Localisation of mRNA for collagenase in osteocytic, bone surface and chondrocytic cells but not osteoclasts

1995 ◽  
Vol 108 (6) ◽  
pp. 2221-2230
Author(s):  
K. Fuller ◽  
T.J. Chambers
Keyword(s):  
Bone Resorption ◽  
Bone Cells ◽  
In Situ Hybridisation ◽  
Cysteine Proteinases ◽  
Bone Surface ◽  
Matrix Metalloproteinase 1 ◽  
Osteoclastic Resorption ◽  
Stimulation Of

Osteoclasts resorb the extracellular matrix of bone by secreting protons and enzymes into a circumpherentially sealed compartment between the osteoclast and the bone surface. Although the lysosomal cysteine proteinases play a major role in matrix degradation by osteoclasts, collagenase (matrix metalloproteinase-1, EC 3.4.24.7) is also required for osteoclastic bone resorption, and may be directly involved in collagen degradation in the hemivacuole. We assessed the effects of inhibitors of cysteine proteinases and collagenase on bone resorption by osteoclasts isolated from rodent bone. We found that while inhibition of cysteine proteinases strongly suppressed osteoclastic resorption, inhibitors of collagenase were without effect on the number, size, or demineralised fringe of excavations. We could find no evidence of expression of mRNA for collagenase in rat osteoclasts by in situ hybridisation, but found that it was expressed by chondrocytes, bone surface cells and osteocytes adjacent to osteoclasts. The distribution of these cells, and the correlation between increased collagenase production and increased stimulation of osteoclastic resorption in vitro by bone cells, suggests that these cells might be involved in the regulation of bone resorption in situ, and that collagenase production might play a role in this process.

The effect of sex hormones on bone resorption by rat osteoclasts

1991 ◽  
Vol 124 (1) ◽  
pp. 121-127 ◽  
Author(s):  
J. H. Tobias ◽  
T. J. Chambers
Keyword(s):  
Bone Resorption ◽  
Sex Hormones ◽  
Neonatal Rat ◽  
Osteoblastic Cells ◽  
Long Bones ◽  
Bone Surface ◽  
Estradiol 17Β ◽  
Scanning Electron ◽  
Stimulation Of

Abstract. Although sex hormones are important in the attainment and maintenance of bone mass, the mechanism by which they exert their effect is unknown. We therefore tested the effects of estradiol-17β, dihydrotestosterone, and progesterone on osteoclasts, the cells that resorb bone. Osteoclasts were disaggregated from neonatal rat long bones, and incubated with or without the addition of osteoblastic cells or osteoblast-like cell lines. Bone resorption was assessed by scanning electron microscopy as the extent of excavation of the bone surface after incubation. We found dihydrotestosterone (1-100 nmol/l) and progesterone (10-1000 nmol/l) to have no significant effect on bone resorption. By contrast, E2 (1 nmol/l) reduced bone resorption in osteoclast cultures to which osteoblasts had been added, by approximately 25%, although consistent inhibition with other concentrations (0.01, 0.1, 10 nmol/l) was not observed. To our surprise, E2 was also associated with a delayed, dose-responsive, stimulation of bone resorption, in the range 0.1-10 nmol/l, in osteoclast cultures free from added osteoblastic cells. Tamoxifen, which itself had no effect on bone resorption, appeared to antagonise these E2 effects. Although the physiological significance of the stimulatory effect is unclear, we hypothesize that its presence prevented us, and previous workers, from observing doseresponsive inhibition of bone resorption by E2 in vitro.

scholarly journals Osteogenic periosteum esterase activity: a comparative morphological and cytochemical study of bone cells in situ on rat proximal tibiae and in smears.

1984 ◽  
Vol 32 (1) ◽  
pp. 55-62 ◽  
Author(s):  
W L Ries
Keyword(s):  
Bone Resorption ◽  
Esterase Activity ◽  
Bone Cells ◽  
Bone Matrix ◽  
Hydrolytic Enzyme ◽  
Moderate Intensity ◽  
Isolated Cells ◽  
Cytochemical Study

Mononucleate phagocytes are presently thought to participate, along with osteoclasts, in bone resorption. Similar cells may also be precursors to osteoclasts. Esterase is a hydrolytic enzyme commonly found in most phagocytes and cells such as these have been shown to degrade bone matrix in vitro. Therefore, periosteal cells of remodeling proximal tibiae in rats were examined for esterase activity. Stain reactions were compared both in situ and in smears. Percentages of different cell types were obtained by counting cells in Wright-Giemsa-stained smears. Osteoclasts and mononucleate phagocyte-like cells made up approximately 20% of the isolated cells. Cells resembling preosteoblasts, mononucleate phagocytes, and osteoblasts stained for esterase activity with light to moderate intensity. Osteoclasts and mononucleate osteoclast-like cells were strongly esterase positive. The esterase was characterized as being type B by using nonorganophosphorus inhibitors of the various esterase types. The addition of esterase to the list of enzyme activities of cells in close proximity to osteoclasts lends further support to the hypothesis that mononucleate cells also participate in bone resorption.

scholarly journals Potent and Selective Cathepsin L Inhibitors Do Not Inhibit Human Osteoclast Resorptionin Vitro

2001 ◽  
Vol 276 (15) ◽  
pp. 11507-11511 ◽  
Author(s):  
Ian E. James ◽  
Robert W. Marquis ◽  
Simon M. Blake ◽  
Shing Mei Hwang ◽  
Catherine J. Gress ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Cathepsin L ◽  
Cathepsin K ◽  
Cysteine Proteases ◽  
Cathepsin Activity ◽  
Osteoclastic Resorption ◽  
Human Osteoclast

Cathepsins K and L are related cysteine proteases that have been proposed to play important roles in osteoclast-mediated bone resorption. To further examine the putative role of cathepsin L in bone resorption, we have evaluated selective and potent inhibitors of human cathepsin L and cathepsin K in anin vitroassay of human osteoclastic resorption and anin situassay of osteoclast cathepsin activity. The potent selective cathepsin L inhibitors (Ki= 0.0099, 0.034, and 0.27 nm) were inactive in both thein situcytochemical assay (IC50> 1 μm) and the osteoclast-mediated bone resorption assay (IC50> 300 nm). Conversely, the cathepsin K selective inhibitor was potently active in both the cytochemical (IC50= 63 nm) and resorption (IC50= 71 nm) assays. A recently reported dipeptide aldehyde with activity against cathepsins L (Ki= 0.052 nm) and K (Ki= 1.57 nm) was also active in both assays (IC50= 110 and 115 nm, respectively) These data confirm that cathepsin K and not cathepsin L is the major protease responsible for human osteoclastic bone resorption.

Mechanisms of airway hypercontractility in basenji-greyhound dogs

1987 ◽  
Vol 63 (5) ◽  
pp. 2008-2014 ◽  
Author(s):  
T. M. Murphy ◽  
N. M. Munoz ◽  
C. A. Hirshman ◽  
J. S. Blake ◽  
A. R. Leff
Keyword(s):  
Maximal Response ◽  
Adrenergic Blockade ◽  
Vagus Nerves ◽  
Response Curves ◽  
Bronchial Smooth Muscle ◽  
Muscarinic Response ◽  
Contractile Forces ◽  
Stimulation Of

The comparative effects of contractile agonists and physiological stimulation of the tracheal and bronchial smooth muscle (BSM) response were studied isometrically in situ in five Basenji-greyhound (BG) and six mongrel dogs. Frequency-response curves generated by bilateral stimulation of the vagus nerves (0–20 Hz, 15–20 V, 2-ms duration) elicited greater maximal contraction in mongrel trachea (36.8 +/- 8.1 vs. 26.9 +/- 4.0 g/cm; P less than 0.02) and exhibited greater responsiveness in mongrel BSM (half-maximal response to electrical stimulation 3.0 +/- 1.1 vs. 7.0 +/- 0.5 Hz; P less than 0.05) compared with BG dogs. However, muscarinic sensitivity to intravenous methacholine (MCh) was substantially greater in BG dogs; MCh caused contraction greater than 1.5 g/cm at a mean dose of 3.0 X 10(-10) mol/kg for BG dogs compared with 5.1 X 10(-9) mol/kg for mongrel controls (P less than 0.03, Mann-Whitney rank-sum test). In contrast to the muscarinic response, the contractile response elicited by intravenous norepinephrine after beta-adrenergic blockade was similar in trachea and bronchus for both mongrel and BG dogs. Our data confirm previous in vitro demonstration of tracheal hyporesponsiveness in BG dogs and demonstrate that the contraction resulting from efferent parasympathetic stimulation is less in the BG than mongrel dogs. However, postsynaptic muscarinic responsiveness of BG BSM is substantially increased. We conclude that a component of airway responsiveness in BG dogs depends directly on contractile forces generated postsynaptically that are nongeometry dependent, postjunctional, and agonist specific.

Effect of Substrate Surface Modification on Biomineralization of Osteoblasts

2006 ◽  
Vol 950 ◽  
Author(s):  
Yizhi Meng ◽  
Xiaolan Ba ◽  
Seo-Young Kwak ◽  
Elaine DiMasi ◽  
Meghan Ruppel ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Bone Cells ◽  
Bone Mineralization ◽  
Substrate Surface ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Tissue Scaffold ◽  
Actin Fiber

ABSTRACTUnderstanding how biomineralization occurs in the extracellular matrix (ECM) of bone cells is crucial to the development of a successfully engineered bone tissue scaffold, and to date there has not been a well-established method for the quantitative examination of bone mineralization in situ. We investigated the mechanical properties of MC3T3-E1 osteoblast-like cells and the crystalline properties of their biomineralized ECM in vitro using shear modulation force microscopy (SMFM), confocal laser scanning microscopy (CLSM), synchrotron X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The elastic modulus of the mineralizing cells increased at time points corresponding to mineral production, whereas that of the non-mineralizing cells did not vary significantly over time. CLSM showed a restructuring of the F-actin fiber network of mineralizing cells with time, which indicates remodeling activities in the cytoskeleton and was not seen in the non-mineralizing cells. Both XRD and FTIR showed that the mineralizing subclone produced hydroxyapatite in situ and that the non-mineralizing subclone was in fact weakly biomineralizing.

Differential effects of glucocorticoids on bone resorption in neonatal mouse calvariae stimulated by peptide and steroid-like hormones

1997 ◽  
Vol 155 (3) ◽  
pp. 513-521 ◽  
Author(s):  
HH Conaway ◽  
D Grigorie ◽  
UH Lerner
Keyword(s):  
Bone Resorption ◽  
Vitamin D3 ◽  
Neonatal Mouse ◽  
Receptor Interaction ◽  
Differential Effects ◽  
All Trans Retinoic Acid ◽  
45Ca Release ◽  
Stimulation Of

Differential effects on in vitro bone resorption were observed when the glucocorticoids, hydrocortisone and dexamethasone, were added to neonatal mouse calvariae treated with either parathyroid hormone (PTH), 1,25(OH)2-vitamin D3, all trans-retinoic acid (t-RA), or prostaglandin E2 (PGE2). Bone resorption was assessed by analyzing either the release of 45Ca from [45Ca]CaCl2 prelabeled calvarial bones or the release of 3H from [3H]proline prelabeled calvariae. At PGE2 concentrations of 3 x 10(-8) and 3 x 10(-7) mol/l, co-treatment with either 10(-6) mol/l dexamethasone or 10(-6) mol/l hydrocortisone caused additive 45Ca release from neonatal mouse calvariae. In contrast, synergistic release from mouse calvarial bones of both 45Ca and 3H was found after either 10(-6) mol/l hydrocortisone or 10(-6) mol/l dexamethasone was combined with 3 x 10(-11) mol/l PTH treatment for 120 h. Dose-response studies indicated that the synergistic stimulation of 45Ca release from neonatal mouse calvariae by glucocorticoids and PTH could be elicited at glucocorticoid concentrations of 10(-8) to 10(-6) mol/l and at PTH concentrations of 10(-11) to 10(-9) mol/l. Progesterone and RU 38486 (a derivative of 19-nortestosterone with antiglucocorticoid activity) blocked the synergism noted with glucocorticoid and PTH co-treatment, suggesting that interaction between the steroids and PTH was dependent on glucocorticoid receptor interaction. Addition of either 10(-6) mol/l hydrocortisone or 10(-6) mol/l dexamethasone to neonatal mouse calvariae treated with 1,25(OH)2-vitamin D3 (10(-11) and 10(-10) mol/l) also resulted in synergistic stimulation of 45Ca release. In contrast to these observations, the stimulatory effect of t-RA (10(-8) mol/l) on 45Ca release from calvarial bones was abolished in the presence of 10(-6) mol/l dexamethasone. These results suggest that an important role of glucocorticoids may be to synergistically potentiate bone resorption stimulated by PTH and 1,25(OH)2-vitamin D3, but indicate an opposing interaction between the glucocorticoids and bone resorptive retinoids.

scholarly journals Osteoblasts mediate interleukin 1 stimulation of bone resorption by rat osteoclasts.

1986 ◽  
Vol 164 (1) ◽  
pp. 104-112 ◽  
Author(s):  
B M Thomson ◽  
J Saklatvala ◽  
T J Chambers
Keyword(s):  
Bone Resorption ◽  
Interleukin 1 ◽  
Fold Increase ◽  
Osteoclastic Bone Resorption ◽  
Neonatal Rat ◽  
Osteoblastic Cells ◽  
Computer Assisted ◽  
Osteoclastic Resorption ◽  
Primary Action ◽  
Stimulation Of

A monocyte-derived factor with IL-1-like properties has recently been shown to cause resorption of bone in organ culture. We have investigated the action of IL-1 on disaggregated populations of osteoclasts, incubated alone or in the presence of osteoblastic cells, in an attempt to identify the target cell for IL-1 in bone, and to elucidate the mechanism by which IL-1 induces osteoclastic resorption. Osteoclasts were disaggregated from neonatal rat long bones and incubated on slices of human femoral cortical bone. Under these conditions, the majority of osteoclasts form distinctive excavations in the bone surface within 24 h, the volume of which can be quantified by computer-assisted morphometric and stereophotogrammetic techniques. IL-1 had no effect on bone resorption by osteoclasts alone, but when incubated in the presence of calvarial cells or cloned osteosarcoma cells, it induced a 3.8 (+/- 0.38)-fold increase in osteoclastic bone resorption, with significant enhancement at concentrations of greater than or equal to 30 pg/ml. The osteoblastic populations themselves did not resorb bone. The mechanism by which osteoblastic cells stimulate osteoclasts did not appear to depend upon PG synthesis; nor could we detect a diffusible substance in the medium of stimulated cocultures. These results indicate that IL-1 stimulates bone resorption through a primary action on osteoblasts, which are induced by IL-1 to transmit a short-range signal that stimulates osteoclastic bone resorption.

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