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

Cardiomyocytes (CMs) generated from human pluripotent stem cells (hPSCs) are a potential cell source for regenerative therapies,drug discovery and disease modeling. All these applications require a routine supply of relatively large quantities of in vitro-generated CMs. This protocol describes a suspension culture-based strategy for the generation of hPSC-CMs as cell-only aggregates,which facilitates process development and scale-up. Aggregates are formed for 4 d in hPSC culture medium followed by 10 d of directed differentiation by applying chemical Wnt pathway modulators. The protocol is applicable to static multiwell formats supporting fast adaptation to specific hPSC line requirements. We also demonstrate how to apply the protocol using stirred tank bioreactors at a 100-ml scale,providing a well-controlled upscaling platform for CM production. In bioreactors,the generation of 40-50 million CMs per differentiation batch at textgreater80% purity without further lineage enrichment can been achieved within 24 d. View Publication

Insulin resistance,a critical component of type 2 diabetes (T2D),precedes and predicts T2D onset. T2D is also associated with mitochondrial dysfunction. To define the cause-effect relationship between insulin resistance and mitochondrial dysfunction,we compared mitochondrial metabolism in induced pluripotent stem cells (iPSC) from 5 healthy individuals and 4 patients with genetic insulin resistance due to insulin receptor mutations. Insulin-resistant iPSC had increased mitochondrial number and decreased mitochondrial size. Mitochondrial oxidative function was impaired,with decreased citrate synthase activity and spare respiratory capacity. Simultaneously,expression of multiple glycolytic enzymes was decreased,while lactate production increased 80%. These perturbations were accompanied by an increase in ADP/ATP ratio and 3-fold increase in AMPK activity,indicating energetic stress. Insulin-resistant iPSC also showed reduced catalase activity and increased susceptibility to oxidative stress. Thus,insulin resistance can lead to mitochondrial dysfunction with reduced mitochondrial size,oxidative activity,and energy production. View Publication

Human embryonic stem cells (hESCs) are promising in regenerative medicine (RM) due to their differentiation plasticity and proliferation potential. However,a major challenge in RM is the generation of a vascular system to support nutrient flow to newly synthesized tissues. Here we refined an existing method to generate tight vessels by differentiating hESCs in CD34(+) vascular progenitor cells using chemically defined media and growth conditions. We selectively purified these cells from CD34(-) outgrowth populations also formed. To analyze these differentiation processes,we compared the proteomes of the hESCs with those of the CD34(+) and CD34(-) populations using high resolution mass spectrometry,label-free quantification,and multivariate analysis. Eighteen protein markers validate the differentiated phenotypes in immunological assays; nine of these were also detected by proteomics and show statistically significant differential abundance. Another 225 proteins show differential abundance between the three cell types. Sixty-three of these have known functions in CD34(+) and CD34(-) cells. CD34(+) cells synthesize proteins implicated in endothelial cell differentiation and smooth muscle formation,which support the bipotent phenotype of these progenitor cells. CD34(-) cells are more heterogeneous synthesizing muscular/osteogenic/chondrogenic/adipogenic lineage markers. The remaining textgreater150 differentially abundant proteins in CD34(+) or CD34(-) cells raise testable hypotheses for future studies to probe vascular morphogenesis. View Publication

Pluripotent stem cells (PSCs) can self-renew or differentiate from naive or more differentiated,primed,pluripotent states established by specific culture conditions. Increased intracellular α-ketoglutarate (αKG) was shown to favor self-renewal in naive mouse embryonic stem cells (mESCs). The effect of αKG or αKG/succinate levels on differentiation from primed human PSCs (hPSCs) or mouse epiblast stem cells (EpiSCs) remains unknown. We examined primed hPSCs and EpiSCs and show that increased αKG or αKG-to-succinate ratios accelerate,and elevated succinate levels delay,primed PSC differentiation. αKG has been shown to inhibit the mitochondrial ATP synthase and to regulate epigenome-modifying dioxygenase enzymes. Mitochondrial uncoupling did not impede αKG-accelerated primed PSC differentiation. Instead,αKG induced,and succinate impaired,global histone and DNA demethylation in primed PSCs. The data support αKG promotion of self-renewal or differentiation depending on the pluripotent state. View Publication

The role of NK cells against HIV-1 infections remains to be elucidated in vivo. While humanized mouse models potentially could be used to directly evaluate human NK cell responses during HIV-1 infection,improved functional development of human NK cells in these hosts is needed. Here,we report the humanized MISTRG-6-15 mouse model,in which NK cells were quick to expand and exhibit degranulation,cytotoxicity,and proinflammatory cytokine production in nonlymphoid organs upon HIV-1 infection but had reduced functionality in lymphoid organs. Although HIV-1 infection induced functional impairment of NK cells,antiretroviral therapy reinvigorated NK cells in response to HIV-1 rebound after analytic treatment interruption. Moreover,a broadly neutralizing antibody,PGT121,enhanced NK cell function in vivo,consistent with antibody-dependent cellular cytotoxicity. Monoclonal antibody depletion of NK cells resulted in higher viral loads in multiple nonlymphoid organs. Overall,our results in humanized MISTRG-6-15 mice demonstrated that NK cells provided direct anti-HIV-1 responses in vivo but were limited in their responses in lymphoid organs. View Publication

Toll-like receptors (TLR) recognize pathogen-associated molecular patterns and play important roles in the innate immune system. While single-stranded viral RNA is the natural ligand of TLR7/TLR8,the imidazoquinoline resiquimod (R-848) is recognized as a potent synthetic agonist of TLR7/TLR8. We investigated the effects of TLR7/8 activation on lipid mediator production in polymorphonuclear leukocytes exposed to R-848. Although R-848 had minimal effects by itself,it strongly enhanced leukotriene B4 formation on subsequent stimulation by fMLP,platelet-activating factor,and the ionophore A23187. R-848 acted via TLR8 but not TLR7 as shown by the lack of effect of the TLR7-specific ligand imiquimod. Priming with R-848 also resulted in enhanced arachidonic acid release and platelet-activating factor formation following fMLP stimulation,as well as enhanced prostaglandin E2 synthesis following the addition of arachidonic acid. Western blot analysis demonstrated that R-848 induced the phosphorylation of the cytosolic phospholipase A2alpha,promoted 5-lipoxygenase translocation and potently stimulated the expression of the type 2 cyclooxygenase. Bafilomycin A1,an inhibitor of endosomal acidification,efficiently inhibited all R-848-induced effects. These studies demonstrate that TLR8 signaling strongly promotes inflammatory lipid mediator biosynthesis and provide novel insights on innate immune response to viral infections. View Publication

OBJECTIVE: Bone marrow-derived mononuclear cells (BMCs) improve the functional recovery after ischemia. However,BMCs comprise a heterogeneous mixture of cells,and it is not known which cell types are responsible for the induction of neovascularization after cell therapy. Because cell recruitment is critically dependent on the expression of the SDF-1-receptor CXCR4,we examined whether the expression of CXCR4 may identify a therapeutically active population of BMCs. METHODS AND RESULTS: Human CXCR4(+) and CXCR4(-) BMCs were sorted by magnetic beads. CXCR4(+) BMCs showed a significantly higher invasion capacity under basal conditions and after SDF-1 stimulation. Hematopoietic or mesenchymal colony-forming capacity did not differ between CXCR4(+) and CXCR4(-) BMCs. Injection of CXCR4(+) BMCs in mice after induction of hindlimb ischemia significantly improved the recovery of perfusion compared to injection of CXCR4(-) BMCs. Likewise,capillary density was significantly increased in CXCR4(+) BMC-treated mice. Because part of the beneficial effects of cell therapy were attributed to the release of paracrine effectors,we analyzed BMC supernatants for secreted factors. Importantly,supernatants of CXCR4(+) BMCs were enriched in the proangiogenic cytokines HGF and PDGF-BB. CONCLUSIONS: CXCR4(+) BMCs exhibit an increased therapeutic potential for blood flow recovery after acute ischemia. Mechanistically,their higher migratory capacity and their increased release of paracrine factors may contribute to enhanced tissue repair. View Publication

Human pluripotent stem cells will likely be a significant part of the regenerative medicine-driven healthcare revolution. In order to realize this potential,culture processes must be standardized,scalable and able to produce clinically relevant cell numbers,whilst maintaining critical biological functionality. This review comprises a broad overview of important bioprocess considerations,referencing the development of biopharmaceutical processes in an effort to learn from current best practice in the field. Particular focus is given to the recent efforts to grow human pluripotent stem cells in microcarrier or aggregate suspension culture,which would allow geometric expansion of productive capacity were it to be fully realized. The potential of these approaches is compared with automation of traditional T-flask culture,which may provide a cost-effective platform for low-dose,low-incidence conditions or autologous therapies. This represents the first step in defining the full extent of the challenges facing bioprocess engineers in the exploitation of large-scale human pluripotent stem cell manufacture. View Publication

Pluripotency is a unique state in which cells can self-renew indefinitely but also retain the ability to differentiate into other cell types upon receipt of extracellular cues. Although it is clear that stem cells have a distinct transcriptional program,little is known about how alterations in post-transcriptional mechanisms,such as mRNA turnover,contribute to the achievement and maintenance of pluripotency. Here we have assessed the rates of decay for the majority of mRNAs expressed in induced pluripotent stem (iPS) cells and the fully differentiated human foreskin fibroblasts (HFFs) they were derived from. Comparison of decay rates in the two cell types led to the discovery of three independent regulatory mechanisms that allow coordinated turnover of specific groups of mRNAs. One mechanism results in increased stability of many histone mRNAs in iPS cells. A second pathway stabilizes a large set of zinc finger protein mRNAs,potentially through reduced levels of miRNAs that target them. Finally,a group of transcripts bearing 3' UTR C-rich sequence elements,many of which encode transcription factors,are significantly less stable in iPS cells. Intriguingly,two poly(C)-binding proteins that recognize this type of element are reciprocally expressed in iPS and HFF cells. Overall,our results highlight the importance of post-transcriptional control in pluripotent cells and identify miRNAs and RNA-binding proteins whose activity may coordinately control expression of a wide range of genes in iPS cells. View Publication

Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent antitumor effects in B-cell malignancies including acute lymphoblastic leukemia (ALL),but antigen loss remains the major cause of treatment failure. To mitigate antigen escape and potentially improve the durability of remission,we developed a dual-targeting approach using an optimized,bispecific CAR construct that targets both CD19 and BAFF-R. CD19/BAFF-R dual CAR T cells exhibited antigen-specific cytokine release,degranulation,and cytotoxicity against both CD19-/- and BAFF-R-/- variant human ALL cells in vitro. Immunodeficient mice engrafted with mixed CD19-/- and BAFF-R-/- variant ALL cells and treated with a single dose of CD19/BAFF-R dual CAR T cells experienced complete eradication of both CD19-/- and BAFF-R-/- ALL variants,whereas mice treated with monospecific CD19 or BAFF-R CAR T cells succumbed to outgrowths of CD19-/BAFF-R+ or CD19+/BAFF-R- tumors,respectively. Further,CD19/BAFF-R dual CAR T cells showed prolonged in vivo persistence,raising the possibility that these cells may have the potential to promote durable remissions. Together,our data support clinical translation of BAFF-R/CD19 dual CAR T cells to treat ALL. View Publication

BackgroundChronic ischemic limb disease often leads to amputation,which remains a significant clinical problem. Smooth-muscle cells (SMCs) are crucially involved in the development and progression of many cardiovascular diseases,but studies with primary human SMCs have been limited by a lack of availability. Here,we evaluated the efficiency of two novel protocols for differentiating human induced-pluripotent stem cells (hiPSCs) into SMCs and assessed their potency for the treatment of ischemic limb disease.MethodshiPSCs were differentiated into SMCs via a conventional two-dimensional (2D) protocol that was conducted entirely with cell monolayers,or via two protocols that consisted of an initial five-day three-dimensional (3D) spheroid phase followed by a six-day 2D monolayer phase (3D?+?2D differentiation). The 3D phases were conducted in shaker flasks on an orbital shaker (the 3D?+?2D shaker protocol) or in a PBS bioreactor (the 3D?+?2D bioreactor protocol). Differentiation efficiency was evaluated via the expression of SMC markers (smooth-muscle actin [SMA],smooth muscle protein 22 [SM22],and Calponin-1),and the biological activity of the differentiated hiPSC-SMCs was evaluated via in-vitro assessments of migration (scratch assay),contraction in response to the treatment with a prostaglandin H2 analog (U46619),and tube formation on Geltrex,as well as in-vivo measurements of perfusion (fluorescence angiography) and vessel density in the limbs of mice that were treated with hiPSC-SMCs after experimentally induced hind-limb ischemia (HLI).ResultsBoth 3D?+?2D protocols yielded?>?5.6?×?107 hiPSC-SMCs/differentiation,which was?~?nine-fold more than that produced via 2D differentiation,and flow cytometry analyses confirmed that?>?98% of the 3D?+?2D-differentiated hiPSC-SMCs expressed SMA,?>?81% expressed SM22,and?>?89% expressed Calponin-1. hiPSC-SMCs obtained via the 3D?+?2D shaker protocol also displayed typical SMC-like migratory,contraction,and tube-formation activity in-vitro and significantly improved measurements of perfusion,vessel density,and SMA-positive arterial density in the ischemic limb of mouse HLI model.ConclusionsOur dynamic 3D?+?2D protocols produced an exceptionally high yield of hiPSC-SMCs. Transplantation of these hiPSC-SMCs results in significantly improved recovery of ischemic limb after ischemic injury in mice. View Publication