Amphibian innate immunity and impact of environmental stress

两栖动物先天免疫和环境压力的影响

• 批准号: RGPIN-2017-04218
• 负责人: Katzenback, Barbara
• 金额: $ 2.19万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710444
• 关键词: Amphibian; innate; immunity; impact; environmental

One third of >7000 amphibian species are threatened globally. The etiology is complex, with emerging pathogens the proximal cause. Mass amphibian die-offs resulting from fungal and viral infections suggest an environment that undermines frog immune system competency to defend against infection. At the forefront of innate immunity, the first line of defense against pathogens, is the skin epithelial barrier and the surface secreted host defense peptides (HDPs). Together they act as the interface between an organism's external and internal environments. Great diversity of HDPs is found amongst amphibians and studies have documented their antimicrobial activity against a broad-spectrum of pathogens. Recent discoveries in mammals suggest HDPs are multifaceted and play an important role in immune modulation through coordination of molecular and cellular networks. Despite this, studies on amphibian HDPs have been greatly hampered due to a lack of feasible in vitro systems to study their activity. My research program aims to address this knowledge gap in order to understand the immune modulating activity of frog HDPs on frog epithelial cells, how this activity impacts resistance to pathogens, and how these host-pathogen interactions may be affected by changes in environmental temperature as a result of climate change, leading to disease susceptibility and amphibian mortality. Recently, my lab has generated and characterized a Xenopus laevis dorsal skin epithelial cell line (Xela DS2) that is susceptible to infection with a known frog pathogen (Frog virus 3, FV3), placing my laboratory in a unique (and only) position to elucidate the molecular and functional roles of frog HDPs as immune modulators. My research will use a global systems approach from transcriptomics to intracellular pathway activation to cell function and pathogen challenge to elucidate the regulation of key immune genes (cytokines, chemokines, HDPs) and identify novel gene targets. This innovative approach will integrate HDP-driven molecular events with epithelial cell function and FV3 susceptibility, focusing on how temperature shifts associated with climate change perturb these host-pathogen dynamics at the level of the skin epithelial barrier. These novel approaches will be translated to the native North American wood frog that has evolved to withstand extreme changes in temperature to illuminate conserved and divergent mechanisms of host immunity and response to environmental stress. My research will significantly advance our understanding of how complex host-pathogen-environment interactions may be impacting Canadian frog species and will explore the utility of HDP therapy as a prevention or treatment strategy to mitigate pathogen-related amphibian deaths. These studies are instrumental for the design of pathogen prevention strategies and implementation of policies for amphibian conservation in Canada.

7000种两栖动物中有三分之一在全球范围内受到威胁。病因很复杂，新出现的病原体是近端原因。真菌和病毒感染导致的两栖动物大规模死亡表明，环境破坏了青蛙防御感染的免疫系统能力。在先天免疫的最前线，抵御病原体的第一道防线是皮肤上皮屏障和表面分泌的宿主防御肽(HDPs)。它们共同充当有机体外部和内部环境之间的接口。HDP在两栖动物中发现了极大的多样性，研究证明了它们对广泛病原体的抗菌活性。最近在哺乳动物中的发现表明，HDPs是多方面的，通过分子和细胞网络的协调在免疫调节中发挥重要作用。尽管如此，由于缺乏可行的体外系统来研究其活性，两栖类HDP的研究受到了极大的阻碍。我的研究计划旨在解决这一知识差距，以了解青蛙HDP对青蛙上皮细胞的免疫调节活性，这一活动如何影响对病原体的抵抗力，以及这些宿主与病原体的相互作用可能如何受到气候变化导致的环境温度变化的影响，从而导致疾病易感性和两栖动物死亡。最近，我的实验室建立并鉴定了非洲爪哇背部皮肤上皮细胞系(Xela DS2)，该细胞系对已知的青蛙病原体(青蛙病毒3，FV3)敏感，使我的实验室处于独特的(也是唯一的)阐明青蛙HDPs作为免疫调节剂的分子和功能作用的位置。我的研究将使用从转录转录到细胞内途径激活再到细胞功能和病原体挑战的全球系统方法来阐明关键免疫基因(细胞因子、趋化因子、HDPs)的调节并确定新的基因靶点。这一创新的方法将把HDP驱动的分子事件与上皮细胞功能和FV3易感性结合起来，重点研究与气候变化相关的温度变化如何在皮肤上皮屏障水平上扰乱这些宿主-病原体的动态。这些新的方法将被翻译到北美本土林蛙，这种林蛙已经进化到能够承受极端的温度变化，以阐明宿主免疫和对环境压力的反应的保守和不同的机制。我的研究将极大地促进我们对复杂的宿主-病原体-环境相互作用如何影响加拿大青蛙物种的理解，并将探索HDP疗法作为预防或治疗策略的用途，以减少与病原体相关的两栖动物死亡。这些研究有助于加拿大制定病原体预防战略和实施两栖动物保护政策。