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

ABSTRACTThe paradoxical exacerbation of cellular injury and death during reperfusion remains a problem in the treatment of myocardial infarction. Mitochondrial dysfunction plays a key role in the pathogenesis of myocardial ischemia and reperfusion injury. Dysfunctional mitochondria can be removed by mitophagy,culminating in their degradation within acidic lysosomes. Mitophagy is pivotal in maintaining cardiac homeostasis and emerges as a potential therapeutic target. Here,we employed beating human engineered heart tissue (EHT) to assess mitochondrial dysfunction and mitophagy during ischemia and reperfusion simulation. Our data indicate adverse ultrastructural changes in mitochondrial morphology and impairment of mitochondrial respiration. Furthermore,our pH-sensitive mitophagy reporter EHTs,generated by a CRISPR/Cas9 endogenous knock-in strategy,revealed induced mitophagy flux in EHTs after ischemia and reperfusion simulation. The induced flux required the activity of the protein kinase ULK1,a member of the core autophagy machinery. Our results demonstrate the applicability of the reporter EHTs for mitophagy assessment in a clinically relevant setting. Deciphering mitophagy in the human heart will facilitate development of novel therapeutic strategies. Summary: Mitochondrial dysfunction and lysosomal degradation of mitochondria (mitophagy) is induced after ischemia and reperfusion simulation in human engineered heart tissue,as shown with an endogenous pH-sensitive mitophagy reporter. View Publication

The cerebellum plays a critical role in all vertebrates,and many neurological disorders are associated with cerebellum dysfunction. A major limitation in cerebellar research has been the lack of adequate disease models. As an alternative to animal models,cerebellar neurons differentiated from pluripotent stem cells have been used. However,previous studies only produced limited amounts of Purkinje cells. Moreover,in vitro generation of Purkinje cells required co-culture systems,which may introduce unknown components to the system. Here we describe a novel differentiation strategy that uses defined medium to generate Purkinje cells,granule cells,interneurons,and deep cerebellar nuclei projection neurons,that self-formed and differentiated into electrically active cells. Using a defined basal medium optimized for neuronal cell culture,we successfully promoted the differentiation of cerebellar precursors without the need for co-culturing. We anticipate that our findings may help developing better models for the study of cerebellar dysfunctions,while providing an advance toward the development of autologous replacement strategies for treating cerebellar degenerative diseases. View Publication

The pulmonary system is comprised of two main compartments,airways and alveolar space. Their tissue and cellular complexity ensure lung function and protection from external agents,for example,virus. Two-dimensional (2D) in vitro systems and animal models have been largely employed to elucidate the molecular mechanisms underlying human lung development,physiology,and pathogenesis. However,neither of these models accurately recapitulate the human lung environment and cellular crosstalk. More recently,human-derived three-dimensional (3D) models have been generated allowing for a deeper understanding of cell-to-cell communication. However,the availability and accessibility of primary human cell sources from which generate the 2D and 3D models may be limited. In the past few years,protocols have been developed to successfully employ human pluripotent stem cells (hPSCs) and differentiate them toward pulmonary fate in vitro. In the present review,we discuss the advantages and pitfalls of hPSC-derived lung 2D and 3D models,including the main characteristics and potentials for these models and their current and future applications for modeling development and diseases. Lung organoids currently represent the closest model to the human pulmonary system. We further focus on the applications of lung organoids for the study of human diseases such as pulmonary fibrosis,infectious diseases,and lung cancer. Finally,we discuss the present limitations and potential future applications of 3D lung organoids. This article is categorized under: Adult Stem Cells,Tissue Renewal,and Regeneration {\textgreater} Stem Cells and Disease Adult Stem Cells,Tissue Renewal,and Regeneration {\textgreater} Stem Cell Differentiation and Reversion. View Publication

Many receptor-linked agents that prime or activate the NADPH oxidase in polymorphonuclear neutrophils (PMNs) elicit changes in cytosolic Ca2+ concentration and activate mitogen-activated protein (MAP) kinases. To investigate the role of Ca2+ in the activation of p38 and p42/44 MAP kinases,we examined the effects of the Ca2+-selective ionophore ionomycin on priming and activation of the PMN oxidase. Ionomycin caused a rapid rise in cytosolic Ca2+ that was due to both a release of cytosolic Ca2+ stores and Ca2+ influx. Ionomycin also activated (2 microM) and primed (20-200 nM) the PMN oxidase. Dual phosphorylation of p38 MAP kinase and phosphorylation of its substrate activating transcription factor-2 were detected at ionomycin concentrations that prime or activate the PMN oxidase,while dual phosphorylation of p42/44 MAP kinase and phosphorylation of its substrate Elk-1 were elicited at 0.2-2 microM. SB-203580,a p38 MAP kinase antagonist,inhibited ionomycin-induced activation of the oxidase (68 +/- 8%,P textless 0.05) and tyrosine phosphorylation of 105- and 72-kDa proteins; conversely,PD-98059,an inhibitor of MAP/extracellular signal-related kinase 1,had no effect. Treatment of PMNs with thapsigargin resulted in priming of the oxidase and activation of p38 MAP kinase. Chelation of cytosolic but not extracellular Ca2+ completely inhibited ionomycin activation of p38 MAP kinase,whereas chelation of extracellular Ca2+ abrogated activation of p42/44 MAP kinase. These results demonstrate the importance of changes in cytosolic Ca2+ for MAP kinase activation in PMNs. View Publication

The fabrication of high-density polymer microarray is described,allowing the simultaneous and efficient evaluation of more than 7000 different polymers in a single-cellular-based screen. These high-density polymer arrays are applied in the search for synthetic substrates for hESCs culture. Up-scaling of the identified hit polymers enables long-term cellular cultivation and promoted successful stem-cell maintenance. View Publication

Chylomicron remnants (CMRs) contribute directly to human monocyte activation in vitro,by increasing reactive oxygen species (ROS) production and cell migration. In this study,the effects of the oxidative state of CMR on the degree of monocyte activation was investigated. CMR-like particles (CRLPs) were prepared in three different oxidative states,normal (CRLPs),protected from oxidation by incorporation of the antioxidant,probucol (pCRLPs),or oxidised with CuSO(4) (oxCRLPs). Lipid accumulation and ROS production were significantly increased in primary human monocytes incubated with CRLPs,whilst secretion on monocyte chemoattractant protein-1 was reduced,but oxCRLPs had no additional effect. In contrast,pCRLPs were taken up by monocytes to a lesser extent and had no significant effect on ROS or MCP-1 secretion. These studies suggest that the oxidative state of CMRs modulates their stimulation of the activation of peripheral blood human monocytes and that dietary antioxidants may provide some protection against these atherogenic effects. View Publication

HUCB (human umbilical cord blood) has been frequently used in clinical allogeneic HSC (haemopoietic stem cell) transplant. However,HUCB is poorly recognized as a rich source of MSC (mesenchymal stem cell). The aim of this study has been to establish a new method for isolating large number of MSC from HUCB to recognize it as a good source of MSC. HUCB samples were collected from women following their elective caesarean section. The new method (Clot Spot method) was carried out by explanting HUCB samples in mesencult complete medium and maintained in 37°C,in a 5% CO2 and air incubator. MSC presence was established by quantitative and qualitative immunophenotyping of cells and using FITC attached to MSC phenotypic markers (CD29,CD73,CD44 and CD105). Haematopoietic antibodies (CD34 and CD45) were used as negative control. MSC differentiation was examined in neurogenic and adipogenic media. Immunocytochemistry was carried out for the embryonic markers: SOX2 (sex determining region Y-box 2),OLIG-4 (oligodendrocyte-4) and FABP-4 (fatty acid binding protein-4). The new method was compared with the conventional Rosset Sep method. MSC cultures using the Clot Spot method showed 3-fold increase in proliferation rate compared with conventional method. Also,the cells showed high expression of MSC markers CD29,CD73,CD44 and CD105,but lacked the expression of specific HSC markers (CD34 and CD45). The isolated MSC showed some differentiation by expressing the neurogenic (SOX2 and Olig4) and adipogenic (FABP-4) markers respectively. In conclusion,HUCB is a good source of MSC using this new technique. View Publication

MYCN amplification without concurrent RB1 mutations characterizes a rare yet highly aggressive subtype of retinoblastoma; however,its precise developmental origins and therapeutic vulnerabilities remain incompletely understood. Here,we modeled this subtype by lentiviral-mediated MYCN overexpression in human pluripotent stem cell-derived retinal organoids,revealing a discrete developmental window (days 70–120) during which retinal progenitors showed heightened susceptibility to transformation. Tumors arising in this period exhibited robust proliferation,expressed SOX2,and lacked CRX,consistent with origin from primitive retinal progenitors. MYCN-overexpressing organoids generated stable cell lines that reproducibly gave rise to MYCN-driven tumors when xenografted into immunodeficient mice. Transcriptomic profiling demonstrated that MYCN-overexpressing organoids closely recapitulated molecular features of patient-derived MYCN-amplified retinoblastomas,particularly through activation of MYC/E2F and mTORC1 signaling pathways. Pharmacological screening further identified distinct therapeutic vulnerabilities,demonstrating distinct subtype-specific sensitivity of MYCN-driven cells to transcriptional inhibitors (THZ1,Flavopiridol) and the cell-cycle inhibitor Volasertib,indicative of a unique oncogene-addicted state compared to RB1-deficient retinoblastoma cells. Collectively,our study elucidates the developmental and molecular mechanisms underpinning MYCN-driven retinoblastoma,establishes a robust and clinically relevant human retinal organoid platform,and highlights targeted transcriptional inhibition as a promising therapeutic approach for this aggressive pediatric cancer subtype. View Publication

Solar ultraviolet (sUV) exposure is known to cause skin damage. However,the pathological mechanisms of sUV on hair follicles have not been extensively explored. Here,we established a model of sUV-exposed skin and its appendages using human induced pluripotent stem cell-derived skin organoids with planar morphology containing hair follicles. Our model closely recapitulated several symptoms of photodamage,including skin barrier disruption,extracellular matrix degradation,and inflammatory response. Specifically,sUV induced structural damage and catagenic transition in hair follicles. As a potential therapeutic agent for hair follicles,we applied exosomes isolated from human umbilical cord blood-derived mesenchymal stem cells to sUV-exposed organoids. As a result,exosomes effectively alleviated inflammatory responses by inhibiting NF-κB activation,thereby suppressing structural damage and promoting hair follicle regeneration. Ultimately,our model provided a valuable platform to mimic skin diseases,particularly those involving hair follicles,and to evaluate the efficacy and underlying mechanisms of potential therapeutics. View Publication

Drugs work by binding to a specific 3D structure on a protein. Drug discovery has historically been driven by prior knowledge of function,either of a protein or chemical. This knowledge of function then drives investigations to probe chemical/protein interactions. We undertook a different approach. We first identified unique 3D structures,agnostic of function,and investigated whether they could lead us to innovative therapeutics. Using a synchrotron-based X-ray source,we first determined high-resolution structures of hundreds of proteins. With a supercomputer running analytical programs created by us,we identified novel 3D structures and screened for chemicals binding them. We then tested their ability to inhibit cancer growth without damaging normal cells. We identified a potent inhibitor of a deadly cancer,melanoma. It was not toxic to normal cells even at 2100-fold higher doses. It worked by inducing anoikis,a fundamental process of known importance for cancer. Therapeutics that selectively induce anoikis are needed. In summary,we demonstrate the power of using a 3D protein structure as the starting point to discover new biology and drugs. Drug discovery historically starts with an established function,either that of compounds or proteins. This can hamper discovery of novel therapeutics. As structure determines function,we hypothesized that unique 3D protein structures constitute primary data that can inform novel discovery. Using a computationally intensive physics-based analytical platform operating at supercomputing speeds,we probed a high-resolution protein X-ray crystallographic library developed by us. For each of the eight identified novel 3D structures,we analyzed binding of sixty million compounds. Top-ranking compounds were acquired and screened for efficacy against breast,prostate,colon,or lung cancer,and for toxicity on normal human bone marrow stem cells,both using eight-day colony formation assays. Effective and non-toxic compounds segregated to two pockets. One compound,Dxr2-017,exhibited selective anti-melanoma activity in the NCI-60 cell line screen. In eight-day assays,Dxr2-017 had an IC50 of 12 nM against melanoma cells,while concentrations over 2100-fold higher had minimal stem cell toxicity. Dxr2-017 induced anoikis,a unique form of programmed cell death in need of targeted therapeutics. Our findings demonstrate proof-of-concept that protein structures represent high-value primary data to support the discovery of novel acting therapeutics. This approach is widely applicable. View Publication

The ε4 isoform of apolipoprotein E (ApoE) is the most significant genetic risk factor for Alzheimer’s disease. Glial cells are the main source of ApoE in the brain,and in microglia,the ε4 isoform of ApoE has been shown to impair mitochondrial metabolism and the uptake of lipids and Aβ42. However,whether the ε4 isoform alters autophagy or lysosomal activity in microglia in basal and inflammatory conditions is unknown. Altogether,microglia-like cells (iMGs) from eight APOE 3/3 and six APOE 4/4 human induced pluripotent stem cell (iPSC) lines were used in this study. The responses of iMGs to Aβ42,LPS and IFNγ were studied by metabolomics,proteomics,and functional assays. Here,we demonstrate that iMGs with the APOE 4/4 genotype exhibit reduced basal pinocytosis levels compared to APOE 3/3 iMGs. Inflammatory stimulation with a combination of LPS and IFNγ or Aβ42 induced PI3K/AKT/mTORC signaling pathway,increased pinocytosis,and blocked autophagic flux,leading to the accumulation of sequestosome 1 (p62) in both APOE 4/4 and APOE 3/3 iMGs. Exposure to Aβ42 furthermore caused lysosomal membrane permeabilization,which was significantly stronger in APOE 4/4 iMGs and positively correlated with the secretion of the proinflammatory chemokine IL-8. Metabolomics analysis indicated a dysregulation in amino acid metabolism,primarily L-glutamine,in APOE 4/4 iMGs. Overall,our results suggest that inflammation-induced metabolic reprogramming places lysosomes under substantial stress. Lysosomal stress is more detrimental in APOE 4/4 microglia,which exhibit endo-lysosomal defects. The online version contains supplementary material available at 10.1186/s12974-025-03470-y. View Publication