PDF(Pubmed)
Abstract：
Nervous necrosis virus (NNV) is one of the greatest threats to Mediterranean aquaculture, infecting more than 170 fish species and causing mortalities up to 100% in larvae and juveniles of susceptible species. Intensive aquaculture implies stressed conditions that affect the welfare of fish and their ability to fight against infections. In fact, a higher susceptibility to NNV has been related to poor welfare conditions. In order to analyze the physiological link between stressed conditions and increased susceptibility to NNV, as well as its possible role in the pathogenesis of this disease, we reared shi drum (Umbrina cirrosa) juveniles (30.7 ± 3.10 g body weight), which are expected to be asymptomatic upon NNV infection, at three stocking densities (2, 15, and 30 kg/m3) for 27 days and subsequently challenged them with NNV. We firstly characterized the stressed conditions of the specimens before and after infection and recorded the mortalities, demonstrating that stressed specimens reared at 30 kg/m3 suffered mortalities. However, the viral loads in different tissues were similar in all experimental groups, allowing horizontal and vertical transmission of the virus from asymptomatic specimens. All of these data suggest that shi drum tolerates wide ranges of culture densities, although high densities might be a setback for controlling NNV outbreaks in this species. In an attempt to understand the molecular pathways orchestrating this susceptibility change in stressed conditions, we performed a transcriptomic analysis of four tissues under mock- and NNV-infected conditions. In addition to the modification of the exceptive pathways such as cell adhesion, leukocyte migration, cytokine interaction, cell proliferation and survival, and autophagy, we also observed a heavy alteration of the neuroactive ligand-receptor pathway in three of the four tissues analyzed. Our data also point to some of the receptors of this pathway as potential candidates for future pharmacological treatment to avoid the exacerbated immune response that could trigger fish mortalities upon NNV infection.
摘要：
神经坏死病毒（NNV）是地中海水产养殖的最大威胁之一，感染170多种鱼类，并在易感物种的幼虫和幼体中造成高达100％的死亡率。集约化水产养殖意味着压力大的条件会影响鱼类的福利及其抵抗感染的能力。事实上,对NNV的敏感性较高与福利条件差有关。为了分析应激条件与NNV易感性增加之间的生理联系，以及它在这种疾病的发病机理中的可能作用，我们饲养了石鼓（Umbrinacirrosa）少年（30.7±3.10克体重），预计在NNV感染后无症状，在三个放养密度（2、15和30kg/m3）下持续27天，随后用NNV挑战它们。我们首先对感染前后标本的应激状态进行了表征，并记录了死亡率，证明以30kg/m3饲养的受压标本死亡率。然而,所有实验组不同组织中的病毒载量相似，允许病毒从无症状标本中水平和垂直传播。所有这些数据表明，石鼓耐受宽范围的培养密度，尽管高密度可能是控制该物种NNV爆发的挫折。为了试图了解在压力条件下协调这种敏感性变化的分子途径，我们在模拟和NNV感染条件下对四种组织进行了转录组学分析.除了细胞粘附等异常途径的修饰外，白细胞迁移,细胞因子相互作用，细胞增殖和存活，和自噬,我们还在所分析的四种组织中的三种组织中观察到神经活性配体-受体通路的严重改变.我们的数据还指出，该途径的一些受体是未来药物治疗的潜在候选者，以避免可能在NNV感染后引发鱼类死亡的加剧的免疫反应。
