Eip74EF is a dominant modifier for ALS-FTD linked mutant VCP phenotypes in Drosophila, but not miR-34

In 2012 Liu et al. reported that miR-34 is an age-related miRNA regulating age-associated events and long-term brain integrity in Drosophila. They demonstrated that modulating miR-34 and its downstream target Eip74EF showed beneficial effects on age-related diseases using a Drosophila model of SCA3trQ78. These results imply that miR-34 could be a general genetic modifier and therapeutic candidate for age-related diseases. Therefore, we examined the effect of miR-34 and Eip74EF on another age-related Drosophila disease model. Using a Drosophila model expressing mutant Drosophila VCP that causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), or multisystem proteinopathy (MSP), we demonstrated that abnormal eye phenotypes generated by Drosophila VCP R152H were rescued when expressed with Eip74EF siRNA. Contrary to our expectation, miR-34 overexpression resulted in lethality when expressed with mutant VCP. Our data indicate that the other downstream targets of miR-34 might more significantly interact with mutant VCP, causing lethality. Identifying transcriptional targets of Eip74EF might provide valuable insights into diseases caused by mutations in VCP such as ALS, FTD, and MSP.