ALK2 R206H Mutation Linked to Fibrodysplasia Ossificans Progressiva Confers Constitutive Activity to the BMP Type I Receptor and Sensitizes Mesenchymal Cells to BMP-Induced Osteoblast Differentiation and Bone Formation

Recent advances in materials science and biotechnology have given birth to the new and exciting field of tissue engineering, in which the two normally disparate fields are merging into a profitable matrimony. In particular the use of biomaterials capable of initiating new bone formation via a process called osteoinduction is leading to quantum leaps for the tissue engineering of bone.The classic work of Marshall R. Urist and A. Hari Reddi opened the field of osteoinductive biomaterials. Urist discovered that, upon implantation of devitalized, demineralized bone matrix in the muscle of experimental animals, new bone formation occurs within two weeks, a phenomenon he described as bone formation by induction. The tissue response elicited by implantation of demineralized bone matrix in muscle or under the skin includes activation and migration of undifferentiated mesenchymal cells by chemotaxis, anchoragedependent cell attachment to the matrix, mitosis and proliferation of mesenchymal cells, differentiation of cartilage, mineralization of the cartilage, vascular invasion of the cartilage, differentiation of osteoblasts and deposition of bone matrix, and finally mineralization of bone and differentiation of marrow in the newly developed ossicle.The osteoinductive ability of the extracellular matrix of bone is abolished by the dissociative extraction of the demineralized matrix, but is recovered when the extracted component, itself inactive, is reconstituted with the inactive residue—mainly insoluble collagenous bone matrix. This important experiment showed that the osteoinductive signal resides in the solubilized component but needs to be reconstituted with an appropriate carrier to restore the osteoinductive activity. In this case, the carrier is the insoluble collagenous bone matrix—mainly crosslinked type I collagen.

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The Effect of the Combination of Vitamin K2 and Genistein, Coumestrol and Daidzein on the Osteoblast Differentiation and Bone Matrix Formation

Journal of Biotechnology Research Center ◽

10.24126/jobrc.2016.10.2.474 ◽

2016 ◽

Vol 10 (2) ◽

pp. 12-19

Author(s):

Sahar S. Karieb ◽

Mohammed M. Jawad ◽

Hanady S. Al-Shmgani ◽

Zahraa H.M. Kadri

Keyword(s):

Bone Formation ◽

Osteoblast Differentiation ◽

Nuclear Factor Kappa B ◽

Type I Collagen ◽

Bone Mineralization ◽

Bone Matrix ◽

Vitamin K2 ◽

Type I ◽

Nuclear Factor ◽

Effective Factor

Multiple studies have been reported the stimulatory effect of the combinations of nutrients factors on bone formation. One such factor is vitamin K2 which can be associated with bone protective activities. The effect of vitamin K2 alone and in combination with genistein, coumestrol and daidzein on osteoblast differentiation and mineralization were tested. Significantly, vitamin K2 increased bone mineralization in combination with genistein (10-5M), coumestrol (10-7M) and daidzein (10-5M). However, there is no additive effect of this vitamin on alkaline phosphatase (ALP) levels in osteoblasts. By contrast, vitamin K2 enhanced the stimulatory effect of type I collagen and osteocalcin expression. Vitamin K2 alone increased RUNX and OSX expression while there is no synergistic effect with tested compound; this vitamin also did not modulate nuclear factor kappa B ligand (RANKL)/ osteoprotegerin (OPG) ratio expression. These results suggested that vitamin K2 can be more effective factor in the presence of phytoestrogens on the improvement of bone formation after menopause.

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The unique activity of bone morphogenetic proteins in bone: a critical role of the Smad signaling pathway

Biological Chemistry ◽

10.1515/hsz-2012-0310 ◽

2013 ◽

Vol 394 (6) ◽

pp. 703-714 ◽

Cited By ~ 40

Author(s):

Takenobu Katagiri ◽

Sho Tsukamoto

Keyword(s):

Skeletal Muscle ◽

Transcription Factors ◽

Bone Formation ◽

Bone Morphogenetic Proteins ◽

Fibrodysplasia Ossificans Progressiva ◽

Type I ◽

Heterotopic Bone ◽

Heterotopic Bone Formation ◽

Smad Signaling ◽

Smad Signaling Pathway

Abstract Bone morphogenetic proteins (BMPs) are multifunctional cytokines that belong to the transforming growth factor-β family. BMPs were originally identified based on their unique activity, inducing heterotopic bone formation in skeletal muscle. This unique BMP activity is transduced by specific type I and type II transmembrane kinase receptors. Among the downstream pathways activated by these receptors, the Smad1/5/8 transcription factors appear to play critical roles in BMP activity. Smad1/5/8 transcription factors are phosphorylated at the C-terminal SVS motif by BMP type I receptors and then induce the transcription of early BMP-responsive genes by binding to conserved sequences in their enhancer regions. The linker regions of Smad1/5/8 contain multiple kinase phosphorylation sites, and phosphorylation and dephosphorylation of these sites regulate the transcriptional activity of Smad proteins. Gain-of-function mutations in one BMP type I receptor have been identified in patients with fibrodysplasia ossificans progressiva, a rare genetic disorder that is characterized by progressive heterotopic bone formation in the skeletal muscle. The mutant receptors activate the Smad signaling pathway even in the absence of BMPs, therefore novel inhibitors for the BMP receptor – Smad axis are being developed to prevent heterotopic bone formation in fibrodysplasia ossificans progressiva. Taken together, the data in the literature show that the BMP type I receptor – Smad signaling axis is the critical pathway for the unique activity of BMPs and is a potential therapeutic target for pathological conditions caused by inappropriate BMP activity.

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Challenges and Opportunities for Drug Repositioning in Fibrodysplasia Ossificans Progressiva

Biomedicines ◽

10.3390/biomedicines9020213 ◽

2021 ◽

Vol 9 (2) ◽

pp. 213

Author(s):

Francesc Ventura ◽

Eleanor Williams ◽

Makoto Ikeya ◽

Alex N. Bullock ◽

Peter ten Dijke ◽

...

Keyword(s):

Bone Formation ◽

Molecular Mechanisms ◽

Drug Repositioning ◽

Point Mutations ◽

Activin A ◽

In Vitro Models ◽

Fibrodysplasia Ossificans Progressiva ◽

Endochondral Bone Formation ◽

Type I

Fibrodysplasia ossificans progressiva (FOP) is an ultrarare congenital disease that progresses through intermittent episodes of bone formation at ectopic sites. FOP patients carry heterozygous gene point mutations in activin A receptor type I ACVR1, encoding the bone morphogenetic protein (BMP) type I serine/threonine kinase receptor ALK2, termed activin receptor-like kinase (ALK)2. The mutant ALK2 displays neofunctional responses to activin, a closely related BMP cytokine that normally inhibits regular bone formation. Moreover, the mutant ALK2 becomes hypersensitive to BMPs. Both these activities contribute to enhanced ALK2 signalling and endochondral bone formation in connective tissue. Being a receptor with an extracellular ligand-binding domain and intrinsic intracellular kinase activity, the mutant ALK2 is a druggable target. Although there is no approved cure for FOP yet, a number of clinical trials have been recently initiated, aiming to identify a safe and effective treatment for FOP. Among other targeted approaches, several repurposed drugs have shown promising results. In this review, we describe the molecular mechanisms underlying ALK2 mutation-induced aberrant signalling and ectopic bone formation. In addition, we recapitulate existing in vitro models to screen for novel compounds with a potential application in FOP. We summarize existing therapeutic alternatives and focus on repositioned drugs in FOP, at preclinical and clinical stages.

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Aesculetin Promotes Osteoblastogenic Bone Formation Through Enhancing Osteoblast Differentiation and Mineralization

Current Developments in Nutrition ◽

10.1093/cdn/nzab037_060 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 350-350

Author(s):

WooJin Na ◽

Young-Hee Kang

Keyword(s):

Bone Resorption ◽

Bone Formation ◽

Osteoblast Differentiation ◽

Osteoblastic Differentiation ◽

Alizarin Red S ◽

Type I ◽

Mineral Density ◽

Alizarin Red ◽

Alp Activity ◽

Cellular Expression

Abstract Objectives Osteoporosis is a common chronic disease elicited by imbalance between osteoblastic bone formation and osteoclastic bone resorption. Marked increase in bone resorption leads to the aberrant fall in bone mineral density. With increasing age, there is also a significant reduction in bone formation. Aesculetin, a derivative of coumarin, possesses anti-inflammatory and antioxidant effects. The purpose of this study was to identify that aesculetin accelerated bone formation through increased osteoblastic differentiation and mineralization. Methods MC3T3-E1 cells were cultured with 1–10 μM aesculetin in α-MEM supplemented with 10 mM β-glycerophosphate, 50 μg/ml ascorbic acid and 10 μM dexamethasone for up to 21 days. Alkaline phosphatase (ALP) activity and staining, Alizarin red S staining, and Western blotting for induction of target proteins were conducted for the measurement of osteoblastic differentiation and mineralization. Results Aesculetin further enhanced the ALP activity of differentiated MC3T3-E1 cells, showing that aesculetin stimulated the osteoblast differentiation. Alizarin red S staining revealed that calcium deposits highly increased in 1–10 μM aesculetin-treated osteoblasts. In addition, aesculetin further increased cellular expression of the bone-forming markers of bone morphogenetic protein-2, osteopontin and collagen type I in osteoblasts. Conclusions Aesculetin was effective in enhancing osteoblast differentiation and bone mineralization for bone formation, indicating that this compound may be a potential agent for the treatment of osteoporosis. Funding Sources This work was supported by the BK21 FOUR(Fostering Outstanding Universities for Research, 4220200913807) funded by the National Research Foundation of Korea (NRF).

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Neofunction of ACVR1 in fibrodysplasia ossificans progressiva

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1510540112 ◽

2015 ◽

Vol 112 (50) ◽

pp. 15438-15443 ◽

Cited By ~ 128

Author(s):

Kyosuke Hino ◽

Makoto Ikeya ◽

Kazuhiko Horigome ◽

Yoshihisa Matsumoto ◽

Hayao Ebise ◽

...

Keyword(s):

Bone Formation ◽

Endochondral Ossification ◽

Point Mutations ◽

Activin A ◽

Bmp Signaling ◽

Fibrodysplasia Ossificans Progressiva ◽

Type I ◽

Induced Pluripotent

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease characterized by extraskeletal bone formation through endochondral ossification. FOP patients harbor point mutations in ACVR1 (also known as ALK2), a type I receptor for bone morphogenetic protein (BMP). Two mechanisms of mutated ACVR1 (FOP-ACVR1) have been proposed: ligand-independent constitutive activity and ligand-dependent hyperactivity in BMP signaling. Here, by using FOP patient-derived induced pluripotent stem cells (FOP-iPSCs), we report a third mechanism, where FOP-ACVR1 abnormally transduces BMP signaling in response to Activin-A, a molecule that normally transduces TGF-β signaling but not BMP signaling. Activin-A enhanced the chondrogenesis of induced mesenchymal stromal cells derived from FOP-iPSCs (FOP-iMSCs) via aberrant activation of BMP signaling in addition to the normal activation of TGF-β signaling in vitro, and induced endochondral ossification of FOP-iMSCs in vivo. These results uncover a novel mechanism of extraskeletal bone formation in FOP and provide a potential new therapeutic strategy for FOP.

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Overexpression of Cbfa1 in osteoblasts inhibits osteoblast maturation and causes osteopenia with multiple fractures

The Journal of Cell Biology ◽

10.1083/jcb.200105052 ◽

2001 ◽

Vol 155 (1) ◽

pp. 157-166 ◽

Cited By ~ 305

Author(s):

Wenguang Liu ◽

Satoru Toyosawa ◽

Tatsuya Furuichi ◽

Naoko Kanatani ◽

Carolina Yoshida ◽

...

Keyword(s):

Bone Formation ◽

Transgenic Mice ◽

Cortical Bone ◽

Osteoblast Differentiation ◽

Type I Collagen ◽

In Vivo Studies ◽

Type I ◽

Multiple Fractures ◽

Matrix Production

Targeted disruption of core binding factor α1 (Cbfa1) showed that Cbfa1 is an essential transcription factor in osteoblast differentiation and bone formation. Furthermore, both in vitro and in vivo studies showed that Cbfa1 plays important roles in matrix production and mineralization. However, it remains to be clarified how Cbfa1 controls osteoblast differentiation, bone formation, and bone remodelling. To understand fully the physiological functions of Cbfa1, we generated transgenic mice that overexpressed Cbfa1 in osteoblasts using type I collagen promoter. Unexpectedly, Cbfa1 transgenic mice showed osteopenia with multiple fractures. Cortical bone, which was thin, porous, and enriched with osteopontin, was invaded by osteoclasts, despite the absence of acceleration of osteoclastogenesis. Although the number of neonatal osteoblasts was increased, their function was impaired in matrix production and mineralization. Furthermore, terminally differentiated osteoblasts, which strongly express osteocalcin, and osteocytes were diminished greatly, whereas less mature osteoblasts expressing osteopontin accumulated in adult bone. These data indicate that immature organization of cortical bone, which was caused by the maturational blockage of osteoblasts, led to osteopenia and fragility in transgenic mice, demonstrating that Cbfa1 inhibits osteoblast differentiation at a late stage.

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Faculty Opinions recommendation of A recurrent mutation in the BMP type I receptor ACVR1 causes inherited and sporadic fibrodysplasia ossificans progressiva.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13815.471313 ◽

2006 ◽

Author(s):

Andrew Arnold

Keyword(s):

Recurrent Mutation ◽

Fibrodysplasia Ossificans Progressiva ◽

Type I

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Conditional knockout of the PDK‐1 gene in osteoblasts affects osteoblast differentiation and bone formation

Journal of Cellular Physiology ◽

10.1002/jcp.30249 ◽

2020 ◽

Author(s):

Yiguang Bai ◽

Qiong Zhang ◽

Qiaoling Chen ◽

Quan Zhou ◽

Yanan Zhang ◽

...

Keyword(s):

Bone Formation ◽

Osteoblast Differentiation ◽

Conditional Knockout

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Serum levels of bone formation and resorption markers in relation to vitamin D status in professional gymnastics and physically active men during upper and lower body high-intensity exercise

Journal of the International Society of Sports Nutrition ◽

10.1186/s12970-021-00430-8 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Jan Mieszkowski ◽

Andrzej Kochanowicz ◽

Elżbieta Piskorska ◽

Bartłomiej Niespodziński ◽

Joanna Siódmiak ◽

...

Keyword(s):

Vitamin D ◽

Bone Formation ◽

Bone Turnover ◽

Bone Turnover Markers ◽

Type I Collagen ◽

Serum Levels ◽

Type I ◽

Vitamin D Metabolites ◽

Physically Active ◽

Turnover Markers

Abstract Purpose/introduction To compare serum levels of bone turnover markers in athletes and non-athletes, and to evaluate the relationship between serum levels of vitamin D metabolites and exercise-induced changes in biomarker levels. Methods Sixteen elite male artistic gymnasts (EG; 21.4 ± 0.8 years-old) and 16 physically active men (the control group, PAM; 20.9 ± 1.2 years-old) performed lower and upper body 30-s Wingate anaerobic tests (LBWT and UBWT, respectively). For biomarker analysis, blood samples were collected before, and 5 and 30 min after exercise. Samples for vitamin D levels were collected before exercise. N-terminal propeptide of type I collagen (PINP) was analysed as a marker of bone formation. C-terminal telopeptide of type I collagen (CTX) was analysed as a marker of bone resorption. Results UBWT fitness readings were better in the EG group than in the PAM group, with no difference in LBWT readings between the groups. UBWT mean power was 8.8% higher in subjects with 25(OH)D3 levels over 22.50 ng/ml and in those with 24,25(OH)2D3 levels over 1.27 ng/ml. Serum CTX levels increased after both tests in the PAM group, with no change in the EG group. PINP levels did not change in either group; however, in PAM subjects with 25(OH)D3 levels above the median, they were higher than those in EG subjects. Conclusion Vitamin D metabolites affect the anaerobic performance and bone turnover markers at rest and after exercise. Further, adaptation to physical activity modulates the effect of anaerobic exercise on bone metabolism markers.

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