Atg4b-Dependent Autophagic Flux Alleviates Huntington’s Disease Progression
Figure 8
Atg4b dependent-autophagy flux attenuates HD progression.
A) Representative images for tTa/Exon1-72Q and Atg4b/Exon1-72Q cortical neurons treated or not with AZD8055 at 8 days post lentiviral infection (dpi). Note the enhanced mHtt accumulation (green) in both Atg4b/Exon1-72Q +/− AZD8055 neurons. B) Quantitative analysis of mHtt intensity per area. Note that AZD8055 reduced mHtt accumulation in tTa/Exon1-72Q neurons but had no effect in Atg4b/Exon1-72Q neurons. C) Representative images of neurons in CStS transfected with gene gun expressing Atg4b or GFP at DIV7 and DIV28. Note how Atg4b accelerates the appearance of mHtt accumulation in neurons of R6/2 slices at DIV7, but it is not inducing toxicity in WT slices. D) Left: quantitative distribution of mHtt accumulation in R6/2 Atg4b and R6/2 GFP expressing neurons at DIV7 and 28. Note how the percentage of mHtt accumulation is almost similar between R6/2 Atg4b neurons at DIV7 and R6/2 GFP neurons at DIV28. Middle: distribution of positive neurons in R6/2 GFP and R6/2 Atg4b slices at DIV 7, 10 and 28. No R6/2 Atg4b neurons were detected at DIV10 and 28. On the other hand WT Atg4b neurons were detected at DIV28, suggesting mHtt-dependent toxicity in the R6/2 Atg4b neurons. Right: AZD8055 is not rescuing the loss of Atg4b neurons in R6/2 slices at DIV10. A) N = 50 images from 3 independent preparations; (C) N = 10 images from 5 independent slices; median values ± SEM; Student’s t test: *p<0.05, **p<0.01 Bars: 10 µm.
