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Yan X, Zheng J, Ren W, Li S, Yang S, Zhi K, Gao L. O-GlcNAcylation: roles and potential therapeutic target for bone pathophysiology. Cell Commun Signal 2024; 22:279. [PMID: 38773637 PMCID: PMC11106977 DOI: 10.1186/s12964-024-01659-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/10/2024] [Indexed: 05/24/2024] Open
Abstract
O-linked N-acetylglucosamine (O-GlcNAc) protein modification (O-GlcNAcylation) is a critical post-translational modification (PTM) of cytoplasmic and nuclear proteins. O-GlcNAcylation levels are regulated by the activity of two enzymes, O-GlcNAc transferase (OGT) and O‑GlcNAcase (OGA). While OGT attaches O-GlcNAc to proteins, OGA removes O-GlcNAc from proteins. Since its discovery, researchers have demonstrated O-GlcNAcylation on thousands of proteins implicated in numerous different biological processes. Moreover, dysregulation of O-GlcNAcylation has been associated with several pathologies, including cancers, ischemia-reperfusion injury, and neurodegenerative diseases. In this review, we focus on progress in our understanding of the role of O-GlcNAcylation in bone pathophysiology, and we discuss the potential molecular mechanisms of O-GlcNAcylation modulation of bone-related diseases. In addition, we explore significant advances in the identification of O-GlcNAcylation-related regulators as potential therapeutic targets, providing novel therapeutic strategies for the treatment of bone-related disorders.
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Affiliation(s)
- Xiaohan Yan
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China
- School of Stomatology, Qingdao University, Qingdao, 266003, China
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Huangdao District, Qingdao, 266555, Shandong, China
| | - Jingjing Zheng
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China
- Department of Endodontics, the Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Wenhao Ren
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Huangdao District, Qingdao, 266555, Shandong, China
| | - Shaoming Li
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China
- School of Stomatology, Qingdao University, Qingdao, 266003, China
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Huangdao District, Qingdao, 266555, Shandong, China
| | - Shuying Yang
- Department of Basic & Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Keqian Zhi
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China.
- School of Stomatology, Qingdao University, Qingdao, 266003, China.
- Key Lab of Oral Clinical Medicine, the Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Huangdao District, Qingdao, 266555, Shandong, China.
| | - Ling Gao
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao, 266555, China.
- School of Stomatology, Qingdao University, Qingdao, 266003, China.
- Key Lab of Oral Clinical Medicine, the Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
- Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Huangdao District, Qingdao, 266555, Shandong, China.
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2
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Long F. Glucose metabolism in skeletal cells. Bone Rep 2022; 17:101640. [PMID: 36438715 PMCID: PMC9694054 DOI: 10.1016/j.bonr.2022.101640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/15/2022] [Accepted: 11/20/2022] [Indexed: 11/23/2022] Open
Abstract
The mammalian skeleton is integral to whole body physiology with a multitude of functions beyond mechanical support and locomotion, including support of hematopoiesis, mineral homeostasis and potentially other endocrine roles. Formation of the skeleton begins in the embryo and mostly from a cartilage template that is ultimately replaced by bone through endochondrial ossification. Skeletal development and maturation continue after birth in most species and last into the second decade of postnatal life in humans. In the mature skeleton, articular cartilage lining the synovial joint surfaces is vital for bodily movement and damages to the cartilage are a hallmark of osteoarthritis. The mature bone tissue undergoes continuous remodeling initiated with bone resorption by osteoclasts and completed with bone formation from osteoblasts. In a healthy state, the exquisite balance between bone resorption and formation is responsible for maintaining a stable bone mass and structural integrity, while meeting the physiological needs for minerals via controlled release from bone. Disruption of the balance in favor of bone resorption is the root cause for osteoporosis. Whereas osteoclasts pump molar quantities of hydrochloric acid to dissolve the bone minerals in a process requiring ATP hydrolysis, osteoblasts build bone mass by synthesizing and secreting copious amounts of bone matrix proteins. Thus, both osteoclasts and osteoblasts engage in energy-intensive activities to fulfill their physiological functions, but the bioenergetics of those and other skeletal cell types are not well understood. Nonetheless, the past ten years have witnessed a resurgence of interest in studies of skeletal cell metabolism, resulting in an unprecedented understanding of energy substrate utilization and its role in cell fate and activity regulation. The present review attempts to synthesize the current findings of glucose metabolism in chondrocytes, osteoblasts and osteoclasts. Advances with the other relevant cell types including skeletal stem cells and marrow adipocytes will not be discussed here as they have been extensively reviewed recently by others (van Gastel and Carmeliet, 2021). Elucidation of the bioenergetic mechanisms in the skeletal cells is likely to open new avenues for developing additional safe and effective bone therapies.
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Affiliation(s)
- Fanxin Long
- Translational Research Program in Pediatric Orthopedics, The Children's Hospital of Philadelphia, Department of Orthopedic Surgery, University of Pennsylvania, United States of America
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3
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Saranya I, Akshaya R, Selvamurugan N. Regulation of Wnt signaling by non-coding RNAs during osteoblast differentiation. Differentiation 2022; 128:57-66. [DOI: 10.1016/j.diff.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/03/2022]
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4
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Pathophysiology and Emerging Molecular Therapeutic Targets in Heterotopic Ossification. Int J Mol Sci 2022; 23:ijms23136983. [PMID: 35805978 PMCID: PMC9266941 DOI: 10.3390/ijms23136983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/19/2022] [Accepted: 06/22/2022] [Indexed: 12/23/2022] Open
Abstract
The term heterotopic ossification (HO) describes bone formation in tissues where bone is normally not present. Musculoskeletal trauma induces signalling events that in turn trigger cells, probably of mesenchymal origin, to differentiate into bone. The aetiology of HO includes extremely rare but severe, generalised and fatal monogenic forms of the disease; and as a common complex disorder in response to musculoskeletal, neurological or burn trauma. The resulting bone forms through a combination of endochondral and intramembranous ossification, depending on the aetiology, initiating stimulus and affected tissue. Given the heterogeneity of the disease, many cell types and biological pathways have been studied in efforts to find effective therapeutic strategies for the disorder. Cells of mesenchymal, haematopoietic and neuroectodermal lineages have all been implicated in the pathogenesis of HO, and the emerging dominant signalling pathways are thought to occur through the bone morphogenetic proteins (BMP), mammalian target of rapamycin (mTOR), and retinoic acid receptor pathways. Increased understanding of these disease mechanisms has resulted in the emergence of several novel investigational therapeutic avenues, including palovarotene and other retinoic acid receptor agonists and activin A inhibitors that target both canonical and non-canonical signalling downstream of the BMP type 1 receptor. In this article we aim to illustrate the key cellular and molecular mechanisms involved in the pathogenesis of HO and outline recent advances in emerging molecular therapies to treat and prevent HO that have had early success in the monogenic disease and are currently being explored in the common complex forms of HO.
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5
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Ye J, Xiao J, Wang J, Ma Y, Zhang Y, Zhang Q, Zhang Z, Yin H. The Interaction Between Intracellular Energy Metabolism and Signaling Pathways During Osteogenesis. Front Mol Biosci 2022; 8:807487. [PMID: 35155568 PMCID: PMC8832142 DOI: 10.3389/fmolb.2021.807487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022] Open
Abstract
Osteoblasts primarily mediate bone formation, maintain bone structure, and regulate bone mineralization, which plays an important role in bone remodeling. In the past decades, the roles of cytokines, signaling proteins, and transcription factors in osteoblasts have been widely studied. However, whether the energy metabolism of cells can be regulated by these factors to affect the differentiation and functioning of osteoblasts has not been explored in depth. In addition, the signaling and energy metabolism pathways are not independent but closely connected. Although energy metabolism is mediated by signaling pathways, some intermediates of energy metabolism can participate in protein post-translational modification. The content of intermediates, such as acetyl coenzyme A (acetyl CoA) and uridine diphosphate N-acetylglucosamine (UDP-N-acetylglucosamine), determines the degree of acetylation and glycosylation in terms of the availability of energy-producing substrates. The utilization of intracellular metabolic resources and cell survival, proliferation, and differentiation are all related to the integration of metabolic and signaling pathways. In this paper, the interaction between the energy metabolism pathway and osteogenic signaling pathway in osteoblasts and bone marrow mesenchymal stem cells (BMSCs) will be discussed.
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Affiliation(s)
- Jiapeng Ye
- Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Jirimutu Xiao
- Mongolian Medicine College, Inner Mongolia Medical University, Hohhot, China
| | - Jianwei Wang
- Department of Orthopedics and Traumatology, Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Wuxi, China
- *Correspondence: Jianwei Wang, ; Heng Yin,
| | - Yong Ma
- Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Yafeng Zhang
- Department of Orthopedics and Traumatology, Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Wuxi, China
| | - Qiang Zhang
- Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Zongrui Zhang
- Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Heng Yin
- Department of Orthopedics and Traumatology, Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Wuxi, China
- *Correspondence: Jianwei Wang, ; Heng Yin,
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6
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Yuan Y, Guo M, Gu C, Yang Y. The role of Wnt/β-catenin signaling pathway in the pathogenesis and treatment of multiple myeloma (review). Am J Transl Res 2021; 13:9932-9949. [PMID: 34650674 PMCID: PMC8507016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Multiple myeloma (MM) is a refractory hematological malignancy characterized by aberrant accumulation of plasma cells. Patients with MM are susceptible to becoming resistant to chemotherapy, eventually leading to relapse. Progression of MM is largely dependent on the bone marrow microenvironment. Stromal cells in the bone marrow microenvironment secrete Wnt ligands to activate Wnt signaling in MM, which is mediated through the transcription regulator β-catenin. In addition, Wnt/β-catenin pathway encourages osteoblast differentiation and bone formation, dysregulation of which is responsible for proliferation and drug resistance of MM cells. As a result, direct inhibition or silencing of β-catenin or associated genes in the Wnt/β-catenin pathway has been proposed to be an effective therapeutic anti-MM strategy. However, the underlying regulatory mechanism of the Wnt/β-catenin pathway in MM remains to be fully elucidated. Herein, we summarized research advances on the specific genes and molecular biology process of Wnt/β-catenin pathway involved in tumorigenesis of MM, as well as the interaction with bone marrow microenvironment. Additionally, comprehensive summaries of drugs or small molecule inhibitors acting on Wnt/β-catenin pathway and targeting MM were introduced. This review intends to provide an overview of theoretical supports for novel Wnt/β-catenin pathway based treatment strategies in MM.
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Affiliation(s)
- Yuxia Yuan
- Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese MedicineNanjing 210022, Jiangsu, China
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese MedicineNanjing 210023, Jiangsu, China
| | - Mengjie Guo
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese MedicineNanjing 210023, Jiangsu, China
| | - Chunyan Gu
- Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese MedicineNanjing 210022, Jiangsu, China
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese MedicineNanjing 210023, Jiangsu, China
| | - Ye Yang
- Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese MedicineNanjing 210022, Jiangsu, China
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese MedicineNanjing 210023, Jiangsu, China
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7
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Gao Q, Hou Y, Li Z, Hu J, Huo D, Zheng H, Zhang J, Yao X, Gao R, Wu X, Sui L. mTORC2 regulates hierarchical micro/nano topography-induced osteogenic differentiation via promoting cell adhesion and cytoskeletal polymerization. J Cell Mol Med 2021; 25:6695-6708. [PMID: 34114337 PMCID: PMC8278073 DOI: 10.1111/jcmm.16672] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 04/16/2021] [Accepted: 05/08/2021] [Indexed: 12/12/2022] Open
Abstract
Surface topography acts as an irreplaceable role in the long‐term success of intraosseous implants. In this study, we prepared the hierarchical micro/nano topography using selective laser melting combined with alkali heat treatment (SLM‐AHT) and explored the underlying mechanism of SLM‐AHT surface‐elicited osteogenesis. Our results show that cells cultured on SLM‐AHT surface possess the largest number of mature FAs and exhibit a cytoskeleton reorganization compared with control groups. SLM‐AHT surface could also significantly upregulate the expression of the cell adhesion‐related molecule p‐FAK, the osteogenic differentiation‐related molecules RUNX2 and OCN as well as the mTORC2 signalling pathway key molecule Rictor. Notably, after the knocked‐down of Rictor, there were no longer significant differences in the gene expression levels of the cell adhesion‐related molecules and osteogenic differentiation‐related molecules among the three titanium surfaces, and the cells on SLM‐AHT surface failed to trigger cytoskeleton reorganization. In conclusion, the results suggest that mTORC2 can regulate the hierarchical micro/nano topography‐mediated osteogenesis via cell adhesion and cytoskeletal reorganization.
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Affiliation(s)
- Qian Gao
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China.,Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China
| | - Yuying Hou
- Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China
| | - Zhe Li
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
| | - Jinyang Hu
- Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China.,Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dawei Huo
- Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China
| | - Huimin Zheng
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China.,Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China
| | - Junjiang Zhang
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
| | - Xiaoyu Yao
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
| | - Rui Gao
- International Education College, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xudong Wu
- Tianjin Key Laboratory of Medical Epigenetics, Department of Cell Biology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Medical University, Tianjin, China
| | - Lei Sui
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
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8
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Chen M, Han H, Zhou S, Wen Y, Chen L. Morusin induces osteogenic differentiation of bone marrow mesenchymal stem cells by canonical Wnt/β-catenin pathway and prevents bone loss in an ovariectomized rat model. Stem Cell Res Ther 2021; 12:173. [PMID: 33712069 PMCID: PMC7953707 DOI: 10.1186/s13287-021-02239-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/24/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Osteoporosis (OP) is a metabolic bone disease due to the imbalance of osteogenesis and bone resorption, in which, bone marrow mesenchymal stem cells (BMSCs) have a significant effect as the seed cells. Recent research has shown the function of Morusin on inhibiting osteoclast differentiation in vitro. However, whether Morusin can regulate the osteogenic differentiation in addition to the proliferation of BMSCs remains unclear. METHODS BMSCs were isolated from 4-week-old Wistar rats and then treated with different concentrations of Morusin for 3, 5, 7, and 14 days. The proliferation of BMSCs was detected by MTT assay. The effect of Morusin on osteogenic differentiation of BMSCs was detected by RT-qPCR, Western blotting, ALP, and Alizarin Red staining. The effect of Morusin on Wnt/β-catenin signaling pathway was analyzed by RT-qPCR, Western blotting, and immunofluorescence. Finally, in the ovariectomy-induced osteoporosis model, the anti-osteoporosis activity of Morusin was determined by micro-CT, HE, and immunohistochemistry. RESULTS The results showed the function of 2.5-10 μM Morusin in the promotion of the proliferation in addition to osteogenic differentiation of BMSCs. Moreover, it also has an impact in activating the Wnt/β-catenin signaling pathway via inhibition of β-catenin phosphorylation as well as promotion of its nuclear translocation. Upon Dickkopf-related protein-1 (DKK-1, an inhibitor of the Wnt/β-catenin signaling pathway) was added to the Morusin, Morusin had a decreased stimulatory osteogenic effect on BMSCs. Finally, in the rat OP model, we found that Morusin could also exert anti-osteoporosis activity in vivo. CONCLUSIONS This study indicates the ability of Morusin in the promotion of osteogenic differentiation of BMSCs via the activation of Wnt/β-catenin signaling pathway and also shows the potential of Morusin to be an agent for osteoporosis treatment.
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Affiliation(s)
- Ming Chen
- Department of Joint Surgery and Sports medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China
| | - Hui Han
- Department of Joint Surgery and Sports medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China
| | - Siqi Zhou
- Department of Joint Surgery and Sports medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China
- Department of Orthopedics Department, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yinxian Wen
- Department of Joint Surgery and Sports medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China.
| | - Liaobin Chen
- Department of Joint Surgery and Sports medicine, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China.
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9
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Hsiao WY, Jung SM, Tang Y, Haley JA, Li R, Li H, Calejman CM, Sanchez-Gurmaches J, Hung CM, Luciano AK, DeMambro V, Wellen KE, Rosen CJ, Zhu LJ, Guertin DA. The Lipid Handling Capacity of Subcutaneous Fat Is Programmed by mTORC2 during Development. Cell Rep 2020; 33:108223. [PMID: 33027655 PMCID: PMC7607535 DOI: 10.1016/j.celrep.2020.108223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/12/2020] [Accepted: 09/11/2020] [Indexed: 02/08/2023] Open
Abstract
Overweight and obesity are associated with type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and cancer, but all fat is not equal, as storing excess lipid in subcutaneous white adipose tissue (SWAT) is more metabolically favorable than in visceral fat. Here, we uncover a critical role for mTORC2 in setting SWAT lipid handling capacity. We find that subcutaneous white preadipocytes differentiating without the essential mTORC2 subunit Rictor upregulate mature adipocyte markers but develop a striking lipid storage defect resulting in smaller adipocytes, reduced tissue size, lipid re-distribution to visceral and brown fat, and sex-distinct effects on systemic metabolic fitness. Mechanistically, mTORC2 promotes transcriptional upregulation of select lipid metabolism genes controlled by PPARγ and ChREBP, including genes that control lipid uptake, synthesis, and degradation pathways as well as Akt2, which encodes a major mTORC2 substrate and insulin effector. Further exploring this pathway may uncover new strategies to improve insulin sensitivity.
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Affiliation(s)
- Wen-Yu Hsiao
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yuefeng Tang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John A. Haley
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rui Li
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Huawei Li
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Camila Martinez Calejman
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Joan Sanchez-Gurmaches
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Division of Endocrinology, Developmental Biology, Cincinnati Children’s Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Chien-Min Hung
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Amelia K. Luciano
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | - Kathryn E. Wellen
- Center for Clinical and Translational Research, Maine Medical Center, Scarborough, MN 04074, USA,Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Clifford J. Rosen
- Center for Clinical and Translational Research, Maine Medical Center, Scarborough, MN 04074, USA
| | - Lihua Julie Zhu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - David A. Guertin
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA,Lead Contact,Correspondence:
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10
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Sun H, Qiao W, Cui M, Yang C, Wang R, Goltzman D, Jin J, Miao D. The Polycomb Protein Bmi1 Plays a Crucial Role in the Prevention of 1,25(OH) 2 D Deficiency-Induced Bone Loss. J Bone Miner Res 2020; 35:583-595. [PMID: 31725940 DOI: 10.1002/jbmr.3921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 11/06/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022]
Abstract
We analyzed the skeletal phenotypes of heterozygous null Cyp27b1 (Cyp27b1+/- ) mice and their wild-type (WT) littermates to determine whether haploinsufficiency of Cyp27b1 accelerated bone loss, and to examine potential mechanisms of such loss. We found that serum 1,25-dihydroxyvitamin D [1,25(OH)2 D] levels were significantly decreased in aging Cyp27b1+/- mice, which displayed an osteoporotic phenotype. This was accompanied by a reduction of expression of the B lymphoma Moloney murine leukemia virus (Mo-MLV) insertion region 1 (Bmi1) at both gene and protein levels. Using chromatin immunoprecipitation (ChIP)-PCR, electrophoretic mobility shift assay (EMSA) and a luciferase reporter assay, we then showed that 1,25(OH)2 D3 upregulated Bmi1 expression at a transcriptional level via the vitamin D receptor (VDR). To determine whether Bmi1 overexpression in mesenchymal stem cells (MSCs) could correct bone loss induced by 1,25(OH)2 D deficiency, we overexpressed Bmi1 in MSCs using Prx1-driven Bmi1 transgenic mice (Bmi1Tg ) mice. We then compared the bone phenotypes of Bmi1Tg mice on a Cyp27b1+/- background, with those of Cyp27b1+/- mice and with those of WT mice, all at 8 months of age. We found that overexpression of Bmi1 in MSCs corrected the bone phenotype of Cyp27b1+/- mice by increasing osteoblastic bone formation, reducing osteoclastic bone resorption, increasing bone volume, and increasing bone mineral density. Bmi1 overexpression in MSCs also corrected 1,25(OH)2 D deficiency-induced oxidative stress and DNA damage, and cellular senescence of Cyp27b1+/- mice by reducing levels of reactive oxygen species (ROS), elevating serum total superoxide dismutase levels, reducing the percentage of γH2 A.X, p16, IL-1β, and TNF-α-positive cells and decreasing γH2A.X, p16, p19, p53, p21, IL-1β, and IL-6 expression levels. Furthermore, 1,25(OH)2 D stimulated the osteogenic differentiation of MSCs, both ex vivo and in vitro, from WT mice but not from Bmi1-/- mice and 1,25(OH)2 D administration in vivo increased osteoblastic bone formation in WT, but not in Bmi1 -/- mice. Our results indicate that Bmi1, a key downstream target of 1,25(OH)2 D, plays a crucial role in preventing bone loss induced by 1,25(OH)2 D deficiency. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Haijian Sun
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - Wanxin Qiao
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - Min Cui
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - Cuicui Yang
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - Rong Wang
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - David Goltzman
- Calcium Research Laboratory, McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jianliang Jin
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
| | - Dengshun Miao
- State Key Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Key Laboratory for Aging & Disease, Nanjing Medical University, Nanjing, China
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11
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Inducible expression of Wnt7b promotes bone formation in aged mice and enhances fracture healing. Bone Res 2020; 8:4. [PMID: 32047703 PMCID: PMC6997361 DOI: 10.1038/s41413-019-0081-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 10/14/2019] [Accepted: 11/28/2019] [Indexed: 02/07/2023] Open
Abstract
There remain unmet clinical needs for safe and effective bone anabolic therapies to treat aging-related osteoporosis and to improve fracture healing in cases of nonunion or delayed union. Wnt signaling has emerged as a promising target pathway for developing novel bone anabolic drugs. Although neutralizing antibodies against the Wnt antagonist sclerostin have been tested, Wnt ligands themselves have not been fully explored as a potential therapy. Previous work has demonstrated Wnt7b as an endogenous ligand upregulated during osteoblast differentiation, and that Wnt7b overexpression potently stimulates bone accrual in the mouse. The earlier studies however did not address whether Wnt7b could promote bone formation when specifically applied to aged or fractured bones. Here we have developed a doxycycline-inducible strategy where Wnt7b is temporally induced in the bones of aged mice or during fracture healing. We report that forced expression of Wnt7b for 1 month starting at 15 months of age greatly stimulated trabecular and endosteal bone formation, resulting in a marked increase in bone mass. We further tested the effect of Wnt7b on bone healing in a murine closed femur fracture model. Induced expression of Wnt7b at the onset of fracture did not affect the initial cartilage formation but promoted mineralization of the subsequent bone callus. Thus, targeted delivery of Wnt7b to aged bones or fracture sites may be explored as a potential therapy.
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12
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Liu Z, Wang H, He J, Yuan X, Sun W. Rictor ablation in BMSCs inhibits bone metastasis of TM40D cells by attenuating osteolytic destruction and CAF formation. Int J Biol Sci 2019; 15:2448-2460. [PMID: 31595162 PMCID: PMC6775318 DOI: 10.7150/ijbs.37241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/28/2019] [Indexed: 01/06/2023] Open
Abstract
The mTOR complex 2 (mTORC2) is recognized as a promising target for breast cancer treatment. As mTORC2-specific inhibitors do not yet exist, studies into the role of mTORC2 in cancer are performed by deleting Rictor or by RNAi-mediated Rictor silencing. The purpose of this study was to explore the effects of Rictor ablation in bone mesenchymal stromal cells (BMSCs) on bone metastasis of breast cancer. First, female mice with the genotype of Prx1-Cre;Rictorf/f (hereafter RiCKO) or Rictorf/f (as control) were injected intratibially with cells of the breast cancer cell line (TM40D) at 4 months of age. Three weeks later, osteolytic bone destruction was detected in metastatic legs by X-ray and micro-CT. We found that Rictor ablation in BMSCs inhibited TM40D-induced osteolytic bone destruction and resulted in greater bone volume maintenance in vivo. Lower CTX-I serum level, a decreased number of TRAP+ osteoclasts and lower Cathepsin-K expression observed at the tumor-bone interface indicated that osteoclastogenesis was inhibited in RiCKO mice. Additionally, co-culture experiments confirmed that Rictor deletion in BMSCs diminished osteoclast differentiation partly via down regulation of RANKL expression. Furthermore, Rictor deficiency was found to reduce the transition of BMSCs to CAFs coupled with decreased secretion of cytokines (IL-6, RANKL, TGFβ), which resulted in lower chemotaxis and less proliferation in TM40D cells. These results suggest that Rictor ablation in BMSCs plays dual roles in breast cancer bone metastasis: (1) repression of osteolytic bone destruction; (2) inhibition of tumor growth.
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Affiliation(s)
- Zibo Liu
- Department of Anatomy, Histology and Embryology, Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, China
| | - Hui Wang
- Department of Anatomy, Histology and Embryology, Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, China
| | - Jialing He
- Department of Anatomy, Histology and Embryology, Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, China
| | - Xiaoqin Yuan
- Department of Anatomy, Histology and Embryology, Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, China
| | - Weiwei Sun
- Department of Anatomy, Histology and Embryology, Laboratory of Reproductive Medicine, Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, China
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13
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Chen H, Ji X, Lee WC, Shi Y, Li B, Abel ED, Jiang D, Huang W, Long F. Increased glycolysis mediates Wnt7b-induced bone formation. FASEB J 2019; 33:7810-7821. [PMID: 30913395 DOI: 10.1096/fj.201900201rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Wingless/integrated (Wnt) signaling has emerged as a major mechanism for promoting bone formation and a target pathway for developing bone anabolic agents against osteoporosis. However, the downstream events mediating the potential therapeutic effect of Wnt proteins are not fully understood. Previous studies have indicated that increased glycolysis is associated with osteoblast differentiation in response to Wnt signaling, but direct genetic evidence for the importance of glucose metabolism in Wnt-induced bone formation is lacking. Here, we have generated compound transgenic mice to overexpress Wnt family member 7B (Wnt7b) transiently in the osteoblast lineage of postnatal mice, with or without concurrent deletion of the glucose transporter 1 (Glut1), also known as solute carrier family 2, facilitated glucose transporter member 1. Overexpression of Wnt7b in 1-mo-old mice for 1 wk markedly stimulated bone formation, but the effect was essentially abolished without Glut1, even though transient deletion of Glut1 itself did not affect normal bone accrual. Consistent with the in vivo results, Wnt7b increased Glut1 expression and glucose consumption in the primary culture of osteoblast lineage cells, and deletion of Glut1 diminished osteoblast differentiation in vitro. Thus, Wnt7b promotes bone formation in part through stimulating glucose metabolism in osteoblast lineage cells.-Chen, H., Ji, X., Lee, W.-C., Shi, Y., Li, B., Abel, E. D., Jiang, D., Huang, W., Long, F. Increased glycolysis mediates Wnt7b-induced bone formation.
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Affiliation(s)
- Hong Chen
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.,Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Xing Ji
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Wen-Chih Lee
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Yu Shi
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Boer Li
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - E Dale Abel
- Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Dianming Jiang
- Department of Orthopedics, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Huang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fanxin Long
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
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14
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Emerging role of circadian rhythm in bone remodeling. J Mol Med (Berl) 2018; 97:19-24. [PMID: 30446776 DOI: 10.1007/s00109-018-1723-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/07/2018] [Accepted: 11/09/2018] [Indexed: 12/31/2022]
Abstract
The 24-h rhythm of behavioral and physiological processes is a typical biological phenomenon regulated by a group of circadian rhythm genes. Dysfunction of the circadian rhythm can cause a wide range of problems, such as cancer and metabolic diseases. In recent decades, increased understanding of the roles of circadian rhythm genes in the bone remodeling process have been documented, including osteoblastic bone formation, osteoclastic bone resorption, and osteoblast/osteoclast communication. A timely review of the current findings may help to facilitate the new field of circadian rhythmic bone remodeling research. Targeted pharmacological modulation of circadian rhythm genes is a possible therapeutic approach through which to overcome bone remodeling problems in the future.
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15
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Abstract
The adult human skeleton is a multifunctional organ undergoing constant remodeling through the opposing activities of the bone-resorbing osteoclast and the bone-forming osteoblast. The exquisite balance between bone resorption and bone formation is responsible for bone homeostasis in healthy adults. However, evidence has emerged that such a balance is likely disrupted in diabetes where systemic glucose metabolism is dysregulated, resulting in increased bone frailty and osteoporotic fractures. These findings therefore underscore the significance of understanding the role and regulation of glucose metabolism in bone under both normal and pathological conditions. Recent studies have shed new light on the metabolic plasticity and the critical functions of glucose metabolism during osteoclast and osteoblast differentiation. Moreover, these studies have begun to identify intersections between glucose metabolism and the growth factors and transcription factors previously known to regulate osteoblasts and osteoclasts. Here we summarize the current knowledge in the nascent field, and suggest that a fundamental understanding of glucose metabolic pathways in the critical bone cell types may open new avenues for developing novel bone therapeutics.
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Affiliation(s)
- Courtney M Karner
- Department of Orthopaedic Surgery, Duke Orthopaedic Cellular, Developmental, and Genome Laboratories, Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Fanxin Long
- Department of Orthopaedic Surgery, Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63131, USA.
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16
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Moorer MC, Riddle RC. Regulation of Osteoblast Metabolism by Wnt Signaling. Endocrinol Metab (Seoul) 2018; 33:318-330. [PMID: 30112869 PMCID: PMC6145954 DOI: 10.3803/enm.2018.33.3.318] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 07/01/2018] [Accepted: 07/08/2018] [Indexed: 12/13/2022] Open
Abstract
Wnt/β-catenin signaling plays a critical role in the achievement of peak bone mass, affecting the commitment of mesenchymal progenitors to the osteoblast lineage and the anabolic capacity of osteoblasts depositing bone matrix. Recent studies suggest that this evolutionarily-conserved, developmental pathway exerts its anabolic effects in part by coordinating osteoblast activity with intermediary metabolism. These findings are compatible with the cloning of the gene encoding the low-density lipoprotein related receptor-5 (LRP5) Wnt co-receptor from a diabetes-susceptibility locus and the now well-established linkage between Wnt signaling and metabolism. In this article, we provide an overview of the role of Wnt signaling in whole-body metabolism and review the literature regarding the impact of Wnt signaling on the osteoblast's utilization of three different energy sources: fatty acids, glucose, and glutamine. Special attention is devoted to the net effect of nutrient utilization and the mode of regulation by Wnt signaling. Mechanistic studies indicate that the utilization of each substrate is governed by a unique mechanism of control with β-catenin-dependent signaling regulating fatty acid β-oxidation, while glucose and glutamine utilization are β-catenin-independent and downstream of mammalian target of rapamycin complex 2 (mTORC2) and mammalian target of rapamycin complex 1 (mTORC1) activation, respectively. The emergence of these data has provided a new context for the mechanisms by which Wnt signaling influences bone development.
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Affiliation(s)
- Megan C Moorer
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Baltimore Veterans Administration Medical Center, Baltimore, MD, USA.
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17
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mTOR signaling in skeletal development and disease. Bone Res 2018; 6:1. [PMID: 29423330 PMCID: PMC5802487 DOI: 10.1038/s41413-017-0004-5] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/13/2017] [Accepted: 10/23/2017] [Indexed: 02/07/2023] Open
Abstract
The mammalian/mechanistic target of rapamycin (mTOR) is a serine/threonine protein kinase that integrates inputs from nutrients and growth factors to control many fundamental cellular processes through two distinct protein complexes mTORC1 and mTORC2. Recent mouse genetic studies have established that mTOR pathways play important roles in regulating multiple aspects of skeletal development and homeostasis. In addition, mTORC1 has emerged as a common effector mediating the bone anabolic effect of Igf1, Wnt and Bmp. Dysregulation of mTORC1 could contribute to various skeletal diseases including osteoarthritis and osteoporosis. Here we review the current understanding of mTOR signaling in skeletal development and bone homeostasis, as well as in the maintenance of articular cartilage. We speculate that targeting mTOR signaling may be a valuable approach for treating skeletal diseases. Drugs directed at a key cellular signaling pathway could prove useful for treating skeletal diseases. Jianquan Chen from Soochow University in Suzhou, China, and Fanxin Long from Washington University School of Medicine in St. Louis, Missouri, USA, provide an overview of how proteins involved in the mechanistic target of rapamycin (mTOR) signaling pathway sense and integrate a range of environmental cues to regulate bone and cartilage development. In particular, they review the differing roles of the two distinct mTOR-containing protein complexes, mTORC1 and mTORC2. Both seem to mediate bone formation and resorption but in different ways, with implications for how best to treat osteoarthritis, osteoporosis, and other degenerative skeletal diseases. The authors suggest that more specific mTOR inhibitors with minimal side effects are needed to help stimulate bone growth in these diseases.
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18
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Lee WC, Guntur AR, Long F, Rosen CJ. Energy Metabolism of the Osteoblast: Implications for Osteoporosis. Endocr Rev 2017; 38:255-266. [PMID: 28472361 PMCID: PMC5460680 DOI: 10.1210/er.2017-00064] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/25/2017] [Indexed: 01/14/2023]
Abstract
Osteoblasts, the bone-forming cells of the remodeling unit, are essential for growth and maintenance of the skeleton. Clinical disorders of substrate availability (e.g., diabetes mellitus, anorexia nervosa, and aging) cause osteoblast dysfunction, ultimately leading to skeletal fragility and osteoporotic fractures. Conversely, anabolic treatments for osteoporosis enhance the work of the osteoblast by altering osteoblast metabolism. Emerging evidence supports glycolysis as the major metabolic pathway to meet ATP demand during osteoblast differentiation. Glut1 and Glut3 are the principal transporters of glucose in osteoblasts, although Glut4 has also been implicated. Wnt signaling induces osteoblast differentiation and activates glycolysis through mammalian target of rapamycin, whereas parathyroid hormone stimulates glycolysis through induction of insulin-like growth factor-I. Glutamine is an alternate fuel source for osteogenesis via the tricarboxylic acid cycle, and fatty acids can be metabolized to generate ATP via oxidative phosphorylation although temporal specificity has not been established. More studies with new model systems are needed to fully understand how the osteoblast utilizes fuel substrates in health and disease and how that impacts metabolic bone diseases.
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Affiliation(s)
- Wen-Chih Lee
- Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Anyonya R Guntur
- Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Fanxin Long
- Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.,Departments of Medicine and Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine 04074
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19
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Karner CM, Long F. Wnt signaling and cellular metabolism in osteoblasts. Cell Mol Life Sci 2017; 74:1649-1657. [PMID: 27888287 PMCID: PMC5380548 DOI: 10.1007/s00018-016-2425-5] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 12/20/2022]
Abstract
The adult human skeleton is a multifunctional organ undergoing continuous remodeling. Homeostasis of bone mass in a healthy adult requires an exquisite balance between bone resorption by osteoclasts and bone formation by osteoblasts; disturbance of such balance is the root cause for various bone disorders including osteoporosis. To develop effective and safe therapeutics to modulate bone formation, it is essential to elucidate the molecular mechanisms governing osteoblast differentiation and activity. Due to their specialized function in collagen synthesis and secretion, osteoblasts are expected to consume large amounts of nutrients. However, studies of bioenergetics and building blocks in osteoblasts have been lagging behind those of growth factors and transcription factors. Genetic studies in both humans and mice over the past 15 years have established Wnt signaling as a critical mechanism for stimulating osteoblast differentiation and activity. Importantly, recent studies have uncovered that Wnt signaling directly reprograms cellular metabolism by stimulating aerobic glycolysis, glutamine catabolism as well as fatty acid oxidation in osteoblast-lineage cells. Such findings therefore reveal an important regulatory axis between bone anabolic signals and cellular bioenergetics. A comprehensive understanding of osteoblast metabolism and its regulation is likely to reveal molecular targets for novel bone therapies.
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Affiliation(s)
- Courtney M Karner
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63131, USA
- Department of Orthopaedic Surgery, Duke Orthopaedic, Cellular, Developmental and Genome Laboratories, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Fanxin Long
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63131, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63131, USA.
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20
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Inhibitory Effects of Dopamine Receptor D 1 Agonist on Mammary Tumor and Bone Metastasis. Sci Rep 2017; 7:45686. [PMID: 28374823 PMCID: PMC5379485 DOI: 10.1038/srep45686] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/02/2017] [Indexed: 01/01/2023] Open
Abstract
Dopaminergic signaling plays a critical role in the nervous system, but little is known about its potential role in breast cancer and bone metabolism. A screening of ~1,000 biologically active compounds revealed that a selective agonist of dopamine receptor D1 (DRD1), A77636, inhibited proliferation of 4T1.2 mammary tumor cells as well as MDA-MB-231 breast cancer cells. Herein, we examined the effect of A77636 on bone quality using a mouse model of bone metastasis from mammary tumor. A77636 inhibited migration of cancer cells in a DRD1-dependent fashion and suppressed development of bone-resorbing osteoclasts by downregulating NFATc1 through the elevation of phosphorylation of eIF2α. In the mouse model of bone metastasis, A77636 reduced osteolytic lesions and prevented mechanical weakening of the femur and tibia. Collectively, we expect that dopaminergic signaling might provide a novel therapeutic target for breast cancer and bone metastasis.
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21
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Liu DM, Zhao L, Liu TT, Jiao PL, Zhao DD, Shih MS, Tao B, Sun LH, Zhao HY, Liu JM. Rictor/mTORC2 loss in osteoblasts impairs bone mass and strength. Bone 2016; 90:50-8. [PMID: 27262777 DOI: 10.1016/j.bone.2016.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/25/2016] [Accepted: 05/29/2016] [Indexed: 11/26/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a Ser/Thr kinase conserved through evolution that coordinates extra cellular signals associated with cell growth. Main functions of mTOR present in the form of two complexes, namely mTORC1 and mTORC2, which are distinct in their unique components, raptor and rictor. In the current study, using a Cre/loxp system, we found an anabolic effect of mTORC2 signaling on skeleton. Osteoblast differentiation was reduced, with down-regulation of mTORC2 signaling activity in primary cultures of osteoblasts that did not contain rictor. Mice with a specific deletion of rictor in mature osteoblasts showed a significant reduction in lean mass and bone mineral density by dual energy x-ray absorptiometry analysis. Micro-computed tomography, histomorphometric, and molecular biological analyses revealed a marked impairment of the cortical bone mass and microarchitecture, as well as minor changes in trabecular bone, of the Rictorob(-/-) mice. Cortical bone mass and thickness of the femoral mid-shaft were dramatically reduced, with unusual increases in porosity and marrow area in Rictorob(-/-) mice. Thinner trabeculae were found in the L4 vertebrae with relatively normal structural indices of trabecular numbers and separation. A lower rate of bone turnover was observed, as the consequence of the decreased individual osteoblast activity and bone resorption. Furthermore, these changes were associated with significantly decreased bone biomechanical properties. In conclusion, expression of rictor in osteoblasts is essential for the maintenance of normal bone remodeling and microarchitecture, especially for the maintenance of the cortical bone.
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Affiliation(s)
- Dong-Mei Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Lin Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China; Department of Endocrine and Metabolic Diseases, ZhongShan Hospital, FuDan University, Shanghai, China
| | - Ting-Ting Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Pei-Lin Jiao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Dian-Dian Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Mei-Shu Shih
- PharmaLegacy Laboratories Co., Ltd., Shanghai, China
| | - Bei Tao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Li-Hao Sun
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Hong-Yan Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China.
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