scholarly journals Preferential mRNA expression of prostromelysin relative to procollagenase and in situ localization in human articular cartilage.

1992 ◽  
Vol 89 (4) ◽  
pp. 1189-1197 ◽  
Author(s):  
Q Nguyen ◽  
J S Mort ◽  
P J Roughley
Keyword(s):  
Articular Cartilage ◽  
Mrna Expression ◽  
Human Articular Cartilage

scholarly journals Versican gene expression in human articular cartilage and comparison of mRNA splicing variation with aggrecan

1993 ◽  
Vol 291 (2) ◽  
pp. 361-367 ◽  
Author(s):  
J Grover ◽  
P J Roughley
Keyword(s):  
Alternative Splicing ◽  
Articular Cartilage ◽  
Regulatory Protein ◽  
Mrna Splicing ◽  
Human Articular Cartilage ◽  
Complement Regulatory Protein ◽  
Mature Adult ◽  
Epidermal Growth ◽  
Egf Domain

The chondrocytes in human articular cartilage from subjects of all ages express mRNAs for both of the aggregating proteoglycans aggrecan and versican, although the level of expression of versican mRNA is much lower than that of aggrecan mRNA. Aggrecan shows alternative splicing of the epidermal growth factor (EGF)-like domain within its C-terminal globular region, but there is no evidence for a major difference in situ in the relative expression of this domain with age. At all ages studied from birth to the mature adult, a greater proportion of transcripts lacked the EGF domain. The relative proportions of the two transcripts did not change upon culture and passage of isolated chondrocytes. In contrast, the neighbouring complement regulatory protein (CRP)-like domain was predominantly expressed irrespective of age, but cell culture did result in variation of the splicing of this domain. Versican possesses two EGF-like domains and one CRP-like domain, but at all ages the three domains were predominantly present in all transcripts. This situation persisted upon culture and passage of the chondrocytes. Thus, unlike aggrecan, the versican expressed by human articular cartilage does not appear to undergo alternative splicing of its C-terminal globular region, either in cartilage in situ or in chondrocytes in culture.

Functional in situ assessment of human articular cartilage using MRI: a whole-knee joint loading device

2017 ◽  
Vol 16 (6) ◽  
pp. 1971-1986 ◽  
Author(s):  
Sven Nebelung ◽  
Manuel Post ◽  
Stefan Raith ◽  
Horst Fischer ◽  
Matthias Knobe ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Knee Joint ◽  
Human Articular Cartilage ◽  
Joint Loading ◽  
Loading Device ◽  
In Situ Assessment ◽  
Knee Joint Loading

scholarly journals The action of human articular-cartilage metalloproteinase on proteoglycan and link protein. Similarities between products of degradation in situ and in vitro

1986 ◽  
Vol 237 (1) ◽  
pp. 117-122 ◽  
Author(s):  
I K Campbell ◽  
P J Roughley ◽  
J S Mort
Keyword(s):  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Interleukin 1 ◽  
Human Articular Cartilage ◽  
Link Protein ◽  
Protein Components ◽  
Stimulation Of ◽  
Hyaluronic Acid Binding

Interleukin 1 stimulation of human articular cartilage in organ culture produced the concomitant release of proteoglycan fragments and latent metalloproteinase. The released fragments ranged in size from that of almost intact proteoglycan subunits to the product of limiting digestion generated by the activated metalloproteinase. None of the fragments possessed the ability to interact with hyaluronic acid. Analysis of proteoglycan aggregate digested with the activated metalloproteinase showed that isolated hyaluronic acid-binding regions were produced from the proteoglycan subunits, and that the two higher-Mr link-protein components (Mr 48,000 and 44,000) were converted into the lowest-Mr component (Mr 41,000). Link protein extracted from cartilage under stimulation with interleukin 1 showed a similar conversion. These results suggest that interleukin 1 stimulates the release of latent metalloproteinase from chondrocytes and that a proportion of the enzyme is activated in situ in the cartilage matrix. The mode of action of the activated enzyme is compatible with a role in the changes in proteoglycan structure seen in aging.

The Inhomogeneous Mechanical Properties of the Pericellular Matrix of Articular Cartilage Measured In Situ by Atomic Force Microscopy

2009 ◽  
Author(s):  
Rebecca E. Wilusz ◽  
Eric M. Darling ◽  
Michael P. Bolognesi ◽  
Stefan Zauscher ◽  
Farshid Guilak
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Articular Cartilage ◽  
Biomechanical Properties ◽  
Human Articular Cartilage ◽  
Pericellular Matrix ◽  
Force Microscopy ◽  
Narrow Region ◽  
Atomic Force

Articular cartilage is the connective tissue that lines the articulating surfaces of diarthrodial joints, providing a low-friction, load-bearing surface during joint motion. Articular cartilage comprises of a single cell type, the chondrocyte, embedded within an extensive extracellular matrix (ECM). Each chondrocyte is surrounded by a narrow region called the pericellular matrix (PCM) that is distinct from the ECM in both its biochemical composition [1] and biomechanical properties [2]. While multiple techniques have been used to measure the mechanical properties of the PCM, including micropipette aspiration of isolated chondrons [2], these studies required mechanical or enzymatic extraction of the chondrocyte and surrounding PCM (i.e., the “chondron” [1]) from the cartilage, and the influence of this isolation process on PCM properties is unknown. Atomic force microscopy (AFM) provides a high resolution form of nano- and microindentation approaches that can be used to measure local mechanical properties in situ [3,4]. The objective of this study was to use AFM to quantify the biomechanical properties of the ECM and PCM of human articular cartilage in situ.

scholarly journals Quantification of aggrecan and link-protein mRNA in human articular cartilage of different ages by competitive reverse transcriptase-PCR

1996 ◽  
Vol 319 (2) ◽  
pp. 489-498 ◽  
Author(s):  
Mark C BOLTON ◽  
Jayesh DUDHIA ◽  
Michael T BAYLISS
Keyword(s):  
Articular Cartilage ◽  
Reverse Transcriptase ◽  
Mrna Expression ◽  
Northern Hybridization ◽  
Human Articular Cartilage ◽  
Rt Pcr ◽  
Link Protein ◽  
Reverse Transcriptase Pcr ◽  
Age Related ◽  
Age Related Changes

A competitive reverse transcriptase–PCR (RT-PCR) assay has been developed for the quantification of particular mRNA species in human articular cartilage. Competitor RNA species were synthesized that differed from the amplified target sequence only by the central insertion of an EcoRI restriction site. By using known amounts of synthetic target and competitor RNA, it was shown that competitor RNA molecules designed in this way are reverse-transcribed and amplified with equal efficiency to the target of interest. Furthermore quantification could be performed during the plateau phase of the PCR, which was necessary when using ethidium bromide fluorescence as a detection system. The inhibition of aggrecan and link-protein mRNA expression by interleukin 1 or tumour necrosis factor in monolayers of human articular chondrocytes quantified by this competitive RT-PCR method compared favourably with Northern hybridization studies. The main advantage of this technique is that it can be used to quantify levels of mRNA with RNA extracted directly from 100 mg wet weight of human articular cartilage. Age-related changes in aggrecan and link-protein mRNA were therefore quantified in human articular cartilage directly after dissection from the joint. The concentration of link-protein mRNA was higher in immature cartilage than in mature cartilage when expressed relative to the amount of glyceraldehyde-3-phosphate dehydrogenase mRNA, but no age-related changes were observed in aggrecan mRNA expression. The ratio of aggrecan to link-protein mRNA was higher in mature cartilage than in immature tissue. These age-related differences in the molecular stoichiometry of aggrecan and link-protein mRNA might have implications with respect to the regulation of the formation and the stability of the proteoglycan aggregates in cartilage.

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