It has been demonstrated that the activated NF B will translocate into nucleus and induce the transcriptional activation of anti apoptosis genes, like c IAP1 and c IAP2. Consistently, we observed a prominent nuclear trans location of NF B in the TNF treated NC transfectants. However, transfection with miR 26b efficiently blocked selleck chemicals EPZ-5676 the TNF induced NF B nuclear translocation in both QGY 7703 and MHCC 97H cells. Furthermore, TNF stimulation upreg ulated the mRNA levels of c IAP1 and c IAP2 in the NC transfectants, but this effect was significantly abrogated by the transfection of miR 26b. Next, the influence of miR 26b on the signaling mole cules of NF B pathway was investigated. As reported, TNF treatment significantly increased the phosphor ylation of IB and p65 in control cells, suggesting the activation of NF B signaling.
Notably, the TNF induced phosphorylation of IB and p65 was much less evident in the miR 26b transfectants, compared with the control cells. In con trast, the antagonism of endogenous miR 26b by anti miR 26b enhanced the TNF stimulated NF B signaling. Collectively, these data indicate that miR 26b may sup press NF B signaling by attenuating the phosphoryl ation of IB and p65. Inhibitors,Modulators,Libraries TAK1 and TAB3 are direct targets of miR 26b As mentioned above, TAK1 and TAB3 are the upstream positive regulators of the NF B pathway and their 3UTRs contain putative miR 26b binding sites, as predicted by TargetScan. We therefore examined whether TAK1 and TAB3 were direct targets of miR 26b which mediated the suppressive effect of miR 26b on NF B signaling.
Inhibitors,Modulators,Libraries Inhibitors,Modulators,Libraries As shown, knockdown of either TAK1 or TAB3 gene by small interfering RNA abated the TNF induced activity of NF B reporter and phosphorylation of IB and p65, which mimicked the effect of miR 26b overexpression in the same cell models. Furthermore, dual luciferase reporter analysis showed that the co expression of miR 26b significantly in hibited the activity of Inhibitors,Modulators,Libraries firefly luciferase that carried the wild type but not mutant 3UTR of TAK1 or TAB3, indicating that miR 26b may suppress gene expression through its binding sequences at the Inhibitors,Modulators,Libraries 3UTR of TAK1 and TAB3. Next, the effect of miR 26b on the endogenous cellular expression of its potential tar gets was examined. The results revealed that the introduc tion of miR 26b diminished the expression selleck chemicals of TAK1 and TAB3 at their protein but not mRNA levels, whereas the antagonism of endogenous miR 26b expression increased the protein levels of TAK1 and TAB3. All together, these data imply that miR 26b may re press the expression of TAK1 and TAB3 by binding to their 3UTR and thus blocking NF B signaling.