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

Embryonic stem cells,derived from the inner cell mass of murine blastocysts,can be maintained in a totipotent state in vitro. In appropriate conditions embryonic stem cells have been shown to differentiate in vitro into various derivatives of all three primary germ layers. We describe in this paper conditions to induce differentiation of embryonic stem cells reliably and at high efficiency into adipocytes. A prerequisite is to treat early developing embryonic stem cell-derived embryoid bodies with retinoic acid for a precise period of time. Retinoic acid could not be substituted by adipogenic hormones nor by potent activators of peroxisome proliferator-activated receptors. Treatment with retinoic acid resulted in the subsequent appearance of large clusters of mature adipocytes in embryoid body outgrowths. Lipogenic and lipolytic activities as well as high level expression of adipocyte specific genes could be detected in these cultures. Analysis of expression of potential adipogenic genes,such as peroxisome proliferator-activated receptors gamma and delta and CCAAT/enhancer binding protein beta,during differentiation of retinoic acid-treated embryoid bodies has been performed. The temporal pattern of expression of genes encoding these nuclear factors resembled that found during mouse embryogenesis. The differentiation of embryonic stem cells into adipocytes will provide an invaluable model for the characterisation of the role of genes expressed during the adipocyte development programme and for the identification of new adipogenic regulatory genes. View Publication

Cancer immunotherapy restores or enhances the effector function of CD8+ T cells in the tumour microenvironment1,2. CD8+ T cells activated by cancer immunotherapy clear tumours mainly by inducing cell death through perforin-granzyme and Fas-Fas ligand pathways3,4. Ferroptosis is a form of cell death that differs from apoptosis and results from iron-dependent accumulation of lipid peroxide5,6. Although it has been investigated in vitro7,8,there is emerging evidence that ferroptosis might be implicated in a variety of pathological scenarios9,10. It is unclear whether,and how,ferroptosis is involved in T cell immunity and cancer immunotherapy. Here we show that immunotherapy-activated CD8+ T cells enhance ferroptosis-specific lipid peroxidation in tumour cells,and that increased ferroptosis contributes to the anti-tumour efficacy of immunotherapy. Mechanistically,interferon gamma (IFNgamma) released from CD8+ T cells downregulates the expression of SLC3A2 and SLC7A11,two subunits of the glutamate-cystine antiporter system xc-,impairs the uptake of cystine by tumour cells,and as a consequence,promotes tumour cell lipid peroxidation and ferroptosis. In mouse models,depletion of cystine or cysteine by cyst(e)inase (an engineered enzyme that degrades both cystine and cysteine) in combination with checkpoint blockade synergistically enhanced T cell-mediated anti-tumour immunity and induced ferroptosis in tumour cells. Expression of system xc- was negatively associated,in cancer patients,with CD8+ T cell signature,IFNgamma expression,and patient outcome. Analyses of human transcriptomes before and during nivolumab therapy revealed that clinical benefits correlate with reduced expression of SLC3A2 and increased IFNgamma and CD8. Thus,T cell-promoted tumour ferroptosis is an anti-tumour mechanism,and targeting this pathway in combination with checkpoint blockade is a potential therapeutic approach. View Publication

Pharmacological inhibitors of glycogen synthase kinase-3 (GSK-3) and cyclin-dependent kinases have a promising potential for applications against several neurodegenerative diseases such as Alzheimer's disease. Indirubins,a family of bis-indoles isolated from various natural sources,are potent inhibitors of several kinases,including GSK-3. Using the cocrystal structures of various indirubins with GSK-3beta,CDK2 and CDK5/p25,we have modeled the binding of indirubins within the ATP-binding pocket of these kinases. This modeling approach provided some insight into the molecular basis of indirubins' action and selectivity and allowed us to forecast some improvements of this family of bis-indoles as kinase inhibitors. Predicted molecules,including 6-substituted and 5,6-disubstituted indirubins,were synthesized and evaluated as CDK and GSK-3 inhibitors. Control,kinase-inactive indirubins were obtained by introduction of a methyl substitution on N1. View Publication

Neuropilin-1 (Nrp1) is a multifunctional protein,identified principally as a receptor for the class 3 semaphorins and members of the vascular endothelial growth factor (VEGF) family,but it is capable of other interactions. It is a marker of regulatory T cells (Tr),which often carry Nrp1 and latency-associated peptide (LAP)-TGF-beta1 (the latent form). The signaling TGF-beta1 receptors bind only active TGF-beta1,and we hypothesized that Nrp1 binds the latent form. Indeed,we found that Nrp1 is a high-affinity receptor for latent and active TGF-beta1. Free LAP,LAP-TGF-beta1,and active TGF-beta1 all competed with VEGF165 for binding to Nrp1. LAP has a basic,arginine-rich C-terminal motif similar to VEGF and peptides that bind to the b1 domain of Nrp1. A C-terminal LAP peptide (QSSRHRR) bound to Nrp1 and inhibited the binding of VEGF and LAP-TGF-beta1. We also analyzed the effects of Nrp1/LAP-TGF-beta1 coexpression on T cell function. Compared with Nrp1(-) cells,sorted Nrp1+ T cells had a much greater capacity to capture LAP-TGF-beta1. Sorted Nrp1(-) T cells captured soluble Nrp1-Fc,and this increased their ability to capture LAP-TGF-beta1. Conventional CD4+CD25(-)Nrp1(-) T cells coated with Nrp1-Fc/LAP-TGF-beta1 acquired strong Tr activity. Moreover,LAP-TGF-beta was activated by Nrp1-Fc and also by a peptide of the b2 domain of Nrp1 (RKFK; similar to a thrombospondin-1 peptide). Breast cancer cells,which express Nrp1,also captured and activated LAP-TGF-beta1 in a Nrp1-dependent manner. Thus,Nrp1 is a receptor for TGF-beta1,activates its latent form,and is relevant to Tr activity and tumor biology. View Publication

Elotuzumab is a monoclonal antibody in development for multiple myeloma (MM) that targets CS1,a cell surface glycoprotein expressed on MM cells. In preclinical models,elotuzumab exerts anti-MM efficacy via natural killer (NK)-cell-mediated antibody-dependent cellular cytotoxicity (ADCC). CS1 is also expressed at lower levels on NK cells where it acts as an activating receptor. We hypothesized that elotuzumab may have additional mechanisms of action via ligation of CS1 on NK cells that complement ADCC activity. Herein,we show that elotuzumab appears to induce activation of NK cells by binding to NK cell CS1 which promotes cytotoxicity against CS1(+) MM cells but not against autologous CS1(+) NK cells. Elotuzumab may also promote CS1-CS1 interactions between NK cells and CS1(+) target cells to enhance cytotoxicity in a manner independent of ADCC. NK cell activation appears dependent on differential expression of the signaling intermediary EAT-2 which is present in NK cells but absent in primary,human MM cells. Taken together,these data suggest elotuzumab may enhance NK cell function directly and confer anti-MM efficacy by means beyond ADCC alone. View Publication