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Changes in glycosaminoglycan biosynthesis during differentiation in vitro of human monocytes.

ABSTRACT: Monocytes isolated from human blood were maintained in vitro on plastic culture dishes. After 3-4 days, adherent cells displayed morphological changes previously attributed to differentiation of the cells into histiocytes. 35S-labelled glycosaminoglycans were isolated after incubation of the cells with inorganic [35S]sulphate. Polysaccharide recovered from the culture medium after labelling from day 0 to day 2 or from day 5 to day 7 in vitro was approximately 90% galactosaminoglycan (resistant to deamination by HNO2), irrespective of labelling period. Whereas day-0-2 material was extensively degraded to disaccharide on incubation with the bacterial eliminase chondroitinase AC, a significant portion, about 30%, of the day-5-7 material resisted degradation under the same conditions. The resistant portion was readily depolymerized by treatment with chondroitinase ABC and may be dermatan sulphate. Paper electrophoresis and paper chromatography of the disaccharides obtained by eliminase digestion identified the day-0-2 labelled galactosaminoglycan as chondroitin 4-sulphate. In contrast, the corresponding day-5-7 material yielded approximately 20% disulphated disaccharide, both on digestion with chondroitinase AC and on subsequent enzymic degradation of the chondroitinase AC-resistant fraction. Further treatment of the disulphated disaccharide with chondro-4-sulphatase and chondro-6-sulphatase indicated that both sulphate groups were located on the N-acetylgalactosamine residue. In accordance with these findings, the day-5-7 polysaccharide showed a higher negative charge density than the day-0-2 material on ion-exchange chromatography. It is concluded that the novel properties acquired by the monocyte during prolonged culturing on plastic include the ability to synthesize glycosaminoglycan(s) containing 4,6-disulphated N-acetylgalactosamine units.

SUBMITTER: Kolset SO

PROVIDER: S-EPMC1154275 | biostudies-other | 1983 Mar

REPOSITORIES: biostudies-other

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Project description:BackgroundThe milk-derived protein human Casein alpha s1 (CSN1S1) has recently been detected in blood cells and was shown to possess proinflammatory properties. In the present study, we investigated the effect of CSN1S1 on the differentiation of monocytes.MethodsPrimary human monocytes were stimulated with recombinant CSN1S1 and compared to cells stimulated with GM-CSF/IL-4 or M-CSF/IFNγ. Morphological changes were assessed by microscopy and quantification of surface markers of differentiation by FACS analysis. Phagocytic activity of CSN1S1 stimulated cells was measured by quantification of zymosan labeled particle uptake. The role of mitogen activated protein kinases for CSN1S1-induced differentiation of monocytes and proinflammatory cytokine expression was assessed by supplementation of specific inhibitors.ResultsCSN1S1 at a concentration of 10 μg/ml resulted in morphological changes (irregular shape, pseudopodia) and aggregation of cells, comparable to changes observed in M-CSF/IFNγ differentiated macrophages. Surface marker expression was altered after 24 h with an upregulation of CD14 (mean 2.5 fold) and CD64 (1.9 fold) in CSN1S1 stimulated cells. CSN1S1 treated cells showed a characteristic surface marker pattern for macrophages after 120 h of incubation (CD14high, CD64high, CD83low, CD1alow) comparable to changes observed in M-CSF/IFNγ treated monocytes. Furthermore, phagocytic activity was increased 1.4 and 1.9 fold following stimulation with 10 μg/ml CSN1S1 after 24 and 48 h, respectively. Early GM-CSF, but not GM-CSF/IL-4 induced differentiation of monocytes towards dendritic cells (DC) was inhibited by addition of CSN1S1. Finally, CSN1S1 induced upregulation of CD14 was impeded by inhibition of ERK1/2, while inhibition of the mitogen activated protein kinases JNK and p38 did not influence cellular differentiation. However, JNK and p38 inhibitors impeded CSN1S1 induced secretion of the proinflammatory cytokines IL-1b or IL-6.ConclusionsCSN1S1 skews in vitro differentiation of monocytes towards a macrophage-like phenotype. Data is accumulating that functions of CSN1S1 are beyond nutritional properties and include immunomodulatory effects.

Project description:Objective: It has been demonstrated that the transcription factors TAZ (transcriptional coactivator with PDZ-binding motif), paired box gene 8 (PAX8), and NK2 homeobox 1 (NKX2-1) are coexpressed in the nucleus of thyroid cells. Furthermore, TAZ is known to enhance the transcriptional activity of PAX8 and NKX2-1 as well as the key thyroid-specific gene, thyroglobulin (TG), suggesting a critical role for TAZ in the control of thyroid cell speciation. We previously reported that the small molecule ethacridine, identified as a TAZ activator, was able to induce thyroid-specific transcription in endodermal cells differentiated from human embryonic stem (hES) cells using activin A. Since transcription factors are epigenetically regulated in cell differentiation, we investigated the epigenetic changes in the promoter regions of these key transcription factors during in vitro differentiation of hES cells into thyrocytes. Methods: We initially profiled chromatin accessibility using the technique of Assay for Transposase Accessible Chromatin sequencing (ATAC-seq), and then examined DNA methylation and histone acetylation in the promoter regions of the three selected thyroid transcription factors and the thyroid-specific genes during hES cell differentiation. Results: ATAC-seq analysis showed enriched chromatin accessibility of TAZ, NKX2-1, and PAX8 after exposure to activin A and ethacridine. There were no methylation changes found in the NKX2-1, PAX8, and TAZ promoters by bisulfite sequencing. In contrast, acetylation of histone H4, specifically acetylation of lysine 16, was observed in each of the promoters when measured by chromatin immunoprecipitation polymerase chain reaction assays, which correlated with the activity and expression of NKX2-1 and PAX8 as well as sodium/iodide symporter, thyroid stimulating hormone receptor, and TG genes. Conclusions: These results indicate that ethacridine treatment of activin A-derived endodermal hES cells leads to enhanced chromatin accessibility, which, in turn, allows histone H4 acetylation in the regulation of active genes for speciation of thyroid follicular cells from hES cells.

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Changes in glycosaminoglycan biosynthesis during differentiation in vitro of human monocytes.

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