Cytoplasmic dexamethasone receptors in embryonic chick cartilage: Nature and ontogeny

Lee, Jason A.; Hicks, David C.; Hughes, Edwin R.; Smith, D. J.; Elders, M. Joycelyn

doi:10.1016/0022-4731(78)90096-1

Cited by 17 publications

(5 citation statements)

References 13 publications

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“…The maximally effective concentration and the ED 50 for the stimulation were consistent with the DEX effect being mediated by glucocorticoid receptors, which are present in chondrogenic cells (34)(35)(36). The cartilage nodules that formed in the presence of DEX were larger than those formed in its absence, and new nodules developed in discrete areas of the documented suppression by glucocorticoids of markers for the cartilage phenotype, both in vitro and in vivo (12,36,37).…”

Section: Discussionmentioning

confidence: 56%

Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

1989

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We have investigated the regulation of chondroblast/chondrocyte differentiation using a unique clonal cell population, designated RCJ 3.1C5 (C5), which differentiates into discrete three-dimensional cartilage nodules when grown in the presence of 15% fetal calf serum. Histologically, the nodules resembled hyaline cartilage; they contained large rounded chondrocytes surrounded by a refractile matrix which stained intensely with Alcian blue, exhibited metachromasia after Toluidine blue staining, and stained with an antibody against type II collagen. The cartilage nodules that formed did not mineralize, despite the presence of organic phosphate in the culture medium. The synthetic glucocorticoid dexamethasone (DEX) increased the number of cartilage nodules formed in a dose-dependent manner (ED50, approximately 10(-9) M), with a maximal stimulatory dose of 10(-8) M. DEX had no effect on the population doubling time and saturation density. The effects of DEX on the number of cartilage nodules were similar whether it was added from the beginning of the culture period (starting during exponential growth) or at confluence. In contrast, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] inhibited cartilage nodule formation in a dose-dependent manner (IC50, approximately 5 x 10(-10) M), with maximum inhibition at 10(-7) M. In addition, 1,25-(OH)2D3 decreased cell proliferation and saturation density. Equimolar doses of the vitamin D3 metabolites 24,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 had no effect. C5 cells treated with 1,25-(OH)2D3 in the absence of DEX during the exponential growth phase exhibited a reduced capacity to form cartilage nodules upon subsequent exposure to DEX. At confluence, before cartilage nodules had formed, C5 cells responded to PTH and prostaglandin-E2 with increases in intracellular cAMP of about 10- and 95-fold respectively. After cartilage nodules were present, prostaglandin-E2 responsiveness decreased to about 25-fold, whereas there was no significant change in PTH responsiveness. DEX decreased the population alkaline phosphatase levels at all times measured, whereas 1,25-(OH)2D3 had a biphasic effect: an increase at 5 days in culture, followed by a decrease at later times in culture. These data indicate that the clonal cell line RCJ 3.1C5 is a useful model system in which to investigate cartilage differentiation.

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Section: Discussionmentioning

confidence: 56%

Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

1989

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“…We were unable to detect androgen and progesterone receptors in this tissue. The presence of glucocorticoid receptors in embryonic chick growth cartilage has been described (16), and there is preliminary evidence to show that macromolecules with some binding characteristics similar to those of glucocorticoid receptors were also present in cultured rabbit articular chondrocytes (2). Interpretation of this latter finding is complicated by the potential of chondrocytes to dedifferentiate in culture to fibroblastic cells, which are known to contain glucocorticoid receptors (17).…”

Section: Discussionmentioning

confidence: 99%

Estrogen and glucocorticoid receptors in adult canine articular cartilage

Young¹,

Stack²

1982

Arthritis & Rheumatism

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The cytoplasmic and crude nuclear fractions of adult mongrel dog articular cartilage contained estradi-01-and dexamethasone-binding components which had properties of physiologic steroid receptors. The equilibrium dissociation constants averaged 0.37 nM for estradiol and 2.27 nM for dexamethasone. The concentrations of estrogen receptors ranged from below 6 to 101 fmolhg protein in the cytosols and from below 2.8 to 17.5 fmol/pg DNA in the nuclear fractions. Glucocorticoid receptors were detected in only 4 of 13 cytosols (range: 61.2-132 fmolhg protein), whereas 10 of 13 nuclear fractions contained 0.8 to 46.8 femtomoles of the receptors for each microgram of DNA. There appeared to be no marked difference between the contents of either steroid receptor in female or male dog cartilage. No receptors were detected for androgen and progesterone.Cartilage has recently been found to bear cellular receptors for both insulin and glucocorticoids ( I ,2). Whether articular cartilage is a target organ for estrogen, which is known to increase the mechanical strength of the cartilage growth plate in rats (3). is not known. Studies in vivo have shown chondrocyte hypertrophy, decreased )'SO4 incorporation, and decreased turnover of proteoglycan in response to estrogen administration (4.5). The mechanism of estrogen's action on chondrocytes is unknown; blockade of somatomedin effects has been postulated as a mechanism (43). Srudies in vitro have yielded conflicting results about "SO4 uptake (4). We have previously demonstrated that changes of cartilage matrix in vitro. especially enhancement of hyaluronic acid synthesis, are mediated by the dibutyryl analog of cyclic adenosine monophosphate (6). A recent study of mouse skin revealed enhanced hyaluronic acid synthesis in response to estrogen: the response was proportional to the number of estrogen receptors present in the male mouse skin used (7).Other studies have revealed that testosterone and cortisol also affect cartilage in vivo by enhancing hyaluronic acid synthesis and depressing 35S04 incorporation in vivo. respectively; the mechanisms are under investigation (4). This study was designed to determine if receptors for estrogen, progestin. androgen, and cortisol exist in adult canine cartilage, and, if so, the relative number and cellular compartmentalization of those found. MATERIALS AND METHODSBuffers. Two buffers were used in this study. Buffer pH 7.6 at 4°C. 7.4 at 25°C. Buffer B was buffer A that contained 10% glycerol.Tissues. Cartilage was collected in iced buffer A from

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“…During the past several years, the presence of a glucocorticoid receptor has been demonstrated in various cartilage tissues (Lee et al 1978;Blondelon et al 1980;Maor & Silbermann 1982;Kan et al 1983). Due to the fact that glucocorticoids have complex direct and indirect effects on cartilage, our understanding of the regulation of cartilage development is still incomplete.…”

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confidence: 96%

Receptor-mediated glucocorticoid inhibition of cell proliferation in mouse growth cartilage in vitro

Silbermann

Maor

1985

Acta Endocrinologica

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Cytoplasmic dexamethasone receptors in embryonic chick cartilage: Nature and ontogeny

Cited by 17 publications

References 13 publications

Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

Estrogen and glucocorticoid receptors in adult canine articular cartilage

Receptor-mediated glucocorticoid inhibition of cell proliferation in mouse growth cartilage in vitro

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Cytoplasmic dexamethasone receptors in embryonic chick cartilage: Nature and ontogeny

Cited by 17 publications

References 13 publications

Effects of Dexamethasone and Vitamin D3on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

Effects of Dexamethasone and Vitamin D3on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

Estrogen and glucocorticoid receptors in adult canine articular cartilage

Receptor-mediated glucocorticoid inhibition of cell proliferation in mouse growth cartilage in vitro

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Product

Resources

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Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population

Effects of Dexamethasone and Vitamin D₃on Cartilage Differentiation in a Clonal Chondrogenic Cell Population