Psoralen and Bakuchiol Ameliorate M-CSF Plus RANKL-Induced Osteoclast Differentiation and Bone Resorption Via Inhibition of AKT and AP-1 Pathways in Vitro

Background/Aims: Psoralen and bakuchiol are the main active compounds found in the traditional Chinese medicine Psoralea corylifolia L., and have been used to treat osteoporosis. This study aims to investigate the anti-osteoporosis effects of these two compounds using osteoclasts precursor differentiation and bone absorption assays in vitro. Methods: Primary mouse osteoclasts precursor cells were induced by M-CSF (macrophage colony stimulating factor) plus RANKL (receptor activator of nuclear factor kappa-B ligand) in vitro. TRACP (tartrate-resistant acid phosphatase) enzyme activity and toluidine blue staining were used to observe the effects of psoralen and bakuchiol on osteoclast differentiation and bone resorption, respectively. Gelatin zymography was used to assess MMP (matrix metalloproteinase) activity, and ELISA was performed to measure cathepsin K activity. Western blotting analysis for expression of phosphorylated AKT, ERK, NF-kB, and c-jun; and immunofluorescence analysis for c-jun and p65 nuclear translocation in induced osteoclasts were then used to determine the mechanism of anti-bone resorption of psoralen and bakuchiol. Results: Mature osteoclasts were induced by M-CSF plus RANKL from primary bone marrow macrophages in vitro. Both psoralen and bakuchiol significantly inhibited TRACP enzyme activity and slightly decreased the number of TRACP+ multinuclear osteoclasts induced by M-CSF plus RANKL. Bakuchiol significantly decreased bone lacunae area and attenuated MMP-2 activity induced by M-CSF plus RANKL in osteoclasts. Both psoralen and bakuchiol significantly decreased the expression and nuclear translocation of phosphorylated c-jun stimulated by M-CSF plus RANKL, but no significant effect on p65 translocation was observed in osteoclasts. Additionally, bakuchiol significantly attenuated the increased of M-CSF plus RANKL-induced phosphorylation of AKT in osteoclasts. Conclusions: Psoralen and bakuchiol ameliorated M-CSF plus RANKL-induced osteoclast differentiation and bone resorption via inhibition of AKT and AP-1 pathways activation in vitro.

Download Full-text

Inhibition of RANKL-Induced Osteoclastogenesis by Novel Mutant RANKL

International Journal of Molecular Sciences ◽

10.3390/ijms22010434 ◽

2021 ◽

Vol 22 (1) ◽

pp. 434

Author(s):

Yuria Jang ◽

Hong Moon Sohn ◽

Young Jong Ko ◽

Hoon Hyun ◽

Wonbong Lim

Keyword(s):

Nuclear Translocation ◽

Critical Role ◽

Osteoclast Differentiation ◽

Point Mutations ◽

Tartrate Resistant Acid Phosphatase ◽

Mice Model ◽

Gsk 3Β ◽

Rank Signaling

Background: Recently, it was reported that leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4, also called GPR48) is another receptor for RANKL and was shown to compete with RANK to bind RANKL and suppress canonical RANK signaling during osteoclast differentiation. The critical role of the protein triad RANK–RANKL in osteoclastogenesis has made their binding an important target for the development of drugs against osteoporosis. In this study, point-mutations were introduced in the RANKL protein based on the crystal structure of the RANKL complex and its counterpart receptor RANK, and we investigated whether LGR4 signaling in the absence of the RANK signal could lead to the inhibition of osteoclastogenesis.; Methods: The effects of point-mutated RANKL (mRANKL-MT) on osteoclastogenesis were assessed by tartrate-resistant acid phosphatase (TRAP), resorption pit formation, quantitative real-time polymerase chain reaction (qPCR), western blot, NFATc1 nuclear translocation, micro-CT and histomorphological assay in wild type RANKL (mRANKL-WT)-induced in vitro and in vivo experimental mice model. Results: As a proof of concept, treatment with the mutant RANKL led to the stimulation of GSK-3β phosphorylation, as well as the inhibition of NFATc1 translocation, mRNA expression of TRAP and OSCAR, TRAP activity, and bone resorption, in RANKL-induced mouse models; and Conclusions: The results of our study demonstrate that the mutant RANKL can be used as a therapeutic agent for osteoporosis by inhibiting RANKL-induced osteoclastogenesis via comparative inhibition of RANKL. Moreover, the mutant RANKL was found to lack the toxic side effects of most osteoporosis treatments.

Download Full-text

Edgeworthia papyrifera Regulates Osteoblast and Osteoclast Differentiation In Vitro and Exhibits Anti-osteoporosis Activity in Animal Models of Osteoporosis

Planta Medica ◽

10.1055/a-0942-1960 ◽

2019 ◽

Vol 85 (09/10) ◽

pp. 766-773 ◽

Cited By ~ 1

Author(s):

Pansoo Kim ◽

Yeon-Ju Nam ◽

Woo Jung Kim ◽

Jin Kyu Kim ◽

Gyeongbeen Lee ◽

...

Keyword(s):

Bone Resorption ◽

Animal Models ◽

Osteoclast Differentiation ◽

Raw 264.7 Cells ◽

Tartrate Resistant Acid Phosphatase ◽

Raw 264.7 ◽

Treatment Of Osteoporosis ◽

Increased Risk ◽

Interesting Candidate

AbstractOsteoporosis is a clinical condition characterized by low bone strength that leads to an increased risk of fracture. Strategies for the treatment of osteoporosis involve inhibition of bone resorption by osteoclasts and an increase of bone formation by osteoblasts. Here, we identified the extract derived from the stem part of Edgeworthia papyrifera that enhanced differentiation of MC3T3-E1 cells to osteoblast-like cells and inhibited osteoclast differentiation of RAW 264.7 cells in vitro. In support of our observation, rutin and daphnoretin, which were previously reported to inhibit osteoclast differentiation, were identified in E. papyrifera extract. In an animal model of osteoporosis, the ovariectomy-induced increases in bone resorption biomarkers such as pyridinoline and tartrate-resistant acid phosphatase were significantly reduced by E. papyrifera extract administration at 25.6 and 48.1%, respectively. Furthermore, the ovariectomy-induced bone loss in animal models of osteoporosis was significantly prevented by the administration of E. papyrifera in our study. Taking these observations into account, we suggest that E. papyrifera is an interesting candidate for further exploration as an anti-osteoporotic agent.

Download Full-text

Effects of Isoliquiritigenin on Bone Metabolism and Uterus in Ovariectomized Rats

Current Developments in Nutrition ◽

10.1093/cdn/nzaa045_102 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 469-469

Author(s):

Lara Sattgast ◽

Carmen Wong ◽

Daniel Doerge ◽

William Helferich ◽

Urszula Iwaniec ◽

...

Keyword(s):

Gene Expression ◽

Bone Resorption ◽

Epithelial Cell ◽

Osteoclast Differentiation ◽

Ovariectomized Rats ◽

Tartrate Resistant Acid Phosphatase ◽

Uterine Weight ◽

Uterine Epithelial Cell ◽

Ovx Rats

Abstract Objectives Isoliquiritigenin (ILQ) is a phenolic compound found in licorice and is a popular dietary supplement. ILQ exhibits model-specific antioxidant, anti-inflammatory, anti-tumor, and estrogenic activities. Limited data suggest the potential of ILQ to prevent or treat osteoporosis. Therefore, this study evaluated the effects of short-duration treatment with ILQ on bone and uterine tissue in estrogen-deplete ovariectomized (ovx) rats. The uterus was important to evaluate because ILQ stimulates proliferation of MCF7 breast cancer cells through an estrogen receptor-dependent mechanism. Methods Six-week-old rats (ovx'd at 4 weeks of age) were fed diets containing 0, 100, 250 or 750 ppm ILQ (n = 5/treatment) for 1 week and sacrificed. Gene expression in femur and uterus, blood markers of global bone turnover, body composition, and uterine weight and epithelial cell height were determined. In addition, the effect of ILQ on in vitro differentiation of osteoclasts derived from bone marrow was assessed. Results Treatment resulted in a dose-dependent increase in serum ILQ with levels reaching 2.4 ± 0.2 mM in rats receiving the highest dose. ILQ did not alter serum levels of osteocalcin, a global marker of bone formation, or osteocalcin gene expression in femur. Additionally, there was little or no effect of ILQ on genes related to osteoblast differentiation or activity in femur. These largely null findings contrast with a reduction in serum CTX, a global marker of bone resorption, at all dose levels of ILQ. At the gene level, ILQ resulted in lower mRNA for genes related to osteoclast differentiation and function in femur, including Acp5 (tartrate resistant acid phosphatase), Timp2 and Mmp2, and suppressed osteoclast differentiation in vitro. ILQ had no effect on the ovx-induced increase in body weight. Ovx resulted in lower uterine weight. Treatment with ILQ at 750 ppm resulted in development of severe uterine epithelial cell hyperplasia in two of five animals. Conclusions ILQ supplementation led to reduced biochemical and gene expression markers of bone resorption in vivo and reduced osteoclast differentiation in vitro without increasing estrogen-dependent gene expression. However, the potential benefits must be weighed against potential detrimental off-target effects, including uterine hypertrophy. Funding Sources NIH [P50AT006268].

Download Full-text

IL-33 Inhibits TNF-α-Induced Osteoclastogenesis and Bone Resorption

International Journal of Molecular Sciences ◽

10.3390/ijms21031130 ◽

2020 ◽

Vol 21 (3) ◽

pp. 1130 ◽

Cited By ~ 8

Author(s):

Fumitoshi Ohori ◽

Hideki Kitaura ◽

Saika Ogawa ◽

Wei-Ren Shen ◽

Jiawei Qi ◽

...

Keyword(s):

Bone Resorption ◽

Nuclear Translocation ◽

Bone Marrow Cells ◽

Bone Destruction ◽

Osteoclast Formation ◽

Tartrate Resistant Acid Phosphatase ◽

Ct Reconstruction ◽

Tnf Α

Interleukin (IL)-33 is a member of the IL-1 family, which acts as an alarmin. Several studies suggested that IL-33 inhibited osteoclastogenesis and bone resorption. Tumor necrosis factor-α (TNF-α) is considered a direct inducer of osteoclastogenesis. However, there has been no report regarding the effect of IL-33 on TNF-α-induced osteoclastogenesis and bone resorption. The objective of this study is to investigate the role of IL-33 on TNF-α-induced osteoclastogenesis and bone resorption. In an in vitro analysis of osteoclastogenesis, osteoclast precursors, which were derived from bone marrow cells, were treated with or without IL-33 in the presence of TNF-α. Tartrate-resistant acid phosphatase (TRAP) staining solution was used to assess osteoclast formation. In an in vivo analysis of mouse calvariae, TNF-α with or without IL-33 was subcutaneously administrated into the supracalvarial region of mice daily for 5 days. Histological sections were stained for TRAP, and osteoclast numbers were determined. Using micro-CT reconstruction images, the ratio of bone destruction area on the calvariae was evaluated. The number of TRAP-positive cells induced by TNF-α was significantly decreased with IL-33 in vitro and in vivo. Bone resorption was also reduced. IL-33 inhibited IκB phosphorylation and NF-κB nuclear translocation. These results suggest that IL-33 inhibited TNF-α-induced osteoclastogenesis and bone resorption.

Download Full-text

Inhibitory Effects of N-[2-(4-acetyl-1-piperazinyl) phenyl]-2-(2-chlorophenoxy) acetamide on Osteoclast Differentiation In Vitro via the Downregulation of TRAF6

International Journal of Molecular Sciences ◽

10.3390/ijms20205196 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5196 ◽

Cited By ~ 5

Author(s):

Zhihao Chen ◽

Eunjin Cho ◽

Jinkyung Lee ◽

Sunwoo Lee ◽

Tae-Hoon Lee

Keyword(s):

Bone Resorption ◽

Mononuclear Cells ◽

Osteoclast Differentiation ◽

Bone Diseases ◽

Marker Genes ◽

Tartrate Resistant Acid Phosphatase ◽

Specific Marker ◽

Potential Candidate ◽

Dependent Manner

Osteoclasts are poly-nuclear cells that resorb mineral components from old or damaged bone tissue. Primary mononuclear cells are activated by receptor activator of nuclear factor kappa-Β ligand (RANKL) and differentiate into large multinucleated cells. Dysregulation of osteoclast differentiation can lead to pathological bone loss and destruction. Many studies have focused on the development of new molecules to regulate RANKL-mediated signaling. In this study, N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(2-chlorophenoxy) acetamide (PPOA-N-Ac-2-Cl) led to a significant decrease in the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells in a dose-dependent manner, without inducing significant cytotoxicity. PPOA-N-Ac-2-Cl affected the expression of osteoclast-specific marker genes, such as TRAF6, c-fos, DC-STAMP, NFATc1, MMP9, CtsK, and TRAP (Acp5), during RANKL-mediated osteoclastogenesis. Moreover, PPOA-N-Ac-2-Cl significantly attenuated the protein levels of CtsK, a critical protease involved in bone resorption. Accordingly, bone resorption activity and F-actin ring formation decreased in the presence of PPOA-N-Ac-2-Cl. In conclusion, this study shows that PPOA-N-Ac-2-Cl acts as an inhibitor of osteoclast differentiation and may serve as a potential candidate agent for the treatment of osteoclast-related bone diseases by virtue of attenuating bone resorption.

Download Full-text

TGFβ1 Regulates Human RANKL-Induced Osteoclastogenesis via Suppression of NFATc1 Expression

International Journal of Molecular Sciences ◽

10.3390/ijms21030800 ◽

2020 ◽

Vol 21 (3) ◽

pp. 800 ◽

Cited By ~ 3

Author(s):

Tokunaga ◽

Mokuda ◽

Kohno ◽

Yukawa ◽

Kuranobu ◽

...

Keyword(s):

Bone Resorption ◽

Transforming Growth Factor ◽

Nuclear Translocation ◽

Osteoclast Differentiation ◽

Magnetic Bead ◽

Tartrate Resistant Acid Phosphatase ◽

Nuclear Factor ◽

Blood Monocytes ◽

Activated T Cells ◽

Gene And Protein Expression

Osteoclasts are multinucleated giant cells responsible for bone resorption. Various mediators involved in osteoclast differentiation have been investigated as possible therapeutic targets for osteoporosis and rheumatoid arthritis (RA). Although transforming growth factor beta1 (TGFβ1) has been described as one such multifunctional cytokine essential for bone remodeling, its effect on osteoclastogenesis remains controversial. Therefore, we sought to examine the effect of TGFβ1 on osteoclast generation induced by receptor activator of nuclear factor (NF)-κB ligand (RANKL) in humans. Peripheral blood monocytes, isolated using magnetic bead sorting, were cultured with macrophage-colony stimulating factor (M-CSF) or RANKL with or without TGFβ1. Tartrate-resistant acid phosphatase (TRAP) staining, as well as bone resorption assays, revealed that TGFβ1 suppressed RANKL-mediated human osteoclast development. Real-time reverse transcription PCR and Western blotting revealed that TGFβ1 reduced the gene and protein expression of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), the master regulator of osteoclast differentiation, respectively. Luciferase assays indicated that TGFβ1 inhibited the NF-κB p65-stimulated promoter activity of NFATc1. Immunofluorescence analysis demonstrated that TGFβ1 abrogated RANKL-induced nuclear translocation of p65. Thus, TGFβ1 regulates human RANKL-induced osteoclastogenesis via downregulation of NFATc1 by blocking nuclear translocation of NF-κB, suggesting that TGFβ1 may be a potential therapeutic target for RA.

Download Full-text

Synovial Fibroblasts Infected with Salmonella enterica Serovar Typhimurium Mediate Osteoclast Differentiation and Activation

Infection and Immunity ◽

10.1128/iai.72.12.7183-7189.2004 ◽

2004 ◽

Vol 72 (12) ◽

pp. 7183-7189 ◽

Cited By ~ 16

Author(s):

Xiang Zhang ◽

Jane E. Aubin ◽

Tae-Hwan Kim ◽

Ursula Payne ◽

Basil Chiu ◽

...

Keyword(s):

Bone Resorption ◽

Salmonella Enterica ◽

Bone Structure ◽

Osteoclast Differentiation ◽

Synovial Fibroblasts ◽

Joint Disease ◽

Tartrate Resistant Acid Phosphatase ◽

Rankl Expression ◽

Serovar Typhimurium

ABSTRACT The mechanisms whereby arthritogenic organisms may induce cartilage and bone erosions in infection-triggered arthritis remain unknown. In this study, we asked whether an arthritogenic organism could contribute to osteoclast differentiation and activation through regulation of the receptor activator of NF-κB ligand (RANKL) in synovial fibroblasts. Rat synovial fibroblasts were infected in vitro with Salmonella enterica serovar Typhimurium and monitored over time. The expression of RANKL in resting and infected synovial fibroblasts was quantified by reverse transcription-PCR and Western blotting. Osteoclast progenitors, isolated from femurs of 8-week-old rats and cultured in the presence of macrophage colony-stimulating factor, were cocultured with either infected or noninfected synovial fibroblasts for 2 to 4 days. Differentiation and maturation of osteoclasts were determined by morphology and tartrate-resistant acid phosphatase (TRAP) staining and by a bone resorption bioassay. RANKL expression was undetectable in resting synovial fibroblasts but was dose-dependently upregulated in cells after Salmonella infection. Osteoprotegerin was constitutively expressed by synovial fibroblasts and was not upregulated by infection. Further, we observed the formation of multinucleated TRAP-positive cells and formation of bone resorption pits in cocultures of bone marrow-derived osteoclast precursors with synovial fibroblasts infected with Salmonella but not with heat-killed Salmonella or noninfected cells. Arthritogenic bacteria may alter bone structure via synovial fibroblast intermediaries, since infected synovial fibroblasts (i) upregulate RANKL expression and (ii) enhance osteoclast precursor maturation into multinucleated, TRAP-positive, bone-resorbing, osteoclast-like cells. These data provide a link between infection and osteoclastogenesis. A better understanding of infection-mediated osteoclast differentiation and activation may provide new therapeutic strategies for inflammatory joint disease.

Download Full-text

The Prenyl Group Contributes to Activities of Phytoestrogen 8-Prenynaringenin in Enhancing Bone Formation and Inhibiting Bone Resorption In Vitro

Endocrinology ◽

10.1210/en.2012-2086 ◽

2013 ◽

Vol 154 (3) ◽

pp. 1202-1214 ◽

Cited By ~ 28

Author(s):

Lei-Guo Ming ◽

Xiang Lv ◽

Xiao-Ni Ma ◽

Bao-Feng Ge ◽

Ping Zhen ◽

...

Keyword(s):

Bone Resorption ◽

Mrna Expression ◽

Bone Marrow Cells ◽

Osteoclast Differentiation ◽

Cathepsin K ◽

Active Role ◽

Osteoclast Formation ◽

Calcium Deposition ◽

Tartrate Resistant Acid Phosphatase

Abstract Previous studies have found that 8-prenylflavonoids have a higher osteogenic activity than do flavonoids, which suggested that the 8-prenyl group may play an active role in bone-protective properties. To address this hypothesis, activities of 8-prenylnaringenin (PNG) and naringenin (NG) in osteoblast and osteoclast differentiation and function were compared in vitro. PNG was found to have a stronger ability than NG to improve osteoblast differentiation and osteogenic function in cultured rat calvarial osteoblasts, as demonstrated by levels of alkaline phosphatase activity, osteocalcin, calcium deposition, and the number and area of mineralized bone nodules, as well as mRNA expression of osteogenesis-related genes Bmp-2, OSX, and Runx-2. In addition, although expression of osteoclastogenic inducer receptor activator of nuclear factor kappa-B ligand (RANKL) was not affected, that of osteoclastogenesis inhibitor osteoprotegerin (OPG) and consequently the OPG/RANKL ratio were increased, more potently by PNG than NG. PNG was also found to have a higher potency than NG in inhibiting the osteoclast formation in rabbit bone marrow cells and their resorptive activity, as revealed by lower numbers of osteoclasts formed, lower numbers and areas of bone resorption pits, and lower mRNA expression levels of tartrate-resistant acid phosphatase and cathepsin K. Furthermore, PNG induced apoptosis of mature osteoclasts at a higher degree and at an earlier time than did NG. These results indicate that the 8-prenyl group plays an important role and contributes to the higher bone-protective activity of PNG in comparison with NG.

Download Full-text

Inhibition Effect of Zoledronate on the Osteoclast Differentiation of RAW264.7 Induced by Titanium Particles

BioMed Research International ◽

10.1155/2021/5578088 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Wenhan Zhao ◽

Zhusong Huang ◽

Yu Lin ◽

Jinfu Lan ◽

Xi Gao

Keyword(s):

Bone Resorption ◽

Protein Expression ◽

Osteoclast Differentiation ◽

Raw264.7 Cells ◽

Blue Staining ◽

Toluidine Blue Staining ◽

Mrna And Protein Expression ◽

Polymerase Chain ◽

Ti Particles

Objective. This study is aimed at studying the effect of zoledronate (ZOL) on the differentiation of osteoclast precursor RAW264.7 cells induced by titanium (Ti) particles and explores the possibility of preventing and treating periprosthetic osteoporosis using ZOL. Methods. RAW264.7 cells were cultured in vitro. Ti particles were prepared. The cell proliferation curve of RAW264.7 cells was plotted using the MTT assay to find the best concentration of ZOL for intervention. The cells were divided into three groups: control, Ti particles, and Ti particles+ZOL. The cell morphology was observed using tartaric acid–resistant acid phosphatase (TRAP) staining, and the activity of TRAP in cell supernatant was determined using the biochemical method. The number of bone resorption lacunae was detected using toluidine blue staining. The mRNA expression of RANK, NFATcl, CAII, and MMP-9 was detected using real-time polymerase chain reaction. The protein expression of RANK, NFATcl, and MMP-9 was detected using Western blot analysis. Results. Ti particles stimulated the differentiation of RAW264.7 cells into osteoclasts. They also increased the activity of TRAP, number of bone resorption lacunae, and mRNA and protein expression of RANK, NFATcl, and MMP-9. However, ZOL could suppress the effect of TI particles on the osteoclast differentiation of RAW264.7 cells. Conclusions. ZOL could effectively inhibit the differentiation of RAW264.7 cells into osteoclasts induced by Ti particles, decrease the activity of TRAP, reduce the number of bone resorption lacunae, and decrease the mRNA and protein expression of RANK, NFATcl, and MMP-9. Hence, it may be a promising candidate for preventing and treating periprosthetic osteoporosis after the artificial joint operation.

Download Full-text

Inactivation of autophagy ameliorates glucocorticoid-induced and ovariectomy-induced bone loss

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2015-207240 ◽

2015 ◽

Vol 75 (6) ◽

pp. 1203-1210 ◽

Cited By ~ 40

Author(s):

Neng-Yu Lin ◽

Chih-Wei Chen ◽

Rosebeth Kagwiria ◽

Ruifang Liang ◽

Christian Beyer ◽

...

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Osteoblast Differentiation ◽

Osteoclast Differentiation ◽

Cathepsin K ◽

Tartrate Resistant Acid Phosphatase ◽

Differentiation Markers ◽

Treatment Of Osteoporosis ◽

The Impact

ObjectivesAutophagy has recently been shown to regulate osteoclast activity and osteoclast differentiation. Here, we aim to investigate the impact of autophagy inhibition as a potential therapeutic approach for the treatment of osteoporosis in preclinical models.MethodsSystemic bone loss was induced in mice by glucocorticoids and by ovariectomy (OVX). Autophagy was targeted by conditional inactivation of autophagy-related gene 7 (Atg7) and by treatment with chloroquine (CQ). Bone density was evaluated by microCT. The role of autophagy on osteoclastogenesis was analysed by osteoclastogenesis and bone resorption assays. The quantification of receptor activator of nuclear factor κ B ligand and osteoprotegerin proteins in cocultures was performed using ELISA whereas that of osteoclast and osteoblast differentiation markers was by qPCR.ResultsSelective deletion of Atg7 in monocytes from Atg7fl/fl_x_LysM-Cre mice mitigated glucocorticoid-induced and OVX-induced osteoclast differentiation and bone loss compared with Atg7fl/fl littermates. Pharmacological inhibition of autophagy by treatment with CQ suppressed glucocorticoid-induced osteoclastogenesis and protected mice from bone loss. Similarly, inactivation of autophagy shielded mice from OVX-induced bone loss. Inhibition of autophagy led to decreased osteoclast differentiation with lower expression of osteoclast markers such as NFATc1, tartrate-resistant acid phosphatase, OSCAR and cathepsin K and attenuated bone resorption in vitro. In contrast, osteoblast differentiation was not affected by inhibition of autophagy.ConclusionsPharmacological or genetic inactivation of autophagy ameliorated glucocorticoid-induced and OVX-induced bone loss by inhibiting osteoclastogenesis. These findings may have direct translational implications for the treatment of osteoporosis, since inhibitors of autophagy such as CQ are already in clinical use.

Download Full-text