scholarly journals The ciliary protein IFT88 controls post-natal cartilage thickness and influences development of osteoarthritis

2020 ◽  
Author(s):  
CR Coveney ◽  
L Zhu ◽  
J Miotla-Zarebska ◽  
B Stott ◽  
I Parisi ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Cell Biology ◽  
Articular Chondrocytes ◽  
Skeletal Development ◽  
Cartilage Degradation ◽  
Cartilage Thickness ◽  
Tissue Growth ◽  
Calcified Cartilage ◽  
Health And Disease

AbstractMechanical forces are known to drive cellular signalling programmes in cartilage development, health, and disease. Proteins of the primary cilium, implicated in mechanoregulation, control cartilage formation during skeletal development, but their role in post-natal cartilage is unknown. Ift88fl/fl and AggrecanCreERT2 mice were crossed to create a cartilage specific inducible knockout mouse AggrecanCreERT2;Ift88fl/fl. Tibial articular cartilage thickness was assessed, through adolescence and adulthood, by histomorphometry and integrity by OARSI score. In situ cell biology was investigated by immunohistochemistry (IHC) and qPCR of micro-dissected cartilage. OA was induced by destabilisation of the medial meniscus (DMM). Some mice were provided with exercise wheels in their cage. Deletion of IFT88 resulted in a reduction in medial articular cartilage thickness (atrophy) during adolescence from 102.57μm, 95% CI [94.30, 119.80] in control (Ift88fl/fl) to 87.36μm 95% CI [81.35, 90.97] in AggrecanCreERT2;Ift88fl/fl by 8-weeks p<0.01, and adulthood (104.00μm, 95% CI [100.30, 110.50] in Ift88fl/fl to 89.42μm 95% CI [84.00, 93.49] in AggrecanCreERT2;Ift88fl/fl, 34-weeks, p<0.0001) through a reduction in calcified cartilage. Thinning in adulthood was associated with spontaneous cartilage degradation. Following DMM, AggrecanCreERT2;Ift88fl/fl mice had increased OA (OARSI scores at 12 weeks Ift88fl/fl = 22.08 +/− 9.30, and AggrecanCreERT2;Ift88fl/fl = 29.83 +/− 7.69). Atrophy was not associated with aggrecanase-mediated destruction or chondrocyte hypertrophy. Ift88 expression positively correlated with Tcf7l2 and connective tissue growth factor. Cartilage thickness was restored in AggrecanCreERT2;Ift88fl/fl by voluntary wheel exercise. Our results demonstrate that ciliary IFT88 regulates cartilage thickness and is chondroprotective, potentially through modulating mechanotransduction pathways in articular chondrocytes.

scholarly journals Chondrocyte heterogeneity: immunohistologically defined variation of integrin expression at different sites in human fetal knees.

1995 ◽  
Vol 43 (4) ◽  
pp. 447-457 ◽  
Author(s):  
D M Salter ◽  
J L Godolphin ◽  
M S Gourlay
Keyword(s):  
Articular Cartilage ◽  
Growth Plate ◽  
Articular Chondrocytes ◽  
Knee Joints ◽  
Matrix Composition ◽  
Epiphyseal Growth Plate ◽  
Surface Receptors ◽  
Cartilage Differentiation ◽  
Health And Disease ◽  
And Function

During development and at maturity different forms of cartilage vary in morphology and macromolecular content. This reflects heterogeneity of chondrocyte activity, in part involving differential interactions with the adjacent extracellular matrix via specialized cell surface receptors such as integrins. We undertook an immunohistological study on a series of human fetal knee joints to assess variation in the expression of integrins by chondrocytes and potential matrix ligands in articular, epiphyseal, growth plate, and meniscal cartilage. The results show that articular chondrocytes (beta 1+, beta 5 alpha V+, alpha 1+, alpha 2+/-, alpha 5+, weakly alpha 6+, alpha V+) differed from epiphyseal (beta 1+, beta 5 alpha V+, alpha 1+/-, alpha 2+/-, alpha 5+, alpha 6+, alpha V+) growth plate (beta 1+, beta 5 alpha V+, alpha 1-, alpha 2-, alpha 5+, alpha 6+, alpha V+), and meniscal cells (beta 1+, beta 5 alpha V+, alpha 1+, strongly alpha 2+, alpha 5+, alpha 6+, alpha V+ in expression of integrin subunits. There was no expression of beta 3, beta 4, beta 6, or alpha 3 by chondrocytes. These results differ from previous reports on the expression of integrins by adult articular cartilage, where alpha 2 and alpha 6 are not seen. Variation in distribution of matrix ligands was also seen. Fibronectin, laminin and Type VI collagen were expressed in all cartilages but there was restricted expression of tenascin, ED-A and ED-B fibronectin isoforms (articular cartilage and meniscus), and vitronectin (absent from growth plate cartilage). Regulated expression of integrins by chondrocytes, associated with changes in the pericellular matrix composition, is of potential importance in control of cartilage differentiation and function in health and disease.

A comparative study of articular cartilage thickness in the stifle of animal species used in human pre-clinical studies compared to articular cartilage thickness in the human knee

2006 ◽  
Vol 19 (03) ◽  
pp. 142-146 ◽  
Author(s):  
D. D. Frisbie ◽  
M. W. Cross ◽  
C. W. McIlwraith
Keyword(s):  
Articular Cartilage ◽  
Subchondral Bone ◽  
Clinical Studies ◽  
Femoral Condyle ◽  
Cartilage Thickness ◽  
Bone Plate ◽  
Subchondral Bone Plate ◽  
Femoral Trochlea ◽  
Human Knee ◽  
Calcified Cartilage

SummaryHistological measurements of the thickness of non-calcified and calcified cartilage, as well as the subchondral bone plate in five locations on the femoral trochlea and medial femoral condyles of species were used in preclinical studies of articular cartilage and compared to those of the human knee. Cadaver specimens were obtained of six human knees, as well as six equine, six goat, six dog, six sheep and six rabbit stifle joints (the animal equivalent of the human knee). Specimens were taken from the lateral trochlear ridge, medial trochlear ridge and medial femoral condyle. After histopathological processing, the thickness of non-calcified and calcified cartilage layers, as well as the subchondral bone plate, was measured. Average articular cartilage thickness over five locations were 2.2–2.5 mm for human, 0.3 mm for rabbit, 0.4–0.5 mm for sheep, 0.6–1.3 mm for dog, 0.7–1.5 mm for goat and 1.5–2 mm for horse. The horse provides the closest approximation to humans in terms of articular cartilage thickness, and this approximation is considered relevant in pre-clinical studies of cartilage healing.

scholarly journals Aging, Cell Senescence, the Pathogenesis and Targeted Therapies of Osteoarthritis

2021 ◽  
Vol 12 ◽  
Author(s):  
Xin-Xin Zhang ◽  
Shi-Hao He ◽  
Xu Liang ◽  
Wei Li ◽  
Tian-Fang Li ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Cellular Senescence ◽  
Articular Chondrocytes ◽  
Cartilage Degradation ◽  
Cell Senescence ◽  
Joint Disease ◽  
Epigenetic Alterations ◽  
New Agents ◽  
Key Factor ◽  
Long Time

Osteoarthritis (OA) is a chronic, debilitating joint disease characterized by progressive destruction of articular cartilage. For a long time, OA has been considered as a degenerative disease, while recent observations indicate the mechanisms responsible for the pathogenesis of OA are multifaceted. Aging is a key factor in its development. Current treatments are palliative and no disease modifying anti-osteoarthritis drugs (DMOADs) are available. In addition to articular cartilage degradation, cellular senescence, synovial inflammation, and epigenetic alterations may all have a role in its formation. Accumulating data demonstrate a clear relationship between the senescence of articular chondrocytes and OA formation and progression. Inhibition of cell senescence may help identify new agents with the properties of DMOADs. Several anti-cellular senescence strategies have been proposed and these include sirtuin-activating compounds (STACs), senolytics, and senomorphics drugs. These agents may selectively remove senescent cells or ameliorate their harmful effects. The results from preclinical experiments and clinical trials are inspiring. However, more studies are warranted to confirm their efficacy, safety profiles and adverse effects of these agents.

scholarly journals Interleukin-26 Has Synergistic Catabolic Effects with Palmitate in Human Articular Chondrocytes via the TLR4-ERK1/2-c-Jun Signaling Pathway

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2500
Author(s):  
Yi-Ting Chen ◽  
Chih-Chien Wang ◽  
Chia-Pi Cheng ◽  
Feng-Cheng Liu ◽  
Chian-Her Lee ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Inflammatory Arthritis ◽  
Articular Chondrocytes ◽  
Saturated Fatty Acids ◽  
Signal Transduction Pathway ◽  
Cartilage Degradation ◽  
Cartilage Matrix ◽  
Human Articular Chondrocytes ◽  
Cox 2 ◽  
Interleukin 26

The inflammatory cytokine interleukin-26 (IL-26) is highly expressed in the serum and synovial fluid of patients with inflammatory arthritis. The effect of IL-26 on human articular chondrocytes (HACs) remains unclear. Obesity is associated with disability of patients with rheumatoid arthritis and disease activity in those with ankylosing spondylitis. The saturated free fatty acid palmitate with IL-1β can synergistically induce catabolic effects in HACs. The aim of this study was to evaluate the effects of IL-26 and palmitate in HACs. In this study, palmitate markedly synergizes the IL-26-induced proinflammatory effects and matrix protease, including COX-2, IL-6, and MMP-1, in HACs via the toll-like receptor 4 (TLR4)-ERK1/2-c-Jun signal transduction pathway. The synergistic catabolic effects of palmitate and IL-26 were attenuated by inhibitors of TLR4 (TAK242), ERK1/2 (U0126), or c-Jun (SP600125) in HACs and cartilage matrix. In addition, metformin, a potential inhibitor of TLR4, also decreased expression of COX-2 and IL-6 induced by co-incubation with IL-26 and palmitate. IL-26 and palmitate synergistically induced expression of inflammatory and catabolic mediators, resulting in articular cartilage matrix breakdown. The present study also revealed a possible mechanism and therapeutic targets against articular cartilage degradation by increased saturated fatty acids in patients with inflammatory arthritis.

Tetrapolar Measurement of Electrical Conductivity and Thickness of Articular Cartilage

2004 ◽  
Vol 126 (4) ◽  
pp. 475-484 ◽  
Author(s):  
J. S. Binette ◽  
M. Garon ◽  
P. Savard ◽  
M. D. McKee ◽  
M. D. Buschmann
Keyword(s):  
Electrical Conductivity ◽  
Articular Cartilage ◽  
Subchondral Bone ◽  
Articular Surface ◽  
Cartilage Thickness ◽  
Therapeutic Interventions ◽  
Bovine Articular Cartilage ◽  
Calcified Cartilage ◽  
Non Destructive

A tetrapolar method to measure electrical conductivity of cartilage and bone, and to estimate the thickness of articular cartilage attached to bone, was developed. We determined the electrical conductivity of humeral head bovine articular cartilage and subchondral bone from a 1- to 2-year-old steer to be 1.14±0.11S/m(mean±sd,n=11) and 0.306±0.034S/m,(mean±sd,n=3), respectively. For a 4-year-old cow, articular cartilage and subchondral bone electrical conductivity were 0.88±0.08S/m(mean±sd,n=9) and 0.179±0.046S/m(mean±sd,n=3), respectively. Measurements on slices of cartilage taken from different distances from the articular surface of the steer did not reveal significant depth-dependence of electrical conductivity. We were able to estimate the thickness of articular cartilage with reasonable precision (<20% error) by injecting current from multiple electrode pairs with different inter-electrode distances. Requirements for the precision of this method to measure cartilage thickness include the presence of a distinct layer of calcified cartilage or bone with a much lower electrical conductivity than that of uncalcified articular cartilage, and the use of inter-electrode distances of the current injecting electrodes that are on the order of the cartilage thickness. These or similar methods present an attractive approach to the non-destructive determination of cartilage thickness, a parameter that is required in order to estimate functional properties of cartilage attached to bone, and evaluate the need for therapeutic interventions in arthritis.

Biophysics (and sociology) of ceramides.

2005 ◽  
Vol 72 ◽  
pp. 177-188 ◽  
Author(s):  
Félix M. Goñi ◽  
F-Xabier Contreras ◽  
L-Ruth Montes ◽  
Jesús Sot ◽  
Alicia Alonso
Keyword(s):  
Cell Biology ◽  
Positive Curvature ◽  
Acyl Chain ◽  
Cell Signalling ◽  
Hexagonal Structure ◽  
Lipid Monolayer ◽  
Flip Flop ◽  
Long Chain ◽  
Bilayer Permeability

In the past decade, the long-neglected ceramides (N-acylsphingosines) have become one of the most attractive lipid molecules in molecular cell biology, because of their involvement in essential structures (stratum corneum) and processes (cell signalling). Most natural ceramides have a long (16-24 C atoms) N-acyl chain, but short N-acyl chain ceramides (two to six C atoms) also exist in Nature, apart from being extensively used in experimentation, because they can be dispersed easily in water. Long-chain ceramides are among the most hydrophobic molecules in Nature, they are totally insoluble in water and they hardly mix with phospholipids in membranes, giving rise to ceramide-enriched domains. In situ enzymic generation, or external addition, of long-chain ceramides in membranes has at least three important effects: (i) the lipid monolayer tendency to adopt a negative curvature, e.g. through a transition to an inverted hexagonal structure, is increased, (ii) bilayer permeability to aqueous solutes is notoriously enhanced, and (iii) transbilayer (flip-flop) lipid motion is promoted. Short-chain ceramides mix much better with phospholipids, promote a positive curvature in lipid monolayers, and their capacities to increase bilayer permeability or transbilayer motion are very low or non-existent.

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