Drosophila egg-derived tyrosine phosphatase (EDTP): a novel target for improved survivorship to prolonged anoxia and cellular protein aggregates

Drosophila egg-derived tyrosine phosphatase (EDTP), a lipid phosphatase that removes 3-position phosphate at the inositol ring, has dual functions in the oogenesis and the muscle performance during adult stages. A mammalian homologous gene MTMR14, which encodes the myotubularin-related protein 14, negatively regulates autophagy. Mutation of EDTP/MTMR14, however, causes at least three deleterious consequences: (1) lethality in the early embryogenesis in Drosophila; (2) "jumpy" phenotype with apparently impaired motor functions; and (3) association with a rare genetic disorder called centronuclear myopathy. Here we show that flies carrying a heterozygous EDTP mutation had increased survivorship to prolonged anoxia; tissue-specific downregulation of EDTP in non-muscle tissues, particularly motoneurons, extended the lifespan; and tissue-specific downregulation of EDTP in motoneurons improved the survivorship to beta-amyloid peptides (Aβ42) and polyglutamine (polyQ) protein aggregates. MTMR14 expression was evident in the hippocampus and cortex in C57BL/6J and APP/PS1 mice. Compared with C57BL/6J mice, APP/PS1 mice had reduced MTMR14 in the cortex but not in the hippocampus. Hippocampal expression of MTMR14 was increased and plateaued at 9-17 months compared with 2-6 months in C57BL/6J mice. Aβ42 treatment increased the expression of MTMR14 in the primarily cultured hippocampal neurons of Sprague/Dawley rats and mouse Neuro2a neuroblasts. We demonstrated a novel approach of tissue-specific manipulation of the disease-associated gene EDTP/MTMR14 for lifespan extension and the improvement of survivorship to cellular protein aggregates.