The Mechanisms of Bone Loss due to Estrogen Deficiency: Possible Role of Increased B-Lymphopoiesis in Bone Resorption

Author(s):  
C. Miyaura
2011 ◽  
Vol 115 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Suguru Harada ◽  
Tsukasa Tominari ◽  
Chiho Matsumoto ◽  
Michiko Hirata ◽  
Morichika Takita ◽  
...  

Endocrinology ◽  
2016 ◽  
Vol 157 (7) ◽  
pp. 2621-2635 ◽  
Author(s):  
Seong Hee Ahn ◽  
Sook-Young Park ◽  
Ji-Eun Baek ◽  
Su-Youn Lee ◽  
Wook-Young Baek ◽  
...  

Free fatty acid receptor 4 (FFA4) has been reported to be a receptor for n-3 fatty acids (FAs). Although n-3 FAs are beneficial for bone health, a role of FFA4 in bone metabolism has been rarely investigated. We noted that FFA4 was more abundantly expressed in both mature osteoclasts and osteoblasts than their respective precursors and that it was activated by docosahexaenoic acid. FFA4 knockout (Ffar4−/−) and wild-type mice exhibited similar bone masses when fed a normal diet. Because fat-1 transgenic (fat-1Tg+) mice endogenously converting n-6 to n-3 FAs contain high n-3 FA levels, we crossed Ffar4−/− and fat-1Tg+ mice over two generations to generate four genotypes of mice littermates: Ffar4+/+;fat-1Tg−, Ffar4+/+;fat-1Tg+, Ffar4−/−;fat-1Tg−, and Ffar4−/−;fat-1Tg+. Female and male littermates were included in ovariectomy- and high-fat diet-induced bone loss models, respectively. Female fat-1Tg+ mice decreased bone loss after ovariectomy both by promoting osteoblastic bone formation and inhibiting osteoclastic bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In a high-fat diet-fed model, male fat-1Tg+ mice had higher bone mass resulting from stimulated bone formation and reduced bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In vitro studies supported the role of FFA4 as n-3 FA receptor in bone metabolism. In conclusion, FFA4 is a dual-acting factor that increases osteoblastic bone formation and decreases osteoclastic bone resorption, suggesting that it may be an ideal target for modulating metabolic bone diseases.


2018 ◽  
Vol 9 ◽  
Author(s):  
Kun Chen ◽  
Zheng-tao Lv ◽  
Peng Cheng ◽  
Wen-tao Zhu ◽  
Shuang Liang ◽  
...  

2020 ◽  
Vol 21 (8) ◽  
pp. 2745
Author(s):  
Yukihiro Kohara ◽  
Ryuma Haraguchi ◽  
Riko Kitazawa ◽  
Yuuki Imai ◽  
Sohei Kitazawa

The functional role of the Hedgehog (Hh)-signaling pathway has been widely investigated in bone physiology/development. Previous studies have, however, focused primarily on Hh functions in bone formation, while its roles in bone resorption have not been fully elucidated. Here, we found that cyclopamine (smoothened (Smo) inhibitor), GANT-58 (GLI1 inhibitor), or GANT-61 (GLI1/2 inhibitor) significantly inhibited RANKL-induced osteoclast differentiation of bone marrow-derived macrophages. Although the inhibitory effects were exerted by cyclopamine or GANT-61 treatment during 0–48 h (early stage of osteoclast differentiation) or 48–96 h (late stage of osteoclast differentiation) after RANKL stimulation, GANT-58 suppressed osteoclast formation only during the early stage. These results suggest that the Smo-GLI1/2 axis mediates the whole process of osteoclastogenesis and that GLI1 activation is requisite only during early cellular events of osteoclastogenesis. Additionally, macrophage/osteoclast-specific deletion of Smo in mice was found to attenuate the aging phenotype characterized by trabecular low bone mass, suggesting that blockage of the Hh-signaling pathway in the osteoclast lineage plays a protective role against age-related bone loss. Our findings reveal a specific role of the Hh-signaling pathway in bone resorption and highlight that its inhibitors show potential as therapeutic agents that block osteoclast formation in the treatment of senile osteoporosis.


2014 ◽  
Vol 74 (6) ◽  
pp. 1284-1292 ◽  
Author(s):  
Iannis E Adamopoulos ◽  
Erika Suzuki ◽  
Cheng-Chi Chao ◽  
Dan Gorman ◽  
Sarvesh Adda ◽  
...  

BackgroundPsoriatic arthritis (PsA) is a chronic inflammatory disease characterised by clinical features that include bone loss and epidermal hyperplasia. Aberrant cytokine expression has been linked to joint and skin pathology; however, it is unclear which cytokines are critical for disease initiation. Interleukin 17A (IL-17A) participates in many pathological immune responses; however, its role in PsA has not been fully elucidated.ObjectiveTo determine the role of IL-17A in epidermal hyperplasia and bone destruction associated with psoriatic arthritis.DesignAn in vivo gene transfer approach was used to investigate the role of IL-17A in animal models of inflammatory (collagen-induced arthritis) and non-inflammatory (receptor activator of NF-κB ligand (RANKL)-gene transfer) bone loss.ResultsIL-17A gene transfer induced the expansion of IL-17RA+CD11b+Gr1low osteoclast precursors and a concomitant elevation of biomarkers indicative of bone resorption. This occurred at a time preceding noticeable joint inflammation, suggesting that IL-17A is critical for the induction of pathological bone resorption through direct activation of osteoclast precursors. Moreover, IL-17A induced a second myeloid population CD11b+Gr1high neutrophil-like cells, which was associated with cutaneous pathology including epidermal hyperplasia, parakeratosis and Munro's microabscesses formation.ConclusionsCollectively, these data support that IL-17A can play a key role in the pathogenesis of inflammation-associated arthritis and/or skin disease, as observed in PsA.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Piero Ruscitti ◽  
Paola Cipriani ◽  
Francesco Carubbi ◽  
Vasiliki Liakouli ◽  
Francesca Zazzeroni ◽  
...  

Several inflammatory diseases have been associated with increased bone resorption and fracture rates and different studies supported the relation between inflammatory cytokines and osteoclast activity. The main factor required for osteoclast activation is the stimulation by receptor activator of nuclear factor kappa-B ligand (RANKL) expressed on osteoblasts. In this context, interleukin- (IL-) 1β, one of the most powerful proinflammatory cytokines, is a strong stimulator of in vitro and in vivo bone resorption via upregulation of RANKL that stimulates the osteoclastogenesis. The resulting effects lead to an imbalance in bone metabolism favouring bone resorption and osteoporosis. In this paper, we review the available literature on the role of IL-1βin the pathogenesis of bone loss. Furthermore, we analysed the role of IL-1βin bone resorption during rheumatic diseases and, when available, we reported the efficacy of anti-IL-1βtherapy in this field.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 15-16
Author(s):  
Jing Fu ◽  
Shirong Li ◽  
Huihui Ma ◽  
Jun Yang ◽  
Gabriel M. Pagnotti ◽  
...  

Introduction Multiple myeloma (MM) bone disease remains one of the most devastating complications of this incurable cancer, causing bone fractures, pain, mobility issues and neurological deficits. MM cells produce osteoclast-activating factors that induce osteoclast activation, thereby leading to excessive bone resorption and lytic bone lesions1. Our previous work demonstrated that matrix metalloproteinase 13 (MMP-13) is a critical osteoclastogenic factor that is highly secreted by MM cells. MMP-13 induces osteoclast fusion and bone-resorption via a mechanism independent of its proteolytic activity2. We recently reported that MMP-13 binds to checkpoint inhibitor programmed death-1 homolog (PD-1H/VISTA), a surface receptor that is expressed in osteoclasts at high levels3. Binding of MMP-13 to PD-1H/VISTA induces osteoclast fusion and bone resorption activity whereas knockdown or knockout of PD-1H/VISTA largely block MMP-13 mediated effects on osteoclasts3. However, the function of PD-1H inMM bone disease in vitro or in vivo has not been previously defined. Methods and Results To confirm the role of PD-1H in MMP-13 induced bone disease in MM, we first conducted MM-osteoclast trans-well co-culture assay using murine MM cell line, 5TGM1 cells, and bone marrow mononuclear cells from Pd-1h-/- or wild type (WT) mice. 5TGM1 control cells or MMP-13 knockdown 5TGM1 cells were seeded in the upper wells of the transwell plates; while WT or Pd-1h-/- bone marrow mononuclear cells were seeded in the lower wells and cultured for osteoclast differentiation assessed by TRAP staining. Results show that 5TGM1 induced differentiation of WT osteoclasts with significantly increased osteoclast size and nuclei number/osteoclast. Consistent with our previous results2, MMP-13 knockdown blocked the 5TGM1 MM cells-induced activation of WT osteoclasts. In contrast, neither 5TGM1 MM cells nor MMP-13 knockdown cells had significant effects on Pd-1h-/- osteoclasts. Hence, knockout of Pd-1h abrogated MMP-13 mediated MM induction of osteoclasts, indicating that MMP-13/PD-1H interactions are critically involved in MM-induced osteoclast activation. The in vivo role of PD-1H in MM bone disease was investigated using the intratibial 5TGM1 Rag2-/- MM bone disease mice model2. For this purpose, Pd-1h-/-Rag2-/- mice were generated by crossbreeding C57BL/6 Pd-1h-/- with C57BL/6 Rag2-/- mice. 3x105 firefly luciferase expressing 5TGM1 cells (5TGM1-luc) were intratibially injected into age and sex-paired Rag2-/- or Pd-1h-/-Rag2-/- mice (N=5). Tumor progression was monitored by weekly bioluminescence imaging (BLI). 3 weeks after tumor inoculation, tibiae were harvested for quantitative micro-CT, followed by histological analysis. Histological staining showed that intratibial injection of 5TGM1-luc MM cells induced extensive lytic lesions and trabecular bone loss in Rag2-/- mice. In contrast, in Pd-1h-/-Rag2-/- mice,the bone structure was maintained with markedly less bone loss. Morphological analyses of trabecular bone across proximal tibiae further indicated that in Rag2-/- mice, 5TGM1 induced significant changes in bone microarchitecture, with decreased bone volume fraction (bone volume/tissue volume), connective density, trabecular bone numbers, and trabecular bone thickness, as well as increased trabecular bone spacing (Table 1). In contrast, in Pd-1h-/-Rag2-/- mice, 5TGM1 failed to induce significant loss of trabecular bone, confirming the critical role of PD-1H in MM induced bone disease in vivo. Conclusions Taken together, our study, for the first time, reveal that checkpoint inhibitor PD-1H/VISTA is the critical receptor for MMP-13 in osteoclasts, thereby mediating MMP-13-induced osteoclast fusion, activation and bone resorption. MM-induced trabecular bone loss was significantly lower in Pd-1h-/-mice, demonstrating that PD-1H/VISTA plays a critical role in MMP-13-induced MM bone disease. Given the checkpoint role of PD-1H/VISTA in cancer immunosuppression, we further posit that targeting the interaction of MMP-13 and PD-1H may represent a novel therapeutic strategy to treat MM bone disease and modulate the MM immune environment. References 1. Marino S, Petrusca DN, Roodman GD. Br J Pharmacol. 2019;10.1111/bph.14889. 2. Fu J, Li S, Feng R, et al. J Clin Invest. 2016;126(5):1759-1772. 3. Fu J, Li S, Yang C, et al. Blood. 2019; 134 (Supplement_1): 3072. Disclosures Lentzsch: Caelum Biosciences: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Celularity: Consultancy, Other; Magenta: Current equity holder in private company; Karyopharm: Research Funding; Mesoblast: Divested equity in a private or publicly-traded company in the past 24 months.


1997 ◽  
Vol 52 (7) ◽  
pp. 429-431 ◽  
Author(s):  
W. Roland McKane ◽  
Sundeep Khosla ◽  
Juha Ristela ◽  
Simon P. Robins ◽  
Joan M. Muhs ◽  
...  

2003 ◽  
Vol 197 (10) ◽  
pp. 1303-1310 ◽  
Author(s):  
Chisato Miyaura ◽  
Masaki Inada ◽  
Chiho Matsumoto ◽  
Tomoyasu Ohshiba ◽  
Naonori Uozumi ◽  
...  

Prostaglandin E (PGE)2 produced by osteoblasts acts as a potent stimulator of bone resorption. Inflammatory bone loss is accompanied by osteoclast formation induced by bone-resorbing cytokines, but the mechanism of PGE2 production and bone resorption in vivo is not fully understood. Using cytosolic phospholipase A2α (cPLA2α)-null mice, we examined the role of cPLA2α in PGE2 synthesis and bone resorption. In bone marrow cultures, interleukin (IL)-1 markedly stimulated PGE2 production and osteoclast formation in wild-type mice, but not in cPLA2α-null mice. Osteoblastic bone marrow stromal cells induced the expression of cyclooxygenase (COX)-2 and membrane-bound PGE2 synthase (mPGES) in response to IL-1 and lipopolysaccharide (LPS) to produce PGE2. Osteoblastic stromal cells collected from cPLA2α-null mice also induced the expression of COX-2 and mPGES by IL-1 and LPS, but could not produce PGE2 due to the lack of arachidonic acid release. LPS administration to wild-type mice reduced femoral bone mineral density by increased bone resorption. In cPLA2α-null mice, however, LPS-induced bone loss could not be observed at all. Here, we show that cPLA2α plays a key role in PGE production by osteoblasts and in osteoclastic bone resorption, and suggest a new approach to inflammatory bone disease by inhibiting cPLA2α.


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