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. 2021 Apr 7;16(4):e0249544. doi: 10.1371/journal.pone.0249544

Fig 3. Effect of NF-κB inhibition on MMP-9 induced increase in Caco-2 TJ permeability and increase in MLCK expression.

Fig 3

(A) NF-κB p65 siRNA transfection prevented the MMP-9-induced drop in Caco-2 TER and (B) increase in dextran 10 kDa flux (n = 4). *** P < 0.001 vs control; ## P < 0.01 vs MMP-9 treatment; **** P < 0.0001 vs control; #### P < 0.0001 vs MMP-9 treatment. (C) MMP-9 treatment resulted in a significant increase in NF-κB target gene IL-8. NF-κB p65 siRNA prevented the IL-8 production by Caco-2 monolayers after MMP-9 treatment (24 hrs). IL-8 secretion was determined by collecting and centrifuging the media and then assayed by ELISA-based kit. *** P < 0.0001 vs control; ### P < 0.001 vs. MMP-9 treatment. (D) Knocking-down NF-κB p65 inhibited the MMP-9 induced increase in MLCK protein expression as assessed by western blot analysis. (NT; non-target siRNA). (E) Silencing p38 kinase by siRNA transfection prevented the MMP-9-induced activation of NF-κB p65 as assessed by phosphorylation of p65. Caco-2 monolayers were transfected with p38 kinase siRNA for a 72-hr time period and then treated with MMP-9 for 1 hr, (NT; not-target siRNA).