Effect of Impact Load on Articular Cartilage: Cell Metabolism and Viability, and Matrix Water Content

1999 ◽  
Vol 121 (5) ◽  
pp. 433-441 ◽  
Author(s):  
P. A. Torzilli ◽  
R. Grigiene ◽  
J. Borrelli ◽  
D. L. Helfet
Keyword(s):  
Cell Death ◽  
Water Content ◽  
Impact Load ◽  
Cell Metabolism ◽  
Cartilage Explants ◽  
Critical Threshold ◽  
Limited Information ◽  
Impact Stress ◽  
Stress Dependent ◽  
Bovine Cartilage

Significant evidence exists that trauma to a joint produced by a single impact load below that which causes subchondral bone fracture can result in permanent damage to the cartilage matrix, including surface fissures, loss of proteoglycan, and cell death. Limited information exists, however, on the effect of a varying impact stress on chondrocyte biophysiology and matrix integrity. Based on our previous work, we hypothesized that a stress-dependent response exists for both the chondrocyte’s metabolic activity and viability and the matrix’s hydration. This hypothesis was tested by impacting bovine cartilage explants with nominal stresses ranging from 0.5 to 65 MPa and measuring proteoglycan biosynthesis, cell viability, and water content immediately after impaction and 24 hours later. We found that proteoglycan biosynthesis decreased and water content increased with increasing impact stress. However, there appeared to be a critical threshold stress (15–20 MPa) that caused cell death and apparent rupture of the collagen fiber matrix at the time of impaction. We concluded that the cell death and collagen rupture are responsible for the observed alterations in the tissue’s metabolism and water content, respectively, although the exact mechanism causing this damage could not be determined.

Hypo-Osmolarity Decreases the Ability of Cells in Articular Cartilage to Survive a Load-Induced Injury

2003 ◽  
Author(s):  
Adam Levin ◽  
Peter A. Torzilli ◽  
C. T. Christopher Chen
Keyword(s):  
Cell Death ◽  
Articular Cartilage ◽  
Cell Viability ◽  
Cartilage Explants ◽  
Hypotonic Solution ◽  
Pericellular Matrix ◽  
Isotonic Solution ◽  
Confined Compression ◽  
Superficial Zone ◽  
Bovine Cartilage

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.

scholarly journals p32 protein levels are integral to mitochondrial and endoplasmic reticulum morphology, cell metabolism and survival

2013 ◽  
Vol 453 (3) ◽  
pp. 381-391 ◽  
Author(s):  
MengJie Hu ◽  
Simon A. Crawford ◽  
Darren C. Henstridge ◽  
Ivan H. W. Ng ◽  
Esther J. H. Boey ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Stress Responses ◽  
Binding Protein ◽  
Cell Metabolism ◽  
Mitochondrial Protein ◽  
Basal Respiration ◽  
Protein Levels ◽  
Stress Dependent ◽  
The Impact

p32 [also known as HABP1 (hyaluronan-binding protein 1), gC1qR (receptor for globular head domains complement 1q) or C1qbp (complement 1q-binding protein)] has been shown previously to have both mitochondrial and non-mitochondrial localization and functions. In the present study, we show for the first time that endogenous p32 protein is a mitochondrial protein in HeLa cells under control and stress conditions. In defining the impact of altering p32 levels in these cells, we demonstrate that the overexpression of p32 increased mitochondrial fibrils. Conversely, siRNA-mediated p32 knockdown enhanced mitochondrial fragmentation accompanied by a loss of detectable levels of the mitochondrial fusion mediator proteins Mfn (mitofusin) 1 and Mfn2. More detailed ultrastructure analysis by transmission electron microscopy revealed aberrant mitochondrial structures with less and/or fragmented cristae and reduced mitochondrial matrix density as well as more punctate ER (endoplasmic reticulum) with noticeable dissociation of their ribosomes. The analysis of mitochondrial bioenergetics showed significantly reduced capacities in basal respiration and oxidative ATP turnover following p32 depletion. Furthermore, siRNA-mediated p32 knockdown resulted in differential stress-dependent effects on cell death, with enhanced cell death observed in the presence of hyperosmotic stress or cisplatin treatment, but decreased cell death in the presence of arsenite. Taken together, our studies highlight the critical contributions of the p32 protein to the morphology of mitochondria and ER under normal cellular conditions, as well as important roles of the p32 protein in cellular metabolism and various stress responses.

scholarly journals Contrasting roles of GmNAC065 and GmNAC085 in natural senescence, plant development, multiple stresses and cell death responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bruno Paes Melo ◽  
Isabela Tristan Lourenço-Tessutti ◽  
Otto Teixeira Fraga ◽  
Luanna Bezerra Pinheiro ◽  
Camila Barrozo de Jesus Lins ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Development ◽  
Stress Responses ◽  
Regulatory Networks ◽  
Lower Stress ◽  
Multiple Stresses ◽  
Gene Sets ◽  
Ros Accumulation ◽  
Stress Dependent ◽  
Senescence Associated Genes

AbstractNACs are plant-specific transcription factors involved in controlling plant development, stress responses, and senescence. As senescence-associated genes (SAGs), NACs integrate age- and stress-dependent pathways that converge to programmed cell death (PCD). In Arabidopsis, NAC-SAGs belong to well-characterized regulatory networks, poorly understood in soybean. Here, we interrogated the soybean genome and provided a comprehensive analysis of senescence-associated Glycine max (Gm) NACs. To functionally examine GmNAC-SAGs, we selected GmNAC065, a putative ortholog of Arabidopsis ANAC083/VNI2 SAG, and the cell death-promoting GmNAC085, an ANAC072 SAG putative ortholog, for analyses. Expression analysis of GmNAC065 and GmNAC085 in soybean demonstrated (i) these cell death-promoting GmNACs display contrasting expression changes during age- and stress-induced senescence; (ii) they are co-expressed with functionally different gene sets involved in stress and PCD, and (iii) are differentially induced by PCD inducers. Furthermore, we demonstrated GmNAC065 expression delays senescence in Arabidopsis, a phenotype associated with enhanced oxidative performance under multiple stresses, higher chlorophyll, carotenoid and sugar contents, and lower stress-induced PCD compared to wild-type. In contrast, GmNAC085 accelerated stress-induced senescence, causing enhanced chlorophyll loss, ROS accumulation and cell death, decreased antioxidative system expression and activity. Accordingly, GmNAC065 and GmNAC085 targeted functionally contrasting sets of downstream AtSAGs, further indicating that GmNAC85 and GmNAC065 regulators function inversely in developmental and environmental PCD.

scholarly journals Bub1 mediates cell death in response to chromosome missegregation and acts to suppress spontaneous tumorigenesis

2007 ◽  
Vol 179 (2) ◽  
pp. 255-267 ◽  
Author(s):  
Karthik Jeganathan ◽  
Liviu Malureanu ◽  
Darren J. Baker ◽  
Susan C. Abraham ◽  
Jan M. van Deursen
Keyword(s):  
Cell Death ◽  
Chromosome Segregation ◽  
Physiological Role ◽  
Mitotic Checkpoint ◽  
Critical Threshold ◽  
Wild Type ◽  
Checkpoint Protein ◽  
Chromosome Missegregation ◽  
Mitotic Checkpoint Protein

The physiological role of the mitotic checkpoint protein Bub1 is unknown. To study this role, we generated a series of mutant mice with a gradient of reduced Bub1 expression using wild-type, hypomorphic, and knockout alleles. Bub1 hypomorphic mice are viable, fertile, and overtly normal despite weakened mitotic checkpoint activity and high percentages of aneuploid cells. Bub1 haploinsufficient mice, which have a milder reduction in Bub1 protein than Bub1 hypomorphic mice, also exhibit reduced checkpoint activity and increased aneuploidy, but to a lesser extent. Although cells from Bub1 hypomorphic and haploinsufficient mice have similar rates of chromosome missegregation, cell death after an aberrant separation decreases dramatically with declining Bub1 levels. Importantly, Bub1 hypomorphic mice are highly susceptible to spontaneous tumors, whereas Bub1 haploinsufficient mice are not. These findings demonstrate that loss of Bub1 below a critical threshold drives spontaneous tumorigenesis and suggest that in addition to ensuring proper chromosome segregation, Bub1 is important for mediating cell death when chromosomes missegregate.

scholarly journals Pharmaceutical Induction of PGC-1α Promotes Retinal Pigment Epithelial Cell Metabolism and Protects against Oxidative Damage

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Sangeeta Satish ◽  
Hannah Philipose ◽  
Mariana Aparecida Brunini Rosales ◽  
Magali Saint-Geniez
Keyword(s):  
Cell Death ◽  
Antioxidant Enzymes ◽  
Oxidative Damage ◽  
Therapeutic Potential ◽  
Retinal Pigment Epithelial Cell ◽  
Cell Metabolism ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Age Related

Retinal pigment epithelium (RPE) dysfunction due to accumulation of reactive oxygen species and oxidative damage is a key event in the development of age-related macular degeneration (AMD). Here, we examine the therapeutic potential of ZLN005, a selective PGC-1α transcriptional regulator, in protecting RPE from cytotoxic oxidative damage. Gene expression analysis on ARPE-19 cells treated with ZLN005 shows robust upregulation of PGC-1α and its associated transcription factors, antioxidant enzymes, and mitochondrial genes. Energetic profiling shows that ZLN005 treatment enhances RPE mitochondrial function by increasing basal and maximal respiration rates, and spare respiratory capacity. In addition, ZLN005 robustly protects ARPE-19 cells from cell death caused by H2O2, ox-LDL, and NaIO3 without exhibiting any cytotoxicity under basal conditions. ZLN005 protection against H2O2-mediated cell death was lost in PGC-1α-silenced cells. Our data indicates that ZLN005 efficiently protects RPE cells from oxidative damage through selective induction of PGC-1α and its target antioxidant enzymes. ZLN005 may serve as a novel therapeutic agent for retinal diseases associated with RPE dystrophies.

scholarly journals A potential key role for alpha-haemolysin ofStaphylococcus aureusin mediating chondrocyte death in septic arthritis

2018 ◽  
Vol 7 (7) ◽  
pp. 457-467 ◽  
Author(s):  
I. D. M. Smith ◽  
K. M. Milto ◽  
C. J. Doherty ◽  
S. G. B. Amyes ◽  
A. H. R. W. Simpson ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Septic Arthritis ◽  
Cartilage Damage ◽  
Laser Scanning Microscopy ◽  
Cartilage Explants ◽  
Confocal Laser ◽  
Dead Cell ◽  
Chondrocyte Viability ◽  
Chondrocyte Death ◽  
Bovine Cartilage

ObjectivesStaphylococcus aureus (S. aureus) is the most commonly implicated organism in septic arthritis, a condition that may be highly destructive to articular cartilage. Previous studies investigating laboratory and clinical strains of S. aureus have demonstrated that potent toxins induced significant chondrocyte death, although the precise toxin or toxins that were involved was unknown. In this study, we used isogenic S. aureus mutants to assess the influence of alpha (Hla)-, beta (Hlb)-, and gamma (Hlg)-haemolysins, toxins considered important for the destruction of host tissue, on in situ bovine chondrocyte viability.MethodsBovine cartilage explants were cultured with isogenic S. aureus mutants and/or their culture supernatants. Chondrocyte viability was then assessed within defined regions of interest in the axial and coronal plane following live- and dead-cell imaging using the fluorescent probes 5-chloromethylfluorescein diacetate and propidium iodide, respectively, and confocal laser-scanning microscopy.ResultsHla-producing mutants caused substantial chondrocyte death compared with the toxin-deficient control (Hla-Hlb-Hlg-), whilst mutants producing Hlb and Hlg in the absence of Hla induced minimal chondrocyte death. Coronal studies established that Hla-induced chondrocyte death started in the superficial zone of cartilage and spread to deeper layers, whereas Hlb and Hlg toxins were without significant effect.ConclusionThis study identified Hla as a highly potent S. aureus toxin that caused rapid chondrocyte death in bovine cartilage, with other toxins or metabolic products produced by the bacteria playing a minor role. The identification of Hla in mediating chondrocyte death may assist in the development of therapeutic strategies aimed at reducing the extent of cartilage damage during and after an episode of septic arthritis. Cite this article: I. D. M. Smith, K. M. Milto, C. J. Doherty, S. G. B. Amyes, A. H. R. W. Simpson, A. C. Hall. A potential key role for alpha-haemolysin of Staphylococcus aureus in mediating chondrocyte death in septic arthritis. Bone Joint Res 2018;7:457–467. DOI: 10.1302/2046-3758.77.BJR-2017-0165.R1.

scholarly journals 121 SPATIAL CORRELATIONS BETWEEN LOCAL IMPACT STRESS AND CELL DEATH DISTRIBUTIONS

2008 ◽  
Vol 16 ◽  
pp. S65-S66
Author(s):  
C.M. Goreham-Voss ◽  
D.J. McCabe ◽  
M.J. Rudert ◽  
J.A. Martin ◽  
D.R. Pedersen ◽  
...  
Keyword(s):  
Cell Death ◽  
Spatial Correlations ◽  
Impact Stress ◽  
Local Impact

Strain Is the Major Factor for Chondrocyte Death in Articular Cartilage Under Static Load

2003 ◽  
Author(s):  
Amit K. Shah ◽  
Li-Jen Yuan ◽  
Peter A. Torzilli ◽  
C. T. Christopher Chen
Keyword(s):  
Cell Death ◽  
Static Load ◽  
Cell Injury ◽  
Cartilage Explants ◽  
Tunel Staining ◽  
Stress Strain ◽  
Injury Death ◽  
Chondrocyte Death ◽  
Center Region ◽  
Load Removal

Several studies have shown that stress, strain, and stress/strain rate at certain levels can kill chondrocytes, but the major factor is unclear. The objective of this study was to determine the effects of strain and stress on chondrocyte death. Bovine cartilage explants (5 mm) at the age of 2 and 24 month were indented (3 mm) at 3.12, 6.25 and 12.5 MPa to reach a final strain of 15, 30, 45, 60 and 75%. Cell death in the center and on the edges of the indented region was assessed at 0, 3 and 7 days post-loading, and quantified using commercially available software. Our results showed cell death in the center region increased with strain (p<0.001) but decreased with age (p<0.001). Cell death at the edges of the indented region was greater than that of the center (p<0.001), and increased with strain (p<0.001). With post-load incubation, a decrease of cell death was found in the explant loaded with 60 and 75%. Cells with positive TUNEL-staining and positive M30-staining were consistently seen in the middle and deep zones in the center region 3 days after load removal. This suggests that two types of cell injury/death (necrosis and apoptosis) occur simultaneously. Linear regression and ANOVA suggest that strain is the major factor for chondrocyte death under static load.

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

2007 ◽  
Author(s):  
Roman M. Natoli ◽  
Kyriacos A. Athanasiou
Keyword(s):  
Extracellular Matrix ◽  
Cell Death ◽  
Articular Cartilage ◽  
Impact Loading ◽  
Biomechanical Properties ◽  
Cartilage Explants ◽  
Single Impact ◽  
Igf I ◽  
Post Traumatic ◽  
Bioactive Agents

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].

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