Cathepsin Inhibition-Induced Lysosomal Dysfunction Enhances Pancreatic Beta-Cell Apoptosis in High Glucose
Figure 6
Inhibition of cathepsins B and L causes severe lysosomal dysfunction.
(A) Lysotracker staining was performed in INS-1 cells cultured in 30 mM glucose for 24 or 48 hr, treated daily with E64d (E, 20 μg/mL), cathepsin B inhibitor (CBi, 20 μM), and cathepsin L inhibitor (CLi, 20 μM). Nuclei were stained with Hoechst 33342 dye. (B) INS-1 cells were transfected mRFP-GFP-LC3 construct and then treated with cathepsin B and L inhibitors in 30 mM glucose for 48 hr. 30 mM glucose medium alone increased red and yellow puncta (autolysosome, left panel), whereas treatment with cathepsin inhibitors increased only yellow puncta (autophagosome, middle and right panel). The scale bar represents 5 μm.