Multiple changes in gene expression in chronic human Achilles tendinopathy

Abstract

TMŽ . Atlas cDNA cell interaction arrays CLONTECH were used to examine degenerate tissue from four patients with Achilles tendon disorders, in order to identify changes in expression of genes important in cell᎐cell and cell᎐matrix Ž . interactions. The greatest difference between normal post-mortem and degenerate tissue samples was in the level of MMP-3 Ž . stromelysin mRNA, which was down-regulated in all the degenerate samples. Quantitative RT-PCR assay of RNA extracted from paired 'normal' and degenerate Achilles tendon tissue samples taken from tendons during surgery mirrored the results of the arrays. Levels of MMP-3 mRNA were lower, whereas levels of type-I and type-III collagen mRNAs were significantly higher, in the degenerate compared to the 'normal' samples. Immunoblotting of proteins extracted from the same tendon samples showed that three of four normal tissue samples taken from individuals without apparent tendon disorder had much higher levels of MMP-3 protein than 'normal' or degenerate samples from patients with tendinosis. We suggest that MMP-3 may play an important role in the regulation of tendon extracellular matrix degradation and tissue remodelling. ᮊ

Ciprofloxacin enhances the stimulation of matrix metalloproteinase 3 expression by interleukin‐1β in human tendon‐derived cells

“…The level of MMP activity in a tissue can be regulated by changes in gene expression, by the cleavage of latent MMP precursors, and by association of the MMP with inhibitory proteins (11). We have previously described differences in the expression of certain MMPs between normal and degenerate human tendons, consistent with a role in tendon pathology (12).…”

“…Tendon pain and degeneration have been associated with an increase in the normal turnover of matrix proteins (9,10,12). MMP-3 has a broad substrate specificity; it is able to degrade matrix components including type III collagen and the proteoglycans aggrecan and versican, and is capable of activating a variety of other MMPs and pro-tumor necrosis factor (11).…”

“…However, its role in tendon physiology and pathology has not been clearly defined. In tendons from sites exposed to high mechanical demands, such as the Achilles and supraspinatus tendons, the expression and activity of MMP-3 are high compared with that in normal flexor tendons (10,12). This activity may be necessary for the maintenance of the matrix in response to repeated microinjury; a change in the activity of several MMPs has also been associated with tendon rupture (10).…”

“…The RNA was stored at Ϫ70°C as aliquots, which were thawed only once, and was assayed for GAPDH, MMP-1, MMP-2, and MMP-3 messenger RNA (mRNA) using one-step RT-PCR reactions in a GeneAmp 5700 (Applied Biosystems). All primers and probes have been described previously (12). Standard curves were run in each assay using freshly diluted aliquots of pooled tendon-cell RNA.…”

Modulation of aggrecan and ADAMTS expression in ovine tendinopathy induced by altered strain

“…shown that a number of molecular changes occur within the diseased tendon, including altered content and expression of collagen and proteoglycan (PG) and expression of matrix-degrading enzymes (6)(7)(8)(9)(10)(11)(12)(13)(14). However, which if any of these changes precede and lead to rupture, and which are a consequence of tearing is unknown.…”