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Zhang Y, Xu S, Li K, Tan K, Liang K, Wang J, Shen J, Zou W, Hu L, Cai D, Ding C, Li M, Xiao G, Liu B, Liu A, Bai X. mTORC1 Inhibits NF-κB/NFATc1 Signaling and Prevents Osteoclast Precursor Differentiation, In Vitro and In Mice. J Bone Miner Res 2017; 32:1829-1840. [PMID: 28520214 DOI: 10.1002/jbmr.3172] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 04/28/2017] [Accepted: 05/17/2017] [Indexed: 02/02/2023]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a critical sensor for bone homeostasis and bone formation; however, the role of mTORC1 in osteoclast development and the underlying mechanisms have not yet been fully established. Here, we found that mTORC1 activity declined during osteoclast precursors differentiation in vitro and in vivo. We further targeted deletion of Raptor (mTORC1 key component) or Tsc1 (mTORC1 negative regulator) to constitutively inhibit or activate mTORC1 in osteoclast precursors (monocytes/macrophages), using LyzM-cre mice. Osteoclastic formation was drastically increased in cultures of Raptor deficient bone marrow monocytes/macrophages (BMMs), and Raptor-deficient mice displayed osteopenia with enhanced osteoclastogenesis. Conversely, BMMs lacking Tsc1 exhibited a severe defect in osteoclast-like differentiation and absorptive function, both of which were restored following rapamycin treatment. Importantly, expression of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), transcription factors that are essential for osteoclast differentiation was negatively regulated by mTORC1 in osteoclast lineages. These results provide evidence that mTORC1 plays as a critical role as an osteoclastic differentiation-limiting signal and suggest a potential drawback in treating bone loss-related diseases with mTOR inhibitors clinically. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Yue Zhang
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China.,Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Song Xu
- Deparment of Arthroplasty, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Kai Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Kang Tan
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Kangyan Liang
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jian Wang
- Deparment of Arthroplasty, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Junhui Shen
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wenchong Zou
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Le Hu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Daozhang Cai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Changhai Ding
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China.,Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Mangmang Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Guozhi Xiao
- Department of Biology and Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of China, Shenzhen, China.,Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Bin Liu
- Department of Spine Surgery, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Anling Liu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiaochun Bai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China.,Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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