Project description:This SuperSeries is composed of the following subset Series: GSE24992: Drosophila brain microRNA expression with age: miRNA profiling GSE25007: Drosophila brain gene expression with age: mRNA profiling GSE25008: Drosophila brain gene expression between wildtype and miR-34 null flies Refer to individual Series. Aging is the most prominent risk factor for human neurodegenerative disease, but underlying mechanisms that connect two processes are less well characterized. With age, the brain undergoes functional decline and perhaps degeneration. Such decline may not just contribute to normal aging, but also enhance susceptibility to and progression of age-related neurodegenerative diseases. Therefore, defining intrinsic factors and pathways that underline the normal integrity of the adult nervous system may lead to insights that potentially link aging and neurodegeneration. Here, we report a highly conserved microRNA (miRNA), miR-34, as a modulator of aging and neurodegeneration. Using Drosophila, we show that fly miR-34 expression is brain-enriched and strikingly upregulated with age. Functional studies reveal that, whereas animals without miR-34 are normal as young adults, upon aging, they gradually show late-onset deficits characteristic of accelerated brain aging; these include a transcriptional signature of aged animals, coupled with rapid functional decline, loss of brain integrity, followed by a catastrophic decline in adult viability. Moreover, upregulation of miR-34 protects against neurodegeneration induced by pathogenic human polyglutamine (polyQ) disease protein. We next reveal a dramatic effect of miR-34 to silence the Eip74EF gene of steroid hormone pathways in the adult, which is crucial to maintain the normal aging. Collectively, these data define a miR-34-mediated mechanism that specifically affects long-term integrity of the adult nervous system. miR-34 function in Drosophila may thus present a link that functionally connects aging and neurodegeneration. Our studies implicate essential roles of miRNA- dependent pathways in maintenance of the adult brain, disease pathogenesis and healthy aging.
Project description:<p>Viral studies of Drosophila melanogaster typically involve virus injection with a small needle, causing post-injury a wounding/wound healing response, in addition to the effects of viral infection. However, the metabolic response to the needle injury is understudied, and many viral investigations neglect potential effects of this response. Furthermore, the wMel strain of the endosymbiont bacterium Wolbachia pipientis provides anti-viral protection in Drosophila. Here we used NMR-based metabolomics to characterise the acute wounding response in Drosophila and the relationship between wound healing and the Wolbachia strain wMel. The most notable response to wounding was found on the initial day of injury and lessened with time in both uninfected and Wolbachia infected flies. Metabolic changes in injured flies revealed evidence of inflammation, Warburg-like metabolism and the melanisation immune response as a response to wounding. In addition, at five days post injury Wolbachia infected injured flies were metabolically more similar to the uninjured flies than uninfected injured flies were at the same time point, indicating a positive interaction between Wolbachia infection and wound healing. This study is the first metabolomic characterisation of the wound response in Drosophila and its findings are crucial to the metabolic interpretation of viral experiments in Drosophila in both past and future studies.</p>
Project description:we performed proteome sequencing in Drosophila at day 7 (young) and day 42 (old) under dietary restriction (DR)and ad libitum (AL) conditions.
Project description:The innate immune response of insects relies on several humoral and cellular mechanisms that require the activation of circulating proteases in the hemolymph to be functional. Here, we analyzed the gelatinase and caseinase activities of Drosophila larval hemolymph under normal and pathogenic conditions (bacterial lipopolysaccharides or endoparasitoid Leptopilina boulardi) using in gel zymography. Gelatinase activity was more intense than caseinase activity and qualitative and quantitative variations were observed between D. melanogaster strains and Drosophila species. Mass spectrometry identified a large number of serine proteases in gel bands equivalent to the major gelatinase and caseinase bands and of these, the most abundant and redundant were Tequila and members of the Jonah and Trypsin protease families. However, hemolymph from Tequila null mutant larvae showed no obvious changes in zymographic bands. Nor did we observe any significant changes in hemolymph gelatinases activity 24 h after injection of bacterial lipopolysaccharides or after oviposition by endoparasitoid wasps. These data confirmed that many serine proteases are present in Drosophila larval hemolymph but those with gelatinase and caseinase activity may not change drastically during the immune response.