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Zheng T, Lin Z, Jiang G, Chen H, Yang Y, Zeng X. Pogostone attenuates osteolysis in breast cancer by inhibiting the NF-kB and JNK signaling pathways of osteoclast. Life Sci 2023; 328:121611. [PMID: 37068706 DOI: 10.1016/j.lfs.2023.121611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/01/2023] [Accepted: 03/17/2023] [Indexed: 04/19/2023]
Abstract
AIMS Breast cancer is the most prevalent cancer in females, and approximately 70 % of all patients have evidence of metastatic bone disease, which substantially affects the quality of life and survival rate of breast cancer patients. Osteoporosis has become a global public health problem, and the abnormal activation of osteoclasts is the key to the progression of osteoporosis and the key to both diseases lies in the osteoclasts. Effective drug treatments are lacking and there is an urgent need to explore new drugs. MATERIALS AND METHODS We observed the effects of pogostone (PO) on osteoclast differentiation, bone resorption function and other indicators, and F-actin ring formation by using Trap staining, SEM and immunofluorescence, and further explored the targets of pogostone in regulating osteoclast differentiation and function using qPCR and Western Blot. In addition, we used CCK 8, Transwell, and flow cytometry to study the effects of pogostone on proliferation, invasion, migration, and apoptosis of MDA-MB-231 cells. Animal models were also constructed for in vivo validation. KEY FINDINGS Pogostone inhibits osteoclast differentiation, bone resorption, formation of F-actin ring, and the expression of specific genes by attenuated NF-kB degradation and phosphorylation of JNK. In vitro, pogostone suppresses invasion of breast cancer cells, migration, and promotes their apoptosis. In mouse models, pogostone attenuated osteoclast formation and bone resorption, blocked breast cancer cells migration, and supprsed breast cancer-induced osteolysis and ovariectomized (OVX)-mediated osteoporosis. SIGNIFICANCE These biological functions of pogostone make it a potential drug for treatment of breast cancer-associated bone metastasis in the future.
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Affiliation(s)
- Tao Zheng
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhengjun Lin
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Guangyao Jiang
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hongxuan Chen
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yaocheng Yang
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China.
| | - Xiangbin Zeng
- Department of Orthopedics, The Second People's Hospital of Huaihua City, Huaihua, China.
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Liu X, Li F, Dong Z, Gu C, Mao D, Chen J, Luo L, Huang Y, Xiao J, Li Z, Liu Z, Yang Y. Metal-polyDNA nanoparticles reconstruct osteoporotic microenvironment for enhanced osteoporosis treatment. SCIENCE ADVANCES 2023; 9:eadf3329. [PMID: 37531423 PMCID: PMC10396296 DOI: 10.1126/sciadv.adf3329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 06/29/2023] [Indexed: 08/04/2023]
Abstract
Current clinical approaches to osteoporosis primarily target osteoclast biology, overlooking the synergistic role of bone cells, immune cells, cytokines, and inorganic components in creating an abnormal osteoporotic microenvironment. Here, metal-polyDNA nanoparticles (Ca-polyCpG MDNs) composed of Ca2+ and ultralong single-stranded CpG sequences were developed to reconstruct the osteoporotic microenvironment and suppress osteoporosis. Ca-polyCpG MDNs can neutralize osteoclast-secreted hydrogen ions, provide calcium repletion, promote remineralization, and repair bone defects. Besides, the immune-adjuvant polyCpG in MDNs could induce the secretion of osteoclastogenesis inhibitor interleukin-12 and reduce the expression of osteoclast function effector protein to inhibit osteoclast differentiation, further reducing osteoclast-mediated bone resorption. PPi4- generated during the rolling circle amplification reaction acts as bisphosphonate analog and enhances bone targeting of Ca-polyCpG MDNs. In ovariectomized mouse and rabbit models, Ca-polyCpG MDNs prevented bone resorption and promoted bone repair by restoring the osteoporotic microenvironment, providing valuable insights into osteoporosis therapy.
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Affiliation(s)
- Xueliang Liu
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fan Li
- Institute of Functional Nano & Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou, Jiangsu 215123, China
| | - Ziliang Dong
- Department of Orthopaedic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Chao Gu
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Dongsheng Mao
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingqi Chen
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lei Luo
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuting Huang
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jie Xiao
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai 200433, China
| | - Zhanchun Li
- Institute of Functional Nano & Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou, Jiangsu 215123, China
| | - Zhuang Liu
- Department of Orthopaedic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yu Yang
- Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
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Bioactive glass nanoparticles inhibit osteoclast differentiation and osteoporotic bone loss by activating lncRNA NRON expression in the extracellular vesicles derived from bone marrow mesenchymal stem cells. Biomaterials 2022; 283:121438. [DOI: 10.1016/j.biomaterials.2022.121438] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 02/03/2022] [Accepted: 02/22/2022] [Indexed: 12/19/2022]
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4
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Song H, Li X, Zhao Z, Qian J, Wang Y, Cui J, Weng W, Cao L, Chen X, Hu Y, Su J. Reversal of Osteoporotic Activity by Endothelial Cell-Secreted Bone Targeting and Biocompatible Exosomes. NANO LETTERS 2019; 19:3040-3048. [PMID: 30968694 DOI: 10.1021/acs.nanolett.9b00287] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Exosomes, also known as extracellular vesicles, are naturally occurring, biocompatible, and bioacive nanoparticles ranging from 40 to 150 nm in diameter. Bone-secreted exosomes play important roles in bone homeostasis, the interruption of which can lead to diseases such as osteoporosis, rheumatoid arthritis, and osteopetrosis. Though the relationship between vascular and bone homeostasis has been recognized recently, the role of vascular endothelial cell (EC)-secreted exosomes (EC-Exos) in bone homeostasis is not well understood. Herein, we found that EC-Exos show more efficient bone targeting than osteoblast-derived exosomes or bone marrow mesenchymal stem cell-derived exosomes. We also found that EC-Exos can be internalized by bone marrow-derived macrophages (BMMs) to alter their morphology. EC-Exos can inhibit osteoclast activity in vitro and inhibit osteoporosis in an ovariectomized mouse model. Sequencing of exosome miRNA revealed that miR-155 was highly expressed in EC-Exos-treated BMMs. The miR-155 level in EC-Exos was much higher than that in BMMs and ECs, indicating that miR-155 was endogenous cargo of EC-derived vesicles. Blockage of BMMs miR-155 levels reversed the suppression by EC-Exos of osteoclast induction, confirming that exosomal miR-155 may have therapeutic potential against osteoporosis. Taken together, our findings suggest that EC-Exos may be utilized as a bone targeting and nontoxic nanomedicine for the treatment of bone resorption disorders.
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Affiliation(s)
- Hongyuan Song
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine , Shanghai Jiao Tong University , Shanghai 200080 , China
| | - Xiaoqun Li
- Graduate Management Unit, Shanghai Changhai Hospital , Second Military Medical University , Shanghai 200433 , China
| | | | - Jin Qian
- The 11th Team of the fourth Brigade of the Basic Medical Department , Second Military Medical University , Shanghai 200433 , China
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Zhang Y, Wang Z, Xie X, Wang J, Wang Y, Peng QS, Zhang M, Wu D, Liu N, Wang HB, Sun WC. Tatarinan N inhibits osteoclast differentiation through attenuating NF-κB, MAPKs and Ca 2+-dependent signaling. Int Immunopharmacol 2018; 65:199-211. [PMID: 30316078 DOI: 10.1016/j.intimp.2018.09.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 09/17/2018] [Accepted: 09/21/2018] [Indexed: 02/08/2023]
Abstract
Osteoclasts are multinucleated cells that originate from hemopoietic stem cells. Targeting over activated osteoclasts is thought to be an effective therapeutic approach to osteoporosis. In a previous study, we reported that Tatarinan O, a lignin-like compound, suppressed RANKL-induced osteoclastogenesis. In this study, we further examined the effects on osteoclast formation of three lignin-like compounds including Tatarinan N (TN), Tatarinan U (TU) and Tatarinan V (TV), all containing a common structure of asarone. We found that only TN suppressed RANKL-induced osteoclast differentiation, bone resorption pit formation and F-acting ring formation. TU and TV did not influence RANKL-induced osteoclastogenesis. We also found that TN dose-dependently inhibited the expression of osteoclastogenesis-associated genes, including TRAP, cathepsin K and MMP-9. Furthermore, we found that TN down-regulated the key transcription factor NFATc1 and c-Fos by preventing the activation of NF-κB and phosphorylation of MAPKs including ERK1/2 and p38 but not JNK. TN attenuated calcineurin expression via suppression of the Btk-PLCγ2 cascade and reduction of intracellular Ca2+, modulating NFATc1 activation. Taking together, our results indicated that TN might have therapeutic potential for osteoporosis.
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Affiliation(s)
- Yuxin Zhang
- Key Laboratory of Zoonosis, Ministry of Education, The Second Hospital of Jilin University, Changchun, China; Key Laboratory of Molecular Enzymology & Engineering, Ministry of Education, College of Life Science, Jilin University, Changchun, China
| | - Zhi Wang
- Key Laboratory of Molecular Enzymology & Engineering, Ministry of Education, College of Life Science, Jilin University, Changchun, China
| | - Xiaona Xie
- The First Hospital of Jilin University, Changchun, China
| | - Jing Wang
- College of Chemistry and Biology, Beihua University, Jilin, China
| | - Yingjian Wang
- Department of Gynaecology and Obstetrics, China-Japan Union Hospital, Jilin University, Changchun, China
| | - Qi-Sheng Peng
- Key Laboratory of Zoonosis, Ministry of Education, The Second Hospital of Jilin University, Changchun, China
| | - Maolin Zhang
- Key Laboratory of Zoonosis, Ministry of Education, The Second Hospital of Jilin University, Changchun, China
| | - Donglin Wu
- Jilin Provincial Center for Disease Control and Prevention, Changchun, China
| | - Ning Liu
- Key Laboratory of Zoonosis, Ministry of Education, The Second Hospital of Jilin University, Changchun, China.
| | - Hong-Bing Wang
- School of Life Sciences and Technology, Tongji University, Shanghai, China.
| | - Wan-Chun Sun
- Key Laboratory of Zoonosis, Ministry of Education, The Second Hospital of Jilin University, Changchun, China.
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Uehara S, Udagawa N, Kobayashi Y. Non-canonical Wnt signals regulate cytoskeletal remodeling in osteoclasts. Cell Mol Life Sci 2018; 75:3683-3692. [PMID: 30051162 PMCID: PMC6154041 DOI: 10.1007/s00018-018-2881-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/11/2022]
Abstract
Osteoclasts are multinucleated cells responsible for bone resorption. Osteoclasts adhere to the bone surface through integrins and polarize to form actin rings, which are formed by the assembly of podosomes. The area contained within actin rings (also called sealing zones) has an acidic pH, which causes dissolution of bone minerals including hydroxyapatite and the degradation of matrix proteins including type I collagen by the protease cathepsin K. Osteoclasts resorb bone matrices while moving on bone surfaces. Osteoclasts change their cell shapes and exhibit three modes for bone resorption: motile resorbing mode for digging trenches, static resorbing mode for digging pits, and motile non-resorbing mode. Therefore, the actin cytoskeleton is actively remodeled in osteoclasts. Recent studies have revealed that many molecules, such as Rac, Cdc42, Rho, and small GTPase regulators and effectors, are involved in actin cytoskeletal remodeling during the formation of actin rings and resorption cavities on bone slices. In this review, we introduce how these molecules and non-canonical Wnt signaling regulate the bone-resorbing activity of osteoclasts.
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Affiliation(s)
- Shunsuke Uehara
- Department of Biochemistry, Matsumoto Dental University, Nagano, 399-0781, Japan
| | - Nobuyuki Udagawa
- Department of Biochemistry, Matsumoto Dental University, Nagano, 399-0781, Japan
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, 1780 Gobara, Hiro-oka, Shiojiri, Nagano, 399-0781, Japan.
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7
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Wang W, Li M, Luo M, Shen M, Xu C, Xu G, Chen Y, Xia L. Naringenin inhibits osteoclastogenesis through modulation of helper T cells‐secreted IL‐4. J Cell Biochem 2017; 119:2084-2093. [PMID: 28834554 DOI: 10.1002/jcb.26370] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/22/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Wengang Wang
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Mingjun Li
- Department of OncologyThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Ming Luo
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Mingkui Shen
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Chen Xu
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Genzhong Xu
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Yaokun Chen
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
| | - Lei Xia
- Department of OrthopaedicsThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanP.R. China
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8
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Cao J, Lu Q, Liu N, Zhang YX, Wang J, Zhang M, Wang HB, Sun WC. Sciadopitysin suppresses RANKL-mediated osteoclastogenesis and prevents bone loss in LPS-treated mice. Int Immunopharmacol 2017; 49:109-117. [DOI: 10.1016/j.intimp.2017.05.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
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9
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Yamashita T, Udagawa N, Thirukonda GJ, Uehara S, Yamauchi H, Suzuki N, Li F, Kobayashi Y, Takahashi N. Platypus and opossum calcitonins exhibit strong activities, even though they belong to mammals. Gen Comp Endocrinol 2017; 246:270-278. [PMID: 28062306 DOI: 10.1016/j.ygcen.2017.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 01/01/2017] [Accepted: 01/02/2017] [Indexed: 10/20/2022]
Abstract
In mammalian assay systems, calcitonin peptides of non-mammalian species exhibit stronger activity than those of mammals. Recently, comparative analyses of a wide-range of species revealed that platypus and opossum, which diverged early from other mammals, possess calcitonins that are more similar in amino acid sequence to those of non-mammals than mammals. We herein determined whether platypus and opossum calcitonins exhibit similar biological activities to those of non-mammalian calcitonins using an assay of actin ring formation in mouse osteoclasts. We also compared the dose-dependent effects of each calcitonin on cAMP production in osteoclasts. Consistent with the strong similarities in their primary amino acid sequences, platypus and opossum calcitonins disrupted actin rings with similar efficacies to that of salmon calcitonin. Human calcitonin exhibited the weakest inhibitory potency and required a 100-fold higher concentration (EC50=3×10-11M) than that of salmon calcitonin (EC50=2×10-13M). Platypus and opossum calcitonins also induced cAMP production in osteoclast cultures with the same efficacies as that of salmon calcitonin. Thus, platypus and opossum calcitonins exhibited strong biological activities, similar to those of the salmon. In addition, phylogenetic analysis revealed that platypus and opossum calcitonins clustered with the salmon-type group but not human- or porcine-type group. These results suggest that platypus and opossum calcitonins are classified into the salmon-type group, in terms of the biological activities and amino acid sequences.
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Affiliation(s)
- Teruhito Yamashita
- Institute for Oral Science, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan.
| | - Nobuyuki Udagawa
- Department of Oral Biochemistry, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan
| | | | - Shunsuke Uehara
- Department of Oral Biochemistry, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan
| | - Hirose Yamauchi
- Institute for Oral Science, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan; Japan Osteoporosis Foundation, 11-2 Nihonbashi-kobunacho, Chuo-ku, Tokyo 103-0024, Japan
| | - Nobuo Suzuki
- Noto Marine Laboratory, Institute of Nature and Environment Technology, Kanazawa University, 4-1 Ogi, Noto-cho, Ishikawa 927-0553, Japan
| | - Feng Li
- Institute of Nature Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan
| | - Naoyuki Takahashi
- Institute for Oral Science, Matsumoto Dental University, 1780 Hirooka-Gobara, Shiojiri, Nagano 399-0781, Japan
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Pivetta E, Wassermann B, Bulian P, Steffan A, Colombatti A, Polesel J, Spessotto P. Functional osteoclastogenesis: the baseline variability in blood donor precursors is not associated with age and gender. Oncotarget 2016; 6:31889-900. [PMID: 26376614 PMCID: PMC4741648 DOI: 10.18632/oncotarget.5575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 08/15/2015] [Indexed: 02/06/2023] Open
Abstract
Mononuclear osteoclast precursors circulate in the monocyte fraction of peripheral blood and form multinuclear cells with all osteoclastic phenotypic characteristics when cultured in the presence of macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor kB ligand (RANKL). The method to obtain osteoclast precursors from peripheral blood is simple but the number of recovered osteoclasts is often largely insufficient for functional analyses. The original aim of this study was to develop a rapid and efficient method that could overcome the donor variability and enrich the osteoclast precursors from a small volume of peripheral blood as a basis for future clinical studies to correlate the differentiation potential of circulating osteoclast precursors with bone lesions in cancer patients. We improved the efficiency of osteoclastogenesis by reducing isolation and purification times and overcame the use of flow cytometry and immunomagnetic purification procedures. In our culture system the osteoclast number was increased several-fold and the precursors were able to reach a full differentiation within seven days of culture. Both age as well as gender differences in osteoclastogenesis efficiency were no longer evident by processing limited volume blood samples with this simple and rapid method.
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Affiliation(s)
- Eliana Pivetta
- Division of Experimental Oncology 2, Department of Translational Research, CRO-IRCCS, Aviano, Pordenone, Italy
| | - Bruna Wassermann
- Division of Experimental Oncology 2, Department of Translational Research, CRO-IRCCS, Aviano, Pordenone, Italy
| | - Pietro Bulian
- Clinical and Experimental Onco-Hematology Unit, CRO-IRCCS, Aviano, Pordenone, Italy
| | | | - Alfonso Colombatti
- Division of Experimental Oncology 2, Department of Translational Research, CRO-IRCCS, Aviano, Pordenone, Italy
| | - Jerry Polesel
- Unit of Epidemiology and Biostatistics, CRO-IRCSS, Aviano, Pordenone, Italy
| | - Paola Spessotto
- Division of Experimental Oncology 2, Department of Translational Research, CRO-IRCCS, Aviano, Pordenone, Italy
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In vitro model of bone to facilitate measurement of adhesion forces and super-resolution imaging of osteoclasts. Sci Rep 2016; 6:22585. [PMID: 26935172 PMCID: PMC4776281 DOI: 10.1038/srep22585] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/18/2016] [Indexed: 11/08/2022] Open
Abstract
To elucidate processes in the osteoclastic bone resorption, visualise resorption and related actin reorganisation, a combination of imaging technologies and an applicable in vitro model is needed. Nanosized bone powder from matching species is deposited on any biocompatible surface in order to form a thin, translucent, smooth and elastic representation of injured bone. Osteoclasts cultured on the layer expressed matching morphology to ones cultured on sawed cortical bone slices. Resorption pits were easily identified by reflectance microscopy. The coating allowed actin structures on the bone interface to be visualised with super-resolution microscopy along with a detailed interlinked actin networks and actin branching in conjunction with V-ATPase, dynamin and Arp2/3 at actin patches. Furthermore, we measured the timescale of an adaptive osteoclast adhesion to bone by force spectroscopy experiments on live osteoclasts with bone-coated AFM cantilevers. Utilising the in vitro model and the advanced imaging technologies we localised immunofluorescence signals in respect to bone with high precision and detected resorption at its early stages. Put together, our data supports a cyclic model for resorption in human osteoclasts.
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