Ameliorating Glycosaminoglycan (GAG) Loss and Cell Death in Articular Cartilage Following Single-Impact Loading

Author(s):  
Roman M. Natoli ◽  
Kyriacos A. Athanasiou

Impact loading of articular cartilage leads to post-traumatic osteoarthritis (OA) through its effects on the cells and extracellular matrix (ECM) of the tissue. Studies have shown the level of impact or injurious compression correlates with increased cell death, degradation of the ECM, and detrimental changes in biomechanical properties [1]. Recently, several bioactive agents, such as P188 and IGF-I, have shown promising results by reducing cell death following injurious compression of cartilage explants [2, 3].

1992 ◽  
Vol 288 (3) ◽  
pp. 721-726 ◽  
Author(s):  
A J Curtis ◽  
R J Devenish ◽  
C J Handley

The addition of serum or insulin-like growth factor-I (IGF-I) to the medium of explant cultures of bovine articular cartilage is known to stimulate the synthesis of aggrecan in a dose-dependent manner. The half-life of the pool of proteoglycan core protein was measured in adult articular cartilage cultured for 6 days in the presence and absence of 20 ng of IGF-I/ml and shown to be 24 min under both sets of conditions. The half-life of the mRNA pool coding for aggrecan was also determined and shown to be approx. 4 h in cartilage maintained in culture with or without IGF-I. The pool size of mRNA coding for aggrecan core protein increased 5-6-fold in cartilage explants maintained in culture in medium containing 20% (v/v) fetal-calf serum; however, in tissue maintained with medium containing IGF-I there was no increase in the cellular levels of this mRNA. This suggests that aggrecan synthesis is stimulated by IGF-I at the level of translation of mRNA coding for the core protein of this proteoglycan and that other growth factors are present in serum that stimulate aggrecan synthesis at the level of transcription of the core-protein gene. Inclusion of serum or IGF-I in the medium of cartilage explant cultures induced increases in the amounts of mRNA coding for type II collagen and link protein, whereas only serum enhanced the amount of mRNA for the core protein of decorin.


2020 ◽  
Vol 21 (2) ◽  
pp. 666 ◽  
Author(s):  
Ping Li ◽  
Lutz Fleischhauer ◽  
Claudia Nicolae ◽  
Carina Prein ◽  
Zsuzsanna Farkas ◽  
...  

Matrilins (MATN1, MATN2, MATN3 and MATN4) are adaptor proteins of the cartilage extracellular matrix (ECM), which bridge the collagen II and proteoglycan networks. In humans, dominant-negative mutations in MATN3 lead to various forms of mild chondrodysplasias. However, single or double matrilin knockout mice generated previously in our laboratory do not show an overt skeletal phenotype, suggesting compensation among the matrilin family members. The aim of our study was to establish a mouse line, which lacks all four matrilins and analyze the consequence of matrilin deficiency on endochondral bone formation and cartilage function. Matn1-4−/− mice were viable and fertile, and showed a lumbosacral transition phenotype characterized by the sacralization of the sixth lumbar vertebra. The development of the appendicular skeleton, the structure of the growth plate, chondrocyte differentiation, proliferation, and survival were normal in mutant mice. Biochemical analysis of knee cartilage demonstrated moderate alterations in the extractability of the binding partners of matrilins in Matn1-4−/− mice. Atomic force microscopy (AFM) revealed comparable compressive stiffness but higher collagen fiber diameters in the growth plate cartilage of quadruple mutant compared to wild-type mice. Importantly, Matn1-4−/− mice developed more severe spontaneous osteoarthritis at the age of 18 months, which was accompanied by changes in the biomechanical properties of the articular cartilage. Interestingly, Matn4−/− mice also developed age-associated osteoarthritis suggesting a crucial role of MATN4 in maintaining the stability of the articular cartilage. Collectively, our data provide evidence that matrilins are important to protect articular cartilage from deterioration and are involved in the specification of the vertebral column.


Author(s):  
Adam Levin ◽  
Peter A. Torzilli ◽  
C. T. Christopher Chen

A recent study showed that exposure to hypotonic conditions increased chondrocyte surface area up to 234% by stretching the folded membrane, which may reduce the chondrocyte’s ability to deform under load. The goal of this study was to determine the effect of hypo-osmolarity on chondrocyte survival from load-induced injury. Bovine cartilage explants were incubated in either isotonic or hypotonic pH-buffered solution for 20 minutes, loaded with cyclic confined compression at 5MPa for 1 hour, and then assessed for cell viability using cell vital dyes and for pericellular matrix (PCM) using an type VI collagen antibody. Cell death in loaded explants was significantly greater than that of non-loaded controls (p<0.001). However, explants loaded in the hypotonic solution showed significantly greater cell death than those loaded in the isotonic solution. An increase of dead cells with flatten PCM were located in the superficial zone. Our findings suggest that hypo-osmolarity decreases the ability of chondrocytes in articular cartilage to survive from load-induced injury.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Motoo Saito ◽  
Kohei Nishitani ◽  
Hanako O. Ikeda ◽  
Shigeo Yoshida ◽  
Sachiko Iwai ◽  
...  

AbstractPost-traumatic osteoarthritis (PTOA) is a major cause which hinders patients from the recovery after intra-articular injuries or surgeries. Currently, no effective treatment is available. In this study, we showed that inhibition of the acute stage chondrocyte death is a promising strategy to mitigate the development of PTOA. Namely, we examined efficacies of Kyoto University Substance (KUS) 121, a valosin-containing protein modulator, for PTOA as well as its therapeutic mechanisms. In vivo, in a rat PTOA model by cyclic compressive loading, intra-articular treatments of KUS121 significantly improved the modified Mankin scores and reduced damaged-cartilage volumes, as compared to vehicle treatment. Moreover, KUS121 markedly reduced the numbers of TUNEL-, CHOP-, MMP-13-, and ADAMTS-5-positive chondrocytes in the damaged knees. In vitro, KUS121 rescued human articular chondrocytes from tunicamycin-induced cell death, in both monolayer culture and cartilage explants. It also significantly downregulated the protein or gene expression of ER stress markers, proinflammatory cytokines, and extracellular-matrix-degrading enzymes induced by tunicamycin or IL-1β. Collectively, these results demonstrated that KUS121 protected chondrocytes from cell death through the inhibition of excessive ER stress. Therefore, KUS121 would be a new, promising therapeutic agent with a protective effect on the progression of PTOA.


2003 ◽  
Vol 57 (7) ◽  
pp. 314-319 ◽  
Author(s):  
Giordano Stabellini ◽  
Monica De Mattei ◽  
Carla Calastrini ◽  
Nicoletta Gagliano ◽  
Claudia Moscheni ◽  
...  

2011 ◽  
Vol 70 (4) ◽  
pp. 683-689 ◽  
Author(s):  
Kristen M Clements ◽  
Jo K Flannelly ◽  
Jonathan Tart ◽  
Sarah M V Brockbank ◽  
John Wardale ◽  
...  

ObjectiveAggrecan is a critical component of cartilage extracellular matrix. Several members of the ‘a disintegrin and metalloproteinase with thrombospondin motifs’ (ADAMTS) family have been characterised as aggrecanases by their ability to generate fragments containing the NITEGE neoepitope from aggrecan. Increased NITEGE fragments in synovial fluid and articular cartilage are a hallmark of osteoarthritis (OA) and it is hypothesised that the enhanced rate of aggrecan degradation is critical for cartilage destruction in OA. Recently, matrix metalloproteinase 17 (MMP17, also known as MT4-MMP) has been implicated in the activation of one of the key aggrecanases: ADAMTS4. In the present work, the hypothesis that MMP17 mediates the interleukin 1β (IL-1β) induced release of NITEGE neoepitope from human and murine articular cartilage is investigated.MethodsMMP17 was quantified at the protein and RNA level and NITEGE neoepitope generation by immunohistochemistry. Human postmortem articular cartilage explants were treated with recombinant MMP17, or IL-1β in the presence or absence of an MMP17 inhibitor. Glycosaminoglycan (GAG) loss into the media was quantified using the 1,9-dimethylmethylene blue (DMMB) assay. Intra-articular injection (IAI) of IL-1β or meniscotibial ligament transaction was carried out in MMP17 null mice.ResultsThe data reveal an association between increased MMP17 protein and NITEGE staining in areas of OA cartilage damage. Ex vivo treatment of normal human cartilage with recombinant MMP17 protein increased NITEGE generation in the cartilage and GAG loss into the media. In addition, IL-1β mediated cartilage GAG loss, and increased NITEGE neoepitope expression, were attenuated with an MMP17 inhibitor.IAI of IL-1β into C57BL6/Jax mice resulted in increased MMP17 expression in articular cartilage and increased GAG content in the synovial fluid. MMP17 null mice were protected against this increase. However, aggrecan loss driven by mechanical stress following medial meniscotibial ligament transection was not dependent on MMP17.ConclusionThese data further implicate MMP17 in the control of articular cartilage extracellular matrix aggrecan integrity in an inflammatory environment.


1999 ◽  
Vol 194 (3) ◽  
pp. 343-353
Author(s):  
L. A. DURRANT ◽  
C. W. ARCHER ◽  
M. BENJAMIN ◽  
J. R. RALPHS

Articular cartilage undergoes cycles of compressive loading during joint movement, leading to its cyclical deformation and recovery. This loading is essential for chondrocytes to perform their normal function of maintenance of the extracellular matrix. Various lines of evidence suggest the involvement of the cytoskeleton in load sensing and response. The purpose of the present study is to describe the 3-dimensional (3D) architecture of the cytoskeleton of chondrocytes within their extracellular matrix, and to examine cytoskeletal responses to experimentally varied mechanical conditions. Uniformly sized explants of articular cartilage were dissected from adult rat femoral heads. Some were immediately frozen, cryosectioned and labelled for filamentous actin using phalloidin, and for the focal contact component vinculin or for vimentin by indirect immunofluorescence. Sections were examined by confocal microscopy and 3D modelling. Actin occurred in all chondrocytes, appearing as bright foci at the cell surface linked to an irregular network beneath the surface. Cell surface foci colocalised with vinculin, suggesting the presence of focal contacts between the chondrocyte and its pericellular matrix. Vimentin label occurred mainly in cells of the deep zone. It had a complex intracellular distribution, with linked networks of fibres surrounding the nucleus and beneath the plasma membrane. When cartilage explants were placed into organ culture, where in the absence of further treatments cartilage imbibes fluid from the culture medium and swells, cytoskeletal changes were observed. After 1 h in culture the vimentin cytoskeleton was disassembled, leading to diffuse labelling of cells. After a further hour in culture filamentous vimentin label reappeared in deep zone chondrocytes, and then over the next 48 h became more widespread in cells of the explants. Actin distribution was unaffected by culture. Further experiments were performed to test the effects of load on the cytoskeleton. Explants were placed in culture and immediately subjected to static uniaxial radially unconfined compressive loads of 0.5, 1, 2 or 4 MPa for 1 h using a pneumatic loading device. Loads greater than 0.5 MPa maintained the vimentin organisation over the culture period. At 0.5 MPa, the chondrocytes within the explant behaved as in free-swelling culture. The rapid change in vimentin organisation probably relates to rapid swelling of the explants—under free-swelling conditions, these reached their maximum swollen size in just 15 min of culture. The chondrocytes' response to change in tissue dimensions, and thus to their relationship to their immediate environment, was to disassemble their vimentin networks. Loading probably counteracts the swelling pressure of the tissue. Overall, this work suggests that chondrocytes maintain their actin cytoskeleton and modify their vimentin cytoskeleton in response to changing mechanical conditions.


Author(s):  
Chen-Yuan Chung ◽  
Mostafa Motavalli ◽  
Joseph M. Mansour

Articular cartilage is a hydrated connective tissue consisting of a relatively small number of chondrocytes surrounded by a saturated extracellular matrix comprised mainly of type-II collagen fibrils and proteoglycans. As a deformable fluid saturated material, cartilage is most often modeled using biphasic or poroelastic theories [1,2]. The ultimate goal of this work is to evaluate biomechanical properties of native and tissue engineered cartilage under combined compression and shear. The purpose of this investigation was to determine stress and deformation fields in cartilage under compression and simple shear and relate these to measured results.


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