Roles of hypothermia in response to environmental hypoxia: Behavioural and thermal modulation of the genetic and proteomic responses to low oxygen

我们将首次研究低氧(低氧)诱导的基因表达与行为低温的相互依赖关系。这项工作最好在体温较低的动物身上进行，因为它们的体温会随着环境的变化而变化。我们将使用一种入侵害虫--Pacifastacus leniusculus，它正在取代濒临灭绝的本土物种。当面临较低的环境氧气时，这些物种会寻找更凉爽的环境，从而降低代谢率和氧气需求。对低氧的正常生理反应包括基因表达和蛋白质谱的潜在变化。这种基因转录受缺氧诱导因子(HIF)的调节，如果有足够的氧气，HIF通常会被降解。我们将研究令人兴奋的可能性，即行为诱导的低温可以通过减少组织需氧量来调节基因表达。最近和诱人的证据表明，能量代谢的代谢物可能调节基因转录和行为的协调反应，甚至这种行为是基因表达变化的结果。我们将与戈尔博士/加斯曼教授(苏黎世)合作。其目的是展示行为如何调节基因表达，或者是如何与基因表达相协调。我们将描述低氧条件下动物尾部肌肉的低氧基因反应以及由此导致的蛋白质谱的变化，并确定体温降低是否会消除这种基因和蛋白质反应。我们将通过药理学的方法来探索行为和低氧诱导基因转录之间的联系。使用抑制HIF降解的抑制剂，即使在常氧细胞中，我们也将在以下方面建立依赖反应：(A)基因转录，(B)蛋白质谱和(C)行为。后一点几乎是独一无二的，因为它使用行为作为基因表达的分析。我们将使用外源性HIF降解抑制剂(对动物来说不是天然的)，以及抑制HIF降解并可能刺激行为的能量代谢产物。因此，促进求寒行为和诱导低氧反应基因的代谢物的作用将把这两种反应联系在一起。外源化合物的影响，刺激行为的结果是缺氧反应基因表达的变化，也就是说，行为是通过基因表达的变化而促进的。这项研究将揭示能量代谢是否直接依赖于基因对低氧的反应，以及这是否受到行为的调节。潜在的影响范围从环境到生物医学。HIF系统是肿瘤治疗的靶点，有证据表明温度和代谢产物对能量代谢的作用是直接相关的。如果我们证明对缺氧的行为反应和分子反应是分开的(行为延迟了分子反应)，那么对于能够获得更凉爽栖息地的动物来说，这将具有重大的生态意义。如果我们证明行为和分子反应是由代谢信号联系在一起的，或者行为是由分子事件引起的，那么这将为生态、环境和生物医学研究开辟新的领域。在生理和行为反应中发现新的反馈(或前馈)系统，对于理解物种的成功、蛋白质周转的时间成本以及细胞的行为，无论是肿瘤细胞还是来自环境压力的动物都有意义。低氧是限制水生物种分布和成功的重要环境因素(如河流和湖泊的富营养化)。任何物种存活的可能性在很大程度上取决于缺氧反应的性质和程度。物种间这种反应的差异可以导致动物区系组合的变化，这可能与我们研究中的小菜蛾有关，因为它取代了本地物种，部分原因是由于它具有更强的抗逆性和存活率。

We will conduct the first investigation of the interdependence of hypoxia (low oxygen) induced gene expression and behavioural hypothermia. The work is best carried out in ectothermic animals, whose body temperature changes with that of the environment. We will use an invasive pest crayfish, Pacifastacus leniusculus, which is displacing the endangered native species. When faced with lowered environmental oxygen such species seek out a cooler environment, thereby lowering metabolic rate and oxygen demand. Normal physiological responses to hypoxia include underlying changes in gene expression and protein profiles. This gene transcription is regulated by a hypoxia inducible factor (HIF) which is normally degraded if sufficient oxygen is present. We will examine the exciting possibility that behavioural induced hypothermia can modulate gene expression by reducing tissue oxygen demand. Recent and tantalising evidence indicates that metabolites of energy metabolism may regulate a coordinated response in gene transcription and behaviour, or even that behaviour is a result of changes in gene expression. We will collaborate with Dr Gorr/Prof Gassmann (Zurich). The aim is to show how behaviour may modulate gene expression or, alternatively, is coordinated with gene expression. We will characterise the hypoxic gene response and the resulting changes in the protein profile of the tail muscle of animals in low oxygen, compared to normal oxygen, and determine if lowered body temperature obviates this gene and protein response. We will probe the linkage between behaviour and hypoxia induce gene transcription by a pharmacological approach. Using inhibitors that block HIF degradation, even in normoxic cells, we will establish dependent responses in; (a) gene transcription, (b) protein profiles and (c) behaviour. This latter point is near unique since it uses behaviour as assay of gene expression. We will use exogenous inhibitors (not natural to the animal) of HIF degradation, as well as metabolites of energy metabolism which inhibit HIF degradation and putatively stimulate the behaviour. Thus, effects of metabolites that promote cold-seeking behaviour and induce hypoxia responsive genes will link the two responses. Effects of exogenous compounds, that stimulate behaviour will do so as a consequence of changes in the expression of hypoxia responsive genes, that is behaviour is promoted by changed gene expression. The study will reveal if energy metabolism feeds back directly on genes in response to hypoxia and if this is modulated by behaviour. The potential implications range from environmental to biomedical. The HIF system is a target for tumour treatment and evidence as to the role of temperature and metabolites of energy metabolism is directly relevant. Should we prove that the behavioural and molecular responses to hypoxia are separate (behaviour delays the molecular response), there will be large ecological significance for animals with access to cooler habitats. Should we prove that behaviour and molecular responses are linked by metabolic signals or that behaviour is caused by molecular events then this will open new areas of ecological, environmental and biomedical investigation. Discovering new feedback (or feed-forward) systems in physiological and behavioural responses has implications for understanding species success, temporal costs in protein turnover, and the behaviour of cells, be they tumour cells or from environmentally stressed animals. Hypoxia is an important environmental factor limiting the distribution and success of aquatic species (e.g. eutrophication of rivers and lakes). The likelihood for any species survival depends significantly on the nature and extent of the hypoxic response. Variation in this response between species can lead to changes in the faunal mix, which may be of relevance for P. leniusculus in our study since it is displacing the native species, in part, due a greater hardiness and survivorship.