Knocking down Ctr1C promotes aggregation of higher molecular weight Aβ42 forms with a trend for decreased NEP and IDE expression levels in brains of Aβ42 flies. Representative western blotting data (A) and statistical results (B). The amount of SDS-soluble Aβ42 was equivalent in Aβ42-expressing flies with Ctr1C RNAi and those without Ctr1C RNAi. However, SDS-insoluble but formic acid (FA, 70%) soluble Aβ42 forms were dramatically increased after knocking down Ctr1C. The amount of Aβ42 and actin proteins in each well were quantified by using ImageJ software, and the data showed the relative percentage of amount of Aβ42 to actin protein. Student’s t-test, **p<0.01 (in comparison with elav-Gal4>UAS-Aβ42 flies). n=3 independent experiments. The impact of Ctr1C RNAi on NEP1(C), NEP2 (D), NEP3 (E) and IDE (F) mRNA expression levels in brains of 5 and 25-day-old flies were determined by qRT-PCR. Statistical analysis showed no significant differences for the four tested enzymes between elav-Gal4>UAS-Aβ42 and elav-Gal4>UAS-Aβ42/UAS-Ctr1C RNAi flies at day 5 after eclosion. However, at day 25 after eclosion, NEP1(C), NEP3 (E) and IDE (F) mRNA expression levels were significantly decreased in brains of Ctr1C RNAi flies (elav-Gal4>UAS-Aβ42/UAS-Ctr1C RNAi). Student’s t-test, *p<0.05, **p<0.01 (in comparison with elav-Gal4>UAS-Aβ42 flies). The relative NEP1-3 and IDE expression levels against rp49 were from three independent biological replicates and plotted with SEM (error bars).