Reproduction Immunity Trade-Off in a Mollusk: Hemocyte Energy Metabolism Underlies Cellular and Molecular Immune Responses
Reproduction Immunity Trade-Off in a Mollusk: Hemocyte Energy Metabolism Underlies Cellular and Molecular Immune Responses
复制标题
DOI：
10.3389/fphys.2019.00077
复制
发表时间：
2019-02-11
影响因子：
4
通讯作者：
Rivera-Ingraham, Georgina A.
中科院分区：
文献类型：
--
作者：
Brokordt, Katherina;Defranchi, Yohana;Rivera-Ingraham, Georgina A.
免疫反应和繁殖都是需要能量的过程，特别是在扇贝等传播产卵者中。因此，我们的目的是探讨潜在的生殖免疫权衡在Argopecten purpurpuratus，一个物种具有巨大的经济意义，为智利和秘鲁。血细胞，在软体动物中的关键免疫细胞，是本研究的中心，在那里我们第一次解决了生殖阶段，血细胞代谢能量和它们的能力，以支持免疫反应在细胞和分子水平之间的关系。通过呼吸速率、线粒体膜电位和柠檬酸合酶（CS）活性评价血细胞代谢能力。考虑了细胞免疫参数，如循环和组织浸润血细胞的数量及其活性氧（ROS）产生能力。通过两种模式识别受体（ApCLec和ApTLR）和两种抗微生物效应物（铁蛋白和大防御素）的转录水平来检查分子免疫应答。它们的表达在来自未成熟的、成熟的和产卵的扇贝的血细胞中在基础和以下挑战之一下测量：（i）在体外，其中用β葡聚糖酵母聚糖挑战血细胞，以确定在标准化条件下的免疫潜力;或（ii）在体内挑战，使用来自注射有病原性细菌灿烂弧菌的扇贝的血细胞。结果表明，产卵后减少免疫系统的结构组成部分（血细胞数量/质量）和执行免疫功能的潜在能力（减少ATP生产机器和能源储备耗尽）。在体外和体内的挑战表明，来自未成熟的扇贝的血细胞，在大多数情况下，具有最好的代谢潜力（增加CS活性）和免疫性能，例如，超过三倍高的ROS生产和组织浸润能力比那些从成熟和产卵扇贝后的细菌挑战。与细胞反应相一致，未成熟个体的血细胞在细菌挑战后诱导了最高水平的免疫受体和抗菌效应物，而产卵扇贝的值最低。总体而言，结果表明，在生殖资源分配和免疫反应之间的权衡在A。purpuratus，具有潜在的细胞和分子免疫应答的血细胞能量代谢能力。进一步的研究将是必要的，以探索监管机制，如信号多效性，这可能是潜在的这种权衡。
Immune responses, as well as reproduction, are energy-hungry processes, particularly in broadcast spawners such as scallops. Thus, we aimed to explore the potential reproduction-immunity trade-off in Argopecten purpuratus, a species with great economic importance for Chile and Peru. Hemocytes, key immunological cells in mollusks, were the center of this study, where we addressed for the first time the relation between reproductive stage, hemocyte metabolic energetics and their capacity to support immune responses at cellular and molecular levels. Hemocyte metabolic capacity was assessed by their respiration rates, mitochondrial membrane potential and citrate synthase (CS) activity. Cellular immune parameters such as the number of circulating and tissue-infiltrating hemocytes and their reactive oxygen species (ROS) production capacity were considered. Molecular immune responses were examined through the transcriptional levels of two pattern recognition receptors (ApCLec and ApTLR) and two anti-microbial effectors (ferritin and big defensin). Their expressions were measured in hemocytes from immature, matured and spawned scallops under basal, and one of the following challenges: (i) in vitro, where hemocytes were challenged with the beta glucan zymosan, to determine the immune potentiality under standardized conditions; or (ii) in vivo challenge, using hemocytes from scallops injected with the pathogenic bacteria Vibrio splendidus. Results indicate a post-spawning decrease in the structural components of the immune system (hemocyte number/quality) and their potential capacity of performing immune functions (with reduced ATP-producing machinery and exhaustion of energy reserves). Both in vitro and in vivo challenges demonstrate that hemocytes from immature scallops have, in most cases, the best metabolic potential (increased CS activity) and immune performances, with for example, over threefold higher ROS production and tissue-infiltration capacity than those from mature and spawned scallops after the bacterial challenge. Agreeing with cellular responses, hemocytes from immature individuals induced the highest levels of immune receptors and antimicrobial effectors after the bacterial challenge, while spawned scallops presented the lowest values. Overall, results suggest a trade-off between resource allocation in reproduction and the immune responses in A. purpuratus, with hemocyte energy metabolic capacity potentially underlying cellular and molecular immune responses. Further research would be necessary to explore regulatory mechanisms such as signaling pleiotropy which may potentially be underlying this trade-off.