Table 2.
Effect of age on articular cartilage protein half-lives.
| Protein name | Number of peptides | Fold-change (90 wk:25 wk) | Mean difference ( ) |
95% CI of difference ( ) |
P-value | |
|---|---|---|---|---|---|---|
| Proteoglycans | ||||||
| ACAN | 4 | 22.0 | 22.1 | [-89.9, 134.1] | 0.6665 | |
| ASPN* | 2 | 0.54 | -1.44 | [-4.40, 1.52] | 0.3245 | |
| BGN* | 6 | 1.52 | 0.88 | [-1.97, 3.72] | 0.5079 | |
| DCN* | 6 | 1.54 | 0.027 | [0.012, 0.042] | 0.0022# | |
| FMOD* | 3 | 1.93 | 7.15 | [-98.3, 112.6] | 0.8820 | |
| FN1 | 6 | 2.27 | 0.11 | [0.050, 0177] | 0.0026# | |
| LUM* | 4 | 1.34 | 0.029 | [0.003, 0.054] | 0.0325 | |
| OGN* | 2 | 88.0 | 137 | [-3942, 4216] | 0.9411 | |
| PRELP | 4 | 1.70 | 0.27 | [-0.033, 0.58] | 0.0749 | |
| PRG4 | 4 | 1.72 | 0.024 | [0.018, 0.030] | <0.0001# | |
| Collagens | ||||||
| COL1A1 | 2 | 45.0 | 135 | [-1232, 1503] | 0.8276 | |
| COL2A1 | 4 | – | – | – | – | |
| COL6A1 | 12 | – | – | – | – | |
| COL6A2 | 7 | 2 | 121 | [-2142, 2384] | 0.9105 | |
| COL6A3 | 15 | 1.57 | 6.00 | [-40.2, 52.2] | 0.7787 | |
| COL9A1 | 4 | – | – | – | – | |
| COL11A1 | 2 | – | – | – | – | |
| COL12A1 | 4 | – | – | – | – | |
| ECM-related | ||||||
| CHAD | 4 | 46.0 | 277 | [-1152, 1695] | 0.6766 | |
| CHIL3 | 2 | 1.08 | 0.008 | [-0.061, 0.078] | 0.7965 | |
| CILP | 3 | 1.69 | 0.091 | [-0.129, 0.310] | 0.3906 | |
| CLU | 3 | 2.93 | 0.139 | [0.077, 0.200] | 0.0006# | |
| COMP | 2 | 2.33 | 0.117 | [0.046, 0.187] | 0.0045# | |
| LMNA | 7 | 1.12 | 0.008 | [-0.012, 0.028] | 0.3780 | |
| MATN1 | – | – | – | – | – | |
| MATN3 | 4 | 1.56 | 0.114 | [-0.031, 0.259] | 0.1153 | |
| MFGE8 | 5 | 0.78 | -0.055 | [-0.490, 0.380] | 0.7833 | |
| SPP1 | 3 | – | – | – | – | |
| THBS1 | 3 | 3.67 | 0.660 | [-0.328, -1.65] | 0.1650 | |
| VTN | 3 | 2.84 | 0.436 | [0.030, 0.842] | 0.0379 | |
Protein half-lives were calculated from the decay constant for each protein obtained from d2ome software. Mean difference was calculated as 90-wk minus 25-wk values. Comparison between groups was performed using paired t-test (two-tailed) with Welch's correction.
*
Small leucine-rich proteoglycans (SLRPs).
#
P<<0.05i > following Benjamini–Hochberg FDR correction for multiple comparisons. Proteins that did not incorporate deuterium within the 60-d labeling duration are indicated by a dash.