Quercetin Affects Hsp70/IRE1α Mediated Protection from Death Induced by Endoplasmic Reticulum Stress

Figure 3

IRE1α expression is linked to Hsp70. (a) Western blot was performed with anti-IRE1α followed by peroxidase-conjugated secondary antibody to analyze this ER sensor in the lysates of untreated (0 h) or TN treated U937 cells for the hours indicated. Western blot of β-actin is shown at the bottom as a loading control. Representative blots are shown. Densitometric quantification of the bands is shown at the bottom of the relevant lines as the ratio of IRE1α in each line to the IRE1α value observed in the lysate of untreated U937 cells. (b) Western blot was performed with anti-IRE1α followed by peroxidase-conjugated secondary antibody to analyze this ER sensor in the lysates of untreated cells or Q (10 μM) or PES (10 μM) pretreated cells, thereafter treated with none or TN or TG for 24 h. Western blot of caspase 3 is shown at the bottom as a loading control. Representative blots are shown. Densitometric quantification of the bands is shown at the bottom of the relevant lines as the ratio of IRE1α in each line to the IRE1α value observed in the lysate of untreated U937 cells. (c) Western blot analysis of IRE1α by specific antibody in the lysates of U937 cells transfected with equal amounts of Hsp70 siRNA or scr-siRNA (Santa Cruz) for 72 h and exposed to none or to TN 1 μM for further 24 h. Western blot analysis of β-actin is shown at the bottom, as a loading control and also to confirm the specificity of the transfected siRNA. Representative blots are shown. Densitometric quantification of the bands is shown at the bottom of the relevant lines as the ratio of IRE1α in each line to the IRE1α value observed in the lysate of untreated U937 cells transfected with scrambled siRNA.

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