scholarly journals Leptin directly regulates bone cell function in vitro and reduces bone fragility in vivo

2002 ◽  
Vol 175 (2) ◽  
pp. 405-415 ◽  
Author(s):  
J Cornish ◽  
KE Callon ◽  
U Bava ◽  
C Lin ◽  
D Naot ◽  
...  
Keyword(s):  
Bone Mass ◽  
Leptin Receptor ◽  
Cell Function ◽  
Plate Thickness ◽  
Bone Fragility ◽  
Bone Cell ◽  
Mouse Bone Marrow ◽  
High Bone Mass

Fat mass is an important determinant of bone density, but the mechanism of this relationship is uncertain. Leptin, as a circulating peptide of adipocyte origin, is a potential contributor to this relationship. Recently it was shown that intracerebroventricular administration of leptin is associated with bone loss, suggesting that obesity should be associated with low bone mass, the opposite of what is actually found. Since leptin originates in the periphery, an examination of its direct effects on bone is necessary to address this major discrepancy. Leptin (>10(-11) m) increased proliferation of isolated fetal rat osteoblasts comparably with IGF-I, and these cells expressed the signalling form of the leptin receptor. In mouse bone marrow cultures, leptin (>or=10(-11) m) inhibited osteoclastogenesis, but it had no effect on bone resorption in two assays of mature osteoclasts. Systemic administration of leptin to adult male mice (20 injections of 43 micro g/day over 4 weeks) reduced bone fragility (increased work to fracture by 27% and displacement to fracture by 21%, P<0.001). Changes in tibial histomorphometry were not statistically significant apart from an increase in growth plate thickness in animals receiving leptin. Leptin stimulated proliferation of isolated chondrocytes, and these cells also expressed the signalling form of the leptin receptor. It is concluded that the direct bone effects of leptin tend to reduce bone fragility and could contribute to the high bone mass and low fracture rates of obesity. When administered systemically, the direct actions of leptin outweigh its centrally mediated effects on bone, the latter possibly being mediated by leptin's regulation of insulin sensitivity.

Clopidogrel (plavix), a P2Y12 receptor antagonist, inhibits bone cell function in vitro and decreases trabecular bone in vivo

Bone ◽  
2012 ◽  
Vol 50 ◽  
pp. S45
Author(s):  
S. Syberg ◽  
A. Brandao-Burch ◽  
J.J. Patel ◽  
M.O. Hajjawi ◽  
T.R. Arnett ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Trabecular Bone ◽  
Cell Function ◽  
Bone Cell ◽  
P2y12 Receptor ◽  
P2y12 Receptor Antagonist

scholarly journals Clopidogrel (Plavix), a P2Y12receptor antagonist, inhibits bone cell function in vitro and decreases trabecular bone in vivo

2012 ◽  
Vol 27 (11) ◽  
pp. 2373-2386 ◽  
Author(s):  
Susanne Syberg ◽  
Andrea Brandao-Burch ◽  
Jessal J Patel ◽  
Mark Hajjawi ◽  
Timothy R Arnett ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Cell Function ◽  
Bone Cell

scholarly journals The P2Y6 Receptor Stimulates Bone Resorption by Osteoclasts

Endocrinology ◽  
2011 ◽  
Vol 152 (10) ◽  
pp. 3706-3716 ◽  
Author(s):  
Isabel R. Orriss ◽  
Ning Wang ◽  
Geoffrey Burnstock ◽  
Timothy R. Arnett ◽  
Alison Gartland ◽  
...  
Keyword(s):  
Cell Function ◽  
Bone Cell ◽  
Extracellular Nucleotides ◽  
P2y6 Receptor ◽  
Tomographic Analysis ◽  
G Protein Coupled ◽  
Resorptive Activity

Accumulating evidence indicates that extracellular nucleotides, signaling through P2 receptors, play a significant role in bone remodeling. Osteoclasts (the bone-resorbing cell) and osteoblasts (the bone-forming cell) display expression of the G protein-coupled P2Y6 receptor, but the role of this receptor in modulating cell function is unclear. Here, we demonstrate that extracellular UDP, acting via P2Y6 receptors, stimulates the formation of osteoclasts from precursor cells, while also enhancing the resorptive activity of mature osteoclasts. Furthermore, osteoclasts derived from P2Y6 receptor-deficient (P2Y6R−/−) animals displayed defective function in vitro. Using dual energy x-ray absorptiometry scanning and microcomputed tomographic analysis we showed that P2Y6R−/− mice have increased bone mineral content, cortical bone volume, and cortical thickness in the long bones and spine, whereas trabecular bone parameters were unaffected. Histomorphometric analysis showed the perimeter of the bone occupied by osteoclasts on the endocortical and trabecular surfaces was decreased in P2Y6R−/− mice. Taken together these results show the P2Y6 receptor may play an important role in the regulation of bone cell function in vivo.

scholarly journals Preptin, another peptide product of the pancreatic β-cell, is osteogenic in vitro and in vivo

2007 ◽  
Vol 292 (1) ◽  
pp. E117-E122 ◽  
Author(s):  
J. Cornish ◽  
K. E. Callon ◽  
U. Bava ◽  
M. Watson ◽  
X. Xu ◽  
...  
Keyword(s):  
Bone Mass ◽  
Map Kinases ◽  
Cell Number ◽  
Dependent Manner ◽  
Pancreatic Β Cell ◽  
Hepatitis C Infection ◽  
Β Cell ◽  
High Bone Mass

Several hormones that regulate nutritional status also impact on bone metabolism. Preptin is a recently isolated 34-amino acid peptide hormone that is cosecreted with insulin and amylin from the pancreatic β-cells. Preptin corresponds to Asp69-Leu102 of pro-IGF-II. Increased circulating levels of a pro-IGF-II peptide complexed with IGF-binding protein-2 have been implicated in the high bone mass phenotype observed in patients with chronic hepatitis C infection. We have assessed preptin's activities on bone. Preptin dose-dependently stimulated the proliferation (cell number and DNA synthesis) of primary fetal rat osteoblasts and osteoblast-like cell lines at periphysiological concentrations (>10−11 M). In addition, thymidine incorporation was stimulated in murine neonatal calvarial organ culture, likely reflecting the proliferation of cells from the osteoblast lineage. Preptin did not affect bone resorption in this model. Preptin induced phosphorylation of p42/p44 MAP kinases in osteoblastic cells in a dose-dependent manner (10−8-10−10 M), and its proliferative effects on primary osteoblasts were blocked by MAP kinase kinase inhibitors. Preptin also reduced osteoblast apoptosis induced by serum deprivation, reducing the number of apoptotic cells by >20%. In vivo administration of preptin increased bone area and mineralizing surface in adult mice. These data demonstrate that preptin, which is cosecreted from the pancreatic β-cell with amylin and insulin, is anabolic to bone and may contribute to the preservation of bone mass observed in hyperinsulinemic states such as obesity.

scholarly journals Review on material parameters to enhance bone cell function in vitro and in vivo

2020 ◽  
Vol 48 (5) ◽  
pp. 2039-2050
Author(s):  
Eric Madsen ◽  
Merjem Mededovic ◽  
David H. Kohn
Keyword(s):  
Cell Function ◽  
Bone Cells ◽  
Bone Cell ◽  
Bone Augmentation ◽  
Material Parameters ◽  
Specific Material ◽  
Resorbable Implants ◽  
Resorbable Materials

Bone plays critical roles in support, protection, movement, and metabolism. Although bone has an innate capacity for regeneration, this capacity is limited, and many bone injuries and diseases require intervention. Biomaterials are a critical component of many treatments to restore bone function and include non-resorbable implants to augment bone and resorbable materials to guide regeneration. Biomaterials can vary considerably in their biocompatibility and bioactivity, which are functions of specific material parameters. The success of biomaterials in bone augmentation and regeneration is based on their effects on the function of bone cells. Such functions include adhesion, migration, inflammation, proliferation, communication, differentiation, resorption, and vascularization. This review will focus on how different material parameters can enhance bone cell function both in vitro and in vivo.

scholarly journals Selective deletion of the receptor for CSF1, c-fms, in osteoclasts results in a high bone mass phenotype, smaller osteoclasts in vivo and an impaired response to an anabolic PTH regimen

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247199
Author(s):  
Meiling Zhu ◽  
Ben-hua Sun ◽  
Erin Nevius ◽  
Jared Kaplan ◽  
João Pereira ◽  
...  
Keyword(s):  
Bone Mass ◽  
Trabecular Bone ◽  
Cathepsin K ◽  
Normal Weight ◽  
High Bone Mass ◽  
Knock Out ◽  
High Bone ◽  
Knock Out Mice

The receptor for Colony Stimulating Factor 1 (CSF1), c-fms, is highly expressed on mature osteoclasts suggesting a role for this cytokine in regulating the function of these cells. Consistent with this idea, in vitro studies have documented a variety of effects of CSF1 in mature osteoclasts. To better define the role of CSF1 in these cells, we conditionally deleted c-fms in osteoclasts (c-fms-OC-/-) by crossing c-fmsflox/flox mice with mice expressing Cre under the control of the cathepsin K promoter. The c-fms-OC-/- mice were of normal weight and had normal tooth eruption. However, when quantified by DXA, bone mass was significantly higher in the spine and femur of female knock out mice and in the femurs of male knock out mice. MicroCT analyses of femurs showed that female c-fms-OC-/- mice had significantly increased trabecular bone mass with a similar trend in males and both sexes demonstrated significantly increased trabecular number and reduced trabecular spacing. Histomorphometric analysis of the femoral trabecular bone compartment demonstrated a trend towards increased numbers of osteoclasts, +26% in Noc/BPm and +22% in OcS/BS in the k/o animals but this change was not significant. However, when the cellular volume of osteoclasts was quantified, the c-fms-OC-/- cells were found to be significantly smaller than controls. Mature osteoclasts show a marked spreading response when exposed to CSF1 in a non-gradient fashion. However, osteoclasts freshly isolated from c-fms-OC-/- mice had a near complete abrogation of this response. C-fms-OC-/- mice treated with (1–34)hPTH 80 ng/kg/d in single daily subcutaneous doses for 29 days showed an attenuated anabolic response in trabecular bone compared to wild-type animals. Taken together, these data indicate an important non-redundant role for c-fms in regulating mature osteoclast function in vivo.

From Mouse to Man: Redefining the Role of Insulin-Like Growth Factor-I in the Acquisition of Bone Mass

2003 ◽  
Vol 228 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Shoshana Yakar ◽  
Clifford J. Rosen
Keyword(s):  
Growth Factor ◽  
Cell Function ◽  
Bone Cells ◽  
Bone Cell ◽  
Insulin Like Growth Factor ◽  
In Vivo Models ◽  
Igf I

The insulin-like growth factor system (IGF) has been linked to the process of bone acquisition through epidemiologic analyses of large cohorts and in vitro studies of bone cells. But the exact relationship between expression of IGF-I in bone and skeletal homeostasis or pathologic conditions, such as osteoporosis, remains poorly defined. Recent advances in genomic engineering have resulted in the development of better in vivo models to test the role of IGF-I during development and maintenance of the adult skeleton. It is now established that skeletal expression of IGF-I is critical for differentiative bone cell function. It may also be essential for the full anabolic effects of parathyroid hormone on trabecular bone and for some component of biomineralization. Evidence from conditional mutagenesis studies suggests that serum IGF-I may represent more than a storage depot or permissive factor during the final phase of skeletal acquisition. This work re-examines the original tenets of the “somatomedin hypothesis” in light of these newer mouse models and their remarkable skeletal phenotypes. The implications are far reaching and suggest that newer approaches for manipulating the IGF regulatory system may one day be useful as therapeutic adjuncts for the treatment of osteoporosis.

scholarly journals Amylin inhibits bone resorption while the calcitonin receptor controls bone formation in vivo

2004 ◽  
Vol 164 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Romain Dacquin ◽  
Rachel A. Davey ◽  
Catherine Laplace ◽  
Régis Levasseur ◽  
Howard A. Morris ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Bone Mass ◽  
Dependent Manner ◽  
Calcitonin Receptor ◽  
Low Bone Mass ◽  
High Bone Mass ◽  
High Bone

Amylin is a member of the calcitonin family of hormones cosecreted with insulin by pancreatic β cells. Cell culture assays suggest that amylin could affect bone formation and bone resorption, this latter function after its binding to the calcitonin receptor (CALCR). Here we show that Amylin inactivation leads to a low bone mass due to an increase in bone resorption, whereas bone formation is unaffected. In vitro, amylin inhibits fusion of mononucleated osteoclast precursors into multinucleated osteoclasts in an ERK1/2-dependent manner. Although Amylin +/− mice like Amylin-deficient mice display a low bone mass phenotype and increased bone resorption, Calcr +/− mice display a high bone mass due to an increase in bone formation. Moreover, compound heterozygote mice for Calcr and Amylin inactivation displayed bone abnormalities observed in both Calcr +/− and Amylin +/− mice, thereby ruling out that amylin uses CALCR to inhibit osteoclastogenesis in vivo. Thus, amylin is a physiological regulator of bone resorption that acts through an unidentified receptor.

Megakaryocyte-driven changes in bone health: lessons from mouse models of myelofibrosis and related disorders

2021 ◽  
Author(s):  
Mariya Stavnichuk ◽  
Svetlana V. Komarova
Keyword(s):  
Bone Marrow ◽  
Mouse Models ◽  
Cell Function ◽  
Bone Cells ◽  
Bone Marrow Cells ◽  
Bone Cell ◽  
Bone Architecture ◽  
Bone Homeostasis

Over the years, numerous studies demonstrated reciprocal communications between processes of bone marrow hematopoiesis and bone remodeling. Megakaryocytes, rare bone marrow cells responsible for platelet production, were demonstrated to be involved in bone homeostasis. Myelofibrosis, characterized by an increase in pleomorphic megakaryocytes in the bone marrow, commonly leads to the development of osteosclerosis. In vivo, an increase in megakaryocyte number was shown to result in osteosclerosis in GATA-1low, NF-E2-/-, TPOhigh, Mpllf/f;PF4cre, Lnk-/-, Mpig6b-/-, Mpig6bfl/fl;Gp1ba-Cr+/KI, Pt-vWD mouse models. In vitro, megakaryocytes stimulate osteoblast proliferation and have variable effects on osteoclast proliferation and activity through soluble factors and direct cell-cell communications. Intriguingly, new studies revealed that the ability of megakaryocytes to communicate with bone cells is affected by the age and sex of animals. This mini-review summarises changes seen in bone architecture and bone cell function in mouse models with an elevated number of megakaryocytes and the effects megakaryocytes have on osteoblasts and osteoclasts in vitro, and discusses potential molecular players that can mediate these effects.

scholarly journals In Vitro and in Vivo Effects of Adiponectin on Bone

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3603-3610 ◽  
Author(s):  
Garry A. Williams ◽  
Yu Wang ◽  
Karen E. Callon ◽  
Maureen Watson ◽  
Jian-ming Lin ◽  
...  
Keyword(s):  
Bone Mass ◽  
Primary Cultures ◽  
Biomechanical Testing ◽  
Osteoporotic Fractures ◽  
Bone Fragility ◽  
Raw 264.7 Cells ◽  
In Vivo Effects ◽  
Trabecular Number

Fat mass impacts on both bone turnover and bone density and is a critical risk factor for osteoporotic fractures. Adipocyte-derived hormones may contribute to this relationship, and adiponectin is a principal circulating adipokine. However, its effects on bone remain unclear. We have, therefore, investigated the direct effects of adiponectin on primary cultures of osteoblastic and osteoclastic cells in vitro and determined its integrated effects in vivo by characterizing the bone phenotype of adiponectin-deficient mice. Adiponectin was dose-dependently mitogenic to primary rat and human osteoblasts (∼50% increase at 10 μg/ml) and markedly inhibited osteoclastogenesis at concentrations of 1 μg/ml or greater. It had no effect on osteoclastogenesis in RAW-264.7 cells or on bone resorption in isolated mature osteoclasts. In adiponectin knockout (AdKO) male C57BL/6J mice, trabecular bone volume and trabecular number (assessed by microcomputed tomography) were increased at 14 wk of age by 30% (P = 0.02) and 38% (P = 0.0009), respectively. Similar, nonsignificant trends were observed at 8 and 22 wk of age. Biomechanical testing showed lower bone fragility and reduced cortical hardness at 14 wk. We conclude that adiponectin stimulates osteoblast growth but inhibits osteoclastogenesis, probably via an effect on stromal cells. However, the AdKO mouse has increased bone mass, suggesting that adiponectin also has indirect effects on bone, possibly through modulating growth factor action or insulin sensitivity. Because adiponectin does influence bone mass in vivo, it is likely to be a contributor to the fat-bone relationship.

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