Alcohol Disinhibition of Behaviors in C. elegans

Alcohol has a wide variety of effects on physiology and behavior. One of the most well-recognized behavioral effects is disinhibition, where behaviors that are normally suppressed are displayed following intoxication. A large body of evidence has shown that alcohol-induced disinhibition in humans affects attention, verbal, sexual, and locomotor behaviors. Similar behavioral disinhibition is also seen in many animal models of ethanol response, from invertebrates to mammals and primates. Here we describe several examples of disinhibition in the nematode C. elegans. The nematode displays distinct behavioral states associated with locomotion (crawling on land and swimming in water) that are mediated by dopamine. On land, animals crawl and feed freely, but these behaviors are inhibited in water. We found that additional behaviors, including a variety of escape responses are also inhibited in water. Whereas alcohol non-specifically impaired locomotion, feeding, and escape responses in worms on land, alcohol specifically disinhibited these behaviors in worms immersed in water. Loss of dopamine signaling relieved disinhibition of feeding behavior, while loss of the D1-like dopamine receptor DOP-4 impaired the ethanol-induced disinhibition of crawling. The powerful genetics and simple nervous system of C. elegans may help uncover conserved molecular mechanisms that underlie alcohol-induced disinhibition of behaviors in higher animals.Funding was provided by National Institutes of Health grants from NIAAA (R01AA020992) and NINDS (R01NS075541), Waggoner Center for Alcohol and Addiction Research (http://www.utexas.edu/research/wcaar/)to JTP as well as a Bruce Jones Fellowship to ST. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Waggoner Center for Alcohol and Addiction ResearchCellular and Molecular BiologyNeuroscienceEmail: [email protected]

Ethanol Exposure during Immersion in Liquid Results in Disinhibition of Crawl Behaviors.

<p>Foraging (A), spontaneous reversals (B), touch response (C), and light response (D), as well as crawling kinematics (E,F) were disinhibited by EtOH. To ensure that such disinhibition was not the result of a decline in cellular function, worms treated with sodium azide were also assessed. No disinhibition was observed in these animals. EtOH treatment resulted in a reduction of bending frequency and a loss of C-shaped body posture. Animals treated with sodium azide experienced a similar decline in bending frequency, but no reduction in C-shape body posture. Statistical analyses comparing EtOH-, azide-, and untreated worms were performed using one-way ANOVA and Tukey's HSD post-hoc test or Kruskal-Wallis and Steel-Dwass-Critchlow-Fligner post-hoc test. Asterisks indicate significance in relation to untreated controls with P<0.001, n≥4 assays, ≥10 worms per assay for all experiments A–C, n≥15 for D–F. Error bars represent standard error of the mean.</p

Loss of D1-like Dopamine Receptor DOP-4 Reduces Disinhibition of Crawl.

<p>Loss of the D1-like receptor DOP-1 resulted in a slightly lower bending frequency versus WT with EtOH treatment (A). EtOH treatment also caused uncoordination, with significantly fewer bends propagated down the animal. This phenotype was exacerbated in <i>dop-4</i> mutant animals (B). Of body bends propagated down the animal, approximately half were C-shaped in most intoxicated animals, indicating disinhibition of crawl. Only animals lacking <i>dop-4</i> demonstrated resistance to this effect. Statistical analyses comparing EtOH-treated mutants to EtOH-treated WT controls were performed using one-way ANOVA and Tukey's HSD post-hoc test or Kruskal-Wallis and Steel-Dwass-Critchlow-Fligner post-hoc test. Asterisks indicate significance in relation to WT controls (EtOH-treated or untreated, accordingly) with P<0.001, n≥10 worms for all experiments. Letters indicate distinct groupings based on post-hoc statistical comparison among strains. Error bars represent standard error of the mean.</p

Crawl Behaviors Are Inhibited in Water.

<p>Immersion in liquid results in inhibition of many behaviors in wild-type <i>C. elegans</i>. Notably, the feeding behavior foraging (A), spontaneous reversals (B), touch response (C), and light response (D) are all inhibited. To assess disinhibition of crawl during immersion in water, headbend frequency (E) and percent body bends with C-shape (F) were assessed. In liquid, worms exhibited only a fast, C-shaped swim. Statistical analyses comparing behaviors on land vs. water were performed using planned unpaired two-tailed t-test. Asterisks indicate P<0.001, n≥4 assays, ≥10 worms per assay for all experiments A–C, n≥15 for D–F. Error bars represent standard error of the mean.</p

Select EZH2 inhibitors enhance viral mimicry effects of DNMT inhibition through a mechanism involving NFAT:AP-1 signaling

DNA methyltransferase inhibitor (DNMTi) efficacy in solid tumors is limited. Colon cancer cells exposed to DNMTi accumulate lysine-27 trimethylation on histone H3 (H3K27me3). We propose this Enhancer of Zeste Homolog 2 (EZH2)-dependent repressive modification limits DNMTi efficacy. Here, we show that low-dose DNMTi treatment sensitizes colon cancer cells to select EZH2 inhibitors (EZH2is). Integrative epigenomic analysis reveals that DNMTi-induced H3K27me3 accumulates at genomic regions poised with EZH2. Notably, combined EZH2i and DNMTi alters the epigenomic landscape to transcriptionally up-regulate the calcium-induced nuclear factor of activated T cells (NFAT):activating protein 1 (AP-1) signaling pathway. Blocking this pathway limits transcriptional activating effects of these drugs, including transposable element and innate immune response gene expression involved in viral defense. Analysis of primary human colon cancer specimens reveals positive correlations between DNMTi-, innate immune response-, and calcium signaling-associated transcription profiles. Collectively, we show that compensatory EZH2 activity limits DNMTi efficacy in colon cancer and link NFAT:AP-1 signaling to epigenetic therapy-induced viral mimicry

Microgravity effects on nonequilibrium melt processing of neodymium titanate: thermophysical properties, atomic structure, glass formation and crystallization

Abstract The relationships between materials processing and structure can vary between terrestrial and reduced gravity environments. As one case study, we compare the nonequilibrium melt processing of a rare-earth titanate, nominally 83TiO2-17Nd2O3, and the structure of its glassy and crystalline products. Density and thermal expansion for the liquid, supercooled liquid, and glass are measured over 300–1850 °C using the Electrostatic Levitation Furnace (ELF) in microgravity, and two replicate density measurements were reproducible to within 0.4%. Cooling rates in ELF are 40–110 °C s−1 lower than those in a terrestrial aerodynamic levitator due to the absence of forced convection. X-ray/neutron total scattering and Raman spectroscopy indicate that glasses processed on Earth and in microgravity exhibit similar atomic structures, with only subtle differences that are consistent with compositional variations of ~2 mol. % Nd2O3. The glass atomic network contains a mixture of corner- and edge-sharing Ti-O polyhedra, and the fraction of edge-sharing arrangements decreases with increasing Nd2O3 content. X-ray tomography and electron microscopy of crystalline products reveal substantial differences in microstructure, grain size, and crystalline phases, which arise from differences in the melt processes