PERIARTICULAR GENE EXPRESSION OF OSTEOPONTIN AND PROGRESSION IN OSTEOPENIA FOLLOWING JOINT IMMOBILIZATION

2001 ◽  
Vol 05 (04) ◽  
pp. 225-234
Author(s):  
TAKAHIDE MIYAMA ◽  
NORIMASA NAKAMURA ◽  
TAKANOBU NAKASE ◽  
YUKIYOSHI TORITSUKA ◽  
AKIRA MYOUI ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Matrix ◽  
Knee Joints ◽  
Tartrate Resistant Acid Phosphatase ◽  
Positive Staining ◽  
Multinucleated Cells ◽  
Molecular Events ◽  
Bone Matrix Proteins ◽  
Temporal And Spatial

In order to elucidate the molecular events involved in periarticular osteopenia following joint immobilization, we investigated the temporal and spatial gene expression of one of the major non-collagenous bone matrix proteins, osteopontin (OPN), in periarticular regions, after immobilizing rat knee joints. Significant decreases in total BMD was observed in the immobilized limbs after 2 weeks of immobilization. Histologically, multinucleated cells with positive staining for tartrate resistant acid phosphatase (TRAP) were significantly increased in the metaphyseal regions, 1 to 4 weeks following immobilization. In situ hybridization studies revealed that OPN mRNA was present in a significantly larger number of cells in the metaphysial regions of joints immobilized for 1 to 3 weeks; compared with those levels detected in the control limbs, OPN mRNA was mainly detected in osteoblast/osteocyte-lineage cells of the spongiosa. Such temporal and spatial similarities in the expression of TRAP-positive multinucleated cells and OPN transcripts suggest the possible involvement of OPN in the periarticular osteoclastogenesis, leading to the activation of regional bone resorption following joint immobilization.

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.

Localization of the mRNA for bone matrix proteins during fracture healing as determined by in situ hybridization

2009 ◽  
Vol 9 (10) ◽  
pp. 1551-1557 ◽  
Author(s):  
Kimiaki Hirakawa ◽  
Sehchi Hirota ◽  
Tohru Ikeda ◽  
Akira Yamaguchi ◽  
Teiji Takemura ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fracture Healing ◽  
Bone Matrix ◽  
Matrix Proteins ◽  
Bone Matrix Proteins

Spaceflight results in reduced mRNA levels for tissue-specific proteins in the musculoskeletal system

1994 ◽  
Vol 266 (4) ◽  
pp. E567-E573 ◽  
Author(s):  
P. Backup ◽  
K. Westerlind ◽  
S. Harris ◽  
T. Spelsberg ◽  
B. Kline ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Formation ◽  
Musculoskeletal System ◽  
Bone Growth ◽  
Bone Matrix ◽  
Long Bone ◽  
Type I ◽  
Mrna Levels ◽  
Bone Matrix Proteins ◽  
Specific Proteins

The purpose of the present study in growing rats was to investigate the effects of short-term spaceflight on gene expression in bone and muscle and on cortical bone histomorphometry. Two experiments were carried out; Physiological Systems Experiments 1 and 2 were 4- and 10-day flights, respectively. Radial bone growth in the humerus was unchanged during the 4-day flight and decreased during the 10-day flight. Expression of mRNA for glyceraldehyde-3-phosphate dehydrogenase was unchanged in biceps, calvarial periosteum, and long-bone periosteum after spaceflight. Similarly, no changes in ribosomal RNA levels were observed in long-bone or calvarial periosteum after spaceflight. In contrast, spaceflight decreased steady-state mRNA levels for actin in muscle (4-day flight). Osteocalcin (both spaceflights) and the prepro-alpha 2[I] chain of type I precollagen (10-day flight) mRNA levels were decreased in long-bone and calvarial periosteum after spaceflight. These results indicate that the effects of spaceflight on the musculoskeletal system include decreased expression of some muscle- and bone-specific genes as well as decreased bone formation. Interestingly, detectable reductions in gene expression for bone matrix proteins preceded histological evidence for decreased bone formation.

scholarly journals Gene expression for bone matrix proteins during bone resorption in calcium-deficient rats.

1994 ◽  
Vol 64 ◽  
pp. 290
Author(s):  
Keiichi Ohya ◽  
Maki Sumikawa ◽  
Naoya Arai ◽  
Masashi Tatematsu ◽  
Hideaki Ogura
Keyword(s):  
Gene Expression ◽  
Bone Resorption ◽  
Bone Matrix ◽  
Matrix Proteins ◽  
Bone Matrix Proteins

Development of a Porcine Model to Assess the Effect of In-Situ Knee Joint Loading On Site-Specific Cartilage Gene Expression

2021 ◽  
Author(s):  
Baaba Otoo ◽  
LePing Li ◽  
David A. Hart ◽  
Walter Herzog
Keyword(s):  
Gene Expression ◽  
Mechanical Loading ◽  
Fluid Pressure ◽  
Cartilage Explants ◽  
Knee Joints ◽  
Expression Levels ◽  
Biological Responses ◽  
Loading Tests ◽  
Gene Expression Levels

Abstract Cyclic mechanical loading of cartilage induces stresses and fluid flow which are thought to modulate chondrocyte metabolism. The uneven surface, plus the heterogeneity of cartilage within a joint, makes stress and fluid pressure distribution in the tissue non-uniform, and gene expression may vary at different sites as a function of load magnitude, frequency and time. In previous studies, cartilage explants were used for loading tests to investigate biological responses of the cartilage to mechanical loading. In contrast, we used loading tests on intact knee joints, to better reflect the loading conditions in a joint, and thus provide a more physiologically relevant mechanical environment. Gene expression levels in loaded samples for a selection of relevant genes were compared with those of the corresponding unloaded control samples to characterize potential differences. Furthermore, the effect of load magnitude and duration on gene expression levels were investigated. We observed differences in gene expression levels between samples from different sites in the same joint and between corresponding samples from the same site in loaded and unloaded joints. Consistent with previous findings, our results indicate that there is a critical upper and lower threshold of loading for triggering the expression of certain genes. Variations in gene expression levels may reflect the effect of local loading, topography and structure of the cartilage in an intact joint on the metabolic activity of the associated cells.

scholarly journals In situ hybridization of bone matrix proteins in undecalcified adult rat bone sections.

1992 ◽  
Vol 40 (8) ◽  
pp. 1079-1088 ◽  
Author(s):  
T Ikeda ◽  
S Nomura ◽  
A Yamaguchi ◽  
T Suda ◽  
S Yoshiki
Keyword(s):  
In Situ Hybridization ◽  
Bone Matrix ◽  
Matrix Proteins ◽  
Adult Rat ◽  
Bone Matrix Proteins ◽  
Rat Bone
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