Fig. 7 | Nature Communications

Fig. 7

From: Excessive mechanical loading promotes osteoarthritis through the gremlin-1–NF-κB pathway

Fig. 7

Gremlin-1 induction by mechanical stress loading occurs through Rac1 activation. a Gremlin-1 mRNA levels in mouse primary chondrocytes treated with 10 µM inhibitors of FAK (PF-573228), ROCK (Y-27632), or RAC1 (NSC23766) 24 h after cyclic tensile strain loading. n = 3 biologically independent samples. *P < 0.05, #P < 0.005 versus stress+, vehicle (one-way ANOVA test). b Gremlin-1 mRNA levels in mouse primary chondrocytes treated with Rac1 inhibitors NSC23766 or EHT1864 at 24 h after cyclic tensile strain loading. n = 3 biologically independent samples. *P < 0.05, #P < 0.005, ##P < 0.001 versus stress + , vehicle (one-way ANOVA test). c Rac1 pull-down activation assay using mouse primary chondrocytes with or without cyclic tensile strain loading. Quantification of densitometry data are shown below, and ratios of positive Rac1 per total Rac1 are shown as fold-increase in the right graph. n = 5 biologically independent samples. *P < 0.05 versus stress– (Student’s unpaired two-tailed t-test). d Gremlin-1 mRNA levels in mouse primary chondrocytes transduced with an adenoviral vector containing Rac1 or GFP. n = 3 biologically independent samples. *P < 0.05 versus GFP (Student’s unpaired two-tailed t-test). e Gremlin-1 mRNA levels in ATDC5 cells lentivirally overexpressing Rac1 or GFP. n = 3 biologically independent samples. *P < 0.05 versus GFP (Student’s unpaired two-tailed t-test). All data are expressed as means ± SD

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