Fig. 3

Concentration-dependent effect of native human proteoglycan 4 (nhPRG4) on agonist-induced activation of toll-like receptors 2 and 4 (TLR2 and TLR4) expressing human embryonic kidney (TLR2-HEK and TLR4-HEK) cells. Absorbance values across groups were normalized to untreated cells (control). Data represents the mean ± SD from four independent experiments. a Inhibition of Pam3CSK4-induced activation of TLR2 by nhPRG4 treatment. Pam3CSK4 significantly activated TLR2. nhPRG4 (50, 100 and 150 μg/mL) co-incubation significantly reduced Pam3CSK4-induced TLR2 activation. nhPRG4 (100 and 150 μg/mL) treatments were more efficacious in reducing TLR2 activation than nhPRG4 (50 μg/mL). nhPRG4 alone did not stimulate TLR2; *p <0.001. b Inhibition of lipopolysaccharide (LPS)-induced activation of TLR4 by nhPRG4 treatment. LPS significantly activated TLR4. nhPRG4 (50, 100 and 150 μg/mL) co-incubation significantly reduced LPS-induced TLR4 activation. nhPRG4 (100 and 150 μg/mL) treatments were more efficacious in reducing TLR4 activation than nhPRG4 (50 μg/mL). nhPRG4 (150 μg/mL) treatment was more efficacious in reducing TLR4 activation than nhPRG4 (100 μg/mL). nhPRG4 alone did not stimulate TLR4; *p <0.001, **p <0.01, ***p <0.05