1
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Louka P, Orriss IR, Pitsillides AA. Stable Sulforaphane Targets the Early Stages of Osteoclast Formation to Engender a Lasting Functional Blockade of Osteoclastogenesis. Cells 2024; 13:165. [PMID: 38247857 PMCID: PMC10814088 DOI: 10.3390/cells13020165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
Sulforaphane, the native but unstable form of SFX-01, is an antioxidant that activates the NRF2 and inhibits the NF-KB pathways to achieve its actions. Resolving the mechanism(s) by which SFX-01 serves to control the various osteoclastogenic stages may expose pathways that could be explored for therapeutic use. Here we seek to identify the stage of osteoclastogenesis targeted by SFX-01 and explore whether, like SFN, it exerts its actions via the NRF2 and NF-KB pathways. Osteoclasts generated from the bone marrow (BM) of mice were cultured with SFX-01 at different timepoints to examine each phase of osteoclastogenesis separately. This showed that SFX-01 exerted actions throughout the process of osteoclastogenesis, but had its largest effects in the early osteoclast precursor differentiation stage. Thus, treatment with SFX-01 for the duration of culture, for the initial 3 days differentiation or for as little as the first 24 h was sufficient for effective inhibition. This aligned with data suggesting that SFX-01 reduced DC-STAMP levels, osteoclast nuclear number and modified cytoskeletal architecture. Pharmacological regulation of the NRF2 pathways, via selective inhibitors/activators, supported the anti-osteoclastogenic roles of an SFX-01-mediated by NRF2 activation, as well as the need for tight NF-KB pathway regulation in osteoclast formation/function.
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Affiliation(s)
| | | | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK; (P.L.); (I.R.O.)
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2
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Crane-Smith Z, De Castro SCP, Nikolopoulou E, Wolujewicz P, Smedley D, Lei Y, Mather E, Santos C, Hopkinson M, Pitsillides AA, Finnell RH, Ross ME, Copp AJ, Greene NDE. A non-coding insertional mutation of Grhl2 causes gene over-expression and multiple structural anomalies including cleft palate, spina bifida and encephalocele. Hum Mol Genet 2023; 32:2681-2692. [PMID: 37364051 PMCID: PMC10460492 DOI: 10.1093/hmg/ddad094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/19/2023] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
Orofacial clefts, including cleft lip and palate (CL/P) and neural tube defects (NTDs) are among the most common congenital anomalies, but knowledge of the genetic basis of these conditions remains incomplete. The extent to which genetic risk factors are shared between CL/P, NTDs and related anomalies is also unclear. While identification of causative genes has largely focused on coding and loss of function mutations, it is hypothesized that regulatory mutations account for a portion of the unidentified heritability. We found that excess expression of Grainyhead-like 2 (Grhl2) causes not only spinal NTDs in Axial defects (Axd) mice but also multiple additional defects affecting the cranial region. These include orofacial clefts comprising midline cleft lip and palate and abnormalities of the craniofacial bones and frontal and/or basal encephalocele, in which brain tissue herniates through the cranium or into the nasal cavity. To investigate the causative mutation in the Grhl2Axd strain, whole genome sequencing identified an approximately 4 kb LTR retrotransposon insertion that disrupts the non-coding regulatory region, lying approximately 300 base pairs upstream of the 5' UTR. This insertion also lies within a predicted long non-coding RNA, oriented on the reverse strand, which like Grhl2 is over-expressed in Axd (Grhl2Axd) homozygous mutant embryos. Initial analysis of the GRHL2 upstream region in individuals with NTDs or cleft palate revealed rare or novel variants in a small number of cases. We hypothesize that mutations affecting the regulation of GRHL2 may contribute to craniofacial anomalies and NTDs in humans.
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Affiliation(s)
- Zoe Crane-Smith
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sandra C P De Castro
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Evanthia Nikolopoulou
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Paul Wolujewicz
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
| | - Damian Smedley
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Yunping Lei
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Emma Mather
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Chloe Santos
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Mark Hopkinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK
| | | | - Richard H Finnell
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - M Elisabeth Ross
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
| | - Andrew J Copp
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Nicholas D E Greene
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
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3
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Hopkinson M, Jones G, Evans L, Gohin S, Magnusdottir R, Salmon P, Chenu C, Meeson R, Javaheri B, Pitsillides AA. A new method for segmentation and analysis of bone callus in rodent fracture models using micro-CT. J Orthop Res 2023; 41:1717-1728. [PMID: 36582023 PMCID: PMC10947128 DOI: 10.1002/jor.25507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 10/18/2022] [Accepted: 12/21/2022] [Indexed: 12/31/2022]
Abstract
Fracture burden has created a need to better understand bone repair processes under different pathophysiological states. Evaluation of structural and material properties of the mineralized callus, which is integral to restoring biomechanical stability is, therefore, vital. Microcomputed tomography (micro-CT) can facilitate noninvasive imaging of fracture repair, however, current methods for callus segmentation are only semiautomated, restricted to defined regions, time/labor intensive, and prone to user variation. Herein, we share a new automatic method for segmenting callus in micro-CT tomograms that will allow for objective, quantitative analysis of the bone fracture microarchitecture. Fractured and nonfractured mouse femurs were scanned and processed by both manual and automated segmentation of fracture callus from cortical bone after which microarchitectural parameters were analyzed. All segmentation and analysis steps were performed using CTAn (Bruker) with automatic segmentation performed using the software's image-processing plugins. Results showed automatic segmentation reliably and consistently segmented callus from cortical bone, demonstrating good agreement with manual methods with low bias: tissue volume (TV): -0.320 mm3 , bone volume (BV): 0.0358 mm3 , and bone volume/tissue volume (BV/TV): -3.52%, and was faster and eliminated user-bias and variation. Method scalability and translatability across rodent models were verified in scans of fractured rat femora showing good agreement with manual methods with low bias: TV: -3.654 mm3 , BV: 0.830 mm3 , and BV/TV: 7.81%. Together, these data validate a new automated method for segmentation of callus and cortical bone in micro-CT tomograms that we share as a fast, reliable, and less user-dependent tool for application to study bone callus in fracture, and potentially elsewhere.
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Affiliation(s)
- Mark Hopkinson
- Comparative Biological SciencesRoyal Veterinary CollegeLondonUK
| | - Gareth Jones
- Clinical Science and ServicesRoyal Veterinary CollegeLondonUK
| | - Lucinda Evans
- Comparative Biological SciencesRoyal Veterinary CollegeLondonUK
| | - Stephanie Gohin
- Comparative Biological SciencesRoyal Veterinary CollegeLondonUK
| | | | | | - Chantal Chenu
- Comparative Biological SciencesRoyal Veterinary CollegeLondonUK
| | - Richard Meeson
- Clinical Science and ServicesRoyal Veterinary CollegeLondonUK
- Division of SurgeryUniversity College LondonLondonUK
| | - Behzad Javaheri
- Comparative Biological SciencesRoyal Veterinary CollegeLondonUK
- Present address:
School of Mathematics, Computer Science and EngineeringCity University of LondonLondonUK
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4
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Zhu M, Metzen F, Hopkinson M, Betz J, Heilig J, Sodhi J, Imhof T, Niehoff A, Birk DE, Izu Y, Krüger M, Pitsillides AA, Altmüller J, van Osch GJ, Straub V, Schreiber G, Paulsson M, Koch M, Brachvogel B. Ablation of collagen XII disturbs joint extracellular matrix organization and causes patellar subluxation. iScience 2023; 26:107225. [PMID: 37485359 PMCID: PMC10362267 DOI: 10.1016/j.isci.2023.107225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 05/05/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023] Open
Abstract
Collagen XII, belonging to the fibril-associated collagens, is a homotrimeric secreted extracellular matrix (ECM) protein encoded by the COL12A1 gene. Mutations in the human COL12A1 gene cause an Ehlers-Danlos/myopathy overlap syndrome leading to skeletal abnormalities and muscle weakness. Here, we studied the role of collagen XII in joint pathophysiology by analyzing collagen XII deficient mice and human patients. We found that collagen XII is widely expressed across multiple connective tissue of the developing joint. Lack of collagen XII in mice destabilizes tendons and the femoral trochlear groove to induce patellar subluxation in the patellofemoral joint. These changes are associated with an ECM damage response in tendon and secondary quadriceps muscle degeneration. Moreover, patellar subluxation was also identified as a clinical feature of human patients with collagen XII deficiency. The results provide an explanation for joint hyperlaxity in mice and human patients with collagen XII deficiency.
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Affiliation(s)
- Mengjie Zhu
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Fabian Metzen
- Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Mark Hopkinson
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, UK
| | - Janina Betz
- Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Juliane Heilig
- Institute of Biomechanics & Orthopaedics, German Sport University Cologne, Cologne, Germany
- Center for Musculoskeletal Biomechanics (CCMB), Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Jassi Sodhi
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, UK
| | - Thomas Imhof
- Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Anja Niehoff
- Institute of Biomechanics & Orthopaedics, German Sport University Cologne, Cologne, Germany
- Center for Musculoskeletal Biomechanics (CCMB), Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - David E. Birk
- College of Medicine, University of South Florida, Morsani, Tampa, FL, USA
| | - Yayoi Izu
- Department of Veterinary Medicine, Okayama University of Science, Ehime, Japan
| | - Marcus Krüger
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, UK
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Berlin Institute of Health at Charité, Core Facility Genomics, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Gerjo J.V.M. van Osch
- Department of Orthopaedics and Sports Medicine, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
- Department of Otorhinolaryngology, Erasmus MC, University Medical Center, CN Rotterdam, the Netherlands
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle, UK
| | | | - Mats Paulsson
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Manuel Koch
- Institute for Dental Research and Oral Musculoskeletal Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Bent Brachvogel
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Biochemistry, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
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5
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Hansen RT, Chenu C, Sofat N, Pitsillides AA. Bone marrow lesions: plugging the holes in our knowledge using animal models. Nat Rev Rheumatol 2023; 19:429-445. [PMID: 37225964 DOI: 10.1038/s41584-023-00971-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2023] [Indexed: 05/26/2023]
Abstract
Bone marrow lesions (BMLs), which are early signs of osteoarthritis (OA) that are associated with the presence, onset and severity of pain, represent an emerging imaging biomarker and clinical target. Little is known, however, regarding their early spatial and temporal development, structural relationships or aetiopathogenesis, because of the sparsity of human early OA imaging and paucity of relevant tissue samples. The use of animal models is a logical approach to fill the gaps in our knowledge, and it can be informed by appraising models in which BMLs and closely related subchondral cysts have already been reported, including in spontaneous OA and pain models. The utility of these models in OA research, their relevance to clinical BMLs and practical considerations for their optimal deployment can also inform medical and veterinary clinicians and researchers alike.
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Affiliation(s)
- Rebecca T Hansen
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Chantal Chenu
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Nidhi Sofat
- Institute for Infection and Immunity, St George's, University of London, London, UK
- Department of Rheumatology, St George's, University Hospitals NHS Foundation Trust, London, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK.
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6
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Stokes T, Cen HH, Kapranov P, Gallagher IJ, Pitsillides AA, Volmar C, Kraus WE, Johnson JD, Phillips SM, Wahlestedt C, Timmons JA. Transcriptomics for Clinical and Experimental Biology Research: Hang on a Seq. Adv Genet (Hoboken) 2023; 4:2200024. [PMID: 37288167 PMCID: PMC10242409 DOI: 10.1002/ggn2.202200024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Indexed: 06/09/2023]
Abstract
Sequencing the human genome empowers translational medicine, facilitating transcriptome-wide molecular diagnosis, pathway biology, and drug repositioning. Initially, microarrays are used to study the bulk transcriptome; but now short-read RNA sequencing (RNA-seq) predominates. Positioned as a superior technology, that makes the discovery of novel transcripts routine, most RNA-seq analyses are in fact modeled on the known transcriptome. Limitations of the RNA-seq methodology have emerged, while the design of, and the analysis strategies applied to, arrays have matured. An equitable comparison between these technologies is provided, highlighting advantages that modern arrays hold over RNA-seq. Array protocols more accurately quantify constitutively expressed protein coding genes across tissue replicates, and are more reliable for studying lower expressed genes. Arrays reveal long noncoding RNAs (lncRNA) are neither sparsely nor lower expressed than protein coding genes. Heterogeneous coverage of constitutively expressed genes observed with RNA-seq, undermines the validity and reproducibility of pathway analyses. The factors driving these observations, many of which are relevant to long-read or single-cell sequencing are discussed. As proposed herein, a reappreciation of bulk transcriptomic methods is required, including wider use of the modern high-density array data-to urgently revise existing anatomical RNA reference atlases and assist with more accurate study of lncRNAs.
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Affiliation(s)
- Tanner Stokes
- Faculty of ScienceMcMaster UniversityHamiltonL8S 4L8Canada
| | - Haoning Howard Cen
- Life Sciences InstituteUniversity of British ColumbiaVancouverV6T 1Z3Canada
| | | | - Iain J Gallagher
- School of Applied SciencesEdinburgh Napier UniversityEdinburghEH11 4BNUK
| | | | | | | | - James D. Johnson
- Life Sciences InstituteUniversity of British ColumbiaVancouverV6T 1Z3Canada
| | | | | | - James A. Timmons
- Miller School of MedicineUniversity of MiamiMiamiFL33136USA
- William Harvey Research InstituteQueen Mary University LondonLondonEC1M 6BQUK
- Augur Precision Medicine LTDStirlingFK9 5NFUK
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7
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Herbst EC, Evans LAE, Felder AA, Javaheri B, Pitsillides AA. 3D profiling of mouse epiphyses across ages reveals new potential imaging biomarkers of early spontaneous osteoarthritis. J Anat 2023; 242:1037-1050. [PMID: 36772893 PMCID: PMC10184544 DOI: 10.1111/joa.13834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/24/2022] [Accepted: 01/16/2023] [Indexed: 02/12/2023] Open
Abstract
Worldwide research groups and funding bodies have highlighted the need for imaging biomarkers to predict osteoarthritis (OA) progression and treatment effectiveness. Changes in trabecular architecture, which can be detected with non-destructive high-resolution CT imaging, may reveal OA progression before apparent articular surface damage. Here, we analysed the tibial epiphyses of STR/Ort (OA-prone) and CBA (healthy, parental control) mice at different ages to characterise the effects of mouse age and strain on multiple bony parameters. We isolated epiphyseal components using a semi-automated method, and measured the total epiphyseal volume; cortical bone, trabecular bone and marrow space volumes; mean trabecular and cortical bone thicknesses; trabecular volume relative to cortical volume; trabecular volume relative to epiphyseal interior (trabecular BV/TV); and the trabecular degree of anisotropy. Using two-way ANOVA (significance level ≤0.05), we confirmed that all of these parameters change significantly with age, and that the two strains were significantly different in cortical and trabecular bone volumes, and trabecular degree of anisotropy. STR/Ort mice had higher cortical and trabecular volumes and a lower degree of anisotropy. As the two mouse strains reflect markedly divergent OA predispositions, these parameters have potential as bioimaging markers to monitor OA susceptibility and progression. Additionally, significant age/strain interaction effects were identified for total epiphyseal volume, marrow space volume and trabecular BV/TV. These interactions confirm that the two mouse strains have different epiphyseal growth patterns throughout life, some of which emerge prior to OA onset. Our findings not only propose valuable imaging biomarkers of OA, but also provide insight into ageing 3D epiphyseal architecture bone profiles and skeletal biology underlying the onset and development of age-related OA in STR/Ort mice.
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Affiliation(s)
- Eva C. Herbst
- Palaeontological Institute & MuseumUniversity of ZurichZurichSwitzerland
- Skeletal Biology Group, Comparative Biomedical SciencesRoyal Veterinary CollegeLondonUK
| | - Lucinda A. E. Evans
- Skeletal Biology Group, Comparative Biomedical SciencesRoyal Veterinary CollegeLondonUK
| | - Alessandro A. Felder
- Skeletal Biology Group, Comparative Biomedical SciencesRoyal Veterinary CollegeLondonUK
- Research Software Development Group, Advanced Research ComputingUniversity College LondonLondonUK
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical SciencesRoyal Veterinary CollegeLondonUK
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical SciencesRoyal Veterinary CollegeLondonUK
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8
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Houston DA, Stephen LA, Jayash SN, Myers K, Little K, Hopkinson M, Pitsillides AA, MacRae VE, Millan JL, Staines KA, Farquharson C. Increased PHOSPHO1 and alkaline phosphatase expression during the anabolic bone response to intermittent parathyroid hormone delivery. Cell Biochem Funct 2023; 41:189-201. [PMID: 36540015 PMCID: PMC10946561 DOI: 10.1002/cbf.3772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
The administration of intermittent parathyroid hormone (iPTH) is anabolic to the skeleton. Recent studies with cultured osteoblasts have revealed that the expression of PHOSPHO1, a bone-specific phosphatase essential for the initiation of mineralisation, is regulated by PTH. Therefore, this study sought to determine whether the bone anabolic response to iPTH involves modulation of expression of Phospho1 and of other enzymes critical for bone matrix mineralisation. To mimic iPTH treatment, primary murine osteoblasts were challenged with 50 nM PTH for 6 h in every 48 h period for 8 days (4 cycles), 14 days (7 cycles) and 20 days (10 cycles) in total. The expression of both Phospho1 and Smpd3 was almost completely inhibited after 4 cycles, whereas 10 cycles were required to stimulate a similar response in Alpl expression. To explore the in vivo role of PHOSPHO1 in PTH-mediated osteogenesis, the effects of 14- and 28-day iPTH (80 µg/kg/day) administration was assessed in male wild-type (WT) and Phospho1-/- mice. The expression of Phospho1, Alpl, Smpd3, Enpp1, Runx2 and Trps1 expression was enhanced in the femora of WT mice following iPTH administration but remained unchanged in the femora of Phospho1-/- mice. After 28 days of iPTH administration, the anabolic response in the femora of WT was greater than that noted in Phospho1-/- mice. Specifically, cortical and trabecular bone volume/total volume, as well as cortical thickness, were increased in femora of iPTH-treated WT but not in iPTH-treated Phospho1-/- mice. Trabecular bone osteoblast number was also increased in iPTH-treated WT mice but not in iPTH-treated Phospho1-/- mice. The increased levels of Phospho1, Alpl, Enpp1 and Smpd3 in WT mice in response to iPTH administration is consistent with their contribution to the potent anabolic properties of iPTH in bone. Furthermore, as the anabolic response to iPTH was attenuated in mice deficient in PHOSPHO1, this suggests that the osteoanabolic effects of iPTH are at least partly mediated via bone mineralisation processes.
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Affiliation(s)
- Dean A. Houston
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Louise A. Stephen
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Soher N. Jayash
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Katherine Myers
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Kirsty Little
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Mark Hopkinson
- Comparative Biomedical SciencesThe Royal Veterinary CollegeLondonUK
| | | | - Vicky E. MacRae
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Jose Luis Millan
- Human Genetics ProgramSanford Burnham Prebys Medical Discovery InstituteLa JollaCaliforniaUSA
| | - Katherine A. Staines
- School of Applied Sciences, Centre for Stress and Age‐Related DiseaseUniversity of BrightonBrightonUK
| | - Colin Farquharson
- Functional Genetics Division, The Roslin Institute and Royal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
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9
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Marr N, Zamboulis DE, Werling D, Felder AA, Dudhia J, Pitsillides AA, Thorpe CT. The tendon interfascicular basement membrane provides a vascular niche for CD146+ cell subpopulations. Front Cell Dev Biol 2023; 10:1094124. [PMID: 36699014 PMCID: PMC9869387 DOI: 10.3389/fcell.2022.1094124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/23/2022] [Indexed: 01/11/2023] Open
Abstract
Introduction: The interfascicular matrix (IFM; also known as the endotenon) is critical to the mechanical adaptations and response to load in energy-storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT). We hypothesized that the IFM is a tendon progenitor cell niche housing an exclusive cell subpopulation. Methods: Immunolabelling of equine superficial digital flexor tendon was used to identify the interfascicular matrix niche, localising expression patterns of CD31 (endothelial cells), Desmin (smooth muscle cells and pericytes), CD146 (interfascicular matrix cells) and LAMA4 (interfascicular matrix basement membrane marker). Magnetic-activated cell sorting was employed to isolate and compare in vitro properties of CD146+ and CD146- subpopulations. Results: Labelling for CD146 using standard histological and 3D imaging of large intact 3D segments revealed an exclusive interfascicular cell subpopulation that resides in proximity to a basal lamina which forms extensive, interconnected vascular networks. Isolated CD146+ cells exhibited limited mineralisation (osteogenesis) and lipid production (adipogenesis). Discussion: This study demonstrates that the interfascicular matrix is a unique tendon cell niche, containing a vascular-rich network of basement membrane, CD31+ endothelial cells, Desmin+ mural cells, and CD146+ cell populations that are likely essential to tendon structure and/or function. Contrary to our hypothesis, interfascicular CD146+ subpopulations did not exhibit stem cell-like phenotypes. Instead, our results indicate CD146 as a pan-vascular marker within the tendon interfascicular matrix. Together with previous work demonstrating that endogenous tendon CD146+ cells migrate to sites of injury, our data suggest that their mobilisation to promote intrinsic repair involves changes in their relationships with local interfascicular matrix vascular and basement membrane constituents.
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Affiliation(s)
- Neil Marr
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom,*Correspondence: Neil Marr,
| | - Danae E. Zamboulis
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Dirk Werling
- Pathobiology and Population Sciences, Centre for Vaccinology and Regenerative Medicine, Royal Veterinary College, Hatfield, United Kingdom
| | - Alessandro A. Felder
- Research Software Development Group, Advanced Research Computing, University College London, London, United Kingdom
| | - Jayesh Dudhia
- Clinical Sciences and Services, Royal Veterinary College, Hatfield, United Kingdom
| | | | - Chavaunne T. Thorpe
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
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10
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Sharma A, Michels LV, Pitsillides AA, Greeves J, Plotkin LI, Cardo V, Sims NA, Clarkin CE. Sexing Bones: Improving Transparency of Sex Reporting to Address Bias Within Preclinical Studies. J Bone Miner Res 2023; 38:5-13. [PMID: 36301601 PMCID: PMC10099537 DOI: 10.1002/jbmr.4729] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/11/2022] [Accepted: 10/20/2022] [Indexed: 01/10/2023]
Abstract
Despite knowledge that sexually dimorphic mechanisms regulate bone homeostasis, sex often remains unreported and unconsidered in preclinical experimental design. Failure to report sex could lead to inappropriate generalizations of research findings and less effective translation into clinical practice. Preclinical sex bias (preferential selection of one sex) is present across other fields, including neuroscience and immunology, but remains uninvestigated in skeletal research. For context, we first summarized key literature describing sexually dimorphic bone phenotypes in mice. We then investigated sex reporting practices in skeletal research, specifically how customary it is for murine sex to be included in journal article titles or abstracts and then determined whether any bias in sex reporting exists. Because sex hormones are important regulators of bone health (gonadectomy procedures, ie, ovariectomy [OVX] and orchidectomy [ORX], are common yet typically not reported with sex), we incorporated reporting of OVX and ORX terms, representing female and male mice, respectively, into our investigations around sex bias. Between 1999 and 2020, inclusion of sex in titles or abstracts was low in murine skeletal studies (2.6%-4.06%). Reporting of OVX and ORX terms was low (1.44%-2.64%) and reporting of OVX and ORX with sex uncommon (0.4%-0.3%). When studies were combined to include both sexes and OVX (representing female) and ORX terms (representing male), a bias toward reporting of female mice was evident. However, when the terms OVX and ORX were removed, a bias toward the use of male mice was identified. Thus, studies focusing on sex hormones are biased toward female reporting with all other studies biased in reporting of male mice. We now call upon journal editors to introduce consistent guidance for transparent and accessible reporting of murine sex in skeletal research to better monitor preclinical sex bias, to diversify development of treatments for bone health, and to enable global skeletal health equity. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Aikta Sharma
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Lysanne V Michels
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Julie Greeves
- Army Health and Performance Research, Ministry of Defence, Andover, UK
| | - Lillian I Plotkin
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, USA
| | - Valentina Cardo
- Winchester School of Art, University of Southampton, Winchester, UK
| | - Natalie A Sims
- Department of Medicine at St. Vincent's Hospital, St. Vincent's Institute of Medical Research and The University of Melbourne, Fitzroy, Australia
| | - Claire E Clarkin
- School of Biological Sciences, University of Southampton, Southampton, UK
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11
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Evans LAE, Pitsillides AA. Structural clues to articular calcified cartilage function: A descriptive review of this crucial interface tissue. J Anat 2022; 241:875-895. [PMID: 35866709 PMCID: PMC9482704 DOI: 10.1111/joa.13728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 06/26/2022] [Accepted: 06/30/2022] [Indexed: 11/26/2022] Open
Abstract
Articular calcified cartilage (ACC) has been dismissed, by some, as a remnant of endochondral ossification without functional relevance to joint articulation or weight-bearing. Recent research indicates that morphologic and metabolic ACC features may be important, reflecting knee joint osteoarthritis (OA) predisposition. ACC is less investigated than neighbouring joint tissues, with its component chondrocytes and mineralised matrix often being either ignored or integrated into analyses of hyaline articular cartilage and subchondral bone tissue respectively. Anatomical variation in ACC is recognised between species, individuals and age groups, but the selective pressures underlying this variation are unknown. Consequently, optimal ACC biomechanical features are also unknown as are any potential locomotory roles. This review collates descriptions of ACC anatomy and biology in health and disease, with a view to revealing its structure/function relationship and highlighting potential future research avenues. Mouse models of healthy and OA joint ageing have shown disparities in ACC load-induced deformations at the knee joint. This raises the hypothesis that ACC response to locomotor forces over time may influence, or even underlie, the bony and hyaline cartilage symptoms characteristic of OA. To effectively investigate the ACC, greater resolution of joint imaging and merging of hierarchical scale data will be required. An appreciation of OA as a 'whole joint disease' is expanding, as is the possibility that the ACC may be a key player in healthy ageing and in the transition to OA joint pathology.
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Affiliation(s)
- Lucinda A. E. Evans
- Department of Comparative Biomedical SciencesRoyal Veterinary College, University of LondonLondonUK
| | - Andrew A. Pitsillides
- Department of Comparative Biomedical SciencesRoyal Veterinary College, University of LondonLondonUK
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12
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Louka P, Orriss IR, Pitsillides AA. High bone mass in mice can be linked to lower osteoclast formation, resorptive capacity, and restricted in vitro sensitivity to inhibition by stable sulforaphane. Cell Biochem Funct 2022; 40:683-693. [PMID: 35924674 DOI: 10.1002/cbf.3734] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/05/2022] [Accepted: 07/22/2022] [Indexed: 01/07/2023]
Abstract
Mouse strains can have divergent basal bone mass, yet this phenotype is seldom reflected in the design of studies seeking to identify new modulators of bone resorption by osteoclasts. Sulforaphane exerts inhibitory effects on in vitro osteoclastogenesis in cells from C57BL/6 mice. Here, we explore whether a divergent basal bone mass in different mouse strains is linked both to in vitro osteoclastogenic potential and to SFX-01 sensitivity. Accordingly, osteoclasts isolated from the bone marrow (BM) of C57BL/6, STR/Ort and CBA mice with low, high, and intermediate bone mass, respectively, were cultured under conditions to promote osteoclast differentiation and resorption; they were also treated with chemically stabilised sulforaphane (SFX-01) and respective sensitivity to inhibition evaluated by counting osteoclast number/resorption activity on dentine discs. We observed that osteoclastogenesis exhibited different macrophage colony-stimulating factor/receptor activator of nuclear factor kappa-Β ligand sensitivity in these mouse strains, with cells from C57BL/6 and CBA generating higher osteoclast numbers than STR/Ort; the latter formed only half as many mature osteoclasts. We found that 100 nM SFX-01 exerted a potent and significant reduction in osteoclast number and resorptive activity in cells derived from C57BL/6 mice. In contrast, 10-fold higher SFX-01 concentrations were required for similar inhibition in CBA-derived cells and, strikingly, a further 2.5-fold greater concentration was required for significant restriction of osteoclast formation/function in STR/Ort. These data are consistent with the notion that the BM osteoclast precursor population contributes to the relative differences in mouse bone mass and that mice with higher bone mass exhibit lower in vitro osteoclastogenic potential as well as reduced sensitivity to inhibition by SFX-01.
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Affiliation(s)
- Polymnia Louka
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Isabel R Orriss
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
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13
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Hsu SN, Stephen LA, Dillon S, Milne E, Javaheri B, Pitsillides AA, Novak A, Millán JL, MacRae VE, Staines KA, Farquharson C. Increased PHOSPHO1 expression mediates cortical bone mineral density in renal osteodystrophy. J Endocrinol 2022; 254:153-167. [PMID: 35900032 PMCID: PMC9422252 DOI: 10.1530/joe-22-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/25/2022] [Indexed: 11/08/2022]
Abstract
Patients with advanced chronic kidney disease (CKD) often present with skeletal abnormalities, a condition known as renal osteodystrophy (ROD). While tissue non-specific alkaline phosphatase (TNAP) and PHOSPHO1 are critical for bone mineralization, their role in the etiology of ROD is unclear. To address this, ROD was induced in both WT and Phospho1 knockout (P1KO) mice through dietary adenine supplementation. The mice presented with hyperphosphatemia, hyperparathyroidism, and elevated levels of FGF23 and bone turnover markers. In particular, we noted that in CKD mice, bone mineral density (BMD) was increased in cortical bone (P < 0.05) but decreased in trabecular bone (P < 0.05). These changes were accompanied by decreased TNAP (P < 0.01) and increased PHOSPHO1 (P < 0.001) expression in WT CKD bones. In P1KO CKD mice, the cortical BMD phenotype was rescued, suggesting that the increased cortical BMD of CKD mice was driven by increased PHOSPHO1 expression. Other structural parameters were also improved in P1KO CKD mice. We further investigated the driver of the mineralization defects, by studying the effects of FGF23, PTH, and phosphate administration on PHOSPHO1 and TNAP expression by primary murine osteoblasts. We found both PHOSPHO1 and TNAP expressions to be downregulated in response to phosphate and PTH. The in vitro data suggest that the TNAP reduction in CKD-MBD is driven by the hyperphosphatemia and/or hyperparathyroidism noted in these mice, while the higher PHOSPHO1 expression may be a compensatory mechanism. Increased PHOSPHO1 expression in ROD may contribute to the disordered skeletal mineralization characteristic of this progressive disorder.
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Affiliation(s)
- Shun-Neng Hsu
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Louise A Stephen
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Scott Dillon
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Elspeth Milne
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Behzad Javaheri
- Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | | | - Amanda Novak
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Jose Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Vicky E MacRae
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Katherine A Staines
- Centre for Stress and Age-Related Disease, University of Brighton, Brighton, UK
| | - Colin Farquharson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
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14
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Javaheri B, Pitsillides AA. Correction to: Aging and Mechanoadaptive Responsiveness of Bone. Curr Osteoporos Rep 2022; 20:227. [PMID: 31907726 DOI: 10.1007/s11914-019-00556-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.
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15
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Ajami S, Javaheri B, Chang YM, Maruthainar N, Khan T, Donaldson J, Pitsillides AA, Liu C. Spatial links between subchondral bone architectural features and cartilage degeneration in osteoarthritic joints. Sci Rep 2022; 12:6694. [PMID: 35461315 PMCID: PMC9035167 DOI: 10.1038/s41598-022-10600-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/06/2022] [Indexed: 11/09/2022] Open
Abstract
Early diagnosis of osteoarthritis (OA), before the onset of irreversible changes is crucial for understanding the disease process and identifying potential disease-modifying treatments from the earliest stage. OA is a whole joint disease and affects both cartilage and the underlying subchondral bone. However, spatial relationships between cartilage lesion severity (CLS) and microstructural changes in subchondral plate and trabecular bone remain elusive. Herein, we collected femoral heads from hip arthroplasty for primary osteoarthritis (n = 7) and femoral neck fracture (n = 6; non-OA controls) cases. Samples were regionally assessed for cartilage lesions by visual inspection using Outerbridge classification and entire femoral heads were micro-CT scanned. Scans of each femoral head were divided into 4 quadrants followed by morphometric analysis of subchondral plate and trabecular bone in each quadrant. Principal component analysis (PCA), a data reduction method, was employed to assess differences between OA and non-OA samples, and spatial relationship between CLS and subchondral bone changes. Mapping of the trabecular bone microstructure in OA patients with low CLS revealed trabecular organisation resembling non-OA patients, whereas clear differences were identifiable in subchondral plate architecture. The OA-related changes in subchondral plate architecture were summarised in the first principle component (PC1) which correlated with CLS in all quadrants, whilst by comparison such associations in trabecular bone were most prominent in the higher weight-bearing regions of the femoral head. Greater articular cartilage deterioration in OA was regionally-linked with lower BV/TV, TMD and thickness, and greater BS/BV and porosity in the subchondral plate; and with thinner, less separated trabeculae with greater TMD and BS/BV in the trabecular bone. Our findings suggest that impairment of subchondral bone microstructure in early stage of OA is more readily discernible in the cortical plate and that morphological characterisation of the femoral head bone microstructure may allow for earlier OA diagnosis and monitoring of progression.
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Affiliation(s)
- Sara Ajami
- Institute of Orthopaedics and Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK. .,Great Ormond Street Institute of Child Health, University College London, London, WC1N 1EH, UK.
| | - Behzad Javaheri
- School of Mathematics, Computer Science and Engineering, City University of London, London, UK
| | - Y-M Chang
- Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | | | - Tahir Khan
- The Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK
| | - James Donaldson
- The Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Chaozong Liu
- Institute of Orthopaedics and Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK.
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16
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Jones GMC, Pitsillides AA, Meeson RL. Moving Beyond the Limits of Detection: The Past, the Present, and the Future of Diagnostic Imaging in Canine Osteoarthritis. Front Vet Sci 2022; 9:789898. [PMID: 35372534 PMCID: PMC8964951 DOI: 10.3389/fvets.2022.789898] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/17/2022] [Indexed: 12/13/2022] Open
Abstract
Osteoarthritis (OA) is the most common orthopedic condition in dogs, characterized as the chronic, painful end-point of a synovial joint with limited therapeutic options other than palliative pain control or surgical salvage. Since the 1970s, radiography has been the standard-of-care for the imaging diagnosis of OA, despite its known limitations. As newer technologies have been developed, the limits of detection have lowered, allowing for the identification of earlier stages of OA. Identification of OA at a stage where it is potentially reversible still remains elusive, however, yet there is hope that newer technologies may be able to close this gap. In this article, we review the changes in the imaging of canine OA over the past 50 years and give a speculative view on future innovations which may provide for earlier identification, with the ultimate goal of repositioning the limit of detection to cross the threshold of this potentially reversible disease.
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Affiliation(s)
- Gareth M. C. Jones
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
| | - Andrew A. Pitsillides
- Department of Comparative Biological Science, Royal Veterinary College, London, United Kingdom
| | - Richard L. Meeson
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
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17
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Santos-Beato P, Midha S, Pitsillides AA, Miller A, Torii R, Kalaskar DM. Biofabrication of the osteochondral unit and its applications: Current and future directions for 3D bioprinting. J Tissue Eng 2022; 13:20417314221133480. [PMID: 36386465 PMCID: PMC9643769 DOI: 10.1177/20417314221133480] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/30/2022] [Indexed: 07/20/2023] Open
Abstract
Multiple prevalent diseases, such as osteoarthritis (OA), for which there is no cure or full understanding, affect the osteochondral unit; a complex interface tissue whose architecture, mechanical nature and physiological characteristics are still yet to be successfully reproduced in vitro. Although there have been multiple tissue engineering-based approaches to recapitulate the three dimensional (3D) structural complexity of the osteochondral unit, there are various aspects that still need to be improved. This review presents the different pre-requisites necessary to develop a human osteochondral unit construct and focuses on 3D bioprinting as a promising manufacturing technique. Examples of 3D bioprinted osteochondral tissues are reviewed, focusing on the most used bioinks, chosen cell types and growth factors. Further information regarding the applications of these 3D bioprinted tissues in the fields of disease modelling, drug testing and implantation is presented. Finally, special attention is given to the limitations that currently hold back these 3D bioprinted tissues from being used as models to investigate diseases such as OA. Information regarding improvements needed in bioink development, bioreactor use, vascularisation and inclusion of additional tissues to further complete an OA disease model, are presented. Overall, this review gives an overview of the evolution in 3D bioprinting of the osteochondral unit and its applications, as well as further illustrating limitations and improvements that could be performed explicitly for disease modelling.
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Affiliation(s)
| | - Swati Midha
- Kennedy Institute of Rheumatology,
University of Oxford, Oxford, UK
| | | | - Aline Miller
- Department of Chemical Engineering,
University of Manchester, Manchester, UK
| | - Ryo Torii
- Department of Mechanical Engineering,
University College London, London, UK
| | - Deepak M Kalaskar
- Institute of Orthopaedics and
Musculoskeletal Science, Division of Surgery & Interventional Science,
University College London (UCL), UK
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18
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Caetano-Silva S, Simbi BH, Marr N, Hibbert A, Allen SP, Pitsillides AA. Restraint upon Embryonic Metatarsal Ex Vivo Growth by Hydrogel Reveals Interaction between Quasi-Static Load and the mTOR Pathway. Int J Mol Sci 2021; 22:ijms222413220. [PMID: 34948015 PMCID: PMC8706285 DOI: 10.3390/ijms222413220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 11/23/2022] Open
Abstract
Mechanical cues play a vital role in limb skeletal development, yet their influence and underpinning mechanisms in the regulation of endochondral ossification (EO) processes are incompletely defined. Furthermore, interactions between endochondral growth and mechanics and the mTOR/NF-ĸB pathways are yet to be explored. An appreciation of how mechanical cues regulate EO would also clearly be beneficial in the context of fracture healing and bone diseases, where these processes are recapitulated. The study herein addresses the hypothesis that the mTOR/NF-ĸB pathways interact with mechanics to control endochondral growth. To test this, murine embryonic metatarsals were incubated ex vivo in a hydrogel, allowing for the effects of quasi-static loading on longitudinal growth to be assessed. The results showed significant restriction of metatarsal growth under quasi-static loading during a 14-day period and concentration-dependent sensitivity to hydrogel-related restriction. This study also showed that hydrogel-treated metatarsals retain their viability and do not present with increased apoptosis. Metatarsals exhibited reversal of the growth-restriction when co-incubated with mTOR compounds, whilst it was found that these compounds showed no effects under basal culture conditions. Transcriptional changes linked to endochondral growth were assessed and downregulation of Col2 and Acan was observed in hydrogel-treated metatarsi at day 7. Furthermore, cell cycle analyses confirmed the presence of chondrocytes exhibiting S-G2/M arrest. These data indicate that quasi-static load provokes chondrocyte cell cycle arrest, which is partly overcome by mTOR, with a less marked interaction for NF-ĸB regulators.
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19
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Ferrao Blanco MN, Bastiaansen-Jenniskens YM, Chambers MG, Pitsillides AA, Narcisi R, van Osch GJ. Effect of Inflammatory Signaling on Human Articular Chondrocyte Hypertrophy: Potential Involvement of Tissue Repair Macrophages. Cartilage 2021; 13:168S-174S. [PMID: 34165367 PMCID: PMC8739598 DOI: 10.1177/19476035211021907] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE In osteoarthritis, chondrocytes tend to acquire a hypertrophic phenotype, which contributes to the modification of the extracellular matrix, resulting in permanent cartilage changes. In mouse chondrocytes, pro-inflammatory macrophages and pro-inflammatory cytokines have been shown to stimulate hypertrophy via the activation of the nuclear factor kappa B (NF-κB) pathway. Whether or not this also occurs in human chondrocytes remains unclear. We therefore aimed to investigate whether hypertrophy-like responses in human cartilage are driven mainly by intrinsic inflammatory signaling or shaped by specific macrophage populations. DESIGN Human articular chondrocytes were cultured with pro-inflammatory cytokines or medium conditioned by defined macrophage subsets. Furthermore, the effect of inhibition of NF-κB-dependent gene expression was evaluated using the NF-κB inhibitor SC-514. Hypertrophy was assessed by measuring the transcription level of alkaline phosphatase (ALPL), type X collagen (COL10A1), Indian hedgehog (IHH), and runt-related transcription factor 2 (RUNX2). RESULTS The expression of hypertrophic genes was not promoted in human chondrocytes by pro-inflammatory cytokines neither pro-inflammatory M(IFNγ + TNFα) macrophages. Inhibition of the NF-κB-dependent gene expression did not affect human articular chondrocyte hypertrophy. However, tissue repair M(IL4) macrophages induced hypertrophy by promoting the expression of COL10A1, RUNX2, and IHH. CONCLUSION Intrinsic inflammatory signaling activation is not involved in the hypertrophic shift observed in human articular chondrocytes cultured in vitro. However, tissue repair macrophages may contribute to the onset of this detrimental phenotype in human osteoarthritic cartilage, given the effect observed in our experimental models.
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Affiliation(s)
- Mauricio N. Ferrao Blanco
- Department of Orthopaedics and
Sports Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam,
The Netherlands
| | | | - Mark G. Chambers
- Lilly Research Laboratories, Eli
Lilly Pharmaceuticals, Indianapolis, IN, USA
| | | | - Roberto Narcisi
- Department of Orthopaedics and
Sports Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam,
The Netherlands
| | - Gerjo J.V.M. van Osch
- Department of Orthopaedics and
Sports Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam,
The Netherlands,Department of
Otorhinolaryngology, Erasmus MC, University Medical Center Rotterdam,
Rotterdam, The Netherlands,Department of Biomechanical
Engineering, TU Delft, Delft, The Netherlands,Gerjo J.V.M. van Osch, Erasmus MC,
University Medical Center Rotterdam, Wytemaweg 80, Room Ee 16.51b,
Rotterdam, 3015 CN, The Netherlands.
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20
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Affiliation(s)
- Andrew A Pitsillides
- Skeletal Biology Group, Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK.
| | - Frank Beier
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada. .,Bone and Joint Institute, University of Western Ontario, London, Ontario, Canada.
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21
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Marr N, Meeson R, Kelly EF, Fang Y, Peffers MJ, Pitsillides AA, Dudhia J, Thorpe CT. CD146 Delineates an Interfascicular Cell Sub-Population in Tendon That Is Recruited during Injury through Its Ligand Laminin-α4. Int J Mol Sci 2021; 22:9729. [PMID: 34575887 PMCID: PMC8472220 DOI: 10.3390/ijms22189729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/02/2021] [Accepted: 09/05/2021] [Indexed: 12/18/2022] Open
Abstract
The interfascicular matrix (IFM) binds tendon fascicles and contains a population of morphologically distinct cells. However, the role of IFM-localised cell populations in tendon repair remains to be determined. The basement membrane protein laminin-α4 also localises to the IFM. Laminin-α4 is a ligand for several cell surface receptors, including CD146, a marker of pericyte and progenitor cells. We used a needle injury model in the rat Achilles tendon to test the hypothesis that the IFM is a niche for CD146+ cells that are mobilised in response to tendon damage. We also aimed to establish how expression patterns of circulating non-coding RNAs alter with tendon injury and identify potential RNA-based markers of tendon disease. The results demonstrate the formation of a focal lesion at the injury site, which increased in size and cellularity for up to 21 days post injury. In healthy tendon, CD146+ cells localised to the IFM, compared with injury, where CD146+ cells migrated towards the lesion at days 4 and 7, and populated the lesion 21 days post injury. This was accompanied by increased laminin-α4, suggesting that laminin-α4 facilitates CD146+ cell recruitment at injury sites. We also identified a panel of circulating microRNAs that are dysregulated with tendon injury. We propose that the IFM cell niche mediates the intrinsic response to injury, whereby an injury stimulus induces CD146+ cell migration. Further work is required to fully characterise CD146+ subpopulations within the IFM and establish their precise roles during tendon healing.
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Affiliation(s)
- Neil Marr
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK; (N.M.); (A.A.P.)
| | - Richard Meeson
- Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK; (R.M.); (E.F.K.); (J.D.)
| | - Elizabeth F. Kelly
- Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK; (R.M.); (E.F.K.); (J.D.)
| | - Yongxiang Fang
- Centre for Genomic Research, Institute of Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
| | - Mandy J. Peffers
- Institute of Ageing and Chronic Disease, University of Liverpool, Apex Building, 6 West Derby Street, Liverpool L7 9TX, UK;
| | - Andrew A. Pitsillides
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK; (N.M.); (A.A.P.)
| | - Jayesh Dudhia
- Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK; (R.M.); (E.F.K.); (J.D.)
| | - Chavaunne T. Thorpe
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK; (N.M.); (A.A.P.)
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22
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Herbst EC, Felder AA, Evans LAE, Ajami S, Javaheri B, Pitsillides AA. A new straightforward method for semi-automated segmentation of trabecular bone from cortical bone in diverse and challenging morphologies. R Soc Open Sci 2021; 8:210408. [PMID: 34386254 PMCID: PMC8334830 DOI: 10.1098/rsos.210408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Many physiological, biomechanical, evolutionary and clinical studies that explore skeletal structure and function require successful separation of trabecular from cortical compartments of a bone that has been imaged by X-ray micro-computed tomography (micro-CT) prior to analysis. Separation often involves manual subdivision of these two similarly radio-opaque compartments, which can be time-consuming and subjective. We have developed an objective, semi-automated protocol which reduces user bias and enables straightforward, user-friendly segmentation of trabecular from the cortical bone without requiring sophisticated programming expertise. This method can conveniently be used as a 'recipe' in commercial programmes (Avizo herein) and applied to a variety of datasets. Here, we characterize and share this recipe, and demonstrate its application to a range of murine and human bone types, including normal and osteoarthritic specimens, and bones with distinct embryonic origins and spanning a range of ages. We validate the method by testing inter-user bias during the scan preparation steps and confirm utility in the architecturally challenging analysis of growing murine epiphyses. We also report details of the recipe, so that other groups can readily re-create a similar method in open access programmes. Our aim is that this method will be adopted widely to create a reproducible and time-efficient method of segmenting trabecular and cortical bone.
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Affiliation(s)
- Eva C. Herbst
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Alessandro A. Felder
- Research Software Development Group, Research IT Services, University College London, London, UK
| | - Lucinda A. E. Evans
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Sara Ajami
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Behzad Javaheri
- School of Mathematics, Computer Science and Engineering, City University of London, London, UK
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
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23
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Chang YM, Menges S, Westhof A, Kleinschmidt-Doerr K, Brenneis C, Pitsillides AA. Systematic analysis reveals that colony housing aligns gait profiles and strengthens link between histological and micro-CT bone markers in rat models of osteoarthritis. FASEB J 2021; 35:e21451. [PMID: 33683776 DOI: 10.1096/fj.202002009r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/01/2021] [Accepted: 02/01/2021] [Indexed: 11/11/2022]
Abstract
Osteoarthritis (OA) etiopathogenesis is complex with strong environmental/lifestyle determinants that, in laboratory animals, extend to social context and stress levels. This study seeks to identify whether colony housing of rats exerts a social impact on locomotion behaviors to influence alignment between symptomatic (gait) and structural (bone micro-CT measures, cartilage morphometry, and histology) OA outcome measures. Rats were randomly allocated to conventional (type IV; n = 48) or rat colony cage (RCC; n = 30) housing, further randomized to OA surgical models (ACLT + tMx, MMT or DMM) or no surgery (control), and maintained for 19 weeks during which multiple gait recordings were made. Standard histological grading and bone micro-CT data were collected at necropsy. Principal component analysis was used to summarize the variation in gait, micro-CT or histology. Linear mixed effects model or two-way ANOVA was employed to evaluate the impact of the housing system, surgery and time on gait, or micro-CT and histology components Analyses reveal that RCC exaggerates trends in gait change via a combined effect of the housing system and surgery. Intriguingly, RCC-housed nonoperated control rats showed similar gait changes to rats subjected to surgery; the latter exhibited significant structural joint changes in both systems. Stronger correlation between histological and micro-CT bone changes were found in medial and lateral tibia joint compartments of rats housed in RCC system. This study has established that rat social housing exaggerates outcomes in traditional histological measures of OA, generates stronger links between histology and micro-CT bone changes and removes gait differences as a variable in their etiology.
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Affiliation(s)
- Yu-Mei Chang
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | | | | | | | | | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
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24
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Sharma A, Goring A, Johnson PB, Emery RJH, Hesse E, Boyde A, Olsen BR, Pitsillides AA, Oreffo ROC, Mahajan S, Clarkin CE. Multiscale molecular profiling of pathological bone resolves sexually dimorphic control of extracellular matrix composition. Dis Model Mech 2021; 14:dmm048116. [PMID: 33563616 PMCID: PMC7988766 DOI: 10.1242/dmm.048116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/21/2021] [Indexed: 11/28/2022] Open
Abstract
Collagen assembly during development is essential for successful matrix mineralisation, which determines bone quality and mechanocompetence. However, the biochemical and structural perturbations that drive pathological skeletal collagen configuration remain unclear. Deletion of vascular endothelial growth factor (VEGF; also known as VEGFA) in bone-forming osteoblasts (OBs) induces sex-specific alterations in extracellular matrix (ECM) conformation and mineralisation coupled to vascular changes, which are augmented in males. Whether this phenotypic dimorphism arises as a result of the divergent control of ECM composition and its subsequent arrangement is unknown and is the focus of this study. Herein, we used murine osteocalcin-specific Vegf knockout (OcnVEGFKO) and performed ex vivo multiscale analysis at the tibiofibular junction of both sexes. Label-free and non-destructive polarisation-resolved second-harmonic generation (p-SHG) microscopy revealed a reduction in collagen fibre number in males following the loss of VEGF, complemented by observable defects in matrix organisation by backscattered electron scanning electron microscopy. This was accompanied by localised divergence in collagen orientation, determined by p-SHG anisotropy measurements, as a result of OcnVEGFKO. Raman spectroscopy confirmed that the effect on collagen was linked to molecular dimorphic VEGF effects on collagen-specific proline and hydroxyproline, and collagen intra-strand stability, in addition to matrix carbonation and mineralisation. Vegf deletion in male and female murine OB cultures in vitro further highlighted divergence in genes regulating local ECM structure, including Adamts2, Spp1, Mmp9 and Lama1. Our results demonstrate the utility of macromolecular imaging and spectroscopic modalities for the detection of collagen arrangement and ECM composition in pathological bone. Linking the sex-specific genetic regulators to matrix signatures could be important for treatment of dimorphic bone disorders that clinically manifest in pathological nano- and macro-level disorganisation. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Aikta Sharma
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Alice Goring
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Peter B. Johnson
- School of Chemistry and Institute for Life Sciences, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Roger J. H. Emery
- Department of Surgery and Cancer, Faculty of Medicine, St Mary's Campus, Imperial College London, London W2 1PG, UK
| | - Eric Hesse
- Institute of Molecular Musculoskeletal Research, Faculty of Medicine, LMU Munich, Planegg-Martinsried, Munich 80336, Germany
| | - Alan Boyde
- Dental Physical Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, UK
| | - Bjorn R. Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Andrew A. Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK
| | - Richard O. C. Oreffo
- Centre for Human Development, Stem Cell and Regeneration, Institute of Developmental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Sumeet Mahajan
- School of Chemistry and Institute for Life Sciences, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Claire E. Clarkin
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
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25
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Carriero A, Javaheri B, Bassir Kazeruni N, Pitsillides AA, Shefelbine SJ. Age and Sex Differences in Load-Induced Tibial Cortical Bone Surface Strain Maps. JBMR Plus 2021; 5:e10467. [PMID: 33778328 PMCID: PMC7990149 DOI: 10.1002/jbm4.10467] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/03/2021] [Indexed: 12/21/2022] Open
Abstract
Bone adapts its architecture to the applied load; however, it is still unclear how bone mechano‐adaptation is coordinated and why potential for adaptation adjusts during the life course. Previous animal models have suggested strain as the mechanical stimulus for bone adaptation, but yet it is unknown how mouse cortical bone load‐related strains vary with age and sex. In this study, full‐field strain maps (at 1 N increments up to 12 N) on the bone surface were measured in young, adult, and old (aged 10, 22 weeks, and 20 months, respectively), male and female C57BL/6J mice with load applied using a noninvasive murine tibial model. Strain maps indicate a nonuniform strain field across the tibial surface, with axial compressive loads resulting in tension on the medial side of the tibia because of its curved shape. The load‐induced surface strain patterns and magnitudes show sexually dimorphic changes with aging. A comparison of the average and peak tensile strains indicates that the magnitude of strain at a given load generally increases during maturation, with tibias in female mice having higher strains than in males. The data further reveal that postmaturation aging is linked to sexually dimorphic changes in average and maximum strains. The strain maps reported here allow for loading male and female C57BL/6J mouse legs in vivo at the observed ages to create similar increases in bone surface average or peak strain to more accurately explore bone mechano‐adaptation differences with age and sex. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Alessandra Carriero
- Department of Biomedical Engineering The City College of New York New York NY USA
| | - Behzad Javaheri
- School of Mathematics, Computer Science and Engineering, City University of London London UK
| | | | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences Royal Veterinary College London UK
| | - Sandra J Shefelbine
- Department of Mechanical and Industrial Engineering and Department of Bioengineering Northeastern University Boston MA USA
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26
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Riffault M, Johnson GP, Owen MM, Javaheri B, Pitsillides AA, Hoey DA. Loss of Adenylyl Cyclase 6 in Leptin Receptor-Expressing Stromal Cells Attenuates Loading-Induced Endosteal Bone Formation. JBMR Plus 2020; 4:e10408. [PMID: 33210061 PMCID: PMC7657397 DOI: 10.1002/jbm4.10408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Bone marrow stromal/stem cells represent a quiescent cell population that replenish the osteoblast bone‐forming cell pool with age and in response to injury, maintaining bone mass and repair. A potent mediator of stromal/stem cell differentiation in vitro and bone formation in vivo is physical loading, yet it still remains unclear whether loading‐induced bone formation requires the osteogenic differentiation of these resident stromal/stem cells. Therefore, in this study, we utilized the leptin receptor (LepR) to identify and trace the contribution of bone marrow stromal cells to mechanoadaptation of bone in vivo. Twelve‐week‐old Lepr‐cre;tdTomato mice were subjected to compressive tibia loading with an 11 N peak load for 40 cycles, every other day for 2 weeks. Histological analysis revealed that Lepr‐cre;tdTomato+ cells arise perinatally around blood vessels and populate bone surfaces as lining cells or osteoblasts before a percentage undergo osteocytogenesis. Lepr‐cre;tdTomato+ stromal cells within the marrow increase in abundance with age, but not following the application of tibial compressive loading. Mechanical loading induces an increase in bone mass and bone formation parameters, yet does not evoke an increase in Lepr‐cre;tdTomato+ osteoblasts or osteocytes. To investigate whether adenylyl cyclase‐6 (AC6) in LepR cells contributes to this mechanoadaptive response, Lepr‐cre;tdTomato mice were further crossed with AC6fl/fl mice to generate a LepR+ cell‐specific knockout of AC6. These Lepr‐cre;tdTomato;AC6fl/fl animals have an attenuated response to compressive tibia loading, characterized by a deficient load‐induced osteogenic response on the endosteal bone surface. This, therefore, shows that Lepr‐cre;tdTomato+ cells contribute to short‐term bone mechanoadaptation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Mathieu Riffault
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland
| | - Gillian P Johnson
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
| | - Madeline M Owen
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences The Royal Veterinary College London United Kingdom
| | - David A Hoey
- Trinity Centre for Biomedical Engineering Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin Ireland.,Department of Mechanical, Manufacturing, and Biomedical Engineering School of Engineering, Trinity College Dublin Dublin Ireland.,Advanced Materials and Bioengineering Research Centre (AMBER) Royal College of Surgeons in Ireland and Trinity College Dublin Dublin Ireland.,Department of Mechanical, Aeronautical and Biomedical Engineering University of Limerick Limerick Ireland
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27
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Monzem S, Ballester RY, Javaheri B, Poulet B, Sônego DA, Pitsillides AA, Souza RL. Long-term bisphosphonate treatment coupled with ovariectomy in mice provokes deleterious effects on femoral neck fracture pattern and modifies tibial shape. Bone Jt Open 2020; 1:512-519. [PMID: 33215149 PMCID: PMC7659644 DOI: 10.1302/2633-1462.19.bjo-2020-0117.r1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Aims The processes linking long-term bisphosphonate treatment to atypical fracture remain elusive. To establish a means of exploring this link, we have examined how long-term bisphosphonate treatment with prior ovariectomy modifies femur fracture behaviour and tibia mass and shape in murine bones. Methods Three groups (seven per group) of 12-week-old mice were: 1) ovariectomized and 20 weeks thereafter treated weekly for 24 weeks with 100 μm/kg subcutaneous ibandronate (OVX+IBN); 2) ovariectomized (OVX); or 3) sham-operated (SHAM). Quantitative fracture analysis generated biomechanical properties for the femoral neck. Tibiae were microCT scanned and trabecular (proximal metaphysis) and cortical parameters along almost its whole length measured. Results Fracture analyses revealed that OVX+IBN significantly reduced yield displacement (vs SHAM/OVX) and resilience, and increased stiffness (vs SHAM). OVX+IBN elevated tibial trabecular parameters and also increased cortical cross-sectional area and second moment of area around minor axis, and diminished ellipticity proximally. Conclusion These data indicate that combined ovariectomy and bisphosphonate generates cortical changes linked with greater bone brittleness and modified fracture characteristics, which may provide a basis in mice for interrogating the mechanisms and genetics of atypical fracture aetiology.Cite this article: Bone Joint Open 2020;1-9:512-519.
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Affiliation(s)
- Samuel Monzem
- Veterinary College, Federal University of Mato Grosso, Cuiaba, Mato Grosso, Brazil.,The Skeletal Biology Group - Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Rafael Y Ballester
- Biomaterials and Oral Biology Department, University of São Paulo, São Paulo, Brazil
| | - Behzad Javaheri
- The Skeletal Biology Group - Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Blandine Poulet
- Musculoskeletal Biology group, University of Liverpool Institute of Ageing and Chronic Disease, Liverpool, UK
| | - Dábila A Sônego
- Veterinary College, Federal University of Mato Grosso, Cuiaba, Mato Grosso, Brazil
| | - Andrew A Pitsillides
- The Skeletal Biology Group - Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Roberto L Souza
- Veterinary College, Federal University of Mato Grosso, Cuiaba, Mato Grosso, Brazil
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28
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Ramos-Mucci L, Javaheri B, van 't Hof R, Bou-Gharios G, Pitsillides AA, Comerford E, Poulet B. Meniscal and ligament modifications in spontaneous and post-traumatic mouse models of osteoarthritis. Arthritis Res Ther 2020; 22:171. [PMID: 32678020 PMCID: PMC7364489 DOI: 10.1186/s13075-020-02261-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Osteoarthritis (OA) is a whole joint disease that affects all joint tissues, with changes in the articular cartilage (AC), subchondral bone and synovium. Pathologies in menisci and ligaments, however, are rarely analysed, although both are known to play vital roles in the mechanical stability of the joint. The aim of our study was to describe the pathological changes in menisci and ligament during disease development in murine spontaneous and post-traumatic surgically induced OA and to quantify tissue mineralisation in the joint space using micro-computed tomography (μCT) imaging during OA progression. METHODS Knees of Str/ort mice (spontaneous OA model; 26-40 weeks) and C57CBA F1 mice following destabilisation of medial meniscus (DMM) surgery (post-traumatic OA model; 8 weeks after DMM), were used to assess histological meniscal and ligament pathologies. Joint space mineralised tissue volume was quantified by μCT. RESULTS Meniscal pathological changes in Str/ort mouse knees were associated with articular cartilage lesion severity. These meniscal changes included ossification, hyperplasia, cell hypertrophy, collagen type II deposition and Sox9 expression in the fibrous region near the attachment to the knee joint capsule. Anterior cruciate ligaments exhibited extracellular matrix changes and chondrogenesis particularly at the tibial attachment site, and ossification was seen in collateral ligaments. Similar changes were confirmed in the post-traumatic DMM model. μCT analysis showed increased joint space mineralised tissue volume with OA progression in both the post-traumatic and spontaneous OA models. CONCLUSIONS Modifications in meniscal and ligament mineralisation and chondrogenesis are seen with overt AC degeneration in murine OA. Although the aetiology and the consequences of such changes remain unknown, they will influence stability and load transmission of the joint and may therefore contribute to OA progression. In addition, these changes may have important roles in movement restriction and pain, which represent major human clinical symptoms of OA. Description of such soft tissue changes, in addition to AC degradation, should be an important aspect of future studies in mouse models in order to furnish a more complete understanding of OA pathogenesis.
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Affiliation(s)
- Lorenzo Ramos-Mucci
- Institute of Lifecourse and Medical Sciences, University of Liverpool, 6 West Derby street, L7 8TX, Liverpool, UK
| | - Behzad Javaheri
- Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Rob van 't Hof
- Institute of Lifecourse and Medical Sciences, University of Liverpool, 6 West Derby street, L7 8TX, Liverpool, UK
| | - George Bou-Gharios
- Institute of Lifecourse and Medical Sciences, University of Liverpool, 6 West Derby street, L7 8TX, Liverpool, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Eithne Comerford
- Institute of Lifecourse and Medical Sciences, University of Liverpool, 6 West Derby street, L7 8TX, Liverpool, UK
- Institute of Veterinary Science, Leahurst Campus, University of Liverpool, Chester High Rd, Neston, CH64 7TE, UK
| | - Blandine Poulet
- Institute of Lifecourse and Medical Sciences, University of Liverpool, 6 West Derby street, L7 8TX, Liverpool, UK.
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29
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Marr N, Hopkinson M, Hibbert AP, Pitsillides AA, Thorpe CT. Bimodal Whole-Mount Imaging of Tendon Using Confocal Microscopy and X-ray Micro-Computed Tomography. Biol Proced Online 2020; 22:13. [PMID: 32624710 PMCID: PMC7329428 DOI: 10.1186/s12575-020-00126-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/21/2020] [Indexed: 12/25/2022] Open
Abstract
Background Three-dimensional imaging modalities for optically dense connective tissues such as tendons are limited and typically have a single imaging methodological endpoint. Here, we have developed a bimodal procedure utilising fluorescence-based confocal microscopy and x-ray micro-computed tomography for the imaging of adult tendons to visualise and analyse extracellular sub-structure and cellular composition in small and large animal species. Results Using fluorescent immunolabelling and optical clearing, we visualised the expression of the novel cross-species marker of tendon basement membrane, laminin-α4 in 3D throughout whole rat Achilles tendons and equine superficial digital flexor tendon 5 mm segments. This revealed a complex network of laminin-α4 within the tendon core that predominantly localises to the interfascicular matrix compartment. Furthermore, we implemented a chemical drying process capable of creating contrast densities enabling visualisation and quantification of both fascicular and interfascicular matrix volume and thickness by x-ray micro-computed tomography. We also demonstrated that both modalities can be combined using reverse clarification of fluorescently labelled tissues prior to chemical drying to enable bimodal imaging of a single sample. Conclusions Whole-mount imaging of tendon allowed us to identify the presence of an extensive network of laminin-α4 within tendon, the complexity of which cannot be appreciated using traditional 2D imaging techniques. Creating contrast for x-ray micro-computed tomography imaging of tendon using chemical drying is not only simple and rapid, but also markedly improves on previously published methods. Combining these methods provides the ability to gain spatio-temporal information and quantify tendon substructures to elucidate the relationship between morphology and function.
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Affiliation(s)
- Neil Marr
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Mark Hopkinson
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Andrew P Hibbert
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
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30
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Choi H, Simpson D, Wang D, Prescott M, Pitsillides AA, Dudhia J, Clegg PD, Ping P, Thorpe CT. Heterogeneity of proteome dynamics between connective tissue phases of adult tendon. eLife 2020; 9:e55262. [PMID: 32393437 PMCID: PMC7217697 DOI: 10.7554/elife.55262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/16/2020] [Indexed: 12/29/2022] Open
Abstract
Maintenance of connective tissue integrity is fundamental to sustain function, requiring protein turnover to repair damaged tissue. However, connective tissue proteome dynamics remain largely undefined, as do differences in turnover rates of individual proteins in the collagen and glycoprotein phases of connective tissue extracellular matrix (ECM). Here, we investigate proteome dynamics in the collagen and glycoprotein phases of connective tissues by exploiting the spatially distinct fascicular (collagen-rich) and interfascicular (glycoprotein-rich) ECM phases of tendon. Using isotope labelling, mass spectrometry and bioinformatics, we calculate turnover rates of individual proteins within rat Achilles tendon and its ECM phases. Our results demonstrate complex proteome dynamics in tendon, with ~1000 fold differences in protein turnover rates, and overall faster protein turnover within the glycoprotein-rich interfascicular matrix compared to the collagen-rich fascicular matrix. These data provide insights into the complexity of proteome dynamics in tendon, likely required to maintain tissue homeostasis.
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Affiliation(s)
- Howard Choi
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Deborah Simpson
- Centre for Proteome Research, Biosciences Building, Institute of Integrative Biology, University of LiverpoolLiverpoolUnited Kingdom
| | - Ding Wang
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Mark Prescott
- Centre for Proteome Research, Biosciences Building, Institute of Integrative Biology, University of LiverpoolLiverpoolUnited Kingdom
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeLondonUnited Kingdom
| | - Jayesh Dudhia
- Department of Clinical Sciences and Services, Royal Veterinary CollegeHatfieldUnited Kingdom
| | - Peter D Clegg
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of LiverpoolLiverpoolUnited Kingdom
| | - Peipei Ping
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Chavaunne T Thorpe
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeLondonUnited Kingdom
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31
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Javaheri B, Razi H, Gohin S, Wylie S, Chang YM, Salmon P, Lee PD, Pitsillides AA. Lasting organ-level bone mechanoadaptation is unrelated to local strain. Sci Adv 2020; 6:eaax8301. [PMID: 32181340 PMCID: PMC7060058 DOI: 10.1126/sciadv.aax8301] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 12/13/2019] [Indexed: 05/23/2023]
Abstract
Bones adapt to mechanical forces according to strict principles predicting straight shape. Most bones are, however, paradoxically curved. To solve this paradox, we used computed tomography-based, four-dimensional imaging methods and computational analysis to monitor acute and chronic whole-bone shape adaptation and remodeling in vivo. We first confirmed that some acute load-induced structural changes are reversible, adhere to the linear strain magnitude regulation of remodeling activities, and are restricted to bone regions in which marked antiresorptive actions are evident. We make the novel observation that loading exerts significant lasting modifications in tibial shape and mass across extensive bone regions, underpinned by (re)modeling independent of local strain magnitude, occurring at sites where the initial response to load is principally osteogenic. This is the first report to demonstrate that bone loading stimulates nonlinear remodeling responses to strain that culminate in greater curvature adjusted for load predictability without sacrificing strength.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK
| | - Hajar Razi
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, 14424 Potsdam, Germany
- Cluster of Excellence, Humboldt University of Berlin, Berlin, Germany
| | - Stephanie Gohin
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK
| | - Sebastian Wylie
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK
| | - Yu-Mei Chang
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK
| | - Phil Salmon
- Bruker microCT, Kartuizersweg 3B, 2550 Kontich, Belgium
| | - Peter D. Lee
- Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK
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Abstract
Osteoarthritis (OA) is a global disease that, despite extensive research, has limited treatment options. Pet dogs share both an environment and lifestyle attributes with their owners, and a growing awareness is developing in the public and among researchers that One Medicine, the mutual co-study of animals and humans, could be beneficial for both humans and dogs. To that end, this Review highlights research opportunities afforded by studying dogs with spontaneous OA, with a view to sharing this active area of veterinary research with new audiences. Similarities and differences between dog and human OA are examined, and the proposition is made that suitably aligned studies of spontaneous OA in dogs and humans, in particular hip and knee OA, could highlight new avenues of discovery. Developing cross-species collaborations will provide a wealth of research material and knowledge that is relevant to human OA and that cannot currently be obtained from rodent models or experimentally induced dog models of OA. Ultimately, this Review aims to raise awareness of spontaneous dog OA and to stimulate discussion regarding its exploration under the One Medicine initiative to improve the health and well-being of both species. Osteoarthritis occurs spontaneously in pet dogs, which often share environmental and lifestyle risk-factors with their owners. This Review aims to stimulate cooperation between medical and veterinary research under the One Medicine initiative to improve the welfare of dogs and humans. Dogs have many analogous spontaneous diseases that result in end-stage osteoarthritis (OA). Inbreeding and the predisposition of certain dog breeds for OA enable easier identification of candidate genetic associations than in outbred humans. Dog OA subtypes offer a potential stratification rationale for aetiological differences and alignment to analogous human OA phenotypes. The relatively compressed time course of spontaneous dog OA offers longitudinal research opportunities. Collaboration with veterinary researchers can provide tissue samples from early-stage OA and opportunities to evaluate new therapeutics in a spontaneous disease model. Awareness of the limitations and benefits of using clinical veterinary patients in research is important.
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Affiliation(s)
- Richard L Meeson
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK.,Department of Clinical Services and Sciences, Royal Veterinary College, University of London, London, UK.,Institute of Orthopaedics and Musculoskeletal Science, University College London, London, UK
| | - Rory J Todhunter
- Department of Clinical Sciences, Cornell University, Ithaca, NY, USA.,Cornell Veterinary Biobank, Cornell University, Ithaca, NY, USA
| | - Gordon Blunn
- Institute of Orthopaedics and Musculoskeletal Science, University College London, London, UK.,School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - George Nuki
- Institute for Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK.
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Sharma A, Goring A, Staines KA, Emery RJ, Pitsillides AA, Oreffo RO, Mahajan S, Clarkin CE. Raman spectroscopy links differentiating osteoblast matrix signatures to pro-angiogenic potential. Matrix Biol Plus 2020; 5:100018. [PMID: 33543015 PMCID: PMC7852201 DOI: 10.1016/j.mbplus.2019.100018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/21/2019] [Accepted: 10/09/2019] [Indexed: 01/25/2023] Open
Abstract
Mineralization of bone is achieved by the sequential maturation of the immature amorphous calcium phase to mature hydroxyapatite (HA) and is central in the process of bone development and repair. To study normal and dysregulated mineralization in vitro, substrates are often coated with poly-l-lysine (PLL) which facilitates cell attachment. This study has used Raman spectroscopy to investigate the effect of PLL coating on osteoblast (OB) matrix composition during differentiation, with a focus on collagen specific proline and hydroxyproline and precursors of HA. Deconvolution analysis of murine derived long bone OB Raman spectra revealed collagen species were 4.01-fold higher in OBs grown on PLL. Further, an increase of 1.91-fold in immature mineral species (amorphous calcium phosphate) was coupled with a 9.32-fold reduction in mature mineral species (carbonated apatite) on PLL versus controls. These unique low mineral signatures identified in OBs were linked with reduced alkaline phosphatase enzymatic activity, reduced Alizarin Red staining and altered osteogenic gene expression. The promotion of immature mineral species and restriction of mature mineral species of OB grown on PLL were linked to increased cell viability and pro-angiogenic vascular endothelial growth factor (VEGF) production. These results demonstrate the utility of Raman spectroscopy to link distinct matrix signatures with OB maturation and VEGF release. Importantly, Raman spectroscopy could provide a label-free approach to clinically assess the angiogenic potential of bone during fracture repair or degenerative bone loss.
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Key Words
- ACP, amorphous calcium phosphate
- ALP, tissue non-specific alkaline phosphatase
- CAP, carbonated apatite
- CCEC, collagenase-collagenase-EDTA-collagenase
- ECM, extracellular matrix
- HA, hydroxyapatite
- HBSS, Hank's balanced salt solution
- MV, matrix vesicles
- OB, osteoblast
- OCP, octacalcium phosphate
- Osteoblast mineralization
- PCA, principle component analysis
- PLL, poly-l-lysine
- Poly-l-lysine
- RT-qPCR, reverse transcription-quantiative PCR
- Raman spectroscopy
- VEGF
- VEGF, vascular endothelial growth factor
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Affiliation(s)
- Aikta Sharma
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom of Great Britain and Northern Ireland
| | - Alice Goring
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom of Great Britain and Northern Ireland
| | - Katherine A. Staines
- School of Applied Sciences, Sighthill Campus, Edinburgh Napier University, Edinburgh, EH11 4BN, United Kingdom of Great Britain and Northern Ireland
| | - Roger J.H. Emery
- Department of Surgery and Cancer, Faculty of Medicine, St Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom of Great Britain and Northern Ireland
| | - Andrew A. Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, NW1 0TU, United Kingdom of Great Britain and Northern Ireland
| | - Richard O.C. Oreffo
- Centre for Human Development, Stem Cell and Regeneration, Institute of Developmental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, United Kingdom of Great Britain and Northern Ireland
| | - Sumeet Mahajan
- School of Chemistry and Institute for Life Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom of Great Britain and Northern Ireland
| | - Claire E. Clarkin
- School of Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom of Great Britain and Northern Ireland
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Clark JN, Garbout A, Ferreira SA, Javaheri B, Pitsillides AA, Rankin SM, Jeffers JRT, Hansen U. Propagation phase-contrast micro-computed tomography allows laboratory-based three-dimensional imaging of articular cartilage down to the cellular level. Osteoarthritis Cartilage 2020; 28:102-111. [PMID: 31678663 DOI: 10.1016/j.joca.2019.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/31/2019] [Accepted: 10/03/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE High-resolution non-invasive three-dimensional (3D) imaging of chondrocytes in articular cartilage remains elusive. The aim of this study was to explore whether laboratory micro-computed tomography (micro-CT) permits imaging cells within articular cartilage. DESIGN Bovine osteochondral plugs were prepared four ways: in phosphate-buffered saline (PBS) or 70% ethanol (EtOH), both with or without phosphotungstic acid (PTA) staining. Specimens were imaged with micro-CT following two protocols: 1) absorption contrast (AC) imaging 2) propagation phase-contrast (PPC) imaging. All samples were scanned in liquid. The contrast to noise ratio (C/N) of cellular features quantified scan quality and were statistically analysed. Cellular features resolved by micro-CT were validated by standard histology. RESULTS The highest quality images were obtained using propagation phase-contrast imaging and PTA-staining in 70% EtOH. Cellular features were also visualised when stained in PBS and unstained in EtOH. Under all conditions PPC resulted in greater contrast than AC (p < 0.0001 to p = 0.038). Simultaneous imaging of cartilage and subchondral bone did not impede image quality. Corresponding features were located in both histology and micro-CT and followed the same distribution with similar density and roundness values. CONCLUSIONS Three-dimensional visualisation and quantification of the chondrocyte population within articular cartilage can be achieved across a field of view of several millimetres using laboratory-based micro-CT. The ability to map chondrocytes in 3D opens possibilities for research in fields from skeletal development through to medical device design and treatment of cartilage degeneration.
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Affiliation(s)
- J N Clark
- Department of Mechanical Engineering, Imperial College London, London, UK.
| | - A Garbout
- Imaging and Analysis Centre, Natural History Museum London, London, UK.
| | - S A Ferreira
- National Heart & Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - B Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, UK.
| | - A A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, Royal Veterinary College, UK.
| | - S M Rankin
- National Heart & Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - J R T Jeffers
- Department of Mechanical Engineering, Imperial College London, London, UK.
| | - U Hansen
- Department of Mechanical Engineering, Imperial College London, London, UK.
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Abstract
PURPOSE OF REVIEW Osteoporosis is an age-related disorder characterized by bone loss and increased fracture susceptibility. Whether this is due to reduced loading in less active elderly individuals or inherent modifications in bone cells is uncertain. We suppose that osteoporosis is nonetheless prima facie evidence for impaired mechanoadaptation; either capacity to accrue new bone declines, or the stimulus for such accrual is absent/can no longer be triggered in the aged. Herein, we provide only sufficient background to enable a focus on recent advances which seek to address such dilemmas. RECENT FINDINGS Recent advances from innovative high-impact loading regimes emphasize the priming of mechanoadaptation in the aged, such that low-to-moderate intensity loading becomes beneficial. These new findings lead us to speculate that aged bone mechanoadaptation is not driven solely by strain magnitude but is instead sensitive to high strain gradients. Impaired mechanoadaptation is a feature of the aged skeleton. Recent advances indicate that novel interventional loading regimes can restore mechanoadaptive capacity, enabling new approaches for retaining bone health in the aged. Innovative exercise paradigms appear to be capable of "hacking" into the osteogenic signal produced by exercise such that low-to-moderate intensity activities may also become more beneficial. Deciphering the underpinning mechanism(s) will also enable new pharmacological intervention for retaining bone health in the aged.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.
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Goring A, Sharma A, Javaheri B, Smith RC, Kanczler JM, Boyde A, Hesse E, Mahajan S, Olsen BR, Pitsillides AA, Schneider P, Oreffo RO, Clarkin CE. Regulation of the Bone Vascular Network is Sexually Dimorphic. J Bone Miner Res 2019; 34:2117-2132. [PMID: 31269275 PMCID: PMC6899569 DOI: 10.1002/jbmr.3825] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/11/2019] [Accepted: 06/24/2019] [Indexed: 12/24/2022]
Abstract
Osteoblast (OB) lineage cells are an important source of vascular endothelial growth factor (VEGF), which is critical for bone growth and repair. During bone development, pubertal differences in males and females exist, but little is known about whether VEGF signaling contributes to skeletal sexual dimorphism. We have found that in mice, conditional disruption of VEGF in osteocalcin-expressing cells (OcnVEGFKO) exerts a divergent influence on morphological, cellular, and whole bone properties between sexes. Furthermore, we describe an underlying sexual divergence in VEGF signaling in OB cultures in vitro independent of circulating sex hormones. High-resolution synchrotron computed tomography and backscattered scanning electron microscopy revealed, in males, extensive unmineralized osteoid encasing enlarged blood vessel canals and osteocyte lacunae in cortical bone after VEGF deletion, which contributed to increased porosity. VEGF was deleted in male and female long bone-derived OBs (OBVEGKO) in vitro and Raman spectroscopic analyses of mineral and matrix repertoires highlighted differences between male and female OBVEGFKO cells, with increased immature phosphate species prevalent in male OBVEGFKO cultures versus wild type (WT). Further sexual dimorphism was observed in bone marrow endothelial cell gene expression in vitro after VEGF deletion and in sclerostin protein expression, which was increased in male OcnVEGFKO bones versus WT. The impact of altered OB matrix composition after VEGF deletion on whole bone geometry was assessed between sexes, although significant differences between OcnVEGFKO and WT were identified only in females. Our results suggest that bone-derived VEGF regulates matrix mineralization and vascularization distinctly in males and females, which results in divergent physical bone traits.
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Affiliation(s)
- Alice Goring
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Aikta Sharma
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Behzad Javaheri
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Rosanna Cg Smith
- Bone and Joint Research Group, Centre for Human Development, Stem Cell and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Janos M Kanczler
- Bone and Joint Research Group, Centre for Human Development, Stem Cell and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Alan Boyde
- Dental Physical Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Eric Hesse
- Institute of Molecular Musculoskeletal Research, Faculty of Medicine, LMU Munich, Planegg-Martinsried, Germany
| | - Sumeet Mahajan
- Institute for Life Sciences and Department of Chemistry, University of Southampton, Southampton, UK
| | - Bjorn R Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Philipp Schneider
- Bioengineering Research Group, University of Southampton, Southampton, UK
| | - Richard Oc Oreffo
- Bone and Joint Research Group, Centre for Human Development, Stem Cell and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Claire E Clarkin
- School of Biological Sciences, University of Southampton, Southampton, UK
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Crespo-Enriquez I, Hodgson T, Zakaria S, Cadoni E, Shah M, Allen S, Al-Khishali A, Mao Y, Yiu A, Petzold J, Villagomez-Olea G, Pitsillides AA, Irvine KD, Francis-West P. Dchs1-Fat4 regulation of osteogenic differentiation in mouse. Development 2019; 146:146/14/dev176776. [PMID: 31358536 DOI: 10.1242/dev.176776] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 06/20/2019] [Indexed: 12/14/2022]
Abstract
In human, mutations of the protocadherins FAT4 and DCHS1 result in Van Maldergem syndrome, which is characterised, in part, by craniofacial abnormalities. Here, we analyse the role of Dchs1-Fat4 signalling during osteoblast differentiation in mouse. We show that Fat4 and Dchs1 mutants mimic the craniofacial phenotype of the human syndrome and that Dchs1-Fat4 signalling is essential for osteoblast differentiation. In Dchs1/Fat4 mutants, proliferation of osteoprogenitors is increased and osteoblast differentiation is delayed. We show that loss of Dchs1-Fat4 signalling is linked to increased Yap-Tead activity and that Yap is expressed and required for proliferation in osteoprogenitors. In contrast, Taz is expressed in more-committed Runx2-expressing osteoblasts, Taz does not regulate osteoblast proliferation and Taz-Tead activity is unaffected in Dchs1/Fat4 mutants. Finally, we show that Yap and Taz differentially regulate the transcriptional activity of Runx2, and that the activity of Yap-Runx2 and Taz-Runx2 complexes is altered in Dchs1/Fat4 mutant osteoblasts. In conclusion, these data identify Dchs1-Fat4 as a signalling pathway in osteoblast differentiation, reveal its crucial role within the early Runx2 progenitors, and identify distinct requirements for Yap and Taz during osteoblast differentiation.
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Affiliation(s)
- Ivan Crespo-Enriquez
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Tina Hodgson
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Sana Zakaria
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Erika Cadoni
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Mittal Shah
- Comparative Biomedical Sciences, Royal Veterinary College, Camden, London, NW1 0TU, UK
| | - Stephen Allen
- Comparative Biomedical Sciences, Royal Veterinary College, Camden, London, NW1 0TU, UK
| | - Ayman Al-Khishali
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Yaopan Mao
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Angela Yiu
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Jonna Petzold
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Guillermo Villagomez-Olea
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 27, Guy's Tower, London SE1 9RT, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, Royal Veterinary College, Camden, London, NW1 0TU, UK
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
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Meeson RL, Perpétuo IP, Parsons K, Orriss IR, Shah M, Pitsillides AA, Doube M. The in vitro behaviour of canine osteoblasts derived from different bone types. BMC Vet Res 2019; 15:114. [PMID: 30975149 PMCID: PMC6460523 DOI: 10.1186/s12917-019-1857-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/28/2019] [Indexed: 12/16/2022] Open
Abstract
Background Our understanding of the biology of osteoblasts is important as they underpin bone remodelling, fracture healing and processes such as osseointegration. Osteoblasts isolated from human humeral samples display distinctive biological activity in vitro, which relates to the samples’ bone types (subchondral (S), trabecular (T), cortical (C)). Our aim was to isolate primary osteoblast cultures from different bone types from the proximal femur of a clinical population of dogs presented for total hip replacement and compare the behaviour of the osteoblasts derived from different bone types, to identify a preferred bone type for isolation. Results No differences were found for osteoblast doubling time (median for S = 2.9, T = 3.1 and C = 2.71 days, respectively; p = 0.33), final cell number (median for S = 54,849, T = 49,733, C = 61,390 cells/cm2; p = 0.34) or basal tissue non-specific alkaline phosphatase (TNAP) activity (median for S = 0.02, T = 0.02, C = 0.03 U/min/mg protein; p = 0.81) between bone types after 6 days of culture in basal media. There were no differences in mineralizing TNAP activity (S = 0.02, T = 0.02, C = 0.03 U/min/mg protein, p = 0.84) or in mineralized area (S = 0.05, T = 0.04, C = 0.04%, p = 0.92) among cells from different bone types. Conclusions There is no significant difference in mean doubling time, basal or mineralizing TNAP activity or mineralized area in osteoblasts derived from subchondral, cortical, or trabecular bone types from the canine femoral head. However, there appears to be a high level of inter-animal variability in the studied parameters, which was independent of age, body mass, and sex. Trabecular isolate osteoblasts have the least variation of the bone types studied, and therefore should be considered a preferred source for primary osteoblast cultures. The work here provides baselines for canine osteoblast function, which has utility for future comparative studies.
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Affiliation(s)
- Richard L Meeson
- Clinical Services and Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK. .,Queen Mother Hospital for Animals, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, AL9 7TA, UK.
| | - Inês P Perpétuo
- Comparative Biomedical Sciences, Skeletal Biology Group, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Kevin Parsons
- Langford Veterinary Services, University of Bristol, Langford House, Langford, BS40 5DU, UK
| | - Isabel R Orriss
- Comparative Biomedical Sciences, Skeletal Biology Group, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Mittal Shah
- Comparative Biomedical Sciences, Skeletal Biology Group, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, Skeletal Biology Group, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Michael Doube
- Comparative Biomedical Sciences, Skeletal Biology Group, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.,Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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Kanakis I, Liu K, Poulet B, Javaheri B, van 't Hof RJ, Pitsillides AA, Bou-Gharios G. Targeted Inhibition of Aggrecanases Prevents Articular Cartilage Degradation and Augments Bone Mass in the STR/Ort Mouse Model of Spontaneous Osteoarthritis. Arthritis Rheumatol 2019; 71:571-582. [PMID: 30379418 DOI: 10.1002/art.40765] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 10/25/2018] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Cartilage destruction in osteoarthritis (OA) is mediated mainly by matrix metalloproteinases (MMPs) and ADAMTS. The therapeutic candidature of targeting aggrecanases has not yet been defined in joints in which spontaneous OA arises from genetic susceptibility, as in the case of the STR/Ort mouse, without a traumatic or load-induced etiology. In addition, we do not know the long-term effect of aggrecanase inhibition on bone. We undertook this study to assess the potential aggrecanase selectivity of a variant of tissue inhibitor of metalloproteinases 3 (TIMP-3), called [-1A]TIMP-3, on spontaneous OA development and bone formation in STR/Ort mice. METHODS Using the background of STR/Ort mice, which develop spontaneous OA, we generated transgenic mice that overexpress [-1A]TIMP-3, either ubiquitously or conditionally in chondrocytes. [-1A]TIMP-3 has an extra alanine at the N-terminus that selectively inhibits ADAMTS but not MMPs. We analyzed a range of OA-related measures in all mice at age 40 weeks. RESULTS Mice expressing high levels of [-1A]TIMP-3 were protected against development of OA, while those expressing low levels were not. Interestingly, we also found that high levels of [-1A]TIMP-3 transgene overexpression resulted in increased bone mass, particularly in females. This regulation of bone mass was at least partly direct, as adult mouse primary osteoblasts infected with [-1A]TIMP-3 in vitro showed elevated rates of mineralization. CONCLUSION The results provide evidence that [-1A]TIMP-3-mediated inhibition of aggrecanases can protect against cartilage degradation in a naturally occurring mouse model of OA, and they highlight a novel role that aggrecanase inhibition may play in increased bone mass.
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Affiliation(s)
| | - Ke Liu
- University of Liverpool, Liverpool, UK
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40
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Abstract
The skeleton fulfils its mechanical functions through structural organization and material properties of individual bones. It is stated that both cortical and trabecular morphology and mass can be (re)modelled in response to changes in mechanical strains engendered by load-bearing. To address this, animal models that enable the application of specific loads to individual bones have been developed. These are useful in defining how loading modulates (re)modeling and allow examination of the mechanisms that coordinate these events. This chapter describes how to apply mechanical loading to murine bones through points of articulation, which allows changes in endosteal, periosteal as well as trabecular bone to be revealed at multiple hierarchies, by a host of methodologies, including double fluorochrome labeling and computed tomography.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Nathalie Bravenboer
- Department Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
- Center for Bone Quality and Department of Internal Medicine, Division Endocrinology, Leiden University Medical Center, Leiden, The Netherlands
| | - Astrid D Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands
| | - Albert van der Veen
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| | | | | | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, UK.
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41
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Núñez JA, Goring A, Javaheri B, Razi H, Gomez-Nicola D, Pitsillides AA, Thurner PJ, Gomez-Nicola D, Schneider P, Clarkin CE, Clarkin CE. Regional diversity in the murine cortical vascular network is revealed by synchrotron X-ray tomography and is amplified with age. Eur Cell Mater 2018; 35:281-299. [PMID: 29790567 DOI: 10.22203/ecm.v035a20] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cortical bone is permeated by a system of pores, occupied by the blood supply and osteocytes. With ageing, bone mass reduction and disruption of the microstructure are associated with reduced vascular supply. Insight into the regulation of the blood supply to the bone could enhance the understanding of bone strength determinants and fracture healing. Using synchrotron radiation-based computed tomography, the distribution of vascular canals and osteocyte lacunae was assessed in murine cortical bone and the influence of age on these parameters was investigated. The tibiofibular junction from 15-week- and 10-month-old female C57BL/6J mice were imaged post-mortem. Vascular canals and three-dimensional spatial relationships between osteocyte lacunae and bone surfaces were computed for both age groups. At 15 weeks, the posterior region of the tibiofibular junction had a higher vascular canal volume density than the anterior, lateral and medial regions. Intracortical vascular networks in anterior and posterior regions were also different, with connectedness in the posterior higher than the anterior at 15 weeks. By 10 months, cortices were thinner, with cortical area fraction and vascular density reduced, but only in the posterior cortex. This provided the first evidence of age-related effects on murine bone porosity due to the location of the intracortical vasculature. Targeting the vasculature to modulate bone porosity could provide an effective way to treat degenerative bone diseases, such as osteoporosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - C E Clarkin
- Department of Biological Sciences, University of Southampton, SO17 1BJ, Southampton,
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Javaheri B, Carriero A, Wood M, De Souza R, Lee PD, Shefelbine S, Pitsillides AA. Transient peak-strain matching partially recovers the age-impaired mechanoadaptive cortical bone response. Sci Rep 2018; 8:6636. [PMID: 29703931 PMCID: PMC5924380 DOI: 10.1038/s41598-018-25084-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/16/2018] [Indexed: 12/14/2022] Open
Abstract
Mechanoadaptation maintains bone mass and architecture; its failure underlies age-related decline in bone strength. It is unclear whether this is due to failure of osteocytes to sense strain, osteoblasts to form bone or insufficient mechanical stimulus. Mechanoadaptation can be restored to aged bone by surgical neurectomy, suggesting that changes in loading history can rescue mechanoadaptation. We use non-biased, whole-bone tibial analyses, along with characterisation of surface strains and ensuing mechanoadaptive responses in mice at a range of ages, to explore whether sufficient load magnitude can activate mechanoadaptation in aged bone. We find that younger mice adapt when imposed strains are lower than in mature and aged bone. Intriguingly, imposition of short-term, high magnitude loading effectively primes cortical but not trabecular bone of aged mice to respond. This response was regionally-matched to highest strains measured by digital image correlation and to osteocytic mechanoactivation. These data indicate that aged bone’s loading response can be partially recovered, non-invasively by transient, focal high strain regions. Our results indicate that old murine bone does respond to load when the loading is of sufficient magnitude, and bones’ age-related adaptation failure may be due to insufficient mechanical stimulus to trigger mechanoadaptation.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.
| | - Alessandra Carriero
- The City College of New York, Department of Biomedical Engineering, 160 Convent Avenue, New York, NY, 10031, USA
| | - Maria Wood
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Roberto De Souza
- Universidade Federal de Mato Grosso (UFMT), Departamento de Clínica, Av. Fernando Corrêa da Costa, 2367 - Boa Esperança, Cuiabá, 78060-900, Brazil
| | - Peter D Lee
- Manchester X-Ray Imaging Facility, University of Manchester, Research Complex at Harwell, RAL, Didcot, OX11 0FA, UK
| | - Sandra Shefelbine
- Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Ave, Boston, MA, 02115, USA
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
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43
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Boyde A, Staines KA, Javaheri B, Millan JL, Pitsillides AA, Farquharson C. A distinctive patchy osteomalacia characterises Phospho1-deficient mice. J Anat 2018; 231:298-308. [PMID: 28737011 DOI: 10.1111/joa.12628] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2017] [Indexed: 11/27/2022] Open
Abstract
The phosphatase PHOSPHO1 is involved in the initiation of biomineralisation. Bones in Phospho1 knockout (KO) mice show histological osteomalacia with frequent bowing of long bones and spontaneous fractures: they contain less mineral, with smaller mineral crystals. However, the consequences of Phospho1 ablation on the microscale structure of bone are not yet fully elucidated. Tibias and femurs obtained from wild-type and Phospho1 null (KO) mice (25-32 weeks old) were embedded in PMMA, cut and polished to produce near longitudinal sections. Block surfaces were studied using 20 kV backscattered-electron (BSE) imaging, and again after iodine staining to reveal non-mineralised matrix and cellular components. For 3D characterisation, we used X-ray micro-tomography. Bones opened with carbide milling tools to expose endosteal surfaces were macerated using an alkaline bacterial pronase enzyme detergent, 5% hydrogen peroxide and 7% sodium hypochlorite solutions to produce 3D surfaces for study with 3D BSE scanning electron microscopy (SEM). Extensive regions of both compact cortical and trabecular bone matrix in Phospho1 KO mice contained no significant mineral and/or showed arrested mineralisation fronts, characterised by a failure in the fusion of the calcospherite-like, separately mineralising, individual micro-volumes within bone. Osteoclastic resorption of the uncalcified matrix in Phospho1 KO mice was attenuated compared with surrounding normally mineralised bone. The extent and position of this aberrant biomineralisation varied considerably between animals, contralateral limbs and anatomical sites. The most frequent manifestation lay, however, in the nearly complete failure of mineralisation in the bone surrounding the numerous transverse blood vessel canals in the cortices. In conclusion, SEM disclosed defective mineralising fronts and extensive patchy osteomalacia, which has previously not been recognised. These data further confirm the role of this phosphatase in physiological skeletal mineralisation.
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Affiliation(s)
- Alan Boyde
- Dental Physical Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - Behzad Javaheri
- Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Jose Luis Millan
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | | | - Colin Farquharson
- Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, UK
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44
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Javaheri B, Caetano-Silva SP, Kanakis I, Bou-Gharios G, Pitsillides AA. The Chondro-Osseous Continuum: Is It Possible to Unlock the Potential Assigned Within? Front Bioeng Biotechnol 2018; 6:28. [PMID: 29619368 PMCID: PMC5871702 DOI: 10.3389/fbioe.2018.00028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/08/2018] [Indexed: 01/08/2023] Open
Abstract
Endochondral ossification (EO), by which long bones of the axial skeleton form, is a tightly regulated process involving chondrocyte maturation with successive stages of proliferation, maturation, and hypertrophy, accompanied by cartilage matrix synthesis, calcification, and angiogenesis, followed by osteoblast-mediated ossification. This developmental sequence reappears during fracture repair and in osteoarthritic etiopathology. These similarities suggest that EO, and the cells involved, are of great clinical importance for bone regeneration as it could provide novel targeted approaches to increase specific signaling to promote fracture healing, and if regulated appropriately in the treatment of osteoarthritis. The long-held accepted dogma states that hypertrophic chondrocytes are terminally differentiated and will eventually undergo apoptosis. In this mini review, we will explore recent evidence from experiments that revisit the idea that hypertrophic chondrocytes have pluripotent capacity and may instead transdifferentiate into a specific sub-population of osteoblast cells. There are multiple lines of evidence, including our own, showing that local, selective alterations in cartilage extracellular matrix (ECM) remodeling also indelibly alter bone quality. This would be consistent with the hypothesis that osteoblast behavior in long bones is regulated by a combination of their lineage origins and the epigenetic effects of chondrocyte-derived ECM which they encounter during their recruitment. Further exploration of these processes could help to unlock potential novel targets for bone repair and regeneration and in the treatment of osteoarthritis.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Soraia P Caetano-Silva
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Ioannis Kanakis
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - George Bou-Gharios
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
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45
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Ikpegbu E, Basta L, Clements DN, Fleming R, Vincent TL, Buttle DJ, Pitsillides AA, Staines KA, Farquharson C. FGF-2 promotes osteocyte differentiation through increased E11/podoplanin expression. J Cell Physiol 2018; 233:5334-5347. [PMID: 29215722 PMCID: PMC5900964 DOI: 10.1002/jcp.26345] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/29/2017] [Indexed: 01/15/2023]
Abstract
E11/podoplanin is critical in the early stages of osteoblast‐to‐osteocyte transitions (osteocytogenesis), however, the upstream events which regulate E11 expression are unknown. The aim of this study was to examine the effects of FGF‐2 on E11‐mediated osteocytogenesis and to reveal the nature of the underlying signaling pathways regulating this process. Exposure of MC3T3 osteoblast‐like cells and murine primary osteoblasts to FGF‐2 (10 ng/ml) increased E11 mRNA and protein expression (p < 0.05) after 4, 6, and 24 hr. FGF‐2 induced changes in E11 expression were also accompanied by significant (p < 0.01) increases in Phex and Dmp1 (osteocyte markers) expression and decreases in Col1a1, Postn, Bglap, and Alpl (osteoblast markers) expression. Immunofluorescent microscopy revealed that FGF‐2 stimulated E11 expression, facilitated the translocation of E11 toward the cell membrane, and subsequently promoted the formation of osteocyte‐like dendrites in MC3T3 and primary osteoblasts. siRNA knock down of E11 expression achieved >70% reduction of basal E11 mRNA expression (p < 0.05) and effectively abrogated FGF‐2‐related changes in E11 expression and dendrite formation. FGF‐2 strongly activated the ERK signaling pathway in osteoblast‐like cells but inhibition of this pathway did not block the ability of FGF‐2 to enhance E11 expression or to promote acquisition of the osteocyte phenotype. The results of this study highlight a novel mechanism by which FGF‐2 can regulate osteoblast differentiation and osteocyte formation. Specifically, the data suggests that FGF‐2 promotes osteocytogenesis through increased E11 expression and further studies will identify if this regulatory pathway is essential for bone development and maintenance in health and disease.
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Affiliation(s)
- Ekele Ikpegbu
- Roslin Institute and R(D)SVS, The University of Edinburgh, Edinburgh, UK.,Michael Okpara University of Agriculture, Abia, Nigeria
| | - Lena Basta
- Roslin Institute and R(D)SVS, The University of Edinburgh, Edinburgh, UK
| | - Dylan N Clements
- Roslin Institute and R(D)SVS, The University of Edinburgh, Edinburgh, UK
| | - Robert Fleming
- Roslin Institute and R(D)SVS, The University of Edinburgh, Edinburgh, UK
| | - Tonia L Vincent
- Arthritis Research UK Centre for Osteoarthritis Pathogenesis, Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - David J Buttle
- Department of Infection, Immunity & Cardiovascular Disease, The University of Sheffield Medical School, Sheffield, UK
| | | | | | - Colin Farquharson
- Roslin Institute and R(D)SVS, The University of Edinburgh, Edinburgh, UK
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Abstract
The epiphyseal growth plate is a developmental region responsible for linear bone growth, in which chondrocytes undertake a tightly regulated series of biological processes. Concomitant with the cessation of growth and sexual maturation, the human growth plate undergoes progressive narrowing, and ultimately disappears. Despite the crucial role of this growth plate fusion "bridging" event, the precise mechanisms by which it is governed are complex and yet to be established. Progress is hindered by the current methods for growth plate visualization; these are invasive and largely rely on histological procedures. Here, we describe our non-invasive method utilizing synchrotron X-ray computed microtomography for the examination of growth plate bridging, which ultimately leads to its closure coincident with termination of further longitudinal bone growth. We then apply this method to a dataset obtained from a benchtop micro computed tomography scanner to highlight its potential for wide usage. Furthermore, we conduct finite element modeling at the micron-scale to reveal the effects of growth plate bridging on local tissue mechanics. Employment of these 3D analyses of growth plate bone bridging is likely to advance our understanding of the physiological mechanisms that control growth plate fusion.
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Affiliation(s)
- Katherine A. Staines
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom
| | - Kamel Madi
- School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Behzad Javaheri
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Peter D. Lee
- School of Materials, The University of Manchester, Manchester, United Kingdom
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47
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Javaheri B, Poulet B, Aljazzar A, de Souza R, Piles M, Hopkinson M, Shervill E, Pollard A, Chan B, Chang YM, Orriss IR, Lee PD, Pitsillides AA. Stable sulforaphane protects against gait anomalies and modifies bone microarchitecture in the spontaneous STR/Ort model of osteoarthritis. Bone 2017; 103:308-317. [PMID: 28778596 PMCID: PMC5571892 DOI: 10.1016/j.bone.2017.07.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/22/2022]
Abstract
Osteoarthritis (OA), affecting joints and bone, causes physical gait disability with huge socio-economic burden; treatment remains palliative. Roles for antioxidants in protecting against such chronic disorders have been examined previously. Sulforaphane is a naturally occurring antioxidant. Herein, we explore whether SFX-01®, a stable synthetic form of sulforaphane, modifies gait, bone architecture and slows/reverses articular cartilage destruction in a spontaneous OA model in STR/Ort mice. Sixteen mice (n=8/group) were orally treated for 3months with either 100mg/kg SFX-01® or vehicle. Gait was recorded, tibiae were microCT scanned and analysed. OA lesion severity was graded histologically. The effect of SFX-01® on bone turnover markers in vivo was complemented by in vitro bone formation and resorption assays. Analysis revealed development of OA-related gait asymmetry in vehicle-treated STR/Ort mice, which did not emerge in SFX-01®-treated mice. We found significant improvements in trabecular and cortical bone. Despite these marked improvements, we found that histologically-graded OA severity in articular cartilage was unmodified in treated mice. These changes are also reflected in anabolic and anti-catabolic actions of SFX-01® treatment as reflected by alteration in serum markers as well as changes in primary osteoblast and osteoclast-like cells in vitro. We report that SFX-01® improves bone microarchitecture in vivo, produces corresponding changes in bone cell behaviour in vitro and leads to greater symmetry in gait, without marked effects on cartilage lesion severity in STR/Ort osteoarthritic mice. Our findings support both osteotrophic roles and novel beneficial gait effects for SFX-01® in this model of spontaneous OA.
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Affiliation(s)
- Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.
| | - Blandine Poulet
- Institute of Ageing and Chronic Disease, University of Liverpool, West Derby Street, Liverpool L7 8TX, UK
| | - Ahmed Aljazzar
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Roberto de Souza
- Universidade Federal de Mato Grosso (UFMT), Departamento de Clínica, Cuiabá, Brazil
| | - Miriam Piles
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Mark Hopkinson
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Elaine Shervill
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Andrea Pollard
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Boris Chan
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Yu-Mei Chang
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Isabel R Orriss
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Peter D Lee
- Manchester X-Ray Imaging Facility, University of Manchester, Manchester, UK
| | - Andrew A Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
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48
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Mosey H, Núñez JA, Goring A, Clarkin CE, Staines KA, Lee PD, Pitsillides AA, Javaheri B. Sost Deficiency does not Alter Bone's Lacunar or Vascular Porosity in Mice. Front Mater 2017; 4:27. [PMID: 29349060 PMCID: PMC5769812 DOI: 10.3389/fmats.2017.00027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
SCLEROSTIN (Sost) is expressed predominantly in osteocytes acting as a negative regulator of bone formation. In humans, mutations in the SOST gene lead to skeletal overgrowth and increased bone mineral density, suggesting that SCLEROSTIN is a key regulator of bone mass. The function of SCLEROSTIN as an inhibitor of bone formation is further supported by Sost knockout (KO) mice which display a high bone mass with elevated bone formation. Previous studies have indicated that Sost exerts its effect on bone formation through Wnt-mediated regulation of osteoblast differentiation, proliferation, and activity. Recent in vitro studies have also suggested that SCLEROSTIN regulates angiogenesis and osteoblast-to-osteocyte transition. Despite this wealth of knowledge of the mechanisms responsible for SCLEROSTIN action, no previous studies have examined whether SCLEROSTIN regulates osteocyte and vascular configuration in cortices of mouse tibia. Herein, we image tibiae from Sost KO mice and their wild-type (WT) counterparts with high-resolution CT to examine whether lack of SCLEROSTIN influences the morphometric properties of lacunae and vascular canal porosity relating to osteocytes and vessels within cortical bone. Male Sost KO and WT mice (n = 6/group) were sacrificed at 12 weeks of age. Fixed tibiae were analyzed using microCT to examine cortical bone mass and architecture. Then, samples were imaged by using benchtop and synchrotron nano-computed tomography at the tibiofibular junction. Our data, consistent with previous studies show that, Sost deficiency leads to significant enhancement of bone mass by cortical thickening and bigger cross-sectional area and we find that this occurs without modifications of tibial ellipticity, a measure of bone shape. In addition, our data show that there are no significant differences in any lacunar or vascular morphometric or geometric parameters between Sost KO mouse tibia and WT counterparts. We, therefore, conclude that the significant increases in bone mass induced by Sost deficiency are not accompanied by any significant modification in the density, organization, or shape of osteocyte lacunae or vascular content within the cortical bone. These data may imply that SCLEROSTIN does not modify the frequency of osteocytogenic recruitment of osteoblasts to initiate terminal osteocytic differentiation in mice.
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Affiliation(s)
- Henry Mosey
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Juan A. Núñez
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Alice Goring
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Claire E. Clarkin
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Katherine A. Staines
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom
| | - Peter D. Lee
- Manchester X-Ray Imaging Facility, University of Manchester, Manchester, United Kingdom
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
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49
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Staines KA, Javaheri B, Hohenstein P, Fleming R, Ikpegbu E, Unger E, Hopkinson M, Buttle DJ, Pitsillides AA, Farquharson C. Hypomorphic conditional deletion of E11/Podoplanin reveals a role in osteocyte dendrite elongation. J Cell Physiol 2017; 232:3006-3019. [PMID: 28488815 PMCID: PMC5575468 DOI: 10.1002/jcp.25999] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/08/2017] [Indexed: 12/31/2022]
Abstract
The transmembrane glycoprotein E11/Podoplanin (Pdpn) has been implicated in the initial stages of osteocyte differentiation. However, its precise function and regulatory mechanisms are still unknown. Due to the known embryonic lethality induced by global Pdpn deletion, we have herein explored the effect of bone‐specific Pdpn knockdown on osteocyte form and function in the post‐natal mouse. Extensive skeletal phenotyping of male and female 6‐week‐old Oc‐cre;Pdpnflox/flox (cKO) mice and their Pdpnflox/flox controls (fl/fl) has revealed that Pdpn deletion significantly compromises tibial cortical bone microarchitecture in both sexes, albeit to different extents (p < 0.05). Consistent with this, we observed an increase in stiffness in female cKO mice in comparison to fl/fl mice (p < 0.01). Moreover, analysis of the osteocyte phenotype by phalloidin staining revealed a significant decrease in the dendrite volume (p < 0.001) and length (p < 0.001) in cKO mice in which deletion of Pdpn also modifies the bone anabolic loading response (p < 0.05) in comparison to age‐matched fl/fl mice. Together, these data confirm a regulatory role for Pdpn in osteocyte dendrite formation and as such, in the control of osteocyte function. As the osteocyte dendritic network is known to play vital roles in regulating bone modeling/remodeling, this highlights an essential role for Pdpn in bone homeostasis.
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Affiliation(s)
- Katherine A Staines
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK.,School of Applied Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh, UK
| | - Behzad Javaheri
- Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Peter Hohenstein
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK
| | - Robert Fleming
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK
| | - Ekele Ikpegbu
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK.,Michael Okpara University of Agriculture, Nigeria
| | - Erin Unger
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK
| | - Mark Hopkinson
- Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - David J Buttle
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | | | - Colin Farquharson
- Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, UK
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50
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Suswillo RFL, Javaheri B, Rawlinson SCF, Dowthwaite GP, Lanyon LE, Pitsillides AA. Corrigendum: Strain uses gap junctions to reverse stimulation of osteoblast proliferation by osteocytes. Cell Biochem Funct 2017; 35:244. [PMID: 28589681 PMCID: PMC6886053 DOI: 10.1002/cbf.3268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
| | - Behzad Javaheri
- Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Simon C F Rawlinson
- Institute of Dentistry, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Gary P Dowthwaite
- Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Lance E Lanyon
- School of Veterinary Sciences, University of Bristol, Bristol, UK
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