Characterization of growth factors in human cartilage

Bekoff, Marjorie C.; Klagsbrun, Michael

doi:10.1002/jcb.240200304

Cited by 16 publications

(2 citation statements)

References 15 publications

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“…In this respect, it was of interest to determine whether TGF-P can also influence the proliferation of articular chondrocytes. So far, the factors that regulate this proliferative activity have not been defined, although several local autocrine or paracrine growth factors have been discovered in cartilage (Beckoff and Klagsbrun, 1982;Kato et al, 1983). To test the hypothesis that TGF-P can regulate chondrocyte growth in vitro, we studied its effects on the proliferation rate of cultured rabbit articular chondrocytes and compared them to the action of epidermal growth factor (EGF) as a nontransforming and typical growth factor.…”

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confidence: 99%

Differential effects of transforming growth factor‐β and epidermal growth factor on the cell cycle of cultured rabbit articular chondrocytes

Vivien

Galéra

Lebrun

et al. 1990

Journal Cellular Physiology

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We examined the effect of transforming growth factor (TGF-beta) on the proliferative rate and cell cycle of cultured rabbit articular chondrocytes using cell counting, cytofluorometry, and [3H]-thymidine incorporation. In the presence of 2% or 10% FCS (fetal calf serum), TGF-beta at 0.01, 0.1, 1, and 10 ng/ml had an inhibitory effect on cell proliferation after 24 h exposure with a dose dependence only for 2% FCS. Flow cytometric analysis of cell DNA content at that time showed that a high proportion of cells were arrested in late S-phase (SQ or G2Q) in either 2% or 10% FCS-containing medium. In both cases, a disappearance of the cell blockage occurred between 24 and 48 h after TGF-beta addition. However, whereas a stimulation of cell proliferation rate was observed at that time in cultures containing 10% FCS, a dose-dependence inhibition of cell growth was detected, in contrast, for 2% FCS-treated cells. Presence of TGF-beta during the last 24 h was not necessary to release the arrested cells. Furthermore, platelet-poor plasma at 10% produced the same effects as FCS, suggesting that platelet-derived factors, such as platelet-derived growth factor (PDGF), could not be responsible for the release of blocked cells in this case. We compared the effect of TGF-beta to that of epidermal growth factor (EGF), used at an optimal concentration (10 ng/ml). In both slowly growing (2% FCS) and proliferating chondrocytes (10% FCS), EGF caused a significant increase of cell proliferation as early as 24 h. No arrest in late S-phase but an augmentation of the percentage of cells in S- and G2M-phases were observed. When combined, TGF-beta and EGF did not induce synergistic effect on the chondrocyte proliferation, as estimated by cell counting. [3H]-thymidine labeling showed that the factors induced identical maxima of incorporation but the peak occurred earlier for TGF-beta than for EGF (approximately 6 h versus 12 h, respectively). Although both factors induce similar cell-number increases at 48 h in 10% FCS-containing medium, these proliferative effects were due to different actions on the cell cycle. The present study indicates that TGF-beta induces first a recruitment of chondrocytes in noncycling SQ- or G2Q-blocked cells. The, the release of these cells may produce either apparent stimulation of cell proliferation if sufficient levels of an unknown serum factor are present (10% FCS) or an inhibition of growth rate when only reduced amounts of this factor are available (2% FCS).(ABSTRACT TRUNCATED AT 400 WORDS)

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mentioning

confidence: 99%

Differential effects of transforming growth factor‐β and epidermal growth factor on the cell cycle of cultured rabbit articular chondrocytes

Vivien

Galéra

Lebrun

et al. 1990

Journal Cellular Physiology

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“…This is likely to contribute to an autocrine/paracrine .control of chondrocyte mitogenesis since cells expressed abundant mRNA encoding one of the high affinity FGF receptors, fZg (Lee et al, 1989), and the basal DNA synthetic rate of the cells was significantly reduced by the biological neutralization of the released basic FGF with a specific blocking antibody. The presence of a cationic growth factor with isoelectric point between 9 and 10, and molecular weight approximately 17 kDa was previously recorded within bovine articular and human costal cartilage by Azizkhan and Klagsbrun (1980) and Bekoff and Klagsbrun (1982). These studies were confirmed and the isolated peptide called 'cartilage-derived growth factor' (Sullivan and Klagsbrun, 1985) which was subsequently shown to be identical to basic FGF with a PI of 9.8 and a molecular weight of 18 kDa (Lobb et al, 1986;Too et al, 1987; Gospodarow- icz , 1989).…”

Section: Discussionmentioning

confidence: 99%

Basic Fibroblast Growth Factor is Synthesized and Released by Isolated Ovine Fetal Growth Plate Chondrocytes: Potential Role as an Autocrine Mitogen

et al. 1992

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Basic fibroblast growth factor (basic FGF) is a mitogen for isolated epiphyseal growth plate chondrocytes. To determine whether basic FGF might function as an autocrine stimulus to longitudinal skeletal growth in utero, we investigated the synthesis and release of basic FGF by isolated growth plate chondrocytes from the ovine fetus, the expression of mRNA for a high affinity basic FGF receptor by these cells, and the contribution of endogenous basic FGF to the DNA synthetic rate of the cells in vitro. Chondrocytes were isolated from the proximal tibial growth plate of the lamb fetuses between 35 and 132 days' gestation using collagenase, and were cultured in monolayer before use between passages 3 and 6. Viability was confirmed over the duration of the experiments by the exclusion of trypan blue, and an absence of lactate dehydrogenase accumulation in conditioned medium. Immunocytochemistry of chondrocyte monolayers showed immunoreactive basic FGF to be present in the cytoplasm of approximately 80% of sub-confluent cells which was accompanied by pronounced nuclear staining in approximately 30% of cells. Serum-free, conditioned culture medium, extracellular matrix and chondrocyte cytoplasm contained 52 +/- 2 pM/micrograms DNA, 66 +/- 2 pM/micrograms DNA and 22 +/- 3 pM/micrograms DNA basic FGF, respectively (mean +/- S.E.M., n = 8 fetuses), for cells obtained from animals of 35-40 days' gestation when assessed by radioimmunoassay. Chondrocyte-conditioned medium increased endothelial cell proliferation in vitro (a specific bio-assay for basic FGF and related peptides); and the mitogenic activity was removed from conditioned medium by incubation with heparin-Sepharose demonstrating that this was due to heparin-binding protein(s). Western blot analysis of conditioned medium using a specific basic FGF antibody revealed a single immunoreactive protein of approximately 18 kDa molecular size. The appearance of radiommunoassayable basic FGF in conditioned medium, extracellular matrix, and chondrocyte cytoplasm observed during culture was blocked by co-incubation with cycloheximide. The levels of immunoreactive basic FGF present in each compartment decreased with gestational age as did basal DNA synthetic rate assessed by the incorporation of [3H] thymidine. Incubation of chondrocytes with transforming growth factor beta, resulted in a significant increase while exposure to insulin-like growth factors or insulin caused a decrease, in the content and release of basic FGF. Basic FGF presence was unaltered when medium was supplemented with varying amounts of glucose (2.7-16.7 mM). In situ hybridization on cell monolayers using a cRNA probe encoding the high affinity flg receptor for FGFs showed an abundant expression of mRNA for the receptor.(ABSTRACT TRUNCATED AT 400 WORDS)

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Acidic fibroblast growth factor (FGF) from bovine brain: amino-terminal sequence and comparison with basic FGF.

Bőhlen¹,

Esch²,

Baird³

et al. 1985

The EMBO Journal

168

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Acidic fibroblast growth factor (FGF) from bovine brain has been isolated by a combination of salt precipitation, ion‐exchange chromatography, heparin‐Sepharose affinity chromatography and reverse phase h.p.l.c. The amino acid composition of the mitogen is indistinguishable from that of acidic FGF previously purified. The amino‐terminal sequence of acidic FGF was established as Phe‐Asn‐Leu‐ Pro‐Gly‐Asn‐Tyr‐Lys‐Pro‐Lys‐Leu‐X‐Tyr‐X‐Ser‐Asn‐Gly‐X‐Tyr‐Phe‐Leu‐Arg‐Il e‐Leu‐Pro‐Asp‐Gly. Acidic FGF is structurally different from basic FGF as judged by mol. wt., amino acid composition and sequence. In vitro biological comparison of the two growth factors indicates that acidic and basic FGFs possess the same intrinsic activities to stimulate the proliferation of aorta, vein or capillary endothelial cells and adrenal cortex cells, but acidic FGF is 30‐100 times less potent, depending on the cell type.

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Characterization of growth factors in human cartilage

Cited by 16 publications

References 15 publications

Differential effects of transforming growth factor‐β and epidermal growth factor on the cell cycle of cultured rabbit articular chondrocytes

Differential effects of transforming growth factor‐β and epidermal growth factor on the cell cycle of cultured rabbit articular chondrocytes

Basic Fibroblast Growth Factor is Synthesized and Released by Isolated Ovine Fetal Growth Plate Chondrocytes: Potential Role as an Autocrine Mitogen

Acidic fibroblast growth factor (FGF) from bovine brain: amino-terminal sequence and comparison with basic FGF.

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