Fig. 4: Amyrel is a myokine induced by perturbation of multiprotein complexes in skeletal muscle, and upregulation of Amyrel in muscle reduces pathogenic huntingtin aggregates in the retina.

a Amyrel mRNA levels (FPKM levels) increase in skeletal muscles upon knockdown of components of multiprotein complexes (Prosb5^RNAi, VCP/TER94^RNAi, ND-75^RNAi, and Tm1^RNAi) compared to controls (GFP^RNAi, white^RNAi, and no transgene). For each condition, n = 3 biological replicates (each consisting of tissues from ~30 male flies per sample) were examined. The graph displays the mean ± SEM. P-values (*P < 0.05, **P < 0.01) were obtained from the statistical analysis of RNA-seq data. b Epifluorescence imaging of flies with CD2-GFP expression driven by Mhc-LexA-GAD indicates that this line drives transgene expression specifically in skeletal muscle and not in the retina and brain. c qRT-PCR analysis of Amyrel mRNA levels in response to LexA-responsive Amyrel transgene expression (green) induced by Mhc-LexA-GAD compared to controls (gray). The graph displays the mean ± SD and n = 3 biological replicates; **P < 0.01 (unpaired two-tailed t-test). d Analysis of aggregates of GFP-tagged huntingtin-polyQ in the retinas of flies at 30 days of age. Expression of the UAS-Htt-Q72-GFP transgene is driven in the retina with GMR-Gal4, whereas an independent binary expression system (LexA/LexAop) is utilized to induce Amyrel expression in skeletal muscle with the Mhc-LexA-GAD driver. This analysis indicates that Amyrel induction in skeletal muscle (green) reduces the accumulation of huntingtin-polyQ aggregates in the retina compared to isogenic controls (gray). The graph displays the mean ± SEM and n = 24 and n = 37 retinas, respectively; **P < 0.01 (unpaired two-tailed t-test).