Effect of NOV knockdown on cytokine-stimulated MMP-2/-9 activities and CCL2 concentration in DRG neuronal cultures. Experiments were performed 48 hours following transfection of primary sensory neurons with a control non-silencing siRNA (Ctr) or a specific NOV siRNA (siNOV). (A) Upper panel, representative gelatin zymograph showing MMP-9 and MMP-2 enzymatic activities after transfection and treatment for 24 hours with cytokines TNF-α (1 ng/ml) or IL-1β (1 ng/ml). Lower panel, quantification of MMP-9 and MMP-2 gelatinolytic bands. Data represent the mean of four values ± SEM (ns, not significant, *P < 0.05 cytokine versus not treated (NT), †P < 0.05 siNOV versus Ctr). (B, C) CCL2 protein levels produced in conditioned medium of cultured DRG after transfection and exposure to cytokines TNF-α (1 ng/ml) (B) or IL-1β (1 ng/ml) (C) for 24 hours (or no treatment, NT) determined by ELISA. Data represent the mean of four values in a representative experiment performed at least two times with similar results (* P < 0.05 IL-1β or TNF-α versus NT. † P < 0.05 siNOV versus Ctr).