Journal: Frontiers in Endocrinology
Article Title: ECM remodeling features in reparative chondrocytes during knee osteoarthritis
doi: 10.3389/fendo.2026.1773139
Figure Lengend Snippet: ECM-related cues promote RepC-associated gene expression and activate TGF-β/SMAD signaling in human articular chondrocytes. (A) Relative mRNA expression levels of RepC-associated genes (CILP, OGN, MMP13, and FRZB) in primary human articular chondrocytes treated with TGF-β1 (5 ng/mL), FN1 (10 μg/mL), or their combination. Gene expression was normalized to internal controls and expressed relative to untreated controls (Con). (B) Quantification of protein expression levels of CILP and MMP13, as well as phosphorylation levels of SMAD2 and SMAD3, under the same treatment conditions as in (A) . Protein levels were normalized to β-actin, and phosphorylation levels were normalized to total SMAD2 or SMAD3, respectively. (C) Representative immunoblot images showing CILP, MMP13, phosphorylated SMAD2 (P-SMAD2), total SMAD2, phosphorylated SMAD3 (P-SMAD3), total SMAD3, and β-actin under control, TGF-β1, FN1, and combined TGF-β1 + FN1 stimulation conditions. Data are presented as mean ± SD from n = 3 independent biological replicates. Statistical significance was determined by one-way ANOVA followed by Tukey’s post hoc multiple-comparison test. **p < 0.01, ***p < 0.001.
Article Snippet: The primary antibodies included CILP (PA5-18553, Thermo Fisher Scientific; 1:1500), MMP13 (18165-1-AP, Proteintech; 1:1000), phospho-SMAD2 (ET1612-32, HUABIO; 1:5000), phospho-SMAD3 (ET1609-41, HUABIO; 1:5000), SMAD2 (12570-1-AP, Proteintech; 1:2000), SMAD3 (66516-1-Ig, Proteintech; 1:2000), and β-actin (66009-1-Ig, Proteintech; 1:20000).
Techniques: Gene Expression, Expressing, Phospho-proteomics, Western Blot, Control, Comparison