scholarly journals Aberrant BMP2 Signaling in Patients Diagnosed with Osteoporosis

2020 ◽  
Vol 21 (18) ◽  
pp. 6909 ◽  
Author(s):  
Hilary W. Durbano ◽  
Daniel Halloran ◽  
John Nguyen ◽  
Victoria Stone ◽  
Sean McTague ◽  
...  

The most common bone disease in humans is osteoporosis (OP). Current therapeutics targeting OP have several negative side effects. Bone morphogenetic protein 2 (BMP2) is a potent growth factor that is known to activate both osteoblasts and osteoclasts. It completes these actions through both SMAD-dependent and SMAD-independent signaling. A novel interaction between the BMP type Ia receptor (BMPRIa) and casein kinase II (CK2) was discovered, and several CK2 phosphorylation sites were identified. A corresponding blocking peptide (named CK2.3) was designed to further elucidate the phosphorylation site’s function. Previously, CK2.3 demonstrated an increased osteoblast activity and decreased osteoclast activity in a variety of animal models, cell lines, and isolated human osteoblasts. It is hypothesized that CK2.3 completes these actions through the BMP signaling pathway. Furthermore, it was recently discovered that BMP2 did not elicit an osteogenic response in osteoblasts from patients diagnosed with OP, while CK2.3 did. In this study, we explore where in the BMP pathway the signaling disparity or defect lies in those diagnosed with OP. We found that osteoblasts isolated from patients diagnosed with OP did not activate SMAD or ERK signaling after BMP2 stimulation. When OP osteoblasts were stimulated with BMP2, both BMPRIa and CK2 expression significantly decreased. This indicates a major disparity within the BMP signaling pathway in patients diagnosed with osteoporosis.

2020 ◽  
Vol 10 (12) ◽  
pp. 1884-1890
Author(s):  
Jing Tian ◽  
Qianying Zhao ◽  
Dapeng Zhou ◽  
Bing Xie

The balance of osteoblasts and osteoclasts is critical for bone formation and remodeling and imbalance causes osteoporosis (OP). TGF-β regulates bone tissue repair and regeneration, but TGF-β’s role in osteogenesis in OP has not been elucidated. OVX-induced OP rat models were constructed and rat BMSCs were isolated and assigned into control group, OP group, and TGF-β group (transfected with TGF-β1 plasmid followed by analysis of cell proliferation by MTT assay, RUNX2 and OPN expression by Real time PCR, ALP activity and secretion of TGF-β, BMP-2 and BMP-9 by ELISA. In addition, RANKL was added to induce BMSCs differentiation into to osteoclasts which were transfected with TGF-β1 followed by analysis of cell proliferation, c-Fos and TRAP expression and secretion of BMP-2 and BMP-9. OP group rats had significantly reduced secretion of TGF-β1, BMP-2 and BMP-9, reduced cell proliferation, decreased RUNX2 and OPN expression and ALP activity (P <0.05). Transfection of TGF-β1 in BMSCs of OP group rats could significantly reverse the above changes (P <0.05). TGF-β1 significantly inhibited osteoclast proliferation, decreased expression of c-Fos and TRAP, and increased secretion of BMP-2 and BMP-9 (P <0.05). TGF-β1 level in OP is decreased. Up-regulating TGF-β promotes osteoblast differentiation in OP rats by regulating BMP signaling pathway, and inhibits osteoclast proliferation and differentiation.


2006 ◽  
Vol 174 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Lisa M. Hoffman ◽  
Kamal Garcha ◽  
Konstantina Karamboulas ◽  
Matthew F. Cowan ◽  
Linsay M. Drysdale ◽  
...  

The bone morphogenetic protein (BMP) and growth and differentiation factor (GDF) signaling pathways have well-established and essential roles within the developing skeleton in coordinating the formation of cartilaginous anlagen. However, the identification of bona fide targets that underlie the action of these signaling molecules in chondrogenesis has remained elusive. We have identified the gene for the retinoic acid (RA) synthesis enzyme Aldh1a2 as a principal target of BMP signaling; prochondrogenic BMPs or GDFs lead to attenuation of Aldh1a2 expression and, consequently, to reduced activation of the retinoid signaling pathway. Consistent with this, antagonism of retinoid signaling phenocopies BMP4 action, whereas RA inhibits the chondrogenic stimulatory activity of BMP4. BMP4 also down-regulates Aldh1a2 expression in organ culture and, consistent with this, Aldh1a2 is actively excluded from the developing cartilage anlagens. Collectively, these findings provide novel insights into BMP action and demonstrate that BMP signaling governs the fate of prechondrogenic mesenchyme, at least in part, through regulation of retinoid signaling.


2012 ◽  
Vol 287 (46) ◽  
pp. 38656-38664 ◽  
Author(s):  
Hara Kang ◽  
Justin Louie ◽  
Alexandra Weisman ◽  
Jessica Sheu-Gruttadauria ◽  
Brandi N. Davis-Dusenbery ◽  
...  

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Da Jin Sol Jung ◽  
Myunggi Baik

AbstractWe evaluated whether castration affects bone morphogenetic protein 2 (BMP2) level and the expression of its signaling molecules in Korean cattle bulls. We also checked whether castration affects the expression of muscle fiber type and oxidative and glycolytic enzyme genes. Enzyme-linked immunosorbent assays revealed that steers had higher plasma BMP2 and leptin concentrations than bulls. Quantitative real-time PCR showed that steers had higher mRNA levels of the lysyl oxidase gene, a downstream target of the BMP signaling pathway, in the longissimus thoracis (LT) muscle. Steers had higher adipogenic peroxisome proliferator-activated receptor gamma and lipogenic fatty acid binding protein 4 mRNA levels in the LT than bulls. Steers had lower mRNA levels for several muscle fiber type 1 genes and fiber type 2A myosin heavy chain 2 gene than bulls. Steers had higher mRNA levels of the glycolytic enzyme phosphoglycerate kinase 1 gene than bulls. Transcript levels of oxidative enzyme genes did not differ between bulls and steers. Regression analysis revealed a positive association between plasma BMP2 levels and intramuscular fat (IMF) content in the steer group. These findings suggest that upregulation of the BMP signaling pathway in response to castration induces increased adipogenic gene expression, contributing to the increased IMF deposition observed in castrated animals.


2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Jonathan W. Lowery ◽  
Brice Brookshire ◽  
Vicki Rosen

Bone morphogenetic proteins (BMPs) constitute the largest subdivision of the TGF-βfamily of ligands and are unequivocally involved in regulating stem cell behavior. Appropriate regulation of canonical BMP signaling is critical for the development and homeostasis of numerous human organ systems, as aberrations in the BMP pathway or its regulation are increasingly associated with diverse human pathologies. In this review, we provide a wide-perspective on strategies that increase or decrease BMP signaling. We briefly outline the current FDA-approved approaches, highlight emerging next-generation technologies, and postulate prospective avenues for future investigation. We also detail how activating other pathways may indirectly modulate BMP signaling, with a particular emphasis on the relationship between the BMP and Activin/TGF-βpathways.


2013 ◽  
Vol 203 (2) ◽  
pp. 345-357 ◽  
Author(s):  
Catherine E. Winbanks ◽  
Justin L. Chen ◽  
Hongwei Qian ◽  
Yingying Liu ◽  
Bianca C. Bernardo ◽  
...  

Although the canonical transforming growth factor β signaling pathway represses skeletal muscle growth and promotes muscle wasting, a role in muscle for the parallel bone morphogenetic protein (BMP) signaling pathway has not been defined. We report, for the first time, that the BMP pathway is a positive regulator of muscle mass. Increasing the expression of BMP7 or the activity of BMP receptors in muscles induced hypertrophy that was dependent on Smad1/5-mediated activation of mTOR signaling. In agreement, we observed that BMP signaling is augmented in models of muscle growth. Importantly, stimulation of BMP signaling is essential for conservation of muscle mass after disruption of the neuromuscular junction. Inhibiting the phosphorylation of Smad1/5 exacerbated denervation-induced muscle atrophy via an HDAC4-myogenin–dependent process, whereas increased BMP–Smad1/5 activity protected muscles from denervation-induced wasting. Our studies highlight a novel role for the BMP signaling pathway in promoting muscle growth and inhibiting muscle wasting, which may have significant implications for the development of therapeutics for neuromuscular disorders.


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