Mice lacking tartrate-resistant acid phosphatase (Acp 5) have disrupted endochondral ossification and mild osteopetrosis

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 3151-3162 ◽  
Author(s):  
A.R. Hayman ◽  
S.J. Jones ◽  
A. Boyde ◽  
D. Foster ◽  
W.H. Colledge ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Endochondral Ossification ◽  
Bone Matrix ◽  
Axial Skeleton ◽  
Mutant Mice ◽  
Intrinsic Defect ◽  
Tartrate Resistant Acid Phosphatase ◽  
Long Bones ◽  
Electron Imaging

Mature osteoclasts specifically express the purple, band 5 isozyme (Acp 5) of tartrate-resistant acid phosphatase, a binuclear metalloenzyme that can generate reactive oxygen species. The function of Acp 5 was investigated by targeted disruption of the gene in mice. Animals homozygous for the null Acp 5 allele had progressive foreshortening and deformity of the long bones and axial skeleton but apparently normal tooth eruption and skull plate development, indicating a role for Acp 5 in endochondral ossification. Histomorphometry and mineralization density analysis of backscattered electron imaging revealed widened and disorganized epiphyseal growth plates with delayed mineralization of cartilage in 6- to 8-week-old mutant mice. The membrane bones of the skull showed increased density at all ages examined, indicating defective osteoclastic bone turnover. Increased mineralization density was observed in the long bones of older animals which showed modelling deformities at their extremities: heterozygotes and homozygous Acp 5 mutant mice had tissue that was more mineralized and occupied a greater proportion of the bone in all regions. Thus the findings reflect a mild osteopetrosis due to an intrinsic defect of osteoclastic modelling activity that was confirmed in the resorption pit assay in vitro. We conclude that this bifunctional metalloprotein of the osteoclast is required for normal mineralization of cartilage in developing bones; it also maintains integrity and turnover of the adult skeleton by a critical contribution to bone matrix resorption.

scholarly journals 1,25-Dihydroxy-19-nor-vitamin D2, a Vitamin D Analog with Reduced Bone Resorbing Activity In Vitro

2000 ◽  
Vol 11 (10) ◽  
pp. 1857-1864
Author(s):  
L. SHANNON HOLLIDAY ◽  
STEPHEN L. GLUCK ◽  
EDUARDO SLATOPOLSKY ◽  
ALEX J. BROWN
Keyword(s):  
Vitamin D ◽  
Acid Phosphatase ◽  
Bone Resorption ◽  
Vitamin D Receptor ◽  
Intrinsic Activity ◽  
Tartrate Resistant Acid Phosphatase ◽  
Mouse Bone Marrow ◽  
Bone Resorbing Activity

Abstract. 1,25-Dihydroxy-19-nor-vitamin D2 (19-norD2), a new analog of 1,25(OH)2D3, suppresses parathyroid hormone in renal failure patients and in uremic rats but has less calcemic activity than 1,25(OH)2D3. Although 19-norD2 has high affinity for the vitamin D receptor and similar pharmacokinetics to those of 1,25(OH)2D3, it has much less bone resorbing activity in vivo. The intrinsic activity of 19-norD2 on osteoclastogenesis and activation of bone resorption in mouse bone marrow cultures was examined to determine the mechanism involved. 19-norD2 and 1,25(OH)2D3 (10 nM) were equivalent in stimulating the formation and maintenance of large multinucleated, tartrate-resistant acid phosphatase-positive cells. However, the amount of bone resorbed by osteoclasts stimulated by 10 nM 19-norD2, as measured by pit-forming assays, was reduced 62% compared with 10 nM 1,25(OH)2D3-stimulated osteoclasts (P < 0.05). This difference could not be attributed to enhanced catabolism or to downregulated vitamin D receptor. The rate of degradation of 19-norD2 in cultures was approximately 20% greater than 1,25(OH)2D3, not enough to account for the different effects on bone resorption. The VDR levels were identical in cultures that were treated with 19-norD2 and 1,25(OH)2D3. In summary, 19-norD2 is less effective than 1,25(OH)2D3 in stimulating mouse marrow osteoclasts to resorb bone. The reason for this difference is not clear but seems to involve the late maturation and/or activation of osteoclasts as the number of pits produced by each tartrate-resistant acid phosphatase-positive cell is reduced under stimulation by 19-norD2 compared with 1,25(OH)2D3.

scholarly journals Chick osteoblasts contain fluoride-sensitive acid phosphatase activity.

1988 ◽  
Vol 36 (9) ◽  
pp. 1175-1180 ◽  
Author(s):  
M W Lundy ◽  
K H Lau ◽  
H C Blair ◽  
D J Baylink
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Bone Matrix ◽  
Competitive Inhibitor ◽  
Cellular Origin ◽  
Embryonic Chicken ◽  
Low Concentrations

We used histological and biochemical methods to determine the cellular origin of bone matrix fluoride-sensitive acid phosphatase in chicken bone. Embryonic chicken calvariae were embedded in plastic and sections stained for acid phosphatase at various concentrations of substrate and fluoride. Acid phosphatase activity was observed in osteoblasts and osteoclasts but not in fibroblasts. Striking inhibition of osteoblastic acid phosphatase occurred at 100 microM fluoride, a concentration that had no apparent effect on osteoclastic acid phosphatase. Inhibition of osteoblastic and osteoclastic acid phosphatase by fluoride was also examined using extracts of embryonic chicken calvarial cells, mouse osteoblasts (MC3T3-El cell line), and purified chick osteoclasts, respectively. Fluoride is a partial competitive inhibitor of both chicken and mouse osteoblastic acid phosphatases, with apparent inhibition constants of 10-100 microM. These concentrations of fluoride correspond to those that increase bone formation in vitro and in vivo. In contrast, the apparent inhibition constant for fluoride of osteoclastic acid phosphatase was much higher (i.e., 0.5 mM). In summary, this study demonstrates that chicken osteoblasts contain an acid phosphatase that is sensitive to inhibition by low concentrations (i.e., microM) of fluoride.

scholarly journals Tartrate-resistant acid phosphatase from human osteoclastomas is translated as a single polypeptide

1991 ◽  
Vol 277 (3) ◽  
pp. 631-634 ◽  
Author(s):  
A R Hayman ◽  
A J Dryden ◽  
T J Chambers ◽  
M J Warburton
Keyword(s):  
Acid Phosphatase ◽  
Peptide Bond ◽  
Northern Blotting ◽  
Tartrate Resistant Acid Phosphatase ◽  
Acid Phosphatases ◽  
Post Translational Modification ◽  
Subunit Protein ◽  
Single Polypeptide ◽  
Single Peptide

Tartrate-resistant acid phosphatases have been isolated from a number of sources. These enzymes consist of one subunit (Mr 30,000-40,000) or two dissimilar subunits (Mr 15,000-20,000). Previously we isolated the enzyme from human osteoclastomas, as a two-subunit protein. By Northern blotting and hybridization with radiolabelled oligonucleotides corresponding to the N-terminal sequences of the two subunits, we demonstrate here that the enzyme is transcribed as one mRNA which is translated in vitro to produce a single polypeptide of approx. Mr 33,000. Transcription as a single mRNA species is also the case in other tissues. These results suggest that the osteoclastoma enzyme undergoes post-translational modification in the form of cleavage of a single peptide bond to give a disulphide-bonded two-subunit protein.

scholarly journals Functional Dissociation of the Basolateral Transcytotic Compartment from the Apical Phago-lysosomal Compartment in Human Osteoclasts

2005 ◽  
Vol 53 (5) ◽  
pp. 665-670 ◽  
Author(s):  
James Meagher ◽  
René Zellweger ◽  
Luis Filgueira
Keyword(s):  
Staphylococcus Aureus ◽  
Dendritic Cells ◽  
Acid Phosphatase ◽  
In Vitro Study ◽  
Infectious Agent ◽  
Tartrate Resistant Acid Phosphatase ◽  
Lysosomal Compartment ◽  
Acidic Compartment ◽  
Human Osteoclasts

Tartrate-resistant acid phosphatase (TRAP) is essential for elimination of Staphylococcus aureus, the main infectious agent responsible for osteomyelitis. This in vitro study investigated uptake and processing of fluorescence-labeled S. aureus by human osteoclasts and dendritic cells. The cells were stained for TRAP and the acidic compartment using a fluorescence-based protocol. In dendritic cells, TRAP and bacteria were colocalized. In osteoclasts, there was no colocalization of bacteria, TRAP, or the acidic compartment, indicating that there are three distinct vesicular compartments: the apical phago-lysosomal compartment, the basal secretory compartment, and the basolateral transcytotic compartment. Dissociation of the TRAP-containing transcytotic vesicles from the apical phago-lysosomal compartment may restrain osteoclasts from eliminating S. aureus.

scholarly journals Reduced Granule Cell Proliferation and Molecular Dysregulation in the Cerebellum of Lysosomal Acid Phosphatase 2 (ACP2) Mutant Mice

2021 ◽  
Vol 22 (6) ◽  
pp. 2994
Author(s):  
Xiaodan Jiao ◽  
Maryam Rahimi Balaei ◽  
Ejlal Abu-El-Rub ◽  
Filippo Casoni ◽  
Hassan Pezeshgi Modarres ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Acid Phosphatase ◽  
Granule Cell ◽  
Granule Cells ◽  
Mutant Mice ◽  
Lysosomal Acid ◽  
Protein Synthesis Machinery

Lysosomal acid phosphatase 2 (Acp2) mutant mice (naked-ataxia, nax) have a severe cerebellar cortex defect with a striking reduction in the number of granule cells. Using a combination of in vivo and in vitro immunohistochemistry, Western blotting, BrdU assays, and RT-qPCR, we show downregulation of MYCN and dysregulation of the SHH signaling pathway in the nax cerebellum. MYCN protein expression is significantly reduced at P10, but not at the peak of proliferation at around P6 when the number of granule cells is strikingly reduced in the nax cerebellum. Despite the significant role of the SHH–MycN pathway in granule cell proliferation, our study suggests that a broader molecular pathway and additional mechanisms regulating granule cell development during the clonal expansion period are impaired in the nax cerebellum. In particular, our results indicate that downregulation of the protein synthesis machinery may contribute to the reduced number of granule cells in the nax cerebellum.

scholarly journals Influence of Cu2+ on Osteoclast Formation and Activity In Vitro

2021 ◽  
Vol 22 (5) ◽  
pp. 2451
Author(s):  
Anne Bernhardt ◽  
Jana Bacova ◽  
Uwe Gbureck ◽  
Michael Gelinsky
Keyword(s):  
Gene Expression ◽  
Enzyme Activities ◽  
Bone Matrix ◽  
Antimicrobial Properties ◽  
Osteoclast Formation ◽  
Tartrate Resistant Acid Phosphatase ◽  
Specific Enzyme ◽  
Cytotoxic Effects ◽  
Resorptive Activity

Background: Copper-containing biomaterials are increasingly applied for bone regeneration due to their pro-angiogenetic, pro-osteogenetic and antimicrobial properties. Therefore, the effect of Cu2+ on osteoclasts, which play a major role in bone remodeling was studied in detail. Methods: Human primary osteoclasts, differentiated from human monocytes were differentiated or cultivated in the presence of Cu2+. Osteoclast formation and activity were analyzed by measurement of osteoclast-specific enzyme activities, gene expression analysis and resorption assays. Furthermore, the glutathione levels of the cells were checked to evaluate oxidative stress induced by Cu2+. Results: Up to 8 µM Cu2+ did not induce cytotoxic effects. Activity of tartrate-resistant acid phosphatase (TRAP) was significantly increased, while other osteoclast specific enzyme activities were not affected. However, gene expression of TRAP was not upregulated. Resorptive activity of osteoclasts towards dentin was not changed in the presence of 8 µM Cu2+ but decreased in the presence of extracellular bone matrix. When Cu2+ was added to mature osteoclasts TRAP activity was not increased and resorption decreased only moderately. The glutathione level of both differentiating and mature osteoclasts was significantly decreased in the presence of Cu2+. Conclusions: Differentiating and mature osteoclasts react differently to Cu2+. High TRAP activities are not necessarily related to high resorption.

scholarly journals OC_Finder: A deep learning-based software for osteoclast segmentation, counting, and classification

2021 ◽  
Author(s):  
Xiao Wang ◽  
Mizuho Kittaka ◽  
Yilin He ◽  
Yiwei Zhang ◽  
Yasuyoshi Ueki ◽  
...  
Keyword(s):  
Deep Learning ◽  
Bone Matrix ◽  
Osteoclast Formation ◽  
Precursor Cells ◽  
Automated System ◽  
Tartrate Resistant Acid Phosphatase ◽  
Specific Cell ◽  
Microscopic Images ◽  
Multinucleated Cells

Osteoclasts are multinucleated cells that exclusively resorb bone matrix proteins and minerals on the bone surface. They differentiate from monocyte/macrophage-lineage cells in the presence of osteoclastogenic cytokines such as the receptor activator of nuclear factor-κB ligand (RANKL) and are stained positive for tartrate-resistant acid phosphatase (TRAP). In vitro, osteoclast formation assays are commonly used to assess the capacity of osteoclast precursor cells for differentiating into osteoclasts wherein the number of TRAP-positive multinucleated cells are counted as osteoclasts. Osteoclasts are manually identified on cell culture dishes by human eyes, which is a labor-intensive process. Moreover, the manual procedure is not objective and result in lack of reproducibility. To accelerate the process and reduce the workload for counting the number of osteoclasts, we developed OC_Finder, a fully automated system for identifying osteoclasts in microscopic images. OC_Finder consists of segmentation and classification steps. OC_Finder detected osteoclasts differentiated from wild-type and Sh3bp2KI/+ precursor cells at a 99.4% accuracy for segmentation and at a 98.1% accuracy for classification. The number of osteoclasts classified by OC_Finder was at the same accuracy level with manual counting by a human expert. Together, successful development of OC_Finder suggests that deep learning is a useful tool to perform prompt and accurate unbiased classification and detection of specific cell types in microscopic images.

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