Mitochondrial Dysfunction Plus High-Sugar Diet Provokes a Metabolic Crisis That Inhibits Growth

The Drosophila mutant tko(25t) exhibits a deficiency ofmitochondrial protein synthesis, leading to a global insufficiency of respiration and oxidative phosphorylation. This entrains an organismal phenotype of developmental delay and sensitivity to seizures induced bymechanical stress. We found that the mutant phenotype is exacerbated in a dose-dependent fashion by high dietary sugar levels. tko(25t) larvae were found to exhibit severe metabolic abnormalities that were further accentuated by high-sugar diet. These include elevated pyruvate and lactate, decreased ATP and NADPH. Dietary pyruvate or lactate supplementation phenocopied the effects of high sugar. Based on tissue-specific rescue, the crucial tissue in which this metabolic crisis initiates is the gut. It is accompanied by down-regulation of the apparatus of cytosolic protein synthesis and secretion at both the RNA and post-translational levels, including a novel regulation of S6 kinase at the protein level.Peer reviewe

Vastasyntyneen perushoito : Ohjausvideo vanhemmille

Opinnäytetyö tehtiin yhteistyössä Pirkanmaan sairaanhoitopiiriin (PSHP) kuuluvan Tampereen yliopistollisen sairaalan (Tays) kanssa. Opinnäytetyön tarkoituksena oli uudistaa Tays:n lapsivuodeosastoilla ja Potilashotelli Perheonnessa näytettävä ohjausvideo vastasyntyneen perushoidosta. Opinnäytetyön tavoitteena oli tuottaa uudistettua ja nykyajan vanhemmalle sopivaa ohjausmateriaalia vauvan perushoitoon ja varhaiseen vuorovaikutukseen liittyen. Ohjausvideon tavoitteena oli tukea vanhempia vauvan itsenäisessä hoidossa ja lisätä heidän luottamustaan omaan osaamiseensa. Toiminallinen opinnäytetyö koostui teoreettisesta viitekehyksestä ja yhdessä Tays:n audiovisuaalisihteerin kanssa tehdystä vauvanhoito-ohjausvideosta. Ohjausvideo koostui viidestä lyhyestä videopätkästä, joiden aiheina olivat vastasyntyneen silmien ja ihopoimujen puhdistus, navan hoito, vaipanvaihto, vastasyntyneen kylvetys ja varhainen vuorovaikutus ja ihokontakti. Teoreettisessa viitekehyksessä käsiteltiin nykyvanhempien ohjaamista, varhaista vuorovaikutusta, ihokontaktia ja vastasyntyneen perushoitoa. Jatkokehittämisehdotuksena opinnäytetyölle on uudistaa imetykseen ja äidin synnytyksestä palautumiseen liittyvä ohjausmateriaali. Opinnäytetyön tuotoksena tehty ohjausvideo on pääasiassa suunnattu suomea äidinkielenään puhuville vanhemmille. Jatkokehittämisehdotuksena on tehdä videoista myös muun kielisiä versioita.The purpose of this study was to reform the video tutorial on the care of a newborn baby, shown to new parents on the maternity ward at Tampere University Hospital and in the Patient Hotel Norlandia Care Tampere. The objective of this study was to produce updated video material on infant’s basic care that suits to modern parents. The objective of the video tutorial was to help new parents independently take care of their newborn and give more confidence for the parents to do it. This study was conducted in co-operation with Tampere University Hospital, which belongs to Pirkanmaa Hospital District. This study had a functional approach, and it consists of a theoretical framework and a video tutorial. The video tutorial was made in co-operation with an audiovisual consultant of the university hospital. The video tutorial was divided in five different subjects: how to cleanse an infant’s eyes and skin folds, how to take care of the navel, how to change the diaper, how to bathe a newborn and what is early interaction and skin-to-skin contact. The new video tutorial is shown on the maternity ward in Tampere University Hospital and in the Patient Hotel Norlandia Care Tampere. The video tutorial can also be seen on Tampere University Hospital’s Youtube-channel

dj-1β regulates oxidative stress, insulin-like signaling and development in Drosophila melanogaster

DJ-1 (or PARK-7) is a multifunctional protein implicated in numerous pathologies including cancer, sterility and Parkinson disease (PD). The popular genetic model Drosophila melanogaster has two orthologs, dj-1: α and β. Dysfunction of dj-1β strongly impairs fly mobility in an age-dependent manner. In this study, we analyze in detail the molecular mechanism underlying the dj-1β mutant phenotype. Mitochondrial hydrogen peroxide production, but not superoxide production, was increased in mutant flies. An increase in peroxide leak from mitochondria causes oxidative damage elsewhere and explains the strong reduction in mobility caused by dj-1β mutation. However, at the same time, increased levels of hydrogen peroxide activated a pro-survival program characterized by (1) an alteration in insulin-like signaling, (2) an increase in mitochondrial biogenesis and (3) an increase in the de-acetylase activity of sirtuins. The activation of this pro-survival program was associated with increased longevity under conditions of moderate oxidative stress. Additionally, the dj-1β mutation unexpectedly accelerated development, a phenotype not previously associated with this mutation. Our results reveal an important role of dj-1β in oxidative stress handling, insulin-like signaling and development in Drosophila melanogaster

dj-1β regulates oxidative stress, insulin-like signaling and development in Drosophila melanogaster

DJ-1 (or PARK-7) is a multifunctional protein implicated in numerous pathologies including cancer, sterility and Parkinson disease (PD). The popular genetic model Drosophila melanogaster has two orthologs, dj-1: α and β. Dysfunction of dj-1β strongly impairs fly mobility in an age-dependent manner. In this study, we analyze in detail the molecular mechanism underlying the dj-1β mutant phenotype. Mitochondrial hydrogen peroxide production, but not superoxide production, was increased in mutant flies. An increase in peroxide leak from mitochondria causes oxidative damage elsewhere and explains the strong reduction in mobility caused by dj-1β mutation. However, at the same time, increased levels of hydrogen peroxide activated a pro-survival program characterized by (1) an alteration in insulin-like signaling, (2) an increase in mitochondrial biogenesis and (3) an increase in the de-acetylase activity of sirtuins. The activation of this pro-survival program was associated with increased longevity under conditions of moderate oxidative stress. Additionally, the dj-1β mutation unexpectedly accelerated development, a phenotype not previously associated with this mutation. Our results reveal an important role of dj-1β in oxidative stress handling, insulin-like signaling and development in Drosophila melanogaster

Summary model of the metabolic phenotype of <i>tko</i>^<i>25t</i> in high-sugar medium.

<p>High dietary sugar and mitochondrial dysfunction stimulate glycolysis, which is nevertheless limited by the build up of pyruvate and/or lactate, produced by lactate dehydrogenase (LDH, needed to regenerate NAD+ when OXPHOS is impaired), restricting ATP production. Pyruvate and lactate accumulation restricts NADPH production, whilst NADPH consumption is increased by the need to maintain glutathione in the reduced state, despite increased mitochondrial ROS production, and by the need to reoxidize the electron acceptor (A) for glucose dehydrogenase (Gld) using the P450 system, preventing further peroxide generation. Glucose dehydrogenase converts excess glucose to gluconate, whilst any glycotoxic damage is compensated by the normal processes of protein refolding, turnover and re-synthesis, which consume ATP.</p

Effect of cycloheximide on development of <i>tko</i>^<i>25t</i> and wild-type flies.

<p>(A) Means ± SD of times to eclosion of flies of the sex and genotypes indicated, on high-sugar medium, with or without cycloheximide at the indicated concentrations. Based on pairwise <i>t</i> tests, and considering all the flies of a given sex and genotype cultured at a specific drug concentration as a single population, mean eclosion times were significantly different (<i>p</i> < 0.05) at different cycloheximide concentrations, apart from <i>tko</i>^<i>25t</i> flies of either sex at 100 μg/ml, which were not different from <i>tko</i>^<i>25t</i> flies cultured in the complete absence of the drug. (B) Pooled eclosion data from four independent experiments conducted with different concentration ranges of cycloheximide. Female developmental delay showed consistent decrease with increasing cycloheximide concentration. Males showed same trend (Panel C in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145836#pone.0145836.s005" target="_blank">S5 Fig</a>).</p

Metabolites showing substantial changes in <i>tko</i>^<i>25t</i> larvae.

<p>Relative levels of different metabolites in L3 larvae of the indicated genotypes and growth conditions, based on (A, B) findings from enzyme-linked assays or (C-F) mass spectrometry. Absolute values are shown for (B) ATP, (C) NAD+ and derivatives, (E) fructose 1,6-biphosphate (F1,6BP) and (F) gluconate, Values for (A) pyruvate, lactate and (D) amino acids are normalized to those for wild-type flies grown on ZS medium, enabling them to be plotted alongside for comparison. Relevant absolute values are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145836#pone.0145836.s008" target="_blank">S1 Table</a>. Horizontal bars denote significantly different data classes (Student’s <i>t</i> test, <i>p</i> < 0.05). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145836#pone.0145836.s014" target="_blank">S7 Table</a> for fuller statistical analysis of metabolite levels. (G) Triglyceride levels in L3 larvae of the indicated genotype and growth conditions, normalized to the value for wild-type larvae grown on zero-sugar medium. Horizontal bars denote significantly different data classes (Student’s <i>t</i> test, <i>p</i> < 0.05). Note that we did not observe increased triglyceride levels when larvae were grown on high-sugar medium.</p