Monensin inhibits synthesis of proteoglycan, but not of hyaluronate, in chondrocytes.
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ABSTRACT:
SUBMITTER: Mitchell D
PROVIDER: S-EPMC1158098 | biostudies-other | 1982 Jan
REPOSITORIES: biostudies-other
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Project description:Chondrocytes isolated from larynges of adult pigs were cultured as cell suspensions for at least 4 days before use. During continuous-labelling experiments in nutrient medium for 18h with 35SO42- and [3H]glucosamine as precursors, some macromolecular polyanionic material was synthesized which behaved on gel chromatography as proteoglycan. Gel chromatography on Sepharose 2B showed that a proportion of the proteoglycans in the medium appeared to be aggregated, and was dissociated in 4M-guanidinium chloride. Moreover the dissociated proteoglycan interacted with hyaluronic acid. Newly synthesized proteoglycan was larger than the average total cetylpyridinium chloride-precipitable material assayed as uronic acid alone.
| S-EPMC1164783 | biostudies-other
Project description:The synthesis of link-stabilized proteoglycan aggregates by rabbit articular chondrocytes was investigated by [35S]sulphate labelling of primary monolayer cultures maintained for up to 21 days. (1) At all culture times the cells secreted a high-molecular-weight cartilage-type proteoglycan monomer of which 75%-80% formed aggregates with hyaluronic acid. (2) At 2 days of culture all of the aggregates were in link-stabilized form, but by 21 days only 5% were link-stabilized, as shown by displacement of monomers from the aggregate by hyaluronic acid oligosaccharides. (3) The addition of purified link protein to 21-day culture medium increased the proportion of link-stable aggregate from 5% to 70%. (4) Analysis of [3H]serine-labelled proteoglycan aggregates in the medium showed a marked decrease with culture time in the ratio of 3H-labelled link protein to 3H-labelled core protein present. The results suggest that the secretion of proteoglycan monomers and link protein by articular chondrocytes changes independently during prolonged monolayer culture.
| S-EPMC1152324 | biostudies-other
Project description:1. Cyclofenil diphenol (F6060), a weak non-steroidal oestrogen, was shown previously to inhibit [35S]proteoglycan synthesis [Mason, Lineham, Phillipson & Black (1984) Biochem. J. 223, 401-412] and to induce fragmentation of the Golgi apparatus into small vesicles [Lancaster, Fryer, Griffiths & Mason (1989) J. Cell Sci. 92, 271-280] in cultures of Swarm chondrosarcoma chondrocytes. Two structurally related compounds, F6204 and F6091, show a similar concentration-related effect, with complete inhibition of [35S]proteoglycan synthesis at 90 micrograms/ml. The apparent [3H]protein synthesis is only approx. 40% inhibited with [3H]lysine as precursor. Stilboestrol, clomiphene and tamoxiphen are also potent inhibitors of [35S]proteoglycan synthesis. 2. Syntheses of chondroitin 4-[35S]sulphate and chondroitin 6-[35S]sulphate, which are Golgi-mediated events, are inhibited 40-68% and 3-48% respectively by concentrations of cyclofenil between 50 and 70 micrograms/ml. [3H]Hyaluronan synthesis, which occurs by a different mechanism at the plasma membrane, is inhibited by 47-66%. These results suggest that cyclofenil may act via more than one inhibitory mechanism. Cyclofenil diphenol inhibits polymerization of chondroitin sulphate on to p-nitrophenyl beta-xyloside even when the chondrocytes are loaded with the initiator prior to treatment. 3. Cyclofenil diphenol interferes with the cellular uptake of amino acids via the system A carrier, as shown by inhibition of uptake of methylaminoisobutyric acid, a specific substrate for this system. The drug had no effect on the uptake of 2-deoxyglucose by the cells. 4. Cyclofenil diphenol (90 micrograms/ml) caused a decrease in the pool size of UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine and UDP-hexoses, but this was insufficient to account for the accompanying profound inhibition of [35S]proteoglycan synthesis. Entry of [3H]glucosamine into the cell and into the UDP-N-acetylhexosamine pool did not appear to be affected. 5. Cyclofenil diphenol inhibited the substitution of 3H-labelled proteoglycan core protein with chondroitin sulphate chains. Core protein was identified in treated cultures on the basis of immunoprecipitation with an antiserum against the hyaluronate-binding region and distinguished from precipitated proteoglycan on SDS/PAGE.
| S-EPMC1130717 | biostudies-other
Project description:Cyclofenil diphenol, a weak non-steroidal oestrogen, binds to albumin. In the presence of concentrations of albumin just sufficient to keep cyclofenil diphenol in solution, the compound inhibited the synthesis of [35S]proteoglycans, [3H]glycoproteins, [3H]hyaluronate and [3H]proteins in primary cultures of chondrocytes from the Swarm rat chondrosarcoma in a dose-dependent manner. When excess albumin was present, conditions were found (90 micrograms of cyclofenil diphenol and 4 mg of albumin per ml of culture medium) which completely inhibited [35S]proteoglycan and [3H]hyaluronate synthesis but had little effect on [3H]protein or [3H]glycoprotein synthesis. The time of onset of inhibition of [35S]proteoglycan synthesis by cyclofenil diphenol was very rapid (t1/2 less than 25 min) and incompatible with an action mediated through suppression of proteoglycan core protein synthesis. Cyclofenil diphenol inhibited the synthesis of [35S]chondroitin sulphate chains onto p-nitrophenyl beta-D-xyloside in the cultures. Cyclofenil diphenol had little effect on the secretion from chondrocytes of [35S]proteoglycans synthesized immediately prior to treatment. Chondrocyte cultures treated with cyclofenil diphenol recovered their biosynthetic activities almost completely within 3 h of removing the compound from the culture medium. Cyclofenil diphenol had a similar inhibitory action on the synthesis of [35S]proteoglycans in secondary cultures of human dermal fibroblasts from both normal subjects and patients with systemic sclerosis. It is proposed that cyclofenil diphenol inhibits the synthesis of [35S]proteoglycans by interfering with the formation of the glycosaminoglycan side chains of these molecules in the Golgi apparatus of cells. The action may be due to disturbance of Golgi membrane organization by the compound.
| S-EPMC1144312 | biostudies-other
Project description:UDP-GlcNAc (UDP-N-acetylglucosamine) and UDP-GlcA (UDP-glucuronic acid) were oxidized by periodate in the ribose ring and utilized as inhibitors for hyaluronate synthase in membrane fractions from the B6 cell line and in cell cultures of B6 cells and human fibrosarcoma HT 1080. Inhibition was irreversible and concentration-dependent and could be prevented in the case of periodate-oxidized UDP-GlcNAc by UDP-GlcNAc. Periodate-oxidized UDP-GlcNAc was shown to block chain elongation of hyaluronate. Introduction of periodate-oxidized UDP-GlcA into B6 cells by hypo-osmotic lysis of pinocytotic vesicles decreased hyaluronate synthesis by direct inhibition of the synthase. In HT 1080 cells the synthesis of hyaluronate, chondroitin sulphate and heparan sulphate was inhibited simultaneously.
| S-EPMC1144646 | biostudies-other
Project description:Apples are well known to have various benefits for the human body. Procyanidins are a class of polyphenols found in apples that have demonstrated effects on the circulatory system and skeletal organs. Osteoarthritis (OA) is a locomotive syndrome that is histologically characterized by cartilage degeneration associated with the impairment of proteoglycan homeostasis in chondrocytes. However, no useful therapy for cartilage degeneration has been developed to date. In the present study, we detected beneficial effects of apple polyphenols or their procyanidins on cartilage homeostasis. An in vitro assay revealed that apple polyphenols increased the activities of mitochondrial dehydrogenases associated with an increased copy number of mitochondrial DNA as well as the gene expression of peroxisome proliferator-activated receptor gamma coactivator 1-? (PGC-1?), suggesting the promotion of PGC-1?-mediated mitochondrial biogenesis. Apple procyanidins also enhanced proteoglycan biosynthesis with aggrecan upregulation in primary chondrocytes. Of note, oral treatment with apple procyanidins prevented articular cartilage degradation in OA model mice induced by mitochondrial dysfunction in chondrocytes. Our findings suggest that apple procyanidins are promising food components that inhibit OA progression by promoting mitochondrial biogenesis and proteoglycan homeostasis in chondrocytes.
| S-EPMC5940809 | biostudies-other
Project description:The expression of six cell-surface proteoglycans (syndecan, fibroglycan, amphiglycan, glypican, betaglycan and CD44) was studied at the mRNA level. Analysis was performed by Northern blotting using total RNA preparations from freshly isolated articular chondrocytes obtained from both juveniles and adults. Similar results were obtained for both age groups. By far the most abundant message was that for amphiglycan, CD44 message was next in relative abundance, and the messages for fibroglycan, glypican and betaglycan were all expressed at low levels. Syndecan message could not be detected by this technique. This pattern of expression was different to that observed in cultured skin fibroblasts, where the messages for amphiglycan, CD44, fibroglycan and glypican were all expressed at a similar level. In contrast with the fibroblasts, where the amphiglycan message exhibits no size polymorphism, the chondrocyte amphiglycan message is present in three polymorphic forms, due to the use of alternative polyadenylation signals. When the newly isolated chondrocytes are maintained in monolayer culture for several passages, the amphiglycan message heterogeneity reverts to that characteristic of the fibroblasts. Thus human articular chondrocytes are characterized by both their high level of amphiglycan message expression and their use of alternative polyadenylation signals.
| S-EPMC1135725 | biostudies-other
Project description:BackgroundSphingosine-1-phosphate (S1P), a downstream metabolite of ceramide, induces various bioactivities via two distinct pathways: as an intracellular second messenger or through receptor activation. The receptor for S1P (S1PR) is the family of Endothelial differentiation, sphingolipid G-protein-coupled receptor (EDG). We have here attempted to reveal the expression of EDG/S1PR in human articular chondrocytes (HAC), exploring the implications of S1P in cartilage degradation.MethodsArticular cartilage specimens were obtained from patients with rheumatoid arthritis (RA), osteoarthritis (OA) or traumatic fracture (representing normal chondrocytes) who underwent joint surgery. Isolated HAC were cultured in vitro by monolayer and stimulated with S1P in the presence or absence of inhibitors of signaling molecules. Stimulated cells and culture supernatants were collected and subjected to analyses using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA).ResultsAll of the tested HAC samples showed positive results in terms of EDG/S1PR expression in basal condition. When HAC was stimulated with S1P, a significant increase in prostaglandin (PG) E2 production was observed together with enhanced expression of cyclooxygenase (COX)-2. S1P stimulated extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in HAC, and the PGE2 induction was abrogated by PD98059 and SB203580. Pertussis toxin inhibited the PGE2 induction from HAC by S1P, suggesting an essential role for Gi protein. S1P also attenuated the expression of proteoglycan aggrecan, a component of cartilage matrix, in HAC at transcriptional level.ConclusionIt was suggested that the S1P-induced PGE2 was at least in part involved in the aggrecan-suppressing effect of S1P, seeing as COX inhibitors attenuated the effect. Accordingly, S1P might play an important role in cartilage degradation in arthritides.
| S-EPMC1847513 | biostudies-literature
Project description:Hydrocortisone (HC) and triiodothyronine (T3) have both been shown to be capable of independently inhibiting hyaluronate (HA, hyaluronic acid) synthesis in a self-assembled human dermal equivalent (human dermal matrix). We sought to investigate the action of these two hormones in concert on extracellular matrix formation and HA inhibition in a tissue engineered human dermal matrix.
2015-04-08 | GSE56616 | GEO
Project description:Synthesis of [3H]hyaluronate from [6-3H]glucosamine was investigated in cultures of Swarm rat chondrosarcoma chondrocytes treated with various concentrations (0.1 microM-0.1 mM) of cycloheximide for various times. Concentrations greater than 1 microM inhibited protein synthesis by greater than 90%. Hyaluronate synthesis was decreased, with a t1/2 for 50% inhibition of 80-120 min, depending on the concentration of cycloheximide present. Similar experiments using [1-3H]glucose as a precursor label gave similar results. Experiments using [6-3H]glucosamine as a precursor label and 0.18 mM-puromycin to inhibit protein synthesis inhibited hyaluronate synthesis (t1/2 = 82 min) with similar kinetics to cycloheximide-induced inhibition. Cultures incubated with 3.6 microM-cycloheximide for up to 9 h and supplemented with p-nitrophenyl beta-D-xyloside during the last 75 min of treatment showed increased synthesis of [3H,35S]chondroitin sulphate, demonstrating that UDP-hexose precursors for glycosaminoglycan synthesis are not rapidly depleted on blockage of protein synthesis. Rapid metabolic turnover of hyaluronate synthetase is the most likely cause for decreased hyaluronate synthesis in chondrocytes in which protein synthesis is inhibited.
| S-EPMC1146870 | biostudies-other