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Deng M, Luo J, Cao H, Li Y, Chen L, Liu G. METTL14 represses osteoclast formation to ameliorate osteoporosis via enhancing GPX4 mRNA stability. ENVIRONMENTAL TOXICOLOGY 2023; 38:2057-2068. [PMID: 37195267 DOI: 10.1002/tox.23829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/19/2023] [Accepted: 05/01/2023] [Indexed: 05/18/2023]
Abstract
Excessive bone resorption by osteoclasts results in the development of multiple bone disorders including osteoporosis. This study aimed to explore the biological function of methyltransferase-like14 (METTL14) in osteoclast formation, as well as its related mechanisms. Expression levels of METTL14, GPX4 and osteoclast-related proteins TRAP, NFATc1, c-Fos were detected by qRT-PCR and Western blotting. The osteoporosis model was established in mice by bilateral ovariectomy (OVX). Bone histomorphology was determined by micro-CT and H&E staining. NFATc1 expression in bone tissues was determined by immunohistochemical staining. Proliferation of primary bone marrow macrophages cells (BMMs) was assessed by MTT assay. Osteoclast formation was observed by TRAP staining. The regulatory mechanism was evaluated by RNA methylation quantification assay, MeRIP-qPCR, dual luciferase reporter assay, and RIP, respectively. METTL14 was down-regulated in the serum samples of postmenopausal osteoporotic women, which was positively associated with bone mineral density (BMD). Osteoclast formation was promoted in OVX-treated METTL14+/- mice as compared with wild-type littermates. Conversely, METTL14 overexpression repressed RANKL-induced osteoclast differentiation of BMMs. Mechanistically, METTL14-mediated m6A modification post-transcriptionally stabilized glutathione peroxidase 4 (GPX4), with the assistance of Hu-Antigen R (HuR). Finally, GPX4 depletion-mediated osteoclast formation in BMMs could be counteracted by METTL14 or HuR overexpression. Collectively, METTL14 inhibits osteoclastogenesis and bone resorption via enhancing GPX4 stability through an m6A-HuR dependent mechanism. Therefore, targeting METTL14 might be a novel promising treatment strategy for osteoporosis.
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Affiliation(s)
- Mingsi Deng
- Department of Stomatology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, People's Republic of China
- Department of Orthodontics, Changsha Stomatology Hospital, Changsha, Hunan, People's Republic of China
| | - Jia Luo
- Changsha Blood Center, Changsha, Hunan, People's Republic of China
| | - Heng Cao
- The Department of Wound Joint Surgery, Affiliated Hospital of Yiyang Medical College, Yiyang, Hunan, People's Republic of China
| | - Yong Li
- Department of Emergency, The Third Xiangya Hospital of Central South University, Changsha, Hunan, People's Republic of China
| | - Liangjian Chen
- Department of Stomatology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, People's Republic of China
| | - Gengyan Liu
- Department of Orthopedics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
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Sutton MM, Duffy MP, Verbruggen SW, Jacobs CR. Osteoclastogenesis requires primary cilia disassembly and can be inhibited by promoting primary cilia formation pharmacologically. Cells Tissues Organs 2023:000531098. [PMID: 37231815 PMCID: PMC10863750 DOI: 10.1159/000531098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
The primary cilium is a solitary, sensory organelle with many roles in bone development, maintenance, and function. In the osteogenic cell lineage, including skeletal stem cells, osteoblasts and osteocytes, the primary cilium plays a vital role in the regulation of bone formation and this has made it a promising pharmaceutical target to maintain bone health. While the role of the primary cilium in the osteogenic cell lineage has been increasingly characterized, little is known about the potential impact of targeting the cilium in relation to osteoclasts, a hematopoietic cell responsible for bone resorption. The objective of this study was to determine whether osteoclasts have a primary cilium and to investigate whether or not the primary cilium of macrophages, osteoclast precursors, serves a functional role in osteoclast formation. Using immunocytochemistry, we showed the macrophages have a primary cilium while osteoclasts lack this organelle. Furthermore, we increased macrophage primary cilia incidence and length using fenoldopam mesylate and found that cells undergoing such treatment showed a significant decrease in the expression of osteoclast markers tartrate-resistant acid phosphatase, cathepsin K, and c-Fos as well as decreased osteoclast formation. This work is the first to show that macrophage primary cilia resorption may be a necessary step for osteoclast differentiation. Since primary cilia and pre-osteoclasts are responsive to fluid flow, we applied fluid flow at magnitudes present in the bone marrow to differentiating cells and found that osteoclastic gene expression by macrophages was not affected by fluid-flow mechanical stimulation, suggesting that the role of the primary cilium in osteoclastogenesis is not a mechanosensory one. The primary cilium has been suggested to play a role in bone formation, and our findings indicate that it may also present a means to regulate bone resorption, presenting a dual benefit of developing ciliary-targeted pharmaceuticals for bone disease.
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Affiliation(s)
- Michael M. Sutton
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
| | - Michael P. Duffy
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stefaan W. Verbruggen
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
- Centre for Predictive in vitro Models, School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Department of Mechanical Engineering and INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK
| | - Christopher R. Jacobs
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
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Song R, He S, Cao Y, Lu Y, Peng Y, Zou H, Tong X, Ran D, Ma Y, Liu Z. Cadmium accelerates autophagy of osteocytes by inhibiting the PI3K/AKT/mTOR signaling pathway. ENVIRONMENTAL TOXICOLOGY 2023. [PMID: 37148155 DOI: 10.1002/tox.23823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 04/18/2023] [Accepted: 04/22/2023] [Indexed: 05/07/2023]
Abstract
Cadmium (Cd) can damage bone cells and cause osteoporosis. Osteocytes are the most numerous bone cells and also important target cells for Cd-induced osteotoxic damage. Autophagy plays important role in the progression of osteoporosis. However, osteocyte autophagy in Cd-induced bone injury is not well characterized. Thus, we established a Cd-induced bone injury model in BALB/c mice and a cellular damage model in MLO-Y4 cells. Aqueous Cd exposure for 16 months showed an increase in plasma alkaline phosphatase (ALP) activity and increase in urine calcium (Ca) and phosphorus (P) concentrations in vivo. Moreover, expression level of autophagy-related microtubule-associated protein 1A/1B-light chain 3 II (LC3II) and autophagy-related 5 (ATG5) proteins were induced, and the expression of sequestosome-1 (p62) was reduced, along with Cd-induced trabecular bone damage. In addition, Cd inhibited the phosphorylation of mammalian target of rapamycin (mTOR), protein kinase B (AKT), and phosphatidylinositol 3-kinase (PI3K). In vitro, 80 μM Cd concentrations exposure upregulated LC3II protein expression, and downregulated of p62 protein expression. Similarly, we found that treatment with 80 μM Cd resulted in a reduction in the phosphorylation levels of mTOR, AKT, and PI3K. Further experiments revealed that addition of rapamycin, an autophagy inducer, enhanced autophagy and alleviated the Cd-induced damage to MLO-Y4 cells. The findings of our study reveal for the first time that Cd causes damage to both bone and osteocytes, as well as induces autophagy in osteocytes and inhibits PI3K/AKT/mTOR signaling, which could be a protective mechanism against Cd-induced bone injury.
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Affiliation(s)
- Ruilong Song
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
- Guangling College, Yangzhou University, Yangzhou, People's Republic of China
| | - Shuangjiang He
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Ying Cao
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Yicheng Lu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Yunwen Peng
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Hui Zou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Xishuai Tong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Di Ran
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Yonggang Ma
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
| | - Zongping Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, People's Republic of China
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