Research Paper Volume 13, Issue 8 pp 10866—10890

Pharmacologic activation of autophagy without direct mTOR inhibition as a therapeutic strategy for treating dry macular degeneration


Figure 4. Autophagy inducer FLBZ reduces accumulation of lipofuscin-like material. (A) Lipofuscin-like UAM accumulates in RPE after repeated feedings of photo-oxidized outer segments (oxOS). UAM granules (green). DAPI (blue). Phalloidin stain of F-actin outlining cell borders (pink). Scale bar: 10 μm. (B) Effects of FLBZ or Torin on UAM accumulation (left) and elimination (right). FLBZ or Torin is fed together with oxOS daily for 20 days in a month (left, n=5) or fed daily for 20 days in a month after completion of oxOS feedings to stimulate UAM accumulation (right, n=7). Unlike Torin, FLBZ both reduces UAM accumulation and increases UAM elimination. DMSO as vehicle control. UAM normalized to DMSO condition. (C) LC3 colocalization to UAM granules in the human RPE cell line, ARPE-19, treated with FLBZ. UAM (red). LC3 (green). DAPI (blue). Arrows indicate LC3 puncta surrounding a lipofuscin granule. Scale bar: 2 μm. (D) Effects of FLBZ on UAM granule size. Compared to vehicle (DMSO), FLBZ decreases UAM granule size both during oxOS feedings (left) and after UAM buildup has already occurred (right). n=40. ns p > 0.05, *p < 0.05, **p < 0.01, ***p < 0.001.