N-acylation of glucosamine modulates chondrocyte growth, proteoglycan synthesis, and gene expression.
Bibliographic record
Abstract
OBJECTIVE: To examine the effects of glucosamine (GlcN) and some N-acylated (GlcNAcyl) derivatives on the proliferation and proteoglycan (PG) synthesis of bovine articular chondrocyte (BAC); and to expand these results to human articular chondrocytes (HAC) and study the modulation of gene regulation by these compounds. METHODS: The compounds tested were: glucose (Glc), GlcN.HCl, N-acetyl GlcN (GlcNAc), and N-butyryl GlcN, (GlcNBu). GlcNBu was synthesized from GlcN and butyric anhydride. For the chondrocyte cultures, both anchorage-dependent (AD) and an anchorage-independent (AI) system (alginate beads) were evaluated. Following the various additions, BAC were assessed for total cell number, DNA, or total PG synthesis at different times. Utilizing similar conditions, human cDNA microarrays were performed for the HAC after harvesting total RNA. RESULTS: For AD cultures, the addition of GlcN.HCl (0.1-5.0 mM) to BAC or HAC cultures inhibited cell proliferation and total PG synthesis in a dose-dependent manner. For AI cultures, the inhibitory effects of GlcN.HCl on cell proliferation were less prominent, and PG synthesis increased slightly more for the GlcNAcyl than the GlcN additions. In the AD system, the addition of GlcNAc did not result in the inhibitory effect of GlcN.HCl, while GlcNBu addition resulted in an increase in BAC proliferation and PG synthesis that could not be explained by the Bu moiety alone. For the HAC, additions of 0.1 mM GlcNBu resulted in upregulation of a large number of genes, with only a few downregulated, while GlcN addition resulted in no upregulation and one downregulated gene, for preset stringency criteria. CONCLUSION: Addition of GlcNBu to BAC or HAC to AD cultures generally stimulated cell proliferation and PG synthesis, while addition of GlcN resulted in inhibition of these indicators. The inhibitory effects of the GlcN molecule appear to be related to the unsubstituted amino group. Additions of GlcNBu, but not GlcN, to HAC resulted in upregulation in the expression of a large number of genes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".