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Huynh H, Wan Y. mTORC1 impedes osteoclast differentiation via calcineurin and NFATc1. Commun Biol 2018; 1:29. [PMID: 30271915 PMCID: PMC6123628 DOI: 10.1038/s42003-018-0028-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 03/06/2018] [Indexed: 12/26/2022] Open
Abstract
Rapamycins are immunosuppressant and anti-cancer drugs that inhibit the kinase mTOR. Clinically, they often cause bone pain, bone necrosis, and high bone turnover, yet the mechanisms are unclear. Here we show that mTORC1 activity is high in osteoclast precursors but downregulated upon RANKL treatment. Loss-of-function genetic models reveal that while early Raptor deletion in hematopoietic stem cells blunts osteoclastogenesis due to compromised proliferation/survival, late Raptor deletion in osteoclast precursors instead augments osteoclastogenesis. Gain-of-function genetic models by TSC1 deletion in HSCs or osteoclast precursors cause constitutive mTORC1 activation, impairing osteoclastogenesis. Pharmacologically, rapamycin treatment at low but clinically relevant doses exacerbates osteoclast differentiation and bone resorption, leading to bone loss. Mechanistically, RANKL inactivates mTORC1 via calcineurin-mediated mTORC1 dephosphorylation, consequently activating NFATc1 by reducing mTORC1-mediated NFATc1 phosphorylation. These findings uncover biphasic roles of mTORC1 in osteoclastogenesis, dosage-dependent effects of rapamycin on bone, and a previously unrecognized calcineurin-mTORC1-NFATc1 phosphorylation-regulatory signaling cascade.
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Affiliation(s)
- HoangDinh Huynh
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Yihong Wan
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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Shen G, Ren H, Qiu T, Zhang Z, Zhao W, Yu X, Huang J, Tang J, Liang D, Yao Z, Yang Z, Jiang X. Mammalian target of rapamycin as a therapeutic target in osteoporosis. J Cell Physiol 2017; 233:3929-3944. [PMID: 28834576 DOI: 10.1002/jcp.26161] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022]
Abstract
The mechanistic target of rapamycin (mTOR) plays a key role in sensing and integrating large amounts of environmental cues to regulate organismal growth, homeostasis, and many major cellular processes. Recently, mounting evidences highlight its roles in regulating bone homeostasis, which sheds light on the pathogenesis of osteoporosis. The activation/inhibition of mTOR signaling is reported to positively/negatively regulate bone marrow mesenchymal stem cells (BMSCs)/osteoblasts-mediated bone formation, adipogenic differentiation, osteocytes homeostasis, and osteoclasts-mediated bone resorption, which result in the changes of bone homeostasis, thereby resulting in or protect against osteoporosis. Given the likely importance of mTOR signaling in the pathogenesis of osteoporosis, here we discuss the detailed mechanisms in mTOR machinery and its association with osteoporosis therapy.
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Affiliation(s)
- Gengyang Shen
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hui Ren
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Ting Qiu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhida Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenhua Zhao
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiang Yu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jinjing Huang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jingjing Tang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - De Liang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhensong Yao
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhidong Yang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaobing Jiang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Laboratory Affiliated to National Key Discipline of Orthopaedic and Traumatology of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
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Shen G, Ren H, Qiu T, Liang D, Xie B, Zhang Z, Yao Z, Yang Z, Jiang X. Implications of the Interaction Between miRNAs and Autophagy in Osteoporosis. Calcif Tissue Int 2016; 99:1-12. [PMID: 26922423 DOI: 10.1007/s00223-016-0122-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 02/15/2016] [Indexed: 01/08/2023]
Abstract
Imbalances between bone formation and resorption are the primary cause of osteoporosis. However, currently, a detailed molecular mechanism of osteoporosis is not available. Autophagy is the conserved process characterized by degrading and recycling aggregated proteins, intracellular pathogens, and damaged organelles. MicroRNAs (miRNAs) are novel regulatory factors that play important roles in numerous cellular processes, including autophagy, through the posttranscriptional regulation of gene expression. Conversely, autophagy plays a role in the regulation of miRNA homeostasis. Recent advances have revealed that both autophagy and miRNAs are involved in the maintenance of bone homoeostasis, whereas the role of the interaction of miRNAs with autophagy in osteoporosis remains unclear. In this paper, we review previous reports on autophagy, miRNAs, and their interaction in osteoporosis.
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Affiliation(s)
- Gengyang Shen
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Hui Ren
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Ting Qiu
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - De Liang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Bo Xie
- The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhida Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhensong Yao
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Zhidong Yang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China
| | - Xiaobing Jiang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
- Laboratory Affiliated to National Key Discipline of Orthopaedic and Traumatology of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
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ZHANG ZHIGUO, SONG CHANGHENG, ZHANG FANGZHEN, CHEN YANJING, XIANG LIHUA, XIAO GARYGUISHAN, JU DAHONG. Rhizoma Dioscoreae extract protects against alveolar bone loss by regulating the cell cycle: A predictive study based on the protein-protein interaction network. Mol Med Rep 2016; 13:5342-8. [DOI: 10.3892/mmr.2016.5188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/02/2016] [Indexed: 11/05/2022] Open
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5
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Russell RGG. Pharmacological diversity among drugs that inhibit bone resorption. Curr Opin Pharmacol 2015; 22:115-30. [DOI: 10.1016/j.coph.2015.05.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 05/07/2015] [Indexed: 02/08/2023]
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Tchetina EV, Poole AR, Zaitseva EM, Sharapova EP, Kashevarova NG, Taskina EA, Alekseeva LI, Semyonova LA, Glukhova SI, Kuzin AN, Makarov MA, Makarov SA. Differences in Mammalian target of rapamycin gene expression in the peripheral blood and articular cartilages of osteoarthritic patients and disease activity. ARTHRITIS 2013; 2013:461486. [PMID: 23864948 PMCID: PMC3707211 DOI: 10.1155/2013/461486] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/12/2013] [Accepted: 05/12/2013] [Indexed: 01/12/2023]
Abstract
The gene expression of mTOR, autophagy-related ULK1, caspase 3, CDK-inhibitor p21, and TNF α was measured in the peripheral blood of osteoarthritic (OA) patients at different stages of the disease aiming to establish a gene expression profile that might indicate the activity of the disease and joint destruction. Whole blood of 65 OA outpatients, 27 end-stage OA patients, 27 healthy volunteers, and knee articular cartilages of 28 end-stage OA patients and 26 healthy subjects were examined. OA outpatients were subjected to clinical testing, ultrasonography, and radiographic and WOMAC scoring. Protein levels of p70-S6K, p21, and caspase 3 were quantified by ELISA. Gene expression was measured using real-time RT-PCR. Upregulation of mTOR gene expression was observed in PBMCs of 42 OA outpatients ("High mTOR expression subset") and in PBMCs and articular cartilages of all end-stage OA patients. A positive correlation between mTOR gene expression in PBMCs and cartilage was observed in the end-stage OA patients. 23 OA outpatients in the "Low mTOR expression subset" exhibited significantly lower mTOR gene expression in PBMCs compared to healthy controls. These "Low mTOR" subset subjects experienced significantly more pain upon walking, and standing and increased total joint stiffness versus "High mTOR" subset, while the latter more often exhibited synovitis. The protein concentrations of p70-S6K, p21, and caspase 3 in PBMCs were significantly lower in the "Low" subset versus "High" subset and end-stage subjects. Increases in the expression of mTOR in PBMCs of OA patients are related to disease activity, being associated with synovitis more than with pain.
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Affiliation(s)
- Elena V. Tchetina
- Clinical Immunology Department, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - A. Robin Poole
- Department of Surgery, McGill University, Montreal, QC, Canada H3A OG4
| | - Elena M. Zaitseva
- Osteoarthritis Laboratory, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Eugeniya P. Sharapova
- Osteoarthritis Laboratory, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Natalya G. Kashevarova
- Osteoarthritis Laboratory, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Elena A. Taskina
- Osteoarthritis Laboratory, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Liudmila I. Alekseeva
- Osteoarthritis Laboratory, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Liudmila A. Semyonova
- Pathomorphology Department, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Svetlana I. Glukhova
- Statistics Department, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Alexandr N. Kuzin
- Forensic Medicine Service, Moscow City Health Department, Moscow 111020, Russia
| | - Maxim A. Makarov
- Surgery Department, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
| | - Sergey A. Makarov
- Surgery Department, Research Institute of Rheumatology, Russian Academy of Medical Sciences, Moscow 115522, Russia
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