Fig. 8.

Effects of PBA ER stress inhibitor on GRP78 protein levels and caspase-12 activity. T3 modulates the expression level of EndoR molecular chaperone GRP78. HeLa cells were treated with α-T3, γ-T3, δ-T3, or TRF (10 μg/ml) for 24 h. CC indicates the treatment with the vehicle only (DMSO). Tunicamycin (TM) (5 μg/ml, for 4 h) was used as a positive control of EndoR stress induction. 4-PBA was used as the specific inhibitor of EndoR stress. α-Tubulin was utilized as a loading control. a GRP78 protein levels are affected by T3 treatment, and the co-treatment with 4-PBA (5 mM) prevents the changes induced by T3. The figures show one representative experiment out of at least three separate experiments. Data obtained by densitometry were log₂ transformed in order to obtain data symmetrically distributed and were analyzed by one-way ANOVA with repeated measures followed by Fisher’s test. p values ≤0.05 were considered to be statistically significant. Different letters indicate significant differences between groups (p < 0.05). b co-treatment with 4-PBA after 24 h significantly inhibits γ-T3- and δ-T3-induced increase of caspase-12 activity. Data were analyzed by one-way ANOVA with repeated measures followed by Fisher’s test. p values ≤0.05 were considered to be statistically significant. Different letters indicate significant differences between groups (p < 0.05)