Fig 2: CircMAPK14-175aa represses the phosphorylation of MAPK14 by competing with MKK6 and subsequently promotes the degradation of FOXC1 via ubiquitination. (A) LEFT panel, total protein from Flag-circMAPK14-175aa transfected HEK293T cells were separated via SDS-PAGE. Right panel, MKK6 was identified by LC-MS analysis. (B) Mutual interaction of Flag-circMAPK14-175aa and MKK6 were confirmed by Co-IP assay. (C) Immunofluorescence colocalisation between Flag-circMAPK14-175aa and MKK6. Blue represent DAPI, green represent Flag-circMAPK14-175aa, red represent MKK6. (D) When the level of 175aa was rose, the amount of MAPK14 but not 175aa binding with MKK6 was apparently reduced by Co-IP assay against MKK6 antibody. (E) The relative expression of FOXC1 mRNA was detected by qRT-PCR after alteration of 175aa level. (F) Upper panel, the relative level of FOXC1 protein was detected by western blotting assay after alteration of 175aa level. Lower panel, the relative level of p-MAPK14 in the nucleus was detected by WB assay after alteration of 175aa level. (G) The time-course experiment with WB assay was conducted after the treatment with cycloheximide (CHX, an inhibitor of protein synthesis). The results of WB assay showed that the ubiquitin-proteasome system (UPS) played major roles in the degradation of FOXC1 after the treatment with (H) MG132 (a proteasome inhibitor). (I) Overexpression of circMAPK14 facilitated the FOXC1 degradation via ubiquitination. (J) The downstream target genes (SOX4, SOX13 and MMP10) levels were correspondingly changed along with the degradation of FOXC1

Fig 3: Taxifolin blocks formation of mucus in TNF-a-induced BEAS-2B cells by inhibiting MMP10 expression. The expressions of MUC5AC and ICAM-1 in TNF-a-induced BEAS-2B cells treated with 50 µM TXL and Oe-MMP10. Data were expressed as mean ± standard deviation (SD). Each experiment was repeated at least three times. ***P < 0.001 Versus Control. ###P < 0.001 Versus TNF-a. ??P<0.01, ???P<0.001 Versus TXL+TNF-a + Oe-NC.

Fig 4: Taxifolin blocks Wnt/ß-catenin pathway by inhibiting MMP10 expression. (a) The levels of apoptosis-related proteins, (b) The expressions of p-GSK3b and b-catenin in TNF-a-induced BEAS-2B cells treated with 50 µM TXL and Oe-MMP10. Data were expressed as mean ± standard deviation (SD). Each experiment was repeated at least three times. ***P < 0.001 Versus Control. ###P < 0.001 Versus TNF-a. ?P<0.05, ??P<0.01, ???P<0.001 Versus TXL+TNF-a + Oe-NC.