1
|
Ajmal I, Farooq MA, Abbas SQ, Shah J, Majid M, Jiang W. Isoprenaline and salbutamol inhibit pyroptosis and promote mitochondrial biogenesis in arthritic chondrocytes by downregulating β-arrestin and GRK2. Front Pharmacol 2022; 13:996321. [PMID: 36188601 PMCID: PMC9519065 DOI: 10.3389/fphar.2022.996321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
Rheumatoid arthritis and osteoarthritis overlap many molecular mechanisms of cartilage destruction. Wear and tear in cartilage is chondrocyte-mediated, where chondrocytes act both as effector and target cells. In current study, role of β2-AR was studied in chondrocytes both in vitro and in vivo. High grade inflammation in vitro and in vivo disease models led to decline in anti-inflammatory β2-AR signaling and use of β2-AR agonist attenuated arthritis symptoms. Detailed analysis in chondrocytes revealed that Isoprenaline (ISO) and Salbutamol (SBT) increased cell viability and relative Bcl-2 expression, meanwhile, decreased proteins levels of TNF-α, IL-6 and IL-8 in arthritic chondrocytes when compared with control, respectively. SBT preserved physiological concentration of antioxidant enzymes (CAT, POD, SOD and GSH) in cartilage homogenates and ISO inhibited IL-1β-mediated genotoxicity in arthritic chondrocytes. Moreover, β2-AR agonist increased mitochondrial biogenesis and proteoglycan biosynthesis by upregulating the gene expression of PGC1-α, NRF2 and COL2A1, Acan, respectively. ISO and SBT inhibited extracellular matrix (ECM) degradation by downregulating the gene expression of MMP1, MMP3, MMP9 and ADAMTS5 in vitro and in vivo study. In mechanism, β2-AR agonists decreased β-arrestin and GRK2 pathway, and as a result mice receiving SBT did not exhibit severe disease. Hence our data suggest β2-AR agonist administered at disease onset can inhibit receptor internalization by downregulating the expression of β-arrestin and GRK2 in chondrocytes.
Collapse
Affiliation(s)
- Iqra Ajmal
- Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Muhammad Asad Farooq
- Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Syed Qamar Abbas
- Department of Pharmacy, Sarhad University of Science and Technology, Peshawar, Pakistan
| | - Jaffer Shah
- Department of Health, New York, NY, United States
- *Correspondence: Jaffer Shah, ; Muhammad Majid, ; Wenzheng Jiang,
| | - Muhammad Majid
- Faculty of Pharmacy, Capital University of Science and Technology Islamabad, Islamabad, Pakistan
- *Correspondence: Jaffer Shah, ; Muhammad Majid, ; Wenzheng Jiang,
| | - Wenzheng Jiang
- Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, China
- *Correspondence: Jaffer Shah, ; Muhammad Majid, ; Wenzheng Jiang,
| |
Collapse
|
2
|
Chen D, Guo J, Li L. Catalpol promotes mitochondrial biogenesis in chondrocytes. Arch Physiol Biochem 2022; 128:802-808. [PMID: 32096418 DOI: 10.1080/13813455.2020.1727927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The chondrocyte mitochondrial dysfunction has been considered to be associated with the pathogenesis of joint diseases. Catalpol is an active traditional Chinese medicine ingredient named Di-Huang, which is used widely to treat different diseases. In this study, we found the addition of catalpol in chondrocytes induced the expression of crucial mitochondrial regulators, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor-1 (NRF1), and mitochondrial transcription factor A (TFAM). Catalpol promoted mitochondrial biogenesis, as revealed by the induction on the mitochondrial DNA/nuclear DNA (mtDNA/nDNA) and the expression of several mitochondrial genes including translocase of outer mitochondrial membrane 22 (Tomm22), translocase of outer mitochondrial membrane 70 (Tomm70), mitochondrial import inner membrane translocase subunit 50 (Timm50), NADH dehydrogenase [ubiquinone] iron-sulphur protein 3 (NDUFS3), adenosine triphosphate (ATP) synthase subunit D (ATP5d), and cytochrome B. Consequently, catalpol increased cytochrome c oxidase activity, the mitochondrial respiratory rate, and the extracellular ATP production, indicating that catalpol boosted mitochondrial function. Mechanistically, catalpol increased the activation of the cAMP-responsive element-binding protein (CREB), and the inhibition of CREB abolished catalpol-mediated promotion on mitochondrial biogenesis. In summary, this study demonstrated that catalpol has the potential to be used in the treatment of joint diseases.
Collapse
Affiliation(s)
- Dan Chen
- Department of Rehabilitation, Third Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Jing Guo
- Department of Rehabilitation, Third Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Longguang Li
- Department of Rehabilitation, Third Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning, China
| |
Collapse
|
3
|
Osteoblasts induce glucose-derived ATP perturbations in chondrocytes through noncontact communication. Acta Biochim Biophys Sin (Shanghai) 2022; 54:625-636. [PMID: 35593470 PMCID: PMC9828329 DOI: 10.3724/abbs.2022042] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cartilage and subchondral bone communicate with each other through material and signal exchanges. However, direct evidence provided by experimental studies on their interactions is insufficient. In the present study, we establish a noncontact co-culture model with a transwell chamber to explore the energetic perturbations in chondrocytes influenced by osteoblasts. Our results indicate that osteoblasts induce more ATP generation in chondrocytes through an energetic shift characterized by enhanced glycolysis and impaired mitochondrial tricarboxylic acid cycle. Enhanced glycolysis is shown by an increase of secreted lactate and the upregulation of glycolytic enzymes, including glucose-6-phosphate isomerase (Gpi), liver type ATP-dependent 6-phosphofructokinase (Pfkl), fructose-bisphosphate aldolase C (Aldoc), glyceraldehyde-3-phosphate dehydrogenase (Gapdh), triosephosphate isomerase (Tpi1), and phosphoglycerate kinase 1 (Pgk1). Impaired mitochondrial tricarboxylic acid cycle is characterized by the downregulation of cytoplasmic aspartate aminotransferase (Got1) and mitochondrial citrate synthase (Cs). Osteoblasts induce the activation of Akt and P38 signaling to mediate ATP perturbations in chondrocytes. This study may deepen our understanding of the maintenance of metabolic homeostasis in the bone-cartilage unit.
Collapse
|
4
|
Gomez-Contreras PC, Kluz PN, Hines MR, Coleman MC. Intersections Between Mitochondrial Metabolism and Redox Biology Mediate Posttraumatic Osteoarthritis. Curr Rheumatol Rep 2021; 23:32. [PMID: 33893892 DOI: 10.1007/s11926-021-00994-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2021] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW This review will cover foundational studies and recent findings that established key concepts for understanding the importance of redox biology to chondrocyte mitochondrial function and osteoarthritis pathophysiology after injury. RECENT FINDINGS Articular chondrocyte mitochondria can be protected with a wide variety of antioxidants that will be discussed within a framework suggested by classic studies. These agents not only underscore the importance of thiol metabolism and associated redox function for chondrocyte mitochondria but also suggest complex interactions with signal transduction pathways and other molecular features of osteoarthritis that require more thorough investigation. Emerging evidence also indicates that reductive stress could occur alongside oxidative stress. Recent studies have shed new light on historic paradoxes in chondrocyte redox and mitochondrial physiology, leading to the development of promising disease-modifying therapies for posttraumatic osteoarthritis.
Collapse
Affiliation(s)
| | - Paige N Kluz
- University of Iowa, 1182 Biomedical Laboratories, 500 Newton Road, Iowa City, 52242, USA
| | - Madeline R Hines
- University of Iowa, 1182 Biomedical Laboratories, 500 Newton Road, Iowa City, 52242, USA
| | - Mitchell C Coleman
- University of Iowa, 1182 Biomedical Laboratories, 500 Newton Road, Iowa City, 52242, USA.
| |
Collapse
|
5
|
Heywood HK, Lee DA. Bioenergetic reprogramming of articular chondrocytes by exposure to exogenous and endogenous reactive oxygen species and its role in the anabolic response to low oxygen. J Tissue Eng Regen Med 2016; 11:2286-2294. [PMID: 26799635 PMCID: PMC5172424 DOI: 10.1002/term.2126] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 10/20/2015] [Accepted: 11/06/2015] [Indexed: 12/17/2022]
Abstract
Monolayer culture is integral to many cell‐based cartilage repair strategies, but chondrocytes lose regenerative potential with increasing duration in vitro. This coincides with elevated reactive oxygen species (ROS) levels and a bioenergetic transformation characterized by increasing mitochondrial function. This study investigates ROS as stimuli for bioenergetic reprogramming and the effect of antioxidants on the propensity of chondrocytes to regenerate a cartilaginous matrix. Articular chondrocytes were cultured in monolayer under a 2% O2 atmosphere. Oxidative stress was increased using 50 μm H2O2 or a 20% O2 culture atmosphere, or decreased using the antioxidant N‐acetyl‐cysteine (NAC). Mitochondrial function was characterized using 200 nm Mitotracker green and an oxygen biosensor. After two population doublings ± NAC, chondrocytes were encapsulated in alginate beads (1 × 107 cells/ml) for an additional 10 days before DMB assay of glycosaminoglycan content. The beads were cultured under both 20% O2 and the more physiological 5% O2 condition. Chondrocytes expanded in 20% O2 exhibited elevated mitochondrial mass and functional capacity, which was partially mimicked by the exogenous ROS, H2O2. Oligomycin treatment revealed that the increased oxygen consumption was coupled to oxidative phosphorylation. NAC limited these markers of bioenergetic reprogramming during culture‐expansion with no significant effect on subsequent GAG production under 20% O2. However, NAC treatment in monolayer abolished the hypoxic induction of GAG in alginate beads. This supports the hypothesis of a causal relationship between exposure to ROS and acquired mitochondrial function in chondrocytes. Additionally, mitochondrial function may be required for the hypoxic induction of GAG synthesis by chondrocytes. © 2015 The Authors. Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- H K Heywood
- School of Engineering and Materials Science, Queen Mary University of London, UK
| | - D A Lee
- School of Engineering and Materials Science, Queen Mary University of London, UK
| |
Collapse
|
6
|
Rudys R, Denkovskij J, Kirdaitė G, Bagdonas S. Induction of protoporphyrin IX in patient-derived synoviocytes, cartilage explants and chondrons after application of 5-aminolevulinic acid or its methyl ester. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 141:228-34. [PMID: 25463671 DOI: 10.1016/j.jphotobiol.2014.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/27/2014] [Accepted: 10/04/2014] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To compare the accumulation of protoporphyrin IX between synoviocytes of patients with rheumatoid arthritis (RA) or osteoarthritis (OA) and cartilage explants (CE) as well as chondrons of patients with OA after the application of 5-aminolevulinic acid (ALA) or its methyl ester (ALA-Me). MATERIALS AND METHODS Samples of synovial and cartilage tissues were obtained from joint replacement surgeries. The accumulation of PpIX was determined by measuring fluorescence spectra from 2 × 10(5) synoviocytes or chondrons suspended in a glass tube or directly from CE surface after 2, 4, 8 and 24h of incubation with ALA or ALA-Me. RESULTS No differences were found between the average fluorescence intensity values of PpIX in synoviocytes of patients with RA and OA. These values were non-significantly higher after incubation with ALA in comparison with ALA-Me at almost all time points. The average fluorescence intensity of PpIX in CE and chondrons was about ten times lower than in synoviocytes. The presence of preparation of hyaluronic acid (HA) significantly enhanced PpIX induction in chondrons versus treatment only with ALA. CONCLUSIONS A potential for the selective synovial sensitization with endogenous PpIX in comparison with cartilage tissue has been demonstrated in vitro after application of ALA or ALA-Me.
Collapse
Affiliation(s)
- Romualdas Rudys
- Biophotonics Group of Laser Research Center, Faculty of Physics, Vilnius University, Sauletekio 9, bldg. 3, Vilnius LT-10222, Lithuania; State Research Institute Centre for Innovative Medicine, Zygimantu 9, Vilnius LT-01102, Lithuania.
| | - Jaroslav Denkovskij
- State Research Institute Centre for Innovative Medicine, Zygimantu 9, Vilnius LT-01102, Lithuania.
| | - Gailutė Kirdaitė
- State Research Institute Centre for Innovative Medicine, Zygimantu 9, Vilnius LT-01102, Lithuania.
| | - Saulius Bagdonas
- Biophotonics Group of Laser Research Center, Faculty of Physics, Vilnius University, Sauletekio 9, bldg. 3, Vilnius LT-10222, Lithuania.
| |
Collapse
|
7
|
Collins J, Moots R, Winstanley R, Clegg P, Milner P. Oxygen and pH-sensitivity of human osteoarthritic chondrocytes in 3-D alginate bead culture system. Osteoarthritis Cartilage 2013; 21:1790-8. [PMID: 23850530 PMCID: PMC3807787 DOI: 10.1016/j.joca.2013.06.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/25/2013] [Accepted: 06/27/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To identify the effect of alterations in physical parameters such as oxygen and pH on processes associated with cellular redox balance in osteoarthritic chondrocytes. METHOD Human osteoarthritic chondrocytes (HOAC) were isolated from total knee arthroplasty samples and cultured in 3-D alginate beads in four different oxygen tensions (<1%, 2%, 5% and 21% O2), at pH 7.2 and 6.2 and in the presence or absence of 10 ng/ml, interleukin-1β (IL-1β). Cell viability, media glycosaminoglycan (GAG) levels, media nitrate/nitrate levels, active matrix metalloproteinase (MMP)-13 and intracellular adenosine triphosphate (ATPi) were measured over a 96-h time course. Intracellular reactive oxygen species (ROS), mitochondrial membrane potential, intracellular pH and reduced/oxidised glutathione (GSH/GSSG) were additionally measured after 48-h incubation under these experimental conditions. RESULTS Hypoxia (2% O2) and anoxia (<1% O2), acidosis (pH 6.2) and 10 ng/ml IL-1β reduced HOAC cell viability and increased GAG media levels. Acidosis and IL-1β increased nitrite/nitrate release, but increases were moderate at 2% O2 and significantly reduced at <1% O2. ATPi was significantly reduced following hypoxia and anoxia and acidosis. At 48 h cellular ROS levels were increased by acidosis and IL-1β but reduced in hypoxia and anoxia. Mitochondrial membrane potential was reduced in low oxygen, acidosis and IL-1β. Anoxia also resulted in intracellular acidosis. GSH/GSSG ratio was reduced in low oxygen conditions, acidosis and IL-1β. CONCLUSIONS This study shows that oxygen and pH affect elements of the redox system in HOAC including cellular anti-oxidants, mitochondrial membrane potential and ROS levels.
Collapse
Affiliation(s)
- J.A. Collins
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK
| | - R.J. Moots
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, University Hospital, Aintree, Liverpool L9 7AL, UK
| | - R. Winstanley
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK
| | - P.D. Clegg
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK
| | - P.I. Milner
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK,Address correspondence and reprint requests to: P.I. Milner, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst Campus, Neston, Cheshire CH64 7TE, UK. Tel: 44-151-7946041; Fax: 44-151-7946034.
| |
Collapse
|
8
|
Martin JA, Martini A, Molinari A, Morgan W, Ramalingam W, Buckwalter JA, McKinley TO. Mitochondrial electron transport and glycolysis are coupled in articular cartilage. Osteoarthritis Cartilage 2012; 20:323-9. [PMID: 22305999 PMCID: PMC3634328 DOI: 10.1016/j.joca.2012.01.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 12/06/2011] [Accepted: 01/10/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Although the majority of the adenosine triphosphate (ATP) in chondrocytes is made by glycolysis rather than by oxidative phosphorylation in mitochondria there is evidence to suggest that reactive oxygen species produced by mitochondrial electron transport (ET) help to maintain cellular redox balance in favor of glycolysis. The objective of this study was to test this hypothesis by determining if rotenone, which inhibits ET and blocks oxidant production inhibits glycolytic ATP synthesis. DESIGN Bovine osteochondral explants were treated with rotenone, an ET inhibitor; or oligomycin an ATP synthase inhibitor; or 2-fluoro-2-deoxy-D-glucose, a glycolysis inhibiter; or peroxide, an exogenous oxidant; or mitoquinone (MitoQ), a mitochondria-targeted anti-oxidant. Cartilage extracts were assayed for ATP, nicotine adenine dinucleotide (NAD+/H), and culture medium was assayed for pyruvate and lactate after 24 h of treatment. Imaging studies were used to measure superoxide production in cartilage. RESULTS Rotenone and 2-FG caused a significant decline in cartilage ATP (P < 0.001). In contrast, ATP levels were not affected by oligomycin. Peroxide treatment blocked rotenone effects on ATP, while treatment with MitoQ significantly suppressed ATP levels. Rotenone and 2-FG caused a significant decline in pyruvate, but not in lactate production. NADH:NAD+ ratios decreased significantly in both rotenone and 2-FG-treated explants (P < 0.05). Rotenone also significantly reduced superoxide production. CONCLUSIONS These findings showing a link between glycolysis and ET are consistent with previous reports on the critical need for oxidants to support normal chondrocyte metabolism. They suggest a novel role for mitochondria in cartilage homeostasis that is independent of oxidative phosphorylation.
Collapse
Affiliation(s)
- James A. Martin
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA,Corresponding author. 500 Newton Road, 1182 Medical Laboratories, Iowa City, Iowa 52242, USA
| | - Anne Martini
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Alexander Molinari
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Walter Morgan
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Wendy Ramalingam
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Joseph A. Buckwalter
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA,Veterans Affaires Medical Center, Iowa City, Iowa
| | - Todd O. McKinley
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| |
Collapse
|
9
|
Kuo J, Shi C, Cisewski S, Zhang L, Kern MJ, Yao H. Regional cell density distribution and oxygen consumption rates in porcine TMJ discs: an explant study. Osteoarthritis Cartilage 2011; 19:911-8. [PMID: 21397032 PMCID: PMC3132219 DOI: 10.1016/j.joca.2011.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 02/11/2011] [Accepted: 03/01/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the regional cell density distribution and basal oxygen consumption rates (based on tissue volume and cell number) of temporomandibular joint (TMJ) discs and further examine the impact of oxygen tension on these rates. DESIGN TMJ discs from pigs aged 6-8 months were divided into five regions: anterior, intermediate, posterior, lateral and medial. The cell density was determined using confocal laser scanning microscopy. The change in oxygen tension was recorded while TMJ disc explants were cultured in sealed metabolism chambers. The volume based oxygen consumption rate of explants was determined by theoretical curve-fitting of the recorded oxygen tension data with the Michaelis-Menten equation. The rate on a per-cell basis was calculated based on the cell density measurements and volume based rate measured in another group of discs. RESULTS The overall cell density [mean, 95% confidence interval (CI)] was 51.3 (21.3-81.3) × 10(6) cells/mL wet tissue. Along the anteroposterior axis, the anterior band had 25.5% higher cell density than the intermediate zone (P<0.02) and 29.1% higher than the posterior band (P<0.008). Along the mediolateral axes, the medial region had 26.2% higher cell density than the intermediate zone (P<0.04) and 25.4% higher than the lateral region (P<0.045). The overall volume and cell based maximum oxygen consumption rates were 1.44 (0.44-2.44) μmol/mL wet tissue/h and 28.7 (12.2-45.2)nmol/10(6)cells/h, respectively. The central regions (intermediate, lateral, and medial) had significantly higher volume based (P<0.02) and cell based (P<0.005) oxygen consumption rates than the anterior and posterior bands. At high oxygen tension, the oxygen consumption rate remained constant, but dropped as oxygen tension fell below 5%. CONCLUSIONS The TMJ disc had higher cell density and oxygen consumption rates than articular cartilage reported in the literature. These results suggest that a steeper oxygen gradient may exist in the TMJ disc and may be vulnerable to pathological events that impede nutrient supply.
Collapse
Affiliation(s)
- Jonathan Kuo
- Department of Bioengineering, Clemson University, Clemson, SC
| | - Changcheng Shi
- Department of Bioengineering, Clemson University, Clemson, SC
| | - Sarah Cisewski
- Department of Bioengineering, Clemson University, Clemson, SC
| | - Lixia Zhang
- Department of Craniofacial Biology, Medical University of South Carolina (MUSC), Charleston, SC
| | - Michael J. Kern
- Department of Craniofacial Biology, Medical University of South Carolina (MUSC), Charleston, SC
| | - Hai Yao
- Department of Bioengineering, Clemson University, Clemson, SC
- Department of Craniofacial Biology, Medical University of South Carolina (MUSC), Charleston, SC
| |
Collapse
|
10
|
White R, Gibson JS. The effect of oxygen tension on calcium homeostasis in bovine articular chondrocytes. J Orthop Surg Res 2010; 5:27. [PMID: 20420658 PMCID: PMC2873548 DOI: 10.1186/1749-799x-5-27] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 04/26/2010] [Indexed: 01/11/2023] Open
Abstract
Background Articular chondrocytes normally experience a lower O2 tension compared to that seen by many other tissues. This level may fall further in joint disease. Ionic homeostasis is essential for chondrocyte function but, at least in the case of H+ ions, it is sensitive to changes in O2 levels. Ca2+ homeostasis is also critical but the effect of changes in O2 tension has not been investigated on this parameter. Here we define the effect of hypoxia on Ca2+ homeostasis in bovine articular chondrocytes. Methods Chondrocytes from articular cartilage slices were isolated enzymatically using collagenase. Cytoplasmic Ca2+ levels ([Ca2+]i) were followed fluorimetrically using Fura-2 to determine the effect of changes in O2 tension. The effects of ion substitution (replacing extracellular Na+ with NMDG+ and chelating Ca2+ with EGTA) were tested. Levels of reactive oxygen species (ROS) and the mitochondrial membrane potential were measured and correlated with [Ca2+]i. Results A reduction in O2 tension from 20% to 1% for 16-18 h caused [Ca2+]i to approximately double, reaching 105 ± 23 nM (p < 0.001). Ion substitutions indicated that Na+/Ca2+ exchange activity was not inhibited at low O2 levels. At 1% O2, ROS levels fell and mitochondria depolarised. Restoring ROS levels (with an oxidant H2O2, a non-specific ROS generator Co2+ or the mitochondrial complex II inhibitor antimycin A) concomitantly reduced [Ca2+]i. Conclusions O2 tension exerts a significant effect on [Ca2+]i. The proposed mechanism involves ROS from mitochondria. Findings emphasise the importance of using realistic O2 tensions when studying the physiology and pathology of articular cartilage and the potential interactions between O2, ROS and Ca2+.
Collapse
Affiliation(s)
- Rachel White
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 OES, UK.
| | | |
Collapse
|
11
|
Heywood HK, Lee DA. Low oxygen reduces the modulation to an oxidative phenotype in monolayer-expanded chondrocytes. J Cell Physiol 2009; 222:248-53. [PMID: 19795395 DOI: 10.1002/jcp.21946] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Autologous chondrocyte implantation requires a phase of in vitro cell expansion, achieved by monolayer culture under atmospheric oxygen levels. Chondrocytes reside under low oxygen conditions in situ and exhibit a glycolytic metabolism. However, oxidative phosphorylation rises progressively during culture, with concomitant reactive oxygen species production. We determine if the high oxygen environment in vitro provides the transformation stimulus. Articular chondrocytes were cultured in monolayer for up to 14 days under 2%, 5%, or 20% oxygen. Expansion under 2% and 5% oxygen reduced the rate at which the cells developed an oxidative phenotype compared to 20% oxygen. However, at 40 +/- 4 fmol cell(-1) h(-1) the oxygen consumption by chondrocytes expanded under 2% oxygen for 14 days was still 14 times the value observed for freshly isolated cells. Seventy-five to 78% of the increased oxygen consumption was accounted for by oxidative phosphorylation (oligomycin sensitive). Expansion under low oxygen also reduced cellular proliferation and 8-hydroxyguanosine release, a marker of oxidative DNA damage. However, these parameters remained elevated compared to freshly isolated cells. Thus, expansion under physiological oxygen levels reduces, but does not abolish, the induction of an oxidative energy metabolism. We conclude that simply transferring chondrocytes to low oxygen is not sufficient to either maintain or re-establish a normal energy metabolism. Furthermore, a hydrophobic polystyrene culture surface which promotes rounded cell morphology had no effect on the development of an oxidative metabolism. Although the shift towards an oxidative energy metabolism is often accompanied by morphological changes, this study does not support the hypothesis that it is driven by them.
Collapse
Affiliation(s)
- Hannah K Heywood
- School of Engineering and Materials Science, Queen Mary University of London, London, UK.
| | | |
Collapse
|
12
|
Boubriak OA, Brooks JTS, Urban JPG. Cytochrome c oxidase levels in chondrocytes during monolayer expansion and after return to three dimensional culture. Osteoarthritis Cartilage 2009; 17:1084-92. [PMID: 19303470 DOI: 10.1016/j.joca.2009.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 02/12/2009] [Accepted: 03/04/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Here we investigate whether monolayer culture or culture at 21% oxygen influences activity of cytochrome c oxidase, the terminal enzyme in the respiratory chain whose activity is essential for oxidative metabolism and whether return to three dimensional (3-D) culture restores cytochrome c oxidase activity to original levels. METHODS Primary bovine articular chondrocytes were cultured in alginate beads (3-D) for 4 weeks or in monolayer under 1% and 21% oxygen for up to 9 days and then returned to 3-D culture for up to 4 weeks. Cells were stained to localise cytochrome c oxidase within the cells. Mitochondrial protein content and cytochrome c oxidase enzymatic activity were determined. Expression of cytochrome c oxidase subunits, COXI and COXIV, was assessed by qRT-PCR. RESULTS Cytochrome c oxidase staining remained minimal in chondrocytes cultured in alginate for 4 weeks under 21% oxygen. Mitochondrial protein content and cytochrome c oxidase activity increased significantly during 9 days of chondrocyte expansion in monolayer, accompanied by up-regulation of the COXI mitochondrial gene but not the COXIV nuclear-encoded gene. Cytochrome c oxidase staining increased from day 5 of monolayer culture and remained high even after the cells were returned to 3-D culture for 4 weeks. CONCLUSIONS Culture of chondrocytes in monolayer leads to a rapid increase in mitochondrial protein content and cytochrome c oxidase activity. The increase in cytochrome c oxidase activity is not reversed even after chondrocytes are returned to 3-D culture for 4 weeks; high oxygen tension alone does not appear to stimulate cytochrome c oxidase activity.
Collapse
Affiliation(s)
- O A Boubriak
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
| | | | | |
Collapse
|
13
|
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M. Differential response of porcine osteoblasts and chondrocytes in cell or tissue culture after 5-aminolevulinic acid-based photodynamic therapy. Osteoarthritis Cartilage 2009; 17:539-46. [PMID: 18838280 DOI: 10.1016/j.joca.2008.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Accepted: 08/26/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Outcome in osteochondral allografting is limited by the immunological incompatibility of the grafted tissue. Based on a resistance of chondrocytes to photodynamic therapy in cell culture it is proposed that 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) might be used to inactivate bone while maintaining viability of chondrocytes and thus immunomodulate bone selectively. METHODS Chondrocytes and osteoblasts from porcine humeral heads were either isolated (cell culture) or treated in situ (tissue culture). To quantify cytotoxic effects of 5-ALA-PDT (0-20 J/cm(2), 100 mW/cm(2)) an (3-(4,5-dimethylthiazol-2-yl)-2,5-di-phenyltetrazolium bromide) (MTT)-assay was used in cell culture and in situ hybridization in tissue culture to assess metabolic active cells (functional osteoblasts: col alpha(1)(I) mRNA, functional chondrocytes: col alpha(1)(II) mRNA). RESULTS In cell culture, survival after 5-ALA-PDT was significantly higher for chondrocytes (5 J/cm(2): 87+/-12% compared to untreated cells) than for osteoblasts (5J/cm(2): 12+/-11%). In tissue culture, the percentage of functional chondrocytes in cartilage showed a decrease after 5-ALA-PDT (direct fixation: 92+/-2%, 20 J/cm(2): 35+/-15%; P<0.0001). A significant decrease in the percentage of bone surfaces covered by functional osteoblasts was observed in freshly harvested (31+/-3%) compared to untreated tissues maintained in culture (11+/-4%, P<0.0001), with no further decrease after 5-ALA-PDT. CONCLUSION Chondrocytes were more resistant to 5-ALA-PDT than osteoblasts in cell culture, while in tissue culture a loss of functional chondrocytes was observed after 5-ALA-PDT. Since osteoblasts - but not chondrocytes - were sensitive to the tissue culture conditions, devitalized bone with functional cartilage might already be achieved by applying specific tissue culture conditions even without 5-ALA-PDT.
Collapse
Affiliation(s)
- J D Bastian
- Department of Clinical Research, Group for Bone Biology and Orthopaedic Research, University of Bern, Switzerland.
| | | | | | | | | |
Collapse
|
14
|
Kandel R, Roberts S, Urban JPG. Tissue engineering and the intervertebral disc: the challenges. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2008; 17 Suppl 4:480-91. [PMID: 19005701 DOI: 10.1007/s00586-008-0746-2] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 07/13/2008] [Accepted: 07/13/2008] [Indexed: 12/25/2022]
Abstract
Disc degeneration is a common disorder. Although the back pain that can develop in association with this is rarely life-threatening, the annual cost in terms of morbidity, lost productivity, medical expenses and workers' compensation benefits is significant. Surgical intervention as practised currently is directed towards removing the damaged or altered tissue. Development of new treatment modalities is critical as there is a growing consensus that the strategies used currently for symptomatic degenerative disc disease may not be effective. Accordingly, there is a need to develop an entirely new way to treat this disorder; regenerative medicine and tissue engineering approaches appear particularly promising in this regard. This paper reviews some of the challenges that currently are limiting the clinical application of this approach to the treatment of disc degeneration.
Collapse
Affiliation(s)
- Rita Kandel
- CIHR-Bioengineering of Skeletal Tissues Team, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.
| | | | | |
Collapse
|
15
|
Heywood H, Lee D. Monolayer expansion induces an oxidative metabolism and ROS in chondrocytes. Biochem Biophys Res Commun 2008; 373:224-9. [DOI: 10.1016/j.bbrc.2008.06.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 06/03/2008] [Indexed: 01/24/2023]
|
16
|
Egli RJ, Di Criscio A, Hempfing A, Schoeniger R, Ganz R, Hofstetter W, Leunig M. In vitro resistance of articular chondrocytes to 5-Aminolevulinic acid based photodynamic therapy. Lasers Surg Med 2008; 40:282-90. [DOI: 10.1002/lsm.20625] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Egli RJ, Schober M, Hempfing A, Ganz R, Hofstetter W, Leunig M. Sensitivity of osteoblasts, fibroblasts, bone marrow cells, and dendritic cells to 5-aminolevulinic acid based photodynamic therapy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 89:70-7. [DOI: 10.1016/j.jphotobiol.2007.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 09/03/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
|
18
|
Gibson JS, Milner PI, White R, Fairfax TPA, Wilkins RJ. Oxygen and reactive oxygen species in articular cartilage: modulators of ionic homeostasis. Pflugers Arch 2007; 455:563-73. [PMID: 17849146 DOI: 10.1007/s00424-007-0310-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 06/20/2007] [Indexed: 11/26/2022]
Abstract
Articular cartilage is an avascular tissue dependent on diffusion mainly from synovial fluid to service its metabolic requirements. Levels of oxygen (O(2)) in the tissue are low, with estimates of between 1 and 6%. Metabolism is largely, if not entirely, glycolytic, with little capacity for oxidative phosphorylation. Notwithstanding, the tissue requires O(2) and consumes it, albeit at low rates. Changes in O(2) tension also have profound effects on chondrocytes affecting phenotype, gene expression, and morphology, as well as response to, and production of, cytokines. Although chondrocytes can survive prolonged anoxia, low O(2) levels have significant metabolic effects, inhibiting glycolysis (the negative Pasteur effect), and also notably matrix production. Why this tissue should respond so markedly to reduction in O(2) tension remains a paradox. Ion homeostasis in articular chondrocytes is also markedly affected by the extracellular matrix in which the cells reside. Recent work has shown that ion homeostasis also responds to changes in O(2) tension, in such a way as to produce significant effects on cell function. For this purpose, O(2) probably acts via alteration in levels of reactive oxygen species. We discuss the possibility that O(2) consumption by this tissue is required to maintain levels of ROS, which are then used physiologically as an intracellular signalling device. This postulate may go some way towards explaining why the tissue is dependent on O(2) and why its removal has such marked effects. Understanding the role of oxygen has implications for disease states in which O(2) or ROS levels may be perturbed.
Collapse
Affiliation(s)
- J S Gibson
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, England
| | | | | | | | | |
Collapse
|
19
|
Milner PI, Fairfax TPA, Browning JA, Wilkins RJ, Gibson JS. The effect of O2 tension on pH homeostasis in equine articular chondrocytes. ACTA ACUST UNITED AC 2006; 54:3523-32. [PMID: 17075856 DOI: 10.1002/art.22209] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To determine the effects of varying O(2) on pH homeostasis, based on the hypothesis that the function of articular chondrocytes is best understood at realistic O(2) tensions. METHODS Cartilage from equine metacarpophalangeal/tarsophalangeal joints was digested with collagenase to isolate chondrocytes, and then loaded with the pH-sensitive fluorophore 2',7'-bis-2-(carboxyethyl)-5(6)-carboxylfluorescein. The radioisotope(22)Na(+) was used to determine the kinetics of Na(+)/H(+) exchange (NHE) and the activity of the Na(+)/K(+) pump, and ATP levels were assessed with luciferin assays. Levels of reactive oxygen species (ROS) were determined using 2',7'-dichlorofluorescein diacetate. RESULTS The pH homeostasis was unaffected when comparing tissue maintained at 20% O(2) (the level in water-saturated air at 37 degrees C) with that at 5% O(2) (which approximates the normal level in healthy cartilage); however, an O(2) tension of <5% caused a fall in intracellular pH (pH(i)) and slowed pH(i) recovery following acidification, an effect mediated via inhibition of NHE activity (likely through acid extrusion by NHE isoform 1). The Na(+)/K(+) pump activity and intracellular ATP concentration were unaffected by hypoxia, but the levels of ROS were reduced. Hypoxic inhibition of NHE activity and the reduction in ROS levels were reversed by treatment with H(2)O(2), Co(2+), or antimycin A. Treatment with calyculin A also prevented hypoxic inhibition of NHE activity. CONCLUSION The ability of articular chondrocytes to carry out pH homeostasis is compromised when O(2) tensions fall below those normally experienced, via inhibition of NHE. The putative signal is a reduction in levels of ROS derived from mitochondria, acting via altered protein phosphorylation. This effect is relevant to both physiologic and pathologic states of lowered O(2), such as in chronic inflammation.
Collapse
|
20
|
Heywood HK, Bader DL, Lee DA. Rate of oxygen consumption by isolated articular chondrocytes is sensitive to medium glucose concentration. J Cell Physiol 2005; 206:402-10. [DOI: 10.1002/jcp.20491] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
21
|
Lee RB, Urban JPG. Functional replacement of oxygen by other oxidants in articular cartilage. ARTHRITIS AND RHEUMATISM 2002; 46:3190-200. [PMID: 12483723 DOI: 10.1002/art.10686] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Articular cartilage chondrocytes consume remarkably little O(2) in comparison with most other animal cells; glycolysis forms the principal source of ATP in this cartilage. Although not lethal for many days, imposition of anoxia immediately lowers intracellular ATP, inhibits rates of glycolysis, and prevents articular chondrocytes from producing extracellular matrix macromolecules. This study was undertaken to investigate the role of O(2) in articular chondrocyte metabolism. METHODS We examined the effects of oxygen and of several other classes of exogenous oxidants, i.e., 1) the dyes methylene blue and 2,6-dichlorophenol-indophenol, 2) the iron (III) complex ferricyanide, and 3) the keto-acids oxaloacetate and pyruvate (and phosphoenolpyruvate, a metabolic precursor of pyruvate), on rates of glycolysis and of sulfate incorporation by bovine articular cartilage in vitro. RESULTS Lactate production was lowest under conditions of anoxia and was stimulated severalfold by addition of O(2) (air-saturated medium). Under strict anoxia, other oxidants restored lactate production to rates at least comparable with those seen in aerobic controls; under aerobic conditions, they had little effect. Oxygen and all of the other oxidants examined stimulated sulfate incorporation more strongly than lactate production. The compounds that promoted glycolysis and hence sulfate incorporation in cartilage under anoxia were themselves reduced; that is, they functioned as oxidants in lieu of O(2). CONCLUSION For normal function, articular cartilage appears to require exogenous oxidants to stimulate glycolysis and produce ATP and extracellular matrix. Under physiologic conditions, oxygen acts as this oxidant, but its role can be adequately assumed by other agents.
Collapse
|
22
|
Abstract
Uptake of external glucose and production of lactate were measured in freshly-excised bovine articular cartilage under O2 concentrations ranging from 21% (air) to zero (N2-bubbled). Anoxia (O2 concentration < 1% in the gas phase) severely inhibited both glucose uptake and lactate production. The decrease in lactate formation correlated closely with the decrease in glucose uptake, in a mole ratio of 2:1. This reduction in the rate of glycolysis in anoxic conditions is seen as evidence of a negative Pasteur effect in bovine articular cartilage. Anoxia also suppressed glycolysis in articular cartilage from horse, pig and sheep. Inhibitors acting on the glycolytic pathway (2-deoxy-D-glucose, iodoacetamide or fluoride) strongly decreased aerobic lactate production and ATP concentration, consistent with the belief that articular cartilage obtains its principal supply of ATP from substrate-level phosphorylation in glycolysis. Azide or cyanide lowered the ATP concentration in aerobic cartilage to approximately the same extent as did anoxia but, because glycolysis (lactate production) was also inhibited by these treatments, the importance of any mitochondrial ATP production could not be assessed. A negative Pasteur effect would make chondrocytes particularly liable to suffer a shortage of energy under anoxic conditions. Incorporation of [35S]sulphate into proteoglycan was severely curtailed by treatments, such as anoxia, which decreased the intracellular concentration of ATP.
Collapse
Affiliation(s)
- R B Lee
- University Laboratory of Physiology, University of Oxford, U.K
| | | |
Collapse
|
23
|
Haraguchi Y, Chung A, Neill S, Wallace D. OXBOX and REBOX, overlapping promoter elements of the mitochondrial F0F1-ATP synthase beta subunit gene. OXBOX/REBOX in the ATPsyn beta promoter. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37112-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|