Pi transport regulation by chicken growth plate chondrocytes

1994 ◽  
Vol 267 (1) ◽  
pp. E24-E31
Author(s):  
C. Montessuit ◽  
J. P. Bonjour ◽  
J. Caverzasio
Keyword(s):  
Growth Plate ◽  
Primary Cultures ◽  
Growth Plate Chondrocytes ◽  
Phosphonoformic Acid ◽  
Pi Transport ◽  
Igf I ◽  
Sodium Dependent ◽  
Half Maximal Effective Concentration ◽  
Cartilage Cells ◽  
Extracellular Sodium

Inorganic phosphate (Pi) is a key element for the growth and mineralization of the epiphyseal cartilage. In this study, the characteristics of the transport of Pi in growth plate chondrocytes have been determined using primary cultures of chicken growth plate cartilage cells. The uptake of Pi was significantly increased in the presence of extracellular sodium. The kinetic parameters of the saturable sodium-dependent Pi transport (NaPiT) were determined. The Michaelis constant for Pi was 0.443 +/- 0.095 mM, and the concentration of sodium with which half-maximal Pi transport was observed was 48.0 +/- 8.7 mM. Stoichiometric analysis suggested that more than one sodium ion was cotransported with each Pi molecule. NaPiT was sensitive to inhibition by Pi analogues such as phosphonoformic acid and arsenate. These data strongly suggest that Pi uptake by chicken growth plate chondrocytes is a carrier-mediated process driven by the transmembrane electrochemical gradient of sodium. Two important regulators of biosynthetic activities of growth plate chondrocytes, insulin-like growth factor I (IGF-I) and parathyroid hormone (PTH), selectively regulated Pi transport. With IGF-I, maximal stimulation (117 +/- 7% above control) was observed at doses > 5 nM, with an half-maximal effective concentration of 0.46 +/- 0.18 nM. A significant effect was observed after 1 h of exposure and was maintained for up to 24 h. PTH increased Pi transport with a biphasic dose-response curve. The change in NaPiT was transient, being maximally observed after 8 h (58 +/- 8%) and unexpressed after 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Inhibition of IGF-I–related intracellular signaling pathways by proinflammatory cytokines in growth plate chondrocytes

2014 ◽  
Vol 76 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Daniela Choukair ◽  
Ulrike Hügel ◽  
Anja Sander ◽  
Lorenz Uhlmann ◽  
Burkhard Tönshoff
Keyword(s):  
Signaling Pathways ◽  
Growth Plate ◽  
Proinflammatory Cytokines ◽  
Intracellular Signaling ◽  
Growth Plate Chondrocytes ◽  
Intracellular Signaling Pathways ◽  
Igf I

scholarly journals Imaging IGF-I uptake in growth plate cartilage using in vivo multiphoton microscopy

2017 ◽  
Vol 123 (5) ◽  
pp. 1101-1109 ◽  
Author(s):  
Maria A. Serrat ◽  
Gabriela Ion
Keyword(s):  
Real Time ◽  
Growth Plate ◽  
Multiphoton Microscopy ◽  
Biologically Active ◽  
Growth Plate Chondrocytes ◽  
Growth Plates ◽  
Metatarsal Bones ◽  
Wide Range ◽  
Igf I

Bones elongate through endochondral ossification in cartilaginous growth plates located at ends of primary long bones. Linear growth ensues from a cascade of biochemical signals initiated by actions of systemic and local regulators on growth plate chondrocytes. Although cellular processes are well defined, there is a fundamental gap in understanding how growth regulators are physically transported from surrounding blood vessels into and through dense, avascular cartilage matrix. Intravital imaging using in vivo multiphoton microscopy is one promising strategy to overcome this barrier by quantitatively tracking molecular delivery to cartilage from the vasculature in real time. We previously used in vivo multiphoton imaging to show that hindlimb heating increases vascular access of large molecules to growth plates using 10-, 40-, and 70-kDa dextran tracers. To comparatively evaluate transport of similarly sized physiological regulators, we developed and validated methods for measuring uptake of biologically active IGF-I into proximal tibial growth plates of live 5-wk-old mice. We demonstrate that fluorescently labeled IGF-I (8.2 kDa) is readily taken up in the growth plate and localizes to chondrocytes. Bioactivity tests performed on cultured metatarsal bones confirmed that the labeled protein is functional, assessed by phosphorylation of its signaling kinase, Akt. This methodology, which can be broadly applied to many different proteins and tissues, is relevant for understanding factors that affect delivery of biologically relevant molecules to the skeleton in real time. Results may lead to the development of drug-targeting strategies to treat a wide range of bone and cartilage pathologies. NEW & NOTEWORTHY This paper describes and validates a novel method for imaging transport of biologically active, fluorescently labeled IGF-I into skeletal growth plates of live mice using multiphoton microscopy. Cellular patterns of fluorescence in the growth plate were completely distinct from our prior publications using biologically inert probes, demonstrating for the first time in vivo localization of IGF-I in chondrocytes and perichondrium. These results form important groundwork for future studies aimed at targeting therapeutics into growth plates.

scholarly journals Dexamethasone-induced growth inhibition of porcine growth plate chondrocytes is accompanied by changes in levels of IGF axis components

2002 ◽  
Vol 174 (2) ◽  
pp. 343-352 ◽  
Author(s):  
JJ Smink ◽  
JA Koedam ◽  
JG Koster ◽  
SC van Buul-Offers
Keyword(s):  
Growth Inhibition ◽  
Growth Plate ◽  
Growth Retardation ◽  
Culture Conditions ◽  
Type I ◽  
Mrna Levels ◽  
Growth Plate Chondrocytes ◽  
Type I Igf Receptor ◽  
Igf I ◽  
Igf Receptor

High (pharmacological) doses of glucocorticoids inhibit the proliferation of growth plate chondrocytes, which leads to one of the side-effects of these steroids, namely suppression of longitudinal growth. Growth inhibition by glucocorticoids is thought to be mediated in part by impaired action of components of the IGF axis, which are important for chondrocyte regulation and hence for longitudinal growth. The aim of the present study was to determine whether glucocorticoid-induced growth retardation involves changes in IGF axis components. Chondrocytes were isolated from epiphyseal growth plates of neonatal piglets and treated with pharmacological doses of dexamethasone (DXM) for 24 h to study glucocorticoid-induced growth retardation. Under IGF-I-supplemented (10 nM) culture conditions, IGF-binding proteins (IGFBPs)-2, -4 and -5 were secreted by the growth plate chondrocytes and IGFBP-2 protein and mRNA levels were decreased by the DXM treatment, whereas IGFBP-4 and -5 were not affected. Proliferation of the chondrocytes, as measured by [(3)H]thymidine incorporation, was 3.5-fold higher in serum-supplemented medium in contrast to IGF-I-supplemented (10 nM) medium. In the presence of serum, DNA synthesis was significantly inhibited by 50-63% when treated with 100 nM DXM, which was prevented by the glucocorticoid-receptor antagonist Org34116. mRNA levels of IGF axis components were determined using Northern blot analysis. IGFBP-2 to -6 were expressed in the chondrocytes, IGFBP-1 was absent and both IGF-I and IGF-II, and the type I and type II IGF receptors were expressed. Treatment with DXM (100 nM) resulted in a 2-fold increase in mRNA levels of both IGFBP-5 and the type I IGF receptor, whereas IGFBP-2 mRNA levels decreased by 55%, in concert with the decrease in protein level observed under IGF-I-supplemented culture conditions. The changes in mRNA levels due to the DXM treatment were prevented by the glucocorticoid receptor antagonist. Our data show that exposure to pharmacological doses of DXM results in inhibition of proliferation and changes in components of the IGF axis, IGFBP-2 and -5 and the type I IGF receptor, suggesting a role for these components in glucocorticoid-induced growth retardation at the local level of the growth plate.

scholarly journals Interaction of IGF-I and 1α,25(OH)2D3 on receptor expression and growth stimulation in rat growth plate chondrocytes

1998 ◽  
Vol 53 (5) ◽  
pp. 1152-1161 ◽  
Author(s):  
Günter Klaus ◽  
Lutz Weber ◽  
Julian Rodríguez ◽  
Porfirio Fernández ◽  
Thomas Klein ◽  
...  
Keyword(s):  
Growth Plate ◽  
Growth Stimulation ◽  
Receptor Expression ◽  
Growth Plate Chondrocytes ◽  
Igf I ◽  
Rat Growth

scholarly journals Ceramide inhibition of chondrocyte proliferation and bone growth is IGF-I independent

2006 ◽  
Vol 191 (2) ◽  
pp. 369-377 ◽  
Author(s):  
V E MacRae ◽  
T Burdon ◽  
S F Ahmed ◽  
C Farquharson
Keyword(s):  
Insulin Receptor ◽  
Growth Plate ◽  
Bone Growth ◽  
Inflammatory Diseases ◽  
Thymidine Uptake ◽  
Growth Plate Chondrocytes ◽  
Igf I ◽  
Presence And Absence ◽  
Underlying Mechanisms ◽  
Induced Apoptosis

Proinflammatory cytokines inhibit growth plate development. However, their underlying mechanisms of action are unclear. These effects may be mediated by ceramide, a sphingosine-based lipid second messenger, which is elevated in a number of chronic inflammatory diseases. To test this hypothesis, we determined the effects of C2-ceramide, a cell permeable ceramide analogue, on the growth of the ATDC5 chondrogenic cell line and on cultured fetal mice metatarsals. In ATDC5 cells, C2-ceramide significantly induced apoptosis at both 40 (82%; P < 0.05) and 25 μM (53%; P < 0.05). At 40 μM, C2-ceramide significantly reduced proliferation ([3H]-thymidine uptake/mg protein) (62%; P < 0.05). C2-ceramide did not markedly alter the differentiation state of the cells as judged by the expression of markers of chondrogenesis and differentiation (sox 9, collagen II and collagen X). The IGF-I signalling pathway is the major autocrine/paracrine regulator of bone growth. Both in the presence and absence of IGF-I, C2-ceramide (25 μM) induced an equivalent reduction in proliferation (60%; P < 0.001). Similarly, C2-ceramide (40 μM) induced a 31% reduction in fetal metatarsal growth both in the presence and absence of IGF-I (both P < 0.001). Furthermore, C2-ceramide reduced ADCT5 proliferation in the presence of AG1024, an IGF-I and insulin receptor blocker. Therefore, C2-ceramide-dependent inhibition appears to be independent of IGF-mediated stimulation of bone growth. Indeed, biochemical studies demonstrated that C2-ceramide (25 μM) pretreatment did not alter IGF-I-stimulated phosphorylation of insulin receptor substrate-1, Akt or P44/42 MAP kinase. In conclusion, C2-ceramide inhibits proliferation and induces apoptosis in growth plate chondrocytes through an IGF-I independent mechanism.

scholarly journals Defined Carboxy-Terminal Fragments of Insulin-Like Growth Factor (IGF) Binding Protein-2 Exert Similar Mitogenic Activity on Cultured Rat Growth Plate Chondrocytes as IGF-I

Endocrinology ◽  
2008 ◽  
Vol 149 (10) ◽  
pp. 4901-4911 ◽  
Author(s):  
Daniela Kiepe ◽  
Anke Van Der Pas ◽  
Sonia Ciarmatori ◽  
Ludger Ständker ◽  
Burkhardt Schütt ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Biological Activity ◽  
Growth Plate ◽  
Longitudinal Growth ◽  
Growth Plate Chondrocytes ◽  
Igf I ◽  
Rat Growth ◽  
Igf Binding ◽  
Carboxy Terminal ◽  
Igf Binding Protein

The IGF/IGF binding protein (IGFBP) system is an important component in the hormonal regulation of longitudinal growth. Evidence from in vitro studies indicates that IGFBPs may have IGF-independent effects. We analyzed the biological activity of intact IGFBP-2 and defined carboxy-terminal IGFBP-2 fragments isolated from human hemofiltrate in two cell culture systems of the growth plate: rat growth plate chondrocytes in primary culture and the mesenchymal chondrogenic cell line RCJ3.1C5.18. The IGFBP-2 fragments IGFBP-2167–279, IGFBP-2167–289, and IGFBP-2104–289 exerted a strong (2- to 3-fold) mitogenic effect on growth plate chondrocytes, which was comparable with IGF-I in equimolar concentrations (7.8 nm) but was not mediated through the type 1 IGF receptor. In a dose-response experiment, the most effective concentration of IGFBP-2104–289 for the stimulation of cell proliferation was 10 nm. This biological activity of IGFBP-2 fragments was associated with cell membrane binding, demonstrated by Western blot analysis of fractionated cell lysates and immunohistochemistry. Whereas intact IGFBP-2 did not modulate chondrocyte proliferation, partially reduced (by dithiothreitol) full-length IGFBP-2 stimulated cell proliferation to a comparable extent (3.4-fold) as carboxy-terminal IGFBP-2 fragments. The mitogenic activity of these IGFBP-2 fragments and of partially reduced full-length IGFBP-2 was mediated through the use of the MAPK/ERK 1/2. These data imply a novel role of naturally occurring IGFBP-2 fragments for the endocrine and paracrine/autocrine regulation of longitudinal growth.

Differential expression of IGF system components in proliferating vs. differentiating growth plate chondrocytes: the functional role of IGFBP-5

2006 ◽  
Vol 290 (2) ◽  
pp. E363-E371 ◽  
Author(s):  
Daniela Kiepe ◽  
Sonia Ciarmatori ◽  
Anke Haarmann ◽  
Burkhard Tönshoff
Keyword(s):  
Cell Culture ◽  
Growth Plate ◽  
Functional Role ◽  
Growth Plate Chondrocytes ◽  
Igf System ◽  
System Components ◽  
Igf I ◽  
Culture Models ◽  
Cell Culture Models ◽  
Igfbp 3

The growth plate is an important target tissue for insulin-like growth factors (IGFs), but little is known about the regulation of the IGF system during the developmental sequence of chondrocytes. We therefore examined the expression profile of IGF system components in proliferating vs. differentiating growth plate chondrocytes by use of two cell culture models of the growth cartilage. In rat growth plate chondrocytes in primary culture, IGF-I expression increased twofold during the process of differentiation. IGF-binding protein-3 (IGFBP-3) expression showed a biphasic pattern of with a twofold increase at the onset of differentiation and a downregulation in late differentiating chondrocytes to 25% of baseline levels; the expression patterns of IGFBP-2, -4 and -6 were not dependent on the developmental stage. In IGF- and IGFBP-3-deficient RCJ3.1C5.18 (RCJ) mesenchymal chondrogenic cells, IGFBP-2 and -6 synthesis declined by 50% during differentiation. IGFBP-5 expression was markedly upregulated during the process of differentiation in both cell culture models. Although IGFBP-5 overexpression did not have an IGF-independent effect on RCJ cell differentiation, it promoted IGF-I-enhanced differentiation of these cells. A potential mechanism for this effect is the specific increase of Akt phosphorylation in IGFBP-5-overexpressing cells in the presence of IGF-I, indicating an increased activity of the phosphatidylinositol (PI) 3-kinase pathway. These data suggest that the developmental stage of the chondrocyte is an important determinant of IGF and IGFBP expression and imply a functional role for IGFBP-5 for upregulating IGF action during chondrocyte differentiation in vivo.

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