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

Phosphatidylinositol (PtdIns) 4-kinases catalyze the synthesis of PtdIns-4-P,the immediate precursor of PtdIns-4,5-P2. Here we report the cloning of a novel,ubiquitously expressed PtdIns 4-kinase (PI4Kbeta). The 2.4-kilobase pair cDNA encodes a putative translation product of 801 amino acids which shows greatest homology to the yeast PIK1 gene. The recombinant protein exhibits lipid kinase activity when expressed in Escherichia coli,and specific antibodies recognize a 110-kDa PtdIns 4-kinase in cell lysates. The biochemical properties of PI4Kbeta are characteristic of a type III enzyme. Interestingly,both recombinant PI4Kbeta and the endogenous protein are inhibited by 150 nM wortmannin,suggesting that we have cloned the previously described PtdIns 4-kinase that is responsible for regulating the synthesis of agonist-sensitive pools of polyphosphoinositides (Nakanishi,S.,Catt,J. K.,and Balla,T. (1995) Proc. Natl. Acad. Sci. U. S. A. 92,5317-5321). View Publication

A large number of human embryonic stem cell (hESC) lines have been derived worldwide since the first hESC line establishment in 1998. Despite many common characteristics,most important of which is the pluripotency,hESC lines vary significantly in their transcriptional profiles,genetic,and epigenetic state. These differences may arise both from individual genetics of the cell lines and from variations in their handling such as isolation and cultivation. In order to minimize the latter differences,the standardized protocols of cultivation and inter-laboratory comprehensive studies should be performed. In this report,we summarized our experience of derivation and characterization of hESC lines as well as of adaptation of hESCs to novel cultivation protocols. We have successfully derived five hESC lines and characterized them by previously established criteria,including expression of specific markers and the capacity to differentiate both in vitro and in vivo. Four of these lines,namely hESM01-04,were initially derived using mouse fibroblasts as a feeder and currently are maintained under feeder-free,serum-free conditions using mTeSR1 and Matrigel. The fifth line,hESMK05 was derived in feeder-free,serum-free conditions using mTeSR1 and Matrigel. Cell lines retain their pluripotent status and normal karyotype for more than 70 passages and are available to the scientific community. View Publication

The formation of mammalian synapses entails the precise alignment of presynaptic release sites with postsynaptic receptors but how nascent cell–cell contacts translate into assembly of presynaptic specializations remains unclear. Guided by pioneering work in invertebrates,we hypothesized that in mammalian synapses,liprin-? proteins directly link trans-synaptic initial contacts to downstream steps. Here we show that,in human neurons lacking all four liprin-? isoforms,nascent synaptic contacts are formed but recruitment of active zone components and accumulation of synaptic vesicles is blocked,resulting in ‘empty’ boutons and loss of synaptic transmission. Interactions with presynaptic cell adhesion molecules of either the LAR-RPTP family or neurexins via CASK are required to localize liprin-? to nascent synaptic sites. Liprin-? subsequently recruits presynaptic components via a direct interaction with ELKS proteins. Thus,assembly of human presynaptic terminals is governed by a hierarchical sequence of events in which the recruitment of liprin-? proteins by presynaptic cell adhesion molecules is a critical initial step. This paper identifies the evolutionarily conserved liprin-? protein family as key mediators of presynaptic assembly in human neurons. Their recruitment to sites formed by contacting neurons is the critical initial step that triggers presynaptic differentiation. View Publication

The integrity of the blood–labyrinth barrier (BLB) is essential for inner ear homeostasis,regulating the ionic composition of endolymph and perilymph and preventing harmful substance entry. Endothelial hyperpermeability,central in inflammatory and immune responses,is managed through complex intercellular communication and molecular signaling pathways. Recent studies link BLB permeability dysregulation to auditory pathologies like acoustic trauma,autoimmune inner ear diseases,and presbycusis. Polymorphonuclear granulocytes (PMNs),or neutrophils,significantly modulate vascular permeability,impacting endothelial barrier properties. Neutrophil extracellular traps (NETs) are involved in diseases with autoimmune and autoinflammatory bases. The present study evaluated the impact of NETs on a BLB cellular model using a Transwell® setup. Our findings revealed a concentration-dependent impact of NETs on human inner ear-derived endothelial cells. In particular,endothelial permeability markers increased,as indicated by reduced transepithelial electrical resistance,enhanced dextran permeability,and downregulated junctional gene expression (ZO1,OCL,and CDH5). Changes in cytoskeletal architecture were also observed. These preliminary results pave the way for further research into the potential involvement of NETs in BLB impairment and implications for auditory disorders. View Publication

Kidney organoids are an innovative tool in transplantation research. The aim of the present study was to investigate whether kidney organoids are susceptible for allo-immune attack and whether they can be used as a model to study allo-immunity in kidney transplantation. Human induced pluripotent stem cell-derived kidney organoids were co-cultured with human peripheral blood mononuclear cells (PBMC),which resulted in invasion of allogeneic T-cells around nephron structures and macrophages in the stromal cell compartment of the organoids. This process was associated with the induction of fibrosis. Subcutaneous implantation of kidney organoids in immune-deficient mice followed by adoptive transfer of human PBMC led to the invasion of diverse T-cell subsets. Single cell transcriptomic analysis revealed that stromal cells in the organoids upregulated expression of immune response genes upon immune cell invasion. Moreover,immune regulatory PD-L1 protein was elevated in epithelial cells while genes related to nephron differentiation and function were downregulated. This study characterized the interaction between immune cells and kidney organoids,which will advance the use of kidney organoids for transplantation research. View Publication

CACNA1A encodes the pore-forming α 1A subunit of the Ca V 2.1 calcium channel,whose altered function is associated with various neurological disorders,including forms of ataxia,epilepsy,and migraine. In this study,we generated isogenic iPSC-derived neural cultures carrying CACNA1A loss-of-function mutations differently affecting Ca V 2.1 splice isoforms. Morphological,molecular,and functional analyses revealed an essential role of CACNA1A in neurodevelopmental processes. We found that different CACNA1A loss-of-function mutations produce distinct neurodevelopmental deficits. The F1491S mutation,which is located in a constitutive domain of the channel and therefore causes a complete loss-of-function,impaired neural induction at very early stages,as demonstrated by changes in single-cell transcriptomic signatures of neural progenitors,and by defective polarization of neurons. By contrast,cells carrying the Y1854X mutation,which selectively impacts the synaptically-expressed Ca V 2.1[EFa] isoform,behaved normally in terms of neural induction but showed altered neuronal network composition and lack of synchronized activity. Our findings reveal previously unrecognized roles of CACNA1A in the mechanisms underlying neural induction and neural network dynamics and highlight the differential contribution of the divergent variants Ca V 2.1[EFa] and Ca V 2.1[EFb] in the development of human neuronal cells. The online version contains supplementary material available at 10.1007/s00018-025-05740-7. View Publication

Metformin rejuvenates adult rat oligodendrocyte progenitor cells (OPCs) allowing more efficient differentiation into oligodendrocytes and improved remyelination,and therefore is of interest as a therapeutic in demyelinating diseases such as multiple sclerosis (MS). Here,we test whether metformin has a similar effect in human stem cell derived-OPCs. We assess how well human monoculture,organoid and chimera model culture systems simulate in vivo adult human oligodendrocytes,finding most close resemblance in the chimera model. Metformin increases myelin proteins and/or sheaths in all models even when human cells remain fetal-like. In the chimera model,metformin leads to increased mitochondrial area both in the human transplanted cells and in the mouse axons with associated increase of mitochondrial function/metabolism transcripts. Human oligodendrocytes from MS brain donors treated pre-mortem with metformin also express similar transcripts. Metformin’s brain effect is thus not cell-specific,alters metabolism in part through mitochondrial changes and leads to more myelin production. This bodes well for clinical trials testing metformin for neuroprotection. Subject terms: Oligodendrocyte,Multiple sclerosis,Multiple sclerosis,Regeneration and repair in the nervous system View Publication

The widely varying therapeutic response of patients with inflammatory bowel disease (IBD) continues to raise questions regarding the unclarified heterogeneity of pathological mechanisms promoting disease progression. While biomarkers for the differentiation of Crohn's disease (CD) versus ulcerative colitis (UC) have been suggested,specific markers for a CD subclassification in ileal CD versus colonic CD are still rare. Since an altered signature of the tryptophan metabolism is associated with chronic inflammatory disease,we sought to characterize potential biomarkers by focusing on the downstream enzymes and metabolites of kynurenine metabolism. Using immunohistochemical stainings,we analyzed and compared the mucosal tryptophan immune metabolism in bioptic samples from patients with active inflammation due to UC or CD versus healthy controls. Localization-specific quantification of immune cell infiltration,tryptophan-metabolizing enzyme expression and mucosal tryptophan downstream metabolite levels was performed. We found generally increased immune cell infiltrates in the tissue of all patients with IBD. However,in patients with CD,significant differences were found between regulatory T cell and neutrophil granulocyte infiltration in the ileum compared with the colon. Furthermore,we observed decreased kynurenine levels as well as strong kynureninase (KYNU) expression specifically in patients with ileal CD. Correspondingly,significantly elevated levels of the kynurenine metabolite 3-hydroxyanthranilic acid were detected in the ileal CD samples. Highlighting the heterogeneity of the different phenotypes of CD,we identified KYNU as a potential mucosal biomarker allowing the localization-specific differentiation of ileal CD versus colonic CD. View Publication

Studies with peptide-based and macromolecular inhibitors of the caspase family of cysteine proteases have helped to define a central role for these enzymes in inflammation and mammalian apoptosis. A clear interpretation of these studies has been compromised by an incomplete understanding of the selectivity of these molecules. Here we describe the selectivity of several peptide-based inhibitors and the coxpox serpin CrmA against 10 human caspases. The peptide aldehydes that were examined (Ac-WEHD-CHO,Ac-DEVD-CHO,Ac-YVAD-CHO,t-butoxycarbonyl-IETD-CHO,and t-butoxycarbonyl-AEVD-CHO) included several that contain the optimal tetrapeptide recognition motif for various caspases. These aldehydes display a wide range of selectivities and potencies against these enzymes,with dissociation constants ranging from 75 pM to {\textgreater}10 microM. The halomethyl ketone benzyloxycarbonyl-VAD fluoromethyl ketone is a broad specificity irreversible caspase inhibitor,with second-order inactivation rates that range from 2.9 x 10(2) M-1 s-1 for caspase-2 to 2.8 x 10(5) M-1 s-1 for caspase-1. The results obtained with peptide-based inhibitors are in accord with those predicted from the substrate specificity studies described earlier. The cowpox serpin CrmA is a potent (Ki {\textless} 20 nM) and selective inhibitor of Group I caspases (caspase-1,-4,and -5) and most Group III caspases (caspase-8,-9,and -10),suggesting that this virus facilitates infection through inhibition of both apoptosis and the host inflammatory response. View Publication

The growth of human megakaryocyte progenitors from human bone marrow (BM) cells was compared using a methylcellulose semisolid assay supplemented either by normal human plasma or by a serum-free medium. Far better growth of megakaryocyte colonies from CD34+ BM cells stimulated by interleukin 3 (IL-3) and interleukin 6 (IL-6) was observed in serum-free medium compared with human plasma supplemented cultures. These results were confirmed in liquid cultures using the same serum-free medium composition. The megakaryocytes were identified by using an immunocytochemical procedure after labeling with an anti-GPIIb-IIIa monoclonal antibody. High percentages (15 to 20%) of megakaryocytes were present in serum-free cultures stimulated by IL-3 alone or combined with IL-6. The absolute number of megakaryocytes in serum-free medium exceeds by 3.3 (IL-3 plus IL-6) to 4.4 (IL-3 alone) times the corresponding number of megakaryocytes observed in human plasma supplemented cultures. The optimal concentration of IL-3 alone was 5 ng/ml,and an optimal synergistic effect of IL-6 (5 ng/ml) was obtained when combined with a suboptimal dose of IL-3 (1 ng/ml). The poor growth of megakaryocyte colonies from CD34+ BM cells in human plasma suggested the presence of an inhibitory factor. When a neutralizing monoclonal antibody against transforming growth factor beta (TGF beta) is present in human plasma supplemented cultures of CD34+ BM cells,the number of megakaryocyte colonies is increased to the level observed in corresponding serum-free cultures. The high efficiency of this serum-free medium to promote the growth of human megakaryocytes will be useful to study the effects of regulators and platelet agonists acting on human megakaryocytes,without interference from factors in the serum. View Publication

The translocator protein 18 kDa (TSPO) is a multifunctional outer mitochondrial membrane protein associated with various aspects of mitochondrial physiology and multiple roles in health and disease. Here,we aimed to analyse the role of TSPO in the regulation of mitochondrial and cellular functions in a human neuronal cell model. We used the CRISPR/Cas9 technology and generated TSPO knockout (KO) and control (CTRL) variants of human-induced pluripotent stem cells (hiPSCs). In a multimodal phenotyping approach,we investigated cellular and mitochondrial functions in neural progenitor cells (NPCs),astrocytes,and neurons differentiated from hiPSC CTRL and TSPO KO cell lines. Our analysis revealed reduced mitochondrial respiration and glycolysis,altered Ca2+ levels in the cytosol and mitochondrial matrix,a depolarised MMP,and increased levels of reactive oxygen species,as well as a reduced cell size. Notably,TSPO deficiency was accompanied by reduced expression of the voltage-dependent anion channel (VDAC). We also observed a reduced TSPO and VDAC expression in cells derived from patients suffering from major depressive disorder (MDD). Considering the modulatory function of TSPO and the similar functional phenotype of cells derived from patients with depression,we discuss a role of TSPO in the etiology or pathology of MDD. In summary,our findings indicate a general impairment of mitochondrial function in TSPO knockout (KO) cells. This deepens our insight into the intricate role of TSPO in a range of physiological and pathological processes. View Publication