1
|
Muratovic D, Atkins GJ, Findlay DM. Is RANKL a potential molecular target in osteoarthritis? Osteoarthritis Cartilage 2024; 32:493-500. [PMID: 38160744 DOI: 10.1016/j.joca.2023.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 10/09/2023] [Accepted: 10/27/2023] [Indexed: 01/03/2024]
Abstract
OBJECTIVE Osteoarthritis (OA) is a disease of joints, in which the bone under the articular cartilage undergoes increased remodelling activity. The question is whether a better understanding of the causes and mechanisms of bone remodelling can predict disease-modifying treatments. DESIGN This review summarises the current understanding of the aetiology of OA, with an emphasis on events in the subchondral bone (SCB), and the cells and cytokines involved, to seek an answer to this question. RESULTS SCB remodelling across OA changes the microstructure of the SCB, which alters the load-bearing properties of the joint and seems to have an important role in the initiation and progression of OA. Bone remodelling is tightly controlled by numerous cytokines, of which Receptor Activator of NFκB ligand (RANKL) and osteoprotegerin are central factors in almost all known bone conditions. In terms of finding therapeutic options for OA, an important question is whether controlling the rate of SCB remodelling would be beneficial. The role of RANKL in the pathogenesis and progression of OA and the effect of its neutralisation remain to be clarified. CONCLUSIONS This review further makes the case for SCB remodelling as important in OA and for additional study of RANKL in OA, both its pathophysiological role and its potential as an OA disease target.
Collapse
Affiliation(s)
- Dzenita Muratovic
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia; Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - Gerald J Atkins
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia; Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - David M Findlay
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| |
Collapse
|
2
|
Zhang Z, Dong L, Tao H, Dong Y, Xiang W, Tao F, Zhao Y. RNA-binding proteins potentially regulate the alternative splicing of apoptotic genes during knee osteoarthritis progression. BMC Genomics 2024; 25:293. [PMID: 38504181 PMCID: PMC10949708 DOI: 10.1186/s12864-024-10181-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND Alternative splicing (AS) is a principal mode of genetic regulation and one of the most widely used mechanisms to generate structurally and functionally distinct mRNA and protein variants. Dysregulation of AS may result in aberrant transcription and protein products, leading to the emergence of human diseases. Although considered important for regulating gene expression, genome-wide AS dysregulation, underlying mechanisms, and clinical relevance in knee osteoarthritis (OA) remain unelucidated. Therefore, in this study, we elucidated and validated AS events and their regulatory mechanisms during OA progression. RESULTS In this study, we identified differentially expressed genes between human OA and healthy meniscus samples. Among them, the OA-associated genes were primarily enriched in biological pathways such as extracellular matrix organization and ossification. The predominant OA-associated regulated AS (RAS) events were found to be involved in apoptosis during OA development. The expression of the apoptosis-related gene BCL2L13, XAF1, and NF2 were significantly different between OA and healthy meniscus samples. The construction of a covariation network of RNA-binding proteins (RBPs) and RAS genes revealed that differentially expressed RBP genes LAMA2 and CUL4B may regulate the apoptotic genes XAF1 and BCL2L13 to undergo AS events during OA progression. Finally, RT-qPCR revealed that CUL4B expression was significantly higher in OA meniscus samples than in normal controls and that the AS ratio of XAF1 was significantly different between control and OA samples; these findings were consistent with their expected expression and regulatory relationships. CONCLUSIONS Differentially expressed RBPs may regulate the AS of apoptotic genes during knee OA progression. XAF1 and its regulator, CUL4B, may serve as novel biomarkers and potential therapeutic targets for this disease.
Collapse
Affiliation(s)
- Zheng Zhang
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China.
| | - Limei Dong
- School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, Hubei, China
| | - Hai Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Yusong Dong
- School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, Hubei, China
| | - Wei Xiang
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Fenghua Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Yingchun Zhao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| |
Collapse
|
3
|
Zelmer AR, Starczak Y, Solomon LB, Richter K, Yang D, Atkins GJ. Saos-2 cells cultured under hypoxia rapidly differentiate to an osteocyte-like stage and support intracellular infection by Staphylococcus aureus. Physiol Rep 2023; 11:e15851. [PMID: 37929653 PMCID: PMC10626491 DOI: 10.14814/phy2.15851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/02/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023] Open
Abstract
The intracellular infection of osteocytes represents a clinically important aspect of osteomyelitis. However, few human osteocyte in vitro models exist and the differentiation of immature osteoblasts to an osteocyte stage typically takes at least 4-weeks of culture, making the study of this process challenging and time consuming. The osteosarcoma cell line Saos-2 has proved to be a useful model of human osteoblast to mature osteocyte differentiation. Culture under osteogenic conditions in a standard normoxic (21% O2 ) atmosphere results in reproducible mineralization and acquisition of mature osteocyte markers over the expected 28-35 day culture period. In order to expedite experimental assays, we tested whether reducing available oxygen to mimic concentrations experienced by osteocytes in vivo would increase the rate of differentiation. Cells cultured under 1% O2 exhibited maximal mineral deposition by 14 days. Early (COLA1, MEPE) and mature (PHEX, DMP1, GJA1, SOST) osteocyte markers were upregulated earlier under hypoxia compared to normoxia. Cells differentiated under 1% O2 for 14 days displayed a similar ability to internalize Staphylococcus aureus as day 28 cells grown under normoxic conditions. Thus, low oxygen accelerates Saos-2 osteocyte differentiation, resulting in a useful human osteocyte-like cell model within 14 days.
Collapse
Affiliation(s)
- Anja R. Zelmer
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Yolandi Starczak
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Lucian B. Solomon
- Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Department of Orthopaedics and TraumaRoyal Adelaide HospitalAdelaideSouth AustraliaAustralia
| | - Katharina Richter
- Richter Lab, Department of SurgeryBasil Hetzel Institute for Translational Health Research, University of AdelaideAdelaideSouth AustraliaAustralia
| | - Dongqing Yang
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Gerald J. Atkins
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
| |
Collapse
|
4
|
The Effects of Vitamin E Analogues α-Tocopherol and γ-Tocotrienol on the Human Osteocyte Response to Ultra-High Molecular Weight Polyethylene Wear Particles. PROSTHESIS 2022. [DOI: 10.3390/prosthesis4030039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polyethylene (PE) liners are a common bearing surface of orthopaedic prostheses. Wear particles of ultra-high molecular weight PE (UHMWPE) contribute to periprosthetic osteolysis, a major cause of aseptic loosening. Vitamin E is added to some PE liners to prevent oxidative degradation. Osteocytes, an important cell type for controlling both bone mineralisation and bone resorption, have been shown to respond UHMWPE particles by upregulating pro-osteoclastogenic and osteocytic osteolysis. Here, we examined the effects of the vitamin E analogues α-tocopherol and γ-tocotrienol alone or in the context of UHMWPE particles on human osteocyte gene expression and mineralisation behaviour. Human osteoblasts differentiated to an osteocyte-like stage were exposed to UHMWPE wear particles in the presence or absence of either α-Tocopherol or γ-Tocotrienol. Both α-Tocopherol and γ-Tocotrienol induced antioxidant-related gene expression. UHMWPE particles independently upregulated antioxidant gene expression, suggesting an effect of wear particles on oxidative stress. Both vitamin E analogues strongly induced OPG mRNA expression and γ-Tocotrienol also inhibited RANKL mRNA expression, resulting in a significantly reduced RANKL:OPG mRNA ratio (p < 0.01) overall. UHMWPE particles reversed the suppressive effect of α-Tocopherol but not of γ-Tocotrienol on this pro-osteoclastogenic index. UHMWPE particles also upregulated osteocytic-osteolysis related gene expression. Vitamin E analogues alone or in combination with UHMWPE particles also resulted in upregulation of these genes. Consistent with this, both vitamin E analogues promoted calcium release from mineralised cultures of osteocyte-like cells. Our findings suggest that while vitamin E may suppress osteocyte support of osteoclastogenesis in the presence of UHMWPE particles, the antioxidant effect may induce osteocytic osteolysis, which could promote periprosthetic osteolysis. It will be important to conduct further studies of vitamin E to determine the long-term effects of its inclusion in prosthetic materials.
Collapse
|
5
|
Muratovic D, Findlay DM, Quarrington RD, Cao X, Solomon LB, Atkins GJ, Kuliwaba JS. Elevated levels of active Transforming Growth Factor β1 in the subchondral bone relate spatially to cartilage loss and impaired bone quality in human knee osteoarthritis. Osteoarthritis Cartilage 2022; 30:896-907. [PMID: 35331858 DOI: 10.1016/j.joca.2022.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 03/03/2022] [Accepted: 03/09/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The association between the spatially distributed level of active TGFβ1 in human subchondral bone, and the characteristic structural and cellular parameters of human knee OA, was assessed. DESIGN Paired subchondral bone samples from 35 OA arthroplasty patients, (15 men and 20 women, aged 69 ± 9 years) were obtained from beneath macroscopically present (CA+) or denuded cartilage (CA-) to determine the concentration of active TGFβ1 (ELISA) and its relationship to bone quality (synchrotron micro-CT), cellularity, and vascularization (histology). RESULTS Bone samples beneath (CA-) regions had significantly increased concentrations of active TGFβ1 protein (mean difference: 26.4; 95% CI: [3.2, 49.7]), when compared to bone in CA + regions. Trabecular Bone below (CA-) regions had increased bone volume (median difference: 4.3; 96.49% CI: [-1.7, 17.8]), increased trabecular number (1.5 [0.006, 2.6], decreased trabecular separation (-0.05 [-0.1,-0.005]), and increased bone mineral density (394.5 [65.7, 723.3]) comparing to (CA+) regions. Further, (CA-) bone regions showed increased osteocyte density (0.012 [0.006, 0.018]), with larger osteocyte lacunae (39.8 [7.8, 71.7]) that were less spherical (-0.02 [-0.04, -0.003]), and increased bone matrix vascularity (12.4 [0.3, 24.5]) compared to (CA+). In addition, increased levels of active TGFβ1 related to increased bone volume (0.04 [-0.11, 0.9]), while increased OARSI grade associated with lacunar volume (-44.1 [-71.1, -17.2]), and orientation (2.7 [0.8, 4.6]). CONCLUSION Increased concentration of active TGFβ1 in the subchondral bone of human knee OA associates spatially with impaired bone quality and disease severity, suggesting that TGFβ1 is a potential therapeutic target to prevent or reduce human OA disease progression.
Collapse
Affiliation(s)
- D Muratovic
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - D M Findlay
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - R D Quarrington
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - X Cao
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - L B Solomon
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia; Orthopaedic and Trauma Service, The Royal Adelaide Hospital and the Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia.
| | - G J Atkins
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| | - J S Kuliwaba
- Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, South Australia 5000, Australia.
| |
Collapse
|
6
|
Bailey KN, Alliston T. At the Crux of Joint Crosstalk: TGFβ Signaling in the Synovial Joint. Curr Rheumatol Rep 2022; 24:184-197. [PMID: 35499698 PMCID: PMC9184360 DOI: 10.1007/s11926-022-01074-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW The effect of the transforming growth factor beta (TGFβ) signaling pathway on joint homeostasis is tissue-specific, non-linear, and context-dependent, representing a unique complexity in targeting TGFβ signaling in joint disease. Here we discuss the variety of mechanisms that TGFβ signaling employs in the synovial joint to maintain healthy joint crosstalk and the ways in which aberrant TGFβ signaling can result in joint degeneration. RECENT FINDINGS Osteoarthritis (OA) epitomizes a condition of disordered joint crosstalk in which multiple joint tissues degenerate leading to overall joint deterioration. Synovial joint tissues, such as subchondral bone, articular cartilage, and synovium, as well as mesenchymal stem cells, each demonstrate aberrant TGFβ signaling during joint disease, whether by excessive or suppressed signaling, imbalance of canonical and non-canonical signaling, a perturbed mechanical microenvironment, or a distorted response to TGFβ signaling during aging. The synovial joint relies upon a sophisticated alliance among each joint tissue to maintain joint homeostasis. The TGFβ signaling pathway is a key regulator of the health of individual joint tissues, and the subsequent interaction among these different joint tissues, also known as joint crosstalk. Dissecting the sophisticated function of TGFβ signaling in the synovial joint is key to therapeutically interrogating the pathway to optimize overall joint health.
Collapse
Affiliation(s)
- Karsyn N Bailey
- Department of Orthopaedic Surgery, University of California San Francisco, 513 Parnassus Avenue, CA, 94143, San Francisco, USA
- UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, 513 Parnassus Avenue, CA, 94143, San Francisco, USA.
| |
Collapse
|
7
|
Wang Y, Zhang T, Xu Y, Chen R, Qu N, Zhang B, Xia C. Suppressing phosphoinositide-specific phospholipases Cγ1 promotes mineralization of osteoarthritic subchondral bone osteoblasts via increasing autophagy, thereby ameliorating articular cartilage degeneration. Bone 2022; 154:116262. [PMID: 34813965 DOI: 10.1016/j.bone.2021.116262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/11/2021] [Accepted: 11/16/2021] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Phosphoinositide-specific phospholipases C-γ1 (PLC-γ1) signaling has been shown to modulate osteoarthritis (OA) chondrocyte metabolism. However, the role of PLC-γ1 in OA osteoblasts remains unclear. Herein, whether and how PLC-γ1 was involved in mineralization in OA subchondral bone osteoblasts were investigated. METHODS Primary non-OA and OA osteoblasts of human and rat isolated from the subchondral bone or the calvaria were cultured in vitro, as well as mouse pre-osteoblastic cell line MC3T3-E1 cells. Rat knee OA model was induced by anterior cruciate ligament transection (ACLT), in which bone canal was carried out from the surface of lateral epicondyle of femur using micro-electric drill. Morphological characteristics of subchondral bone structure and articular cartilage were assessed using CT, micro-CT, and Safranin O/Fast green staining, respectively. Mineralization was measured by alizarin red staining. The expression and production of genes involved in osteoblastic phenotype and mineralization were evaluated by qPCR, western blotting, and immunohistochemistry assays, respectively. The inhibitions were performed using inhibitors and ShRNAs. RESULTS The decreased relative bone density and thickness in the early stage of OA and the increased one in the late stage of OA were observed in subchondral bone of ACLT-rat model. Decreased ALP and OCN levels and absorbance values of ARS content were observed in in vitro osteoblasts isolated from 2 w post-ACLT rat model, as well as IL-1β-treated (for maintaining and mimicking inflammatory status) human OA and rat osteoblasts. Decreased Atg7 level and LC3BII/I ratio in combination with an increase in the P62 level, was concomitant with decreased ALP and OCN mRNA levels and absorbance values of ARS content in OA or IL-1β-treated osteoblasts. Specific inhibition of PLC-γ1 by ShRNAs or inhibitor (U73122) elevated ALP and OCN mRNA levels and absorbance values of ARS content accompanied with increased Atg7 level and LC3BII/I ratio in combination with a decrease in the P62 level in OA osteoblasts. Furthermore, the promoting effect of PLC-γ1 inhibition on ALP and OCN mRNA levels and absorbance values of ARS content was reversed by endoplasmic reticulum (ER) stress activator HA15, as well as autophagic inhibitors CQ and 3MA. Injection with PLC-γ1 inhibitor U73122 from the surface of lateral epicondyle of femur reduced aberrant subchondral bone formation and attenuated articular cartilage degeneration in ACLT-rat. CONCLUSION Aberrant changes of OA subchondral bone structure were concomitant with altered osteoblastic phenotype and mineralization. Impaired autophagy contributed to decreased osteoblastic mineralization in the early stage of OA. PLC-γ1 inhibition promoted osteoblastic mineralization through increasing autophagy in OA osteoblasts, which was partially attributed to suppression of ER stress. Targeting PLC-γ1 in subchondral bone osteoblasts could be more efficacious for OA therapy through treating the bone and cartilage at the same time. In summary, we hypothesize that suppressing PLCγ1 promotes mineralization of osteoarthritic subchondral bone osteoblasts via increasing autophagy, thereby ameliorating articular cartilage degeneration.
Collapse
Affiliation(s)
- Yue Wang
- Bone & Joint Research Institute, Zhongshan Hospital, Xiamen University, Xiamen, Fujian, China
| | - Tongen Zhang
- Bone & Joint Research Institute, Zhongshan Hospital, Xiamen University, Xiamen, Fujian, China
| | - Yang Xu
- Bone & Joint Research Institute, Zhongshan Hospital, Xiamen University, Xiamen, Fujian, China
| | - Rui Chen
- School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Ning Qu
- School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Bing Zhang
- School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Chun Xia
- Bone & Joint Research Institute, Zhongshan Hospital, Xiamen University, Xiamen, Fujian, China.
| |
Collapse
|
8
|
Jiang A, Xu P, Sun S, Zhao Z, Tan Q, Li W, Song C, Leng H. Cellular alterations and crosstalk in the osteochondral joint in osteoarthritis and promising therapeutic strategies. Connect Tissue Res 2021; 62:709-719. [PMID: 33397157 DOI: 10.1080/03008207.2020.1870969] [Citation(s) in RCA: 7] [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: 09/04/2020] [Accepted: 12/28/2020] [Indexed: 02/03/2023]
Abstract
Osteoarthritis (OA) is a joint disorder involving cartilage degeneration and subchondral bone sclerosis. The bone-cartilage interface is implicated in OA pathogenesis due to its susceptibility to mechanical and biological factors. The crosstalk between cartilage and the underlying subchondral bone is elevated in OA due to multiple factors, such as increased vascularization, porosity, microcracks and fissures. Changes in the osteochondral joint are traceable to alterations in chondrocytes and bone cells (osteoblasts, osteocytes and osteoclasts). The phenotypes of these cells can change with the progression of OA. Aberrant intercellular communications among bone cell-bone cell and bone cell-chondrocyte are of great importance and might be the factors promoting OA development. An appreciation of cellular phenotypic changes in OA and the mechanisms by which these cells communicate would be expected to lead to the development of targeted drugs with fewer side effects.
Collapse
Affiliation(s)
- Ai Jiang
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| | - Peng Xu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Shang Sun
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| | - Zhenda Zhao
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| | - Qizhao Tan
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| | - Weishi Li
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education Lisbon Portugal
| | - Chunli Song
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
- Beijing Key Lab of Spine Diseases, Beijing, China
| | - Huijie Leng
- Department of Orthopaedics, Peking University Third Hospital, Beijing, China
| |
Collapse
|
9
|
Suthon S, Perkins RS, Bryja V, Miranda-Carboni GA, Krum SA. WNT5B in Physiology and Disease. Front Cell Dev Biol 2021; 9:667581. [PMID: 34017835 PMCID: PMC8129536 DOI: 10.3389/fcell.2021.667581] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/09/2021] [Indexed: 12/20/2022] Open
Abstract
WNT5B, a member of the WNT family of proteins that is closely related to WNT5A, is required for cell migration, cell proliferation, or cell differentiation in many cell types. WNT5B signals through the non-canonical β-catenin-independent signaling pathway and often functions as an antagonist of canonical WNT signaling. Although WNT5B has a high amino acid identity with WNT5A and is often assumed to have similar activities, WNT5B often exhibits unique expression patterns and functions. Here, we describe the distinct effects and mechanisms of WNT5B on development, bone, adipose tissue, cardiac tissue, the nervous system, the mammary gland, the lung and hematopoietic cells, compared to WNT5A. We also highlight aberrances in non-canonical WNT5B signaling contributing to diseases such as osteoarthritis, osteoporosis, obesity, type 2 diabetes mellitus, neuropathology, and chronic diseases associated with aging, as well as various cancers.
Collapse
Affiliation(s)
- Sarocha Suthon
- Department of Orthopaedic Surgery and Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Rachel S Perkins
- Department of Orthopaedic Surgery and Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Vitezslav Bryja
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia.,Department of Cytokinetics, Institute of Biophysics, Czech Academy of Sciences, Brno, Czechia
| | - Gustavo A Miranda-Carboni
- Division of Hematology and Oncology, Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States.,Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Susan A Krum
- Department of Orthopaedic Surgery and Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN, United States.,Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, United States
| |
Collapse
|
10
|
Liu Q, Yang H, Zhang M, Zhang J, Lu L, Yu S, Wu Y, Wang M. Initiation and progression of dental-stimulated temporomandibular joints osteoarthritis. Osteoarthritis Cartilage 2021; 29:633-642. [PMID: 33422706 DOI: 10.1016/j.joca.2020.12.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/14/2020] [Accepted: 12/22/2020] [Indexed: 02/02/2023]
Abstract
Temporomandibular joint (TMJ), a site that is often impacted by osteoarthritis (OA), is biomechanically linked with dental occlusion. Tissue responses in TMJ condyle to biomechanical stimulation could be investigated by intervention of the dental occlusion in animals. Unilateral anterior crossbite, an experimental malocclusion, has been demonstrated to induce TMJ-OA lesions, showing primarily as enhanced cartilage calcification and subchondral cortical bone formation at the osteochondral interface, causing the osteochondral interface thickening and stiffening. The changed interface would worsen the local biomechanical environment. At the cartilage side, the matrix degenerates. In the case of insufficient restoration of the matrix, the cells in the deep zone flow into the ones undergoing autophagy, apoptosis, and terminal differentiation while the cells in the superficial zone are promoted to differentiate to supply the loss of the deep zone cells. At the meantime, the bone marrow stromal cells are stimulated to bone formation in the subchondral cortical region which is uncoupled with the sites of the osteoclast-mediated resorption process that is predominantly observed at the subchondral trabecular bone region. Overall, the thickening and stiffening osteochondral interface, due greatly to the enhanced endochondral ossification in deep zone cartilage, should be a central pathological process that links with cartilage decay and subchondral bone remodelling in OA joints. The residual chondrocytes locating in the cartilage superficial zone have the progenitor-like qualities that can proliferate, and also differentiate into the deep zone chondrocytes, thus should be critical in progression and rehabilitation of TMJ-OA.
Collapse
Affiliation(s)
- Q Liu
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - H Yang
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - M Zhang
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - J Zhang
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - L Lu
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - S Yu
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China
| | - Y Wu
- Institute of Orthopedic Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, Shananxi, China
| | - M Wang
- The Key Laboratory of Military Stomatology of State and the National Clinical Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and Clinic of Temporomandibular Joint Disorders and Oral and Maxillofacial Pain, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shananxi, China.
| |
Collapse
|
11
|
Hofstee MI, Muthukrishnan G, Atkins GJ, Riool M, Thompson K, Morgenstern M, Stoddart MJ, Richards RG, Zaat SAJ, Moriarty TF. Current Concepts of Osteomyelitis: From Pathologic Mechanisms to Advanced Research Methods. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:1151-1163. [PMID: 32194053 DOI: 10.1016/j.ajpath.2020.02.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/18/2020] [Accepted: 02/27/2020] [Indexed: 01/18/2023]
Abstract
Osteomyelitis is an inflammation of the bone and bone marrow that is most commonly caused by a Staphylococcus aureus infection. Much of our understanding of the underlying pathophysiology of osteomyelitis, from the perspective of both host and pathogen, has been revised in recent years, with notable discoveries including the role played by osteocytes in the recruitment of immune cells, the invasion and persistence of S. aureus in submicron channels of cortical bone, and the diagnostic role of polymorphonuclear cells in implant-associated osteomyelitis. Advanced in vitro cell culture models, such as ex vivo culture models or organoids, have also been developed over the past decade, and have become widespread in many fields, including infectious diseases. These models better mimic the in vivo environment, allow the use of human cells, and can reduce our reliance on animals in osteomyelitis research. In this review, we provide an overview of the main pathologic concepts in osteomyelitis, with a focus on the new discoveries in recent years. Furthermore, we outline the value of modern in vitro cell culture techniques, with a focus on their current application to infectious diseases and osteomyelitis in particular.
Collapse
Affiliation(s)
- Marloes I Hofstee
- AO Research Institute Davos, Davos, Switzerland; Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, the Netherlands
| | - Gowrishankar Muthukrishnan
- Center for Musculoskeletal Research and Department of Orthopaedics, University of Rochester Medical Center, Rochester, New York
| | - Gerald J Atkins
- Centre for Orthopaedic and Trauma Research, University of Adelaide, Adelaide, South Australia, Australia
| | - Martijn Riool
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, the Netherlands
| | | | - Mario Morgenstern
- Department of Orthopedic Surgery and Traumatology, University Hospital Basel, Basel, Switzerland
| | | | | | - Sebastian A J Zaat
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, the Netherlands
| | | |
Collapse
|
12
|
Li L, Li M, Pang Y, Wang J, Wan Y, Zhu C, Yin Z. Abnormal thyroid hormone receptor signaling in osteoarthritic osteoblasts regulates microangiogenesis in subchondral bone. Life Sci 2019; 239:116975. [PMID: 31654748 DOI: 10.1016/j.lfs.2019.116975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/11/2019] [Accepted: 10/14/2019] [Indexed: 02/07/2023]
Abstract
AIMS Previous study indicated that the increase of local bio-availability of 3'3'5-triiodothyronine (T3) influenced osteoarthritis (OA) initiation. We aimed to investigate the role of thyroid hormone receptors (THRs) signaling in OA osteoblasts. MATERIALS AND METHODS THRs expression in OA was detected by immunohistochemistry, immunofluorescence, RT-qPCR and western blotting. These effects on the expression of angiogenesis-related factors were examined after THRα or THRβ knockdown in OA osteoblasts. Fluorescence in situ hybridization was used to confirm the leading receptor for regulating angiogenesis-related factors. Co-culture model was utilized to observe the MMPs expression in chondrocytes after THRα knockdown in osteoblasts. The in vivo effects were also studied after intra-articular injection with THRα siRNA in OA model mice. Micro-CT and immunohistochemistry were employed to evaluate the changes of subchondral bone. KEY FINDINGS THRs expression and nuclear translocation were upregulated in human OA osteoblasts. Immunohistochemistry showed that angiogenic activities were increased in OA subchondral bone of human and mice. VEGF, HIF-1α and IGF-1, these THR downstream genes were downregulated after THRα knockdown in OA osteoblasts. Fluorescence in situ hybridization further indicated that THRα signaling mainly regulated VEGF expression. Intra-articular injection with THRα siRNA reduced angiogenic activities in OA model mice subchondral bone and ameliorated cartilage degradation. Micro-CT analysis displayed that the aberrant subchondral bone formation in OA was promoted. SIGNIFICANCE The microangiogenesis in subchondral bone may be partly attributed to abnormal THRα signaling in osteoblasts, and local inhibition of the THRα could be a potential target to treat OA.
Collapse
Affiliation(s)
- Lei Li
- Department of Orthopaedics, the first affiliated hospital of Anhui Medical Universtiy, #218 Jixi Road, Hefei, Anhui, China
| | - Meng Li
- Department of Orthopaedics, the first affiliated hospital of University of Science and Technology of China, #17 Lujiang Road, Hefei, Anhui, China
| | - Yiqun Pang
- Department of radiology, the first affiliated hospital of University of Science and Technology of China, #17 Lujiang Road, Hefei, Anhui, China
| | - Jun Wang
- Department of Orthopaedics, the first affiliated hospital of Anhui Medical Universtiy, #218 Jixi Road, Hefei, Anhui, China
| | - Yunpeng Wan
- Department of Orthopaedics, the first affiliated hospital of Anhui Medical Universtiy, #218 Jixi Road, Hefei, Anhui, China
| | - Chen Zhu
- Department of Orthopaedics, the first affiliated hospital of University of Science and Technology of China, #17 Lujiang Road, Hefei, Anhui, China.
| | - Zongsheng Yin
- Department of Orthopaedics, the first affiliated hospital of Anhui Medical Universtiy, #218 Jixi Road, Hefei, Anhui, China.
| |
Collapse
|
13
|
Human osteocyte expression of Nerve Growth Factor: The effect of Pentosan Polysulphate Sodium (PPS) and implications for pain associated with knee osteoarthritis. PLoS One 2019; 14:e0222602. [PMID: 31557169 PMCID: PMC6762051 DOI: 10.1371/journal.pone.0222602] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 09/03/2019] [Indexed: 01/05/2023] Open
Abstract
Pentosan polysulphate sodium (PPS) is a promising therapeutic agent for blocking knee pain in individuals with knee osteoarthritis (KOA). The mode of action of PPS in this context is unknown. We hypothesised that the osteocyte, being the principal cell type in the sub-chondral bone, was capable of expressing the pain mediator Nerve Growth Factor (NGF), and that this may be altered in the presence of PPS. We tested the expression of NGF and the response to PPS in the presence or absence of the proinflammatory cytokine tumour necrosis factor-alpha (TNFα), in human osteocytes. For this we differentiated human primary osteoblasts grown from subchondral bone obtained at primary knee arthroplasty for KOA to an osteocyte-like stage over 28d. We also tested NGF expression in fresh osteocytes obtained by sequential digestion from KOA bone and by immunofluorescence in KOA bone sections. We demonstrate for the first time the production and secretion of NGF/proNGF by this cell type derived from patients with KOA, implicating osteocytes in the pain response in this pathological condition and possibly others. PPS inhibited TNFα-induced levels of proNGF secretion and TNFα induced NGF mRNA expression. Together, this provides evidence that PPS may act to suppress the release of NGF in the subchondral bone to ameliorate pain associated with knee osteoarthritis.
Collapse
|
14
|
Alliston T, Hernandez CJ, Findlay DM, Felson DT, Kennedy OD. Bone marrow lesions in osteoarthritis: What lies beneath. J Orthop Res 2018; 36:1818-1825. [PMID: 29266428 PMCID: PMC8607515 DOI: 10.1002/jor.23844] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/27/2017] [Indexed: 02/04/2023]
Abstract
Osteoarthritis (OA) is the most common joint disease in the United States, affecting more than 30 million people, and is characterized by cartilage degeneration in articulating joints. OA can be viewed as a group of overlapping disorders, which result in functional joint failure. However, the precise cellular and molecular events within which lead to these clinically observable changes are neither well understood nor easily measurable. It is now clear that multiple factors, in multiple joint tissues, contribute to degeneration. Changes in subchondral bone are recognized as a hallmark of OA, but are normally associated with late-stage disease when degeneration is well established. However, early changes such as Bone Marrow Lesions (BMLs) in OA are a relatively recent discovery. BMLs are patterns from magnetic resonance images (MRI) that have been linked with pain and cartilage degeneration. Their potential utility in predicting progression, or as a target for therapy, is not yet fully understood. Here, we will review the current state-of-the-art in this field under three broad headings: (i) BMLs in symptomatic OA: malalignment, joint pain, and disease progression; (ii) biological considerations for bone-cartilage crosstalk in joint disease; and (iii) mechanical factors that may underlie BMLs and drive their communication with other joint tissues. Thus, this review will provide insights on this topic from a clinical, biological, and mechanical perspective. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1818-1825, 2018.
Collapse
Affiliation(s)
- Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, CA, USA
| | - Christopher J Hernandez
- Sibley School of Mechanical and Aerospace Engineering, Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York. Hospital for Special Surgery, New York, New York
| | - David M. Findlay
- Discipline of Orthopaedics and Trauma, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - David T. Felson
- Clinical Epidemiology Research and Training Unit Boston University School of Medicine, Boston, Massachusetts, USA
| | - Oran D. Kennedy
- Department of Anatomy and Tissue Engineering Research Group, Royal College of Surgeons in Ireland, Dublin 2, Ireland,Trinity Centre for Bioengineering, Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
15
|
Tao J, Dong B, Yang LX, Xu KQ, Ma S, Lu J. TGF‑β1 expression in adults with non‑traumatic osteonecrosis of the femoral head. Mol Med Rep 2017; 16:9539-9544. [PMID: 29152655 DOI: 10.3892/mmr.2017.7817] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/01/2017] [Indexed: 11/05/2022] Open
Abstract
Non-traumatic osteonecrosis of the femoral head (NONFH) is a common clinical osteoarthropathy. The present study aimed to investigate the association between transforming growth factor β1 (TGF‑β1) and NONFH. Femoral head specimens were collected from patients with NONFH. Patients with traumatic osteonecrosis served as the control. Hematoxylin and eosin (H&E) staining was used to visualize the bone tissue architecture. Immunohistochemistry and densitometry were performed to quantify TGF‑β1 expression in tissues. Flow cytometry was used to detect cluster of differentiation (CD)3+, CD4+ and CD8+ cells, and the ratio of CD4+ to CD8+ T cells in the peripheral blood. H&E staining revealed osteonecrosis, disintegration of osteocytes with karyopyknosis and karyorrhexis, loss of osteocyte lacunae, aberrantly arranged circumferential lamellae, as well as dissolution of the lamellae and subtle osteogenesis in the experimental group, as opposed to the control group. Immunohistochemistry revealed that the expression of TGF‑β1 was significantly reduced in the experimental group (P<0.01). Further, the NONFH group had a decrease in the CD3+ and CD4+ cell populations (P<0.05 and P<0.01, respectively), an increase in the CD8+ cell population (P<0.05), as well as a reduction in the ratio of CD4+ to CD8+ cells (P<0.01). The present study indicated that TGF‑β1 expression was reduced in NONFH. This was associated with impaired repairing capacity of the femoral head and dysregulated subsets of T‑lymphocytes and possible immune functions.
Collapse
Affiliation(s)
- Jun Tao
- Department of Orthopaedics, Huainan No. 1 People's Hospital, Huainan, Anhui 232007, P.R. China
| | - Bin Dong
- Department of Orthopaedics, Huainan No. 1 People's Hospital, Huainan, Anhui 232007, P.R. China
| | - Li-Xin Yang
- Department of Orthopaedics, Huainan No. 1 People's Hospital, Huainan, Anhui 232007, P.R. China
| | - Ke-Qing Xu
- Department of Orthopaedics, Huainan No. 1 People's Hospital, Huainan, Anhui 232007, P.R. China
| | - Shuai Ma
- Department of Orthopaedics, Huainan No. 1 People's Hospital, Huainan, Anhui 232007, P.R. China
| | - Jun Lu
- Department of Pathogen Biology and Immunology, School of Medicine, Anhui University of Science and Technology, Huainan, Anhui 232001, P.R. China
| |
Collapse
|
16
|
da Silva MR, Linhares D, Vasconcelos DM, Alves CJ, Neves N, Costa G, Lamghari M. Neuroimmune expression in hip osteoarthritis: a systematic review. BMC Musculoskelet Disord 2017; 18:394. [PMID: 28893229 PMCID: PMC5594449 DOI: 10.1186/s12891-017-1755-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/07/2017] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Neuroimmune axis is central in the physiopathology of hip osteoarthritis (OA), but its specific pathways are still unclear. This systematic review aims to assess the nervous and immune system profile of patients with hip osteoarthritis (OA) when compared to healthy controls. METHODS A systematic review followed PRISMA guidelines was conducted. A two-step selection process was completed, and from 609 references 17 were included. The inclusion criteria were: original articles on adult patients with hip OA, with assessment of neuroimmune expression. Articles with other interventions prior to analysis and those without a control group were excluded. RESULTS Thirty-nine relevant neuroimmune markers were identified, with assessments in bone, cartilage, synovial membrane, synovial fluid, whole blood, serum and/or immune cells. GM-CSF, IFN-γ, IL-1α, IL-6, IL-8, IL-1 and TNF-α presented variable expression among tissues studied when compared between hip OA and controls. VEGFs and TGF-ß isoforms showed similar tendencies among tissues and studies. On nervous expression, CGRP, Tuj-1 and SP were increased in synovial membrane. Overall, patients with hip OA presented a higher number of overexpressed markers. CONCLUSIONS For the first time a systematic review on neuroimmune expression in patients with hip OA found an upregulation of neuroimmune markers, with deregulated balance between pro and anti-inflammatory cytokines. However, no clear systematic pattern was found, and few information is available on nervous expression. This highlights the importance of future research with clear methodologies to guide the management of these patients.
Collapse
Affiliation(s)
- Manuel Ribeiro da Silva
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal. .,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal. .,Serviço de Ortopedia e Traumatologia, Centro Hospitalar São João, Porto, Portugal. .,Faculdade de Medicina, Universidade do Porto, Porto, Portugal. .,Orthopedic Department, CHSJ - Centro Hospitalar de São João, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
| | - Daniela Linhares
- Serviço de Ortopedia e Traumatologia, Centro Hospitalar São João, Porto, Portugal.,Orthopedic Department, CHSJ - Centro Hospitalar de São João, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.,MEDCIDS - Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Daniel Marques Vasconcelos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Cecilia Juliana Alves
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Nuno Neves
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,Serviço de Ortopedia e Traumatologia, Centro Hospitalar São João, Porto, Portugal.,Faculdade de Medicina, Universidade do Porto, Porto, Portugal.,Orthopedic Department, CHSJ - Centro Hospitalar de São João, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Gilberto Costa
- Serviço de Ortopedia e Traumatologia, Centro Hospitalar São João, Porto, Portugal.,Faculdade de Medicina, Universidade do Porto, Porto, Portugal.,Orthopedic Department, CHSJ - Centro Hospitalar de São João, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Meriem Lamghari
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| |
Collapse
|
17
|
Targeting subchondral bone mesenchymal stem cell activities for intrinsic joint repair in osteoarthritis. Future Sci OA 2017; 3:FSO228. [PMID: 29134116 PMCID: PMC5674229 DOI: 10.4155/fsoa-2017-0055] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/02/2017] [Indexed: 12/14/2022] Open
Abstract
Osteoarthritis (OA) is a common age-related disease with complex pathophysiology. It is characterized by wide-ranging tissue damage and ultimate biomechanical failure of the whole joint. However, signs of tissue adaptation and attempted repair responses are evident in OA-affected osteochondral tissues. Highlighted in this review article is the role of bone-resident mesenchymal stem cells (MSCs) in these bone remodeling responses, and a proposal that targeting MSC activities in OA subchondral bone could represent a novel approach for intrinsic joint regeneration in OA. The development of these therapies will require better understanding of MSC proliferation, migration and differentiation patterns in relation to OA tissue damage and further clarification of the molecular signaling events in these MSCs during disease progression. Osteoarthritis (OA) is a joint disorder, in which the cartilage, the underlying bone and other joint tissues are affected. Recent evidence demonstrating attempted repair responses in these OA tissues challenges the traditional view of OA as a degenerative disorder. Signs of tissue regeneration are particularly evident in the bone located directly underneath the damaged cartilage, where increased stem cell activity has been observed. Targeting these stem cells could represent a novel approach for intrinsic joint regeneration in OA. To progress with developing these novel therapies, a better understanding of stem cell function in normal and OA joint tissues is needed.
Collapse
|
18
|
Maruotti N, Corrado A, Cantatore FP. Osteoblast role in osteoarthritis pathogenesis. J Cell Physiol 2017; 232:2957-2963. [PMID: 28425564 PMCID: PMC5575507 DOI: 10.1002/jcp.25969] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/19/2017] [Indexed: 01/13/2023]
Abstract
Even if osteoarthritis pathogenesis is still poorly understood, numerous evidences suggest that osteoblasts dysregulation plays a key role in osteoarthritis pathogenesis. An abnormal expression of OPG and RANKL has been described in osteoarthritis osteoblasts, which is responsible for abnormal bone remodeling and decreased mineralization. Alterations in genes expression are involved in dysregulation of osteoblast function, bone remodeling, and mineralization, leading to osteoarthritis development. Moreover, osteoblasts produce numerous transcription factors, growth factors, and other proteic molecules which are involved in osteoarthritis pathogenesis.
Collapse
Affiliation(s)
- Nicola Maruotti
- Rheumatology Clinic, Department of Medical and Surgical Sciences, University of Foggia Medical School, Foggia, Italy
| | - Addolorata Corrado
- Rheumatology Clinic, Department of Medical and Surgical Sciences, University of Foggia Medical School, Foggia, Italy
| | - Francesco P Cantatore
- Rheumatology Clinic, Department of Medical and Surgical Sciences, University of Foggia Medical School, Foggia, Italy
| |
Collapse
|
19
|
|
20
|
Bone-cartilage crosstalk: a conversation for understanding osteoarthritis. Bone Res 2016; 4:16028. [PMID: 27672480 PMCID: PMC5028726 DOI: 10.1038/boneres.2016.28] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 07/27/2016] [Indexed: 01/06/2023] Open
Abstract
Although cartilage degradation is the characteristic feature of osteoarthritis (OA), it is now recognized that the whole joint is involved in the progression of OA. In particular, the interaction (crosstalk) between cartilage and subchondral bone is thought to be a central feature of this process. The interface between articular cartilage and bone of articulating long bones is a unique zone, which comprises articular cartilage, below which is the calcified cartilage sitting on and intercalated into the subchondral bone plate. Below the subchondral plate is the trabecular bone at the end of the respective long bones. In OA, there are well-described progressive destructive changes in the articular cartilage, which parallel characteristic changes in the underlying bone. This review examines the evidence that biochemical and biomechanical signaling between these tissue compartments is important in OA disease progression and asks whether such signaling might provide possibilities for therapeutic intervention to halt or slow disease development.
Collapse
|
21
|
Klose-Jensen R, Hartlev LB, Boel LWT, Laursen MB, Stengaard-Pedersen K, Keller KK, Hauge EM. Subchondral bone turnover, but not bone volume, is increased in early stage osteoarthritic lesions in the human hip joint. Osteoarthritis Cartilage 2015; 23:2167-2173. [PMID: 26074361 DOI: 10.1016/j.joca.2015.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/07/2015] [Accepted: 06/02/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The pathogenesis of osteoarthritis (OA) is not fully understood, but bone changes are suggested to be important. Bone turnover and bone volume (BV) in human hip OA were investigated in relation to the overlying cartilage degeneration using design-based stereological estimators. MATERIALS AND METHODS Femoral heads were obtained from 25 end-stage OA patients and 24 controls (CTL). Design-based stereological methods were used for sampling and quantification to obtain absolute estimates of volume and surface in the central trabecular and the subarticular bone region. The subarticular bone was further subdivided into regions according to the OARSI-score of the overlying articular cartilage in which erosion and osteoid surfaces were estimated. RESULTS In the subarticular region, bone volume (BV/TV) was 15.0% higher in OA patients compared to CTL; The fraction of erosive (ES/BS) and osteoid surfaces (OS/BS) were 56.2% and 72.8% higher in OA compared to CTL. In subarticular regions with none to mild cartilage degeneration (OARSI grade 0-2), ES/BS and OS/BS were 48.6% and 59.9% higher in OA compared to CTL, whereas BV/TV did not differ between OA and CTL. CONCLUSION In human end-stage hip OA, BV and bone turnover correlate with the degree of local cartilage degeneration. Subarticular bone sclerosis was only present in regions corresponding to end-stage OA. However, in regions with only none to mild cartilage degeneration the underlying bone had significantly higher turnover in OA patients compared to the control group, suggesting that high bone turnover may contribute to the early pathogenesis of OA.
Collapse
Affiliation(s)
- R Klose-Jensen
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | - L B Hartlev
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | - L W T Boel
- Institute of Forensic Medicine, Aarhus University, Aarhus, Denmark
| | - M B Laursen
- Hip and Knee Arthroplasty, Northern Orthopaedic Division, Aalborg University Hospital, Aalborg, Denmark
| | | | - K K Keller
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | - E-M Hauge
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark.
| |
Collapse
|
22
|
Yang D, Turner AG, Wijenayaka AR, Anderson PH, Morris HA, Atkins GJ. 1,25-Dihydroxyvitamin D3 and extracellular calcium promote mineral deposition via NPP1 activity in a mature osteoblast cell line MLO-A5. Mol Cell Endocrinol 2015; 412:140-7. [PMID: 26054750 DOI: 10.1016/j.mce.2015.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 06/01/2015] [Accepted: 06/03/2015] [Indexed: 10/23/2022]
Abstract
While vitamin D supplementation is common, the anabolic mechanisms that improve bone status are poorly understood. Under standard mineralising conditions including media ionised calcium of 1.1 mM, 1,25-dihydroxyvitamin D3 (1,25D) enhanced differentiation and mineral deposition by the mature osteoblast/pre-osteocyte cell line, MLO-A5. This effect was markedly increased with a higher ionised calcium level (1.5 mM). Gene expression analyses revealed that 1,25D-induced mineral deposition was associated with induction of Enpp1 mRNA, coding for nucleotide pyrophosphatase phosphodiesterase 1 (NPP1) and NPP1 protein levels. Since MLO-A5 cells express abundant alkaline phosphatase that was not further modified by 1,25D treatment or exposure to increased calcium, this finding suggested that the NPP1 production of pyrophosphate (PPi) may provide alkaline phosphatase with substrate for the generation of inorganic phosphate (Pi). Consistent with this, co-treatment with Enpp1 siRNA or a NPP1 inhibitor, PPADS, abrogated 1,25D-induced mineral deposition. These data demonstrate that 1,25D stimulates osteoblast differentiation and mineral deposition, and interacts with the extracellular calcium concentration. 1,25D regulates Enpp1 expression, which presumably, in the context of adequate tissue non-specific alkaline phosphatase activity, provides Pi to stimulate mineralisation. Our findings suggest a mechanism by which vitamin D with adequate dietary calcium can improve bone mineral status.
Collapse
Affiliation(s)
- Dongqing Yang
- Bone Cell Biology Group, Centre for Orthopaedic and Trauma Research, University of Adelaide, Adelaide, SA 5005, Australia; Discipline of Medicine, University of Adelaide, Adelaide, SA 5005, Australia
| | - Andrew G Turner
- Discipline of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Musculoskeletal Biology Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Asiri R Wijenayaka
- Bone Cell Biology Group, Centre for Orthopaedic and Trauma Research, University of Adelaide, Adelaide, SA 5005, Australia
| | - Paul H Anderson
- Discipline of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Musculoskeletal Biology Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Howard A Morris
- Discipline of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; Musculoskeletal Biology Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia; Endocrine Bone Research, Chemical Pathology, SA Pathology, Adelaide, SA 5000, Australia
| | - Gerald J Atkins
- Bone Cell Biology Group, Centre for Orthopaedic and Trauma Research, University of Adelaide, Adelaide, SA 5005, Australia.
| |
Collapse
|
23
|
Abed E, Bouvard B, Martineau X, Jouzeau JY, Reboul P, Lajeunesse D. Elevated hepatocyte growth factor levels in osteoarthritis osteoblasts contribute to their altered response to bone morphogenetic protein-2 and reduced mineralization capacity. Bone 2015; 75:111-9. [PMID: 25667190 DOI: 10.1016/j.bone.2015.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/24/2015] [Accepted: 02/01/2015] [Indexed: 10/24/2022]
Abstract
PURPOSE Clinical and in vitro studies suggest that subchondral bone sclerosis due to abnormal osteoblasts is involved in the progression of osteoarthritis (OA). Human osteoblasts isolated from sclerotic subchondral OA bone tissue show an altered phenotype, a decreased canonical Wnt/ß-catenin pathway, and a reduced mineralization in vitro as well as in vivo. These alterations were linked with an abnormal response to BMP-2. OA osteoblasts release factors such as the hepatocyte growth factor (HGF) that contribute to cartilage loss whereas chondrocytes do not express HGF. HGF can stimulate BMP-2 expression in human osteoblasts, however, the role of HGF and its effect in OA osteoblasts remains unknown. Here we investigated whether elevated endogenous HGF levels in OA osteoblasts are responsible for their altered response to BMP-2. METHODS We prepared primary human subchondral osteoblasts using the sclerotic medial portion of the tibial plateaus of OA patients undergoing total knee arthroplasty, or from tibial plateaus of normal individuals obtained at autopsy. The expression of HGF was evaluated by qRT-PCR and the protein production by western blot analysis. HGF expression was reduced with siRNA technique whereas its activity was inhibited using the selective inhibitor PHA665752. Alkaline phosphatase activity (ALPase) and osteocalcin release were measured by substrate hydrolysis and EIA respectively. Canonical Wnt/β-catenin signaling (cWnt) was evaluated both by target gene expression using the TOPflash TCF/lef luciferase reporter assay and western blot analysis of β-catenin levels in response to Wnt3a stimulation. Mineralization in response to BMP-2 was evaluated by alizarin red staining. RESULTS The expression of HGF was increased in OA osteoblasts compared to normal osteoblasts and was maintained during their in vitro differentiation. OA osteoblasts released more HGF than normal osteoblasts as assessed by western blot analysis. HGF stimulated the expression of TGF-β1. BMP-2 dose-dependently (1 to 100 ng/ml) stimulated both ALPase and osteocalcin in normal osteoblasts whereas, it inhibited them in OA osteoblasts. HGF-siRNA treatments reversed this response in OA osteoblasts and restored the BMP-2 response. cWnt is reduced in OA osteoblasts compared to normal, and HGF-siRNA treatments increased cWnt in OA osteoblasts almost to normal. Smad1/5/8 phosphorylation in response to BMP-2, which is reduced in OA osteoblasts, was corrected when these cells were treated with PHA665752. The BMP-2-dependent mineralization of OA osteoblasts, which is also reduced compared to normal, was only partially restored by PHA665752 treatment whereas 28 days treatment with HGF reduced the mineralization of normal osteoblasts. CONCLUSION OA osteoblasts expressed more HGF than normal osteoblasts. Increased endogenous HGF production in OA osteoblasts stimulated the expression of TGF-β1 and reduced their response to BMP-2. Inhibiting HGF expression or HGF signaling restored the response to BMP-2 and Smad1/5/8 signaling. In addition, decreased HGF signaling partly corrects the abnormal mineralization of OA osteoblasts while increased HGF prevents the normal mineralization of normal osteoblasts. In summary, we hypothesize that sustained elevated HGF levels in OA osteoblasts drive their abnormal phenotype and is implicated in OA pathophysiology.
Collapse
Affiliation(s)
- E Abed
- Unité de recherche en Arthrose, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - B Bouvard
- UMR7365 IMoPA, Université de Lorraine/CNRS, Vandœuvre lès Nancy, 54505, France; Service de Rhumatologie, Centre Hospitalier Universitaire (CHU), Angers 49933, France
| | - X Martineau
- Unité de recherche en Arthrose, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - J-Y Jouzeau
- UMR7365 IMoPA, Université de Lorraine/CNRS, Vandœuvre lès Nancy, 54505, France; Service de Pharmacologie Clinique et de Toxicologie, Centre Hospitalier Universitaire (CHU), Nancy 54023, France
| | - P Reboul
- UMR7365 IMoPA, Université de Lorraine/CNRS, Vandœuvre lès Nancy, 54505, France
| | - D Lajeunesse
- Unité de recherche en Arthrose, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.
| |
Collapse
|
24
|
Prideaux M, Wijenayaka AR, Kumarasinghe DD, Ormsby RT, Evdokiou A, Findlay DM, Atkins GJ. SaOS2 Osteosarcoma cells as an in vitro model for studying the transition of human osteoblasts to osteocytes. Calcif Tissue Int 2014; 95:183-93. [PMID: 24916279 DOI: 10.1007/s00223-014-9879-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/21/2014] [Indexed: 12/18/2022]
Abstract
The central importance of osteocytes in regulating bone homeostasis is becoming increasingly apparent. However, the study of these cells has been restricted by the relative paucity of cell line models, especially those of human origin. Therefore, we investigated the extent to which SaOS2 human osteosarcoma cells can differentiate into osteocyte-like cells. During culture under the appropriate mineralising conditions, SaOS2 cells reproducibly synthesised a bone-like mineralised matrix and temporally expressed the mature osteocyte marker genes SOST, DMP1, PHEX and MEPE and down-regulated expression of RUNX2 and COL1A1. SaOS2 cells cultured in 3D collagen gels acquired a dendritic morphology, characteristic of osteocytes, with multiple interconnecting cell processes. These findings suggest that SaOS2 cells have the capacity to differentiate into mature osteocyte-like cells under mineralising conditions. PTH treatment of SaOS2 cells resulted in strong down-regulation of SOST mRNA expression at all time points tested. Interestingly, PTH treatment resulted in the up-regulation of RANKL mRNA expression only at earlier stages of differentiation. These findings suggest that the response to PTH is dependent on the differentiation stage of the osteoblast/osteocyte. Together, our results demonstrate that SaOS2 cells can be used as a human model to investigate responses to osteotropic stimuli throughout differentiation to a mature osteocyte-like stage.
Collapse
Affiliation(s)
- Matthew Prideaux
- Bone Cell Biology Group, Centre for Orthopaedic and Trauma Research, The University of Adelaide, North Terrace, Adelaide, SA, 5005, Australia
| | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
There is now general agreement that osteoarthritis (OA) involves all structures in the affected joint, culminating in the degradation of the articular cartilage. It is appropriate to focus particularly on the subchondral bone because characteristic changes occur in this tissue with disease progression, either in parallel, or contributing to, the loss of cartilage volume and quality. Changes in both the articular cartilage and the subchondral bone are mediated by the cells in these two compartments, chondrocytes and cells of the osteoblast lineage, respectively, whose primary roles are to maintain the integrity and function of these tissues. In addition, altered rates of bone remodeling across the disease process are due to increased or decreased osteoclastic bone resorption. In the altered mechanical and biochemical environment of a progressively diseased joint, the cells function differently and show a different profile of gene expression, suggesting direct effects of these external influences. There is also ex vivo and in vitro evidence of chemical crosstalk between the cells in cartilage and subchondral bone, suggesting an interdependence of events in the two compartments and therefore indirect effects of, for example, altered loading of the joint. It is ultimately these cellular changes that explain the altered morphology of the cartilage and subchondral bone. With respect to crosstalk between the cells in cartilage and bone, there is evidence that small molecules can transit between these tissues. For larger molecules, such as inflammatory mediators, this is an intriguing possibility but remains to be demonstrated. The cellular changes during the progression of OA almost certainly need to be considered in a temporal and spatial manner, since it is important when and where observations are made in either human disease or animal models of OA. Until recently, comparisons have been made with the assumption, for example, that the subchondral bone is behaviorally uniform, but this is not the case in OA, where regional differences of the bone are evident using magnetic resonance imaging (MRI). Nevertheless, an appreciation of the altered cell function during the progression of OA will identify new disease modifying targets. If, indeed, the cartilage and subchondral bone behave as an interconnected functional unit, normalization of cell behavior in one compartment may have benefits in both tissues.
Collapse
Affiliation(s)
- David M Findlay
- Centre for Orthopaedic and Trauma Research, The University of Adelaide, Royal Adelaide Hospital, Level 4 Bice Building, Adelaide, South Australia, 5000, Australia,
| | | |
Collapse
|
26
|
Functional annotation of rheumatoid arthritis and osteoarthritis associated genes by integrative genome-wide gene expression profiling analysis. PLoS One 2014; 9:e85784. [PMID: 24551036 PMCID: PMC3925090 DOI: 10.1371/journal.pone.0085784] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 12/02/2013] [Indexed: 12/20/2022] Open
Abstract
Background Rheumatoid arthritis (RA) and osteoarthritis (OA) are two major types of joint diseases that share multiple common symptoms. However, their pathological mechanism remains largely unknown. The aim of our study is to identify RA and OA related-genes and gain an insight into the underlying genetic basis of these diseases. Methods We collected 11 whole genome-wide expression profiling datasets from RA and OA cohorts and performed a meta-analysis to comprehensively investigate their expression signatures. This method can avoid some pitfalls of single dataset analyses. Results and Conclusion We found that several biological pathways (i.e., the immunity, inflammation and apoptosis related pathways) are commonly involved in the development of both RA and OA. Whereas several other pathways (i.e., vasopressin-related pathway, regulation of autophagy, endocytosis, calcium transport and endoplasmic reticulum stress related pathways) present significant difference between RA and OA. This study provides novel insights into the molecular mechanisms underlying this disease, thereby aiding the diagnosis and treatment of the disease.
Collapse
|
27
|
Karsdal MA, Bay-Jensen AC, Lories RJ, Abramson S, Spector T, Pastoureau P, Christiansen C, Attur M, Henriksen K, Goldring SR, Kraus V. The coupling of bone and cartilage turnover in osteoarthritis: opportunities for bone antiresorptives and anabolics as potential treatments? Ann Rheum Dis 2013; 73:336-48. [PMID: 24285494 DOI: 10.1136/annrheumdis-2013-204111] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Osteoarthritis (OA) is the most common form of arthritic disease, and a major cause of disability and impaired quality of life in the elderly. OA is a complex disease of the entire joint, affecting bone, cartilage and synovium that thereby presents multiple targets for treatment. This manuscript will summarise emerging observations from cell biology, preclinical and preliminary clinical trials that elucidate interactions between the bone and cartilage components in particular. Bone and cartilage health are tightly associated. Ample evidence has been found for bone changes during progression of OA including, but not limited to, increased turnover in the subchondral bone, undermineralisation of the trabecular structure, osteophyte formation, bone marrow lesions and sclerosis of the subchondral plate. Meanwhile, a range of investigations has shown positive effects on cartilage health when bone resorption is suppressed, or deterioration of the cartilage when resorption is increased. Known bone therapies, namely oestrogens, selective oestrogen receptor modifiers (SERMs), bisphosphonates, strontium ranelate, calcitonin and parathyroid hormone, might prove useful for treating two critical tissue components of the OA joint, the bone and the cartilage. An optimal treatment for OA likely targets at least these two tissue components. The patient subgroups for whom these therapies are most appropriate have yet to be fully defined but would likely include, at a minimum, those with high bone turnover.
Collapse
|