골흡수 증가시 tartrate-resistant acid phosphatase 양성세포의 동태 : in Initial Bone Resorption after the Cortical Bone Defect

손승원,김익동,채종민,곽정식,손태중 慶北大學校 醫科大學 1994 慶北醫大誌 Vol.35 No.1

목적 : 골흡수에 중심적인 역할을 하는 파골세포의 유래에 대하여 아직도 많은 논란이 있는 바 최근 tartrate 내성 acid phosphatase라는 효소가 파골세포와 그 전구세포를 인지 할 수 있는 표지자로 사용하게 됨에 따라 파골세포의 분화를 촉진시킨 경우와 억제시킨 경우에서 tartrate 내성 acid phosphatase의 양성세포의 동태를 관찰하여 그 세포의 유래와 골 표면에서의 파골세포의 형성과정을 알아보고저 한다. 대상 및 방법 : Sprague-Dawley계 흰쥐의 경골 앞쪽 전반을 실톱으로 골결손을 만들어 골흡수를 유도한 다음 파골세포의 전구세포로부터 다핵의 파골세포로의 융합내지는 분화를 촉진시키기 위하여 부갑상선 조직을 골결손 부위에 이식시킨 군과 반대로 파골세포의 분화을 억제시키기 위하여 국소적 prostaglandin생산 억제제인 indomethacin을 체중 1㎏당 2㎎을 국소에 매일 주사한 군으로 나누어 실험을 하였다. 골결손을 일으킨 후 제 1 일, 제 2 일, 제 3 일, 제 4 일 및 제 5 일에 경골을 절취하여 광학현미경을 위한 tartrate 내성 acid phosphatase (AcP)염색과 투과전자현미경을 위한 AcP의 조직화학적 염색을 하여 관찰하였다. 결과 : 골결손을 일으킨 후 아무런 처치를 하지 않은 대조군에서는 tartrate 내성 AcP양성의 단핵을 가진 파골세포의 전구세포가 골결손 제 1 일 후부터 나타나기 시작하여 제 2 일 째 가장 많이 나타났다. 제 3 일에서는 다핵을 가진 파골세포가 출현하기 시작하여 제 4 일 째 가장 많이 관찰되었으며 5일 후에는 파골세포의 숫자가 적어졌으며 골결손 주위에 신생 유골이 형성되기 시작하였다. 그리고 파골세포의 전구세포가 나타날 때 골내막의 골아세포 아래 세포층에는 tartrate 내성 AcP음성이면서 단핵의 탐식구들도 많이 출현하여 골결손 제 2 일 째 역시 가장 않은 숫적 증가를 보였다. 이 후 점차 소실되었다. 그리고 골결손을 일으킨 후 부갑상선 조직을 이식한 실험군에서는 골결손 제 1 일 후부터 tartrate 내성 AcP양성의 단핵을 가진 파골세포의 전구세포들과 그 주위에 단구 또는 대식구의 탐식구들이 왕성하게 나타나기 시작하여 제 2 일 째부터 다핵을 가진 파골세포의 출현을 보이며 피질골의 골흡수가 많이 일어났다. AcP의 조직 화학적반응을 한 후 투과전자현미경적 관찰에서 파골세포의 전구세포나 다핵의 이미 형성된 파골세포에 새로이 다른 종류의 탐식구로 보이는 세포들과 밀접하게 접촉내지는 융합하는 과정을 시사하는 소견도 관찰할 수가 있었다. 그러나 prostaglandin의 생산 억제제인 indomethacin을 국소에 매일 주사한 군에서는 골아세포들의 변형이 일어나지 않았으며 이어 파골세포들의 형성 및 활성화가 매우 적어 골흡수가 현저히 억제되었다. tartrate 내성 AcP양성의 단핵의 파골세포의 전구세포들이 골결손 제 3 일 후부터 매우 드물게 출현되었다. 결론 : 골조직 표면에서 파골세포의 전구세포들이 혈구세포인 단구 또는 대식구들과 융합이 이루어질 것으로 추측되며, 부갑상선 호르몬이나 prostaglandin 등의 골흡수 촉진 인자들이 파골세포내의 tartrate내성 AcP의 활성도를 증가시키기며, 단구나 대식구와의 융합을 촉진시킨 것으로 생각된다. 그리고 골조직 표면에서의 파골세포의 분화 융합에는 골아세포가 어떤 인자를 분비하여 매개할 것으로 생각된다. An electron microscopic cytochemical study was carried out to investigate the origin of osteoclast and the mechanism for differentiation of osteoclast precursor around the bone tissue during bone resorption after cortical bone defect. In the present study an incomplete cortical defect was made in the tibial shaft of rats using a bone saw, and thereafter tartrate-resistant acid phosphatase cell population examined under two conditions. When transplantation of the parathyroid tissue was done into medullary cavity of the tibia. For the other condition, indomethacin, one of prostaglandin inhibitors, was administered daily at a dose of 2 ㎎/1 ㎏/day. The animals were sacrified at 1, 2, 3, 4 and 5 days after bone defect. The tibial bones were extirpated and examined tartrate-resistant acid phosphatase cells by light microscopy and ultrastructural acid phosphatase-cyto-chemical study. The results were summarized as follow: In the control groups, the first tartrate-resistant acid phosphatase positive nultinucleated osteoclasts appeared along the endosteal surface 3 days after bone defect, and the highest number of these cells was found 4 days after boine defect. Tartrate-resistant acid phosphatase negative mononuclear cells also incerased 1-2 days before the formation of osteoclasts. In the parathyroid transplantation group, the osteoblast converted to stellate shape and the bone matrix was exposed. Formation of tartrate-resistant acid phosphatase positive osteoclast precursors and multinucleated osteoclasts was markedly incresed. There were findings that macrophage has fused with preexisting osteoclast. In the indomethacin group, on day 2, the osteoblasts did not observed shape change, and osteoclastic bone resorption was inconspicuous. The maturation of tartrate-resistant acid phosphatase positive osteoclast precursors was delayed. The results suggested that macrophages fuse with pre-existing osteoclasts and/or osteoclast precursors around the bone tissue, and the bone resorbing agents stimulate fusion of the osteoclast precursors into multinucleated osteoclasts as well as the tartrate-resistant acid phosphatase activity of the preosteoclasts. The osteoblasts seem to mediate formation of multinucleated osteoclasts around the bone surface.

Effects of Macrophage Colony-Stimulating Factor and Osteoclast Differentiation Factor on Osteoclast Generation and Activity

Kwon, Young-Man,Ko, Seon-Yle,Kim, Se-Won,Kim, Jung-Keun Korean Academy of Oral Biology and the UCLA Dental 2001 International Journal of Oral Biology Vol.26 No.3

Osteoclasts are multinucleated cells responsible for bone resorption. They form by fusion of precursors that are derived from the pluripotent hemopoietic stem cells. Precursor cells differentiate into an osteoclast under the control of 1,25-dihycroxyvitamin D_3 (1,25[OH]_2D_3), parathyroid hormone (PTH), prostaglandin E_2, (PGE_2) and local factors. Recent findings have established that the generation of an osteoclast was dependent on M-CSF and/or ODF. In this study, we demonstrated the effects of M_CSF and a soluble form of ODF (sODF) on the generation of an osteoclast from mouse bone marrow cells in vitro, and effects on the activity of osteoclasts in vitro. The effect of M-CSF and sODF were examined on the generation of an osteoclast, osteoclastic resorption activity and NO production from mouse bone marrow cells in culture. TRAP stain and TRAP activity assay were performed to determine the generation of the osteoclast. TRAP(+) MNCs were detected in order to identify the generation of osteoclasts. Resorption pits were measured to ascertain the activity of the osteoslast. M-CSE, sODF or 10^-8 M1,25[OH]_2D_3 had no effect on the production of NO from mouse bone marrow cells. Numerous multinucleated osteoclasts expressing TRAP formed within 8 days of culture and engaged in extensive resorption pit. Number of TRAP(+) MNCs and area of resorption were dependent on M-CSF and sODF. M-CSF increased the formation of TRAP(+) MNCs compared to sODF treatment. Treatment of various concentrations of sODF and 20 ng/ml M-CSF elicited similar effects of M-CSF alone on the TRAP activity of mouse bone marrow cells. However, treatment of various concentrations of M-CSF and 30 ng/ml sODF significantly increased TRAP activity of mouse bone marrew cells dose dependently. Total resorption area and number of resorption pit slightly increased with both sODF and 10^-8 M 1,25[OH]_2D_3. However, in the treatment of sODF alone, there was no significant difference compared eith the control. Effects of M-CSF and various concentrations of sODF on the total resorption area and nimber of pit were similar to that of 1,25[OH]_2D_3 (10^-8M) except 10ng/ml ODF. However, treatment of various concentration of M-CSF and 30ng/ml sODF significantly increased total resorption area and the number of resorption pit. Average resorption area of M-CSF and sODF treatment was larger than that of M-CSF or sODF alone was not sufficient for an osteoclast generation. In addition, these results indicated that osteoclastogenesis by M-CSF and sODF might not be involved in NO-mediated signal transduction pathway.

(-)-Epigallocatechin gallate induces apoptosis, via caspase activation, in osteoclasts differentiated from RAW 264.7 cells

Yun, J.-H.,Kim, C.-S.,Cho, K.-S.,Chai, J.-K.,Kim, C.-K.,Choi, S.-H. Blackwell Publishing Ltd 2007 Journal of periodontal research Vol.42 No.3

<P>Background and Objective: </P><P>Alveolar bone resorption is a characteristic feature of periodontal diseases and involves removal of both the mineral and the organic constituents of the bone matrix, a process mainly carried out by multinucleated osteoclast cells. (-)-Epigallocatechin gallate, the main constituent of green tea polyphenols, has been reported to induce the apoptotic cell death of osteoclasts and to modulate caspase activation in various tumor cells. In the present study, we investigated the inhibitory effect of (-)-epigallocatechin gallate on osteoclast survival and examined if (-)-epigallocatechin gallate mediates osteoclast apoptosis via caspase activation.</P><P>Material and Methods: </P><P>The effect of (-)-epigallocatechin gallate on osteoclast survival was examined by tartrate-resistant acid phosphatase (TRAP) staining in osteoclasts differentiated from RAW 264.7 cells. In addition, we evaluated the apoptosis of osteoclasts by (-)-epigallocatechin gallate using a DNA-fragmentation assay. Involvement of caspase in (-)-epigallocatechin gallate-mediated osteoclast apoptosis was evaluated by treatment with a general caspase inhibitor, Z-VAD-FMK. Moreover, the effect of (-)-epigallocatechin gallate on the activation of caspase-3 was assessed by a colorimetric activity assay and western blotting.</P><P>Results: </P><P>(-)-Epigallocatechin gallate significantly inhibited, in a dose-dependent manner, the survival of osteoclasts differentiated from RAW 264.7 cells and induced the apoptosis of osteoclasts. Treatment with (-)-epigallocatechin gallate resulted in DNA fragmentation and induced the activation of caspase-3 in RAW 264.7 cell-derived osteoclasts. Additional treatment with Z-VAD-FMK suppressed these effects of (-)-epigallocatechin gallate.</P><P>Conclusion: </P><P>From these findings, we could suggest that (-)-epigallocatechin gallate might prevent alveolar bone resorption by inhibiting osteoclast survival through the caspase-mediated apoptosis.</P>

Identification of Alternatively Spliced Forms of human OSCAR in Osteoclasts

김낙성,박홍용,김현동 대한골대사학회 2012 대한골대사학회지 Vol.19 No.1

Objectives: Osteoclasts are multinucleated giant cells which can resorb bone and differentiated from hematopoietic cells. We have previously reported murine osteoclast-associated receptor (OSCAR) may be an important bone-specific regulator of osteoclast differentiation. We have cloned soluble form of human OSCAR (hOSCAR) and examined the role of hOSCAR on osteoclast differentiation. Methods: Osteoclast differentiation was induced by treatment with macrophage colony-stimulating factor (M-CSF)and receptor activator of nuclear factor kappa B ligand (RANKL) and tartrate-resistant acid phosphatase (TRAP)staining and pit formation were performed. Expression was measured by flow cytometry analysis, Northern and Western blot analysis. Results: hOSCAR is expressed in osteoclast cells and involved in the differentiation of osteoclasts from peripheral blood mononuclear cells (PBMC). Two alternatively spliced forms (soluble hOSCAR [hOSCAR-S]) of hOSCAR were identified from osteoclasts complementary deoxyribonucleic acid (cDNA) library derived from PBMC. Putative transmembrane domain was not found in hOSCAR-S forms and it suggested that these forms might be secreted from osteoclast cells. These secreted forms of hOSCAR attenuated RANKL-induced osteoclast formation and bone resorption. Conclusions: Human osteoclasts express at least five different OSCAR messenger ribonucleic acid (mRNA) isoforms which could play different regulatory roles for differentiation. The secreted forms of hOSCAR might be a negative regulator of membrane-bounded forms of OSCAR. 연구목적: 파골세포는 다핵 세포로서 골흡수를 유발한다. 생쥐에서 OSCAR는 파골세포 분화에서 중요한 역할을 함이 밝혀졌다. 인간 OSCAR의 분비형이 클로닝되었고 이들의 파골세포 분화에서의 역할을 분석하고자 하였다. 연구방법: 파골세포 분화는 M-CSF와 RANKL의 처리에 의해 유도하였으며 TRAP 염색법과 pit 형성도를 측정하였다. 발현 정도는 유세포분석, Northern, 및 Western 분석 방법을 사용하였다. 결 과: 인간 OSCAR는 파골세포에서 발현하였으며 PBMC로부터 유도되는 파골세포 형성에 관여하였다. 선택적 이어맞추기에 의해 만들어진 두 종류의 인간 OSCAR가 확인되었다. 이들은 막관통영역이 없는 구조로서 파골세포로부터분비되는 형태로 존재하였다. 이러한 분비형의 인간 OSCAR는 파골세포 분화 및 골흡수를 저해하였다. 결 론: 인간 OSCAR는 최소 5종류의 구조적아형을 갖고 있으며, 이들은 서로 다른 역할을 하고 있다. 특히 분비형인간 OSCAR는 파골세포 분화에서 음성 조절자로서 역할을 한다.

Inhibitory Effects of Wheat Sprouts Extract on RANKL-Induced Osteoclast Differentiation via Suppressing MAPK and NFATc1 Signaling Pathways

Bok Kyung Han,Hyeock Yoon,Kyeong Hoon Kim,Eui-Cheol Shin,Kwang Suk Ko,Hee-Seok Lee,김영준 한국식품영양과학회 2023 Journal of medicinal food Vol.26 No.7

The maintenance of bone is dependent on both osteoclasts, which break down bone, and osteoblasts, which build new bone. Various bone-related disorders, including osteoporosis, can occur as a result of an imbalance between these two cell types. Prolonged use of currently available bone resorption inhibitors may show side effects. Therefore, developing a novel preventive material which effectively inhibits osteoclast differentiation could be beneficial. This study planned to investigate the inhibitory effect of wheat sprout ethanolic extracts (Saegeumgang [SGG] and Arriheuk [ARH]) on the differentiation of osteoclasts induced by RANKL, as well as the mechanisms why fundamental to these effects. The effects of SGG and ARH on bone resorption and osteoclast differentiation were evaluated using RAW 264.7 cells and assessed through TRAP cell count, pit formation, and activity. The expressions of mRNA and protein were accomplished using western blotting, and reverse transcription quantitative polymerase chain reaction analyses were conducted. SGG and ARH were found to suppress osteoclast differentiation in RANKL-stimulated RAW264.7 cells without causing cytotoxic effects. In addition, treatment with SGG and ARH led to a reduction in the number of cells with positive staining for TRAP and TRAP activity. SGG and ARH treatment dose-dependently decreased the pit area in pit formation assays, showing a notable reduction compared to the pit area created by mature osteoclasts. SGG and ARH inhibited osteoclast activity by 84.9% and 95.7% at 200 lg/mL, respectively. In addition, SGG and ARH suppressed the transcriptional activation of various osteoclast-related genes, such as RANK, NFATc1, cathepsin K, c-Fos, TRAP, matrix metallopeptidase-9, dendritic cell-specific transmembrane protein, ATPase H+ transporting v0 subunit d2, and osteoclast-associated receptor in RAW264.7 cells treated with RANKL. SGG and ARH extracts were found to affect the expression of NFATc1 and genes that are specific to osteoclasts during osteoclast differentiation, suggesting their potential use as functional foods or as therapeutic interventions targeting bone health.

NDRG2 Expression Decreases Tumor-Induced Osteoclast Differentiation by Down-regulating ICAM1 in Breast Cancer Cells

( Bomi Kim ),( Sorim Nam ),( Ji Hyun Lim ),( Jong Seok Lim ) 한국응용약물학회 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.1

Bone matrix is properly maintained by osteoclasts and osteoblasts. In the tumor microenvironment, osteoclasts are increasingly differentiated by the various ligands and cytokines secreted from the metastasized cancer cells at the bone metastasis niche. The activated osteoclasts generate osteolytic lesions. For this reason, studies focusing on the differentiation of osteoclasts are important to reduce bone destruction by tumor metastasis. The N-myc downstream-regulated gene 2 (NDRG2) has been known to contribute to the suppression of tumor growth and metastasis, but the precise role of NDRG2 in osteoclast differentiation induced by cancer cells has not been elucidated. In this study, we demonstrate that NDRG2 expression in breast cancer cells has an inhibitory effect on osteoclast differentiation. RAW 264.7 cells, which are monocytic preosteoclast cells, treated with the conditioned media (CM) of murine breast cancer cells (4T1) expressing NDRG2 are less differentiated into the multinucleated osteoclast-like cells than those treated with the CM of 4T1-WT or 4T1-mock cells. Interestingly, 4T1 cells stably expressing NDRG2 showed a decreased mRNA and protein level of intercellular adhesion molecule 1 (ICAM1), which is known to enhance osteoclast maturation. Osteoclast differentiation was also reduced by ICAM1 knockdown in 4T1 cells. In addition, blocking the interaction between soluble ICAM1 and ICAM1 receptors significantly decreased osteoclastogenesis of RAW 264.7 cells in the tumor environment. Collectively, these results suggest that the reduction of ICAM1 expression by NDRG2 in breast cancer cells decreases osteoclast differentiation, and demonstrate that excessive bone resorption could be inhibited via ICAM1 down-regulation by NDRG2 expression.

Effects of Interleukin-17 on Osteoclast Generation and Activity

Han, Dong-Ho,Ko, Seon-Yle,Kim, Se-Won,Kim, Jung-Keun Korean Academy of Oral Biology and the UCLA Dental 2002 International Journal of Oral Biology Vol.27 No.3

Interleukin-17 (IL-17) is a newly discovered T cell-derived cytokine whose role in osteoclast development has not been fully elucidated. This study was performed to examine a potential role of IL-17 in osteoclast, osteoclastic activity, and nitric oxide (NO) production from various culture systems (culture of mouse bone marrow cells; culture of M-CSF dependent bone marrow [MDBM] cells). Tartrate-resistant acid phosphatase (TRAP) (+) multinucleated cells (MNCs) were detected to identify the generation of osteoclasts. Resorption pits were measured to ascertain the activity of osteoclast. In all culture systems, osteoclasts were not formed in the response to IL-17 only. When mouse bone marrow cells and osteoblasts were cocultured, 1,25-dihydroxycholecalciferol (1,25[OH]_2D_3)-induced osteoclasts were increased significantly by the treatment of 1ng/ml IL-17 but decreased by high concentration of IL-17(100 ng/ml). Treatment with IL-17, tumor necrosis factor (TNF)-α, 1.25[OH]_2D_3, macrophage-colony stimulating factor (M-CSF), or osteoclast differentiation factor (ODF) had no effect on the production of NO from coculture of mouse bone marrow cells and osteoblasts. Treatment with IL-17 in MDBM cell culture stimulated TNF-α induced osteoclasts. Total resorption area and number of resorption pit slightly increased with IL-17 in the MDBM culture. Results from the obseration suggested that IL-17 did not act directly on osteoclast precursors, but increased osteoclast formation indirectly via acting on osteoblast, and enhancing the effects of TNF-on osteoclastogenesis.

치주염 유발 세균 Aggregatibacter actinomycetemcomitans와 Porphyromonas gingivalis에 의한 committed osteoclast precursor 분화 증가

박옥진 ( Ok-jin Park ),권영각 ( Yeongkag Kwon ),윤철희 ( Cheol-heui Yun ),한승현 ( Seung Hyun Han ) 한국미생물생명공학회(구 한국산업미생물학회) 2016 한국미생물·생명공학회지 Vol.44 No.4

치주질환은 만성염증성 질환으로 치조골소실을 일으켜 성인치아상실을 유발하는 요인 중 하나이다. 그람 음성세균인Aggregatibacter actinomycetemcomitans와 Porphyromonas gingivalis는 치주질환환자의 병소에서 쉽게 동정된다. 지질 다당체(Lipopolysaccharide; LPS)는 그람 음성세균의 핵심 독력인자로 알려져 있다. 이러한 세균과 LPS는 파골세포에 의한 골소실을 조절하는 요인 중 하나이다. 그러므로 본 연구에서는 동물모델을 활용하여 A. actinomycetemcomitans와 P. gingivalis의 의한 골소실 여부를 확인하고, 기전규명을 위하여 A. actinomycetemcomitans, P. gingivalis, A. actinomycetemcomitans와 P. gingivalis에서 분리한 LPS에 의한 파골세포분화 영향을 연구하였다. 열사멸한 A. actinomycetemcomitans (HKAa)와 열사멸한 P. gingivalis (HKPg)가 복강으로 투여된 쥐의 대퇴골은 대조군에 비해 감소된 골량을 보여주었다. 이러한 골소실의 증가가 파골세포분화 때문인지 확인하기 위해 파골세포분화를 연구한 결과, bone marrow-derived macrophage (BMM)의 RANKL-매개 파골세포분화를 감소시켰으나, committed osteoclast precursor의 파골세포분화를 유도함을 확인하였다. 세균에 의한 파골세포분화 결과와 동일하게 A. actinomycetemcomitans와 P. gingivalis에서 분리한 LPS 역시 RANKL-매개 파골세 포분화는 감소시키고, committed osteoclast precursor의 파골세포분화를 유도하였다. 결과적으로 치주원인균인 A. actinomycetemcomitans와 P. gingivalis는 committed osteoclast precursor의 파골세포분화를 증가시키는데, 이 세균들의 LPS가 핵심 역할을 수행하는 것으로 판단되며 이를 통해 골 흡수를 유발함을 알 수 있었다. Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis are gram-negative bacteria frequently found in lesions from patients with periodontitis manifesting alveolar bone loss. Lipopolysaccharides are a major virulence factor of gram-negative bacteria. Bone resorption is known to be regulated by bacteria and their virulence factors. In the present study, we investigated the effects of A. actinomycetemcomitans and P. gingivalis on bone resorption. Heat-killed A. actinomycetemcomitans (HKAa) and heatkilled P. gingivalis (HKPg) induced bone loss in the femurs of mice after intraperitoneal administration. HKAa and HKPg augmented the differentiation of committed osteoclast precursors into osteoclasts, while they inhibited the differentiation of bone marrow-derived macrophages into osteoclasts. Concordant with the effects of the heat-killed whole cells, LPS purified from A. actinomycetemcomitans and P. gingivalis also augmented osteoclast differentiation from committed osteoclast precursors but attenuated it from bone marrow-derived macrophages. Taken together, these results suggest that the whole cells and lipopolysaccharides of A. actinomycetemcomitans and P. gingivalis induce the differentiation of committed osteoclast precursors into osteoclasts, potentially contributing to bone resorption in vivo.

A Study on the Involvement of Reactive Oxygen Species in Osteoclast Generation

Kim, Hye-Kyung,Ko, Seun-Yle,Baek, Jeong-Hwa,Kim, Jung-Keun,Kim, Gwan-Shik The Official Publication of Korean Academy of Oral 1996 International Journal of Oral Biology Vol.20 No.1

Recent studies have indicated that reactive oxygen species (ROS) are implicated in osteoclastic bone resorption. In an effort to investigate the role of ROS in the osteoclast formation, mouse bone marrow cells were cultured in the presence of 1,25-dihydroxycholecalciferol (1,25-DHCC) for 7 days. To generate ROS in cultures, xanthine/xanthine oxidase were added to medium. After culture, generated osteoclast-like cells retaining the characteristics of osteoclast such as multinuclearity and positive staining for tartarate-resistant acid phosphatase, were counted. Addition of xanthine/xanthine oxidase to the cultures revealed a tendency to enhance, but not significantly, the osteoclast-like cell generation induced by 1,25-DHCC. However, further supplement of superoxide dismutase - a specific superoxide scavenger - to this culture singificantly increased the generation of osteoclast-like cells. Almost the same pattern of stimulatory effects as xanthine/xanthine oxidase were produced in cultures treated with xanthine alone. Exogenously added H_2O_2 slightly increased 1,25-DHCC-induced generation of osteoclast-like cells, while catalase inhibited, though the changes were not significant. The present study support the notions that ROS are involved in the regulation of osteoclast formation. And these results taken together suggest that several types of bone marrow cells may be responsible for the ROS production in vicinity of differentiating osteoclast progenitor cells and regulating potential in osteoclast formation may not be limited to specific kind(s) of ROS.

Euphorbia factor L1 inhibits osteoclastogenesis by regulating cellular redox status and induces Fas-mediated apoptosis in osteoclast

Hong, Seong-Eun,Lee, Jiae,Seo, Dong-Hyun,In Lee, Hye,Ri Park, Doo,Lee, Gong-Rak,Jo, You-Jin,Kim, Narae,Kwon, Minjung,Shon, Hansem,Kyoung Seo, Eun,Kim, Han-Sung,Young Lee, Soo,Jeong, Woojin PERGAMON PRESS 2017 FREE RADICAL BIOLOGY AND MEDICINE Vol.112 No.-

<P><B>Abstract</B></P> <P>Excessive bone resorption caused by increased osteoclast number or activity leads to a variety of bone diseases including osteoporosis, rheumatoid arthritis and periodontitis. Thus, the therapeutic strategy for these diseases has been focused primarily on the inhibition of osteoclast formation and function. This study shows that euphorbia factor L1 (EFL1), a diterpenoid isolated from <I>Euphorbia lathyris</I>, inhibited osteoclastogenesis and induced osteoclast apoptosis. EFL1 suppressed osteoclast formation and bone resorption at both initial and terminal differentiation stages. EFL1 inhibited receptor activator of NF-κB ligand (RANKL)-induced NFATc1 induction with attenuated NF-κB activation and c-Fos expression. EFL1 decreased the level of reactive oxygen species by scavenging them or activating Nrf2, and inhibited PGC-1β that regulates mitochondria biogenesis. In addition, EFL1 induced apoptosis in differentiated osteoclasts by increasing Fas ligand expression followed by caspase activation. Moreover, EFL1 inhibited inflammation-induced bone erosion and ovariectomy-induced bone loss in mice. These findings suggest that EFL1 inhibits osteoclast differentiation by regulating cellular redox status and induces Fas-mediated apoptosis in osteoclast, and may provide therapeutic potential for preventing or treating bone-related diseases caused by excessive osteoclast.</P> <P><B>Highlights</B></P> <P> <UL> <LI> EFL1 inhibits osteoclastogenesis by suppressing NF-κB and PGC-1β. </LI> <LI> EFL1 reduces cellular ROS level by scavenging them or activating Nrf2. </LI> <LI> EFL1 induces Fas-mediated apoptosis in osteoclasts but not in BMMs. </LI> <LI> EFL1 inhibits inflammation- and ovariectomy-induced bone loss in mice. </LI> <LI> EFL1 could be useful for treating osteoclast-mediated bone diseases. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>