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  1. Article ; Online: The effects of cyclic tensile strain on the organisation and expression of cytoskeletal elements in bovine intervertebral disc cells

    S Li / X Jia / VC Duance / EJ Blain

    European Cells and Materials (ECM), Vol 21, Pp 508-

    an in vitro study

    2011  Volume 522

    Abstract: It is still relatively unclear how intervertebral disc (IVD) cells sense a mechanical stimulus and convert this signal into a biochemical response. Previous studies demonstrated that the cytoskeletal elements are mechano-responsive in many cell types and ...

    Abstract It is still relatively unclear how intervertebral disc (IVD) cells sense a mechanical stimulus and convert this signal into a biochemical response. Previous studies demonstrated that the cytoskeletal elements are mechano-responsive in many cell types and may contribute to mechano-signalling pathways. The objective of this study was to determine the response of cells from the outer annulus fibrosus (OAF) to physiological levels of cyclic tensile strain; further, cells from the nucleus pulposus (NP) were also subjected to an identical loading regime to compare biological responses across the IVD populations. We determined whether the organisation and expression of the major cytoskeletal elements and their associated accessory proteins are responsive to mechanical stimulation in these cells, and whether these changes correlated with either a catabolic or anabolic phenotype. OAF and NP cells from immature bovine IVD were seeded onto Flexcell® type I collagen coated plates. Cells were subjected to cyclic tensile strain (10 %, 1 Hz) for 60 minutes. Post-loading, cells were processed for immunofluorescence microscopy, RNA extracted for quantitative PCR and protein extracted for Western blotting analysis. F-actin reorganisation was evident in OAF and NP cells subjected to tensile strain; strain induced β-actin at the transcriptional and translational level in OAF cells. β-tubulin mRNA and protein synthesis increased in strained OAF cells, but vimentin expression was significantly inhibited. Cytoskeletal element organisation and expression were less responsive to strain in NP cells. Tensile strain increased type I collagen and differentially regulated extracellular matrix (ECM)-degrading enzymes’ mRNA levels in OAF cells. Strain induced type II collagen transcription in NP cells, but had no effect on the transcription of any other genes analysed. Tensile strain induces different mechano-responses in the organisation and/or expression of cytoskeletal elements and on markers of IVD metabolism. Differential mechano-regulation of anabolic and catabolic ECM components in the OAF and NP populations reflects their respective mechanical environments in situ.
    Keywords Intervertebral disc ; mechanotransduction ; cytoskeleton ; actin filaments ; microtubules ; intermediate filaments ; cyclic tensile strain ; nucleus pulposus ; outer annulus fibrosus ; extracellular matrix ; Biology (General) ; QH301-705.5 ; Science ; Q ; DOAJ:Biology ; DOAJ:Biology and Life Sciences ; Biochemistry ; QD415-436 ; Organic chemistry ; QD241-441 ; Chemistry ; QD1-999 ; DOAJ:Biochemistry ; DOAJ:Life Sciences
    Subject code 570
    Language English
    Publishing date 2011-06-01T00:00:00Z
    Publisher European Cells & Materials Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Protein kinase R plays a pivotal role in oncostatin M and interleukin-1 signalling in bovine articular cartilage chondrocytes

    SJ Gilbert / EJ Blain / A Al-Sabah / Y Zhang / VC Duance / DJ Mason

    European Cells and Materials (ECM), Vol 23, Pp 41-

    2012  Volume 57

    Abstract: This study investigated whether treatment of articular cartilage chondrocytes with a combination of oncostatin M (OSM) and interleukin-1 (IL-1) could induce a degradative phenotype that was mediated through the protein kinase R (PKR) signalling pathway. ... ...

    Abstract This study investigated whether treatment of articular cartilage chondrocytes with a combination of oncostatin M (OSM) and interleukin-1 (IL-1) could induce a degradative phenotype that was mediated through the protein kinase R (PKR) signalling pathway. High-density monolayer cultures of full depth, bovine chondrocytes were treated with a combination of OSM and IL-1 (OSM+IL-1) for 7 days. To inhibit the activation of PKR, a pharmacological inhibitor of PKR was added to duplicate cultures. Pro- and active matrix metalloproteinase-9 (MMP9) and MMP9 mRNA were significantly upregulated by OSM+IL-1 through a PKR dependent mechanism. ADAMTS4 and ADAMTS5 mRNA were also upregulated by OSM+IL-1. The upregulation of ADAMTS4 and ADAMTS5 were, in part, mediated through PKR. OSM+IL-1 resulted in a loss of type II collagen, which could not be rescued by PKR inhibition. OSM+IL-1 reduced the expression of COL2A1 (type II collagen), COL9A1 (type IX collagen), COL11A1 (type XI collagen), and ACAN (aggrecan) mRNAs. Expression of type II and XI collagen and aggrecan was reduced further when PKR was inhibited. OSM+IL-1 resulted in an 11-fold increase in TNFa mRNA which was, in part, mediated through the PKR pathway. This study demonstrates, for the first time, that a number of catabolic and pro-inflammatory effects known to be important in human arthritis and induced by OSM and IL-1, are mediated by the PKR signalling pathway.
    Keywords Articular cartilage ; chondrocytes ; protein kinase R ; oncostatin M ; interleukin-1 ; matrix metalloproteinase ; aggrecanase ; tumour necrosis factor alpha ; type II collagen ; Biology (General) ; QH301-705.5 ; Science ; Q ; DOAJ:Biology ; DOAJ:Biology and Life Sciences ; Biochemistry ; QD415-436 ; Organic chemistry ; QD241-441 ; Chemistry ; QD1-999 ; DOAJ:Biochemistry ; DOAJ:Life Sciences
    Subject code 610
    Language English
    Publishing date 2012-01-01T00:00:00Z
    Publisher European Cells & Materials Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Cartilage Integration

    IM Khan / SJ Gilbert / SK Singhrao / VC Duance / CW Archer

    European Cells and Materials (ECM), Vol 16, Pp 26-

    Evaluation of the reasons for failure of integration during cartilage repair. A review

    2008  Volume 39

    Abstract: Articular cartilage is a challenging tissue to reconstruct or replace principally because of its avascular nature; large chondral lesions in the tissue do not spontaneously heal. Where lesions do penetrate the bony subchondral plate, formation of ... ...

    Abstract Articular cartilage is a challenging tissue to reconstruct or replace principally because of its avascular nature; large chondral lesions in the tissue do not spontaneously heal. Where lesions do penetrate the bony subchondral plate, formation of hematomas and the migration of mesenchymal stem cells provide an inferior and transient fibrocartilagenous replacement for hyaline cartilage. To circumvent the poor intrinsic reparative response of articular cartilage several surgical techniques based on tissue transplantation have emerged. One characteristic shared by intrinsic reparative processes and the new surgical therapies is an apparent lack of lateral integration of repair or graft tissue with the host cartilage that can lead to poor prognosis. Many factors have been cited as impeding cartilage:cartilage integration including; chondrocyte cell death, chondrocyte dedifferentiation, the nature of the collagenous and proteoglycan networks that constitute the extracellular matrix, the type of biomaterial scaffold employed in repair and the origin of the cells used to repopulate the defect or lesion. This review addresses the principal intrinsic and extrinsic factors that impede integration and describe how manipulation of these factors using a host of strategies can positively influence cartilage integration.
    Keywords cartilage ; integration ; repair ; autologous chondrocyte implantation ; Biology (General) ; QH301-705.5 ; Science ; Q ; DOAJ:Biology ; DOAJ:Biology and Life Sciences ; Biochemistry ; QD415-436 ; Organic chemistry ; QD241-441 ; Chemistry ; QD1-999 ; DOAJ:Biochemistry ; DOAJ:Life Sciences
    Subject code 616 ; 337
    Language English
    Publishing date 2008-09-01T00:00:00Z
    Publisher European Cells & Materials Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Interleukin-1β enhances cartilage-to-cartilage integration

    IM Khan / LG Gonzalez / L Francis / RS Conlan / SJ Gilbert / SK Singhrao / D Burdon / P Hollander / VC Duance / CW Archer

    European Cells and Materials (ECM), Vol 22, Pp 190-

    2011  Volume 201

    Abstract: The failure of cartilages to fuse, particularly in the case of articular cartilage under conditions of repair is due to morphological and structural constraints of the tissue. Factors that impede integration include, non-vascularisation, low cellularity, ...

    Abstract The failure of cartilages to fuse, particularly in the case of articular cartilage under conditions of repair is due to morphological and structural constraints of the tissue. Factors that impede integration include, non-vascularisation, low cellularity, and proteoglycan in the surrounding extracellular matrix acting as a natural barrier to cellular migration. We hypothesised that brief activation of a catabolic cascade by cytokines followed by culture under anabolic conditions would promote tissue fusion in a ring-disk model of cartilage integration. Our results show that transient exposure to 10 ng mL-1 interleukin-1β, followed by two weeks post-culture under anabolic conditions, enhanced cartilage-cartilage integration compared to untreated explants. Quantitative PCR analysis of catabolism-related genes ADAMTS4 and MMP13 showed both were transiently upregulated and these findings correlated with evidence of extracellular matrix remodelling. At the level of histology, we observed chondrocytes readily populated the interfacial matrix between fused explants in interleukin-1β treated explants, whereas in control explants this region was relatively acellular in comparison. Catabolic cytokine treated explants exhibited 29-fold greater adhesive strength (0.859 MPa versus 0.028 MPa, P <0.05) than untreated counterparts. Collectively, our results demonstrate that a single short catabolic pulse followed by an anabolic response is sufficient to generate mechanically robust, integrative cartilage repair.
    Keywords Cartilage ; integration ; repair ; interleukin-1β ; Biology (General) ; QH301-705.5 ; Science ; Q ; DOAJ:Biology ; DOAJ:Biology and Life Sciences ; Biochemistry ; QD415-436 ; Organic chemistry ; QD241-441 ; Chemistry ; QD1-999 ; DOAJ:Biochemistry ; DOAJ:Life Sciences
    Subject code 616
    Language English
    Publishing date 2011-11-01T00:00:00Z
    Publisher European Cells & Materials Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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