scholarly journals Elevated Gα11 expression in osteoblast lineage cells promotes osteoclastogenesis and leads to enhanced trabecular bone accrual in response to pamidronate

2016 ◽  
Vol 310 (10) ◽  
pp. E811-E820 ◽  
Author(s):  
Ariana Dela Cruz ◽  
Marc D. Grynpas ◽  
Jane Mitchell
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Osteoclast Formation ◽  
Osteoblastic Cells ◽  
Mineral Density ◽  
Paracrine Factors ◽  
Calcified Cartilage ◽  
Trabecular Bone Loss ◽  
G Protein Coupled ◽  
Osteoblast Lineage

Osteoblastic cells indirectly induce osteoclastogenesis in the bone microenvironment by expressing paracrine factors such as RANKL and M-CSF, leading to increased bone resorption. These cytokines can be regulated by a variety of intracellular pathways, which include G protein-coupled receptor signaling. To explore how enhanced signaling of the Gαq/11 pathway in osteoblast lineage cells may mediate osteoclast formation, we cocultured wild-type (WT) preosteoclasts with BMSCs derived from either WT or transgenic mice with osteoblast-specific overexpression of Gα11 (G11-Tg). G11-Tg cocultures had elevated osteoclast numbers with greater resorptive capacity and increased expression of Rankl, Rankl:Opg (osteoprotegerin), and M-csf compared with cocultures with WT BMSCs. As well, cocultures with G11-Tg BMSCs required a higher concentration of OPG to inhibit osteoclast formation and less angiotensin II to increase osteoclast size. These indicate that G11-Tg osteoblasts drive the increased osteoclast formation and osteopenia seen in G11-Tg mice. Pamidronate treatment of G11-Tg mice restored the trabecular bone loss phenotype, as bone mineral density, bone volume, trabecular number, separation, and expressions of osteoblastic and osteoclastic genes were comparable with WT parameters. These changes were characterized by enhanced accumulation of calcified cartilage in trabecular bone, demonstrating that resorption of the cartilaginous intermediate by osteoclasts is more affected by bisphosphonate treatment in G11-Tg mice. In conclusion, overexpression of Gα11 in osteoblastic cells promotes osteoclastogenesis by upregulation of Rankl and M-csf and bone loss by increased osteoclast resorption of the trabecular bone and cartilaginous matrix.

scholarly journals A Randomized Trial of Zoledronic Acid to Prevent Bone Loss in the First Year after Kidney Transplantation

2019 ◽  
Vol 30 (2) ◽  
pp. 355-365 ◽  
Author(s):  
Igor Denizarde Bacelar Marques ◽  
Maria Júlia Correia Lima Nepomuceno Araújo ◽  
Fabiana Giorgetti Graciolli ◽  
Luciene Machado dos Reis ◽  
Rosa Maria R. Pereira ◽  
...  
Keyword(s):  
Bone Loss ◽  
Randomized Trial ◽  
Trabecular Bone ◽  
Kidney Transplant ◽  
Quantitative Computed Tomography ◽  
First Year ◽  
Mineral Density ◽  
Post Transplant ◽  
Bone Biopsies ◽  
Trabecular Bone Loss

BackgroundBone and mineral disorders commonly affect kidney transplant (KTx) recipients and have been associated with a high risk of fracture. Bisphosphonates may prevent or treat bone loss in such patients, but there is concern that these drugs might induce adynamic bone disease (ABD).MethodsIn an open label, randomized trial to assess the safety and efficacy of zoledronate for preventing bone loss in the first year after kidney transplant, we randomized 34 patients before transplant to receive zoledronate or no treatment. We used dual-energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and bone biopsies to evaluate changes in bone in the 32 evaluable participants between the time of KTx and 12 months post-transplant.ResultsBoth groups of patients experienced decreased bone turnover after KTx, but zoledronate itself did not affect this outcome. Unlike previous studies, DXA showed no post-transplant bone loss in either group; we instead observed an increase of bone mineral density in both lumbar spine and total hip sites, with a significant positive effect of zoledronate. However, bone biopsies showed post-transplant impairment of trabecular connectivity (and no benefit from zoledronate); HR-pQCT detected trabecular bone loss at the peripheral skeleton, which zoledronate partially attenuated.ConclusionsCurrent immunosuppressive regimens do not contribute to post-transplant central skeleton trabecular bone loss, and zoledronate does not induce ABD. Because fractures in transplant recipients are most commonly peripheral fractures, clinicians should consider bisphosphonate use in patients at high fracture risk who have evidence of significantly low bone mass at these sites at the time of KTx.

scholarly journals RANKL from Bone Marrow Adipocytes Regulates Osteoclast Formation and Bone Loss in Mice

2020 ◽  
Author(s):  
Xin Zhi ◽  
Yan Hu ◽  
Xiaoqun Li ◽  
Wei Cong ◽  
Biaotong Huang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Loss ◽  
Cancellous Bone ◽  
Osteoclast Formation ◽  
Adult Mice ◽  
Conditional Deletion ◽  
Bone Marrow Adipocytes ◽  
Calcified Cartilage ◽  
Cellular Source ◽  
Trabecular Bone Loss

AbstractReceptor activator of NF-κB ligand (RANKL) is essential for osteoclast formation. The cellular source of RANKL for osteoclastogenesis has not been fully uncovered. Bone marrow (BM) adipocytes derived from bone marrow mesenchymal stromal cells (BMSCs) express RANKL. Here we demonstrated that the AdipoqCre could target bone marrow adipocytes. We crossed the AdipoqCre mice with ranklfl/fl mice to conditionally delete RANKL from BM adipocytes. Conditional deletion of RANKL increased cancellous bone mass in the long bones of growing and adult mice by reducing the formation of trabecular osteoclasts and inhibiting bone resorption but did not affect cortical bone thickness or resorption of calcified cartilage. AdipoqCre; ranklfl/fl mice exhibited resistance to estrogen deficiency and rosiglitazone (ROS) induced trabecular bone loss but showed bone loss induced by unloading. BM adipocytes therefore represent an essential source of RANKL for the formation of trabecula osteoclasts and resorption of cancellous bone during remodeling.

scholarly journals Drug-induced prevention of gastrectomy- and ovariectomy-induced osteopaenia in the young female rat

2002 ◽  
Vol 175 (3) ◽  
pp. 695-703 ◽  
Author(s):  
N Andersson ◽  
VV Surve ◽  
D Lehto-Axtelius ◽  
C Ohlsson ◽  
R Hakanson ◽  
...  
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Bone Mineral ◽  
Lumbar Vertebra ◽  
Underlying Mechanism ◽  
Female Rat ◽  
Mineral Density ◽  
Drug Induced ◽  
Ovx Rats ◽  
Trabecular Bone Loss

Both ovariectomy (Ovx) and gastrectomy (Gx) induce osteopaenia in rats and humans. While the effect of Ovx has been ascribed to oestrogen deficiency, the underlying mechanism behind Gx is poorly understood. Alendronate, oestrogen and parathyroid hormone (PTH) are known to prevent the osteopaenia induced by Ovx in rats. The purpose of the present study was to determine whether alendronate, oestrogen or PTH could also prevent Gx-evoked osteopaenia. Rats were Ovx-, Gx-, or were sham-operated (Sham) and were then treated with alendronate (50 micro g/kg/day), oestrogen (10 micro g/kg/day) or PTH(1-84) (75 micro g/kg/day) for eight weeks. At sacrifice, serum PTH was unaffected by surgery (Ovx, 64+/-8 pg/ml; Gx, 75+/-13 pg/ml; Sham, 58+/-11 pg/ml). The bone mineral density (BMD) of the fifth lumbar vertebra (L5) was analysed. Ovx and Gx reduced the BMD (ash weight/Volume) of the L5 by 15+/-4% and 22+/-3% respectively. Trabecular BMD and the cortical bone mineral content (BMC) of the femur were assessed using peripheral computed tomography. Both Ovx and Gx markedly reduced trabecular BMD in the metaphyseal area of the distal femur (Ovx, -37+/-7%; Gx, -49+/-7%). The cortical BMC of the femur was only slightly reduced. Alendronate prevented trabecular bone loss after both Ovx and Gx, while oestrogen and PTH prevented trabecular bone loss after Ovx but not after Gx. In conclusion, the bisphosphonate alendronate prevented both Ovx- and Gx-induced trabecular bone loss. In contrast, PTH and oestrogen prevented Ovx-induced but not Gx-induced trabecular bone loss, suggesting that the mechanism behind the trabecular bone loss in Ovx rats differs from that in Gx rats. The results support the notion that the mechanism of action for the bone-sparing effect of these drugs differs. The ability of alendronate, and probably also other bisphosphonates, to prevent Gx-evoked osteopaenia in the rat might be of potential clinical interest when dealing with post-Gx osteopaenia in humans.

Grizzly Bears (Ursus Arctos Horribilis) and Black Bears (Ursus Americanus) Prevent Trabecular Bone Loss During Disuse (Hibernation)

2009 ◽  
Author(s):  
Meghan E. McGee-Lawrence ◽  
Samantha J. Wojda ◽  
Lindsay N. Barlow ◽  
Alesha B. Castillo ◽  
Oran Kennedy ◽  
...  
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Ursus Arctos ◽  
Black Bears ◽  
Bone Architecture ◽  
Grizzly Bears ◽  
Mineral Density ◽  
Ursus Arctos Horribilis ◽  
Trabecular Bone Loss ◽  
Skeletal Loading

Reduced skeletal loading causes cortical and trabecular bone loss in humans and other animals, but trabecular bone responds to disuse more rapidly and shows greater losses than cortical bone for a given period of inactivity [1–2]. Manifestations of disuse on trabecular bone include unbalanced bone remodeling, decreased bone mineral density, and compromised bone architecture [3].

scholarly journals Kalkitoxin Reduces Osteoclast Formation and Resorption and Protects against Inflammatory Bone Loss

2021 ◽  
Vol 22 (5) ◽  
pp. 2303
Author(s):  
Liang Li ◽  
Ming Yang ◽  
Saroj Kumar Shrestha ◽  
Hyoungsu Kim ◽  
William H. Gerwick ◽  
...  
Keyword(s):  
Bone Loss ◽  
Transmembrane Protein ◽  
Osteoclast Differentiation ◽  
Mapk Signaling ◽  
Osteoclast Formation ◽  
Bone Diseases ◽  
Tartrate Resistant Acid Phosphatase ◽  
Nuclear Factor ◽  
Mineral Density ◽  
Multinucleated Cells

Osteoclasts, bone-specified multinucleated cells produced by monocyte/macrophage, are involved in numerous bone destructive diseases such as arthritis, osteoporosis, and inflammation-induced bone loss. The osteoclast differentiation mechanism suggests a possible strategy to treat bone diseases. In this regard, we recently examined the in vivo impact of kalkitoxin (KT), a marine product obtained from the marine cyanobacterium Moorena producens (previously Lyngbya majuscula), on the macrophage colony-stimulating factor (M-CSF) and on the receptor activator of nuclear factor κB ligand (RANKL)-stimulated in vitro osteoclastogenesis and inflammation-mediated bone loss. We have now examined the molecular mechanism of KT in greater detail. KT decreased RANKL-induced bone marrow-derived macrophages (BMMs) tartrate-resistant acid phosphatase (TRAP)-multinucleated cells at a late stage. Likewise, KT suppressed RANKL-induced pit area and actin ring formation in BMM cells. Additionally, KT inhibited several RANKL-induced genes such as cathepsin K, matrix metalloproteinase (MMP-9), TRAP, and dendritic cell-specific transmembrane protein (DC-STAMP). In line with these results, RANKL stimulated both genes and protein expression of c-Fos and nuclear factor of activated T cells (NFATc1), and this was also suppressed by KT. Moreover, KT markedly decreased RANKL-induced p-ERK1/2 and p-JNK pathways at different time points. As a result, KT prevented inflammatory bone loss in mice, such as bone mineral density (BMD) and osteoclast differentiation markers. These experiments demonstrated that KT markedly inhibited osteoclast formation and inflammatory bone loss through NFATc1 and mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, KT may have potential as a treatment for destructive bone diseases.

scholarly journals Combination treatment with pioglitazone and fenofibrate attenuates pioglitazone-mediated acceleration of bone loss in ovariectomized rats

2011 ◽  
Vol 212 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Rana Samadfam ◽  
Malaika Awori ◽  
Agnes Bénardeau ◽  
Frieder Bauss ◽  
Elena Sebokova ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Mass ◽  
Trabecular Bone ◽  
Bone Mineral ◽  
Combination Treatment ◽  
Mass Gain ◽  
Ovariectomized Rats ◽  
Concomitant Treatment ◽  
Mineral Density ◽  
Ovx Rats

Peroxisome proliferator-activated receptor (PPAR) γ agonists, such as pioglitazone (Pio), improve glycemia and lipid profile but are associated with bone loss and fracture risk. Data regarding bone effects of PPARα agonists (including fenofibrate (Feno)) are limited, although animal studies suggest that Feno may increase bone mass. This study investigated the effects of a 13-week oral combination treatment with Pio (10 mg/kg per day)+Feno (25 mg/kg per day) on body composition and bone mass parameters compared with Pio or Feno alone in adult ovariectomized (OVX) rats, with a 4-week bone depletion period, followed by a 6-week treatment-free period. Treatment of OVX rats with Pio+Feno resulted in ∼50% lower fat mass gain compared with Pio treatment alone. Combination treatment with Pio+Feno partially prevented Pio-induced loss of bone mineral content (∼45%) and bone mineral density (BMD; ∼60%) at the lumbar spine. Similar effects of treatments were observed at the femur, most notably at sites rich in trabecular bone. At the proximal tibial metaphysis, concomitant treatment with Pio+Feno prevented Pio exacerbation of ovariectomy-induced loss of trabecular bone, resulting in BMD values in the Pio+Feno group comparable to OVX controls. Discontinuation of Pio or Feno treatment of OVX rats was associated with partial reversal of effects on bone loss or bone mass gain, respectively, while values in the Pio+Feno group remained comparable to OVX controls. These data suggest that concurrent/dual agonism of PPARγ and PPARα may reduce the negative effects of PPARγ agonism on bone mass.

scholarly journals Propranolol Attenuates Risperidone-Induced Trabecular Bone Loss in Female Mice

Endocrinology ◽  
2015 ◽  
Vol 156 (7) ◽  
pp. 2374-2383 ◽  
Author(s):  
Katherine J. Motyl ◽  
Victoria E. DeMambro ◽  
Deborah Barlow ◽  
David Olshan ◽  
Kenichi Nagano ◽  
...  
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Female Mice ◽  
Trabecular Bone Loss

scholarly journals The plate-to-rod transition in trabecular bone loss is elusive

2021 ◽  
Vol 8 (6) ◽  
pp. 201401
Author(s):  
A. A. Felder ◽  
S. Monzem ◽  
R. De Souza ◽  
B. Javaheri ◽  
D. Mills ◽  
...  
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Bone Volume ◽  
Continuous Measure ◽  
Bone Volume Fraction ◽  
Trabecular Bone Loss ◽  
Mouse Tibia ◽  
Disease Stages ◽  
The Relationship

Changes in trabecular micro-architecture are key to our understanding of osteoporosis. Previous work focusing on structure model index (SMI) measurements have concluded that disease progression entails a shift from plates to rods in trabecular bone, but SMI is heavily biased by bone volume fraction. As an alternative to SMI, we proposed the ellipsoid factor (EF) as a continuous measure of local trabecular shape between plate-like and rod-like extremes. We investigated the relationship between EF distributions, SMI and bone volume fraction of the trabecular geometry in a murine model of disuse osteoporosis as well as from human vertebrae of differing bone volume fraction. We observed a moderate shift in EF median (at later disease stages in mouse tibia) and EF mode (in the vertebral samples with low bone volume fraction) towards a more rod-like geometry, but not in EF maximum and minimum. These results support the notion that the plate to rod transition does not coincide with the onset of bone loss and is considerably more moderate, when it does occur, than SMI suggests. A variety of local shapes not straightforward to categorize as rod or plate exist in all our trabecular bone samples.

scholarly journals B Cell Specific Knockdown of the Erythropoietin (EPO) Receptor Attenuates EPO-Induced Bone Loss in Mice

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 939-939
Author(s):  
Albert Kolomansky ◽  
Naamit Deshet-Unger ◽  
Nathalie Ben-Califa ◽  
Zamzam Awida ◽  
Maria Ibrahim ◽  
...  
Keyword(s):  
B Cells ◽  
Bone Loss ◽  
B Cell ◽  
Trabecular Bone ◽  
Cell Lineage ◽  
Lineage Tracing ◽  
Trabecular Bone Loss ◽  
Β3 Integrin ◽  
First Time

Background and aims: Erythropoietin (EPO) is the key regulator of red blood cell production, commonly used in clinical practice to treat certain forms of anemia. Our studies and those of others have demonstrated that EPO administration induces substantial trabecular bone loss. We proposed that EPO-induced bone loss is partially mediated by subsets of bone marrow (BM) B cells that express EPO-R. Mechanistically, EPO upregulates the surface expression of RANKL by BM B cells and augments B cell-derived osteoclastogenesis in vitro. We showed that the latter is likely mediated by pro-B cells expressing the MCS-F receptor (CD115) and capable of transdifferentiation to osteoclasts (Abstract # 1007, EHA 2017). Here we address the role of B cell-specific EPO-R in EPO-induced bone loss (i.e. at supra-physiological EPO levels). Moreover, we demonstrate, for the first time, the occurrence of B cell-derived osteoclastogenesis in vivo, a finding of critical importance in the field of osteohematology. Methods: In order to trace the B cell lineage from its earliest precursors, we used the MB1-Cre mouse line combined with either the R26R-EYFP or the EPO-Rfl/fl mice for lineage tracing and B cell-specific EPO-R knockdown, respectively. Sequential fluorescence and light microscopy were used for the demonstration of B cell-derived osteoclastogenesis in vivo. Human recombinant EPO was administered in vivo at a dose of 180IU thrice weekly for two weeks. Immunophenotyping of BM B cell populations was assessed by multi-color flow cytometry. Results: Using female MB1-Cre; EPO-Rfl/fl (cKD) mice, we found that B cell-specific EPO-R knockdown attenuated the profound EPO-induced trabecular bone loss in the proximal part of the femoral distal metaphysis (proximal BV/TV 0.034±0.012% vs 0.007±0.003% in the cKD vs control mice, p<0.05, Figure 1). Remarkably, this effect was observed despite the fact that cKD mice attained higher hemoglobin levels following EPO treatment (21.1±0.1 mg/dL vs 20.4±0.2 mg/dL in the cKD vs control mice, p<0.05). An EPO-induced increase in CD115+ Pro-B cells was observed in EPO-treated control mice but was absent in the cKD mice. The latter finding correlates with the observed bone loss and indicates that the increased number of MCSF-R-expressing pro-B cells is dependent on B cell EPO-R. Supporting the osteoclastic potential of this specific B cell subpopulation is the fact that most of the CD115+ Pro-B cells also express β3 integrin (CD61) which is essential for osteoclast differentiation and function. Using the MB1-Cre;R26R-EYFP murine model for B cell lineage tracing, we could demonstrate that some of the TRAP+/ β3 integrin+ bone lining cells were also positive for EYFP (Figure 2). This demonstrates the B cell origin of some of the osteoclasts in vivo. Conclusions: Our work highlights B cells as an important extra-erythropoietic target of EPO-EPO-R signaling that regulates bone homeostasis and might also indirectly affect EPO-stimulated erythropoietic response. The relevance and the mechanisms of the latter phenomenon merits further investigation. Importantly, we present here, for the first time, histological evidence for B cell-derived osteoclastogenesis in vivo, thus opening novel research avenues. DN and YG Equal contribution Funded by the German Israel Foundation, Grant # 01021017 to YG, DN, MR and BW and by the Israel Science Foundation (ISF) Grant No. 343/17 to DN. Disclosures Mittelman: Novartis: Honoraria, Research Funding, Speakers Bureau.

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