM) produces fast but not long-lasting responses. Reasons for treatment failure are poorly understood. CARs simultaneously targeting two antigens may represent an alternative. Here,we (1) designed and characterized novel A proliferation inducing ligand (APRIL) based dual-antigen targeting CARs,and (2) investigated mechanisms of resistance to CAR T cells with three different BCMA-binding moieties (APRIL,single-chain-variable-fragment,heavy-chain-only). METHODS Three new APRIL-CARs were designed and characterized. Human APRIL-CAR T cells were evaluated for their cytotoxic function in vitro and in vivo,for their polyfunctionality,immune synapse formation,memory,exhaustion phenotype and tonic signaling activity. To investigate resistance mechanisms,we analyzed BCMA levels and cellular localization and quantified CAR T cell-target cell interactions by live microscopy. Impact on pathway activation and tumor cell proliferation was assessed in vitro and in vivo. RESULTS APRIL-CAR T cells in a trimeric ligand binding conformation conferred fast but not sustained antitumor responses in vivo in mouse xenograft models. In vitro trimer-BB$\zeta$ CAR T cells were more polyfunctional and formed stronger immune synapses than monomer-BB$\zeta$ CAR T cells. After CAR T cell-myeloma cell contact,BCMA was rapidly downmodulated on target cells with all evaluated binding moieties. CAR T cells acquired BCMA by trogocytosis,and BCMA on MM cells was rapidly internalized. Since BCMA can be re-expressed during progression and persisting CAR T cells may not protect patients from relapse,we investigated whether non-functional CAR T cells play a role in tumor progression. While CAR T cell-MM cell interactions activated BCMA pathway,we did not find enhanced tumor growth in vitro or in vivo. CONCLUSION Antitumor responses with APRIL-CAR T cells were fast but not sustained. Rapid BCMA downmodulation occurred independently of whether an APRIL or antibody-based binding moiety was used. BCMA internalization mostly contributed to this effect,but trogocytosis by CAR T cells was also observed. Our study sheds light on the mechanisms underlying CAR T cell failure in MM when targeting BCMA and can inform the development of improved treatment strategies. View Publication

Recent studies support the notion that there is an intricate relationship between hematopoiesis and bone homeostasis in normal steady states. Using mice undergoing chronic inflammatory arthritis,we investigated the relationship between hematopoiesis and bone homeostasis in pathologic conditions. We demonstrate that mice undergoing chronic inflammatory arthritis displayed osteoporosis resulting from a severe defect in osteoblast function. Despite the defective osteoblast function,however,the hematopoietic stem cells from these mice exhibited normal properties in either long-term repopulation or cell cycling. Therefore,the bone-forming capacity of osteoblasts is distinct from their ability to maintain hematopoietic stem cells in chronic inflammatory conditions. View Publication

BACKGROUND The incidence of neurological complications and fatalities associated with Hand,Foot & Mouth disease has increased over recent years,due to emergence of newly-evolved strains of Enterovirus 71 (EV71). In the search for new antiviral therapeutics against EV71,accurate and sensitive in vitro cellular models for preliminary studies of EV71 pathogenesis is an essential prerequisite,before progressing to expensive and time-consuming live animal studies and clinical trials. METHODS This study thus investigated whether neural lineages derived from pluripotent human embryonic stem cells (hESC) can fulfil this purpose. EV71 infection of hESC-derived neural stem cells (NSC) and mature neurons (MN) was carried out in vitro,in comparison with RD and SH-SY5Y cell lines. RESULTS Upon assessment of post-infection survivability and EV71 production by the various types,it was observed that NSC were significantly more susceptible to EV71 infection compared to MN,RD (rhabdomyosarcoma) and SH-SY5Y cells,which was consistent with previous studies on mice. The SP81 peptide had significantly greater inhibitory effect on EV71 production by NSC and MN compared to the cancer-derived RD and SH-SY5Y cell lines. CONCLUSIONS Hence,this study demonstrates that hESC-derived neural lineages can be utilized as in vitro models for studying EV71 pathogenesis and for screening of antiviral therapeutics. View Publication