1
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Mukherjee J, Chaturvedi D, Mishra S, Jain R, Dandekar P. Microfluidic technology for cell biology-related applications: a review. J Biol Phys 2024; 50:1-27. [PMID: 38055086 PMCID: PMC10864244 DOI: 10.1007/s10867-023-09646-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 11/13/2023] [Indexed: 12/07/2023] Open
Abstract
Fluid flow at the microscale level exhibits a unique phenomenon that can be explored to fabricate microfluidic devices integrated with components that can perform various biological functions. In this manuscript, the importance of physics for microscale fluid dynamics using microfluidic devices has been reviewed. Microfluidic devices provide new opportunities with regard to spatial and temporal control over cell growth. Furthermore, the manuscript presents an overview of cellular stimuli observed by combining surfaces that mimic the complex biochemistries and different geometries of the extracellular matrix, with microfluidic channels regulating the transport of fluids, soluble factors, etc. We have also explained the concept of mechanotransduction, which defines the relation between mechanical force and biological response. Furthermore, the manipulation of cellular microenvironments by the use of microfluidic systems has been highlighted as a useful device for basic cell biology research activities. Finally, the article focuses on highly integrated microfluidic platforms that exhibit immense potential for biomedical and pharmaceutical research as robust and portable point-of-care diagnostic devices for the assessment of clinical samples.
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Affiliation(s)
- Joydeb Mukherjee
- Department of Biological Science and Biotechnology, Institute of Chemical Technology, Mumbai, 400019, India
| | - Deepa Chaturvedi
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Mumbai, 400019, India
| | - Shlok Mishra
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai, 400019, India
| | - Ratnesh Jain
- Department of Biological Science and Biotechnology, Institute of Chemical Technology, Mumbai, 400019, India
| | - Prajakta Dandekar
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Mumbai, 400019, India.
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2
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Sheng X, Xia Z, Yang H, Hu R. The ubiquitin codes in cellular stress responses. Protein Cell 2024; 15:157-190. [PMID: 37470788 PMCID: PMC10903993 DOI: 10.1093/procel/pwad045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/04/2023] [Indexed: 07/21/2023] Open
Abstract
Ubiquitination/ubiquitylation, one of the most fundamental post-translational modifications, regulates almost every critical cellular process in eukaryotes. Emerging evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses, from exogenous factors to cellular reactions, causing a dazzling variety of functional consequences. Various forms of ubiquitin signals generated by ubiquitylation events in specific milieus, known as ubiquitin codes, constitute an intrinsic part of myriad cellular stress responses. These ubiquitination events, leading to proteolytic turnover of the substrates or just switch in functionality, initiate, regulate, or supervise multiple cellular stress-associated responses, supporting adaptation, homeostasis recovery, and survival of the stressed cells. In this review, we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses, while discussing how stresses modulate the ubiquitin system. This review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.
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Affiliation(s)
- Xiangpeng Sheng
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- State Key Laboratory of Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Zhixiong Xia
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hanting Yang
- Department of Neurology, State Key Laboratory of Medical Neurobiology, Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Ronggui Hu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
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3
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Ristaniemi A, Šećerović A, Dischl V, Crivelli F, Heub S, Ledroit D, Weder G, Grad S, Ferguson SJ. Physiological and degenerative loading of bovine intervertebral disc in a bioreactor: A finite element study of complex motions. J Mech Behav Biomed Mater 2023; 143:105900. [PMID: 37201227 DOI: 10.1016/j.jmbbm.2023.105900] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 04/28/2023] [Accepted: 05/07/2023] [Indexed: 05/20/2023]
Abstract
Intervertebral disc (IVD) degeneration and regenerative therapies are commonly studied in organ-culture experiments with uniaxial compressive loading. Recently, in our laboratory, we established a bioreactor system capable of applying loads in six degrees-of-freedom (DOF) to bovine IVDs, which replicates more closely the complex multi-axial loading of the IVD in vivo. However, the magnitudes of loading that are physiological (able to maintain cell viability) or mechanically degenerative are unknown for load cases combining several DOFs. This study aimed to establish physiological and degenerative levels of maximum principal strains and stresses in the bovine IVD tissue and to investigate how they are achieved under complex load cases related to common daily activities. The physiological and degenerative levels of maximum principal strains and stresses were determined via finite element (FE) analysis of bovine IVD subjected to experimentally established physiological and degenerative compressive loading protocols. Then, complex load cases, such as a combination of compression + flexion + torsion, were applied on the FE-model with increasing magnitudes of loading to discover when physiological and degenerative tissue strains and stresses were reached. When applying 0.1 MPa of compression and ±2-3° of flexion and ±1-2° of torsion the investigated mechanical parameters remained at physiological levels, but with ±6-8° of flexion in combination with ±2-4° of torsion, the stresses in the outer annulus fibrosus (OAF) exceeded degenerative levels. In the case of compression + flexion + torsion, the mechanical degeneration likely initiates at the OAF when loading magnitudes are high enough. The physiological and degenerative magnitudes can be used as guidelines for bioreactor experiments with bovine IVDs.
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Affiliation(s)
| | | | - Vincent Dischl
- Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | - Francesco Crivelli
- CSEM, Swiss Center for Electronics and Microtechnology, Alpnach, Switzerland
| | - Sarah Heub
- CSEM, Swiss Center for Electronics and Microtechnology, Neuchâtel, Switzerland
| | - Diane Ledroit
- CSEM, Swiss Center for Electronics and Microtechnology, Neuchâtel, Switzerland
| | - Gilles Weder
- CSEM, Swiss Center for Electronics and Microtechnology, Neuchâtel, Switzerland
| | - Sibylle Grad
- AO Research Institute Davos, Davos, Switzerland; Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
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4
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Kourouklis AP, Wahlsten A, Stracuzzi A, Martyts A, Paganella LG, Labouesse C, Al-Nuaimi D, Giampietro C, Ehret AE, Tibbitt MW, Mazza E. Control of hydrostatic pressure and osmotic stress in 3D cell culture for mechanobiological studies. BIOMATERIALS ADVANCES 2023; 145:213241. [PMID: 36529095 DOI: 10.1016/j.bioadv.2022.213241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/25/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Hydrostatic pressure (HP) and osmotic stress (OS) play an important role in various biological processes, such as cell proliferation and differentiation. In contrast to canonical mechanical signals transmitted through the anchoring points of the cells with the extracellular matrix, the physical and molecular mechanisms that transduce HP and OS into cellular functions remain elusive. Three-dimensional cell cultures show great promise to replicate physiologically relevant signals in well-defined host bioreactors with the goal of shedding light on hidden aspects of the mechanobiology of HP and OS. This review starts by introducing prevalent mechanisms for the generation of HP and OS signals in biological tissues that are subject to pathophysiological mechanical loading. We then revisit various mechanisms in the mechanotransduction of HP and OS, and describe the current state of the art in bioreactors and biomaterials for the control of the corresponding physical signals.
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Affiliation(s)
- Andreas P Kourouklis
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland.
| | - Adam Wahlsten
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland
| | - Alberto Stracuzzi
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Anastasiya Martyts
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland
| | - Lorenza Garau Paganella
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Celine Labouesse
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Dunja Al-Nuaimi
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland
| | - Costanza Giampietro
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Alexander E Ehret
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Mark W Tibbitt
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland
| | - Edoardo Mazza
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
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5
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Diwan AD, Melrose J. Intervertebral disc degeneration and how it leads to low back pain. JOR Spine 2022; 6:e1231. [PMID: 36994466 PMCID: PMC10041390 DOI: 10.1002/jsp2.1231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 09/23/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
The purpose of this review was to evaluate data generated by animal models of intervertebral disc (IVD) degeneration published in the last decade and show how this has made invaluable contributions to the identification of molecular events occurring in and contributing to pain generation. IVD degeneration and associated spinal pain is a complex multifactorial process, its complexity poses difficulties in the selection of the most appropriate therapeutic target to focus on of many potential candidates in the formulation of strategies to alleviate pain perception and to effect disc repair and regeneration and the prevention of associated neuropathic and nociceptive pain. Nerve ingrowth and increased numbers of nociceptors and mechanoreceptors in the degenerate IVD are mechanically stimulated in the biomechanically incompetent abnormally loaded degenerate IVD leading to increased generation of low back pain. Maintenance of a healthy IVD is, thus, an important preventative measure that warrants further investigation to preclude the generation of low back pain. Recent studies with growth and differentiation factor 6 in IVD puncture and multi-level IVD degeneration models and a rat xenograft radiculopathy pain model have shown it has considerable potential in the prevention of further deterioration in degenerate IVDs, has regenerative properties that promote recovery of normal IVD architectural functional organization and inhibits the generation of inflammatory mediators that lead to disc degeneration and the generation of low back pain. Human clinical trials are warranted and eagerly anticipated with this compound to assess its efficacy in the treatment of IVD degeneration and the prevention of the generation of low back pain.
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Affiliation(s)
- Ashish D. Diwan
- Spine Service, Department of Orthopaedic Surgery, St. George & Sutherland Clinical School University of New South Wales Sydney New South Wales Australia
| | - James Melrose
- Raymond Purves Bone and Joint Research Laboratory Kolling Institute, Sydney University Faculty of Medicine and Health, Northern Sydney Area Health District, Royal North Shore Hospital Sydney New South Wales Australia
- Graduate School of Biomedical Engineering The University of New South Wales Sydney New South Wales Australia
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6
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The Influence of Intervertebral Disc Microenvironment on the Biological Behavior of Engrafted Mesenchymal Stem Cells. Stem Cells Int 2022; 2022:8671482. [DOI: 10.1155/2022/8671482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/19/2022] [Accepted: 10/25/2022] [Indexed: 11/09/2022] Open
Abstract
Intervertebral disc degeneration is the main cause of low back pain. Traditional treatment methods cannot repair degenerated intervertebral disc tissue. The emergence of stem cell therapy makes it possible to regenerate and repair degenerated intervertebral disc tissue. At present, mesenchymal stem cells are the most studied, and different types of mesenchymal stem cells have their own characteristics. However, due to the harsh and complex internal microenvironment of the intervertebral disc, it will affect the biological behaviors of the implanted mesenchymal stem cells, such as viability, proliferation, migration, and chondrogenic differentiation, thereby affecting the therapeutic effect. This review is aimed at summarizing the influence of each intervertebral disc microenvironmental factor on the biological behavior of mesenchymal stem cells, so as to provide new ideas for using tissue engineering technology to assist stem cells to overcome the influence of the microenvironment in the future.
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7
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Zhang Y, Yao L, Robinson KM, Dillingham TR. Biomarkers in the Degenerative Human Intervertebral Disc Tissue and Blood. Am J Phys Med Rehabil 2022; 101:983-987. [PMID: 34954738 PMCID: PMC9209568 DOI: 10.1097/phm.0000000000001943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
ABSTRACT Patients with back pain comprise a large proportion of the outpatient practice among physiatrists. Diagnostic tools are limited to clinical history, physical examinations, and imaging. Nonsurgical treatments are largely empirical, encompassing medications, physical therapy, manual treatments, and interventional spinal procedures. A body of literature is emerging confirming elevated levels of biomarkers including inflammatory cytokines in patients with back pain and/or radiculopathy, largely because the protein assay sensitivity has increased. These biomarkers may serve as tools to assist diagnosis and assess outcomes.The presence of inflammatory mediators in the intervertebral disc tissues and blood helped to confirm the inflammatory underpinnings of back pain related to intervertebral disc degeneration. Literature reviewed here suggests that biomarkers could assist clinical diagnosis and monitor physiological outcomes during and after treatments for spine-related pain. Biomarkers must be measured in a large and diverse asymptomatic population, in the context of age and comorbidities to prevent false-positive tests. These levels can then be rationally compared with those in patients with back disorders including discogenic back pain, radiculopathy, and spinal stenosis. While studies reviewed here used "candidate marker" approaches, future nonbiased approaches in clearly defined patient populations could uncover novel biomarkers in clinical management of patients.
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Affiliation(s)
- Yejia Zhang
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania
- Rehabilitation Medicine Service, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA
| | - Lutian Yao
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania
| | - Keith M Robinson
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania
- Rehabilitation Medicine Service, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA
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8
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Jimenez V, Miranda K, Augusto I. The old and the new about the contractile vacuole of Trypanosoma cruzi. J Eukaryot Microbiol 2022; 69:e12939. [PMID: 35916682 DOI: 10.1111/jeu.12939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 11/28/2022]
Abstract
Osmoregulation is a conserved cellular process required for the survival of all organisms. In protists, the need for robust compensatory mechanisms that can maintain cell volume and tonicity within physiological range is even more relevant, as their life cycles are often completed in different environments. Trypanosoma cruzi, the protozoan pathogen responsible for Chagas disease, is transmitted by an insect vector to multiple types of mammalian hosts. The contractile vacuole complex (CVC) is an organelle that senses and compensates osmotic changes in the parasites, ensuring their survival upon ionic and osmotic challenges. Recent work shows that the contractile vacuole is also a key component of the secretory and endocytic pathways, regulating the selective targeting of surface proteins during differentiation. Here we summarize our current knowledge of the mechanisms involved in the osmoregulatory processes that take place in the vacuole, and we explore the new and exciting functions of this organelle in cell trafficking and signaling.
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Affiliation(s)
- Veronica Jimenez
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton
| | - Kildare Miranda
- Laboratorio de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro.,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Brazil
| | - Ingrid Augusto
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton.,Laboratorio de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro
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9
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Bermudez-Lekerika P, Crump KB, Tseranidou S, Nüesch A, Kanelis E, Alminnawi A, Baumgartner L, Muñoz-Moya E, Compte R, Gualdi F, Alexopoulos LG, Geris L, Wuertz-Kozak K, Le Maitre CL, Noailly J, Gantenbein B. Immuno-Modulatory Effects of Intervertebral Disc Cells. Front Cell Dev Biol 2022; 10:924692. [PMID: 35846355 PMCID: PMC9277224 DOI: 10.3389/fcell.2022.924692] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/20/2022] [Indexed: 11/29/2022] Open
Abstract
Low back pain is a highly prevalent, chronic, and costly medical condition predominantly triggered by intervertebral disc degeneration (IDD). IDD is often caused by structural and biochemical changes in intervertebral discs (IVD) that prompt a pathologic shift from an anabolic to catabolic state, affecting extracellular matrix (ECM) production, enzyme generation, cytokine and chemokine production, neurotrophic and angiogenic factor production. The IVD is an immune-privileged organ. However, during degeneration immune cells and inflammatory factors can infiltrate through defects in the cartilage endplate and annulus fibrosus fissures, further accelerating the catabolic environment. Remarkably, though, catabolic ECM disruption also occurs in the absence of immune cell infiltration, largely due to native disc cell production of catabolic enzymes and cytokines. An unbalanced metabolism could be induced by many different factors, including a harsh microenvironment, biomechanical cues, genetics, and infection. The complex, multifactorial nature of IDD brings the challenge of identifying key factors which initiate the degenerative cascade, eventually leading to back pain. These factors are often investigated through methods including animal models, 3D cell culture, bioreactors, and computational models. However, the crosstalk between the IVD, immune system, and shifted metabolism is frequently misconstrued, often with the assumption that the presence of cytokines and chemokines is synonymous to inflammation or an immune response, which is not true for the intact disc. Therefore, this review will tackle immunomodulatory and IVD cell roles in IDD, clarifying the differences between cellular involvements and implications for therapeutic development and assessing models used to explore inflammatory or catabolic IVD environments.
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Affiliation(s)
- Paola Bermudez-Lekerika
- Tissue Engineering for Orthopaedics and Mechanobiology, Bone and Joint Program, Department for BioMedical Research (DBMR), Faculty of Medicine, University of Bern, Bern, Switzerland.,Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, Medical Faculty, University of Bern, Bern, Switzerland
| | - Katherine B Crump
- Tissue Engineering for Orthopaedics and Mechanobiology, Bone and Joint Program, Department for BioMedical Research (DBMR), Faculty of Medicine, University of Bern, Bern, Switzerland.,Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, Medical Faculty, University of Bern, Bern, Switzerland
| | | | - Andrea Nüesch
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Exarchos Kanelis
- ProtATonce Ltd., Athens, Greece.,School of Mechanical Engineering, National Technical University of Athens, Zografou, Greece
| | - Ahmad Alminnawi
- GIGA In Silico Medicine, University of Liège, Liège, Belgium.,Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium
| | | | | | - Roger Compte
- Twin Research and Genetic Epidemiology, St Thomas' Hospital, King's College London, London, United Kingdom
| | - Francesco Gualdi
- Institut Hospital Del Mar D'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Leonidas G Alexopoulos
- ProtATonce Ltd., Athens, Greece.,School of Mechanical Engineering, National Technical University of Athens, Zografou, Greece
| | - Liesbet Geris
- GIGA In Silico Medicine, University of Liège, Liège, Belgium.,Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium.,Biomechanics Research Unit, KU Leuven, Leuven, Belgium
| | - Karin Wuertz-Kozak
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, United States.,Spine Center, Schön Klinik München Harlaching Academic Teaching Hospital and Spine Research Institute of the Paracelsus Private Medical University Salzburg (Austria), Munich, Germany
| | - Christine L Le Maitre
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | | | - Benjamin Gantenbein
- Tissue Engineering for Orthopaedics and Mechanobiology, Bone and Joint Program, Department for BioMedical Research (DBMR), Faculty of Medicine, University of Bern, Bern, Switzerland.,Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, Medical Faculty, University of Bern, Bern, Switzerland
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10
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Cheung CY, Huang TT, Chow N, Zhang S, Zhao Y, Chau MP, Chan WC, Wong CCL, Boassa D, Phan S, Ellisman MH, Yates JR, Xu S, Yu Z, Zhang Y, Zhang R, Ng LL, Ko BCB. Unconventional tonicity-regulated nuclear trafficking of NFAT5 mediated by KPNB1, XPOT and RUVBL2. J Cell Sci 2022; 135:275560. [PMID: 35635291 PMCID: PMC9377714 DOI: 10.1242/jcs.259280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 05/20/2022] [Indexed: 11/20/2022] Open
Abstract
NFAT5 is the only known mammalian tonicity-responsive transcription factor with essential role in cellular adaptation to hypertonic stress. It is also implicated in diverse physiological and pathological processes. NFAT5 activity is tightly regulated by extracellular tonicity, but the underlying mechanisms remain elusive. We demonstrated that NFAT5 enters the nucleus via the nuclear pore complex. We found that NFAT5 utilizes a unique nuclear localization signal (NFAT5-NLS) for nuclear import. siRNA screening revealed that only karyopherin β1 (KPNB1), but not karyopherin alpha, is responsible for the nuclear import of NFAT5 via direct interaction with the NFAT5-NLS. Proteomics analysis and siRNA screening further revealed that nuclear export of NFAT5 under hypotonicity is driven by Exportin-T, where the process requires RuvB-Like AAA type ATPase 2 (RUVBL2) as an indispensable chaperone. Our findings have identified an unconventional tonicity-dependent nucleocytoplasmic trafficking pathway for NFAT5, a critical step in orchestrating rapid cellular adaptation to change in extracellular tonicity. These findings offer an opportunity for the development of novel NFAT5 targeting strategies that are potentially useful for the treatment of diseases associated with NFAT5 dysregulation.
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Affiliation(s)
- Chris Y Cheung
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Ting-Ting Huang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Ning Chow
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Shuqi Zhang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yanxiang Zhao
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Mary P Chau
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Wing Cheung Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Catherine C L Wong
- Center for Precision Medicine Muti-Omics Research, Health Science Center, Peking University, China Clinical Laboratory Department, The Cancer Hospital of the University of Chinese Academy of Sciences, Beijing, China
| | - Daniela Boassa
- Department of Neurosciences, University of California, San Diego, USA.,Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, California, USA
| | - Sebastien Phan
- Department of Neurosciences, University of California, San Diego, USA.,Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, California, USA
| | - Mark H Ellisman
- Department of Neurosciences, University of California, San Diego, USA.,Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, California, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA
| | - SongXiao Xu
- The Clinical Laboratory Department, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer, Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Zicheng Yu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yajing Zhang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Rui Zhang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Ling Ling Ng
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
| | - Ben C B Ko
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hong Kong, China
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11
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Mainardi A, Cambria E, Occhetta P, Martin I, Barbero A, Schären S, Mehrkens A, Krupkova O. Intervertebral Disc-on-a-Chip as Advanced In Vitro Model for Mechanobiology Research and Drug Testing: A Review and Perspective. Front Bioeng Biotechnol 2022; 9:826867. [PMID: 35155416 PMCID: PMC8832503 DOI: 10.3389/fbioe.2021.826867] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 12/20/2021] [Indexed: 12/14/2022] Open
Abstract
Discogenic back pain is one of the most diffused musculoskeletal pathologies and a hurdle to a good quality of life for millions of people. Existing therapeutic options are exclusively directed at reducing symptoms, not at targeting the underlying, still poorly understood, degenerative processes. Common intervertebral disc (IVD) disease models still do not fully replicate the course of degenerative IVD disease. Advanced disease models that incorporate mechanical loading are needed to investigate pathological causes and processes, as well as to identify therapeutic targets. Organs-on-chip (OoC) are microfluidic-based devices that aim at recapitulating tissue functions in vitro by introducing key features of the tissue microenvironment (e.g., 3D architecture, soluble signals and mechanical conditioning). In this review we analyze and depict existing OoC platforms used to investigate pathological alterations of IVD cells/tissues and discuss their benefits and limitations. Starting from the consideration that mechanobiology plays a pivotal role in both IVD homeostasis and degeneration, we then focus on OoC settings enabling to recapitulate physiological or aberrant mechanical loading, in conjunction with other relevant features (such as inflammation). Finally, we propose our view on design criteria for IVD-on-a-chip systems, offering a future perspective to model IVD mechanobiology.
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Affiliation(s)
- Andrea Mainardi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Elena Cambria
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Paola Occhetta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Ivan Martin
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Andrea Barbero
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Stefan Schären
- Spine Surgery, University Hospital Basel, Basel, Switzerland
| | - Arne Mehrkens
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
- Spine Surgery, University Hospital Basel, Basel, Switzerland
| | - Olga Krupkova
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
- Spine Surgery, University Hospital Basel, Basel, Switzerland
- Lepage Research Institute, University of Prešov, Prešov, Slovakia
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12
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Wimberly K, Choe KP. An extracellular matrix damage sensor signals through membrane-associated kinase DRL-1 to mediate cytoprotective responses in Caenorhabditis elegans. Genetics 2021; 220:6444994. [PMID: 34849856 DOI: 10.1093/genetics/iyab217] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
We and others previously identified circumferential bands of collagen named annular furrows as key components of a damage sensor in the cuticle of Caenorhabditis elegans that regulates cytoprotective genes. Mutation or loss of non-collagen secreted proteins OSM-7, OSM-8, and OSM-11 activate the same cytoprotective responses without obvious changes to the cuticle indicating that other extracellular proteins are involved. Here, we used RNAi screening to identify protein kinase DRL-1 as a key modulator of cytoprotective gene expression and stress resistance in furrow and extracellular OSM protein mutants. DRL-1 functions downstream from furrow disruption and is expressed in cells that induce cytoprotective genes. DRL-1 is not required for expression of cytoprotective genes under basal or oxidative stress conditions consistent with specificity to extracellular signals. DRL-1 was previously shown to regulate longevity via a 'Dietary Restriction-Like' state, but it functions downstream from furrow disruption by a distinct mechanism. The kinase domain of DRL-1 is related to mammalian MEKK3, and MEKK3 is recruited to a plasma membrane osmosensor complex by a scaffold protein. In C. elegans, DRL-1 contains an atypical hydrophobic C-terminus with predicted transmembrane domains and is constitutively expressed at or near the plasma membrane where it could function to receive extracellular damage signals for cells that mount cytoprotective responses.
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Affiliation(s)
- Keon Wimberly
- Department of Biology and Genetics Institute, University of Florida, Gainesville, FL 32611, USA
| | - Keith P Choe
- Department of Biology and Genetics Institute, University of Florida, Gainesville, FL 32611, USA
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13
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Lee J, Lee J, Lee S, Yoo SA, Kim KM, Kim WU, Cho CS, Yoon CH. Genetic deficiency of nuclear factor of activated T cells 5 attenuates the development of osteoarthritis in mice. Joint Bone Spine 2021; 89:105273. [PMID: 34537377 DOI: 10.1016/j.jbspin.2021.105273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study is aimed to investigate the role of nuclear factor of activated T cells 5 (NFAT5), originally known as the osmosensitive mammalian transcription factor, in the pathogenesis of osteoarthritis (OA) in mice. METHODS OA was induced in male C57BL/6 (wild-type) and NFAT5 haplo-insufficient (NFAT5+/-) mice via destabilization of the medial meniscus (DMM) surgery. OA severity and synovial inflammation were histologically assessed. Expression of CCL2, inflammatory cytokines, cartilage degrading enzymes was determined in the knee joints and cultured chondrocytes from wild-type and NFAT5+/- mice. RESULTS NFAT5 expression was significantly upregulated in the knee joint of a mouse after DMM surgery. NFAT5 deficiency decreased the severity of synovial inflammation and osteoarthritic changes in cartilage and subchondral bone. Moreover, NFAT5 deficiency also decreased the expression of CCL2, IL-1β, MMP-13, ADMATS-5, and macrophage infiltration in the joint. In cultured chondrocytes, hyperosmolar or IL-1β stimulation significantly enhanced the expression of NFAT5, CCL2, IL-1β, IL-6, and MMP-13, and this effect was abolished in chondrocytes from NFAT5+/- mice. Hyperosmolarity or IL-1β-induced NFAT5 and CCL2 downregulated by inhibiting p38 MAPK, JNK, and ERK pathways. CONCLUSIONS Our results indicate that NFAT5 is a crucial regulator of OA pathogenesis by upregulating CCL2 expression and macrophage recruitment. In chondrocyte, NFAT5 plays an important role in the response to hyperosmolar or IL-1β stimulation. Thus, NFAT5 could be an attractive therapeutic target for OA treatment.
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Affiliation(s)
- Jinhee Lee
- Division of Rheumatology, Department of Internal Medicine, The Catholic University of Korea, Seoul, 06591, Korea
| | - Jongmin Lee
- Division of Rheumatology, Department of Internal Medicine, The Catholic University of Korea, Seoul, 06591, Korea
| | - Saseong Lee
- Center for Integrative Rheumatoid Transcriptomics and Dynamics, The Catholic University of Korea, Seoul, 06591, Korea
| | - Seung-Ah Yoo
- Center for Integrative Rheumatoid Transcriptomics and Dynamics, The Catholic University of Korea, Seoul, 06591, Korea
| | - Ki-Myo Kim
- Center for Integrative Rheumatoid Transcriptomics and Dynamics, The Catholic University of Korea, Seoul, 06591, Korea
| | - Wan-Uk Kim
- Division of Rheumatology, Department of Internal Medicine, The Catholic University of Korea, Seoul, 06591, Korea; Center for Integrative Rheumatoid Transcriptomics and Dynamics, The Catholic University of Korea, Seoul, 06591, Korea
| | - Chul-Soo Cho
- Division of Rheumatology, Department of Internal Medicine, The Catholic University of Korea, Seoul, 06591, Korea
| | - Chong-Hyeon Yoon
- Division of Rheumatology, Department of Internal Medicine, The Catholic University of Korea, Seoul, 06591, Korea.
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14
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Wu X, Liu Y, Du J, Li X, Lin J, Ni L, Zhu P, Zhou H, Kong F, Yang H, Geng D, Mao H. Melatonin Attenuates Intervertebral Disk Degeneration via Maintaining Cartilaginous Endplate Integrity in Rats. Front Physiol 2021; 12:672572. [PMID: 34220535 PMCID: PMC8248798 DOI: 10.3389/fphys.2021.672572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/10/2021] [Indexed: 01/08/2023] Open
Abstract
Objective The aim of this study is to verify whether melatonin (Mel) could mitigate intervertebral disk degeneration (IVDD) in rats and to investigate the potential mechanism of it. Method A rat acupuncture model of IVDD was established with intraperitoneal injection of Mel. The effect of Mel on IVDD was analyzed via radiologic and histological evaluations. The specific Mel receptors were investigated in both the nucleus pulposus (NP) and cartilaginous endplates (EPs). In vitro, EP cartilaginous cells (EPCs) were treated by different concentrations of Mel under lipopolysaccharide (LPS) and Luzindole conditions. In addition, LPS-induced inflammatory response and matrix degradation following nuclear factor kappa-B (NF-κB) pathway activation were investigated to confirm the potential mechanism of Mel on EPCs. Results The percent disk height index (%DHI) and MRI signal decreased after initial puncture in the degeneration group compared with the control group, while Mel treatment protected disk height from decline and prevented the loss of water during the degeneration process. In the meantime, the histological staining of the Mel groups showed more integrity and well-ordered construction of the NP and EPs in both low and high concentration than that of the degeneration group. In addition, more deep-brown staining of type II collagen (Coll-II) was shown in the Mel groups compared with the degeneration group. Furthermore, in rat samples, immunohistochemical staining showed more positive cells of Mel receptors 1a and 1b in the EPs, instead of in the NP. Moreover, evident osteochondral lacuna formation was observed in rat EPs in the degeneration group; after Mel treatment, the osteochondral destruction alleviated accompanying fewer receptor activator for nuclear factor-κB ligand (RANKL) and tartrate-resistant acid phosphatase (TRAP)-stained positive cells expressed in the EPs. In vitro, Mel could promote the proliferation of EPCs, which protected EPCs from degeneration under LPS treatment. What is more, Mel downregulated the inflammatory response and matrix degradation of EPCs activated by NF-κB pathway through binding to its specific receptors. Conclusion These results indicate that Mel protects the integrity of the EPs and attenuates IVDD by binding to the Mel receptors in the EPs. It may alleviate the inflammatory response and matrix degradation of EPCs activated by NF-κB pathway.
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Affiliation(s)
- Xiexing Wu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yijie Liu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jiacheng Du
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaoping Li
- Department of Clinical Education, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jiayi Lin
- Department of Orthopedics Center, Ningbo No. 2 Hospital, Ningbo, China
| | - Li Ni
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Pengfei Zhu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hong Zhou
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Fanchen Kong
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Huilin Yang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Dechun Geng
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Haiqing Mao
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China
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15
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The TLR-2/TonEBP signaling pathway regulates 29-kDa fibronectin fragment-dependent expression of matrix metalloproteinases. Sci Rep 2021; 11:8891. [PMID: 33903620 PMCID: PMC8076285 DOI: 10.1038/s41598-021-87813-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
Tonicity-responsive enhancer-binding protein (TonEBP; nuclear factor of activated T cells 5) is a transcription factor that responds to changes in osmolality. However, recent studies have shown that it also modulates immune responses under inflammatory conditions independently of hyperosmolality. Fibronectin fragments (FN-fs), which are abundant in the synovial fluid of patients with osteoarthritis (OA), induce expression of matrix metalloproteinases (MMPs) via the toll-like receptor-2 (TLR-2) signaling pathway. In this study we examined whether TonEBP is involved in 29-kDa FN-f-induced expression of MMPs. The expression of TonEBP was significantly higher in human osteoarthritis compared with normal cartilage samples. 29-kDa FN-f affected the expression of MMPs 1, 3, and 13 via TonEBP, and expression and nuclear accumulation of TonEBP were induced by activation of the phospholipase C/NF-κB/MAPK signaling pathway and, in particular, modulated by TLR-2. In addition, 29-kDa FN-f induced the expression of osmoregulatory genes, including Tau-T, SMIT, and AR, as well as voltage-dependent calcium channels via the TonEBP/TLR-2 signaling pathway. These results show that 29-kDa FN-f upregulates MMPs in chondrocytes via the TLR-2/TonEBP signaling pathway.
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16
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Snuggs JW, Tessier S, Bunning RAB, Shapiro IM, Risbud MV, Le Maitre CL. TonEBP regulates the hyperosmotic expression of aquaporin 1 and 5 in the intervertebral disc. Sci Rep 2021; 11:3164. [PMID: 33542263 PMCID: PMC7862284 DOI: 10.1038/s41598-021-81838-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/22/2020] [Indexed: 01/30/2023] Open
Abstract
The central region of the intervertebral disc (IVD) is rich in proteoglycans, leading to a hyperosmotic environment, which fluctuates with daily loading. The cells of the nucleus pulposus (NP cells) have adapted to this environment via the function of tonicity enhancer binding protein (TonEBP), and NP cells have been shown to express several water channels known as aquaporins (AQP). We have previously shown that AQP1 and 5 decrease during IVD degeneration. Here, the regulation of AQP1 and 5 by hyperosmotic conditions and the role of TonEBP in this regulation was investigated. AQP1 and 5 gene expression was upregulated by hyperosmotic conditions mimicking the osmolality of the healthy IVD, which was abrogated by TonEBP knockdown. Furthermore, AQP1 and 5 immunopositivity was significantly reduced in TonEBPΔ/Δ E17.5 mice when compared with wildtype controls, indicating in vivo expression of AQP1 and 5 is controlled at least in part by TonEBP. This hyperosmotic regulation of AQP1 and 5 could help to explain the decreased AQP1 and 5 expression during degeneration, when the osmolality of the NP decreases. Together this data suggests that TonEBP-regulated osmo-adaptation may be disrupted during IVD degeneration when the expression of both AQPs is reduced.
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Affiliation(s)
- J. W. Snuggs
- grid.5884.10000 0001 0303 540XBiomolecular Sciences Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB UK
| | - S. Tessier
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA USA
| | - R. A. B. Bunning
- grid.5884.10000 0001 0303 540XBiomolecular Sciences Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB UK
| | - I. M. Shapiro
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, PA USA
| | - M. V. Risbud
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, PA USA
| | - C. L. Le Maitre
- grid.5884.10000 0001 0303 540XBiomolecular Sciences Research Centre, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB UK
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17
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Baumgartner L, Wuertz-Kozak K, Le Maitre CL, Wignall F, Richardson SM, Hoyland J, Ruiz Wills C, González Ballester MA, Neidlin M, Alexopoulos LG, Noailly J. Multiscale Regulation of the Intervertebral Disc: Achievements in Experimental, In Silico, and Regenerative Research. Int J Mol Sci 2021; 22:E703. [PMID: 33445782 PMCID: PMC7828304 DOI: 10.3390/ijms22020703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022] Open
Abstract
Intervertebral disc (IVD) degeneration is a major risk factor of low back pain. It is defined by a progressive loss of the IVD structure and functionality, leading to severe impairments with restricted treatment options due to the highly demanding mechanical exposure of the IVD. Degenerative changes in the IVD usually increase with age but at an accelerated rate in some individuals. To understand the initiation and progression of this disease, it is crucial to identify key top-down and bottom-up regulations' processes, across the cell, tissue, and organ levels, in health and disease. Owing to unremitting investigation of experimental research, the comprehension of detailed cell signaling pathways and their effect on matrix turnover significantly rose. Likewise, in silico research substantially contributed to a holistic understanding of spatiotemporal effects and complex, multifactorial interactions within the IVD. Together with important achievements in the research of biomaterials, manifold promising approaches for regenerative treatment options were presented over the last years. This review provides an integrative analysis of the current knowledge about (1) the multiscale function and regulation of the IVD in health and disease, (2) the possible regenerative strategies, and (3) the in silico models that shall eventually support the development of advanced therapies.
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Affiliation(s)
- Laura Baumgartner
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
| | - Karin Wuertz-Kozak
- Department of Biomedical Engineering, Rochester Institute of Technology (RIT), Rochester, NY 14623, USA;
- Schön Clinic Munich Harlaching, Spine Center, Academic Teaching Hospital and Spine Research Institute of the Paracelsus Medical University Salzburg (Austria), 81547 Munich, Germany
| | - Christine L. Le Maitre
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, UK;
| | - Francis Wignall
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Stephen M. Richardson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Judith Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Carlos Ruiz Wills
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
| | - Miguel A. González Ballester
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
- Catalan Institution for Research and Advanced Studies (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain
| | - Michael Neidlin
- Department of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece; (M.N.); (L.G.A.)
| | - Leonidas G. Alexopoulos
- Department of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece; (M.N.); (L.G.A.)
| | - Jérôme Noailly
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
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18
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Zhang Y, Wang Y, Zhou X, Wang J, Shi M, Wang J, Li F, Chen Q. Osmolarity controls the differentiation of adipose-derived stem cells into nucleus pulposus cells via histone demethylase KDM4B. Mol Cell Biochem 2020; 472:157-171. [PMID: 32594337 DOI: 10.1007/s11010-020-03794-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/13/2020] [Indexed: 12/25/2022]
Abstract
Adipose-derived stem cells (ADSCs) are an ideal source of cells for intervertebral disc (IVD) regeneration, but the effect of an increased osmotic microenvironment on ADSC differentiation remains unclear. Here, we aimed to elucidate whether hyperosmolarity facilitates ADSC nucleus pulposus (NP)-like differentiation and whether histone demethylase KDM4B is involved in this process. ADSCs were cultured under standard and increased osmolarity conditions for 1-3 weeks, followed by analysis for proliferation and viability. Differentiation was then quantified by gene and protein analysis. Finally, KDM4B knockdown ADSCs were generated using lentiviral vectors. The results showed that increasing the osmolarity of the differentiation medium to 400 mOsm significantly increased NP-like gene expression and the synthesis of extracellular matrix (ECM) components during ADSC differentiation; however, further increasing the osmolarity to 500 mOsm suppressed the NP-like differentiation of ADSCs. KDM4B, as well as the IVD formation regulators forkhead box (Fox)a1/2 and sonic hedgehog (Shh), were found to be significantly upregulated at 400 mOsm. KDM4B knockdown reduced Foxa1/2, Shh, and NP-associated markers' expression, as well as the synthesis of ECM components. The reduction in NP-like differentiation caused by KDM4B knockdown was partially rescued by Purmorphamine, a specific agonist of Shh. Moreover, we found that KDM4B can directly bind to the promoter region of Foxa1/2 and decrease the content of H3K9me3/2. In conclusion, our results indicate that a potential optimal osmolarity window might exist for successful ADSC differentiation. KDM4B plays an essential role in regulating the osmolarity-induced NP-like differentiation of ADSCs by interacting with Foxa1/2-Shh signaling.
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Affiliation(s)
- Yujie Zhang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Yanyan Wang
- Department of Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, Zhejiang, China
| | - Xiaopeng Zhou
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Jingkai Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Mingmin Shi
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Jian Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Fangcai Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China.
| | - Qixin Chen
- Department of Orthopedic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China.
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19
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Guo Y, Meng Y, Liu H, Wang B, Ding C, Rong X, Yang Y, Hong Y. Acid-sensing ion channels mediate the degeneration of intervertebral disc via various pathways-A systematic review. Channels (Austin) 2020; 13:367-373. [PMID: 31526163 PMCID: PMC6768050 DOI: 10.1080/19336950.2019.1664038] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
To elucidate the pathological significance of acid-sensing ion channels (ASICs) in intervertebral disc degeneration (IVDD), the database of Medline, Web of Science, and EmBase were carefully screened. Search terms used in each database varied slightly to optimize results. Data relating to the correlation between ASICs and IVDD was systematically collected and integrated into the review. 11 basic science studies, containing the related information, were finally identified for inclusion. Intervertebral disc degeneration (IVDD) is a common disease in middle-aged and elderly people, which has a great impact on patients’ quality of life. Many research teams have attempted to elucidate the pathogenesis of this degenerative disease, and have made considerable progress. Acid-sensing ion channels (ASICs) were once reported to be able to regulate the apoptosis process of chondrocytes in joint cartilage, which has been transplanted into the IVDD-related research. ASIC1a functions as the mediator for cells in nucleus pulposus (NP) and endplate (EP), with whose activation the apoptosis process would be accelerated. Moreover, ASIC1a’s activation could also regulate the anabolism in chondrocytes of EP, facilitating the degeneration. ASIC3 would only promote the degeneration in NP, possibly via its pro-inflammatory effect. The distribution of ASICs in NP, EP, annulus fibrosus, and the particular functions of ASIC1a and ASIC3 remind us about the pathological significance of ASICs in IVDD, which could be a promising therapeutic target in future treatment for IVDD.
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Affiliation(s)
- Yingjun Guo
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Yang Meng
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Hao Liu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Beiyu Wang
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Chen Ding
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Xin Rong
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Yi Yang
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
| | - Ying Hong
- Department of Orthopedic Surgery, West China Hospital, Sichuan University , Chengdu , Sichuan Province , China
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20
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Sadowska A, Altinay B, Hitzl W, Ferguson SJ, Wuertz-Kozak K. Hypo-Osmotic Loading Induces Expression of IL-6 in Nucleus Pulposus Cells of the Intervertebral Disc Independent of TRPV4 and TRPM7. Front Pharmacol 2020; 11:952. [PMID: 32714187 PMCID: PMC7341822 DOI: 10.3389/fphar.2020.00952] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/11/2020] [Indexed: 12/19/2022] Open
Abstract
Painful intervertebral disc (IVD) degeneration is an age-related process characterized by reduced tissue osmolarity, increased catabolism of the extracellular matrix, and elevated levels of pro-inflammatory molecules. With the aging population and constantly rising treatment costs, it is of utmost importance to identify potential therapeutic targets and new pharmacological treatment strategies for low back pain. Transient receptor potential (TRP) channels are a family of Ca2+ permeable cell membrane receptors, which can be activated by multitude of stimuli and have recently emerged as contributors to joint disease, but were not investigated closer in the IVD. Based on the gene array screening, TRPC1, TRPM7, and TRPV4 were overall the most highly expressed TRP channels in bovine IVD cells. We demonstrated that TRPV4 gene expression was down-regulated in hypo-osmotic condition, whereas its Ca2+ flux increased. No significant differences in Ca2+ flux and gene expression were observed for TRPM7 between hypo- and iso-osmotic groups. Upon hypo-osmotic stimulation, we overall identified via RNA sequencing over 3,000 up- or down-regulated targets, from which we selected aggrecan, ADAMTS9, and IL-6 and investigated whether their altered gene expression is mediated through either the TRPV4 or TRPM7 channel, using specific activators and inhibitors (GSK1016790A/GSK2193874 for TRPV4 and Naltriben/NS8593 for TRPM7). GSK1016790A induced the expression of IL-6 under iso-osmotic condition, alike to hypo-osmotic stimulation alone, indicating that this effect might be TRPV4-mediated. However, using the TRPV4 blocker GSK2193874 failed to prevent the increase of IL-6 under hypo-osmotic condition. A treatment with TRPM7-activator did not cause significant changes in the gene expression of tested targets. In conclusion, while TRPV4 and TRPM7 are likely involved in osmosensing in the IVD, neither of them mediates hypo-osmotically-induced gene expression changes of aggrecan, ADAMTS9, and IL-6.
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Affiliation(s)
| | - Birsen Altinay
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Wolfgang Hitzl
- Research Office (Biostatistics), Paracelsus Medical University, Salzburg, Austria.,Department of Ophthalmology and Optometry, Paracelsus Medical University Salzburg, Salzburg, Austria.,Research Program Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University, Salzburg, Austria
| | | | - Karin Wuertz-Kozak
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.,Tissue Regeneration & Mechanobiology Lab, Department of Biomedical Engineering, Rochester Institute of Technology (RIT), Rochester, NY, United States.,Spine Center, Schön Clinic Munich Harlaching, Academic Teaching Hospital and Spine Research Institute of the Salzburg Paracelsus Medical University, Munich, Germany
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Yao W, Dai H, Dong P, Gui J. [Differential expression of transient receptor potential vanilloid receptor 4 protein in osteoarthritis and normal cartilages]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2020; 34:63-68. [PMID: 31939237 DOI: 10.7507/1002-1892.201903056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objective To investigate the differential expression of transient receptor potential vanilloid receptor 4 (TRPV4) protein in the osteoarthritis (OA) and normal cartilages, and explore the role of TRPV4 in the prevention and treatment of OA. Methods The cartilage tissues from the patients of knee OA (OA group) and femoral neck fracture (control group) were taken. In OA group, there were 6 males and 9 females; the age ranged from 55 to 78 years (mean, 69 years); the Kellgren-Lawrence (K-L) score was 3.0±0.8. In control group, there were 5 males and 10 females; the age ranged from 57 to 91 years (mean, 71 years). There was no significant difference in gender and age between the two groups ( P>0.05). Western blot, real-time fluorescence quantitative PCR, Masson staining, and immunohistochemical staining were used to detect the difference in protein and mRNA expressions of TRPV4 between the OA and normal cartilages. Then the relationship between the K-L score of OA and the rate of TRPV4-positive cells was analyzed. Results The relative expression of TRPV4 protein and mRNA in OA group were 0.454±0.199 and 2.951±1.200, which were higher than those in control group (0.165±0.074, 1.437±0.682). The difference in relative expression of TRPV4 protein was significant ( t=2.718, P=0.026). Histology observation showed that the chondrocytes arranged disorderly in OA group, the structure of extracellular matrix was abnormal, and the cartilage defect reached the deep layer. There were more TRPV4-positive cells in the degenerated tissue, and the rate of TRPV4-positive cells was 37.353%±13.496%. The chondrocytes were arranged well in control group, and the rate of TRPV4-positive cells was only 9.642%±3.284%. There was a significant difference between the two groups ( t=7.491, P=0.000). The rate of TRPV4-positive cells in OA group was positively correlated with the OA K-L score ( r=0.775, P=0.001). Conclusion The TRPV4 expression increased in OA cartilages that may contribute to the development of OA.
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Affiliation(s)
- Wangxiang Yao
- Department of Sports Medicine and Joint Surgery, the Affiliated Nanjing Hospital of Nanjing Medical University, Nanjing Jiangsu, 210000, P.R.China;Department of Orthopaedics, the Affiliated Hangzhou Hospital of Nanjing Medical University, Hangzhou Zhejiang, 310006, P.R.China
| | - Hanhao Dai
- Department of Sports Medicine and Joint Surgery, the Affiliated Nanjing Hospital of Nanjing Medical University, Nanjing Jiangsu, 210000, P.R.China
| | - Peilong Dong
- Department of Sports Medicine and Joint Surgery, the Affiliated Nanjing Hospital of Nanjing Medical University, Nanjing Jiangsu, 210000, P.R.China
| | - Jianchao Gui
- Department of Sports Medicine and Joint Surgery, the Affiliated Nanjing Hospital of Nanjing Medical University, Nanjing Jiangsu, 210000,
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22
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Pfannkuche JJ, Guo W, Cui S, Ma J, Lang G, Peroglio M, Richards RG, Alini M, Grad S, Li Z. Intervertebral disc organ culture for the investigation of disc pathology and regeneration - benefits, limitations, and future directions of bioreactors. Connect Tissue Res 2019; 61:304-321. [PMID: 31556329 DOI: 10.1080/03008207.2019.1665652] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Low back pain is the leading cause of disability worldwide and in many patients the source of pain can be attributed to pathological changes within the intervertebral disc (IVD). As present treatment options fail to address the underlying biological problem, novel therapies are currently subject to intense research. The physiologic IVD microenvironment features a highly complex interaction of biochemical and mechanical factors influencing cell metabolism and extracellular matrix turnover and is therefore difficult to simulate for research purposes on IVD pathology. The first whole organ culture models were not able to sufficiently replicate human in vivo conditions as mechanical loading, the predominant way of IVD nutrient supply and waste exchange, remained disregarded. To mimic the unique IVD niche more realistically, whole organ culture bioreactors have been developed, allowing for dynamic loading of IVDs and nutrient exchange. Recent advancements on bioreactor systems have facilitated whole organ culture of various IVDs for extended periods. IVD organ culture bioreactors have the potential to bridge the gap between in vitro and in vivo systems and thus may give valuable insights on IVD pathology and/or potential novel treatment approaches if the respective model is adjusted according to a well-defined research question. In this review, we outline the potential of currently utilized IVD bioreactor systems and present suggestions for further developments to more reliably investigate IVD biology and novel treatment approaches.
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Affiliation(s)
- Judith-Johanna Pfannkuche
- AO Research Institute Davos, Davos, Switzerland.,Department of Orthopedic and Trauma Surgery, University Medical Center Freiburg, Albert-Ludwigs University of Freiburg, Freiburg, Germany
| | - Wei Guo
- AO Research Institute Davos, Davos, Switzerland.,The first affiliated hospital of Sun Yat-sen University, Guangzhou, China
| | - Shangbin Cui
- AO Research Institute Davos, Davos, Switzerland.,The first affiliated hospital of Sun Yat-sen University, Guangzhou, China
| | - Junxuan Ma
- AO Research Institute Davos, Davos, Switzerland
| | - Gernot Lang
- Department of Orthopedic and Trauma Surgery, University Medical Center Freiburg, Albert-Ludwigs University of Freiburg, Freiburg, Germany
| | | | - R Geoff Richards
- AO Research Institute Davos, Davos, Switzerland.,Department of Orthopedic and Trauma Surgery, University Medical Center Freiburg, Albert-Ludwigs University of Freiburg, Freiburg, Germany
| | - Mauro Alini
- AO Research Institute Davos, Davos, Switzerland
| | | | - Zhen Li
- AO Research Institute Davos, Davos, Switzerland
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Hall AC. The Role of Chondrocyte Morphology and Volume in Controlling Phenotype-Implications for Osteoarthritis, Cartilage Repair, and Cartilage Engineering. Curr Rheumatol Rep 2019; 21:38. [PMID: 31203465 PMCID: PMC6571082 DOI: 10.1007/s11926-019-0837-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Articular chondrocytes are exclusively responsible for the turnover of the extracellular matrix (ECM) of hyaline cartilage. However, chondrocytes are phenotypically unstable and, if they de-differentiate into hypertrophic or fibroblastic forms, will produce a defective and weak matrix. Chondrocyte volume and morphology exert a strong influence over phenotype and a full appreciation of the factors controlling chondrocyte phenotype stability is central to understanding (a) the mechanisms underlying the cartilage failure in osteoarthritis (OA), (b) the rationale for hyaline cartilage repair, and (c) the strategies for improving the engineering of resilient cartilage. The focus of this review is on the factors involved in, and the importance of regulating, chondrocyte morphology and volume as key controllers of chondrocyte phenotype. RECENT FINDINGS The visualisation of fluorescently-labelled in situ chondrocytes within non-degenerate and mildly degenerate cartilage, by confocal scanning laser microscopy (CLSM) and imaging software, has identified the marked heterogeneity of chondrocyte volume and morphology. The presence of chondrocytes with cytoplasmic processes, increased volume, and clustering suggests important early changes to their phenotype. Results from experiments more closely aligned to the normal physico-chemical environment of in situ chondrocytes are emphasising the importance of understanding the factors controlling chondrocyte morphology and volume that ultimately affect phenotype. An appreciation of the importance of chondrocyte volume and morphology for controlling the chondrocyte phenotype is advancing at a rapid pace and holds particular promise for developing strategies for protecting the chondrocytes against deleterious changes and thereby maintaining healthy and resilient cartilage.
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Affiliation(s)
- Andrew C Hall
- Deanery of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, EH8 9XD, UK.
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