scholarly journals Role of Osteoglycin in the Linkage between Muscle and Bone

2012 ◽  
Vol 287 (15) ◽  
pp. 11616-11628 ◽  
Author(s):  
Ken-ichiro Tanaka ◽  
Erika Matsumoto ◽  
Yoshiko Higashimaki ◽  
Takenobu Katagiri ◽  
Toshitsugu Sugimoto ◽  
...  

The interaction between muscle tissues and bone metabolism is incompletely understood. We hypothesized that there might be some humoral factors that are produced in muscle tissues and exhibit bone anabolic activity. We, therefore, performed comparative DNA microarray analysis between mouse myoblastic C2C12 cells transfected with either stable empty vector or ALK2 (R206H), the mutation that constitutively activates the bone morphogenetic protein (BMP) receptor, to search for muscle-derived bone anabolic factors. Twenty-five genes whose expression was decreased to <1/4, were identified; these included osteoglycin (OGN). Stable overexpression of OGN significantly decreased the levels of Runx2 and Osterix mRNA compared with those in cells transfected with vector alone in MC3T3-E1 cells. On the other hand, it significantly enhanced the levels of alkaline phosphatase (ALP), type I collagen (Col1), and osteocalcin (OCN) mRNA as well as β-catenin and mineralization. A reduction in endogenous OGN level showed the opposite effects to those of OGN overexpression in MC3T3-E1 and mouse calvarial osteoblastic cells. Transient OGN overexpression significantly suppressed the levels of Runx2, Osterix, ALP, Col1, and OCN mRNA induced by BMP-2 in C2C12 cells. The conditioned medium from OGN-overexpressed and OGN-suppressed myoblastic cells enhanced and decreased, respectively, the levels of ALP, Col1, and β-catenin in MC3T3-E1 cells. Moreover, OGN increased Smad3/4-responsive transcriptional activity as well as Col1 mRNA levels independently of endogenous TGF-β in these cells. In conclusion, this study suggests that OGN may be a crucial humoral bone anabolic factor that is produced by muscle tissues.

2021 ◽  
Vol 25 (5) ◽  
pp. 445-455
Author(s):  
Naohiro Takahashi ◽  
Hiroaki Kikuchi ◽  
Ayaka Usui ◽  
Taisuke Furusho ◽  
Takuya Fujimaru ◽  
...  

Abstract Background Lipid-metabolizing enzymes and their metabolites affect inflammation and fibrosis, but their roles in chronic kidney disease (CKD) have not been completely understood. Methods To clarify their role in CKD, we measured the mRNA levels of major lipid-metabolizing enzymes in 5/6 nephrectomized (Nx) kidneys of C57BL/6 J mice. Mediator lipidomics was performed to reveal lipid profiles of CKD kidneys. Results In 5/6 Nx kidneys, both mRNA and protein levels of Alox15 were higher when compared with those in sham kidneys. With respect to in situ hybridization, the mRNA level of Alox15 was higher in renal tubules of 5/6 Nx kidneys. To examine the role of Alox15 in CKD pathogenesis, we performed 5/6 Nx on Alox15−/− mice. Alox15−/− CKD mice exhibited better renal functions than wild-type mice. Interstitial fibrosis was also inhibited in Alox15−/− CKD mice. Mediator lipidomics revealed that Alox15−/− CKD mouse kidneys had significantly higher levels of PGD2 than the control. To investigate the effects of PGD2 on renal fibrosis, we administered PGD2 to TGF-β1-stimulated NRK-52E cells and HK-2 cells, which lead to a dose-dependent suppression of type I collagen and αSMA in both cell lines. Conclusion Increased PGD2 in Alox15−/− CKD mouse kidneys could inhibit fibrosis, thereby resulting in CKD improvement. Thus, Alox15 inhibition and PGD2 administration may be novel therapeutic targets for CKD.


2003 ◽  
Vol 82 (1) ◽  
pp. 23-27 ◽  
Author(s):  
M. Zhao ◽  
J.E. Berry ◽  
M.J. Somerman

As an approach for improving the outcome and predictability of periodontal regenerative therapies, we have focused on determining the responses of cells within the local environment to putative regenerative factors. This study examined the effects of bone morphogenetic protein-2 (BMP-2) on murine cementoblasts in vitro. Northern blot analysis indicated that BMP-2 decreased mRNA levels of bone sialoprotein and type I collagen dose-dependently (10–300 ng/mL). At low doses, up to 100 ng/mL, BMP-2 had no effect on transcripts for osteocalcin and osteopontin, whereas at 300 ng/mL, BMP-2 greatly increased expression of these two genes. BMP-2 also inhibited cementoblast-mediated mineral nodule formation in a dose-dependent manner (inhibition was noted at 10 ng/mL). Noggin reversed the effects of BMP-2 on gene expression and on mineralization. These findings reflect the diverse responses of periodontal cells to BMP-2 and highlight the need to consider the complexity of factors involved in designing predictable regenerative therapies.


Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1046
Author(s):  
Jorge Martinez ◽  
Patricio C. Smith

Desmoplastic tumors correspond to a unique tissue structure characterized by the abnormal deposition of extracellular matrix. Breast tumors are a typical example of this type of lesion, a property that allows its palpation and early detection. Fibrillar type I collagen is a major component of tumor desmoplasia and its accumulation is causally linked to tumor cell survival and metastasis. For many years, the desmoplastic phenomenon was considered to be a reaction and response of the host tissue against tumor cells and, accordingly, designated as “desmoplastic reaction”. This notion has been challenged in the last decades when desmoplastic tissue was detected in breast tissue in the absence of tumor. This finding suggests that desmoplasia is a preexisting condition that stimulates the development of a malignant phenotype. With this perspective, in the present review, we analyze the role of extracellular matrix remodeling in the development of the desmoplastic response. Importantly, during the discussion, we also analyze the impact of obesity and cell metabolism as critical drivers of tissue remodeling during the development of desmoplasia. New knowledge derived from the dynamic remodeling of the extracellular matrix may lead to novel targets of interest for early diagnosis or therapy in the context of breast tumors.


2021 ◽  
Vol 41 ◽  
pp. 100959
Author(s):  
Long-Jie Yan ◽  
Le-Chang Sun ◽  
Kai-Yuan Cao ◽  
Yu-Lei Chen ◽  
Ling-Jing Zhang ◽  
...  

Biopolymers ◽  
1979 ◽  
Vol 18 (12) ◽  
pp. 3005-3014 ◽  
Author(s):  
Donald L. Helseth ◽  
Joseph H. Lechner ◽  
Arthur Veis

2014 ◽  
Vol 9 (11) ◽  
pp. 1030-1036 ◽  
Author(s):  
Yaqiu Lin ◽  
Yanying Zhao ◽  
Ruiwen Li ◽  
Jiaqi Gong ◽  
Yucai Zheng ◽  
...  

AbstractPGC-1α has been implicated as an important mediator of functional capacity of skeletal muscle. However, the role of PGC-1α in myoblast differentiation remains unexplored. In the present study, we observed a significant up-regulation of PGC-1α expression during the differentiation of murine C2C12 myoblast. To understand the biological significance of PGC-1α up-regulation in myoblast differentiation, C2C12 cells were transfected with murine PGC-1α cDNA and siRNA targeting PGC-1α, respectively. PGC-1α over-expressing clones fused to form typical myotubes with higher mRNA level of myosin heavy chain isoform I (MyHCI) and lower MyHCIIX. No obvious differentiation was observed in PGC-1α-targeted siRNA-transfected cells with marked decrement of mRNA levels of MyHCI and MyHCIIX. Furthermore, PGC-1α increased the expression of MyoD and MyoG in C2C12 cells, which controlled the commitment of precursor cells to myotubes. These results indicate that PGC-1α is associated with myoblast differentiation and elevates MyoD and MyoG expression levels in C2C12 cells.


2010 ◽  
Vol 5 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Christian Leli ◽  
Leonella Pasqualini ◽  
Gaetano Vaudo ◽  
Stefano Gaggioli ◽  
Anna Maria Scarponi ◽  
...  

1987 ◽  
Vol 87 (2) ◽  
pp. 357-362
Author(s):  
J. Gavrilovic ◽  
R.M. Hembry ◽  
J.J. Reynolds ◽  
G. Murphy

A specific antiserum to purified rabbit tissue inhibitor of metalloproteinases (TIMP) was raised in sheep, characterized and used to investigate the role of TIMP in a model system. Chondrocytes and endothelial cells cultured on 14C-labelled type I collagen films and stimulated to produce collagenase were unable to degrade the films unless the anti-TIMP antibody was added. The degradation induced was inhibited by a specific anti-rabbit collagenase antibody. It was concluded that TIMP is a major regulatory factor in cell-mediated collagen degradation.


1991 ◽  
Vol 11 (1) ◽  
pp. 47-54
Author(s):  
H Chan ◽  
S Hartung ◽  
M Breindl

We have studied the role of DNA methylation in repression of the murine alpha 1 type I collagen (COL1A1) gene in Mov13 fibroblasts. In Mov13 mice, a retroviral provirus has inserted into the first intron of the COL1A1 gene and blocks its expression at the level of transcriptional initiation. We found that regulatory sequences in the COL1A1 promoter region that are involved in the tissue-specific regulation of the gene are unmethylated in collagen-expressing wild-type fibroblasts and methylated in Mov13 fibroblasts, confirming and extending earlier observations. To directly assess the role of DNA methylation in the repression of COL1A1 gene transcription, we treated Mov13 fibroblasts with the demethylating agent 5-azacytidine. This treatment resulted in a demethylation of the COL1A1 regulatory sequences but failed to activate transcription of the COL1A1 gene. Moreover, the 5-azacytidine treatment induced a transcription-competent chromatin structure in the retroviral sequences but not in the COL1A1 promoter. In DNA transfection and microinjection experiments, we found that the provirus interfered with transcriptional activity of the COL1A1 promoter in Mov13 fibroblasts but not in Xenopus laevis oocytes. In contrast, the wild-type COL1A1 promoter was transcriptionally active in Mov13 fibroblasts. These experiments showed that the COL1A1 promoter is potentially transcriptionally active in the presence of proviral sequences and that Mov13 fibroblasts contain the trans-acting factors required for efficient COL1A1 gene expression. Our results indicate that the provirus insertion in Mov13 can inactivate COL1A1 gene expression at several levels. It prevents the developmentally regulated establishment of a transcription-competent methylation pattern and chromatin structure of the COL1A1 domain and, in the absence of DNA methylation, appears to suppress the COL1A1 promoter in a cell-specific manner, presumably by assuming a dominant chromatin structure that may be incompatible with transcriptional activity of flanking cellular sequences.


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