Catabolism of Fibromodulin in Developmental Rudiment and Pathologic Articular Cartilage Demonstrate Novel Roles for MMP-13 and ADAMTS-4 in C-Terminal Processing of SLRPs
Bibliographic record
Abstract
Cartilage regeneration requires a balance of anabolic and catabolic processes. This study examined the susceptibility of fibromodulin (FMOD) and lumican (LUM) to degradation by MMP-13, ADAMTS-4 and ADAMTS-5, the three major degradative proteinases in articular cartilage in osteoarthritis (OA). Immunolocalisation of FMOD and LUM in foot sections of developmental cartilages demonstrated prominent localisations in metatarsal and phalangeal foetal rudiment cartilages and growth plate. An MMP-13 neoepitope antibody (TsYG11) demonstrated localisation of MMP-13 cleaved FMOD in the hypertrophic chondrocytes of the metatarsal growth plate. FMOD was more prominently localised in the superficial cartilage of normal and fibrillated zones in OA cartilage, TsYG11 positive FMOD was located deeper in the cartilage samples. Ab TsYG11 also identified FMOD fragmentation in Western blots of extracts of normal and fibrillated cartilage and total knee replacement OA cartilage.  The C-terminal anti-FMOD used in this study (PR-184) failed to identify FMOD fragmentation due to C terminal processing, an equivalent Ab to the C-terminus of LUM (pAb PR-353) identified 3 prominent LUM fragments in OA human knee cartilages. In-vitro digestion of human knee cartilage with MMP-13, ADAMTS-4 and ADAMTS-5 generated equivalently sized FMOD fragments of 54, 45 and 32kDa to those in blots of OA cartilage, LUM was not less susceptible to fragmention in in-vitro digestions however Ab PR-353 detected N-terminally processed LUM fragments of 39, 38 and 22 kDa in 65-80 year old OA knee cartilage. FMOD and LUM were differentially processed during in-vitro digestions with MMP-13, ADAMTS-4 and ADAMTS-5 with FMOD susceptible to degradation by MMP-13, ADAMTS-4 and to a lesser extent ADAMTS-5 however LUM was less susceptible to fragmentation. FMOD was processed by MMP-13 in metatarsal and phalangeal foetal rudiment developmental cartilages and growth plate indicating a role in skeletogenesis.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".