Knockdown of wfs1, a fly homolog of Wolfram syndrome 1, in the nervous system increases susceptibility to age- and stress-induced neuronal dysfunction and degeneration in Drosophila
Fig 1
Neuronal knockdown of wfs1, a fly homolog of WFS1, causes behavioral deficits and neurodegeneration.
(A) mRNA expression levels of wfs1 were increased upon aging in the fly brains, as determined by qRT-PCR. n = 4, ***p < 0.001 by Student’s t-test. (B) A schematic diagram of the wfs1 RNAi target sites and insertion sites of MiMIC/PiggyBac for wfs1 mutant lines. (C) mRNA levels of wfs1 in heads of flies carrying the RNAi transgene targeting wfs1 were analyzed by qRT-PCR. n = 4, ***p < 0.001 by Student’s t-test. (D) Knockdown of wfs1 in neurons induced age-dependent locomotor deficits as revealed by climbing assay. Flies carrying the mcherry RNAi transgene did not induce the age-dependent locomotor deficits. Average percentages of flies that climbed to the top (white), climbed to the middle (light gray), or stayed at the bottom (dark gray) of the vials. Percentages of flies that stayed at the bottom were subjected to statistical analyses. n = 7 independent experiments, *p < 0.05, **p < 0.01 and ***p < 0.001 by Student’s t-test. (E) Neuronal knockdown of wfs1 caused age-dependent neurodegeneration in the central neuropil or optic lobes of fly brain. Representative images show the central neuropil and optic lobe in paraffin-embedded brain section with hematoxylin and eosin (HE) staining from 60-day-old flies. Scale bars: 200 μm. Percentages of vacuole areas (indicated by arrowheads in the images) in central neuropil or optic lobes from 20-, 30-, and 60-day-old flies were analyzed. n = 8–12 hemispheres, *p < 0.05 and ***p < 0.001 by Student’s t-test. (F) Neuronal knockdown of wfs1 shortened the lifespan (n = 182, wfs1 RNAi group or 358, control group). The lifespans of flies were determined by Kaplan-Meier survival analysis with log-rank test and statistical significance was indicated in the figure. Genotypes and ages of flies are described in S1 Table.