Mitochondrial dysfunctions belong amongst the most common metabolic diseases but the signalling networks that lead to the manifestation of a disease phenotype are often not well understood. We identified the subunits of respiratory complex I, III and IV as mediators of major signalling changes during Drosophila wing disc development. Their downregulation in larval wing disc leads to robust stimulation of TOR activity, which in turn orchestrates a complex downstream signalling network. Specifically, after downregulation of the complex I subunit ND-49 (mammalian NDUFS2), TOR activates JNK to induce cell death and ROS production essential for the stimulation of compensatory apoptosis-induced proliferation within the tissue. Additionally, TOR upregulates Notch and JAK/STAT signalling and it directs glycolytic switch of the target tissue. Our results highlight the central role of TOR signalling in mediating the complex response to mitochondrial respiratory dysfunction and they provide a rationale why the disease symptoms associated with respiratory dysfunctions are often alleviated by mTOR inhibitors.

• MeSH
• down regulace MeSH
• Drosophila MeSH
• Janus kinasy metabolismus   MeSH
• křídla zvířecí růst a vývoj   metabolismus   MeSH
• proteiny Drosophily genetika   metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• receptory Notch metabolismus   MeSH
• respirační komplex I genetika   metabolismus   MeSH
• signální transdukce * MeSH
• transkripční faktory STAT metabolismus   MeSH
• tyrosinkinasové receptory metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: In fly brains, the Drosophila Adar (adenosine deaminase acting on RNA) enzyme edits hundreds of transcripts to generate edited isoforms of encoded proteins. Nearly all editing events are absent or less efficient in larvae but increase at metamorphosis; the larger number and higher levels of editing suggest editing is most required when the brain is most complex. This idea is consistent with the fact that Adar mutations affect the adult brain most dramatically. However, it is unknown whether Drosophila Adar RNA editing events mediate some coherent physiological effect. To address this question, we performed a genetic screen for suppressors of Adar mutant defects. Adar5G1 null mutant flies are partially viable, severely locomotion defective, aberrantly accumulate axonal neurotransmitter pre-synaptic vesicles and associated proteins, and develop an age-dependent vacuolar brain neurodegeneration. RESULTS: A genetic screen revealed suppression of all Adar5G1 mutant phenotypes tested by reduced dosage of the Tor gene, which encodes a pro-growth kinase that increases translation and reduces autophagy in well-fed conditions. Suppression of Adar5G1 phenotypes by reduced Tor is due to increased autophagy; overexpression of Atg5, which increases canonical autophagy initiation, reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar mutant phenotypes tested. Endosomal microautophagy (eMI) is another Tor-inhibited autophagy pathway involved in synaptic homeostasis in Drosophila. Increased expression of the key eMI protein Hsc70-4 also reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar5G1 mutant phenotypes tested. CONCLUSIONS: These findings link Drosophila Adar mutant synaptic and neurotransmission defects to more general cellular defects in autophagy; presumably, edited isoforms of CNS proteins are required for optimum synaptic response capabilities in the brain during the behaviorally complex adult life stage.

• MeSH
• adenosindeaminasa genetika   metabolismus   MeSH
• autofagie * MeSH
• Drosophila melanogaster genetika   růst a vývoj   fyziologie   MeSH
• larva genetika   růst a vývoj   fyziologie   MeSH
• mutace MeSH
• nervový přenos genetika   MeSH
• proteiny Drosophily genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: In models extensively used in studies of aging and extended lifespan, such as C. elegans and Drosophila, adult senescence is regulated by gene networks that are likely to be similar to ones that underlie lifespan extension during dormancy. These include the evolutionarily conserved insulin/IGF, TOR and germ line-signaling pathways. Dormancy, also known as dauer stage in the larval worm or adult diapause in the fly, is triggered by adverse environmental conditions, and results in drastically extended lifespan with negligible senescence. It is furthermore characterized by increased stress resistance and somatic maintenance, developmental arrest and reallocated energy resources. In the fly Drosophila melanogaster adult reproductive diapause is additionally manifested in arrested ovary development, improved immune defense and altered metabolism. However, the molecular mechanisms behind this adaptive lifespan extension are not well understood. RESULTS: A genome wide analysis of transcript changes in diapausing D. melanogaster revealed a differential regulation of more than 4600 genes. Gene ontology (GO) and KEGG pathway analysis reveal that many of these genes are part of signaling pathways that regulate metabolism, stress responses, detoxification, immunity, protein synthesis and processes during aging. More specifically, gene readouts and detailed mapping of the pathways indicate downregulation of insulin-IGF (IIS), target of rapamycin (TOR) and MAP kinase signaling, whereas Toll-dependent immune signaling, Jun-N-terminal kinase (JNK) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways are upregulated during diapause. Furthermore, we detected transcriptional regulation of a large number of genes specifically associated with aging and longevity. CONCLUSIONS: We find that many affected genes and signal pathways are shared between dormancy, aging and lifespan extension, including IIS, TOR, JAK/STAT and JNK. A substantial fraction of the genes affected by diapause have also been found to alter their expression in response to starvation and cold exposure in D. melanogaster, and the pathways overlap those reported in GO analysis of other invertebrates in dormancy or even hibernating mammals. Our study, thus, shows that D. melanogaster is a genetically tractable model for dormancy in other organisms and effects of dormancy on aging and lifespan.

• MeSH
• dlouhověkost genetika   MeSH
• Drosophila melanogaster genetika   fyziologie   MeSH
• genom hmyzu MeSH
• genová ontologie MeSH
• inzulin genetika   MeSH
• regulace genové exprese * MeSH
• rozmnožování genetika   MeSH
• signální transdukce MeSH
• stárnutí genetika   fyziologie   MeSH
• transkriptom genetika   MeSH
• zárodečné buňky metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Ageing constitutes the most important risk factor for all major chronic ailments, including malignant, cardiovascular and neurodegenerative diseases. However, behavioural and pharmacological interventions with feasible potential to promote health upon ageing remain rare. Here we report the identification of the flavonoid 4,4'-dimethoxychalcone (DMC) as a natural compound with anti-ageing properties. External DMC administration extends the lifespan of yeast, worms and flies, decelerates senescence of human cell cultures, and protects mice from prolonged myocardial ischaemia. Concomitantly, DMC induces autophagy, which is essential for its cytoprotective effects from yeast to mice. This pro-autophagic response induces a conserved systemic change in metabolism, operates independently of TORC1 signalling and depends on specific GATA transcription factors. Notably, we identify DMC in the plant Angelica keiskei koidzumi, to which longevity- and health-promoting effects are ascribed in Asian traditional medicine. In summary, we have identified and mechanistically characterised the conserved longevity-promoting effects of a natural anti-ageing drug.

• MeSH
• Angelica chemie   MeSH
• autofagie účinky léků   MeSH
• buněčná smrt účinky léků   MeSH
• buněčné linie účinky léků   MeSH
• Caenorhabditis elegans účinky léků   MeSH
• dlouhověkost účinky léků   fyziologie   MeSH
• Drosophila melanogaster účinky léků   MeSH
• flavonoidy aplikace a dávkování   farmakologie   MeSH
• ischemická choroba srdeční farmakoterapie   MeSH
• lidé MeSH
• mechanistické cílové místo rapamycinového komplexu 1 metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• proteiny přenášející kationty genetika   MeSH
• regulace genové exprese účinky léků   MeSH
• rostlinné extrakty farmakologie   MeSH
• Saccharomyces cerevisiae - proteiny genetika   MeSH
• Saccharomyces cerevisiae účinky léků   metabolismus   MeSH
• signální transdukce MeSH
• sirolimus farmakologie   MeSH
• stárnutí účinky léků   fyziologie   MeSH
• tradiční orientální medicína MeSH
• transkripční faktory GATA účinky léků   MeSH
• transkripční faktory účinky léků   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH