Expression characteristics of miR-502-5p/p53/NF-κB signaling pathway in patients with different degrees of knee osteoarthritis: a cross-sectional observational study with methodological limitations
Bibliographic record
Abstract
BACKGROUND AND OBJECTIVE: Knee osteoarthritis (KOA) is a prevalent degenerative joint disease affecting millions worldwide. Recent evidence has demonstrated the crucial role of non-coding RNAs, including microRNAs, in the pathogenesis of musculoskeletal disorders. While previous studies have demonstrated that microRNA-502-5p (miR-502-5p) can protect chondrocytes through p53/NF-κB pathway modulation, its role in human synovial tissue remains unclear. This study aimed to investigate the expression patterns and correlations of the miR-502-5p/p53/NF-κB signaling pathway in KOA synovial tissue across different disease severities. METHODS: This cross-sectional observational study enrolled 80 KOA patients undergoing knee arthroscopy from March 2019 to October 2019, stratified by Kellgren-Lawrence (KL) grades (20 patients per grade). Due to ethical constraints, true healthy control synovial tissue could not be obtained; therefore, synovial samples from 6 KL grade I patients with minimal pathology served as reference controls. Clinical assessments included Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Synovial tissue samples were collected from standardized locations in the suprapatellar pouch during surgery and processed within 2 h. Histopathological analysis was performed using hematoxylin and eosin (HE) staining with Mankin's scoring system. Expression of miR-502-5p and p53/NF-κB pathway components was analyzed using immunofluorescence double-labeling (primary antibodies: anti-p53 1:200, anti-NF-κB p65 1:100, with appropriate negative and isotype controls) and quantitative real-time PCR (qRT-PCR) with U6 as internal control. Sample size for molecular analyses (n = 6 per group) limits statistical power. RESULTS: (1) Clinical scores (VAS, WOMAC) and pathological scores (synovial Mankin's score, cartilage injury score) showed progressive increases with KL grade advancement (all P < 0.01 after Bonferroni correction). Strong positive correlations were observed between clinical symptoms and tissue pathology (r = 0.69-0.87, P < 0.001), though causality cannot be inferred. (2) Immunofluorescence analysis revealed p53 protein expression decreased progressively from reference to severe synovitis (P < 0.05), while TRAF2, NF-κB, IL-1β, TNF-α, and MMP-13 showed opposite trends (all P < 0.05). (3) qRT-PCR demonstrated miR-502-5p mRNA expression increased 2.5-fold in mild, 4.2-fold in moderate, and 3.8-fold in severe synovitis compared to reference tissue (P < 0.001). However, these findings represent associations only and do not establish causal relationships. CONCLUSION: Our findings reveal an association between miR-502-5p upregulation and KOA severity in synovial tissue, contrasting with its reported protective role in chondrocytes. While we observed correlations between miR-502-5p expression, p53 suppression, and NF-κB activation, causal relationships remain unestablished due to lack of functional validation. These results suggest tissue-specific expression patterns that warrant further mechanistic investigation before therapeutic implications can be determined.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".