Glucocorticoids and phenotypic programming in birds

糖皮质激素和鸟类的表型编程

• 批准号: BB/E024459/2
• 负责人: Karen Spencer
• 金额: $ 32.81万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE024459%2F2
• 关键词: Glucocorticoids; phenotypic; programming; birds

When an animal's environment changes unpredictably, for example during periods of bad weather or food shortages, they suffer stress. During this time specific chemical messengers, called stress hormones, are released into the bloodstream following a series of complex interactions within a hormonal system called the hypothalamic-pituitary-adrenal axis. In the short-term these hormones can benefit the animal as they promote activities such as foraging that help it survive. If the stress continues for a period of hours or days, however, these hormones can have harmful effects. If a mother lives in a stressful environment she can pass an increased level of stress hormones to her developing offspring, and we know that if animals experience high levels of these hormones while they are growing this can have long-term effects on how they behave when they are adults. These changes in behaviour are linked to a prolonged release of stress hormones in a stressful situation, due to a disruption in regulatory systems. Some of these effects are harmful, and early stress has been linked to health problems such as hypertension or diabetes, so it is very important that we understand the physiological mechanism underlying this system. The central aim of my research is to investigate this by looking at the effects of stress hormones on animals throughout their life cycle, concentrating my attention at different biological levels, quantifying changes in gene expression, physiology, behaviour and reproductive success. One exciting aspect of this study is that I will be able to directly manipulate the stress hormone levels of individuals and track their development and behaviour throughout life. This is possible as I have chosen to work on birds; because when the mother lays her egg she transfers all the nutrients and hormones required for embryonic growth at one time, and we know that this includes stress hormones. I will mimic a stressful environment by injecting small known amounts of stress hormones into these eggs. Whilst the traditional view of developmental stress is one of harmful effects, there is an intriguing alternative perspective. Mothers could capitalise on the physiological changes that occur following exposure to stress hormones to 'engineer' their offspring in order to prepare them for the environment they will live in once they are born, maximising their chances of survival. The negative effects seen in many studies could then be a case of the environment after birth not matching the one experienced by the mother. This is a novel idea that was proposed to explain why stress hormones have such long-term effects on animals. However, very few experiments have investigated this, even though it could provide information on how stress hormones might cause later health problems. I will tackle this important topic by carrying out experiments that create post-natal environments that match or mis-match the pre-natal conditions an animal experiences. I will then follow birds as they grow and test how well they breed under favourable and unfavourable conditions. Finally I can also track the development of these birds' offspring. This will be important in helping us understand how persistent change can occur across generations without changing the genetic code, a phenomenon called epigenetic inheritance. My research will provide novel information on the importance of early life conditions in shaping helping an individual to cope with its environment. This has significant implications for human and animal health programmes and animal breeding projects. A greater understanding of epigenetic inheritance is important not just to the scientific community but may be relevant to those concerned about climate change. This is due to its potential influence on the survival of populations under uncertain environmental conditions, a circumstance that may be relevant to human and non-human animals in the years to come.

当动物的环境发生不可预测的变化时，例如在恶劣天气或食物短缺期间，它们就会承受压力。在此期间，称为应激激素的特定化学信使在称为下丘脑-垂体-肾上腺轴的激素系统内发生一系列复杂的相互作用后被释放到血液中。在短期内，这些激素可以使动物受益，因为它们可以促进觅食等有助于其生存的活动。然而，如果压力持续数小时或数天，这些激素可能会产生有害影响。如果母亲生活在充满压力的环境中，她就会将更高水平的压力荷尔蒙传递给正在发育的后代，而且我们知道，如果动物在成长过程中经历高水平的这些荷尔蒙，这可能会对它们成年后的行为产生长期影响。由于监管系统的破坏，这些行为变化与应激状态下应激激素的长期释放有关。其中一些影响是有害的，早期压力与高血压或糖尿病等健康问题有关，因此了解该系统背后的生理机制非常重要。我研究的中心目的是通过观察应激激素对动物整个生命周期的影响来研究这一问题，将我的注意力集中在不同的生物学水平上，量化基因表达、生理学、行为和繁殖成功的变化。这项研究的一个令人兴奋的方面是，我将能够直接操纵个体的压力激素水平，并跟踪他们一生的发育和行为。这是可能的，因为我选择研究鸟类；因为当母亲产卵时，她会一次性转移胚胎生长所需的所有营养物质和激素，我们知道这其中包括应激激素。我将通过向这些鸡蛋中注入少量已知量的应激激素来模拟压力环境。虽然发展压力的传统观点是一种有害影响，但还有一种有趣的替代观点。母亲可以利用暴露于应激激素后发生的生理变化来“改造”她们的后代，以便为他们出生后的生活环境做好准备，从而最大限度地提高他们的生存机会。许多研究中发现的负面影响可能是出生后的环境与母亲所经历的环境不匹配。这是一个新颖的想法，旨在解释为什么应激激素对动物有如此长期的影响。然而，很少有实验对此进行研究，尽管它可以提供有关压力荷尔蒙如何导致以后健康问题的信息。我将通过实验创造与动物所经历的产前条件相匹配或不相匹配的产后环境来解决这个重要的话题。然后，我将跟踪鸟类的生长过程，并测试它们在有利和不利条件下的繁殖情况。最后我还可以追踪这些鸟的后代的发育情况。这对于帮助我们了解如何在不改变遗传密码的情况下跨代发生持久变化（这种现象称为表观遗传）非常重要。我的研究将提供关于早期生活条件在塑造帮助个人应对环境方面的重要性的新信息。这对人类和动物健康计划以及动物育种项目具有重大影响。更好地了解表观遗传不仅对科学界很重要，而且可能与那些关注气候变化的人相关。这是因为它对不确定环境条件下种群生存的潜在影响，这种情况可能在未来几年与人类和非人类动物有关。

项目成果

Group housing during adolescence has long-term effects on the adult stress response in female, but not male, zebra finches (Taeniopygia guttata).

青春期的群体饲养对雌性斑胸草雀（Taeniopygia guttata）的成年应激反应有长期影响，但对雄性斑胸草雀没有影响。

• DOI: 10.1016/j.ygcen.2017.07.008
• 发表时间: 2018-01-15
• 期刊: General and comparative endocrinology
• 影响因子: 2.7
• 作者: Emmerson MG;Spencer KA
• 通讯作者: Spencer KA

Peri-pubertal exposure to testicular hormones organizes response to novel environments and social behaviour in adult male rats.

• DOI: 10.1016/j.yhbeh.2015.07.003
• 发表时间: 2015-07
• 期刊: Hormones and behavior
• 影响因子: 3.5
• 作者: Brown GR;Kulbarsh KD;Spencer KA;Duval C
• 通讯作者: Duval C

The mechanisms of condition-dependent variation in melanin-based plumage color.

基于黑色素的羽毛颜色的条件依赖性变化机制。

• 发表时间: 2014
• 作者: D'Alba L

Long-term effects of adolescent stress on neophobic behaviors in zebra finches are modulated by social context when in adulthood.

• DOI: 10.1016/j.yhbeh.2017.02.004
• 发表时间: 2017-04
• 期刊: Hormones and behavior
• 影响因子: 3.5
• 作者: Emmerson MG;Spencer KA
• 通讯作者: Spencer KA

Early-Life Stress Triggers Juvenile Zebra Finches to Switch Social Learning Strategies.

• DOI: 10.1016/j.cub.2015.06.071
• 发表时间: 2015-08-17
• 期刊: Current biology : CB
• 作者: Farine DR;Spencer KA;Boogert NJ
• 通讯作者: Boogert NJ